3D reconstruction of SEM images by use of optical photogrammetry software.

PubMed

Eulitz, Mona; Reiss, Gebhard

2015-08-01

Reconstruction of the three-dimensional (3D) surface of an object to be examined is widely used for structure analysis in science and many biological questions require information about their true 3D structure. For Scanning Electron Microscopy (SEM) there has been no efficient non-destructive solution for reconstruction of the surface morphology to date. The well-known method of recording stereo pair images generates a 3D stereoscope reconstruction of a section, but not of the complete sample surface. We present a simple and non-destructive method of 3D surface reconstruction from SEM samples based on the principles of optical close range photogrammetry. In optical close range photogrammetry a series of overlapping photos is used to generate a 3D model of the surface of an object. We adapted this method to the special SEM requirements. Instead of moving a detector around the object, the object itself was rotated. A series of overlapping photos was stitched and converted into a 3D model using the software commonly used for optical photogrammetry. A rabbit kidney glomerulus was used to demonstrate the workflow of this adaption. The reconstruction produced a realistic and high-resolution 3D mesh model of the glomerular surface. The study showed that SEM micrographs are suitable for 3D reconstruction by optical photogrammetry. This new approach is a simple and useful method of 3D surface reconstruction and suitable for various applications in research and teaching. Copyright © 2015 Elsevier Inc. All rights reserved.

Researching on Real 3d Modeling Constructed with the Oblique Photogrammetry and Terrestrial Photogrammetry

NASA Astrophysics Data System (ADS)

Han, Youmei; Jiao, Minglian; Shijuan

2018-04-01

With the rapid development of the oblique photogrammetry, many cities have built some real 3D model with this technology. Although it has the advantages of short period, high efficiency and good air angle effect, the near ground view angle of these real 3D models are not very good. With increasing development of smart cities, the requirements of reality, practicality and accuracy on real 3D models are becoming higher. How to produce and improve the real 3D models quickly has become one of the hot research directions of geospatial information. To meet this requirement In this paper, Combined with the characteristics of current oblique photogrammetry modeling and the terrestrial photogrammetry, we proposed a new technological process, which consists of close range sensor design, data acquisition and processing. The proposed method is being tested by using oblique photography images acquired. The results confirm the effectiveness of the proposed approach.

Reprocessing Close Range Terrestrial and Uav Photogrammetric Projects with the Dbat Toolbox for Independent Verification and Quality Control

NASA Astrophysics Data System (ADS)

Murtiyoso, A.; Grussenmeyer, P.; Börlin, N.

2017-11-01

Photogrammetry has recently seen a rapid increase in many applications, thanks to developments in computing power and algorithms. Furthermore with the democratisation of UAVs (Unmanned Aerial Vehicles), close range photogrammetry has seen more and more use due to the easier capability to acquire aerial close range images. In terms of photogrammetric processing, many commercial software solutions exist in the market that offer results from user-friendly environments. However, in most commercial solutions, a black-box approach to photogrammetric calculations is often used. This is understandable in light of the proprietary nature of the algorithms, but it may pose a problem if the results need to be validated in an independent manner. In this paper, the Damped Bundle Adjustment Toolbox (DBAT) developed for Matlab was used to reprocess some photogrammetric projects that were processed using the commercial software Agisoft Photoscan. Several scenarios were experimented on in order to see the performance of DBAT in reprocessing terrestrial and UAV close range photogrammetric projects in several configurations of self-calibration setting. Results show that DBAT managed to reprocess PS projects and generate metrics which can be useful for project verification.

Unmanned aircraft systems image collection and computer vision image processing for surveying and mapping that meets professional needs

NASA Astrophysics Data System (ADS)

Peterson, James Preston, II

Unmanned Aerial Systems (UAS) are rapidly blurring the lines between traditional and close range photogrammetry, and between surveying and photogrammetry. UAS are providing an economic platform for performing aerial surveying on small projects. The focus of this research was to describe traditional photogrammetric imagery and Light Detection and Ranging (LiDAR) geospatial products, describe close range photogrammetry (CRP), introduce UAS and computer vision (CV), and investigate whether industry mapping standards for accuracy can be met using UAS collection and CV processing. A 120-acre site was selected and 97 aerial targets were surveyed for evaluation purposes. Four UAS flights of varying heights above ground level (AGL) were executed, and three different target patterns of varying distances between targets were analyzed for compliance with American Society for Photogrammetry and Remote Sensing (ASPRS) and National Standard for Spatial Data Accuracy (NSSDA) mapping standards. This analysis resulted in twelve datasets. Error patterns were evaluated and reasons for these errors were determined. The relationship between the AGL, ground sample distance, target spacing and the root mean square error of the targets is exploited by this research to develop guidelines that use the ASPRS and NSSDA map standard as the template. These guidelines allow the user to select the desired mapping accuracy and determine what target spacing and AGL is required to produce the desired accuracy. These guidelines also address how UAS/CV phenomena affect map accuracy. General guidelines and recommendations are presented that give the user helpful information for planning a UAS flight using CV technology.

Analysis of Photogrammetry Data from ISIM Mockup, June 1, 2007

NASA Technical Reports Server (NTRS)

Nowak, Maria; Hill, Mike

2007-01-01

During ground testing of the Integrated Science Instrument Module (ISIM) for the James Webb Space Telescope (JWST), the ISIM Optics group plans to use a Photogrammetry Measurement System for cryogenic calibration of specific target points on the ISIM composite structure and Science Instrument optical benches and other GSE equipment. This testing will occur in the Space Environmental Systems (SES) chamber at Goddard Space Flight Center. Close range photogrammetry is a 3 dimensional metrology system using triangulation to locate custom targets in 3 coordinates via a collection of digital photographs taken from various locations and orientations. These photos are connected using coded targets, special targets that are recognized by the software and can thus correlate the images to provide a 3 dimensional map of the targets, and scaled via well calibrated scale bars. Photogrammetry solves for the camera location and coordinates of the targets simultaneously through the bundling procedure contained in the V-STARS software.

D Data Acquisition Based on Opencv for Close-Range Photogrammetry Applications

NASA Astrophysics Data System (ADS)

Jurjević, L.; Gašparović, M.

2017-05-01

Development of the technology in the area of the cameras, computers and algorithms for 3D the reconstruction of the objects from the images resulted in the increased popularity of the photogrammetry. Algorithms for the 3D model reconstruction are so advanced that almost anyone can make a 3D model of photographed object. The main goal of this paper is to examine the possibility of obtaining 3D data for the purposes of the close-range photogrammetry applications, based on the open source technologies. All steps of obtaining 3D point cloud are covered in this paper. Special attention is given to the camera calibration, for which two-step process of calibration is used. Both, presented algorithm and accuracy of the point cloud are tested by calculating the spatial difference between referent and produced point clouds. During algorithm testing, robustness and swiftness of obtaining 3D data is noted, and certainly usage of this and similar algorithms has a lot of potential in the real-time application. That is the reason why this research can find its application in the architecture, spatial planning, protection of cultural heritage, forensic, mechanical engineering, traffic management, medicine and other sciences.

Development of biostereometric experiments. [stereometric camera system

NASA Technical Reports Server (NTRS)

Herron, R. E.

1978-01-01

The stereometric camera was designed for close-range techniques in biostereometrics. The camera focusing distance of 360 mm to infinity covers a broad field of close-range photogrammetry. The design provides for a separate unit for the lens system and interchangeable backs on the camera for the use of single frame film exposure, roll-type film cassettes, or glass plates. The system incorporates the use of a surface contrast optical projector.

Training in Innovative Technologies for Close-Range Sensing in Alpine Terrain

NASA Astrophysics Data System (ADS)

Rutzinger, M.; Bremer, M.; Höfle, B.; Hämmerle, M.; Lindenbergh, R.; Oude Elberink, S.; Pirotti, F.; Scaioni, M.; Wujanz, D.; Zieher, T.

2018-05-01

The 2nd international summer school "Close-range sensing techniques in Alpine terrain" was held in July 2017 in Obergurgl, Austria. Participants were trained in selected close-range sensing methods, such as photogrammetry, laser scanning and thermography. The program included keynotes, lectures and hands-on assignments combining field project planning, data acquisition, processing, quality assessment and interpretation. Close-range sensing was applied for different research questions of environmental monitoring in high mountain environments, such as geomorphologic process quantification, natural hazard management and vegetation mapping. The participants completed an online questionnaire evaluating the summer school, its content and organisation, which helps to improve future summer schools.

A new approach towards image based virtual 3D city modeling by using close range photogrammetry

NASA Astrophysics Data System (ADS)

Singh, S. P.; Jain, K.; Mandla, V. R.

2014-05-01

3D city model is a digital representation of the Earth's surface and it's related objects such as building, tree, vegetation, and some manmade feature belonging to urban area. The demand of 3D city modeling is increasing day to day for various engineering and non-engineering applications. Generally three main image based approaches are using for virtual 3D city models generation. In first approach, researchers used Sketch based modeling, second method is Procedural grammar based modeling and third approach is Close range photogrammetry based modeling. Literature study shows that till date, there is no complete solution available to create complete 3D city model by using images. These image based methods also have limitations This paper gives a new approach towards image based virtual 3D city modeling by using close range photogrammetry. This approach is divided into three sections. First, data acquisition process, second is 3D data processing, and third is data combination process. In data acquisition process, a multi-camera setup developed and used for video recording of an area. Image frames created from video data. Minimum required and suitable video image frame selected for 3D processing. In second section, based on close range photogrammetric principles and computer vision techniques, 3D model of area created. In third section, this 3D model exported to adding and merging of other pieces of large area. Scaling and alignment of 3D model was done. After applying the texturing and rendering on this model, a final photo-realistic textured 3D model created. This 3D model transferred into walk-through model or in movie form. Most of the processing steps are automatic. So this method is cost effective and less laborious. Accuracy of this model is good. For this research work, study area is the campus of department of civil engineering, Indian Institute of Technology, Roorkee. This campus acts as a prototype for city. Aerial photography is restricted in many country and high resolution satellite images are costly. In this study, proposed method is based on only simple video recording of area. Thus this proposed method is suitable for 3D city modeling. Photo-realistic, scalable, geo-referenced virtual 3D city model is useful for various kinds of applications such as for planning in navigation, tourism, disasters management, transportations, municipality, urban and environmental managements, real-estate industry. Thus this study will provide a good roadmap for geomatics community to create photo-realistic virtual 3D city model by using close range photogrammetry.

The photogrammetric recording of historic transportation sites.

DOT National Transportation Integrated Search

1983-01-01

The purpose of this study was to evaluate the applicability and accuracy of documentation drawings prepared from close-range me terrestrial photogrammetry and to compare them with the results of traditional documentation techniques which depend on ha...

Creating A 3D urban model by terrestrial laser scanners and photogrammetry techniques: a case study on the historical peninsula of Istanbul

NASA Astrophysics Data System (ADS)

Ergun, Bahadir

2007-07-01

Today, terrestrial laser scanning has been a frequently used methodology for the documentation of historical buildings and cultural heritages. The historical peninsula region is the documentation of historical buildings and cover approximately 1500 ha. Terrestrial laser scanning and close range image photogrammetry techniques are integrated to each other to create a 3D urban model of Istanbul including the most important landmarks and the buildings reflecting the most brilliant areas of Byzantine and Ottoman Empires.

Local and General Monitoring of Forni Glacier (italian Alps) Using Multi-Platform Structure-From Photogrammetry

NASA Astrophysics Data System (ADS)

Scaioni, M.; Corti, M.; Diolaiuti, G.; Fugazza, D.; Cernuschi, M.

2017-09-01

Experts from the University of Milan have been investigating Forni Glacier in the Italian alps for decades, resulting in the archive of a cumbersome mass of observed data. While the analysis of archive maps, medium resolution satellite images and DEM's may provide an overview of the long-term processes, the application of close-range sensing techniques offers the unprecedented opportunity to operate a 4D reconstruction of the glacier geometry at both global and local levels. In the latest years the availability of high-resolution DEM's from stereo-photogrammetry (2007) and UAV-photogrammetry (2014 and 2016) has allowed an improved analysis of the glacier ice-mass balance within time. During summer 2016 a methodology to record the local disruption processes has been investigated. The presence of vertical and sub-vertical surfaces has motivated the use of Structure-from-Motion Photogrammetry from ground-based stations, which yielded results comparable to the ones achieved using a long-range terrestrial laser scanner. This technique may be assumed as benchmarking for accuracy assessment, but is more difficult to be operated in high-mountain areas. Nevertheless, the measurement of GCP's for the terrestrial photogrammetric project has revealed to be a complex task, involving the need of a total station a GNSS. The effect of network geometry on the final output has also been investigated for SfM-Photogrammetry, considering the severe limitations implied in the Alpine environment.

Close Range Uav Accurate Recording and Modeling of St-Pierre Neo-Romanesque Church in Strasbourg (france)

NASA Astrophysics Data System (ADS)

Murtiyoso, A.; Grussenmeyer, P.; Freville, T.

2017-02-01

Close-range photogrammetry is an image-based technique which has often been used for the 3D documentation of heritage objects. Recently, advances in the field of image processing and UAVs (Unmanned Aerial Vehicles) have resulted in a renewed interest in this technique. However, commercially ready-to-use UAVs are often equipped with smaller sensors in order to minimize payload and the quality of the documentation is still an issue. In this research, two commercial UAVs (the Sensefly Albris and DJI Phantom 3 Professional) were setup to record the 19th century St-Pierre-le-Jeune church in Strasbourg, France. Several software solutions (commercial and open source) were used to compare both UAVs' images in terms of calibration, accuracy of external orientation, as well as dense matching. Results show some instability in regards to the calibration of Phantom 3, while the Albris had issues regarding its aerotriangulation results. Despite these shortcomings, both UAVs succeeded in producing dense point clouds of up to a few centimeters in accuracy, which is largely sufficient for the purposes of a city 3D GIS (Geographical Information System). The acquisition of close range images using UAVs also provides greater LoD flexibility in processing. These advantages over other methods such as the TLS (Terrestrial Laser Scanning) or terrestrial close range photogrammetry can be exploited in order for these techniques to complement each other.

Close-range photogrammetry with video cameras

NASA Technical Reports Server (NTRS)

Burner, A. W.; Snow, W. L.; Goad, W. K.

1985-01-01

Examples of photogrammetric measurements made with video cameras uncorrected for electronic and optical lens distortions are presented. The measurement and correction of electronic distortions of video cameras using both bilinear and polynomial interpolation are discussed. Examples showing the relative stability of electronic distortions over long periods of time are presented. Having corrected for electronic distortion, the data are further corrected for lens distortion using the plumb line method. Examples of close-range photogrammetric data taken with video cameras corrected for both electronic and optical lens distortion are presented.

Close-Range Photogrammetry with Video Cameras

NASA Technical Reports Server (NTRS)

Burner, A. W.; Snow, W. L.; Goad, W. K.

1983-01-01

Examples of photogrammetric measurements made with video cameras uncorrected for electronic and optical lens distortions are presented. The measurement and correction of electronic distortions of video cameras using both bilinear and polynomial interpolation are discussed. Examples showing the relative stability of electronic distortions over long periods of time are presented. Having corrected for electronic distortion, the data are further corrected for lens distortion using the plumb line method. Examples of close-range photogrammetric data taken with video cameras corrected for both electronic and optical lens distortion are presented.

Fusion of range camera and photogrammetry: a systematic procedure for improving 3-D models metric accuracy.

PubMed

Guidi, G; Beraldin, J A; Ciofi, S; Atzeni, C

2003-01-01

The generation of three-dimensional (3-D) digital models produced by optical technologies in some cases involves metric errors. This happens when small high-resolution 3-D images are assembled together in order to model a large object. In some applications, as for example 3-D modeling of Cultural Heritage, the problem of metric accuracy is a major issue and no methods are currently available for enhancing it. The authors present a procedure by which the metric reliability of the 3-D model, obtained through iterative alignments of many range maps, can be guaranteed to a known acceptable level. The goal is the integration of the 3-D range camera system with a close range digital photogrammetry technique. The basic idea is to generate a global coordinate system determined by the digital photogrammetric procedure, measuring the spatial coordinates of optical targets placed around the object to be modeled. Such coordinates, set as reference points, allow the proper rigid motion of few key range maps, including a portion of the targets, in the global reference system defined by photogrammetry. The other 3-D images are normally aligned around these locked images with usual iterative algorithms. Experimental results on an anthropomorphic test object, comparing the conventional and the proposed alignment method, are finally reported.

Geomatic methods applied to the study of the front position changes of Johnsons and Hurd Glaciers, Livingston Island, Antarctica, between 1957 and 2013

NASA Astrophysics Data System (ADS)

Rodríguez Cielos, Ricardo; Aguirre de Mata, Julián; Díez Galilea, Andrés; Álvarez Alonso, Marina; Rodríguez Cielos, Pedro; Navarro Valero, Francisco

2016-08-01

Various geomatic measurement techniques can be efficiently combined for surveying glacier fronts. Aerial photographs and satellite images can be used to determine the position of the glacier terminus. If the glacier front is easily accessible, the classic surveys using theodolite or total station, GNSS (Global Navigation Satellite System) techniques, laser-scanner or close-range photogrammetry are possible. When the accessibility to the glacier front is difficult or impossible, close-range photogrammetry proves to be useful, inexpensive and fast. In this paper, a methodology combining photogrammetric methods and other techniques is applied to determine the calving front position of Johnsons Glacier. Images taken in 2013 with an inexpensive nonmetric digital camera are georeferenced to a global coordinate system by measuring, using GNSS techniques, support points in accessible areas close to the glacier front, from which control points in inaccessible points on the glacier surface near its calving front are determined with theodolite using the direct intersection method. The front position changes of Johnsons Glacier during the period 1957-2013, as well as those of the land-terminating fronts of Argentina, Las Palmas and Sally Rocks lobes of Hurd glacier, are determined from different geomatic techniques such as surface-based GNSS measurements, aerial photogrammetry and satellite optical imagery. This provides a set of frontal positions useful, e.g., for glacier dynamics modeling and mass balance studies.Link to the data repository: https://doi.pangaea.de/10.1594/PANGAEA.845379.

Quantifying uncertainty of measuring gully morphological evolution with close-range digital photogrammetry

USDA-ARS?s Scientific Manuscript database

Measurement of geomorphic change may be of interest to researchers and practitioners in a variety of fields including geology, geomorphology, hydrology, engineering, and soil science. Landscapes are often represented by digital elevation models. Surface models generated of the same landscape over a ...

Close-Range Photogrammetry & Next Generation Spacecraft

NASA Technical Reports Server (NTRS)

Pappa, Richard S.

2002-01-01

NASA is focusing renewed attention on the topic of large, ultra-lightweight space structures, also known as 'gossamer' spacecraft. Nearly all of the details of the giant spacecraft are still to be worked out. But it's already clear that one of the most challenging aspects will be developing techniques to align and control these systems after they are deployed in space. A critical part of this process is creating new ground test methods to measure gossamer structures under stationary, deploying and vibrating conditions for validation of corresponding analytical predictions. In addressing this problem, I considered, first of all, the possibility of simply using conventional displacement or vibration sensor that could provide spatial measurements. Next, I turned my attention to photogrammetry, a method of determining the spatial coordinates of objects using photographs. The success of this research and development has convinced me that photogrammetry is the most suitable method to solve the gossamer measurement problem.

A Simple Close Range Photogrammetry Technique to Assess Soil Erosion in the Field

USDA-ARS?s Scientific Manuscript database

Evaluating the performance of a soil erosion prediction model depends on the ability to accurately measure the gain or loss of sediment in an area. Recent development in acquiring detailed surface elevation data (DEM) makes it feasible to assess soil erosion and deposition spatially. Digital photogr...

Investigating the Accuracy of Point Clouds Generated for Rock Surfaces

NASA Astrophysics Data System (ADS)

Seker, D. Z.; Incekara, A. H.

2016-12-01

Point clouds which are produced by means of different techniques are widely used to model the rocks and obtain the properties of rock surfaces like roughness, volume and area. These point clouds can be generated by applying laser scanning and close range photogrammetry techniques. Laser scanning is the most common method to produce point cloud. In this method, laser scanner device produces 3D point cloud at regular intervals. In close range photogrammetry, point cloud can be produced with the help of photographs taken in appropriate conditions depending on developing hardware and software technology. Many photogrammetric software which is open source or not currently provide the generation of point cloud support. Both methods are close to each other in terms of accuracy. Sufficient accuracy in the mm and cm range can be obtained with the help of a qualified digital camera and laser scanner. In both methods, field work is completed in less time than conventional techniques. In close range photogrammetry, any part of rock surfaces can be completely represented owing to overlapping oblique photographs. In contrast to the proximity of the data, these two methods are quite different in terms of cost. In this study, whether or not point cloud produced by photographs can be used instead of point cloud produced by laser scanner device is investigated. In accordance with this purpose, rock surfaces which have complex and irregular shape located in İstanbul Technical University Ayazaga Campus were selected as study object. Selected object is mixture of different rock types and consists of both partly weathered and fresh parts. Study was performed on a part of 30m x 10m rock surface. 2D and 3D analysis were performed for several regions selected from the point clouds of the surface models. 2D analysis is area-based and 3D analysis is volume-based. Analysis conclusions showed that point clouds in both are similar and can be used as alternative to each other. This proved that point cloud produced using photographs which are both economical and enables to produce data in less time can be used in several studies instead of point cloud produced by laser scanner.

Optimization of Close Range Photogrammetry Network Design Applying Fuzzy Computation

NASA Astrophysics Data System (ADS)

Aminia, A. S.

2017-09-01

Measuring object 3D coordinates with optimum accuracy is one of the most important issues in close range photogrammetry. In this context, network design plays an important role in determination of optimum position of imaging stations. This is, however, not a trivial task due to various geometric and radiometric constraints affecting the quality of the measurement network. As a result, most camera stations in the network are defined on a try and error basis based on the user's experience and generic network concept. In this paper, we propose a post-processing task to investigate the quality of camera positions right after image capturing to achieve the best result. To do this, a new fuzzy reasoning approach is adopted, in which the constraints affecting the network design are all modeled. As a result, the position of all camera locations is defined based on fuzzy rules and inappropriate stations are determined. The experiments carried out show that after determination and elimination of the inappropriate images using the proposed fuzzy reasoning system, the accuracy of measurements is improved and enhanced about 17% for the latter network.

Feasibility of Close-Range Photogrammetric Models for Geographic Information System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Luke; /Rice U.

2011-06-22

The objective of this project was to determine the feasibility of using close-range architectural photogrammetry as an alternative three dimensional modeling technique in order to place the digital models in a geographic information system (GIS) at SLAC. With the available equipment and Australis photogrammetry software, the creation of full and accurate models of an example building, Building 281 on SLAC campus, was attempted. After conducting several equipment tests to determine the precision achievable, a complete photogrammetric survey was attempted. The dimensions of the resulting models were then compared against the true dimensions of the building. A complete building model wasmore » not evidenced to be obtainable using the current equipment and software. This failure was likely attributable to the limits of the software rather than the precision of the physical equipment. However, partial models of the building were shown to be accurate and determined to still be usable in a GIS. With further development of the photogrammetric software and survey procedure, the desired generation of a complete three dimensional model is likely still feasible.« less

3D Position and Velocity Vector Computations of Objects Jettisoned from the International Space Station Using Close-Range Photogrammetry Approach

NASA Technical Reports Server (NTRS)

Papanyan, Valeri; Oshle, Edward; Adamo, Daniel

2008-01-01

Measurement of the jettisoned object departure trajectory and velocity vector in the International Space Station (ISS) reference frame is vitally important for prompt evaluation of the object s imminent orbit. We report on the first successful application of photogrammetric analysis of the ISS imagery for the prompt computation of the jettisoned object s position and velocity vectors. As post-EVA analyses examples, we present the Floating Potential Probe (FPP) and the Russian "Orlan" Space Suit jettisons, as well as the near-real-time (provided in several hours after the separation) computations of the Video Stanchion Support Assembly Flight Support Assembly (VSSA-FSA) and Early Ammonia Servicer (EAS) jettisons during the US astronauts space-walk. Standard close-range photogrammetry analysis was used during this EVA to analyze two on-board camera image sequences down-linked from the ISS. In this approach the ISS camera orientations were computed from known coordinates of several reference points on the ISS hardware. Then the position of the jettisoned object for each time-frame was computed from its image in each frame of the video-clips. In another, "quick-look" approach used in near-real time, orientation of the cameras was computed from their position (from the ISS CAD model) and operational data (pan and tilt) then location of the jettisoned object was calculated only for several frames of the two synchronized movies. Keywords: Photogrammetry, International Space Station, jettisons, image analysis.

Issue of data acquisition and processing using short range photogrammetry and terrestrial laser scanning for educational portals and virtual museums based on Wawel cathedral. (Polish Title: Problematyka pozyskiwania i przetwarzania danych fotogrametrycznych i z naziemnego skaningu laserowego na potrzeby tworzenia portali edukacyjnych i wirtualnych muzeów na przykładzie Katedry Wawelskiej)

NASA Astrophysics Data System (ADS)

Mitka, B.; Szelest, P.

2013-12-01

This paper presents the issues related to the acquisition and processing of terrestrial photogrammetry and laser scanning for building educational portals and virtual museums. Discusses the specific requirements of measurement technology and data processing for all kinds of objects, ranging from architecture through sculpture and architectural detail on the fabric and individual museum exhibits. Educational portals and virtual museums require a modern, high-quality visuals (3D models, virtual tours, animations, etc.) supplemented by descriptive content or audio commentary. Source for obtaining such materials are mostly terrestrial laser scanning and photogrammetry as technologies that provide complete information about the presented geometric objects. However, the performance requirements of web services impose severe restrictions on the presented content. It is necessary to use optimalization geometry process to streamline the way of its presentation. Equally important problem concerns the selection of appropriate technology and process measurement data processing presented for each type of objects. Only skillful selection of measuring equipment and data processing tools effectively ensure the achievement of a satisfactory end result. Both terrestrial laser scanning technology and digital close range photogrammetry has its strengths which should be used but also the limitations that must be taken into account in this kind of work. The key is choosing the right scanner for both the measured object and terrain such as pixel size in the performance of his photos.

Kinematic parameter estimation using close range photogrammetry for sport applications

NASA Astrophysics Data System (ADS)

Magre Colorado, Luz Alejandra; Martínez Santos, Juan Carlos

2015-12-01

In this article, we show the development of a low-cost hardware/software system based on close range photogrammetry to track the movement of a person performing weightlifting. The goal is to reduce the costs to the trainers and athletes dedicated to this sport when it comes to analyze the performance of the sportsman and avoid injuries or accidents. We used a web-cam as the data acquisition hardware and develop the software stack in Processing using the OpenCV library. Our algorithm extracts size, position, velocity, and acceleration measurements of the bar along the course of the exercise. We present detailed characteristics of the system with their results in a controlled setting. The current work improves the detection and tracking capabilities from a previous version of this system by using HSV color model instead of RGB. Preliminary results show that the system is able to profile the movement of the bar as well as determine the size, position, velocity, and acceleration values of a marker/target in scene. The average error finding the size of object at four meters of distance is less than 4%, and the error of the acceleration value is 1.01% in average.

a Simulation Tool Assisting the Design of a Close Range Photogrammetry System for the Sardinia Radio Telescope

NASA Astrophysics Data System (ADS)

Buffa, F.; Pinna, A.; Sanna, G.

2016-06-01

The Sardinia Radio Telescope (SRT) is a 64 m diameter antenna, whose primary mirror is equipped with an active surface capable to correct its deformations by means of a thick network of actuators. Close range photogrammetry (CRP) was used to measure the self-load deformations of the SRT primary reflector from its optimal shape, which are requested to be minimized for the radio telescope to operate at full efficiency. In the attempt to achieve such performance, we conceived a near real-time CRP system which requires the cameras to be installed in fixed positions and at the same time to avoid any interference with the antenna operativeness. The design of such system is not a trivial task, and to assist our decision we therefore developed a simulation pipeline to realistically reproduce and evaluate photogrammetric surveys of large structures. The described simulation environment consists of (i) a detailed description of the SRT model, included the measurement points and the camera parameters, (ii) a tool capable of generating realistic images accordingly to the above model, and (iii) a self-calibrating bundle adjustment to evaluate the performance in terms of RMSE of the camera configurations.

Close-range photogrammetry in underground mining ground control

NASA Astrophysics Data System (ADS)

Benton, Donovan J.; Chambers, Amy J.; Raffaldi, Michael J.; Finley, Seth A.; Powers, Mark J.

2016-09-01

Monitoring underground mine deformation and support conditions has traditionally involved visual inspection and geotechnical instrumentation. Monitoring displacements with conventional instrumentation can be expensive and time-consuming, and the number of locations that can be effectively monitored is generally limited. Moreover, conventional methods typically produce vector rather than tensor descriptions of geometry changes. Tensor descriptions can provide greater insight into hazardous ground movements, particularly in recently excavated openings and in older workings that have been negatively impacted by high stress concentrations, time-dependent deformation, or corrosion of ground support elements. To address these issues, researchers with the National Institute for Occupational Safety and Health, Spokane Mining Research Division are developing and evaluating photogrammetric systems for ground control monitoring applications in underground mines. This research has demonstrated that photogrammetric systems can produce millimeter-level measurements that are comparable to conventional displacement-measuring instruments. This paper provides an overview of the beneficial use of close-range photogrammetry for the following three ground control applications in underground mines: monitoring the deformation of surface support, monitoring rock mass movement, and monitoring the corrosion of surface support. Preliminary field analyses, case studies, limitations, and best practices for these applications are also discussed.

Analysis of Photogrammetry Data from ISIM Mockup

NASA Technical Reports Server (NTRS)

Nowak, Maria; Hill, Mike

2007-01-01

During ground testing of the Integrated Science Instrument Module (ISIM) for the James Webb Space Telescope (JWST), the ISIM Optics group plans to use a Photogrammetry Measurement System for cryogenic calibration of specific target points on the ISIM composite structure and Science Instrument optical benches and other GSE equipment. This testing will occur in the Space Environmental Systems (SES) chamber at Goddard Space Flight Center. Close range photogrammetry is a 3 dimensional metrology system using triangulation to locate custom targets in 3 coordinates via a collection of digital photographs taken from various locations and orientations. These photos are connected using coded targets, special targets that are recognized by the software and can thus correlate the images to provide a 3 dimensional map of the targets, and scaled via well calibrated scale bars. Photogrammetry solves for the camera location and coordinates of the targets simultaneously through the bundling procedure contained in the V-STARS software, proprietary software owned by Geodetic Systems Inc. The primary objectives of the metrology performed on the ISIM mock-up were (1) to quantify the accuracy of the INCA3 photogrammetry camera on a representative full scale version of the ISIM structure at ambient temperature by comparing the measurements obtained with this camera to measurements using the Leica laser tracker system and (2), empirically determine the smallest increment of target position movement that can be resolved by the PG camera in the test setup, i.e., precision, or resolution. In addition, the geometrical details of the test setup defined during the mockup testing, such as target locations and camera positions, will contribute to the final design of the photogrammetry system to be used on the ISIM Flight Structure.

The recovery and utilization of space suit range-of-motion data

NASA Technical Reports Server (NTRS)

Reinhardt, AL; Walton, James S.

1988-01-01

A technique for recovering data for the range of motion of a subject wearing a space suit is described along with the validation of this technique on an EVA space suit. Digitized data are automatically acquired from video images of the subject; three-dimensional trajectories are recovered from these data, and can be displayed using three-dimensional computer graphics. Target locations are recovered using a unique video processor and close-range photogrammetry. It is concluded that such data can be used in such applications as the animation of anthropometric computer models.

Aerial monitoring in active mud volcano by UAV technique

NASA Astrophysics Data System (ADS)

Pisciotta, Antonino; Capasso, Giorgio; Madonia, Paolo

2016-04-01

UAV photogrammetry opens various new applications in the close range domain, combining aerial and terrestrial photogrammetry, but also introduces low-cost alternatives to the classical manned aerial photogrammetry. Between 2014 and 2015 tree aerial surveys have been carried out. Using a quadrotor drone, equipped with a compact camera, it was possible to generate high resolution elevation models and orthoimages of The "Salinelle", an active mud volcanoes area, located in territory of Paternò (South Italy). The main risks are related to the damages produced by paroxysmal events. Mud volcanoes show different cyclic phases of activity, including catastrophic events and periods of relative quiescence characterized by moderate activity. Ejected materials often are a mud slurry of fine solids suspended in liquids which may include water and hydrocarbon fluids, the bulk of released gases are carbon dioxide, with some methane and nitrogen, usually pond-shaped of variable dimension (from centimeters to meters in diameter). The scope of the presented work is the performance evaluation of a UAV system that was built to rapidly and autonomously acquire mobile three-dimensional (3D) mapping data in a volcanic monitoring scenario.

From Architectural Photogrammetry Toward Digital Architectural Heritage Education

NASA Astrophysics Data System (ADS)

Baik, A.; Alitany, A.

2018-05-01

This paper considers the potential of using the documentation approach proposed for the heritage buildings in Historic Jeddah, Saudi Arabia (as a case study) by using the close-range photogrammetry / the Architectural Photogrammetry techniques as a new academic experiment in digital architectural heritage education. Moreover, different than most of engineering educational techniques related to architecture education, this paper will be focusing on the 3-D data acquisition technology as a tool to document and to learn the principals of the digital architectural heritage documentation. The objective of this research is to integrate the 3-D modelling and visualisation knowledge for the purposes of identifying, designing and evaluating an effective engineering educational experiment. Furthermore, the students will learn and understand the characteristics of the historical building while learning more advanced 3-D modelling and visualisation techniques. It can be argued that many of these technologies alone are difficult to improve the education; therefore, it is important to integrate them in an educational framework. This should be in line with the educational ethos of the academic discipline. Recently, a number of these technologies and methods have been effectively used in education sectors and other purposes; such as in the virtual museum. However, these methods are not directly coincided with the traditional education and teaching architecture. This research will be introduced the proposed approach as a new academic experiment in the architecture education sector. The new teaching approach will be based on the Architectural Photogrammetry to provide semantically rich models. The academic experiment will require students to have suitable knowledge in both Photogrammetry applications to engage with the process.

Surveying a Landslide in a Road Embankment Using Unmanned Aerial Vehicle Photogrammetry

NASA Astrophysics Data System (ADS)

Carvajal, F.; Agüera, F.; Pérez, M.

2011-09-01

Most of the works of civil engineering, and some others applications, need to be designed using a basic cartography with a suitable scale to the accuracy and extension of the plot.The Unmanned Aerial Vehicle (UAV) Photogrammetry covers the gap between classical manned aerial photogrammetry and hand- made surveying techniques because it works in the close-range domain, combining aerial and terrestrial photogrammetry, but also introduces low-cost alternatives. The aim of this work is developing of an accurate and low-cost method to characterize landslides located on the size of a road. It was applied at the kilometric point 339 belonging to the A92 dual carriageway, in the Abla municipal term, province of Almeria, Spain. A photogrammetric project was carried out from a set of images taken from an md4-200 Microdrones with an on-board calibrated camera 12 Megapixels Pentax Optio A40. The flight was previously planned to cover the whole extension of the embankment with three passes composed of 18 photos each one. All the images were taken with the vertical axe and it was registered 85% and 60% longitudinal and transversal overlaps respectively. The accuracy of the products, with planimetric and altimetric errors of 0.049 and 0.108m repectively, lets to take measurements of the landslide and projecting preventive and palliative actuations.

Photographic assessment of retroreflective film properties

NASA Astrophysics Data System (ADS)

Burgess, G.; Shortis, M. R.; Scott, P.

2011-09-01

Retroreflective film is used widely for target manufacture in close-range photogrammetry, especially where high precision is required for applications in industrial or engineering metrology. 3M Scotchlite 7610 high gain reflective sheeting is the gold standard for retroreflective targets because of the high level of response for incidence angles up to 60°. Retroreflective film is now widely used in the transport industry for signage and many other types of film have become available. This study reports on the performance of six types of retroreflective sheeting, including 7610, based on published metrics for reflectance. Measurements were made using a camera and flash, so as to be directly applicable to photogrammetry. Analysis of the results from this project and the assessment of previous research indicates that the use of standards is essential to enable a valid comparison of retroreflective performance.

3D model tools for architecture and archaeology reconstruction

NASA Astrophysics Data System (ADS)

Vlad, Ioan; Herban, Ioan Sorin; Stoian, Mircea; Vilceanu, Clara-Beatrice

2016-06-01

The main objective of architectural and patrimonial survey is to provide a precise documentation of the status quo of the surveyed objects (monuments, buildings, archaeological object and sites) for preservation and protection, for scientific studies and restoration purposes, for the presentation to the general public. Cultural heritage documentation includes an interdisciplinary approach having as purpose an overall understanding of the object itself and an integration of the information which characterize it. The accuracy and the precision of the model are directly influenced by the quality of the measurements realized on field and by the quality of the software. The software is in the process of continuous development, which brings many improvements. On the other side, compared to aerial photogrammetry, close range photogrammetry and particularly architectural photogrammetry is not limited to vertical photographs with special cameras. The methodology of terrestrial photogrammetry has changed significantly and various photographic acquisitions are widely in use. In this context, the present paper brings forward a comparative study of TLS (Terrestrial Laser Scanner) and digital photogrammetry for 3D modeling. The authors take into account the accuracy of the 3D models obtained, the overall costs involved for each technology and method and the 4th dimension - time. The paper proves its applicability as photogrammetric technologies are nowadays used at a large scale for obtaining the 3D model of cultural heritage objects, efficacious in their assessment and monitoring, thus contributing to historic conservation. Its importance also lies in highlighting the advantages and disadvantages of each method used - very important issue for both the industrial and scientific segment when facing decisions such as in which technology to invest more research and funds.

Research of cartographer laser SLAM algorithm

NASA Astrophysics Data System (ADS)

Xu, Bo; Liu, Zhengjun; Fu, Yiran; Zhang, Changsai

2017-11-01

As the indoor is a relatively closed and small space, total station, GPS, close-range photogrammetry technology is difficult to achieve fast and accurate indoor three-dimensional space reconstruction task. LIDAR SLAM technology does not rely on the external environment a priori knowledge, only use their own portable lidar, IMU, odometer and other sensors to establish an independent environment map, a good solution to this problem. This paper analyzes the Google Cartographer laser SLAM algorithm from the point cloud matching and closed loop detection. Finally, the algorithm is presented in the 3D visualization tool RViz from the data acquisition and processing to create the environment map, complete the SLAM technology and realize the process of indoor threedimensional space reconstruction

Model Predictions and Observed Performance of JWST's Cryogenic Position Metrology System

NASA Technical Reports Server (NTRS)

Lunt, Sharon R.; Rhodes, David; DiAntonio, Andrew; Boland, John; Wells, Conrad; Gigliotti, Trevis; Johanning, Gary

2016-01-01

The James Webb Space Telescope cryogenic testing requires measurement systems that both obtain a very high degree of accuracy and can function in that environment. Close-range photogrammetry was identified as meeting those criteria. Testing the capability of a close-range photogrammetric system prior to its existence is a challenging problem. Computer simulation was chosen over building a scaled mock-up to allow for increased flexibility in testing various configurations. Extensive validation work was done to ensure that the actual as-built system meet accuracy and repeatability requirements. The simulated image data predicted the uncertainty in measurement to be within specification and this prediction was borne out experimentally. Uncertainty at all levels was verified experimentally to be less than 0.1 millimeters.

High-speed photogrammetry system for measuring the kinematics of insect wings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wallace, Iain D.; Lawson, Nicholas J.; Harvey, Andrew R.

2006-06-10

We describe and characterize an experimental system to perform shape measurements on deformable objects using high-speed close-range photogrammetry. The eventual application is to extract the kinematics of several marked points on an insect wing during tethered and hovering flight. We investigate the performance of the system with a small number of views and determine an empirical relation between the mean pixel error of the optimization routine and the position error. Velocity and acceleration are calculated by numerical differencing, and their relation to the position errors is verified. For a field of view of {approx}40mmx40 mm, a rms accuracy of 30more » {mu}m in position, 150 mm/s in velocity, and 750 m/s2 in acceleration at 5000 frames/s is achieved. This accuracy is sufficient to measure the kinematics of hoverfly flight.« less

A photogrammetry-based system for 3D surface reconstruction of prosthetics and orthotics.

PubMed

Li, Guang-kun; Gao, Fan; Wang, Zhi-gang

2011-01-01

The objective of this study is to develop an innovative close range digital photogrammetry (CRDP) system using the commercial digital SLR cameras to measure and reconstruct the 3D surface of prosthetics and orthotics. This paper describes the instrumentation, techniques and preliminary results of the proposed system. The technique works by taking pictures of the object from multiple view angles. The series of pictures were post-processed via feature point extraction, point match and 3D surface reconstruction. In comparison with the traditional method such as laser scanning, the major advantages of our instrument include the lower cost, compact and easy-to-use hardware, satisfactory measurement accuracy, and significantly less measurement time. Besides its potential applications in prosthetics and orthotics surface measurement, the simple setup and its ease of use will make it suitable for various 3D surface reconstructions.

Development of distortion measurement system for large deployable antenna via photogrammetry in vacuum and cryogenic environment

NASA Astrophysics Data System (ADS)

Zhang, Pengsong; Jiang, Shanping; Yang, Linhua; Zhang, Bolun

2018-01-01

In order to meet the requirement of high precision thermal distortion measurement foraΦ4.2m deployable mesh antenna of satellite in vacuum and cryogenic environment, based on Digital Close-range Photogrammetry and Space Environment Test Technology of Spacecraft, a large scale antenna distortion measurement system under vacuum and cryogenic environment is developed in this paper. The antenna Distortion measurement system (ADMS) is the first domestic independently developed thermal distortion measurement system for large antenna, which has successfully solved non-contact high precision distortion measurement problem in large spacecraft structure under vacuum and cryogenic environment. The measurement accuracy of ADMS is better than 50 μm/5m, which has reached international advanced level. The experimental results show that the measurement system has great advantages in large structural measurement of spacecrafts, and also has broad application prospects in space or other related fields.

Study on the Feasibility of RGB Substitute CIR for Automatic Removal Vegetation Occlusion Based on Ground Close-Range Building Images

NASA Astrophysics Data System (ADS)

Li, C.; Li, F.; Liu, Y.; Li, X.; Liu, P.; Xiao, B.

2012-07-01

Building 3D reconstruction based on ground remote sensing data (image, video and lidar) inevitably faces the problem that buildings are always occluded by vegetation, so how to automatically remove and repair vegetation occlusion is a very important preprocessing work for image understanding, compute vision and digital photogrammetry. In the traditional multispectral remote sensing which is achieved by aeronautics and space platforms, the Red and Near-infrared (NIR) bands, such as NDVI (Normalized Difference Vegetation Index), are useful to distinguish vegetation and clouds, amongst other targets. However, especially in the ground platform, CIR (Color Infra Red) is little utilized by compute vision and digital photogrammetry which usually only take true color RBG into account. Therefore whether CIR is necessary for vegetation segmentation or not has significance in that most of close-range cameras don't contain such NIR band. Moreover, the CIE L*a*b color space, which transform from RGB, seems not of much interest by photogrammetrists despite its powerfulness in image classification and analysis. So, CIE (L, a, b) feature and support vector machine (SVM) is suggested for vegetation segmentation to substitute for CIR. Finally, experimental results of visual effect and automation are given. The conclusion is that it's feasible to remove and segment vegetation occlusion without NIR band. This work should pave the way for texture reconstruction and repair for future 3D reconstruction.

Network design and quality checks in automatic orientation of close-range photogrammetric blocks.

PubMed

Dall'Asta, Elisa; Thoeni, Klaus; Santise, Marina; Forlani, Gianfranco; Giacomini, Anna; Roncella, Riccardo

2015-04-03

Due to the recent improvements of automatic measurement procedures in photogrammetry, multi-view 3D reconstruction technologies are becoming a favourite survey tool. Rapidly widening structure-from-motion (SfM) software packages offer significantly easier image processing workflows than traditional photogrammetry packages. However, while most orientation and surface reconstruction strategies will almost always succeed in any given task, estimating the quality of the result is, to some extent, still an open issue. An assessment of the precision and reliability of block orientation is necessary and should be included in every processing pipeline. Such a need was clearly felt from the results of close-range photogrammetric surveys of in situ full-scale and laboratory-scale experiments. In order to study the impact of the block control and the camera network design on the block orientation accuracy, a series of Monte Carlo simulations was performed. Two image block configurations were investigated: a single pseudo-normal strip and a circular highly-convergent block. The influence of surveying and data processing choices, such as the number and accuracy of the ground control points, autofocus and camera calibration was investigated. The research highlights the most significant aspects and processes to be taken into account for adequate in situ and laboratory surveys, when modern SfM software packages are used, and evaluates their effect on the quality of the results of the surface reconstruction.

Stability analysis of chalk sea cliffs using UAV photogrammetry

NASA Astrophysics Data System (ADS)

Barlow, John; Gilham, Jamie

2017-04-01

Cliff erosion and instability poses a significant hazard to communities and infrastructure located is coastal areas. We use point cloud and spectral data derived from close range digital photogrammetry to assess the stability of chalk sea cliffs located at Telscombe, UK. Data captured from an unmanned aerial vehicle (UAV) were used to generate dense point clouds for a 712 m section of cliff face which ranges from 20 to 49 m in height. Generated models fitted our ground control network within a standard error of 0.03 m. Structural features such as joints, bedding planes, and faults were manually mapped and are consistent with results from other studies that have been conducted using direct measurement in the field. Kinematic analysis of these data was used to identify the primary modes of failure at the site. Our results indicate that wedge failure is by far the most likely mode of slope instability. An analysis of sequential surveys taken from the summer of 2016 to the winter of 2017 indicate several large failures have occurred at the site. We establish the volume of failure through change detection between sequential data sets and use back analysis to determine the strength of shear surfaces for each failure. Our results show that data capture through UAV photogrammetry can provide useful information for slope stability analysis over long sections of cliff. The use of this technology offers significant benefits in equipment costs and field time over existing methods.

Photogrammetry and remote sensing education subjects

NASA Astrophysics Data System (ADS)

Lazaridou, Maria A.; Karagianni, Aikaterini Ch.

2017-09-01

The rapid technologic advances in the scientific areas of photogrammetry and remote sensing require continuous readjustments at the educational programs and their implementation. The teaching teamwork should deal with the challenge to offer the volume of the knowledge without preventing the understanding of principles and methods and also to introduce "new" knowledge (advances, trends) followed by evaluation and presentation of relevant applications. This is of particular importance for a Civil Engineering Faculty as this in Aristotle University of Thessaloniki, as the framework of Photogrammetry and Remote Sensing is closely connected with applications in the four educational Divisions of the Faculty. This paper refers to the above and includes subjects of organizing the courses in photogrammetry and remote sensing in the Civil Engineering Faculty of Aristotle University of Thessaloniki. A scheme of the general curriculum as well the teaching aims and methods are also presented.

Testing photogrammetry-based techniques for three-dimensional surface documentation in forensic pathology.

PubMed

Urbanová, Petra; Hejna, Petr; Jurda, Mikoláš

2015-05-01

Three-dimensional surface technologies particularly close range photogrammetry and optical surface scanning have recently advanced into affordable, flexible and accurate techniques. Forensic postmortem investigation as performed on a daily basis, however, has not yet fully benefited from their potentials. In the present paper, we tested two approaches to 3D external body documentation - digital camera-based photogrammetry combined with commercial Agisoft PhotoScan(®) software and stereophotogrammetry-based Vectra H1(®), a portable handheld surface scanner. In order to conduct the study three human subjects were selected, a living person, a 25-year-old female, and two forensic cases admitted for postmortem examination at the Department of Forensic Medicine, Hradec Králové, Czech Republic (both 63-year-old males), one dead to traumatic, self-inflicted, injuries (suicide by hanging), the other diagnosed with the heart failure. All three cases were photographed in 360° manner with a Nikon 7000 digital camera and simultaneously documented with the handheld scanner. In addition to having recorded the pre-autopsy phase of the forensic cases, both techniques were employed in various stages of autopsy. The sets of collected digital images (approximately 100 per case) were further processed to generate point clouds and 3D meshes. Final 3D models (a pair per individual) were counted for numbers of points and polygons, then assessed visually and compared quantitatively using ICP alignment algorithm and a cloud point comparison technique based on closest point to point distances. Both techniques were proven to be easy to handle and equally laborious. While collecting the images at autopsy took around 20min, the post-processing was much more time-demanding and required up to 10h of computation time. Moreover, for the full-body scanning the post-processing of the handheld scanner required rather time-consuming manual image alignment. In all instances the applied approaches produced high-resolution photorealistic, real sized or easy to calibrate 3D surface models. Both methods equally failed when the scanned body surface was covered with body hair or reflective moist areas. Still, it can be concluded that single camera close range photogrammetry and optical surface scanning using Vectra H1 scanner represent relatively low-cost solutions which were shown to be beneficial for postmortem body documentation in forensic pathology. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A case study on the historical peninsula of Istanbul based on three-dimensional modeling by using photogrammetry and terrestrial laser scanning.

PubMed

Ergun, Bahadir; Sahin, Cumhur; Baz, Ibrahim; Ustuntas, Taner

2010-06-01

Terrestrial laser scanning is a popular methodology that is used frequently in the process of documenting historical buildings and cultural heritage. The historical peninsula region sprawls over an area of approximately 1,500 ha and is one of the main aggregate areas of the historical buildings in Istanbul. In this study, terrestrial laser scanning and close range photogrammetry techniques are integrated into each other to create a 3D city model of this part of Istanbul, including some of the buildings that represent the most brilliant areas of Byzantine and Ottoman Empires. Several terrestrial laser scanners with their different specifications were used to solve various geometric scanning problems for distinct areas of the subject city. Photogrammetric method was used for the documentation of the façades of these historical buildings for architectural purposes. This study differentiates itself from the similar ones by its application process that focuses on the geometry, the building texture, and density of the study area. Nowadays, the largest-scale studies among 3D modeling studies, in terms of the methodology of measurement, are urban modeling studies. Because of this large scale, the application of 3D urban modeling studies is executed in a gradual way. In this study, a modeling method based on the façades of the streets was used. In addition, the complimentary elements for the process of modeling were combined in several ways. A street model was presented as a sample, as being the subject of the applied study. In our application of 3D modeling, the modeling based on close range photogrammetry and the data of combined calibration with the data of terrestrial laser scanner were used in a compatible way. The final work was formed with the pedestal data for 3D visualization.

Risks and advantages of using surface laser photogrammetry on free-ranging marine organisms: a case study on white sharks Carcharodon carcharias.

PubMed

Leurs, G; O'Connell, C P; Andreotti, S; Rutzen, M; Vonk Noordegraaf, H

2015-06-01

This study employed a non-lethal measurement tool, which combined an existing photo-identification technique with a surface, parallel laser photogrammetry technique, to accurately estimate the size of free-ranging white sharks Carcharodon carcharias. Findings confirmed the hypothesis that surface laser photogrammetry is more accurate than crew-based estimations that utilized a shark cage of known size as a reference tool. Furthermore, field implementation also revealed that the photographer's angle of reference and the shark's body curvature could greatly influence technique accuracy, exposing two limitations. The findings showed minor inconsistencies with previous studies that examined pre-caudal to total length ratios of dead specimens. This study suggests that surface laser photogrammetry can successfully increase length estimation accuracy and illustrates the potential utility of this technique for growth and stock assessments on free-ranging marine organisms, which will lead to an improvement of the adaptive management of the species. © 2015 The Fisheries Society of the British Isles.

Technical note: 3D from standard digital photography of human crania-a preliminary assessment.

PubMed

Katz, David; Friess, Martin

2014-05-01

This study assessed three-dimensional (3D) photogrammetry as a tool for capturing and quantifying human skull morphology. While virtual reconstruction with 3D surface scanning technology has become an accepted part of the paleoanthropologist's tool kit, recent advances in 3D photogrammetry make it a potential alternative to dedicated surface scanners. The principal advantages of photogrammetry are more rapid raw data collection, simplicity and portability of setup, and reduced equipment costs. We tested the precision and repeatability of 3D photogrammetry by comparing digital models of human crania reconstructed from conventional, 2D digital photographs to those generated using a 3D surface scanner. Overall, the photogrammetry and scanner meshes showed low degrees of deviation from one another. Surface area estimates derived from photogrammetry models tended to be slightly larger. Landmark configurations generally did not cluster together based upon whether the reconstruction was created with photogrammetry or surface scanning technology. Average deviations of landmark coordinates recorded on photogrammetry models were within the generally allowable range of error in osteometry. Thus, while dependent upon the needs of the particular research project, 3D photogrammetry appears to be a suitable, lower-cost alternative to 3D imaging and scanning options. Copyright © 2014 Wiley Periodicals, Inc.

Photogrammetry and Its Potential Application in Medical Science on the Basis of Selected Literature.

PubMed

Ey-Chmielewska, Halina; Chruściel-Nogalska, Małgorzata; Frączak, Bogumiła

2015-01-01

Photogrammetry is a science and technology which allows quantitative traits to be determined, i.e. the reproduction of object shapes, sizes and positions on the basis of their photographs. Images can be recorded in a wide range of wavelengths of electromagnetic radiation. The most common is the visible range, but near- and medium-infrared, thermal infrared, microwaves and X-rays are also used. The importance of photogrammetry has increased with the development of computer software. Digital image processing and real-time measurement have allowed the automation of many complex manufacturing processes. Photogrammetry has been widely used in many areas, especially in geodesy and cartography. In medicine, this method is used for measuring the widely understood human body for the planning and monitoring of therapeutic treatment and its results. Digital images obtained from optical-electronic sensors combined with computer technology have the potential of objective measurement thanks to the remote nature of the data acquisition, with no contact with the measured object and with high accuracy. Photogrammetry also allows the adoption of common standards for archiving and processing patient data.

The application of multi-baseline digital close-range photogrammetry in three-dimensional imaging and measurement of dental casts.

PubMed

Fu, Xiaoming; Peng, Chun; Li, Zan; Liu, Shan; Tan, Minmin; Song, Jinlin

2017-01-01

To explore a new technique for reconstructing and measuring three-dimensional (3D) models of orthodontic plaster casts using multi-baseline digital close-range photogrammetry (MBDCRP) with a single-lens reflex camera. Thirty sets of orthodontic plaster casts that do not exhibit severe horizontal overlap (>2 mm) between any two teeth were recorded by a single-lens reflex camera with 72 pictures taken in different directions. The 3D models of these casts were reconstructed and measured using the open source software MeshLab. These parameters, including mesio-distal crown diameter, arch width, and arch perimeter, were recorded six times on both the 3D digital models and on plaster casts by two examiners. Statistical analysis was carried out using the Bland-Altman method to measure agreement between the novel method and the traditional calliper method by calculating the differences between mean values. The average differences between the measurements of the photogrammetric 3D models and the plaster casts were 0.011-0.402mm. The mean differences between measurements obtained by the photogrammetric 3D models and the dental casts were not significant except for the lower arch perimeter (P>0.05), and all the differences were regarded as clinically acceptable (<0.5 mm). Measurements obtained by MBDCRP are compared well with those obtained from plaster casts, indicating that MBDCRP is an alternate way to store and measure dental plaster casts without severe horizontal overlap between any two teeth.

Panoramic imaging and virtual reality — filling the gaps between the lines

NASA Astrophysics Data System (ADS)

Chapman, David; Deacon, Andrew

Close range photogrammetry projects rely upon a clear and unambiguous specification of end-user requirements to inform decisions relating to the format, coverage, accuracy and complexity of the final deliverable. Invariably such deliverables will be a partial and incomplete abstraction of the real world where the benefits of higher accuracy and increased complexity must be traded against the cost of the project. As photogrammetric technologies move into the digital era, computerisation offers opportunities for the photogrammetrist to revisit established mapping traditions in order to explore new markets. One such market is that for three-dimensional Virtual Reality (VR) models for clients who have previously had little exposure to the capabilities, and limitations, of photogrammetry and may have radically different views on the cost/benefit trade-offs in producing geometric models. This paper will present some examples of the authors' recent experience of such markets, drawn from a number of research and commercial projects directed towards the modelling of complex man-made objects. This experience seems to indicate that suitably configured digital image archives may form an important deliverable for a wide range of photogrammetric projects and supplement, or even replace, more traditional CAD models.

Mapping Eroded Areas on Mountain Grassland with Terrestrial Photogrammetry and Object-Based Image Analysis

NASA Astrophysics Data System (ADS)

Mayr, Andreas; Rutzinger, Martin; Bremer, Magnus; Geitner, Clemens

2016-06-01

In the Alps as well as in other mountain regions steep grassland is frequently affected by shallow erosion. Often small landslides or snow movements displace the vegetation together with soil and/or unconsolidated material. This results in bare earth surface patches within the grass covered slope. Close-range and remote sensing techniques are promising for both mapping and monitoring these eroded areas. This is essential for a better geomorphological process understanding, to assess past and recent developments, and to plan mitigation measures. Recent developments in image matching techniques make it feasible to produce high resolution orthophotos and digital elevation models from terrestrial oblique images. In this paper we propose to delineate the boundary of eroded areas for selected scenes of a study area, using close-range photogrammetric data. Striving for an efficient, objective and reproducible workflow for this task, we developed an approach for automated classification of the scenes into the classes grass and eroded. We propose an object-based image analysis (OBIA) workflow which consists of image segmentation and automated threshold selection for classification using the Excess Green Vegetation Index (ExG). The automated workflow is tested with ten different scenes. Compared to a manual classification, grass and eroded areas are classified with an overall accuracy between 90.7% and 95.5%, depending on the scene. The methods proved to be insensitive to differences in illumination of the scenes and greenness of the grass. The proposed workflow reduces user interaction and is transferable to other study areas. We conclude that close-range photogrammetry is a valuable low-cost tool for mapping this type of eroded areas in the field with a high level of detail and quality. In future, the output will be used as ground truth for an area-wide mapping of eroded areas in coarser resolution aerial orthophotos acquired at the same time.

Photogrammetric Applications of Immersive Video Cameras

NASA Astrophysics Data System (ADS)

Kwiatek, K.; Tokarczyk, R.

2014-05-01

The paper investigates immersive videography and its application in close-range photogrammetry. Immersive video involves the capture of a live-action scene that presents a 360° field of view. It is recorded simultaneously by multiple cameras or microlenses, where the principal point of each camera is offset from the rotating axis of the device. This issue causes problems when stitching together individual frames of video separated from particular cameras, however there are ways to overcome it and applying immersive cameras in photogrammetry provides a new potential. The paper presents two applications of immersive video in photogrammetry. At first, the creation of a low-cost mobile mapping system based on Ladybug®3 and GPS device is discussed. The amount of panoramas is much too high for photogrammetric purposes as the base line between spherical panoramas is around 1 metre. More than 92 000 panoramas were recorded in one Polish region of Czarny Dunajec and the measurements from panoramas enable the user to measure the area of outdoors (adverting structures) and billboards. A new law is being created in order to limit the number of illegal advertising structures in the Polish landscape and immersive video recorded in a short period of time is a candidate for economical and flexible measurements off-site. The second approach is a generation of 3d video-based reconstructions of heritage sites based on immersive video (structure from immersive video). A mobile camera mounted on a tripod dolly was used to record the interior scene and immersive video, separated into thousands of still panoramas, was converted from video into 3d objects using Agisoft Photoscan Professional. The findings from these experiments demonstrated that immersive photogrammetry seems to be a flexible and prompt method of 3d modelling and provides promising features for mobile mapping systems.

Virtual rough samples to test 3D nanometer-scale scanning electron microscopy stereo photogrammetry.

PubMed

Villarrubia, J S; Tondare, V N; Vladár, A E

2016-01-01

The combination of scanning electron microscopy for high spatial resolution, images from multiple angles to provide 3D information, and commercially available stereo photogrammetry software for 3D reconstruction offers promise for nanometer-scale dimensional metrology in 3D. A method is described to test 3D photogrammetry software by the use of virtual samples-mathematical samples from which simulated images are made for use as inputs to the software under test. The virtual sample is constructed by wrapping a rough skin with any desired power spectral density around a smooth near-trapezoidal line with rounded top corners. Reconstruction is performed with images simulated from different angular viewpoints. The software's reconstructed 3D model is then compared to the known geometry of the virtual sample. Three commercial photogrammetry software packages were tested. Two of them produced results for line height and width that were within close to 1 nm of the correct values. All of the packages exhibited some difficulty in reconstructing details of the surface roughness.

Performance Analysis of the SIFT Operator for Automatic Feature Extraction and Matching in Photogrammetric Applications.

PubMed

Lingua, Andrea; Marenchino, Davide; Nex, Francesco

2009-01-01

In the photogrammetry field, interest in region detectors, which are widely used in Computer Vision, is quickly increasing due to the availability of new techniques. Images acquired by Mobile Mapping Technology, Oblique Photogrammetric Cameras or Unmanned Aerial Vehicles do not observe normal acquisition conditions. Feature extraction and matching techniques, which are traditionally used in photogrammetry, are usually inefficient for these applications as they are unable to provide reliable results under extreme geometrical conditions (convergent taking geometry, strong affine transformations, etc.) and for bad-textured images. A performance analysis of the SIFT technique in aerial and close-range photogrammetric applications is presented in this paper. The goal is to establish the suitability of the SIFT technique for automatic tie point extraction and approximate DSM (Digital Surface Model) generation. First, the performances of the SIFT operator have been compared with those provided by feature extraction and matching techniques used in photogrammetry. All these techniques have been implemented by the authors and validated on aerial and terrestrial images. Moreover, an auto-adaptive version of the SIFT operator has been developed, in order to improve the performances of the SIFT detector in relation to the texture of the images. The Auto-Adaptive SIFT operator (A(2) SIFT) has been validated on several aerial images, with particular attention to large scale aerial images acquired using mini-UAV systems.

Combination of UAV and terrestrial photogrammetry to assess rapid glacier evolution and map glacier hazards

NASA Astrophysics Data System (ADS)

Fugazza, Davide; Scaioni, Marco; Corti, Manuel; D'Agata, Carlo; Azzoni, Roberto Sergio; Cernuschi, Massimo; Smiraglia, Claudio; Diolaiuti, Guglielmina Adele

2018-04-01

Tourists and hikers visiting glaciers all year round face hazards such as sudden terminus collapses, typical of such a dynamically evolving environment. In this study, we analyzed the potential of different survey techniques to analyze hazards of the Forni Glacier, an important geosite located in Stelvio Park (Italian Alps). We carried out surveys in the 2016 ablation season and compared point clouds generated from an unmanned aerial vehicle (UAV) survey, close-range photogrammetry and terrestrial laser scanning (TLS). To investigate the evolution of glacier hazards and evaluate the glacier thinning rate, we also used UAV data collected in 2014 and a digital elevation model (DEM) created from an aerial photogrammetric survey of 2007. We found that the integration between terrestrial and UAV photogrammetry is ideal for mapping hazards related to the glacier collapse, while TLS is affected by occlusions and is logistically complex in glacial terrain. Photogrammetric techniques can therefore replace TLS for glacier studies and UAV-based DEMs hold potential for becoming a standard tool in the investigation of glacier thickness changes. Based on our data sets, an increase in the size of collapses was found over the study period, and the glacier thinning rates went from 4.55 ± 0.24 m a-1 between 2007 and 2014 to 5.20 ± 1.11 m a-1 between 2014 and 2016.

Network Design in Close-Range Photogrammetry with Short Baseline Images

NASA Astrophysics Data System (ADS)

Barazzetti, L.

2017-08-01

The avaibility of automated software for image-based 3D modelling has changed the way people acquire images for photogrammetric applications. Short baseline images are required to match image points with SIFT-like algorithms, obtaining more images than those necessary for "old fashioned" photogrammetric projects based on manual measurements. This paper describes some considerations on network design for short baseline image sequences, especially on precision and reliability of bundle adjustment. Simulated results reveal that the large number of 3D points used for image orientation has very limited impact on network precision.

Drone photogrammetry for geological research: field digital stratigraphic logs for turbiditic reservoir analog studies in Calabria, Southern Italy.

NASA Astrophysics Data System (ADS)

Guillois, Maxime; Brocheray, Sandra; Paron, Paolo

2017-04-01

Drone technology combined with new algorithms like Structure from Motion (SfM) has revived and expanded the uses of photogrammetry bringing new flexibility and the capacity to carry on close range photogrammetry to inaccessible areas. This characteristics are particularly appealing in field geology offering the option to reconstruct continuous digital outcrop models of vertical or difficult to reach outcrops. In this light we present the results of a digital outcrop modelling of a Miocene turbiditic system (mainly sandstone) in Calabria (Southern Italy) generated through field data collected by means of a light-weight commercial drone, a detailed geological field survey and cloud point photogrammetric analyses comparing different software for this purpose (Agisoft Photoscan, Drone deploy, Arc3D). The geological model has been used as an input for preliminary reservoir modelling. We generated digital geological sections (stratigraphic logs) of 1,200 m of sections using expert digital image and terrain model interprepation from the DTM generated with drone data, with the goal to reconstruct the real thickness of each layer. We then compared the results with previously created detailed field geological cross sections. The comparison between drone-derived sections and field-survey sections shows a global accuracy of the thickness ranging between 1% to 10%. Although this new methodology still has to be validated in other morpho-lithological context it already demonstrating its usefulness for preliminary geological outcrop investigation and modelling in remote areas. We also compared the different softwares used and we made recommendations for future deployment. This research has been made possible thanks to a collaboration between UNESCO-IHE, The Netherlands, and UniLaSalle Beauvais, France.

Applications of low altitude photogrammetry for morphometry, displacements, and landform modeling

NASA Astrophysics Data System (ADS)

Gomez, F. G.; Polun, S. G.; Hickcox, K.; Miles, C.; Delisle, C.; Beem, J. R.

2016-12-01

Low-altitude aerial surveying is emerging as a tool that greatly improves the ease and efficiency of measuring landforms for quantitative geomorphic analyses. High-resolution, close-range photogrammetry produces dense, 3-dimensional point clouds that facilitate the construction of digital surface models, as well as a potential means of classifying ground targets using spatial structure. This study presents results from recent applications of UAS-based photogrammetry, including high resolution surface morphometry of a lava flow, repeat-pass applications to mass movements, and fault scarp degradation modeling. Depending upon the desired photographic resolution and the platform/payload flown, aerial photos are typically acquired at altitudes of 40 - 100 meters above the ground surface. In all cases, high-precision ground control points are key for accurate (and repeatable) orientation - relying on low-precision GPS coordinates (whether on the ground or geotags in the aerial photos) typically results in substantial rotations (tilt) of the reference frame. Using common ground control points between repeat surveys results in matching point clouds with RMS residuals better than 10 cm. In arid regions, the point cloud is used to assess lava flow surface roughness using multi-scale measurements of point cloud dimensionality. For the landslide study, the point cloud provides a basis for assessing possible displacements. In addition, the high resolution orthophotos facilitate mapping of fractures and their growth. For neotectonic applications, we compare fault scarp modeling results from UAV-derived point clouds versus field-based surveys (kinematic GPS and electronic distance measurements). In summary, there is a wide ranging toolbox of low-altitude aerial platforms becoming available for field geoscientists. In many instances, these tools will present convenience and reduced cost compared with the effort and expense to contract acquisitions of aerial imagery.

The application of multi-baseline digital close-range photogrammetry in three-dimensional imaging and measurement of dental casts

PubMed Central

Li, Zan; Liu, Shan; Tan, Minmin; Song, Jinlin

2017-01-01

Objective To explore a new technique for reconstructing and measuring three-dimensional (3D) models of orthodontic plaster casts using multi-baseline digital close-range photogrammetry (MBDCRP) with a single-lens reflex camera. Study design Thirty sets of orthodontic plaster casts that do not exhibit severe horizontal overlap (>2 mm) between any two teeth were recorded by a single-lens reflex camera with 72 pictures taken in different directions. The 3D models of these casts were reconstructed and measured using the open source software MeshLab. These parameters, including mesio-distal crown diameter, arch width, and arch perimeter, were recorded six times on both the 3D digital models and on plaster casts by two examiners. Statistical analysis was carried out using the Bland–Altman method to measure agreement between the novel method and the traditional calliper method by calculating the differences between mean values. Results The average differences between the measurements of the photogrammetric 3D models and the plaster casts were 0.011–0.402mm. The mean differences between measurements obtained by the photogrammetric 3D models and the dental casts were not significant except for the lower arch perimeter (P>0.05), and all the differences were regarded as clinically acceptable (<0.5 mm). Conclusions Measurements obtained by MBDCRP are compared well with those obtained from plaster casts, indicating that MBDCRP is an alternate way to store and measure dental plaster casts without severe horizontal overlap between any two teeth. PMID:28640827

Heterodyne range imaging as an alternative to photogrammetry

NASA Astrophysics Data System (ADS)

Dorrington, Adrian; Cree, Michael; Carnegie, Dale; Payne, Andrew; Conroy, Richard

2007-01-01

Solid-state full-field range imaging technology, capable of determining the distance to objects in a scene simultaneously for every pixel in an image, has recently achieved sub-millimeter distance measurement precision. With this level of precision, it is becoming practical to use this technology for high precision three-dimensional metrology applications. Compared to photogrammetry, range imaging has the advantages of requiring only one viewing angle, a relatively short measurement time, and simplistic fast data processing. In this paper we fist review the range imaging technology, then describe an experiment comparing both photogrammetric and range imaging measurements of a calibration block with attached retro-reflective targets. The results show that the range imaging approach exhibits errors of approximately 0.5 mm in-plane and almost 5 mm out-of-plane; however, these errors appear to be mostly systematic. We then proceed to examine the physical nature and characteristics of the image ranging technology and discuss the possible causes of these systematic errors. Also discussed is the potential for further system characterization and calibration to compensate for the range determination and other errors, which could possibly lead to three-dimensional measurement precision approaching that of photogrammetry.

Obtaining Approximate Values of Exterior Orientation Elements of Multi-Intersection Images Using Particle Swarm Optimization

NASA Astrophysics Data System (ADS)

Li, X.; Li, S. W.

2012-07-01

In this paper, an efficient global optimization algorithm in the field of artificial intelligence, named Particle Swarm Optimization (PSO), is introduced into close range photogrammetric data processing. PSO can be applied to obtain the approximate values of exterior orientation elements under the condition that multi-intersection photography and a small portable plane control frame are used. PSO, put forward by an American social psychologist J. Kennedy and an electrical engineer R.C. Eberhart, is a stochastic global optimization method based on swarm intelligence, which was inspired by social behavior of bird flocking or fish schooling. The strategy of obtaining the approximate values of exterior orientation elements using PSO is as follows: in terms of image coordinate observed values and space coordinates of few control points, the equations of calculating the image coordinate residual errors can be given. The sum of absolute value of each image coordinate is minimized to be the objective function. The difference between image coordinate observed value and the image coordinate computed through collinear condition equation is defined as the image coordinate residual error. Firstly a gross area of exterior orientation elements is given, and then the adjustment of other parameters is made to get the particles fly in the gross area. After iterative computation for certain times, the satisfied approximate values of exterior orientation elements are obtained. By doing so, the procedures like positioning and measuring space control points in close range photogrammetry can be avoided. Obviously, this method can improve the surveying efficiency greatly and at the same time can decrease the surveying cost. And during such a process, only one small portable control frame with a couple of control points is employed, and there are no strict requirements for the space distribution of control points. In order to verify the effectiveness of this algorithm, two experiments are carried out. In the first experiment, images of a standard grid board are taken according to multi-intersection photography using digital camera. Three points or six points which are located on the left-down corner of the standard grid are regarded as control points respectively, and the exterior orientation elements of each image are computed through PSO, and compared with these elements computed through bundle adjustment. In the second experiment, the exterior orientation elements obtained from the first experiment are used as approximate values in bundle adjustment and then the space coordinates of other grid points on the board can be computed. The coordinate difference of grid points between these computed space coordinates and their known coordinates can be used to compute the accuracy. The point accuracy computed in above experiments are ±0.76mm and ±0.43mm respectively. The above experiments prove the effectiveness of PSO used in close range photogrammetry to compute approximate values of exterior orientation elements, and the algorithm can meet the requirement of higher accuracy. In short, PSO can get better results in a faster, cheaper way compared with other surveying methods in close range photogrammetry.

Rapid estimation of frequency response functions by close-range photogrammetry

NASA Technical Reports Server (NTRS)

Tripp, J. S.

1985-01-01

The accuracy of a rapid method which estimates the frequency response function from stereoscopic dynamic data is computed. It is shown that reversal of the order of the operations of coordinate transformation and Fourier transformation, which provides a significant increase in computational speed, introduces error. A portion of the error, proportional to the perturbation components normal to the camera focal planes, cannot be eliminated. The remaining error may be eliminated by proper scaling of frequency data prior to coordinate transformation. Methods are developed for least squares estimation of the full 3x3 frequency response matrix for a three dimensional structure.

NASA programs in advanced sensors and measurement technology for aeronautical applications

NASA Astrophysics Data System (ADS)

Conway, Bruce A.

NASA involvement in the development, implementation, and experimental use of advanced aeronautical sensors and measurement technologies is presently discussed within the framework of specific NASA research centers' activities. The technology thrusts are in the fields of high temperature strain gages and microphones, laser light-sheet flow visualization, LTA, LDV, and LDA, tunable laser-based aviation meteorology, and fiber-optic CARS measurements. IR thermography and close-range photogrammetry are undergoing substantial updating and application. It is expected that 'smart' sensors will be increasingly widely used, especially in conjunction with smart structures in aircraft and spacecraft.

Dot-Projection Photogrammetry and Videogrammetry of Gossamer Space Structures

NASA Technical Reports Server (NTRS)

Pappa, Richard S.; Black, Jonathan T.; Blandino, Joseph R.; Jones, Thomas W.; Danehy, Paul M.; Dorrington, Adrian A.

2003-01-01

This paper documents the technique of using hundreds or thousands of projected dots of light as targets for photogrammetry and videogrammetry of gossamer space structures. Photogrammetry calculates the three-dimensional coordinates of each target on the structure, and videogrammetry tracks the coordinates versus time. Gossamer structures characteristically contain large areas of delicate, thin-film membranes. Examples include solar sails, large antennas, inflatable solar arrays, solar power concentrators and transmitters, sun shields, and planetary balloons and habitats. Using projected-dot targets avoids the unwanted mass, stiffness, and installation costs of traditional retroreflective adhesive targets. Four laboratory applications are covered that demonstrate the practical effectiveness of white-light dot projection for both static-shape and dynamic measurement of reflective and diffuse surfaces, respectively. Comparisons are made between dot-projection videogrammetry and traditional laser vibrometry for membrane vibration measurements. The paper closes by introducing a promising extension of existing techniques using a novel laser-induced fluorescence approach.

Virtual 3d City Modeling: Techniques and Applications

NASA Astrophysics Data System (ADS)

Singh, S. P.; Jain, K.; Mandla, V. R.

2013-08-01

3D city model is a digital representation of the Earth's surface and it's related objects such as Building, Tree, Vegetation, and some manmade feature belonging to urban area. There are various terms used for 3D city models such as "Cybertown", "Cybercity", "Virtual City", or "Digital City". 3D city models are basically a computerized or digital model of a city contains the graphic representation of buildings and other objects in 2.5 or 3D. Generally three main Geomatics approach are using for Virtual 3-D City models generation, in first approach, researcher are using Conventional techniques such as Vector Map data, DEM, Aerial images, second approach are based on High resolution satellite images with LASER scanning, In third method, many researcher are using Terrestrial images by using Close Range Photogrammetry with DSM & Texture mapping. We start this paper from the introduction of various Geomatics techniques for 3D City modeling. These techniques divided in to two main categories: one is based on Automation (Automatic, Semi-automatic and Manual methods), and another is Based on Data input techniques (one is Photogrammetry, another is Laser Techniques). After details study of this, finally in short, we are trying to give the conclusions of this study. In the last, we are trying to give the conclusions of this research paper and also giving a short view for justification and analysis, and present trend for 3D City modeling. This paper gives an overview about the Techniques related with "Generation of Virtual 3-D City models using Geomatics Techniques" and the Applications of Virtual 3D City models. Photogrammetry, (Close range, Aerial, Satellite), Lasergrammetry, GPS, or combination of these modern Geomatics techniques play a major role to create a virtual 3-D City model. Each and every techniques and method has some advantages and some drawbacks. Point cloud model is a modern trend for virtual 3-D city model. Photo-realistic, Scalable, Geo-referenced virtual 3-D City model is a very useful for various kinds of applications such as for planning in Navigation, Tourism, Disasters Management, Transportations, Municipality, Urban Environmental Managements and Real-estate industry. So the Construction of Virtual 3-D city models is a most interesting research topic in recent years.

Using mid-range laser scanners to digitize cultural-heritage sites.

PubMed

Spring, Adam P; Peters, Caradoc; Minns, Tom

2010-01-01

Here, we explore new, more accessible ways of modeling 3D data sets that both professionals and amateurs can employ in areas such as architecture, forensics, geotechnics, cultural heritage, and even hobbyist modeling. To support our arguments, we present images from a recent case study in digital preservation of cultural heritage using a mid-range laser scanner. Our appreciation of the increasing variety of methods for capturing 3D spatial data inspired our research. Available methods include photogrammetry, airborne lidar, sonar, total stations (a combined electronic and optical survey instrument), and midand close-range scanning.1 They all can produce point clouds of varying density. In our case study, the point cloud produced by a mid-range scanner demonstrates how open source software can make modeling and disseminating data easier. Normally, researchers would model this data using expensive specialized software, and the data wouldn't extend beyond the laser-scanning community.

Comparing and integrating multiple data source for 3D surface reconstruction of Alpine Glaciers

NASA Astrophysics Data System (ADS)

Scaioni, Marco; Fugazza, Davide; Diolaiuti, Guglielmina Adele; Cernuschi, Massimo; Corti, Manuel

2017-04-01

Alpine glaciers are generally undergoing a fast and complex process leading to the reduction of the ice mass. Monitoring this process from a quantitative and qualitative point-of-view is of great importance for understanding the related dynamics and to apply proper numerical models. While the analysis of archive maps, medium resolution satellite images and DEM's may provide an overview of the long-term processes, the application of close-range sensing techniques offers the unprecedented opportunity to operate a 4D reconstruction of the glacier geometry. Terrestrial sensors technologies (Long and Very-long Range TLS and SfM Photogrammetry) integrated to UAV Photogrammetry may offer a complete view of the dynamical evolution of a glacier, reaching a high spatial and temporal resolution. Up until today, not many cases exist where a long-term archive of 4D high-resolution data has been established, limiting the chance to understand and to model the undergoing physical processes. The goal of the research presented here is to collect a set of multi-temporal data sets of the lower part of the Forni Glacier, in the National Stelvio Park, Italy. The first data acquisition campaign was carried out during August 2016, to be followed on yearly regular-basis. This will give the researchers the opportunity to analyse 4D data describing in detail the disruption of the glacier and its dramatic retreat. These data sets could be compared to DEM's acquired in the past by using UAV-Photogrammetry (2014) and traditional stereo-photogrammetry (2007). In addition, the presence of additional hydrological and meteorological data can be exploited in the analyses. The first data acquisition campaign has also given the opportunity to investigate the data acquisition methodology. The UAV flight has revealed to output a complete overview of the glacier surface in terms of DEM and orthophoto. Thanks to the photogrammetric process and the use of seven GNSS-GCPs, a high resolution has been obtained (about 102 pts/m2). The presence of vertical and sub-vertical surfaces has motivated the use of terrestrial sensors. The integration of sensors from ground and from drones has allowed to better describe some local physical processes (i.e., opening of crevasses, ice tunnelling, local collapses) that are giving an impressive contribution to the loss of ice bulk. This processes require a detail 3D modelling to be investigated, calling for the use of sensors able to reconstruct also the vertical and sub-vertical faces, thus using a ground-based standpoint. To this purpose, the adoption of SfM-Photogrammetry has yielded results comparable to the ones achieved using a long-range TLS Riegl LMS-Z420i, which can be assumed as benchmarking for accuracy assessment, but being more cumbersome and difficult to be operated in the glacier area. The measurement of GCPs for the terrestrial photogrammetric project reveal to be a complex task, involving the need of a total station. For this reason, the integration of GNSS and cameras will be developed for the future measurement sessions. The effect of block geometry on the final output has also been investigated for SfM-Photogrammetry, considering the severe limitations implied in the Alpine environment.

Acquisition and Processing Protocols for Uav Images: 3d Modeling of Historical Buildings Using Photogrammetry

NASA Astrophysics Data System (ADS)

Murtiyoso, A.; Koehl, M.; Grussenmeyer, P.; Freville, T.

2017-08-01

Photogrammetry has seen an increase in the use of UAVs (Unmanned Aerial Vehicles) for both large and smaller scale cartography. The use of UAVs is also advantageous because it may be used for tasks requiring quick response, including in the case of the inspection and monitoring of buildings. The objective of the project is to study the acquisition and processing protocols which exist in the literature and to adapt them for UAV projects. This implies a study on the calibration of the sensors, flight planning, comparison of software solutions, data management, and analysis on the different products of a UAV project. Two historical buildings of the city of Strasbourg were used as case studies: a part of the Rohan Palace façade and the St-Pierre-le-Jeune Catholic church. In addition, a preliminary test was performed on the Josephine Pavilion. Two UAVs were used in this research; namely the Sensefly Albris and the DJI Phantom 3 Professional. The experiments have shown that the calibration parameters tend to be unstable for small sensors. Furthermore, the dense matching of images remains a particular problem to address in a close range photogrammetry project, more so in the presence of noise on the images. Data management in cases where the number of images is high is also very important. The UAV is nevertheless a suitable solution for the surveying and recording of historical buildings because it is able to take images from points of view which are normally inaccessible to classical terrestrial techniques.

D Digitization of AN Heritage Masterpiece - a Critical Analysis on Quality Assessment

NASA Astrophysics Data System (ADS)

Menna, F.; Nocerino, E.; Remondino, F.; Dellepiane, M.; Callieri, M.; Scopigno, R.

2016-06-01

Despite being perceived as interchangeable when properly applied, close-range photogrammetry and range imaging have both their pros and limitations that can be overcome using suitable procedures. Even if the two techniques have been frequently cross-compared, critical analysis discussing all sub-phases of a complex digitization project are quite rare. Comparisons taking into account the digitization of a cultural masterpiece, such as the Etruscan Sarcophagus of the Spouses (Figure 1) discussed in this paper, are even less common. The final 3D model of the Sarcophagus shows impressive spatial and texture resolution, in the order of tenths of millimetre for both digitization techniques, making it a large 3D digital model even though the physical size of the artwork is quite limited. The paper presents the survey of the Sarcophagus, a late 6th century BC Etruscan anthropoid Sarcophagus. Photogrammetry and laser scanning were used for its 3D digitization in two different times only few days apart from each other. The very short time available for the digitization was a crucial constraint for the surveying operations (due to constraints imposed us by the museum curators). Despite very high-resolution and detailed 3D models have been produced, a metric comparison between the two models shows intrinsic limitations of each technique that should be overcome through suitable onsite metric verification procedures as well as a proper processing workflow.

A combined stereo-photogrammetry and underwater-video system to study group composition of dolphins

NASA Astrophysics Data System (ADS)

Bräger, S.; Chong, A.; Dawson, S.; Slooten, E.; Würsig, B.

1999-11-01

One reason for the paucity of knowledge of dolphin social structure is the difficulty of measuring individual dolphins. In Hector's dolphins, Cephalorhynchus hectori, total body length is a function of age, and sex can be determined by individual colouration pattern. We developed a novel system combining stereo-photogrammetry and underwater-video to record dolphin group composition. The system consists of two downward-looking single-lens-reflex (SLR) cameras and a Hi8 video camera in an underwater housing mounted on a small boat. Bow-riding Hector's dolphins were photographed and video-taped at close range in coastal waters around the South Island of New Zealand. Three-dimensional, stereoscopic measurements of the distance between the blowhole and the anterior margin of the dorsal fin (BH-DF) were calibrated by a suspended frame with reference points. Growth functions derived from measurements of 53 dead Hector's dolphins (29 female : 24 male) provided the necessary reference data. For the analysis, the measurements were synchronised with corresponding underwater-video of the genital area. A total of 27 successful measurements (8 with corresponding sex) were obtained, showing how this new system promises to be potentially useful for cetacean studies.

Four-dimensional reconstruction of cultural heritage sites based on photogrammetry and clustering

NASA Astrophysics Data System (ADS)

Voulodimos, Athanasios; Doulamis, Nikolaos; Fritsch, Dieter; Makantasis, Konstantinos; Doulamis, Anastasios; Klein, Michael

2017-01-01

A system designed and developed for the three-dimensional (3-D) reconstruction of cultural heritage (CH) assets is presented. Two basic approaches are presented. The first one, resulting in an "approximate" 3-D model, uses images retrieved in online multimedia collections; it employs a clustering-based technique to perform content-based filtering and eliminate outliers that significantly reduce the performance of 3-D reconstruction frameworks. The second one is based on input image data acquired through terrestrial laser scanning, as well as close range and airborne photogrammetry; it follows a sophisticated multistep strategy, which leads to a "precise" 3-D model. Furthermore, the concept of change history maps is proposed to address the computational limitations involved in four-dimensional (4-D) modeling, i.e., capturing 3-D models of a CH landmark or site at different time instances. The system also comprises a presentation viewer, which manages the display of the multifaceted CH content collected and created. The described methods have been successfully applied and evaluated in challenging real-world scenarios, including the 4-D reconstruction of the historic Market Square of the German city of Calw in the context of the 4-D-CH-World EU project.

Measurement of Flat Slab Deformations by the Multi-Image Photogrammetry Method

NASA Astrophysics Data System (ADS)

Marčiš, Marián; Fraštia, Marek; Augustín, Tomáš

2017-12-01

The use of photogrammetry during load tests of building components is a common practise all over the world. It is very effective thanks to its contactless approach, 3D measurement, fast data collection, and partial or full automation of image processing; it can deliver very accurate results. Multi-image convergent photogrammetry supported by artificial coded targets is the most accurate photogrammetric method when the targets are detected in an image with a higher degree of accuracy than a 0.1 pixel. It is possible to achieve an accuracy of 0.03 mm for all the points measured on the object observed if the camera is close enough to the object, and the positions of the camera and the number of shots are precisely planned. This contribution deals with the design of a special hanging frame for a DSLR camera used during the photogrammetric measurement of the deformation of flat concrete slab. The results of the photogrammetric measurements are compared to the results from traditional contact measurement techniques during load tests.

SU-E-T-754: Three-Dimensional Patient Modeling Using Photogrammetry for Collision Avoidance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popple, R; Cardan, R

2015-06-15

Purpose: To evaluate photogrammetry for creating a three-dimensional patient model. Methods: A mannequin was configured on the couch of a CT scanner to simulate a patient setup using an indexed positioning device. A CT fiducial was placed on the indexed CT table-overlay at the reference index position. Two dimensional photogrammetry targets were placed on the table in known positions. A digital SLR camera was used to obtain 27 images from different positions around the CT table. The images were imported into a commercial photogrammetry package and a 3D model constructed. Each photogrammetry target was identified on 2 to 5 images.more » The CT DICOM metadata and the position of the CT fiducial were used to calculate the coordinates of the photogrammetry targets in the CT image frame of reference. The coordinates were transferred to the photogrammetry software to orient the 3D model. The mannequin setup was transferred to the treatment couch of a linear accelerator and positioned at isocenter using in-room lasers. The treatment couch coordinates were noted and compared with prediction. The collision free regions were measured over the full range of gantry and table motion and were compared with predictions obtained using a general purpose polygon interference algorithm. Results: The reconstructed 3D model consisted of 180000 triangles. The difference between the predicted and measured couch positions were 5 mm, 1 mm, and 1 mm for longitudinal, lateral, and vertical, respectively. The collision prediction tested 64620 gantry table combinations in 11.1 seconds. The accuracy was 96.5%, with false positive and negative results occurring at the boundaries of the collision space. Conclusion: Photogrammetry can be used as a tool for collision avoidance during treatment planning. The results indicate that a buffer zone is necessary to avoid false negatives at the boundary of the collision-free zone. Testing with human patients is underway. Research partially supported by a grant from Varian Medical Systems.« less

Learning Photogrammetry with Interactive Software Tool PhoX

NASA Astrophysics Data System (ADS)

Luhmann, T.

2016-06-01

Photogrammetry is a complex topic in high-level university teaching, especially in the fields of geodesy, geoinformatics and metrology where high quality results are demanded. In addition, more and more black-box solutions for 3D image processing and point cloud generation are available that generate nice results easily, e.g. by structure-from-motion approaches. Within this context, the classical approach of teaching photogrammetry (e.g. focusing on aerial stereophotogrammetry) has to be reformed in order to educate students and professionals with new topics and provide them with more information behind the scene. Since around 20 years photogrammetry courses at the Jade University of Applied Sciences in Oldenburg, Germany, include the use of digital photogrammetry software that provide individual exercises, deep analysis of calculation results and a wide range of visualization tools for almost all standard tasks in photogrammetry. During the last years the software package PhoX has been developed that is part of a new didactic concept in photogrammetry and related subjects. It also serves as analysis tool in recent research projects. PhoX consists of a project-oriented data structure for images, image data, measured points and features and 3D objects. It allows for almost all basic photogrammetric measurement tools, image processing, calculation methods, graphical analysis functions, simulations and much more. Students use the program in order to conduct predefined exercises where they have the opportunity to analyse results in a high level of detail. This includes the analysis of statistical quality parameters but also the meaning of transformation parameters, rotation matrices, calibration and orientation data. As one specific advantage, PhoX allows for the interactive modification of single parameters and the direct view of the resulting effect in image or object space.

Three-dimensional imaging of hold baggage for airport security

NASA Astrophysics Data System (ADS)

Kolokytha, S.; Speller, R.; Robson, S.

2014-06-01

This study describes a cost-effective check-in baggage screening system, based on "on-belt tomosynthesis" (ObT) and close-range photogrammetry, that is designed to address the limitations of the most common system used, conventional projection radiography. The latter's limitations can lead to loss of information and an increase in baggage handling time, as baggage is manually searched or screened with more advanced systems. This project proposes a system that overcomes such limitations creating a cost-effective automated pseudo-3D imaging system, by combining x-ray and optical imaging to form digital tomograms. Tomographic reconstruction requires a knowledge of the change in geometry between multiple x-ray views of a common object. This is uniquely achieved using a close range photogrammetric system based on a small network of web-cameras. This paper presents the recent developments of the ObT system and describes recent findings of the photogrammetric system implementation. Based on these positive results, future work on the advancement of the ObT system as a cost-effective pseudo-3D imaging of hold baggage for airport security is proposed.

Application of Ruze Equation for Inflatable Aperture Antennas

NASA Technical Reports Server (NTRS)

Welch, Bryan W.

2008-01-01

Inflatable aperture reflector antennas are an emerging technology that NASA is investigating for potential uses in science and exploration missions. As inflatable aperture antennas have not been proven fully qualified for space missions, they must be characterized properly so that the behavior of the antennas can be known in advance. To properly characterize the inflatable aperture antenna, testing must be performed in a relevant environment, such as a vacuum chamber. Since the capability of having a radiofrequency (RF) test facility inside a vacuum chamber did not exist at NASA Glenn Research Center, a different methodology had to be utilized. The proposal to test an inflatable aperture antenna in a vacuum chamber entailed performing a photogrammetry study of the antenna surface by using laser ranging measurements. A root-mean-square (rms) error term was derived from the photogrammetry study to calculate the antenna surface loss as described by the Ruze equation. However, initial testing showed that problems existed in using the Ruze equation to calculate the loss due to errors on the antenna surface. This study utilized RF measurements obtained in a near-field antenna range and photogrammetry data taken from a laser range scanner to compare the expected performance of the test antenna (via the Ruze equation) with the actual RF patterns and directivity measurements. Results showed that the Ruze equation overstated the degradation in the directivity calculation. Therefore, when the photogrammetry study is performed on the test antennas in the vacuum chamber, a more complex equation must be used in light of the fact that the Ruze theory overstates the loss in directivity for inflatable aperture reflector antennas.

Near instantaneous production of digital terrain models in the field using smartphone and Structure-from-Motion photogrammetry

NASA Astrophysics Data System (ADS)

Micheletti, Natan; Chandler, Jim; Lane, Stuart

2013-04-01

Whilst high-resolution topographic and terrain data is essential in many geoscience applications, its acquisition has traditionally required either specific expertise (e.g. applications of photogrammetry) or expensive equipment (e.g. ground-based laser altimetric systems). Recent work in geomorphology (e.g. James and Robson, 2012; Carbonneau et al., 2012) has demonstrated the potential of Structure-from-Motion photogrammetry as a low cost, low expertise alternative for Digital Elevation Model (DEM) generation. These methods have geomorphological appeal because the more sophisticated image matching approaches remove many of the geometrical constraints associated with image acquisition: traditionally, vertical and "normal" image pairs acquired with a metric camera. This increases both the number of potential applications and the efficacy of image acquisition in the field. It also allows for genuine 3D (where the same (x,y) can have multiple z values) rather than 2.5D (where each (x,y) must have a unique z value) representation of the terrain surface. In this paper, we progress this technology further, by testing what can be acquired using hand-held smartphone technology, where the acquired images can be uploaded in the field to Open Source technology freely available to the research community. This is achieved by evaluating the quality of DEMs generated with a fully automated, open-source, Structure-from-Motion package and a smartphone (Apple Iphone 4) integrated camera (5 megapixels) using terrestrial laser scanning (TLS) data as benchmark. To allow a more objective assessment, it is necessary to compare both device and package with traditional approaches. Accordingly, we compare the error in the smartphone DEMs with the errors associated with data derived using a 16.2 megapixel digital camera and processed using the more traditional, commercial, close-range and semi-automated software PhotoModeler. Results demonstrate that centimeter precision DTMs can be achieved at close range, using a smartphone camera and a fully automated package, here illustrated for river bank survey. Results improve to sub-centimeter precision with either higher resolution images or by applying specific post-processing techniques to the smartphone DEMs. Extension to the survey of an entire Alpine alluvial fan system shows that the degradation of precision scales linearly with image scale, but that the quality: maintains a good level of precision; and is influenced equally with the difficulties of separating vegetation and sediment cover, typical of laser scanning systems.

High resolution mapping of riffle-pool dynamics based on ADCP and close-range remote sensing data

NASA Astrophysics Data System (ADS)

Salmela, Jouni; Kasvi, Elina; Alho, Petteri

2017-04-01

Present development of mobile laser scanning (MLS) and close-range photogrammetry with unmanned aerial vehicle (UAV) enable us to create seamless digital elevation models (DEMs) of the riverine environment. Remote-controlled flow measurement platforms have also improved spatio-temporal resolution of the flow field data. In this study, acoustic Doppler current profiler (ADCP) attached to remote-controlled mini-boat, UAV-based bathymetry and MLS techniques were utilized to create the high-resolution DEMs of the river channel. These high-resolution measurements can be used in many fluvial applications such as computational fluid dynamics, channel change detection, habitat mapping or hydro-electric power plant planning. In this study we aim: 1) to analyze morphological changes of river channel especially riffle and pool formations based on fine-scale DEMs and ADCP measurements, 2) to analyze flow fields and their effect on morphological changes. The interest was mainly focused on reach-scale riffle-pool dynamics within two-year period of 2013 and 2014. The study was performed in sub-arctic meandering Pulmankijoki River located in Northern Finland. The river itself has shallow and clear water and sandy bed sediment. Discharge remains typically below 10 m3s-1 most of the year but during snow melt period in spring the discharge may exceed 70 m3s-1. We compared DEMs and ADCP measurements to understand both magnitude and spatio-temporal change of the river bed. Models were accurate enough to study bed form changes and locations and persistence of riffles and pools. We analyzed their locations with relation to flow during the peak and low discharge. Our demonstrated method has improved significantly spatio-temporal resolution of riverine DEMs compared to other cross-sectional and photogrammetry based models. Together with flow field measurements we gained better understanding of riverbed-water interaction

Measurement of 3-D Vibrational Motion by Dynamic Photogrammetry Using Least-Square Image Matching for Sub-Pixel Targeting to Improve Accuracy.

PubMed

Lee, Hyoseong; Rhee, Huinam; Oh, Jae Hong; Park, Jin Ho

2016-03-11

This paper deals with an improved methodology to measure three-dimensional dynamic displacements of a structure by digital close-range photogrammetry. A series of stereo images of a vibrating structure installed with targets are taken at specified intervals by using two daily-use cameras. A new methodology is proposed to accurately trace the spatial displacement of each target in three-dimensional space. This method combines the correlation and the least-square image matching so that the sub-pixel targeting can be obtained to increase the measurement accuracy. Collinearity and space resection theory are used to determine the interior and exterior orientation parameters. To verify the proposed method, experiments have been performed to measure displacements of a cantilevered beam excited by an electrodynamic shaker, which is vibrating in a complex configuration with mixed bending and torsional motions simultaneously with multiple frequencies. The results by the present method showed good agreement with the measurement by two laser displacement sensors. The proposed methodology only requires inexpensive daily-use cameras, and can remotely detect the dynamic displacement of a structure vibrating in a complex three-dimensional defection shape up to sub-pixel accuracy. It has abundant potential applications to various fields, e.g., remote vibration monitoring of an inaccessible or dangerous facility.

Measurement of 3-D Vibrational Motion by Dynamic Photogrammetry Using Least-Square Image Matching for Sub-Pixel Targeting to Improve Accuracy

PubMed Central

Lee, Hyoseong; Rhee, Huinam; Oh, Jae Hong; Park, Jin Ho

2016-01-01

This paper deals with an improved methodology to measure three-dimensional dynamic displacements of a structure by digital close-range photogrammetry. A series of stereo images of a vibrating structure installed with targets are taken at specified intervals by using two daily-use cameras. A new methodology is proposed to accurately trace the spatial displacement of each target in three-dimensional space. This method combines the correlation and the least-square image matching so that the sub-pixel targeting can be obtained to increase the measurement accuracy. Collinearity and space resection theory are used to determine the interior and exterior orientation parameters. To verify the proposed method, experiments have been performed to measure displacements of a cantilevered beam excited by an electrodynamic shaker, which is vibrating in a complex configuration with mixed bending and torsional motions simultaneously with multiple frequencies. The results by the present method showed good agreement with the measurement by two laser displacement sensors. The proposed methodology only requires inexpensive daily-use cameras, and can remotely detect the dynamic displacement of a structure vibrating in a complex three-dimensional defection shape up to sub-pixel accuracy. It has abundant potential applications to various fields, e.g., remote vibration monitoring of an inaccessible or dangerous facility. PMID:26978366

Reservoir analog studies using multimodel photogrammetry: A new tool for the petroleum industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dueholm, K.S.; Olsen, T.

1993-12-01

Attempts to increase the recovery from hydrocarbon reservoirs involve high-precision geological work. Siliciclastic depositional environments must be interpreted accurately and combined with an analysis of the three-dimensional shape of the sand bodies. An advanced photogrammetric method called multimodel stereo restitution is a potential new tool for the petroleum industry when outcrop investigations are necessary, such as in reservoir analog studies. The method is based on very simple field photography techniques, allowing the geologist to use his own standard small-frame camera. It can be applied to geological studies of virtually any scale, and outcrop mapping is significantly improved in detail, accuracy,more » and volume. The method is especially useful when investigating poorly accessible exposures on steep mountain faces and canyon walls. The use of multimodel photogrammetry is illustrated by a study of Upper Cretaceous deltaic sediments from the Atane Formation of West Greenland. Further potential applications of the method in petroleum explorations are discussed. True-scale mapping of lithologies in large continuous exposures can be used in understanding basin evolution and in seismic modeling. Close-range applications can be used when modeling fault geometries, and in studies of individual bed forms, clay laminae, cemented horizons, and diagenetic fronts.« less

Close-range airborne Structure-from-Motion Photogrammetry for high-resolution beach morphometric surveys: Examples from an embayed rotating beach

NASA Astrophysics Data System (ADS)

Brunier, Guillaume; Fleury, Jules; Anthony, Edward J.; Gardel, Antoine; Dussouillez, Philippe

2016-05-01

The field of photogrammetry has seen significant new developments essentially related to the emergence of new computer-based applications that have fostered the growth of the workflow technique called Structure-from-Motion (SfM). Low-cost, user-friendly SfM photogrammetry offers interesting new perspectives in coastal and other fields of geomorphology requiring high-resolution topographic data. The technique enables the construction of topographic products such as digital surface models (DSMs) and orthophotographs, and combines the advantages of the reproducibility of GPS surveys and the high density and accuracy of airborne LiDAR, but at very advantageous cost compared to the latter. Three SfM-based photogrammetric experiments were conducted on the embayed beach of Montjoly in Cayenne, French Guiana, between October 2013 and 2014, in order to map morphological changes and quantify sediment budgets. The beach is affected by a process of rotation induced by the alongshore migration of mud banks from the mouths of the Amazon River that generate spatial and temporal changes in wave refraction and incident wave angles, thus generating the reversals in longshore drift that characterise this process. Sub-vertical aerial photographs of the beach were acquired from a microlight aircraft that flew alongshore at low elevation (275 m). The flight plan included several parallel flight axes with an overlap of 85% between pictures in the lengthwise direction and 50% between paths. Targets of 40 × 40 cm, georeferenced by RTK-DGPS, were placed on the beach, spaced 100 m apart. These targets served in optimizing the model and in producing georeferenced 3D products. RTK-GPS measurements of random points and cross-shore profiles were used to validate the photogrammetry results and assess their accuracy. We produced dense point clouds with 150 to 200 points/m², from which we generated DSMs and orthophotos with respective resolutions of 10 cm and 5 cm. Compared to the GPS control points, we obtained a mean vertical accuracy less than ± 10 cm, with a maximum of 20 cm in marginal sectors with sparse vegetation and in the lower intertidal zone where water-saturated surfaces generated lower-resolution data as a result of a lack of coherence between photographs. The overall results show that SfM photogrammetry is a robust tool for beach morphological and sediment budget surveys. Our SfM workflow enabled the discrimination of beach surface features at a scale of a few tens of centimetres despite the low textural contrasts exhibited by the quartz beach sand and the relatively uniform upper beach topography, as well as the calculation of beach sediment budgets. 66,000 m³ of sand were removed from the northern sector of the beach, of which 22,000 m³ were transferred to the southern sector in the course of rotation. Finally, we briefly highlight: (1) the advantages of SfM photogrammetry compared to other high-resolution survey methods, (2) the advantages and disadvantages of, respectively, a microlight aircraft and an unmanned aerial vehicle (UAV) in undertaking SfM photogrammetry, and (3) areas of potential future improvement of the SfM workflow technique. These concern more extensive cross-shore deployment of ground control points to reduce possible tilt, and oblique cross-shore photography to improve parallax.

Thermal/vacuum measurements of the Herschel space telescope by close-range photogrammetry

NASA Astrophysics Data System (ADS)

Parian, J. Amiri; Cozzani, A.; Appolloni, M.; Casarosa, G.

2017-11-01

In the frame of the development of a videogrammetric system to be used in thermal vacuum chambers at the European Space Research and Technology Centre (ESTEC) and other sites across Europe, the design of a network using micro-cameras was specified by the European Space agency (ESA)-ESTEC. The selected test set-up is the photogrammetric test of the Herschel Satellite Flight Model in the ESTEC Large Space Simulator. The photogrammetric system will be used to verify the Herschel Telescope alignment and Telescope positioning with respect to the Cryostat Vacuum Vessel (CVV) inside the Large Space Simulator during Thermal-Vacuum/Thermal-Balance test phases. We designed a close-range photogrammetric network by heuristic simulation and a videogrammetric system with an overall accuracy of 1:100,000. A semi-automated image acquisition system, which is able to work at low temperatures (-170°C) in order to acquire images according to the designed network has been constructed by ESA-ESTEC. In this paper we will present the videogrammetric system and sub-systems and the results of real measurements with a representative setup similar to the set-up of Herschel spacecraft which was realized in ESTEC Test Centre.

Vexcel Spells Excellence for Earth and Space

NASA Technical Reports Server (NTRS)

2002-01-01

With assistance from Stennis Space Center, Vexcel was able to strengthen the properties of its Apex Ground Station(TM), an affordable, end-to-end system that comes complete with a tracking antenna that permits coverage within an approximate 2,000-kilometer radius of its location, a high speed direct-to-disk data acquisition system that can download information from virtually any satellite, and data processing software for virtually all synthetic aperture radar and optical satellite sensors. Vexcel is using an Apex system linked to the Terra satellite to help scientists and NASA personnel measure land and ocean surface temperatures, detect fires, monitor ocean color and currents, produce global vegetation maps and data, and assess cloud characteristics and aerosol concentrations. In addition, Vexcel is providing NASA with close-range photogrammetry software for the International Space Station. The technology, commercially available as FotoG(TM), was developed with SBIR funding and support from NASA's Jet Propulsion Laboratory. Commercially, FotoG is used for demanding projects taken on by engineering firms, nuclear power plants, oil refineries, and process facilities. A version of Vexcel's close-range photo measurement system was also used to create virtual 3-D backdrops for a high-tech science fiction film.

Calibration of the Nikon 200 for Close Range Photogrammetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheriff, Lassana; /City Coll., N.Y. /SLAC

2010-08-25

The overall objective of this project is to study the stability and reproducibility of the calibration parameters of the Nikon D200 camera with a Nikkor 20 mm lens for close-range photogrammetric surveys. The well known 'central perspective projection' model is used to determine the camera parameters for interior orientation. The Brown model extends it with the introduction of radial distortion and other less critical variables. The calibration process requires a dense network of targets to be photographed at different angles. For faster processing, reflective coded targets are chosen. Two scenarios have been used to check the reproducibility of the parameters.more » The first one is using a flat 2D wall with 141 coded targets and 12 custom targets that were previously measured with a laser tracker. The second one is a 3D Unistrut structure with a combination of coded targets and 3D reflective spheres. The study has shown that this setup is only stable during a short period of time. In conclusion, this camera is acceptable when calibrated before each use. Future work should include actual field tests and possible mechanical improvements, such as securing the lens to the camera body.« less

Experimental comparison of photogrammetry for additive manufactured parts with and without laser speckle projection

NASA Astrophysics Data System (ADS)

Sims-Waterhouse, D.; Bointon, P.; Piano, S.; Leach, R. K.

2017-06-01

In this paper we show that, by using a photogrammetry system with and without laser speckle, a large range of additive manufacturing (AM) parts with different geometries, materials and post-processing textures can be measured to high accuracy. AM test artefacts have been produced in three materials: polymer powder bed fusion (nylon-12), metal powder bed fusion (Ti-6Al-4V) and polymer material extrusion (ABS plastic). Each test artefact was then measured with the photogrammetry system in both normal and laser speckle projection modes and the resulting point clouds compared with the artefact CAD model. The results show that laser speckle projection can result in a reduction of the point cloud standard deviation from the CAD data of up to 101 μm. A complex relationship with surface texture, artefact geometry and the laser speckle projection is also observed and discussed.

Image-based surface reconstruction in geomorphometry - merits, limits and developments of a promising tool for geoscientists

NASA Astrophysics Data System (ADS)

Eltner, A.; Kaiser, A.; Castillo, C.; Rock, G.; Neugirg, F.; Abellan, A.

2015-12-01

Photogrammetry and geosciences are closely linked since the late 19th century. Today, a wide range of commercial and open-source software enable non-experts users to obtain high-quality 3-D datasets of the environment, which was formerly reserved to remote sensing experts, geodesists or owners of cost-intensive metric airborne imaging systems. Complex tridimensional geomorphological features can be easily reconstructed from images captured with consumer grade cameras. Furthermore, rapid developments in UAV technology allow for high quality aerial surveying and orthophotography generation at a relatively low-cost. The increasing computing capacities during the last decade, together with the development of high-performance digital sensors and the important software innovations developed by other fields of research (e.g. computer vision and visual perception) has extended the rigorous processing of stereoscopic image data to a 3-D point cloud generation from a series of non-calibrated images. Structure from motion methods offer algorithms, e.g. robust feature detectors like the scale-invariant feature transform for 2-D imagery, which allow for efficient and automatic orientation of large image sets without further data acquisition information. Nevertheless, the importance of carrying out correct fieldwork strategies, using proper camera settings, ground control points and ground truth for understanding the different sources of errors still need to be adapted in the common scientific practice. This review manuscript intends not only to summarize the present state of published research on structure-from-motion photogrammetry applications in geomorphometry, but also to give an overview of terms and fields of application, to quantify already achieved accuracies and used scales using different strategies, to evaluate possible stagnations of current developments and to identify key future challenges. It is our belief that the identification of common errors, "bad practices" and some other valuable information in already published articles, scientific reports and book chapters may help in guiding the future use of SfM photogrammetry in geosciences.

Comparisons of Simultaneously Acquired Airborne Sfm Photogrammetry and Lidar

NASA Astrophysics Data System (ADS)

Larsen, C. F.

2014-12-01

Digital elevation models (DEMs) created using images from a consumer DSLR camera are compared against simultaneously acquired LiDAR on a number of airborne mapping projects across Alaska, California and Utah. The aircraft used is a Cessna 180, and is equipped with the University of Alaska Geophysical Institute (UAF-GI) scanning airborne LiDAR system. This LiDAR is the same as described in Johnson et al, 2013, and is the principal instrument used for NASA's Operation IceBridge flights in Alaska. The system has been in extensive use since 2009, and is particularly well characterized with dozens of calibration flights and a careful program of boresight angle determination and monitoring. The UAF-GI LiDAR has a precision of +/- 8 cm and accuracy of +/- 15 cm. The photogrammetry DEM simultaneously acquired with the LiDAR relies on precise shutter timing using an event marker input to the IMU associated with the LiDAR system. The photo positions are derived from the fully coupled GPS/IMU processing, which samples at 100 Hz and is able to directly calculate the antenna to image plane offset displacements from the full orientation data. This use of the GPS/IMU solution means that both the LiDAR and Cessna 180 photogrammetry DEM share trajectory input data, however no orientation data nor ground control is used for the photorammetry processing. The photogrammetry DEMs are overlaid on the LiDAR point cloud and analyzed for horizontal shifts or warps relative to the LiDAR. No warping or horizontal shifts have been detectable for a number of photogrammetry DEMs. Vertical offsets range from +/- 30 cm, with a typical standard deviation about that mean of 10 cm or better. LiDAR and photogrammetry function inherently differently over trees and brush, and direct comparisons between the two methods show much larger differences over vegetated areas. Finally, the differences in flight patterns associated with the two methods will be discussed, highlighting the photogrammetry requirements for a well planned grid pattern and the effects of significant end lap and side lap in the imagery coverage.

Vertical Accuracy Evaluation of Aster GDEM2 Over a Mountainous Area Based on Uav Photogrammetry

NASA Astrophysics Data System (ADS)

Liang, Y.; Qu, Y.; Guo, D.; Cui, T.

2018-05-01

Global digital elevation models (GDEM) provide elementary information on heights of the Earth's surface and objects on the ground. GDEMs have become an important data source for a range of applications. The vertical accuracy of a GDEM is critical for its applications. Nowadays UAVs has been widely used for large-scale surveying and mapping. Compared with traditional surveying techniques, UAV photogrammetry are more convenient and more cost-effective. UAV photogrammetry produces the DEM of the survey area with high accuracy and high spatial resolution. As a result, DEMs resulted from UAV photogrammetry can be used for a more detailed and accurate evaluation of the GDEM product. This study investigates the vertical accuracy (in terms of elevation accuracy and systematic errors) of the ASTER GDEM Version 2 dataset over a complex terrain based on UAV photogrammetry. Experimental results show that the elevation errors of ASTER GDEM2 are in normal distribution and the systematic error is quite small. The accuracy of the ASTER GDEM2 coincides well with that reported by the ASTER validation team. The accuracy in the research area is negatively correlated to both the slope of the terrain and the number of stereo observations. This study also evaluates the vertical accuracy of the up-sampled ASTER GDEM2. Experimental results show that the accuracy of the up-sampled ASTER GDEM2 data in the research area is not significantly reduced by the complexity of the terrain. The fine-grained accuracy evaluation of the ASTER GDEM2 is informative for the GDEM-supported UAV photogrammetric applications.

Comparative study of cranial anthropometric measurement by traditional calipers to computed tomography and three-dimensional photogrammetry.

PubMed

Mendonca, Derick A; Naidoo, Sybill D; Skolnick, Gary; Skladman, Rachel; Woo, Albert S

2013-07-01

Craniofacial anthropometry by direct caliper measurements is a common method of quantifying the morphology of the cranial vault. New digital imaging modalities including computed tomography and three-dimensional photogrammetry are similarly being used to obtain craniofacial surface measurements. This study sought to compare the accuracy of anthropometric measurements obtained by calipers versus 2 methods of digital imaging.Standard anterior-posterior, biparietal, and cranial index measurements were directly obtained on 19 participants with an age range of 1 to 20 months. Computed tomographic scans and three-dimensional photographs were both obtained on each child within 2 weeks of the clinical examination. Two analysts measured the anterior-posterior and biparietal distances on the digital images. Measures of reliability and bias between the modalities were calculated and compared.Caliper measurements were found to underestimate the anterior-posterior and biparietal distances as compared with those of the computed tomography and the three-dimensional photogrammetry (P < 0.001). Cranial index measurements between the computed tomography and the calipers differed by up to 6%. The difference between the 2 modalities was statistically significant (P = 0.021). The biparietal and cranial index results were similar between the digital modalities, but the anterior-posterior measurement was greater with the three-dimensional photogrammetry (P = 0.002). The coefficients of variation for repeated measures based on the computed tomography and the three-dimensional photogrammetry were 0.008 and 0.007, respectively.In conclusion, measurements based on digital modalities are generally reliable and interchangeable. Caliper measurements lead to underestimation of anterior-posterior and biparietal values compared with digital imaging.

Automated landmark extraction for orthodontic measurement of faces using the 3-camera photogrammetry methodology.

PubMed

Deli, Roberto; Di Gioia, Eliana; Galantucci, Luigi Maria; Percoco, Gianluca

2010-01-01

To set up a three-dimensional photogrammetric scanning system for precise landmark measurements, without any physical contact, using a low-cost and noninvasive digital photogrammetric solution, for supporting several necessity in clinical orthodontics and/or surgery diagnosis. Thirty coded targets were directly applied onto the subject's face on the soft tissue landmarks, and then, 3 simultaneous photos were acquired using photogrammetry, at room light conditions. For comparison, a dummy head was digitized both with a photogrammetric technique and with the laser scanner Minolta Vivid 910i (Konica Minolta, Tokyo, Japan). The precise measurement of the landmarks is ranged between 0.017 and 0.029 mm. The system automatically measures spatial position of face landmarks, from which distances and angles can be obtained. The facial measurements were compared with those done using laser scanning and manual caliper. The adopted method gives higher precision than the others (0.022-mm mean value on points and 0.038-mm mean value on linear distances on a dummy head), is simple, and can be used easily as a standard routine. The study demonstrated the validity of photogrammetry for accurate digitization of human face landmarks. This research points out the potential of this low-cost photogrammetry approach for medical digitization.

Scattering from Rock and Rock Outcrops

DTIC Science & Technology

2014-09-30

orientations and size distributions reflect the internal fault organization of the bedrock. The plot in Fig. 3 displays experimentally determined PFA...mechanisms contributing could be scattering from small scale roughness combined with specular scattering from facets oriented close to normal incidence to...Larvik, Norway made with a stereo photogrammetry system. 7 IMPACT/APPLICATIONS The primary work completed over the course of this project

Open Pit Mine 3d Mapping by Tls and Digital Photogrammetry: 3d Model Update Thanks to a Slam Based Approach

NASA Astrophysics Data System (ADS)

Vassena, G.; Clerici, A.

2018-05-01

The state of the art of 3D surveying technologies, if correctly applied, allows to obtain 3D coloured models of large open pit mines using different technologies as terrestrial laser scanner (TLS), with images, combined with UAV based digital photogrammetry. GNSS and/or total station are also currently used to geo reference the model. The University of Brescia has been realised a project to map in 3D an open pit mine located in Botticino, a famous location of marble extraction close to Brescia in North Italy. Terrestrial Laser Scanner 3D point clouds combined with RGB images and digital photogrammetry from UAV have been used to map a large part of the cave. By rigorous and well know procedures a 3D point cloud and mesh model have been obtained using an easy and rigorous approach. After the description of the combined mapping process, the paper describes the innovative process proposed for the daily/weekly update of the model itself. To realize this task a SLAM technology approach is described, using an innovative approach based on an innovative instrument capable to run an automatic localization process and real time on the field change detection analysis.

Photogrammetry of the particle trajectories on DIPOLE WEST Shots 8, 9, 10, and 11. Volume III. Shot 8. Final report, 1 October--31 December 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dewey, J.M.; McMillin, D.J.; Trill, D.

1978-01-01

This volume describes the photogrammetry and analysis of the particle trajectories in blast waves produced by the simultaneous detonation of two spherical 1080-lb (490-kg) Pentolite charges (DIPOLE WEST Shot 8). One of the charges was positioned at a height of 25 feet above smooth ground, and the second charge 50 feet above the first. Photogrammetrical measurements were made of the trajectories of air particle flow tracers (smoke puffs), which had been placed in a vertical grid at heights ranging from 3 to 58 feet above the ground and at radial distances ranging from 25 to 140 feet from the verticalmore » axis through the charges. From the measured particle trajectories, calculations were made, as described in AD-A058 377. From the shock front times-of-arrival, calculations were made of the shock velocities and, in turn, the peak particle velocities, air densities and hydrostatic overpressure immediately behind each shock. Calculations were also made of the variation with time of the particle velocity, density, hydrostatic overpressure, dynamic pressure, and total pressure at several fixed points. Results, presented both graphically and in tables, are compared to results previously calculated for the same experiment using shock front photogrammetry.« less

An Automatic Image-Based Modelling Method Applied to Forensic Infography

PubMed Central

Zancajo-Blazquez, Sandra; Gonzalez-Aguilera, Diego; Gonzalez-Jorge, Higinio; Hernandez-Lopez, David

2015-01-01

This paper presents a new method based on 3D reconstruction from images that demonstrates the utility and integration of close-range photogrammetry and computer vision as an efficient alternative to modelling complex objects and scenarios of forensic infography. The results obtained confirm the validity of the method compared to other existing alternatives as it guarantees the following: (i) flexibility, permitting work with any type of camera (calibrated and non-calibrated, smartphone or tablet) and image (visible, infrared, thermal, etc.); (ii) automation, allowing the reconstruction of three-dimensional scenarios in the absence of manual intervention, and (iii) high quality results, sometimes providing higher resolution than modern laser scanning systems. As a result, each ocular inspection of a crime scene with any camera performed by the scientific police can be transformed into a scaled 3d model. PMID:25793628

In-Vacuum Photogrammetry of a 10-Meter Solar Sail

NASA Technical Reports Server (NTRS)

Meyer, Chris G.; Jones, Thomas W.; Lunsford, Charles B.; Pappa, Richard S.

2005-01-01

In July 2004, a 10-meter solar sail structure developed by L Garde, Inc. was tested in vacuum at the NASA Glenn 30-meter Plum Brook Space Power Facility in Sandusky, Ohio. The three main objections of the test were to demonstrate unattended deployment from a stowed configuration, to measure the deployed shape of the sail at both ambient and cryogenic room temperatures, and to measure the deployed structural dynamic characteristics (vibration modes). This paper summarizes the work conducted to fulfill the second test objective. The deployed shape was measured photogrammetrically in vacuum conditions with four 2-megapixel digital video cameras contained in custom made pressurized canisters. The canisters included high-intensity LED ring lights to illuminate a grid of retroreflective targets distributed on the solar sail. The test results closely matched pre-test photogrammetry numerical simulations and compare well with ABAQUS finite-element model predictions.

Photogrammetry: An available surface characterization tool for solar concentrators. Part 2: Assessment of surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shortis, M.; Johnston, G.

1997-11-01

In a previous paper, the results of photogrammetric measurements of a number of paraboloidal reflecting surfaces were presented. These results showed that photogrammetry can provide three-dimensional surface characterizations of such solar concentrators. The present paper describes the assessment of the quality of these surfaces as a derivation of the photogrammetrically produced surface coordinates. Statistical analysis of the z-coordinate distribution of errors indicates that these generally conform to a univariate Gaussian distribution, while the numerical assessment of the surface normal vectors on these surfaces indicates that the surface normal deviations appear to follow an approximately bivariate Gaussian distribution. Ray tracing ofmore » the measured surfaces to predict the expected flux distribution at the focal point of the 400 m{sup 2} dish show a close correlation with the videographically measured flux distribution at the focal point of the dish.« less

Integration of UAV photogrammetry and SPH modelling of fluids to study runoff on real terrains.

PubMed

Barreiro, Anxo; Domínguez, Jose M; C Crespo, Alejandro J; González-Jorge, Higinio; Roca, David; Gómez-Gesteira, Moncho

2014-01-01

Roads can experience runoff problems due to the intense rain discharge associated to severe storms. Two advanced tools are combined to analyse the interaction of complex water flows with real terrains. UAV (Unmanned Aerial Vehicle) photogrammetry is employed to obtain accurate topographic information on small areas, typically on the order of a few hectares. The Smoothed Particle Hydrodynamics (SPH) technique is applied by means of the DualSPHysics model to compute the trajectory of the water flow during extreme rain events. The use of engineering solutions to palliate flood events is also analysed. The study case simulates how the collected water can flow into a close road and how precautionary measures can be effective to drain water under extreme conditions. The amount of water arriving at the road is calculated under different protection scenarios and the efficiency of a ditch is observed to decrease when sedimentation reduces its depth.

Integration of UAV Photogrammetry and SPH Modelling of Fluids to Study Runoff on Real Terrains

PubMed Central

Barreiro, Anxo; Domínguez, Jose M.; C. Crespo, Alejandro J.; González-Jorge, Higinio; Roca, David; Gómez-Gesteira, Moncho

2014-01-01

Roads can experience runoff problems due to the intense rain discharge associated to severe storms. Two advanced tools are combined to analyse the interaction of complex water flows with real terrains. UAV (Unmanned Aerial Vehicle) photogrammetry is employed to obtain accurate topographic information on small areas, typically on the order of a few hectares. The Smoothed Particle Hydrodynamics (SPH) technique is applied by means of the DualSPHysics model to compute the trajectory of the water flow during extreme rain events. The use of engineering solutions to palliate flood events is also analysed. The study case simulates how the collected water can flow into a close road and how precautionary measures can be effective to drain water under extreme conditions. The amount of water arriving at the road is calculated under different protection scenarios and the efficiency of a ditch is observed to decrease when sedimentation reduces its depth. PMID:25372035

Analysis of Low-Light and Night-Time Stereo-Pair Images for Photogrammetric Reconstruction

NASA Astrophysics Data System (ADS)

Santise, M.; Thoeni, K.; Roncella, R.; Diotri, F.; Giacomini, A.

2018-05-01

Rockfalls and rockslides represent a significant risk to human lives and infrastructures because of the high levels of energy involved in the phenomena. Generally, these events occur in accordance to specific environmental conditions, such as temperature variations between day and night, that can contribute to the triggering of structural instabilities in the rock-wall and the detachment of blocks and debris. The monitoring and the geostructural characterization of the wall are required for reducing the potential hazard and to improve the management of the risk at the bottom of the slopes affected by such phenomena. In this context, close range photogrammetry is largely used for the monitoring of high-mountain terrains and rock walls in mine sites allowing for periodic survey of rockfalls and wall movements. This work focuses on the analysis of low-light and night-time images of a fixed-base stereo pair photogrammetry system. The aim is to study the reliability of the images acquired over the night to produce digital surface models (DSMs) for change detection. The images are captured by a high-sensitivity DLSR camera using various settings accounting for different values of ISO, aperture and time of exposure. For each acquisition, the DSM is compared to a photogrammetric reference model produced by images captured in optimal illumination conditions. Results show that, with high level of ISO and maintaining the same grade of aperture, extending the exposure time improves the quality of the point clouds in terms of completeness and accuracy of the photogrammetric models.

Simultaneous observations of ice motion, calving and seismicity on the Yahtse Glacier, Alaska. (Invited)

NASA Astrophysics Data System (ADS)

Larsen, C. F.; Bartholomaus, T. C.; O'Neel, S.; West, M. E.

2010-12-01

We observe ice motion, calving and seismicity simultaneously and with high-resolution on an advancing tidewater glacier in Icy Bay, Alaska. Icy Bay’s tidewater glaciers dominate regional glacier-generated seismicity in Alaska. Yahtse emanates from the St. Elias Range near the Bering-Bagley-Seward-Malaspina Icefield system, the most extensive glacier cover outside the polar regions. Rapid rates of change and fast flow (>16 m/d near the terminus) at Yahtse Glacier provide a direct analog to the disintegrating outlet systems in Greenland. Our field experiment co-locates GPS and seismometers on the surface of the glacier, with a greater network of bedrock seismometers surrounding the glacier. Time-lapse photogrammetry, fjord wave height sensors, and optical survey methods monitor iceberg calving and ice velocity near the terminus. This suite of geophysical instrumentation enables us to characterize glacier motion and geometry changes while concurrently listening for seismic energy release. We are performing a close examination of calving as a seismic source, and the associated mechanisms of energy transfer to seismic waves. Detailed observations of ice motion (GPS and optical surveying), glacier geometry and iceberg calving (direct observations and timelapse photogrammetry) have been made in concert with a passive seismic network. Combined, the observations form the basis of a rigorous analysis exploring the relationship between glacier-generated seismic events and motion, glacier-fiord interactions, calving and hydraulics. Our work is designed to demonstrate the applicability and utility of seismology to study the impact of climate forcing on calving glaciers.

Applications of Photogrammetry for Analysis of Forest Plantations. Preliminary study: Analysis of individual trees

NASA Astrophysics Data System (ADS)

Mora, R.; Barahona, A.; Aguilar, H.

2015-04-01

This paper presents a method for using high detail volumetric information, captured with a land based photogrammetric survey, to obtain information from individual trees. Applying LIDAR analysis techniques it is possible to measure diameter at breast height, height at first branch (commercial height), basal area and volume of an individual tree. Given this information it is possible to calculate how much of that tree can be exploited as wood. The main objective is to develop a methodology for successfully surveying one individual tree, capturing every side of the stem a using high resolution digital camera and reference marks with GPS coordinates. The process is executed for several individuals of two species present in the metropolitan area in San Jose, Costa Rica, Delonix regia (Bojer) Raf. and Tabebuia rosea (Bertol.) DC., each one with different height, stem shape and crown area. Using a photogrammetry suite all the pictures are aligned, geo-referenced and a dense point cloud is generated with enough detail to perform the required measurements, as well as a solid tridimensional model for volume measurement. This research will open the way to develop a capture methodology with an airborne camera using close range UAVs. An airborne platform will make possible to capture every individual in a forest plantation, furthermore if the analysis techniques applied in this research are automated it will be possible to calculate with high precision the exploit potential of a forest plantation and improve its management.

A practical application of photogrammetry to performing rib characterization measurements in an underground coal mine using a DSLR camera

PubMed Central

Slaker, Brent A.; Mohamed, Khaled M.

2017-01-01

Understanding coal mine rib behavior is important for inferring pillar loading conditions as well as ensuring the safety of miners who are regularly exposed to ribs. Due to the variability in the geometry of underground openings and ground behavior, point measurements often fail to capture the true movement of mine workings. Photogrammetry is a potentially fast, cheap, and precise supplemental measurement tool in comparison to extensometers, tape measures, or laser range meters, but its application in underground coal has been limited. The practical use of photogrammetry was tested at the Safety Research Coal Mine, National Institute for Occupational Safety and Health (NIOSH). A commercially available, digital single-lens reflex (DSLR) camera was used to perform the photogrammetric surveys for the experiment. Several experiments were performed using different lighting conditions, distances to subject, camera settings, and photograph overlaps, with results summarized as follows: the lighting method was found to be insignificant if the scene was appropriately illuminated. It was found that the distance to the subject has a minimal impact on result accuracy, and that camera settings have a significant impact on the photogrammetric quality of images. An increasing photograph resolution was preferable when measuring plane orientations; otherwise a high point cloud density would likely be excessive. Focal ratio (F-stop) changes affect the depth of field and image quality in situations where multiple angles are necessary to survey cleat orientations. Photograph overlap is very important to proper three-dimensional reconstruction, and at least 60% overlap between photograph pairs is ideal to avoid unnecessary post-processing. The suggestions and guidelines proposed are designed to increase the quality of photogrammetry inputs and outputs as well as minimize processing time, and serve as a starting point for an underground coal photogrammetry study. PMID:28663826

A practical application of photogrammetry to performing rib characterization measurements in an underground coal mine using a DSLR camera.

PubMed

Slaker, Brent A; Mohamed, Khaled M

2017-01-01

Understanding coal mine rib behavior is important for inferring pillar loading conditions as well as ensuring the safety of miners who are regularly exposed to ribs. Due to the variability in the geometry of underground openings and ground behavior, point measurements often fail to capture the true movement of mine workings. Photogrammetry is a potentially fast, cheap, and precise supplemental measurement tool in comparison to extensometers, tape measures, or laser range meters, but its application in underground coal has been limited. The practical use of photogrammetry was tested at the Safety Research Coal Mine, National Institute for Occupational Safety and Health (NIOSH). A commercially available, digital single-lens reflex (DSLR) camera was used to perform the photogrammetric surveys for the experiment. Several experiments were performed using different lighting conditions, distances to subject, camera settings, and photograph overlaps, with results summarized as follows: the lighting method was found to be insignificant if the scene was appropriately illuminated. It was found that the distance to the subject has a minimal impact on result accuracy, and that camera settings have a significant impact on the photogrammetric quality of images. An increasing photograph resolution was preferable when measuring plane orientations; otherwise a high point cloud density would likely be excessive. Focal ratio (F-stop) changes affect the depth of field and image quality in situations where multiple angles are necessary to survey cleat orientations. Photograph overlap is very important to proper three-dimensional reconstruction, and at least 60% overlap between photograph pairs is ideal to avoid unnecessary post-processing. The suggestions and guidelines proposed are designed to increase the quality of photogrammetry inputs and outputs as well as minimize processing time, and serve as a starting point for an underground coal photogrammetry study.

Scattering from Rock and Rock Outcrops

DTIC Science & Technology

2013-09-30

whose orientations and size distributions reflect the internal fault organization of the bedrock. A mathematical model of the leeward side of an...scattering from facets oriented close to normal incidence to the sonar system. Diffraction from sharp edges may also contribute strong scattering that 5 is...collected in a recent field experiment and are currently being analyzed. Figure 5 shows PhD student Derek Olson alongside the photogrammetry system

On the Quality of Point-Clouds Derived from Sfm-Photogrammetry Applied to UAS Imagery

NASA Astrophysics Data System (ADS)

Carbonneau, P.; James, T.

2014-12-01

Structure from Motion photogrammetry (SfM-photogrammetry) recently appeared in environmental sciences as an impressive tool allowing for the creation of topographic data from unstructured imagery. Several authors have tested the performance of SfM-photogrammetry vs that of TLS or dGPS. Whilst the initial results were very promising, there is currently a growing awareness that systematic deformations occur in DEMs and point-clouds derived from SfM-photogrammetry. Notably, some authors have identified a systematic doming manifest as an increasing error vs distance to the model centre. Simulation studies have confirmed that this error is due to errors in the calibration of camera distortions. This work aims to further investigate these effects in the presence of real data. We start with a dataset of 220 images acquired from a sUAS. After obtaining an initial self-calibration of the camera lens with Agisoft Photoscan, our method consists in applying systematic perturbations to 2 key lens parameters: Focal length and the k1 distortion parameter. For each perturbation, a point-cloud was produced and compared to LiDAR data. After deriving the mean and standard deviation of the error residuals (ɛ), a 2nd order polynomial surface was fitted to the errors point-cloud and the peak ɛ defined as the mathematical extrema of this surface. The results are presented in figure 1. This figure shows that lens perturbations can induce a range of errors with systematic behaviours. Peak ɛ is primarily controlled by K1 with a secondary control exerted by the focal length. These results allow us to state that: To limit the peak ɛ to 10cm, the K1 parameter must be calibrated to within 0.00025 and the focal length to within 2.5 pixels (≈10 µm). This level of calibration accuracy can only be achieved with proper design of image acquisition and control network geometry. Our main point is therefore that SfM is not a bypass to a rigorous and well-informed photogrammetric approach. Users of SfM-photogrammetry will still require basic training and knowledge in the fundamentals of photogrammetry. This is especially true for applications where very small topographic changes need to be detected or where gradient-sensitive processes need to be modelled.

Self-Calibrated In-Process Photogrammetry for Large Raw Part Measurement and Alignment before Machining

PubMed Central

Mendikute, Alberto; Zatarain, Mikel; Bertelsen, Álvaro; Leizea, Ibai

2017-01-01

Photogrammetry methods are being used more and more as a 3D technique for large scale metrology applications in industry. Optical targets are placed on an object and images are taken around it, where measuring traceability is provided by precise off-process pre-calibrated digital cameras and scale bars. According to the 2D target image coordinates, target 3D coordinates and camera views are jointly computed. One of the applications of photogrammetry is the measurement of raw part surfaces prior to its machining. For this application, post-process bundle adjustment has usually been adopted for computing the 3D scene. With that approach, a high computation time is observed, leading in practice to time consuming and user dependent iterative review and re-processing procedures until an adequate set of images is taken, limiting its potential for fast, easy-to-use, and precise measurements. In this paper, a new efficient procedure is presented for solving the bundle adjustment problem in portable photogrammetry. In-process bundle computing capability is demonstrated on a consumer grade desktop PC, enabling quasi real time 2D image and 3D scene computing. Additionally, a method for the self-calibration of camera and lens distortion has been integrated into the in-process approach due to its potential for highest precision when using low cost non-specialized digital cameras. Measurement traceability is set only by scale bars available in the measuring scene, avoiding the uncertainty contribution of off-process camera calibration procedures or the use of special purpose calibration artifacts. The developed self-calibrated in-process photogrammetry has been evaluated both in a pilot case scenario and in industrial scenarios for raw part measurement, showing a total in-process computing time typically below 1 s per image up to a maximum of 2 s during the last stages of the computed industrial scenes, along with a relative precision of 1/10,000 (e.g., 0.1 mm error in 1 m) with an error RMS below 0.2 pixels at image plane, ranging at the same performance reported for portable photogrammetry with precise off-process pre-calibrated cameras. PMID:28891946

Self-Calibrated In-Process Photogrammetry for Large Raw Part Measurement and Alignment before Machining.

PubMed

Mendikute, Alberto; Yagüe-Fabra, José A; Zatarain, Mikel; Bertelsen, Álvaro; Leizea, Ibai

2017-09-09

Photogrammetry methods are being used more and more as a 3D technique for large scale metrology applications in industry. Optical targets are placed on an object and images are taken around it, where measuring traceability is provided by precise off-process pre-calibrated digital cameras and scale bars. According to the 2D target image coordinates, target 3D coordinates and camera views are jointly computed. One of the applications of photogrammetry is the measurement of raw part surfaces prior to its machining. For this application, post-process bundle adjustment has usually been adopted for computing the 3D scene. With that approach, a high computation time is observed, leading in practice to time consuming and user dependent iterative review and re-processing procedures until an adequate set of images is taken, limiting its potential for fast, easy-to-use, and precise measurements. In this paper, a new efficient procedure is presented for solving the bundle adjustment problem in portable photogrammetry. In-process bundle computing capability is demonstrated on a consumer grade desktop PC, enabling quasi real time 2D image and 3D scene computing. Additionally, a method for the self-calibration of camera and lens distortion has been integrated into the in-process approach due to its potential for highest precision when using low cost non-specialized digital cameras. Measurement traceability is set only by scale bars available in the measuring scene, avoiding the uncertainty contribution of off-process camera calibration procedures or the use of special purpose calibration artifacts. The developed self-calibrated in-process photogrammetry has been evaluated both in a pilot case scenario and in industrial scenarios for raw part measurement, showing a total in-process computing time typically below 1 s per image up to a maximum of 2 s during the last stages of the computed industrial scenes, along with a relative precision of 1/10,000 (e.g. 0.1 mm error in 1 m) with an error RMS below 0.2 pixels at image plane, ranging at the same performance reported for portable photogrammetry with precise off-process pre-calibrated cameras.

Catchment-Scale Terrain Modelling with Structure-from-Motion Photogrammetry: a replacement for airborne lidar?

NASA Astrophysics Data System (ADS)

Brasington, J.

2015-12-01

Over the last five years, Structure-from-Motion photogrammetry has dramatically democratized the availability of high quality topographic data. This approach involves the use of a non-linear bundle adjustment to estimate simultaneously camera position, pose, distortion and 3D model coordinates. In contrast to traditional aerial photogrammetry, the bundle adjustment is typically solved without external constraints and instead ground control is used a posteriori to transform the modelled coordinates to an established datum using a similarity transformation. The limited data requirements, coupled with the ability to self-calibrate compact cameras, has led to a burgeoning of applications using low-cost imagery acquired terrestrially or from low-altitude platforms. To date, most applications have focused on relatively small spatial scales where relaxed logistics permit the use of dense ground control and high resolution, close-range photography. It is less clear whether this low-cost approach can be successfully upscaled to tackle larger, watershed-scale projects extending over 102-3 km2 where it could offer a competitive alternative to landscape modelling with airborne lidar. At such scales, compromises over the density of ground control, the speed and height of sensor platform and related image properties are inevitable. In this presentation we provide a systematic assessment of large-scale SfM terrain products derived for over 80 km2 of the braided Dart River and its catchment in the Southern Alps of NZ. Reference data in the form of airborne and terrestrial lidar are used to quantify the quality of 3D reconstructions derived from helicopter photography and used to establish baseline uncertainty models for geomorphic change detection. Results indicate that camera network design is a key determinant of model quality, and that standard aerial networks based on strips of nadir photography can lead to unstable camera calibration and systematic errors that are difficult to model with sparse ground control. We demonstrate how a low cost multi-camera platform providing both nadir and oblique imagery can support robust camera calibration, enabling the generation of high quality, large-scale terrain products that are suitable for precision fluvial change detection.

Catchment-Scale Terrain Modelling with Structure-from-Motion Photogrammetry: a replacement for airborne lidar?

NASA Astrophysics Data System (ADS)

Brasington, James; James, Joe; Cook, Simon; Cox, Simon; Lotsari, Eliisa; McColl, Sam; Lehane, Niall; Williams, Richard; Vericat, Damia

2016-04-01

In recent years, 3D terrain reconstructions based on Structure-from-Motion photogrammetry have dramatically democratized the availability of high quality topographic data. This approach involves the use of a non-linear bundle adjustment to estimate simultaneously camera position, pose, distortion and 3D model coordinates. In contrast to traditional aerial photogrammetry, the bundle adjustment is typically solved without external constraints and instead ground control is used a posteriori to transform the modelled coordinates to an established datum using a similarity transformation. The limited data requirements, coupled with the ability to self-calibrate compact cameras, has led to a burgeoning of applications using low-cost imagery acquired terrestrially or from low-altitude platforms. To date, most applications have focused on relatively small spatial scales (0.1-5 Ha), where relaxed logistics permit the use of dense ground control networks and high resolution, close-range photography. It is less clear whether this low-cost approach can be successfully upscaled to tackle larger, watershed-scale projects extending over 102-3 km2 where it could offer a competitive alternative to established landscape modelling with airborne lidar. At such scales, compromises over the density of ground control, the speed and height of sensor platform and related image properties are inevitable. In this presentation we provide a systematic assessment of the quality of large-scale SfM terrain products derived for over 80 km2 of the braided Dart River and its catchment in the Southern Alps of NZ. Reference data in the form of airborne and terrestrial lidar are used to quantify the quality of 3D reconstructions derived from helicopter photography and used to establish baseline uncertainty models for geomorphic change detection. Results indicate that camera network design is a key determinant of model quality, and that standard aerial photogrammetric networks based on strips of nadir photography can lead to unstable camera calibration and systematic errors that are difficult to model with sparse ground control. We demonstrate how a low cost multi-camera platform providing both nadir and oblique imagery can support robust camera calibration, enabling the generation of high quality, large-scale terrain products that are suitable for precision fluvial change detection.

Application of terrestrial photogrammetry for the mass balance calculation on Montasio Occidentale Glacier (Julian Alps, Italy)

NASA Astrophysics Data System (ADS)

Piermattei, Livia; Carturan, Luca; Calligaro, Simone; Blasone, Giacomo; Guarnieri, Alberto; Tarolli, Paolo; Dalla Fontana, Giancarlo; Vettore, Antonio

2014-05-01

Digital elevation models (DEMs) of glaciated terrain are commonly used to measure changes in geometry and hence infer the mass balance of glaciers. Different tools and methods exist to obtain information about the 3D geometry of terrain. Recent improvements on the quality and performance of digital cameras for close-range photogrammetry, and the development of automatic digital photogrammetric processing makes the 'structure from motion' photogrammetric technique (SfM) competitive for high quality 3D models production, compared to efficient but also expensive and logistically-demanding survey technologies such as airborn and terrestrial laser scanner (TLS). The purpose of this work is to test the SfM approach, using a consumer-grade SLR camera and the low-cost computer vision-based software package Agisoft Photoscan (Agisoft LLC), to monitor the mass balance of Montasio Occidentale glacier, a 0.07km2, low-altitude, debris-covered glacier located in the Eastern Italian Alps. The quality of the 3D models produced by the SfM process has been assessed by comparison with digital terrain models obtained through TLS surveys carried out at the same dates. TLS technique has indeed proved to be very effective in determining the volume change of this glacier in the last years. Our results shows that the photogrammetric approach can produce point cloud densities comparable to those derived from TLS measurements. Furthermore, the horizontal and vertical accuracies are also of the same order of magnitude as for TLS (centimetric to decimetric). The effect of different landscape characteristics (e.g. distance from the camera or terrain gradient) and of different substrata (rock, debris, ice, snow and firn) was also evaluated in terms of SfM reconstruction's accuracy vs. TLS. Given the good results obtained on the Montasio Occidentale glacier, it can be concluded that the terrestrial photogrammetry, with the advantageous features of portability, ease of use and above all low costs, allows to obtain high-resolution DEMs which enable good mass balance estimations on glaciers with similar characteristics.

Three-dimensional photogrammetric measurement of magnetic field lines in the WEGA stellarator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drewelow, Peter; Braeuer, Torsten; Otte, Matthias

2009-12-15

The magnetic confinement of plasmas in fusion experiments can significantly degrade due to perturbations of the magnetic field. A precise analysis of the magnetic field in a stellarator-type experiment utilizes electrons as test particles following the magnetic field line. The usual fluorescent detector for this electron beam limits the provided information to two-dimensional cut views at certain toroidal positions. However, the technique described in this article allows measuring the three-dimensional structure of the magnetic field by means of close-range photogrammetry. After testing and optimizing the main diagnostic components, measurements of the magnetic field lines were accomplished with a spatial resolutionmore » of 5 mm. The results agree with numeric calculations, qualifying this technique as an additional tool to investigate magnetic field configurations in a stellarator. For a possible future application, ways are indicated on how to reduce experimental error sources.« less

[Assessment of precision and accuracy of digital surface photogrammetry with the DSP 400 system].

PubMed

Krimmel, M; Kluba, S; Dietz, K; Reinert, S

2005-03-01

The objective of the present study was to evaluate the precision and accuracy of facial anthropometric measurements obtained through digital 3-D surface photogrammetry with the DSP 400 system in comparison to traditional 2-D photogrammetry. Fifty plaster casts of cleft infants were imaged and 21 standard anthropometric measurements were obtained. For precision assessment the measurements were performed twice in a subsample. Accuracy was determined by comparison of direct measurements and indirect 2-D and 3-D image measurements. Precision of digital surface photogrammetry was almost as good as direct anthropometry and clearly better than 2-D photogrammetry. Measurements derived from 3-D images showed better congruence to direct measurements than from 2-D photos. Digital surface photogrammetry with the DSP 400 system is sufficiently precise and accurate for craniofacial anthropometric examinations.

Using Photogrammetry to Estimate Tank Waste Volumes from Video

DOE Office of Scientific and Technical Information (OSTI.GOV)

Field, Jim G.

Washington River Protection Solutions (WRPS) contracted with HiLine Engineering & Fabrication, Inc. to assess the accuracy of photogrammetry tools as compared to video Camera/CAD Modeling System (CCMS) estimates. This test report documents the results of using photogrammetry to estimate the volume of waste in tank 241-C-I04 from post-retrieval videos and results using photogrammetry to estimate the volume of waste piles in the CCMS test video.

Comparison of roadway roughness derived from LIDAR and SFM 3D point clouds.

DOT National Transportation Integrated Search

2015-10-01

This report describes a short-term study undertaken to investigate the potential for using dense three-dimensional (3D) point : clouds generated from light detection and ranging (LIDAR) and photogrammetry to assess roadway roughness. Spatially : cont...

VirtoScan - a mobile, low-cost photogrammetry setup for fast post-mortem 3D full-body documentations in x-ray computed tomography and autopsy suites.

PubMed

Kottner, Sören; Ebert, Lars C; Ampanozi, Garyfalia; Braun, Marcel; Thali, Michael J; Gascho, Dominic

2017-03-01

Injuries such as bite marks or boot prints can leave distinct patterns on the body's surface and can be used for 3D reconstructions. Although various systems for 3D surface imaging have been introduced in the forensic field, most techniques are both cost-intensive and time-consuming. In this article, we present the VirtoScan, a mobile, multi-camera rig based on close-range photogrammetry. The system can be integrated into automated PMCT scanning procedures or used manually together with lifting carts, autopsy tables and examination couch. The VirtoScan is based on a moveable frame that carries 7 digital single-lens reflex cameras. A remote control is attached to each camera and allows the simultaneous triggering of the shutter release of all cameras. Data acquisition in combination with the PMCT scanning procedures took 3:34 min for the 3D surface documentation of one side of the body compared to 20:20 min of acquisition time when using our in-house standard. A surface model comparison between the high resolution output from our in-house standard and a high resolution model from the multi-camera rig showed a mean surface deviation of 0.36 mm for the whole body scan and 0.13 mm for a second comparison of a detailed section of the scan. The use of the multi-camera rig reduces the acquisition time for whole-body surface documentations in medico-legal examinations and provides a low-cost 3D surface scanning alternative for forensic investigations.

Computer Vision Photogrammetry for Underwater Archaeological Site Recording in a Low-Visibility Environment

NASA Astrophysics Data System (ADS)

Van Damme, T.

2015-04-01

Computer Vision Photogrammetry allows archaeologists to accurately record underwater sites in three dimensions using simple twodimensional picture or video sequences, automatically processed in dedicated software. In this article, I share my experience in working with one such software package, namely PhotoScan, to record a Dutch shipwreck site. In order to demonstrate the method's reliability and flexibility, the site in question is reconstructed from simple GoPro footage, captured in low-visibility conditions. Based on the results of this case study, Computer Vision Photogrammetry compares very favourably to manual recording methods both in recording efficiency, and in the quality of the final results. In a final section, the significance of Computer Vision Photogrammetry is then assessed from a historical perspective, by placing the current research in the wider context of about half a century of successful use of Analytical and later Digital photogrammetry in the field of underwater archaeology. I conclude that while photogrammetry has been used in our discipline for several decades now, for various reasons the method was only ever used by a relatively small percentage of projects. This is likely to change in the near future since, compared to the `traditional' photogrammetry approaches employed in the past, today Computer Vision Photogrammetry is easier to use, more reliable and more affordable than ever before, while at the same time producing more accurate and more detailed three-dimensional results.

A Method for Assessing the Accuracy of a Photogrammetry System for Precision Deployable Structures

NASA Technical Reports Server (NTRS)

Moore, Ashley

2005-01-01

The measurement techniques used to validate analytical models of large deployable structures are an integral Part of the technology development process and must be precise and accurate. Photogrammetry and videogrammetry are viable, accurate, and unobtrusive methods for measuring such large Structures. Photogrammetry uses Software to determine the three-dimensional position of a target using camera images. Videogrammetry is based on the same principle, except a series of timed images are analyzed. This work addresses the accuracy of a digital photogrammetry system used for measurement of large, deployable space structures at JPL. First, photogrammetry tests are performed on a precision space truss test article, and the images are processed using Photomodeler software. The accuracy of the Photomodeler results is determined through, comparison with measurements of the test article taken by an external testing group using the VSTARS photogrammetry system. These two measurements are then compared with Australis photogrammetry software that simulates a measurement test to predict its accuracy. The software is then used to study how particular factors, such as camera resolution and placement, affect the system accuracy to help design the setup for the videogrammetry system that will offer the highest level of accuracy for measurement of deploying structures.

Geodetic glacier mass balances at the push of a button: application of Structure from Motion technology on aerial images in mountain regions

NASA Astrophysics Data System (ADS)

Bolch, T.; Mölg, N.

2017-12-01

The application of Structure-from-Motion (SfM) to generate digital terrain models (DTMs) derived out of images from various kinds of sources has strongly increased in recent years. The major reason for this is its easy-to-use handling in comparison to conventional photogrammetry. In glaciology, DTMs are intensely used, among others, to calculate the geodetic mass balances. Few studies investigated the application of SfM to aerial images in mountainous terrain and results look promising. We tested this technique in a demanding environment in the Swiss Alps including very steep slopes, snow and ice covered terrain. SfM (using the commercial software packages of Agisoft Photoscan and Pix4DMapper) and conventional photogrammetry (ERDAS Photogrammetry) were applied on archival aerial images for nine dates between 1946 and 2005 the results were compared regarding bundle adjustment and final DTM quality. The overall precision of the DTMs could be defined with the use of a modern, high-quality reference DTM by Swisstopo. Results suggest a high performance of SfM to produce DTMs of similar quality as conventional photogrammetry. A ground resolution of high quality (little noise and artefacts) can be up to 50% higher, with 3-6 times less user effort. However, the controls on the commercial SfM software packages are limited in comparison to ERDAS Photogrammetry. SfM performs less reliably when few images with little overlap are processed. Overall, the uncertainty of DTMs from the different software are comparable and mostly within the uncertainty range of the reference DTM, making them highly valuable for glaciological purposes. Even though SfM facilitates the largely automated production of high quality DTMs, the user is not exempt from a thorough quality check, at best with reference data where available.

Integrating Unmanned Aerial Vehicles and Terrestrial Structure from Motion Photogrammetry for Assessing High Mountain Glacier Change, Huaytapallana, Peru

NASA Astrophysics Data System (ADS)

Wigmore, O.; Mark, B. G.; Lagos, P.; Somers, L. D.; McKenzie, J. M.; Huh, K. I.; Hopkinson, C.; Baraer, M.; Crumley, R. L.

2016-12-01

Terrestrial photogrammetry has a long and successful history of application to glaciological research. However, traditional methods rely upon large and expensive metric cameras and detailed triangulation of in-scene points for derivation of terrain models and analysis of glacier change. Recent developments in computer vision, including the advent of Structure from Motion (SfM) algorithms and associated software packages have made it possible to use consumer grade digital cameras to produce highly precise digital elevation models. This has facilitated the rapid expansion of unmanned aerial vehicles (UAVs) for mapping purposes. However, without onboard RTK GNSS positions of the UAV, within scene survey-grade ground targets are required for accurate georectification. Gaining access to mountain glaciers for the installation and survey of ground targets is often labour intensive, hazardous and sometimes impossible. Compounding this are limitations of UAV flight within these confined and high elevation locations and reduced flight times that limit the total survey area. Luckily, these environments also present a highly suitable location for the application of terrestrial SfM photogrammetry; because; high moraines, cliffs and ridgelines provide excellent 'semi-nadir' viewing of the glacier surface; while steep mountain walls present a close to nadir view from an oblique angle. In this study we present a workflow and results from an integrated UAV and terrestrial SfM photogrammetry campaign at Huaytapallana glacier, Huancayo Peru. We combined terrestrial images taken from GNSS surveyed positions with oblique UAV imagery of the mountain face. From this data a centimetre resolution orthomosaic and a decimetre resolution DEM of the snow and ice covered mountain face and proglacial lake were generated, covering over 6km2. Accuracy of the surface was determined from comparison over ice free areas to 1m aerial LiDAR data collected in 2009. Changes in glacier volume were then determined through DEM differencing with the LiDAR data.

Photogrammetry procedures applied to anthropometry.

PubMed

Okimoto, Maria Lúcialeite Ribeiro; Klein, Alison Alfred

2012-01-01

This study aims to evaluate the reliability and establish procedures for the use of digital photogrammetry in anthropometric measurements of the human hand. The methodology included the construction of a platform to allow the placement of the hand always equivalent to a distance of the camera lens and to annul the effects of parallax. We developed a software to perform the measurements from the images and built up a subject of proof in a cast from a negative mold, this object was subjected to measurements with digital photogrammetry using the data collection platform in caliper and the Coordinate Measuring Machine (MMC). The results of the application of photogrammetry in the data collection segment hand, allow us to conclude that photogrammetry is an effective presenting precision coefficient below 0.940. Within normal and acceptable values, given the magnitude of the data used in anthropometry. It was concluded photogrammetry then be reliable, accurate and efficient for carrying out anthropometric surveys of population, and presents less difficulty to collect in-place.

Close Range Photogrammetry in Space - Measuring the On-Orbit Clearance between Hardware on the International Space Station

NASA Technical Reports Server (NTRS)

Liddle, Donn

2017-01-01

When photogrammetrists read an article entitled "Photogrammetry in Space" they immediately think of terrestrial mapping using satellite imagery. However in the last 19 years the roll of close range photogrammetry in support of the manned space flight program has grown exponentially. Management and engineers have repeatedly entrusted the safety of the vehicles and their crews to the results of photogrammetric analysis. In February 2010, the Node 3 module was attached to the port side Common Berthing Mechanism (CBM) of the International Space Station (ISS). Since this was not the location at which the module was originally designed to be located on the ISS, coolant lines containing liquid ammonia, were installed externally from the US Lab to Node 3 during a spacewalk. During mission preparation I had developed a plan and a set of procedures to have the astronauts acquire stereo imagery of these coolant lines at the conclusion of the spacewalk to enable us to map their as-installed location relative to the rest of the space station. Unfortunately, the actual installation of the coolant lines took longer than expected and in an effort to wrap up the spacewalk on time, the mission director made a real-time call to drop the photography. My efforts to reschedule the photography on a later spacewalk never materialized, so rather than having an as-installed model for the location of coolant lines, the master ISS CAD database continued to display an as-designed model of the coolant lines. Fast forward to the summer of 2015, the ISS program planned to berth a Japanese cargo module to the nadir Common Berthing Mechanism (CBM), immediately adjacent to the Node 3 module. A CAD based clearance analysis revealed a negative four inch clearance between the ammonia lines and a thruster nozzle on the port side of the cargo vehicle. Recognizing that the model of the ammonia line used in the clearance analysis was "as-designed" rather than "as-installed", I was asked to determine the real clearance between the ammonia lines and expected position of the thruster bell using existing on-orbit imagery. Imagery of the area of interest, taken several years earlier from the Space Shuttle during a fly-around of the ISS, was found and used to set a stereo pair. Space Vision System Targets and Handrail bolts measured in the ISS analytical coordinate system (ISSACS) prior to launch, were used to obtain an absolute orientation so all photogrammetric measurement's would be in the ISSACS coordinate system. Coordinates for the design location of the edges of the thruster bell, when the cargo vehicle was fully berthed to the ISS, were displayed in 3-D relative to the as-installed ammonia lines. This immediately revealed a positive clearance, which was later quantified to be a minimum of 10" +/0.5". The analysis was completed over a single weekend by a single analyst. Using updated imagery, acquired from the station's robotic arm, a complete as-installed model of the coolant lines was generated from stereo photography and replaced the design model in the master ISS CAD database.

Laser photogrammetry improves size and demographic estimates for whale sharks

PubMed Central

Richardson, Anthony J.; Prebble, Clare E.M.; Marshall, Andrea D.; Bennett, Michael B.; Weeks, Scarla J.; Cliff, Geremy; Wintner, Sabine P.; Pierce, Simon J.

2015-01-01

Whale sharks Rhincodon typus are globally threatened, but a lack of biological and demographic information hampers an accurate assessment of their vulnerability to further decline or capacity to recover. We used laser photogrammetry at two aggregation sites to obtain more accurate size estimates of free-swimming whale sharks compared to visual estimates, allowing improved estimates of biological parameters. Individual whale sharks ranged from 432–917 cm total length (TL) (mean ± SD = 673 ± 118.8 cm, N = 122) in southern Mozambique and from 420–990 cm TL (mean ± SD = 641 ± 133 cm, N = 46) in Tanzania. By combining measurements of stranded individuals with photogrammetry measurements of free-swimming sharks, we calculated length at 50% maturity for males in Mozambique at 916 cm TL. Repeat measurements of individual whale sharks measured over periods from 347–1,068 days yielded implausible growth rates, suggesting that the growth increment over this period was not large enough to be detected using laser photogrammetry, and that the method is best applied to estimating growth rates over longer (decadal) time periods. The sex ratio of both populations was biased towards males (74% in Mozambique, 89% in Tanzania), the majority of which were immature (98% in Mozambique, 94% in Tanzania). The population structure for these two aggregations was similar to most other documented whale shark aggregations around the world. Information on small (<400 cm) whale sharks, mature individuals, and females in this region is lacking, but necessary to inform conservation initiatives for this globally threatened species. PMID:25870776

Performance Evaluation of 3d Modeling Software for Uav Photogrammetry

NASA Astrophysics Data System (ADS)

Yanagi, H.; Chikatsu, H.

2016-06-01

UAV (Unmanned Aerial Vehicle) photogrammetry, which combines UAV and freely available internet-based 3D modeling software, is widely used as a low-cost and user-friendly photogrammetry technique in the fields such as remote sensing and geosciences. In UAV photogrammetry, only the platform used in conventional aerial photogrammetry is changed. Consequently, 3D modeling software contributes significantly to its expansion. However, the algorithms of the 3D modelling software are black box algorithms. As a result, only a few studies have been able to evaluate their accuracy using 3D coordinate check points. With this motive, Smart3DCapture and Pix4Dmapper were downloaded from the Internet and commercial software PhotoScan was also employed; investigations were performed in this paper using check points and images obtained from UAV.

Quality Inspection and Analysis of Three-Dimensional Geographic Information Model Based on Oblique Photogrammetry

NASA Astrophysics Data System (ADS)

Dong, S.; Yan, Q.; Xu, Y.; Bai, J.

2018-04-01

In order to promote the construction of digital geo-spatial framework in China and accelerate the construction of informatization mapping system, three-dimensional geographic information model emerged. The three-dimensional geographic information model based on oblique photogrammetry technology has higher accuracy, shorter period and lower cost than traditional methods, and can more directly reflect the elevation, position and appearance of the features. At this stage, the technology of producing three-dimensional geographic information models based on oblique photogrammetry technology is rapidly developing. The market demand and model results have been emerged in a large amount, and the related quality inspection needs are also getting larger and larger. Through the study of relevant literature, it is found that there are a lot of researches on the basic principles and technical characteristics of this technology, and relatively few studies on quality inspection and analysis. On the basis of summarizing the basic principle and technical characteristics of oblique photogrammetry technology, this paper introduces the inspection contents and inspection methods of three-dimensional geographic information model based on oblique photogrammetry technology. Combined with the actual inspection work, this paper summarizes the quality problems of three-dimensional geographic information model based on oblique photogrammetry technology, analyzes the causes of the problems and puts forward the quality control measures. It provides technical guidance for the quality inspection of three-dimensional geographic information model data products based on oblique photogrammetry technology in China and provides technical support for the vigorous development of three-dimensional geographic information model based on oblique photogrammetry technology.

Application of photogrammetry to work in nuclear power plants in operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abella, A.P.; Balsalobre, F.S.

1987-01-01

In the evolution of requirements applicable to nuclear safety-related components and the obtainment of as-built data for a great variety of jobs performed in nuclear power plants, photogrammetry proves to be a very useful tool for design, manufacture, erection, maintenance, and operation. The METADAT data acquisition system developed by Empresarios Agrupados has a wide range of applications, depending on the degree of precision required. The F-3 system is capable of obtaining a precision of 1:10.000, to 0.10 mm in determined zones, through the use of wide-angle lenses without optical distortions or aberrations. In cases where such a high degree ofmore » precision is not necessary, as in piping run modifications, conduits, or cable trays, the F-2 system can be used.« less

Laser-Induced-Fluorescence Photogrammetry and Videogrammetry

NASA Technical Reports Server (NTRS)

Danehy, Paul; Jones, Tom; Connell, John; Belvin, Keith; Watson, Kent

2004-01-01

An improved method of dot-projection photogrammetry and an extension of the method to encompass dot-projection videogrammetry overcome some deficiencies of dot-projection photogrammetry as previously practiced. The improved method makes it possible to perform dot-projection photogrammetry or videogrammetry on targets that have previously not been amenable to dot-projection photogrammetry because they do not scatter enough light. Such targets include ones that are transparent, specularly reflective, or dark. In standard dot-projection photogrammetry, multiple beams of white light are projected onto the surface of an object of interest (denoted the target) to form a known pattern of bright dots. The illuminated surface is imaged in one or more cameras oriented at a nonzero angle or angles with respect to a central axis of the illuminating beams. The locations of the dots in the image(s) contain stereoscopic information on the locations of the dots, and, hence, on the location, shape, and orientation of the illuminated surface of the target. The images are digitized and processed to extract this information. Hardware and software to implement standard dot-projection photogrammetry are commercially available. Success in dot-projection photogrammetry depends on achieving sufficient signal-to-noise ratios: that is, it depends on scattering of enough light by the target so that the dots as imaged in the camera(s) stand out clearly against the ambient-illumination component of the image of the target. In one technique used previously to increase the signal-to-noise ratio, the target is illuminated by intense, pulsed laser light and the light entering the camera(s) is band-pass filtered at the laser wavelength. Unfortunately, speckle caused by the coherence of the laser light engenders apparent movement in the projected dots, thereby giving rise to errors in the measurement of the centroids of the dots and corresponding errors in the computed shape and location of the surface of the target. The improved method is denoted laser-induced-fluorescence photogrammetry.

Model deformation measurements at a cryogenic wind tunnel using photogrammetry

NASA Technical Reports Server (NTRS)

Burner, A. W.; Snow, W. L.; Goad, W. K.

1985-01-01

A photogrammetric closed circuit television system to measure model deformation at the National Transonic Facility (NTF) is described. The photogrammetric approach was chosen because of its inherent rapid data recording of the entire object field. Video cameras are used to acquire data instead of film cameras due to the inaccessibility of cameras which must be housed within the cryogenic, high pressure plenum of this facility. Data reduction procedures and the results of tunnel tests at the NTF are presented.

Model Deformation Measurements at a Cryogenic Wind Tunnel Using Photogrammetry

NASA Technical Reports Server (NTRS)

Burner, A. W.; Snow, W. L.; Goad, W. K.

1982-01-01

A photogrammetric closed circuit television system to measure model deformation at the National Transonic Facility (NTF) is described. The photogrammetric approach was chosen because of its inherent rapid data recording of the entire object field. Video cameras are used to acquire data instead of film cameras due to the inaccessibility of cameras which must be housed within the cryogenic, high pressure plenum of this facility. Data reduction procedures and the results of tunnel tests at the NTF are presented.

Lightweight UAV with on-board photogrammetry and single-frequency GPS positioning for metrology applications

NASA Astrophysics Data System (ADS)

Daakir, M.; Pierrot-Deseilligny, M.; Bosser, P.; Pichard, F.; Thom, C.; Rabot, Y.; Martin, O.

2017-05-01

This article presents a coupled system consisting of a single-frequency GPS receiver and a light photogrammetric quality camera embedded in an Unmanned Aerial Vehicle (UAV). The aim is to produce high quality data that can be used in metrology applications. The issue of Integrated Sensor Orientation (ISO) of camera poses using only GPS measurements is presented and discussed. The accuracy reached by our system based on sensors developed at the French Mapping Agency (IGN) Opto-Electronics, Instrumentation and Metrology Laboratory (LOEMI) is qualified. These sensors are specially designed for close-range aerial image acquisition with a UAV. Lever-arm calibration and time synchronization are explained and performed to reach maximum accuracy. All processing steps are detailed from data acquisition to quality control of final products. We show that an accuracy of a few centimeters can be reached with this system which uses low-cost UAV and GPS module coupled with the IGN-LOEMI home-made camera.

Cultural Heritage Documentation in SIS Environment: AN Application for "PORTA SIRENA" in the Archaeological Site of Paestum

NASA Astrophysics Data System (ADS)

Pepe, M.; Parente, C.

2017-05-01

The Heritage Documentation allows the monitoring, maintenance and conservation by the most recent, efficient investigation techniques and storage of data. A key role in Heritage Documentation is represented by the Geographic Information Systems (GIS) and Spatial Information System (SIS), thanks to the possibility offered by this instrument not only to connect spatial elements (geographical features) to attribute tables, but also manage various information in the form of raster (terrestrial, aerial and satellite imagery), 3D point clouds, 3D models and other vector data. The paper describes all the activities that lead to the construction of a SIS, especially in relation to the new survey technologies with particular focus at survey performed by Close Range Photogrammetry (CRP). In addition, after explaining the relationships between the different information systems that contribute towards creating of a SIS and the various professions involved, a case study in Paestum area (Italy), showing the efficiency of Spatial Information System (SIS) technology, is discussed.

Multitemporal Accuracy and Precision Assessment of Unmanned Aerial System Photogrammetry for Slope-Scale Snow Depth Maps in Alpine Terrain

NASA Astrophysics Data System (ADS)

Adams, Marc S.; Bühler, Yves; Fromm, Reinhard

2017-12-01

Reliable and timely information on the spatio-temporal distribution of snow in alpine terrain plays an important role for a wide range of applications. Unmanned aerial system (UAS) photogrammetry is increasingly applied to cost-efficiently map the snow depth at very high resolution with flexible applicability. However, crucial questions regarding quality and repeatability of this technique are still under discussion. Here we present a multitemporal accuracy and precision assessment of UAS photogrammetry for snow depth mapping on the slope-scale. We mapped a 0.12 km2 large snow-covered study site, located in a high-alpine valley in Western Austria. 12 UAS flights were performed to acquire imagery at 0.05 m ground sampling distance in visible (VIS) and near-infrared (NIR) wavelengths with a modified commercial, off-the-shelf sensor mounted on a custom-built fixed-wing UAS. The imagery was processed with structure-from-motion photogrammetry software to generate orthophotos, digital surface models (DSMs) and snow depth maps (SDMs). Accuracy of DSMs and SDMs were assessed with terrestrial laser scanning and manual snow depth probing, respectively. The results show that under good illumination conditions (study site in full sunlight), the DSMs and SDMs were acquired with an accuracy of ≤ 0.25 and ≤ 0.29 m (both at 1σ), respectively. In case of poorly illuminated snow surfaces (study site shadowed), the NIR imagery provided higher accuracy (0.19 m; 0.23 m) than VIS imagery (0.49 m; 0.37 m). The precision of the UASSDMs was 0.04 m for a small, stable area and below 0.33 m for the whole study site (both at 1σ).

Photogrammetry and Remote Sensing: New German Standards (din) Setting Quality Requirements of Products Generated by Digital Cameras, Pan-Sharpening and Classification

NASA Astrophysics Data System (ADS)

Reulke, R.; Baltrusch, S.; Brunn, A.; Komp, K.; Kresse, W.; von Schönermark, M.; Spreckels, V.

2012-08-01

10 years after the first introduction of a digital airborne mapping camera in the ISPRS conference 2000 in Amsterdam, several digital cameras are now available. They are well established in the market and have replaced the analogue camera. A general improvement in image quality accompanied the digital camera development. The signal-to-noise ratio and the dynamic range are significantly better than with the analogue cameras. In addition, digital cameras can be spectrally and radiometrically calibrated. The use of these cameras required a rethinking in many places though. New data products were introduced. In the recent years, some activities took place that should lead to a better understanding of the cameras and the data produced by these cameras. Several projects, like the projects of the German Society for Photogrammetry, Remote Sensing and Geoinformation (DGPF) or EuroSDR (European Spatial Data Research), were conducted to test and compare the performance of the different cameras. In this paper the current DIN (Deutsches Institut fuer Normung - German Institute for Standardization) standards will be presented. These include the standard for digital cameras, the standard for ortho rectification, the standard for classification, and the standard for pan-sharpening. In addition, standards for the derivation of elevation models, the use of Radar / SAR, and image quality are in preparation. The OGC has indicated its interest in participating that development. The OGC has already published specifications in the field of photogrammetry and remote sensing. One goal of joint future work could be to merge these formerly independent developments and the joint development of a suite of implementation specifications for photogrammetry and remote sensing.

Characterization of measurement errors using structure-from-motion and photogrammetry to measure marine habitat structural complexity.

PubMed

Bryson, Mitch; Ferrari, Renata; Figueira, Will; Pizarro, Oscar; Madin, Josh; Williams, Stefan; Byrne, Maria

2017-08-01

Habitat structural complexity is one of the most important factors in determining the makeup of biological communities. Recent advances in structure-from-motion and photogrammetry have resulted in a proliferation of 3D digital representations of habitats from which structural complexity can be measured. Little attention has been paid to quantifying the measurement errors associated with these techniques, including the variability of results under different surveying and environmental conditions. Such errors have the potential to confound studies that compare habitat complexity over space and time. This study evaluated the accuracy, precision, and bias in measurements of marine habitat structural complexity derived from structure-from-motion and photogrammetric measurements using repeated surveys of artificial reefs (with known structure) as well as natural coral reefs. We quantified measurement errors as a function of survey image coverage, actual surface rugosity, and the morphological community composition of the habitat-forming organisms (reef corals). Our results indicated that measurements could be biased by up to 7.5% of the total observed ranges of structural complexity based on the environmental conditions present during any particular survey. Positive relationships were found between measurement errors and actual complexity, and the strength of these relationships was increased when coral morphology and abundance were also used as predictors. The numerous advantages of structure-from-motion and photogrammetry techniques for quantifying and investigating marine habitats will mean that they are likely to replace traditional measurement techniques (e.g., chain-and-tape). To this end, our results have important implications for data collection and the interpretation of measurements when examining changes in habitat complexity using structure-from-motion and photogrammetry.

Digital photogrammetry for quantitative wear analysis of retrieved TKA components.

PubMed

Grochowsky, J C; Alaways, L W; Siskey, R; Most, E; Kurtz, S M

2006-11-01

The use of new materials in knee arthroplasty demands a way in which to accurately quantify wear in retrieved components. Methods such as damage scoring, coordinate measurement, and in vivo wear analysis have been used in the past. The limitations in these methods illustrate a need for a different methodology that can accurately quantify wear, which is relatively easy to perform and uses a minimal amount of expensive equipment. Off-the-shelf digital photogrammetry represents a potentially quick and easy alternative to what is readily available. Eighty tibial inserts were visually examined for front and backside wear and digitally photographed in the presence of two calibrated reference fields. All images were segmented (via manual and automated algorithms) using Adobe Photoshop and National Institute of Health ImageJ. Finally, wear was determined using ImageJ and Rhinoceros software. The absolute accuracy of the method and repeatability/reproducibility by different observers were measured in order to determine the uncertainty of wear measurements. To determine if variation in wear measurements was due to implant design, 35 implants of the three most prevalent designs were subjected to retrieval analysis. The overall accuracy of area measurements was 97.8%. The error in automated segmentation was found to be significantly lower than that of manual segmentation. The photogrammetry method was found to be reasonably accurate and repeatable in measuring 2-D areas and applicable to determining wear. There was no significant variation in uncertainty detected among different implant designs. Photogrammetry has a broad range of applicability since it is size- and design-independent. A minimal amount of off-the-shelf equipment is needed for the procedure and no proprietary knowledge of the implant is needed. (c) 2006 Wiley Periodicals, Inc.

Data filtering with support vector machines in geometric camera calibration.

PubMed

Ergun, B; Kavzoglu, T; Colkesen, I; Sahin, C

2010-02-01

The use of non-metric digital cameras in close-range photogrammetric applications and machine vision has become a popular research agenda. Being an essential component of photogrammetric evaluation, camera calibration is a crucial stage for non-metric cameras. Therefore, accurate camera calibration and orientation procedures have become prerequisites for the extraction of precise and reliable 3D metric information from images. The lack of accurate inner orientation parameters can lead to unreliable results in the photogrammetric process. A camera can be well defined with its principal distance, principal point offset and lens distortion parameters. Different camera models have been formulated and used in close-range photogrammetry, but generally sensor orientation and calibration is performed with a perspective geometrical model by means of the bundle adjustment. In this study, support vector machines (SVMs) using radial basis function kernel is employed to model the distortions measured for Olympus Aspherical Zoom lens Olympus E10 camera system that are later used in the geometric calibration process. It is intended to introduce an alternative approach for the on-the-job photogrammetric calibration stage. Experimental results for DSLR camera with three focal length settings (9, 18 and 36 mm) were estimated using bundle adjustment with additional parameters, and analyses were conducted based on object point discrepancies and standard errors. Results show the robustness of the SVMs approach on the correction of image coordinates by modelling total distortions on-the-job calibration process using limited number of images.

Forest structure analysis combining laser scanning with digital airborne photogrammetry

NASA Astrophysics Data System (ADS)

Lissak, Candide; Onda, Yuichi; Kato, Hiroaki

2017-04-01

The interest of Light Detection and Ranging (LiDAR) for vegetation structure analysis has been demonstrated in several research context. Indeed, airborne or ground Lidar surveys can provide detailed three-dimensional data of the forest structure from understorey forest to the canopy. To characterize at different timescale the vegetation components in dense cedar forests we can combine several sources point clouds from Lidar survey and photogrammetry data. For our study, Terrestrial Laser Scanning (TLS-Leica ScanStation C10 processed with Cyclone software) have been lead in three forest areas (≈ 200m2 each zone) mainly composed of japanese cedar (Japonica cryptomeria), in the region of Fukushima (Japan). The study areas are characterized by various vegetation densities. For the 3 areas, Terrestrial laser scanning has been performed from several location points and several heights. Various floors shootings (ground, 4m, 6m and 18m high) were able with the use of a several meters high tower implanted to study the canopy evolution following the Fukushima Daiishi nuclear power plant accident. The combination of all scanners provides a very dense 3D point cloud of ground and canopy structure (average 300 000 000 points). For the Tochigi forest area, a first test of a low-cost Unmanned Aerial Vehicle (UAV) photogrammetry has been lead and calibrated by ground GPS measurements to determine the coordinates of points. TLS combined to UAV photogrammetry make it possible to obtain information on vertical and horizontal structure of the Tochigi forest. This combination of technologies will allow the forest structure mapping, morphometry analysis and the assessment of biomass volume evolution from multi-temporal point clouds. In our research, we used a low-cost UAV 3 Advanced (200 m2 cover, 1300 pictures...). Data processing were performed using PotoScan Pro software to obtain a very dense point clouds to combine to TLS data set. This low-cost UAV photogrammetry data has been successfully used to derive information on the canopy cover. The purpose of this poster is to present the usability of combined remote sensing methods for forest structure analysis and 3D model reconstitution for a trend analysis of the forest changes.

Integrating terrestrial LiDAR and stereo photogrammetry to map the Tolay lakebed in northern San Francisco Bay

USGS Publications Warehouse

Woo, Isa; Storesund,; Takekawa, John Y.; Gardiner, Rachel J.; Ehret,

2009-01-01

The Tolay Creek Watershed drains approximately 3,520 ha along the northern edge of San Francisco Bay. Surrounded by a mosaic of open space conservation easements and public wildlife areas, it is one of the only watersheds in this urbanized estuary that is protected from its headwaters to the bay. Tolay Lake is a seasonal, spring-fed lake found in the upper watershed that historically extended over 120 ha. Although the lakebed was farmed since the early 1860s, the majority of the lakebed was recently acquired by the Sonoma County Regional Parks Department to restore its natural habitat values. As part of the restoration planning process, we produced a digital elevation model (DEM) of the historic extent of Tolay Lake by integrating terrestrial LiDAR (light detection and ranging) and stereo photogrammetry datasets, and real-time kinematic (RTK) global positioning system (GPS) surveys. We integrated the data, generated a DEM of the lakebed and upland areas, and analyzed errors. The accuracy of the composite DEM was verified using spot elevations obtained from the RTK GPS. Thus, we found that by combining photogrammetry, terrestrial LiDAR, and RTK GPS, we created an accurate baseline elevation map to use in watershed restoration planning and design.

A paired-laser photogrammetric method for in situ length measurement of benthic fishes

USGS Publications Warehouse

Rizzo, Austin A.; Welsh, Stuart A.; Thompson, Patricia A.

2017-01-01

Photogrammetry, a technique to obtain measurements from photographs, may be a valid method for measuring lengths of rare, threatened, or endangered species. Photogrammetric methods of measurement are nonintrusive and reduce the possibility of physical damage or physiological stress associated with the capture and handling of individuals. We evaluated precision and accuracy of photogrammetric length measurements relative to board measurements of Greenside Darters Etheostoma blennioides and Variegate Darters E. variatum in an aquarium and applied photogrammetry in a field study of the Diamond Darter Crystallaria cincotta, a federally listed endangered species. Digital photographs were taken of each individual using a waterproof camera equipped with two parallel lasers. Photogrammetric length measurements were digitized with ImageJ software. Agreement between board and photogrammetric measurements were high for Greenside and Variegate darters. The magnitude of differences was small between direct and photogrammetric measurements, ranging from 0.6% to 3.1%, depending on the species measured and the type of measurement taken. These results support photogrammetry as a useful method for obtaining length measurements of benthic stream fishes. Photogrammetric methods allowed for length measurements and an assessment of length frequency of 199 Diamond Darters, informative data for management that could not be collected with conventional measuring-board methods.

[Reliability of iWitness photogrammetry in maxillofacial application].

PubMed

Jiang, Chengcheng; Song, Qinggao; He, Wei; Chen, Shang; Hong, Tao

2015-06-01

This study aims to test the accuracy and precision of iWitness photogrammetry for measuring the facial tissues of mannequin head. Under ideal circumstances, the 3D landmark coordinates were repeatedly obtained from a mannequin head using iWitness photogrammetric system with different parameters, to examine the precision of this system. The differences between the 3D data and their true distance values of mannequin head were computed. Operator error of 3D system in non-zoom and zoom status were 0.20 mm and 0.09 mm, and the difference was significant (P 0.05). Image captured error of 3D system was 0.283 mm, and there was no significant difference compared with the same group of images (P>0.05). Error of 3D systen with recalibration was 0.251 mm, and the difference was not statistically significant compared with image captured error (P>0.05). Good congruence was observed between means derived from the 3D photos and direct anthropometry, with difference ranging from -0.4 mm to +0.4 mm. This study provides further evidence of the high reliability of iWitness photogrammetry for several craniofacial measurements, including landmarks and inter-landmark distances. The evaluated system can be recommended for the evaluation and documentation of the facial surface.

High Resolution Topography of Polar Regions from Commercial Satellite Imagery, Petascale Computing and Open Source Software

NASA Astrophysics Data System (ADS)

Morin, Paul; Porter, Claire; Cloutier, Michael; Howat, Ian; Noh, Myoung-Jong; Willis, Michael; Kramer, WIlliam; Bauer, Greg; Bates, Brian; Williamson, Cathleen

2017-04-01

Surface topography is among the most fundamental data sets for geosciences, essential for disciplines ranging from glaciology to geodynamics. Two new projects are using sub-meter, commercial imagery licensed by the National Geospatial-Intelligence Agency and open source photogrammetry software to produce a time-tagged 2m posting elevation model of the Arctic and an 8m posting reference elevation model for the Antarctic. When complete, this publically available data will be at higher resolution than any elevation models that cover the entirety of the Western United States. These two polar projects are made possible due to three equally important factors: 1) open-source photogrammetry software, 2) petascale computing, and 3) sub-meter imagery licensed to the United States Government. Our talk will detail the technical challenges of using automated photogrammetry software; the rapid workflow evolution to allow DEM production; the task of deploying the workflow on one of the world's largest supercomputers; the trials of moving massive amounts of data, and the management strategies the team needed to solve in order to meet deadlines. Finally, we will discuss the implications of this type of collaboration for future multi-team use of leadership-class systems such as Blue Waters, and for further elevation mapping.

Digital 2D-photogrammetry and direct anthropometry--a comparing study on test accomplishment and measurement data.

PubMed

Franke-Gromberg, Christine; Schüler, Grit; Hermanussen, Michael; Scheffler, Christiane

2010-01-01

The aim of this methodological anthropometric study was to compare direct anthropometry and digital two-dimensional photogrammetry in 18 male and 27 female subjects, aged 24 to 65 years, from Potsdam, Germany. In view of the rising interest in reliable biometric kephalofacial data, we focussed on head and face measurements. Out of 34 classic facial anatomical landmarks, 27 landmarks were investigated both by direct anthropometry and 2D-photogrammetry; 7 landmarks could not be localized by 2D-photogrammetry. Twenty-six kephalofacial distances were analysed both by direct anthropometry and digital 2D-photogrammetry. Kephalofacial distances are on average 7.6% shorter when obtained by direct anthropometry. The difference between the two techniques is particularly evident in total head height (vertex-gnathion) due to the fact that vertex is usually covered by hair and escapes from photogrammetry. Also the distances photographic sellion-gnathion (1.3 cm, i. e. 11.6%) and nasal-gnathion (1.2 cm, i. e. 9.4%) differ by more than one centimetre. Differences below 0.5 cm between the two techniques were found when measuring mucosa-lip-height (2.2%), gonia (3.0%), glabella-stomion (3.9%), and nose height (glabella-subnasal) (4.0%). Only the estimates of forehead width were significantly narrower when obtained by 2D-photogrammetry (-1.4 cm, -13.1%). The methodological differences increased with increasing magnitude of the kephalometric distance. Apart from these limitations, both techniques are similarly valid and may replace each other.

Validation of Laser-Induced Fluorescent Photogrammetric Targets on Membrane Structures

NASA Technical Reports Server (NTRS)

Jones, Thomas W.; Dorrington, Adrian A.; Shortis, Mark R.; Hendricks, Aron R.

2004-01-01

The need for static and dynamic characterization of a new generation of inflatable space structures requires the advancement of classical metrology techniques. A new photogrammetric-based method for non-contact ranging and surface profiling has been developed at NASA Langley Research Center (LaRC) to support modal analyses and structural validation of this class of space structures. This full field measurement method, known as Laser-Induced Fluorescence (LIF) photogrammetry, has previously yielded promising experimental results. However, data indicating the achievable measurement precision had not been published. This paper provides experimental results that indicate the LIF-photogrammetry measurement precision for three different target types used on a reflective membrane structure. The target types were: (1) non-contact targets generated using LIF, (2) surface attached retro-reflective targets, and (3) surface attached diffuse targets. Results from both static and dynamic investigations are included.

Three-Dimensional Digital Documentation of Heritage Sites Using Terrestrial Laser Scanning and Unmanned Aerial Vehicle Photogrammetry

NASA Astrophysics Data System (ADS)

Jo, Y. H.; Kim, J. Y.

2017-08-01

Three-dimensional digital documentation is an important technique for the maintenance and monitoring of cultural heritage sites. This study focuses on the three-dimensional digital documentation of the Magoksa Temple, Republic of Korea, using a combination of terrestrial laser scanning and unmanned aerial vehicle (UAV) photogrammetry. Terrestrial laser scanning mostly acquired the vertical geometry of the buildings. In addition, the digital orthoimage produced by UAV photogrammetry had higher horizontal data acquisition rate than that produced by terrestrial laser scanning. Thus, the scanning and UAV photogrammetry were merged by matching 20 corresponding points and an absolute coordinate system was established using seven ground control points. The final, complete threedimensional shape had perfect horizontal and vertical geometries. This study demonstrates the potential of integrating terrestrial laser scanning and UAV photogrammetry for three-dimensional digital documentation. This new technique is expected to contribute to the three-dimensional digital documentation and spatial analysis of cultural heritage sites.

Procedures of assessment on the quantification of thoracic kyphosis and lumbar lordosis by radiography and photogrammetry: A literature review.

PubMed

Porto, Alessandra Beggiato; Okazaki, Victor Hugo Alves

2017-10-01

The quantification of thoracic kyphosis and lumbar lordosis can be assessed in different ways; among them radiography and photogrammetry. However, the assessment procedures are not consistent in the literature for either method. The objective of this study was to conduct a literature review about postural assessment through radiography and photogrammetry, for delineating the procedures for both methods. In total 38 studies were selected by an online search in the MEDLINE and LILACS databases with the keywords: radiograph and posture, postural alignment, photogrammetry or photometry or biophotogrammetry. For the radiographic method, the results showed divergences in arm positioning and in the calculation of thoracic and lumbar angles. The photogrammetry demonstrated differences in relation to the camera, tripod, plumb line and feet positioning, angle calculation, software utilization, and the use of footwear. Standardization is proposed for both methods to help establish normative values and comparisons between diagnoses. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photogrammetry - Remote Sensing and Geoinformation

NASA Astrophysics Data System (ADS)

Lazaridou, M. A.; Patmio, E. N.

2012-07-01

Earth and its environment are studied by different scientific disciplines as geosciences, science of engineering, social sciences, geography, etc. The study of the above, beyond pure scientific interest, is useful for the practical needs of man. Photogrammetry and Remote Sensing (defined by Statute II of ISPRS) is the art, science, and technology of obtaining reliable information from non-contact imaging and other sensor systems about the Earth and its environment, and other physical objects and of processes through recording, measuring, analyzing and representation. Therefore, according to this definition, photogrammetry and remote sensing can support studies of the above disciplines for acquisition of geoinformation. This paper concerns basic concepts of geosciences (geomorphology, geology, hydrology etc), and the fundamentals of photogrammetry-remote sensing, in order to aid the understanding of the relationship between photogrammetry-remote sensing and geoinformation and also structure curriculum in a brief, concise and coherent way. This curriculum can represent an appropriate research and educational outline and help to disseminate knowledge in various directions and levels. It resulted from our research and educational experience in graduate and post-graduate level (post-graduate studies relative to the protection of environment and protection of monuments and historical centers) in the Lab. of Photogrammetry - Remote Sensing in Civil Engineering Faculty of Aristotle University of Thessaloniki.

American Society for Photogrammetry and Remote Sensing and ACSM, Fall Convention, Reno, NV, Oct. 4-9, 1987, ASPRS Technical Papers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-01-01

Recent advances in remote-sensing technology and applications are examined in reviews and reports. Topics addressed include the use of Landsat TM data to assess suspended-sediment dispersion in a coastal lagoon, the use of sun incidence angle and IR reflectance levels in mapping old-growth coniferous forests, information-management systems, Large-Format-Camera soil mapping, and the economic potential of Landsat TM winter-wheat crop-condition assessment. Consideration is given to measurement of ephemeral gully erosion by airborne laser ranging, the creation of a multipurpose cadaster, high-resolution remote sensing and the news media, the role of vegetation in the global carbon cycle, PC applications in analytical photogrammetry,more » multispectral geological remote sensing of a suspected impact crater, fractional calculus in digital terrain modeling, and automated mapping using GP-based survey data.« less

D Modeling with Photogrammetry by Uavs and Model Quality Verification

NASA Astrophysics Data System (ADS)

Barrile, V.; Bilotta, G.; Nunnari, A.

2017-11-01

This paper deals with a test lead by Geomatics laboratory (DICEAM, Mediterranea University of Reggio Calabria), concerning the application of UAV photogrammetry for survey, monitoring and checking. The study case relies with the surroundings of the Department of Agriculture Sciences. In the last years, such area was interested by landslides and survey activities carried out to take the phenomenon under control. For this purpose, a set of digital images were acquired through a UAV equipped with a digital camera and GPS. Successively, the processing for the production of a 3D georeferenced model was performed by using the commercial software Agisoft PhotoScan. Similarly, the use of a terrestrial laser scanning technique allowed to product dense cloud and 3D models of the same area. To assess the accuracy of the UAV-derived 3D models, a comparison between image and range-based methods was performed.

Image-based surface reconstruction in geomorphometry - merits, limits and developments

NASA Astrophysics Data System (ADS)

Eltner, Anette; Kaiser, Andreas; Castillo, Carlos; Rock, Gilles; Neugirg, Fabian; Abellán, Antonio

2016-05-01

Photogrammetry and geosciences have been closely linked since the late 19th century due to the acquisition of high-quality 3-D data sets of the environment, but it has so far been restricted to a limited range of remote sensing specialists because of the considerable cost of metric systems for the acquisition and treatment of airborne imagery. Today, a wide range of commercial and open-source software tools enable the generation of 3-D and 4-D models of complex geomorphological features by geoscientists and other non-experts users. In addition, very recent rapid developments in unmanned aerial vehicle (UAV) technology allow for the flexible generation of high-quality aerial surveying and ortho-photography at a relatively low cost.The increasing computing capabilities during the last decade, together with the development of high-performance digital sensors and the important software innovations developed by computer-based vision and visual perception research fields, have extended the rigorous processing of stereoscopic image data to a 3-D point cloud generation from a series of non-calibrated images. Structure-from-motion (SfM) workflows are based upon algorithms for efficient and automatic orientation of large image sets without further data acquisition information, examples including robust feature detectors like the scale-invariant feature transform for 2-D imagery. Nevertheless, the importance of carrying out well-established fieldwork strategies, using proper camera settings, ground control points and ground truth for understanding the different sources of errors, still needs to be adapted in the common scientific practice.This review intends not only to summarise the current state of the art on using SfM workflows in geomorphometry but also to give an overview of terms and fields of application. Furthermore, this article aims to quantify already achieved accuracies and used scales, using different strategies in order to evaluate possible stagnations of current developments and to identify key future challenges. It is our belief that some lessons learned from former articles, scientific reports and book chapters concerning the identification of common errors or "bad practices" and some other valuable information may help in guiding the future use of SfM photogrammetry in geosciences.

Quality of terrestrial data derived from UAV photogrammetry: a case study of the Hetao irrigation district in northern China

NASA Astrophysics Data System (ADS)

Zhang, Hongming; Baartman, Jantiene E. M.; Yang, Xiaomei; Gai, Lingtong; Geissen, Violette

2017-04-01

Most crops in northern China are irrigated, but the topography affects water use, soil erosion, runoff and yields,. Technologies for collecting high-resolution topographic data are essential for adequately assessing these effects. Ground surveys and techniques of light detection and ranging have good accuracy, but data acquisition can be time-consuming and expensive for large catchments. Recent rapid technological development has provided new, flexible, high-resolution methods for collecting topographic data, such as photogrammetry using unmanned aerial vehicles (UAVs). The accuracy of UAV photogrammetry for generating high-resolution digital elevation models (DEMs) and for determining the width of irrigation channels, however, has not been assessed. We used a fixed-wing UAV for collecting high-resolution (0.15 m) topographic data for the Hetao irrigation district, the third largest irrigation district in China. We surveyed 112 ground checkpoints (GCPs) using a real-time kinematic global positioning system to evaluate the accuracy of the DEMs and channel widths. A comparison of manually measured channel widths with the widths derived from the DEMs indicated that the DEM-derived widths had vertical and horizontal root mean square errors of 13.0 and 7.9 cm, respectively. UAV photogrammetric data can thus be used for land surveying, digital mapping, calculating channel capacity, monitoring crops, and predicting yields, with the advantages of economy, speed, and ease.

Time-lapse photogrammetry in geomorphic studies

NASA Astrophysics Data System (ADS)

Eltner, Anette; Kaiser, Andreas

2017-04-01

Image based approaches to reconstruct the earth surface (Structure from Motion - SfM) are establishing as a standard technology for high resolution topographic data. This is amongst other advantages due to the comparatively ease of use and flexibility of data generation. Furthermore, the increased spatial resolution led to its implementation at a vast range of applications from sub-mm to tens-of-km scale. Almost fully automatic calculation of referenced digital elevation models allows for a significant increase of temporal resolution, as well, potentially up to sub-second scales. Thereby, the setup of a time-lapse multi-camera system is necessary and different aspects need to be considered: The camera array has to be temporary stable or potential movements need to be compensated by temporary stable reference targets/areas. The stability of the internal camera geometry has to be considered due to a usually significantly lower amount of images of the scene, and thus redundancy for parameter estimation, compared to more common SfM applications. Depending on the speed of surface change, synchronisation has to be very accurate. Due to the usual application in the field, changing environmental conditions important for lighting and visual range are also crucial factors to keep in mind. Besides these important considerations much potential is comprised by time-lapse photogrammetry. The integration of multi-sensor systems, e.g. using thermal cameras, enables the potential detection of other processes not visible with RGB-images solely. Furthermore, the implementation of low-cost sensors allows for a significant increase of areal coverage and their setup at locations, where a loss of the system cannot be ruled out. The usage of micro-computers offers smart camera triggering, e.g. acquiring images with increased frequency controlled by a rainfall-triggered sensor. In addition these micro-computers can enable on-site data processing, e.g. recognition of increased surface movement, and thus might be used as warning system in the case of natural hazards. A large variety of applications are suitable with time-lapse photogrammetry, i.e. change detection of all sorts; e.g. volumetric alterations, movement tracking or roughness changes. The multi-camera systems can be used for slope investigations, soil studies, glacier observation, snow cover measurement, volcanic surveillance or plant growth monitoring. A conceptual workflow is introduced highlighting the limits and potentials of time-lapse photogrammetry.

Concepts and algorithms in digital photogrammetry

NASA Technical Reports Server (NTRS)

Schenk, T.

1994-01-01

Despite much progress in digital photogrammetry, there is still a considerable lack of understanding of theories and methods which would allow a substantial increase in the automation of photogrammetric processes. The purpose of this paper is to raise awareness that the automation problem is one that cannot be solved in a bottom-up fashion by a trial-and-error approach. We present a short overview of concepts and algorithms used in digital photogrammetry. This is followed by a more detailed presentation of perceptual organization, a typical middle-level task.

HRSC: High resolution stereo camera

USGS Publications Warehouse

Neukum, G.; Jaumann, R.; Basilevsky, A.T.; Dumke, A.; Van Gasselt, S.; Giese, B.; Hauber, E.; Head, J. W.; Heipke, C.; Hoekzema, N.; Hoffmann, H.; Greeley, R.; Gwinner, K.; Kirk, R.; Markiewicz, W.; McCord, T.B.; Michael, G.; Muller, Jan-Peter; Murray, J.B.; Oberst, J.; Pinet, P.; Pischel, R.; Roatsch, T.; Scholten, F.; Willner, K.

2009-01-01

The High Resolution Stereo Camera (HRSC) on Mars Express has delivered a wealth of image data, amounting to over 2.5 TB from the start of the mapping phase in January 2004 to September 2008. In that time, more than a third of Mars was covered at a resolution of 10-20 m/pixel in stereo and colour. After five years in orbit, HRSC is still in excellent shape, and it could continue to operate for many more years. HRSC has proven its ability to close the gap between the low-resolution Viking image data and the high-resolution Mars Orbiter Camera images, leading to a global picture of the geological evolution of Mars that is now much clearer than ever before. Derived highest-resolution terrain model data have closed major gaps and provided an unprecedented insight into the shape of the surface, which is paramount not only for surface analysis and geological interpretation, but also for combination with and analysis of data from other instruments, as well as in planning for future missions. This chapter presents the scientific output from data analysis and highlevel data processing, complemented by a summary of how the experiment is conducted by the HRSC team members working in geoscience, atmospheric science, photogrammetry and spectrophotometry. Many of these contributions have been or will be published in peer-reviewed journals and special issues. They form a cross-section of the scientific output, either by summarising the new geoscientific picture of Mars provided by HRSC or by detailing some of the topics of data analysis concerning photogrammetry, cartography and spectral data analysis.

Active retroreflector to measure the rotational orientation in conjunction with a laser tracker

NASA Astrophysics Data System (ADS)

Hofherr, O.; Wachten, C.; Müller, C.; Reinecke, H.

2012-10-01

High precision optical non-contact position measurement is a key technology in modern engineering. Laser trackers (LT) can determine accurately x-y-z coordinates of passive retroreflectors. Next-generation systems answer the additional need to measure an object's rotational orientation (pitch, yaw, roll). These devices are based on photogrammetry or on enhanced retroreflectors. However, photogrammetry relies on camera systems and time-consuming image processing. Enhanced retroreflectors analyze the LT's beam but are restricted in roll angle measurements. Here we present an integrated laser based method to evaluate all six degrees of freedom. An active retroreflector directly analyzes its orientation to the LT's beam path by outcoupling laser light on detectors. A proof of concept prototype has been designed with a specified measuring range of 360° for roll angle measurements and +/-15° for pitch and yaw angle respectively. The prototype's optical design is inspired by a cat's eye retroreflector. First results are promising and further improvements are under development. We anticipate our method to facilitate simple and cost-effective six degrees of freedom measurements. Furthermore, for industrial applications wide customizations are possible, e.g. adaptation of measuring range, optimization of accuracy, and further system miniaturization.

Photogrammetry Methodology Development for Gossamer Spacecraft Structures

NASA Technical Reports Server (NTRS)

Pappa, Richard S.; Jones, Thomas W.; Walford, Alan; Black, Jonathan T.; Robson, Stuart; Shortis, Mark R.

2002-01-01

Photogrammetry--the science of calculating 3D object coordinates from images-is a flexible and robust approach for measuring the static and dynamic characteristics of future ultralightweight and inflatable space structures (a.k.a., Gossamer structures), such as large membrane reflectors, solar sails, and thin-film solar arrays. Shape and dynamic measurements are required to validate new structural modeling techniques and corresponding analytical models for these unconventional systems. This paper summarizes experiences at NASA Langley Research Center over the past three years to develop or adapt photogrammetry methods for the specific problem of measuring Gossamer space structures. Turnkey industrial photogrammetry systems were not considered a cost-effective choice for this basic research effort because of their high purchase and maintenance costs. Instead, this research uses mainly off-the-shelf digital-camera and software technologies that are affordable to most organizations and provide acceptable accuracy.

Three-Dimensional Pathology Specimen Modeling Using "Structure-From-Motion" Photogrammetry: A Powerful New Tool for Surgical Pathology.

PubMed

Turchini, John; Buckland, Michael E; Gill, Anthony J; Battye, Shane

2018-05-30

- Three-dimensional (3D) photogrammetry is a method of image-based modeling in which data points in digital images, taken from offset viewpoints, are analyzed to generate a 3D model. This modeling technique has been widely used in the context of geomorphology and artificial imagery, but has yet to be used within the realm of anatomic pathology. - To describe the application of a 3D photogrammetry system capable of producing high-quality 3D digital models and its uses in routine surgical pathology practice as well as medical education. - We modeled specimens received in the 2 participating laboratories. The capture and photogrammetry process was automated using user control software, a digital single-lens reflex camera, and digital turntable, to generate a 3D model with the output in a PDF file. - The entity demonstrated in each specimen was well demarcated and easily identified. Adjacent normal tissue could also be easily distinguished. Colors were preserved. The concave shapes of any cystic structures or normal convex rounded structures were discernable. Surgically important regions were identifiable. - Macroscopic 3D modeling of specimens can be achieved through Structure-From-Motion photogrammetry technology and can be applied quickly and easily in routine laboratory practice. There are numerous advantages to the use of 3D photogrammetry in pathology, including improved clinicopathologic correlation for the surgeon and enhanced medical education, revolutionizing the digital pathology museum with virtual reality environments and 3D-printing specimen models.

Photogrammetry in 3d Modelling of Human Bone Structures from Radiographs

NASA Astrophysics Data System (ADS)

Hosseinian, S.; Arefi, H.

2017-05-01

Photogrammetry can have great impact on the success of medical processes for diagnosis, treatment and surgeries. Precise 3D models which can be achieved by photogrammetry improve considerably the results of orthopedic surgeries and processes. Usual 3D imaging techniques, computed tomography (CT) and magnetic resonance imaging (MRI), have some limitations such as being used only in non-weight-bearing positions, costs and high radiation dose(for CT) and limitations of MRI for patients with ferromagnetic implants or objects in their bodies. 3D reconstruction of bony structures from biplanar X-ray images is a reliable and accepted alternative for achieving accurate 3D information with low dose radiation in weight-bearing positions. The information can be obtained from multi-view radiographs by using photogrammetry. The primary step for 3D reconstruction of human bone structure from medical X-ray images is calibration which is done by applying principles of photogrammetry. After the calibration step, 3D reconstruction can be done using efficient methods with different levels of automation. Because of the different nature of X-ray images from optical images, there are distinct challenges in medical applications for calibration step of stereoradiography. In this paper, after demonstrating the general steps and principles of 3D reconstruction from X-ray images, a comparison will be done on calibration methods for 3D reconstruction from radiographs and they are assessed from photogrammetry point of view by considering various metrics such as their camera models, calibration objects, accuracy, availability, patient-friendly and cost.

Accuracy and reliability of 3D stereophotogrammetry: A comparison to direct anthropometry and 2D photogrammetry.

PubMed

Dindaroğlu, Furkan; Kutlu, Pınar; Duran, Gökhan Serhat; Görgülü, Serkan; Aslan, Erhan

2016-05-01

To evaluate the accuracy of three-dimensional (3D) stereophotogrammetry by comparing it with the direct anthropometry and digital photogrammetry methods. The reliability of 3D stereophotogrammetry was also examined. Six profile and four frontal parameters were directly measured on the faces of 80 participants. The same measurements were repeated using two-dimensional (2D) photogrammetry and 3D stereophotogrammetry (3dMDflex System, 3dMD, Atlanta, Ga) to obtain images of the subjects. Another observer made the same measurements for images obtained with 3D stereophotogrammetry, and interobserver reproducibility was evaluated for 3D images. Both observers remeasured the 3D images 1 month later, and intraobserver reproducibility was evaluated. Statistical analysis was conducted using the paired samples t-test, intraclass correlation coefficient, and Bland-Altman limits of agreement. The highest mean difference was 0.30 mm between direct measurement and photogrammetry, 0.21 mm between direct measurement and 3D stereophotogrammetry, and 0.5 mm between photogrammetry and 3D stereophotogrammetry. The lowest agreement value was 0.965 in the Sn-Pro parameter between the photogrammetry and 3D stereophotogrammetry methods. Agreement between the two observers varied from 0.90 (Ch-Ch) to 0.99 (Sn-Me) in linear measurements. For intraobserver agreement, the highest difference between means was 0.33 for observer 1 and 1.42 mm for observer 2. Measurements obtained using 3D stereophotogrammetry indicate that it may be an accurate and reliable imaging method for use in orthodontics.

Evaluation of sequential images for photogrammetrically point determination

NASA Astrophysics Data System (ADS)

Kowalczyk, M.

2011-12-01

Close range photogrammetry encounters many problems with reconstruction of objects three-dimensional shape. Relative orientation parameters of taken photos makes usually key role leading to right solution of this problem. Automation of technology process is hardly performed due to recorded scene complexity and configuration of camera positions. This configuration makes the process of joining photos into one set usually impossible automatically. Application of camcorder is the solution widely proposed in literature for support in 3D models creation. Main advantages of this tool are connected with large number of recorded images and camera positions. Exterior orientation changes barely between two neighboring frames. Those features of film sequence gives possibilities for creating models with basic algorithms, working faster and more robust, than with remotely taken photos. The first part of this paper presents results of experiments determining interior orientation parameters of some sets of frames, presenting three-dimensional test field. This section describes calibration repeatability of film frames taken from camcorder. It is important due to stability of interior camera geometric parameters. Parametric model of systematical errors was applied for correcting images. Afterwards a short film of the same test field had been taken for determination of check points group. This part has been done for controlling purposes of camera application in measurement tasks. Finally there are presented some results of experiments which compare determination of recorded object points in 3D space. In common digital photogrammetry, where separate photos are used, first levels of image pyramids are taken to connect with feature based matching. This complicated process creates a lot of emergencies, which can produce false detections of image similarities. In case of digital film camera, authors of publications avoid this dangerous step, going straightly to area based matching, aiming high degree of similarity for two corresponding film frames. First approximation, in establishing connections between photos, comes from whole image distance. This image distance method can work with more than just two dimensions of translation vector. Scale and angles are also used for improving image matching. This operation creates more similar looking frames where corresponding characteristic points lays close to each other. Procedure searching for pairs of points works faster and more accurately, because analyzed areas can be reduced. Another proposed solution comes from image created by adding differences between particular frames, gives more rough results, but works much faster than standard matching.

Some Aspects in Photogrammetry Education at the Department of Geodesy and Cadastre of the VGTU

NASA Astrophysics Data System (ADS)

Ruzgienė, Birutė

2008-03-01

The education in photogrammetry is very important when applying photogrammetric methods for the terrain mapping purposes, for spatial data modelling, solving engineering tasks, measuring of architectural monuments etc. During the time the traditional photogrammetric technologies have been changing to modern fully digital photogrammetric workflow. The number of potential users of the photogrammetric methods tends to increase, because of high-degree automation in photographs (images) processing. The main subjects in Photogrammetry (particularly in Digital Photogrammetry) educational process are discussed. Different methods and digital systems are demonstrated with the examples of aerial photogrammetry products. The main objective is to search the possibilities for training in the photogrammetric measurements. Special attention is paid to the stereo plotting from aerial photography applying modified for teaching analytical technology. The integration of functionality of Digital Photogrammetric Systems and Digital Image Processing is analysed as well with an intention of extending the application areas and possibilities for usage of modern technologies in urban mapping and land cadastre. The practical presentation of photos geometry restitution is implemented as significant part of the studies. The interactive teaching for main photogrammetric procedures and controlling systems are highly desirable that without any doubt improve the quality of educational process.

Low-Outgassing Photogrammetry Targets for Use in Outer Space

NASA Technical Reports Server (NTRS)

Gross, Jason N.; Sampler, Henry; Reed, Benjamin B.

2011-01-01

A short document discusses an investigation of materials for photogrammetry targets for highly sensitive optical scientific instruments to be operated in outer space and in an outer-space-environment- simulating thermal vacuum chamber on Earth. A key consideration in the selection of photogrammetry-target materials for vacuum environments is the need to prevent contamination that could degrade the optical responses of the instruments. Therefore, in addition to the high levels and uniformity of reflectivity required of photogrammetry-target materials suitable for use in air, the materials sought must exhibit minimal outgassing. Commercially available photogrammetry targets were found to outgas excessively under the thermal and vacuum conditions of interest; this finding prompted the investigators to consider optically equivalent or superior, lower-outgassing alternative target materials. The document lists several materials found to satisfy the requirements, but does not state explicitly whether the materials can be used individually or must be combined in the proper sequence into layered target structures. The materials in question are an aluminized polyimide tape, an acrylic pressure- sensitive adhesive, a 500-A-thick layer of vapor-deposited aluminum, and spherical barium titanate glass beads having various diameters from 20 to 63 microns..

Development of 3D Image Measurement System and Stereo-matching Method, and Its Archeological Measurement

NASA Astrophysics Data System (ADS)

Kochi, Nobuo; Ito, Tadayuki; Kitamura, Kazuo; Kaneko, Syun'ichi

The three dimensional measurement & modeling system with digital cameras on PC is now making progress and its need and hope is increasingly felt in terrestrial (close-range) photogrammetry for such sectors as cultural heritage preservation, architecture, civil engineering, manufacturing, measurement etc. Therefore, we have developed a system to improve the accuracy of stereo-matching, which is the very core of 3D measurement. As for stereo-matching method, in order to minimize the mismatching and to be robust in geometric distortions, occlusion, as well as brightness change, we invented Coarse-to-Fine Strategy Method by integrating OCM (Orientation Code Matching) with LSM (Least Squares Matching). Thus this system could attain the accuracy of 0.26mm, when we experimented on a mannequin. And when we actually experimented on the archeological ruins in Greece and Turkey, the accuracy was within the range of 1cm, compared with their blue-print plan. Besides, formally workers used to take at least 1.5 month for this kind of survey operation with the existing method, but now workers need only 3 or 4 days. Thus, its practicality and efficiency was confirmed. This paper demonstrates our new system of 3D measurement and stereo-matching with some concrete examples as its practical application.

Photogrammetric Techniques for Paleoanthropological Objects Preserving and Studying

NASA Astrophysics Data System (ADS)

Knyaz, V. A.; Leybova, N. A.; Galeev, R.; Novikov, M.; Gaboutchian, A. V.

2018-05-01

Paleo-anthropological research has its specificity closely related with studied objects. Their complicated shape arises from anatomical features of human skull and other skeletal bones. The degree of preservation is associated with the fragility of palaeo-anthropological material which usually has high historical and scientific value. The circumstances mentioned above enhance the relevance of photogrammetry implementation in anthropological studies. Thus, such combination of scientific methodologies with up-to-date technology creates a potential for improvement of various stages of palaeo-anthropological studies. This can be referred to accurate documenting of anthropological material and creation of databases accessible for wide range of users, predominantly research scientists and students; preservation of highly valuable samples and possibility of sharing information as 3D images or printed copies, improving co-operation of scientists world-wide; potential for replication of contact anthropometric studies on 3D images or printed copies providing for development of new biometric methods, and etc. This paper presents an approach based on photogrammetric techniques and non-contact measurements, providing technological and methodological development of paleo-anthropological studies, including data capturing, processing and representing.

Target-based calibration method for multifields of view measurement using multiple stereo digital image correlation systems

NASA Astrophysics Data System (ADS)

Dong, Shuai; Yu, Shanshan; Huang, Zheng; Song, Shoutan; Shao, Xinxing; Kang, Xin; He, Xiaoyuan

2017-12-01

Multiple digital image correlation (DIC) systems can enlarge the measurement field without losing effective resolution in the area of interest (AOI). However, the results calculated in substereo DIC systems are located in its local coordinate system in most cases. To stitch the data obtained by each individual system, a data merging algorithm is presented in this paper for global measurement of multiple stereo DIC systems. A set of encoded targets is employed to assist the extrinsic calibration, of which the three-dimensional (3-D) coordinates are reconstructed via digital close range photogrammetry. Combining the 3-D targets with precalibrated intrinsic parameters of all cameras, the extrinsic calibration is significantly simplified. After calculating in substereo DIC systems, all data can be merged into a universal coordinate system based on the extrinsic calibration. Four stereo DIC systems are applied to a four point bending experiment of a steel reinforced concrete beam structure. Results demonstrate high accuracy for the displacement data merging in the overlapping field of views (FOVs) and show feasibility for the distributed FOVs measurement.

An Experience in Cultural Heritage Documentation in Iran Using a Low-Cost Technique

NASA Astrophysics Data System (ADS)

Hassani, F.; Rafiee, M.

2013-07-01

Today, the need for preservation of cultural heritage as an important, irreplaceable resource for human is well recognized. In this regard, prior to any conservational measure, detailed documentation and recording of these precious resources should be performed; since this way, not only preservation requirements of the object will be identified, but also the existing condition will be recorded for future generations. Accordingly, since Iran is known as an ancient land possesses valuable historic resources, and due the numerousness of Iran's monuments and the high possibility of occurring natural disasters which are counted as significant threats for the monuments, the necessity of fast and appropriate documentation in this country will be clarified. This paper is in fact a part of the project entitled "Study of the application of digital technologies in recording and rehabilitation of historic buildings" in Iran. Here, the surveying process of aforesaid project's case study which is one of the two Kharraqan Tomb Towers placed in Qazvin province of Iran, using close range photogrammetry and low cost equipment will be demonstrated.

Epic Dimensions: a Comparative Analysis of 3d Acquisition Methods

NASA Astrophysics Data System (ADS)

Graham, C. A.; Akoglu, K. G.; Lassen, A. W.; Simon, S.

2017-08-01

When it comes to capturing the geometry of a cultural heritage artifact, there is certainly no dearth of possible acquisition techniques. As technology has rapidly developed, the availability of intuitive 3D generating tools has increased exponentially and made it possible even for non-specialists to create many models quickly. Though the by-products of these different acquisition methods may be incongruent in terms of quality, these discrepancies are not problematic, as there are many applications of 3D models, each with their own set of requirements. Comparisons of high-resolution 3D models of an iconic Babylonian tablet, captured via four different closerange technologies discussed in this paper assess which methods of 3D digitization best suit specific intended purposes related to research, conservation and education. Taking into consideration repeatability, time and resource implications, qualitative and quantitative potential and ease of use, this paper presents a study of the strengths and weakness of structured light scanning, triangulation laser scanning, photometric stereo and close-range photogrammetry, in the context of interactive investigation, conditions monitoring, engagement, and dissemination.

Study on portable optical 3D coordinate measuring system

NASA Astrophysics Data System (ADS)

Ren, Tongqun; Zhu, Jigui; Guo, Yinbiao

2009-05-01

A portable optical 3D coordinate measuring system based on digital Close Range Photogrammetry (CRP) technology and binocular stereo vision theory is researched. Three ultra-red LED with high stability is set on a hand-hold target to provide measuring feature and establish target coordinate system. Ray intersection based field directional calibrating is done for the intersectant binocular measurement system composed of two cameras by a reference ruler. The hand-hold target controlled by Bluetooth wireless communication is free moved to implement contact measurement. The position of ceramic contact ball is pre-calibrated accurately. The coordinates of target feature points are obtained by binocular stereo vision model from the stereo images pair taken by cameras. Combining radius compensation for contact ball and residual error correction, object point can be resolved by transfer of axes using target coordinate system as intermediary. This system is suitable for on-field large-scale measurement because of its excellent portability, high precision, wide measuring volume, great adaptability and satisfying automatization. It is tested that the measuring precision is near to +/-0.1mm/m.

Photogrammetry of the Map Instrument in a Cryogenic Vacuum Environment

NASA Technical Reports Server (NTRS)

Hill, M.; Packard, E.; Pazar, R.

2000-01-01

MAP Instrument requirements dictated that the instruments Focal Plane Assembly (FPA) and Thermal Reflector System (TRS) maintain a high degree of structural integrity at operational temperatures (< 50K). To verify integrity at these extremes, an elaborate test fixture was constructed to provide a large cryogenic (< 20K) radiative environment and a mobile photogrammetry camera. This paper will discuss MAP's Instrument requirements, how those requirements were verified using photogrammetry, and the test setup used to provide the environment and camera movement needed to verify the instrument's requirements.

Comparing the Use of 3D Photogrammetry and Computed Tomography in Assessing the Severity of Single-Suture Nonsyndromic Craniosynostosis

PubMed Central

Ho, Olivia A.; Saber, Nikoo; Stephens, Derek; Clausen, April; Drake, James; Forrest, Christopher

2017-01-01

Purpose: Single-suture nonsyndromic craniosynostosis is diagnosed using clinical assessment and computed tomography (CT). With increasing awareness of the associated risks of radiation exposure, the use of CT is particularly concerning in patients with craniosynostosis since they are exposed at a younger age and more frequently than the average child. Three-dimensional (3D) photogrammetry is advantageous—it involves no radiation, is conveniently obtainable within clinic, and does not require general anaesthesia. This study aims to assess how 3D photogrammetry compares to CT in the assessment of craniosynostosis severity, to quantify surgical outcomes, and analyze the validity of 3D photogrammetry in craniosynostosis. Methods: Computed tomography images and 3D photographs of patients who underwent craniosynostosis surgery were assessed and aligned to best fit. The intervening area between the CT and 3D photogrammetry curves at the supraorbital bar (bandeau) level in axial view was calculated. Statistical analysis was performed using Student t test. Ninety-five percent confidence intervals were determined and equivalence margins were applied. Results: In total, 41 pairs of CTs and 3D photographs were analyzed. The 95% confidence interval was 198.16 to 264.18 mm2 and the mean was 231.17 mm2. When comparisons were made in the same bandeau region omitting the temporalis muscle, the 95% confidence interval was 108.94 to 147.38 mm2, and the mean was 128.16 mm2. Although statistically significant difference between the modalities was found, they can be attributable to the dampening effect of soft tissue. Conclusion: Within certain error margins, 3D photogrammetry is comparable to CT in assessing the severity of single-suture nonsyndromic craniosynostosis. However, a dampening effect can be attributable to the soft tissue. Three-dimensional photogrammetry may be more applicable for severe cases of craniosynostosis but not milder deformity. It may also be beneficial for assessing the overall appearance and aesthetics but not for determining underlying bony severity. PMID:29026817

Comparing the Use of 3D Photogrammetry and Computed Tomography in Assessing the Severity of Single-Suture Nonsyndromic Craniosynostosis.

PubMed

Ho, Olivia A; Saber, Nikoo; Stephens, Derek; Clausen, April; Drake, James; Forrest, Christopher; Phillips, John

2017-05-01

Single-suture nonsyndromic craniosynostosis is diagnosed using clinical assessment and computed tomography (CT). With increasing awareness of the associated risks of radiation exposure, the use of CT is particularly concerning in patients with craniosynostosis since they are exposed at a younger age and more frequently than the average child. Three-dimensional (3D) photogrammetry is advantageous-it involves no radiation, is conveniently obtainable within clinic, and does not require general anaesthesia. This study aims to assess how 3D photogrammetry compares to CT in the assessment of craniosynostosis severity, to quantify surgical outcomes, and analyze the validity of 3D photogrammetry in craniosynostosis. Computed tomography images and 3D photographs of patients who underwent craniosynostosis surgery were assessed and aligned to best fit. The intervening area between the CT and 3D photogrammetry curves at the supraorbital bar (bandeau) level in axial view was calculated. Statistical analysis was performed using Student t test. Ninety-five percent confidence intervals were determined and equivalence margins were applied. In total, 41 pairs of CTs and 3D photographs were analyzed. The 95% confidence interval was 198.16 to 264.18 mm 2 and the mean was 231.17 mm 2 . When comparisons were made in the same bandeau region omitting the temporalis muscle, the 95% confidence interval was 108.94 to 147.38 mm 2 , and the mean was 128.16 mm 2 . Although statistically significant difference between the modalities was found, they can be attributable to the dampening effect of soft tissue. Within certain error margins, 3D photogrammetry is comparable to CT in assessing the severity of single-suture nonsyndromic craniosynostosis. However, a dampening effect can be attributable to the soft tissue. Three-dimensional photogrammetry may be more applicable for severe cases of craniosynostosis but not milder deformity. It may also be beneficial for assessing the overall appearance and aesthetics but not for determining underlying bony severity.

Mapping the Campus.

ERIC Educational Resources Information Center

Stigner, Kenneth J.

2001-01-01

Discusses how aerial photography and photogrammetry technology can help schools create visual records of their campus, land, and properties. Addresses efficiency and cost effectiveness of this method. Discusses how to develop the digital photogrammetry method for mapping from aerial photos. (GR)

Photogrammetry and optical methods in structural dynamics - A review

NASA Astrophysics Data System (ADS)

Baqersad, Javad; Poozesh, Peyman; Niezrecki, Christopher; Avitabile, Peter

2017-03-01

In the last few decades, there has been a surge of research in the area of non-contact measurement techniques. Photogrammetry has received considerable attention due to its ability to achieve full-field measurement and its robustness to work in testing environments and on testing articles in which using other measurement techniques may not be practical. More recently, researchers have used this technique to study transient phenomena and to perform measurements on vibrating structures. The current paper reviews the most current trends in the photogrammetry technique (point tracking, digital image correlation, and target-less approaches) and compares the applications of photogrammetry to other measurement techniques used in structural dynamics (e.g. laser Doppler vibrometry and interferometry techniques). The paper does not present the theoretical background of the optical techniques, but instead presents the general principles of each approach and highlights the novel structural dynamic measurement concepts and applications that are enhanced by utilizing optical techniques.

The Combination of Spherical Photogrammetry and UAV for 3D Modeling

NASA Astrophysics Data System (ADS)

Ihsanudin, T.; Affriani, A. R.

2017-12-01

The complete of 3D models required the object that was recorded from both side and top. If the object recorded from above, then the object from the side can not be covered, and if the objects recorded from the side, it can not be covered from the top. Recording of objects from the side using spherical photogrammetry method and from the top using UAV method. The merge of both models using a conform transformation, by bringing the spherical photogrammetry coordinates system to the UAV model. The object of this research is Ratu Boko temple, Sleman, Yogyakarta. The spherical photogrammetry recording was performed by rotating the camera in 360° angle on the entire area of the temple. The area consists of 12 stations. The UAV method uses a drone with flight attitude of 20 meters. The merge of the both models produced the completeness of the temple model from the top and side.

Pathfinder Photogrammetry Research for Ultra-Lightweight and Inflatable Space Structures

NASA Technical Reports Server (NTRS)

Giersch, Louis Roy Miller

2001-01-01

The defining characteristic of ultra-lightweight and inflatable space structures is that they are both very large and very low mass. This makes standard contacting methods of measurement (e.g. attaching accelerometers) impractical because the dynamics of the structure would be changed by the mass of the contacting instrument. Optical measurements are therefore more appropriate. Photogrammetry is a leading candidate for the optical analysis of gossamer structures because it allows for the measurement of a large number of points, is amenable to time sequences, and offers the potential for a high degree of accuracy. The purpose of this thesis is to develop the methodology and determine the effectiveness of a photogrammetry system in measuring ultra-lightweight and inflatable space structures. The results of this thesis will be considered in the design of an automated photogrammetry system for the l6m-diameter vacuum chamber at the NASA Langley Research Center.

Study of 3D bathymetry modelling using LAPAN Surveillance Unmanned Aerial Vehicle 02 (LSU-02) photo data with stereo photogrammetry technique, Wawaran Beach, Pacitan, East Java, Indonesia

NASA Astrophysics Data System (ADS)

Sari, N. M.; Nugroho, J. T.; Chulafak, G. A.; Kushardono, D.

2018-05-01

Coastal is an ecosystem that has unique object and phenomenon. The potential of the aerial photo data with very high spatial resolution covering coastal area is extensive. One of the aerial photo data can be used is LAPAN Surveillance UAV 02 (LSU-02) photo data which is acquired in 2016 with a spatial resolution reaching 10cm. This research aims to create an initial bathymetry model with stereo photogrammetry technique using LSU-02 data. In this research the bathymetry model was made by constructing 3D model with stereo photogrammetry technique that utilizes the dense point cloud created from overlapping of those photos. The result shows that the 3D bathymetry model can be built with stereo photogrammetry technique. It can be seen from the surface and bathymetry transect profile.

Photogrammetry Methodology Development for Gossamer Spacecraft Structures

NASA Technical Reports Server (NTRS)

Pappa, Richard S.; Jones, Thomas W.; Black, Jonathan T.; Walford, Alan; Robson, Stuart; Shortis, Mark R.

2002-01-01

Photogrammetry--the science of calculating 3D object coordinates from images--is a flexible and robust approach for measuring the static and dynamic characteristics of future ultra-lightweight and inflatable space structures (a.k.a., Gossamer structures), such as large membrane reflectors, solar sails, and thin-film solar arrays. Shape and dynamic measurements are required to validate new structural modeling techniques and corresponding analytical models for these unconventional systems. This paper summarizes experiences at NASA Langley Research Center over the past three years to develop or adapt photogrammetry methods for the specific problem of measuring Gossamer space structures. Turnkey industrial photogrammetry systems were not considered a cost-effective choice for this basic research effort because of their high purchase and maintenance costs. Instead, this research uses mainly off-the-shelf digital-camera and software technologies that are affordable to most organizations and provide acceptable accuracy.

Digital stereo photogrammetry for grain-scale monitoring of fluvial surfaces: Error evaluation and workflow optimisation

NASA Astrophysics Data System (ADS)

Bertin, Stephane; Friedrich, Heide; Delmas, Patrice; Chan, Edwin; Gimel'farb, Georgy

2015-03-01

Grain-scale monitoring of fluvial morphology is important for the evaluation of river system dynamics. Significant progress in remote sensing and computer performance allows rapid high-resolution data acquisition, however, applications in fluvial environments remain challenging. Even in a controlled environment, such as a laboratory, the extensive acquisition workflow is prone to the propagation of errors in digital elevation models (DEMs). This is valid for both of the common surface recording techniques: digital stereo photogrammetry and terrestrial laser scanning (TLS). The optimisation of the acquisition process, an effective way to reduce the occurrence of errors, is generally limited by the use of commercial software. Therefore, the removal of evident blunders during post processing is regarded as standard practice, although this may introduce new errors. This paper presents a detailed evaluation of a digital stereo-photogrammetric workflow developed for fluvial hydraulic applications. The introduced workflow is user-friendly and can be adapted to various close-range measurements: imagery is acquired with two Nikon D5100 cameras and processed using non-proprietary "on-the-job" calibration and dense scanline-based stereo matching algorithms. Novel ground truth evaluation studies were designed to identify the DEM errors, which resulted from a combination of calibration errors, inaccurate image rectifications and stereo-matching errors. To ensure optimum DEM quality, we show that systematic DEM errors must be minimised by ensuring a good distribution of control points throughout the image format during calibration. DEM quality is then largely dependent on the imagery utilised. We evaluated the open access multi-scale Retinex algorithm to facilitate the stereo matching, and quantified its influence on DEM quality. Occlusions, inherent to any roughness element, are still a major limiting factor to DEM accuracy. We show that a careful selection of the camera-to-object and baseline distance reduces errors in occluded areas and that realistic ground truths help to quantify those errors.

Developments in analytical instrumentation

NASA Astrophysics Data System (ADS)

Petrie, G.

The situation regarding photogrammetric instrumentation has changed quite dramatically over the last 2 or 3 years with the withdrawal of most analogue stereo-plotting machines from the market place and their replacement by analytically based instrumentation. While there have been few new developments in the field of comparators, there has been an explosive development in the area of small, relatively inexpensive analytical stereo-plotters based on the use of microcomputers. In particular, a number of new instruments have been introduced by manufacturers who mostly have not been associated previously with photogrammetry. Several innovative concepts have been introduced in these small but capable instruments, many of which are aimed at specialised applications, e.g. in close-range photogrammetry (using small-format cameras); for thematic mapping (by organisations engaged in environmental monitoring or resources exploitation); for map revision, etc. Another innovative and possibly significant development has been the production of conversion kits to convert suitable analogue stereo-plotting machines such as the Topocart, PG-2 and B-8 into fully fledged analytical plotters. The larger and more sophisticated analytical stereo-plotters are mostly being produced by the traditional mainstream photogrammetric systems suppliers with several new instruments and developments being introduced at the top end of the market. These include the use of enlarged photo stages to handle images up to 25 × 50 cm format; the complete integration of graphics workstations into the analytical plotter design; the introduction of graphics superimposition and stereo-superimposition; the addition of correlators for the automatic measurement of height, etc. The software associated with this new analytical instrumentation is now undergoing extensive re-development with the need to supply photogrammetric data as input to the more sophisticated G.I.S. systems now being installed by clients, instead of the data being used mostly in the digital mapping systems operated in-house by mapping organisations. These various new hardware and software developments are reported upon and analysed in this Invited Paper presented to ISPRS Commission II at the 1988 Kyoto Congress.

Multiscale Documentation and Monitoring of L'aquila Historical Centre Using Uav Photogrammetry

NASA Astrophysics Data System (ADS)

Dominici, D.; Alicandro, M.; Rosciano, E.; Massimi, V.

2017-05-01

Nowadays geomatic techniques can guarantee not only a precise and accurate survey for the documentation of our historical heritage but also a solution to monitor its behaviour over time after, for example, a catastrophic event (earthquakes, landslides, ecc). Europe is trying to move towards harmonized actions to store information on cultural heritage (MIBAC with the ICCS forms, English heritage with the MIDAS scheme, etc) but it would be important to provide standardized methods in order to perform measuring operations to collect certified metric data. The final result could be a database to support the entire management of the cultural heritage and also a checklist of "what to do" and "when to do it". The wide range of geomatic techniques provides many solutions to acquire, to organize and to manage data at a multiscale level: high resolution satellite images can provide information in a short time during the "early emergency" while UAV photogrammetry and laser scanning can provide digital high resolution 3D models of buildings, ortophotos of roofs and facades and so on. This paper presents some multiscale survey case studies using UAV photogrammetry: from a minor historical village (Aielli) to the centre of L'Aquila (Santa Maria di Collemaggio Church) from the post-emergency to now. This choice has been taken not only to present how geomatics is an effective science for modelling but also to present a complete and reliable way to perform conservation and/or restoration through precise monitoring techniques, as shown in the third case study.

Experiment on Uav Photogrammetry and Terrestrial Laser Scanning for Ict-Integrated Construction

NASA Astrophysics Data System (ADS)

Takahashi, N.; Wakutsu, R.; Kato, T.; Wakaizumi, T.; Ooishi, T.; Matsuoka, R.

2017-08-01

In the 2016 fiscal year the Ministry of Land, Infrastructure, Transport and Tourism of Japan started a program integrating construction and ICT in earthwork and concrete placing. The new program named "i-Construction" focusing on productivity improvement adopts such new technologies as UAV photogrammetry and TLS. We report a field experiment to investigate whether the procedures of UAV photogrammetry and TLS following the standards for "i-Construction" are feasible or not. In the experiment we measured an embankment of about 80 metres by 160 metres immediately after earthwork was done on the embankment. We used two sets of UAV and camera in the experiment. One is a larger UAV enRoute Zion QC730 and its onboard camera Sony α6000. The other is a smaller UAV DJI Phantom 4 and its dedicated onboard camera. Moreover, we used a terrestrial laser scanner FARO Focus3D X330 based on the phase shift principle. The experiment results indicate that the procedures of UAV photogrammetry using a QC730 with an α6000 and TLS using a Focus3D X330 following the standards for "i-Construction" would be feasible. Furthermore, the experiment results show that UAV photogrammetry using a lower price UAV Phantom 4 was unable to satisfy the accuracy requirement for "i-Construction." The cause of the low accuracy by Phantom 4 is under investigation. We also found that the difference of image resolution on the ground would not have a great influence on the measurement accuracy in UAV photogrammetry.

Optical Strain Measurement of an Inflated Cylinder using Photogrammetry with Application to Scientific Balloons

NASA Technical Reports Server (NTRS)

Blandino, Joseph R.; Sterling, Jerry; Baginski, Frank; Steadman, Eric; Black, Jonathan T.; Pappa, Richard S.

2004-01-01

A study is presented using photogrammetry to measure the biaxial strain in an inflated cylinder. Two cylinders constructed from polyethylene and each approximately 222 mm in diameter and 930 mm in length were studied. The first had a 0.038 mm wall thickness while the second had a 0.02 mm wall thickness. The cylinders were inflated to a maximum pressure of 1379 Pa. The strain was determined from data collected from 60 retro-reflective targets arranged in a 12 x 5 grid. The uncertainty of the measurement system was determined to be 0.08, 0.04 and 0.06 mm in the x, y, and z directions respectively. The hoop and meridional strains determined from displacement data were compared to values obtained from a finite element analysis of a related proxy problem. The predicted hoop strains showed good agreement over the entire range of pressures while the meridional strains showed good agreement at the lower pressures.

Photogrammetry of the solar aureole

NASA Technical Reports Server (NTRS)

Deepak, A.

1978-01-01

This paper presents a photogrammetric analysis of the solar aureole for the purpose of making photographic sky radiance measurements for determining aerosol physical characteristics. A photograph is essentially a projection of a 3-D object space onto a 2-D image space. Photogrammetry deals with relations that exist between the object and the image spaces. The main problem of photogrammetry is the reconstruction of configurations in the object space by means of the image space data. It is shown that the almucantar projects onto the photographic plane as a conic section and the sun vertical as a straight line.

Intratarsal fixation at the same level as the skin incision to reduce asymmetric double eyelids: evaluation of symmetry using photogrammetry.

PubMed

Han, Kihwan; Yeo, Hyeonjung; Choi, Tae Hyun; Son, Daegu; Kim, Jun Hyung

2010-03-01

One of the most common complications of double eyelid operations is asymmetry. To reduce asymmetry, we fixed the dermis to the tarsal plate at the same level as the skin incision, and objectively evaluated the symmetry of the height using photogrammetry.Of 30 patients who had double eyelid operations by the intratarsal fixation technique, 15 patients completed a minimum follow-up of 6 months. After the skin incision and removal of the orbicularis oculi muscle and the orbital fat, the pretarsal fat pad was excised to expose the superior portion of the tarsal plate. The 3 fixation points were marked on the tarsal plate at the same level with the skin incision using a spreading caliper. The dermis was fixed to the marked points of the tarsal plate and the skin was closed.The height of the double eyelid was measured by clinical photography at 4 points when the eyes were opened and at 3 points when the eyes were closed. The height proportional index at each point was obtained by dividing the height of the left double eyelid by that of the right double eyelid. We compared each height proportional index with "1" to evaluate the symmetry of both double eyelids using a paired t test.The follow-up period was an average of 9.0 months. The mean height proportional indices were 0.97 (a), 0.96 (b), 0.98 (c), 1.08 (d), 0.97 (e), 1.02 (f), and 1.13 (g). According to a paired t test, the height of the left double eyelid was not different from that of the right double eyelid.Intratarsal fixation, along with other previously known methods, decreases asymmetric double eyelids.

Photogrammetry Tool for Forensic Analysis

NASA Technical Reports Server (NTRS)

Lane, John

2012-01-01

A system allows crime scene and accident scene investigators the ability to acquire visual scene data using cameras for processing at a later time. This system uses a COTS digital camera, a photogrammetry calibration cube, and 3D photogrammetry processing software. In a previous instrument developed by NASA, the laser scaling device made use of parallel laser beams to provide a photogrammetry solution in 2D. This device and associated software work well under certain conditions. In order to make use of a full 3D photogrammetry system, a different approach was needed. When using multiple cubes, whose locations relative to each other are unknown, a procedure that would merge the data from each cube would be as follows: 1. One marks a reference point on cube 1, then marks points on cube 2 as unknowns. This locates cube 2 in cube 1 s coordinate system. 2. One marks reference points on cube 2, then marks points on cube 1 as unknowns. This locates cube 1 in cube 2 s coordinate system. 3. This procedure is continued for all combinations of cubes. 4. The coordinate of all of the found coordinate systems is then merged into a single global coordinate system. In order to achieve maximum accuracy, measurements are done in one of two ways, depending on scale: when measuring the size of objects, the coordinate system corresponding to the nearest cube is used, or when measuring the location of objects relative to a global coordinate system, a merged coordinate system is used. Presently, traffic accident analysis is time-consuming and not very accurate. Using cubes with differential GPS would give absolute positions of cubes in the accident area, so that individual cubes would provide local photogrammetry calibration to objects near a cube.

Application of terrestrial 'structure-from-motion' photogrammetry on a medium-size Arctic valley glacier: potential, accuracy and limitations

NASA Astrophysics Data System (ADS)

Hynek, Bernhard; Binder, Daniel; Boffi, Geo; Schöner, Wolfgang; Verhoeven, Geert

2014-05-01

Terrestrial photogrammetry was the standard method for mapping high mountain terrain in the early days of mountain cartography, until it was replaced by aerial photogrammetry and airborne laser scanning. Modern low-price digital single-lens reflex (DSLR) cameras and highly automatic and cheap digital computer vision software with automatic image matching and multiview-stereo routines suggest the rebirth of terrestrial photogrammetry, especially in remote regions, where airborne surveying methods are expensive due to high flight costs. Terrestrial photogrammetry and modern automated image matching is widely used in geodesy, however, its application in glaciology is still rare, especially for surveying ice bodies at the scale of some km², which is typical for valley glaciers. In August 2013 a terrestrial photogrammetric survey was carried out on Freya Glacier, a 6km² valley glacier next to Zackenberg Research Station in NE-Greenland, where a detailed glacier mass balance monitoring was initiated during the last IPY. Photos with a consumer grade digital camera (Nikon D7100) were taken from the ridges surrounding the glacier. To create a digital elevation model, the photos were processed with the software photoscan. A set of ~100 dGPS surveyed ground control points on the glacier surface was used to georeference and validate the final DEM. Aim of this study was to produce a high resolution and high accuracy DEM of the actual surface topography of the Freya glacier catchment with a novel approach and to explore the potential of modern low-cost terrestrial photogrammetry combined with state-of-the-art automated image matching and multiview-stereo routines for glacier monitoring and to communicate this powerful and cheap method within the environmental research and glacier monitoring community.

Volume measurements on three-dimensional photogrammetry after extended strip versus total cranial remodeling for sagittal synostosis: A comparative cohort study.

PubMed

van Veelen, Marie-Lise C; Jippes, Marielle; Carolina, Julius-Carl A; de Rooi, Johan; Dirven, Clemens M F; van Adrichem, Leon N A; Mathijssen, Irene M

2016-10-01

Surgery for sagittal synostosis aims at correction of skull shape and restoration of growth potential. Small cranial volume is associated with raised intracranial pressure (ICP). Although many techniques have been described, information on postoperative volume related to early and late remodeling is lacking. Between 2004 and 2008, a total of 95 patients were collected who underwent either early extended strip craniectomy or late total cranial remodeling according to age of presentation. Volume was measured on three-dimensional (3D) photogrammetry. Volume measurements were related to cranial index (CI), head circumference (HCsd), and signs of raised ICP. In a small subset of patients, volume measurements on 3D photogrammetry were assessed for inter- and intrarater reliability and compared to 3D computed tomography (CT). Volume was increased in all patients before and after surgery compared to normative values. Postoperatively, late total cranial remodeling resulted in a slightly larger volume than early extended strip craniectomy. Volume measurements showed a good correlation with HCsd (0.67) and a poor relationship with CI (0.13). Headache occurred more frequently in patients with a lower cranial volume. Although papilledema and reoperation showed the same trend, the numbers were too small for statistical analysis. Reproducibility of volume measurements on 3D photogrammetry was high, as was the correlation with measurements on CT. Late total cranial remodeling results in a larger postoperative volume, as measured on 3D photogrammetry, than extended strip craniectomy. Clinical signs of raised ICP occur more frequently in patients with a smaller volume. To measure volume, 3D photogrammetry is a good alternative to CT. Copyright © 2016. Published by Elsevier Ltd.

Theme issue ;State-of-the-art in photogrammetry, remote sensing and spatial information science;

NASA Astrophysics Data System (ADS)

Heipke, Christian; Madden, Marguerite; Li, Zhilin; Dowman, Ian

2016-05-01

Over the past few years, photogrammetry, remote sensing and spatial information science have witnessed great changes in virtually every stage of information from imagery. Indeed, we have seen, for example, a sharply increased interest in unmanned aerial vehicles,

Verification of micro-scale photogrammetry for smooth three-dimensional object measurement

NASA Astrophysics Data System (ADS)

Sims-Waterhouse, Danny; Piano, Samanta; Leach, Richard

2017-05-01

By using sub-millimetre laser speckle pattern projection we show that photogrammetry systems are able to measure smooth three-dimensional objects with surface height deviations less than 1 μm. The projection of laser speckle patterns allows correspondences on the surface of smooth spheres to be found, and as a result, verification artefacts with low surface height deviations were measured. A combination of VDI/VDE and ISO standards were also utilised to provide a complete verification method, and determine the quality parameters for the system under test. Using the proposed method applied to a photogrammetry system, a 5 mm radius sphere was measured with an expanded uncertainty of 8.5 μm for sizing errors, and 16.6 μm for form errors with a 95 % confidence interval. Sphere spacing lengths between 6 mm and 10 mm were also measured by the photogrammetry system, and were found to have expanded uncertainties of around 20 μm with a 95 % confidence interval.

Field Accuracy Test of Rpas Photogrammetry

NASA Astrophysics Data System (ADS)

Barry, P.; Coakley, R.

2013-08-01

Baseline Surveys Ltd is a company which specialises in the supply of accurate geospatial data, such as cadastral, topographic and engineering survey data to commercial and government bodies. Baseline Surveys Ltd invested in aerial drone photogrammetric technology and had a requirement to establish the spatial accuracy of the geographic data derived from our unmanned aerial vehicle (UAV) photogrammetry before marketing our new aerial mapping service. Having supplied the construction industry with survey data for over 20 years, we felt that is was crucial for our clients to clearly understand the accuracy of our photogrammetry so they can safely make informed spatial decisions, within the known accuracy limitations of our data. This information would also inform us on how and where UAV photogrammetry can be utilised. What we wanted to find out was the actual accuracy that can be reliably achieved using a UAV to collect data under field conditions throughout a 2 Ha site. We flew a UAV over the test area in a "lawnmower track" pattern with an 80% front and 80% side overlap; we placed 45 ground markers as check points and surveyed them in using network Real Time Kinematic Global Positioning System (RTK GPS). We specifically designed the ground markers to meet our accuracy needs. We established 10 separate ground markers as control points and inputted these into our photo modelling software, Agisoft PhotoScan. The remaining GPS coordinated check point data were added later in ArcMap to the completed orthomosaic and digital elevation model so we could accurately compare the UAV photogrammetry XYZ data with the RTK GPS XYZ data at highly reliable common points. The accuracy we achieved throughout the 45 check points was 95% reliably within 41 mm horizontally and 68 mm vertically and with an 11.7 mm ground sample distance taken from a flight altitude above ground level of 90 m.The area covered by one image was 70.2 m × 46.4 m, which equals 0.325 Ha. This finding has shown that XYZ data derived from UAV photogrammetry has a similar practical accuracy to RTK GPS, which is commonly used for cadastral, topographic and engineering survey work. This means that UAV photogrammetry can, for the most part, replace GPS surveying as the main method of data capture for engineering projects, boundary mapping and topographical surveying. Aerial Photogrammetry, in conjunction with RTK GPS, can now be used for projects with a 1:200 map scale accuracy requirement.

Mapping snow depth in complex alpine terrain with close range aerial imagery - estimating the spatial uncertainties of repeat autonomous aerial surveys over an active rock glacier

NASA Astrophysics Data System (ADS)

Goetz, Jason; Marcer, Marco; Bodin, Xavier; Brenning, Alexander

2017-04-01

Snow depth mapping in open areas using close range aerial imagery is just one of the many cases where developments in structure-from-motion and multi-view-stereo (SfM-MVS) 3D reconstruction techniques have been applied for geosciences - and with good reason. Our ability to increase the spatial resolution and frequency of observations may allow us to improve our understanding of how snow depth distribution varies through space and time. However, to ensure accurate snow depth observations from close range sensing we must adequately characterize the uncertainty related to our measurement techniques. In this study, we explore the spatial uncertainties of snow elevation models for estimation of snow depth in a complex alpine terrain from close range aerial imagery. We accomplish this by conducting repeat autonomous aerial surveys over a snow-covered active-rock glacier located in the French Alps. The imagery obtained from each flight of an unmanned aerial vehicle (UAV) is used to create an individual digital elevation model (DEM) of the snow surface. As result, we obtain multiple DEMs of the snow surface for the same site. These DEMs are obtained from processing the imagery with the photogrammetry software Agisoft Photoscan. The elevation models are also georeferenced within Photoscan using the geotagged imagery from an onboard GNSS in combination with ground targets placed around the rock glacier, which have been surveyed with highly accurate RTK-GNSS equipment. The random error associated with multi-temporal DEMs of the snow surface is estimated from the repeat aerial survey data. The multiple flights are designed to follow the same flight path and altitude above the ground to simulate the optimal conditions of repeat survey of the site, and thus try to estimate the maximum precision associated with our snow-elevation measurement technique. The bias of the DEMs is assessed with RTK-GNSS survey observations of the snow surface elevation of the area on and surrounding the rock glacier. Additionally, one of the challenges with processing snow cover imagery with SfM-MVS is dealing with the general homogeneity of the surface, which makes is difficult for automated-feature detection algorithms to identify key features for point matching. This challenge depends on the snow cover surface conditions, such as scale, lighting conditions (high vs. low contrast), and availability of snow-free features within a scene, among others. We attempt to explore this aspect by spatial modelling the factors influencing the precision and bias of the DEMs from image, flight, and terrain attributes.

Three-dimensional photography for the evaluation of facial profiles in obstructive sleep apnoea.

PubMed

Lin, Shih-Wei; Sutherland, Kate; Liao, Yu-Fang; Cistulli, Peter A; Chuang, Li-Pang; Chou, Yu-Ting; Chang, Chih-Hao; Lee, Chung-Shu; Li, Li-Fu; Chen, Ning-Hung

2018-06-01

Craniofacial structure is an important determinant of obstructive sleep apnoea (OSA) syndrome risk. Three-dimensional stereo-photogrammetry (3dMD) is a novel technique which allows quantification of the craniofacial profile. This study compares the facial images of OSA patients captured by 3dMD to three-dimensional computed tomography (3-D CT) and two-dimensional (2-D) digital photogrammetry. Measurements were correlated with indices of OSA severity. Thirty-eight patients diagnosed with OSA were included, and digital photogrammetry, 3dMD and 3-D CT were performed. Distances, areas, angles and volumes from the images captured by three methods were analysed. Almost all measurements captured by 3dMD showed strong agreement with 3-D CT measurements. Results from 2-D digital photogrammetry showed poor agreement with 3-D CT. Mandibular width, neck perimeter size and maxillary volume measurements correlated well with the severity of OSA using all three imaging methods. Mandibular length, facial width, binocular width, neck width, cranial base triangle area, cranial base area 1 and middle cranial fossa volume correlated well with OSA severity using 3dMD and 3-D CT, but not with 2-D digital photogrammetry. 3dMD provided accurate craniofacial measurements of OSA patients, which were highly concordant with those obtained by CT, while avoiding the radiation associated with CT. © 2018 Asian Pacific Society of Respirology.

Geomorphological processes in a semiarid badland area using new technologies: TLS, terrestrial and aerial SfM photogrammetry

NASA Astrophysics Data System (ADS)

Ferrer, Victor; Errea, Paz; Alonso, Esteban; Gómez-Gutiérrez, Álvaro; Nadal-Romero, Estela

2017-04-01

We used three different methods Terrestrial Laser Scanner (TLS), terrestrial Structure from Motion photogrammetry (SfM) and aerial SfM photogrammetry with an Unmanned Aerial Vehicle (UAV) to analyse geomorphological processes in a semiarid badland landscape. Los Aguarales badlands, located in the Ebro Depression (Spain), occur in the Holocene sediment accumulated in a wide valley infilled with silt and clay. The morphology of Los Aguarales badlands is complex, making the geomorphological interpretation a difficult task. Los Aguarales badlands are characterized by the sequence of incision and piping processes developing an abrupt and complex landscape. Three different representative and small study sites were selected to carry out a detailed analysis of the geomorphological processes. Moreover, the capability of the three methods to produce high resolution point clouds was evaluated. The obtained topographical changes were very low during the first 6 months (March-October 2016). Measured topographical changes, with TLS and terrestrial SfM, were very low, and these values fall within the range of the acquisition error of the devices used (2-6 cm). The preliminary results indicated the possibilities of a multiscale approach using new technologies to study geomorphological and erosion processes, although long-term studies will be necessary to obtain erosion rates in this semiarid badland area. Acknowledgement This research was supported by ESPAS and eTERA 3D projects (CGL2015- 65569-R and CGL2014-54822-R, funded by the MINECO-FEDER). Estela Nadal-Romero is the recipient of a Ramón y Cajal postdoctoral contract (Spanish Ministry of Economy and Competitiveness).

Stanford automatic photogrammetry research

NASA Technical Reports Server (NTRS)

Quam, L. H.; Hannah, M. J.

1974-01-01

A feasibility study on the problem of computer automated aerial/orbital photogrammetry is documented. The techniques investigated were based on correlation matching of small areas in digitized pairs of stereo images taken from high altitude or planetary orbit, with the objective of deriving a 3-dimensional model for the surface of a planet.

High-accuracy 3-D modeling of cultural heritage: the digitizing of Donatello's "Maddalena".

PubMed

Guidi, Gabriele; Beraldin, J Angelo; Atzeni, Carlo

2004-03-01

Three-dimensional digital modeling of Heritage works of art through optical scanners, has been demonstrated in recent years with results of exceptional interest. However, the routine application of three-dimensional (3-D) modeling to Heritage conservation still requires the systematic investigation of a number of technical problems. In this paper, the acquisition process of the 3-D digital model of the Maddalena by Donatello, a wooden statue representing one of the major masterpieces of the Italian Renaissance which was swept away by the Florence flood of 1966 and successively restored, is described. The paper reports all the steps of the acquisition procedure, from the project planning to the solution of the various problems due to range camera calibration and to material non optically cooperative. Since the scientific focus is centered on the 3-D model overall dimensional accuracy, a methodology for its quality control is described. Such control has demonstrated how, in some situations, the ICP-based alignment can lead to incorrect results. To circumvent this difficulty we propose an alignment technique based on the fusion of ICP with close-range digital photogrammetry and a non-invasive procedure in order to generate a final accurate model. In the end detailed results are presented, demonstrating the improvement of the final model, and how the proposed sensor fusion ensure a pre-specified level of accuracy.

Structure from Motion (SfM) photogrammetry applied to historical imagery: plug & play?

NASA Astrophysics Data System (ADS)

Bakker, Maarten; Lane, Stuart N.

2017-04-01

The development of Structure from Motion (SfM) photogrammetry has led to a vast increase and expansion of geomorphological applications. Highly detailed Digital Elevation Models (DEMs) can be efficiently generated from a variety of platforms that cover a large range of spatial scales. For the application of DEMs in geomorphic change analysis, precision and spatial resolution are not of sole importance, but also their accuracy, temporal resolution and temporal coverage. The use of archival imagery may substantially lengthen temporal coverage, allowing quantification of annual to decadal scale landform change. Whilst archival photogrammetry is not new, a question arises as to how applicable SfM methods are as a more cost-effective and straightforward alternative to the conventional approach. Here, we studied a relatively extreme case where we applied SfM techniques to archival aerial imagery, to investigate the decadal evolution of a low relief braided river. The Borgne is an Alpine river in south-west Switzerland which is strongly affected by flow abstraction for hydropower, allowing the fairly straightforward application of photogrammetry on the near-dry river bed. For 8 sets of scanned historical aerial images in the period 1959-2005 we performed Ground Control Point (GCP) assisted bundle adjustment using both classical archival digital photogrammetry (used as a reference dataset) and SfM based photogrammetry. For the SfM method, no further data were used to constrain camera or exterior orientation parameters a priori, but instead we used these for a posteriori verification. The resulting densified point clouds were registered onto a reference surface based on stable areas, allowing the correction for any systematic error in DEMs that may arise from (random) error in the bundle adjustment. The obtained results show that the quality of the SfM based bundle adjustment is similar to that of the classical photogrammetric approach. Next to image scale, the quality is strongly driven by ability of computer vision techniques to extract tie-points, which is controlled by image texture (quantified here using entropy) and image overlap (redundancy). Depending on the used image set, these characteristics may therefore be effectively exploited or pose a limitation for application. The quality of the results aside, we found that the recovered bundle adjustment parameters were not necessarily correct and that there was the possibility for a trade-off, between estimated focal length and camera flying height for example, such that the right results were obtained if not for the right reasons. This highlights the need to assess camera and exterior orientation parameters, and to address systematic errors that may evolve from this. For the latter, we found that point cloud registration is crucial, particularly in a low relief environment such as a braided river, for accurate change quantification and geomorphic interpretation. We conclude that, given a suitable set of images and considering principles of classical photogrammetric analysis, SfM methods can be effectively applied for archival imagery analysis, but that this is by no means a plug and play methodology.

Unmanned aerial systems for photogrammetry and remote sensing: A review

NASA Astrophysics Data System (ADS)

Colomina, I.; Molina, P.

2014-06-01

We discuss the evolution and state-of-the-art of the use of Unmanned Aerial Systems (UAS) in the field of Photogrammetry and Remote Sensing (PaRS). UAS, Remotely-Piloted Aerial Systems, Unmanned Aerial Vehicles or simply, drones are a hot topic comprising a diverse array of aspects including technology, privacy rights, safety and regulations, and even war and peace. Modern photogrammetry and remote sensing identified the potential of UAS-sourced imagery more than thirty years ago. In the last five years, these two sister disciplines have developed technology and methods that challenge the current aeronautical regulatory framework and their own traditional acquisition and processing methods. Navety and ingenuity have combined off-the-shelf, low-cost equipment with sophisticated computer vision, robotics and geomatic engineering. The results are cm-level resolution and accuracy products that can be generated even with cameras costing a few-hundred euros. In this review article, following a brief historic background and regulatory status analysis, we review the recent unmanned aircraft, sensing, navigation, orientation and general data processing developments for UAS photogrammetry and remote sensing with emphasis on the nano-micro-mini UAS segment.

A morphologic characterisation of the 1963 Vajont Slide, Italy, using long-range terrestrial photogrammetry

NASA Astrophysics Data System (ADS)

Wolter, Andrea; Stead, Doug; Clague, John J.

2014-02-01

The 1963 Vajont Slide in northeast Italy is an important engineering and geological event. Although the landslide has been extensively studied, new insights can be derived by applying modern techniques such as remote sensing and numerical modelling. This paper presents the first digital terrestrial photogrammetric analyses of the failure scar, landslide deposits, and the area surrounding the failure, with a focus on the scar. We processed photogrammetric models to produce discontinuity stereonets, residual maps and profiles, and slope and aspect maps, all of which provide information on the failure scar morphology. Our analyses enabled the creation of a preliminary semi-quantitative morphologic classification of the Vajont failure scar based on the large-scale tectonic folds and step-paths that define it. The analyses and morphologic classification have implications for the kinematics, dynamics, and mechanism of the slide. Metre- and decametre-scale features affected the initiation, direction, and displacement rate of sliding. The most complexly folded and stepped areas occur close to the intersection of orthogonal synclinal features related to the Dinaric and Neoalpine deformation events. Our analyses also highlight, for the first time, the evolution of the Vajont failure scar from 1963 to the present.

The Main Portal of the Cathedral of Monreale: First Geometric Analysis and Interpretive Assessment of Architectural Features

NASA Astrophysics Data System (ADS)

Lo Brutto, M.; Dardanelli, G.; Ebolese, D.; Milazzo, G.; Pipitone, C.; Sciortino, R.

2017-05-01

Nowadays, 3D documentation of architectural assets is becoming a demanding task for the valorisation of Cultural Heritage especially after a restoration project. The 3D documentation can be used for detailed analysis of specific elements, for monitoring the state of conservation and for valorisation actions. The paper describes the results of the 3D close-range photogrammetry survey of the main portal of the Cathedral of Monreale (Palermo, Italy). The Cathedral is one the most important monumental complexes in Sicily that, for its high historical and artistic importance has been inscribed on UNESCO's World Heritage List since 2015. The main portal of the Cathedral has been recently restored. The restoration work has given the opportunity to evidence small details of the sculptural decorations and to carry out new interpretative analysis of the bas-reliefs. The main purpose of the work is to obtain a detailed 3D model and a high-resolution ortophoto of the entire portal and of some architectural details. The study was used to evaluate the most appropriate technical solutions for the 3D survey and to define the most suitable parameters for image acquisition and data processing.

Classification by Using Multispectral Point Cloud Data

NASA Astrophysics Data System (ADS)

Liao, C. T.; Huang, H. H.

2012-07-01

Remote sensing images are generally recorded in two-dimensional format containing multispectral information. Also, the semantic information is clearly visualized, which ground features can be better recognized and classified via supervised or unsupervised classification methods easily. Nevertheless, the shortcomings of multispectral images are highly depending on light conditions, and classification results lack of three-dimensional semantic information. On the other hand, LiDAR has become a main technology for acquiring high accuracy point cloud data. The advantages of LiDAR are high data acquisition rate, independent of light conditions and can directly produce three-dimensional coordinates. However, comparing with multispectral images, the disadvantage is multispectral information shortage, which remains a challenge in ground feature classification through massive point cloud data. Consequently, by combining the advantages of both LiDAR and multispectral images, point cloud data with three-dimensional coordinates and multispectral information can produce a integrate solution for point cloud classification. Therefore, this research acquires visible light and near infrared images, via close range photogrammetry, by matching images automatically through free online service for multispectral point cloud generation. Then, one can use three-dimensional affine coordinate transformation to compare the data increment. At last, the given threshold of height and color information is set as threshold in classification.

Rapid mapping of landslide disaster using UAV- photogrammetry

NASA Astrophysics Data System (ADS)

Cahyono, A. B.; Zayd, R. A.

2018-03-01

Unmanned Aerial Vehicle (UAV) systems offered many advantages in several mapping applications such as slope mapping, geohazard studies, etc. This study utilizes UAV system for landslide disaster occurred in Jombang Regency, East Java. This study concentrates on type of rotor-wing UAV, that is because rotor wing units are stable and able to capture images easily. Aerial photograph were acquired in the form of strips which followed the procedure of acquiring aerial photograph where taken 60 photos. Secondary data of ground control points using GPS Geodetic and check points established using Total Station technique was used. The digital camera was calibrated using close range photogrammetric software and the recovered camera calibration parameters were then used in the processing of digital images. All the aerial photographs were processed using digital photogrammetric software and the output in the form of orthophoto was produced. The final result shows a 1: 1500 scale orthophoto map from the data processing with SfM algorithm with GSD accuracy of 3.45 cm. And the calculated volume of contour line delineation of 10527.03 m3. The result is significantly different from the result of terrestrial methode equal to 964.67 m3 or 8.4% of the difference of both.

Soft tissue response in orthognathic surgery patients treated by bimaxillary osteotomy: cephalometry compared with 2-D photogrammetry.

PubMed

Rustemeyer, Jan; Martin, Alice

2013-03-01

Since improvement of facial aesthetics after orthognathic surgery moves increasingly into the focus of patients, prediction of soft tissue response to hard tissue movement becomes essential for planning. The aim of this study was to assess the facial soft tissue response in skeletal class II and III patients undergoing orthognathic surgery and to compare the potentials of cephalometry and two-dimensional (2-D) photogrammetry for predicting soft tissue changes. Twenty-eight patients with class II relationship and 33 with class III underwent bimaxillary surgery. All subjects had available both a traced lateral cephalogram and a traced lateral photogram taken pre- and postsurgery in natural head position (median follow-up, 9.4 ± 0.6 months). Facial convexity and lower lip length were highly correlated with hard tissue movements cephalometrically in class III patients and 2-D photogrammetrically in both classes. In comparison, cephalometric correlations for class II patients were weak. Correlations of hard and soft tissue movements between pre- and postoperative corresponding landmarks in horizontal and vertical planes were significant for cephalometry and 2-D photogrammetry. No significant difference was found between cephalometry and 2-D photogrammetry with respect to soft to hard tissue movement ratios. This study revealed that cephalometry is still a feasible standard for evaluating and predicting outcomes in routine orthognathic surgery cases. Accuracy could be enhanced with 2-D photogrammetry, especially in class II patients.

3D surface and body documentation in forensic medicine: 3-D/CAD Photogrammetry merged with 3D radiological scanning.

PubMed

Thali, Michael J; Braun, Marcel; Wirth, Joachim; Vock, Peter; Dirnhofer, Richard

2003-11-01

A main goal of forensic medicine is to document and to translate medical findings to a language and/or visualization that is readable and understandable for judicial persons and for medical laymen. Therefore, in addition to classical methods, scientific cutting-edge technologies can and should be used. Through the use of the Forensic, 3-D/CAD-supported Photogrammetric method the documentation of so-called "morphologic fingerprints" has been realized. Forensic, 3-D/CAD-supported Photogrammetry creates morphologic data models of the injury and of the suspected injury-causing instrument allowing the evaluation of a match between the injury and the instrument. In addition to the photogrammetric body surface registration, the radiological documentation provided by a volume scan (i.e., spiral, multi-detector CT, or MRI) registers the sub-surface injury, which is not visible to Photogrammetry. The new, combined method of merging Photogrammetry and Radiology data sets creates the potential to perform many kinds of reconstructions and postprocessing of (patterned) injuries in the realm of forensic medical case work. Using this merging method of colored photogrammetric surface and gray-scale radiological internal documentation, a great step towards a new kind of reality-based, high-tech wound documentation and visualization in forensic medicine is made. The combination of the methods of 3D/CAD Photogrammetry and Radiology has the advantage of being observer-independent, non-subjective, non-invasive, digitally storable over years or decades and even transferable over the web for second opinion.

Morphological and structural changes at the Merapi lava dome monitored using Unmanned Aerial Vehicles (UAVs)

NASA Astrophysics Data System (ADS)

Darmawan, H.; Walter, T. R.; Brotopuspito, K. S.; Subandriyo, S.; Nandaka, M. A.

2017-12-01

Six gas-driven explosions between 2012 and 2014 had changed the morphology and structures of the Merapi lava dome. The explosions mostly occurred during rainfall season and caused NW-SE elongated open fissures that dissected the lava dome. In this study, we conducted UAVs photogrammetry before and after the explosions to investigate the morphological and structural changes and to assess the quality of the UAV photogrammetry. The first UAV photogrammetry was conducted on 26 April 2012. After the explosions, we conducted Terrestrial Laser Scanning (TLS) survey on 18 September 2014 and repeated UAV photogrammetry on 6 October 2015. We applied Structure from Motion (SfM) algorithm to reconstruct 3D SfM point clouds and photomosaics of the 2012 and 2015 UAVs images. Topography changes has been analyzed by calculating height difference between the 2012 and 2015 SfM point clouds, while structural changes has been investigated by visual comparison between the 2012 and 2015 photo mosaics. Moreover, a quality assessment of the results of UAV photogrammetry has been done by comparing the 3D SfM point clouds to TLS dataset. Result shows that the 2012 and 2015 SfM point clouds have 0.19 and 0.57 m difference compared to the TLS point cloud. Furthermore, topography, and structural changes reveal that the 2012-14 explosions were controlled by pre-existing structures. The volume of the 2012-14 explosions is 26.400 ± 1320 m3 DRE. In addition, we find a structurally delineated unstable block at the southern front of the dome which potentially collapses in the future. We concluded that the 2012-14 explosions occurred due to interaction between magma intrusion and rain water and were facilitated by pre-existing structures. The unstable block potentially leads to a rock avalanche hazard. Furthermore, our drone photogrammetry results show very promising and therefore we recommend to use drone for topography mapping in lava dome building volcanoes.

Precision of three-dimensional stereo-photogrammetry (3dMD™) in anthropometry of the auricle and its application in microtia reconstruction.

PubMed

Chen, Zung-Chung; Albdour, Mohammad Nayef; Lizardo, Jesus Ablaza; Chen, Ying-An; Chen, Philip Kuo-Ting

2015-05-01

The advent of three-dimensional stereo-photogrammetry in recent years has vastly helped the craniomaxillofacial field improve in terms of preoperative and intraoperative decision making. With regard to the auricle though, there is paucity of research as to the application of this promising technology. A total of 20 normal adult ears were included in this study. Thirteen anthropometric measurements were taken, twice by two plastic surgeons using direct measurement (DM) and through images captured via 3dMD™. The purpose was to compare the reliability of measurements involving the two instruments. The overall mean absolute differences (MADs) of all ear anthropometries of DM and 3dMD™ were 0.52 mm (range: 0.28-0.72 mm) and 0.27 mm (range: 0.15-0.53 mm), respectively, and the grand mean relative error magnitudes (REMs) were 2.85% (range: 1.01-5.99%) and 1.57% (range: 0.48-3.62%), respectively, across observers. Thus, the precision of all ear anthropometries across observers was high in both methods, but the precision of 3dMD was better than DM irrespective of observers. In addition, the MADs were less than a millimeter across all measurements. The application of three-dimensional technology in microtia surgery for both template production and soft tissue analysis leads to improved planning and satisfactory results with fewer complications. We believe that with further refinement and enhancement, the use of this innovation will pave the way for prefabricated, individualized autologous or biocompatible alloplastic implantable frameworks based on an accurate mirror image of each patient's normal ear in unilateral cases and in bilateral cases, appropriately sized. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Television, Photogrammetry, Photometry, and Radiometry Adaptable to Space Reconnaissance

DTIC Science & Technology

1963-11-01

exposure in the range 1/t-2 minutes. The rota- v. 70, pp. 308-310, 1959 tion is nonuniform and this is achieved by using an ac driving (Also available...combining the correlogram of a WITH NONUNIFORM GRANULARITY SPECTRA negative *.s affected by the printing procedure with the cor- Stultz, K. F., Zweig, H...potentials and velocities, the required bandwidth could beThe system chosen employs the optimal nonuniform reduced to one-fourth of that used at present

Brief communication: 3-D reconstruction of a collapsed rock pillar from Web-retrieved images and terrestrial lidar data - the 2005 event of the west face of the Drus (Mont Blanc massif)

NASA Astrophysics Data System (ADS)

Guerin, Antoine; Abellán, Antonio; Matasci, Battista; Jaboyedoff, Michel; Derron, Marc-Henri; Ravanel, Ludovic

2017-07-01

In June 2005, a series of major rockfall events completely wiped out the Bonatti Pillar located in the legendary Drus west face (Mont Blanc massif, France). Terrestrial lidar scans of the west face were acquired after this event, but no pre-event point cloud is available. Thus, in order to reconstruct the volume and the shape of the collapsed blocks, a 3-D model has been built using photogrammetry (structure-from-motion (SfM) algorithms) based on 30 pictures collected on the Web. All these pictures were taken between September 2003 and May 2005. We then reconstructed the shape and volume of the fallen compartment by comparing the SfM model with terrestrial lidar data acquired in October 2005 and November 2011. The volume is calculated to 292 680 m3 (±5.6 %). This result is close to the value previously assessed by Ravanel and Deline (2008) for this same rock avalanche (265 000 ± 10 000 m3). The difference between these two estimations can be explained by the rounded shape of the volume determined by photogrammetry, which may lead to a volume overestimation. However it is not excluded that the volume calculated by Ravanel and Deline (2008) is slightly underestimated, the thickness of the blocks having been assessed manually from historical photographs.

Stereo x-ray photogrammetry applied for prevention of sigmoid-colon damage caused by radiation from intrauterine sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuipers, T.

1982-06-01

Radiation therapy of cervix carcinoma is applied in this Institute by means of modified Stockholm method in combination with external beam irradiation. In 1968, parametrial portals were replaced by large planeparallel opposed fields extending cranially to LIII/LIV with central shielding in order to avoid overdosage in the area of intracavitary treatment. This resulted in a marked increased incidence of serere sigmoid-colon radiation lesions from 0.25% to 4%; predominantly in Stage I and II patients. Therefore two measures have been introduced: beginning in 1972 measures were taken to prevent the cranial displacement of the uterus during intracavitary treatment in order tomore » avoid shortening the distance between the radioactive sources and the sigmoid-colon; from 1973 stereo X ray photogrammetry (SRM) was applied for dose determinations at points of the sigmoid-colon, which were seen to be located close to the applicator. When SRM data indicated that a high dose at the sigmoid-colon might occur, treatment modifications enabled prevention of radiation damage. Change of position of the applicator was the first to be considered. In the last seven years no surgical intervention had to be performed because of a sigmoid-colon lesion resulting from an unexpected high radiation dose delivered by intrauterine sources. The local recurrence rate was not increased following treatment modifications for prevention of sigmoid-colon radiation damage.« less

Photogrammetry System and Method for Determining Relative Motion Between Two Bodies

NASA Technical Reports Server (NTRS)

Miller, Samuel A. (Inventor); Severance, Kurt (Inventor)

2014-01-01

A photogrammetry system and method provide for determining the relative position between two objects. The system utilizes one or more imaging devices, such as high speed cameras, that are mounted on a first body, and three or more photogrammetry targets of a known location on a second body. The system and method can be utilized with cameras having fish-eye, hyperbolic, omnidirectional, or other lenses. The system and method do not require overlapping fields-of-view if two or more cameras are utilized. The system and method derive relative orientation by equally weighting information from an arbitrary number of heterogeneous cameras, all with non-overlapping fields-of-view. Furthermore, the system can make the measurements with arbitrary wide-angle lenses on the cameras.

Photogrammetry and Videogrammetry Methods Development for Solar Sail Structures. Masters Thesis awarded by George Washington Univ.

NASA Technical Reports Server (NTRS)

Pappa, Richard S. (Technical Monitor); Black, Jonathan T.

2003-01-01

This report discusses the development and application of metrology methods called photogrammetry and videogrammetry that make accurate measurements from photographs. These methods have been adapted for the static and dynamic characterization of gossamer structures, as four specific solar sail applications demonstrate. The applications prove that high-resolution, full-field, non-contact static measurements of solar sails using dot projection photogrammetry are possible as well as full-field, non-contact, dynamic characterization using dot projection videogrammetry. The accuracy of the measurement of the resonant frequencies and operating deflection shapes that were extracted surpassed expectations. While other non-contact measurement methods exist, they are not full-field and require significantly more time to take data.

Photogrammetry of a Hypersonic Inflatable Aerodynamic Decelerator

NASA Technical Reports Server (NTRS)

Kushner, Laura Kathryn; Littell, Justin D.; Cassell, Alan M.

2013-01-01

In 2012, two large-scale models of a Hypersonic Inflatable Aerodynamic decelerator were tested in the National Full-Scale Aerodynamic Complex at NASA Ames Research Center. One of the objectives of this test was to measure model deflections under aerodynamic loading that approximated expected flight conditions. The measurements were acquired using stereo photogrammetry. Four pairs of stereo cameras were mounted inside the NFAC test section, each imaging a particular section of the HIAD. The views were then stitched together post-test to create a surface deformation profile. The data from the photogram- metry system will largely be used for comparisons to and refinement of Fluid Structure Interaction models. This paper describes how a commercial photogrammetry system was adapted to make the measurements and presents some preliminary results.

Advanced Photogrammetry to Assess Lichen Colonization in the Hyper-Arid Namib Desert.

PubMed

Hinchliffe, Graham; Bollard-Breen, Barbara; Cowan, Don A; Doshi, Ashray; Gillman, Len N; Maggs-Kolling, Gillian; de Los Rios, Asuncion; Pointing, Stephen B

2017-01-01

The hyper-arid central region of the Namib Desert is characterized by quartz desert pavement terrain that is devoid of vascular plant covers. In this extreme habitat the only discernible surface covers are epilithic lichens that colonize exposed surfaces of quartz rocks. These lichens are highly susceptible to disturbance and so field surveys have been limited due to concerns about disturbing this unusual desert feature. Here we present findings that illustrate how non-destructive surveys based upon advanced photogrammetry techniques can yield meaningful and novel scientific data on these lichens. We combined 'structure from motion analysis,' computer vision and GIS to create 3-dimensional point clouds from two-dimensional imagery. The data were robust in its application to estimating absolute lichen cover. An orange Stellarangia spp. assemblage had coverage of 22.8% of available substrate, whilst for a black Xanthoparmelia spp. assemblage coverage was markedly lower at 0.6% of available substrate. Hyperspectral signatures for both lichens were distinct in the near-infra red range indicating that Xanthoparmelia spp. was likely under relatively more moisture stress than Stellarangia spp. at the time of sampling, and we postulate that albedo effects may have contributed to this in the black lichen. Further transformation of the data revealed a colonization preference for west-facing quartz surfaces and this coincides with prevailing winds for marine fog that is the major source of moisture in this system. Furthermore, a three-dimensional 'fly through' of the lichen habitat was created to illustrate how the application of computer vision in microbiology has further potential as a research and education tool. We discuss how advanced photogrammetry could be applied in astrobiology using autonomous rovers to add quantitative ecological data for visible surface colonization on the surface of Mars.

Advanced Photogrammetry to Assess Lichen Colonization in the Hyper-Arid Namib Desert

PubMed Central

Hinchliffe, Graham; Bollard-Breen, Barbara; Cowan, Don A.; Doshi, Ashray; Gillman, Len N.; Maggs-Kolling, Gillian; de Los Rios, Asuncion; Pointing, Stephen B.

2017-01-01

The hyper-arid central region of the Namib Desert is characterized by quartz desert pavement terrain that is devoid of vascular plant covers. In this extreme habitat the only discernible surface covers are epilithic lichens that colonize exposed surfaces of quartz rocks. These lichens are highly susceptible to disturbance and so field surveys have been limited due to concerns about disturbing this unusual desert feature. Here we present findings that illustrate how non-destructive surveys based upon advanced photogrammetry techniques can yield meaningful and novel scientific data on these lichens. We combined ‘structure from motion analysis,’ computer vision and GIS to create 3-dimensional point clouds from two-dimensional imagery. The data were robust in its application to estimating absolute lichen cover. An orange Stellarangia spp. assemblage had coverage of 22.8% of available substrate, whilst for a black Xanthoparmelia spp. assemblage coverage was markedly lower at 0.6% of available substrate. Hyperspectral signatures for both lichens were distinct in the near-infra red range indicating that Xanthoparmelia spp. was likely under relatively more moisture stress than Stellarangia spp. at the time of sampling, and we postulate that albedo effects may have contributed to this in the black lichen. Further transformation of the data revealed a colonization preference for west-facing quartz surfaces and this coincides with prevailing winds for marine fog that is the major source of moisture in this system. Furthermore, a three-dimensional ‘fly through’ of the lichen habitat was created to illustrate how the application of computer vision in microbiology has further potential as a research and education tool. We discuss how advanced photogrammetry could be applied in astrobiology using autonomous rovers to add quantitative ecological data for visible surface colonization on the surface of Mars. PMID:29312153

Impression of multiple implants using photogrammetry: Description of technique and case presentation

PubMed Central

Peñarrocha-Oltra, David; Agustín-Panadero, Rubén; Bagán, Leticia; Giménez, Beatriz

2014-01-01

Aim: To describe a technique for registering the positions of multiple dental implants using a system based on photogrammetry. A case is presented in which a prosthetic treatment was performed using this technique. Study Design: Three Euroteknika® dental implants were placed to rehabilitate a 55-year-old male patient with right posterior maxillary edentulism. Three months later, the positions of the implants were registered using a photogrammetry-based stereo-camera (PICcamera®). After processing patient and implant data, special abutments (PICabutment®) were screwed onto each implant. The PICcamera® was then used to capture images of the implant positions, automatically taking 150 images in less than 60 seconds. From this information a file was obtained describing the relative positions – angles and distances – of each implant in vector form. Information regarding the soft tissues was obtained from an alginate impression that was cast in plaster and scanned. A Cr-Co structure was obtained using CAD/CAM, and its passive fit was verified in the patient’s mouth using the Sheffield test and the screw resistance test. Results and Conclusions: Twelve months after loading, peri-implant tissues were healthy and no marginal bone loss was observed. The clinical application of this new system using photogrammetry to record the position of multiple dental implants facilitated the rehabilitation of a patient with posterior maxillary edentulism by means of a prosthesis with optimal fit. The prosthetic process was accurate, fast, simple to apply and comfortable for the patient. Key words:Dental implants, photogrammetry, dental impression technique, CAD/CAM. PMID:24608216

The Photogrammetry Cube

NASA Technical Reports Server (NTRS)

2008-01-01

We can determine distances between objects and points of interest in 3-D space to a useful degree of accuracy from a set of camera images by using multiple camera views and reference targets in the camera s field of view (FOV). The core of the software processing is based on the previously developed foreign-object debris vision trajectory software (see KSC Research and Technology 2004 Annual Report, pp. 2 5). The current version of this photogrammetry software includes the ability to calculate distances between any specified point pairs, the ability to process any number of reference targets and any number of camera images, user-friendly editing features, including zoom in/out, translate, and load/unload, routines to help mark reference points with a Find function, while comparing them with the reference point database file, and a comprehensive output report in HTML format. In this system, scene reference targets are replaced by a photogrammetry cube whose exterior surface contains multiple predetermined precision 2-D targets. Precise measurement of the cube s 2-D targets during the fabrication phase eliminates the need for measuring 3-D coordinates of reference target positions in the camera's FOV, using for example a survey theodolite or a Faroarm. Placing the 2-D targets on the cube s surface required the development of precise machining methods. In response, 2-D targets were embedded into the surface of the cube and then painted black for high contrast. A 12-inch collapsible cube was developed for room-size scenes. A 3-inch, solid, stainless-steel photogrammetry cube was also fabricated for photogrammetry analysis of small objects.

Detection and Evaluation of Skin Disorders by One of Photogrammetric Image Analysis Methods

NASA Astrophysics Data System (ADS)

Güçin, M.; Patias, P.; Altan, M. O.

2012-08-01

Abnormalities on skin may vary from simple acne to painful wounds which affect a person's life quality. Detection of these kinds of disorders in early stages, followed by the evaluation of abnormalities is of high importance. At this stage, photogrammetry offers a non-contact solution to this concern by providing geometric highly accurate data. Photogrammetry, which has been used for firstly topographic purposes, in virtue of terrestrial photogrammetry became useful technique in non-topographic applications also (Wolf et al., 2000). Moreover the extension of usage of photogrammetry, in parallel with the development in technology, analogue photographs are replaced with digital images and besides digital image processing techniques, it provides modification of digital images by using filters, registration processes etc. Besides, photogrammetry (using same coordinate system by registration of images) can serve as a tool for the comparison of temporal imaging data. The aim of this study is to examine several digital image processing techniques, in particular the digital filters, which might be useful to determine skin disorders. In our study we examine affordable to purchase, user friendly software which needs neither expertise nor pre-training. Since it is a pre-work for subsequent and deeper studies, Adobe Photoshop 7.0 is used as a present software. In addition to that Adobe Photoshop released a DesAcc plug-ins with CS3 version and provides full compatibility with DICOM (Digital Imaging and Communications in Medicine) and PACS (Picture Archiving and Communications System) that enables doctors to store all medical data together with relevant images and share if necessary.

Clinical experience with a 3D surface patient setup system for alignment of partial-breast irradiation patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bert, Christoph; Metheany, Katherine G.; Doppke, Karen P.

2006-03-15

Purpose: To assess the utility of surface imaging on patient setup for accelerated partial-breast irradiation (APBI). Methods and Material: A photogrammetry system was used in parallel to APBI setup by laser and portal imaging. Surface data were acquired after laser and port-film setup for 9 patients. Surfaces were analyzed in comparison to a reference surface from the first treatment session by use of rigid transformations. The surface model after laser setup was used in a simulated photogrammetry setup procedure. In addition, breathing data were acquired by surface acquisition at a frame rate of 7 Hz. Results: Mean 3D displacement wasmore » 7.3 mm (SD, 4.4 mm) and 7.6 mm (SD, 4.2 mm) for laser and port film, respectively. Simulated setup with the photogrammetry system yielded mean displacement of 1 mm (SD, 1.2 mm). Distance analysis resulted in mean distances of 3.7 mm (SD, 4.9 mm), 4.3 mm (SD, 5.6 mm), and 1.6 mm (SD, 2.4 mm) for laser, port film, and photogrammetry, respectively. Breathing motion at isocenter was smaller than 3.7 mm, with a mean of 1.9 mm (SD, 1.1 mm). Conclusions: Surface imaging for PBI setup appears promising. Alignment of the 3D breast surface achieved by stereo-photogrammetry shows greater breast topology congruence than when patients are set up by laser or portal imaging. A correlation of breast surface and CTV must be quantitatively established.« less

Caliper Method Versus Digital Photogrammetry for Assessing Arch Height Index in Pregnant Women.

PubMed

Harrison, Kathryn D; McCrory, Jean L

2016-11-01

Foot anthropometry may be altered during pregnancy. Pregnant women often report lower-extremity pain that may be related to these alterations. The Arch Height Index Measurement System is a common method of foot arch assessment; however, the required calipers are costly and are not widely available. Thus, we compared the reliability of a digital photogrammetry method of arch height index (AHI) assessment with that of the Arch Height Index Measurement System. Ten pregnant women (mean ± SD: age, 29 ± 4 years; height, 166.9 ± 6.8 cm; weight, 63.3 ± 8.8 kg) in their second trimester were recruited to participate, along with a control group of 10 nulliparous weight-matched women (mean ± SD: age, 22 ± 2 years; height, 164.6 ± 4.8 cm; weight, 61.5 ± 8.1 kg). During the second and third trimesters, and once postpartum, AHI was assessed using calipers and using digital photogrammetry. Mixed model absolute agreement type intraclass correlation coefficient (ICC) was used to determine correlation between the two methods for sitting and standing AHI. The ICC results for sitting AHI only (0.819-0.968) were reasonable for clinical measures; ICC values for standing AHI (0.674-0.789) did not reach values deemed reasonable for clinical use. Caliper and digital photogrammetry methods of AHI assessment are correlated in pregnant women; however, for standing AHI, the correlation is not sufficient for clinical use. Photogrammetry may still be appropriate for clinical use, as long as values from this method are not substituted directly for results obtained from calipers.

Fine-resolution repeat topographic surveying of dryland landscapes using UAS-based structure-from-motion photogrammetry: Assessing accuracy and precision against traditional ground-based erosion measurements

USDA-ARS?s Scientific Manuscript database

Structure-from-motion (SfM) photogrammetry from unmanned aircraft system (UAS) imagery is an emerging tool for repeat topographic surveying of dryland erosion. These methods are particularly appealing due to the ability to cover large landscapes compared to field methods and at reduced costs and hig...

A smartphone photogrammetry method for digitizing prosthetic socket interiors.

PubMed

Hernandez, Amaia; Lemaire, Edward

2017-04-01

Prosthetic CAD/CAM systems require accurate 3D limb models; however, difficulties arise when working from the person's socket since current 3D scanners have difficulties scanning socket interiors. While dedicated scanners exist, they are expensive and the cost may be prohibitive for a limited number of scans per year. A low-cost and accessible photogrammetry method for socket interior digitization is proposed, using a smartphone camera and cloud-based photogrammetry services. 15 two-dimensional images of the socket's interior are captured using a smartphone camera. A 3D model is generated using cloud-based software. Linear measurements were comparing between sockets and the related 3D models. 3D reconstruction accuracy averaged 2.6 ± 2.0 mm and 0.086 ± 0.078 L, which was less accurate than models obtained by high quality 3D scanners. However, this method would provide a viable 3D digital socket reproduction that is accessible and low-cost, after processing in prosthetic CAD software. Clinical relevance The described method provides a low-cost and accessible means to digitize a socket interior for use in prosthetic CAD/CAM systems, employing a smartphone camera and cloud-based photogrammetry software.

a Three-Dimensional Simulation and Visualization System for Uav Photogrammetry

NASA Astrophysics Data System (ADS)

Liang, Y.; Qu, Y.; Cui, T.

2017-08-01

Nowadays UAVs has been widely used for large-scale surveying and mapping. Compared with manned aircraft, UAVs are more cost-effective and responsive. However, UAVs are usually more sensitive to wind condition, which greatly influences their positions and orientations. The flight height of a UAV is relative low, and the relief of the terrain may result in serious occlusions. Moreover, the observations acquired by the Position and Orientation System (POS) are usually less accurate than those acquired in manned aerial photogrammetry. All of these factors bring in uncertainties to UAV photogrammetry. To investigate these uncertainties, a three-dimensional simulation and visualization system has been developed. The system is demonstrated with flight plan evaluation, image matching, POS-supported direct georeferencing, and ortho-mosaicing. Experimental results show that the presented system is effective for flight plan evaluation. The generated image pairs are accurate and false matches can be effectively filtered. The presented system dynamically visualizes the results of direct georeferencing in three-dimensions, which is informative and effective for real-time target tracking and positioning. The dynamically generated orthomosaic can be used in emergency applications. The presented system has also been used for teaching theories and applications of UAV photogrammetry.

Photogrammetry in the line: recent developments in industrial photogrammetry

NASA Astrophysics Data System (ADS)

Boesemann, Werner

2003-05-01

In recent years industrial photogrammetry has emerged from a highly specialized niche technology to a well established tool in industrial coordinate measurement applications with numerous installations in a significantly growing market of flexible and portable optical measurement systems. This is due to the development of powerful, but affordable video and computer technology. The increasing industrial requirements for accuracy, speed, robustness and ease of use of these systems together with a demand for the highest possible degree of automation have forced universities and system manufacturers to develop hard- and software solutions to meet these requirements. The presentation will show the latest trends in hardware development, especially new generation digital and/or intelligent cameras, aspects of image engineering like use of controlled illumination or projection technologies,and algorithmic and software aspects like automation strategies or new camera models. The basic qualities of digital photogrammetry-like portability and flexibility on one hand and fully automated quality control on the other -- sometimes lead to certain conflicts in the design of measurement systems for different online, offline or real-time solutions. The presentation will further show, how these tools and methods are combined in different configurations to be able to cover the still growing demands of the industrial end-users.

A single camera photogrammetry system for multi-angle fast localization of EEG electrodes.

PubMed

Qian, Shuo; Sheng, Yang

2011-11-01

Photogrammetry has become an effective method for the determination of electroencephalography (EEG) electrode positions in three dimensions (3D). Capturing multi-angle images of the electrodes on the head is a fundamental objective in the design of photogrammetry system for EEG localization. Methods in previous studies are all based on the use of either a rotating camera or multiple cameras, which are time-consuming or not cost-effective. This study aims to present a novel photogrammetry system that can realize simultaneous acquisition of multi-angle head images in a single camera position. Aligning two planar mirrors with the angle of 51.4°, seven views of the head with 25 electrodes are captured simultaneously by the digital camera placed in front of them. A complete set of algorithms for electrode recognition, matching, and 3D reconstruction is developed. It is found that the elapsed time of the whole localization procedure is about 3 min, and camera calibration computation takes about 1 min, after the measurement of calibration points. The positioning accuracy with the maximum error of 1.19 mm is acceptable. Experimental results demonstrate that the proposed system provides a fast and cost-effective method for the EEG positioning.

Photogrammetry Impression Technique: A Case History Report.

PubMed

Sánchez-Monescillo, Andrés; Sánchez-Turrión, Andrés; Vellon-Domarco, Elena; Salinas-Goodier, Carmen; Prados-Frutos, Juan Carlos

2016-01-01

The aim of this report is to present photogrammetry as a reliable step in the fabrication of a full-arch immediate rehabilitation. A 59-year-old man attended the department seeking dental rehabilitation for the sequelae of severe oral health neglect. The mandibular teeth suffered from advanced periodontal disease and the patient wore a maxillary complete denture. An irreversible hydrocolloid impression of the mandibular arch was made, poured in stone, and digitally scanned to create the first stereolithography (STL) file. All teeth with the exception of two retained as landmarks were extracted, and seven implants were placed under local anesthesia and their positions recorded using photogrammetry. Maxillary and mandibular dental arch alginate impressions were made, poured in laboratory stone, and scanned. A provisional restoration was placed 7 hours after surgery using the STL files to determine the best-fit line. Radiographic and clinical follow-up after 1 year showed a favorable evolution of the implants. No screw loosening or other mechanical or biologic complications were observed. The case history using the described system suggests certain advantages over conventional techniques. More research is needed to assess the possible benefits associated with photogrammetry when making implant-supported restorations.

Stereo Photogrammetry Measurements of the Position and Attitude of a Nozzle-Plume/Shock-Wave Interaction Model in the NASA Ames 9- by 7-Ft Supersonic Wind Tunnel

NASA Technical Reports Server (NTRS)

Schairer, Edward T.; Kushner, Laura K.; Drain, Bethany A.; Heineck, James T.; Durston, Donald A.

2017-01-01

Stereo photogrammetry was used to measure the position and attitude of a slender body of revolution during nozzle-plume/shock-wave interaction tests in the NASA Ames 9- by 7-Ft Supersonic Wind Tunnel. The model support system was designed to allow the model to be placed at many locations in the test section relative to a pressure rail on one sidewall. It included a streamwise traverse as well as a thin blade that offset the model axis from the sting axis. With these features the support system was more flexible than usual resulting in higher-than-usual uncertainty in the position and attitude of the model. Also contributing to this uncertainty were the absence of a balance, so corrections for sting deflections could not be applied, and the wings-vertical orientation of the model, which precluded using a gravity-based accelerometer to measure pitch angle. Therefore, stereo photogrammetry was chosen to provide independent measures of the model position and orientation. This paper describes the photogrammetry system and presents selected results from the test.

Evidence of spring formation and subrosion-induced sinkhole development at Ghor Al-Haditha, Jordan, from repeated close-range photogrammetry

NASA Astrophysics Data System (ADS)

Al-Halbouni, Djamil; Eoghan, P. Holohan; Leila, Saberi; Hussam, Alrshdan; Thomas, Walter; Ali, Sawarieh; Torsten, Dahm

2016-04-01

The widespread development of sinkholes and land subsidence poses a major geological hazard to infrastructure, local population, agriculture and industry in the Dead Sea area. For assessment of the key physical factors in this development, repeated photogrammetric and field surveys at Ghor Al-Haditha in Jordan have been undertaken. Recent results provide evidence for subrosion based on strong periodic water flows, as the basic underlying physical process of such land subsidence phenomena. From combined Helikite- and Quatrocopter-based photogrammetric surveys, high resolution Digital Surface Models from October 2014 and October 2015 are compared. Change detection reveals: (1) active subsidence in a hundred metre-scale depression zone, (2) a highly-dynamic spring and canyon system connected with recent sinkhole collapses and (3) the rapid formation of new sinkholes both in alluvium and mud cover sediments. The formation of new sinkholes has been documented locally by means of aerial and field observations during a storm with strong rainfall. A new artesian spring formed in the former Dead Sea bed (mud-flat) at this event. The alluvial sediment load of the stream, a periodic location change of the spring and a connected uphill sinkhole cluster formation provide strong evidence for subrosion of weak material with subsequent underground void collapse. Additionally a documented lake and its' subsequent drainage forming a new canyon reveals the local penetration of the aquiclude behavior of the mud-flat in the major depression area, which can be explained by an under-saturated groundwater flow at a strong hydrostatic gradient. Furthermore an enlargement of the investigated area in the 2015 survey indicates a continuation of subsidence and sinkhole activity towards the North. It reveals several points of emanation of water streams in the mud-flat beneath the alluvial cover and vegetation as an indicator of relatively fresh groundwater inflow. This repeated photogrammetry and field survey confirms the hypothesis of a large-scale, channelized subterranean water flow in a 3d network of interconnected tubes. This subsurface karstic channel network is hence responsible for sinkhole formation and rapid land subsidence at the Ghor Al-Haditha sinkhole area and perhaps elsewhere around the Dead Sea.

Navigation and Remote Sensing Payloads and Methods of the Sarvant Unmanned Aerial System

NASA Astrophysics Data System (ADS)

Molina, P.; Fortuny, P.; Colomina, I.; Remy, M.; Macedo, K. A. C.; Zúnigo, Y. R. C.; Vaz, E.; Luebeck, D.; Moreira, J.; Blázquez, M.

2013-08-01

In a large number of scenarios and missions, the technical, operational and economical advantages of UAS-based photogrammetry and remote sensing over traditional airborne and satellite platforms are apparent. Airborne Synthetic Aperture Radar (SAR) or combined optical/SAR operation in remote areas might be a case of a typical "dull, dirty, dangerous" mission suitable for unmanned operation - in harsh environments such as for example rain forest areas in Brazil, topographic mapping of small to medium sparsely inhabited remote areas with UAS-based photogrammetry and remote sensing seems to be a reasonable paradigm. An example of such a system is the SARVANT platform, a fixed-wing aerial vehicle with a six-meter wingspan and a maximumtake- of-weight of 140 kilograms, able to carry a fifty-kilogram payload. SARVANT includes a multi-band (X and P) interferometric SAR payload, as the P-band enables the topographic mapping of densely tree-covered areas, providing terrain profile information. Moreover, the combination of X- and P-band measurements can be used to extract biomass estimations. Finally, long-term plan entails to incorporate surveying capabilities also at optical bands and deliver real-time imagery to a control station. This paper focuses on the remote-sensing concept in SARVANT, composed by the aforementioned SAR sensor and envisioning a double optical camera configuration to cover the visible and the near-infrared spectrum. The flexibility on the optical payload election, ranging from professional, medium-format cameras to mass-market, small-format cameras, is discussed as a driver in the SARVANT development. The paper also focuses on the navigation and orientation payloads, including the sensors (IMU and GNSS), the measurement acquisition system and the proposed navigation and orientation methods. The latter includes the Fast AT procedure, which performs close to traditional Integrated Sensor Orientation (ISO) and better than Direct Sensor Orientation (DiSO), and features the advantage of not requiring the massive image processing load for the generation of tie points, although it does require some Ground Control Points (GCPs). This technique is further supported by the availability of a high quality INS/GNSS trajectory, motivated by single-pass and repeat-pass SAR interferometry requirements.

Assessment of engineered surfaces roughness by high-resolution 3D SEM photogrammetry.

PubMed

Gontard, L C; López-Castro, J D; González-Rovira, L; Vázquez-Martínez, J M; Varela-Feria, F M; Marcos, M; Calvino, J J

2017-06-01

We describe a methodology to obtain three-dimensional models of engineered surfaces using scanning electron microscopy and multi-view photogrammetry (3DSEM). For the reconstruction of the 3D models of the surfaces we used freeware available in the cloud. The method was applied to study the surface roughness of metallic samples patterned with parallel grooves by means of laser. The results are compared with measurements obtained using stylus profilometry (PR) and SEM stereo-photogrammetry (SP). The application of 3DSEM is more time demanding than PR or SP, but it provides a more accurate representation of the surfaces. The results obtained with the three techniques are compared by investigating the influence of sampling step on roughness parameters. Copyright © 2017 Elsevier B.V. All rights reserved.

The Practical Application of Uav-Based Photogrammetry Under Economic Aspects

NASA Astrophysics Data System (ADS)

Sauerbier, M.; Siegrist, E.; Eisenbeiss, H.; Demir, N.

2011-09-01

Nowadays, small size UAVs (Unmanned Aerial Vehicles) have reached a level of practical reliability and functionality that enables this technology to enter the geomatics market as an additional platform for spatial data acquisition. Though one could imagine a wide variety of interesting sensors to be mounted on such a device, here we will focus on photogrammetric applications using digital cameras. In praxis, UAV-based photogrammetry will only be accepted if it a) provides the required accuracy and an additional value and b) if it is competitive in terms of economic application compared to other measurement technologies. While a) was already proven by the scientific community and results were published comprehensively during the last decade, b) still has to be verified under real conditions. For this purpose, a test data set representing a realistic scenario provided by ETH Zurich was used to investigate cost effectiveness and to identify weak points in the processing chain that require further development. Our investigations are limited to UAVs carrying digital consumer cameras, for larger UAVs equipped with medium format cameras the situation has to be considered as significantly different. Image data was acquired during flights using a microdrones MD4-1000 quadrocopter equipped with an Olympus PE-1 digital compact camera. From these images, a subset of 5 images was selected for processing in order to register the effort of time required for the whole production chain of photogrammetric products. We see the potential of mini UAV-based photogrammetry mainly in smaller areas, up to a size of ca. 100 hectares. Larger areas can be efficiently covered by small airplanes with few images, reducing processing effort drastically. In case of smaller areas of a few hectares only, it depends more on the products required. UAVs can be an enhancement or alternative to GNSS measurements, terrestrial laser scanning and ground based photogrammetry. We selected the above mentioned test data from a project featuring an area of interest within the practical range for mini UAVs. While flight planning and flight operation are already quite efficient processes, the bottlenecks identified are mainly related to image processing. Although we used specific software for image processing, the identified gaps in the processing chain today are valid for most commercial photogrammetric software systems on the market. An outlook proposing improvements for a practicable workflow applicable in projects in private economy will be given.

Considerations for Achieving Cross-Platform Point Cloud Data Fusion across Different Dryland Ecosystem Structural States

PubMed Central

Swetnam, Tyson L.; Gillan, Jeffrey K.; Sankey, Temuulen T.; McClaran, Mitchel P.; Nichols, Mary H.; Heilman, Philip; McVay, Jason

2018-01-01

Remotely sensing recent growth, herbivory, or disturbance of herbaceous and woody vegetation in dryland ecosystems requires high spatial resolution and multi-temporal depth. Three dimensional (3D) remote sensing technologies like lidar, and techniques like structure from motion (SfM) photogrammetry, each have strengths and weaknesses at detecting vegetation volume and extent, given the instrument's ground sample distance and ease of acquisition. Yet, a combination of platforms and techniques might provide solutions that overcome the weakness of a single platform. To explore the potential for combining platforms, we compared detection bias amongst two 3D remote sensing techniques (lidar and SfM) using three different platforms [ground-based, small unmanned aerial systems (sUAS), and manned aircraft]. We found aerial lidar to be more accurate for characterizing the bare earth (ground) in dense herbaceous vegetation than either terrestrial lidar or aerial SfM photogrammetry. Conversely, the manned aerial lidar did not detect grass and fine woody vegetation while the terrestrial lidar and high resolution near-distance (ground and sUAS) SfM photogrammetry detected these and were accurate. UAS SfM photogrammetry at lower spatial resolution under-estimated maximum heights in grass and shrubs. UAS and handheld SfM photogrammetry in near-distance high resolution collections had similar accuracy to terrestrial lidar for vegetation, but difficulty at measuring bare earth elevation beneath dense herbaceous cover. Combining point cloud data and derivatives (i.e., meshes and rasters) from two or more platforms allowed for more accurate measurement of herbaceous and woody vegetation (height and canopy cover) than any single technique alone. Availability and costs of manned aircraft lidar collection preclude high frequency repeatability but this is less limiting for terrestrial lidar, sUAS and handheld SfM. The post-processing of SfM photogrammetry data became the limiting factor at larger spatial scale and temporal repetition. Despite the utility of sUAS and handheld SfM for monitoring vegetation phenology and structure, their spatial extents are small relative to manned aircraft. PMID:29379511

Considerations for Achieving Cross-Platform Point Cloud Data Fusion across Different Dryland Ecosystem Structural States.

PubMed

Swetnam, Tyson L; Gillan, Jeffrey K; Sankey, Temuulen T; McClaran, Mitchel P; Nichols, Mary H; Heilman, Philip; McVay, Jason

2017-01-01

Remotely sensing recent growth, herbivory, or disturbance of herbaceous and woody vegetation in dryland ecosystems requires high spatial resolution and multi-temporal depth. Three dimensional (3D) remote sensing technologies like lidar, and techniques like structure from motion (SfM) photogrammetry, each have strengths and weaknesses at detecting vegetation volume and extent, given the instrument's ground sample distance and ease of acquisition. Yet, a combination of platforms and techniques might provide solutions that overcome the weakness of a single platform. To explore the potential for combining platforms, we compared detection bias amongst two 3D remote sensing techniques (lidar and SfM) using three different platforms [ground-based, small unmanned aerial systems (sUAS), and manned aircraft]. We found aerial lidar to be more accurate for characterizing the bare earth (ground) in dense herbaceous vegetation than either terrestrial lidar or aerial SfM photogrammetry. Conversely, the manned aerial lidar did not detect grass and fine woody vegetation while the terrestrial lidar and high resolution near-distance (ground and sUAS) SfM photogrammetry detected these and were accurate. UAS SfM photogrammetry at lower spatial resolution under-estimated maximum heights in grass and shrubs. UAS and handheld SfM photogrammetry in near-distance high resolution collections had similar accuracy to terrestrial lidar for vegetation, but difficulty at measuring bare earth elevation beneath dense herbaceous cover. Combining point cloud data and derivatives (i.e., meshes and rasters) from two or more platforms allowed for more accurate measurement of herbaceous and woody vegetation (height and canopy cover) than any single technique alone. Availability and costs of manned aircraft lidar collection preclude high frequency repeatability but this is less limiting for terrestrial lidar, sUAS and handheld SfM. The post-processing of SfM photogrammetry data became the limiting factor at larger spatial scale and temporal repetition. Despite the utility of sUAS and handheld SfM for monitoring vegetation phenology and structure, their spatial extents are small relative to manned aircraft.

Rapid Topographic Mapping Using TLS and UAV in a Beach-dune-wetland Environment: Case Study in Freeport, Texas, USA

NASA Astrophysics Data System (ADS)

Ding, J.; Wang, G.; Xiong, L.; Zhou, X.; England, E.

2017-12-01

Coastal regions are naturally vulnerable to impact from long-term coastal erosion and episodic coastal hazards caused by extreme weather events. Major geomorphic changes can occur within a few hours during storms. Prediction of storm impact, costal planning and resilience observation after natural events all require accurate and up-to-date topographic maps of coastal morphology. Thus, the ability to conduct rapid and high-resolution-high-accuracy topographic mapping is of critical importance for long-term coastal management and rapid response after natural hazard events. Terrestrial laser scanning (TLS) techniques have been frequently applied to beach and dune erosion studies and post hazard responses. However, TLS surveying is relatively slow and costly for rapid surveying. Furthermore, TLS surveying unavoidably retains gray areas that cannot be reached by laser pulses, particularly in wetland areas where lack of direct access in most cases. Aerial mapping using photogrammetry from images taken by unmanned aerial vehicles (UAV) has become a new technique for rapid topographic mapping. UAV photogrammetry mapping techniques provide the ability to map coastal features quickly, safely, inexpensively, on short notice and with minimal impact. The primary products from photogrammetry are point clouds similar to the LiDAR point clouds. However, a large number of ground control points (ground truth) are essential for obtaining high-accuracy UAV maps. The ground control points are often obtained by GPS survey simultaneously with the TLS survey in the field. The GPS survey could be a slow and arduous process in the field. This study aims to develop methods for acquiring a huge number of ground control points from TLS survey and validating point clouds obtained from photogrammetry with the TLS point clouds. A Rigel VZ-2000 TLS scanner was used for developing laser point clouds and a DJI Phantom 4 Pro UAV was used for acquiring images. The aerial images were processed with the Photogrammetry mapping software Agisoft PhotoScan. A workflow for conducting rapid TLS and UAV survey in the field and integrating point clouds obtained from TLS and UAV surveying will be introduced. Key words: UAV photogrammetry, ground control points, TLS, coastal morphology, topographic mapping

Photogrammetry as a tool for the postural evaluation of the spine: A systematic review.

PubMed

Furlanetto, Tássia Silveira; Sedrez, Juliana Adami; Candotti, Cláudia Tarragô; Loss, Jefferson Fagundes

2016-02-18

To evaluate the use of photogrammetry and identify the mathematical procedures applied when evaluating spinal posture. A systematic search using keywords was conducted in the PubMed, EMBASE, Scopus, Science and Medicine(®) databases. The following inclusion criteria adopted were: (1) the use of photogrammetry as a method to evaluate spinal posture; (2) evaluations of spinal curvature in the sagittal and/or frontal plane; (3) studies published within the last three decades; and (4) written entirely in English. The exclusion criteria were: (1) studies which objective involved the verification of some aspect of validation of instruments; (2) studies published as abstracts and those published in scientific events; and (3) studies using evaluation of the anteriorization of the head to determine the angular positioning of the cervical spine. The articles in this review were included and evaluated for their methodological quality, based on the Downs and Black scale, by two independent reviewers. Initially, 1758 articles were found, 76 of which were included upon reading the full texts and 29 were included in accordance with the predetermined criteria. In addition, after analyzing the references in those articles, a further six articles were selected, so that 35 articles were included in this review. This systematic review revealed that the photogrammetry has been using in observational studies. Furthermore, it was also found that, although the data collection methodologies are similar across the studies, in relation to aspects of data analysis, the methodologies are very different, especially regarding the mathematical routines employed to support different postural evaluation software. With photogrammetry, the aim of the assessment, whether it is for clinical, research or collective health purposes, must be considered when choosing which protocol to use to evaluate spinal posture.

Photogrammetry as a tool for the postural evaluation of the spine: A systematic review

PubMed Central

Furlanetto, Tássia Silveira; Sedrez, Juliana Adami; Candotti, Cláudia Tarragô; Loss, Jefferson Fagundes

2016-01-01

AIM: To evaluate the use of photogrammetry and identify the mathematical procedures applied when evaluating spinal posture. METHODS: A systematic search using keywords was conducted in the PubMed, EMBASE, Scopus, Science and Medicine® databases. The following inclusion criteria adopted were: (1) the use of photogrammetry as a method to evaluate spinal posture; (2) evaluations of spinal curvature in the sagittal and/or frontal plane; (3) studies published within the last three decades; and (4) written entirely in English. The exclusion criteria were: (1) studies which objective involved the verification of some aspect of validation of instruments; (2) studies published as abstracts and those published in scientific events; and (3) studies using evaluation of the anteriorization of the head to determine the angular positioning of the cervical spine. The articles in this review were included and evaluated for their methodological quality, based on the Downs and Black scale, by two independent reviewers. RESULTS: Initially, 1758 articles were found, 76 of which were included upon reading the full texts and 29 were included in accordance with the predetermined criteria. In addition, after analyzing the references in those articles, a further six articles were selected, so that 35 articles were included in this review. This systematic review revealed that the photogrammetry has been using in observational studies. Furthermore, it was also found that, although the data collection methodologies are similar across the studies, in relation to aspects of data analysis, the methodologies are very different, especially regarding the mathematical routines employed to support different postural evaluation software. CONCLUSION: With photogrammetry, the aim of the assessment, whether it is for clinical, research or collective health purposes, must be considered when choosing which protocol to use to evaluate spinal posture. PMID:26925386

Assessment of Soft Tissue Changes by Cephalometry and Two-Dimensional Photogrammetry in Bilateral Sagittal Split Ramus Osteotomy Cases

PubMed Central

Martin, Alice

2011-01-01

ABSTRACT Objectives We aimed to compare the standard methods of cephalometry and two-dimensional photogrammetry, to evaluate the reliability and accuracy of both methods. Material and Methods Twenty-six patients (mean age 25.5, standard deviation (SD) 5.2 years) with Class II relationship and 23 patients with Class III relationship (mean age 26.4, SD 4.7 years) who had undergone bilateral sagittal split ramus osteotomy were selected, with a median follow-up of 8 months between pre- and postsurgical evaluation. Pre- and postsurgical cephalograms and lateral photograms were traced and changes were recorded. Results Pre- and postsurgical measurements of hard tissue angles and distances revealed higher correlations with cephalometrically performed soft tissue measurements of facial convexity (Class II: N-PG, r = - 0.50, P = 0.047; Class III: ANB, r = 0.73, P = 0.005; NaPg , r = 0.71, P = 0.007;) and labiomental angle (Class II: SNB, r = 0.72, P = 0.002; ANB, r = - 0.72, P = 0.002; N-B, r = - 0.68, P = 0.004; ANS-Gn, r = 0.71, P = 0.002; Class III: ANS-Gn, r = 0.65, P = 0.043) compared with two-dimensional photogrammetry. However, two-dimensional photogrammetry revealed higher correlation between lower lip length and cephalometrically assessed angular hard tissue changes (Class II: SNB, r = 0.98, P = 0.007; N-B, r = 0.89, P = 0.037; N-Pg, r = 0.90, P = 0.033; Class III: SNB, r = - 0.54, P = 0.060; NAPg, r = - 0.65, P = 0.041; N-Pg, r = 0.58, P = 0.039). Conclusions Our findings suggest that cephalometry and two-dimensional photogrammetry offer the possibility to complement one another. PMID:24421994

Archaeological Documentation of a Defunct Iraqi Town

NASA Astrophysics Data System (ADS)

Šedina, J.; Pavelka, K.; Housarová, E.

2016-06-01

The subject of this article is the possibilities of the documentation of a defunct town from the Pre-Islamic period to Early Islamic period. This town is located near the town Makhmur in Iraq. The Czech archaeological mission has worked at this dig site. This Cultural Heritage site is threatened by war because in the vicinity are positions of ISIS. For security reasons, the applicability of Pleiades satellite data has been tested. Moreover, this area is a no-fly zone. However, the DTM created from stereo-images was insufficient for the desired application in archeology. The subject of this paper is the testing of the usability of RPAS technology and terrestrial photogrammetry for documentation of the remains of buildings. RPAS is a very fast growing technology that combines the advantages of aerial photogrammetry and terrestrial photogrammetry. A probably defunct church is a sample object.

Active retroreflector with in situ beam analysis to measure the rotational orientation in conjunction with a laser tracker

NASA Astrophysics Data System (ADS)

Hofherr, O.; Wachten, C.; Müller, C.; Reinecke, H.

2013-04-01

High precision optical non-contact position measurement is a key technology in modern engineering. Laser trackers (LT) can determine accurately x-y-z coordinates of passive retroreflectors. Next-generation systems answer the additional need to measure an object`s rotational orientation (pitch, yaw, roll). These devices are based either on photogrammetry or on enhanced retroreflectors. However, photogrammetry relies on costly camera systems and time-consuming image processing. Enhanced retroreflectors analyze the LT`s beam but are restricted in roll angle measurements. In the past we have presented a new method [1][2] to measure all six degrees of freedom in conjunction with a LT. Now we dramatically optimized the method and designed a new prototype, e.g. taking into consideration optical alignment, reduced power loss, highly optimized measuring signals and higher resolution. A method is described that allows compensating the influence of the LT's beam offset during tracking the active retroreflector. We prove the functionality of the active retroreflector with the LT and, furthermore, demonstrate the capability of the system to characterize the tracking behavior of a LT. The measurement range for the incident laser beam is +/-12° with a resolution of 0.6".

Using digital photogrammetry to conduct an anthropometric analysis of wheelchair users.

PubMed

Barros, Helda Oliveira; Soares, Marcelomárcio

2012-01-01

This study deals with using digital photogrammetry to make an anthropometric analysis of wheelchair users. To analyse the data, Digita software was used, which was made available by means of the agreement of the Design Department of the Federal University of Pernambuco--Brazil--with the Department of Ergonomics of the Technical University of Lisbon--Portugal. Data collection involved a random sample of 18 subjects and occurred in the Biomechanics Laboratory of the Maurice of Nassau Faculty, located in Recife, Pernambuco. The methodology applied comprises the steps of Ergonomic Assessment, Configuration of the Data Base, Taking Digital Photographs, Digitalising the Coordinates and Presentation of Results. 15 structural variables related to static anthropometry were analysed, and 4 functional range variables relating to dynamic anthropometry. The results were presented by analysing personal data, classified by gender, ethnicity and age; by functional analysis of the sample, classified by clinical diagnosis, results of assessing the joints, results of the evaluation through motion and postural evaluation; and of the analysis of the anthropometric sample, which indicated for each variable the number of people, the mean, the standard deviation, and the minimum, median and maximum values.

Automatic Geo-location Correction of Satellite Imagery

DTIC Science & Technology

2014-09-25

orientation of large stereo satellite image blocks.," Int. Arch. Photogrammetry and Remote Sensing Spatial Inf. Sci, vol. 39, pp. 209-214, 2012. [6...Coefficient (RPC) model to represent both the internal and external orientation of a satellite image in one Automatic Geo-location Correction of Satellite...Applications of Digital Image Processing VI, vol. 432, 1983. [9] Edward M Mikhail, James S Bethel, and J C McGlone, Introduction to Modern Photogrammetry

Evaluation of the Quality of Action Cameras with Wide-Angle Lenses in Uav Photogrammetry

NASA Astrophysics Data System (ADS)

Hastedt, H.; Ekkel, T.; Luhmann, T.

2016-06-01

The application of light-weight cameras in UAV photogrammetry is required due to restrictions in payload. In general, consumer cameras with normal lens type are applied to a UAV system. The availability of action cameras, like the GoPro Hero4 Black, including a wide-angle lens (fish-eye lens) offers new perspectives in UAV projects. With these investigations, different calibration procedures for fish-eye lenses are evaluated in order to quantify their accuracy potential in UAV photogrammetry. Herewith the GoPro Hero4 is evaluated using different acquisition modes. It is investigated to which extent the standard calibration approaches in OpenCV or Agisoft PhotoScan/Lens can be applied to the evaluation processes in UAV photogrammetry. Therefore different calibration setups and processing procedures are assessed and discussed. Additionally a pre-correction of the initial distortion by GoPro Studio and its application to the photogrammetric purposes will be evaluated. An experimental setup with a set of control points and a prospective flight scenario is chosen to evaluate the processing results using Agisoft PhotoScan. Herewith it is analysed to which extent a pre-calibration and pre-correction of a GoPro Hero4 will reinforce the reliability and accuracy of a flight scenario.

Application of photogrammetry to transforming PIV-acquired velocity fields to a moving-body coordinate system

NASA Astrophysics Data System (ADS)

Nikoueeyan, Pourya; Naughton, Jonathan

2016-11-01

Particle Image Velocimetry is a common choice for qualitative and quantitative characterization of unsteady flows associated with moving bodies (e.g. pitching and plunging airfoils). Characterizing the separated flow behavior is of great importance in understanding the flow physics and developing predictive reduced-order models. In most studies, the model under investigation moves within a fixed camera field-of-view, and vector fields are calculated based on this fixed coordinate system. To better characterize the genesis and evolution of vortical structures in these unsteady flows, the velocity fields need to be transformed into the moving-body frame of reference. Data converted to this coordinate system allow for a more detailed analysis of the flow field using advanced statistical tools. In this work, a pitching NACA0015 airfoil has been used to demonstrate the capability of photogrammetry for such an analysis. Photogrammetry has been used first to locate the airfoil within the image and then to determine an appropriate mask for processing the PIV data. The photogrammetry results are then further used to determine the rotation matrix that transforms the velocity fields to airfoil coordinates. Examples of the important capabilities such a process enables are discussed. P. Nikoueeyan is supported by a fellowship from the University of Wyoming's Engineering Initiative.

Combined application of electron backscatter diffraction and stereo-photogrammetry in fractography studies.

PubMed

Davies, P A; Randle, V

2001-10-01

The main aim of this paper is to report on recent experimental developments that have succeeded in combining electron back-scatter diffraction (EBSD) with stereo-photogrammetry, compared with two other methods for study of fracture surfaces, namely visual fractography analysis in the scanning electron microscope (SEM) and EBSD directly from facets. These approaches will be illustrated with data relating to the cleavage plane orientation analysis in a ferritic and C-Mn steel. It is demonstrated that the combined use of EBSD and stereo-photogrammetry represents a significant advance in the methodology for facet crystallography analysis. The results of point counting from fractograph characterization determined that the proportions of intergranular fracture in C-Mn and ferritic steels were 10.4% and 9.4%, respectively. The crystallographic orientation was determined directly from the fracture surface of a ferritic steel sample and produced an orientation distribution with a clear trend towards the [001] plane. A stereo-photogrammetry technique was validated using the known geometry of a Vickers hardness indent. The technique was then successfully employed to measure the macroscopic orientation of individual cleavage facets in the same reference frame as the EBSD measurements. Correlating the results of these measurements indicated that the actual crystallographic orientation of every cleavage facet identified in the steel specimens is [001].

On the Accuracy Potential in Underwater/Multimedia Photogrammetry.

PubMed

Maas, Hans-Gerd

2015-07-24

Underwater applications of photogrammetric measurement techniques usually need to deal with multimedia photogrammetry aspects, which are characterized by the necessity of handling optical rays that are refracted at interfaces between optical media with different refractive indices according to Snell's Law. This so-called multimedia geometry has to be incorporated into geometric models in order to achieve correct measurement results. The paper shows a flexible yet strict geometric model for the handling of refraction effects on the optical path, which can be implemented as a module into photogrammetric standard tools such as spatial resection, spatial intersection, bundle adjustment or epipolar line computation. The module is especially well suited for applications, where an object in water is observed by cameras in air through one or more planar glass interfaces, as it allows for some simplifications here. In the second part of the paper, several aspects, which are relevant for an assessment of the accuracy potential in underwater/multimedia photogrammetry, are discussed. These aspects include network geometry and interface planarity issues as well as effects caused by refractive index variations and dispersion and diffusion under water. All these factors contribute to a rather significant degradation of the geometric accuracy potential in underwater/multimedia photogrammetry. In practical experiments, a degradation of the quality of results by a factor two could be determined under relatively favorable conditions.

Analysis of the reliability and reproducibility of goniometry compared to hand photogrammetry

PubMed Central

de Carvalho, Rosana Martins Ferreira; Mazzer, Nilton; Barbieri, Claudio Henrique

2012-01-01

Objective: To evaluate the intra- and inter-examiner reliability and reproducibility of goniometry in relation to photogrammetry of hand, comparing the angles of thumb abduction, PIP joint flexion of the II finger and MCP joint flexion of the V finger. Methods: The study included 30 volunteers, who were divided into three groups: one group of 10 physiotherapy students, one group of 10 physiotherapists, and a third group of 10 therapists of the hand. Each examiner performed the measurements on the same hand mold, using the goniometer followed by two photogrammetry software programs; CorelDraw® and ALCimagem®. Results: The results revealed that the groups and the methods proposed presented inter-examiner reliability, generally rated as excellent (ICC 0.998 I.C. 95% 0.995 - 0.999). In the intra-examiner evaluation, an excellent level of reliability was found between the three groups. In the comparison between groups for each angle and each method, no significant differences were found between the groups for most of the measurements. Conclusion: Goniometry and photogrammetry are reliable and reproducible methods for evaluating measurements of the hand. However, due to the lack of similar references, detailed studies are needed to define the normal parameters between the methods in the joints of the hand. Level of Evidence II, Diagnostic Study. PMID:24453594

Application on-line imagery for photogrammetry comparison of natural hazards events

NASA Astrophysics Data System (ADS)

Voumard, Jérémie; Jaboyedoff, Michel; Derron, Marc-Henri

2015-04-01

The airborne (ALS) and terrestrial laser scanner (TLS) technologies are well known and actually one of the most common technics to obtain 3D terrain models. However those technologies are expensive and logistically demanding. Another way to obtain DEM without those inconveniences is photogrammetry, in particular the structure from motion (SfM) technic that allows high quality 3D model extraction from common digital camera images without need of a expensive material. If the usual way to get images for SfM 3D modelling is to take pictures on-site, on-line imagery offer the possibility to get images from many roads and other places. The most common on-line street view resource is Google Street View. Since April 2014, this service proposes a back-in-time function on a certain number of locations. Google Street View images are composed from many pictures taken with a set of panoramic cameras mounted on a platform like a car roof. Those images are affected by strong deformations, which are not recommended for photogrammetry. At first sight, using street view images to make photogrammetry may bring some processing problems. The aim of this project is to study the possibility to made SfM 3D model from Google Street View images with open source processing software (Visual SFM) and low-cost software (Agisoft). The main interest of this method is to evaluate at low cost changes without terrain visit. Study areas are landslides (such those of Séchilienne in France) and cliffs near or far away from roads. Human-made terrain changes like stone wall collapse by high rain precipitations near of Monaco are also studied. For each case, 50 to 200 pictures have been used. The mains conditions to obtain 3D model results are: to have a street view image of the area of interest. Some countries like USA or France are well documented. Other countries like Switzerland are only partially or not at all like Germany. The second constraint is to have two or more sets of images at different time. Third condition is to have enough quality images. Over- or underexposed images, bad meteorological conditions (fog, rain, etc.) or bad images resolution compromise the SfM process. In our case studies, distances from the road to the object of interest range from 1 to 500 m. First results show that SfM processing with on-line images is not obvious. Poor-resolution and deformed images with unknown camera features make the process often difficult and not predictive. The use of Agisoft software give bad results because of the abovementioned features while Visual SFM give interesting results for about two thirds of cases. It is also demonstrated that 3D photogrammetry is possible with on-line images under certain restrictive conditions. Under these conditions of images quality, this technique can then be used to estimate volumes changes.

Hybrid 3D reconstruction and image-based rendering techniques for reality modeling

NASA Astrophysics Data System (ADS)

Sequeira, Vitor; Wolfart, Erik; Bovisio, Emanuele; Biotti, Ester; Goncalves, Joao G. M.

2000-12-01

This paper presents a component approach that combines in a seamless way the strong features of laser range acquisition with the visual quality of purely photographic approaches. The relevant components of the system are: (i) Panoramic images for distant background scenery where parallax is insignificant; (ii) Photogrammetry for background buildings and (iii) High detailed laser based models for the primary environment, structure of exteriors of buildings and interiors of rooms. These techniques have a wide range of applications in visualization, virtual reality, cost effective as-built analysis of architectural and industrial environments, building facilities management, real-estate, E-commerce, remote inspection of hazardous environments, TV production and many others.

Registration of Aerial Optical Images with LiDAR Data Using the Closest Point Principle and Collinearity Equations.

PubMed

Huang, Rongyong; Zheng, Shunyi; Hu, Kun

2018-06-01

Registration of large-scale optical images with airborne LiDAR data is the basis of the integration of photogrammetry and LiDAR. However, geometric misalignments still exist between some aerial optical images and airborne LiDAR point clouds. To eliminate such misalignments, we extended a method for registering close-range optical images with terrestrial LiDAR data to a variety of large-scale aerial optical images and airborne LiDAR data. The fundamental principle is to minimize the distances from the photogrammetric matching points to the terrestrial LiDAR data surface. Except for the satisfactory efficiency of about 79 s per 6732 × 8984 image, the experimental results also show that the unit weighted root mean square (RMS) of the image points is able to reach a sub-pixel level (0.45 to 0.62 pixel), and the actual horizontal and vertical accuracy can be greatly improved to a high level of 1/4⁻1/2 (0.17⁻0.27 m) and 1/8⁻1/4 (0.10⁻0.15 m) of the average LiDAR point distance respectively. Finally, the method is proved to be more accurate, feasible, efficient, and practical in variety of large-scale aerial optical image and LiDAR data.

a Method of 3d Measurement and Reconstruction for Cultural Relics in Museums

NASA Astrophysics Data System (ADS)

Zheng, S.; Zhou, Y.; Huang, R.; Zhou, L.; Xu, X.; Wang, C.

2012-07-01

Three-dimensional measurement and reconstruction during conservation and restoration of cultural relics have become an essential part of a modem museum regular work. Although many kinds of methods including laser scanning, computer vision and close-range photogrammetry have been put forward, but problems still exist, such as contradiction between cost and good result, time and fine effect. Aimed at these problems, this paper proposed a structure-light based method for 3D measurement and reconstruction of cultural relics in museums. Firstly, based on structure-light principle, digitalization hardware has been built and with its help, dense point cloud of cultural relics' surface can be easily acquired. To produce accurate 3D geometry model from point cloud data, multi processing algorithms have been developed and corresponding software has been implemented whose functions include blunder detection and removal, point cloud alignment and merge, 3D mesh construction and simplification. Finally, high-resolution images are captured and the alignment of these images and 3D geometry model is conducted and realistic, accurate 3D model is constructed. Based on such method, a complete system including hardware and software are built. Multi-kinds of cultural relics have been used to test this method and results prove its own feature such as high efficiency, high accuracy, easy operation and so on.

Photogrammetry and Laser Imagery Tests for Tank Waste Volume Estimates: Summary Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Field, Jim G.

2013-03-27

Feasibility tests were conducted using photogrammetry and laser technologies to estimate the volume of waste in a tank. These technologies were compared with video Camera/CAD Modeling System (CCMS) estimates; the current method used for post-retrieval waste volume estimates. This report summarizes test results and presents recommendations for further development and deployment of technologies to provide more accurate and faster waste volume estimates in support of tank retrieval and closure.

Automation in photogrammetry: Recent developments and applications (1972-1976)

USGS Publications Warehouse

Thompson, M.M.; Mikhail, E.M.

1976-01-01

An overview of recent developments in the automation of photogrammetry in various countries is presented. Conclusions regarding automated photogrammetry reached at the 1972 Congress in Ottawa are reviewed first as a background for examining the developments of 1972-1976. Applications are described for each country reporting significant developments. Among fifteen conclusions listed are statements concerning: the widespread practice of equipping existing stereoplotters with simple digitizers; the growing tendency to use minicomputers on-line with stereoplotters; the optimization of production of digital terrain models by progressive sampling in stereomodels; the potential of digitization of a photogrammetric model by density correlation on epipolar lines; the capabilities and economic aspects of advanced systems which permit simultaneous production of orthophotos, contours, and digital terrain models; the economy of off-line orthophoto systems; applications of digital image processing; automation by optical techniques; applications of sensors other than photographic imagery, and the role of photogrammetric phases in a completely automated cartographic system. ?? 1976.

Method for the visualization of landform by mapping using low altitude UAV application

NASA Astrophysics Data System (ADS)

Sharan Kumar, N.; Ashraf Mohamad Ismail, Mohd; Sukor, Nur Sabahiah Abdul; Cheang, William

2018-05-01

Unmanned Aerial Vehicle (UAV) and Digital Photogrammetry are evolving drastically in mapping technology. The significance and necessity for digital landform mapping are developing with years. In this study, a mapping workflow is applied to obtain two different input data sets which are the orthophoto and DSM. A fine flying technology is used to capture Low Altitude Aerial Photography (LAAP). Low altitude UAV (Drone) with the fixed advanced camera was utilized for imagery while computerized photogrammetry handling using Photo Scan was applied for cartographic information accumulation. The data processing through photogrammetry and orthomosaic processes is the main applications. High imagery quality is essential for the effectiveness and nature of normal mapping output such as 3D model, Digital Elevation Model (DEM), Digital Surface Model (DSM) and Ortho Images. The exactitude of Ground Control Points (GCP), flight altitude and the resolution of the camera are essential for good quality DEM and Orthophoto.

Application of composite small calibration objects in traffic accident scene photogrammetry.

PubMed

Chen, Qiang; Xu, Hongguo; Tan, Lidong

2015-01-01

In order to address the difficulty of arranging large calibration objects and the low measurement accuracy of small calibration objects in traffic accident scene photogrammetry, a photogrammetric method based on a composite of small calibration objects is proposed. Several small calibration objects are placed around the traffic accident scene, and the coordinate system of the composite calibration object is given based on one of them. By maintaining the relative position and coplanar relationship of the small calibration objects, the local coordinate system of each small calibration object is transformed into the coordinate system of the composite calibration object. The two-dimensional direct linear transformation method is improved based on minimizing the reprojection error of the calibration points of all objects. A rectified image is obtained using the nonlinear optimization method. The increased accuracy of traffic accident scene photogrammetry using a composite small calibration object is demonstrated through the analysis of field experiments and case studies.

American Society of Photogrammetry and American Congress on Surveying and Mapping, Fall Technical Meeting, ASP Technical Papers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1981-01-01

Various topics in the field of photogrammetry are addressed. Among the subjects discussed are: remote sensing of Gulf Stream dynamics using VHRR satellite imagery an interactive rectification system for remote sensing imagery use of a single photo and digital terrain matrix for point positioning crop type analysis using Landsat digital data use of a fisheye lens in solar energy assessment remote sensing inventory of Rocky Mountain elk habitat Washington state's large scale ortho program educational image processing. Also discussed are: operational advantages of on-line photogrammetric triangulation analysis of fracturation field photogrammetry as a tool for measuring glacier movement double modelmore » orthophotos used for forest inventory mapping map revisioning module for the Kern PG2 stereoplotter assessing accuracy of digital land-use and terrain data accuracy of earthwork calculations from digital elevation data.« less

Method for Correcting Control Surface Angle Measurements in Single Viewpoint Photogrammetry

NASA Technical Reports Server (NTRS)

Burner, Alpheus W. (Inventor); Barrows, Danny A. (Inventor)

2006-01-01

A method of determining a corrected control surface angle for use in single viewpoint photogrammetry to correct control surface angle measurements affected by wing bending. First and second visual targets are spaced apart &om one another on a control surface of an aircraft wing. The targets are positioned at a semispan distance along the aircraft wing. A reference target separation distance is determined using single viewpoint photogrammetry for a "wind off condition. An apparent target separation distance is then computed for "wind on." The difference between the reference and apparent target separation distances is minimized by recomputing the single viewpoint photogrammetric solution for incrementally changed values of target semispan distances. A final single viewpoint photogrammetric solution is then generated that uses the corrected semispan distance that produced the minimized difference between the reference and apparent target separation distances. The final single viewpoint photogrammetric solution set is used to determine the corrected control surface angle.

Patient Registration Using Photogrammetric Surface Reconstruction from Smartphone Imagery

NASA Astrophysics Data System (ADS)

Hellwich, O.; Rose, A.; Bien, T.; Malolepszy, C.; Mucha, D.; Krüger, T.

2016-06-01

In navigated surgery the patient's body has to be co-registered with presurgically acquired 3D data in order to enable navigation of the surgical instrument. For this purpose the body surface of the patient can be acquired by means of photogrammetry and co-registered to corresponding surfaces in the presurgical data. In this paper this task is exemplarily solved for 3D data of human heads using the face surface to establish correspondence. We focus on investigation of achieved geometric accuracies reporting positioning errors in the range of 1 mm.

Mapping and localization for extraterrestrial robotic explorations

NASA Astrophysics Data System (ADS)

Xu, Fengliang

In the exploration of an extraterrestrial environment such as Mars, orbital data, such as high-resolution imagery Mars Orbital Camera-Narrow Angle (MOC-NA), laser ranging data Mars Orbital Laser Altimeter (MOLA), and multi-spectral imagery Thermal Emission Imaging System (THEMIS), play more and more important roles. However, these remote sensing techniques can never replace the role of landers and rovers, which can provide a close up and inside view. Similarly, orbital mapping can not compete with ground-level close-range mapping in resolution, precision, and speed. This dissertation addresses two tasks related to robotic extraterrestrial exploration: mapping and rover localization. Image registration is also discussed as an important aspect for both of them. Techniques from computer vision and photogrammetry are applied for automation and precision. Image registration is classified into three sub-categories: intra-stereo, inter-stereo, and cross-site, according to the relationship between stereo images. In the intra-stereo registration, which is the most fundamental sub-category, interest point-based registration and verification by parallax continuity in the principal direction are proposed. Two other techniques, inter-scanline search with constrained dynamic programming for far range matching and Markov Random Field (MRF) based registration for big terrain variation, are explored as possible improvements. Creating using rover ground images mainly involves the generation of Digital Terrain Model (DTM) and ortho-rectified map (orthomap). The first task is to derive the spatial distribution statistics from the first panorama and model the DTM with a dual polynomial model. This model is used for interpolation of the DTM, using Kriging in the close range and Triangular Irregular Network (TIN) in the far range. To generate a uniformly illuminated orthomap from the DTM, a least-squares-based automatic intensity balancing method is proposed. Finally a seamless orthomap is constructed by a split-and-merge technique: the mapped area is split or subdivided into small regions of image overlap, and then each small map piece was processed and all of the pieces are merged together to form a seamless map. Rover localization has three stages, all of which use a least-squares adjustment procedure: (1) an initial localization which is accomplished by adjustment over features common to rover images and orbital images, (2) an adjustment of image pointing angles at a single site through inter and intra-stereo tie points, and (3) an adjustment of the rover traverse through manual cross-site tie points. The first stage is based on adjustment of observation angles of features. The second stage and third stage are based on bundle-adjustment. In the third-stage an incremental adjustment method was proposed. Automation in rover localization includes automatic intra/inter-stereo tie point selection, computer-assisted cross-site tie point selection, and automatic verification of accuracy. (Abstract shortened by UMI.)

Modeling human faces with multi-image photogrammetry

NASA Astrophysics Data System (ADS)

D'Apuzzo, Nicola

2002-03-01

Modeling and measurement of the human face have been increasing by importance for various purposes. Laser scanning, coded light range digitizers, image-based approaches and digital stereo photogrammetry are the used methods currently employed in medical applications, computer animation, video surveillance, teleconferencing and virtual reality to produce three dimensional computer models of the human face. Depending on the application, different are the requirements. Ours are primarily high accuracy of the measurement and automation in the process. The method presented in this paper is based on multi-image photogrammetry. The equipment, the method and results achieved with this technique are here depicted. The process is composed of five steps: acquisition of multi-images, calibration of the system, establishment of corresponding points in the images, computation of their 3-D coordinates and generation of a surface model. The images captured by five CCD cameras arranged in front of the subject are digitized by a frame grabber. The complete system is calibrated using a reference object with coded target points, which can be measured fully automatically. To facilitate the establishment of correspondences in the images, texture in the form of random patterns can be projected from two directions onto the face. The multi-image matching process, based on a geometrical constrained least squares matching algorithm, produces a dense set of corresponding points in the five images. Neighborhood filters are then applied on the matching results to remove the errors. After filtering the data, the three-dimensional coordinates of the matched points are computed by forward intersection using the results of the calibration process; the achieved mean accuracy is about 0.2 mm in the sagittal direction and about 0.1 mm in the lateral direction. The last step of data processing is the generation of a surface model from the point cloud and the application of smooth filters. Moreover, a color texture image can be draped over the model to achieve a photorealistic visualization. The advantage of the presented method over laser scanning and coded light range digitizers is the acquisition of the source data in a fraction of a second, allowing the measurement of human faces with higher accuracy and the possibility to measure dynamic events like the speech of a person.

Publication aspects of ethics in photogrammetry

USGS Publications Warehouse

Thompson, Morris M.

1991-01-01

According to the Code of Ethics of the American Society for Photogrammetry and Remote Sensing (ASPRS), the principles on which ethics are founded consist of honesty, justice, and courtesy, forming a moral philosophy associated with mutual interest among men. We will cover in particular the ethical problems of publication of photogrammetric material in the various media. There are many such problems, and we often face a dilemma in selecting a course which is the right thing to do.

On the Accuracy Potential in Underwater/Multimedia Photogrammetry

PubMed Central

Maas, Hans-Gerd

2015-01-01

Underwater applications of photogrammetric measurement techniques usually need to deal with multimedia photogrammetry aspects, which are characterized by the necessity of handling optical rays that are refracted at interfaces between optical media with different refractive indices according to Snell’s Law. This so-called multimedia geometry has to be incorporated into geometric models in order to achieve correct measurement results. The paper shows a flexible yet strict geometric model for the handling of refraction effects on the optical path, which can be implemented as a module into photogrammetric standard tools such as spatial resection, spatial intersection, bundle adjustment or epipolar line computation. The module is especially well suited for applications, where an object in water is observed by cameras in air through one or more planar glass interfaces, as it allows for some simplifications here. In the second part of the paper, several aspects, which are relevant for an assessment of the accuracy potential in underwater/multimedia photogrammetry, are discussed. These aspects include network geometry and interface planarity issues as well as effects caused by refractive index variations and dispersion and diffusion under water. All these factors contribute to a rather significant degradation of the geometric accuracy potential in underwater/multimedia photogrammetry. In practical experiments, a degradation of the quality of results by a factor two could be determined under relatively favorable conditions. PMID:26213942

Comparison of parameters of spinal curves in the sagittal plane measured by photogrammetry and inclinometry.

PubMed

Walicka-Cupryś, Katarzyna; Drzał-Grabiec, Justyna; Mrozkowiak, Mirosław

2013-10-31

BACKGROUND. The photogrammetric method and inclinometer-based measurements are commonly employed to assess the anteroposterior curvatures of the spine. These methods are used both in clinical trials and for screening purposes. The aim of the study was to compare the parameters used to characterise the anteroposterior spinal curvatures as measured by photogrammetry and inclinometry. MATERIAL AND METHODS. The study enrolled 341 subjects: 169 girls and 172 boys, aged 4 to 9 years, from kindergartens and primary schools in Rzeszów. The anteroposterior spinal curvatures were examined by photogrammetry and with a mechanical inclinometer. RESULTS. There were significant differences in the α angle between the inclinometric and photogrammetric assessment in the Student t test (p=0.017) and the Fisher Snedecor test (p=0.0001), with similar differences in the β angle (Student's t p=0.0001, Fisher Snedecor p=0.007). For the γ angle, significant differences were revealed with Student's t test (p=0.0001), but not with the Fisher Snedecor test (p = 0.22). CONCLUSIONS. 1. Measurements of inclination of particular segments of the spine obtained with the photogrammetric method and the inclinometric method in the same study group revealed statistically significant differences. 2. The results of measurements obtained by photogrammetry and inclinometry are not comparable. 3. Further research on agreement between measurements of the anteroposterior spinal curvatures obtained using the available measurement equipment is recommended.

Reliability and validity of the photogrammetry for scoliosis evaluation: a cross-sectional prospective study.

PubMed

Saad, Karen Ruggeri; Colombo, Alexandra S; João, Silvia M Amado

2009-01-01

The purpose of this study was to investigate the reliability and validity of photogrammetry in measuring the lateral spinal inclination angles. Forty subjects (32 female and 8 males) with a mean age of 23.4 +/- 11.2 years had their scoliosis evaluated by radiographs of their trunk, determined by the Cobb angle method, and by photogrammetry. The statistical methods used included Cronbach alpha, Pearson/Spearman correlation coefficients, and regression analyses. The Cronbach alpha values showed that the photogrammetric measures showed high internal consistency, which indicated that the sample was bias free. The radiograph method showed to be more precise with intrarater reliabilities of 0.936, 0.975, and 0.945 for the thoracic, lumbar, and thoracolumbar curves, respectively, and interrater reliabilities of 0.942 and 0.879 for the angular measures of the thoracic and thoracolumbar segments, respectively. The regression analyses revealed a high determination coefficient although limited to the adjusted linear model between the radiographic and photographic measures. It was found that with more severe scoliosis, the lateral curve measures obtained with the photogrammetry were for the thoracic and lumbar regions (R = 0.619 and 0.551). The photogrammetric measures were found to be reproducible in this study and could be used as supplementary information to decrease the number of radiographs necessary for the monitoring of scoliosis.

Computerized photogrammetry used to calculate the brow position index.

PubMed

Naif-de-Andrade, Naif Thadeu; Hochman, Bernardo; Naif-de-Andrade, Camila Zirlis; Ferreira, Lydia Masako

2012-10-01

The orbital region is of vital importance to facial expression. Brow ptosis, besides having an impact on facial harmony, is a sign of aging. Various surgical techniques have been developed to increase the efficacy of brow-lift surgery. However, no consensus method exists for an objective measurement of the eyebrow position due to the curvature of the face. Therefore, this study aimed to establish a method for measuring the eyebrow position using computerized photogrammetry. For this study, 20 orbital regions of 10 volunteers were measured by direct anthropometry using a digital caliper and by indirect anthropometry (computerized photogrammetry) using standardized digital photographs. Lines, points, and distances were defined based on the position of the anthropometric landmarks endocanthion and exocanthion and then used to calculate the brow position index (BPI). Statistical analysis was performed using Student's t test with a significance level of 5 %. The BPI values obtained by computerized photogrammetric measurements did not differ significantly from those obtained by direct anthropometric measurements (p > 0.05). The mean BPI was 84.89 ± 10.30 for the computerized photogrammetric measurements and 85.27 ± 10.67 for the direct anthropometric measurements. The BPI defined in this study and obtained by computerized photogrammetry is a reproducible and efficient method for measuring the eyebrow position. This journal requires that authors assign a level of evidence to each article.

UAS Photogrammetry for Rapid Response Characterization of Subaerial Coastal Change

NASA Astrophysics Data System (ADS)

Do, C.; Anarde, K.; Figlus, J.; Prouse, W.; Bedient, P. B.

2016-12-01

Unmanned aerial systems (UASs) provide an exciting new platform for rapid response measurement of subaerial coastal change. Here we validate the use of a coupled hobbyist UAS and optical photogrammetry framework for high-resolution mapping of portions of a low-lying barrier island along the Texas Gulf Coast. A DJI Phantom 3 Professional was used to capture 2D nadir images of the foreshore and back-beach environments containing both vegetated and non-vegetated features. The images were georeferenced using ground-truth markers surveyed via real-time kinematic (RTK) GPS and were then imported into Agisoft Photoscan, a photo-processing software, to generate 3D point clouds and digital elevation maps (DEMs). The georeferenced elevation models were then compared to RTK measurements to evaluate accuracy and precision. Thus far, DEMs derived from UAS photogrammetry show centimeter resolution for renderings of non-vegetated landforms. High-resolution renderings of vegetated and back-barrier regions have proven more difficult due to interstitial wetlands (surface reflectance) and uneven terrain for GPS backpack surveys. In addition to producing high-quality models, UAS photogrammetry has demonstrated to be more time-efficient than traditional mapping methods, making it advantageous for rapid response deployments. This study is part of a larger effort to relate field measurements of storm hydrodynamics to subaerial evidence of geomorphic change to better understand barrier island response to extreme storms.

Fold-Thrust mapping using photogrammetry in Western Champsaur basin, SE France

NASA Astrophysics Data System (ADS)

Totake, Y.; Butler, R.; Bond, C. E.

2016-12-01

There is an increasing demand for high-resolution geometric data for outcropping geological structures - not only to test models for their formation and evolution but also to create synthetic seismic visualisations for comparison with subsurface data. High-resolution 3D scenes reconstructed by modern photogrammetry offer an efficient toolbox for such work. When integrated with direct field measurements and observations, these products can be used to build geological interpretations and models. Photogrammetric techniques using standard equipment are ideally suited to working in the high mountain terrain that commonly offers the best outcrops, as all equipment is readily portable and, in the absence of cloud-cover, not restricted to the meteorological and legal restrictions that can affect some airborne approaches. The workflows and approaches for generating geological models utilising such photogrammetry techniques are the focus of our contribution. Our case study comes from SE France where early Alpine fore-deep sediments have been deformed into arrays of fold-thrust complexes. Over 1500m vertical relief provides excellent outcrop control with surrounding hillsides providing vantage points for ground-based photogrammetry. We collected over 9,400 photographs across the fold-thrust array using a handheld digital camera from 133 ground locations that were individually georeferenced. We processed the photographic images within the software PhotoScan-Pro to build 3D landscape scenes. The built photogrammetric models were then imported into the software Move, along with field measurements, to map faults and sedimentary layers and to produce geological cross sections and 3D geological surfaces. Polylines of sediment beds and faults traced on our photogrammetry models allow interpretation of a pseudo-3D geometry of the deformation structures, and enable prediction of dips and strikes from inaccessible field areas, to map the complex geometries of the thrust faults and deformed strata in detail. The resultant structural geometry of the thrust zones delivers an exceptional analogue to inaccessible subsurface fold-thrust structures which are often challenging to obtain a clear seismic image.

Spectral features based tea garden extraction from digital orthophoto maps

NASA Astrophysics Data System (ADS)

Jamil, Akhtar; Bayram, Bulent; Kucuk, Turgay; Zafer Seker, Dursun

2018-05-01

The advancements in the photogrammetry and remote sensing technologies has made it possible to extract useful tangible information from data which plays a pivotal role in various application such as management and monitoring of forests and agricultural lands etc. This study aimed to evaluate the effectiveness of spectral signatures for extraction of tea gardens from 1 : 5000 scaled digital orthophoto maps obtained from Rize city in Turkey. First, the normalized difference vegetation index (NDVI) was derived from the input images to suppress the non-vegetation areas. NDVI values less than zero were discarded and the output images was normalized in the range 0-255. Individual pixels were then mapped into meaningful objects using global region growing technique. The resulting image was filtered and smoothed to reduce the impact of noise. Furthermore, geometrical constraints were applied to remove small objects (less than 500 pixels) followed by morphological opening operator to enhance the results. These objects served as building blocks for further image analysis. Finally, for the classification stage, a range of spectral values were empirically calculated for each band and applied on candidate objects to extract tea gardens. For accuracy assessment, we employed an area based similarity metric by overlapping obtained tea garden boundaries with the manually digitized tea garden boundaries created by experts of photogrammetry. The overall accuracy of the proposed method scored 89 % for tea gardens from 10 sample orthophoto maps. We concluded that exploiting the spectral signatures using object based analysis is an effective technique for extraction of dominant tree species from digital orthophoto maps.

Study of multi-functional precision optical measuring system for large scale equipment

NASA Astrophysics Data System (ADS)

Jiang, Wei; Lao, Dabao; Zhou, Weihu; Zhang, Wenying; Jiang, Xingjian; Wang, Yongxi

2017-10-01

The effective application of high performance measurement technology can greatly improve the large-scale equipment manufacturing ability. Therefore, the geometric parameters measurement, such as size, attitude and position, requires the measurement system with high precision, multi-function, portability and other characteristics. However, the existing measuring instruments, such as laser tracker, total station, photogrammetry system, mostly has single function, station moving and other shortcomings. Laser tracker needs to work with cooperative target, but it can hardly meet the requirement of measurement in extreme environment. Total station is mainly used for outdoor surveying and mapping, it is hard to achieve the demand of accuracy in industrial measurement. Photogrammetry system can achieve a wide range of multi-point measurement, but the measuring range is limited and need to repeatedly move station. The paper presents a non-contact opto-electronic measuring instrument, not only it can work by scanning the measurement path but also measuring the cooperative target by tracking measurement. The system is based on some key technologies, such as absolute distance measurement, two-dimensional angle measurement, automatically target recognition and accurate aiming, precision control, assembly of complex mechanical system and multi-functional 3D visualization software. Among them, the absolute distance measurement module ensures measurement with high accuracy, and the twodimensional angle measuring module provides precision angle measurement. The system is suitable for the case of noncontact measurement of large-scale equipment, it can ensure the quality and performance of large-scale equipment throughout the process of manufacturing and improve the manufacturing ability of large-scale and high-end equipment.

The Creation of Space Vector Models of Buildings From RPAS Photogrammetry Data

NASA Astrophysics Data System (ADS)

Trhan, Ondrej

2017-06-01

The results of Remote Piloted Aircraft System (RPAS) photogrammetry are digital surface models and orthophotos. The main problem of the digital surface models obtained is that buildings are not perpendicular and the shape of roofs is deformed. The task of this paper is to obtain a more accurate digital surface model using building reconstructions. The paper discusses the problem of obtaining and approximating building footprints, reconstructing the final spatial vector digital building model, and modifying the buildings on the digital surface model.

ROLES OF REMOTE SENSING AND CARTOGRAPHY IN THE USGS NATIONAL MAPPING DIVISION.

USGS Publications Warehouse

Southard, Rupert B.; Salisbury, John W.

1983-01-01

The inseparable roles of remote sensing and photogrammetry have been recognized to be consistent with the aims and interests of the American Society of Photogrammetry. In particular, spatial data storage, data merging and manipulation methods and other techniques originally developed for remote sensing applications also have applications for digital cartography. Also, with the introduction of much improved digital processing techniques, even relatively low resolution (80 m) traditional Landsat images can now be digitally mosaicked into excellent quality 1:250,000-scale image maps.

Photogrammetry and computer-aided piping design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keneflick, J.F.; Chirillo, R.D.

1985-02-18

Three-dimensional measurements taken from photographs of a plant model can be digitized and linked with computer-aided piping design. This can short-cut the design and construction of new plants and expedite repair and retrofitting projects. Some designers bridge the gap between model and computer by digitizing from orthographic prints obtained via orthography or the laser scanning of model sections. Such valve or fitting then processed is described in this paper. The marriage of photogrammetry and computer-aided piping design can economically produce such numerical drawings.

The ISPRS Student Consortium: From launch to tenth anniversary

NASA Astrophysics Data System (ADS)

Kanjir, U.; Detchev, I.; Reyes, S. R.; Akkartal Aktas, A.; Lo, C. Y.; Miyazaki, H.

2014-04-01

The ISPRS Student Consortium is an international organization for students and young professionals in the fields of photogrammetry, remote sensing, and the geospatial information sciences. Since its start ten years ago, the number of members of the Student Consortium has been steadily growing, now reaching close to 1000. Its increased popularity, especially in recent years, is mainly due to the organization's worldwide involvement in student matters. The Student Consortium has helped organize numerous summer schools, youth forums, and student technical sessions at ISPRS sponsored conferences. In addition, the organization publishes a newsletter, and hosts several social media outlets in order to keep its global membership up-to-date on a regular basis. This paper will describe the structure of the organization, and it will give some example of its past student related activities.

Automatic extraction of building boundaries using aerial LiDAR data

NASA Astrophysics Data System (ADS)

Wang, Ruisheng; Hu, Yong; Wu, Huayi; Wang, Jian

2016-01-01

Building extraction is one of the main research topics of the photogrammetry community. This paper presents automatic algorithms for building boundary extractions from aerial LiDAR data. First, segmenting height information generated from LiDAR data, the outer boundaries of aboveground objects are expressed as closed chains of oriented edge pixels. Then, building boundaries are distinguished from nonbuilding ones by evaluating their shapes. The candidate building boundaries are reconstructed as rectangles or regular polygons by applying new algorithms, following the hypothesis verification paradigm. These algorithms include constrained searching in Hough space, enhanced Hough transformation, and the sequential linking technique. The experimental results show that the proposed algorithms successfully extract building boundaries at rates of 97%, 85%, and 92% for three LiDAR datasets with varying scene complexities.

An accurate and adaptable photogrammetric approach for estimating the mass and body condition of pinnipeds using an unmanned aerial system

PubMed Central

Hinke, Jefferson T.; Perryman, Wayne L.; Goebel, Michael E.; LeRoi, Donald J.

2017-01-01

Measurements of body size and mass are fundamental to pinniped population management and research. Manual measurements tend to be accurate but are invasive and logistically challenging to obtain. Ground-based photogrammetric techniques are less invasive, but inherent limitations make them impractical for many field applications. The recent proliferation of unmanned aerial systems (UAS) in wildlife monitoring has provided a promising new platform for the photogrammetry of free-ranging pinnipeds. Leopard seals (Hydrurga leptonyx) are an apex predator in coastal Antarctica whose body condition could be a valuable indicator of ecosystem health. We aerially surveyed leopard seals of known body size and mass to test the precision and accuracy of photogrammetry from a small UAS. Flights were conducted in January and February of 2013 and 2014 and 50 photogrammetric samples were obtained from 15 unrestrained seals. UAS-derived measurements of standard length were accurate to within 2.01 ± 1.06%, and paired comparisons with ground measurements were statistically indistinguishable. An allometric linear mixed effects model predicted leopard seal mass within 19.40 kg (4.4% error for a 440 kg seal). Photogrammetric measurements from a single, vertical image obtained using UAS provide a noninvasive approach for estimating the mass and body condition of pinnipeds that may be widely applicable. PMID:29186134

An accurate and adaptable photogrammetric approach for estimating the mass and body condition of pinnipeds using an unmanned aerial system.

PubMed

Krause, Douglas J; Hinke, Jefferson T; Perryman, Wayne L; Goebel, Michael E; LeRoi, Donald J

2017-01-01

Measurements of body size and mass are fundamental to pinniped population management and research. Manual measurements tend to be accurate but are invasive and logistically challenging to obtain. Ground-based photogrammetric techniques are less invasive, but inherent limitations make them impractical for many field applications. The recent proliferation of unmanned aerial systems (UAS) in wildlife monitoring has provided a promising new platform for the photogrammetry of free-ranging pinnipeds. Leopard seals (Hydrurga leptonyx) are an apex predator in coastal Antarctica whose body condition could be a valuable indicator of ecosystem health. We aerially surveyed leopard seals of known body size and mass to test the precision and accuracy of photogrammetry from a small UAS. Flights were conducted in January and February of 2013 and 2014 and 50 photogrammetric samples were obtained from 15 unrestrained seals. UAS-derived measurements of standard length were accurate to within 2.01 ± 1.06%, and paired comparisons with ground measurements were statistically indistinguishable. An allometric linear mixed effects model predicted leopard seal mass within 19.40 kg (4.4% error for a 440 kg seal). Photogrammetric measurements from a single, vertical image obtained using UAS provide a noninvasive approach for estimating the mass and body condition of pinnipeds that may be widely applicable.

Technical Aspects Related to the Application of SFM Photogrammetry in High Mountain

NASA Astrophysics Data System (ADS)

Scaioni, M.; Crippa, J.; Corti, M.; Barazzetti, L.; Fugazza, D.; Azzoni, R.; Cernuschi, M.; Diolaiuti, G. A.

2018-05-01

Structure-from-Motion (SfM) photogrammetry is a flexible and powerful tool to provide 3D point clouds describing the surface of objects. Due to the easy transportability and low-cost of necessary equipment with respect to laser scanning techniques, SfM photogrammetry has great potential to be applied in harsh high-mountain environment. Here point clouds and derived by-products (DEM's, orthoimages, Virtual-Reality models) are needed to document surface morphology and to investigate dynamic processes such as landslides, avalanches, river and soil erosion, glacier retreat. On the other hand, from both the literature and the direct experience of the authors, there are some technical issues that still deserve thorough investigations. The paper would like to address some open problems and suggest solutions, in particular on regards of the photogrammetric network design, the strategy for georeferencing the final products, and for their comparison within time. The discussion is documented with some examples, mainly from surveying campaigns at the Forni Glacier in Italian Alps.

Research on the electro-optical assistant landing system based on the dual camera photogrammetry algorithm

NASA Astrophysics Data System (ADS)

Mi, Yuhe; Huang, Yifan; Li, Lin

2015-08-01

Based on the location technique of beacon photogrammetry, Dual Camera Photogrammetry (DCP) algorithm was used to assist helicopters landing on the ship. In this paper, ZEMAX was used to simulate the two Charge Coupled Device (CCD) cameras imaging four beacons on both sides of the helicopter and output the image to MATLAB. Target coordinate systems, image pixel coordinate systems, world coordinate systems and camera coordinate systems were established respectively. According to the ideal pin-hole imaging model, the rotation matrix and translation vector of the target coordinate systems and the camera coordinate systems could be obtained by using MATLAB to process the image information and calculate the linear equations. On the basis mentioned above, ambient temperature and the positions of the beacons and cameras were changed in ZEMAX to test the accuracy of the DCP algorithm in complex sea status. The numerical simulation shows that in complex sea status, the position measurement accuracy can meet the requirements of the project.

Advantages of High Tolerance Measurements in Fusion Environments Applying Photogrammetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

T. Dodson, R. Ellis, C. Priniski, S. Raftopoulos, D. Stevens, M. Viola

2009-02-04

Photogrammetry, a state-of-the-art technique of metrology employing digital photographs as the vehicle for measurement, has been investigated in the fusion environment. Benefits of this high tolerance methodology include relatively easy deployment for multiple point measurements and deformation/distortion studies. Depending on the equipment used, photogrammetric systems can reach tolerances of 25 microns (0.001 in) to 100 microns (0.004 in) on a 3-meter object. During the fabrication and assembly of the National Compact Stellarator Experiment (NCSX) the primary measurement systems deployed were CAD coordinate-based computer metrology equipment and supporting algorithms such as both interferometer-aided (IFM) and absolute distance measurementbased (ADM) laser trackers,more » as well as portable Coordinate Measurement Machine (CMM) arms. Photogrammetry was employed at NCSX as a quick and easy tool to monitor coil distortions incurred during welding operations of the machine assembly process and as a way to reduce assembly downtime for metrology processes.« less

Volumetric measurement of rock movement using photogrammetry

PubMed Central

Benton, Donovan J.; Iverson, Stephen R.; Martin, Lewis A.; Johnson, Jeffrey C.; Raffaldi, Michael J.

2016-01-01

NIOSH ground control safety research program at Spokane, Washington, is exploring applications of photogrammetry to rock mass and support monitoring. This paper describes two ways photogrammetric techniques are being used. First, photogrammetric data of laboratory testing is being used to correlate energy input and support deformation. This information can be used to infer remaining support toughness after ground deformation events. This technique is also demonstrated in a field application. Second, field photogrammetric data is compared to crackmeter data from a deep underground mine. Accuracies were found to average 8 mm, but have produced results within 0.2 mm of true displacement, as measured by crackmeters. Application of these techniques consists of monitoring overall fault activity by monitoring multiple points around the crackmeter. A case study is provided in which a crackmeter is clearly shown to have provided insufficient information regarding overall fault ground deformation. Photogrammetry is proving to be a useful ground monitoring tool due to its unobtrusiveness and ease of use. PMID:27110429

Application of Composite Small Calibration Objects in Traffic Accident Scene Photogrammetry

PubMed Central

Chen, Qiang; Xu, Hongguo; Tan, Lidong

2015-01-01

In order to address the difficulty of arranging large calibration objects and the low measurement accuracy of small calibration objects in traffic accident scene photogrammetry, a photogrammetric method based on a composite of small calibration objects is proposed. Several small calibration objects are placed around the traffic accident scene, and the coordinate system of the composite calibration object is given based on one of them. By maintaining the relative position and coplanar relationship of the small calibration objects, the local coordinate system of each small calibration object is transformed into the coordinate system of the composite calibration object. The two-dimensional direct linear transformation method is improved based on minimizing the reprojection error of the calibration points of all objects. A rectified image is obtained using the nonlinear optimization method. The increased accuracy of traffic accident scene photogrammetry using a composite small calibration object is demonstrated through the analysis of field experiments and case studies. PMID:26011052

Using unmanned aerial vehicles and structure-from-motion photogrammetry to characterize sedimentary outcrops: An example from the Morrison Formation, Utah, USA

NASA Astrophysics Data System (ADS)

Chesley, J. T.; Leier, A. L.; White, S.; Torres, R.

2017-06-01

Recently developed data collection techniques allow for improved characterization of sedimentary outcrops. Here, we outline a workflow that utilizes unmanned aerial vehicles (UAV) and structure-from-motion (SfM) photogrammetry to produce sub-meter-scale outcrop reconstructions in 3-D. SfM photogrammetry uses multiple overlapping images and an image-based terrain extraction algorithm to reconstruct the location of individual points from the photographs in 3-D space. The results of this technique can be used to construct point clouds, orthomosaics, and digital surface models that can be imported into GIS and related software for further study. The accuracy of the reconstructed outcrops, with respect to an absolute framework, is improved with geotagged images or independently gathered ground control points, and the internal accuracy of 3-D reconstructions is sufficient for sub-meter scale measurements. We demonstrate this approach with a case study from central Utah, USA, where UAV-SfM data can help delineate complex features within Jurassic fluvial sandstones.

Underwater Photogrammetry, Coded Target and Plenoptic Technology: a Set of Tools for Monitoring Red Coral in Mediterranean Sea in the Framework of the "perfect" Project

NASA Astrophysics Data System (ADS)

Drap, P.; Royer, J. P.; Nawaf, M. M.; Saccone, M.; Merad, D.; López-Sanz, À.; Ledoux, J. B.; Garrabou, J.

2017-02-01

PErfECT "Photogrammetry, gEnetic, Ecology for red coral ConservaTion" is a project leaded by the Laboratoire des Sciences de lInformation et des Systmes (LSIS - UMR 7296 CNRS) from the Aix-Marseille University (France) in collaboration with the Spanish National Agency for Scientific Research (CSIC, Spain). The main objective of the project is to develop innovative Tools for the conservation of the Mediterranean red coral, Corallium rubrum. PErfECT was funded by the Total Fundation. The adaptation of digital photogrammetric techniques for use in submarine is rapidly increasing in recent years. In fact, these techniques are particularly well suited for use in underwater environments. PErfECT developed different photogrammetry tools to enhance the red coral population surveys based in: (i) automatic orientation on coded quadrats, (ii) use of NPR (Non Photo realistic Rendering) techniques, (iii) the calculation of distances between colonies within local populations and finally (iv) the use of plenoptic approaches in underwater conditions.

Three-dimensional photogrammetry for surgical planning of tissue expansion in hemifacial microsomia.

PubMed

Jayaratne, Yasas S N; Lo, John; Zwahlen, Roger A; Cheung, Lim K

2010-12-01

We aim to illustrate the applications of 3-dimensional (3-D) photogrammetry for surgical planning and longitudinal assessment of the volumetric changes in hemifacial microsomia. A 3-D photogrammetric system was employed for planning soft tissue expansion and transplantation of a vascularized scapular flap for a patient with hemifacial microsomia. The facial deficiency was calculated by superimposing a mirror of the normal side on the preoperative image. Postsurgical volumetric changes were monitored by serial superimposition of 3-D images. A total of 31 cm(3) of tissue expansion was achieved within a period of 4 weeks. A scapular free flap measuring 8 cm × 5 cm was transplanted to augment the facial deficiency. Postsurgical shrinkage of the flap was observed mainly in the first 3 months and it was minimal thereafter. 3-D photogrammetry can be used as a noninvasive objective tool for assessing facial deformity, planning, and postoperative follow-up of surgical correction of facial asymmetry.

From the Road Sign to the Map: 3d Modeling in Support of the Urban and Rural Road Conditions

NASA Astrophysics Data System (ADS)

Palummo, A.

2017-05-01

Unmanned Aerial Vehicles (UAV), commonly known as a drone, and an Unmanned Aircraft Systems (UAS) have been spreading on a massive scale during the last few years, especially for civilian use. And this situation can have significant repercussions on the ways and purposes with which we make photogrammetry nowadays. In this brief article we take into account the italian road signs as a case study on which to apply the new potential of photogrammetry realized with the aid of drones. Our main purpose is to achieve a specific method which allows the calculation of centimeter precision measurements of solids reconstructed for a mapping of (public and private) road signs which require verification or replacement in urban, peri-urban and rural areas. Our hope is that this new approach to photogrammetry may arise opportunities for dialogue with policy makers especially where the usefulness of mapping could also appear predictive with respect to recurrent issues before they become consolidated.

Greenland outlet glacier dynamics from Extreme Ice Survey (EIS) photogrammetry

NASA Astrophysics Data System (ADS)

Hawbecker, P.; Box, J. E.; Balog, J. D.; Ahn, Y.; Benson, R. J.

2010-12-01

Time Lapse cameras fill gaps in our observational capabilities: 1. By providing much higher temporal resolution than offered by conventional airborne or satellite remote sensing. 2. While GPS or auto-theodolite observations can provide higher time resolution data than from photogrammetry, survival of these instruments on the hazardous glacier surface is limited, plus, the maintenance of such systems can be more expensive than the maintenance of a terrestrial photogrammetry installation. 3. Imagery provide a high spatial density of observations across the glacier surface, higher than is realistically available from GPS or other in-situ observations. 4. time lapse cameras provide observational capabilities in Eulerian and Lagrangian frames while GPS or theodolite targets, going along for a ride on the glacier, provide only Lagrangian data. Photogrammetry techniques are applied to a year-plus of images from multiple west Greenland glaciers to determine the glacier front horizontal velocity variations at hourly to seasonal time scales. The presentation includes comparisons between glacier front velocities and: 1. surface melt rates inferred from surface air temperature and solar radiation observations; 2. major calving events identified from camera images; 3. surface and near-surface ocean temperature; 4. land-fast sea ice breakup; 5. tidal variations; 6. supra-glacial melt lake drainage events observed in daily optical satellite imagery; and 7.) GPS data. Extreme Ice Survey (EIS) time lapse camera overlooking the Petermann glacier, installed to image glacier dynamics and to capture the predicted ice "island" detachment.

Uav Borne Low Altitude Photogrammetry System

NASA Astrophysics Data System (ADS)

Lin, Z.; Su, G.; Xie, F.

2012-07-01

In this paper，the aforementioned three major aspects related to the Unmanned Aerial Vehicles (UAV) system for low altitude aerial photogrammetry, i.e., flying platform, imaging sensor system and data processing software, are discussed. First of all, according to the technical requirements about the least cruising speed, the shortest taxiing distance, the level of the flight control and the performance of turbulence flying, the performance and suitability of the available UAV platforms (e.g., fixed wing UAVs, the unmanned helicopters and the unmanned airships) are compared and analyzed. Secondly, considering the restrictions on the load weight of a platform and the resolution pertaining to a sensor, together with the exposure equation and the theory of optical information, the principles of designing self-calibration and self-stabilizing combined wide-angle digital cameras (e.g., double-combined camera and four-combined camera) are placed more emphasis on. Finally, a software named MAP-AT, considering the specialty of UAV platforms and sensors, is developed and introduced. Apart from the common functions of aerial image processing, MAP-AT puts more effort on automatic extraction, automatic checking and artificial aided adding of the tie points for images with big tilt angles. Based on the recommended process for low altitude photogrammetry with UAVs in this paper, more than ten aerial photogrammetry missions have been accomplished, the accuracies of Aerial Triangulation, Digital orthophotos(DOM)and Digital Line Graphs(DLG) of which meet the standard requirement of 1:2000, 1:1000 and 1:500 mapping.

Metopic synostosis: Measuring intracranial volume change following fronto-orbital advancement using three-dimensional photogrammetry.

PubMed

Freudlsperger, Christian; Steinmacher, Sahra; Bächli, Heidi; Somlo, Elek; Hoffmann, Jürgen; Engel, Michael

2015-06-01

There is still disagreement regarding the intracranial volumes of patients with metopic synostosis compared with healthy patients. This study aimed to compare the intracranial volume of children with metopic synostosis before and after surgery to an age- and sex-matched control cohort using three-dimensional (3D) photogrammetry. Eighteen boys with metopic synostosis were operated on using standardized fronto-orbital advancement. Frontal, posterior and total intracranial volumes were measured exactly 1 day pre-operatively and 10 days post-operatively, using 3D photogrammetry. To establish an age- and sex-matched control group, the 3D photogrammetric data of 634 healthy boys between the ages of 3 and 13 months were analyzed. Mean age at surgery was 9 months (SD 1.7). Prior to surgery, boys with metopic synostosis showed significantly reduced frontal and total intracranial volumes compared with the reference group, but similar posterior volumes. After surgery, frontal and total intracranial volumes did not differ statistically from the control group. As children with metopic synostosis showed significantly smaller frontal and total intracranial volumes compared with an age- and sex-matched control group, corrective surgery should aim to achieve volume expansion. Furthermore, 3D photogrammetry provides a valuable alternative to CT scans in the measurement of intracranial volume in children with metopic synostosis, which significantly reduces the amount of radiation exposure to the growing brain. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Impression of multiple implants using photogrammetry: description of technique and case presentation.

PubMed

Peñarrocha-Oltra, David; Agustín-Panadero, Rubén; Bagán, Leticia; Giménez, Beatriz; Peñarrocha, María

2014-07-01

To describe a technique for registering the positions of multiple dental implants using a system based on photogrammetry. A case is presented in which a prosthetic treatment was performed using this technique. Three Euroteknika® dental implants were placed to rehabilitate a 55-year-old male patient with right posterior maxillary edentulism. Three months later, the positions of the implants were registered using a photogrammetry-based stereo-camera (PICcamera®). After processing patient and implant data, special abutments (PICabutment®) were screwed onto each implant. The PICcamera® was then used to capture images of the implant positions, automatically taking 150 images in less than 60 seconds. From this information a file was obtained describing the relative positions - angles and distances - of each implant in vector form. Information regarding the soft tissues was obtained from an alginate impression that was cast in plaster and scanned. A Cr-Co structure was obtained using CAD/CAM, and its passive fit was verified in the patient's mouth using the Sheffield test and the screw resistance test. Twelve months after loading, peri-implant tissues were healthy and no marginal bone loss was observed. The clinical application of this new system using photogrammetry to record the position of multiple dental implants facilitated the rehabilitation of a patient with posterior maxillary edentulism by means of a prosthesis with optimal fit. The prosthetic process was accurate, fast, simple to apply and comfortable for the patient.

Applications of Panoramic Images: from 720° Panorama to Interior 3d Models of Augmented Reality

NASA Astrophysics Data System (ADS)

Lee, I.-C.; Tsai, F.

2015-05-01

A series of panoramic images are usually used to generate a 720° panorama image. Although panoramic images are typically used for establishing tour guiding systems, in this research, we demonstrate the potential of using panoramic images acquired from multiple sites to create not only 720° panorama, but also three-dimensional (3D) point clouds and 3D indoor models. Since 3D modeling is one of the goals of this research, the location of the panoramic sites needed to be carefully planned in order to maintain a robust result for close-range photogrammetry. After the images are acquired, panoramic images are processed into 720° panoramas, and these panoramas which can be used directly as panorama guiding systems or other applications. In addition to these straightforward applications, interior orientation parameters can also be estimated while generating 720° panorama. These parameters are focal length, principle point, and lens radial distortion. The panoramic images can then be processed with closerange photogrammetry procedures to extract the exterior orientation parameters and generate 3D point clouds. In this research, VisaulSFM, a structure from motion software is used to estimate the exterior orientation, and CMVS toolkit is used to generate 3D point clouds. Next, the 3D point clouds are used as references to create building interior models. In this research, Trimble Sketchup was used to build the model, and the 3D point cloud was added to the determining of locations of building objects using plane finding procedure. In the texturing process, the panorama images are used as the data source for creating model textures. This 3D indoor model was used as an Augmented Reality model replacing a guide map or a floor plan commonly used in an on-line touring guide system. The 3D indoor model generating procedure has been utilized in two research projects: a cultural heritage site at Kinmen, and Taipei Main Station pedestrian zone guidance and navigation system. The results presented in this paper demonstrate the potential of using panoramic images to generate 3D point clouds and 3D models. However, it is currently a manual and labor-intensive process. A research is being carried out to Increase the degree of automation of these procedures.

Noninvasive computerized scanning method for the correlation between the facial soft and hard tissues for an integrated three-dimensional anthropometry and cephalometry.

PubMed

Galantucci, Luigi Maria; Percoco, Gianluca; Lavecchia, Fulvio; Di Gioia, Eliana

2013-05-01

The article describes a new methodology to scan and integrate facial soft tissue surface with dental hard tissue models in a three-dimensional (3D) virtual environment, for a novel diagnostic approach.The facial and the dental scans can be acquired using any optical scanning systems: the models are then aligned and integrated to obtain a full virtual navigable representation of the head of the patient. In this article, we report in detail and further implemented a method for integrating 3D digital cast models into a 3D facial image, to visualize the anatomic position of the dentition. This system uses several 3D technologies to scan and digitize, integrating them with traditional dentistry records. The acquisitions were mainly performed using photogrammetric scanners, suitable for clinics or hospitals, able to obtain high mesh resolution and optimal surface texture for the photorealistic rendering of the face. To increase the quality and the resolution of the photogrammetric scanning of the dental elements, the authors propose a new technique to enhance the texture of the dental surface. Three examples of the application of the proposed procedure are reported in this article, using first laser scanning and photogrammetry and then only photogrammetry. Using cheek retractors, it is possible to scan directly a great number of dental elements. The final results are good navigable 3D models that integrate facial soft tissue and dental hard tissues. The method is characterized by the complete absence of ionizing radiation, portability and simplicity, fast acquisition, easy alignment of the 3D models, and wide angle of view of the scanner. This method is completely noninvasive and can be repeated any time the physician needs new clinical records. The 3D virtual model is a precise representation both of the soft and the hard tissue scanned, and it is possible to make any dimensional measure directly in the virtual space, for a full integrated 3D anthropometry and cephalometry. Moreover, the authors propose a method completely based on close-range photogrammetric scanning, able to detect facial and dental surfaces, and reducing the time, the complexity, and the cost of the scanning operations and the numerical elaboration.

Close-range airborne photogrammetry: an effective tool for high-resolution sandy beach morphometric surveys. Examples from embayed beaches in French Guyana.

NASA Astrophysics Data System (ADS)

Brunier, Guillaume; Fleury, Jules; Anthony, Edward; Gardel, Antoine; Dussouillez, Philippe

2015-04-01

Photogrammetric techniques are at a turning point in their history with the development of new algorithms, such as SIFT (Lowe, 1999) for automatic camera alignment and point cloud densification (Furukawa, 2010) integrated in user-friendly end-products. These innovations facilitate the utilization of this technique to study objects with low to mild morphological contrasts at low cost and by non-specialists. It is now possible to produce high-resolution 3D morphometric models, and derived products such as Digital Surface Models (DSM) and Orthophotographs. We conducted three photogrammetric experiments on the embayed beach of Montjoly (4 km long, 100-200 m wide) in Cayenne, French Guyana, in order to quantify morphological changes. The beach is affected by rotation induced by westward migration of mud banks from the Amazon that generate spatio-temporal changes in wave refraction and incident wave angles. The current rotation involves massive erosion of the northern part of the beach (50 m retreat between October 2013 and March 2014) and deposition in the southern sector (50 m advance). We acquired subvertical aerial photographs from a microlight aircraft using a full frame DSLR sensor with a 50 mm lens synchronized with an onboard DGPS, and flew alongshore at low elevation (900 ft). The flight plan included several parallel flight axes with a 50 m interband distance. Meanwhile on the ground, we placed around 30 square targets of 40 cm width georeferenced by RTK-DGPS with centimetre accuracy. These targets served in producing the georeferenced output 3D model. Third, we measured the topography of random points and cross-shore profiles to validate our results and assess the process accuracy. We produced the model and its derived products with user-friendly Agisoft Photoscan© software. We obtained three morphometric models realized in October 2013, March 2014 and October 2014 covering the entire beach. These models were produced at a resolution of 10 cm per pixel and have a mean vertical accuracy less than +/- 5 cm compared to the GPS control points, with a maximum of 20 cm in marginal sectors near vegetation and in the swash zone in low-water conditions. To our knowledge, this is the first time a poorly textured surface composed of sand is reconstructed by photogrammetry, contrast in the studied object being necessary for this method. Our highly accurate photo resolution and pre-processing permitted imaging enough texture to proceed. Morphological features in the upper surf zone such as rip channels, and subaerial features, such as erosion scarps and aeolian forms, clearly appear. The comparison between the DSM validates the estimation of sediment transfers and the rotation process on this beach, unlike traditional beach monitoring with GPS, which involves large uncertainty linked to sparse point acquisition. It can be claimed that photogrammetry is low-cost, user-friendly, and offers new perspectives for non-specialist users in geomorphology and other fields recquiring high-resolution topographic data. It combines the advantages of the reproducibility of GPS topographic surveys and the high density and accuracy of LIDAR, but at very advantageous cost compared to the latter.

Automatic detection of blurred images in UAV image sets

NASA Astrophysics Data System (ADS)

Sieberth, Till; Wackrow, Rene; Chandler, Jim H.

2016-12-01

Unmanned aerial vehicles (UAV) have become an interesting and active research topic for photogrammetry. Current research is based on images acquired by an UAV, which have a high ground resolution and good spectral and radiometrical resolution, due to the low flight altitudes combined with a high resolution camera. UAV image flights are also cost effective and have become attractive for many applications including, change detection in small scale areas. One of the main problems preventing full automation of data processing of UAV imagery is the degradation effect of blur caused by camera movement during image acquisition. This can be caused by the normal flight movement of the UAV as well as strong winds, turbulence or sudden operator inputs. This blur disturbs the visual analysis and interpretation of the data, causes errors and can degrade the accuracy in automatic photogrammetric processing algorithms. The detection and removal of these images is currently achieved manually, which is both time consuming and prone to error, particularly for large image-sets. To increase the quality of data processing an automated process is necessary, which must be both reliable and quick. This paper describes the development of an automatic filtering process, which is based upon the quantification of blur in an image. Images with known blur are processed digitally to determine a quantifiable measure of image blur. The algorithm is required to process UAV images fast and reliably to relieve the operator from detecting blurred images manually. The newly developed method makes it possible to detect blur caused by linear camera displacement and is based on human detection of blur. Humans detect blurred images best by comparing it to other images in order to establish whether an image is blurred or not. The developed algorithm simulates this procedure by creating an image for comparison using image processing. Creating internally a comparable image makes the method independent of additional images. However, the calculated blur value named SIEDS (saturation image edge difference standard-deviation) on its own does not provide an absolute number to judge if an image is blurred or not. To achieve a reliable judgement of image sharpness the SIEDS value has to be compared to other SIEDS values from the same dataset. The speed and reliability of the method was tested using a range of different UAV datasets. Two datasets will be presented in this paper to demonstrate the effectiveness of the algorithm. The algorithm proves to be fast and the returned values are optically correct, making the algorithm applicable for UAV datasets. Additionally, a close range dataset was processed to determine whether the method is also useful for close range applications. The results show that the method is also reliable for close range images, which significantly extends the field of application for the algorithm.

Operational experience in underwater photogrammetry

NASA Astrophysics Data System (ADS)

Leatherdale, John D.; John Turner, D.

Underwater photogrammetry has become established as a cost-effective technique for inspection and maintenance of platforms and pipelines for the offshore oil industry. A commercial service based in Scotland operates in the North Sea, USA, Brazil, West Africa and Australia. 70 mm cameras and flash units are built for the purpose and analytical plotters and computer graphics systems are used for photogrammetric measurement and analysis of damage, corrosion, weld failures and redesign of underwater structures. Users are seeking simple, low-cost systems for photogrammetric analysis which their engineers can use themselves.

Precise deformation measurement of prestressed concrete beam during a strain test using the combination of intersection photogrammetry and micro-network measurement

NASA Astrophysics Data System (ADS)

Urban, Rudolf; Braun, Jaroslav; Štroner, Martin

2015-05-01

The prestressed thin-walled concrete elements enable the bridge a relatively large span. These structures are advantageous in economic and environmental way due to their thickness and lower consumption of materials. The bending moments can be effectively influenced by using the pre-stress. The experiment was done to monitor deformation of the under load. During the experiment the discrete points were monitored. To determine a large number of points, the intersection photogrammetry combined with precise micro-network were chosen. Keywords:

Photogrammetric Techniques for Promotion of Archaeological Heritage: the Archaeological Museum of Parma (italy)

NASA Astrophysics Data System (ADS)

Dall'Asta, E.; Bruno, N.; Bigliardi, G.; Zerbi, A.; Roncella, R.

2016-06-01

In a context rich in history and cultural heritage, such as the Italian one, promotion and enhancement of historical evidences are crucial. The paper describes the case study of the Archaeological Museum of Parma, which, for the main part, conserves evidences found in the roman archaeological site of Veleia (Piacenza, Italy). To enhance the comprehension of the past, the project aims to promote the exhibits through new digital contents, in particular 3D models and AR applications, to improve their usability by the public. Projects like this pose some difficulties especially in data acquisition and restitution due to complexity of the objects and their dimension and position that are not always adequate for an easy survey. Furthermore, in this case, it was necessary to find a solution that takes into account, on one hand, the necessity of a high degree of detail to ensure high metric quality and, on the other hand, the need of producing small files, in order to easy load and consult them on the web or smartphone applications. For all these reasons, close-range photogrammetry was considered the most adequate technique to produce the major part of the models. In this paper, particular attention will be dedicated to the description of the survey campaign and data processing, underlining difficulties and adopted solutions, in order to provide a methodological summary of the actions performed.

Reconstruction of measurable three-dimensional point cloud model based on large-scene archaeological excavation sites

NASA Astrophysics Data System (ADS)

Zhang, Chun-Sen; Zhang, Meng-Meng; Zhang, Wei-Xing

2017-01-01

This paper outlines a low-cost, user-friendly photogrammetric technique with nonmetric cameras to obtain excavation site digital sequence images, based on photogrammetry and computer vision. Digital camera calibration, automatic aerial triangulation, image feature extraction, image sequence matching, and dense digital differential rectification are used, combined with a certain number of global control points of the excavation site, to reconstruct the high precision of measured three-dimensional (3-D) models. Using the acrobatic figurines in the Qin Shi Huang mausoleum excavation as an example, our method solves the problems of little base-to-height ratio, high inclination, unstable altitudes, and significant ground elevation changes affecting image matching. Compared to 3-D laser scanning, the 3-D color point cloud obtained by this method can maintain the same visual result and has advantages of low project cost, simple data processing, and high accuracy. Structure-from-motion (SfM) is often used to reconstruct 3-D models of large scenes and has lower accuracy if it is a reconstructed 3-D model of a small scene at close range. Results indicate that this method quickly achieves 3-D reconstruction of large archaeological sites and produces heritage site distribution of orthophotos providing a scientific basis for accurate location of cultural relics, archaeological excavations, investigation, and site protection planning. This proposed method has a comprehensive application value.

Infrared Cephalic-Vein to Assist Blood Extraction Tasks: Automatic Projection and Recognition

NASA Astrophysics Data System (ADS)

Lagüela, S.; Gesto, M.; Riveiro, B.; González-Aguilera, D.

2017-05-01

Thermal infrared band is not commonly used in photogrammetric and computer vision algorithms, mainly due to the low spatial resolution of this type of imagery. However, this band captures sub-superficial information, increasing the capabilities of visible bands regarding applications. This fact is especially important in biomedicine and biometrics, allowing the geometric characterization of interior organs and pathologies with photogrammetric principles, as well as the automatic identification and labelling using computer vision algorithms. This paper presents advances of close-range photogrammetry and computer vision applied to thermal infrared imagery, with the final application of Augmented Reality in order to widen its application in the biomedical field. In this case, the thermal infrared image of the arm is acquired and simultaneously projected on the arm, together with the identification label of the cephalic-vein. This way, blood analysts are assisted in finding the vein for blood extraction, especially in those cases where the identification by the human eye is a complex task. Vein recognition is performed based on the Gaussian temperature distribution in the area of the vein, while the calibration between projector and thermographic camera is developed through feature extraction and pattern recognition. The method is validated through its application to a set of volunteers, with different ages and genres, in such way that different conditions of body temperature and vein depth are covered for the applicability and reproducibility of the method.

Quantitative facial asymmetry: using three-dimensional photogrammetry to measure baseline facial surface symmetry.

PubMed

Taylor, Helena O; Morrison, Clinton S; Linden, Olivia; Phillips, Benjamin; Chang, Johnny; Byrne, Margaret E; Sullivan, Stephen R; Forrest, Christopher R

2014-01-01

Although symmetry is hailed as a fundamental goal of aesthetic and reconstructive surgery, our tools for measuring this outcome have been limited and subjective. With the advent of three-dimensional photogrammetry, surface geometry can be captured, manipulated, and measured quantitatively. Until now, few normative data existed with regard to facial surface symmetry. Here, we present a method for reproducibly calculating overall facial symmetry and present normative data on 100 subjects. We enrolled 100 volunteers who underwent three-dimensional photogrammetry of their faces in repose. We collected demographic data on age, sex, and race and subjectively scored facial symmetry. We calculated the root mean square deviation (RMSD) between the native and reflected faces, reflecting about a plane of maximum symmetry. We analyzed the interobserver reliability of the subjective assessment of facial asymmetry and the quantitative measurements and compared the subjective and objective values. We also classified areas of greatest asymmetry as localized to the upper, middle, or lower facial thirds. This cluster of normative data was compared with a group of patients with subtle but increasing amounts of facial asymmetry. We imaged 100 subjects by three-dimensional photogrammetry. There was a poor interobserver correlation between subjective assessments of asymmetry (r = 0.56). There was a high interobserver reliability for quantitative measurements of facial symmetry RMSD calculations (r = 0.91-0.95). The mean RMSD for this normative population was found to be 0.80 ± 0.24 mm. Areas of greatest asymmetry were distributed as follows: 10% upper facial third, 49% central facial third, and 41% lower facial third. Precise measurement permitted discrimination of subtle facial asymmetry within this normative group and distinguished norms from patients with subtle facial asymmetry, with placement of RMSDs along an asymmetry ruler. Facial surface symmetry, which is poorly assessed subjectively, can be easily and reproducibly measured using three-dimensional photogrammetry. The RMSD for facial asymmetry of healthy volunteers clusters at approximately 0.80 ± 0.24 mm. Patients with facial asymmetry due to a pathologic process can be differentiated from normative facial asymmetry based on their RMSDs.

In-Vacuum Photogrammetry of a Ten-Meter Square Solar Sail

NASA Technical Reports Server (NTRS)

Pappa, Richard S.; Jones, Thomas W.; Lunsford, Charles B.; Meyer, Christopher G.

2006-01-01

Solar sailing is a promising, future in-space propulsion method that uses the small force of reflecting sunlight to accelerate a large, reflective membrane without expendable propellants. One of two solar sail configurations under development by NASA is a striped net approach by L'Garde, Inc. This design uses four inflatably deployed, lightweight booms supporting a network of thin strings onto which four quadrants of ultrathin aluminized membranes are attached. The NASA Langley Research Center (LaRC) provided both experimental and analytical support to L'Garde for validating the structural characteristics of this unique, ultralightweight spacecraft concept. One of LaRC's responsibilities was to develop and apply photogrammetric methods to measure sail shape. The deployed shape provides important information for validating the accuracy of finite-element modeling techniques. Photogrammetry is the science and art of calculating 3D coordinates of targets or other distinguishing features on structures using images. A minimum of two camera views of each target is required for 3D determination, but having four or more camera views is preferable for improved reliability and accuracy. Using retroreflective circular targets typically provides the highest measurement accuracy and automation. References 3 and 4 provide details of photogrammetry technology, and reference 5 discusses previous experiences with photogrammetry for measuring gossamer spacecraft structures such as solar sails. This paper discusses the experimental techniques used to measure a L Garde 10-m solar sail test in vacuum with photogrammetry. The test was conducted at the NASA-Glenn Space Power Facility (SPF) located at Plum Brook Station in Sandusky, Ohio. The SPF is the largest vacuum chamber in the United States, measuring 30 m in diameter by 37 m in height. High vacuum levels (10(exp -6) torr) can be maintained inside the chamber, and cold environments (-195 C) are possible using variable-geometry cryogenic cold walls. This test used a vacuum level of approximately 1 torr (sufficient for structural static/dynamic characterization) and instead of using the cryogenic cold walls, used local LN2 cold plates underneath each of the four cold-rigidizable solar sail booms instead.

Experimental and Numerical Correlation of Gravity Sag in Solar Sail Quality Membranes

NASA Technical Reports Server (NTRS)

Black, Jonathan T.; Leifer, Jack; DeMoss, Joshua A.; Walker, Eric N.; Belvin, W. Keith

2004-01-01

Solar sails are among the most studied members of the ultra-lightweight and inflatable (Gossamer) space structures family due to their potential to provide propellentless propulsion. They are comprised of ultra-thin membrane panels that, to date, have proven very difficult to experimentally characterize and numerically model due to their reflectivity and flexibility, and the effects of gravity sag and air damping. Numerical models must be correlated with experimental measurements of sub-scale solar sails to verify that the models can be scaled up to represent full-sized solar sails. In this paper, the surface shapes of five horizontally supported 25 micron thick aluminized Kapton membranes were measured to a 1.0 mm resolution using photogrammetry. Several simple numerical models closely match the experimental data, proving the ability of finite element simulations to predict actual behavior of solar sails.

Anthropometric Study of Three-Dimensional Facial Morphology in Malay Adults

PubMed Central

Majawit, Lynnora Patrick; Mohd Razi, Roziana

2016-01-01

Objectives To establish the three-dimensional (3D) facial soft tissue morphology of adult Malaysian subjects of the Malay ethnic group; and to determine the morphological differences between the genders, using a non-invasive stereo-photogrammetry 3D camera. Material and Methods One hundred and nine subjects participated in this research, 54 Malay men and 55 Malay women, aged 20–30 years old with healthy BMI and with no adverse skeletal deviation. Twenty-three facial landmarks were identified on 3D facial images captured using a VECTRA M5-360 Head System (Canfield Scientific Inc, USA). Two angular, 3 ratio and 17 linear measurements were identified using Canfield Mirror imaging software. Intra- and inter-examiner reliability tests were carried out using 10 randomly selected images, analyzed using the intra-class correlation coefficient (ICC). Multivariate analysis of variance (MANOVA) was carried out to investigate morphologic differences between genders. Results ICC scores were generally good for both intra-examiner (range 0.827–0.987) and inter-examiner reliability (range 0.700–0.983) tests. Generally, all facial measurements were larger in men than women, except the facial profile angle which was larger in women. Clinically significant gender dimorphisms existed in biocular width, nose height, nasal bridge length, face height and lower face height values (mean difference > 3mm). Clinical significance was set at 3mm. Conclusion Facial soft tissue morphological values can be gathered efficiently and measured effectively from images captured by a non-invasive stereo-photogrammetry 3D camera. Adult men in Malaysia when compared to women had a wider distance between the eyes, a longer and more prominent nose and a longer face. PMID:27706220

Soft-tissue volumetric changes following monobloc distraction procedure: analysis using digital three-dimensional photogrammetry system (3dMD).

PubMed

Chan, Fuan Chiang; Kawamoto, Henry K; Federico, Christina; Bradley, James P

2013-03-01

We have previously reported that monobloc advancement by distraction osteogenesis resulted in decreased morbidity and greater advancement with less relapse compared with acute monobloc advancement with bone grafting. In this study, we examine the three-dimensional (3D) volumetric soft-tissue changes in monobloc distraction.Patients with syndromic craniosynostosis who underwent monobloc distraction from 2002 to 2010 at University of California-Los Angeles Craniofacial Center were studied (n = 12). We recorded diagnosis, indications for the surgery, and volumetric changes for skeletal and soft-tissue midface structures (preoperative/postoperative [6 weeks]/follow-up [>1 year]). Computed tomography scans and a digital 3D photogrammetry system were used for image analysis.Patients ranged from 6 to 14 years of age (mean, 10.1 years) at the time of the operation (follow-up 2-11 years); mean distraction advancement was 19.4 mm (range, 14-25 mm). There was a mean increase in the 3D volumetric soft-tissue changes: 99.5 ± 4.0 cm(3) (P < 0.05) at 6 weeks and 94.9 ± 3.6 cm(3) (P < 0.05) at 1-year follow-up. When comparing soft-tissue changes at 6 weeks postoperative to 1-year follow-up, there were minimal relapse changes. The overall mean 3D skeletal change was 108.9 ± 4.2 cm. For every 1 cm of skeletal gain, there was 0.78 cm(3) of soft-tissue gain.Monobloc advancement by distraction osteogenesis using internal devices resulted in increased volumetric soft-tissue changes, which remained stable at 1 year. The positive linear correlation between soft-tissue increments and bony advancement can be incorporated during the planning of osteotomies to achieve optimum surgical outcomes with monobloc distraction.

UAV-LiDAR accuracy and comparison to Structure from Motion photogrammetry

NASA Astrophysics Data System (ADS)

Kucharczyk, M.; Hugenholtz, C.; Zou, X.; Nesbit, P. R.; Barchyn, T.

2016-12-01

We compare the spatial accuracy of a UAV-LiDAR system with Structure from Motion (SfM) photogrammetry. UAV-based LiDAR remote sensing potentially offers advantages over SfM photogrammetry in vegetated terrain, particularly with respect to canopy penetration and related measurements of ground surface elevation and vegetation height; however, little quantitative evidence has been presented to date. To address this, we performed a case study at a field site in Alberta, Canada with six different land cover types: short grass, tall grass, short shrubs, tall shrubs, deciduous trees, and coniferous trees. Both UAV datasets were acquired on the same day. The SfM dataset was derived from images acquired by a senseFly eBee fixed-wing UAV equipped with a 16.1 megapixel RGB camera. The UAV-LiDAR system is a proprietary design that consists of a single-rotor helicopter (2-m rotor diameter) equipped with a Riegl VUX-1UAV laser scanner, KVH 1750 inertial measurement unit, and dual NovAtel GNSS receivers. We measured vegetation height from at least 30 samples in each land cover type and acquired check point measurements to determine horizontal and vertical accuracy. Vegetation height was measured manually for grasses and shrubs with a level staff, and with a total station for trees. Coordinates of horizontal and vertical check points were surveyed with real-time kinematic (RTK) GNSS. We followed standard methods for computing horizontal and vertical accuracies based on the 2015 guidelines from the American Society of Photogrammetry and Remote Sensing. Results will be presented at the AGU Fall Meeting.

Applicability of single-camera photogrammetry to determine body dimensions of pinnipeds: Galapagos sea lions as an example.

PubMed

Meise, Kristine; Mueller, Birte; Zein, Beate; Trillmich, Fritz

2014-01-01

Morphological features correlate with many life history traits and are therefore of high interest to behavioral and evolutionary biologists. Photogrammetry provides a useful tool to collect morphological data from species for which measurements are otherwise difficult to obtain. This method reduces disturbance and avoids capture stress. Using the Galapagos sea lion (Zalophus wollebaeki) as a model system, we tested the applicability of single-camera photogrammetry in combination with laser distance measurement to estimate morphological traits which may vary with an animal's body position. We assessed whether linear morphological traits estimated by photogrammetry can be used to estimate body length and mass. We show that accurate estimates of body length (males: ±2.0%, females: ±2.6%) and reliable estimates of body mass are possible (males: ±6.8%, females: 14.5%). Furthermore, we developed correction factors that allow the use of animal photos that diverge somewhat from a flat-out position. The product of estimated body length and girth produced sufficiently reliable estimates of mass to categorize individuals into 10 kg-classes of body mass. Data of individuals repeatedly photographed within one season suggested relatively low measurement errors (body length: 2.9%, body mass: 8.1%). In order to develop accurate sex- and age-specific correction factors, a sufficient number of individuals from both sexes and from all desired age classes have to be captured for baseline measurements. Given proper validation, this method provides an excellent opportunity to collect morphological data for large numbers of individuals with minimal disturbance.

Integration of UAV and ground-based Structure from Motion with Multi-View Stereo photogrammetry and hydrological data to quantify hillslope gully erosion processes in tropical savanna

NASA Astrophysics Data System (ADS)

Koci, J.; Jarihani, B.; Sidle, R. C.; Wilkinson, S. N.; Bartley, R.

2017-12-01

Structure from Motion with Multi-View Stereo (SfM-MVS) photogrammetry provides a cost-effective method of rapidly acquiring high resolution (sub-meter) topographic data, but is rarely used in hydrogeomorphic investigations of gully erosion. This study integrates high resolution topographic and land cover data derived from an unmanned aerial vehicle (UAV) and ground-based SfM-MVS photogrammetry, with rainfall and gully discharge data, to elucidate hydrogeomorphic processes driving hillslope gully erosion. The study is located within a small (13 km2) dry-tropical savanna catchment within the Burdekin River Basin, northeast Australia, which is a major contributor sediments and nutrients to the Great Barrier Reef World Heritage Area. A pre-wet season UAV survey covered an entire hillslope gully system (0.715 km2), and is used to derive topography, ground cover and hydrological flow pathways in the gully contributing area. Ground-based surveys of a single active gully (650 m2) within the broader hillslope are compared between pre- and post-wet season conditions to quantify gully geomorphic change. Rainfall, recorded near to the head of the gully, is related to gully discharge during sporadic storm events. The study provides valuable insights into the relationships among hydrological flow pathways, ground cover, rainfall and runoff, and spatial patterns of gully morphologic change. We demonstrate how UAV and ground-based SfM-MVS photogrammetry can be used to improve hydrogeomorphic process understanding and aid in the modelling and management of hillslope gully systems.

Applicability of Single-Camera Photogrammetry to Determine Body Dimensions of Pinnipeds: Galapagos Sea Lions as an Example

PubMed Central

Meise, Kristine; Mueller, Birte; Zein, Beate; Trillmich, Fritz

2014-01-01

Morphological features correlate with many life history traits and are therefore of high interest to behavioral and evolutionary biologists. Photogrammetry provides a useful tool to collect morphological data from species for which measurements are otherwise difficult to obtain. This method reduces disturbance and avoids capture stress. Using the Galapagos sea lion (Zalophus wollebaeki) as a model system, we tested the applicability of single-camera photogrammetry in combination with laser distance measurement to estimate morphological traits which may vary with an animal’s body position. We assessed whether linear morphological traits estimated by photogrammetry can be used to estimate body length and mass. We show that accurate estimates of body length (males: ±2.0%, females: ±2.6%) and reliable estimates of body mass are possible (males: ±6.8%, females: 14.5%). Furthermore, we developed correction factors that allow the use of animal photos that diverge somewhat from a flat-out position. The product of estimated body length and girth produced sufficiently reliable estimates of mass to categorize individuals into 10 kg-classes of body mass. Data of individuals repeatedly photographed within one season suggested relatively low measurement errors (body length: 2.9%, body mass: 8.1%). In order to develop accurate sex- and age-specific correction factors, a sufficient number of individuals from both sexes and from all desired age classes have to be captured for baseline measurements. Given proper validation, this method provides an excellent opportunity to collect morphological data for large numbers of individuals with minimal disturbance. PMID:24987983

Automatic Detection and Reproduction of Natural Head Position in Stereo-Photogrammetry.

PubMed

Hsung, Tai-Chiu; Lo, John; Li, Tik-Shun; Cheung, Lim-Kwong

2015-01-01

The aim of this study was to develop an automatic orientation calibration and reproduction method for recording the natural head position (NHP) in stereo-photogrammetry (SP). A board was used as the physical reference carrier for true verticals and NHP alignment mirror orientation. Orientation axes were detected and saved from the digital mesh model of the board. They were used for correcting the pitch, roll and yaw angles of the subsequent captures of patients' facial surfaces, which were obtained without any markings or sensors attached onto the patient. We tested the proposed method on two commercial active (3dMD) and passive (DI3D) SP devices. The reliability of the pitch, roll and yaw for the board placement were within ±0.039904°, ±0.081623°, and ±0.062320°; where standard deviations were 0.020234°, 0.045645° and 0.027211° respectively. Orientation-calibrated stereo-photogrammetry is the most accurate method (angulation deviation within ±0.1°) reported for complete NHP recording with insignificant clinical error.

Automatic Detection and Reproduction of Natural Head Position in Stereo-Photogrammetry

PubMed Central

Hsung, Tai-Chiu; Lo, John; Li, Tik-Shun; Cheung, Lim-Kwong

2015-01-01

The aim of this study was to develop an automatic orientation calibration and reproduction method for recording the natural head position (NHP) in stereo-photogrammetry (SP). A board was used as the physical reference carrier for true verticals and NHP alignment mirror orientation. Orientation axes were detected and saved from the digital mesh model of the board. They were used for correcting the pitch, roll and yaw angles of the subsequent captures of patients’ facial surfaces, which were obtained without any markings or sensors attached onto the patient. We tested the proposed method on two commercial active (3dMD) and passive (DI3D) SP devices. The reliability of the pitch, roll and yaw for the board placement were within ±0.039904°, ±0.081623°, and ±0.062320°; where standard deviations were 0.020234°, 0.045645° and 0.027211° respectively. Conclusion: Orientation-calibrated stereo-photogrammetry is the most accurate method (angulation deviation within ±0.1°) reported for complete NHP recording with insignificant clinical error. PMID:26125616

Advancements in Open Geospatial Standards for Photogrammetry and Remote Sensing from Ogc

NASA Astrophysics Data System (ADS)

Percivall, George; Simonis, Ingo

2016-06-01

The necessity of open standards for effective sharing and use of remote sensing continues to receive increasing emphasis in policies of agencies and projects around the world. Coordination on the development of open standards for geospatial information is a vital step to insure that the technical standards are ready to support the policy objectives. The mission of the Open Geospatial Consortium (OGC) is to advance development and use of international standards and supporting services that promote geospatial interoperability. To accomplish this mission, OGC serves as the global forum for the collaboration of geospatial data / solution providers and users. Photogrammetry and remote sensing are sources of the largest and most complex geospatial information. Some of the most mature OGC standards for remote sensing include the Sensor Web Enablement (SWE) standards, the Web Coverage Service (WCS) suite of standards, encodings such as NetCDF, GMLJP2 and GeoPackage, and the soon to be approved Discrete Global Grid Systems (DGGS) standard. In collaboration with ISPRS, OGC working with government, research and industrial organizations continue to advance the state of geospatial standards for full use of photogrammetry and remote sensing.

Photogrammetry and Videogrammetry Methods for Solar Sails and Other Gossamer Structures

NASA Technical Reports Server (NTRS)

Black, Jonathan T.; Pappa, Richard S.

2004-01-01

Ultra-lightweight and inflatable gossamer space structures are designed to be tightly packaged for launch, then deploy or inflate once in space. These properties will allow for in-space construction of very large structures 10 to 1000 meters in size such as solar sails, inflatable antennae, and space solar power stations using a single launch. Solar sails are of particular interest because of their potential for propellantless propulsion. Gossamer structures do, however, have significant complications. Their low mass and high flexibility make them very difficult to test on the ground. The added mass and stiffness of attached measurement devices can significantly alter the static and dynamic properties of the structure. This complication necessitates an alternative approach for characterization. This paper discusses the development and application of photogrammetry and videogrammetry methods for the static and dynamic characterization of gossamer structures, as four specific solar sail applications demonstrate. The applications prove that high-resolution, full-field, non-contact static measurements of solar sails using dot projection photogrammetry are possible as well as full-field, noncontact, dynamic characterization using dot projection videogrammetry.

A New Blondin System for Surveying and Photogrammetry

PubMed Central

Cuesta, Federico; Lopez-Rodriguez, Francisco M.; Esteban, Antonio

2013-01-01

The main objective of the system presented in this paper is to provide surveyors and engineers with a new photogrammetry device that can be easily integrated with surveying total stations and a global navigation satellite system (GNSS) infrastructure at a construction site, taking advantage of their accuracy and overcoming limitations of aerial vehicles with respect to weight, autonomy and skilled operator requirements in aerial photogrammetry. The system moves between two mounting points, in a blondin ropeway configuration, at the construction site, taking pictures and recording the data of the position and the orientation along the cable path. A cascaded extended Kalman filter is used to integrate measurements from the on-board inertial measurement unit (IMU), a GPS and a GNSS. Experimental results taken in a construction site show the system performance, including the validation of the position estimation, with a robotic surveying total station, or the creation of a digital surface model (DSM), using the emergent structure from motion (SfM) techniques and open software. The georeferencing of the DSM is performed based on estimated camera position or using ground control points (GCPs).

Measurements of Tip Vortices from a Full-Scale UH-60A Rotor by Retro- Reflective Background Oriented Schlieren and Stereo Photogrammetry

NASA Technical Reports Server (NTRS)

Schairer, Edward; Kushner, Laura K.; Heineck, James T.

2013-01-01

Positions of vortices shed by a full-scale UH-60A rotor in forward flight were measured during a test in the National Full- Scale Aerodynamics Complex at NASA Ames Research Center. Vortices in a region near the tip of the advancing blade were visualized from two directions by Retro-Reflective Background-Oriented Schlieren (RBOS). Correspondence of points on the vortex in the RBOS images from both cameras was established using epipolar geometry. The object-space coordinates of the vortices were then calculated from the image-plane coordinates using stereo photogrammetry. One vortex from the tip of the blade that had most recently passed was visible in most of the data. The visibility of the vortices was greatest at high thrust and low advance ratios. At these favorable conditions, vortices from the most recent passages of all four blades were detected. The vortex positions were in good agreement with PIV data for a case where PIV measurements were also made. RBOS and photogrammetry provided measurements of the angle at which each vortex passed through the PIV plane.

Matching tire tracks on the head using forensic photogrammetry.

PubMed

Thali, M J; Braun, M; Brüschweiler, W; Dirnhofer, R

2000-09-11

In the field of the documentation of forensics-relevant injuries, from the reconstructive point of view, the forensic, CAD-supported photogrammetry plays an important role; particularly so when a detailed 3-D reconstruction is vital. This is demonstrated with a soft-tissue injury to the face caused by being run over by a car tire. Since the objects (injury and surface of the tire) to be investigated will be evaluated in virtual space, they must be series photographed. These photo sequences are then evaluated with the RolleiMetric multi-image evaluation system. This system measures and calculates the spatial location of points shown in the photo sequences, and creates 3-D data models of the objects. In a 3-D CAD program, the model of the injury is then compared against the model of the possible injury-causing instrument. The validation of the forensic, CAD-supported photogrammetry, as shown by the perfect 3-D match between the tire tread and the facial injury, demonstrates how greatly this 3-D method surpasses the classic 2-D overlay method (one-to-one photography).

Photo Realistic 3d Modeling with Uav: GEDİK Ahmet Pasha Mosque in AFYONKARAHİSAR

NASA Astrophysics Data System (ADS)

Uysal, M.; Toprak, A. S.; Polat, N.

2013-07-01

Many of the cultural heritages in the world have been totally or partly destroyed by natural events and human activities such as earthquake, flood and fire until the present day. Cultural heritages are legacy for us as well; it is also a fiduciary for next generation. To deliver this fiduciary to the future generations, cultural heritages have to be protected and registered. There are different methods for applying this registry but Photogrammetry is the most accurate and rapid method. Photogrammetry enables us to registry cultural heritages and generating 3D photo-realistic models. Nowadays, 3D models are being used in various fields such as education and tourism. In registration of complex and high construction by Photogrammetry, there are some problems in data acquisition and processing. Especially for high construction's photographs, some additional equipment is required such as balloon and lifter. In recent years The Unmanned Aerial Vehicles (UAV) are commonly started to be used in different fields for different goals. In Photogrammetry, The UAVs are being used for particularly data acquisition. It is not always easy to capture data due to the situation of historical places and their neighbourhood. The use of UAVs for documentation of cultural heritage will make an important contribution. The main goals of this study are to survey cultural heritages by Photogrammetry and to investigate the potential of UAVs in 3D modelling. In this purpose we surveyed Gedik Ahmet Pasha Mosque photogrammetricly by UAV and will produce photorealistic 3D model. Gedik Ahmet Pasha, The Grand Vizier of Fatih Sultan Mehmet, has been in Afyonkarahisar during the campaign to Karaman between the years of 1472-1473. He wanted Architect Ayaz Agha to build a complex of Bathhouse, Mosque and a Madrasah here, Afyon, due to admiration of this city. Gedik Ahmet Pasha Mosque is in the centre of this complex. Gedik Ahmet Pasha Mosque is popularly known as Imaret Mosque among the people of Afyon. Gedik Ahmet Pasha Complex is a foundation. For this reason all its expenses are recorded. Furthermore renovations of all buildings in this complex are placed on them with a inscription. According to records and inscriptions The Imaret Mosque has been restored several times. The two significant of these restorations were made after the earthquakes in 1668 and 1792. Lastly, after the renewing lead plating of domes in 1969, the Mosque has gotten its current final situation. The dimensions of Mosque are 29.20 x 35.40 in meter and it has built by a plan of inverse capital (T). There are two domes covering the main worship and it is one of the most important examples of Ottoman architecture with three of dome both side in direction of east to west. At the north side of the Mosque, there is a place for last congregations with five domes. Minaret is at the north-east side of the mosque. It has got one balcony (surrounding the minaret) and has been structured by cut stone with a shape of fluting. It has been covered by dark blue tile between these flutings. The main gate of mosque is made of pen inlaid marble. It is aimed to survey Gedik Ahmet Pasha Mosque photogrammetricly and to model it in 3D photo-realistic. In this study, South NTS-352 Total Station is used to constitute a closed polygon with 8 point. We used 350 ground control point in the field study. It is made levelling to measure elevation of polygon points. For photographs, we used Canon A 180 camera and UAV. Photomodeler software is used to process both camera's and UAV's photographs independently. The facades of mosque are derived and all 3D models of Mosque were merged. This merged model is covered with high resolution photographs for obtaining 3D photo-realistic models of Gedik Ahmet Pasha Mosque.

Application of UAV-SfM photogrammetry and aerial lidar to a disastrous flood: repeated topographic measurement of a newly formed crevasse splay of the Kinu River, central Japan

NASA Astrophysics Data System (ADS)

Izumida, Atsuto; Uchiyama, Shoichiro; Sugai, Toshihiko

2017-09-01

Geomorphic impacts of a disastrous crevasse splay that formed in September 2015 and its post-formation modifications were quantitatively documented by using repeated, high-definition digital surface models (DSMs) of an inhabited and cultivated floodplain of the Kinu River, central Japan. The DSMs were based on pre-flood (resolution: 2 m) and post-flood (resolution: 1 m) aerial light detection and ranging (lidar) data from January 2007 and September 2015, respectively, and on structure-from-motion (SfM) photogrammetry data (resolution: 3.84 cm) derived from aerial photos taken by an unmanned aerial vehicle (UAV) in December 2015. After elimination of systematic errors among the DSMs and down-sampling of the SfM-derived DSM, elevation changes on the order of 10-1 m - including not only topography but also growth of vegetation, vanishing of flood waters, and restoration and repair works - were detected. Comparison of the DSMs showed that the volume eroded by the flood was more than twice the deposited volume in the area within 300-500 m of the breached artificial levee, where the topography was significantly affected. The results suggest that DSMs based on a combination of UAV-SfM and lidar data can be used to quantify, rapidly and in rich detail, topographic changes on floodplains caused by floods.

From Geometry to Diagnosis: Experiences of Geomatics in Structural Engineering

NASA Astrophysics Data System (ADS)

Riveiro, B.; Arias, P.; Armesto, J.; Caamaño, J. C.; Solla, M.

2012-07-01

Terrestrial photogrammetry and laser scanning are technologies that have been successfully used for metric surveying and 3D modelling in many different fields (archaeological and architectural documentation, industrial retrofitting, mining, structural monitoring, road surveying, etc.). In the case of structural applications, these techniques have been successfully applied to 3D modelling and sometimes monitoring; but they have not been sufficiently implemented to date, as routine tools in infrastructure management systems, in terms of automation of data processing and integration in the condition assessment procedures. In this context, this paper presents a series of experiences in the usage of terrestrial photogrammetry and laser scanning in the context of dimensional and structural evaluation of structures. These experiences are particularly focused on historical masonry structures, but modern prestressed concrete bridges are also investigated. The development of methodological procedures for data collection, and data integration in some cases, is tackled for each particular structure (with access limitations, geometrical configuration, range of measurement, etc.). The accurate geometrical information provided by both terrestrial techniques motivates the implementation of such results in the complex, and sometimes slightly approximated, geometric scene that is frequently used in structural analysis. In this sense, quantitative evaluating of the influence of real and accurate geometry in structural analysis results must be carried out. As main result in this paper, a series of experiences based on the usage of photogrammetric and laser scanning to structural engineering are presented.

BLM Unmanned Aircraft Systems (UAS) Resource Management Operations

NASA Astrophysics Data System (ADS)

Hatfield, M. C.; Breen, A. L.; Thurau, R.

2016-12-01

The Department of the Interior Bureau of Land Management is funding research at the University of Alaska Fairbanks to study Unmanned Aircraft Systems (UAS) Resource Management Operations. In August 2015, the team conducted flight research at UAF's Toolik Field Station (TFS). The purpose was to determine the most efficient use of small UAS to collect low-altitude airborne digital stereo images, process the stereo imagery into close-range photogrammetry products, and integrate derived imagery products into the BLM's National Assessment, Inventory and Monitoring (AIM) Strategy. The AIM Strategy assists managers in answering questions of land resources at all organizational levels and develop management policy at regional and national levels. In Alaska, the BLM began to implement its AIM strategy in the National Petroleum Reserve-Alaska (NPR-A) in 2012. The primary goals of AIM-monitoring at the NPR-A are to implement an ecological baseline to monitor ecological trends, and to develop a monitoring network to understand the efficacy of management decisions. The long-term AIM strategy also complements other ongoing NPR-A monitoring processes, collects multi-use and multi-temporal data, and supports understanding of ecosystem management strategies in order to implement defensible natural resource management policy. The campaign measured vegetation types found in the NPR-A, using UAF's TFS location as a convenient proxy. The vehicle selected was the ACUASI Ptarmigan, a small hexacopter (based on DJI S800 airframe and 3DR autopilot) capable of carrying a 1.5 kg payload for 15 min for close-range environmental monitoring missions. The payload was a stereo camera system consisting of Sony NEX7's with various lens configurations (16/20/24/35 mm). A total of 77 flights were conducted over a 4 ½ day period, with 1.5 TB of data collected. Mission variables included camera height, UAS speed, transect overlaps, and camera lenses/settings. Invaluable knowledge was gained as to limitations and opportunities for field deployment of UAS relative to local conditions and vegetation type. Future efforts will focus of refining data analysis techniques and further optimizing UAS/sensor combinations and flight profiles.

Airborne laser topographic mapping results from initial joint NASA/US Army Corps of Engineers experiment

NASA Technical Reports Server (NTRS)

Krabill, W. B.; Collins, J. G.; Swift, R. N.; Butler, M. L.

1980-01-01

Initial results from a series of joint NASA/US Army Corps of Engineers experiments are presented. The NASA Airborne Oceanographic Lidar (AOL) was exercised over various terrain conditions, collecting both profile and scan data from which river basin cross sections are extracted. Comparisons of the laser data with both photogrammetry and ground surveys are made, with 12 to 27 cm agreement observed over open ground. Foliage penetration tests, utilizing the unique time-waveform sampling capability of the AOL, indicate 50 cm agreement with photogrammetry (known to have difficulty in foliage covered terrain).

Evaluation and Development of E-Learning Tools and Methods in Digital Photogrammetry and Remote Sensing for Non Experts from Academia and Industry

NASA Astrophysics Data System (ADS)

Gülch, E.; Al-Ghorani, N.; Quedenfeldt, B.; Braun, J.

2012-07-01

There does already exist a wide variety of tutorials and on-line courses on Photogrammetry and Remote Sensing very often used in academia. Many of them are still rather static and tedious or target high-knowledge learners. E-learning is, however, increasingly applied by many organizations and companies for life-long learning (like e.g. the EduServ courses of EuroSDR), but also for training of resellers and in order to save the expenses and time of travelling. A new issue of this project when taking into account the ethnic mentality in some countries like Saudi Arabia where it is impossible to mix the females and males at any institution type or for instance to teach ladies by a male teacher face to face, many academic workshops have been done separately twice by foreign organizations to adapt this situation. This paper will focus on these issues and present experiences gathered from a Master Thesis on "E-learning in Digital Photogrammetry and Remote Sensing for Non Experts using Moodle" at HFT Stuttgart in co-operation with a software vendor and a reseller and experiences from a current European Tempus IV project GIDEC (Geographic information technology for sustainable development in Eastern neighouring countries). The aim of this research is to provide an overview on available methods and tools and classify and judge their feasibility for the above mentioned scenarios. A more detailed description is given on the development of e-learning applications for Digital Photogrammetry and Remote Sensing using the open source package Moodle as platform. A first item covers the experiences from setting up and handling of Moodle for non-experts. The major emphasis is then on developing and analyzing some few case studies for lectures, exercises, and software training in the fields of Digital Photogrammetry and Remote Sensing. Feedback from students and company staff will be evaluated and incorporated in an improved design and sample implementation. A further focus is on free software and tools to allow an easy integration of dedicated methods as audio and video flashes, quizzes for self evaluation, dynamic training, web-conference, etc. into the e-learning platform. The overall objective is to evaluate on how far it is currently possibly to allow the non-experts from academic and non academic sectors to get the initial experience and knowledge in Digital Photogrammetry and Remote Sensing in a modern, flexible and economic way. The time and the skills required for developing web-based materials will thus be investigated in more detail. Additionally, the quality of the developed e-learning application will be assessed based on a list of quality criteria developed.

Quantification of skeletal fraction volume of a soil pit by means of photogrammetry

NASA Astrophysics Data System (ADS)

Baruck, Jasmin; Zieher, Thomas; Bremer, Magnus; Rutzinger, Martin; Geitner, Clemens

2015-04-01

The grain size distribution of a soil is a key parameter determining soil water behaviour, soil fertility and land use potential. It plays an important role in soil classification and allows drawing conclusions on landscape development as well as soil formation processes. However, fine soil material (i.e. particle diameter ≤2 mm) is usually documented more thoroughly than the skeletal fraction (i.e. particle diameter >2 mm). While fine soil material is commonly analysed in the laboratory in order to determine the soil type, the skeletal fraction is typically estimated in the field at the profile. For a more precise determination of the skeletal fraction other methods can be applied and combined. These methods can be volume-related (sampling rings, percussion coring tubes) or non-volume-related (sieve of spade excavation). In this study we present a framework for the quantification of skeletal fraction volumes of a soil pit by means of photogrammetry. As a first step 3D point clouds of both soil pit and skeletal grains were generated. Therefore all skeletal grains of the pit were spread out onto a plane, clean plastic sheet in the field and numerous digital photos were taken using a reflex camera. With the help of the open source tool VisualSFM (structure from motion) two scaled 3D point clouds were derived. As a second step the skeletal fraction point cloud was segmented by radiometric attributes in order to determine volumes of single skeletal grains. The comparison of the total skeletal fraction volume with the volume of the pit (closed by spline interpolation) yields an estimate of the volumetric proportion of skeletal grains. The presented framework therefore provides an objective reference value of skeletal fraction for the support of qualitative field records.

Chest diameter ratios for detecting static hyperinflation in children using photogrammetry.

PubMed

Ricieri, Denise da V; Rosário, Nelson A; Costa, Jecilene R

2008-01-01

To develop a photogrammetric method capable of identifying increases in anteroposterior chest diameters suggestive of pulmonary hyperinflation, and to test it with both asthmatic and asthma-free children. Two distinct study designs were used to achieve these two objectives. The first was a descriptive analysis of diameters measured at the height of the axilla and of the xiphoid on digital images of 56 children aged 8 to 12 years photographed in the orthostatic position. The second was a case-control study of (a) 19 asthmatic children in treatment for at least 12 months; and (b) 37 children free from asthma with no prior history of complaints of respiratory/allergic disease. Diameters were measured on images of the front and left side views using CorelDRAW, and the ratio between the front and side diameters was calculated for the axillary and xiphoid measurements, providing the diameter ratios. Diameter ratios close to or greater than 1 represent geometry tending towards a cylindrical shape, typical of hyperinflation on radiographs. Analysis with the t test for independent samples revealed a mean diameter ratio at the sternum that was significantly greater in the group of asthmatic children (p < 0.01) than the mean for the whole sample and also than the mean for the children without asthma. Despite the existence of disagreement on the best instruments, methods and times for identifying hyperinflation, results indicate that a system using diameter ratios obtained by photogrammetry is a promising tool for the identification of a kinesiopathological manifestation that is known to determine air entrapment in asthma patients. Research that combines clinical data with longitudinal intrapatient follow-up will be necessary to establish the strength of the evidence found in this study.

Using digital photogrammetry to constrain the segmentation of Paleocene volcanic marker horizons within the Nuussuaq basin

NASA Astrophysics Data System (ADS)

Vest Sørensen, Erik; Pedersen, Asger Ken

2017-04-01

Digital photogrammetry is used to map important volcanic marker horizons within the Nuussuaq Basin, West Greenland. We use a combination of oblique stereo images acquired from helicopter using handheld cameras and traditional aerial photographs. The oblique imagery consists of scanned stereo photographs acquired with analogue cameras in the 90´ties and newer digital images acquired with high resolution digital consumer cameras. Photogrammetric software packages SOCET SET and 3D Stereo Blend are used for controlling the seamless movement between stereo-models at different scales and viewing angles and the mapping is done stereoscopically using 3d monitors and the human stereopsis. The approach allows us to map in three dimensions three characteristic marker horizons (Tunoqqu, Kûgánguaq and Qordlortorssuaq Members) within the picritic Vaigat Formation. They formed toward the end of the same volcanic episode and are believed to be closely related in time. They formed an approximately coherent sub-horizontal surface, the Tunoqqu Surface that at the time of formation covered more than 3100 km2 on Disko and Nuussuaq. Our mapping shows that the Tunoqqu Surface is now segmented into areas of different elevation and structural trend as a result of later tectonic deformation. This is most notable on Nuussuaq where the western part is elevated and in parts highly faulted. In western Nuussuaq the surface has been uplifted and faulted so that it now forms an asymmetric anticline. The flanks of the anticline are coincident with two N-S oriented pre-Tunoqqu extensional faults. The deformation of the Tunoqqu surface could be explained by inversion of older extensional faults due to an overall E-W directed compressive regime in the late Paleocene.

High Resolution Insights into Snow Distribution Provided by Drone Photogrammetry

NASA Astrophysics Data System (ADS)

Redpath, T.; Sirguey, P. J.; Cullen, N. J.; Fitzsimons, S.

2017-12-01

Dynamic in time and space, New Zealand's seasonal snow is largely confined to remote alpine areas, complicating ongoing in situ measurement and characterisation. Improved understanding and modeling of the seasonal snowpack requires fine scale resolution of snow distribution and spatial variability. The potential of remotely piloted aircraft system (RPAS) photogrammetry to resolve spatial and temporal variability of snow depth and water equivalent in a New Zealand alpine catchment is assessed in the Pisa Range, Central Otago. This approach yielded orthophotomosaics and digital surface models (DSM) at 0.05 and 0.15 m spatial resolution, respectively. An autumn reference DSM allowed mapping of winter (02/08/2016) and spring (10/09/2016) snow depth at 0.15 m spatial resolution, via DSM differencing. The consistency and accuracy of the RPAS-derived surface was assessed by comparison of snow-free regions of the spring and autumn DSMs, while accuracy of RPAS retrieved snow depth was assessed with 86 in situ snow probe measurements. Results show a mean vertical residual of 0.024 m between DSMs acquired in autumn and spring. This residual approximated a Laplace distribution, reflecting the influence of large outliers on the small overall bias. Propagation of errors associated with successive DSMs saw snow depth mapped with an accuracy of ± 0.09 m (95% c.l.). Comparing RPAS and in situ snow depth measurements revealed the influence of geo-location uncertainty and interactions between vegetation and the snowpack on snow depth uncertainty and bias. Semi-variogram analysis revealed that the RPAS outperformed systematic in situ measurements in resolving fine scale spatial variability. Despite limitations accompanying RPAS photogrammetry, this study demonstrates a repeatable means of accurately mapping snow depth for an entire, yet relatively small, hydrological basin ( 0.5 km2), at high resolution. Resolving snowpack features associated with re-distribution and preferential accumulation and ablation, snow depth maps provide geostatistically robust insights into seasonal snow processes, with unprecedented detail. Such data may enhance understanding of physical processes controlling spatial and temporal distribution of seasonal snow, and their relative importance at varying spatial and temporal scales.

Two-dimensional digital photography for child body posture evaluation: standardized technique, reliable parameters and normative data for age 7-10 years.

PubMed

Stolinski, L; Kozinoga, M; Czaprowski, D; Tyrakowski, M; Cerny, P; Suzuki, N; Kotwicki, T

2017-01-01

Digital photogrammetry provides measurements of body angles or distances which allow for quantitative posture assessment with or without the use of external markers. It is becoming an increasingly popular tool for the assessment of the musculoskeletal system. The aim of this paper is to present a structured method for the analysis of posture and its changes using a standardized digital photography technique. The purpose of the study was twofold. The first one comprised 91 children (44 girls and 47 boys) aged 7-10 (8.2 ± 1.0), i.e., students of primary school, and its aim was to develop the photographic method, choose the quantitative parameters, and determine the intraobserver reliability (repeatability) along with the interobserver reliability (reproducibility) measurements in sagittal plane using digital photography, as well as to compare the Rippstein plurimeter and digital photography measurements. The second one involved 7782 children (3804 girls, 3978 boys) aged 7-10 (8.4 ± 0.5), who underwent digital photography postural screening. The methods consisted in measuring and calculating selected parameters, establishing the normal ranges of photographic parameters, presenting percentile charts, as well as noticing common pitfalls and possible sources of errors in digital photography. A standardized procedure for the photographic evaluation of child body posture was presented. The photographic measurements revealed very good intra- and inter-rater reliability regarding the five sagittal parameters and good reliability performed against Rippstein plurimeter measurements. The parameters displayed insignificant variability over time. Normative data were calculated based on photographic assessment, while the percentile charts were provided to serve as reference values. The technical errors observed during photogrammetry are carefully discussed in this article. Technical developments are allowed for the regular use of digital photogrammetry in body posture assessment. Specific child positioning (described above) enables us to avoid incidentally modified posture. Image registration is simple, quick, harmless, and cost-effective. The semi-automatic image analysis, together with the normal values and percentile charts, makes the technique reliable in terms of child's posture documentation and corrective therapy effects' monitoring.

Application of photogrammetry for analysis of occlusal contacts.

PubMed

Shigeta, Yuko; Hirabayashi, Rio; Ikawa, Tomoko; Kihara, Takuya; Ando, Eriko; Hirai, Shinya; Fukushima, Shunji; Ogawa, Takumi

2013-04-01

The conventional 2D-analysis methods for occlusal contacts provided limited information on tooth morphology. This present study aims to detect 3D positional information of occlusal contacts from 2D-photos via photogrammetry. We propose an image processing solution for analysis of occlusal contacts and facets via the black silicone method and a photogrammetric technique. The occlusal facets were reconstructed from a 2D-photograph data-set of inter-occlusal records into a 3D image via photogrammetry. The configuration of the occlusal surface was reproduced with polygons. In addition, the textures of the occlusal contacts were mapped to each polygon. DIFFERENCE FROM CONVENTIONAL METHODS: Constructing occlusal facets with 3D polygons from 2D-photos with photogrammetry was a defining characteristic of this image processing technique. It allowed us to better observe findings of the black silicone method. Compared with conventional 3D analysis using a 3D scanner, our 3D models did not reproduce the detail of the anatomical configuration. However, by merging the findings of the inter-occlusal record, the deformation of mandible and the displacement of periodontal ligaments under occlusal force were reflected in our model. EFFECT OR PERFORMANCE: Through the use of polygons in the conversion of 2D images to 3D images, we were able to define the relation between the location and direction of the occlusal contacts and facets, which was difficult to detect via conventional methods. Through our method of making a 3D polygon model, the findings of inter-occlusal records which reflected the jaw/teeth behavior under occlusal force could be observed 3-dimensionally. Copyright © 2012 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Plot-scale soil loss estimation with laser scanning and photogrammetry methods

NASA Astrophysics Data System (ADS)

Szabó, Boglárka; Szabó, Judit; Jakab, Gergely; Centeri, Csaba; Szalai, Zoltán; Somogyi, Árpád; Barsi, Árpád

2017-04-01

Structure from Motion (SfM) is an automatic feature-matching algorithm, which nowadays is widely used tool in photogrammetry for geoscience applications. SfM method and parallel terrestrial laser scanning measurements are widespread and they can be well accomplished for quantitative soil erosion measurements as well. Therefore, our main scope was soil erosion characterization quantitatively and qualitatively, 3D visualization and morphological characterization of soil-erosion-dynamics. During the rainfall simulation, the surface had been measured and compared before and after the rainfall event by photogrammetry (SfM - Structure from Motion) and laser scanning (TLS - Terrestrial Laser Scanning) methods. The validation of the given results had been done by the caught runoff and the measured soil-loss value. During the laboratory experiment, the applied rainfall had 40 mm/h rainfall intensity. The size of the plot was 0.5 m2. The laser scanning had been implemented with Faro Focus 3D 120 S type equipment, while the SfM shooting had been carried out by 2 piece SJCAM SJ4000+ type, 12 MP resolution and 4K action cams. The photo-reconstruction had been made with Agisoft Photoscan software, while evaluation of the resulted point-cloud from laser scanning and photogrammetry had been implemented partly in CloudCompare and partly in ArcGIS. The resulted models and the calculated surface changes didn't prove to be suitable for estimating soil-loss, only for the detection of changes in the vertical surface. The laser scanning resulted a quite precise surface model, while the SfM method is affected by errors at the surface model due to other factors. The method needs more adequate technical laboratory preparation.

Bridging scales from satellite to grains: Structural mapping aided by tablet and photogrammetry

NASA Astrophysics Data System (ADS)

Hawemann, Friedrich; Mancktelow, Neil; Pennacchioni, Giorgio; Wex, Sebastian; Camacho, Alfredo

2016-04-01

Bridging scales from satellite to grains: Structural mapping aided by tablet and photogrammetry A fundamental problem in small-scale mapping is linking outcrop observations to the large scale deformation pattern. The evolution of handheld devices such as tablets with integrated GPS and the availability of airborne imagery allows a precise localization of outcrops. Detailed structural geometries can be analyzed through ortho-rectified photo mosaics generated by photogrammetry software. In this study, we use a cheap standard Samsung-tablet (< 300 Euro) to map individual, up to 60 m long shear zones with the tracking option offered by the program Locus Map. Even though GPS accuracy is about 3 m, the relative error from one point to another during tracking is on the order of only about 1 dm. Parts of the shear zone with excellent outcrop are photographed with a standard camera with a relatively wide angle in a mosaic array. An area of about 30 sqm needs about 50 photographs with enough overlap to be used for photogrammetry. The software PhotoScan from Agisoft matches the photographs in a fully automated manner, calculates a 3D model of the outcrop, and has the option to project this as an orthophoto onto a flat surface. This allows original orientations of grain-scale structures to be recorded over areas on a scale up to tens to hundreds of metres. The photo mosaics can then be georeferenced with the aid of the GPS-tracks of the shear zones and included in a GIS. This provides a cheap recording of the structures in high detail. The great advantages over mapping with UAVs (drones) is the resolution (<1mm to >1cm), the independence from weather and energy source, and the low cost.

Photogrammetry and altimetry. Part A: Apollo 16 laser altimeter

NASA Technical Reports Server (NTRS)

Wollenhaupt, W. R.; Sjogren, W. L.

1972-01-01

The laser altimeter measures precise altitudes of the command and service module above the lunar surface and can function either with the metric (mapping) camera or independently. In the camera mode, the laser altimeter ranges at each exposure time, which varies between 20 and 28 sec (i.e., 30 to 43 km on the lunar surface). In the independent mode, the laser altimeter ranges every 20 sec. These altitude data and the spacecraft attitudes that are derived from simultaneous stellar photography are used to constrain the photogrammetric reduction of the lunar surface photographs when cartographic products are generated. In addition, the altimeter measurements alone provide broad-scale topographic relief around the entire circumference of the moon. These data are useful in investigating the selenodetic figure of the moon and may provide information regarding gravitational anomalies on the lunar far side.

Positioning sensor by combining optical projection and photogrammetry

NASA Astrophysics Data System (ADS)

Zheng, Benrui

Six spatial parameters, (x, y, z) for translation, and pitch, roll, and yaw for rotation, are used to describe the 3-dimensional position and orientation of a rigid body---the 6 degrees of freedom (DOF). The ability to measure these parameters is required in a diverse range of applications including machine tool metrology, robot calibration, motion control, motion analysis, and reconstructive surgery. However, there are limitations associated with the currently available measurement systems. Shortcomings include some of the following: short dynamic range, limited accuracy, line of sight restrictions, and capital cost. The objective of this dissertation was to develop a new metrology system that overcomes line of sight restrictions, reduces system costs, allows large dynamic range and has the potential to provide high measurement accuracy. The new metrology system proposed in this dissertation is based on a combination of photogrammetry and optical pattern projection. This system has the potential to enable real-time measurement of a small lightweight module's location. The module generates an optical pattern that is observable on the surrounding walls, and photogrammetry is used to measure the absolute coordinates of features in the projected optical pattern with respect to a defined global coordinate system. By combining these absolute coordinates with the known angular information of the optical projection beams, a minimization algorithm can be used to extract the absolute coordinates and angular orientation of the module itself. The feasibility of the proposed metrology system was first proved through preliminary experimental tests. By using a module with a 7x7 dot matrix pattern, experimental agreement of 1 to 5 parts in 103 was obtained by translating the module over 0.9 m and by rotating it through 60°. The proposed metrology system was modeled through numerical simulations and factors affecting the uncertainty of the measurement were investigated. The simulation results demonstrate that optimum design of the projected pattern gives a lower associated measurement uncertainty than is possible by direct photogrammetric measurement with traditional tie points alone. Based on the simulation results, a few improvements have been made to the proposed metrology systems. These improvements include using a module with larger full view angle and larger number of dots, performing angle calibration for the module, using a virtual camera approach to determine the module location and employing multiple coordinates system for large range rotation measurement. With the new proposed virtual camera approach, experimental agreement at the level of 3 parts in 104 was observed for the one dimension translation test. The virtual camera approach is faster than the algorithm and an additional minimization analysis is no longer needed. In addition, the virtual camera approach offers an additional benefit that it is no longer necessary to identify all dots in the pattern and so is more amenable to use in realistic and usually complicated environments. A preliminary rotation test over 120° was conducted by tying three coordinate systems together. It was observed that the absolute values of the angle differences between the measured angle and the encoder reading are smaller than 0.23° for all measurements. It is found that this proposed metrology system has the ability to measure larger angle range (up to 360°) by using multiple coordinate systems. The uncertainty analysis of the proposed system was performed through Monte Carlo simulation and it was demonstrated that the experimental results are consistent with the analysis.

Integration and comparison of different acquisition techniques for landslide monitoring: Cancia landslide case study

NASA Astrophysics Data System (ADS)

Masiero, Andrea; Fissore, Francesca; Degetto, Massimo; Piermattei, Livia; Guarnieri, Alberto; Mezzomo, Rizieri; Gregoretti, Carlo; Piragnolo, Marco; Pirotti, Francesco; Vettore, Antonio

2017-04-01

Terrain instability, landslides and other phenomena mostly caused by hydrogeological risk, often cause damages to human infrastructures, roads and other transport lines: given the recent developments in surveying, electronics and mobile instrumentation, the quest for automated or semi-automated early warning systems is continuously increasing in order to provide reliable technological solutions to reduce risks for both human lives and human building and infrastructures. This work deals with the monitoring a specific area of interest, a landslide located in Cancia (Belluno, Italy). This case study is characterized by the presence of several roads close to the landslide area: in particular, one of them intersects with the landslide. The closeness between landslide and human used areas (e.g. roads) motivate the interest of public authorities in order to reduce risks related to the landslide. To this aim, "Provincia di Belluno, Servizio Difesa del Suolo" actively contributed to this work by providing aerial imagery data of the region of interest. Accessing a reliable reconstruction of certain landslides can be complex due to the difficulty for humans to reach certain areas: often only part of the area of interest can be acquired with highly accurate ground surveying (e.g. terrestrial laser scanning (TLS)), whereas other methods should be considered in order to obtain estimates of the remaining parts of the landslide. Recently, the spread of low cost drones is leading to a growing interest in the choice of unmanned aerial vehicles (UAVs) to acquire aerial imagery, hence enabling low cost photogrammetric reconstruction of the area. Despite being an attractive solution because of the clear convenience in terms of cost and acquisition time, its accuracy has typically not reached that of TLS surveying so far. This paper considers the possibility of comparing and integrating different acquisition techniques (TLS, aerial and close-range photogrammetry) in order to reach the best reconstruction accuracy, wherever is possible, and investigates the possibility of enabling the development of appropriate warning systems based on measurements provided by the above mentioned acquisition approaches (in particular, low cost reconstruction systems are considered in order to deal with the quick detection of risky conditions).

Model Deformation and Optical Angle of Attack Measurement System in the NASA Ames Unitary Plan Wind Tunnel

NASA Technical Reports Server (NTRS)

Kushner, Laura K.; Drain, Bethany A.; Schairer, Edward T.; Heineck, James T.; Bell, James H.

2017-01-01

Both AoA and MDM measurements can be made using an optical system that relies on photogrammetry. Optical measurements are being requested by customers in wind tunnels with increasing frequency due to their non-intrusive nature and recent hardware and software advances that allow measurements to become near real time. The NASA Ames Research Center Unitary Plan Wind Tunnel is currently developing a system based on photogrammetry to measure model deformation and model angle of attack. This paper describes the new system, its development, its use on recent tests and plans to further develop the system.

D Representation of the 19TH Century Balkan Architecture Using Scaled Museum-Maquette and Photogrammetry Methods

NASA Astrophysics Data System (ADS)

Georgiou, E.; Karachaliou, E.; Stylianidis, E.

2017-08-01

Characteristic example of the Balkan architecture of the 19th century, consists the "Tower house" which is found in the region of Epirus and Western Macedonia, Greece. Nowadays, the only information about these heritage buildings could be abstracted by the architectural designs on hand and the model - Tower that is being displayed in the Folklore Museum of the Municipality of Kozani, Greece, as a maquette. The current work generates a scaled 3D digital model of the "Tower house", by using photogrammetry techniques applied on the model-maquette that is being displayed in the Museum exhibits.

Method for Stereo Mapping Based on Objectarx and Pipeline Technology

NASA Astrophysics Data System (ADS)

Liu, F.; Chen, T.; Lin, Z.; Yang, Y.

2012-07-01

Stereo mapping is an important way to acquire 4D production. Based on the development of the stereo mapping and the characteristics of ObjectARX and pipeline technology, a new stereo mapping scheme which can realize the interaction between the AutoCAD and digital photogrammetry system is offered by ObjectARX and pipeline technology. An experiment is made in order to make sure the feasibility with the example of the software MAP-AT (Modern Aerial Photogrammetry Automatic Triangulation), the experimental results show that this scheme is feasible and it has very important meaning for the realization of the acquisition and edit integration.

A three-dimensional radiation image display on a real space image created via photogrammetry

NASA Astrophysics Data System (ADS)

Sato, Y.; Ozawa, S.; Tanifuji, Y.; Torii, T.

2018-03-01

The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., went into meltdown after the occurrence of a large tsunami caused by the Great East Japan Earthquake of March 11, 2011. The radiation distribution measurements inside the FDNPS buildings are indispensable to execute decommissioning tasks in the reactor buildings. We have developed a three-dimensional (3D) image reconstruction method for radioactive substances using a compact Compton camera. Moreover, we succeeded in visually recognizing the position of radioactive substances in real space by the integration of 3D radiation images and the 3D photo-model created using photogrammetry.

How large is the world's largest fish? Measuring whale sharks Rhincodon typus with laser photogrammetry.

PubMed

Rohner, C A; Richardson, A J; Marshall, A D; Weeks, S J; Pierce, S J

2011-01-01

Laser photogrammetry was found to be a promising new cost-effective technique for measuring free-swimming whale sharks Rhincodon typus. Photogrammetric measurements were more precise than visual size estimates by experienced researchers, with results from the two methods differing by 9· 8 ± 1· 1% (mean ±s.e.). A new metric of total length and the length between the fifth gill and first dorsal fin (r² = 0· 93) is proposed to facilitate easy, accurate length measurements of whale sharks in the field. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

Large Field Photogrammetry Techniques in Aircraft and Spacecraft Impact Testing

NASA Technical Reports Server (NTRS)

Littell, Justin D.

2010-01-01

The Landing and Impact Research Facility (LandIR) at NASA Langley Research Center is a 240 ft. high A-frame structure which is used for full-scale crash testing of aircraft and rotorcraft vehicles. Because the LandIR provides a unique capability to introduce impact velocities in the forward and vertical directions, it is also serving as the facility for landing tests on full-scale and sub-scale Orion spacecraft mass simulators. Recently, a three-dimensional photogrammetry system was acquired to assist with the gathering of vehicle flight data before, throughout and after the impact. This data provides the basis for the post-test analysis and data reduction. Experimental setups for pendulum swing tests on vehicles having both forward and vertical velocities can extend to 50 x 50 x 50 foot cubes, while weather, vehicle geometry, and other constraints make each experimental setup unique to each test. This paper will discuss the specific calibration techniques for large fields of views, camera and lens selection, data processing, as well as best practice techniques learned from using the large field of view photogrammetry on a multitude of crash and landing test scenarios unique to the LandIR.

Thanks to outgoing Associate Editors

NASA Astrophysics Data System (ADS)

Lichti, Derek D.; Weng, Qihao

2018-04-01

As of the end of December 2017, Professors Eberhard Gülch, Olaf Hellwich, Minho Kim, and Lalit Kumar have retired as Associate Editors of the ISPRS Journal of Photogrammetry and Remote Sensing. Our Journal's readership has benefited greatly from their longstanding commitment to their editorial duties. Both Profs. Gülch and Hellwich began their service to the Journal in 2007, while Profs. Kumar and Kim began in 2012 and 2014, respectively. In their many years as editors, they have witnessed the incredible growth of the Journal in terms of the number of papers submitted and published as well as the impact factor. Thanks to their high standards for paper quality and rigorous peer review, these professors have been important contributors to the Journal's current high standing. They were very versatile in terms of the scope of papers they could handle. Eberhard handled papers in photogrammetry, terrain modelling and geographic information systems (GIS) while Olaf handled papers in radar, computer vision and GIS. Both Lalit and Minho handled papers in optical remote sensing. On behalf of the Journal and the International Society for Photogrammetry and Remote Sensing, we thank them for many years of dedicated service to the Journal.

Photogrammetric Measurements of an EH-60L Brownout Cloud

NASA Technical Reports Server (NTRS)

Wong, Oliver D.; Tanner, Philip E.

2010-01-01

There is a critical lack of quantitative data regarding the mechanism of brownout cloud formation. Recognizing this, tests were conducted during the Air Force Research Lab 3D-LZ Brownout Test at the US Army Yuma Proving Ground. Photogrammetry was utilized during two rounds of flight tests with an instrumented EH-60L Black Hawk to determine if this technique could quantitatively measure the formation and evolution of a brownout cloud. Specific areas of interest include the location, size, and average convective velocity of the cloud, along with the characteristics of any defined structures within it. Following the first flight test, photogrammetric data were validated through comparison with onboard vehicle data. Lessons learned from this test were applied to the development of an improved photogrammetry system. A second flight test, utilizing the improved system, demonstrated that obtaining quantitative measurements of the brownout cloud are possible. Results from these measurements are presented in the paper. Flow visualization with chalk dust seeding was also tested. It was observed that pickup forces of the brownout cloud appear to be very low. Overall, these tests demonstrate the viability of photogrammetry as a means for quantifying brownout cloud formation and evolution.

Online, offline, realtime: recent developments in industrial photogrammetry

NASA Astrophysics Data System (ADS)

Boesemann, Werner

2003-01-01

In recent years industrial photogrammetry has emerged from a highly specialized niche technology to a well established tool in industrial coordinate measurement applications with numerous installations in a significantly growing market of flexible and portable optical measurement systems. This is due to the development of powerful, but affordable video and computer technology. The increasing industrial requirements for accuracy, speed, robustness and ease of use of these systems together with a demand for the highest possible degree of automation have forced universities and system manufacturer to develop hard- and software solutions to meet these requirements. The presentation will show the latest trends in hardware development, especially new generation digital and/or intelligent cameras, aspects of image engineering like use of controlled illumination or projection technologies, and algorithmic and software aspects like automation strategies or new camera models. The basic qualities of digital photogrammetry- like portability and flexibility on one hand and fully automated quality control on the other - sometimes lead to certain conflicts in the design of measurement systems for different online, offline, or real-time solutions. The presentation will further show, how these tools and methods are combined in different configurations to be able to cover the still growing demands of the industrial end-users.

Photogrammetric Metrology for the James Webb Space Telescope Integrated Science Instrument Module

NASA Technical Reports Server (NTRS)

Nowak, Maria; Crane, Allen; Davila, Pam; Eichhorn, William; Gill, James; Herrera, Acey; Hill, Michael; Hylan, Jason; Jetten, Mark; Marsh, James;

Direct local building inundation depth determination in 3-D point clouds generated from user-generated flood images

NASA Astrophysics Data System (ADS)

Griesbaum, Luisa; Marx, Sabrina; Höfle, Bernhard

2017-07-01

In recent years, the number of people affected by flooding caused by extreme weather events has increased considerably. In order to provide support in disaster recovery or to develop mitigation plans, accurate flood information is necessary. Particularly pluvial urban floods, characterized by high temporal and spatial variations, are not well documented. This study proposes a new, low-cost approach to determining local flood elevation and inundation depth of buildings based on user-generated flood images. It first applies close-range digital photogrammetry to generate a geo-referenced 3-D point cloud. Second, based on estimated camera orientation parameters, the flood level captured in a single flood image is mapped to the previously derived point cloud. The local flood elevation and the building inundation depth can then be derived automatically from the point cloud. The proposed method is carried out once for each of 66 different flood images showing the same building façade. An overall accuracy of 0.05 m with an uncertainty of ±0.13 m for the derived flood elevation within the area of interest as well as an accuracy of 0.13 m ± 0.10 m for the determined building inundation depth is achieved. Our results demonstrate that the proposed method can provide reliable flood information on a local scale using user-generated flood images as input. The approach can thus allow inundation depth maps to be derived even in complex urban environments with relatively high accuracies.

Skin movement artefact assessment and compensation in the estimation of knee-joint kinematics.

PubMed

Lucchetti, L; Cappozzo, A; Cappello, A; Della Croce, U

1998-11-01

In three dimensional (3-D) human movement analysis using close-range photogrammetry, surface marker clusters deform and rigidly move relative to the underlying bone. This introduces an important artefact (skin movement artefact) which propagates to bone position and orientation and joint kinematics estimates. This occurs to the extent that those joint attitude components that undergo small variations result in totally unreliable values. This paper presents an experimental and analytical procedure, to be included in a subject-specific movement analysis protocol, which allows for the assessment of skin movement artefacts and, based on this knowledge, for their compensation. The effectiveness of this procedure was verified with reference to knee-joint kinematics and to the artefacts caused by the hip movements on markers located on the thigh surface. Quantitative validation was achieved through experimental paradigms whereby prior reliable information on the target joint kinematics was available. When position and orientation of bones were determined during the execution of a motor task, using a least-squares optimal estimator, but the rigid artefactual marker cluster movement was not dealt with, then knee joint translations and rotations were affected by root mean square errors (r.m.s.) up to 14 mm and 6 degrees, respectively. When the rigid artefactual movement was also compensated for, then r.m.s errors were reduced to less than 4 mm and 3 degrees, respectively. In addition, errors originally strongly correlated with hip rotations, after compensation, lost this correlation.

Integration of aerial oblique imagery and terrestrial imagery for optimized 3D modeling in urban areas

NASA Astrophysics Data System (ADS)

Wu, Bo; Xie, Linfu; Hu, Han; Zhu, Qing; Yau, Eric

2018-05-01

Photorealistic three-dimensional (3D) models are fundamental to the spatial data infrastructure of a digital city, and have numerous potential applications in areas such as urban planning, urban management, urban monitoring, and urban environmental studies. Recent developments in aerial oblique photogrammetry based on aircraft or unmanned aerial vehicles (UAVs) offer promising techniques for 3D modeling. However, 3D models generated from aerial oblique imagery in urban areas with densely distributed high-rise buildings may show geometric defects and blurred textures, especially on building façades, due to problems such as occlusion and large camera tilt angles. Meanwhile, mobile mapping systems (MMSs) can capture terrestrial images of close-range objects from a complementary view on the ground at a high level of detail, but do not offer full coverage. The integration of aerial oblique imagery with terrestrial imagery offers promising opportunities to optimize 3D modeling in urban areas. This paper presents a novel method of integrating these two image types through automatic feature matching and combined bundle adjustment between them, and based on the integrated results to optimize the geometry and texture of the 3D models generated from aerial oblique imagery. Experimental analyses were conducted on two datasets of aerial and terrestrial images collected in Dortmund, Germany and in Hong Kong. The results indicate that the proposed approach effectively integrates images from the two platforms and thereby improves 3D modeling in urban areas.

Quality Assessment and Comparison of Smartphone and Leica C10 Laser Scanner Based Point Clouds

NASA Astrophysics Data System (ADS)

Sirmacek, Beril; Lindenbergh, Roderik; Wang, Jinhu

2016-06-01

3D urban models are valuable for urban map generation, environment monitoring, safety planning and educational purposes. For 3D measurement of urban structures, generally airborne laser scanning sensors or multi-view satellite images are used as a data source. However, close-range sensors (such as terrestrial laser scanners) and low cost cameras (which can generate point clouds based on photogrammetry) can provide denser sampling of 3D surface geometry. Unfortunately, terrestrial laser scanning sensors are expensive and trained persons are needed to use them for point cloud acquisition. A potential effective 3D modelling can be generated based on a low cost smartphone sensor. Herein, we show examples of using smartphone camera images to generate 3D models of urban structures. We compare a smartphone based 3D model of an example structure with a terrestrial laser scanning point cloud of the structure. This comparison gives us opportunity to discuss the differences in terms of geometrical correctness, as well as the advantages, disadvantages and limitations in data acquisition and processing. We also discuss how smartphone based point clouds can help to solve further problems with 3D urban model generation in a practical way. We show that terrestrial laser scanning point clouds which do not have color information can be colored using smartphones. The experiments, discussions and scientific findings might be insightful for the future studies in fast, easy and low-cost 3D urban model generation field.

Virtual in Real. Interactive Solutions for Learning and Communication in the National Archaeological Museum of Marche

NASA Astrophysics Data System (ADS)

Clini, P.; Nespeca, R.; Ruggeri, L.

2017-05-01

Today the ICTs are favourable additions to museum exhibitions. This work aims to realize an innovative system of digital exploitation of artefacts in the National Archaeological Museum of Marche (MANaM), in order to create a shared museum that will improve the knowledge of cultural contents through the paradigm "learning by interacting" and "edutainment". The main novelty is the implementation of stand-alone multimedia installations for digital artefacts that combine real and virtual scenarios in order to enrich the experience, the knowledge and the multi-sensory perception. A Digital Library (DL) is created using Close Range Photogrammetry (CRP) techniques applied to 21 archaeological artefacts belonging to different categories. Enriched with other data (texts, images, multimedia), all 3D models flow into the cloud data server from which are recalled in the individual exhibitions. In particular, we have chosen three types of technological solutions: VISUAL, TACTILE, SPATIAL. All the solutions take into account the possibility of group interaction, allowing the participation of the interaction to an appropriate number of users. Sharing the experience enables greater involvement, generating communicative effectiveness much higher than it would get from a lonely visit. From the "Museum Visitors Behaviour Analysis" we obtain a survey about users' needs and efficiency of the interactive solutions. The main result of this work is the educational impact in terms of increase in visitors, specially students, learning increase of historical and cultural content, greater user involvement during the visit to the museum.

Centenary of the Battle of Vimy (france, 1917): Preserving the Memory of the Great War Through 3d Recording of the Maison Blanche Souterraine

NASA Astrophysics Data System (ADS)

Murtiyoso, A.; Grussenmeyer, P.; Guillemin, S.; Prilaux, G.

2017-08-01

The Battle of Vimy Ridge was a military engagement between the Canadian Corps and the German Empire during the Great War (1914-1918). In this battle, Canadian troops fought as a single unit and won the day. It marked an important point in Canadian history as a nation. The year 2017 marks the centenary of this battle. In commemoration of this event, the Pas-de-Calais Departmental Council financed a 3D recording mission for one of the underground tunnels (souterraines) used as refuge by the Canadian soldiers several weeks prior to the battle. A combination of Terrestrial Laser Scanner (TLS) and close-range photogrammetry techniques was employed in order to document not only the souterraine, but also the various carvings and graffitis created by the soldiers on its walls. The resulting point clouds were registered to the French national geodetic system, and then meshed and textured in order to create a precise 3D model of the souterraine. In this paper, the workflow taken during the project as well as several results will be discussed. In the end, the resulting 3D model was used to create derivative products such as maps, section profiles, and also virtual visit videos. The latter helps the dissemination of the 3D information and thus aids in the preservation of the memory of the Great War for Canada.

Simulation of the erosion and drainage development of Loess surface based on GIS

NASA Astrophysics Data System (ADS)

Wang, Chun; Tang, Guoan; Ge, Shanshan; Li, Zhanbin; Zhou, Jieyu

2006-10-01

The research probes into the temporal-spatial process of drainage development of Loess Plateau on the basis of a carefully designed experiment. In the experiment, the development of a simulated loess watershed is tested under the condition of lab-simulated rainfall. A close-range photogrammetry survey is employed to establish a series of high precision and resolution DEM (Digit Elevation Model) of the simulated loess surface. Based on the established DEM, the erosion loss, the slope distribution, the topographic index , the gully-brink, and the drainage networks are all derived and discussed through comparison analysis and experimental validation. All the efforts aim at revealing the process and mechanism of erosion and drainage development of loess surface .This study demonstrates: 1) the stimulation result can effectively reflect the truth if those experimental conditions, i.e. loess soil structure, simulated rainfall, are adjusted in accord with true situation; 2) the remarkable character of the erosion and drainage up-growth of loess surface include the drainage traced to the source, the increased of the drainage's density, the enlarged of gully, the durative variety of multiple terrain factor's mean value and its distribution, such as slope and topographic index; 3) The slope spectrum is the more felicitous terrain factor for depicting the erosion and drainage development of loess surface, including the rule of erosion and evolution process. It is the new way and mean for studying the loess physiognomy.

Low aerial imagery - an assessment of georeferencing errors and the potential for use in environmental inventory

NASA Astrophysics Data System (ADS)

Smaczyński, Maciej; Medyńska-Gulij, Beata

2017-06-01

Unmanned aerial vehicles are increasingly being used in close range photogrammetry. Real-time observation of the Earth's surface and the photogrammetric images obtained are used as material for surveying and environmental inventory. The following study was conducted on a small area (approximately 1 ha). In such cases, the classical method of topographic mapping is not accurate enough. The geodetic method of topographic surveying, on the other hand, is an overly precise measurement technique for the purpose of inventorying the natural environment components. The author of the following study has proposed using the unmanned aerial vehicle technology and tying in the obtained images to the control point network established with the aid of GNSS technology. Georeferencing the acquired images and using them to create a photogrammetric model of the studied area enabled the researcher to perform calculations, which yielded a total root mean square error below 9 cm. The performed comparison of the real lengths of the vectors connecting the control points and their lengths calculated on the basis of the photogrammetric model made it possible to fully confirm the RMSE calculated and prove the usefulness of the UAV technology in observing terrain components for the purpose of environmental inventory. Such environmental components include, among others, elements of road infrastructure, green areas, but also changes in the location of moving pedestrians and vehicles, as well as other changes in the natural environment that are not registered on classical base maps or topographic maps.

Recording Information on Architectural Heritage Should Meet the Requirements for Conservation Digital Recording Practices at the Summer Palace

NASA Astrophysics Data System (ADS)

Zhang, L.; Cong, Y.; Wu, C.; Bai, C.; Wu, C.

2017-08-01

The recording of Architectural heritage information is the foundation of research, conservation, management, and the display of architectural heritage. In other words, the recording of architectural heritage information supports heritage research, conservation, management and architectural heritage display. What information do we record and collect and what technology do we use for information recording? How do we determine the level of accuracy required when recording architectural information? What method do we use for information recording? These questions should be addressed in relation to the nature of the particular heritage site and the specific conditions for the conservation work. In recent years, with the rapid development of information acquisition technology such as Close Range Photogrammetry, 3D Laser Scanning as well as high speed and high precision Aerial Photogrammetry, many Chinese universities, research institutes and heritage management bureaux have purchased considerable equipment for information recording. However, the lack of understanding of both the nature of architectural heritage and the purpose for which the information is being collected has led to several problems. For example: some institutions when recording architectural heritage information aim solely at high accuracy. Some consider that advanced measuring methods must automatically replace traditional measuring methods. Information collection becomes the purpose, rather than the means, of architectural heritage conservation. Addressing these issues, this paper briefly reviews the history of architectural heritage information recording at the Summer Palace (Yihe Yuan, first built in 1750), Beijing. Using the recording practices at the Summer Palace during the past ten years as examples, we illustrate our achievements and lessons in recording architectural heritage information with regard to the following aspects: (buildings') ideal status desired, (buildings') current status, structural distortion analysis, display, statue restoration and thematic research. Three points will be highlighted in our discussion: 1. Understanding of the heritage is more important than the particular technology used: Architectural heritage information collection and recording are based on an understanding of the value and nature of the architectural heritage. Understanding is the purpose, whereas information collection and recording are the means. 2. Demand determines technology: Collecting and recording architectural heritage information is to serve the needs of heritage research, conservation, management and display. These different needs determine the different technologies that we use. 3. Set the level of accuracy appropriately: For information recording, high accuracy is not the key criterion; rather an appropriate level of accuracy is key. There is considerable deviation between the nominal accuracy of any instrument and the accuracy of any particular measurement.

Generating High resolution surfaces from images: when photogrammetry and applied geophysics meets

NASA Astrophysics Data System (ADS)

Bretar, F.; Pierrot-Deseilligny, M.; Schelstraete, D.; Martin, O.; Quernet, P.

2012-04-01

Airborne digital photogrammetry has been used for some years to create digital models of the Earth's topography from calibrated cameras. But, in the recent years, the use of non-professionnal digital cameras has become valuable to reconstruct topographic surfaces. Today, the multi megapixel resolution of non-professionnal digital cameras, either used in a close range configuration or from low altitude flights, provide a ground pixel size of respectively a fraction of millimeters to couple of centimeters. Such advances turned into reality because the data processing chain made a tremendous break through during the last five years. This study investigates the potential of the open source software MICMAC developed by the French National Survey IGN (http://www.micmac.ign.fr) to calibrate unoriented digital images and calculate surface models of extremely high resolution for Earth Science purpose. We would like to report two experiences performed in 2011. The first has been performed in the context of risk assessment of rock falls and landslides along the cliffs of Normandy seashore. The acquisition protocol for the first site of "Criel-sur-Mer" has been very simple: a walk along the chalk vertical cliffs taking photos with a focal of 18mm every approx. 50m with an overlap of 80% allowed to generate 2.5km of digital surface at centimeter resolution. The site of "Les Vaches Noires" has been more complicated to acquire because of both the geology (dark clays) and the geometry (the landslide direction is parallel to the seashore and has a high field depth from the shore). We therefore developed an innovative device mounted on board of an autogyre (in-between ultralight power driven aircraft and helicopter). The entire area has been surveyed with a focal of 70mm at 400m asl with a ground pixel of 3cm. MICMAC gives the possibility to directly georeference digital Model. Here, it has been performed by a net of wireless GPS called Geocubes, also developed at IGN. The second experience is a part of field measurements performed over the flanks of the volcano Piton de la Fournaise, La Réunion island. In order to characterize the roughness of different type of lava flows, extremely high resolution Digital Terrain Models (0.6mm) have been generated with MICMAC. The use of such high definition topography made the characterization possible through the calculation of the correlation length, the standard deviation and the fractal dimension. To conclude, we will sketch a synthesis of the need of geoscientists vs. the optimal resolution of digital topographic data.

Quantifying ice cliff contribution to debris-covered glacier mass balance from multiple sensors

NASA Astrophysics Data System (ADS)

Brun, Fanny; Wagnon, Patrick; Berthier, Etienne; Kraaijenbrink, Philip; Immerzeel, Walter; Shea, Joseph; Vincent, Christian

2017-04-01

Ice cliffs on debris-covered glaciers have been recognized as a hot spot for glacier melt. Ice cliffs are steep (even sometimes overhanging) and fast evolving surface features, which make them challenging to monitor. We surveyed the topography of Changri Nup Glacier (Nepalese Himalayas, Everest region) in November 2015 and 2016 using multiple sensors: terrestrial photogrammetry, Unmanned Aerial Vehicle (UAV) photogrammetry, Pléiades stereo images and ASTER stereo images. We derived 3D point clouds and digital elevation models (DEMs) following a Structure-from-Motion (SfM) workflow for the first two sets of data to monitor surface elevation changes and calculate the associated volume loss. We derived only DEMs for the two last data sets. The derived DEMs had resolutions ranging from < 5 cm to 30 m. The derived point clouds and DEMs are used to quantify the ice melt of the cliffs at different scales. The very high resolution SfM point clouds, together with the surface velocity field, will be used to calculate the volume losses of 14 individual cliffs, depending on their size, aspect or the presence of supra glacial lake. Then we will extend this analysis to the whole glacier to quantify the contribution of ice cliff melt to the overall glacier mass balance, calculated with the UAV and Pléiades DEMs. This research will provide important tools to evaluate the role of ice cliffs in regional mass loss.

Simultaneous acquisition of 3D shape and deformation by combination of interferometric and correlation-based laser speckle metrology.

PubMed

Dekiff, Markus; Berssenbrügge, Philipp; Kemper, Björn; Denz, Cornelia; Dirksen, Dieter

2015-12-01

A metrology system combining three laser speckle measurement techniques for simultaneous determination of 3D shape and micro- and macroscopic deformations is presented. While microscopic deformations are determined by a combination of Digital Holographic Interferometry (DHI) and Digital Speckle Photography (DSP), macroscopic 3D shape, position and deformation are retrieved by photogrammetry based on digital image correlation of a projected laser speckle pattern. The photogrammetrically obtained data extend the measurement range of the DHI-DSP system and also increase the accuracy of the calculation of the sensitivity vector. Furthermore, a precise assignment of microscopic displacements to the object's macroscopic shape for enhanced visualization is achieved. The approach allows for fast measurements with a simple setup. Key parameters of the system are optimized, and its precision and measurement range are demonstrated. As application examples, the deformation of a mandible model and the shrinkage of dental impression material are measured.

Analysis of accuracy of digital elevation models created from captured data by digital photogrammetry method

NASA Astrophysics Data System (ADS)

Hudec, P.

2011-12-01

A digital elevation model (DEM) is an important part of many geoinformatic applications. For the creation of DEM, spatial data collected by geodetic measurements in the field, photogrammetric processing of aerial survey photographs, laser scanning and secondary sources (analogue maps) are used. It is very important from a user's point of view to know the vertical accuracy of a DEM. The article describes the verification of the vertical accuracy of a DEM for the region of Medzibodrožie, which was created using digital photogrammetry for the purposes of water resources management and modeling and resolving flood cases based on geodetic measurements in the field.

Development and Evaluation of a UAV-Photogrammetry System for Precise 3D Environmental Modeling.

PubMed

Shahbazi, Mozhdeh; Sohn, Gunho; Théau, Jérôme; Menard, Patrick

2015-10-30

The specific requirements of UAV-photogrammetry necessitate particular solutions for system development, which have mostly been ignored or not assessed adequately in recent studies. Accordingly, this paper presents the methodological and experimental aspects of correctly implementing a UAV-photogrammetry system. The hardware of the system consists of an electric-powered helicopter, a high-resolution digital camera and an inertial navigation system. The software of the system includes the in-house programs specifically designed for camera calibration, platform calibration, system integration, on-board data acquisition, flight planning and on-the-job self-calibration. The detailed features of the system are discussed, and solutions are proposed in order to enhance the system and its photogrammetric outputs. The developed system is extensively tested for precise modeling of the challenging environment of an open-pit gravel mine. The accuracy of the results is evaluated under various mapping conditions, including direct georeferencing and indirect georeferencing with different numbers, distributions and types of ground control points. Additionally, the effects of imaging configuration and network stability on modeling accuracy are assessed. The experiments demonstrated that 1.55 m horizontal and 3.16 m vertical absolute modeling accuracy could be achieved via direct geo-referencing, which was improved to 0.4 cm and 1.7 cm after indirect geo-referencing.

Indirect field technology for detecting areas object of illegal spills harmful to human health: application of drones, photogrammetry and hydrological models.

PubMed

Capolupo, Alessandra; Pindozzi, Stefania; Okello, Collins; Boccia, Lorenzo

2014-12-01

The accumulation of heavy metals in agricultural soils is a serious environmental problem. The Campania region in southern Italy has higher levels of cancer risk, presumably due to the accumulation of geogenic and anthropogenic soil pollutants, some of which have been incorporated into organic matter. The aim of this study was to introduce and test an innovative, field-applicable methodology to detect heavy metal accumulation using drone-based photogrammetry and microrill network modelling, specifically to generate wetlands wetlands prediction indices normally applied at large catchment scales, such as a large geographic basin. The processing of aerial photos taken using a hexacopter equipped with fifth-generation software for photogrammetry allowed the generation of a digital elevation model (DEM) with a resolution as high as 30 mm. Not only this provided a high potential for the study of micro-rill processes, but it was also useful for testing and comparing the capability of the topographic index (TI) and the clima-topographic index (CTI) to predict heavy metal sedimentation points at scales from 0.1 to 10 ha. Our results indicate that the TI and CTI indices can be used to predict points of heavy metal accumulation for small field catchments.

Development and Evaluation of a UAV-Photogrammetry System for Precise 3D Environmental Modeling

PubMed Central

Shahbazi, Mozhdeh; Sohn, Gunho; Théau, Jérôme; Menard, Patrick

2015-01-01

The specific requirements of UAV-photogrammetry necessitate particular solutions for system development, which have mostly been ignored or not assessed adequately in recent studies. Accordingly, this paper presents the methodological and experimental aspects of correctly implementing a UAV-photogrammetry system. The hardware of the system consists of an electric-powered helicopter, a high-resolution digital camera and an inertial navigation system. The software of the system includes the in-house programs specifically designed for camera calibration, platform calibration, system integration, on-board data acquisition, flight planning and on-the-job self-calibration. The detailed features of the system are discussed, and solutions are proposed in order to enhance the system and its photogrammetric outputs. The developed system is extensively tested for precise modeling of the challenging environment of an open-pit gravel mine. The accuracy of the results is evaluated under various mapping conditions, including direct georeferencing and indirect georeferencing with different numbers, distributions and types of ground control points. Additionally, the effects of imaging configuration and network stability on modeling accuracy are assessed. The experiments demonstrated that 1.55 m horizontal and 3.16 m vertical absolute modeling accuracy could be achieved via direct geo-referencing, which was improved to 0.4 cm and 1.7 cm after indirect geo-referencing. PMID:26528976

Uncooled Thermal Camera Calibration and Optimization of the Photogrammetry Process for UAV Applications in Agriculture

PubMed Central

Ballesteros, Rocío

2017-01-01

The acquisition, processing, and interpretation of thermal images from unmanned aerial vehicles (UAVs) is becoming a useful source of information for agronomic applications because of the higher temporal and spatial resolution of these products compared with those obtained from satellites. However, due to the low load capacity of the UAV they need to mount light, uncooled thermal cameras, where the microbolometer is not stabilized to a constant temperature. This makes the camera precision low for many applications. Additionally, the low contrast of the thermal images makes the photogrammetry process inaccurate, which result in large errors in the generation of orthoimages. In this research, we propose the use of new calibration algorithms, based on neural networks, which consider the sensor temperature and the digital response of the microbolometer as input data. In addition, we evaluate the use of the Wallis filter for improving the quality of the photogrammetry process using structure from motion software. With the proposed calibration algorithm, the measurement accuracy increased from 3.55 °C with the original camera configuration to 1.37 °C. The implementation of the Wallis filter increases the number of tie-point from 58,000 to 110,000 and decreases the total positing error from 7.1 m to 1.3 m. PMID:28946606

Relationship between postural alignment in sitting by photogrammetry and seated postural control in post-stroke subjects.

PubMed

Iyengar, Y R; Vijayakumar, K; Abraham, J M; Misri, Z K; Suresh, B V; Unnikrishnan, B

2014-01-01

This study was executed to find out correlation between postural alignment in sitting measured through photogrammetry and postural control in sitting following stroke. A cross-sectional study with convenient sampling consisting of 45 subjects with acute and sub-acute stroke. Postural alignment in sitting was measured through photogrammetry and relevant angles were obtained through software MB Ruler (version 5.0). Seated postural control was measured through Function in Sitting Test (FIST). Correlation was obtained using Spearman's Rank Correlation co-efficient in SPSS software (version 17.0). Moderate positive correlation (r = 0.385; p < 0.01) was found between angle of lordosis and angle between acromion, lateral epicondyle and point between radius and ulna. Strong negative correlation (r = -0.435; p < 0.01) was found between cranio-vertebral angle and kyphosis. FIST showed moderate positive correlation (r = 0.3446; p < 0.05) with cranio-vertebral angle and strong positive correlation (r = 0.4336; p < 0.01) with Brunnstrom's stage of recovery in upper extremity. Degree of forward head posture in sitting correlates directly with seated postural control and inversely with degree of kyphosis in sitting post-stroke. Postural control in sitting post-stroke is directly related with Brunnstrom's stage of recovery in affected upper extremity in sitting.

Uncooled Thermal Camera Calibration and Optimization of the Photogrammetry Process for UAV Applications in Agriculture.

PubMed

Ribeiro-Gomes, Krishna; Hernández-López, David; Ortega, José F; Ballesteros, Rocío; Poblete, Tomás; Moreno, Miguel A

2017-09-23

The acquisition, processing, and interpretation of thermal images from unmanned aerial vehicles (UAVs) is becoming a useful source of information for agronomic applications because of the higher temporal and spatial resolution of these products compared with those obtained from satellites. However, due to the low load capacity of the UAV they need to mount light, uncooled thermal cameras, where the microbolometer is not stabilized to a constant temperature. This makes the camera precision low for many applications. Additionally, the low contrast of the thermal images makes the photogrammetry process inaccurate, which result in large errors in the generation of orthoimages. In this research, we propose the use of new calibration algorithms, based on neural networks, which consider the sensor temperature and the digital response of the microbolometer as input data. In addition, we evaluate the use of the Wallis filter for improving the quality of the photogrammetry process using structure from motion software. With the proposed calibration algorithm, the measurement accuracy increased from 3.55 °C with the original camera configuration to 1.37 °C. The implementation of the Wallis filter increases the number of tie-point from 58,000 to 110,000 and decreases the total positing error from 7.1 m to 1.3 m.

Photogrammetry on glaciers: Old and new knowledge

NASA Astrophysics Data System (ADS)

Pfeffer, W. T.; Welty, E.; O'Neel, S.

2014-12-01

In the past few decades terrestrial photogrammetry has become a widely used tool for glaciological research, brought about in part by the proliferation of high-quality, low-cost digital cameras, dramatic increases in image-processing power of computers, and very innovative progress in image processing, much of which has come from computer vision research and from the computer gaming industry. At present, glaciologists have developed their capacity to gather images much further than their ability to process them. Many researchers have accumulated vast inventories of imagery, but have no efficient means to extract the data they desire from them. In many cases these are single-image time series where the processing limitation lies in the paucity of methods to obtain 3-dimension object space information from measurements in the 2-dimensional image space; in other cases camera pairs have been operated but no automated means is in hand for conventional stereometric analysis of many thousands of image pairs. Often the processing task is further complicated by weak camera geometry or ground control distribution, either of which will compromise the quality of 3-dimensional object space solutions. Solutions exist for many of these problems, found sometimes among the latest computer vision results, and sometimes buried in decades-old pre-digital terrestrial photogrammetric literature. Other problems, particularly those arising from poorly constrained or underdetermined camera and ground control geometry, may be unsolvable. Small-scale, ground-based photography and photogrammetry of glaciers has grown over the past few decades in an organic and disorganized fashion, with much duplication of effort and little coordination or sharing of knowledge among researchers. Given the utility of terrestrial photogrammetry, its low cost (if properly developed and implemented), and the substantial value of the information to be had from it, some further effort to share knowledge and methods would be a great benefit for the community. We consider some of the main problems to be solved, and aspects of how optimal knowledge sharing might be accomplished.

Comparison of glacier loss on Qori Kalis, Peru and Mt. Kilimanjaro, Tanzania over the last decade using digital photogrammetry and stereo analysis

NASA Astrophysics Data System (ADS)

Lamantia, K.

2017-12-01

Rising global temperatures have created cause for concern, particularly among those who study the world's glaciers. Given their high sensitivity to climate change tropical glaciers can be used not only as indicators of change but can provide information necessary for more accurate interpretations of the mechanisms driving climate change. In the past, measurements of glacier extent changes such as for the Qori Kalis Glacier in Peru have been based on terrestrial photography and hand-plotted photogrammetry. Recent technological advances now provide an opportunity to modify the way these glaciers are observed and measured. New developments have opened doors for digital photogrammetry software such as the Leica Photogrammetry Suite and stereo analyst from ERDAS, which offers stereoscopic tools with the ability to plot the ice extent in a three dimensional image. At least two images from different perspectives are required to create the file for stereo analysis. The resulting three-dimensional digital content will offer more flexibility in analysis, quantification, and visualization for better documentation of retreating glaciers. It is possible to produce both two-and three-dimensional surface area estimations for glaciers such as Qori Kalis and the Kilimanjaro ice fields. Beyond a surface area measurement, the software also possesses the capability to create contours for the surface of the glacier as well as view and analyze properties such as slope and aspect. The surface area measurements taken with the digital method are compared with the hand-plotted measurements made in the past and are found to be comparable. A comparison of glacier loss over time as well as a comparison between both tropical locations, will be presented and should provide better insight to the drivers that are influencing current glacier loss. Making the transition from terrestrial, to aerial, and now to satellite imagery provides a simpler method for accessing and assessing changes in glaciated regions of the world.

Digital mono- and 3D stereo-photogrammetry for geological and geomorphological mapping

NASA Astrophysics Data System (ADS)

Scapozza, Cristian; Schenker, Filippo Luca; Castelletti, Claudio; Bozzini, Claudio; Ambrosi, Christian

2016-04-01

The generalization of application of digital tools for managing, mapping and updating geological data have become widely accepted in the last decennia. Despite the increasing quality and availability of digital topographical maps, orthorectified aerial photographs (orthophotos) and high resolution (5 up to 0.5 m) Digital Elevation Models (DEMs), a correct recognition of the kind, the nature and the boundaries of geological formations and geomophological landforms, unconsolidated sedimentary deposits or slope instabilities is often very difficult on conventional two-dimensional (2D) products, in particular in steep zones (rock walls and talus slopes), under the forest cover, for a very complex topography and in deeply urbanised zones. In many cases, photo-interpretative maps drawn only by 2D data sets must be improved by field verifications or, at least, by field oblique photographs. This is logical, because our natural perception of the real world is three-dimensional (3D), which is partially disabled by the application of 2D visualization techniques. Here we present some examples of application of digital mapping based on a 3D visualization (for aerial and satellite images photo-interpretation) or on a terrestrial perception by digital mono-photogrammetry (for oblique photographs). The 3D digital mapping was performed thanks to an extension of the software ESRI® ArcGIS™ called ArcGDS™. This methodology was also applied on historical aerial photographs (normally analysed by optical stereo-photogrammetry), which were digitized by scanning and then oriented and aero-triangulated thanks to the ArcGDS™ software, allowing the 3D visualisation and the mapping in a GIS environment (Ambrosi and Scapozza, 2015). The mono-photogrammetry (or monoplotting) is the technique of photogrammetrical georeferentiation of single oblique unrectified photographs, which are related to a DEM. In other words, the monoplotting allows relating each pixel of the photograph to the corresponding real world pixel on the DEM, and then extract georeferenced vector data and orthorectified raster data from terrestrial photographs (Bozzini et al., 2012; Scapozza et al., 2014). Through some case studies, we show (1) how 3D digital stereo-photogrammetry makes it possible the production of Quaternary geological and geomorphological maps, (2) how digital mono-photogrammetry is a powerful tool for supporting geological mapping in very steep zones and (3) how the combination of these two digital tools permits diachronical mapping of phenomena evolution (such as landslides or rockglaciers) during the entire twentieth century. Ambrosi C. and Scapozza C. 2015. Improvements in 3-D digital mapping for geomorphological and Quaternary geological cartography. Geographica Helvetica 70: 121-133. doi: 10.5194/gh-70-121-2015 Bozzini C., Conedera M. and Krebs P. 2012. A new monoplotting tool to extract georeferenced vector data and orthorectified raster data from oblique non-metric photographs. International Journal of Heritage in the Digital Era 1: 499-518. doi: 10.1260/2047-4970.1.3.499 Scapozza C., Lambiel C., Bozzini C., Mari S. and Conedera M. 2014. Assessing the rock glacier kinematics on three different timescales: a case study from the southern Swiss Alps. Earth Surface Processes and Landforms 39: 2056-2069. doi: 10.1002/esp.3599

Investigating historical changes in morphodynamic processes associated with channelization of a large Alpine river: the Etsch/Adige River, NE Italy

NASA Astrophysics Data System (ADS)

Zen, Simone; Scorpio, Vittoria; Mastronunzio, Marco; Proto, Matteo; Zolezzi, Guido; Bertoldi, Walter; Comiti, Francesco; Surian, Nicola; Prà, Elena Dai

2016-04-01

River channel management within the last centuries has largely modified fluvial processes and morphodynamic evolution of most large European rivers. Several river systems experienced extensive channelization early in the 19th century, thus strongly challenging our present ability to detect their morphodynamic functioning with contemporary photogrammetry or cartographical sources. This consequently leaves open questions about their potential future response, especially to management strategies that "give more room" to the river, aiming at partially rehabilitating their natural functioning. The Adige River (Etsch in German), the second longest Italian river, is an exemplary case where channelization occurred more than 150 years ago, and is the focus of the present work. This work aims (i) to explore changes in fundamental morphodynamic processes associated with massive channelization of the Adige River and (ii) to quantify the alteration in river bars characteristics, by using morphodynamic models of bars and meandering. To fulfil our aims we combine the analysis of historical data with morphodynamic mathematical modelling. Historical sources (recovered in a number of European archives), such as hydrotopographical maps, airborne photogrammetry and hydrological datasets were collected to investigate channel morphology before and after the channelization. Information extracted from this analysis was combined with morphodynamic linear models of free migrating and forced steady bars, to investigate river bars and bend stability properties under different hydromorphological scenarios. Moreover, a morphodynamic model for meandering channel was applied to investigate the influence of river channel planform on the evolution of the fluvial bars. Results from the application of morphodynamic models allowed to predict the type, position and geometry of bars characterizing the channelized configuration of the river, and to explain the presently observed relative paucity of bars if compared to the previous, less confined, river planform. The application of a meander model allows insight into the properties of bars that were observed in the old historical maps. A threshold range of the imposed channel width can be predicted above which the river may partially restore conditions for bar instability to occur and for their further development, with direct management implications. Overall the conducted analysis confirms the potential of integrating morphodynamic models with geomorphological and time-series analysis of historical large-scale maps and airborne photogrammetry to increase our understanding and predictive ability of the evolution of rivers with a long-lasting record of morphological regulation.

Textbooks and technical references for remote sensing

NASA Technical Reports Server (NTRS)

Rudd, R. D.; Bowden, L. W.; Colwell, R. N.; Estes, J. E.

1980-01-01

A selective bibliography is presented which cites 89 textbooks, monographs, and articles covering introductory and advanced remote sensing techniques, photointerpretation, photogrammetry, and image processing.

Uav Photogrammetry for Mapping and Monitoring of Northern Permafrost Landscapes

NASA Astrophysics Data System (ADS)

Fraser, R. H.; Olthof, I.; Maloley, M.; Fernandes, R.; Prevost, C.; van der Sluijs, J.

2015-08-01

Northern environments are changing in response to recent climate warming, resource development, and natural disturbances. The Arctic climate has warmed by 2-3°C since the 1950's, causing a range of cryospheric changes including declines in sea ice extent, snow cover duration, and glacier mass, and warming permafrost. The terrestrial Arctic has also undergone significant temperature-driven changes in the form of increased thermokarst, larger tundra fires, and enhanced shrub growth. Monitoring these changes to inform land managers and decision makers is challenging due to the vast spatial extents involved and difficult access. Environmental monitoring in Canada's North is often based on local-scale measurements derived from aerial reconnaissance and photography, and ecological, hydrologic, and geologic sampling and surveying. Satellite remote sensing can provide a complementary tool for more spatially comprehensive monitoring but at coarser spatial resolutions. Satellite remote sensing has been used to map Arctic landscape changes related to vegetation productivity, lake expansion and drainage, glacier retreat, thermokarst, and wildfire activity. However, a current limitation with existing satellite-based techniques is the measurement gap between field measurements and high resolution satellite imagery. Bridging this gap is important for scaling up field measurements to landscape levels, and validating and calibrating satellite-based analyses. This gap can be filled to a certain extent using helicopter or fixed-wing aerial surveys, but at a cost that is often prohibitive. Unmanned aerial vehicle (UAV) technology has only recently progressed to the point where it can provide an inexpensive and efficient means of capturing imagery at this middle scale of measurement with detail that is adequate to interpret Arctic vegetation (i.e. 1-5 cm) and coverage that can be directly related to satellite imagery (1-10 km2). Unlike satellite measurements, UAVs permit frequent surveys (e.g. for monitoring vegetation phenology, fires, and hydrology), are not constrained by repeat cycle or cloud cover, can be rapidly deployed following a significant event, and are better suited than manned aircraft for mapping small areas. UAVs are becoming more common for agriculture, law enforcement, and marketing, but their use in the Arctic is still rare and represents untapped technology for northern mapping, monitoring, and environmental research. We are conducting surveys over a range of sensitive or changing northern landscapes using a variety of UAV multicopter platforms and small sensors. Survey targets include retrogressive thaw slumps, tundra shrub vegetation, recently burned vegetation, road infrastructure, and snow. Working with scientific partners involved in northern monitoring programs (NWT CIMP, CHARS, NASA ABOVE, NRCan-GSC) we are investigating the advantages, challenges, and best practices for acquiring high resolution imagery from multicopters to create detailed orthomosaics and co-registered 3D terrain models. Colour and multispectral orthomosaics are being integrated with field measurements and satellite imagery to conduct spatial scaling of environmental parameters. Highly detailed digital terrain models derived using structure from motion (SfM) photogrammetry are being applied to measure thaw slump morphology and change, snow depth, tundra vegetation structure, and surface condition of road infrastructure. These surveys and monitoring applications demonstrate that UAV-based photogrammetry is poised to make a rapid contribution to a wide range of northern monitoring and research applications.

Laser-Induced Fluorescence Photogrammetry for Dynamic Characterization of Transparent and Aluminized Membrane Structures

NASA Technical Reports Server (NTRS)

Dorrington, Adrian A.; Jones, Thomas W.; Danehy, Paul M.; Pappa, Richard S.

2003-01-01

Photogrammetry has proven to be a valuable tool for static and dynamic profiling of membrane based inflatable and ultra-lightweight space structures. However, the traditional photogrammetric targeting techniques used for solid structures, such as attached retro-reflective targets and white-light dot projection, have some disadvantages and are not ideally suited for measuring highly transparent or reflective membrane structures. In this paper, we describe a new laser-induced fluorescence based target generation technique that is more suitable for these types of structures. We also present several examples of non-contact non-invasive photogrammetric measurements of laser-dye doped polymers, including the dynamic measurement and modal analysis of a 1m-by-1m aluminized solar sail style membrane.

Simultaneous, Unsteady PIV and Photogrammetry Measurements of a Tension-Cone Decelerator in Subsonic Flow

NASA Technical Reports Server (NTRS)

Schairer, Edward T.; Heineck, James T.; Walker, Louise Ann; Kushner, Laura Kathryn; Zilliac, Gregory

2010-01-01

This paper describes simultaneous, synchronized, high-frequency measurements of both unsteady flow in the wake of a tension-cone decelerator in subsonic flow (by PIV) and the unsteady shape of the decelerator (by photogrammetry). The purpose of these measurements was to develop the test techniques necessary to validate numerical methods for computing fluid-structure interactions of flexible decelerators. A critical need for this effort is to map fabric surfaces that have buckled or wrinkled so that code developers can accurately represent them. This paper describes a new photogrammetric technique that performs this measurement. The work was done in support of the Entry, Descent, and Landing discipline within the Supersonics Project of NASA s Fundamental Aeronautics Program.

The use of heterodyne speckle photogrammetry to measure high-temperature strain distributions

NASA Technical Reports Server (NTRS)

Stetson, K. A.

1983-01-01

Thermal and mechanical strains have been measured on samples of a common material used in jet engine burner liners, which were heated from room temperature to 870 C and cooled back to 220 C, in a laboratory furnace. The physical geometry of the sample surface was recorded to select temperatures by means of a set of twelve single-exposure specklegrams. Sequential pairs of specklegrams were compared in a heterodyne interferometer which allowed high-precision measurement of differential displacements. Good speckle correlation was observed between the first and last specklegrams also, which showed the durability of the surface microstructure, and permitted a check on accumulated errors. Agreement with calculated thermal expansion was to within a few hundred microstrain over a range of fourteen thousand.

Low altitude aerial photogrammetry application to braided river systems. Example of the Buech River, Alps, France.

NASA Astrophysics Data System (ADS)

Jules Fleury, Thomas; Pothin, Virginie; Vella, Claude; Dussouillez, Philippe; Izem, Abdelkoddouss

2015-04-01

Low-altitude aerial photogrammetry offers new opportunities for geomorphology and other fields requiring very high-resolution topographic data. It combines the advantages of the reproducibility of GPS topographic surveys with the high accuracy of LIDAR, but at relatively low-cost, easy-to-deploy and with the synaptic advantage of remote sensing. In order to evaluate the potential of photogrammetry on river systems and to assess river-bed changes and erosion-accretion processes, we conducted several surveys over the period of one year on the Buech river, a gravel-bed braided river located in the French Southern Alps. The study area is located directly upstream of a gravel pit and there is an interest in evaluating its effects on the riverbed. Our field protocol was comprised of vertical aerial photographs taken from a microlight aircraft flying approximately 300 ft above the ground. The equipment used was a full-frame DSLR with a wide angle lense, synchronised with a DGPS onboard. Fourty 40cm wide targets were placed on the ground and georeferenced by RTK DGPS with an accuracy of 2cm. In addition, close to one thousand Ground Control Points (GCPs) were measured within the different types of ground surfaces (vegetated, water, gravels) in order to assess the Digital Terrain Model (DTM) accuracy. We operated the production of the 3D model and its derived products: Digital Surface Model (DSM) and orthophotography, with user-friendly Agisoft (c) Photoscan Professional software. The processing of several hundred pictures with 2.5 cm ground resolution resulted in a DSM with a resolution of 10 cm and a vertical accuracy within 5 cm. As is expected, accuracy was best on bare bars and decreased with increasing vegetation density. To complement the DSM in the wetted channels, we used the orthophotos to establish a relationship between water color and flow depth using statistical multivariate regressions. Merging the bathymetric model and the DSM produced a DTM with a vertical accuracy within 10cm. Subtle riverbed micro-morphologies (cm to m) not visible using classical techniques could be mapped : individual gravels, scour and deposition around woody debris, intra-bar channels, vertical bar faces etc. Multiple acquisitions combined have permit quantification of volumes eroded or accumulated during an hydrological event. The exceptional quality of the results obtained using this technique, both quantitative and qualitative, offers exciting new prospects for fluvial geomorphic studies. The limitations surrounding this technique include : the large volume of data produced, processing time, the large number of GCPs required to constraint the model and the lack of a NIR channel for image classification.

Game of thrown bombs in 3D: using high speed cameras and photogrammetry techniques to reconstruct bomb trajectories at Stromboli (Italy)

NASA Astrophysics Data System (ADS)

Gaudin, D.; Taddeucci, J.; Scarlato, P.; Del Bello, E.; Houghton, B. F.; Orr, T. R.; Andronico, D.; Kueppers, U.

2015-12-01

Large juvenile bombs and lithic clasts, produced and ejected during explosive volcanic eruptions, follow ballistic trajectories. Of particular interest are: 1) the determination of ejection velocity and launch angle, which give insights into shallow conduit conditions and geometry; 2) particle trajectories, with an eye on trajectory evolution caused by collisions between bombs, as well as the interaction between bombs and ash/gas plumes; and 3) the computation of the final emplacement of bomb-sized clasts, which is important for hazard assessment and risk management. Ground-based imagery from a single camera only allows the reconstruction of bomb trajectories in a plan perpendicular to the line of sight, which may lead to underestimation of bomb velocities and does not allow the directionality of the ejections to be studied. To overcome this limitation, we adapted photogrammetry techniques to reconstruct 3D bomb trajectories from two or three synchronized high-speed video cameras. In particular, we modified existing algorithms to consider the errors that may arise from the very high velocity of the particles and the impossibility of measuring tie points close to the scene. Our method was tested during two field campaigns at Stromboli. In 2014, two high-speed cameras with a 500 Hz frame rate and a ~2 cm resolution were set up ~350m from the crater, 10° apart and synchronized. The experiment was repeated with similar parameters in 2015, but using three high-speed cameras in order to significantly reduce uncertainties and allow their estimation. Trajectory analyses for tens of bombs at various times allowed for the identification of shifts in the mean directivity and dispersal angle of the jets during the explosions. These time evolutions are also visible on the permanent video-camera monitoring system, demonstrating the applicability of our method to all kinds of explosive volcanoes.

Surveying Medieval Archaeology: a New Form for Harris Paradigm Linking Photogrammetry and Temporal Relations

NASA Astrophysics Data System (ADS)

Drap, P.; Papini, O.; Pruno, E.; Nucciotti, M.; Vannini, G.

2017-02-01

The paper presents some reflexions concerning an interdisciplinary project between Medieval Archaeologists from the University of Florence (Italy) and ICT researchers from CNRS LSIS of Marseille (France), aiming towards a connection between 3D spatial representation and archaeological knowledge. It is well known that Laser Scanner, Photogrammetry and Computer Vision are very attractive tools for archaeologists, although the integration of representation of space and representation of archaeological time has not yet found a methodological standard of reference. We try to develop an integrated system for archaeological 3D survey and all other types of archaeological data and knowledge through integrating observable (material) and non-graphic (interpretive) data. Survey plays a central role, since it is both a metric representation of the archaeological site and, to a wider extent, an interpretation of it (being also a common basis for communication between the 2 teams). More specifically 3D survey is crucial, allowing archaeologists to connect actual spatial assets to the stratigraphic formation processes (i.e. to the archaeological time) and to translate spatial observations into historical interpretation of the site. We propose a common formalism for describing photogrammetrical survey and archaeological knowledge stemming from ontologies: Indeed, ontologies are fully used to model and store 3D data and archaeological knowledge. Xe equip this formalism with a qualitative representation of time. Stratigraphic analyses (both of excavated deposits and of upstanding structures) are closely related to E. C. Harris theory of "Stratigraphic Unit" ("US" from now on). Every US is connected to the others by geometric, topological and, eventually, temporal links, and are recorded by the 3D photogrammetric survey. However, the limitations of the Harris Matrix approach lead to use another representation formalism for stratigraphic relationships, namely Qualitative Constraints Networks (QCN) successfully used in the domain of knowledge representation and reasoning in artificial intelligence for representing temporal relations.

UAV Photogrammetry of Inflated Komatiite Flow Lobes in an Archean Bimodal Volcanic Terrane, Yilgarn Craton, Western Australia

NASA Astrophysics Data System (ADS)

Barnes, S. J.; Dering, G.

2016-12-01

Previous studies of large komatiite fields in Archean greenstone belts in Western Australia and elsewhere have led to the suggestion that komatiite lavas were emplaced by similar mechanisms to modern pahoehoe flows, notwithstanding the very low viscosities and sea-floor eruption setting. Of komatiites. We use UAV photogrammetry to identify and map inflation features characteristic of modern pahoehoe flows in Archean komatiites at the Gordon Sirdar Lake locality near Kalgoorlie. Komatiite lavas, forming part of the 2705 Ma old plume-related bimodal volcanic sequence of the Eastern Goldfields Superterrane, Yilgarn Craton, were emplaced within a sequence of dacitic lava flows and semi-consolidated tuffs. The sequence was tilted to the vertical on the flanks of a regional isoclinal fold, and is exposed as partially weathered outcrop in the bed of a playa lake. Komatiite lava lobes form characteristic lenticular cross sections ranging from 1-6 m thick and up to 20m long, in some cases with lower margins draped over pre-existing dacite flow tops, and in others showing invasive textures implying eruption onto or into wet sediment. Inflation features include tumuli, inflation clefts, breakouts, and terraced margins. Spinifex textures are preserved locally at flow tops and rarely at bases. High temperature (>1400 C) and low viscosities (<50 Pa s) of komatiites evidently do not preclude inflation as an emplacement mechanism of individual flows. Flow-top morphology has been used to identify inflation of basaltic lava flows in Martian environments. We suggest these criteria may be extended to the possible recognition of Martian komatiites.

Patient-specific polyetheretherketone facial implants in a computer-aided planning workflow.

PubMed

Guevara-Rojas, Godoberto; Figl, Michael; Schicho, Kurt; Seemann, Rudolf; Traxler, Hannes; Vacariu, Apostolos; Carbon, Claus-Christian; Ewers, Rolf; Watzinger, Franz

2014-09-01

In the present study, we report an innovative workflow using polyetheretherketone (PEEK) patient-specific implants for esthetic corrections in the facial region through onlay grafting. The planning includes implant design according to virtual osteotomy and generation of a subtraction volume. The implant design was refined by stepwise changing the implant geometry according to soft tissue simulations. One patient was scanned using computed tomography. PEEK implants were interactively designed and manufactured using rapid prototyping techniques. Positioning intraoperatively was assisted by computer-aided navigation. Two months after surgery, a 3-dimensional surface model of the patient's face was generated using photogrammetry. Finally, the Hausdorff distance calculation was used to quantify the overall error, encompassing the failures in soft tissue simulation and implantation. The implant positioning process during surgery was satisfactory. The simulated soft tissue surface and the photogrammetry scan of the patient showed a high correspondence, especially where the skin covered the implants. The mean total error (Hausdorff distance) was 0.81 ± 1.00 mm (median 0.48, interquartile range 1.11). The spatial deviation remained less than 0.7 mm for the vast majority of points. The proposed workflow provides a complete computer-aided design, computer-aided manufacturing, and computer-aided surgery chain for implant design, allowing for soft tissue simulation, fabrication of patient-specific implants, and image-guided surgery to position the implants. Much of the surgical complexity resulting from osteotomies of the zygoma, chin, or mandibular angle might be transferred into the planning phase of patient-specific implants. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Autocorrelation techniques for soft photogrammetry

NASA Astrophysics Data System (ADS)

Yao, Wu

In this thesis research is carried out on image processing, image matching searching strategies, feature type and image matching, and optimal window size in image matching. To make comparisons, the soft photogrammetry package SoftPlotter is used. Two aerial photographs from the Iowa State University campus high flight 94 are scanned into digital format. In order to create a stereo model from them, interior orientation, single photograph rectification and stereo rectification are done. Two new image matching methods, multi-method image matching (MMIM) and unsquare window image matching are developed and compared. MMIM is used to determine the optimal window size in image matching. Twenty four check points from four different types of ground features are used for checking the results from image matching. Comparison between these four types of ground feature shows that the methods developed here improve the speed and the precision of image matching. A process called direct transformation is described and compared with the multiple steps in image processing. The results from image processing are consistent with those from SoftPlotter. A modified LAN image header is developed and used to store the information about the stereo model and image matching. A comparison is also made between cross correlation image matching (CCIM), least difference image matching (LDIM) and least square image matching (LSIM). The quality of image matching in relation to ground features are compared using two methods developed in this study, the coefficient surface for CCIM and the difference surface for LDIM. To reduce the amount of computation in image matching, the best-track searching algorithm, developed in this research, is used instead of the whole range searching algorithm.

Study of wave runup using numerical models and low-altitude aerial photogrammetry: A tool for coastal management

NASA Astrophysics Data System (ADS)

Casella, Elisa; Rovere, Alessio; Pedroncini, Andrea; Mucerino, Luigi; Casella, Marco; Cusati, Luis Alberto; Vacchi, Matteo; Ferrari, Marco; Firpo, Marco

2014-08-01

Monitoring the impact of sea storms on coastal areas is fundamental to study beach evolution and the vulnerability of low-lying coasts to erosion and flooding. Modelling wave runup on a beach is possible, but it requires accurate topographic data and model tuning, that can be done comparing observed and modeled runup. In this study we collected aerial photos using an Unmanned Aerial Vehicle after two different swells on the same study area. We merged the point cloud obtained with photogrammetry with multibeam data, in order to obtain a complete beach topography. Then, on each set of rectified and georeferenced UAV orthophotos, we identified the maximum wave runup for both events recognizing the wet area left by the waves. We then used our topography and numerical models to simulate the wave runup and compare the model results to observed values during the two events. Our results highlight the potential of the methodology presented, which integrates UAV platforms, photogrammetry and Geographic Information Systems to provide faster and cheaper information on beach topography and geomorphology compared with traditional techniques without losing in accuracy. We use the results obtained from this technique as a topographic base for a model that calculates runup for the two swells. The observed and modeled runups are consistent, and open new directions for future research.

Study of Lever-Arm Effect Using Embedded Photogrammetry and On-Board GPS Receiver on Uav for Metrological Mapping Purpose and Proposal of a Free Ground Measurements Calibration Procedure

NASA Astrophysics Data System (ADS)

Daakir, M.; Pierrot-Deseilligny, M.; Bosser, P.; Pichard, F.; Thom, C.; Rabot, Y.

2016-03-01

Nowadays, Unmanned Aerial Vehicle (UAV) on-board photogrammetry knows a significant growth due to the democratization of using drones in the civilian sector. Also, due to changes in regulations laws governing the rules of inclusion of a UAV in the airspace which become suitable for the development of professional activities. Fields of application of photogrammetry are diverse, for instance: architecture, geology, archaeology, mapping, industrial metrology, etc. Our research concerns the latter area. Vinci-Construction- Terrassement is a private company specialized in public earthworks that uses UAVs for metrology applications. This article deals with maximum accuracy one can achieve with a coupled camera and GPS receiver system for direct-georeferencing of Digital Surface Models (DSMs) without relying on Ground Control Points (GCPs) measurements. This article focuses specially on the lever-arm calibration part. This proposed calibration method is based on two steps: a first step involves the proper calibration for each sensor, i.e. to determine the position of the optical center of the camera and the GPS antenna phase center in a local coordinate system relative to the sensor. A second step concerns a 3d modeling of the UAV with embedded sensors through a photogrammetric acquisition. Processing this acquisition allows to determine the value of the lever-arm offset without using GCPs.

Reliability of photogrammetry in the evaluation of the postural aspects of individuals with structural scoliosis.

PubMed

Saad, Karen Ruggeri; Colombo, Alexandra Siqueira; Ribeiro, Ana Paula; João, Sílvia Maria Amado

2012-04-01

The purpose of this study was to investigate the reliability of photogrammetry in the measurement of the postural deviations in individuals with idiopathic scoliosis. Twenty participants with scoliosis (17 women and three men), with a mean age of 23.1 ± 9 yrs, were photographed from the posterior and lateral views. The postural aspects were measured with CorelDRAW software. High inter-rater and test-retest reliability indices were found. It was observed that with more severity of scoliosis, greater were the variations between the thoracic kyphosis and lumbar lordosis measures obtained by the same examiner from the left lateral view photographs. A greater body mass index (BMI) was associated with greater variability of the trunk rotation measures obtained by two independent examiners from the right, lateral view (r = 0.656; p = 0.002). The severity of scoliosis was also associated with greater inter-rater variability measures of trunk rotation obtained from the left, lateral view (r = 0.483; p = 0.036). Photogrammetry demonstrated to be a reliable method for the measurement of postural deviations from the posterior and lateral views of individuals with idiopathic scoliosis and could be complementarily employed for the assessment procedures, which could reduce the number of X-rays used for the follow-up assessments of these individuals. Copyright © 2011 Elsevier Ltd. All rights reserved.

Absolute surface reconstruction by slope metrology and photogrammetry

NASA Astrophysics Data System (ADS)

Dong, Yue

Developing the manufacture of aspheric and freeform optical elements requires an advanced metrology method which is capable of inspecting these elements with arbitrary freeform surfaces. In this dissertation, a new surface measurement scheme is investigated for such a purpose, which is to measure the absolute surface shape of an object under test through its surface slope information obtained by photogrammetric measurement. A laser beam propagating toward the object reflects on its surface while the vectors of the incident and reflected beams are evaluated from the four spots they leave on the two parallel transparent windows in front of the object. The spots' spatial coordinates are determined by photogrammetry. With the knowledge of the incident and reflected beam vectors, the local slope information of the object surface is obtained through vector calculus and finally yields the absolute object surface profile by a reconstruction algorithm. An experimental setup is designed and the proposed measuring principle is experimentally demonstrated by measuring the absolute surface shape of a spherical mirror. The measurement uncertainty is analyzed, and efforts for improvement are made accordingly. In particular, structured windows are designed and fabricated to generate uniform scattering spots left by the transmitted laser beams. Calibration of the fringe reflection instrument, another typical surface slope measurement method, is also reported in the dissertation. Finally, a method for uncertainty analysis of a photogrammetry measurement system by optical simulation is investigated.

Concordance and Reliability of Photogrammetric Protocols for Measuring the Cervical Lordosis Angle: A Systematic Review of the Literature.

PubMed

de Albuquerque, Priscila Maria Nascimento Martins; de Alencar, Geisa Guimarães; de Oliveira, Daniela Araújo; de Siqueira, Gisela Rocha

2018-01-01

The aim of this study was to examine and interpret the concordance, accuracy, and reliability of photogrammetric protocols available in the literature for evaluating cervical lordosis in an adult population aged 18 to 59 years. A systematic search of 6 electronic databases (MEDLINE via PubMed, LILACS, CINAHL, Scopus, ScienceDirect, and Web of Science) located studies that assessed the reliability and/or concordance and/or accuracy of photogrammetric protocols for evaluating cervical lordosis, compared with radiography. Articles published through April 2016 were selected. Two independent reviewers used a critical appraisal tool (QUADAS and QAREL) to assess the quality of the selected studies. Two studies were included in the review and had high levels of reliability (intraclass correlation coefficient: 0.974-0.98). Only 1 study assessed the concordance between the methods, which was calculated using Pearson's correlation coefficient. To date, the accuracy of photogrammetry has not been investigated thoroughly. We encountered no study in the literature that investigated the accuracy of photogrammetry in diagnosing hyperlordosis of cervical spine. However, both current studies report high levels of intra- and interrater reliability. To increase the level of evidence of photogrammetry in the evaluation of cervical lordosis, it is necessary to conduct further studies using a larger sample to increase the external validity of the findings. Copyright © 2018. Published by Elsevier Inc.

Effect of simulated intraoral variables on the accuracy of a photogrammetric imaging technique for complete-arch implant prostheses.

PubMed

Bratos, Manuel; Bergin, Jumping M; Rubenstein, Jeffrey E; Sorensen, John A

2018-03-17

Conventional impression techniques to obtain a definitive cast for a complete-arch implant-supported prosthesis are technique-sensitive and time-consuming. Direct optical recording with a camera could offer an alternative to conventional impression making. The purpose of this in vitro study was to test a novel intraoral image capture protocol to obtain 3-dimensional (3D) implant spatial measurement data under simulated oral conditions of vertical opening and lip retraction. A mannequin was assembled simulating the intraoral conditions of a patient having an edentulous mandible with 5 interforaminal implants. Simulated mouth openings with 2 interincisal openings (35 mm and 55 mm) and 3 lip retractions (55 mm, 75 mm, and 85 mm) were evaluated to record the implant positions. The 3D spatial orientations of implant replicas embedded in the reference model were measured using a coordinate measuring machine (CMM) (control). Five definitive casts were made with a splinted conventional impression technique of the reference model. The positions of the implant replicas for each of the 5 casts were measured with a Nobel Procera Scanner (conventional digital method). For the prototype, optical targets were secured to the implant replicas, and 3 sets of 12 images each were recorded for the photogrammetric process of 6 groups of retractions and openings using a digital camera and a standardized image capture protocol. Dimensional data were imported into photogrammetry software (photogrammetry method). The calculated and/or measured precision and accuracy of the implant positions in 3D space for the 6 groups were compared with 1-way ANOVA with an F-test (α=.05). The precision (standard error [SE] of measurement) for CMM was 3.9 μm (95% confidence interval [CI] 2.7 to 7.1 μm). For the conventional impression method, the SE of measurement was 17.2 μm (95% CI 10.3 to 49.4 μm). For photogrammetry, a grand mean was calculated for groups MinR-AvgO, MinR-MaxO, AvgR-AvgO, and MaxR-AvgO obtaining a value of 26.8 μm (95% CI 18.1 to 51.4 μm). The overall linear measurement error for accurately locating the top center points (TCP) followed a similar pattern as for precision. CMM (coordinate measurement machine) measurement represents the nonclinical gold standard, with an average error TCP distance of 4.6 μm (95% CI 3.5 to 6 μm). All photogrammetry groups presented an accuracy that ranged from 63 μm (SD 17.6) to 47 μm (SD 9.2). The grand mean of accuracy was calculated as 55.2 μm (95% CI 8.8 to 130.8 μm). The CMM group (control) demonstrated the highest levels of accuracy and precision. Most of the groups with the photogrammetric method were statistically similar to the conventional group except for groups AvgR-MaxO and MaxR-MaxO, which represented maximum opening with average retraction and maximum opening with maximum retraction. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Mapping topographic plant location properties using a dense matching approach

NASA Astrophysics Data System (ADS)

Niederheiser, Robert; Rutzinger, Martin; Lamprecht, Andrea; Bardy-Durchhalter, Manfred; Pauli, Harald; Winkler, Manuela

2017-04-01

Within the project MEDIALPS (Disentangling anthropogenic drivers of climate change impacts on alpine plant species: Alps vs. Mediterranean mountains) six regions in Alpine and in Mediterranean mountain regions are investigated to assess how plant species respond to climate change. The project is embedded in the Global Observation Research Initiative in Alpine Environments (GLORIA), which is a well-established global monitoring initiative for systematic observation of changes in the plant species composition and soil temperature on mountain summits worldwide to discern accelerating climate change pressures on these fragile alpine ecosystems. Close-range sensing techniques such as terrestrial photogrammetry are well suited for mapping terrain topography of small areas with high resolution. Lightweight equipment, flexible positioning for image acquisition in the field, and independence on weather conditions (i.e. wind) make this a feasible method for in-situ data collection. New developments of dense matching approaches allow high quality 3D terrain mapping with less requirements for field set-up. However, challenges occur in post-processing and required data storage if many sites have to be mapped. Within MEDIALPS dense matching is used for mapping high resolution topography for 284 3x3 meter plots deriving information on vegetation coverage, roughness, slope, aspect and modelled solar radiation. This information helps identifying types of topography-dependent ecological growing conditions and evaluating the potential for existing refugial locations for specific plant species under climate change. This research is conducted within the project MEDIALPS - Disentangling anthropogenic drivers of climate change impacts on alpine plant species: Alps vs. Mediterranean mountains funded by the Earth System Sciences Programme of the Austrian Academy of Sciences.

From Survey to FEM Analysis for Documentation of Built Heritage: the Case Study of Villa Revedin-Bolasco

NASA Astrophysics Data System (ADS)

Guarnieri, A.; Fissore, F.; Masiero, A.; Di Donna, A.; Coppa, U.; Vettore, A.

2017-05-01

In the last decade advances in the fields of close-range photogrammetry, terrestrial laser scanning (TLS) and computer vision (CV) have enabled to collect different kind of information about a Cultural Heritage objects and to carry out highly accurate 3D models. Additionally, the integration between laser scanning technology and Finite Element Analysis (FEA) is gaining particular interest in recent years for structural analysis of built heritage, since the increasing computational capabilities allow to manipulate large datasets. In this note we illustrate the approach adopted for surveying, 3D modeling and structural analysis of Villa Revedin-Bolasco, a magnificent historical building located in the small walled town of Castelfranco Veneto, in northern Italy. In 2012 CIRGEO was charged by the University of Padova to carry out a survey of the Villa and Park, as preliminary step for subsequent restoration works. The inner geometry of the Villa was captured with two Leica Disto D3a BT hand-held laser meters, while the outer walls of the building were surveyed with a Leica C10 and a Faro Focus 3D 120 terrestrial laser scanners. Ancillary GNSS measurements were also collected for 3D laser model georeferencing. A solid model was then generated from the laser global point cloud in Rhinoceros software, and portion of it was used for simulation in a Finite Element Analysis (FEA). In the paper we discuss in detail all the steps and challenges addressed and solutions adopted concerning the survey, solid modeling and FEA from laser scanning data of the historical complex of Villa Revedin-Bolasco.

Concept and Practice of Teaching Technical University Students to Modern Technologies of 3d Data Acquisition and Processing: a Case Study of Close-Range Photogrammetry and Terrestrial Laser Scanning

NASA Astrophysics Data System (ADS)

Kravchenko, Iulia; Luhmann, Thomas; Shults, Roman

2016-06-01

For the preparation of modern specialists in the acquisition and processing of three-dimensional data, a broad and detailed study of related modern methods and technologies is necessary. One of the most progressive and effective methods of acquisition and analyzing spatial data is terrestrial laser scanning. The study of methods and technologies for terrestrial laser scanning is of great importance not only for GIS specialists, but also for surveying engineers who make decisions in traditional engineering tasks (monitoring, executive surveys, etc.). The understanding and formation of the right approach in preparing new professionals need to develop a modern and variable educational program. This educational program must provide effective practical and laboratory work and the student's coursework. The resulting knowledge of the study should form the basis for practical or research of young engineers. In 2014, the Institute of Applied Sciences (Jade University Oldenburg, Germany) and Kyiv National University of Construction and Architecture (Kiev, Ukraine) had launched a joint educational project for the introduction of terrestrial laser scanning technology for collection and processing of spatial data. As a result of this project practical recommendations have been developed for the organization of educational processes in the use of terrestrial laser scanning. An advanced project-oriented educational program was developed which is presented in this paper. In order to demonstrate the effectiveness of the program a 3D model of the big and complex main campus of Kyiv National University of Construction and Architecture has been generated.

Photogrammetry for documentation of vehicle deformations--a tool in a system for advanced accident data collection.

PubMed

Kullgren, A; Lie, A; Tingvall, C

1994-02-01

Vehicle deformations are important sources for information about the performance of safety systems. Photogrammetry has developed vastly under recent years. In this study modern photogrammetrical methods have been used for vehicle deformation analysis. The study describes the equipment for documentation and recording in the field (semi-metric camera), and a system for photogrammetrical measurements of the images in laboratory environment (personal computer and digitizing tablet). The material used is approximately 500 collected and measured cases. The study shows that the reliability is high and that accuracies around 15mm can be achieved even if the equipment and routines used are relatively simple. The effects of further development using video cameras for data capture and digital images for measurements are discussed.

Utilizing Photogrammetry and Strain Gage Measurement to Characterize Pressurization of an Inflatable Module

NASA Technical Reports Server (NTRS)

Valle, Gerard D.; Selig, Molly; Litteken, Doug; Oliveras, Ovidio

2012-01-01

This paper documents the integration of a large hatch penetration into an inflatable module. This paper also documents the comparison of analytical load predictions with measured results utilizing strain measurement. Strain was measured by utilizing photogrammetric measurement and through measurement obtained from strain gages mounted to selected clevises that interface with the structural webbings. Bench testing showed good correlation between strain measurement obtained from an extensometer and photogrammetric measurement especially after the fabric has transitioned through the low load/high strain region of the curve. Test results for the full-scale torus showed mixed results in the lower load and thus lower strain regions. Overall strain, and thus load, measured by strain gages and photogrammetry tracked fairly well with analytical predictions. Methods and areas of improvements are discussed.

Uav Photgrammetric Workflows: a best Practice Guideline

NASA Astrophysics Data System (ADS)

Federman, A.; Santana Quintero, M.; Kretz, S.; Gregg, J.; Lengies, M.; Ouimet, C.; Laliberte, J.

2017-08-01

The increasing commercialization of unmanned aerial vehicles (UAVs) has opened the possibility of performing low-cost aerial image acquisition for the documentation of cultural heritage sites through UAV photogrammetry. The flying of UAVs in Canada is regulated through Transport Canada and requires a Special Flight Operations Certificate (SFOC) in order to fly. Various image acquisition techniques have been explored in this review, as well as well software used to register the data. A general workflow procedure has been formulated based off of the literature reviewed. A case study example of using UAV photogrammetry at Prince of Wales Fort is discussed, specifically in relation to the data acquisition and processing. Some gaps in the literature reviewed highlight the need for streamlining the SFOC application process, and incorporating UAVs into cultural heritage documentation courses.

Photogrammetry experiments with a model eye.

PubMed Central

Rosenthal, A R; Falconer, D G; Pieper, I

1980-01-01

Digital photogrammetry was performed on stereophotographs of the optic nerve head of a modified Zeiss model eye in which optic cups of varying depths could be simulated. Experiments were undertaken to determine the impact of both photographic and ocular variables on the photogrammetric measurements of cup depth. The photogrammetric procedure tolerates refocusing, repositioning, and realignment as well as small variations in the geometric position of the camera. Progressive underestimation of cup depth was observed with increasing myopia, while progressive overestimation was noted with increasing hyperopia. High cylindrical errors at axis 90 degrees led to significant errors in cup depth estimates, while high cylindrical errors at axis 180 degrees did not materially affect the accuracy of the analysis. Finally, cup depths were seriously underestimated when the pupil diameter was less than 5.0 mm. Images PMID:7448139

Classification of Aerial Photogrammetric 3d Point Clouds

NASA Astrophysics Data System (ADS)

Becker, C.; Häni, N.; Rosinskaya, E.; d'Angelo, E.; Strecha, C.

2017-05-01

We present a powerful method to extract per-point semantic class labels from aerial photogrammetry data. Labelling this kind of data is important for tasks such as environmental modelling, object classification and scene understanding. Unlike previous point cloud classification methods that rely exclusively on geometric features, we show that incorporating color information yields a significant increase in accuracy in detecting semantic classes. We test our classification method on three real-world photogrammetry datasets that were generated with Pix4Dmapper Pro, and with varying point densities. We show that off-the-shelf machine learning techniques coupled with our new features allow us to train highly accurate classifiers that generalize well to unseen data, processing point clouds containing 10 million points in less than 3 minutes on a desktop computer.

The Florence Baptistery: 3-D Survey as a Knowledge Tool for Historical and Structural Investigations

NASA Astrophysics Data System (ADS)

Tucci, G.; Bonora, V.; Fiorini, L.; Conti, A.

2016-06-01

The Baptistery of San Giovanni is one of the most important pieces of architecture in Florence. It is an octagonal building, encrusted with marble both internally and externally (including the pyramidal roof) and covered inside by a magnificent dome with sparkling gold mosaics. During Dante's time, it appeared much older than the other monuments, so its origins were considered as hailing straight from Florence's most remote and mythical history. Even though we have much more data now, scholars still disagree over the interpretations on the origin and construction sequence of the monument. Survey has always been considered a main instrument for understanding historical architecture, mostly from constructional and structural points of view. During the last century, the Baptistery was surveyed using both traditional techniques and the most up-to-date instruments available at the time, such as topography, close-range photogrammetry and laser scanning. So, a review of those early applications, even if partial or isolated, can significantly attest to the state of the art and evolution of survey techniques. During recent years, the Opera di Santa Maria del Fiore promoted new research and a wide range of diagnostic investigations aimed at acquiring greater knowledge of the monument in anticipation of the cleaning and restoration of the outer wall surfaces during 2015. Among this research, GeCo Lab carried out a new systematic and complete laser scanner survey of the whole Baptistery, acquiring data for the more inaccessible parts that were given little attention during other survey campaigns. First of all, the paper analyses recent contributions given by instrumental surveys in advancing knowledge of the building, with references to the cutting-edge techniques and measurement tools used at the time. Then, it describes the new survey campaign, illustrating the approach followed in the planning, data acquisition and data elaboration phases; finally, it gives examples of some interpretations of the structure stemming from the new acquisitions.

3D Surface Temperature Measurement of Plant Canopies Using Photogrammetry Techniques From A UAV.

NASA Astrophysics Data System (ADS)

Irvine, M.; Lagouarde, J. P.

2017-12-01

Surface temperature of plant canopies and within canopies results from the coupling of radiative and energy exchanges processes which govern the fluxes at the interface soil-plant-atmosphere. As a key parameter, surface temperature permits the estimation of canopy exchanges using processes based modeling methods. However detailed 3D surface temperature measurements or even profile surface temperature measurements are rarely made as they have inherent difficulties. Such measurements would greatly improve multi-level canopy models such as NOAH (Chen and Dudhia 2001) or MuSICA (Ogée and Brunet 2002, Ogée et al 2003) where key surface temperature estimations, at present, are not tested. Additionally, at larger scales, canopy structure greatly influences satellite based surface temperature measurements as the structure impacts the observations which are intrinsically made at varying satellite viewing angles and solar heights. In order to account for these differences, again accurate modeling is required such as through the above mentioned multi-layer models or with several source type models such as SCOPE (Van der Tol 2009) in order to standardize observations. As before, in order to validate these models, detailed field observations are required. With the need for detailed surface temperature observations in mind we have planned a series of experiments over non-dense plant canopies to investigate the use of photogrammetry techniques. Photogrammetry is normally used for visible wavelengths to produce 3D images using cloud point reconstruction of aerial images (for example Dandois and Ellis, 2010, 2013 over a forest). From these cloud point models it should be possible to establish 3D plant surface temperature images when using thermal infrared array sensors. In order to do this our experiments are based on the use of a thermal Infrared camera embarked on a UAV. We adapt standard photogrammetry to account for limits imposed by thermal imaginary, especially the low image resolution compared with standard RGB sensors. At the session B081, we intend to present first results of our thermal photogrammetric experiments with 3D surface temperature plots in order to discuss and adapt our methods to the modelling community's needs.

A robust real-time surface reconstruction method on point clouds captured from a 3D surface photogrammetry system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Wenyang; Cheung, Yam; Sawant, Amit

2016-05-15

Purpose: To develop a robust and real-time surface reconstruction method on point clouds captured from a 3D surface photogrammetry system. Methods: The authors have developed a robust and fast surface reconstruction method on point clouds acquired by the photogrammetry system, without explicitly solving the partial differential equation required by a typical variational approach. Taking advantage of the overcomplete nature of the acquired point clouds, their method solves and propagates a sparse linear relationship from the point cloud manifold to the surface manifold, assuming both manifolds share similar local geometry. With relatively consistent point cloud acquisitions, the authors propose a sparsemore » regression (SR) model to directly approximate the target point cloud as a sparse linear combination from the training set, assuming that the point correspondences built by the iterative closest point (ICP) is reasonably accurate and have residual errors following a Gaussian distribution. To accommodate changing noise levels and/or presence of inconsistent occlusions during the acquisition, the authors further propose a modified sparse regression (MSR) model to model the potentially large and sparse error built by ICP with a Laplacian prior. The authors evaluated the proposed method on both clinical point clouds acquired under consistent acquisition conditions and on point clouds with inconsistent occlusions. The authors quantitatively evaluated the reconstruction performance with respect to root-mean-squared-error, by comparing its reconstruction results against that from the variational method. Results: On clinical point clouds, both the SR and MSR models have achieved sub-millimeter reconstruction accuracy and reduced the reconstruction time by two orders of magnitude to a subsecond reconstruction time. On point clouds with inconsistent occlusions, the MSR model has demonstrated its advantage in achieving consistent and robust performance despite the introduced occlusions. Conclusions: The authors have developed a fast and robust surface reconstruction method on point clouds captured from a 3D surface photogrammetry system, with demonstrated sub-millimeter reconstruction accuracy and subsecond reconstruction time. It is suitable for real-time motion tracking in radiotherapy, with clear surface structures for better quantifications.« less

Catchment-scale snow depth monitoring with balloon photogrammetry

NASA Astrophysics Data System (ADS)

Durand, M. T.; Li, D.; Wigmore, O.; Vanderjagt, B. J.; Molotch, N. P.; Bales, R. C.

2016-12-01

Field campaigns and permanent in-situ facilities provide extensive measurements of snowpack properties at catchment (or smaller) scales, and have consistently improved our understanding of snow processes and the estimation of snow water resources. However, snow depth, one of the most important snow states, has been measured almost entirely with discrete point-scale samplings in field measurements; spatiotemporally continuous snow depth measurements are nearly nonexistent, mainly due to the high cost of airborne flights and the ban of Unmanned Aerial Systems in many areas (e.g. in all the national parks). In this study, we estimate spatially continuous snow depth from photogrammetric reconstruction of aerial photos taken from a weather balloon. The study was conducted in a 0.2 km2 watershed in Wolverton, Sequoia National Park, California. We tied a point-and-shoot camera on a helium-inflated weather balloon to take aerial images; the camera was scripted to automatically capture images every 3 seconds and to record the camera position and orientation at the imaging times using a built-in GPS. With the 2D images of the snow-covered ground and the camera position and orientation data, the 3D coordinates of the snow surface were reconstructed at 10 cm resolution using photogrammetry software PhotoScan. Similar measurements were taken for the snow-free ground after snowmelt, and the snow depth was estimated from the difference between the snow-on and snow-off measurements. Comparing the photogrammetric-estimated snow depths with the 32 manually measured depths, taken at the same time as the snow-on balloon flight, we find the RMSE of the photogrammetric snow depth is 7 cm, which is 2% of the long-term peak snow depth in the study area. This study suggests that the balloon photogrammetry is a repeatable, economical, simple, and environmental-friendly method to continuously monitor snow at small-scales. Spatiotemporally continuous snow depth could be regularly measured in future field measurements to supplement traditional snow property observations. In addition, since the process of collecting and processing balloon photogrammetry data is straightforward, the photogrammetric snow depth could be shared with the public in real time using our cloud platform that is currently under development.

A robust real-time surface reconstruction method on point clouds captured from a 3D surface photogrammetry system.

PubMed

Liu, Wenyang; Cheung, Yam; Sawant, Amit; Ruan, Dan

2016-05-01

To develop a robust and real-time surface reconstruction method on point clouds captured from a 3D surface photogrammetry system. The authors have developed a robust and fast surface reconstruction method on point clouds acquired by the photogrammetry system, without explicitly solving the partial differential equation required by a typical variational approach. Taking advantage of the overcomplete nature of the acquired point clouds, their method solves and propagates a sparse linear relationship from the point cloud manifold to the surface manifold, assuming both manifolds share similar local geometry. With relatively consistent point cloud acquisitions, the authors propose a sparse regression (SR) model to directly approximate the target point cloud as a sparse linear combination from the training set, assuming that the point correspondences built by the iterative closest point (ICP) is reasonably accurate and have residual errors following a Gaussian distribution. To accommodate changing noise levels and/or presence of inconsistent occlusions during the acquisition, the authors further propose a modified sparse regression (MSR) model to model the potentially large and sparse error built by ICP with a Laplacian prior. The authors evaluated the proposed method on both clinical point clouds acquired under consistent acquisition conditions and on point clouds with inconsistent occlusions. The authors quantitatively evaluated the reconstruction performance with respect to root-mean-squared-error, by comparing its reconstruction results against that from the variational method. On clinical point clouds, both the SR and MSR models have achieved sub-millimeter reconstruction accuracy and reduced the reconstruction time by two orders of magnitude to a subsecond reconstruction time. On point clouds with inconsistent occlusions, the MSR model has demonstrated its advantage in achieving consistent and robust performance despite the introduced occlusions. The authors have developed a fast and robust surface reconstruction method on point clouds captured from a 3D surface photogrammetry system, with demonstrated sub-millimeter reconstruction accuracy and subsecond reconstruction time. It is suitable for real-time motion tracking in radiotherapy, with clear surface structures for better quantifications.

A robust real-time surface reconstruction method on point clouds captured from a 3D surface photogrammetry system

PubMed Central

Liu, Wenyang; Cheung, Yam; Sawant, Amit; Ruan, Dan

2016-01-01

Purpose: To develop a robust and real-time surface reconstruction method on point clouds captured from a 3D surface photogrammetry system. Methods: The authors have developed a robust and fast surface reconstruction method on point clouds acquired by the photogrammetry system, without explicitly solving the partial differential equation required by a typical variational approach. Taking advantage of the overcomplete nature of the acquired point clouds, their method solves and propagates a sparse linear relationship from the point cloud manifold to the surface manifold, assuming both manifolds share similar local geometry. With relatively consistent point cloud acquisitions, the authors propose a sparse regression (SR) model to directly approximate the target point cloud as a sparse linear combination from the training set, assuming that the point correspondences built by the iterative closest point (ICP) is reasonably accurate and have residual errors following a Gaussian distribution. To accommodate changing noise levels and/or presence of inconsistent occlusions during the acquisition, the authors further propose a modified sparse regression (MSR) model to model the potentially large and sparse error built by ICP with a Laplacian prior. The authors evaluated the proposed method on both clinical point clouds acquired under consistent acquisition conditions and on point clouds with inconsistent occlusions. The authors quantitatively evaluated the reconstruction performance with respect to root-mean-squared-error, by comparing its reconstruction results against that from the variational method. Results: On clinical point clouds, both the SR and MSR models have achieved sub-millimeter reconstruction accuracy and reduced the reconstruction time by two orders of magnitude to a subsecond reconstruction time. On point clouds with inconsistent occlusions, the MSR model has demonstrated its advantage in achieving consistent and robust performance despite the introduced occlusions. Conclusions: The authors have developed a fast and robust surface reconstruction method on point clouds captured from a 3D surface photogrammetry system, with demonstrated sub-millimeter reconstruction accuracy and subsecond reconstruction time. It is suitable for real-time motion tracking in radiotherapy, with clear surface structures for better quantifications. PMID:27147347

An evaluation of three-dimensional photogrammetric and morphometric techniques for estimating volume and mass in Weddell seals Leptonychotes weddellii

PubMed Central

Ruscher-Hill, Brandi; Kirkham, Amy L.; Burns, Jennifer M.

2018-01-01

Body mass dynamics of animals can indicate critical associations between extrinsic factors and population vital rates. Photogrammetry can be used to estimate mass of individuals in species whose life histories make it logistically difficult to obtain direct body mass measurements. Such studies typically use equations to relate volume estimates from photogrammetry to mass; however, most fail to identify the sources of error between the estimated and actual mass. Our objective was to identify the sources of error that prevent photogrammetric mass estimation from directly predicting actual mass, and develop a methodology to correct this issue. To do this, we obtained mass, body measurements, and scaled photos for 56 sedated Weddell seals (Leptonychotes weddellii). After creating a three-dimensional silhouette in the image processing program PhotoModeler Pro, we used horizontal scale bars to define the ground plane, then removed the below-ground portion of the animal’s estimated silhouette. We then re-calculated body volume and applied an expected density to estimate animal mass. We compared the body mass estimates derived from this silhouette slice method with estimates derived from two other published methodologies: body mass calculated using photogrammetry coupled with a species-specific correction factor, and estimates using elliptical cones and measured tissue densities. The estimated mass values (mean ± standard deviation 345±71 kg for correction equation, 346±75 kg for silhouette slice, 343±76 kg for cones) were not statistically distinguishable from each other or from actual mass (346±73 kg) (ANOVA with Tukey HSD post-hoc, p>0.05 for all pairwise comparisons). We conclude that volume overestimates from photogrammetry are likely due to the inability of photo modeling software to properly render the ventral surface of the animal where it contacts the ground. Due to logistical differences between the “correction equation”, “silhouette slicing”, and “cones” approaches, researchers may find one technique more useful for certain study programs. In combination or exclusively, these three-dimensional mass estimation techniques have great utility in field studies with repeated measures sampling designs or where logistic constraints preclude weighing animals. PMID:29320573

Quantifying alignment effects in 3D coordinate measurement.

DOT National Transportation Integrated Search

2009-10-01

The use of fixtureless, non-contact coordinate measurement has become increasingly prevalent in manufacturing : problem solving. Manufacturers now routinely use measurement systems such as white light area scanners, photogrammetry, : laser trackers, ...

Semantic segmentation of 3D textured meshes for urban scene analysis

NASA Astrophysics Data System (ADS)

Rouhani, Mohammad; Lafarge, Florent; Alliez, Pierre

2017-01-01

Classifying 3D measurement data has become a core problem in photogrammetry and 3D computer vision, since the rise of modern multiview geometry techniques, combined with affordable range sensors. We introduce a Markov Random Field-based approach for segmenting textured meshes generated via multi-view stereo into urban classes of interest. The input mesh is first partitioned into small clusters, referred to as superfacets, from which geometric and photometric features are computed. A random forest is then trained to predict the class of each superfacet as well as its similarity with the neighboring superfacets. Similarity is used to assign the weights of the Markov Random Field pairwise-potential and to account for contextual information between the classes. The experimental results illustrate the efficacy and accuracy of the proposed framework.

Uses of software in digital image analysis: a forensic report

NASA Astrophysics Data System (ADS)

Sharma, Mukesh; Jha, Shailendra

2010-02-01

Forensic image analysis is required an expertise to interpret the content of an image or the image itself in legal matters. Major sub-disciplines of forensic image analysis with law enforcement applications include photo-grammetry, photographic comparison, content analysis and image authentication. It has wide applications in forensic science range from documenting crime scenes to enhancing faint or indistinct patterns such as partial fingerprints. The process of forensic image analysis can involve several different tasks, regardless of the type of image analysis performed. Through this paper authors have tried to explain these tasks, which are described in to three categories: Image Compression, Image Enhancement & Restoration and Measurement Extraction. With the help of examples like signature comparison, counterfeit currency comparison and foot-wear sole impression using the software Canvas and Corel Draw.

78 FR 30872 - Marine Mammals; File Nos. 14451, 14353, and 13846

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-23

... recording, and underwater photo/videography. Suction cup tags are deployed on humpback whales. Minke whales..., collection of sloughed skin, photogrammetry, biopsy sampling, playback experiments, and/or suction cup and...

77 FR 5062 - Notice of Intent To Grant a Partially Exclusive License

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-01

... No. 13/ 105,004 entitled ``Photogrammetry System and Method for Determining Relative Motion Between Two Bodies,'' to Magic Leap, Incorporated having its principal place of business in Hollywood, Florida...

Topographic Mapmaking.

ERIC Educational Resources Information Center

Meunier, Tony K.

1980-01-01

The making of topographic maps is described as a sequence of the following steps: establishment of control, photogrammetry and field operations, annotation of photographs, stereoplatting, editing, preparation of color-separation plates, and printing. Precise standards are emphasized. (Author/SA)

Creep Burst Testing of a Woven Inflatable Module

NASA Technical Reports Server (NTRS)

Selig, Molly M.; Valle, Gerard D.; James, George H.; Oliveras, Ovidio M.; Jones, Thomas C.; Doggett, William R.

2015-01-01

A woven Vectran inflatable module 88 inches in diameter and 10 feet long was tested at the NASA Johnson Space Center until failure from creep. The module was pressurized pneumatically to an internal pressure of 145 psig, and was held at pressure until burst. The external environment remained at standard atmospheric temperature and pressure. The module burst occurred after 49 minutes at the target pressure. The test article pressure and temperature were monitored, and video footage of the burst was captured at 60 FPS. Photogrammetry was used to obtain strain measurements of some of the webbing. Accelerometers on the test article measured the dynamic response. This paper discusses the test article, test setup, predictions, observations, photogrammetry technique and strain results, structural dynamics methods and quick-look results, and a comparison of the module level creep behavior to the strap level creep behavior.

Orion Ground Test Article Water Impact Tests: Photogrammetric Evaluation of Impact Conditions

NASA Technical Reports Server (NTRS)

Vassilakos, Gregory J.; Mark, Stephen D.

2018-01-01

The Ground Test Article (GTA) is an early production version of the Orion Crew Module (CM). The structural design of the Orion CM is being developed based on LS-DYNA water landing simulations. As part of the process of confirming the accuracy of LS-DYNA water landing simulations, the GTA water impact test series was conducted at NASA Langley Research Center (LaRC) to gather data for comparison with simulations. The simulation of the GTA water impact tests requires the accurate determination of the impact conditions. To accomplish this, the GTA was outfitted with an array of photogrammetry targets. The photogrammetry system utilizes images from two cameras with a specialized tracking software to determine time histories for the 3-D coordinates of each target. The impact conditions can then be determined from the target location data.

Uav Photogrammetry: a Practical Solution for Challenging Mapping Projects

NASA Astrophysics Data System (ADS)

Saadatseresht, M.; Hashempour, A. H.; Hasanlou, M.

2015-12-01

We have observed huge attentions to application of unmanned aerial vehicle (UAV) in aerial mapping since a decade ago. Though, it has several advantages for handling time/cost/quality issues, there are a dozen of challenges in working with UAVs. In this paper, we; as the Robotic Photogrammetry Research Group (RPRG), will firstly review these challenges then show its advantages in three special practical projects. For each project, we will share our experiences through description of the UAV specifications, flight settings and processing steps. At the end, we will illustrate final result of each project and show how this technology could make unbelievable benefits to clients including 3D city realistic model in decimetre level, ultra high quality map production in several centimetre level, and accessing to a high risk and rough relief area for mapping aims.

Computer Aided Teaching in Photogrammetry, Remote Sensing, and Geomatics - A Status Review

NASA Astrophysics Data System (ADS)

Vyas, A.; Koenig, G.

2014-04-01

Education and training play vital role in the utilization of the technology. Shared and coordinated knowledge that geospatial technology and GIS deliver provides a deeper understanding of our present and will also help to better understand our future development. But it is not enough to explain new technological developments during congresses or workshops; it is also necessary to promote these new ideas and to distribute the knowledge by applying new learning strategies. This paper will review the status of computer aided teaching advances during the last decade, with a particular emphasis on photogrammetry, remote sensing, and geomatics. Some best practise examples will be presented featuring prominently recent Massive Open Online Courses (MOOCs) related to our fields. The consideration of mainly free online learning resources will include a commentary on quality and perceived effectiveness.

Accuracy Assessment of a Canal-Tunnel 3d Model by Comparing Photogrammetry and Laserscanning Recording Techniques

NASA Astrophysics Data System (ADS)

Charbonnier, P.; Chavant, P.; Foucher, P.; Muzet, V.; Prybyla, D.; Perrin, T.; Grussenmeyer, P.; Guillemin, S.

2013-07-01

With recent developments in the field of technology and computer science, conventional methods are being supplanted by laser scanning and digital photogrammetry. These two different surveying techniques generate 3-D models of real world objects or structures. In this paper, we consider the application of terrestrial Laser scanning (TLS) and photogrammetry to the surveying of canal tunnels. The inspection of such structures requires time, safe access, specific processing and professional operators. Therefore, a French partnership proposes to develop a dedicated equipment based on image processing for visual inspection of canal tunnels. A 3D model of the vault and side walls of the tunnel is constructed from images recorded onboard a boat moving inside the tunnel. To assess the accuracy of this photogrammetric model (PM), a reference model is build using static TLS. We here address the problem comparing the resulting point clouds. Difficulties arise because of the highly differentiated acquisition processes, which result in very different point densities. We propose a new tool, designed to compare differences between pairs of point cloud or surfaces (triangulated meshes). Moreover, dealing with huge datasets requires the implementation of appropriate structures and algorithms. Several techniques are presented : point-to-point, cloud-to-cloud and cloud-to-mesh. In addition farthest point resampling, octree structure and Hausdorff distance are adopted and described. Experimental results are shown for a 475 m long canal tunnel located in France.

Monoscopic photogrammetry to obtain 3D models by a mobile device: a method for making facial prostheses.

PubMed

Salazar-Gamarra, Rodrigo; Seelaus, Rosemary; da Silva, Jorge Vicente Lopes; da Silva, Airton Moreira; Dib, Luciano Lauria

2016-05-25

The aim of this study is to present the development of a new technique to obtain 3D models using photogrammetry by a mobile device and free software, as a method for making digital facial impressions of patients with maxillofacial defects for the final purpose of 3D printing of facial prostheses. With the use of a mobile device, free software and a photo capture protocol, 2D captures of the anatomy of a patient with a facial defect were transformed into a 3D model. The resultant digital models were evaluated for visual and technical integrity. The technical process and resultant models were described and analyzed for technical and clinical usability. Generating 3D models to make digital face impressions was possible by the use of photogrammetry with photos taken by a mobile device. The facial anatomy of the patient was reproduced by a *.3dp and a *.stl file with no major irregularities. 3D printing was possible. An alternative method for capturing facial anatomy is possible using a mobile device for the purpose of obtaining and designing 3D models for facial rehabilitation. Further studies must be realized to compare 3D modeling among different techniques and systems. Free software and low cost equipment could be a feasible solution to obtain 3D models for making digital face impressions for maxillofacial prostheses, improving access for clinical centers that do not have high cost technology considered as a prior acquisition.

Photogrammetry and ballistic analysis of a high-flying projectile in the STS-124 space shuttle launch

NASA Astrophysics Data System (ADS)

Metzger, Philip T.; Lane, John E.; Carilli, Robert A.; Long, Jason M.; Shawn, Kathy L.

2010-07-01

A method combining photogrammetry with ballistic analysis is demonstrated to identify flying debris in a rocket launch environment. Debris traveling near the STS-124 Space Shuttle was captured on cameras viewing the launch pad within the first few seconds after launch. One particular piece of debris caught the attention of investigators studying the release of flame trench fire bricks because its high trajectory could indicate a flight risk to the Space Shuttle. Digitized images from two pad perimeter high-speed 16-mm film cameras were processed using photogrammetry software based on a multi-parameter optimization technique. Reference points in the image were found from 3D CAD models of the launch pad and from surveyed points on the pad. The three-dimensional reference points were matched to the equivalent two-dimensional camera projections by optimizing the camera model parameters using a gradient search optimization technique. Using this method of solving the triangulation problem, the xyz position of the object's path relative to the reference point coordinate system was found for every set of synchronized images. This trajectory was then compared to a predicted trajectory while performing regression analysis on the ballistic coefficient and other parameters. This identified, with a high degree of confidence, the object's material density and thus its probable origin within the launch pad environment. Future extensions of this methodology may make it possible to diagnose the underlying causes of debris-releasing events in near-real time, thus improving flight safety.

Wetland Assessment Using Unmanned Aerial Vehicle (uav) Photogrammetry

NASA Astrophysics Data System (ADS)

Boon, M. A.; Greenfield, R.; Tesfamichael, S.

2016-06-01

The use of Unmanned Arial Vehicle (UAV) photogrammetry is a valuable tool to enhance our understanding of wetlands. Accurate planning derived from this technological advancement allows for more effective management and conservation of wetland areas. This paper presents results of a study that aimed at investigating the use of UAV photogrammetry as a tool to enhance the assessment of wetland ecosystems. The UAV images were collected during a single flight within 2½ hours over a 100 ha area at the Kameelzynkraal farm, Gauteng Province, South Africa. An AKS Y-6 MKII multi-rotor UAV and a digital camera on a motion compensated gimbal mount were utilised for the survey. Twenty ground control points (GCPs) were surveyed using a Trimble GPS to achieve geometrical precision and georeferencing accuracy. Structure-from-Motion (SfM) computer vision techniques were used to derive ultra-high resolution point clouds, orthophotos and 3D models from the multi-view photos. The geometric accuracy of the data based on the 20 GCP's were 0.018 m for the overall, 0.0025 m for the vertical root mean squared error (RMSE) and an over all root mean square reprojection error of 0.18 pixel. The UAV products were then edited and subsequently analysed, interpreted and key attributes extracted using a selection of tools/ software applications to enhance the wetland assessment. The results exceeded our expectations and provided a valuable and accurate enhancement to the wetland delineation, classification and health assessment which even with detailed field studies would have been difficult to achieve.

Data Provenance in Photogrammetry Through Documentation Protocols

NASA Astrophysics Data System (ADS)

Carboni, N.; Bruseker, G.; Guillem, A.; Bellido Castañeda, D.; Coughenour, C.; Domajnko, M.; de Kramer, M.; Ramos Calles, M. M.; Stathopoulou, E. K.; Suma, R.

2016-06-01

Documenting the relevant aspects in digitisation processes such as photogrammetry in order to provide a robust provenance for their products continues to present a challenge. The creation of a product that can be re-used scientifically requires a framework for consistent, standardised documentation of the entire digitisation pipeline. This article provides an analysis of the problems inherent to such goals and presents a series of protocols to document the various steps of a photogrammetric workflow. We propose this pipeline, with descriptors to track all phases of digital product creation in order to assure data provenance and enable the validation of the operations from an analytic and production perspective. The approach aims to support adopters of the workflow to define procedures with a long term perspective. The conceptual schema we present is founded on an analysis of information and actor exchanges in the digitisation process. The metadata were defined through the synthesis of previous proposals in this area and were tested on a case study. We performed the digitisation of a set of cultural heritage artefacts from an Iron Age burial in Ilmendorf, Germany. The objects were captured and processed using different techniques, including a comparison of different imaging tools and algorithms. This augmented the complexity of the process allowing us to test the flexibility of the schema for documenting complex scenarios. Although we have only presented a photogrammetry digitisation scenario, we claim that our schema is easily applicable to a multitude of 3D documentation processes.

3D documenatation of the petalaindera: digital heritage preservation methods using 3D laser scanner and photogrammetry

NASA Astrophysics Data System (ADS)

Sharif, Harlina Md; Hazumi, Hazman; Hafizuddin Meli, Rafiq

2018-01-01

3D imaging technologies have undergone massive revolution in recent years. Despite this rapid development, documentation of 3D cultural assets in Malaysia is still very much reliant upon conventional techniques such as measured drawings and manual photogrammetry. There is very little progress towards exploring new methods or advanced technologies to convert 3D cultural assets into 3D visual representation and visualization models that are easily accessible for information sharing. In recent years, however, the advent of computer vision (CV) algorithms make it possible to reconstruct 3D geometry of objects by using image sequences from digital cameras, which are then processed by web services and freeware applications. This paper presents a completed stage of an exploratory study that investigates the potentials of using CV automated image-based open-source software and web services to reconstruct and replicate cultural assets. By selecting an intricate wooden boat, Petalaindera, this study attempts to evaluate the efficiency of CV systems and compare it with the application of 3D laser scanning, which is known for its accuracy, efficiency and high cost. The final aim of this study is to compare the visual accuracy of 3D models generated by CV system, and 3D models produced by 3D scanning and manual photogrammetry for an intricate subject such as the Petalaindera. The final objective is to explore cost-effective methods that could provide fundamental guidelines on the best practice approach for digital heritage in Malaysia.

Photogrammetry-Based Head Digitization for Rapid and Accurate Localization of EEG Electrodes and MEG Fiducial Markers Using a Single Digital SLR Camera.

PubMed

Clausner, Tommy; Dalal, Sarang S; Crespo-García, Maité

2017-01-01

The performance of EEG source reconstruction has benefited from the increasing use of advanced head modeling techniques that take advantage of MRI together with the precise positions of the recording electrodes. The prevailing technique for registering EEG electrode coordinates involves electromagnetic digitization. However, the procedure adds several minutes to experiment preparation and typical digitizers may not be accurate enough for optimal source reconstruction performance (Dalal et al., 2014). Here, we present a rapid, accurate, and cost-effective alternative method to register EEG electrode positions, using a single digital SLR camera, photogrammetry software, and computer vision techniques implemented in our open-source toolbox, janus3D . Our approach uses photogrammetry to construct 3D models from multiple photographs of the participant's head wearing the EEG electrode cap. Electrodes are detected automatically or semi-automatically using a template. The rigid facial features from these photo-based models are then surface-matched to MRI-based head reconstructions to facilitate coregistration to MRI space. This method yields a final electrode coregistration error of 0.8 mm, while a standard technique using an electromagnetic digitizer yielded an error of 6.1 mm. The technique furthermore reduces preparation time, and could be extended to a multi-camera array, which would make the procedure virtually instantaneous. In addition to EEG, the technique could likewise capture the position of the fiducial markers used in magnetoencephalography systems to register head position.

A multi-scale approach of fluvial biogeomorphic dynamics using photogrammetry.

PubMed

Hortobágyi, Borbála; Corenblit, Dov; Vautier, Franck; Steiger, Johannes; Roussel, Erwan; Burkart, Andreas; Peiry, Jean-Luc

2017-11-01

Over the last twenty years, significant technical advances turned photogrammetry into a relevant tool for the integrated analysis of biogeomorphic cross-scale interactions within vegetated fluvial corridors, which will largely contribute to the development and improvement of self-sustainable river restoration efforts. Here, we propose a cost-effective, easily reproducible approach based on stereophotogrammetry and Structure from Motion (SfM) technique to study feedbacks between fluvial geomorphology and riparian vegetation at different nested spatiotemporal scales. We combined different photogrammetric methods and thus were able to investigate biogeomorphic feedbacks at all three spatial scales (i.e., corridor, alluvial bar and micro-site) and at three different temporal scales, i.e., present, recent past and long term evolution on a diversified riparian landscape mosaic. We evaluate the performance and the limits of photogrammetric methods by targeting a set of fundamental parameters necessary to study biogeomorphic feedbacks at each of the three nested spatial scales and, when possible, propose appropriate solutions. The RMSE varies between 0.01 and 2 m depending on spatial scale and photogrammetric methods. Despite some remaining difficulties to properly apply them with current technologies under all circumstances in fluvial biogeomorphic studies, e.g. the detection of vegetation density or landform topography under a dense vegetation canopy, we suggest that photogrammetry is a promising instrument for the quantification of biogeomorphic feedbacks at nested spatial scales within river systems and for developing appropriate river management tools and strategies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Photogrammetry of fetal breathing movements during the third trimester of pregnancy: observations in normal and abnormal pregnancies.

PubMed

Florido, J; Padilla, M C; Soto, V; Camacho, A; Moscoso, G; Navarrete, L

2008-09-01

To evaluate parameters of fetal breathing movements-displacement of the fetal abdominal wall during inspiration and expiration, time of inspiration and expiration and speed of inspiration and expiration-between 30 and 36 weeks' gestation in normal pregnancies, and in those complicated by gestational diabetes or maternal hypertension. Three categories of pregnancy were investigated: 49 were normal, 16 had pregnancy-induced diabetes and 10 were hypertensive. According to their gestational age, the patients were divided into two groups: Group A between 30 and 32 weeks' gestation and Group B between 33 and 36 weeks. Using photogrammetry and a computer-operated algorithm, six parameters of fetal breathing movements were investigated. There were significant differences in the various fetal parameters measured among the three categories of pregnant women. Up until 32 weeks of gestation, the displacements during inspiration and expiration were larger, the speeds of inspiration and expiration were higher, and the times for inspiration and expiration were shorter in the diabetic and hypertensive groups than in the normal group. In the later period, between 33 and 36 weeks, fetuses of pregnancy-induced diabetic patients showed the lowest inspiration and expiration times and the highest speeds of inspiration and expiration. Photogrammetry in conjunction with a computer-operated algorithm can be used to assess fetal breathing movements. There are significant differences in fetal breathing movements between normal pregnancies and those that are complicated by gestational diabetes or hypertension.

Photogrammetry-Based Head Digitization for Rapid and Accurate Localization of EEG Electrodes and MEG Fiducial Markers Using a Single Digital SLR Camera

PubMed Central

Clausner, Tommy; Dalal, Sarang S.; Crespo-García, Maité

2017-01-01

The performance of EEG source reconstruction has benefited from the increasing use of advanced head modeling techniques that take advantage of MRI together with the precise positions of the recording electrodes. The prevailing technique for registering EEG electrode coordinates involves electromagnetic digitization. However, the procedure adds several minutes to experiment preparation and typical digitizers may not be accurate enough for optimal source reconstruction performance (Dalal et al., 2014). Here, we present a rapid, accurate, and cost-effective alternative method to register EEG electrode positions, using a single digital SLR camera, photogrammetry software, and computer vision techniques implemented in our open-source toolbox, janus3D. Our approach uses photogrammetry to construct 3D models from multiple photographs of the participant's head wearing the EEG electrode cap. Electrodes are detected automatically or semi-automatically using a template. The rigid facial features from these photo-based models are then surface-matched to MRI-based head reconstructions to facilitate coregistration to MRI space. This method yields a final electrode coregistration error of 0.8 mm, while a standard technique using an electromagnetic digitizer yielded an error of 6.1 mm. The technique furthermore reduces preparation time, and could be extended to a multi-camera array, which would make the procedure virtually instantaneous. In addition to EEG, the technique could likewise capture the position of the fiducial markers used in magnetoencephalography systems to register head position. PMID:28559791

Photogrammetric analysis of concrete specimens and structures for condition assessment

NASA Astrophysics Data System (ADS)

D'Amico, Nicolas; Yu, Tzuyang

2016-04-01

Deterioration of civil infrastructure in America demands routine inspection and maintenance to avoid catastrophic failures from occurring. Among many other non-destructive evaluations (NDE), photogrammetry is an accessible and realistic approach used for non-destructive evaluation (NDE) of a civil infrastructure systems. The objective of this paper is to explore the capabilities of photogrammetry for locating, sizing, and analyzing the remaining capacity of a specimen or system using point cloud data. Geometric interpretations, composed from up to 70 photographs are analyzed as a mesh or point cloud models. In this case study, concrete, which exhibits a large amount of surface texture features, was thoroughly examined. These evaluative techniques discussed were applied to concrete cylinder models as well as portions of civil infrastructure including buildings, retaining walls, and bridge abutments. In this paper, the aim is to demonstrate the basic analytical functionality of photogrammetry, as well as its applicability to in-situ civil infrastructure systems. In concrete specimens defect length and location can be evaluated in a fully defined model (one with the maximum amount of correctly acquired photographs) with less than 2% error. Error was found to be inversely proportional to the number of acceptable photographs acquired, remaining significantly under 10% error for any model with enough data to render. Furthermore, volumetric stress evaluations were applied using a cross sectional evaluation technique to locate the critical area, and determine the severity of damages. Finally, findings and the accuracy of the results are discussed.

UAV photogrammetry for topographic monitoring of coastal areas

NASA Astrophysics Data System (ADS)

Gonçalves, J. A.; Henriques, R.

2015-06-01

Coastal areas suffer degradation due to the action of the sea and other natural and human-induced causes. Topographical changes in beaches and sand dunes need to be assessed, both after severe events and on a regular basis, to build models that can predict the evolution of these natural environments. This is an important application for airborne LIDAR, and conventional photogrammetry is also being used for regular monitoring programs of sensitive coastal areas. This paper analyses the use of unmanned aerial vehicles (UAV) to map and monitor sand dunes and beaches. A very light plane (SwingletCam) equipped with a very cheap, non-metric camera was used to acquire images with ground resolutions better than 5 cm. The Agisoft Photoscan software was used to orientate the images, extract point clouds, build a digital surface model and produce orthoimage mosaics. The processing, which includes automatic aerial triangulation with camera calibration and subsequent model generation, was mostly automated. To achieve the best positional accuracy for the whole process, signalised ground control points were surveyed with a differential GPS receiver. Two very sensitive test areas on the Portuguese northwest coast were analysed. Detailed DSMs were obtained with 10 cm grid spacing and vertical accuracy (RMS) ranging from 3.5 to 5.0 cm, which is very similar to the image ground resolution (3.2-4.5 cm). Where possible to assess, the planimetric accuracy of the orthoimage mosaics was found to be subpixel. Within the regular coastal monitoring programme being carried out in the region, UAVs can replace many of the conventional flights, with considerable gains in the cost of the data acquisition and without any loss in the quality of topographic and aerial imagery data.

Application of photogrammetry to the study of volcano-glacier interactions on Mount Wrangell, Alaska

NASA Technical Reports Server (NTRS)

Benson, C. S.; Follett, A. B.

1986-01-01

Most Alaskan volcanoes are glacier covered and provide excellent opportunities to study interactions between glaciers and volcanoes. The present paper is concerned with such a study, taking into account the Mt. Wrangell (4317 m) which is the northernmost active volcano (solfatara activity) on the Pacific Rim (62 deg N; 144 deg W). While the first photographs on the summit of Mt. Wrangell were published more than 75 years ago, research there began in 1953 and 1954. Satellite images reveal activity at the summit of Mt. Wrangell. However, the resolution is not sufficient for conducting important measurements regarding ice volume losses. For this reason, vertical aerial photographs of the summit were obtained, and a field trip to the summit was conducted. Aspects of photogrammetry are discussed, taking into account questions of ground control, aerial photography, topographic mapping, digital cross sections, and orthophotos.

Integration of ground-based laser scanner and aerial digital photogrammetry for topographic modelling of Vesuvio volcano

NASA Astrophysics Data System (ADS)

Pesci, Arianna; Fabris, Massimo; Conforti, Dario; Loddo, Fabiana; Baldi, Paolo; Anzidei, Marco

2007-05-01

This work deals with the integration of different surveying methodologies for the definition of very accurate Digital Terrain Models (DTM) and/or Digital Surface Models (DSM): in particular, the aerial digital photogrammetry and the terrestrial laser scanning were used to survey the Vesuvio volcano, allowing the total coverage of the internal cone and surroundings (the whole surveyed area was about 3 km × 3 km). The possibility to reach a very high precision, especially from the laser scanner data set, allowed a detailed description of the morphology of the volcano. The comparisons of models obtained in repeated surveys allow a detailed map of residuals providing a data set that can be used for detailed studies of the morphological evolution. Moreover, the reflectivity information, highly correlated to materials properties, allows for the measurement and quantification of some morphological variations in areas where structural discontinuities and displacements are present.

BIM applied in historical building documentation and refurbishing

NASA Astrophysics Data System (ADS)

Cheng, H.-M.; Yang, W.-B.; Yen, Y.-N.

2015-08-01

Historical building conservation raises two important issues which are documentation and refurbishing. For the recording and documentation, we already have developed 3d laser scanner and such photogrammetry technology those represent a freeze object of virtual reality by digital documentation. On the other hand, the refurbished engineering of historic building is a challenge for conservation heritage which are not only reconstructing the damage part but also restoring tangible cultural heritage. 3D digital cultural heritage models has become a topic of great interest in recent years. One reason for this is the more widespread use of laser scanning and photogrammetry for recording cultural heritage sites. These technologies have made it possible to efficiently and accurately record complex structures remotely that would not have been possible with previous survey methods. In addition to these developments, digital information systems are evolving for the presentation, analysis and archival of heritage documentation.

Effects of Notch Misalignment and Tip Radius on Displacement Field in V-Notch Rail Shear Test as Determined by Photogrammetry

NASA Technical Reports Server (NTRS)

Hill, Charles S.; Oliveras, Ovidio M.

2011-01-01

Evolution of the 3D strain field during ASTM-D-7078 v-notch rail shear tests on 8-ply quasi-isotropic carbon fiber/epoxy laminates was determined by optical photogrammetry using an ARAMIS system. Specimens having non-optimal geometry and minor discrepancies in dimensional tolerances were shown to display non-symmetry and/or stress concentration in the vicinity of the notch relative to a specimen meeting the requirements of the standard, but resulting shear strength and modulus values remained within acceptable bounds of standard deviation. Based on these results, and reported difficulty machining specimens to the required tolerances using available methods, it is suggested that a parametric study combining analytical methods and experiment may provide rationale to increase the tolerances on some specimen dimensions, reducing machining costs, increasing the proportion of acceptable results, and enabling a wider adoption of the test method.

Application of stereo x-ray photogrammetry (SRM) in the determination of absorbed dose values during intracavitary radiation therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Kleffens, H.J.; Star, W.M.

1979-04-01

The method of stereo x-ray photogrammetry is described, using a stereo x-ray comparator, as well as some clinical applications. The x-ray equipment consists of two x-ray tubes and a pneumatically driven cassette changer, developed to reduce effects of patient or organ motion between stero radiographs. The accuracy of the set-up is demonstated with measurements on a geometrical model and on a gelatine phantom containing radium needles. The clinical use is reported in determining dose rates to points of the intestinal wall during intracavitary radiotherapy of gynecological cancer. In a number of cases the stereo measurements have resulted in a changemore » in the application time or in the charge or position of the applicator, possibly preventing later complications, as a result of a high dose. Future applications for implant dosimetry (/sup 192/Ir, /sup 125/I) are suggested.« less

Photogrammetry of a 5m Inflatable Space Antenna With Consumer Digital Cameras

NASA Technical Reports Server (NTRS)

Pappa, Richard S.; Giersch, Louis R.; Quagliaroli, Jessica M.

2000-01-01

This paper discusses photogrammetric measurements of a 5m-diameter inflatable space antenna using four Kodak DC290 (2.1 megapixel) digital cameras. The study had two objectives: 1) Determine the photogrammetric measurement precision obtained using multiple consumer-grade digital cameras and 2) Gain experience with new commercial photogrammetry software packages, specifically PhotoModeler Pro from Eos Systems, Inc. The paper covers the eight steps required using this hardware/software combination. The baseline data set contained four images of the structure taken from various viewing directions. Each image came from a separate camera. This approach simulated the situation of using multiple time-synchronized cameras, which will be required in future tests of vibrating or deploying ultra-lightweight space structures. With four images, the average measurement precision for more than 500 points on the antenna surface was less than 0.020 inches in-plane and approximately 0.050 inches out-of-plane.

Photogrammetry of the three-dimensional shape and texture of a nanoscale particle using scanning electron microscopy and free software.

PubMed

Gontard, Lionel C; Schierholz, Roland; Yu, Shicheng; Cintas, Jesús; Dunin-Borkowski, Rafal E

2016-10-01

We apply photogrammetry in a scanning electron microscope (SEM) to study the three-dimensional shape and surface texture of a nanoscale LiTi2(PO4)3 particle. We highlight the fact that the technique can be applied non-invasively in any SEM using free software (freeware) and does not require special sample preparation. Three-dimensional information is obtained in the form of a surface mesh, with the texture of the sample stored as a separate two-dimensional image (referred to as a UV Map). The mesh can be used to measure parameters such as surface area, volume, moment of inertia and center of mass, while the UV map can be used to study the surface texture using conventional image processing techniques. We also illustrate the use of 3D printing to visualize the reconstructed model. Copyright © 2016 Elsevier B.V. All rights reserved.

Algorithms and methodology used in constructing high-resolution terrain databases

NASA Astrophysics Data System (ADS)

Williams, Bryan L.; Wilkosz, Aaron

1998-07-01

This paper presents a top-level description of methods used to generate high-resolution 3D IR digital terrain databases using soft photogrammetry. The 3D IR database is derived from aerial photography and is made up of digital ground plane elevation map, vegetation height elevation map, material classification map, object data (tanks, buildings, etc.), and temperature radiance map. Steps required to generate some of these elements are outlined. The use of metric photogrammetry is discussed in the context of elevation map development; and methods employed to generate the material classification maps are given. The developed databases are used by the US Army Aviation and Missile Command to evaluate the performance of various missile systems. A discussion is also presented on database certification which consists of validation, verification, and accreditation procedures followed to certify that the developed databases give a true representation of the area of interest, and are fully compatible with the targeted digital simulators.

Comparative Geometrical Investigations of Hand-Held Scanning Systems

NASA Astrophysics Data System (ADS)

Kersten, T. P.; Przybilla, H.-J.; Lindstaedt, M.; Tschirschwitz, F.; Misgaiski-Hass, M.

2016-06-01

An increasing number of hand-held scanning systems by different manufacturers are becoming available on the market. However, their geometrical performance is little-known to many users. Therefore the Laboratory for Photogrammetry & Laser Scanning of the HafenCity University Hamburg has carried out geometrical accuracy tests with the following systems in co-operation with the Bochum University of Applied Sciences (Laboratory for Photogrammetry) as well as the Humboldt University in Berlin (Institute for Computer Science): DOTProduct DPI-7, Artec Spider, Mantis Vision F5 SR, Kinect v1 + v2, Structure Sensor and Google's Project Tango. In the framework of these comparative investigations geometrically stable reference bodies were used. The appropriate reference data were acquired by measurement with two structured light projection systems (AICON smartSCAN and GOM ATOS I 2M). The comprehensive test results of the different test scenarios are presented and critically discussed in this contribution.

Auto-calibration of GF-1 WFV images using flat terrain

NASA Astrophysics Data System (ADS)

Zhang, Guo; Xu, Kai; Huang, Wenchao

2017-12-01

Four wide field view (WFV) cameras with 16-m multispectral medium-resolution and a combined swath of 800 km are onboard the Gaofen-1 (GF-1) satellite, which can increase the revisit frequency to less than 4 days and enable large-scale land monitoring. The detection and elimination of WFV camera distortions is key for subsequent applications. Due to the wide swath of WFV images, geometric calibration using either conventional methods based on the ground control field (GCF) or GCF independent methods is problematic. This is predominantly because current GCFs in China fail to cover the whole WFV image and most GCF independent methods are used for close-range photogrammetry or computer vision fields. This study proposes an auto-calibration method using flat terrain to detect nonlinear distortions of GF-1 WFV images. First, a classic geometric calibration model is built for the GF1 WFV camera, and at least two images with an overlap area that cover flat terrain are collected, then the elevation residuals between the real elevation and that calculated by forward intersection are used to solve nonlinear distortion parameters in WFV images. Experiments demonstrate that the orientation accuracy of the proposed method evaluated by GCF CPs is within 0.6 pixel, and residual errors manifest as random errors. Validation using Google Earth CPs further proves the effectiveness of auto-calibration, and the whole scene is undistorted compared to not using calibration parameters. The orientation accuracy of the proposed method and the GCF method is compared. The maximum difference is approximately 0.3 pixel, and the factors behind this discrepancy are analyzed. Generally, this method can effectively compensate for distortions in the GF-1 WFV camera.

Crowd-sourced pictures geo-localization method based on street view images and 3D reconstruction

NASA Astrophysics Data System (ADS)

Cheng, Liang; Yuan, Yi; Xia, Nan; Chen, Song; Chen, Yanming; Yang, Kang; Ma, Lei; Li, Manchun

2018-07-01

People are increasingly becoming accustomed to taking photos of everyday life in modern cities and uploading them on major photo-sharing social media sites. These sites contain numerous pictures, but some have incomplete or blurred location information. The geo-localization of crowd-sourced pictures enriches the information contained therein, and is applicable to activities such as urban construction, urban landscape analysis, and crime tracking. However, geo-localization faces huge technical challenges. This paper proposes a method for large-scale geo-localization of crowd-sourced pictures. Our approach uses structured, organized Street View images as a reference dataset and employs a three-step strategy of coarse geo-localization by image retrieval, selecting reliable matches by image registration, and fine geo-localization by 3D reconstruction to attach geographic tags to pictures from unidentified sources. In study area, 3D reconstruction based on close-range photogrammetry is used to restore the 3D geographical information of the crowd-sourced pictures, resulting in the proposed method improving the median error from 256.7 m to 69.0 m, and the percentage of the geo-localized query pictures under a 50 m error from 17.2% to 43.2% compared with the previous method. Another discovery using the proposed method is that, in respect of the causes of reconstruction error, closer distances from the cameras to the main objects in query pictures tend to produce lower errors and the component of error parallel to the road makes a more significant contribution to the Total Error. The proposed method is not limited to small areas, and could be expanded to cities and larger areas owing to its flexible parameters.

From Tls Survey to 3d Solid Modeling for Documentation of Built Heritage: the Case Study of Porta Savonarola in Padua

NASA Astrophysics Data System (ADS)

Guarnieri, A.; Fissore, F.; Masiero, A.; Vettore, A.

2017-08-01

It is a matter of fact that 3D visualisation and proper documentation of cultural objects helps to preserve the history and memories of historic buildings, archaeological sites and cultural landscapes, and supports economic growth by stimulating cultural tourism. Preservation, visualisation and recreation of valuable historical and architectural objects and places has always been a serious challenge for specialists in the field. Today, the rapid developments in the fields of close-range photogrammetry, terrestrial laser scanning (TLS) and computer vision (CV) enable to carry out highly accurate 3D models so as to be extremely effective and intuitive for users who have stringent requirements and high expectations. In this note we present the results of the survey and 3D modeling of an ancient gate, Porta Savonarola, located within the remains of the medieval town walls surrounding the historical city center of Padua, Italy. The work has been undertaken within the framework of the project "Walls Multimedia Museum" (WMM) promoted by the local private association "Padua Walls Committee". The goal of the project was to develop a prototype of an "extended" virtual museum, spreaded along most interesting locations of the town walls. The survey of the ancient gate was performed with a Leica C10 and P20 terrestrial laser scanners. Once the acquired scans were properly merged together, a solid model was generated from the global point cloud, and plans and elevations were extracted from it for restoration purposes. A short multimedia video was also created for the "Walls Multimedia Museum", showing both the outer and inner part of the gate. In the paper we will discuss all the steps and challenges addressed to provide the 3D solid model of Porta Savonarola from the TLS data.

Only Image Based for the 3d Metric Survey of Gothic Structures by Using Frame Cameras and Panoramic Cameras

NASA Astrophysics Data System (ADS)

Pérez Ramos, A.; Robleda Prieto, G.

2016-06-01

Indoor Gothic apse provides a complex environment for virtualization using imaging techniques due to its light conditions and architecture. Light entering throw large windows in combination with the apse shape makes difficult to find proper conditions to photo capture for reconstruction purposes. Thus, documentation techniques based on images are usually replaced by scanning techniques inside churches. Nevertheless, the need to use Terrestrial Laser Scanning (TLS) for indoor virtualization means a significant increase in the final surveying cost. So, in most cases, scanning techniques are used to generate dense point clouds. However, many Terrestrial Laser Scanner (TLS) internal cameras are not able to provide colour images or cannot reach the image quality that can be obtained using an external camera. Therefore, external quality images are often used to build high resolution textures of these models. This paper aims to solve the problem posted by virtualizing indoor Gothic churches, making that task more affordable using exclusively techniques base on images. It reviews a previous proposed methodology using a DSRL camera with 18-135 lens commonly used for close range photogrammetry and add another one using a HDR 360° camera with four lenses that makes the task easier and faster in comparison with the previous one. Fieldwork and office-work are simplified. The proposed methodology provides photographs in such a good conditions for building point clouds and textured meshes. Furthermore, the same imaging resources can be used to generate more deliverables without extra time consuming in the field, for instance, immersive virtual tours. In order to verify the usefulness of the method, it has been decided to apply it to the apse since it is considered one of the most complex elements of Gothic churches and it could be extended to the whole building.

Big data; sensor networks and remotely-sensed data for mapping; feature extraction from lidar

NASA Astrophysics Data System (ADS)

Tlhabano, Lorato

2018-05-01

Unmanned aerial vehicles (UAVs) can be used for mapping in the close range domain, combining aerial and terrestrial photogrammetry and now the emergence of affordable platforms to carry these technologies has opened up new opportunities for mapping and modeling cadastral boundaries. At the current state mainly low cost UAVs fitted with sensors are used in mapping projects with low budgets, the amount of data produced by the UAVs can be enormous hence the need for big data techniques' and concepts. The past couple of years have witnessed the dramatic rise of low-cost UAVs fitted with high tech Lidar sensors and as such the UAVS have now reached a level of practical reliability and professionalism which allow the use of these systems as mapping platforms. UAV based mapping provides not only the required accuracy with respect to cadastral laws and policies as well as requirements for feature extraction from the data sets and maps produced, UAVs are also competitive to other measurement technologies in terms of economic aspects. In the following an overview on how the various technologies of UAVs, big data concepts and lidar sensor technologies can work together to revolutionize cadastral mapping particularly in Africa and as a test case Botswana in particular will be used to investigate these technologies. These technologies can be combined to efficiently provide cadastral mapping in difficult to reach areas and over large areas of land similar to the Land Administration Procedures, Capacity and Systems (LAPCAS) exercise which was recently undertaken by the Botswana government, we will show how the uses of UAVS fitted with lidar sensor and utilizing big data concepts could have reduced not only costs and time for our government but also how UAVS could have provided more detailed cadastral maps.

Towards a Low-Cost Real-Time Photogrammetric Landslide Monitoring System Utilising Mobile and Cloud Computing Technology

NASA Astrophysics Data System (ADS)

Chidburee, P.; Mills, J. P.; Miller, P. E.; Fieber, K. D.

2016-06-01

Close-range photogrammetric techniques offer a potentially low-cost approach in terms of implementation and operation for initial assessment and monitoring of landslide processes over small areas. In particular, the Structure-from-Motion (SfM) pipeline is now extensively used to help overcome many constraints of traditional digital photogrammetry, offering increased user-friendliness to nonexperts, as well as lower costs. However, a landslide monitoring approach based on the SfM technique also presents some potential drawbacks due to the difficulty in managing and processing a large volume of data in real-time. This research addresses the aforementioned issues by attempting to combine a mobile device with cloud computing technology to develop a photogrammetric measurement solution as part of a monitoring system for landslide hazard analysis. The research presented here focusses on (i) the development of an Android mobile application; (ii) the implementation of SfM-based open-source software in the Amazon cloud computing web service, and (iii) performance assessment through a simulated environment using data collected at a recognized landslide test site in North Yorkshire, UK. Whilst the landslide monitoring mobile application is under development, this paper describes experiments carried out to ensure effective performance of the system in the future. Investigations presented here describe the initial assessment of a cloud-implemented approach, which is developed around the well-known VisualSFM algorithm. Results are compared to point clouds obtained from alternative SfM 3D reconstruction approaches considering a commercial software solution (Agisoft PhotoScan) and a web-based system (Autodesk 123D Catch). Investigations demonstrate that the cloud-based photogrammetric measurement system is capable of providing results of centimeter-level accuracy, evidencing its potential to provide an effective approach for quantifying and analyzing landslide hazard at a local-scale.

An Automatic Procedure for Combining Digital Images and Laser Scanner Data

NASA Astrophysics Data System (ADS)

Moussa, W.; Abdel-Wahab, M.; Fritsch, D.

2012-07-01

Besides improving both the geometry and the visual quality of the model, the integration of close-range photogrammetry and terrestrial laser scanning techniques directs at filling gaps in laser scanner point clouds to avoid modeling errors, reconstructing more details in higher resolution and recovering simple structures with less geometric details. Thus, within this paper a flexible approach for the automatic combination of digital images and laser scanner data is presented. Our approach comprises two methods for data fusion. The first method starts by a marker-free registration of digital images based on a point-based environment model (PEM) of a scene which stores the 3D laser scanner point clouds associated with intensity and RGB values. The PEM allows the extraction of accurate control information for the direct computation of absolute camera orientations with redundant information by means of accurate space resection methods. In order to use the computed relations between the digital images and the laser scanner data, an extended Helmert (seven-parameter) transformation is introduced and its parameters are estimated. Precedent to that, in the second method, the local relative orientation parameters of the camera images are calculated by means of an optimized Structure and Motion (SaM) reconstruction method. Then, using the determined transformation parameters results in having absolute oriented images in relation to the laser scanner data. With the resulting absolute orientations we have employed robust dense image reconstruction algorithms to create oriented dense image point clouds, which are automatically combined with the laser scanner data to form a complete detailed representation of a scene. Examples of different data sets are shown and experimental results demonstrate the effectiveness of the presented procedures.

Action cameras and low-cost aerial vehicles in archaeology

NASA Astrophysics Data System (ADS)

Ballarin, M.; Balletti, C.; Guerra, F.

2015-05-01

This research is focused on the analysis of the potential of a close range aerial photogrammetry system, which is accessible both in economic terms and in terms of simplicity of use. In particular the Go Pro Hero3 Black Edition and the Parrot Ar. Drone 2.0 were studied. There are essentially two limitations to the system and they were found for both the instruments used. Indeed, the frames captured by the Go Pro are subject to great distortion and consequently pose numerous calibration problems. On the other hand, the limitation of the system lies in the difficulty of maintaining a flight configuration suitable for photogrammetric purposes in unfavourable environmental conditions. The aim of this research is to analyse how far the limitations highlighted can influence the precision of the survey and consequent quality of the results obtained. To this end, the integrated GoPro and Parrot system was used during a survey campaign on the Altilia archaeological site, in Molise. The data obtained was compared with that gathered by more traditional methods, such as the laser scanner. The system was employed in the field of archaeology because here the question of cost often has a considerable importance and the metric aspect is frequently subordinate to the qualitative and interpretative aspects. Herein one of the products of these systems; the orthophoto will be analysed, which is particularly useful in archaeology, especially in situations such as this dig in which there aren't many structures in elevation present. The system proposed has proven to be an accessible solution for producing an aerial documentation, which adds the excellent quality of the result to metric data for which the precision is known.

Photogrammetric Correlation of Face with Frontal Radiographs and Direct Measurements.

PubMed

Negi, Gunjan; Ponnada, Swaroopa; Aravind, N K S; Chitra, Prasad

2017-05-01

Photogrammetry is a science of making measurements from photographs. As cephalometric analysis till date has focused mainly on skeletal relationships, photogrammetry may provide a means to reliably assess and compare soft tissue and hard tissue measurements. To compare and correlate linear measurements taken directly from subject's faces and from standardized frontal cephalometric radiographs and to correlate them with standardized frontal facial photographs of Indian population and to obtain mean values. A cross-sectional study was conducted on 30 subjects of Indian origin. Frontal cephalograms and standardized frontal photographs were obtained from subjects in the age group of 18- 25 years. Vernier calipers were used to obtain facial measurements directly. Photographs and radiographs were uploaded and measured using Nemoceph software. Analogous cephalometric, photographic and direct measurements were compared by one-way ANOVA to assess Pearson correlation coefficients for 12 linear measurements (6 vertical, 6 horizontal). Bonferroni post-hoc test was done for pair wise comparison. Among all measurements used, O R -O L (orbitale right-orbitale left) showed a high correlation r = 0.76, 0.70, 0.71. There was moderate correlation with En R -En L (endocanthion rt - endocanthion lt) r 2 = 0.62, 0.68, 0.68. Highly significant correlation was evident with N-Sn, En R -En L and Ag R -Ag L with p<0.001. A statistically significant correlation was found between photographic, radiographic and direct measurements. Therefore, photogrammetry has proven to be an alternative diagnostic tool that can be used in epidemiologic studies when there is a need for a simple, basic, non-invasive and cost-effective method.

Capturing volcanic plumes in 3D with UAV-based photogrammetry at Yasur Volcano - Vanuatu

NASA Astrophysics Data System (ADS)

Gomez, C.; Kennedy, B.

2018-01-01

As a precise volume of volcanic ash-plume is essential to understand the dynamic of gas emission, exchanges and the eruptive dynamics, we have measured in 3D using photogrammetry a small-size volcanic plume at the summit of Yasur Volcano, Vanuatu. The objective was to collect the altitude and planform shape of the plume as well as the vertical variations of the shape and size. To reach this objective, the authors have used the Structure from Motion photogrammetric method applied to a series of photographs captured in a very short period of time around and above the plume. A total of 146 photographs at 3000 × 4000 pixel were collected as well as the geolocation, the pitch, tilt and orientation of the cameras. The results revealed a "mushroom"-like shape of the plume with a narrow ascending column topped by a turbulent mixing zone. The volume of the plume was calculated to be 13,430 m3 ± 512 m3 (with the error being the cube of the linear error from the Ground Control Points) for a maximum height above the terrain of 63 m. The included error was also kept high because of the irregular distribution of the Ground Control Points that could not be collected in dangerous areas due to the ongoing eruption. Based on this research, it is therefore worth investigating the usage of multiple cameras to capture plumes in 3D over time and the method is also a good complement to the recent development of photogrammetry from space, which can tackle larger-scale eruption plumes.

Photogrammetry research for FAST eleven-meter reflector panel surface shape measurement

NASA Astrophysics Data System (ADS)

Zhou, Rongwei; Zhu, Lichun; Li, Weimin; Hu, Jingwen; Zhai, Xuebing

2010-10-01

In order to design and manufacture the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) active reflector measuring equipment, measurement on each reflector panel surface shape was presented, static measurement of the whole neutral spherical network of nodes was performed, real-time dynamic measurement at the cable network dynamic deformation was undertaken. In the implementation process of the FAST, reflector panel surface shape detection was completed before eleven-meter reflector panel installation. Binocular vision system was constructed based on the method of binocular stereo vision in machine vision, eleven-meter reflector panel surface shape was measured with photogrammetry method. Cameras were calibrated with the feature points. Under the linearity camera model, the lighting spot array was used as calibration standard pattern, and the intrinsic and extrinsic parameters were acquired. The images were collected for digital image processing and analyzing with two cameras, feature points were extracted with the detection algorithm of characteristic points, and those characteristic points were matched based on epipolar constraint method. Three-dimensional reconstruction coordinates of feature points were analyzed and reflective panel surface shape structure was established by curve and surface fitting method. The error of reflector panel surface shape was calculated to realize automatic measurement on reflector panel surface shape. The results show that unit reflector panel surface inspection accuracy was 2.30mm, within the standard deviation error of 5.00mm. Compared with the requirement of reflector panel machining precision, photogrammetry has fine precision and operation feasibility on eleven-meter reflector panel surface shape measurement for FAST.

Integrated Processing of High Resolution Topographic Data for Soil Erosion Assessment Considering Data Acquisition Schemes and Surface Properties

NASA Astrophysics Data System (ADS)

Eltner, A.; Schneider, D.; Maas, H.-G.

2016-06-01

Soil erosion is a decisive earth surface process strongly influencing the fertility of arable land. Several options exist to detect soil erosion at the scale of large field plots (here 600 m²), which comprise different advantages and disadvantages depending on the applied method. In this study, the benefits of unmanned aerial vehicle (UAV) photogrammetry and terrestrial laser scanning (TLS) are exploited to quantify soil surface changes. Beforehand data combination, TLS data is co-registered to the DEMs generated with UAV photogrammetry. TLS data is used to detect global as well as local errors in the DEMs calculated from UAV images. Additionally, TLS data is considered for vegetation filtering. Complimentary, DEMs from UAV photogrammetry are utilised to detect systematic TLS errors and to further filter TLS point clouds in regard to unfavourable scan geometry (i.e. incidence angle and footprint) on gentle hillslopes. In addition, surface roughness is integrated as an important parameter to evaluate TLS point reliability because of the increasing footprints and thus area of signal reflection with increasing distance to the scanning device. The developed fusion tool allows for the estimation of reliable data points from each data source, considering the data acquisition geometry and surface properties, to finally merge both data sets into a single soil surface model. Data fusion is performed for three different field campaigns at a Mediterranean field plot. Successive DEM evaluation reveals continuous decrease of soil surface roughness, reappearance of former wheel tracks and local soil particle relocation patterns.

A systematic review of the angular values obtained by computerized photogrammetry in sagittal plane: a proposal for reference values.

PubMed

Krawczky, Bruna; Pacheco, Antonio G; Mainenti, Míriam R M

2014-05-01

Reference values for postural alignment in the coronal plane, as measured by computerized photogrammetry, have been established but not for the sagittal plane. The objective of this study is to propose reference values for angular measurements used for postural analysis in the sagittal plane for healthy adults. Electronic databases (PubMed, BVS, Cochrane, Scielo, and Science Direct) were searched using the following key words: evaluation, posture, photogrammetry, and software. Articles published between 2006 and 2012 that used the PAS/SAPO (postural assessment software) were selected. Another inclusion criterion was the presentation of, at least, one of the following measurements: head horizontal alignment, pelvic horizontal alignment, hip angle, vertical alignment of the body, thoracic kyphosis, and lumbar lordosis. Angle samples of the selected articles were grouped 2 by 2 in relation to an overall average, which made possible total average, variance, and SD calculations. Six articles were included, and the following average angular values were found: 51.42° ± 4.87° (head horizontal alignment), -12.26° ± 5.81° (pelvic horizontal alignment), -6.40° ± 3.86° (hip angle), and 1.73° ± 0.94° (vertical alignment of the body). None of the articles contained the measurements for thoracic kyphosis and lumbar lordosis. The reference values can be adopted as reference for postural assessment in future researches if the same anatomical points are considered. Copyright © 2014 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

Use of Assisted Photogrammetry for Indoor and Outdoor Navigation Purposes

NASA Astrophysics Data System (ADS)

Pagliari, D.; Cazzaniga, N. E.; Pinto, L.

2015-05-01

Nowadays, devices and applications that require navigation solutions are continuously growing. For instance, consider the increasing demand of mapping information or the development of applications based on users' location. In some case it could be sufficient an approximate solution (e.g. at room level), but in the large amount of cases a better solution is required. The navigation problem has been solved from a long time using Global Navigation Satellite System (GNSS). However, it can be unless in obstructed areas, such as in urban areas or inside buildings. An interesting low cost solution is photogrammetry, assisted using additional information to scale the photogrammetric problem and recovering a solution also in critical situation for image-based methods (e.g. poor textured surfaces). In this paper, the use of assisted photogrammetry has been tested for both outdoor and indoor scenarios. Outdoor navigation problem has been faced developing a positioning system with Ground Control Points extracted from urban maps as constrain and tie points automatically extracted from the images acquired during the survey. The proposed approach has been tested under different scenarios, recovering the followed trajectory with an accuracy of 0.20 m. For indoor navigation a solution has been thought to integrate the data delivered by Microsoft Kinect, by identifying interesting features on the RGB images and re-projecting them on the point clouds generated from the delivered depth maps. Then, these points have been used to estimate the rotation matrix between subsequent point clouds and, consequently, to recover the trajectory with few centimeters of error.

Photometric Evaluation in Adolescence of Patients With Bilateral Cleft Lip and Palate Treated With Nasoalveolar Molding and Primary Columella Lengthening.

PubMed

Meazzini, Maria Costanza; Chiavenna, Carlo; Autelitano, Luca; Garattini, Giovanna; Brusati, Roberto

2018-04-01

Nasal stigma in patients with bilateral cleft lip and palate (BCLP) are a short columella and a flattened nasal tip. The aim of this study was to evaluate the aesthetics of adolescents with BCLP, operated with a modified Cutting primary columella lengthening technique, associated to a modified Grayson orthopedic nasoalveolar molding (NAM). 72 BCLP patients were operated with this approach. Standardized photographic records were taken every 2 years. A group of 23 patients between 12 and 13 years of age was compared through normalized photogrammetry to a matched control of 23 noncleft adolescents. Nasal protrusion and length of the columella were very close to normal. On the other hand, nasolabial angle and interalar width were still excessively wide compared to the noncleft sample. NAM and primary columella lengthening in BCLP has allowed to avoid traditional secondary columella lengthening at 5 to 6 years of age and given the patients a more pleasing, near-normal nasolabial appearance until adolescence. Some of the patients will require correction of the nasal width at a later stage.

Development of Open source-based automatic shooting and processing UAV imagery for Orthoimage Using Smart Camera UAV

NASA Astrophysics Data System (ADS)

Park, J. W.; Jeong, H. H.; Kim, J. S.; Choi, C. U.

2016-06-01

Recently, aerial photography with unmanned aerial vehicle (UAV) system uses UAV and remote controls through connections of ground control system using bandwidth of about 430 MHz radio Frequency (RF) modem. However, as mentioned earlier, existing method of using RF modem has limitations in long distance communication. The Smart Camera equipments's LTE (long-term evolution), Bluetooth, and Wi-Fi to implement UAV that uses developed UAV communication module system carried out the close aerial photogrammetry with the automatic shooting. Automatic shooting system is an image capturing device for the drones in the area's that needs image capturing and software for loading a smart camera and managing it. This system is composed of automatic shooting using the sensor of smart camera and shooting catalog management which manages filmed images and information. Processing UAV imagery module used Open Drone Map. This study examined the feasibility of using the Smart Camera as the payload for a photogrammetric UAV system. The open soure tools used for generating Android, OpenCV (Open Computer Vision), RTKLIB, Open Drone Map.

Unmanned aircraft systems: a new tool for DOT inspections : final report

DOT National Transportation Integrated Search

2016-10-31

The NextGen Air Transportation Program (NGAT) at North Carolina State University (NCSU) collaborated with the NCDOT departments (Location and Surveys, Photogrammetry, Aviation, etc.) to analyze the potential role of small Unmanned Aerial Systems (UAS...

Topography changes monitoring of small islands using camera drone

NASA Astrophysics Data System (ADS)

Bang, E.

2017-12-01

Drone aerial photogrammetry was conducted for monitoring topography changes of small islands in the east sea of Korea. Severe weather and sea wave is eroding the islands and sometimes cause landslide and falling rock. Due to rugged cliffs in all direction and bad accessibility, ground based survey methods are less efficient in monitoring topography changes of the whole area. Camera drones can provide digital images and movie in every corner of the islands, and drone aerial photogrammetry is powerful to get precise digital surface model (DSM) for a limited area. We have got a set of digital images to construct a textured 3D model of the project area every year since 2014. Flight height is in less than 100m from the top of those islands to get enough ground sampling distance (GSD). Most images were vertically captured with automatic flights, but we also flied drones around the islands with about 30°-45° camera angle for constructing 3D model better. Every digital image has geo-reference, but we set several ground control points (GCPs) on the islands and their coordinates were measured with RTK surveying methods to increase the absolute accuracy of the project. We constructed 3D textured model using photogrammetry tool, which generates 3D spatial information from digital images. From the polygonal model, we could get DSM with contour lines. Thematic maps such as hill shade relief map, aspect map and slope map were also processed. Those maps make us understand topography condition of the project area better. The purpose of this project is monitoring topography change of these small islands. Elevation difference map between DSMs of each year is constructed. There are two regions showing big negative difference value. By comparing constructed textured models and captured digital images around these regions, it is checked that a region have experienced real topography change. It is due to huge rock fall near the center of the east island. The size of fallen rock can be measured on the digital model exactly, which is about 13m*6m*2m (height*width*thickness). We believe that drone aerial photogrammetry can be an efficient topography changes detection method for a complicated terrain area.

Long-range active retroreflector to measure the rotational orientation in conjunction with a laser tracker

NASA Astrophysics Data System (ADS)

Hofherr, O.; Wachten, Christian; Müller, C.; Reinecke, H.

2014-11-01

High precision optical non-contact position measurement is a key technology in modern engineering. Laser trackers (LT) accurately determine x-y-z coordinates of passive retroreflectors. Next-generation systems answer the need to measure an object`s rotational orientation (pitch, yaw, roll). So far, these devices are based either on photogrammetry or on enhanced retroreflectors. Here we present a new method to measure all six degrees of freedom in conjunction with a LT. The basic principle is to analyze the orientation to the LT's beam path by coupling-out laser radiation. The optical design is inspired by a cat's eye retroreflector equipped with an integrated beam splitter layer. The optical spherical aberration is compensated, which reduces the divergence angle for the reflected beam by one order of magnitude compared to an uncompensated standard system of the same size. The wave front distortion is reduced to less than 0.1 λ @ 633 nm for beam diameters up to 8 mm. Our active retroreflector is suitable for long-range measurements for a distance > 10 m.

Stereochronoscopy of the optic disc with stereoscopic cameras.

PubMed

Schirmer, K E; Kratky, V

1980-09-01

Goldmann's chronoscopy, a form of time-based photogrammetry of the optic disc, can be accomplished by repeated simultaneous stereophotography. The variations in centration and image orientation are nulled by azimuthal rotation and fusion of two pairs of stereophotographs taken at separate times.

Close Range Photogrammetry Applied to the Documentation of AN Archaeological Site in Gaza Strip, Palestine

NASA Astrophysics Data System (ADS)

Alby, E.; Elter, R.; Ripoche, C.; Quere, N.; de Strasbourg, INSA

2013-07-01

In a geopolitical very complex context as the Gaza Strip it has to be dealt with an enhancement of an archaeological site. This site is the monastery of St. Hilarion. To enable a cultural appropriation of a place with several identified phases of occupation must undertake extensive archaeological excavation. Excavate in this geographical area is to implement emergency excavations, so the aim of such a project can be questioned for each mission. Real estate pressure is also a motivating setting the documentation because the large population density does not allow systematic studies of underground before construction projects. This is also during the construction of a road that the site was discovered. Site dimensions are 150 m by 80 m. It is located on a sand dune, 300 m from the sea. To implement the survey, four different levels of detail have been defined for terrestrial photogrammetry. The first level elements are similar to objects, capitals, fragment of columns, tiles for example. Modeling of small objects requires the acquisition of very dense point clouds (density: 1 point / 1 mm on average). The object must then be a maximum area of the sensor of the camera, while retaining in the field of view a reference pattern for the scaling of the point cloud generated. The pictures are taken at a short distance from the object, using the images at full resolution. The main obstacle to the modeling of objects is the presence of noise partly due to the studied materials (sand, smooth rock), which do not favor the detection of points of interest quality. Pretreatments of the cloud will be achieved meticulously since the ouster of points on a surface of a small object results in the formation of a hole with a lack of information, useful to resulting mesh. Level 2 focuses on the stratigraphic units such as mosaics. The monastery of St. Hilarion identifies thirteen floors of which has been documented years ago by silver photographs, scanned later. Modeling of pavements is to obtain a three-dimensional model of the mosaic in particular to analyze the subsidence, which it may be subjected. The dense point cloud can go beyond by including the geometric shapes of the pavement. The calculation mesh using high-density point cloud colorization allows cloud sufficient to final rendering. Levels 3 and 4 will allow the survey and representation of loci and sectors. Their modeling can be done by colored mesh or textured by a generic pattern but also by geometric primitives. This method requires the segmentation simple geometrical elements and creates a surface geometry by analysis of the sample points. Statistical tools allow the extraction plans meet the requirements of the operator can monitor quantitatively the quality of the final rendering. Each level has constraints on the accuracy of survey and types of representation especially from the point clouds, which are detailed in the complete article.

A convenient and accurate wide-range parameter relationship between Buckingham and Morse potential energy functions

NASA Astrophysics Data System (ADS)

Lim, Teik-Cheng; Dawson, James Alexander

2018-05-01

This study explores the close-range, short-range and long-range relationships between the parameters of the Morse and Buckingham potential energy functions. The results show that the close-range and short-range relationships are valid for bond compression and for very small changes in bond length, respectively, while the long-range relationship is valid for bond stretching. A wide-range relationship is proposed to combine the comparative advantages of the close-range, short-range and long-range parameter relationships. The wide-range relationship is useful for replacing the close-range, short-range and long-range parameter relationships, thereby preventing the undesired effects of potential energy jumps resulting from functional switching between the close-range, short-range and long-range interaction energies.

Assessing the consistency of UAV-derived point clouds and images acquired at different altitudes

NASA Astrophysics Data System (ADS)

Ozcan, O.

2016-12-01

Unmanned Aerial Vehicles (UAVs) offer several advantages in terms of cost and image resolution compared to terrestrial photogrammetry and satellite remote sensing system. Nowadays, UAVs that bridge the gap between the satellite scale and field scale applications were initiated to be used in various application areas to acquire hyperspatial and high temporal resolution imageries due to working capacity and acquiring in a short span of time with regard to conventional photogrammetry methods. UAVs have been used for various fields such as for the creation of 3-D earth models, production of high resolution orthophotos, network planning, field monitoring and agricultural lands as well. Thus, geometric accuracy of orthophotos and volumetric accuracy of point clouds are of capital importance for land surveying applications. Correspondingly, Structure from Motion (SfM) photogrammetry, which is frequently used in conjunction with UAV, recently appeared in environmental sciences as an impressive tool allowing for the creation of 3-D models from unstructured imagery. In this study, it was aimed to reveal the spatial accuracy of the images acquired from integrated digital camera and the volumetric accuracy of Digital Surface Models (DSMs) which were derived from UAV flight plans at different altitudes using SfM methodology. Low-altitude multispectral overlapping aerial photography was collected at the altitudes of 30 to 100 meters and georeferenced with RTK-GPS ground control points. These altitudes allow hyperspatial imagery with the resolutions of 1-5 cm depending upon the sensor being used. Preliminary results revealed that the vertical comparison of UAV-derived point clouds with respect to GPS measurements pointed out an average distance at cm-level. Larger values are found in areas where instantaneous changes in surface are present.

Characterization of Joint Sets Through UAV Photogrammetry on Sedimentary Rock Sea Cliffs and Abrasion Platforms in Northern Taiwan

NASA Astrophysics Data System (ADS)

Hsieh, P. C.; LU, A.; Yeh, C. H.; Huang, W. K.; Lin, H. H.; Lin, M. L.

2017-12-01

Rockfall hazards are very common in obsequent slope and oblique slope. In the coastal area of northern Taiwan, many sea cliffs are formed by obsequent slope and oblique slope. A famous case of rockfall failure happened on Aug. 31, 2013, a 150-ton rock block fell on the highway in Badouzi, Keelung, during a high intensity rainfall event which was caused by Typhoon No.15 (Kong-rey). To reduce this kind of rockfall hazard, it is important to characterize discontinuous planes in the bedrock because rock blocks are mainly divided from bedrock by two or more sets of discontinuous planes including joint planes and the bedding plane. For doing characterization of those fracture patterns of joint sets, it is necessary to do detailed field investigations. However, the survey of discontinuous planes, especially joint sets, are usually difficult and cannot get enough characterization data about joint sets. The first reason is that doing field investigations on the surface of sea cliffs is very dangerous and difficult for engineers or geologists to approach the upper part of outcrop. The second reason is the complexity of joint sets. In Badouzi area, each cliff is constituted by many different layers such as sandstone, shale, or alternations of sandstone and shale, and each layer has different fracture pattern of joint sets. In this study, we use UAV photogrammetry as a solution of these difficulties. UAV photogrammetry can produce a high-resolution digital surface model (DSM), orthophoto, and anaglyph of sea cliffs and abrasion platforms. Than we use self-developed geoprocessing toolsets to auto-trace joint planes with DSM data and produce fracture pattern of joint sets semi-automatically and systematically. Our method can provide basic information for rock mass rating on rock slope stability and rockfall hazards evaluation.

Sampling supraglacial debris thickness using terrestrial photogrammetry

NASA Astrophysics Data System (ADS)

Nicholson, Lindsey; Mertes, Jordan

2017-04-01

The melt rate of debris-covered ice differs to that of clean ice primarily as a function of debris thickness. The spatial distribution of supraglacial debris thickness must therefore be known in order to understand how it is likely to impact glacier behaviour, and meltwater contribution to local hydrological resources and global sea level rise. However, practical means of determining debris cover thickness remain elusive. In this study we explore the utility of terrestrial photogrammetry to produce high resolution, scaled and texturized digital terrain models of debris cover exposures above ice cliffs as a means of quantifying and characterizing debris thickness. Two Nikon D5000 DSLRs with Tamron 100mm lenses were used to photograph a sample area of the Ngozumpa glacier in the Khumbu Himal of Nepal in April 2016. A Structure from Motion workflow using Agisoft Photoscan software was used to generate a surface models with <10cm resolution. A Trimble Geo7X differential GPS with Zephyr antenna, along with a local base station, was used to precisely measure marked ground control points to scale the photogrammetric surface model. Measurements of debris thickness along the exposed cliffline were made from this scaled model, assuming that the ice surface at the debris-ice boundary is horizontal, and these data are compared to 50 manual point measurements along the same clifftops. We conclude that sufficiently high resolution photogrammetry, with precise scaling information, provides a useful means to determine debris thickness at clifftop exposures. The resolution of the possible measurements depends on image resolution, the accuracy of the ground control points and the computational capacity to generate centimetre scale surface models. Application of such techniques to sufficiently high resolution imagery from UAV-borne cameras may offer a powerful means of determining debris thickness distribution patterns over debris covered glacier termini.

High spatial resolution mapping of folds and fractures using Unmanned Aerial Vehicle (UAV) photogrammetry

NASA Astrophysics Data System (ADS)

Cruden, A. R.; Vollgger, S.

2016-12-01

The emerging capability of UAV photogrammetry combines a simple and cost-effective method to acquire digital aerial images with advanced computer vision algorithms that compute spatial datasets from a sequence of overlapping digital photographs from various viewpoints. Depending on flight altitude and camera setup, sub-centimeter spatial resolution orthophotographs and textured dense point clouds can be achieved. Orientation data can be collected for detailed structural analysis by digitally mapping such high-resolution spatial datasets in a fraction of time and with higher fidelity compared to traditional mapping techniques. Here we describe a photogrammetric workflow applied to a structural study of folds and fractures within alternating layers of sandstone and mudstone at a coastal outcrop in SE Australia. We surveyed this location using a downward looking digital camera mounted on commercially available multi-rotor UAV that autonomously followed waypoints at a set altitude and speed to ensure sufficient image overlap, minimum motion blur and an appropriate resolution. The use of surveyed ground control points allowed us to produce a geo-referenced 3D point cloud and an orthophotograph from hundreds of digital images at a spatial resolution < 10 mm per pixel, and cm-scale location accuracy. Orientation data of brittle and ductile structures were semi-automatically extracted from these high-resolution datasets using open-source software. This resulted in an extensive and statistically relevant orientation dataset that was used to 1) interpret the progressive development of folds and faults in the region, and 2) to generate a 3D structural model that underlines the complex internal structure of the outcrop and quantifies spatial variations in fold geometries. Overall, our work highlights how UAV photogrammetry can contribute to new insights in structural analysis.

Oblique Photogrammetry and Usage on Land Administration

NASA Astrophysics Data System (ADS)

Kisa, A.; Ozmus, L.; Erkek, B.; Ates, H. B.; Bakici, S.

2013-08-01

Projects based on Geographic Information Systems (GIS) have started within the body of the General Directorate of Land Registry and Cadastre (GDLRC) by the Land Registry and Cadastre Information System (LRCIS) in the beginning of 2000s. LRCIS was followed by other projects which are Turkish National Geographic Information System (TNGIS), Continuously Operating GPS Reference Stations (CORS-TR), Geo Metadata Portal (GMP), Orthophoto Web Services, Completion of Initial Cadastre, Cadastre Renovation Project (CRP), 2B and Land Registry Achieve Information System (LRAIS). When examining the projects generated by GDLRC, it is realized that they include basic functions of land administration required for sustainable development. Sustainable development is obtained through effective land administration as is known. Nowadays, land use becomes more intense as a result of rapid population increase. The importance of land ownership has increased accordingly. At this point, the necessity of cadastre appears. In Turkey, cadastral registration is carried out by the detection of parcels. In other words, it is obtained through the division of land surface into 2D boundaries and mapping of them. However, existing land administration systems have begun to lose their efficiency while coping with rights, restrictions and responsibilities (RRRs) belonging to land which become more complicated day by day. Overlapping and interlocking constructions appear particularly in urban areas with dense housing and consequently, the problem of how to project these structures onto the surface in 2D cadastral systems has arisen. Herein, the necessity of 3D cadastre concept and 3D property data is confronted. In recent years, oblique photogrammetry, whose applications are gradually spreading, is used as an effective method for producing 3D data. In this study, applications of oblique photogrammetry and usability of oblique images as base for 3D Cadastre and Land Administration projects are examined.

[The currently available possibilities for the application of photogrammetry in the forensic medical expertise of the blood stains at the scene of the crime].

PubMed

Fetisov, V A; Makarov, I Yu; Gusarov, A A; Lorents, A S; Smirenin, S A; Stragis, V B

The study of blood stains retained at the scene of the crime is of crucial importance for the preliminary inquiry. The present article is focused on the analysis of the possibilities and prospects for the use of photogrammetry (PM) as exemplified by the foreign expert practice of the blood stains examination at the site of the event. It is shown that the results of the application of digital photogrammetry in addition to the traditional methods of morphological investigations enables the forensic medical experts to reconstruct a number of unique features and circumstances that accompanied the commission of a crime at the site of the event. Such PM techniques supplemented by the ballistic analysis of the blood splatter and droplet trajectories provides additional evidence that allows the forensic medical experts to reconstruct the scene of the crime including the pose and position of the victim at the moment of causing injury. Moreover, these data make it possible to determine the maximum number and the sequence of injurious impacts (blows). The authors discuss the advantages and relative disadvantages of the application of the photogrammetric technique in the routine practical expert work. It is emphasized that the published decision making algorithms provide the specialists in various disciplines and professional experts with the ready-made technological tools for obtaining the additional criteria for the objective improvement of the quality of the studies they carry out and for the enhancement of the value of expert conclusions. It is concluded that the application of the modern photogrammetric technologies can be recommended for the solution of the applied forensic medical problems and conducting the relevant expert research.

Photogrammetry of the Human Brain: A Novel Method for Three-Dimensional Quantitative Exploration of the Structural Connectivity in Neurosurgery and Neurosciences.

PubMed

De Benedictis, Alessandro; Nocerino, Erica; Menna, Fabio; Remondino, Fabio; Barbareschi, Mattia; Rozzanigo, Umberto; Corsini, Francesco; Olivetti, Emanuele; Marras, Carlo Efisio; Chioffi, Franco; Avesani, Paolo; Sarubbo, Silvio

2018-04-13

Anatomic awareness of the structural connectivity of the brain is mandatory for neurosurgeons, to select the most effective approaches for brain resections. Although standard microdissection is a validated technique to investigate the different white matter (WM) pathways and to verify the results of tractography, the possibility of interactive exploration of the specimens and reliable acquisition of quantitative information has not been described. Photogrammetry is a well-established technique allowing an accurate metrology on highly defined three-dimensional (3D) models. The aim of this work is to propose the application of the photogrammetric technique for supporting the 3D exploration and the quantitative analysis on the cerebral WM connectivity. The main perisylvian pathways, including the superior longitudinal fascicle and the arcuate fascicle were exposed using the Klingler technique. The photogrammetric acquisition followed each dissection step. The point clouds were registered to a reference magnetic resonance image of the specimen. All the acquisitions were coregistered into an open-source model. We analyzed 5 steps, including the cortical surface, the short intergyral fibers, the indirect posterior and anterior superior longitudinal fascicle, and the arcuate fascicle. The coregistration between the magnetic resonance imaging mesh and the point clouds models was highly accurate. Multiple measures of distances between specific cortical landmarks and WM tracts were collected on the photogrammetric model. Photogrammetry allows an accurate 3D reproduction of WM anatomy and the acquisition of unlimited quantitative data directly on the real specimen during the postdissection analysis. These results open many new promising neuroscientific and educational perspectives and also optimize the quality of neurosurgical treatments. Copyright © 2018 Elsevier Inc. All rights reserved.

Measurement of clavicular length and shortening after a midshaft clavicular fracture: Spatial digitization versus planar roentgen photogrammetry.

PubMed

Stegeman, Sylvia A; de Witte, Pieter Bas; Boonstra, Sjoerd; de Groot, Jurriaan H; Nagels, Jochem; Krijnen, Pieta; Schipper, Inger B

2016-08-01

Clavicular shortening after fracture is deemed prognostic for clinical outcome and is therefore generally assessed on radiographs. It is used for clinical decision making regarding operative or non-operative treatment in the first 2weeks after trauma, although the reliability and accuracy of the measurements are unclear. This study aimed to assess the reliability of roentgen photogrammetry (2D) of clavicular length and shortening, and to compare these with 3D-spatial digitization measurements, obtained with an electromagnetic recording system (Flock of Birds). Thirty-two participants with a consolidated non-operatively treated two or multi-fragmented dislocated midshaft clavicular fracture were analysed. Two observers measured clavicular lengths and absolute and proportional clavicular shortening on radiographs taken before and after fracture consolidation. The clavicular lengths were also measured with spatial digitization. Inter-observer agreement on the radiographic measurements was assessed using the Intraclass Correlation Coefficient (ICC). Agreement between the radiographic and spatial digitization measurements was assessed using a Bland-Altman plot. The inter-observer agreement on clavicular length, and absolute and proportional shortening on trauma radiographs was almost perfect (ICC>0.90), but moderate for absolute shortening after consolidation (ICC=0.45). The Bland-Altman plot compared measurements of length on AP panorama radiographs with spatial digitization and showed that planar roentgen photogrammetry resulted in up to 37mm longer and 34mm shorter measurements than spatial digitization. Measurements of clavicular length on radiographs are highly reliable between observers, but may not reflect the actual length and shortening of the clavicle when compared to length measurements with spatial digitization. We recommend to use proportional shortening when measuring clavicular length or shortening on radiographs for clinical decision making. Copyright © 2015 Elsevier Ltd. All rights reserved.

New method of scoliosis assessment: preliminary results using computerized photogrammetry.

PubMed

Aroeira, Rozilene Maria Cota; Leal, Jefferson Soares; de Melo Pertence, Antônio Eustáquio

2011-09-01

A new method for nonradiographic evaluation of scoliosis was independently compared with the Cobb radiographic method, for the quantification of scoliotic curvature. To develop a protocol for computerized photogrammetry, as a nonradiographic method, for the quantification of scoliosis, and to mathematically relate this proposed method with the Cobb radiographic method. Repeated exposure to radiation of children can be harmful to their health. Nevertheless, no nonradiographic method until now proposed has gained popularity as a routine method for evaluation, mainly due to a low correspondence to the Cobb radiographic method. Patients undergoing standing posteroanterior full-length spine radiographs, who were willing to participate in this study, were submitted to dorsal digital photography in the orthostatic position with special surface markers over the spinous process, specifically the vertebrae C7 to L5. The radiographic and photographic images were sent separately for independent analysis to two examiners, trained in quantification of scoliosis for the types of images received. The scoliosis curvature angles obtained through computerized photogrammetry (the new method) were compared to those obtained through the Cobb radiographic method. Sixteen individuals were evaluated (14 female and 2 male). All presented idiopathic scoliosis, and were between 21.4 ± 6.1 years of age; 52.9 ± 5.8 kg in weight; 1.63 ± 0.05 m in height, with a body mass index of 19.8 ± 0.2. There was no statistically significant difference between the scoliosis angle measurements obtained in the comparative analysis of both methods, and a mathematical relationship was formulated between both methods. The preliminary results presented demonstrate equivalence between the two methods. More studies are needed to firmly assess the potential of this new method as a coadjuvant tool in the routine following of scoliosis treatment.

Application of Structure-from-Motion photogrammetry in laboratory flumes

NASA Astrophysics Data System (ADS)

Morgan, Jacob A.; Brogan, Daniel J.; Nelson, Peter A.

2017-01-01

Structure-from-Motion (SfM) photogrammetry has become widely used for topographic data collection in field and laboratory studies. However, the relative performance of SfM against other methods of topographic measurement in a laboratory flume environment has not been systematically evaluated, and there is a general lack of guidelines for SfM application in flume settings. As the use of SfM in laboratory flume settings becomes more widespread, it is increasingly critical to develop an understanding of how to acquire and process SfM data for a given flume size and sediment characteristics. In this study, we: (1) compare the resolution and accuracy of SfM topographic measurements to terrestrial laser scanning (TLS) measurements in laboratory flumes of varying physical dimensions containing sediments of varying grain sizes; (2) explore the effects of different image acquisition protocols and data processing methods on the resolution and accuracy of topographic data derived from SfM techniques; and (3) provide general guidance for image acquisition and processing for SfM applications in laboratory flumes. To investigate the effects of flume size, sediment size, and photo overlap on the density and accuracy of SfM data, we collected topographic data using both TLS and SfM in five flumes with widths ranging from 0.22 to 6.71 m, lengths ranging from 9.14 to 30.48 m, and median sediment sizes ranging from 0.2 to 31 mm. Acquisition time, image overlap, point density, elevation data, and computed roughness parameters were compared to evaluate the performance of SfM against TLS. We also collected images of a pan of gravel where we varied the distance and angle between the camera and sediment in order to explore how photo acquisition affects the ability to capture grain-scale microtopographic features in SfM-derived point clouds. A variety of image combinations and SfM software package settings were also investigated to determine optimal processing techniques. Results from this study suggest that SfM provides topographic data of similar accuracy to TLS, at higher resolution and lower cost. We found that about 100pixels per grain are required to resolve grain-scale topography. We suggest protocols for image acquisition and SfM software settings to achieve best results when using SfM in laboratory settings. In general, convergent imagery, taken from a higher angle, with at least several overlapping images for each desired point in the flume will result in an acceptable point cloud.

The Updating of Geospatial Base Data

NASA Astrophysics Data System (ADS)

Alrajhi, Muhamad N.; Konecny, Gottfried

2018-04-01

Topopographic mapping issues concern the area coverage at different scales and their age. The age of the map is determined by the system of updating. The United Nations (UNGGIM) have attempted to track the global map coverage at various scale ranges, which has greatly improved in recent decades. However the poor state of updating of base maps is still a global problem. In Saudi Arabia large scale mapping is carried out for all urban, suburban and rural areas by aerial surveys. Updating is carried out by remapping every 5 to 10 years. Due to the rapid urban development this is not satisfactory, but faster update methods are forseen by use of high resolution satellite imagery and the improvement of object oriented geodatabase structures, which will permit to utilize various survey technologies to update the photogrammetry established geodatabases. The longterm goal is to create an geodata infrastructure, which exists in Great Britain or Germany.

Blade Displacement Measurements of the Full-Scale UH-60A Airloads Rotor

NASA Technical Reports Server (NTRS)

Barrows, Danny A.; Burner, Alpheus W.; Abrego, Anita I.; Olson, Lawrence E.

2011-01-01

Blade displacement measurements were acquired during a wind tunnel test of the full-scale UH-60A Airloads rotor. The test was conducted in the 40- by 80-Foot Wind Tunnel of the National Full-Scale Aerodynamics Complex at NASA Ames Research Center. Multi-camera photogrammetry was used to measure the blade displacements of the four-bladed rotor. These measurements encompass a range of test conditions that include advance ratios from 0.15 to unique slowed-rotor simulations as high as 1.0, thrust coefficient to rotor solidity ratios from 0.01 to 0.13, and rotor shaft angles from -10.0 to 8.0 degrees. The objective of these measurements is to provide a benchmark blade displacement database to be utilized in the development and validation of rotorcraft computational tools. The methodology, system development, measurement techniques, and preliminary sample blade displacement measurements are presented.

a Methodology to Adapt Photogrammetric Models to Virtual Reality for Oculus Gear VR

NASA Astrophysics Data System (ADS)

Colmenero Fdez, A.

2017-11-01

In this paper, we will expose the process of adapting a high resolution model (laser and photogrammetry) into a virtual reality application for mobile phones. It is a virtual archeology project carried out on the site of Lugo's Mitreo, Spain.

Wave Processes in Arctic Seas, Observed from TerraSAR-X

DTIC Science & Technology

2015-09-30

Susanne Lehner German Aerospace Center Maritime Safety and Security Lab Henrich-Focke-Str. 4 28199 Bremen Germany phone: 0049 421/ 24420...of high resolution sea state forecast models in the German Bight, The International Archives of the Photogrammetry, Remote Sensing and Spatial

Remote Sensing Applications with High Reliability in Changjiang Water Resource Management

NASA Astrophysics Data System (ADS)

Ma, L.; Gao, S.; Yang, A.

2018-04-01

Remote sensing technology has been widely used in many fields. But most of the applications cannot get the information with high reliability and high accuracy in large scale, especially for the applications using automatic interpretation methods. We have designed an application-oriented technology system (PIR) composed of a series of accurate interpretation techniques,which can get over 85 % correctness in Water Resource Management from the view of photogrammetry and expert knowledge. The techniques compose of the spatial positioning techniques from the view of photogrammetry, the feature interpretation techniques from the view of expert knowledge, and the rationality analysis techniques from the view of data mining. Each interpreted polygon is accurate enough to be applied to the accuracy sensitive projects, such as the Three Gorge Project and the South - to - North Water Diversion Project. In this paper, we present several remote sensing applications with high reliability in Changjiang Water Resource Management,including water pollution investigation, illegal construction inspection, and water conservation monitoring, etc.

New Opportunities of Low-Cost Photogrammetry for Culture Heritage Preservation

NASA Astrophysics Data System (ADS)

Shults, R.

2017-05-01

In the paper, the questions of using the technologies of low-cost photogrammetry in combination with the additional capabilities of modern smartphones are considered. The research was carried out on the example of documenting the historical construction of the II World War - the Kiev Fortified Region. Brief historical information about the object of research is given. The possibilities of using modern smartphones as measuring instruments are considered. To get high-quality results, the camera of the smartphone was calibrated. The calibration results were used in the future to perform 3D modeling of defense facilities. Photographing of three defense structures in a different state: destroyed, partially destroyed and operating was carried out. Based on the results of photography using code targets, 3D object models were constructed. To verify the accuracy of the 3D modelling, control measurements of the lines between the code targets at the objects were performed. The obtained results are satisfying, and the technology considered in the paper can be recommended for use in performing archaeological and historical studies.

The Measurement Of Total Joint Loosening By X-Ray Photogrammetry

NASA Astrophysics Data System (ADS)

Lippert, Frederick G.; Veress, Sandor A.; Tiwari, Rama S.; Harrington, Richard M.

1980-07-01

Failure of total joint replacement due to loosening of the composents either between the implant and cement or between the cement and bone is emerging as a late complication with an incidence as high as 20 percent. Loosening may not only cause pain but progressive loss of support for the prosthesis with eventual structural failure. Early diagnosis is important so that revision may be carried when deterioration or pain occurs. No method is currently available which clearly establishes loosening at an early stage except surgical exploration. We have devised a method based on our in vivo photogrammetry studies of patellar tracking patterns using metallic markers placed in bone near both components of the total joint. Stereo x-rays taken with the joint loaded and unloaded are measured for relative motion between the implant and the metallic markers. Laboratory studies using prosthetic hip components mounted in plastic bone have revealed the ability of this method to detect pistoning movements as small as 80 microns. These findings were confirmed by physical measurements.

Comparison of Uas-Based Photogrammetry Software for 3d Point Cloud Generation: a Survey Over a Historical Site

NASA Astrophysics Data System (ADS)

Alidoost, F.; Arefi, H.

2017-11-01

Nowadays, Unmanned Aerial System (UAS)-based photogrammetry offers an affordable, fast and effective approach to real-time acquisition of high resolution geospatial information and automatic 3D modelling of objects for numerous applications such as topography mapping, 3D city modelling, orthophoto generation, and cultural heritages preservation. In this paper, the capability of four different state-of-the-art software packages as 3DSurvey, Agisoft Photoscan, Pix4Dmapper Pro and SURE is examined to generate high density point cloud as well as a Digital Surface Model (DSM) over a historical site. The main steps of this study are including: image acquisition, point cloud generation, and accuracy assessment. The overlapping images are first captured using a quadcopter and next are processed by different software to generate point clouds and DSMs. In order to evaluate the accuracy and quality of point clouds and DSMs, both visual and geometric assessments are carry out and the comparison results are reported.

Development of Uav Photogrammetry Method by Using Small Number of Vertical Images

NASA Astrophysics Data System (ADS)

Kunii, Y.

2018-05-01

This new and efficient photogrammetric method for unmanned aerial vehicles (UAVs) requires only a few images taken in the vertical direction at different altitudes. The method includes an original relative orientation procedure which can be applied to images captured along the vertical direction. The final orientation determines the absolute orientation for every parameter and is used for calculating the 3D coordinates of every measurement point. The measurement accuracy was checked at the UAV test site of the Japan Society for Photogrammetry and Remote Sensing. Five vertical images were taken at 70 to 90 m altitude. The 3D coordinates of the measurement points were calculated. The plane and height accuracies were ±0.093 m and ±0.166 m, respectively. These values are of higher accuracy than the results of the traditional photogrammetric method. The proposed method can measure 3D positions efficiently and would be a useful tool for construction and disaster sites and for other field surveying purposes.

Underwater Calibration of Dome Port Pressure Housings

NASA Astrophysics Data System (ADS)

Nocerino, E.; Menna, F.; Fassi, F.; Remondino, F.

2016-03-01

Underwater photogrammetry using consumer grade photographic equipment can be feasible for different applications, e.g. archaeology, biology, industrial inspections, etc. The use of a camera underwater can be very different from its terrestrial use due to the optical phenomena involved. The presence of the water and camera pressure housing in front of the camera act as additional optical elements. Spherical dome ports are difficult to manufacture and consequently expensive but at the same time they are the most useful for underwater photogrammetry as they keep the main geometric characteristics of the lens unchanged. Nevertheless, the manufacturing and alignment of dome port pressure housing components can be the source of unexpected changes of radial and decentring distortion, source of systematic errors that can influence the final 3D measurements. The paper provides a brief introduction of underwater optical phenomena involved in underwater photography, then presents the main differences between flat and dome ports to finally discuss the effect of manufacturing on 3D measurements in two case studies.

Measurement of compressed breast thickness by optical stereoscopic photogrammetry.

PubMed

Tyson, Albert H; Mawdsley, Gordon E; Yaffe, Martin J

2009-02-01

The determination of volumetric breast density (VBD) from mammograms requires accurate knowledge of the thickness of the compressed breast. In attempting to accurately determine VBD from images obtained on conventional mammography systems, the authors found that the thickness reported by a number of mammography systems in the field varied by as much as 15 mm when compressing the same breast or phantom. In order to evaluate the behavior of mammographic compression systems and to be able to predict the thickness at different locations in the breast on patients, they have developed a method for measuring the local thickness of the breast at all points of contact with the compression paddle using optical stereoscopic photogrammetry. On both flat (solid) and compressible phantoms, the measurements were accurate to better than 1 mm with a precision of 0.2 mm. In a pilot study, this method was used to measure thickness on 108 volunteers who were undergoing mammography examination. This measurement tool will allow us to characterize paddle surface deformations, deflections and calibration offsets for mammographic units.

Portable Imagery Quality Assessment Test Field for Uav Sensors

NASA Astrophysics Data System (ADS)

Dąbrowski, R.; Jenerowicz, A.

2015-08-01

Nowadays the imagery data acquired from UAV sensors are the main source of all data used in various remote sensing applications, photogrammetry projects and in imagery intelligence (IMINT) as well as in other tasks as decision support. Therefore quality assessment of such imagery is an important task. The research team from Military University of Technology, Faculty of Civil Engineering and Geodesy, Geodesy Institute, Department of Remote Sensing and Photogrammetry has designed and prepared special test field- The Portable Imagery Quality Assessment Test Field (PIQuAT) that provides quality assessment in field conditions of images obtained with sensors mounted on UAVs. The PIQuAT consists of 6 individual segments, when combined allow for determine radiometric, spectral and spatial resolution of images acquired from UAVs. All segments of the PIQuAT can be used together in various configurations or independently. All elements of The Portable Imagery Quality Assessment Test Field were tested in laboratory conditions in terms of their radiometry and spectral reflectance characteristics.

Apollo Video Photogrammetry Estimation Of Plume Impingement Effects

NASA Technical Reports Server (NTRS)

Immer, Christopher; Lane, John; Metzger, Philip T.; Clements, Sandra

2008-01-01

The Constellation Project's planned return to the moon requires numerous landings at the same site. Since the top few centimeters are loosely packed regolith, plume impingement from the Lander ejects the granular material at high velocities. Much work is needed to understand the physics of plume impingement during landing in order to protect hardware surrounding the landing sites. While mostly qualitative in nature, the Apollo Lunar Module landing videos can provide a wealth of quantitative information using modem photogrammetry techniques. The authors have used the digitized videos to quantify plume impingement effects of the landing exhaust on the lunar surface. The dust ejection angle from the plume is estimated at 1-3 degrees. The lofted particle density is estimated at 10(exp 8)- 10(exp 13) particles per cubic meter. Additionally, evidence for ejection of large 10-15 cm sized objects and a dependence of ejection angle on thrust are presented. Further work is ongoing to continue quantitative analysis of the landing videos.

E-Learning - best Practice in Photogrammetry, Remote Sensing and GIS - Status and Challenges

NASA Astrophysics Data System (ADS)

König, G.; Shih, P. T. Y.; Katterfeld, C.

2012-07-01

In addition to professional training, computer aided teaching has long tradition. The difficult economic situation, however, forced many customers to take drastic austerity measures in the field of learning. Cost pressure encouraged a new openness to innovative and tailored learning concepts. As a result e-learning gained more interest and importance promising great benefit to the user. Around the world a variety of well-designed e-learning products exist. The web pages of Commission VI/2 (http://www.igg.tuberlin. de/ISPRS/) provide a decision aid to locate relevant material. Links to websites known to the authors are listed; a search function allows selective access, taking account of quality criteria. This article describes best practice e-learning applications in photogrammetry, remote sensing and GIS. The rating is based on results of the Computer Assisted Teaching CONtest (CATCON) initiated by ISPRS, and on observation of recent developments.

A minimally invasive technique to assess several life-history characteristics of the endangered great hammerhead shark Sphyrna mokarran.

PubMed

O'Connell, C P; Leurs, G

2016-03-01

A dorsal-fin photo-identification technique paired with a non-invasive parallel laser photogrammetry technique was used to non-invasively identify individual Sphyrna mokarran over time. Based on the data collected over a duration of 59 days, 16 different S. mokarran (mean ± S.D. pre-caudal length: 220·82 ± 13·66 cm; mean ± S.D. cephalofoil width: 71·38 ± 7·94 cm) were identified using dorsal-fin photo-identification, with a mean ± S.D. shark re-sighting frequency of 4·05 ± 3·06 at-sea days. The results illustrate a high S. mokarran sighting rate and therefore, the utilization of parallel laser photogrammetry and dorsal-fin photo-identification may be a plausible multi-year approach to aid in non-invasively determining the growth rate and inter-annual site fidelity of these animals. © 2016 The Fisheries Society of the British Isles.

Photogrammetry for Archaeology: Collecting Pieces Together

NASA Astrophysics Data System (ADS)

Chibunichev, A. G.; Knyaz, V. A.; Zhuravlev, D. V.; Kurkov, V. M.

2018-05-01

The complexity of retrieving and understanding the archaeological data requires to apply different techniques, tools and sensors for information gathering, processing and documenting. Archaeological research now has the interdisciplinary nature involving technologies based on different physical principles for retrieving information about archaeological findings. The important part of archaeological data is visual and spatial information which allows reconstructing the appearance of the findings and relation between them. Photogrammetry has a great potential for accurate acquiring of spatial and visual data of different scale and resolution allowing to create archaeological documents of new type and quality. The aim of the presented study is to develop an approach for creating new forms of archaeological documents, a pipeline for their producing and collecting in one holistic model, describing an archaeological site. A set of techniques is developed for acquiring and integration of spatial and visual data of different level of details. The application of the developed techniques is demonstrated for documenting of Bosporus archaeological expedition of Russian State Historical Museum.

Sand mining impacts on long-term dune erosion in southern Monterey Bay

USGS Publications Warehouse

Thornton, E.B.; Sallenger, Abby; Sesto, Juan Conforto; Egley, L.; McGee, Timothy; Parsons, Rost

2006-01-01

Southern Monterey Bay was the most intensively mined shoreline (with sand removed directly from the surf zone) in the U.S. during the period from 1906 until 1990, when the mines were closed following hypotheses that the mining caused coastal erosion. It is estimated that the yearly averaged amount of mined sand between 1940 and 1984 was 128,000 m3/yr, which is approximately 50% of the yearly average dune volume loss during this period. To assess the impact of sand mining, erosion rates along an 18 km range of shoreline during the times of intensive sand mining (1940–1990) are compared with the rates after sand mining ceased (1990–2004). Most of the shoreline is composed of unconsolidated sand with extensive sand dunes rising up to a height of 46 m, vulnerable to the erosive forces of storm waves. Erosion is defined here as a recession of the top edge of the dune. Recession was determined using stereo-photogrammetry, and LIDAR and GPS surveys. Long-term erosion rates vary from about 0.5 m/yr at Monterey to 1.5 m/yr in the middle of the range, and then decrease northward. Erosion events are episodic and occur when storm waves and high tides coincide, allowing swash to undercut the dune and resulting in permanent recession. Erosion appears to be correlated with the occurrence of El Niños. The calculated volume loss of the dune in southern Monterey Bay during the 1997–98 El Niño winter was 1,820,000 m3, which is almost seven times the historical annual mean dune erosion of 270,000 m3/yr. The alongshore variation in recession rates appears to be a function of the alongshore gradient in mean wave energy and depletions by sand mining. After cessation of sand mining in 1990, the erosion rates decreased at locations in the southern end of the bay but have not significantly changed at other locations.

Multidisciplinary approach for the characterization of landslides in volcanic areas - a case study from the Palma Sola-Chiconquiaco Mountain Range, Mexico

NASA Astrophysics Data System (ADS)

Wilde, Martina; Rodríguez Elizarrarás, Sergio R.; Morales Barrera, Wendy V.; Schwindt, Daniel; Bücker, Matthias; Flores Orozco, Adrián; García García, Emilio; Pita de la Paz, Carlos; Terhorst, Birgit

2017-04-01

The Palma Sola-Chiconquiaco mountain range, situated in the State of Veracruz, Mexico, is highly susceptible to landslides, which is evidenced by the high frequency of landslide events of different sizes. The study area is located near the Gulf of Mexico coastline in the eastern sector of the Trans Mexican Volcanic Belt. There, landslide triggers are intense rainfalls related to tropical storms and hurricanes. Steeper slopes are commonly affected by rockfalls, whereas moderate slopes, covered by massive slope deposits, are affected by shallow as well as deep seated landslides. Some of the landslides in the slope deposits reach dimensions of more than 1000 m in length and depths of over 30 m. The heterogeneous parent material as well as older slide masses hamper the detailed characterization of the involved materials. Therefore, in this study, a multidisciplinary approach is applied that integrates geomorphological, geological, and geophysical data. The aim is the reconstruction of process dynamics by analyzing the geomorphological situation and subsurface conditions before and after the event. The focus lies on the identification of past landslide areas, which represent areas with high susceptibility for the reactivation of old slide masses. Furthermore, the analysis of digital terrain models, generated before the landslide event, indicate initial movements like extension cracks, which are located close to the current scarp area. In order to characterize the subsurface of slide masses geophysical investigations are applied. The geophysical survey consists of a total of nine profiles covering relevant key features of the large affected area. Along these profiles, electrical resistivity tomography (ERT) and seismic refraction tomography (SRT) data were collected. Both, electrical and seismic images reveal a sharp contrast between relatively loose and dry material of the slide mass (high resistivities and low seismic velocities) and the former land surface that is characterized by significantly reduced resistivities and higher seismic velocities. This contrast allows to establish the thicknesses of slope deposits and geological layers along all geophysical profiles. Furthermore, the investigations are complemented by a high resolution digital terrain model of the landslide and its surroundings, which was reconstructed from orthophotos derived from unmanned aerial vehicle photogrammetry.

2006, REMOTE SENSING AND GIS IN THE REMEDIATION OF CHEMICAL WEAPONS CONTAMINATION IN AN URBAN LANDSCAPE

EPA Science Inventory

This presentation will document the use of historical imagery, GIS, photogrammetry and hyperspectral remote sensing in locating and removing chemical weapons such as Mustard Gas, Phosgene, Ricin, and Lewisite from the environment and establishing a risk assessment methodology for...

Comparison of 3D point clouds produced by LIDAR and UAV photoscan in the Rochefort cave (Belgium)

NASA Astrophysics Data System (ADS)

Watlet, Arnaud; Triantafyllou, Antoine; Kaufmann, Olivier; Le Mouelic, Stéphane

2016-04-01

Amongst today's techniques that are able to produce 3D point clouds, LIDAR and UAV (Unmanned Aerial Vehicle) photogrammetry are probably the most commonly used. Both methods have their own advantages and limitations. LIDAR scans create high resolution and high precision 3D point clouds, but such methods are generally costly, especially for sporadic surveys. Compared to LIDAR, UAV (e.g. drones) are cheap and flexible to use in different kind of environments. Moreover, the photogrammetric processing workflow of digital images taken with UAV becomes easier with the rise of many affordable software packages (e.g. Agisoft, PhotoModeler3D, VisualSFM). We present here a challenging study made at the Rochefort Cave Laboratory (South Belgium) comprising surface and underground surveys. The site is located in the Belgian Variscan fold-and-thrust belt, a region that shows many karstic networks within Devonian limestone units. A LIDAR scan has been acquired in the main chamber of the cave (~ 15000 m³) to spatialize 3D point cloud of its inner walls and infer geological beds and structures. Even if the use of LIDAR instrument was not really comfortable in such caving environment, the collected data showed a remarkable precision according to few control points geometry. We also decided to perform another challenging survey of the same cave chamber by modelling a 3D point cloud using photogrammetry of a set of DSLR camera pictures taken from the ground and UAV pictures. The aim was to compare both techniques in terms of (i) implementation of data acquisition and processing, (ii) quality of resulting 3D points clouds (points density, field vs cloud recovery and points precision), (iii) their application for geological purposes. Through Rochefort case study, main conclusions are that LIDAR technique provides higher density point clouds with slightly higher precision than photogrammetry method. However, 3D data modeled by photogrammetry provide visible light spectral information for each modeled voxel and interpolated vertices that can be a useful attributes for clustering during data treatment. We thus illustrate such applications to the Rochefort cave by using both sources of 3D information to quantify the orientation of inaccessible geological structures (e.g. faults, tectonic and gravitational joints, and sediments bedding), cluster these structures using color information gathered from UAV's 3D point cloud and compare these data to structural data surveyed on the field. An additional drone photoscan was also conducted in the surface sinkhole giving access to the surveyed underground cavity to seek geological bodies' connections.

The XII Century Towers, a Benchmark of the Rome Countryside almost Cancelled: the Safeguard Plan by Low Cost Uav and Terrestrial Dsm Photogrammetry Surveying and 3d Web GIS Applications

NASA Astrophysics Data System (ADS)

Barelli, L.; Paolini, P.; Forti, G.

2017-11-01

"Giving a bird-fly look at the Rome countryside, throughout the Middle Age central period, it would show as if the multiple city towers has been widely spread around the territory" on a radial range of maximum thirty kilometers far from the Capitol Hill center (Carocci and Vendittelli, 2004). This is the consequence of the phenomenon identified with the "Incasalamento" neologism, described in depth in the following paper, intended as the general process of expansion of the urban society interests outside the downtown limits, started from the half of the XII and developed through all the XIII century, slowing down and ending in the following years. From the XIX century till today the architectural finds of this reality have raised the interest of many national and international scientists, which aimed to study and catalog them all to create a complete framework that, cause of its extension, didn't allow yet attempting any element by element detailed analysis. From the described situation has started our plan of intervention, we will apply integrated survey methods and technologies of terrestrial and UAV near stereo-photogrammetry, by the use of low cost drones, more than action cameras and reflex on extensible rods, integrated and referenced with GPS and topographic survey. In the final project we intend to produce some 3D scaled and textured surface models of any artifact (almost two hundreds were firstly observed still standing), to singularly study the dimensions and structure, to analyze the building materials and details and to formulate an hypothesis about any function, based even on the position along the territory. These models, successively georeferenced, will be imported into a 2D and 3D WebGIS and organized in layers made visible on basemaps of reference, as much as on historical maps.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheung, Y; Rahimi, A; Sawant, A

Purpose: Active breathing control (ABC) has been used to reduce treatment margin due to respiratory organ motion by enforcing temporary breath-holds. However, in practice, even if the ABC device indicates constant lung volume during breath-hold, the patient may still exhibit minor chest motion. Consequently, therapists are given a false sense of security that the patient is immobilized. This study aims at quantifying such motion during ABC breath-holds by monitoring the patient chest motion using a surface photogrammetry system, VisionRT. Methods: A female patient with breast cancer was selected to evaluate chest motion during ABC breath-holds. During the entire course ofmore » treatment, the patient’s chest surface was monitored by a surface photogrammetry system, VisionRT. Specifically, a user-defined region-of-interest (ROI) on the chest surface was selected for the system to track at a rate of ∼3Hz. The surface motion was estimated by rigid image registration between the current ROI image captured and a reference image. The translational and rotational displacements computed were saved in a log file. Results: A total of 20 fractions of radiation treatment were monitored by VisionRT. After removing noisy data, we obtained chest motion of 79 breath-hold sessions. Mean chest motion in AP direction during breath-holds is 1.31mm with 0.62mm standard deviation. Of the 79 sessions, the patient exhibited motion ranging from 0–1 mm (30 sessions), 1–2 mm (37 sessions), 2–3 mm (11 sessions) and >3 mm (1 session). Conclusion: Contrary to popular assumptions, the patient is not completely still during ABC breath-hold sessions. In this particular case studied, the patient exhibited chest motion over 2mm in 14 out of 79 breath-holds. Underestimating treatment margin for radiation therapy with ABC could reduce treatment effectiveness due to geometric miss or overdose of critical organs. The senior author receives research funding from NIH, VisionRT, Varian Medical Systems and Elekta.« less

Use of photogrammetry as a tool for accident investigation and reconstruction : a review of the literature and state of the practice.

DOT National Transportation Integrated Search

2007-01-01

One of the key goals of incident management is the rapid clearance of traffic incidents. Many transportation agencies focus their incident management on quicker and more reliable detection techniques. Another focus, however, should be the reduction i...

75 FR 43150 - Marine Mammals; File Nos. 10018, 13846, 14451, 14585, 14599, 14122, 14296, and 14353

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-23

... of sloughed skin, photogrammetry, biopsy sampling, playback experiments, and/or suction- cup and... to individuals; (6) attachment of suction cup tags; (7) SCUBA observations; and (8) opportunistic.... Research will include vessel-based approaches: (1) to humpback whales for biological sampling, suction cup...