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Sample records for histology-equivalent sectioning laser-scanning

  1. Handheld histology-equivalent sectioning laser-scanning confocal optical microscope for interventional imaging.

    PubMed

    Kumar, Karthik; Avritscher, Rony; Wang, Youmin; Lane, Nancy; Madoff, David C; Yu, Tse-Kuan; Uhr, Jonathan W; Zhang, Xiaojing

    2010-04-01

    A handheld, forward-imaging, laser-scanning confocal microscope (LSCM) demonstrating optical sectioning comparable with microtome slice thicknesses in conventional histology, targeted towards interventional imaging, is reported. Fast raster scanning (approximately 2.5 kHz line scan rate, 3.0-5.0 frames per second) was provided by a 2-axis microelectromechanical system (MEMS) scanning mirror fabricated by a method compatible with complementary metal-oxide-semiconductor (CMOS) processing. Cost-effective rapid-prototyped packaging combined the MEMS mirror with micro-optical components into a probe with 18 mm outer diameter and 54 mm rigid length. ZEMAX optical design simulations indicate the ability of the handheld optical system to obtain lateral resolution of 0.31 and axial resolution of 2.85 microm. Lateral and axial resolutions are experimentally measured at 0.5 microm and 4.2 microm respectively, with field of view of 200 x 125 microm. Results of reflectance imaging of ex vivo swine liver, and fluorescence imaging of the expression of cytokeratin and mammaglobin tumor biomarkers in epithelial human breast tissue from metastatic breast cancer patients are presented. The results indicate that inexpensive, portable handheld optical microscopy tools based on silicon micromirror technologies could be important in interventional imaging, complementing existing coarse-resolution techniques to improve the efficacy of disease diagnosis, image-guided excisional microsurgery, and monitored photodynamic therapy. PMID:20012209

  2. Multicolor immunophenotyping of tissue sections by laser scanning cytometry (LSC)

    NASA Astrophysics Data System (ADS)

    Tarnok, Attila; Gerstner, Andreas O.; Lenz, Dominik; Osmancik, Pavel; Schneider, Peter; Trumpfheller, Christine; Racz, Pal; Tenner-Racz, Klara

    2002-05-01

    In lymphatic organs the quantitative analysis of the spatial distribution of leukocytes would give relevant information about alterations during diseases (leukemia, HIV, AIDS) and their therapeutic regimen. Analysis of them in solid tissues is difficult to perform but would yield important data in a variety of clinical and experimental settings. We have developed an automated analysis method for LSC suitable for archived or fresh biopsy material of human lymph nodes and tonsils. Sections are stained with PI for DNA and up to three antigens using direct or indirect immunofluorescence staining. Measurement is triggered on DNA-fluorescence (Argon Laser). Due to the heterogeneity in cell density measurements are repeatedly performed at different threshold levels (low threshold: regions of low cellular density, germinal centers; high threshold: dense regions, mantle zone). Data are acquired by single- (Ar) or dual-laser excitation (Ar-HeNe) in order to determine data from single- (FITC), up to triple-staining (FITC/PE-Cy5/APC). Percentage and cellular density of cell-subsets is quantified in different structural regions of the specimen. Comparison with manual analysis of identical specimens showed very good correlation. With LSC a semi-automated operator-independent and immunophenotyping of lymphatic tissues with simultaneously up to four antibodies is possible. This technique should yield new insight into processes during diseases and should help to quantify the success of therapeutic interventions.

  3. Laser scanning confocal microscopy: history, applications, and related optical sectioning techniques.

    PubMed

    Paddock, Stephen W; Eliceiri, Kevin W

    2014-01-01

    Confocal microscopy is an established light microscopical technique for imaging fluorescently labeled specimens with significant three-dimensional structure. Applications of confocal microscopy in the biomedical sciences include the imaging of the spatial distribution of macromolecules in either fixed or living cells, the automated collection of 3D data, the imaging of multiple labeled specimens and the measurement of physiological events in living cells. The laser scanning confocal microscope continues to be chosen for most routine work although a number of instruments have been developed for more specific applications. Significant improvements have been made to all areas of the confocal approach, not only to the instruments themselves, but also to the protocols of specimen preparation, to the analysis, the display, the reproduction, sharing and management of confocal images using bioinformatics techniques. PMID:24052346

  4. Shipborne hydrographic laser scanning

    NASA Astrophysics Data System (ADS)

    Pfennigbauer, Martin; Rieger, Peter; Schaich, Martin

    2011-11-01

    Applications like hydro-archeology, hydrobiology, or hydraulic engineering sometimes require accurate surveying of submerged areas with point densities usually only achieved with mobile or terrestrial laser scanning. For navigable waterbodies, hydrographic laser scanning from a floating platform represents a viable solution. RIEGL's new hydrographic laser scanner VQ-820-G with its exceptionally high measurement rate of up to 110,000 net measurements per second and its small laser footprint is optimally suited for such applications. We present results from a measurement campaign surveying prehistoric lake dwellings at Lake Constance in Germany. While the aim of typical hydrographic laser scanning applications is to roughly acquire the ground's shape and structure, in this case it was tried to determine the exact position, shape, and attitude of the remainders of the piles. The special requirements with respect to mission planning and data processing are discussed and the performance of the laser scanner is assessed.

  5. Laser Scanning In Inspection

    NASA Astrophysics Data System (ADS)

    West, Patricia; Baker, Lionel R.

    1989-03-01

    This paper is a review of the applications of laser scanning in inspection. The reasons for the choice of a laser in flying spot scanning and the optical properties of a laser beam which are of value in a scanning instrument will be given. The many methods of scanning laser beams in both one and two dimensions will be described. The use of one dimensional laser scanners for automatic surface inspection for transmitting and reflective products will be covered in detail, with particular emphasis on light collection techniques. On-line inspection applications which will be mentioned include: photographic film web, metal strip products, paper web, glass sheet, car body paint surfaces and internal cylinder bores. Two dimensional laser scanning is employed in applications where increased resolution, increased depth of focus, and better contrast are required compared with conventional vidicon TV or solid state array cameras. Such examples as special microscope laser scanning systems and a TV compatible system for use in restricted areas of a nuclear reactor will be described. The technical and economic benefits and limitations of laser scanning video systems will be compared with conventional TV and CCD array devices.

  6. In vivo imaging flow cytometry based on laser scanning two-photon microscopy at kHz cross-sectional frame rate

    NASA Astrophysics Data System (ADS)

    Kong, Lingjie; Tang, Jianyong; Cui, Meng

    2016-03-01

    In vivo flow cytometry has found numerous applications in biology and pharmacology. However, conventional cytometry does not provide the detailed morphological information that is needed to fully determine the phenotype of individual circulating cells. Imaging cytometry, capable of visualizing the morphology and dynamics of the circulating cells at high spatiotemporal resolution, is highly desired. Current wide-field based image cytometers are limited in the imaging depth and provide only two-dimensional resolution. For deep tissue imaging, laser scanning two-photon fluorescence microscopy (TPM) is widely adopted. However, for applications in flow cytometry, the axial scanning speed of current TPMs is inadequate to provide high-speed cross-sectional imaging of vasculature. We have integrated an optical phase-locked ultrasound lens into a standard TPM and achieved microsecond-scale axial scanning. With a galvo scanner for transverse scanning, we achieved kHz cross-sectional frame rate. Here we report its applications for in vivo deformability cytometry and in vivo imaging flow cytometry, and demonstrate the capability of imaging dynamical morphologies of flowing cells, distinguishing cells and cellular clusters, and simultaneously quantifying different cell populations based on their fluorescent labels.

  7. Hyperchromatic laser scanning cytometry

    NASA Astrophysics Data System (ADS)

    Tárnok, Attila; Mittag, Anja

    2007-02-01

    In the emerging fields of high-content and high-throughput single cell analysis for Systems Biology and Cytomics multi- and polychromatic analysis of biological specimens has become increasingly important. Combining different technologies and staining methods polychromatic analysis (i.e. using 8 or more fluorescent colors at a time) can be pushed forward to measure anything stainable in a cell, an approach termed hyperchromatic cytometry. For cytometric cell analysis microscope based Slide Based Cytometry (SBC) technologies are ideal as, unlike flow cytometry, they are non-consumptive, i.e. the analyzed sample is fixed on the slide. Based on the feature of relocation identical cells can be subsequently reanalyzed. In this manner data on the single cell level after manipulation steps can be collected. In this overview various components for hyperchromatic cytometry are demonstrated for a SBC instrument, the Laser Scanning Cytometer (Compucyte Corp., Cambridge, MA): 1) polychromatic cytometry, 2) iterative restaining (using the same fluorochrome for restaining and subsequent reanalysis), 3) differential photobleaching (differentiating fluorochromes by their different photostability), 4) photoactivation (activating fluorescent nanoparticles or photocaged dyes), and 5) photodestruction (destruction of FRET dyes). With the intelligent combination of several of these techniques hyperchromatic cytometry allows to quantify and analyze virtually all components of relevance on the identical cell. The combination of high-throughput and high-content SBC analysis with high-resolution confocal imaging allows clear verification of phenotypically distinct subpopulations of cells with structural information. The information gained per specimen is only limited by the number of available antibodies and by sterical hindrance.

  8. Laser Scanning Applications in Fluvial Geomorphology

    NASA Astrophysics Data System (ADS)

    Alho, P.

    2014-12-01

    During recent decades, the use of high-resolution laser scanning data in fluvial studies has rapidly increased. Airborne laser scanning (ALS) can be used to extensively map riverine topography. Laser scanning data have great potential to improve the effectiveness of topographical data acquisition and the accuracy and resolution of DTMs (Digital Terrain Models) needed in fluvial geomorphology. Airborne Laser Scanning (ALS) is applicable for mapping areas varying from reach to catchment scale and these data are, therefore, particularly suitable, especially for hydraulic modelling, mapping of flood inundation, and the detection of macro-scale fluvial geomorphology. With Terrestrial Laser Scanning (TLS) a spatial resolution of less than 1 mm and a range accuracy of few millimetres can be achieved. Mobile Laser Scanning (MLS) enables a remarkably faster survey approach compared to the conventional TLS method. One of the newest applications of MLS approaches involves a boat/cart/backpack -based mobile mapping system. This set-up includes laser scanning and imaging from a platform moving along a river course or floodplain and may be used to expand the spatial extent of terrestrial scanning. Detailed DTMs derived from laser scanning data can be used to improve the recognition of fluvial landforms, the geometric data of hydraulic modelling, and the estimation of flood inundation extents and the associated fluvial processes. Fluvial environments also offer challenges for the application of laser scanning techniques. Factors such as vegetation cover, terrain undulation, coarse surface materials and water surfaces may distort a laser scanning survey.

  9. Street-Scene Tree Segmentation from Mobile Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Guan, H.; Cao, S.; Yu, Y.; Li, J.; Liu, N.; Chen, P.; Li, Y.

    2016-06-01

    Our work addresses the problem of extracting trees from mobile laser scanning data. The work is a two step-wise strategy, including terrain point removal and tree segmentation. First, a voxel-based upward growing filtering is proposed to remove terrain points from the mobile laser scanning data. Then, a tree segmentation is presented to extract individual trees via a Euclidean distance clustering approach and Voxel-based Normalized Cut (VNCut) segmentation approach. A road section data acquired by a RIEGL VMX-450 system are selected for evaluating the proposed tree segmentation method. Qualitative analysis shows that our algorithm achieves a good performance.

  10. A New Multichannel Spectral Imaging Laser Scanning Confocal Microscope

    PubMed Central

    Zhang, Yunhai; Hu, Bian; Dai, Yakang; Yang, Haomin; Huang, Wei; Xue, Xiaojun; Li, Fazhi; Zhang, Xin; Jiang, Chenyu; Gao, Fei; Chang, Jian

    2013-01-01

    We have developed a new multichannel spectral imaging laser scanning confocal microscope for effective detection of multiple fluorescent labeling in the research of biological tissues. In this paper, the design and key technologies of the system are introduced. Representative results on confocal imaging, 3-dimensional sectioning imaging, and spectral imaging are demonstrated. The results indicated that the system is applicable to multiple fluorescent labeling in biological experiments. PMID:23585775

  11. Multiplatform Mobile Laser Scanning: Usability and Performance

    PubMed Central

    Kukko, Antero; Kaartinen, Harri; Hyyppä, Juha; Chen, Yuwei

    2012-01-01

    Mobile laser scanning is an emerging technology capable of capturing three-dimensional data from surrounding objects. With state-of-the-art sensors, the achieved point clouds capture object details with good accuracy and precision. Many of the applications involve civil engineering in urban areas, as well as traffic and other urban planning, all of which serve to make 3D city modeling probably the fastest growing market segment in this field. This article outlines multiplatform mobile laser scanning solutions such as vehicle- and trolley-operated urban area data acquisition, and boat-mounted equipment for fluvial environments. Moreover, we introduce a novel backpack version of mobile laser scanning equipment for surveying applications in the field of natural sciences where the requirements include precision and mobility in variable terrain conditions. In addition to presenting a technical description of the systems, we discuss the performance of the solutions in the light of various applications in the fields of urban mapping and modeling, fluvial geomorphology, snow-cover characterization, precision agriculture, and in monitoring the effects of climate change on permafrost landforms. The data performance of the mobile laser scanning approach is described by the results of an evaluation of the ROAMER on a permanent MLS test field. Furthermore, an in situ accuracy assessment using a field of spherical 3D targets for the newly-introduced Akhka backpack system is conducted and reported on.

  12. Laser scan microscope and infrared laser scan microcope: two important tools for device testing

    NASA Astrophysics Data System (ADS)

    Ziegler, Eberhard

    1991-03-01

    The optical beam induced current (OBIC) produced in devices by a laser scan microscope (LSM) is used to localize hot spots, leakage currents, electrostatic discharge defects and weak points. The LSM also allows photoluminescence measurements with high spatial and energy resolution. Using the infrared laser scan microscope (IR LSM), defects in the metallization and latch-up sensitive region could be detected from the back of the device.

  13. The design of laser scanning galvanometer system

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoling; Zhou, Bin; Xie, Weihao; Zhang, Yuangeng

    2015-02-01

    In this paper, we designed the laser scanning galvanometer system according to our requirements. Based on scanning range of our laser scanning galvanometer system, the design parameters of this system were optimized. During this work, we focused on the design of the f-θ field lens. An optical system of patent lens in the optical manual book, which had three glasses structure, was used in our designs. Combining the aberration theory, the aberration corrections and image quality evaluations were finished using Code V optical design software. An optimum f-θ field lens was designed, which had focal length of 434 mm, pupil diameter of 30 mm, scanning range of 160 mm × 160 mm, and half field angle of 18°×18°. At the last, we studied the influences of temperature changes on our system.

  14. Multiplatform Approach to Mobile Laser Scanning

    NASA Astrophysics Data System (ADS)

    Kukko, A.; Kaartinen, H.; Hyyppä, J.; Chen, Y.

    2012-07-01

    Mobile laser scanning is an emerging technology for capturing three-dimensional information from the surrounding objects. With state of the art sensors the achieved point cloud could capture fine details of the surroundings with good accuracy and effectiveness. Many of the applications deal with the civil engineering purposes in urban areas for traffic and city planning and modelling. In this article we present multiplatform mobile laser scanning solutions for mapping applications that require mobility in various terrains and river environments but yet produce high density point clouds with good reliability and accuracy. The ROAMER mobile laser scanning system was deployed in multitude of tasks from urban areas to climate research. The paper also introduces a completely new backpack Akhka platform for mobile lidar mapping of areas where wheeled vehicles cannot operate. The sensor set is the same in all of the approaches, but the carrying vessel was selected according to the application. This was possible thanks to a relatively light and compact yet simple design of the system. ROAMER system is one of the few high-end MLS systems that are easily adaptable to various platforms. In addition to technical description of the system we discuss the practical performance of the solutions through various applications in the fields of urban mapping, fluvial geomorphology, snow cover characterization and climate change monitoring.

  15. Photodynamic therapy with laser scanning mode of tumor irradiation

    NASA Astrophysics Data System (ADS)

    Chepurna, Oksana; Shton, Irina; Kholin, Vladimir; Voytsehovich, Valerii; Popov, Viacheslav; Pavlov, Sergii; Gamaleia, Nikolai; Wójcik, Waldemar; Zhassandykyzy, Maral

    2015-12-01

    In this study we propose a new version of photodynamic therapy performed by laser scanning. The method consists in tumor treatment by a light beam of a small cross section which incrementally moves through the chosen area with a defined delay at each point and repetitively re-scans a zone starting from the initial position. Experimental evaluation of the method in vitro on murine tumor model showed that despite the dose, applied by scanning irradiation mode, was 400 times lower, the tumor inhibition rate conceded to attained with continuous irradiation mode by only 20%.

  16. Mobile Laser Scanning for Indoor Modelling

    NASA Astrophysics Data System (ADS)

    Thomson, C.; Apostolopoulos, G.; Backes, D.; Boehm, J.

    2013-10-01

    The process of capturing and modelling buildings has gained increased focus in recent years with the rise of Building Information Modelling (BIM). At the heart of BIM is a process change for the construction and facilities management industries whereby a BIM aids more collaborative working through better information exchange, and as a part of the process Geomatic/Land Surveyors are not immune from the changes. Terrestrial laser scanning has been proscribed as the preferred method for rapidly capturing buildings for BIM geometry. This is a process change from a traditional measured building survey just with a total station and is aided by the increasing acceptance of point cloud data being integrated with parametric building models in BIM tools such as Autodesk Revit or Bentley Architecture. Pilot projects carried out previously by the authors to investigate the geometry capture and modelling of BIM confirmed the view of others that the process of data capture with static laser scan setups is slow and very involved requiring at least two people for efficiency. Indoor Mobile Mapping Systems (IMMS) present a possible solution to these issues especially in time saved. Therefore this paper investigates their application as a capture device for BIM geometry creation over traditional static methods through a fit-for-purpose test.

  17. Two-Photon Laser Scanning Microscopy

    NASA Astrophysics Data System (ADS)

    Nimmerjahn, A.; Theer, P.; Helmchen, F.

    Since its inception more than 15 years ago, two-photon laser scanning microscopy (2PLSM) has found widespread use in biological and medical research. Two-photon microscopy is based on simultaneous absorption of two photons by fluorophores and subsequent fluorescence emission, a process which under normal illumination conditions is highly improbable. Theoretically described around 1930 by Maria Göppert-Mayer [1], the first experimental demonstration of two-photon excitation had to await the invention of the laser, which produced sufficiently high light intensities to observe two-photon absorption events [2]. Only after the development of ultrafast lasers providing subpicosecond light pulses with high peak power intensities, however, two-photon-excited fluorescence became practical in a laser-scanning microscope [3]. Since then 2PLSM has developed into the method of choice for high-resolution imaging in living animals (reviewed in [4,5]). One of the main reasons is the low sensitivity of 2PLSM to light scattering, which enables imaging relatively deep inside biological tissue and direct observation of the dynamic behavior of cells in their native environment. In this chapter, we introduce the physical principles governing 2PLSM and briefly describe the key instrument components. We give an overview of fluorescence labeling techniques and how they are combined with 2PLSM for functional imaging and photomanipulation in living tissue. Finally, we discuss limitations and provide some future perspectives.

  18. Extraction of power lines from mobile laser scanning data

    NASA Astrophysics Data System (ADS)

    Xiang, Qing; Li, Jonathan; Wen, Chenglu; Huang, Pengdi

    2016-03-01

    Modern urban life is becoming increasingly more dependent on reliable electric power supply. Since power outages cause substantial financial losses to producers, distributors and consumers of electric power, it is in the common interest to minimize failures of power lines. In order to detect defects as early as possible and to plan efficiently the maintenance activities, distribution networks are regularly inspected. Carrying out foot patrols or climbing the structures to visually inspect transmission lines and aerial surveys (e.g., digital imaging or most recent airborne laser scanning (ALS) are the two most commonly used methods of power line inspection. Although much faster in comparison to the foot patrol inspection, aerial inspection is more expensive and usually less accurate, in complex urban areas particularly. This paper presents a scientific work that is done in the use of mobile laser scanning (MLS) point clouds for automated extraction of power lines. In the proposed method, 2D power lines are extracted using Hough transform in the projected XOY plane and the 3D power line points are visualized after the point searching. Filtering based on an elevation threshold is applied, which is combined with the vehicle's trajectory in the horizontal section.

  19. Estimates of slope erosion intensity utilizing terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Usmanov, B.; Yermolaev, O.; Gafurov, A.

    2015-03-01

    Despite the large variety of methods for estimating slope erosion intensity, it is still difficult to obtain accurate erosion rates. Therefore, our goal was to develop a method to provide accurate estimates of sheet and rill erosion intensities, and evaluate denudation quantities due to abrasion, landslides and talus processes using a high-precision laser scanning system (Trimble® GX). Differential maps between all stages of surveying and TIN-models were built directly on point clouds in "Trimble® RealWorks" software. Inspection and cross-section tools were used for detailed study of ground movements on the slope surface and the development of linear erosion forms. A new method for accurate estimates of the erosion has been developed using terrestrial laser scanning techniques. It makes it possible to assess the denudation-accumulation balance on erosive slopes, determine the dynamics of the volume of material moved on different parts of the slope in various surface runoff events, and identify spatial regularities forming rill washouts.

  20. Three-dimensional laser scanning for geometry documentation and construction management of highway tunnels during excavation.

    PubMed

    Gikas, Vassilis

    2012-01-01

    Driven by progress in sensor technology, computer software and data processing capabilities, terrestrial laser scanning has recently proved a revolutionary technique for high accuracy, 3D mapping and documentation of physical scenarios and man-made structures. Particularly, this is of great importance in the underground space and tunnel construction environment as surveying engineering operations have a great impact on both technical and economic aspects of a project. This paper discusses the use and explores the potential of laser scanning technology to accurately track excavation and construction activities of highway tunnels. It provides a detailed overview of the static laser scanning method, its principles of operation and applications for tunnel construction operations. Also, it discusses the planning, execution, data processing and analysis phases of laser scanning activities, with emphasis given on geo-referencing, mesh model generation and cross-section extraction. Specific case studies are considered based on two construction sites in Greece. Particularly, the potential of the method is examined for checking the tunnel profile, producing volume computations and validating the smoothness/thickness of shotcrete layers at an excavation stage and during the completion of excavation support and primary lining. An additional example of the use of the method in the geometric documentation of the concrete lining formwork is examined and comparisons against dimensional tolerances are examined. Experimental comparisons and analyses of the laser scanning method against conventional surveying techniques are also considered. PMID:23112655

  1. Three-Dimensional Laser Scanning for Geometry Documentation and Construction Management of Highway Tunnels during Excavation

    PubMed Central

    Gikas, Vassilis

    2012-01-01

    Driven by progress in sensor technology, computer software and data processing capabilities, terrestrial laser scanning has recently proved a revolutionary technique for high accuracy, 3D mapping and documentation of physical scenarios and man-made structures. Particularly, this is of great importance in the underground space and tunnel construction environment as surveying engineering operations have a great impact on both technical and economic aspects of a project. This paper discusses the use and explores the potential of laser scanning technology to accurately track excavation and construction activities of highway tunnels. It provides a detailed overview of the static laser scanning method, its principles of operation and applications for tunnel construction operations. Also, it discusses the planning, execution, data processing and analysis phases of laser scanning activities, with emphasis given on geo-referencing, mesh model generation and cross-section extraction. Specific case studies are considered based on two construction sites in Greece. Particularly, the potential of the method is examined for checking the tunnel profile, producing volume computations and validating the smoothness/thickness of shotcrete layers at an excavation stage and during the completion of excavation support and primary lining. An additional example of the use of the method in the geometric documentation of the concrete lining formwork is examined and comparisons against dimensional tolerances are examined. Experimental comparisons and analyses of the laser scanning method against conventional surveying techniques are also considered. PMID:23112655

  2. Building reconstruction from images and laser scanning

    NASA Astrophysics Data System (ADS)

    Brenner, Claus

    2005-03-01

    The automatic extraction of objects from laser scans and images has been a topic of research for decades. Nowadays, with new services expected, especially in the area of navigation systems, location based services, and augmented reality, the need for automated, efficient extraction systems becomes more urgent than ever. This paper reviews a number of automatic and semi-automatic reconstruction methods in more detail in order to reveal their underlying principles. It then discusses some general properties of reconstruction approaches which have evolved. This shows that, although research is still far from the goal of the initially envisioned fully automatic reconstruction systems, there is now a much better understanding of the problem and the ways it can be tackled.

  3. Automatic Railway Power Line Extraction Using Mobile Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Zhang, Shanxin; Wang, Cheng; Yang, Zhuang; Chen, Yiping; Li, Jonathan

    2016-06-01

    Research on power line extraction technology using mobile laser point clouds has important practical significance on railway power lines patrol work. In this paper, we presents a new method for automatic extracting railway power line from MLS (Mobile Laser Scanning) data. Firstly, according to the spatial structure characteristics of power-line and trajectory, the significant data is segmented piecewise. Then, use the self-adaptive space region growing method to extract power lines parallel with rails. Finally use PCA (Principal Components Analysis) combine with information entropy theory method to judge a section of the power line whether is junction or not and which type of junction it belongs to. The least squares fitting algorithm is introduced to model the power line. An evaluation of the proposed method over a complicated railway point clouds acquired by a RIEGL VMX450 MLS system shows that the proposed method is promising.

  4. Confocal laser scanning microscopy of apoptosis in organogenesis-stage mouse embryos

    EPA Science Inventory

    Confocal laser scanning microscopy combined with a vital stain has been used to study apoptosis in organogenesis-stage mouse embryos. In order to achieve optical sectioning through embryos, it was necessary to use low power objectives and to prepare the sample appropriately. Mous...

  5. Automatic change detection using mobile laser scanning

    NASA Astrophysics Data System (ADS)

    Hebel, M.; Hammer, M.; Gordon, M.; Arens, M.

    2014-10-01

    Automatic change detection in 3D environments requires the comparison of multi-temporal data. By comparing current data with past data of the same area, changes can be automatically detected and identified. Volumetric changes in the scene hint at suspicious activities like the movement of military vehicles, the application of camouflage nets, or the placement of IEDs, etc. In contrast to broad research activities in remote sensing with optical cameras, this paper addresses the topic using 3D data acquired by mobile laser scanning (MLS). We present a framework for immediate comparison of current MLS data to given 3D reference data. Our method extends the concept of occupancy grids known from robot mapping, which incorporates the sensor positions in the processing of the 3D point clouds. This allows extracting the information that is included in the data acquisition geometry. For each single range measurement, it becomes apparent that an object reflects laser pulses in the measured range distance, i.e., space is occupied at that 3D position. In addition, it is obvious that space is empty along the line of sight between sensor and the reflecting object. Everywhere else, the occupancy of space remains unknown. This approach handles occlusions and changes implicitly, such that the latter are identifiable by conflicts of empty space and occupied space. The presented concept of change detection has been successfully validated in experiments with recorded MLS data streams. Results are shown for test sites at which MLS data were acquired at different time intervals.

  6. Quality Analysis and Correction of Mobile Backpack Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Rönnholm, P.; Liang, X.; Kukko, A.; Jaakkola, A.; Hyyppä, J.

    2016-06-01

    Backpack laser scanning systems have emerged recently enabling fast data collection and flexibility to make measurements also in areas that cannot be reached with, for example, vehicle-based laser scanners. Backpack laser scanning systems have been developed both for indoor and outdoor use. We have developed a quality analysis process in which the quality of backpack laser scanning data is evaluated in the forest environment. The reference data was collected with an unmanned aerial vehicle (UAV) laser scanning system. The workflow included noise filtering, division of data into smaller patches, ground point extraction, ground data decimation, and ICP registration. As a result, we managed to observe the misalignments of backpack laser scanning data for 97 patches each including data from circa 10 seconds period of time. This evaluation revealed initial average misalignments of 0.227 m, 0.073 and -0.083 in the easting, northing and elevation directions, respectively. Furthermore, backpack data was corrected according to the ICP registration results. Our correction algorithm utilized the time-based linear transformation of backpack laser scanning point clouds. After the correction of data, the ICP registration was run again. This revealed remaining misalignments between the corrected backpack laser scanning data and the original UAV data. We found average misalignments of 0.084, 0.020 and -0.005 meters in the easting, northing and elevation directions, respectively.

  7. Laser Scanning and Simulation at Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Kickbusch, Tracey E.

    2012-01-01

    We perform simulations of ground operations leading up launch at Kennedy Space Center and Vandenberg Air Force Base in CA. We use Laser Scanning, Modeling and Simulations to make sure operations are feasible, efficient, and safe.

  8. A novel multimodal laser scanning microscope control system

    NASA Astrophysics Data System (ADS)

    Lai, Zhenhua; Gu, Zetong; Karasek, Stephen; McLean, James; Zhang, Xi; DiMarzio, Charles; Yin, Jihao; Xiong, Daxi

    2015-03-01

    Traditional laser scanning microscopes require complex control systems to synchronize and control image acquisition. The control system is especially cumbersome in the multimodal laser scanning microscope. We have developed a novel multimodal laser scanning microscope control system based on a National Instruments multifunction data acquisition device (DAQ), which serves as both a data acquisition device and a programmable signal generator. The novel control system is low-cost and easy-to-build, with all components off-the-shelf. We have applied the control system in a multimodal laser scanning microscope. The control system has not only significantly decreased the complexity of the microscope, but also increased the system flexibility. We have demonstrated that the system can be easily customized for various applications.

  9. Semiautomatic generation of three-view drawing of building using terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Liang, Yubin; Zhan, Qingming; Che, Erzhuo; Chen, Mingwen

    2014-03-01

    Terrestrial laser scanning is an effective and efficient technique for acquisition of three dimensional data of indoor and outdoor environment in a short period of time. Precision of laser scanning data are usually within millimetres, which is satisfactory for building surveying and mapping. In recent years terrestrial laser scanning has been widely used in historical building preservation and cultural heritage documentation. Three-view drawing (plan, front and section views) is standard and important presentation of building surveying and mapping. However, generation of three-view drawing of a building using terrestrial laser scanning data often entails much human intervention. In this paper we present a methodology for semiautomatic generation of three-view drawing of a building. Three-view drawing of a building is often made on virtual planes which are perpendicular to the axis directions of the building. We define the projection plane using interactively selected laser points of the building surface and project point cloud to the determined projection plane. We project point cloud data to such a virtual plane defined by interactively selected points on the surface of building. A depth image is generated based on the distance between points and the virtual plane. The generated depth image is orthographic projection of three-dimensional laser scanning scene, which preserves the structural information of a building. Then segmentation and pattern recognition methods are exploited to extract the features (geometric primitives) from the depth image. The extracted features can be further refined to generate three-view drawing of a building. The presented methodology greatly reduces volume of data in operation and experimental results show the effectiveness of the methodology.

  10. Reservoir shore development in long range terrestrial laser scanning monitoring.

    NASA Astrophysics Data System (ADS)

    Kaczmarek, Halina

    2016-04-01

    Shore zones of reservoirs are in most cases very active, getting transformed as a result of coastal processes and mass movements initiated on the slopes surrounding the reservoir. From the point of view of the users of water reservoirs shore recession strongly undesirable as it causes destruction to infrastructure and buildings located in the immediate vicinity of the reservoir. For this reason, reservoir shores require continuous geodetic monitoring. Fast and accurate geodetic measurements covering shore sections several kilometers long, often in poorly accessible areas, are available using long range terrestrial laser scanning (TLS). The possibilities of using long range terrestrial laser scanning are shown on the example of the reservoir Jeziorsko on the Warta River (Central Poland). This reservoir, created in the years 1986-1992, is a typical retention reservoir, the annual fluctuations of which reach 5 m. Depending on the water level its surface area ranges from 42.3 to 19.6 km2. The width of the reservoir is 2.5 km. The total shore length of the reservoir, developed in Quaternary till and sand-till sediments, is 44.3 km, including 30.1 km of the unreinforced shore. Out of the unreinforced shore 27% is subject to coastal erosion. The cliff heights vary from a few cm to 12.5 meters, and the current rate of the cliff recession ranges from 0 to 1.12 m/y. The study used a terrestrial long range laser scanner Riegl VZ-4000 of a range of up to 4000 m. It enabled conducting the measurements of the cliff recession from the opposite shore of the reservoir, with an angular resolution of 0.002°, which gives about 50 measurement points per 1 m2. The measurements were carried out in the years 2014-2015, twice a year, in early spring before high water level, and in late autumn at a dropping water level. This allowed the separation of the impact of coastal processes and frost weathering on the cliff recession and their quantitative determination. The size and nature of

  11. Automatic Classification of Trees from Laser Scanning Point Clouds

    NASA Astrophysics Data System (ADS)

    Sirmacek, B.; Lindenbergh, R.

    2015-08-01

    Development of laser scanning technologies has promoted tree monitoring studies to a new level, as the laser scanning point clouds enable accurate 3D measurements in a fast and environmental friendly manner. In this paper, we introduce a probability matrix computation based algorithm for automatically classifying laser scanning point clouds into 'tree' and 'non-tree' classes. Our method uses the 3D coordinates of the laser scanning points as input and generates a new point cloud which holds a label for each point indicating if it belongs to the 'tree' or 'non-tree' class. To do so, a grid surface is assigned to the lowest height level of the point cloud. The grids are filled with probability values which are calculated by checking the point density above the grid. Since the tree trunk locations appear with very high values in the probability matrix, selecting the local maxima of the grid surface help to detect the tree trunks. Further points are assigned to tree trunks if they appear in the close proximity of trunks. Since heavy mathematical computations (such as point cloud organization, detailed shape 3D detection methods, graph network generation) are not required, the proposed algorithm works very fast compared to the existing methods. The tree classification results are found reliable even on point clouds of cities containing many different objects. As the most significant weakness, false detection of light poles, traffic signs and other objects close to trees cannot be prevented. Nevertheless, the experimental results on mobile and airborne laser scanning point clouds indicate the possible usage of the algorithm as an important step for tree growth observation, tree counting and similar applications. While the laser scanning point cloud is giving opportunity to classify even very small trees, accuracy of the results is reduced in the low point density areas further away than the scanning location. These advantages and disadvantages of two laser scanning point

  12. Efficient terrestrial laser scan segmentation exploiting data structure

    NASA Astrophysics Data System (ADS)

    Mahmoudabadi, Hamid; Olsen, Michael J.; Todorovic, Sinisa

    2016-09-01

    New technologies such as lidar enable the rapid collection of massive datasets to model a 3D scene as a point cloud. However, while hardware technology continues to advance, processing 3D point clouds into informative models remains complex and time consuming. A common approach to increase processing efficiently is to segment the point cloud into smaller sections. This paper proposes a novel approach for point cloud segmentation using computer vision algorithms to analyze panoramic representations of individual laser scans. These panoramas can be quickly created using an inherent neighborhood structure that is established during the scanning process, which scans at fixed angular increments in a cylindrical or spherical coordinate system. In the proposed approach, a selected image segmentation algorithm is applied on several input layers exploiting this angular structure including laser intensity, range, normal vectors, and color information. These segments are then mapped back to the 3D point cloud so that modeling can be completed more efficiently. This approach does not depend on pre-defined mathematical models and consequently setting parameters for them. Unlike common geometrical point cloud segmentation methods, the proposed method employs the colorimetric and intensity data as another source of information. The proposed algorithm is demonstrated on several datasets encompassing variety of scenes and objects. Results show a very high perceptual (visual) level of segmentation and thereby the feasibility of the proposed algorithm. The proposed method is also more efficient compared to Random Sample Consensus (RANSAC), which is a common approach for point cloud segmentation.

  13. Managing multiple image stacks from confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Zerbe, Joerg; Goetze, Christian H.; Zuschratter, Werner

    1999-05-01

    A major goal in neuroanatomy is to obtain precise information about the functional organization of neuronal assemblies and their interconnections. Therefore, the analysis of histological sections frequently requires high resolution images in combination with an overview about the structure. To overcome this conflict we have previously introduced a software for the automatic acquisition of multiple image stacks (3D-MISA) in confocal laser scanning microscopy. Here, we describe a Windows NT based software for fast and easy navigation through the multiple images stacks (MIS-browser), the visualization of individual channels and layers and the selection of user defined subregions. In addition, the MIS browser provides useful tools for the visualization and evaluation of the datavolume, as for instance brightness and contrast corrections of individual layers and channels. Moreover, it includes a maximum intensity projection, panning and zoom in/out functions within selected channels or focal planes (x/y) and tracking along the z-axis. The import module accepts any tiff-format and reconstructs the original image arrangement after the user has defined the sequence of images in x/y and z and the number of channels. The implemented export module allows storage of user defined subregions (new single image stacks) for further 3D-reconstruction and evaluation.

  14. Confocal laser scanning microscopy in study of bone calcification

    NASA Astrophysics Data System (ADS)

    Nishikawa, Tetsunari; Kokubu, Mayu; Kato, Hirohito; Imai, Koichi; Tanaka, Akio

    2012-12-01

    Bone regeneration in mandible and maxillae after extraction of teeth or tumor resection and the use of rough surface implants in bone induction must be investigated to elucidate the mechanism of calcification. The calcified tissues are subjected to chemical decalcification or physical grinding to observe their microscopic features with light microscopy and transmission electron microscopy where the microscopic tissue morphology is significantly altered. We investigated the usefulness of confocal laser scanning microscopy (CLSM) for this purpose. After staggering the time of administration of calcein and alizarin red to experimental rats and dogs, rat alveolar bone and dog femur grafted with coral as scaffold or dental implants were observed with CLSM. In rat alveolar bone, the calcification of newly-formed bone and net-like canaliculi was observed at the mesial bone from the roots progressed at the rate of 15 μm/day. In dog femur grafted with coral, newly-formed bones along the space of coral were observed in an orderly manner. In dog femur with dental implants, after 8 weeks, newly-formed bone proceeded along the rough surface of the implants. CLSM produced high-magnification images of newly-formed bone and thin sections were not needed.

  15. Architectural stability analysis of the rotary-laser scanning technique

    NASA Astrophysics Data System (ADS)

    Xue, Bin; Yang, Xiaoxia; Zhu, Jigui

    2016-03-01

    The rotary-laser scanning technique is an important method in scale measurements due to its high accuracy and large measurement range. This paper first introduces a newly designed measurement station which is able to provide two-dimensional measurement information including the azimuth and elevation by using the rotary-laser scanning technique, then presents the architectural stability analysis of this technique by detailed theoretical derivations. Based on the designed station, a validation using both experiment and simulation is presented in order to verify the analytic conclusion. The results show that the architectural stability of the rotary-laser scanning technique is only affected by the two scanning angles' difference. And the difference which brings the best architectural stability can be calculated by using pre-calibrated parameters of the two laser planes. This research gives us an insight into the rotary-laser scanning technique. Moreover, the measurement accuracy of the rotary-laser scanning technique can be further improved based on the results of the study.

  16. Microscopic tomography by laser scanning microscopy and its three-dimensional reconstruction.

    PubMed

    Takamatsu, T; Fujita, S

    1988-03-01

    We have developed a new confocal laser scanning microscope equipped with two galvanometer mirrors which swing the laser beam. With this set up we can observe large and fragile specimens. Using a focused laser beam as light source to minimize 'flare' and a pinhole in front of a photodetector to eliminate out-of-focus data, we could obtain a depth-discriminated fluorescence image. The scanning apparatus of our system can eliminate mechanical vibration and sweep widely, to obtain images at a low magnification. A thinly sectioned image with high resolution and high contrast could be obtained optically from an in situ thick specimen. We have called this technique 'microscopic tomography'. Combining the laser scanning microscope with the colour image analyser generated semi-automatically a three-dimensional picture of the biological material with information on its interior. PMID:3398041

  17. Benchmarking Mobile Laser Scanning Systems Using a Permanent Test Field

    NASA Astrophysics Data System (ADS)

    Kaartinen, H.; Kukko, A.; Hyyppä, J.; Jaakkola, A.

    2012-07-01

    The objective of the study was to benchmark the geometric accuracy of mobile laser scanning (MLS) systems using a permanent test field under good coverage of GNSS. Mobile laser scanning, also called mobile terrestrial laser scanning, is currently a rapidly developing area in laser scanning where laser scanners, GNSS and IMU are mounted onboard a moving vehicle. MLS can be considered to fill the gap between airborne and terrestrial laser scanning. Data provided by MLS systems can be characterized with the following technical parameters: a) point density in the range of 100-1000 points per m2 at 10 m distance, b) distance measurement accuracy of 2-5 cm, and c) operational scanning range from 1 to 100 m. Several commercial, including e.g. Riegl, Optech and others, and some research mobile laser scanning systems surveyed the test field using predefined driving speed and directions. The acquired georeferenced point clouds were delivered for analyzing. The geometric accuracy of the point clouds was determined using the reference targets that could be identified and measured from the point cloud. Results show that in good GNSS conditions most systems can reach an accuracy of 2 cm both in plane and elevation. The accuracy of a low cost system, the price of which is less than tenth of the other systems, seems to be within a few centimetres at least in ground elevation determination. Inaccuracies in the relative orientation of the instruments lead to systematic errors and when several scanners are used, in multiple reproductions of the objects. Mobile laser scanning systems can collect high density point cloud data with high accuracy. A permanent test field suits well for verifying and comparing the performance of different mobile laser scanning systems. The accuracy of the relative orientation between the mapping instruments needs more attention. For example, if the object is seen double in the point cloud due to imperfect boresight calibration between two scanners, this

  18. Application of in vivo laser scanning microscope in dermatology

    NASA Astrophysics Data System (ADS)

    Lademann, Juergen; Richter, H.; Otberg, N.; Lawrenz, F.; Blume-Peytavi, U.; Sterry, W.

    2003-10-01

    The state of the art of in-vivo and in-vitro penetration measurements of topically applied substances is described. Only optical techniques represent online measuring methods based on the absorption or scattering properties of the topically applied substances. Laser scanning microscopy (LSM) has become a promising method for investigations in dermatology and skin physiology, after it was possible to analyze the skin surface on any body side in-vivo. In the present paper the application of a dermatological laser scanning microscope for penetration and distribution measurements of topically applied substances is described. The intercellular and follicular penetration pathways were studied.

  19. Material characterization with a simple laser scanning microscope.

    PubMed

    Krug, R; Würfel, P; Ruppel, W

    1993-11-10

    The design of a computer-controlled laser scanning microscope is described. It is capable of inspecting a 1 mm × 1 mm area in less than 1 s with an optical resolution of 2 µm. Three applications of the laser scanning microscope are presented: the observation of the ferroelectric-domain structure of sodium nitrite layers, the observation of the spatial distribution of the photocurrent in polycrystalline solar cells, and the observation of the lateral distribution of thermoelectric currents in a thermal IR detector for the determination of the thermal properties of its absorber foil.

    PACS: 0760P, 7240, 7780D.

    PMID:20856484

  20. Laser scanning cytometry as a tool for biomarker validation

    NASA Astrophysics Data System (ADS)

    Mittag, Anja; Füldner, Christiane; Lehmann, Jörg; Tarnok, Attila

    2013-03-01

    Biomarkers are essential for diagnosis, prognosis, and therapy. As diverse is the range of diseases the broad is the range of biomarkers and the material used for analysis. Whereas body fluids can be relatively easily obtained and analyzed, the investigation of tissue is in most cases more complicated. The same applies for the screening and the evaluation of new biomarkers and the estimation of the binding of biomarkers found in animal models which need to be transferred into applications in humans. The latter in particular is difficult if it recognizes proteins or cells in tissue. A better way to find suitable cellular biomarkers for immunoscintigraphy or PET analyses may be therefore the in situ analysis of the cells in the respective tissue. In this study we present a method for biomarker validation using Laser Scanning Cytometry which allows the emulation of future in vivo analysis. The biomarker validation is exemplarily shown for rheumatoid arthritis (RA) on synovial membrane. Cryosections were scanned and analyzed by phantom contouring. Adequate statistical methods allowed the identification of suitable markers and combinations. The fluorescence analysis of the phantoms allowed the discrimination between synovial membrane of RA patients and non-RA control sections by using median fluorescence intensity and the "affected area". As intensity and area are relevant parameters of in vivo imaging (e.g. PET scan) too, the presented method allows emulation of a probable outcome of in vivo imaging, i.e. the binding of the target protein and hence, the validation of the potential of the respective biomarker.

  1. Photobleaching property of confocal laser scanning microscopy with masked illumination

    NASA Astrophysics Data System (ADS)

    Kim, DongUk; Moon, Sucbei; Song, Hoseong; Yang, Wenzhong; Kim, Dug Y.

    2010-02-01

    Confocal laser scanning microscopy (CLSM) has become the tool of choice for high-contrast fluorescence imaging in the study of the three-dimensional and dynamic properties of biological system. However, the high cost and complexity of commercial CLSMs urges many researchers to individually develop low cost and flexible confocal microscopy systems. The high speed scanner is an influential factor in terms of cost and system complexity. Resonant galvo scanners at several kHz have been commonly used in custom-built CLSMs. However, during the repeated illumination for live cell imaging or 3D image formation, photobleaching and image distortion occurred at the edges of the scan field may be more serious than the center due to an inherent property (e.g. sinusoidal angular velocity) of the scan mirror. Usually, no data is acquired at the edges due to large image distortion but the excitation beam is still illuminated. Here, we present the photobleaching property of CLSM with masked illumination, a simple and low cost method, to exclude the unintended excitation illumination at the edges. The mask with a square hole in its center is disposed at the image plane between the scan lens and the tube lens in order to decrease photobleaching and image distortion at the edges. The excluded illumination section is used as the black level of the detected signals for a signal quantizing step. Finally, we demonstrated the reduced photobleaching at the edges on a single layer of fluorescent beads and real-time image acquisition without a standard composite video signal by using a frame grabber.

  2. FOOD SURFACE TEXTURE MEASUREMENT USING REFLECTIVE CONFOCAL LASER SCANNING MICROSCOPY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Confocal laser scanning microscopy (CLSM) was used in the reflection mode to characterize the surface texture (roughness) of sliced food surfaces. Sandpapers of grit size between 150 and 600 were used as the height reference to standardize the CLSM hardware settings. Sandpaper particle sizes were v...

  3. Planar Projection of Mobile Laser Scanning Data in Tunnels

    NASA Astrophysics Data System (ADS)

    Gonçalves, J. A.; Mendes, R.; Araújo, E.; Oliveira, A.; Boavida, J.

    2012-07-01

    Laser scanning is now a common technology in the surveying and monitoring of large engineering infrastructures, such as tunnels, both in motorways and railways. Extended possibilities exist now with the mobile terrestrial laser scanning systems, which produce very large data sets that need efficient processing techniques in order to facilitate their exploitation and usability. This paper deals with the implementation of a methodology for processing and presenting 3D point clouds acquired by laser scanning in tunnels, making use of the approximately cylindrical shape of tunnels. There is a need for a 2D presentation of the 3D point clouds, in order to facilitate the inspection of important features as well as to easily obtain their spatial location. An algorithm was developed to treat automatically point clouds obtained in tunnels in order to produce rectified images that can be analysed. Tests were carried with data acquired with static and mobile Riegl laser scanning systems, by Artescan company, in highway tunnels in Portugal and Spain, with very satisfactory results. The final planar image is an alternative way of data presentation where image analysis tools can be used to analyze the laser intensity in order to detect problems in the tunnel structure.

  4. Possibilities of holographic techniques in laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Zakharov, Yu.; Muravyeva, M.; Dudenkova, V.; Mukhina, I.; Meglinski, I.

    2015-07-01

    Holographic scanning microscopy - novel technique both in laser scanning microscopy and digital holographic microscopy allow multimodal approach to cell and tissue investigation in biomedical applications promising new advantages (quantitative phase imaging, superresolution, computerized tomography), but regular reconstruction leads to incorrectness. Analysis of light propagation through the schematics allows to offer reconstruction procedures depending on recording conditions.

  5. CONFOCAL LASER SCANNING MICROSCOPY OF RAT FOLLICLE DEVELOPMENT

    EPA Science Inventory

    This study used confocal laser scanning microscopy (CLSM) to study follicular development in millimeter pieces of rat ovary. To use this technology, it is essential to stain the tissue before laser excitation with the confocal microscope. Various fluorescent stains (Yo-Pro, Bo-Pr...

  6. Laser scanned image sensors using photoconductors with deep traps

    NASA Technical Reports Server (NTRS)

    Maserjian, J.

    1975-01-01

    Photoconductor records image when holes and electrons are trapped inside it due to incident photons. Image can be read out by exposing photoconductor to scanning laser beam. Photons from scanning laser empty traps, generating photocurrent. Image information is obtained by detecting this photocurrent synchronously with laser scan.

  7. Laser-scanning techniques for rapid ballistics identification

    NASA Technical Reports Server (NTRS)

    Woodburgy, R. C.; Nakich, R. B.

    1974-01-01

    Two different laser-scanning methods may be utilized. In each case scanned cylindrical bullet surface is displayed ""unwrapped'' on oscilloscope screen. Bullets are compared by photographing each display and superimposing negatives of two images. With some modifications bullets can be scanned and compared by superimposing images on screen of dual-beam oscilloscope.

  8. Intersecting kink bands quantified by laser scanning and differential geometry

    NASA Astrophysics Data System (ADS)

    Dunham, R. E.; Crider, J. G.

    2010-12-01

    Microtopography derived from laser scanning is expressed by DEMs that can be analyzed using differential geometry. We apply this technique to rock hand samples containing intersecting kink bands in order to quantitatively describe the shape of a folded surface and understand the localization of strain in deformed rocks. This study is the first to apply laser scanning and geometric curvature analysis to intersecting kink bands in order to better describe the variation of kink band geometries and intersections in plan view and to evaluate relationships between different kink band parameters. A complex set of monoclinal contractional kink bands is well exposed in outcrops of the Darrington Phyllite on Samish Island, northwestern Washington, which provide a three-dimensional view of kink band geometries. Kink bands in cross section have straight, parallel boundaries that deform a well-defined foliation; in plan view, however, kink band hinges curve and anastomose across the foliation surface, and adjacent bands commonly intersect. Three types of intersections are common: crossing (X), bifurcating (Y), and obliquely truncating (λ); many kink bands also taper out along strike. Geometric curvature analyses were performed on millimeter-resolution DEMs of hand samples containing intersecting kink bands. Maps of different curvature parameters (e.g. mean curvature, geologic curvature) clearly outline kink bands in the samples and illuminate the behavior of kink band hinges in each type of intersection. In X-type intersections, curvature increases where two hinges of similar kink sense cross (i.e. anticlinal/anticlinal hinges), increasing strain; where two hinges of opposing sense cross (anticlinal/synclinal), curvature decreases and the surface is effectively unfolded. In Y-type intersections, a single parent band widens and splits into two equally narrow daughter bands, and new inner hinges are nucleated below the bifurcation point. The two daughter bands accommodate

  9. Airborne laser scanning for high-resolution mapping of Antarctica

    NASA Astrophysics Data System (ADS)

    Csatho, Bea; Schenk, Toni; Krabill, William; Wilson, Terry; Lyons, William; McKenzie, Garry; Hallam, Cheryl; Manizade, Serdar; Paulsen, Timothy

    In order to evaluate the potential of airborne laser scanning for topographic mapping in Antarctica and to establish calibration/validation sites for NASA's Ice, Cloud and land Elevation Satellite (ICESat) altimeter mission, NASA, the U.S. National Science Foundation (NSF), and the U.S. Geological Survey (USGS) joined forces to collect high-resolution airborne laser scanning data.In a two-week campaign during the 2001-2002 austral summer, NASA's Airborne Topographic Mapper (ATM) system was used to collect data over several sites in the McMurdo Sound area of Antarctica (Figure 1a). From the recorded signals, NASA computed laser points and The Ohio State University (OSU) completed the elaborate computation/verification of high-resolution Digital Elevation Models (DEMs) in 2003. This article reports about the DEM generation and some exemplary results from scientists using the geomorphologic information from the DEMs during the 2003-2004 field season.

  10. Optimal lens design and use in laser-scanning microscopy

    PubMed Central

    Negrean, Adrian; Mansvelder, Huibert D.

    2014-01-01

    In laser-scanning microscopy often an off-the-shelf achromatic doublet is used as a scan lens which can reduce the available diffraction-limited field-of-view (FOV) by a factor of 3 and introduce chromatic aberrations that are scan angle dependent. Here we present several simple lens designs of superior quality that fully make use of high-NA low-magnification objectives, offering diffraction-limited imaging over a large FOV and wavelength range. We constructed a two-photon laser-scanning microscope with optimized custom lenses which had a near diffraction limit point-spread-function (PSF) with less than 3.6% variation over a 400 µm FOV and less than 0.5 µm lateral color between 750 and 1050 nm. PMID:24877017

  11. Software for visualization, analysis, and manipulation of laser scan images

    NASA Astrophysics Data System (ADS)

    Burnsides, Dennis B.

    1997-03-01

    The recent introduction of laser surface scanning to scientific applications presents a challenge to computer scientists and engineers. Full utilization of this two- dimensional (2-D) and three-dimensional (3-D) data requires advances in techniques and methods for data processing and visualization. This paper explores the development of software to support the visualization, analysis and manipulation of laser scan images. Specific examples presented are from on-going efforts at the Air Force Computerized Anthropometric Research and Design (CARD) Laboratory.

  12. Modelling Braided River Morphodynamics With Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Brasington, J.; Wheaton, J. M.; Vericat, D.; Hodge, R.

    2007-12-01

    Advances in topographic survey and terrain modelling have enabled a revolution in the study in the fluvial morphodynamics in the last decade. Prior to the advent of electronic tacheometry in the 1990s, the analysis of channel dynamics was typically inferred from a combination of cross-section surveys and planform mapping. Distributed surveys acquired with GPS or EDMs enabled this analysis to be dimensionally extended and the pattern and magnitude morphodynamics elucidated in 3D; in particular through DTM differencing. Continuing developments in survey technology are now posed to reset this field once again. Now no longer confined to the laboratory, ruggedized laser scanners are capable of acquiring between 4-50,000 observations per second, at ranges exceeding 100 m. This latest development creates the potential for typical reach-scale (1-10 km) topographic datasets to rise in size by 7 orders of magnitude (hundreds to billions of points) in the coming years. Terrestrial Laser Scanning (TLS) offers a wealth of opportunities to better monitor fluvial systems; improving models of cut-and-fill, roughness and enhancing the prospect for ever more detailed parameterizations for fluid models. While this technology enables the creation of 'virtual facsimiles' of landscapes, the demands of storing, processing and modelling geomorphological products from such data requires a wholesale reappraisal of our data management and modelling methods. Here we outline a field-to-product methodology for TLS of fluvial systems using data from two annual surveys of a 1 km reach of the River Feshie, Scotland. These surveys delivered 3D point cloud datasets, incorporating over 200 million xyz observations, with median spatial densities of over 1000 pts/m2. The surveys were fixed to a GPS-based control network, including over 200 coincident tie- points to register multiple setups to a global coordinate system (RMS errors 0.002-0.011 m). Modelling reach-scale geometries from such dense point

  13. Clinical applications of in vivo fluorescence confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Oh, Chilhwan; Park, Sangyong; Kim, Junhyung; Ha, Seunghan; Park, Gyuman; Lee, Gunwoo; Lee, Onseok; Chun, Byungseon; Gweon, Daegab

    2008-02-01

    Living skin for basic and clinical research can be evaluated by Confocal Laser Scanning Microscope (CLSM) non-invasively. CLSM imaging system can achieve skin image its native state either "in vivo" or "fresh biopsy (ex vivo)" without fixation, sectioning and staining that is necessary for routine histology. This study examines the potential fluorescent CLSM with a various exogenous fluorescent contrast agent, to provide with more resolution images in skin. In addition, in vivo fluorescent CLSM researchers will be extended a range of potential clinical application. The prototype of our CLSM system has been developed by Prof. Gweon's group. The operating parameters are composed of some units, such as illuminated wavelength 488 nm, argon illumination power up to 20mW on the skin, objective lens, 0.9NA oil immersion, axial resolution 1.0μm, field of view 200μm x 100μm (lateral resolution , 0.3μm). In human volunteer, fluorescein sodium was administrated topically and intradermally. Animal studies were done in GFP transgenic mouse, IRC mouse and pig skin. For imaging of animal skin, fluorescein sodium, acridine orange, and curcumine were used for fluorescein contrast agent. We also used the GFP transgenic mouse for fluorescein CLSM imaging. In intact skin, absorption of fluorescein sodium by individual corneocyte and hair. Intradermal administrated the fluorescein sodium, distinct outline of keratinocyte cell border could be seen. Curcumin is a yellow food dye that has similar fluorescent properties to fluorescein sodium. Acridin Orange can be highlight nuclei in viable keratinocyte. In vivo CLSM of transgenic GFP mouse enable on in vivo, high resolution view of GFP expressing skin tissue. GFP signals are brightest in corneocyte, kertinocyte, hair and eccrine gland. In intact skin, absorption of fluorescein sodium by individual corneocyte and hair. Intradermal administrated the fluorescein sodium, distinct outline of keratinocyte cell border could be seen. In

  14. Transmissive liquid-crystal device correcting primary coma aberration and astigmatism in laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Tanabe, Ayano; Hibi, Terumasa; Ipponjima, Sari; Matsumoto, Kenji; Yokoyama, Masafumi; Kurihara, Makoto; Hashimoto, Nobuyuki; Nemoto, Tomomi

    2016-03-01

    Laser scanning microscopy allows 3D cross-sectional imaging inside biospecimens. However, certain aberrations produced can degrade the quality of the resulting images. We previously reported a transmissive liquid-crystal device that could compensate for the predominant spherical aberrations during the observations, particularly in deep regions of the samples. The device, inserted between the objective lens and the microscope revolver, improved the image quality of fixed-mouse-brain slices that were observed using two-photon excitation laser scanning microscopy, which was originally degraded by spherical aberration. In this study, we developed a transmissive device that corrects primary coma aberration and astigmatism, motivated by the fact that these asymmetric aberrations can also often considerably deteriorate image quality, even near the sample surface. The device's performance was evaluated by observing fluorescent beads using single-photon excitation laser scanning microscopy. The fluorescence intensity in the image of the bead under a cover slip tilted in the y-direction was increased by 1.5 times after correction by the device. Furthermore, the y- and z-widths of the imaged bead were reduced to 66% and 65%, respectively. On the other hand, for the imaged bead sucked into a glass capillary in the longitudinal x-direction, correction with the device increased the fluorescence intensity by 2.2 times compared to that of the aberrated image. In addition, the x-, y-, and z-widths of the bead image were reduced to 75%, 53%, and 40%, respectively. Our device successfully corrected several asymmetric aberrations to improve the fluorescent signal and spatial resolution, and might be useful for observing various biospecimens.

  15. Visualization and quantification of dentin structure using confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Kimura, Yuichi; Wilder-Smith, Petra B.; Krasieva, Tatiana B.; Arrastia-Jitosho, Anna-Marie A.; Liaw, Lih-Huei L.; Matsumoto, Koukichi

    1997-07-01

    Dentin was visualized using a new fluorescence technique and confocal laser scanning microscopy. Thirty extracted human teeth showing no clinical signs of caries were investigated. All teeth were horizontally sectioned to approximately 200 micrometers thickness and sections were subjected to different pretreatment conditions as follows: vacuum only, ultrasonication only, sodium hypochlorite only, sodium hypochlorite and vacuum, sodium hypochlorite and ultrasonication, and a combination of sodium hypochlorite, vacuum, and ultrasonication. Some samples were left untreated to serve as control. Following pretreatment, rhodamine 123 fluorescent dye was used for staining at concentrations ranging from 10-3 to 10-7 M for 1 to 24 h at pH 6.0, 6.5, or 7.4. Optical staining occurred at pH 7.4 and concentrations >= 10-5 M over 3 h or longer. Surface images obtained using confocal laser scanning microscopy were similar to those observed by scanning electron microscopy without the need for sample- altering conventional scanning electron microscope preparation techniques. Subsurface imaging to a depth of approximately 60 micrometers was achieved using confocal laser microscope techniques. This fluorescence technique offers a useful new alternative for visualization and quantification of dentin.

  16. Laser-scanning optical-resolution photoacoustic microscopy.

    PubMed

    Xie, Zhixing; Jiao, Shuliang; Zhang, Hao F; Puliafito, Carmen A

    2009-06-15

    We have developed a laser-scanning optical-resolution photoacoustic microscopy method that can potentially fuse with existing optical microscopic imaging modalities. To acquire an image, the ultrasonic transducer is kept stationary during data acquisition, and only the laser light is raster scanned by an x-y galvanometer scanner. A lateral resolution of 7.8 microm and a circular field of view with a diameter of 6 mm were achieved in an optically clear medium. Using a laser system working at a pulse repetition rate of 1,024 Hz, the data acquisition time for an image consisting of 256 x 256 pixels was less than 2 min. PMID:19529698

  17. Monitoring stream bluff erosion using repeat terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Neitzel, G.; Gran, K. B.

    2012-12-01

    Terrestrial laser scanning (TLS) technology provides high-resolution topographic data that can be used to detect geomorphic change in fluvial environments. In this study, we utilize successive terrestrial laser scans to investigate the relationship between peak flow rates and stream bluff erosion in the Amity Creek watershed in Duluth, Minnesota. We also combine TLS scan results with bluff inventories from airborne lidar to estimate the volume of sediment erosion from bluffs in the watershed, which is an important source of fine sediment contributing to the creek's turbidity impairment. We selected nine study bluffs to conduct terrestrial laser scans on after all significant flood events over a two-year time period. The study employs a Faro Focus 3D phase-shift laser to collect data. Post-processing of the TLS-point cloud data sets involves: (1) removal of vegetation and objects other than the erosional surface of interest; (2) decimation of the point cloud in PC Tools and extraction of zmin values to produce a data set manageable in GIS; (3) creation of a bare earth digital elevation model (DEM) for each set of scans using ArcMap; and (4) utilization of Geomorphic Change Detection (GCD) software to generate DEMs of Difference (DODs) from subsequent terrestrial laser scans. Preliminary results from three flooding events indicate significant erosional activity at all field sites. Slumps were observed at two bluffs following spring melt and freeze/thaw cycling. Two major precipitation events in late spring and early summer provided a unique opportunity to observe the impact of extreme high flow events on bluff erosion throughout the watershed using TLS technology. 4.75 inches of intermittent rain over a six-day period in late May 2012 (May 23-28) resulted in slumping at many bluffs and one major failure. The ≥100-year flood that occurred on June 19-20 (7.25 inches), 2012 was powerful enough to induce considerable channel change. Slumps occurred at six study sites

  18. Laser scanning system for inspecting large underwater hydroelectric structures

    NASA Astrophysics Data System (ADS)

    Mirallès, François; Beaudry, Julien; Blain, Michel; de Santis, Romano M.; Houde, Régis; Hurteau, Richard; Robert, André; Sarraillon, Serge; Soucy, Nathalie

    2010-04-01

    A novel robotic laser scanning system for the inspection of large underwater hydroelectric structures is proposed. This system has been developed at the Hydro Quebec Research Institute and consists of a laser camera mounted on a 2-D Cartesian manipulator. Mechanical, electronic, and software design aspects; overall operational modalities; and proof of concept results are presented. We evaluated the performances of the system in the course of laboratory experiments and inspection trials carried out under normal operating conditions at the site of three of Hydro Quebec's hydroelectric dams.

  19. Registration Procedures for Terrestrial Laser Scanning in Geomorphologic Studies

    NASA Astrophysics Data System (ADS)

    Collins, B. D.; Kayen, R.; Minasian, D.

    2006-12-01

    Terrestrial based laser scanning, from either vehicle or tripod mounts allows the collection of geomorphologic data at previously unprecedented detail and volume. However, despite the ease of collecting this data in many settings, post-processing datasets collected without laser-visible reflectors within individual scans can lead to difficulties in both registration and georeferencing procedures. We have been actively involved in gathering data sets from a number of different environments and have been developing various techniques to post-process the data using surface registration methods. These methods use the point cloud or model surface to find a best-fit of the three-dimensional terrain. Recently, we have collected laser scan data of levee breaches in New Orleans following Hurricane Katrina, a glacial cirque basin in the Canadian Rockies, a deep-seated landslide mass in Ventura County, California, rapidly evolving coastal bluffs in Central California, and sand bars and archeological sites in Grand Canyon National Park, Arizona. In each of these projects, setting up accurately surveyed reflectors was impractical due to the locations dynamic and fairly inaccessible setting. Robust surface registration procedures were therefore needed to provide accurate terrain models. We have used laser scanning results from these projects to assess the efficiency of the various post- processing methodologies for obtaining final registered and georeferenced point clouds and surface models. We compared registration results obtained both with and without accurate GPS coordinates for the laser scanner origin (Ventura and coastal landslides), use of a supporting total station unit (Grand Canyon), and collection of DGPS data on targets imaged in the LIDAR data after the scanning process (Katrina Levees). In many of these settings, the model fit improved by four times, from a root mean square error of 20 cm to 5cm when accurately surveyed coordinates were utilized for the laser scan

  20. Segment based shape matching in terrestrial laser scanning point clouds

    NASA Astrophysics Data System (ADS)

    Bremer, Magnus; Rutzinger, Martin; Wichmann, Volker

    2013-04-01

    Change detection of dynamic surface elements is an important application in geomorphological analysis. In order to be able to investigate such changes, the high spatial resolution and accuracy of the laser scanning technology is exploited. Dealing with laser scanning data, most change detection approaches are aiming at the assessment of volumetric changes due to erosion and deposition by geomorphologic processes. In these cases the areas of erosion and deposition are spatially separated and can be investigated in a cut-and-fill analysis. Where slow changes are controlled by interior deformation of material mixtures due to gravity, surface changes are mostly due to slight movements of objects and not to absolute material losses and gains. In complex terrain an object-based approach for the reconstruction of 3D change vectors is required. Depending on the level of scale, terrain can be subdivided into a large number of small planar patches. Using 3D point cloud data from terrestrial laser scanning, this can be done by a planar segmentation procedure grouping laser points of flat surfaces. Rotating each point cloud segment into its best fit plane, its 2D footprint shows specific local surface characteristics. Thus, each surface patch has a unique fingerprint that can be described by a variety of segment features. In an experimental framework we test the capability of shape based matching for the derivation of change vectors on dynamic surfaces. To consider different data characteristics such as varying point densities and scan perspectives, terrestrial laser scans of a rock glacier are acquired from three positions with an Optech ILRIS3D terrestrial laser scanner. Additionally, the point density is manipulated in order to simulate three different levels of point density. For the matching of surface patches, we test various non-metric shape features such as roundness, concavity and elongation. Besides, we use metric shape features such as patch area, perimeter and the

  1. Visualisation of urban airborne laser scanning data with occlusion images

    NASA Astrophysics Data System (ADS)

    Hinks, Tommy; Carr, Hamish; Gharibi, Hamid; Laefer, Debra F.

    2015-06-01

    Airborne Laser Scanning (ALS) was introduced to provide rapid, high resolution scans of landforms for computational processing. More recently, ALS has been adapted for scanning urban areas. The greater complexity of urban scenes necessitates the development of novel methods to exploit urban ALS to best advantage. This paper presents occlusion images: a novel technique that exploits the geometric complexity of the urban environment to improve visualisation of small details for better feature recognition. The algorithm is based on an inversion of traditional occlusion techniques.

  2. Ta Keo Temple Reconstruction Based on Terrestrial Laser Scanning Technology

    NASA Astrophysics Data System (ADS)

    Xi, X.; Wang, C.; Wan, Y. P.; Khuon, K. N.

    2015-08-01

    Ta Keo temple is one of the very famous temple complex of Angkor Wat in northwestern Cambodia. It has been suffering massive collapse and other serious damages in recent years. Nowadays, Terrestrial Laser Scanning(TLS) technology is considered as a wellestablished resource for heritage documentation and protection (Lerma et al, 2008; Reshetyuk, 2009). This paper used TLS to reconstruct Ta Keo Temple. Firstly, we acquired 71 scanning stations of points cloud data with high density and high accuracy, and over one thousand images with high spatial resolution about the temple. Secondly, the raw points cloud data were denoised, reduced and managed efficiently, and registrated using an adjusted ICP algorithm. Thirdly, a triangulation method was used to model most objects. At last, we mapped the texture data into the digital model and a 3-D model of Ta Keo with high accuracy was achieved. The authors focus on large object reconstruction by TLS technology, and pay much attention to the scanning design, multi-station data and the whole project's data registration, and texture mapping and so on. The research result will be useful for Ta Keo restoration, reconstruction and protection. Also, it is a good reference source for large complex buildings reconstruction when using terrestrial laser scanning technology.

  3. Laser-scanning photostimulation of optogenetically targeted forebrain circuits.

    PubMed

    Lee, Charles C; Lam, Ying-Wan; Imaizumi, Kazuo; Sherman, S Murray

    2013-01-01

    The sensory forebrain is composed of intricately connected cell types, of which functional properties have yet to be fully elucidated. Understanding the interactions of these forebrain circuits has been aided recently by the development of optogenetic methods for light-mediated modulation of neuronal activity. Here, we describe a protocol for examining the functional organization of forebrain circuits in vitro using laser-scanning photostimulation of channelrhodopsin, expressed optogenetically via viral-mediated transfection. This approach also exploits the utility of cre-lox recombination in transgenic mice to target expression in specific neuronal cell types. Following transfection, neurons are physiologically recorded in slice preparations using whole-cell patch clamp to measure their evoked responses to laser-scanning photostimulation of channelrhodopsin expressing fibers. This approach enables an assessment of functional topography and synaptic properties. Morphological correlates can be obtained by imaging the neuroanatomical expression of channelrhodopsin expressing fibers using confocal microscopy of the live slice or post-fixed tissue. These methods enable functional investigations of forebrain circuits that expand upon more conventional approaches. PMID:24430760

  4. Wedge-filtering of geomorphologic terrestrial laser scan data.

    PubMed

    Panholzer, Helmut; Prokop, Alexander

    2013-01-01

    Terrestrial laser scanning is of increasing importance for surveying and hazard assessments. Digital terrain models are generated using the resultant data to analyze surface processes. In order to determine the terrain surface as precisely as possible, it is often necessary to filter out points that do not represent the terrain surface. Examples are vegetation, vehicles, and animals. Filtering in mountainous terrain is more difficult than in other topography types. Here, existing automatic filtering solutions are not acceptable, because they are usually designed for airborne scan data. The present article describes a method specifically suitable for filtering terrestrial laser scanning data. This method is based on the direct line of sight between the scanner and the measured point and the assumption that no other surface point can be located in the area above this connection line. This assumption is only true for terrestrial laser data, but not for airborne data. We present a comparison of the wedge filtering to a modified inverse distance filtering method (IDWMO) filtered point cloud data. Both methods use manually filtered surfaces as reference. The comparison shows that the mean error and root-mean-square-error (RSME) between the results and the manually filtered surface of the two methods are similar. A significantly higher number of points of the terrain surface could be preserved, however, using the wedge-filtering approach. Therefore, we suggest that wedge-filtering should be integrated as a further parameter into already existing filtering processes, but is not suited as a standalone solution so far. PMID:23429548

  5. Imaging of calcium wave propagation in guinea-pig ventricular cell pairs by confocal laser scanning microscopy.

    PubMed

    Takamatsu, T; Minamikawa, T; Kawachi, H; Fujita, S

    1991-08-01

    We describe here the use of a confocal laser scanning microscope for imaging fast dynamic changes of the intracellular calcium ion concentration ([Ca2+]i) in isolated ventricular cell pairs. The scanning apparatus of our system, paired galvanometer mirrors, can perform narrow band scanning of an area of interest at a high temporal resolution of less than 70 msec per image. The actual [Ca2+]i is obtained directly through the fluorescence intensity of injected fluo-3, which responds to changes of [Ca2+]i in optically sectioned unit volumes of the cell. Images of the calcium wave obtained during propagation between paired cells revealed that the wavefront is constant in shape and propagates at constant velocity without any delay at the cell-to-cell junction. The confocal laser scanning microscope with depth-discriminating ability is a valuable tool for taking pictures of the sequence of biological events in living cells. PMID:1782671

  6. Visualization of microcrack anisotropy in granite affected by afault zone, using confocal laser scanning microscope

    SciTech Connect

    Onishi, Celia T.; Shimizu, Ichiko

    2004-01-02

    Brittle deformation in granite can generate a fracture system with different patterns. Detailed fracture analyses at both macroscopic and microscopic scales, together with physical property data from a drill-core, are used to classify the effects of reverse fault deformation in four domains: (1) undeformed granite, (2) fractured granite with cataclastic seams, (3) fractured granite from the damage zone, and (4) foliated cataclasite from the core of the fault. Intact samples from two orthogonal directions, horizontal (H) and vertical (V), from the four domains indicate a developing fracture anisotropy toward the fault, which is highly developed in the damage zone. As a specific illustration of this phenomenon, resin impregnation, using a confocal laser scanning microscope (CLSM) technique is applied to visualize the fracture anisotropy developed in the Toki Granite, Japan. As a result, microcrack networks have been observed to develop in H sections and elongate open cracks in V sections, suggesting that flow pathways can be determined by deformation.

  7. Confocal laser scanning microscopy with spatiotemporal structured illumination.

    PubMed

    Gao, Peng; Nienhaus, G Ulrich

    2016-03-15

    Confocal laser scanning microscopy (CLSM), which is widely utilized in the biological and biomedical sciences, is limited in spatial resolution due to diffraction to about half the light wavelength. Here we have combined structured illumination with CLSM to enhance its spatial resolution. To this end, we have used a spatial light modulator (SLM) to generate fringe patterns of different orientations and phase shifts in the excitation spot without any mechanical movement. We have achieved 1.8 and 1.7 times enhanced lateral and axial resolutions, respectively, by synthesizing the object spectrum along different illumination directions. This technique is thus a promising tool for high-resolution morphological or fluorescence imaging, especially in deep tissue. PMID:26977667

  8. Point-to-plane registration of terrestrial laser scans

    NASA Astrophysics Data System (ADS)

    Grant, Darion; Bethel, James; Crawford, Melba

    2012-08-01

    The registration of pairs of Terrestrial Laser Scanning data (TLS) is an integral precursor to 3D data analysis. Of specific interest in this research work is the class of approaches that is considered to be fine registration and which does not require any targets or tie points. This paper presents a pairwise fine registration approach called P2P that is formulated using the General Least Squares adjustment model. Given some initial registration parameters, the proposed P2P approach utilizes the scanned points and estimated planar features of both scans, along with their stochastic properties. These quantities are used to determine the optimum registration parameters in the least squares sense. The proposed P2P approach was tested on both simulated and real TLS data, and experimental results showed it to be four times more accurate than the registration approach of Chen and Medioni (1991).

  9. Road Orthophoto/dtm Generation from Mobile Laser Scanning

    NASA Astrophysics Data System (ADS)

    Vallet, B.; Papelard, J.-P.

    2015-08-01

    This paper proposes a pipeline to produce road orthophoto and DTM from Mobile Laser Scanning (MLS). For the ortho, modern laser scanners provide a reflectance information allowing for high quality grayscale images, at a much finer resolution than aerial photography can offer. For DTM, MLS offers a much higher accuracy and density than aerial products. This increased precision and resolution leverages new applications for both ortho and DEM. The first task is to filter ground vs non ground, then an interpolation is conducted to build image tiles from the filtered points. Finally, multiple layers are registered and blended to allow for seamless fusion. Our proposed approach achieves high quality products and scaling up is demonstrated.

  10. Hot Slab Surface Inspection By Laser Scanning Method

    NASA Astrophysics Data System (ADS)

    Matsubara, Toshiro; Toyota, Toshio; Fujiyama, Akihiro

    1986-10-01

    An optical flaw detector with laser as the external light source, which is called LST ( laser scanning tester ), has been developed. This equipment automatically inspects the entire surface of hot slabs. The results are used to examine the suitability of those slabs for hot charge rolling. The characteristics of LST are its high optical resolving power and the signal processing method with which two-dimensional information on the type of the flaw is processed. For the opening width of O.4mm and over, the detection ratio is nearly 100%. This equipment started commercial operation in January 1983 in Nippon Steel's Yawata Works and its application has increased the hot charge rolling ratio.

  11. Non-Contact Measurement Using A Laser Scanning Probe

    NASA Astrophysics Data System (ADS)

    Modjarrad, Amir

    1989-03-01

    Traditional high accuracy touch-trigger probing can now be complemented by high speed, non-contact, profile scanning to give another "dimension" to the three-dimensional Co-ordinate Measuring Machines (CMMs). Some of the features of a specially developed laser scanning probe together with the trade-offs involved in the design of inspection systems that use triangulation are examined. Applications of such a laser probe on CMMs are numerous since high speed scanning allows inspection of many different components and surfaces. For example, car body panels, tyre moulds, aircraft wing skins, turbine blades, wax and clay models, plastics, etc. Other applications include in-process surveillance in manufacturing and food processing, robotics vision and many others. Some of these applications are discussed and practical examples, case studies and experimental results are given with particular reference to use on CMMs. In conclusion, future developments and market trends in high speed non-contact measurement are discussed.

  12. Boresight alignment method for mobile laser scanning systems

    NASA Astrophysics Data System (ADS)

    Rieger, P.; Studnicka, N.; Pfennigbauer, M.; Zach, G.

    2010-06-01

    Mobile laser scanning (MLS) is the latest approach towards fast and cost-efficient acquisition of 3-dimensional spatial data. Accurately evaluating the boresight alignment in MLS systems is an obvious necessity. However, recent systems available on the market may lack of suitable and efficient practical workflows on how to perform this calibration. This paper discusses an innovative method for accurately determining the boresight alignment of MLS systems by employing 3D laser scanners. Scanning objects using a 3D laser scanner operating in a 2D line-scan mode from various different runs and scan directions provides valuable scan data for determining the angular alignment between inertial measurement unit and laser scanner. Field data is presented demonstrating the final accuracy of the calibration and the high quality of the point cloud acquired during an MLS campaign.

  13. Gravel-bed surface roughness from airborne laser scanning

    NASA Astrophysics Data System (ADS)

    Huang, G.; Wang, C.

    2011-12-01

    The roughness of gravel-bed surface is of great importance for fluvial geomorpholoy. Numerous studies have demonstrated that the fractal theory and the log-log variogram are useful for describing the multi-scaling behavior(grain scale and form scale) of the gravel-bed surface. In this study, we obtained the 3D surface information of the gravel surface of a central bar in Nan-Shih River, Taiwan using an airborne laser scanning with a nominal point density of 100 points/m2. The data were divided into 6m × 6m grids. The roughness characteristics of the gravel bar were discussed using the anisotropy axes (also called the directions of maximum and minimum continuity, respectively) determined from the variogram map for each grid. And, the fractal dimension of the two directions were also calculated.

  14. Airborne Laser Scanning and Image Processing Techniques for Archaeological Prospection

    NASA Astrophysics Data System (ADS)

    Faltýnová, M.; Nový, P.

    2014-06-01

    Aerial photography was, for decades, an invaluable tool for archaeological prospection, in spite of the limitation of this method to deforested areas. The airborne laser scanning (ALS) method can be nowadays used to map complex areas and suitable complement earlier findings. This article describes visualization and image processing methods that can be applied on digital terrain models (DTMs) to highlight objects hidden in the landscape. Thanks to the analysis of visualized DTM it is possible to understand the landscape evolution including the differentiation between natural processes and human interventions. Different visualization methods were applied on a case study area. A system of parallel tracks hidden in a forest and its surroundings - part of old route called "Devil's Furrow" near the town of Sázava was chosen. The whole area around well known part of Devil's Furrow has not been prospected systematically yet. The data from the airborne laser scanning acquired by the Czech Office for Surveying, Mapping and Cadastre was used. The average density of the point cloud was approximately 1 point/m2 The goal of the project was to visualize the utmost smallest terrain discontinuities, e.g. tracks and erosion furrows, which some were not wholly preserved. Generally we were interested in objects that are clearly not visible in DTMs displayed in the form of shaded relief. Some of the typical visualization methods were tested (shaded relief, aspect and slope image). To get better results we applied image-processing methods that were successfully used on aerial photographs or hyperspectral images in the past. The usage of different visualization techniques on one site allowed us to verify the natural character of the southern part of Devil's Furrow and find formations up to now hidden in the forests.

  15. Test field for airborne laser scanning in Finland

    NASA Astrophysics Data System (ADS)

    Ahokas, E.; Kaartinen, H.; Kukko, A.; Litkey, P.

    2014-11-01

    Airborne laser scanning (ALS) is a widely spread operational measurement tool for obtaining 3D coordinates of the ground surface. There is a need for calibrating the ALS system and a test field for ALS was established at the end of 2013. The test field is situated in the city of Lahti, about 100 km to the north of Helsinki. The size of the area is approximately 3.5 km × 3.2 km. Reference data was collected with a mobile laser scanning (MLS) system assembled on a car roof. Some streets were measured both ways and most of them in one driving direction only. The MLS system of the Finnish Geodetic Institute (FGI) consists of a navigation system (NovAtel SPAN GNSS-IMU) and a laser scanner (FARO Focus3D 120). In addition to the MLS measurements more than 800 reference points were measured using a Trimble R8 VRS-GNSS system. Reference points are along the streets, on parking lots, and white pedestrian crossing line corners which can be used as reference targets. The National Land Survey of Finland has already used this test field this spring for calibrating their Leica ALS-70 scanner. Especially it was easier to determine the encoder scale factor parameter using this test field. Accuracy analysis of the MLS points showed that the point height RMSE is 2.8 cm and standard deviation is 2.6 cm. Our purpose is to measure both more MLS data and more reference points in the test field area to get a better spatial coverage. Calibration flight heights are planned to be 1000 m and 2500 m above ground level. A cross pattern, southwest-northeast and northwest-southeast, will be flown both in opposite directions.

  16. Urban Tree Classification Using Full-Waveform Airborne Laser Scanning

    NASA Astrophysics Data System (ADS)

    Koma, Zs.; Koenig, K.; Höfle, B.

    2016-06-01

    Vegetation mapping in urban environments plays an important role in biological research and urban management. Airborne laser scanning provides detailed 3D geodata, which allows to classify single trees into different taxa. Until now, research dealing with tree classification focused on forest environments. This study investigates the object-based classification of urban trees at taxonomic family level, using full-waveform airborne laser scanning data captured in the city centre of Vienna (Austria). The data set is characterised by a variety of taxa, including deciduous trees (beeches, mallows, plane trees and soapberries) and the coniferous pine species. A workflow for tree object classification is presented using geometric and radiometric features. The derived features are related to point density, crown shape and radiometric characteristics. For the derivation of crown features, a prior detection of the crown base is performed. The effects of interfering objects (e.g. fences and cars which are typical in urban areas) on the feature characteristics and the subsequent classification accuracy are investigated. The applicability of the features is evaluated by Random Forest classification and exploratory analysis. The most reliable classification is achieved by using the combination of geometric and radiometric features, resulting in 87.5% overall accuracy. By using radiometric features only, a reliable classification with accuracy of 86.3% can be achieved. The influence of interfering objects on feature characteristics is identified, in particular for the radiometric features. The results indicate the potential of using radiometric features in urban tree classification and show its limitations due to anthropogenic influences at the same time.

  17. Estimation of big sagebrush leaf area index with terrestrial laser scanning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A remote-sensing technique is need to bridge the gap between airborne laser scanning (ALS) and ground-based field techniques for accurately assessing leaf area index (LAI) in sparsely vegetated landscapes like sagebrush steppe. Terrestrial laser scanning (TLS) was used to measure structural variable...

  18. Mobile Laser Scanning Geodesy: a Complement to Space-based Methods

    NASA Astrophysics Data System (ADS)

    Brooks, B. A.; Glennie, C. L.

    2014-12-01

    Mobile Laser Scanning (MLS) is an emerging tool that permits autonomous and rapid high-resolution imaging of the surface expression of fault slip. Here, we explore the possibility that MLS geodesy can complement GNSS and InSAR geodetic studies of fault-related deformation. We are particularly interested in transient slip aspects of the earthquake cycle - quasi-continuous creep and post-earthquake afterslip, for example - that have proven elusive to study with other geodetic methods because of their spatially and/or temporally punctuated occurrence. We envision and test two manners of performing MLS geodesy: (1) MLS data referenced to legacy Airborne Laser Scanning (ALS) data sets and (2) MLS data referenced to other MLS data sets collected from a moving automobile. From 2012 to 2014, we collected multiple MLS data sets from a creeping section of Northern California's Hayward fault near Fremont, CA; the area was also imaged in the 2007 EarthScope regional ALS survey. The study area is a suburban, residential neighborhood and was chosen, in part, so that we could utilize the stability and geometric regularity of built structures as virtual control points in the geodetic analysis. Our analysis derived an estimated offset by a least squares rigid body transformation of planar surfaces from structural features common to each data set. For the ALS-MLS technique this presents a complication because ALS data image mostly house roofs whereas MLS data image a combination of roofs and vertical walls. Using TLS (Terrestrial Laser Scanning) data as ground truth, we find that both ALS-MLS and MLS-MLS techniques have relative accuracy capability of measuring surface fault slip at the ~1cm/yr level. Furthermore, we find good agreement between independently measured creep and the ALS-MLS derived measurement of ~6 cm over 6 years. We discuss the promise of extending this pilot work to cover a much larger portion of the Hayward fault as well as the implications and challenges related

  19. High capacity aerodynamic air bearing (HCAB) for laser scanning applications

    NASA Astrophysics Data System (ADS)

    Coleman, Sean M.

    2005-08-01

    A high capacity aerodynamic air bearing (HCAB) has been developed for the laser scanning market. The need for increasing accuracies in the prepress and print plate-making market is causing a shift from ball bearing to air bearing scanners. Aerostatic air bearings are a good option to meet this demand for better performance however, these bearings tend to be expensive and require an additional air supply, filtering and drying system. Commercially available aerodynamic bearings have been typically limited to small mirrors, on the order of 3.5" diameter and less than 0.5" thick. A large optical facet, hence a larger mirror, is required to generate the high number of pixels needed for this type of application. The larger optic necessitated the development of a high capacity 'self-generating' or aerodynamic air bearing that would meet the needs of the optical scanning market. Its capacity is rated up to 6.0" diameter and 1.0" thick optics. The performance of an aerodynamic air bearing is better than a ball bearing and similar to an aerostatic air bearing. It retains the low costs while eliminating the need for ancillary equipment required by an aerostatic bearing.

  20. Delineation of individual tree crowns for mobile laser scanning data

    NASA Astrophysics Data System (ADS)

    Wu, Rosen; Chen, Yiping; Wen, Chenglu; Wang, Cheng; Li, Jonathan

    2016-03-01

    The information of individual trees plays an important role in urban surveying and mapping. With the development of Light Detection and Ranging (LiDAR) technology, 3-Dimenisonal (3D) structure of trees can be generated in point clouds with high spatial resolution and accuracy. Individual tree segmentations are used to derive tree structural attributes such as tree height, crown diameter, stem position etc. In this study, a framework is proposed to take advantage of the detailed structures of tree crowns which are represented in the mobile laser scanning (MLS) data. This framework consists of five steps: (1) Automatically detect and remove ground points using RANSAC; (2) Compress all the above ground points to image grid with 3D knowledge reserved; (3) Simplify and remove unqualified grids; (4) Find tree peaks using a heuristic searching method; (5) Delineate the individual tree crowns by applying a modified watershed method. In an experiment on the point clouds on Xiamen Island, China, individual tree crowns from MLS point cloud data are successfully extracted.

  1. Filtering method for 3D laser scanning point cloud

    NASA Astrophysics Data System (ADS)

    Liu, Da; Wang, Li; Hao, Yuncai; Zhang, Jun

    2015-10-01

    In recent years, with the rapid development of the hardware and software of the three-dimensional model acquisition, three-dimensional laser scanning technology is utilized in various aspects, especially in space exploration. The point cloud filter is very important before using the data. In the paper, considering both the processing quality and computing speed, an improved mean-shift point cloud filter method is proposed. Firstly, by analyze the relevance of the normal vector between the upcoming processing point and the near points, the iterative neighborhood of the mean-shift is selected dynamically, then the high frequency noise is constrained. Secondly, considering the normal vector of the processing point, the normal vector is updated. Finally, updated position is calculated for each point, then each point is moved in the normal vector according to the updated position. The experimental results show that the large features are retained, at the same time, the small sharp features are also existed for different size and shape of objects, so the target feature information is protected precisely. The computational complexity of the proposed method is not high, it can bring high precision results with fast speed, so it is very suitable for space application. It can also be utilized in civil, such as large object measurement, industrial measurement, car navigation etc. In the future, filter with the help of point strength will be further exploited.

  2. Multispectral Analysis of Indigenous Rock Art Using Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Skoog, B.; Helmholz, P.; Belton, D.

    2016-06-01

    Multispectral analysis is a widely used technique in the photogrammetric and remote sensing industry. The use of Terrestrial Laser Scanning (TLS) in combination with imagery is becoming increasingly common, with its applications spreading to a wider range of fields. Both systems benefit from being a non-contact technique that can be used to accurately capture data regarding the target surface. Although multispectral analysis is actively performed within the spatial sciences field, its extent of application within an archaeological context has been limited. This study effectively aims to apply the multispectral techniques commonly used, to a remote Indigenous site that contains an extensive gallery of aging rock art. The ultimate goal for this research is the development of a systematic procedure that could be applied to numerous similar sites for the purpose of heritage preservation and research. The study consisted of extensive data capture of the rock art gallery using two different TLS systems and a digital SLR camera. The data was combined into a common 2D reference frame that allowed for standard image processing to be applied. An unsupervised k-means classifier was applied to the multiband images to detect the different types of rock art present. The result was unsatisfactory as the subsequent classification accuracy was relatively low. The procedure and technique does however show potential and further testing with different classification algorithms could possibly improve the result significantly.

  3. Automatic analysis for neuron by confocal laser scanning microscope

    NASA Astrophysics Data System (ADS)

    Satou, Kouhei; Aoki, Yoshimitsu; Mataga, Nobuko; Hensh, Takao K.; Taki, Katuhiko

    2005-12-01

    The aim of this study is to develop a system that recognizes both the macro- and microscopic configurations of nerve cells and automatically performs the necessary 3-D measurements and functional classification of spines. The acquisition of 3-D images of cranial nerves has been enabled by the use of a confocal laser scanning microscope, although the highly accurate 3-D measurements of the microscopic structures of cranial nerves and their classification based on their configurations have not yet been accomplished. In this study, in order to obtain highly accurate measurements of the microscopic structures of cranial nerves, existing positions of spines were predicted by the 2-D image processing of tomographic images. Next, based on the positions that were predicted on the 2-D images, the positions and configurations of the spines were determined more accurately by 3-D image processing of the volume data. We report the successful construction of an automatic analysis system that uses a coarse-to-fine technique to analyze the microscopic structures of cranial nerves with high speed and accuracy by combining 2-D and 3-D image analyses.

  4. Street environment change detection from mobile laser scanning point clouds

    NASA Astrophysics Data System (ADS)

    Xiao, Wen; Vallet, Bruno; Brédif, Mathieu; Paparoditis, Nicolas

    2015-09-01

    Mobile laser scanning (MLS) has become a popular technique for road inventory, building modelling, infrastructure management, mobility assessment, etc. Meanwhile, due to the high mobility of MLS systems, it is easy to revisit interested areas. However, change detection using MLS data of street environment has seldom been studied. In this paper, an approach that combines occupancy grids and a distance-based method for change detection from MLS point clouds is proposed. Unlike conventional occupancy grids, our occupancy-based method models space based on scanning rays and local point distributions in 3D without voxelization. A local cylindrical reference frame is presented for the interpolation of occupancy between rays according to the scanning geometry. The Dempster-Shafer theory (DST) is utilized for both intra-data evidence fusion and inter-data consistency assessment. Occupancy of reference point cloud is fused at the location of target points and then the consistency is evaluated directly on the points. A point-to-triangle (PTT) distance-based method is combined to improve the occupancy-based method. Because it is robust to penetrable objects, e.g. vegetation, which cause self-conflicts when modelling occupancy. The combined method tackles irregular point density and occlusion problems, also eliminates false detections on penetrable objects.

  5. Multispectral Airborne Laser Scanning for Automated Map Updating

    NASA Astrophysics Data System (ADS)

    Matikainen, Leena; Hyyppä, Juha; Litkey, Paula

    2016-06-01

    During the last 20 years, airborne laser scanning (ALS), often combined with multispectral information from aerial images, has shown its high feasibility for automated mapping processes. Recently, the first multispectral airborne laser scanners have been launched, and multispectral information is for the first time directly available for 3D ALS point clouds. This article discusses the potential of this new single-sensor technology in map updating, especially in automated object detection and change detection. For our study, Optech Titan multispectral ALS data over a suburban area in Finland were acquired. Results from a random forests analysis suggest that the multispectral intensity information is useful for land cover classification, also when considering ground surface objects and classes, such as roads. An out-of-bag estimate for classification error was about 3% for separating classes asphalt, gravel, rocky areas and low vegetation from each other. For buildings and trees, it was under 1%. According to feature importance analyses, multispectral features based on several channels were more useful that those based on one channel. Automatic change detection utilizing the new multispectral ALS data, an old digital surface model (DSM) and old building vectors was also demonstrated. Overall, our first analyses suggest that the new data are very promising for further increasing the automation level in mapping. The multispectral ALS technology is independent of external illumination conditions, and intensity images produced from the data do not include shadows. These are significant advantages when the development of automated classification and change detection procedures is considered.

  6. Multi-Pass Approach for Mobile Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Nolan, J.; Eckels, R.; Evers, M.; Singh, R.; Olsen, M. J.

    2015-08-01

    Mobile Terrestrial Laser Scanning (MTLS) has been utilised for an increasing number of corridor surveys. Current MTLS surveys require that many targets be placed along the corridor to monitor the MTLS trajectory's accuracy. These targets enable surveyors to directly evaluate the magnitude of GNSS errors at regular intervals and can also be used to adjust the trajectory to the survey control. However, this "Multi-Target" approach (MTA) is an onerous task that can significantly reduce efficiency. It also is inconvenient to the travelling public, as lanes are often blocked and traffic slowed to permit surveyors to work safely along the road corridor. This paper introduces a "Multi-Pass" approach (MPA), which minimises the number of targets required for monitoring the GNSS-controlled trajectory while still maintaining strict engineering accuracies. MPA uses the power of multiple, independent MTLS passes with different GNSS constellations to generate a "Control Polyline" from the point cloud for the corridor. The Control Polyline can be considered as a statistically valid survey measurement and be incorporated in a network adjustment to strengthen a control network by identifying outliers. Results from a test survey at the MTLS course maintained by the Oregon Department of Transportation illustrate the effectiveness of this approach.

  7. Hierarchical extraction of urban objects from mobile laser scanning data

    NASA Astrophysics Data System (ADS)

    Yang, Bisheng; Dong, Zhen; Zhao, Gang; Dai, Wenxia

    2015-01-01

    Point clouds collected in urban scenes contain a huge number of points (e.g., billions), numerous objects with significant size variability, complex and incomplete structures, and variable point densities, raising great challenges for the automated extraction of urban objects in the field of photogrammetry, computer vision, and robotics. This paper addresses these challenges by proposing an automated method to extract urban objects robustly and efficiently. The proposed method generates multi-scale supervoxels from 3D point clouds using the point attributes (e.g., colors, intensities) and spatial distances between points, and then segments the supervoxels rather than individual points by combining graph based segmentation with multiple cues (e.g., principal direction, colors) of the supervoxels. The proposed method defines a set of rules for merging segments into meaningful units according to types of urban objects and forms the semantic knowledge of urban objects for the classification of objects. Finally, the proposed method extracts and classifies urban objects in a hierarchical order ranked by the saliency of the segments. Experiments show that the proposed method is efficient and robust for extracting buildings, streetlamps, trees, telegraph poles, traffic signs, cars, and enclosures from mobile laser scanning (MLS) point clouds, with an overall accuracy of 92.3%.

  8. Estimation of forest parameters using airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Cohen, J.

    2015-12-01

    Methods for the estimation of forest characteristics by airborne laser scanning (ALS) data have been introduced by several authors. Tree height (TH) and canopy closure (CC) describing the forest properties can be used in forest, construction and industry applications, as well as research and decision making. The National Land Survey has been collecting ALS data from Finland since 2008 to generate a nationwide high resolution digital elevation model. Although this data has been collected in leaf-off conditions, it still has the potential to be utilized in forest mapping. A method where this data is used for the estimation of CC and TH in the boreal forest region is presented in this paper. Evaluation was conducted in eight test areas across Finland by comparing the results with corresponding Multi-Source National Forest Inventory (MS-NFI) datasets. The ALS based CC and TH maps were generally in a good agreement with the MS-NFI data. As expected, deciduous forests caused some underestimation in CC and TH, but the effect was not major in any of the test areas. The processing chain has been fully automated enabling fast generation of forest maps for different areas.

  9. Pedestrian Detection by Laser Scanning and Depth Imagery

    NASA Astrophysics Data System (ADS)

    Barsi, A.; Lovas, T.; Molnar, B.; Somogyi, A.; Igazvolgyi, Z.

    2016-06-01

    Pedestrian flow is much less regulated and controlled compared to vehicle traffic. Estimating flow parameters would support many safety, security or commercial applications. Current paper discusses a method that enables acquiring information on pedestrian movements without disturbing and changing their motion. Profile laser scanner and depth camera have been applied to capture the geometry of the moving people as time series. Procedures have been developed to derive complex flow parameters, such as count, volume, walking direction and velocity from laser scanned point clouds. Since no images are captured from the faces of pedestrians, no privacy issues raised. The paper includes accuracy analysis of the estimated parameters based on video footage as reference. Due to the dense point clouds, detailed geometry analysis has been conducted to obtain the height and shoulder width of pedestrians and to detect whether luggage has been carried or not. The derived parameters support safety (e.g. detecting critical pedestrian density in mass events), security (e.g. detecting prohibited baggage in endangered areas) and commercial applications (e.g. counting pedestrians at all entrances/exits of a shopping mall).

  10. Laser Scanning System for Pressure and Temperature Paints

    NASA Technical Reports Server (NTRS)

    Sullivan, John

    1997-01-01

    Acquiring pressure maps of aerodynamic surfaces is very important for improving and validating the performance of aerospace vehicles. Traditional pressure measurements are taken with pressure taps embedded in the model surface that are connected to transducers. While pressure taps allow highly accurate measurements to be acquired, they do have several drawbacks. Pressure taps do not give good spatial resolution due to the need for individual pressure tubes, compounded by limited space available inside models. Also, building a model proves very costly if taps are needed because of the large amount of labor necessary to drill, connect and test each one. The typical cost to install one tap is about $200. Recently, a new method for measuring pressure on aerodynamic surfaces has been developed utilizing a technology known as pressure sensitive paints (PSP). Using PSP, pressure distributions can be acquired optically with high spatial resolution and simple model preparation. Flow structures can be easily visualized using PSP, but are missed using low spatial resolution arrays of pressure taps. PSP even allows pressure distributions to be found on rotating machinery where previously this has been extremely difficult or even impossible. The goal of this research is to develop a laser scanning system for use with pressure sensitive paints that allows accurate pressure measurements to be obtained on various aerodynamic surfaces ranging from wind tunnel models to high speed jet engine compressor blades.

  11. Laser scanning dental probe for endodontic root canal treatment

    NASA Astrophysics Data System (ADS)

    Blank, Molly A. B.; Friedrich, Michal; Hamilton, Jeffrey D.; Lee, Peggy; Berg, Joel; Seibel, Eric J.

    2011-03-01

    Complications that arise during endodontic procedures pose serious threats to the long-term integrity and health of the tooth. Potential complexities of root canals include residual pulpal tissue, cracks, mesial-buccal 2 and accessory canals. In the case of a failed root canal, a successful apicoectomy can be jeopardized by isthmuses, accessory canals, and root microfracture. Confirming diagnosis using a small imaging probe would allow proper treatment and prevent retreatment of endodontic procedures. An ultrathin and flexible laser scanning endoscope of 1.2 to 1.6mm outer diameter was used in vitro to image extracted teeth with varied root configurations. Teeth were opened using a conventional bur and high speed drill. Imaging within the opened access cavity clarified the location of the roots where canal filing would initiate. Although radiographs are commonly used to determine the root canal size, position, and shape, the limited 2D image perspective leaves ambiguity that could be clarified if used in conjunction with a direct visual imaging tool. Direct visualization may avoid difficulties in locating the root canal and reduce the number of radiographs needed. A transillumination imaging device with the separated illumination and light collection functions rendered cracks visible in the prepared teeth that were otherwise indiscernible using reflected visible light. Our work demonstrates that a small diameter endoscope with high spatial resolution may significantly increase the efficiency and success of endodontic procedures.

  12. Quantification of telomere length by FISH and laser scanning cytometry

    NASA Astrophysics Data System (ADS)

    Mahoney, John E.; Sahin, Ergun; Jaskelioff, Mariela; Chin, Lynda; DePinho, Ronald A.; Protopopov, Alexei I.

    2008-02-01

    Telomeres play a critical role in the maintenance of chromosomal stability. Telomere erosion, coupled with loss of DNA damage checkpoint function, results in genomic instability that promotes the development of cancer. The critical role of telomere dynamics in cancer has motivated the development of technologies designed to monitor telomere reserves in a highly quantitative and high-throughput manner in humans and model organisms. To this end, we have adapted and modified two established technologies, telomere-FISH and laser scanning cytometry. Specifically, we have produced a number of enhancements to the iCys LSC (CompuCyte) package including software updates, use of 60X dry objectives, and increased spatial resolution by 0.2 um size of stage steps. In addition, the 633 nm HeNe laser was replaced with a 532 nm green diode laser to better match the viewing options. Utilization of telomere-deficient mouse cells with short dysfunctional telomeres and matched telomerase reconstituted cultures demonstrated significantly higher mean integral specific fluorescence values for mTR transfectants relative to empty vector controls: 4.485M vs. 1.362M (p<0.0001). Histograms of average telomere intensities for individual cells were obtained and demonstrated intercellular heterogeneity in telomere lengths. The validation of the approach derives from a strong correlation between iCys LSC values and Southern blotting. This validated method greatly increases our experimental throughput and objectivity.

  13. Footprint Map Partitioning Using Airborne Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Xiong, B.; Oude Elberink, S.; Vosselman, G.

    2016-06-01

    Nowadays many cities and countries are creating their 3D building models for a better daily management and smarter decision making. The newly created 3D models are required to be consistent with existing 2D footprint maps. Thereby the 2D maps are usually combined with height data for the task of 3D reconstruction. Many buildings are often composed by parts that are discontinuous over height. Building parts can be reconstructed independently and combined into a complete building. Therefore, most of the state-of-the-art work on 3D building reconstruction first decomposes a footprint map into parts. However, those works usually change the footprint maps for easier partitioning and cannot detect building parts that are fully inside the footprint polygon. In order to solve those problems, we introduce two methodologies, one more dependent on height data, and the other one more dependent on footprints. We also experimentally evaluate the two methodologies and compare their advantages and disadvantages. The experiments use Airborne Laser Scanning (ALS) data and two vector maps, one with 1:10,000 scale and another one with 1:500 scale.

  14. Detection of windthrown trees using airborne laser scanning

    NASA Astrophysics Data System (ADS)

    Nyström, Mattias; Holmgren, Johan; Fransson, Johan E. S.; Olsson, Håkan

    2014-08-01

    In this study, a method has been developed for the detection of windthrown trees under a forest canopy, using the difference between two elevation models created from the same high density (65 points/m2) airborne laser scanning data. The difference image showing objects near the ground was created by subtracting a standard digital elevation model (DEM) from a more detailed DEM created using an active surface algorithm. Template matching was used to automatically detect windthrown trees in the difference image. The 54 ha study area is located in hemi-boreal forest in southern Sweden (Lat. 58°29‧ N, Long. 13°38‧ E) and is dominated by Norway spruce (Picea abies) with 3.5% deciduous species (mostly birch) and 1.7% Scots pine (Pinus sylvestris). The result was evaluated using 651 field measured windthrown trees. At individual tree level, the detection rate was 38% with a commission error of 36%. Much higher detection rates were obtained for taller trees; 89% of the trees taller than 27 m were detected. For pine the individual tree detection rate was 82%, most likely due to the more easily visible stem and lack of branches. When aggregating the results to 40 m square grid cells, at least one tree was detected in 77% of the grid cells which according to the field measurements contained one or more windthrown trees.

  15. Globally consistent registration of terrestrial laser scans via graph optimization

    NASA Astrophysics Data System (ADS)

    Theiler, Pascal Willy; Wegner, Jan Dirk; Schindler, Konrad

    2015-11-01

    In this paper we present a framework for the automatic registration of multiple terrestrial laser scans. The proposed method can handle arbitrary point clouds with reasonable pairwise overlap, without knowledge about their initial orientation and without the need for artificial markers or other specific objects. The framework is divided into a coarse and a fine registration part, which each start with pairwise registration and then enforce consistent global alignment across all scans. While we put forward a complete, functional registration system, the novel contribution of the paper lies in the coarse global alignment step. Merging multiple scans into a consistent network creates loops along which the relative transformations must add up. We pose the task of finding a global alignment as picking the best candidates from a set of putative pairwise registrations, such that they satisfy the loop constraints. This yields a discrete optimization problem that can be solved efficiently with modern combinatorial methods. Having found a coarse global alignment in this way, the framework proceeds by pairwise refinement with standard ICP, followed by global refinement to evenly spread the residual errors. The framework was tested on six challenging, real-world datasets. The discrete global alignment step effectively detects, removes and corrects failures of the pairwise registration procedure, finally producing a globally consistent coarse scan network which can be used as initial guess for the highly non-convex refinement. Our overall system reaches success rates close to 100% at acceptable runtimes < 1 h, even in challenging conditions such as scanning in the forest.

  16. Laser Scanning in Engineering Surveying: Methods of Measurement and Modeling of Structures

    NASA Astrophysics Data System (ADS)

    Lenda, Grzegorz; Uznański, Andrzej; Strach, Michał; Lewińska, Paulina

    2016-06-01

    The study is devoted to the uses of laser scanning in the field of engineering surveying. It is currently one of the main trends of research which is developed at the Department of Engineering Surveying and Civil Engineering at the Faculty of Mining Surveying and Environmental Engineering of AGH University of Science and Technology in Krakow. They mainly relate to the issues associated with tower and shell structures, infrastructure of rail routes, or development of digital elevation models for a wide range of applications. These issues often require the use of a variety of scanning techniques (stationary, mobile), but the differences also regard the planning of measurement stations and methods of merging point clouds. Significant differences appear during the analysis of point clouds, especially when modeling objects. Analysis of the selected parameters is already possible basing on ad hoc measurements carried out on a point cloud. However, only the construction of three-dimensional models provides complete information about the shape of structures, allows to perform the analysis in any place and reduces the amount of the stored data. Some structures can be modeled in the form of simple axes, sections, or solids, for others it becomes necessary to create sophisticated models of surfaces, depicting local deformations. The examples selected for the study allow to assess the scope of measurement and office work for a variety of uses related to the issue set forth in the title of this study. Additionally, the latest, forward-looking technology was presented - laser scanning performed from Unmanned Aerial Vehicles (drones). Currently, it is basically in the prototype phase, but it might be expected to make a significant progress in numerous applications in the field of engineering surveying.

  17. Tree Height Growth Measurement with Single-Scan Airborne, Static Terrestrial and Mobile Laser Scanning

    PubMed Central

    Lin, Yi; Hyyppä, Juha; Kukko, Antero; Jaakkola, Anttoni; Kaartinen, Harri

    2012-01-01

    This study explores the feasibility of applying single-scan airborne, static terrestrial and mobile laser scanning for improving the accuracy of tree height growth measurement. Specifically, compared to the traditional works on forest growth inventory with airborne laser scanning, two issues are regarded: “Can the new technique characterize the height growth for each individual tree?” and “Can this technique refine the minimum growth-discernable temporal interval further?” To solve these two puzzles, the sampling principles of the three laser scanning modes were first examined, and their error sources against the task of tree-top capturing were also analyzed. Next, the three-year growths of 58 Nordic maple trees (Crimson King) for test were intermittently surveyed with one type of laser scanning each time and then analyzed by statistics. The evaluations show that the height growth of each individual tree still cannot be reliably characterized even by single-scan terrestrial laser scanning, and statistical analysis is necessary in this scenario. After Gaussian regression, it is found that the minimum temporal interval with distinguishable tree height growths can be refined into one month based on terrestrial laser scanning, far better than the two years deduced in the previous works based on airborne laser scanning. The associated mean growth was detected to be about 0.12 m. Moreover, the parameter of tree height generally under-estimated by airborne and even mobile laser scanning can be relatively revised by means of introducing static terrestrial laser scanning data. Overall, the effectiveness of the proposed technique is primarily validated. PMID:23112743

  18. Tree Classification with Fused Mobile Laser Scanning and Hyperspectral Data

    PubMed Central

    Puttonen, Eetu; Jaakkola, Anttoni; Litkey, Paula; Hyyppä, Juha

    2011-01-01

    Mobile Laser Scanning data were collected simultaneously with hyperspectral data using the Finnish Geodetic Institute Sensei system. The data were tested for tree species classification. The test area was an urban garden in the City of Espoo, Finland. Point clouds representing 168 individual tree specimens of 23 tree species were determined manually. The classification of the trees was done using first only the spatial data from point clouds, then with only the spectral data obtained with a spectrometer, and finally with the combined spatial and hyperspectral data from both sensors. Two classification tests were performed: the separation of coniferous and deciduous trees, and the identification of individual tree species. All determined tree specimens were used in distinguishing coniferous and deciduous trees. A subset of 133 trees and 10 tree species was used in the tree species classification. The best classification results for the fused data were 95.8% for the separation of the coniferous and deciduous classes. The best overall tree species classification succeeded with 83.5% accuracy for the best tested fused data feature combination. The respective results for paired structural features derived from the laser point cloud were 90.5% for the separation of the coniferous and deciduous classes and 65.4% for the species classification. Classification accuracies with paired hyperspectral reflectance value data were 90.5% for the separation of coniferous and deciduous classes and 62.4% for different species. The results are among the first of their kind and they show that mobile collected fused data outperformed single-sensor data in both classification tests and by a significant margin. PMID:22163894

  19. Single tree biomass modelling using airborne laser scanning

    NASA Astrophysics Data System (ADS)

    Kankare, Ville; Räty, Minna; Yu, Xiaowei; Holopainen, Markus; Vastaranta, Mikko; Kantola, Tuula; Hyyppä, Juha; Hyyppä, Hannu; Alho, Petteri; Viitala, Risto

    2013-11-01

    Accurate forest biomass mapping methods would provide the means for e.g. detecting bioenergy potential, biofuel and forest-bound carbon. The demand for practical biomass mapping methods at all forest levels is growing worldwide, and viable options are being developed. Airborne laser scanning (ALS) is a promising forest biomass mapping technique, due to its capability of measuring the three-dimensional forest vegetation structure. The objective of the study was to develop new methods for tree-level biomass estimation using metrics derived from ALS point clouds and to compare the results with field references collected using destructive sampling and with existing biomass models. The study area was located in Evo, southern Finland. ALS data was collected in 2009 with pulse density equalling approximately 10 pulses/m2. Linear models were developed for the following tree biomass components: total, stem wood, living branch and total canopy biomass. ALS-derived geometric and statistical point metrics were used as explanatory variables when creating the models. The total and stem biomass root mean square error per cents equalled 26.3% and 28.4% for Scots pine (Pinus sylvestris L.), and 36.8% and 27.6% for Norway spruce (Picea abies (L.) H. Karst.), respectively. The results showed that higher estimation accuracy for all biomass components can be achieved with models created in this study compared to existing allometric biomass models when ALS-derived height and diameter were used as input parameters. Best results were achieved when adding field-measured diameter and height as inputs in the existing biomass models. The only exceptions to this were the canopy and living branch biomass estimations for spruce. The achieved results are encouraging for the use of ALS-derived metrics in biomass mapping and for further development of the models.

  20. Practical Enhancement of Terrestrial Laser Scanning for Fluvial Geomorphology Surveys

    NASA Astrophysics Data System (ADS)

    Hwang, K.; Chandler, D. G.

    2014-12-01

    Accurate measurement of microtopography plays an important role in fluvial geomorphology. Whereof the surface is obscured by vegetation or landform, airborne remote sensing can be impractical and ground-based surveys using terrestrial laser scanning (TLS) show promise. TLS provides high resolution observations of the land surface for relatively low cost and with simple setup. However, the scanning range is effectively limited to less than 100 m, requiring individual scenes to be merged in software to represent larger landforms. For studies requiring several scenes, an efficient scanning strategy should be established in advance to optimize for time, resolution and spatial coverage. This requires careful consideration of scanner placement to merge scenes. We address problems encountered with blind spots. TLS is generally conducted on a 2-m (or shorter) tripod and the low scanning angle to the land surface at long distance inevitably causes blind spots in rugose or complex terrain. Similarly, the distance between TLS placement points is limited by the ability to resolve matching targets from sequential surveys. Here we present a simple geometry-based scanning plan regardless of the type and range of the instrument, with modification of the survey instrument platform. The half of a minimum range is used to make at least 18% of a superposed area with the next scan. Since scanning height barely affects the scanning range, the tripod was substituted to a 3-m stepladder and the platform of the scanner was modified to level and adjust the device easily with one hand. The results show that the new scanning plan performs well regardless of the topography and figure of the area of interest, with sufficient superposed area for combination with other adjacent scans. The modification of the platform also turned out to be more efficient to secure the observing angle and improve usability. The physical enhancement for TLS will provide valuable opportunity to conduct a standardized

  1. Evaluation of Terrestrial Laser Scanning for Rice Growth Monitoring

    NASA Astrophysics Data System (ADS)

    Tilly, N.; Hoffmeister, D.; Liang, H.; Cao, Q.; Liu, Y.; Lenz-Wiedemann, V.; Miao, Y.; Bareth, G.

    2012-08-01

    The rapidly growing world population and the resulting pressure on the efficiency of agriculture require a sustainable development of intensive field management with regard to natural resources. In this context, the use of non-destructive remote sensing technologies to monitor status and change detection of plant growth is in the focus of research and application. In this contribution, we evaluate the applicability of multitemporal terrestrial laser scanning (TLS) for rice growth monitoring. The test sites are located around Jiansanjiang in Heilongjiang Province in the far northeast of China. The focus of the field experiment was on different nitrogen fertilizer inputs during the growing period in 2011. To realize the monitoring approach, three campaigns were carried out during the vegetative stage of rice plants. For all campaigns the terrestrial laser scanner Riegl VZ-1000 was used. The achieved knowledge can be described in two parts. First, for each date the variability of plant height and biomass is detectable for the whole experiment field and - more important - between the plots. Furthermore, differences in height and biomass related to edge effects can be investigated for every single plot. The spatial distribution is visualized by Crop Surface Models (CSM), which are digital surface models with a high resolution and accuracy achieved by the interpolation of the 3D point clouds. Secondly, the multitemporal surveying approach enables the monitoring of the growth rate of the rice plants. Additionally, it is possible to detect and analyze as well the spatial distribution of the changes by comparing the CSMs. Our results show that TLS is a suitable and promising method for rice growth monitoring. Furthermore, the contemporaneous surveying with other sensors enables us to validate our measurements and bares opportunities for further enhancements.

  2. The use of laser scanning confocal microscopy (LSCM) in materials science.

    PubMed

    Hovis, D B; Heuer, A H

    2010-12-01

    Laser scanning confocal microscopes are essential and ubiquitous tools in the biological, biochemical and biomedical sciences, and play a similar role to scanning electron microscopes in materials science. However, modern laser scanning confocal microscopes have a number of advantages for the study of materials, in addition to their obvious uses for high resolution reflected and transmitted light optical microscopy. In this paper, we provide several examples that exploit the laser scanning confocal microscope's capabilities of pseudo-infinite depth of field imaging, topographic imaging, photo-stimulated luminescence imaging and Raman spectroscopic imaging. PMID:21077878

  3. Laser Scanning-Assisted Tip-Enhanced Optical Microscopy for Robust Optical Nanospectroscopy.

    PubMed

    Yano, Taka-Aki; Tsuchimoto, Yuta; Mochizuki, Masahito; Hayashi, Tomohiro; Hara, Masahiko

    2016-07-01

    Laser-scanning-assisted tip-enhanced optical microscopy was developed for robust optical nanospectroscopy. The laser-scanning system was utilized to automatically set and keep the center of a tight laser-focusing spot in the proximity of a metallic tip with around 10 nm precision. This enabled us to efficiently and stably induce plasmon-coupled field enhancement at the apex of the metallic probe tip. The laser-scanning technique was also applied to tracking and compensating the thermal drift of the metallic tip in the spot. This technique is usable for long-term tip-enhanced optical spectroscopy without any optical degradation. PMID:27412187

  4. Combining microtomy and confocal laser scanning microscopy for structural analyses of plant-fungus associations.

    PubMed

    Rath, Magnus; Grolig, Franz; Haueisen, Janine; Imhof, Stephan

    2014-05-01

    The serious problem of extended tissue thickness in the analysis of plant-fungus associations was overcome using a new method that combines physical and optical sectioning of the resin-embedded sample by microtomy and confocal microscopy. Improved tissue infiltration of the fungal-specific, high molecular weight fluorescent probe wheat germ agglutinin conjugated to Alexa Fluor® 633 resulted in high fungus-specific fluorescence even in deeper tissue sections. If autofluorescence was insufficient, additional counterstaining with Calcofluor White M2R or propidium iodide was applied in order to visualise the host plant tissues. Alternatively, the non-specific fluorochrome acid fuchsine was used for rapid staining of both, the plant and the fungal cells. The intricate spatial arrangements of the plant and fungal cells were preserved by immobilization in the hydrophilic resin Unicryl™. Microtomy was used to section the resin-embedded roots or leaves until the desired plane was reached. The data sets generated by confocal laser scanning microscopy of the remaining resin stubs allowed the precise spatial reconstruction of complex structures in the plant-fungus associations of interest. This approach was successfully tested on tissues from ectomycorrhiza (Betula pendula), arbuscular mycorrhiza (Galium aparine; Polygala paniculata, Polygala rupestris), ericoid mycorrhiza (Calluna vulgaris), orchid mycorrhiza (Limodorum abortivum, Serapias parviflora) and on one leaf-fungus association (Zymoseptoria tritici on Triticum aestivum). The method provides an efficient visualisation protocol applicable with a wide range of plant-fungus symbioses. PMID:24249491

  5. The Investigation of Accuracy of 3 Dimensional Models Generated From Point Clouds with Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Gumus, Kutalmis; Erkaya, Halil

    2013-04-01

    In Terrestrial laser scanning (TLS) applications, it is necessary to take into consideration the conditions that affect the scanning process, especially the general characteristics of the laser scanner, geometric properties of the scanned object (shape, size, etc.), and its spatial location in the environment. Three dimensional models obtained with TLS, allow determining the geometric features and relevant magnitudes of the scanned object in an indirect way. In order to compare the spatial location and geometric accuracy of the 3-dimensional model created by Terrestrial laser scanning, it is necessary to use measurement tools that give more precise results than TLS. Geometric comparisons are performed by analyzing the differences between the distances, the angles between surfaces and the measured values taken from cross-sections between the data from the 3-dimensional model created with TLS and the values measured by other measurement devices The performance of the scanners, the size and shape of the scanned objects are tested using reference objects the sizes of which are determined with high precision. In this study, the important points to consider when choosing reference objects were highlighted. The steps up to processing the point clouds collected by scanning, regularizing these points and modeling in 3 dimensions was presented visually. In order to test the geometric correctness of the models obtained by Terrestrial laser scanners, sample objects with simple geometric shapes such as cubes, rectangular prisms and cylinders that are made of concrete were used as reference models. Three dimensional models were generated by scanning these reference models with Trimble Mensi GS 100. The dimension of the 3D model that is created from point clouds was compared with the precisely measured dimensions of the reference objects. For this purpose, horizontal and vertical cross-sections were taken from the reference objects and generated 3D models and the proximity of

  6. Diffusion of photoacid generators by laser scanning confocal microscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Ping L.; Webber, Stephen E.; Mendenhall, J.; Byers, Jeffrey D.; Chao, Keith K.

    1998-06-01

    Diffusion of the photogenerated acid during the period of time between exposure and development can cause contrast loss and ultimately loss of the latent image. This is especially relevant for chemically amplified photoresists that require a post-exposure baking step, which in turn facilitates acid diffusion due to the high temperature normally employed. It is thus important to develop techniques with good spatial resolution to monitor the photogeneration of acid. More precisely, we need techniques that provide two distinct types of information: spatial resolution on various length scales within the surface layer and also sufficient depth resolution so that one can observe the transition from very surface layer to bulk structure in the polymer blend coated on silicon substrate. Herein laser scanning confocal microscopy is used to evaluate the resist for the first time. We report the use of the confocal microscopy to map the pag/dye distribution in PHS matrices, with both reflectance images and fluorescence images. A laser beam is focused onto a small 3D volume element, termed a voxel. It is typically 200 nm X 200 nm laterally and 800 nm axially. The illuminated voxel is viewed such that only signals emanating from this voxel are detected, i.e., signal from outside the probed voxel is not detected. By adjusting the vertical position of the laser focal point, the voxel can be moved to the designated lateral plane to produce an image. Contrast caused by topology difference between the exposed and unexposed area can be eliminated. Bis-p-butylphenyl iodonium triflat (7% of polyhydroxystyrene) is used as photoacid generators. 5% - 18% (by weight, PHS Mn equals 13 k) resist in PGMEA solution is spin cast onto the treated quartz disk with thickness of 1.4 micrometers , 5 micrometers space/10 micrometers pitch chrome mask is used to generate the pattern with mercury DUV illumination. Fluoresceinamine, the pH-sensitive dye, is also used to enhance the contrast of

  7. Estimation of terracing characteristics from airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Kokalj, Žiga

    2015-04-01

    Agricultural terraces are a fundamental morphological form of the Slovenian landscape. They are present in all of its diverse geographical regions, from Mediterranean and Dinaric hills and plateaus, Alpine mountains and plains, to Pannonian hills. New systematic research based on mapping aerial orthophotos and historical maps revealed previously unrecorded distribution and extent of terracing. However, the extensive overgrowing of the Slovenian countryside in the past century, when forest cover has grown from 40% to more than 60%, hid many of the terraces under a thick forest canopy. This is especially true for the higher and more remote areas where unfavourable natural conditions have coupled with depopulation processes. In such conditions, the only reasonable technique to observe cultural terraces and other remains of past human activities over large areas is airborne laser scanning. With the country-wide airborne lidar data becoming available, many new possibilities for discovery as well as quantitative analyses are becoming available. We explored manual and semiautomatic approaches to obtain terracing characteristics around representative villages of diverse landscape types. Individual terraces can be described with several attributes, such as riser slope gradient, riser height, tread area, length and width, ratio of length and width, altitude, location of the terrace in the thermal band, distance to the settlement, number and type of trees, distance between trees, and number of vineyard rows. Such characteristics can be derived manually, which can be painstakingly slow, but with relative precisions reaching the order of centimetres and decimetres, or semiautomatically, which is much faster, but with worse precision levels, mainly due to various outliers and errors in processing. The success of attribute derivation is highly dependent on raw lidar data acquisition parameters and processing. Manual interpretation has a distinct advantage of the possibility to

  8. Geodetic Imaging of Marsh Surface Elevation with Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Nguyen, C. T.; Starek, M. J.; Gibeaut, J. C.; Lord, A.

    2015-12-01

    The resilience of marshes to a rising sea is dependent on their elevation response. Given the level of precision required to measure minute changes in marsh elevation over time, survey methods have to be adapted to minimize impacts to the sediment surface. Current approaches include Surface Elevation Tables (SETs), which are used to monitor wetland surface change with respect to an in situ vertical benchmark. Although SETs have been proven as an effective technique to track subtle sedimentation rates (< 1 cm/year), they provide a single-point measurement construed to a location with limited to no information on the spatial pattern in marsh elevation response away from the measurement site. Terrestrial Laser Scanning (TLS) offers potential for high definition monitoring of marsh surface evolution. However, several challenges must be overcome in the application of the technology for geodetic imaging of marsh surfaces. These challenges include surface occlusion by dense vegetation, error propagation due to scan co-registration and referencing across time, impacts of scan angle, and filtering of non-ground points. Researchers at Texas A&M University-Corpus Christi conducted a field-survey of a marsh within the Grand Bay National Estuarine Research Reserve using TLS and RTK GPS for comparison. Grand Bay in Mississippi USA is one of the most biologically productive estuarine ecosystems in the Gulf of Mexico. The study region is covered by dense and tall saw-grass that makes it a challenging environment for bare-earth mapping. For this survey, a Riegl VZ-400 TLS (1550 nm wavelength) was utilized. The system is capable of recording multiple returns per a transmitted pulse (up to 15) and provides full-waveform output for signal post-processing to extract returns. The objectives of the study are twofold: 1) examine impacts of TLS survey design, scan angle and scan density on marsh elevation mapping; 2) assess the capabilities of multiple-echo and full-waveform TLS data to

  9. Development of an Online Archive for Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Crosby, Christopher; Lowry, Ben; McWhirter, Jeff; Phillips, David; Meertens, Chuck

    2013-04-01

    The UNAVCO Geodetic Imaging program provides terrestrial laser scanning (TLS) support to the Earth science research community through a TLS instrumentation pool of five scanners, field engineering, data processing, and technical training. As part of this community TLS support role, UNAVCO is responsible for generation of level one (L1) TLS data products and TLS data archive and access. A UNAVCO-organized and US National Science Foundation-funded TLS community workshop held October 2011 in Boulder, Colorado defined many of the challenges and requirements a TLS data archive and access system must address. TLS data acquisition presents unique challenges for metadata, provenance capture, and data archive. TLS datasets are often large and level zero (L0 - raw) data are stored in a variety of proprietary formats, requiring conversion and standardization for access and exchange. Due to the wide range of scientific and engineering objectives that motivate TLS data collection, field methods and collection techniques vary greatly and must be thoroughly documented in project metadata. These challenges make data and metadata capture, preservation, and provenance important objectives for an online TLS archive. To address these challenges, UNAVCO is developing a TLS archive based on the open source RAMADDA platform (http://ramadda.org). The UNAVCO TLS archive will provide online archive of L0 and L1 data products, capture field metadata and data processing workflows for provenance, and store original georeferencing information. In addition, the TLS repository provides on-demand services for simple point cloud visualization, data sub-setting and thinning, and file format (e.g., LAS, ASCII, proprietary) data conversion. The system also offers automation of RINEX processing of GPS data, OPUS and CSRS submission and solution ingestion, and generation of control point lists to streamline georeferencing of TLS point cloud data. Georeferencing metadata and GPS file provenance are

  10. Using airborne laser scanning profiles to validate marine geoid models

    NASA Astrophysics Data System (ADS)

    Julge, Kalev; Gruno, Anti; Ellmann, Artu; Liibusk, Aive; Oja, Tõnis

    2014-05-01

    Airborne laser scanning (ALS) is a remote sensing method which utilizes LiDAR (Light Detection And Ranging) technology. The datasets collected are important sources for large range of scientific and engineering applications. Mostly the ALS is used to measure terrain surfaces for compilation of Digital Elevation Models but it can also be used in other applications. This contribution focuses on usage of ALS system for measuring sea surface heights and validating gravimetric geoid models over marine areas. This is based on the ALS ability to register echoes of LiDAR pulse from the water surface. A case study was carried out to analyse the possibilities for validating marine geoid models by using ALS profiles. A test area at the southern shores of the Gulf of Finland was selected for regional geoid validation. ALS measurements were carried out by the Estonian Land Board in spring 2013 at different altitudes and using different scan rates. The one wavelength Leica ALS50-II laser scanner on board of a small aircraft was used to determine the sea level (with respect to the GRS80 reference ellipsoid), which follows roughly the equipotential surface of the Earth's gravity field. For the validation a high-resolution (1'x2') regional gravimetric GRAV-GEOID2011 model was used. This geoid model covers the entire area of Estonia and surrounding waters of the Baltic Sea. The fit between the geoid model and GNSS/levelling data within the Estonian dry land revealed RMS of residuals ±1… ±2 cm. Note that such fitting validation cannot proceed over marine areas. Therefore, an ALS observation-based methodology was developed to evaluate the GRAV-GEOID2011 quality over marine areas. The accuracy of acquired ALS dataset were analyzed, also an optimal width of nadir-corridor containing good quality ALS data was determined. Impact of ALS scan angle range and flight altitude to obtainable vertical accuracy were investigated as well. The quality of point cloud is analysed by cross

  11. Application to monitoring of tailings dam based on 3D laser scanning technology

    NASA Astrophysics Data System (ADS)

    Ren, Fang; Zhang, Aiwu

    2011-06-01

    This paper presented a new method of monitoring of tailing dam based on 3D laser scanning technology and gave the method flow of acquiring and processing the tailing dam data. Taking the measured data for example, the author analyzed the dam deformation by generating the TIN, DEM and the curvature graph, and proved that it's feasible to global monitor the tailing dam using 3D laser scanning technology from the theory and method.

  12. Stop-and-Go Mode: Sensor Manipulation as Essential as Sensor Development in Terrestrial Laser Scanning

    PubMed Central

    Lin, Yi; Hyyppä, Juha; Kukko, Antero

    2013-01-01

    This study was dedicated to illustrating the significance of sensor manipulation in the case of terrestrial laser scanning, which is a field now in quick development. In fact, this quickness was mainly rooted in the emergence of new sensors with better performance, while the implications of sensor manipulation have not been fully recognized by the whole community. For this technical gap, the stop-and-go mapping mode can be reckoned as one of the potential solution plans. Stop-and-go was first proposed to handle the low efficiency of traditional static terrestrial laser scanning, and then, it was re-emphasized to improve the stability of sample collections for the state-of-the-art technology of mobile laser scanning. This work reviewed the previous efforts of trying the stop-and-go mode for improving the performance of static and mobile terrestrial laser scanning and generalized their principles respectively. This work also analyzed its advantages compared to the fully-static and fully-kinematic terrestrial laser scanning, and suggested the plans with more automatic measures for raising the efficacy of terrestrial laser scanning. Overall, this literature review indicated that the stop-and-go mapping mode as a case with generic sense can verify the presumption of sensor manipulation as essential as sensor development. PMID:23799493

  13. Three-dimensional imaging of the intact mouse cochlea by fluorescent laser scanning confocal microscopy.

    PubMed

    MacDonald, Glen H; Rubel, Edwin W

    2008-09-01

    The complex anatomy of the mammalian cochlea is most readily understood by representation in three-dimensions. However, the cochlea is often sectioned to minimize the effects of its anatomic complexity and optical properties on image acquisition by light microscopy. We have found that optical aberrations present in the decalcified cochlea can be greatly reduced by dehydration through graded ethanols followed by clearing with a mixture of five parts methyl salicylate and three parts benzyl benzoate (MSBB). Clearing the cochlea with MSBB enables acquisition of high-resolution images with multiple fluorescent labels, through the full volume of the cochlea by laser scanning confocal microscopy. The resulting images are readily applicable to three-dimensional morphometric analysis and volumetric visualizations. This method promises to be particularly useful for three-dimensional characterization of anatomy, innervation and expression of genes or proteins in the many new animal models of hearing and balance generated by genetic manipulation. Furthermore, the MSBB is compatible with most non-protein fluorophores used for histological labeling, and may be removed with traditional transitional solvents to allow subsequent epoxy embedding for sectioning. PMID:18573326

  14. Terrestrial Laser Scanning for Quantifying Habitat and Hydraulic Complexity Measures: A Comparison with Traditional Surveying Techniques

    NASA Astrophysics Data System (ADS)

    Resop, J. P.; Kozarek, J. L.; Hession, W. C.

    2010-12-01

    Accurate stream topography measurement is important for many ecological applications such as hydraulic modeling and habitat characterization. Measures of habitat complexity are often difficult to quantify or are performed qualitatively. Traditional surveying with a total station can be time intensive and limited by poor spatial resolution. These problems lead to measurement and interpolation errors, which propagate to model uncertainty. Terrestrial laser scanning (TLS) has the potential to measure topography at a high resolution and accuracy. Two methods, total station surveying and TLS, were used to measure a 100-m forested reach on the Staunton River in Shenandoah National Park, VA, USA. The TLS dataset was post-processed to remove vegetation and create a 2-cm digital elevation model (DEM). The position and size of ten rocks were compared for each method. An algorithm was developed for delineating rocks within the stream channel from the TLS DEM. Ecological metrics based on the structural complexity of the stream, such as percent in-stream rock cover and cross-sectional heterogeneity, were derived from the TLS dataset for six habitat areas and compared with the estimates from traditional methods. Compared to TLS, total station surveying underestimated rock volume and cross-sectional heterogeneity by 55% and 41%, respectively. TLS has the potential to quantify habitat complexity measures in an automated, unbiased manner.

  15. Processing of airborne laser scanning data to generate accurate DTM for floodplain wetland

    NASA Astrophysics Data System (ADS)

    Szporak-Wasilewska, Sylwia; Mirosław-Świątek, Dorota; Grygoruk, Mateusz; Michałowski, Robert; Kardel, Ignacy

    2015-10-01

    Structure of the floodplain, especially its topography and vegetation, influences the overland flow and dynamics of floods which are key factors shaping ecosystems in surface water-fed wetlands. Therefore elaboration of the digital terrain model (DTM) of a high spatial accuracy is crucial in hydrodynamic flow modelling in river valleys. In this study the research was conducted in the unique Central European complex of fens and marshes - the Lower Biebrza river valley. The area is represented mainly by peat ecosystems which according to EU Water Framework Directive (WFD) are called "water-dependent ecosystems". Development of accurate DTM in these areas which are overgrown by dense wetland vegetation consisting of alder forest, willow shrubs, reed, sedges and grass is very difficult, therefore to represent terrain in high accuracy the airborne laser scanning data (ALS) with scanning density of 4 points/m2 was used and the correction of the "vegetation effect" on DTM was executed. This correction was performed utilizing remotely sensed images, topographical survey using the Real Time Kinematic positioning and vegetation height measurements. In order to classify different types of vegetation within research area the object based image analysis (OBIA) was used. OBIA allowed partitioning remotely sensed imagery into meaningful image-objects, and assessing their characteristics through spatial and spectral scale. The final maps of vegetation patches that include attributes of vegetation height and vegetation spectral properties, utilized both the laser scanning data and the vegetation indices developed on the basis of airborne and satellite imagery. This data was used in process of segmentation, attribution and classification. Several different vegetation indices were tested to distinguish different types of vegetation in wetland area. The OBIA classification allowed correction of the "vegetation effect" on DTM. The final digital terrain model was compared and examined

  16. Hyperscale Morphological Models of Braided Rivers: Multi-scale retrievals with Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Brasington, J.; Vericat, D.; Rychov, I.

    2008-12-01

    In the last decade, advances in topographic survey and digital elevation modelling have enabled a revolution in the study of river morphology and fluvial processes. Prior to the late 1990s, the analysis of channel form and dynamics was typically restricted to inferences from cross-sections and planform mapping. Since then, advances in survey instrumentation (e.g., Brasington et al., 2000) and remote sensing (Westaway et al., 2000; Brasington et al., 2003; Charlton et al., 2003) have enabled the collection of dense topographic data and the opportunity to build high-resolution, precision DEMs, ideally suited to morphometric analysis, sediment budgeting and as boundary models for fluid simulations. Continuing developments in survey technology are now poised to reset the parameters of this field once again through the recent emergence of ruggedized, terrestrial laser scanners. Based on time-of-flight or phase-based laser ranging, these instruments are capable of acquiring unprecedented volumes of survey-grade observations at operating frequencies of between 5-500 kHz and over ranges 25-1000 m. This new technology offers the potential to acquire rapidly, reach-scale datasets which record topographic information at the resolution of bed grain-scale upwards. This hitherto unprecedented data-stream presents new opportunities for river science, but also creates significant challenges particularly associated with: data management; regularization of resolution; visualization; and data assimilation with parallel models and data- products. In this paper we present a new methodology designed to analyze large 3d point clouds generated by terrestrial laser scanning. Specifically, the approach generates multi-resolution gridded terrain products from scan data whilst retaining the sub-grid scale information as key statistical attributes. We apply the method to a 1 km reach of the River Feshie, Scotland which was scanned in 2007 and evaluate the results through a comparison with

  17. The application of dermal papillary rings in dermatology by in vivo confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Xiang, W. Z.; Xu, A. E.; Xu, J.; Bi, Z. G.; Shang, Y. B.; Ren, Q. S.

    2010-08-01

    Confocal laser scanning microscopy (CLSM) allows noninvasive visualization of human skin in vivo, without needing to fix or section the tissue. Melanocytes and pigmented keratinocytes at the level of the basal layer form bright dermal papillary rings which are readily amenable to identify in confocal images. Our purpose was to explore the role of dermal papillary rings in assessment of lesion location, the diagnosis, differential diagnosis of lesions and assessment of therapeutic efficacy by in vivo CLSM. Seventy-one patients were imaged with the VivaScope 1500 reflectance confocal microscope provided by Lucid, Inc. The results indicate that dermal papillary rings can assess the location of lesion; the application of dermal papillary rings can provide diagnostic support and differential diagnosis for vitiligo, nevus depigmentosus, tinea versicolor, halo nevus, common nevi, and assess the therapeutic efficacy of NBUVB phototherapy plus topical 0.1 percent tacrolimus ointment for vitiligo. In conclusion, our findings indicate that the dermal papillary rings play an important role in the assessment the location of lesion, diagnosis, differential diagnosis of lesions and assessment of therapeutic efficacy by in vivo CLSM. CLSM may be a promising tool for noninvasive examination in dermatology. However, larger studies are needed to expand the application of dermal papillary rings in dermatology.

  18. Confocal laser scanning microscopic investigation of ultrasonic, sonic, and rotary sealer placement techniques

    PubMed Central

    Nikhil, Vineeta; Singh, Renuka

    2013-01-01

    Background: Sealers are used to attain an impervious seal between the core material and root canal walls. Aim: To compare the depth and percentage of sealer penetration with three different placement techniques using confocal laser scanning microscopy as the evaluative tool. Materials and Methods: Root canals of 30 single-rooted teeth were prepared to a size of F3 and AH plus sealer with Rhodamine B was applied with Ultlrasonic file (Gr-1), lentulospiral (Gr-2), and Endoactivator (Gr-3). Canals were obturated with gutta-percha. The roots were sectioned at the 3 and 6-mm levels from the apical foramen and were examined on a confocal microscope. Results: A statistical significant differences among Gr-1, Gr-2, and Gr-3 were found at the 3 and 6-mm level (P < 0.05; ANOVA-Tukey tests) for the depth and percentage of sealer penetration except for Gr-1 and Gr-2 at 3-mm level. Gr-1 showed maximum mean depth of penetration (810 μm) and maximum mean percentage of sealer penetration (64.5) while Gr-3 showed minimum mean depth of penetration (112.7 μm) and minimum mean percentage of sealer penetration (26.7). Conclusion: Depth and percentage of penetration of sealer is influenced by the type of placement technique and by the root canal level with penetration decreasing apically. PMID:23956528

  19. Visualization and quantification of healthy and carious dentin structure using confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Kimura, Yuichi; Wilder-Smith, Petra B. B.; Krasieva, Tatiana B.; Arrastia-Jitosho, Anna-Marie A.; Liaw, Lih-Huei L.; Matsumoto, Koukichi; Berns, Michael W.

    1996-04-01

    In this study, a fluorescence technique was developed for visualization of dentin using confocal laser scanning microscopy (CLSM). Eighteen extracted human teeth were used: 13 showing no clinical signs of caries and 5 with visually apparent decay. Preliminary study: All teeth were horizontally sectioned to approx. 200 micrometers thickness and pre-treated as follows: no pretreatment; vacuum only; ultrasonication only; sodium hypochlorite (NaOCl) only; vacuum and NaOCl; ultrasonication and NaOCl; or vacuum, ultrasonication and NaOCl. Samples were stained with Rhodamine 123 fluorescent dye at a concentration of 10-5 M in phosphate buffer saline for 1 to 24 hours. Caries study: Dentin surfaces, some with pre-existing caries, were visualized using CLSM. Most dentin tubules in sound dentin appeared open using CLSM, but most dentin tubules in carious dentin appeared closed or narrowed. Surface images obtained using CLSM were similar to those seen by SEM, but additional subsurface imaging was possible using CLSM at depth intervals of 1 micrometers to a depth of 30 - 50 micrometers . This technique shows good potential for non-invasive surface and subsurface imaging of dentin structures.

  20. A statistical pixel intensity model for segmentation of confocal laser scanning microscopy images.

    PubMed

    Calapez, Alexandre; Rosa, Agostinho

    2010-09-01

    Confocal laser scanning microscopy (CLSM) has been widely used in the life sciences for the characterization of cell processes because it allows the recording of the distribution of fluorescence-tagged macromolecules on a section of the living cell. It is in fact the cornerstone of many molecular transport and interaction quantification techniques where the identification of regions of interest through image segmentation is usually a required step. In many situations, because of the complexity of the recorded cellular structures or because of the amounts of data involved, image segmentation either is too difficult or inefficient to be done by hand and automated segmentation procedures have to be considered. Given the nature of CLSM images, statistical segmentation methodologies appear as natural candidates. In this work we propose a model to be used for statistical unsupervised CLSM image segmentation. The model is derived from the CLSM image formation mechanics and its performance is compared to the existing alternatives. Results show that it provides a much better description of the data on classes characterized by their mean intensity, making it suitable not only for segmentation methodologies with known number of classes but also for use with schemes aiming at the estimation of the number of classes through the application of cluster selection criteria. PMID:20363677

  1. Evaluation of confocal laser scanning microscopy for enumeration of virus-like particles in aquatic systems

    PubMed Central

    Agis, Martin; Luef, Birgit

    2016-01-01

    Abstract Abundances of virus-like particles (VLPs, mostly bacteriophages) are high in aquatic environments; therefore, techniques for precise enumeration are essential in ecological monitoring. VLPs were determined after staining with SYBR Gold by conventional epifluorescence microscopy and compared to enumerations performed by confocal laser scanning microscopy (CLSM). In order to assess the potential of CLSM for viral direct counts (VDCs), we processed samples from different freshwater and marine systems. Optical sectioning by CLSM and production of an overlay picture of multiple scans enables the often uneven whole investigated filter area to be brought to the plane of focus. This allows for subsequent image analysis of digitally created high-quality images. Another advantage using the CLSM was that the short spot excitation of the stain via laser beam minimized fading of the stain. The VDC results show that there is no significant difference between the two methods. Regarding the known difficulties of viral abundance estimates on particulate material, CLSM was further applied to enumerate VLPs on a small set of marine transparent exopolymeric particles sampled from the Atlantic Ocean. Our data suggest that CLSM is a useful tool to count viruses in water samples as well as attached to certain types of aquatic aggregates. PMID:23108709

  2. Deformation Monitoring of Motorway Underpasses Using Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Puente, I.; González-Jorge, H.; Riveiro, B.; Arias, P.

    2012-07-01

    voussoirs ranging between 1 mm and 5 mm. These deformations are under the tolerances predicted by the structure and confirm the success in the construction works developed. The laser scanning and the post-processing algorithms here developed appear as an easy methodology to make deformation monitoring of underpass structures and guarantee the load capacity of the structure.

  3. Reliable fusion of knee bone laser scans to establish ground truth for cartilage thickness measurement

    NASA Astrophysics Data System (ADS)

    Chang, Ming-Ching; Trinh, Nhon H.; Fleming, Braden C.; Kimia, Benjamin B.

    2010-03-01

    We are interested in establishing ground truth data for validating morphology measurements of human knee cartilage from MR imaging. One promising approach is to compare the high-accuracy 3D laser scans of dissected cadaver knees before and after the dissolution of their cartilage. This requires an accurate and reliable method to fuse the individual laser scans from multiple views of the cadaver knees. Unfortunately existing methods using Iterative Closest Point (ICP) algorithm from off-the-shell packages often yield unreliable fusion results. We identify two major sources of variation: (i) the noise in depth measurements of the laser scans is significantly high and (ii) the use of point-to-point correspondence in ICP is not suitable due to sampling variation in the laser scans. We resolve the first problem by performing adaptive Gaussian smoothing on each individual laser scans prior to the fusion. For the second problem, we construct a surface mesh from the point cloud of each scan and adopt a point-to-mesh ICP scheme for pairwise alignment. The complete surface mesh is constructed by fusing all the scans in the order maximizing mutual overlaps. In experiments on 6 repeated scanning trials of a cadaver knee, our approach reduced the alignment error of point-to-point ICP by 30% and reduced coefficient of variation (CV) of cartilage thickness measurements from 5% down to 1.4%, significantly improving the method's repeatability.

  4. A novel quality control procedure for the evaluation of laser scanning data segmentation

    NASA Astrophysics Data System (ADS)

    Lari, Z.; Al-Durgham, K.; Habib, A.

    2014-11-01

    Over the past few years, laser scanning systems have been acknowledged as the leading tools for the collection of high density 3D point cloud over physical surfaces for many different applications. However, no interpretation and scene classification is performed during the acquisition of these datasets. Consequently, the collected data must be processed to extract the required information. The segmentation procedure is usually considered as the fundamental step in information extraction from laser scanning data. So far, various approaches have been developed for the segmentation of 3D laser scanning data. However, none of them is exempted from possible anomalies due to disregarding the internal characteristics of laser scanning data, improper selection of the segmentation thresholds, or other problems during the segmentation procedure. Therefore, quality control procedures are required to evaluate the segmentation outcome and report the frequency of instances of expected problems. A few quality control techniques have been proposed for the evaluation of laser scanning segmentation. These approaches usually require reference data and user intervention for the assessment of segmentation results. In order to resolve these problems, a new quality control procedure is introduced in this paper. This procedure makes hypotheses regarding potential problems that might take place in the segmentation process, detects instances of such problems, quantifies the frequency of these problems, and suggests possible actions to remedy them. The feasibility of the proposed approach is verified through quantitative evaluation of planar and linear/cylindrical segmentation outcome from two recently-developed parameter-domain and spatial-domain segmentation techniques.

  5. Assessment of DNA replication in central nervous system by Laser Scanning Cytometry

    NASA Astrophysics Data System (ADS)

    Lenz, Dominik; Mosch, Birgit; Bocsi, Jozsef; Arendt, Thomas; Tárnok, Attila

    2004-07-01

    μIn neurons of patients with Alzheimers's disease (AD) signs of cell cycle re-entry as well as polyploidy have been reported1, 2, indicating that the entire or a part of the genome of the neurons is duplicated before its death but mitosis is not initiated so that the cellular DNA content remains tetraploid. It was concluded, that this imbalance is the direct cause of the neuronal loss in AD3. Manual counting of polyploidal cells is possible but time consuming and possibly statistically insufficient. The aim of this study was to develop an automated method that detects the neuronal DNA content abnormalities with Laser Scanning Cytometry (LSC).Frozen sections of formalin-fixed brain tissue of AD patients and control subjects were labelled with anti-cyclin B and anti-NeuN antibodies. Immunolabelling was performed using Cy5- and Cy2-conjugated secondary antibodies and biotin streptavidin or tyramid signal amplification. In the end sections of 20m thickness were incubated with propidium iodide (PI) (50μg/ml) and covered on slides. For analysis by the LSC PI was used as trigger. Cells identified as neurons by NeuN expression were analyzed for cyclin B expression. Per specimen data of at least 10,000 neurons were acquired. In the frozen brain sections an automated quantification of the amount of nuclear DNA is possible with LSC. The DNA ploidy as well as the cell cycle distribution can be analyzed. A high number of neurons can be scanned and the duration of measuring is shorter than a manual examination. The amount of DNA is sufficiently represented by the PI fluorescence to be able to distinguish between eu- and polyploid neurons.

  6. [Laser scan microscopy: a new imaging procedure in quality assessment of artificial lenses].

    PubMed

    Rochels, R; Ziegler, E

    1989-01-01

    Laser-scan microscopy permits the evaluation of surfaces and deeper layers of an object by computer-assisted scanning with a laser beam. The reflected helium-neon or argon laser light is transmitted to a photodetector and after signal processing, to a frame store and a TV monitor. Imaging is realized by synchronous scanning and modulation of light intensity. Laser-scan microscopy revealed a smooth surface of both PMMA and HEMA lenses, whereas tears were detected in folded silicone implants. The physical and chemical homogeneity inside the three different materials was optimal. Compared to scanning electron microscopy, the quality of imaging is not as good with laser-scan microscopy. Nevertheless, one decisive advantage of the latter method is an analysis free of processing and artifacts, which permits a routine control of brand new and folded intraocular lenses. PMID:2722098

  7. Terrestrial laser scanning used to detect asymmetries in boat hulls

    NASA Astrophysics Data System (ADS)

    Roca-Pardiñas, Javier; López-Alvarez, Francisco; Ordóñez, Celestino; Menéndez, Agustín; Bernardo-Sánchez, Antonio

    2012-01-01

    We describe a methodology for identifying asymmetries in boat hull sections reconstructed from point clouds captured using a terrestrial laser scanner (TLS). A surface was first fit to the point cloud using a nonparametric regression method that permitted the construction of a continuous smooth surface. Asymmetries in cross-sections of the surface were identified using a bootstrap resampling technique that took into account uncertainty in the coordinates of the scanned points. Each reconstructed section was analyzed to check, for a given level of significance, that it was within the confidence interval for the theoretical symmetrical section. The method was applied to the study of asymmetries in a medium-sized yacht. Identified were differences of up to 5 cm between the real and theoretical sections in some parts of the hull.

  8. Reversible patterning of poly(methylmethacrylate) doped with disperse Red 1 by laser scanning

    SciTech Connect

    Tuma, J.; Lyutakov, O.; Huttel, I.; Slepicka, P.; Svorcik, V.

    2013-09-07

    Thin poly(methylmethacrylate) films doped by or covalently attached to disperse Red 1 acrylate (DR1) were patterned by laser scanning and simultaneous sample movement in confocal microscope. In both cases, periodical structure due to Marangoni effect is created. Modified polymers surfaces were analyzed by FTIR spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. After first stage of patterning, second stage with sample movement in perpendicular direction was applied. Depending on the method of DR1 dotation fishnet structure is obtained or pattern structure disappears. In the latter case, reversibility of pattern formation and erasure by laser scanning was studied.

  9. Missing link of sediment budget at a hillslope-channel transition: Application of terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Hiraoka, M.; Gomi, T.; Miyata, S.; Mizugaki, S.; Oda, T.; Uchiyama, Y.

    2013-12-01

    Sediment supply from the hillslope to stream channel is an important factor controlling timing and volume of sediment yield at the catchment outlet, and is often difficult to quantify. To examine the spatio-temporal variability of sediment supply at the catchment scale, we constructed a sediment budget for a small forested headwater catchment (7.0 ha) based on a coupled approach of field observations and terrestrial laser scanning (TLS). The sediment yield of the catchment was 2.1 t ha-1 yr-1 and an order of magnitude less than the yield from hillslopes. Based on the sediment budget, 85% of the sediment load from hillslopes can be stored at the hillslope/channel transition zone and in the channel. Comparison of grain size distributions between sediments collected from hillslopes and the catchment outlet showed that 10% of fine sediment (<2 mm in diameter) produced at the hillslopes was likely to be exported from the catchment as suspended sediment during storm events, while 30% of coarse sediment (>25 mm in diameter) produced at the hillslopes remained in the catchment. To investigate the magnitude of sediment supply and its distribution at the hillslope-channel transition, we used fine resolution TLS for a 50-m section of the hillslope/channel transitional zone. From two TLS surveys, conducted before and after the rainy season, 0.3 m resolution DEMs were created. Comparison of the DEMs of the study period showed that the ground vegetation cover in the hillslope/channel transitional zone spatially distributed, and was likely to affect the spatial patterns of sediment deposition at the bottom of hillslopes. Our coupled approach clarifies sediment supply and transport processes at the hillslope/channel transition associated with the spatial distribution of bank vegetation.

  10. Confocal laser-scanning microscopy for determining the structure of and keratinocyte infiltration through collagen sponges.

    PubMed

    Hanthamrongwit, M; Wilkinson, R; Osborne, C; Reid, W H; Grant, M H

    1996-03-01

    The development of artificial skin substitutes based on cultured cells and biomaterials such as collagen requires an understanding of cellular interactions with the substrate. In this study, human keratinocytes were cultured on the surface of collagen sponges, and confocal laser-scanning microscopy (CLSM) was used to assess both the microstructure of the sponge, and the cell morphology and distribution throughout the sponge. It was found that the pore size increased with increasing depth into the sponge. Both pore size and fiber thickness increased during incubation for up to 10 days at 37 degrees C in culture medium in the absence of cells. This latter effect was not observed when the sponges were incubated in distilled water. Keratinocytes penetrated into the sponge even after only 3 days in culture. By 10 days in culture, the cells had penetrated to the maximum depth that could be examined (120 microns from the sponge surface). In the presence of cells, the inner structure of the collagen sponge had altered after 10 days in culture, with the collagen fibers becoming thicker, and pore geometry less regular. The mechanism responsible for this is unknown at present. Although the presence of the keratinocytes increases distortion of the sponge structure, factors from the medium itself also contribute to this effect. CLSM is a powerful tool for assessing cellular interactions with bioimplants, providing both qualitative and quantitative information. It offers many advantages over scanning electron microscopy (SEM) and histological techniques. CLSM minimizes the time-consuming, extensive preparation of samples required with the latter two methods, and allows noninvasive serial optical sectioning of intact samples. PMID:8698696

  11. Orientation of Airborne Laser Scanning Point Clouds with Multi-View, Multi-Scale Image Blocks

    PubMed Central

    Rönnholm, Petri; Hyyppä, Hannu; Hyyppä, Juha; Haggrén, Henrik

    2009-01-01

    Comprehensive 3D modeling of our environment requires integration of terrestrial and airborne data, which is collected, preferably, using laser scanning and photogrammetric methods. However, integration of these multi-source data requires accurate relative orientations. In this article, two methods for solving relative orientation problems are presented. The first method includes registration by minimizing the distances between of an airborne laser point cloud and a 3D model. The 3D model was derived from photogrammetric measurements and terrestrial laser scanning points. The first method was used as a reference and for validation. Having completed registration in the object space, the relative orientation between images and laser point cloud is known. The second method utilizes an interactive orientation method between a multi-scale image block and a laser point cloud. The multi-scale image block includes both aerial and terrestrial images. Experiments with the multi-scale image block revealed that the accuracy of a relative orientation increased when more images were included in the block. The orientations of the first and second methods were compared. The comparison showed that correct rotations were the most difficult to detect accurately by using the interactive method. Because the interactive method forces laser scanning data to fit with the images, inaccurate rotations cause corresponding shifts to image positions. However, in a test case, in which the orientation differences included only shifts, the interactive method could solve the relative orientation of an aerial image and airborne laser scanning data repeatedly within a couple of centimeters. PMID:22454569

  12. MAMMALIAN APOPTOSIS IN WHOLE NEONATAL OVARIES USING CONFOCAL LASER SCANNING MICROSCOPY

    EPA Science Inventory

    MAMMALIAN APOPTOSIS IN WHOLE NEONATAL OVARIES USING CONFOCAL LASER SCANNING MICROSCOPY

    Robert M. Zucker Susan C. Jeffery and Sally D. Perreault

    Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Prot...

  13. Initial Tests and Accuracy Assesment of a Compact Mobile Laser Scanning System

    NASA Astrophysics Data System (ADS)

    Julge, K.; Ellmann, A.; Vajakas, T.; Kolka, R.

    2016-06-01

    Mobile laser scanning (MLS) is a faster and cost-effective alternative to static laser scanning, even though there is a slight trade-off in accuracy. This contribution describes a compact mobile laser scanning system mounted on a vehicle. The technical parameters of the used system components, i.e. a small LIDAR sensor Velodyne VLP-16 and a dual antenna GNSS/INS system Advanced Navigation Spatial Dual, are reviewed, along with the integration of these components for spatial data acquisition. Calculation principles of 3D coordinates from the real-time data of all the involved sensors are discussed. The field tests were carried out in a controlled environment of a parking lot and at different velocities. Experiments were carried out to test the ability of the GNSS/INS system to cope with difficult conditions, e.g. sudden movements due to cornering or swerving. The accuracy of the resulting MLS point cloud is evaluated with respect to high-accuracy static terrestrial laser scanning data. Problems regarding combining LIDAR, GNSS and INS sensors are outlined, as well as the initial accuracy assessments. Initial tests revealed errors related to insufficient quality of inertial data and a need for the trajectory post-processing calculations. Although this study was carried out while the system was mounted on a car, there is potential for operating the system on an unmanned aerial vehicle, all-terrain vehicle or in a backpack mode due to its relatively compact size.

  14. Evaluation of a laser scanning sensor for variable-rate tree sprayer development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate canopy measurement capabilities are prerequisites to automate variable-rate sprayers. A 270° radial range laser scanning sensor was tested for its scanning accuracy to detect tree canopy profiles. Signals from the laser sensor and a ground speed sensor were processed with an embedded comput...

  15. D Model of AL Zubarah Fortress in Qatar - Terrestrial Laser Scanning VS. Dense Image Matching

    NASA Astrophysics Data System (ADS)

    Kersten, T.; Mechelke, K.; Maziull, L.

    2015-02-01

    In September 2011 the fortress Al Zubarah, built in 1938 as a typical Arabic fortress and restored in 1987 as a museum, was recorded by the HafenCity University Hamburg using terrestrial laser scanning with the IMAGER 5006h and digital photogrammetry for the Qatar Museum Authority within the framework of the Qatar Islamic Archaeology and Heritage Project. One goal of the object recording was to provide detailed 2D/3D documentation of the fortress. This was used to complete specific detailed restoration work in the recent years. From the registered laser scanning point clouds several cuttings and 2D plans were generated as well as a 3D surface model by triangle meshing. Additionally, point clouds and surface models were automatically generated from digital imagery from a Nikon D70 using the open-source software Bundler/PMVS2, free software VisualSFM, Autodesk Web Service 123D Catch beta, and low-cost software Agisoft PhotoScan. These outputs were compared with the results from terrestrial laser scanning. The point clouds and surface models derived from imagery could not achieve the same quality of geometrical accuracy as laser scanning (i.e. 1-2 cm).

  16. Recommendations for the design and the installation of large laser scanning microscopy systems

    NASA Astrophysics Data System (ADS)

    Helm, P. Johannes

    2012-03-01

    Laser Scanning Microscopy (LSM) has since the inventions of the Confocal Scanning Laser Microscope (CLSM) and the Multi Photon Laser Scanning Microscope (MPLSM) developed into an essential tool in contemporary life science and material science. The market provides an increasing number of turn-key and hands-off commercial LSM systems, un-problematic to purchase, set up and integrate even into minor research groups. However, the successful definition, financing, acquisition, installation and effective use of one or more large laser scanning microscopy systems, possibly of core facility character, often requires major efforts by senior staff members of large academic or industrial units. Here, a set of recommendations is presented, which are helpful during the process of establishing large systems for confocal or non-linear laser scanning microscopy as an effective operational resource in the scientific or industrial production process. Besides the description of technical difficulties and possible pitfalls, the article also illuminates some seemingly "less scientific" processes, i.e. the definition of specific laboratory demands, advertisement of the intention to purchase one or more large systems, evaluation of quotations, establishment of contracts and preparation of the local environment and laboratory infrastructure.

  17. Penetration of tamoxifen citrate loaded ethosomes and liposomes across human skin: a comparative study with confocal laser scanning microscopy.

    PubMed

    Sarwa, Khomendra K; Suresh, Preeti K; Rudrapal, Mithun; Verma, Vinod K

    2014-01-01

    In the present study, ethosomal and liposomal formulations containing tamoxifen citrate were prepared and evaluated for their penetration properties in human cadaver skin using Franz diffusion cell and confocal laser scanning microscope (CLSM). The results clearly revealed that ethosomal vesicles showed a better drug permeation profile than that of liposomal vesicles. In addition, low fluorescence intensity in CLSM was recorded with liposomes as compared to ethosomes, indicating lower cumulative amount of drug permeation from liposomal vesicles. Furthermore, CLSM showed uniform fluorescence intensity across the entire depth of skin in ethosomal treatment, indicating high penetrability of ethosomal vesicles through human cadaver skin. In contrast, low penetrability of conventional liposomal vesicles was recorded as penetration was limited to the 7(th) section (i.e. upper epidermis layer) of skin as evident from visualization of intact liposomal vesicles in CLSM. PMID:24428443

  18. Microanalysis of dental caries using laser-scanned fluorescence

    NASA Astrophysics Data System (ADS)

    Barron, Joseph R.; Paton, Barry E.; Zakariasen, Kenneth L.

    1992-06-01

    It is well known that enamel and dentin fluoresce when illuminated by short-wavelength optical radiation. Fluorescence emission from carious and non-carious regions of teeth have been studied using a new experimental scanning technique for fluorescence analysis of dental sections. Scanning in 2 dimensions will allow surface maps of dental caries to be created. These surface images are then enhanced using the conventional and newer image processing techniques. Carious regions can be readily identified and contour maps can be used to graphically display the degree of damage on both surfaces and transverse sections. Numerous studies have shown that carious fluorescence is significantly different than non-carious regions. The scanning laser fluorescence spectrometer focuses light from a 25 mW He-Cd laser at 442 nm through an objective lens onto a cross-section area as small as 3 micrometers in diameter. Microtome prepared dental samples 100 micrometers thick are laid flat onto an optical bench perpendicular to the incident beam. The sample is moved under computer control in X & Y with an absolute precision of 0.1 micrometers . The backscattered light is both spatial and wavelength filtered before being measured on a long wavelength sensitized photomultiplier tube. High precision analysis of dental samples allow detailed maps of carious regions to be determined. Successive images allow time studies of caries growth and even the potential for remineralization studies of decalcified regions.

  19. A new method of building footprints detection using airborne laser scanning data and multispectral image

    NASA Astrophysics Data System (ADS)

    Luo, Yiping; Jiang, Ting; Gao, Shengli; Wang, Xin

    2010-10-01

    It presents a new approach for detecting building footprints in a combination of registered aerial image with multispectral bands and airborne laser scanning data synchronously obtained by Leica-Geosystems ALS40 and Applanix DACS-301 on the same platform. A two-step method for building detection was presented consisting of selecting 'building' candidate points and then classifying candidate points. A digital surface model(DSM) derived from last pulse laser scanning data was first filtered and the laser points were classified into classes 'ground' and 'building or tree' based on mathematic morphological filter. Then, 'ground' points were resample into digital elevation model(DEM), and a Normalized DSM(nDSM) was generated from DEM and DSM. The candidate points were selected from 'building or tree' points by height value and area threshold in nDSM. The candidate points were further classified into building points and tree points by using the support vector machines(SVM) classification method. Two classification tests were carried out using features only from laser scanning data and associated features from two input data sources. The features included height, height finite difference, RGB bands value, and so on. The RGB value of points was acquired by matching laser scanning data and image using collinear equation. The features of training points were presented as input data for SVM classification method, and cross validation was used to select best classification parameters. The determinant function could be constructed by the classification parameters and the class of candidate points was determined by determinant function. The result showed that associated features from two input data sources were superior to features only from laser scanning data. The accuracy of more than 90% was achieved for buildings in first kind of features.

  20. Improving particulate carbon loss estimates in eroding peatlands through the use of terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Grayson, R.; Holden, J.; Jones, R. R.; Carle, J. A.; Lloyd, A. R.

    2012-12-01

    Blanket bogs act as the largest terrestrial store of carbon within the UK. Unfortunately many are degraded with exacerbated erosion being common. Although considerable efforts have been made to quantify carbon fluxes across blanket bogs, less attention has focussed on quantifying losses associated with erosion. Traditional approaches to measuring erosion have relied on erosion pins and sediment traps. However, both methods suffer from several problems and are unable to provide data over large areas. Terrestrial laser scanning has been used widely in geomorphology to create detailed 3D topographic maps in a range of environments. A pilot study was carried out over winter 2010-2011 to test the applicability of terrestrial laser scanning to measure erosion across a blanket bog within the North Pennines, UK. The technique was found to be superior to traditional methods providing high resolution spatial data on surface elevation change. A net increase in the peat surface height of 2.5 mm was calculated from the terrestrial laser scans between October 2010 and March 2011. This compares with a net surface lowering of 38 mm measured using pins. These results suggest that previous erosion data from peatland sites based on pin measurements ought to be treated with caution. However, several improvements are required to the laser scanning technique before it is fully implemented in peatland environments including the development of a filter to remove vegetation from the scan results, and taking account of 'mire-breathing' which can cause surface level rise and fall in peatlands. It is clear that once these factors are dealt with, regular repeated ground based laser scanning will vastly improve our understanding of the role of processes that affect the surface elevation of peatlands including the relative roles of storm events and long-term seasonal cycles, and 'roughening' of the peat surface as a result of needle-ice formation, desiccation and wind-scouring.

  1. Laser Scanning for 3D Object Characterization: Infrastructure for Exploration and Analysis of Vegetation Signatures

    NASA Astrophysics Data System (ADS)

    Koenig, K.; Höfle, B.

    2012-04-01

    Mapping and characterization of the three-dimensional nature of vegetation is increasingly gaining in importance. Deeper insight is required for e.g. forest management, biodiversity assessment, habitat analysis, precision agriculture, renewable energy production or the analysis of interaction between biosphere and atmosphere. However the potential of 3D vegetation characterization has not been exploited so far and new technologies are needed. Laser scanning has evolved into the state-of-the-art technology for highly accurate 3D data acquisition. By now several studies indicated a high value of 3D vegetation description by using laser data. The laser sensors provide a detailed geometric presentation (geometric information) of scanned objects as well as a full profile of laser energy that was scattered back to the sensor (radiometric information). In order to exploit the full potential of these datasets, profound knowledge on laser scanning technology for data acquisition, geoinformation technology for data analysis and object of interest (e.g. vegetation) for data interpretation have to be joined. A signature database is a collection of signatures of reference vegetation objects acquired under known conditions and sensor parameters and can be used to improve information extraction from unclassified vegetation datasets. Different vegetation elements (leaves, branches, etc.) at different heights above ground with different geometric composition contribute to the overall description (i.e. signature) of the scanned object. The developed tools allow analyzing tree objects according to single features (e.g. echo width and signal amplitude) and to any relation of features and derived statistical values (e.g. ratio of laser point attributes). For example, a single backscatter cross section value does not allow for tree species determination, whereas the average echo width per tree segment can give good estimates. Statistical values and/or distributions (e.g. Gaussian

  2. Laser Scanning Measurements on Trees for Logging Harvesting Operations

    PubMed Central

    Zheng, Yili; Liu, Jinhao; Wang, Dian; Yang, Ruixi

    2012-01-01

    Logging harvesters represent a set of high-performance modern forestry machinery, which can finish a series of continuous operations such as felling, delimbing, peeling, bucking and so forth with human intervention. It is found by experiment that during the process of the alignment of the harvesting head to capture the trunk, the operator needs a lot of observation, judgment and repeated operations, which lead to the time and fuel losses. In order to improve the operation efficiency and reduce the operating costs, the point clouds for standing trees are collected with a low-cost 2D laser scanner. A cluster extracting algorithm and filtering algorithm are used to classify each trunk from the point cloud. On the assumption that every cross section of the target trunk is approximate a standard circle and combining the information of an Attitude and Heading Reference System, the radii and center locations of the trunks in the scanning range are calculated by the Fletcher-Reeves conjugate gradient algorithm. The method is validated through experiments in an aspen forest, and the optimized calculation time consumption is compared with the previous work of other researchers. Moreover, the implementation of the calculation result for automotive capturing trunks by the harvesting head during the logging operation is discussed in particular. PMID:23012543

  3. Laser scanning measurements on trees for logging harvesting operations.

    PubMed

    Zheng, Yili; Liu, Jinhao; Wang, Dian; Yang, Ruixi

    2012-01-01

    Logging harvesters represent a set of high-performance modern forestry machinery, which can finish a series of continuous operations such as felling, delimbing, peeling, bucking and so forth with human intervention. It is found by experiment that during the process of the alignment of the harvesting head to capture the trunk, the operator needs a lot of observation, judgment and repeated operations, which lead to the time and fuel losses. In order to improve the operation efficiency and reduce the operating costs, the point clouds for standing trees are collected with a low-cost 2D laser scanner. A cluster extracting algorithm and filtering algorithm are used to classify each trunk from the point cloud. On the assumption that every cross section of the target trunk is approximate a standard circle and combining the information of an Attitude and Heading Reference System, the radii and center locations of the trunks in the scanning range are calculated by the Fletcher-Reeves conjugate gradient algorithm. The method is validated through experiments in an aspen forest, and the optimized calculation time consumption is compared with the previous work of other researchers. Moreover, the implementation of the calculation result for automotive capturing trunks by the harvesting head during the logging operation is discussed in particular. PMID:23012543

  4. Shining new light on braided rivers: capturing grain-to-reach scale morphodynamics with terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Brasington, J.; Williams, R. D.; Vericat, D.; Hicks, M.; Goodsell, B.

    2011-12-01

    The last decade has witnessed a technological revolution in the acquisition of geospatial data. These developments have profound implications for the practice of river science, creating a step-change in the dimensionality, resolution and precision of measurement of fluvial forms and processes. The pace of change has been remarkable; typical datasets of channel geometry have grown from cross-sections containing a few hundred survey observations, to airborne lidar surveys incorporating millions of points. With wide-area terrestrial laser scans comprising tens of billions observations now set to emerge, our data perspectives have been expanded by seven orders of magnitude. Such rapid modernization brings with it new challenges and necessitates the development of novel data management strategies, original algorithms to process dense 3d data, higher dimensional spatial metrics and innovative simulation methods to make optimal use of this rich vein of information. In this paper we describe a field-to-product methodology which aims to address these challenges and has been used to generate an unparalleled dataset capturing the morphological evolution of a labile gravel-bed braided river through a continuous sequence of floods between Oct 2009 and May 2010. These data were generated using a data-fusion approach that combines close-range terrestrial laser scanning with bathymetric data derived from non-metric aerial photography. Surveys were acquired over a 2.5 x 0.7 km reach of the Rees River; a piedmont braided system draining a highland catchment of Southern Alps of NZ. During a 10 month field campaign through the summer flood season, this study reach was resurveyed systematically after each competent flood event. Multi-scale DEMs were derived that capture the spatial distribution of facies and morphological changes at high precision. Results indicate that over 80% of the reach was subject to significant erosion or deposition, with a complex pattern of response to the

  5. Graph Structure-Based Simultaneous Localization and Mapping Using a Hybrid Method of 2D Laser Scan and Monocular Camera Image in Environments with Laser Scan Ambiguity

    PubMed Central

    Oh, Taekjun; Lee, Donghwa; Kim, Hyungjin; Myung, Hyun

    2015-01-01

    Localization is an essential issue for robot navigation, allowing the robot to perform tasks autonomously. However, in environments with laser scan ambiguity, such as long corridors, the conventional SLAM (simultaneous localization and mapping) algorithms exploiting a laser scanner may not estimate the robot pose robustly. To resolve this problem, we propose a novel localization approach based on a hybrid method incorporating a 2D laser scanner and a monocular camera in the framework of a graph structure-based SLAM. 3D coordinates of image feature points are acquired through the hybrid method, with the assumption that the wall is normal to the ground and vertically flat. However, this assumption can be relieved, because the subsequent feature matching process rejects the outliers on an inclined or non-flat wall. Through graph optimization with constraints generated by the hybrid method, the final robot pose is estimated. To verify the effectiveness of the proposed method, real experiments were conducted in an indoor environment with a long corridor. The experimental results were compared with those of the conventional GMappingapproach. The results demonstrate that it is possible to localize the robot in environments with laser scan ambiguity in real time, and the performance of the proposed method is superior to that of the conventional approach. PMID:26151203

  6. Graph Structure-Based Simultaneous Localization and Mapping Using a Hybrid Method of 2D Laser Scan and Monocular Camera Image in Environments with Laser Scan Ambiguity.

    PubMed

    Oh, Taekjun; Lee, Donghwa; Kim, Hyungjin; Myung, Hyun

    2015-01-01

    Localization is an essential issue for robot navigation, allowing the robot to perform tasks autonomously. However, in environments with laser scan ambiguity, such as long corridors, the conventional SLAM (simultaneous localization and mapping) algorithms exploiting a laser scanner may not estimate the robot pose robustly. To resolve this problem, we propose a novel localization approach based on a hybrid method incorporating a 2D laser scanner and a monocular camera in the framework of a graph structure-based SLAM. 3D coordinates of image feature points are acquired through the hybrid method, with the assumption that the wall is normal to the ground and vertically flat. However, this assumption can be relieved, because the subsequent feature matching process rejects the outliers on an inclined or non-flat wall. Through graph optimization with constraints generated by the hybrid method, the final robot pose is estimated. To verify the effectiveness of the proposed method, real experiments were conducted in an indoor environment with a long corridor. The experimental results were compared with those of the conventional GMappingapproach. The results demonstrate that it is possible to localize the robot in environments with laser scan ambiguity in real time, and the performance of the proposed method is superior to that of the conventional approach. PMID:26151203

  7. Laser-scanning tomography and related dark-field nanoscopy method

    NASA Astrophysics Data System (ADS)

    Montgomery, Paul C.; Gall-Borrut, Pascal; Ardisasmita, Syamsa M.; Castagne, Michel; Bonnafe, Jacques; Fillard, Jean-Pierre

    1991-01-01

    Nanoscopy is a term that we use to describe optical techniques using digital image processing that are capable of nanometric observation and measurement. Laser Scanning Tomography (LST) is used for defect analysis in the bulk of semiconductor wafers for revealing particles as small as mm and for measuring densities of uptolO13 cm3 The unusually high contrast of the system allows us to observe submicron particles which are more than three orders of magnitude smaller than the Rayleigh criterion for the optical system. Recent work using deconvolution of point image functions enables us to perform sub-micron optical serial sectioning, for determining the depth of defects. The best conditions for classical LST (using laser illumination perpendicular to the viewing direction) are when operating further than a few microns below the surface in semiconductor wafers; ie it is ideal for bulk defect studies. The study of imperfections inside epilayers in the top ijim layer requires a modified technique. Instead of illuminating at 900 the viewing direction, the infra red laser beam is introduced obliquely to the front suffe to illuminate the defects in the epilayer while still in the dark-field mode. Combining this method with high resolution sectioning will be the basis for a technique of three dimensional submicron defect analysis in epilayers. Results are given of defect studies in annealed GaAs and silicon to demonstrate the capabilities of LST for naiiometer analysis in bulk materials. Sub-micron depth measurement is shown for single particles using the PSF of the system for the out-offocus case. Some initial results are given of studies of defects in a highly lattice mismatched epilayer using IR transmission microscopy, phase stepping microscopy (PSM, used in surface profiling) and the new dark field oblique laser illumination technique. LST, and the new nanoscopy techniques are non-destructive, operate under normal room conditions, and give sub-micron observation and

  8. Embedding complementary imaging data in laser scanning microscopy micrographs by reversible watermarking

    PubMed Central

    Dragoi, Ioan-Catalin; Stanciu, Stefan G.; Hristu, Radu; Coanda, Henri-George; Tranca, Denis E.; Popescu, Marius; Coltuc, Dinu

    2016-01-01

    Complementary laser scanning microscopy micrographs are considered as pairs consisting in a master image (MI) and a slave image (SI), the latter with potential for facilitating the interpretation of the MI. We propose a strategy based on reversible watermarking for embedding a lossy compressed version of the SI into the MI. The use of reversible watermarking ensures the exact recovery of the host image. By storing and/or transmitting the watermarked MI in a single file, the information contained in both images that constitute the pair is made available to a potential end-user, which simplifies data association and transfer. Examples are presented using support images collected by two complementary techniques, confocal scanning laser microscopy and transmission laser scanning microscopy, on Hematoxylin and Eosin stained tissue fragments. A strategy for minimizing the watermarking distortions of the MI, while preserving the content of the SI, is discussed in detail.

  9. Detection of Gold Nanoparticles Aggregation Growth Induced by Nucleic Acid through Laser Scanning Confocal Microscopy

    PubMed Central

    Gary, Ramla; Carbone, Giovani; Petriashvili, Gia; De Santo, Maria Penelope; Barberi, Riccardo

    2016-01-01

    The gold nanoparticle (GNP) aggregation growth induced by deoxyribonucleic acid (DNA) is studied by laser scanning confocal and environmental scanning electron microscopies. As in the investigated case the direct light scattering analysis is not suitable, we observe the behavior of the fluorescence produced by a dye and we detect the aggregation by the shift and the broadening of the fluorescence peak. Results of laser scanning confocal microscopy images and the fluorescence emission spectra from lambda scan mode suggest, in fact, that the intruding of the hydrophobic moiety of the probe within the cationic surfactants bilayer film coating GNPs results in a Förster resonance energy transfer. The environmental scanning electron microscopy images show that DNA molecules act as template to assemble GNPs into three-dimensional structures which are reminiscent of the DNA helix. This study is useful to design better nanobiotechnological devices using GNPs and DNA. PMID:26907286

  10. Designing a laser scanning picoprojector. Part 2: laser-safety-related issues.

    PubMed

    Wallhead, Ian; Ocaña, Roberto; Quinzá, Paula

    2012-08-10

    Laser scanning picoprojectors present a new challenge in the field of laser safety with methods of calculating accessible emission limits still in their infancy. We present a laser safety analysis and a calculation of an example picoprojector. We show that, due to its scanning operation, a picoprojector should be considered an extended laser source, and we also show that a picoprojector with two separate one-axis microelectromechanical systems mirrors offers a higher safe power limit than a projector with a single scanning mirror. Finally, a safety analysis is done under conditions of mirror failure. We show that, if the projector fails to scan in just one of the axes, the ocular hazard rises sharply, highlighting the need for a fail-safe system to be built into laser scanning picoprojectors. PMID:22885573

  11. Embedding complementary imaging data in laser scanning microscopy micrographs by reversible watermarking.

    PubMed

    Dragoi, Ioan-Catalin; Stanciu, Stefan G; Hristu, Radu; Coanda, Henri-George; Tranca, Denis E; Popescu, Marius; Coltuc, Dinu

    2016-04-01

    Complementary laser scanning microscopy micrographs are considered as pairs consisting in a master image (MI) and a slave image (SI), the latter with potential for facilitating the interpretation of the MI. We propose a strategy based on reversible watermarking for embedding a lossy compressed version of the SI into the MI. The use of reversible watermarking ensures the exact recovery of the host image. By storing and/or transmitting the watermarked MI in a single file, the information contained in both images that constitute the pair is made available to a potential end-user, which simplifies data association and transfer. Examples are presented using support images collected by two complementary techniques, confocal scanning laser microscopy and transmission laser scanning microscopy, on Hematoxylin and Eosin stained tissue fragments. A strategy for minimizing the watermarking distortions of the MI, while preserving the content of the SI, is discussed in detail. PMID:27446641

  12. Detection of Gold Nanoparticles Aggregation Growth Induced by Nucleic Acid through Laser Scanning Confocal Microscopy.

    PubMed

    Gary, Ramla; Carbone, Giovani; Petriashvili, Gia; De Santo, Maria Penelope; Barberi, Riccardo

    2016-01-01

    The gold nanoparticle (GNP) aggregation growth induced by deoxyribonucleic acid (DNA) is studied by laser scanning confocal and environmental scanning electron microscopies. As in the investigated case the direct light scattering analysis is not suitable, we observe the behavior of the fluorescence produced by a dye and we detect the aggregation by the shift and the broadening of the fluorescence peak. Results of laser scanning confocal microscopy images and the fluorescence emission spectra from lambda scan mode suggest, in fact, that the intruding of the hydrophobic moiety of the probe within the cationic surfactants bilayer film coating GNPs results in a Förster resonance energy transfer. The environmental scanning electron microscopy images show that DNA molecules act as template to assemble GNPs into three-dimensional structures which are reminiscent of the DNA helix. This study is useful to design better nanobiotechnological devices using GNPs and DNA. PMID:26907286

  13. Revisit laser scanning fluorescence microscopy performance under fluorescence-lifetime-limited regime

    NASA Astrophysics Data System (ADS)

    Chan, Antony C.; Wong, Terence T. W.; Wong, Kenneth K. Y.; Lam, Edmund Y.; Tsia, Kevin K.

    2014-03-01

    Continuing desire for higher-speed laser scanning fluorescence microscopy (LSFM) and progressive advancement in ultrafast and sensitive photodetectors might imply that our conventional understanding of LSFM is not adequate when approaching to the intrinsic speed limit — fluorescence lifetime. In this regard, we here revisit the theoretical framework of LSFM and evaluate its general performance in lifetime-limited and noise-limited regimes. Our model suggests that there still exists an order-of-magnitude gap between the current LSFM speed and the intrinsic limit. An imaging frame rate of > 100 kHz could be viable with the emerging laser-scanning techniques using ultrafast wavelength-swept sources, or optical time-stretch.

  14. Standalone Terrestrial Laser Scanning for Efficiently Capturing Aec Buildings for As-Built Bim

    NASA Astrophysics Data System (ADS)

    Bassier, M.; Vergauwen, M.; Van Genechten, B.

    2016-06-01

    With the increasing popularity of as-built building models for the architectural, engineering and construction (AEC) industry, the demand for highly accurate and dense point cloud data is rising. The current data acquisition methods are labour intensive and time consuming. In order to compete with indoor mobile mapping systems (IMMS), surveyors are now opting to use terrestrial laser scanning as a standalone solution. However, there is uncertainty about the accuracy of this approach. The emphasis of this paper is to determine the scope for which terrestrial laser scanners can be used without additional control. Multiple real life test cases are evaluated in order to identify the boundaries of this technique. Furthermore, this research presents a mathematical prediction model that provides an indication of the data accuracy given the project dimensions. This will enable surveyors to make informed discussions about the employability of terrestrial laser scanning without additional control in mid to large-scale projects.

  15. 100 kHz Mueller polarimeter for laser scanning polarimetric microscopy

    NASA Astrophysics Data System (ADS)

    Le Gratiet, A.; Dubreuil, M.; Rivet, S.; Le Grand, Y.

    2016-04-01

    A new setup was recently proposed to perform Mueller matrix polarimetry at 100 kHz using a swept laser source, high order retarders and a single channel photodetector. In this communication, we present the implementation of this setup on a laser scanning microscope to perform high speed scanning Mueller microscopy in transmission. Calibration of the instrument is briefly described and precision and stability over time are evaluated. Finally, Mueller images of a manufactured scene are reported. To our best knowledge, this is the first time that Mueller polarimetry is performed using a laser scanning microscope. We further plan to develop confocal/nonlinear/Mueller microscopy from the same setup in order to produce multimodal contrast images of biological samples.

  16. An entropy-based filtering approach for airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Zeng, Zhe; Wan, Jiaxin; Liu, Hui

    2016-03-01

    Parameter-tuning is a challenging task when generating digital terrain models from airborne laser scanning (light detection and ranging, LiDAR) data. To address this issue, this paper presents a filtering method for near-infrared laser scanning data that exploits the principle of entropy maximization as the optimization objective. The proposed approach generates ground elevation of point cloud by constructing a triangulated irregular network, calculates the entropy of the elevation from different parts, and automatically separates ground and non-ground points by the principle of entropy maximization. Experimental results from different ground surfaces show that the proposed entropy-based filtering method can effectively extract bare-earth points from the point cloud without adjusting thresholds.

  17. An Automatic Algorithm for Minimizing Anomalies and Discrepancies in Point Clouds Acquired by Laser Scanning Technique

    NASA Astrophysics Data System (ADS)

    Bordin, Fabiane; Gonzaga, Luiz, Jr.; Galhardo Muller, Fabricio; Veronez, Mauricio Roberto; Scaioni, Marco

    2016-06-01

    Laser scanning technique from airborne and land platforms has been largely used for collecting 3D data in large volumes in the field of geosciences. Furthermore, the laser pulse intensity has been widely exploited to analyze and classify rocks and biomass, and for carbon storage estimation. In general, a laser beam is emitted, collides with targets and only a percentage of emitted beam returns according to intrinsic properties of each target. Also, due interferences and partial collisions, the laser return intensity can be incorrect, introducing serious errors in classification and/or estimation processes. To address this problem and avoid misclassification and estimation errors, we have proposed a new algorithm to correct return intensity for laser scanning sensors. Different case studies have been used to evaluate and validated proposed approach.

  18. UNDERSTANDING THE EFFECTS OF SURFACTANT ADDITION ON RHEOLOGY USING LASER SCANNING CONFOCAL MICROSCOPY

    SciTech Connect

    White, T

    2007-05-08

    The effectiveness of three dispersants to modify rheology was examined using rheology measurements and laser scanning confocal microscopy (LSCM) in simulated waste solutions. All of the dispersants lowered the yield stress of the slurries below the baseline samples. The rheology curves were fitted reasonably to a Bingham Plastic model. The three-dimensional LSCM images of simulants showed distinct aggregates were greatly reduced after the addition of dispersants leading to a lowering of the yield stress of the simulated waste slurry solutions.

  19. Three-dimensional imaging of monogenoidean sclerites by laser scanning confocal fluorescence microscopy.

    PubMed

    Galli, Paolo; Strona, Giovanni; Villa, Anna Maria; Benzoni, Francesca; Fabrizio, Stefani; Doglia, Silvia Maria; Kritsky, Delane C

    2006-04-01

    A nondestructive protocol for preparing specimens of Monogenoidea for both alpha-taxonomic studies and reconstruction of 3-dimensional structure is presented. Gomori's trichrome, a stain commonly used to prepare whole-mount specimens of monogenoids for taxonomic purposes, is used to provide fluorescence of genital spines, the copulatory organ, accessory piece, squamodisc, anchors, hooks, bars, and clamps under laser scanning confocal microscopy. PMID:16729702

  20. An automated method to register airborne and terrestrial laser scanning point clouds

    NASA Astrophysics Data System (ADS)

    Yang, Bisheng; Zang, Yufu; Dong, Zhen; Huang, Ronggang

    2015-11-01

    Laser scanning techniques have been widely used to capture three-dimensional (3D) point clouds of various scenes (e.g. urban scenes). In particular, airborne laser scanning (ALS) and mobile laser scanning (MLS), terrestrial laser scanning (TLS) are effective to capture point clouds from top or side view. Registering the complimentary point clouds captured by ALS and MLS/TLS provides an aligned data source for many purposes (e.g. 3D reconstruction). Among these MLS can be directly geo-referenced to ALS according to the equipped position systems. For small scanning areas or dense building areas, TLS is used instead of MLS. However, registering ALS and TLS datasets suffers from poor automation and robustness because of few overlapping areas and sparse corresponding geometric features. A robust method for the registration of TLS and ALS datasets is proposed, which has four key steps. (1) extracts building outlines from TLS and ALS data sets independently; (2) obtains the potential matching pairs of outlines according to the geometric constraints between building outlines; (3) constructs the Laplacian matrices of the extracted building outlines to model the topology between the geometric features; (4) calculates the correlation coefficients of the extracted geometric features by decomposing the Laplacian matrices into the spectral space, providing correspondences between the extracted features for coarse registration. Finally, the multi-line adjustment strategy is employed for the fine registration. The robustness and accuracy of the proposed method are verified using field data, demonstrating a reliable and stable solution to accurately register ALS and TLS datasets.

  1. SAR Satellite Images and Terrestrial Laser Scanning in Forest Damages Mapping in Finland

    NASA Astrophysics Data System (ADS)

    Karjalainen, Mika; Kaasalainen, Sanna; Hyyppa, Juha; Holopainen, Markus; Lyytikainen-Saarenmaa, Paivi; Krooks, Anssi; Jaakkola, Anttoni

    2010-12-01

    Forests are of high importance for the Finnish economy and environment. Forests inventories should not only provide information about the volume of growing stock, but also about the health status of forests, which is an indicator of the annual growth of forests and Carbon balance. One of the forest damage types is defoliation, which causes forest growth reduction and consequently potentially economical losses to the forest owners, but can be seen as an environmental indicator also. For example, in the past ten years, extensive and persistent needle defoliation caused by insects has been observed in the areas of Palokangas and Outokumpu in Eastern Finland. It is expected that the insect outbreaks are becoming more common and new species of insects may be spreading out in Finland due to the climate warming. Traditionally the intensity of needle defoliation has been estimated using visual observations, which are prone to errors and their areal extent is limited. Therefore, remote sensing can be seen as a potential tool for mapping defoliation. In this study, both Terrestrial Laser Scanning data and SAR satellite images have been exploited. On the one hand, Terrestrial Laser Scanning provides means to rapidly and objectively measure critical forest related information. On the other hand, SAR satellite images enable wide-area mapping and constant monitoring, which would be impossible in Finland using optical satellite images due to the cloudiness. The fusion of Laser scanning and SAR information could make a difference in forest health mapping. In this paper, preliminary results of the estimation of the needle defoliation intensity based on Terrestrial Laser Scanning and ERS and Envisat SAR (non-interferometric) satellite data are presented.

  2. Atomic force microscopy and confocal laser scanning microscopy on the cytoskeleton of permeabilised and embedded cells.

    PubMed

    Meller, Karl; Theiss, Carsten

    2006-03-01

    We describe a technical method of cell permeabilisation and embedding to study the organisation and distribution of intracellular proteins with aid of atomic force microscopy and confocal laser scanning microscopy in identical areas. While confocal laser scanning microscopy is useful for the identification of certain proteins subsequent labelling with markers or antibodies, atomic force microscopy allows the observation of macromolecular structures in fixed and living cells. To demonstrate the field of application of this preparatory technique, cells were permeabilised, fixed, and the actin cytoskeleton was stained with phalloidin-rhodamine. Confocal laser scanning microscopy was used to show the organisation of these microfilaments, e.g. geodesic dome structures. Thereafter, cells were embedded in Durcupan water-soluble resin, followed by UV-polymerisation of resin at 4 degrees C. This procedure allowed intracellular visualisation of the cell nucleus or cytoskeletal elements by atomic force microscopy, for instance to analyse the globular organisation of actin filaments. Therefore, this method offers a great potential to combine both microscopy techniques in order to understand and interpret intracellular protein relations, for example, the biochemical and morphological interaction of the cytoskeleton. PMID:16360280

  3. 3D laser scanning and modelling of the Dhow heritage for the Qatar National Museum

    NASA Astrophysics Data System (ADS)

    Wetherelt, A.; Cooper, J. P.; Zazzaro, C.

    2014-08-01

    Curating boats can be difficult. They are complex structures, often demanding to conserve whether in or out of the water; they are usually large, difficult to move on land, and demanding of gallery space. Communicating life on board to a visiting public in the terra firma context of a museum can be difficult. Boats in their native environment are inherently dynamic artifacts. In a museum they can be static and divorced from the maritime context that might inspire engagement. New technologies offer new approaches to these problems. 3D laser scanning and digital modeling offers museums a multifaceted means of recording, monitoring, studying and communicating watercraft in their care. In this paper we describe the application of 3D laser scanning and subsequent digital modeling. Laser scans were further developed using computer-generated imagery (CGI) modeling techniques to produce photorealistic 3D digital models for development into interactive, media-based museum displays. The scans were also used to generate 2D naval lines and orthographic drawings as a lasting curatorial record of the dhows held by the National Museum of Qatar.

  4. Automatic recognition of piping system from laser scanned point clouds using normal-based region growing

    NASA Astrophysics Data System (ADS)

    Kawashima, K.; Kanai, S.; Date, H.

    2013-10-01

    In recent years, renovations of plant equipment have been more frequent, and constructing 3D as-built models of existing plants from large-scale laser scanned data is expected to make rebuilding processes more efficient. However, laser scanned data consists of enormous number of points, captures tangled objects and includes a high noise level, so that the manual reconstruction of a 3D model is very time-consuming. Among plant equipment, piping systems especially account for the greatest proportion. Therefore, the purpose of this research was to propose an algorithm which can automatically recognize a piping system from large-scale laser scanned data of plants. The straight portion of pipes, connecting parts and connection relationship of the piping system can be automatically recognized. Normal-based region growing enables the extraction of points on the piping system. Eigen analysis of the normal tensor and cylinder surface fitting allows the algorithm to recognize portions of straight pipes. Tracing the axes of the piping system and interpolation of the axes can derive connecting parts and connection relationships between elements of the piping system. The algorithm was applied to large-scale scanned data of an oil rig and a chemical plant. The recognition rate of straight pipes, elbows, junctions achieved 93%, 88% and 87% respectively.

  5. Decision model in the laser scanning system for pavement crack detection

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoming; Huang, Jianping; Liu, Wanyu

    2011-12-01

    Pavement crack detection plays an important role in the pavement maintaining and management. Recently, the laser scanning technique for pavement crack detection becomes more and more popular due to its ability of discriminating dark areas, which are not caused by pavement distress such as tire marks, oil spills, and shadows. However, this technique still bears some errors for pavement crack recognition errors, thus in the present work, the factors contributed to these errors in laser scanning system are first analyzed, and then a decision model for the laser scanning pavement crack detection system based on the hypothesis test is proposed. Experimental analyses and results show that this model not only allows us to build the relationship between the contribution factors and crack detection accuracy and to provide the criteria to compare the detection accuracy for the different roads, but also can be used to judge whether the crack exists with a reasonable number of deformed light stripes. Therefore, the proposed decision model can provide guidance on the pavement crack detection and has a practical value.

  6. Roof Modelling Potential of Unmanned Air Vehicle Point Clouds with Respect to Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Karakis, Serkan; Gunes Sefercik, Umut; Atalay, Can

    2016-07-01

    In parallel with the improvement of laser scanning technologies, dense point clouds which provide the detailed description of terrain and non-terrain objects became indispensable for remotely-sensed data users. Owing to the large demand, besides laser scanning, point clouds were started to achieve using photogrammetric images. Unmanned air vehicle (UAV) images are one of the most preferred data for creating dense point clouds by the advantage of low cost, rapid and periodically gain. In this study, we tried to assess the roof modelling potential of UAV point clouds by comparing three dimensional (3D) roof models produced from UAV and terrestrial laser scanning (TLS) point clouds. In the study, very popular low cost action camera SJ4000 and Faro Laser Scanner Focus3D X 330 were used to provide point clouds and the roof of Bulent Ecevit University Civil Aviation Academy building was utilized. For the validation of horizontal and vertical geolocation accuracies, standard deviation was used as the main indicator. The visual results demonstrated that UAV roof model is almost coherent with TLS roof model after the filtering-based refinement on noisy pixels and systematic bias correction. Moreover, the horizontal geolocation accuracy is approx. |5cm| both in X and Y directions and bias corrected vertical geolocation accuracy is approx. 17cm for zero roof slope.

  7. Multiparameter Correction Intensity of Terrestrial Laser Scanning Data as AN Input for Rock Surface Modelling

    NASA Astrophysics Data System (ADS)

    Paleček, V.; Kubíček, P.

    2016-06-01

    A large increase in the creation of 3D models of objects all around us can be observed in the last few years; thanks to the help of the rapid development of new advanced technologies for spatial data collection and robust software tools. A new commercially available airborne laser scanning data in Czech Republic, provided in the form of the Digital terrain model of the fifth generation as irregularly spaced points, enable locating the majority of rock formations. However, the positional and height accuracy of this type of landforms can reach huge errors in some cases. Therefore, it is necessary to start mapping using terrestrial laser scanning with the possibility of adding a point cloud data derived from ground or aerial photogrammetry. Intensity correction and noise removal is usually based on the distance between measured objects and the laser scanner, the incidence angle of the beam or on the radiometric and topographic characteristics of measured objects. This contribution represents the major undesirable effects that affect the quality of acquisition and processing of laser scanning data. Likewise there is introduced solutions to some of these problems.

  8. Comparison of 3d Reconstruction Services and Terrestrial Laser Scanning for Cultural Heritage Documentation

    NASA Astrophysics Data System (ADS)

    Rasztovits, S.; Dorninger, P.

    2013-07-01

    Terrestrial Laser Scanning (TLS) is an established method to reconstruct the geometrical surface of given objects. Current systems allow for fast and efficient determination of 3D models with high accuracy and richness in detail. Alternatively, 3D reconstruction services are using images to reconstruct the surface of an object. While the instrumental expenses for laser scanning systems are high, upcoming free software services as well as open source software packages enable the generation of 3D models using digital consumer cameras. In addition, processing TLS data still requires an experienced user while recent web-services operate completely automatically. An indisputable advantage of image based 3D modeling is its implicit capability for model texturing. However, the achievable accuracy and resolution of the 3D models is lower than those of laser scanning data. Within this contribution, we investigate the results of automated web-services for image based 3D model generation with respect to a TLS reference model. For this, a copper sculpture was acquired using a laser scanner and using image series of different digital cameras. Two different webservices, namely Arc3D and AutoDesk 123D Catch were used to process the image data. The geometric accuracy was compared for the entire model and for some highly structured details. The results are presented and interpreted based on difference models. Finally, an economical comparison of the generation of the models is given considering the interactive and processing time costs.

  9. Terrestrial laser scanning to model sunlight irradiance on cadavers under conditions of natural decomposition.

    PubMed

    Bucheli, Sibyl Rae; Pan, Zhigang; Glennie, Craig L; Lynne, Aaron M; Haarman, Daniel P; Hill, John M

    2014-07-01

    Human decomposition is a dynamic process that is influenced by both abiotic and biotic factors. Measuring these influences, in particular abiotic factors, on the decomposition process is often a challenge for scientists. Recently, researchers have turned to the use of advanced remote sensing technologies in forensic investigations. In this study, a new methodology is described that utilizes precise 3D images captured using terrestrial laser scanning (TLS) to calculate total solar irradiance on a cadaver in a partially forested environment. To test this new measurement approach under actual field conditions, three cadavers were placed in an outdoor environment to decompose. Laser scans were taken the day of placement and used to calculate the total solar irradiance at time points of 24 h, 1 week, and 1 month from placement. The results show that as time progresses, different cadavers at the field site and different areas of the same cadaver receive varying amounts of solar irradiance. The modeling based on these laser scans can be used to create predictive images of solar irradiance that may provide researchers with a new tool to help quantitatively assess the effect of solar irradiance on a cadaver ecosystem. PMID:24806951

  10. Terrestrial Laser Scanning for Measuring Stream Bank Erosion within Legacy Sediments: Data Processing and Analysis Methods

    NASA Astrophysics Data System (ADS)

    Starek, M. J.; Mitasova, H.; Wegmann, K. W.

    2011-12-01

    Land clearing for agricultural purposes following European settlement of America resulted in upland erosion rates 50-400 times above long-term geologic rates in much of the North Carolina Piedmont region. A considerable amount of the eroded sediment was subsequently aggraded on floodplains and impounded in the slackwater ponds behind milldams. This trapped "legacy" sediment is commonly mistaken for natural floodplain deposition and has remained largely unrecognized as a potential source of accelerated sediment erosion contributing to modern water quality impairment. In this study, terrestrial laser scanning (TLS) is utilized to monitor stream bank evolution along a reach that has breached a former millpond. Due to the unique surface geometry and orientation of the stream bank, vegetation occlusion, and true 3D structure of the point cloud, a systematic data processing approach is implemented to compute the change in sediment volume between repeat TLS surveys. The processing approach consists of the following four steps: 1) segmentation of the stream bank point cloud; 2) transformation of the point cloud such that the xy plane is parallel to the trend of the bank; 3) filter vegetation by selecting local lowest point within a grid cell; 4) smooth high frequency noise 5) generate bare earth digital elevation model (DEM). From the DEMs, change in volume was quantified for a 13 m x 3.5 m section of the stream bank providing an estimate on erosion rates and slumping between surveys. The major mechanisms for the observed changes are freeze-thaw events and fluvial entrainment. To evaluate the surface evolution between the distinct sedimentary layers (legacy vs non-legacy) that comprise the stream bank, elevation change is modeled as a continuous trivariate function z = f(x,y,t) where x,y is horizontal location, t is time, and z is a first-surface referenced elevation. Hence, z=0 for all x,y at t=0, time of first survey. The filtered, transformed, and first

  11. Laser scanning methods and a phase comparison, modulated laser range finder for terrain sensing on a Mars roving vehicle. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Herb, G. T.

    1973-01-01

    Two areas of a laser range finder for a Mars roving vehicle are investigated: (1) laser scanning systems, and (2) range finder methods and implementation. Several ways of rapidly scanning a laser are studied. Two digital deflectors and a matrix of laser diodes, are found to be acceptable. A complete range finder scanning system of high accuracy is proposed. The problem of incident laser spot distortion on the terrain is discussed. The instrumentation for a phase comparison, modulated laser range finder is developed and sections of it are tested.

  12. Combining laser scan and photogrammetry for 3D object modeling using a single digital camera

    NASA Astrophysics Data System (ADS)

    Xiong, Hanwei; Zhang, Hong; Zhang, Xiangwei

    2009-07-01

    In the fields of industrial design, artistic design and heritage conservation, physical objects are usually digitalized by reverse engineering through some 3D scanning methods. Laser scan and photogrammetry are two main methods to be used. For laser scan, a video camera and a laser source are necessary, and for photogrammetry, a digital still camera with high resolution pixels is indispensable. In some 3D modeling tasks, two methods are often integrated to get satisfactory results. Although many research works have been done on how to combine the results of the two methods, no work has been reported to design an integrated device at low cost. In this paper, a new 3D scan system combining laser scan and photogrammetry using a single consumer digital camera is proposed. Nowadays there are many consumer digital cameras, such as Canon EOS 5D Mark II, they usually have features of more than 10M pixels still photo recording and full 1080p HD movie recording, so a integrated scan system can be designed using such a camera. A square plate glued with coded marks is used to place the 3d objects, and two straight wood rulers also glued with coded marks can be laid on the plate freely. In the photogrammetry module, the coded marks on the plate make up a world coordinate and can be used as control network to calibrate the camera, and the planes of two rulers can also be determined. The feature points of the object and the rough volume representation from the silhouettes can be obtained in this module. In the laser scan module, a hand-held line laser is used to scan the object, and the two straight rulers are used as reference planes to determine the position of the laser. The laser scan results in dense points cloud which can be aligned together automatically through calibrated camera parameters. The final complete digital model is obtained through a new a patchwise energy functional method by fusion of the feature points, rough volume and the dense points cloud. The design

  13. High resolution scanning photoluminescence characterization of semi-insulating GaAs using a laser scanning microscope

    NASA Astrophysics Data System (ADS)

    Marek, J.; Elliot, A. G.; Wilke, V.; Geiss, R.

    1986-12-01

    Spatially resolved photoluminescence properties of semi-insulating, liquid encapsulated Czochralski-grown GaAs substrates are analyzed with a laser scanning microscope. The improved resolution of the laser scanning microscope results in the observation of single dislocations within the subgrain boundaries of the polyganized dislocation cell network for the first time by photoluminescence. Both the cell structure and the Cottrell cloud are clearly resolved.

  14. Terrestrial laser scanning for high resolution cyclostratigraphy of chert in pelagic limestone series

    NASA Astrophysics Data System (ADS)

    Penasa, L.; Franceschi, M.; Preto, N.

    2012-04-01

    We here propose the use of terrestrial laser scanning (TLS) for the mapping of chert on natural outcrops and for rapid extraction of its distribution along stratigraphic sections. The technique permits rapid production of high-definition time series for cyclostratigraphic analysis. Chert, sometimes referred to as flint, is a widespread component of sedimentary successions. It is often found in deep water and pelagic sediments and is constituted by cryptocrystalline varieties of quartz. It is generally accepted that the origin of chert is principally biogenic; it derives from the slow alteration, through a process called maturation, of opaline organic components as tests and spicules under the influence of pore waters. Most often, chert forms nodules of various size, or more or less continuous layers. Its color shows strong variability (white, red, gray, black). Although it could record paleoceanographic and climatic changes because of its biogenic nature, the cyclostratigraphic study of chert is largely neglected. This is mainly due to the difficulty of logging it. Hand logging is time consuming, but also, because of nodules' highly variable shape, lateral variability of chert abundance is large. Photographic image-processing techniques could help in principle, but they become difficult to use when chert has a color similar to that of the host rock. Chert is easily detectable in TLS generated images because of its very low reflectivity at infrared (IR) wavelengths, also where the color of chert in visible light is close to that of the host rock. Thus, TLS data can be used to map the distribution of chert on an outcrop, and to compute its abundance along a stratigraphic section. The ultimate result of such data processing, for which a suite of original procedures was implemented, is a stratigraphic log that is suitable for time series analysis. A section in the early Cretaceous Maiolica Formation of Central Italy (Gubbio) was considered as preliminary case study for

  15. CdSe/CdS-quantum rods: fluorescent probes for in vivo two-photon laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Dimitrijevic, Jelena; Krapf, Lisa; Wolter, Christopher; Schmidtke, Christian; Merkl, Jan-Philip; Jochum, Tobias; Kornowski, Andreas; Schüth, Anna; Gebert, Andreas; Hüttmann, Gereon; Vossmeyer, Tobias; Weller, Horst

    2014-08-01

    CdSe/CdS-Quantum-dots-quantum-rods (QDQRs) with an aspect ratio of ~6 are prepared via the seeded growth method, encapsulated within a shell of crosslinked poly(isoprene)-block-poly(ethylene glycol) (PI-b-PEG) diblock copolymer, and transferred from the organic phase into aqueous media. Their photoluminescence quantum yield (PLQY) of 78% is not compromised by the phase transfer. Within a period of two months the PLQY of QDQRs in aqueous solution at neutral pH decreases only slightly (to ~65%). The two-photon (TP) action cross sections of QDQRs (~105 GM) are two orders of magnitude higher than those of CdSe/CdS/ZnS-core/shell/shell quantum dots (QDs, ~103 GM) with comparable diameter (~5 nm). After applying PI-b-PEG encapsulated QDQRs onto the small intestinal mucosa of mice in vivo, their strong red fluorescence can easily be observed by two-photon laser scanning microscopy (TPLSM) and clearly distinguished from autofluorescent background. Our results demonstrate that PI-b-PEG encapsulated CdSe/CdS-QDQRs are excellent probes for studying the uptake and fate of nanoparticles by two-photon imaging techniques in vivo.CdSe/CdS-Quantum-dots-quantum-rods (QDQRs) with an aspect ratio of ~6 are prepared via the seeded growth method, encapsulated within a shell of crosslinked poly(isoprene)-block-poly(ethylene glycol) (PI-b-PEG) diblock copolymer, and transferred from the organic phase into aqueous media. Their photoluminescence quantum yield (PLQY) of 78% is not compromised by the phase transfer. Within a period of two months the PLQY of QDQRs in aqueous solution at neutral pH decreases only slightly (to ~65%). The two-photon (TP) action cross sections of QDQRs (~105 GM) are two orders of magnitude higher than those of CdSe/CdS/ZnS-core/shell/shell quantum dots (QDs, ~103 GM) with comparable diameter (~5 nm). After applying PI-b-PEG encapsulated QDQRs onto the small intestinal mucosa of mice in vivo, their strong red fluorescence can easily be observed by two-photon laser

  16. Improving peatland erosion rate measurements through the use of terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Grayson, R.; Holden, J.; Jones, R.; Lloyd, A.

    2013-12-01

    Globally peatlands account for 30-50% of all carbon stored within soils (Holden, 2005). Within the UK they represent the single largest terrestrial carbon store, with blanket bogs covering roughly 7.5% (Tallis et al., 1997); unfortunately these upland blanket bogs are often found in a degraded state. The amount of carbon being lost to erosional processes in peatlands is poorly constrained, with estimates typically being based on traditional low-tech methods. Erosion pins have been the primary method for measuring erosion rates in peatlands; however their use is prone to error due to the depth of peat and its high water content which allows both horizontal and vertical movement through time. Erosion pins can only realistically be used over a relatively small area and assume erosion remains constant between pins making any upscaling problematic. Therefore, innovative methods are required to improve estimates of peatland erosion that are capable of increasing both spatial coverage and accuracy. Terrestrial laser scanning is increasingly being used by geomorphologists to produce highly detailed 3D topographic maps. A pilot study was undertaken to assess the ability of terrestrial laser scanning to measure erosion rates within peatlands and to identify any obstacles that may need to be overcome. An actively eroding blanket bog in northern England was chosen as the test site with surveys being carried out before and after winter as active erosion is most likely during winter months. Erosion measurements were also made using erosion pins to allow comparisons between the two methods. Terrestrial laser scanning was not only found to offer vastly improved spatial coverage compared with erosion pins but was also able to provide data at a much higher resolution. Erosion rates calculated using erosion pins were significantly higher than the average rate calculated using terrestrial laser scanning (-35mm compared to +2.5mm), this overestimation by the erosion pins primarily

  17. Extraction of Forest Roads from Full-waveform Airborne Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Djuricic, Ana; Hollaus, Markus

    2013-04-01

    The knowledge about the position of forest roads is important for the management and protection of forests. Most often this information is not available on a digital form so that it can be integrated into a GIS to use it e.g. for routing applications or to plan harvesting activities. Furthermore, the available information about forest roads is often not up-to-date. The extraction of forest roads from remote sensing data i.e. aerial photographs is often limited due to the visibility of the terrain within a forest. The increasing availability of airborne laser scanning (ALS) data has changed this situation during the last years. As an active measurement system ALS provide geometric information from the forest floor as well as the forest canopy. Additionally, the new generation of ALS sensors, the so-called full-waveform sensors provide in addition to the geometric information (i.e. 3D position, echo width) radiometric information (i.e. backscatter cross section) about the backscattering objects, which are excellent data sources to describe the terrain surface within a forest. Thus the aim of this study is to develop a semi-automatic method to extract the position of forest roads from full-waveform ALS data. Based on the 3D point cloud different raster layers were derived such as the digital terrain model (DTM), the slope, the backscatter cross section, different roughness parameters (i.e. echo width, standard deviation of plane fitting residuals of terrain points), the vertical component of the surface normals and the normalized digital surface model (nDSM), which represents the object height above the natural ground. The developed workflow classifies each input raster separately into the classes roads and non-roads. Morphological operations were applied on the classified raster datasets to smooth the outline of the extracted roads and to remove any small gaps in the detected roads. Several raster outputs were combined and used further for additional GIS analysis and

  18. Image distortion and its correction in linear galvanometric mirrors-based laser-scanning microscopy

    NASA Astrophysics Data System (ADS)

    Wang, Wenbo; Wu, Zhenguo; Zeng, Haishan

    2015-05-01

    To simplify imaging focusing and calibration tasks, a laser-scanning microscope needs to scan at a moderate frame rate. The inertia of a galvanometric scanner leads to time delays when following external commands, which subsequently introduces image distortions that deteriorate as scan frequency increases. Sinusoidal and triangular waveforms were examined as fast axis driving patterns. The interplay among driving pattern, frequency, sampling rate, phase shift, linear scanning range, and their effect on reconstructed images was discussed. Utilizing position feedback from the linear galvo scanners, the effect of response time could be automatically compensated in real time. Precompensated triangular driving waveform offered the least amount of image distortion.

  19. Use of Terrestrial Laser Scanning Technology for Long Term High Precision Deformation Monitoring

    PubMed Central

    Vezočnik, Rok; Ambrožič, Tomaž; Sterle, Oskar; Bilban, Gregor; Pfeifer, Norbert; Stopar, Bojan

    2009-01-01

    The paper presents a new methodology for high precision monitoring of deformations with a long term perspective using terrestrial laser scanning technology. In order to solve the problem of a stable reference system and to assure the high quality of possible position changes of point clouds, scanning is integrated with two complementary surveying techniques, i.e., high quality static GNSS positioning and precise tacheometry. The case study object where the proposed methodology was tested is a high pressure underground pipeline situated in an area which is geologically unstable. PMID:22303152

  20. In vivo measurements of skin barrier: comparison of different methods and advantages of laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Patzelt, A.; Sterry, W.; Lademann, J.

    2010-12-01

    A major function of the skin is to provide a protective barrier at the interface between external environment and the organism. For skin barrier measurement, a multiplicity of methods is available. As standard methods, the determination of the transepidermal water loss (TEWL) as well as the measurement of the stratum corneum hydration, are widely accepted, although they offer some obvious disadvantages such as increased interference liability. Recently, new optical and spectroscopic methods have been introduced to investigate skin barrier properties in vivo. Especially, laser scanning microscopy has been shown to represent an excellent tool to study skin barrier integrity in many areas of relevance such as cosmetology, occupation, diseased skin, and wound healing.

  1. Imaging Single ZnO Vertical Nanowire Laser Cavities using UV-Laser Scanning Confocal Microscopy

    SciTech Connect

    Gargas, D.J.; Toimil-Molares, M.E.; Yang, P.

    2008-11-17

    We report the fabrication and optical characterization of individual ZnO vertical nanowire laser cavities. Dilute nanowire arrays with interwire spacing>10 ?m were produced by a modified chemical vapor transport (CVT) method yielding an ideal platform for single nanowire imaging and spectroscopy. Lasing characteristics of a single vertical nanowire are presented, as well as high-resolution photoluminescence imaging by UV-laser scanning confocal microscopy. In addition, three-dimensional (3D) mapping of the photoluminescence emission performed in both planar and vertical dimensions demonstrates height-selective imaging useful for vertical nanowires and heteronanostructures emerging in the field of optoelectronics and nanophotonics.

  2. An Adaptive-Tabu GA for Registration of CT and Surface Laser Scan.

    PubMed

    Lee, Jiann-Der; Huang, Jau-Hua; Huang, Chung-Hsien; Liu, Li-Chang

    2005-01-01

    An adaptive-tabu GA (Genetic Algorithm) method is proposed to improve some traditional GA methods in the registration of computer tomography (CT) and surface laser scan. In this method, the adaptive memory structure and search strategy of Tabu Search (TS) with the modified chromosome crossover and adaptive mutation are proposed to increase the convergence speed and accuracy of the fitness function. This registration method can be used on non-fiducial stereo-tactic brain surgeries to assist surgeons to diagnose and treat brain diseases. PMID:17280970

  3. Classification of Airborne Laser Scanning Data Using Geometric Multi-Scale Features and Different Neighbourhood Types

    NASA Astrophysics Data System (ADS)

    Blomley, R.; Jutzi, B.; Weinmann, M.

    2016-06-01

    In this paper, we address the classification of airborne laser scanning data. We present a novel methodology relying on the use of complementary types of geometric features extracted from multiple local neighbourhoods of different scale and type. To demonstrate the performance of our methodology, we present results of a detailed evaluation on a standard benchmark dataset and we show that the consideration of multi-scale, multi-type neighbourhoods as the basis for feature extraction leads to improved classification results in comparison to single-scale neighbourhoods as well as in comparison to multi-scale neighbourhoods of the same type.

  4. Use of the confocal laser scanning microscope in studies on the developmental biology of marine crustaceans.

    PubMed

    Buttino, Isabella; Ianora, Adrianna; Carotenuto, Ylenia; Zupo, Valerio; Miralto, Antonio

    2003-03-01

    Confocal Laser Scanning Microscope techniques have been applied to study the developmental biology of marine copepods and decapod larvae. The lipophylic probes DiI and DiOC(6) were used to study both the external and internal morphology of these crustaceans, whereas the same DiOC(6) and the specific nuclear probe Hoechst 33342 were used to study embryonic development of copepods in vivo. To distinguish viable from non-viable copepod embryos, the vital dye dichlorodihydrofluorescein diacetate (H(2)DCFDA) was used. Major advantages and difficulties in the use of these non-invasive techniques in studies of the reproductive biology of marine crustaceans are discussed. PMID:12567403

  5. Terrestrial Laser Scanning Cultural Heritage preservation in case of natural hazards

    NASA Astrophysics Data System (ADS)

    Kordic, B.; Medak, D.; Pribicevic, B.

    2009-04-01

    Croatian Adriatic coast and the City of Zagreb area are hazardous with respect to earthquake occurance. These areas are rich with cultural monuments, buildings, sculptures... Accurate 3D documentation is needed for reconstruction in case of damage caused by natural disasters like earthquake, landslide ,fire... The technology of terestrial laser scanning is a promising method for providing exact 3D models of cultural heritage. Meshes, point-clouds and models should be collected and constructed. Georeferenced models can be used for tourism as a basis for virtual worlds available both in the WWW or on DVD-s...

  6. Low temperature laser scanning microscopy of a superconducting radio-frequency cavity

    DOE PAGESBeta

    Ciovati, G.; Anlage, Steven M.; Baldwin, C.; Cheng, G.; Flood, R.; Jordan, K.; Kneisel, P.; Morrone, M.; Nemes, G.; Turlington, L.; et al

    2012-03-16

    An apparatus was created to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about one order of magnitude better than with earlier methods. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in details in this contribution.

  7. 3D laser scanning microscopy of hypervelocity impact features in metal and aerogel targets

    NASA Astrophysics Data System (ADS)

    Hillier, J. K.; Postberg, F.; Price, M. C.; Trieloff, M.; Li, Y. W.; Srama, R.

    2012-09-01

    We present the results of a study into the mapping of hypervelocity impact features using a Keyence VK-X200 3D laser scanning microscope. The impact features observed are impact craters in a variety of different metal targets (Al, Au and Cu) and impact tracks in aerogel targets, similar to those used in the Stardust mission. Differences in crater morphology between different target materials and impact velocities, as well as differences in track depth and diameter in aerogel, for particles of known constant dimensions, are discussed.

  8. Ti-6Al-4V electron beam weld qualification using laser scanning confocal microscopy

    SciTech Connect

    Wanjara, P. . E-mail: priti.wanjara@cnrc-nrc.gc.ca; Brochu, M.; Jahazi, M.

    2005-03-15

    Processing conditions for manufacturing Ti-6Al-4V components by welding using an electron beam source are known to influence the transformation microstructure in the narrow fusion and heat-affected zones of the weld region. This work examined the effect of multiple-sequence welding on the characteristics of the transformed beta microstructure, using laser scanning confocal microscopy to resolve the Widmanstaetten alpha-beta structure in the fusion zone. The evolution in the alpha interlamellar spacing and plate thickness with processing was then related to microhardness measurements in the weld region.

  9. Automatic Geo-Referencing Mobile Laser Scanning Data to Uav Images

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Huang, X.; Zhang, F.; Fu, Z.; Yang, C.

    2015-08-01

    In this paper, a framework for adjusting mobile laser scanning point cloud data to improve the accuracy is proposed by integrating high resolution UAV images and MLS. First, aerial triangulated images with a few high accuracy ground control points are taken as control information. Then, a hierarchical strategy is proposed for robust pairwise registration of feature points between point cloud and images, so as to find the deviation of the point cloud. In the next step, a shape-preserving piecewise cubic interpolating method is employed to fit the time dependent error model of the trajectory. Finally, experiments are given to prove the effectiveness of proposed framework.

  10. Voxel-Based Approach for Estimating Urban Tree Volume from Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Vonderach, C.; Voegtle, T.; Adler, P.

    2012-07-01

    The importance of single trees and the determination of related parameters has been recognized in recent years, e.g. for forest inventories or management. For urban areas an increasing interest in the data acquisition of trees can be observed concerning aspects like urban climate, CO2 balance, and environmental protection. Urban trees differ significantly from natural systems with regard to the site conditions (e.g. technogenic soils, contaminants, lower groundwater level, regular disturbance), climate (increased temperature, reduced humidity) and species composition and arrangement (habitus and health status) and therefore allometric relations cannot be transferred from natural sites to urban areas. To overcome this problem an extended approach was developed for a fast and non-destructive extraction of branch volume, DBH (diameter at breast height) and height of single trees from point clouds of terrestrial laser scanning (TLS). For data acquisition, the trees were scanned with highest scan resolution from several (up to five) positions located around the tree. The resulting point clouds (20 to 60 million points) are analysed with an algorithm based on voxel (volume elements) structure, leading to an appropriate data reduction. In a first step, two kinds of noise reduction are carried out: the elimination of isolated voxels as well as voxels with marginal point density. To obtain correct volume estimates, the voxels inside the stem and branches (interior voxels) where voxels contain no laser points must be regarded. For this filling process, an easy and robust approach was developed based on a layer-wise (horizontal layers of the voxel structure) intersection of four orthogonal viewing directions. However, this procedure also generates several erroneous "phantom" voxels, which have to be eliminated. For this purpose the previous approach was extended by a special region growing algorithm. In a final step the volume is determined layer-wise based on the extracted

  11. Semi-automated extraction and delineation of 3D roads of street scene from mobile laser scanning point clouds

    NASA Astrophysics Data System (ADS)

    Yang, Bisheng; Fang, Lina; Li, Jonathan

    2013-05-01

    Accurate 3D road information is important for applications such as road maintenance and virtual 3D modeling. Mobile laser scanning (MLS) is an efficient technique for capturing dense point clouds that can be used to construct detailed road models for large areas. This paper presents a method for extracting and delineating roads from large-scale MLS point clouds. The proposed method partitions MLS point clouds into a set of consecutive "scanning lines", which each consists of a road cross section. A moving window operator is used to filter out non-ground points line by line, and curb points are detected based on curb patterns. The detected curb points are tracked and refined so that they are both globally consistent and locally similar. To evaluate the validity of the proposed method, experiments were conducted using two types of street-scene point clouds captured by Optech's Lynx Mobile Mapper System. The completeness, correctness, and quality of the extracted roads are over 94.42%, 91.13%, and 91.3%, respectively, which proves the proposed method is a promising solution for extracting 3D roads from MLS point clouds.

  12. 3D Imaging of Porous Media Using Laser Scanning Confocal Microscopy with Application to Microscale Transport Processes

    SciTech Connect

    Fredrich, J.T.

    1999-02-10

    We present advances in the application of laser scanning confocal microscopy (LSCM) to image, reconstruct, and characterize statistically the microgeometry of porous geologic and engineering materials. We discuss technical and practical aspects of this imaging technique, including both its advantages and limitations. Confocal imaging can be used to optically section a material, with sub-micron resolution possible in the lateral and axial planes. The resultant volumetric image data, consisting of fluorescence intensities for typically {approximately}50 million voxels in XYZ space, can be used to reconstruct the three-dimensional structure of the two-phase medium. We present several examples of this application, including studying pore geometry in sandstone, characterizing brittle failure processes in low-porosity rock deformed under triaxial loading conditions in the laboratory, and analyzing the microstructure of porous ceramic insulations. We then describe approaches to extract statistical microgeometric descriptions from volumetric image data, and present results derived from confocal volumetric data sets. Finally, we develop the use of confocal image data to automatically generate a three-dimensional mesh for numerical pore-scale flow simulations.

  13. 3-D ice shape measurements using mid-infrared laser scanning.

    PubMed

    Gong, Xiaoliang; Bansmer, Stephan

    2015-02-23

    A general approach based on mid-infrared (MIR) laser scanning is proposed to measure the 3-D ice shape no matter whether the ice is composed of clear ice, rime ice, mixed ice, or even supercooled water droplets or films. This is possible because MIR radiation penetrates ice and water only within a depth of less than 10 micrometers. First, an MIR laser point scanning technique is implemented and verified on transparent glass and clear ice. Then, to improve efficiency, an MIR laser line scanning method is developed and validated on different models. At last, several sequential MIR laser line scans are applied to trace the 3-D shape evolution of the continuous ice accretion on an airfoil in an icing wind tunnel. The ice growth process can be well observed in the results. The MIR scan shows a good agreement with the traditional visible laser scan on a plastic replication of the final ice shape made by the mold and casting method. PMID:25836526

  14. Measuring calcium levels in Saprolegnia ferax using the two-photon laser scanning microscope

    NASA Astrophysics Data System (ADS)

    Lilje, Osu

    2003-07-01

    xThe genus Saprolegnia in the phylum Oomycetes contains a number of parasitic species that can cause a range of important animal diseases. The aim of this study was to measure the calcium gradient, one of the growth regulating mechanisms, in Saprolegnia ferax. The two-photon laser scanning microscope allowed for detailed physiological measurements of calcium levels along the fungus-like hyphae of S.ferax. Calcium concentration was determined by making ratiometric calculation of emission levels of the calcium-sensitive fluorochrome Indo-1 at 485nm to 405nm. The calculated values were compared to the intracellular calibration values. The advantage of the two-photon laser scanning microscope is that it allows minor changes in concentration to be detected in highly localized regions of the hyphae. The technique used in this study minimized background and autofluorescence and therefore allowed for more accurate changes in intracellular Ca2+ concentration to be detected. The calcium concentration at the hyphal tip and 5, 10 and 40μm distal to the tip were calculated to be 65, 17, 38 and 20nM respectively, confirming other studies that suggest a tip-high calcium gradient.

  15. Identifying underground coal mine displacement through field and laboratory laser scanning

    NASA Astrophysics Data System (ADS)

    Slaker, Brent; Westman, Erik

    2014-01-01

    The ability to identify ground movements in the unique environment of an underground coalmine is explored through the use of laser scanning. Time-lapse scans were performed in an underground coal mine to detect rib surface change after different volumes of coal were removed from the mine ribs. Surface changes in the rib as small as 57 cm3 were detected through analysis of surface differences between triangulated surfaces created from point clouds. Results suggest that the uneven geometry, coal reflectance, and small movements of objects and references in the scene due to ventilation air do not significantly influence monitoring ability. Time-lapse scans were also performed on an artificial coal rib constructed to allow the researchers to control deformation and error precisely. A test of displacement measurement precision showed relative standard deviations of <0.1% are attainable with point cloud densities of >3200 pts/m2. Changing the distance and angle of incidence of the artificial coal rib to the scanner had little impact on the accuracy of results beyond the expected reduction due to a smaller point density of the target area. The results collected in this study suggest that laser scanning can be a useful, comprehensive tool for measuring ground change in an underground coal mining environment.

  16. A novel hybrid approach for the extraction of linear/cylindrical features from laser scanning data

    NASA Astrophysics Data System (ADS)

    Lari, Z.; Habib, A.

    2013-10-01

    However, the collected point cloud should undergo manipulation approaches to be utilized for diverse civil, industrial, and military applications. Different processing techniques have consequently been implemented for the extraction of low-level features from this data. Linear/cylindrical features are among the most important primitives that could be extracted from laser scanning data, especially those collected in industrial sites and urban areas. This paper presents a novel approach for the identification, parameterization, and segmentation of these features in a laser point cloud. In the first step of the proposed approach, the points which belong to linear/cylindrical features are detected and their appropriate representation models are chosen based on the principal component analysis of their local neighborhood. The approximate direction and position parameters of the identified linear/cylindrical features are then refined using an iterative line/cylinder fitting procedure. A parameter-domain segmentation method is finally applied to isolate the points which belong to individual linear/cylindrical features in direction and position attribute spaces, respectively. Experimental results from real datasets will demonstrate the feasibility of the proposed approach for the extraction of linear/cylindrical features from laser scanning data.

  17. Surface laser scanning of the cleft palate deformity--validation of the method.

    PubMed

    Foong, K W; Sandham, A; Ong, S H; Wong, C W; Wang, Y; Kassim, A

    1999-09-01

    Innovations in laser technology have led to the development of three-dimensional surface laser digitisation techniques capable of registering surface topology accurately. The clinical application of this technology in cleft palate documentation requires validation of the technique. This study determined the reliability of the surface laser scanning technique and assessed the reliability of interactive three-dimensional landmark localization. Original and duplicate plaster models of an infant with a complete unilateral cleft lip and palate were digitised with the Cyberware 3030R-HIREZ surface laser scanner. Seven anatomic landmarks were marked permanently on the palatal surface of the duplicate model only, which acted as visual cues for landmark localisation. Each model was scanned ten times serially, and ten composite three-dimensional images were obtained for each. On-line interactive computer landmark localisation permitted the assessment of variance for the x, y and z coordinates of each landmark. The precision of the laser scanning technique was found to be less than 0.06 mm in all three axes. Anatomic landmarks with the clearest visual cue were the least variable after ten rounds of scanning. Significant differences existed between visually aided and non-aided landmark localisation (P < 0.05). While landmarks could be localised repeatedly without the aid of a visual marker, landmarks well defined by a clearly visible visual cue on the three-dimensional image were more reliable. PMID:10597347

  18. Geomorphometric analysis of cave ceiling channels mapped with 3-D terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Gallay, Michal; Hochmuth, Zdenko; Kaňuk, Ján; Hofierka, Jaroslav

    2016-05-01

    The change of hydrological conditions during the evolution of caves in carbonate rocks often results in a complex subterranean geomorphology, which comprises specific landforms such as ceiling channels, anastomosing half tubes, or speleothems organized vertically in different levels. Studying such complex environments traditionally requires tedious mapping; however, this is being replaced with terrestrial laser scanning technology. Laser scanning overcomes the problem of reaching high ceilings, providing new options to map underground landscapes with unprecedented level of detail and accuracy. The acquired point cloud can be handled conveniently with dedicated software, but applying traditional geomorphometry to analyse the cave surface is limited. This is because geomorphometry has been focused on parameterization and analysis of surficial terrain. The theoretical and methodological concept has been based on two-dimensional (2-D) scalar fields, which are sufficient for most cases of the surficial terrain. The terrain surface is modelled with a bivariate function of altitude (elevation) and represented by a raster digital elevation model. However, the cave is a 3-D entity; therefore, a different approach is required for geomorphometric analysis. In this paper, we demonstrate the benefits of high-resolution cave mapping and 3-D modelling to better understand the palaeohydrography of the Domica cave in Slovakia. This methodological approach adopted traditional geomorphometric methods in a unique manner and also new methods used in 3-D computer graphics, which can be applied to study other 3-D geomorphological forms.

  19. Automatic Registration of Multiple Laser Scans Using Panoramic RGB and Intensity Images

    NASA Astrophysics Data System (ADS)

    Alba, M.; Barazzetti, L.; Scaioni, M.; Remondino, F.

    2011-09-01

    This paper presents an automated methodology able to register laser scanning point clouds using their panoramic images derived from intensity values or RGB data, the latter obtained from a co-registered camera. Starting from the panorama of each laser scan, a Feature-Based Matching (FBM) algorithm is pairwise applied to extract corresponding key-points. Robust estimators are then used to remove outliers through a generalized rejection procedure encompassing several geometric models. After tracking the twofold key- points across different scan pairs in order to increase the local redundancies, a global Least Squares block adjustment is computed for all scans. Ground control points can also be included at this stage for datum definition and control of block's stability. The proposed method was tested on real case studies and the experiments showed that the procedure is able to deliver the registration of all scans in a fully automatic way. On the other hand, if a higher accuracy is required this solution needs a further ICP refinement.

  20. Bore-Sight Calibration of Multiple Laser Range Finders for Kinematic 3D Laser Scanning Systems

    PubMed Central

    Jung, Jaehoon; Kim, Jeonghyun; Yoon, Sanghyun; Kim, Sangmin; Cho, Hyoungsig; Kim, Changjae; Heo, Joon

    2015-01-01

    The Simultaneous Localization and Mapping (SLAM) technique has been used for autonomous navigation of mobile systems; now, its applications have been extended to 3D data acquisition of indoor environments. In order to reconstruct 3D scenes of indoor space, the kinematic 3D laser scanning system, developed herein, carries three laser range finders (LRFs): one is mounted horizontally for system-position correction and the other two are mounted vertically to collect 3D point-cloud data of the surrounding environment along the system’s trajectory. However, the kinematic laser scanning results can be impaired by errors resulting from sensor misalignment. In the present study, the bore-sight calibration of multiple LRF sensors was performed using a specially designed double-deck calibration facility, which is composed of two half-circle-shaped aluminum frames. Moreover, in order to automatically achieve point-to-point correspondences between a scan point and the target center, a V-shaped target was designed as well. The bore-sight calibration parameters were estimated by a constrained least squares method, which iteratively minimizes the weighted sum of squares of residuals while constraining some highly-correlated parameters. The calibration performance was analyzed by means of a correlation matrix. After calibration, the visual inspection of mapped data and residual calculation confirmed the effectiveness of the proposed calibration approach. PMID:25946627

  1. Benchmarking the Performance of Mobile Laser Scanning Systems Using a Permanent Test Field

    PubMed Central

    Kaartinen, Harri; Hyyppä, Juha; Kukko, Antero; Jaakkola, Anttoni; Hyyppä, Hannu

    2012-01-01

    The performance of various mobile laser scanning systems was tested on an established urban test field. The test was connected to the European Spatial Data Research (EuroSDR) project “Mobile Mapping—Road Environment Mapping Using Mobile Laser Scanning”. Several commercial and research systems collected laser point cloud data on the same test field. The system comparisons focused on planimetric and elevation errors using a filtered digital elevation model, poles, and building corners as the reference objects. The results revealed the high quality of the point clouds generated by all of the tested systems under good GNSS conditions. With all professional systems properly calibrated, the elevation accuracy was better than 3.5 cm up to a range of 35 m. The best system achieved a planimetric accuracy of 2.5 cm over a range of 45 m. The planimetric errors increased as a function of range, but moderately so if the system was properly calibrated. The main focus on mobile laser scanning development in the near future should be on the improvement of the trajectory solution, especially under non-ideal conditions, using both improvements in hardware and software. Test fields are relatively easy to implement in built environments and they are feasible for verifying and comparing the performance of different systems and also for improving system calibration to achieve optimum quality.

  2. D Documentation of a Historical Monument Using Terrestrial Laser Scanning Case Study: Byzantine Water Cistern, Istanbul

    NASA Astrophysics Data System (ADS)

    Temizer, T.; Nemli, G.; Ekizce, E.; Ekizce, A.; Demir, S.; Bayram, B.; Askin, F. H.; Cobanoglu, A. V.; Yilmaz, H. F.

    2013-07-01

    3D modelling of architectural structures for monitoring, conservation and restoration alterations in heritage sites has special challenges for data acquisition and processing. The accuracy of created 3D model is very important. In general, because of the complexity of the structures, 3D modelling can be time consuming and may include some difficulties. 3D terrestrial laser scanning technique is a reliable and advantageous method for reconstruction and conservation of monuments. This technique is commonly acknowledged due to its accuracy, speed and flexibility. Terrestrial laser scanners can be used for documentation of the cultural heritage for the future. But it is also important to understand the capabilities and right conditions of use and limitations of this technology. Istanbul is a rich city with cultural monuments, buildings and cultural heritage. The presented study consists of documentation of a Byzantine water cistern situated underground the court of Sarnicli Han building. The cistern which represents a very good living example of its period has been modelled in 3D by using terrestrial laser scanning technology and the accuracy assessment of this modelling is examined.

  3. Observation of dendritic cell morphology under light, phase-contrast or confocal laser scanning microscopy.

    PubMed

    Tan, Yuen-Fen; Leong, Chooi-Fun; Cheong, Soon-Keng

    2010-12-01

    Dendritic cells (DCs) are professional antigen presenting cells of the immune system. They can be generated in vitro from peripheral blood monocytes supplemented with GM-CSF, IL-4 and TNF alpha. During induction, DCs will increase in size and acquire multiple cytoplasmic projections when compared to their precursor cells such as monocytes or haematopoietic stem cells which are usually round or spherical. Morphology of DCs can be visualized by conventional light microscopy after staining or phase-contrast inverted microscopy or confocal laser scanning microscopy. In this report, we described the morphological appearances of DCs captured using the above-mentioned techniques. We found that confocal laser scanning microscopy yielded DCs images with greater details but the operating cost for such a technique is high. On the other hand, the images obtained through light microscopy after appropriate staining or phase contrast microscopy were acceptable for identification purpose. Besides, these equipments are readily available in most laboratories and the cost of operation is affordable. Nevertheless, morphological identification is just one of the methods to characterise DCs. Other methods such as phenotypic expression markers and mixed leukocyte reactions are additional tools used in the characterisation of DCs. PMID:21329180

  4. Integrating terrestrial laser scanning and repeat field measurements to quantify habitat changes during baseflow recession

    NASA Astrophysics Data System (ADS)

    Woelfle-Erskine, C. A.; Thompson, S. E.

    2013-12-01

    Understanding stream habitat heterogeneity is essential for evaluating stream habitat quality for salmonids, but the variability in pool sizes, groundwater sources, and the associated water quality makes characterization of habitat challenging. Habitat volume and stream connectivity are key drivers of ecosystem processes in spatially-intermittent streams, and strongly influence survival of juvenile salmonids in coastal California. Stream disconnection creates heterogeneous habitats, as disconnected pools are fed by distinct groundwater and hyporheic sources of water containing different concentrations of carbon, oxygen and nutrients. These distinct biogeochemical regimes drive production of benthic macroinvertebrates (salmonids' primary food source) and dissolved oxygen levels, which in turn govern salmonid metabolism. In this study, we use terrestrial laser scans of the streambed, topographic surveys of wetted pools, and repeat field measurements of pool depth to develop a timeseries of finely resolved pool volumes and dry riffle lengths. We overlay repeat water quality measurements onto this surface to visualize how cessation of flow creates heterogeneous habitats influenced by groundwater flux and geomorphic setting. By coupling terrestrial laser scans with traditional surveys, we create high-resolution facies surfaces that can be integrated with timeseries measurements of other biogeochemical data to characterize changes in habitat conditions during baseflow recession. Compared with traditional survey methods, this method yields improved qualitative descriptions of habitat fragmentation via visualizations and spatially and temporally explicit quantification of aquatic and riparian habitat characteristics that drive salmonid over-summer survival.

  5. Bore-Sight Calibration of Multiple Laser Range Finders for Kinematic 3D Laser Scanning Systems.

    PubMed

    Jung, Jaehoon; Kim, Jeonghyun; Yoon, Sanghyun; Kim, Sangmin; Cho, Hyoungsig; Kim, Changjae; Heo, Joon

    2015-01-01

    The Simultaneous Localization and Mapping (SLAM) technique has been used for autonomous navigation of mobile systems; now, its applications have been extended to 3D data acquisition of indoor environments. In order to reconstruct 3D scenes of indoor space, the kinematic 3D laser scanning system, developed herein, carries three laser range finders (LRFs): one is mounted horizontally for system-position correction and the other two are mounted vertically to collect 3D point-cloud data of the surrounding environment along the system's trajectory. However, the kinematic laser scanning results can be impaired by errors resulting from sensor misalignment. In the present study, the bore-sight calibration of multiple LRF sensors was performed using a specially designed double-deck calibration facility, which is composed of two half-circle-shaped aluminum frames. Moreover, in order to automatically achieve point-to-point correspondences between a scan point and the target center, a V-shaped target was designed as well. The bore-sight calibration parameters were estimated by a constrained least squares method, which iteratively minimizes the weighted sum of squares of residuals while constraining some highly-correlated parameters. The calibration performance was analyzed by means of a correlation matrix. After calibration, the visual inspection of mapped data and residual calculation confirmed the effectiveness of the proposed calibration approach. PMID:25946627

  6. Laser Scanning of a Monolithic Column during Processing in Middle Egypt

    NASA Astrophysics Data System (ADS)

    Ajioka, O.; Hori, Y.

    2011-09-01

    From ancient quarries around Akoris in Middle Egypt, which belong to the Ptolemaic and Roman periods, the stone blocks could be carried to the working area located in the outside of the city. Those blocks included a giant monolithic column measured approximately 14m in length, which had been cracked for reasons unknown and must have contributed to disuse of monolith. The first deal is a comparison of plans drawn by the point clouds by laser scanning with those coming from plane-tabling, which had been one of popular methods for measuring in the last century. This part shows how the laser scanning technology is useful in far better measuring and documentation of the site. The second discuss is about a detailed assessment of the procedure of processing through the observation of chisel marks and the detail analysis about the 3 dimensional data. In the result, we are succeed to show the restoration of the procedure of the proceedings using guidelines and a wooden curve since we concentrate attention on the point of abstracting the centre line and shaving the surface into the round shape.

  7. Effects of scanning orientation on outlier formation in 3D laser scanning of reflective surfaces

    NASA Astrophysics Data System (ADS)

    Wang, Yutao; Feng, Hsi-Yung

    2016-06-01

    Inspecting objects with reflective surfaces using 3D laser scanning is a demanded but challenging part inspection task due to undesirable specular reflections, which produce extensive outliers in the scanned point cloud. These outliers need to be removed in order to alleviate subsequent data processing issues. Many existing automatic outlier removal methods do not detect outliers according to the outlier formation properties. As a result, these methods only offer limited capabilities in removing extensive and complex outliers from scanning objects with reflective surfaces. This paper reports an empirical study which experimentally investigates the outlier formation characteristics in relation to the scanning orientation of the laser probe. The objective is to characterize the scanning orientation effects on outlier formation in order to facilitate the development of an effective outlier detection and removal method. Such an experimental investigation was hardly done before. It has been found in this work that scanning orientation can directly affect outlier extensity and occurrence in 3D laser scanning. A general guidance on proper scan path planning can then be provided with an aim to reduce the occurrence of outliers. Further, the observed dependency of outlier formation on scanning orientation can be exploited to facilitate effective and automatic outlier detection and removal.

  8. Application of laser scan microscopy in vivo for wound healing characterization

    NASA Astrophysics Data System (ADS)

    Czaika, V.; Alborova, A.; Sterry, W.; Lademann, J.; Koch, S.

    2010-09-01

    Considering the advancing age of the population, wound healing disturbances are becoming increasingly important in clinical routine. The development of wound healing creams and lotions as well as therapy control require an objective evaluation of the wound healing process, which represents the destruction of the barrier. Therefore, transepidermal water loss measurements are often carried out. These measurements have the disadvantage that they are disturbed by the interstitial fluid, which is located on the surface of chronic wounds and also by water components of the creams and lotions. Additionally, the TEWL measurements are very sensitive to temperature changes and to the anxiety of the volunteers. In the present study, in vivo laser scanning microscopy was used to analyze the reepithelialization and barrier recovery of standardized wounds produced by the suction blister technique. It was demonstrated that this non-invasive, on-line spectroscopic method allows the evaluation of the wound healing process, without any disturbances. It was found that the wound healing starts not only from the edges of the wound, but also out of the hair follicles. The in vivo laser scanning microscopy is well suited to evaluate the efficacy of wound healing creams and for therapy control.

  9. Automatic registration of laser-scanned point clouds based on planar features

    NASA Astrophysics Data System (ADS)

    Li, Minglei; Gao, Xinyuan; Wang, Li; Li, Guangyun

    2016-03-01

    Automatic multistation registration of laser-scanned point clouds is a research hotspot in laser-scanned point clouds registration. Some targets such as common buildings have plenty of planar features, and using these features as constraints properly can bring about high accuracy registration results. Starting from this, a new automatic multistation registration method using homologous planar features of two scan stations was proposed. In order to recognize planes from different scan stations and get plane equations in corresponding scan station coordinate systems, k-means dynamic clustering method was improved to be adaptive and robust. And to match the homologous planes of the two scan stations, two different procedures were proposed, respectively, one of which was based on the "common" relationship between planes and the other referenced RANSAC algorithm. And the transformation parameters of the two scan station coordinate systems were calculated after homologous plane matching. Finally, the transformation parameters based on the optimal match of planes was adopted as the final registration result. Comparing with ICP algorithm in experiment, the method is proved to be effective.

  10. Multispectral airborne laser scanning - a new trend in the development of LiDAR technology

    NASA Astrophysics Data System (ADS)

    Bakuła, K.

    2015-12-01

    Airborne laser scanning (ALS) is the one of the most accurate remote sensing techniques for data acquisition where the terrain and its coverage is concerned. Modern scanners have been able to scan in two or more channels (frequencies of the laser) recently. This gives the rise to the possibility of obtaining diverse information about an area with the different spectral properties of objects. The paper presents an example of a multispectral ALS system - Titan by Optech - with the possibility of data including the analysis of digital elevation models accuracy and data density. As a result of the study, the high relative accuracy of LiDAR acquisition in three spectral bands was proven. The mean differences between digital terrain models (DTMs) were less than 0.03 m. The data density analysis showed the influence of the laser wavelength. The points clouds that were tested had average densities of 25, 23 and 20 points per square metre respectively for green (G), near-infrared (NIR) and shortwave-infrared (SWIR) lasers. In this paper, the possibility of the generation of colour composites using orthoimages of laser intensity reflectance and its classification capabilities using data from airborne multispectral laser scanning for land cover mapping are also discussed and compared with conventional photogrammetric techniques.

  11. Laser Scanning In Vivo Confocal Microscopy of Clear Grafts after Penetrating Keratoplasty

    PubMed Central

    Wang, Dai; Song, Peng; Wang, Shuting; Sun, Dapeng; Wang, Yuexin; Zhang, Yangyang

    2016-01-01

    Purpose. To evaluate the changes of keratocytes and dendritic cells in the central clear graft by laser scanning in vivo confocal microscopy after penetrating keratoplasty (PK). Methods. Thirty adult subjects receiving PK at Shandong Eye Institute and with clear grafts and no sign of immune rejection after surgery were recruited into this study, and 10 healthy adults were controls. The keratocytes and dendritic cells in the central graft were evaluated by laser scanning confocal microscopy, as well as epithelium cells, keratocytes, corneal endothelium cells, and corneal nerves (especially subepithelial plexus nerves). Results. Median density of subepithelial plexus nerves, keratocyte density in each layer of the stroma, and density of corneal endothelium cells were all lower in clear grafts than in controls. The dendritic cells of five (16.7%) patients were active in Bowman's membrane and stromal membrane of the graft after PK. Conclusions. Activated dendritic cells and Langerhans cells could be detected in some of the clear grafts, which indicated that the subclinical stress of immune reaction took part in the chronic injury of the clear graft after PK, even when there was no clinical rejection episode. PMID:27034940

  12. Compact two-photon laser-scanning microscope made from minimally modified commercial components

    NASA Astrophysics Data System (ADS)

    Iyer, Vijay; Hoogland, Tycho; Losavio, Bradley E.; McQuiston, A. R.; Saggau, Peter

    2002-06-01

    A compact two-photon laser-scanning microscope (TPLSM) was constructed using a diode-pumped, mode-locked Nd:YLF laser (Biolight 1000, Coherent Laser Group) and a small confocal laser scan-head (PCM2000, Nikon Bioscience). The laser emits at 1047nm and is fiber-coupled to a compact compressor unit producing a pulse-width of ~175fsec. Both the pulse compressor and confocal scan head were interfaced on a small optical breadboard that was directly attached to an upright research microscope (Eclipse E600FN, Nikon Bioscience). Two-photon fluorescence emitted from the specimen was collected into a multimode fiber and transmitted directly to an external PMT supplied with the Nikon confocal system. The modifications to the scanhead were minimal (a single mirror replacement) and did not interfere with its confocal function. The resulting system offers several advantages: compact size, turnkey operation, and the ability to translate the microscope rather than an often delicate specimen. In addition, it is possible to switch between confocal and two-photon operation, allowing for straightforward comparison. Using this compact TPLSM, we obtained structural and functional images from hippocampal neurons in living brain slices using commonly available fluorophores.

  13. Laser-scanned fluorescence of nonlased/normal, lased/normal, nonlased/carious, and lased/carious enamel

    NASA Astrophysics Data System (ADS)

    Zakariasen, Kenneth L.; Barron, Joseph R.; Paton, Barry E.

    1992-06-01

    Research has shown that low levels of CO2 laser irradiation raise enamel resistance to sub-surface demineralization. Additionally, laser scanned fluorescence analysis of enamel, as well a laser and white light reflection studies, have potential for both clinical diagnosis and comparative research investigations of the caries process. This study was designed to compare laser fluorescence and laser/white light reflection of (1) non-lased/normal with lased/normal enamel and (2) non-lased/normal with non-lased/carious and lased/carious enamel. Specimens were buccal surfaces of extracted third molars, coated with acid resistant varnish except for either two or three 2.25 mm2 windows (two window specimens: non-lased/normal, lased/normal--three window specimens: non-lased/normal, non-lased carious, lased/carious). Teeth exhibiting carious windows were immersed in a demineralizing solution for twelve days. Non-carious windows were covered with wax during immersion. Following immersion, the wax was removed, and fluorescence and laser/white light reflection analyses were performed on all windows utilizing a custom scanning laser fluorescence spectrometer which focuses light from a 25 mWatt He-Cd laser at 442 nm through an objective lens onto a cross-section >= 3 (mu) in diameter. For laser/white light reflection analyses, reflected light intensities were measured. A HeNe laser was used for laser light reflection studies. Following analyses, the teeth are sectioned bucco-lingually into 80 micrometers sections, examined under polarized light microscopy, and the lesions photographed. This permits comparison between fluorescence/reflected light values and the visualized decalcification areas for each section, and thus comparisons between various enamel treatments and normal enamel. The enamel specimens are currently being analyzed.

  14. An Integrated Flexible Self-calibration Approach for 2D Laser Scanning Range Finders Applied to the Hokuyo UTM-30LX-EW

    NASA Astrophysics Data System (ADS)

    Mader, D.; Westfeld, P.; Maas, H.-G.

    2014-06-01

    The paper presents a flexible approach for the geometric calibration of a 2D infrared laser scanning range finder. It does not require spatial object data, thus avoiding the time-consuming determination of reference distances or coordinates with superior accuracy. The core contribution is the development of an integrated bundle adjustment, based on the flexible principle of a self-calibration. This method facilitates the precise definition of the geometry of the scanning device, including the estimation of range-measurement-specific correction parameters. The integrated calibration routine jointly adjusts distance and angular data from the laser scanning range finder as well as image data from a supporting DSLR camera, and automatically estimates optimum observation weights. The validation process carried out using a Hokuyo UTM-30LX-EW confirms the correctness of the proposed functional and stochastic contexts and allows detailed accuracy analyses. The level of accuracy of the observations is computed by variance component estimation. For the Hokuyo scanner, we obtained 0.2% of the measured distance in range measurement and 0.2 deg for the angle precision. The RMS error of a 3D coordinate after the calibration becomes 5 mm in lateral and 9 mm in depth direction. Particular challenges have arisen due to a very large elliptical laser beam cross-section of the scanning device used.

  15. Laser Scanning for the definition of high resolution topography in the Apuan Alps (IT) marble district

    NASA Astrophysics Data System (ADS)

    Riccucci, Silvia; Salvini, Riccardo; Francioni, Mirko

    2010-05-01

    The present paper describes the results of five laser scanning surveys performed by a Leica™ ScanStation2 with the aim of producing an high definition topography of a quarry, at the scale of 1:1,000. The project comes from a joint research carried out by the Authors in collaboration with the Local Sanitary Unit Agency (ASL n.1) of Massa and Carrara (IT). The main objective of this work has been the survey of both the exploited quarry walls and the upper residual and natural slopes. The area of interest is characterized by several quarry fronts which develop to variable and alternate directions to create very evident rock spurs, from NW-SE to NE-SW trending for a total wideness of about 2 hectares. Moreover, the quarry walls are sub-vertical and sometimes overhang by a total height of 100 m in respect to the quarry floor. Differential GPS and orthometric correction have been applied in order to co-register and to georeference the five point clouds; for these purposes a series of optical targets have been measured using a Laser Total Station. The subsequent phase has been the mesh construction and editing, from which a topographic map, 25 cm equidistance contours lines, has been created. The planimetric map shows the position and the geometry of crests, banks, escarpments, walls and all others exploitation features and the characteristics of the upper natural slopes. Morphological profiles along the maximum slope have been realized in order to better plan the future extractive activities according to the regional law. In order to make easier the prospective observation of detailed and overall areas, 3D views of multi-directional orientation have been realized. The produced data has been published by using the free LeicaTM TruView plug-in for Internet Explorer in a way to easily view the photographs and to measure the laser scan point clouds. Processing results have highlighted the higher spatial resolution of data coming from laser scanning in respect to the

  16. Gravity combined with laser-scan in Grotta Gigante: a benchmark cave for gravity studies

    NASA Astrophysics Data System (ADS)

    Pivetta, Tommaso; Braitenberg, Carla

    2014-05-01

    Laser scanning has become one of the most important topographic techniques in the last decades, due to its ability to reconstruct complex surfaces with high resolution and precision and due to its fast acquisition time. Recently a laser-scan survey has been acquired (Fingolo et al., 2011) in the "Grotta Gigante" cave near Trieste, Italy, the biggest cave worldwide according to the Guinness Awards. In this paper this survey is used to obtain a 3D discretization of the cave with prisms. Then through this new model, with the densities derived from campaign measurements, the exact gravimetric effect of the structure was computed (Nagy et al., 2000) and compared with the gravity observation at the surface. The transition from the cloud of laser-scan points to the prism model was carried out by different computer elaborations; first of all the reduction of the data density through an averaging process that allows to pass from over 10000 points/m2 to less than 10points/m2. Then the whole dataset was filtered from the outliers by the means of a simple quadratic surface that fit the data (Turner, 1999). The reduced data points should be divided into the 2 surfaces of top and bottom, that are used to define the prisms. This step was performed using the local regression method (Loess) to calculate a surface located halfway between top and bottom points. Once the top and bottom interfaces were obtained it was possible to get the final prism representation and calculate the gravity signal. The observed Bouguer field is explained very well by our model and the residuals are used to evaluate possible secondary caves. The final prism model together with the gravity database on surface and inside the cave form a perfect benchmark to test forward and inverse potential field algorithms. References Fingolo M., Facco L., Ceccato A., Breganze C., Paganini P., Cezza M., Grotta Gigante di Trieste. Tra realtà virtuale e rilievi 3D ad alta risoluzione, Veneto Geologi, 75, pp.21-25, 2011

  17. Capturing and modelling high-complex alluvial topography with UAS-borne laser scanning

    NASA Astrophysics Data System (ADS)

    Mandlburger, Gottfried; Wieser, Martin; Pfennigbauer, Martin

    2015-04-01

    Due to fluvial activity alluvial forests are zones of highest complexity and relief energy. Alluvial forests are dominated by new and pristine channels in consequence of current and historic flood events. Apart from topographic features, the vegetation structure is typically very complex featuring, both, dense under story as well as high trees. Furthermore, deadwood and debris carried from upstream during periods of high discharge within the river channel are deposited in these areas. Therefore, precise modelling of the micro relief of alluvial forests using standard tools like Airborne Laser Scanning (ALS) is hardly feasible. Terrestrial Laser Scanning (TLS), in turn, is very time consuming for capturing larger areas as many scan positions are necessary for obtaining complete coverage due to view occlusions in the forest. In the recent past, the technological development of Unmanned Arial Systems (UAS) has reached a level that light-weight survey-grade laser scanners can be operated from these platforms. For capturing alluvial topography this could bridge the gap between ALS and TLS in terms of providing a very detailed description of the topography and the vegetation structure due to the achievable very high point density of >100 points per m2. In our contribution we demonstrate the feasibility to apply UAS-borne laser scanning for capturing and modelling the complex topography of the study area Neubacher Au, an alluvial forest at the pre-alpine River Pielach (Lower Austria). The area was captured with Riegl's VUX-1 compact time-of-flight laser scanner mounted on a RiCopter (X-8 array octocopter). The scanner features an effective scan rate of 500 kHz and was flown in 50-100 m above ground. At this flying height the laser footprint is 25-50 mm allowing mapping of very small surface details. Furthermore, online waveform processing of the backscattered laser energy enables the retrieval of multiple targets for single laser shots resulting in a dense point cloud of

  18. Soil water erosion processes in mountain forest catchment - analysis by using terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Dąbek, Paweł; Żmuda, Romuald; Szczepański, Jakub; Ćmielewski, Bartłomiej; Patrzałek, Ciechosław

    2013-04-01

    The paper presents the results of the analysis of the water erosion processes of soil occurring in forestry mountain catchment area in the region of West Sudetes Mountain in Poland. The research was carried out within the experimental area of skid trails (operational trails), which were used to the end of 2010 in obtaining wood and its mechanical transport to the place of storage. As a consequence of forestry works that were carried out it was changing the natural structure of ground and its surface on the wooded slopes, which, combined with the favorable hydro-meteorological conditions contributed to the intensification of the water erosion processes of soil on surface of trails. For the implementation of the research project of the analysis of water erosion processes in the forestry catchment area innovative was used terrestrial laser scanning. Using terrestrial laser scanning has enabled the analysis of the dynamics of erosion processes both in time, as well as in spatial and quantitative terms. Scanning was performed at a resolution of 4 mm, resulting in 62 500 points per 1 square meter. After filtering the data were interpolated to other resolution of 1 cm, which can identify even the smallest linear and surface effects of erosion. While installed on the experimental area, along the skid trails, anti-erosion barriers in order to reduce transport eroded material and allow its accumulation. Allowed to precisely determine the location of areas of accumulation, the rate and amount of accumulated material. The result of the analyses that was carried out is identification areas of denudation of the eroded material, and also determine the intensity of the erosion processes and their quantitative analysis. The long-term researches on hydrological conditions and forest complexes functioning show that forest effectively stores water, limits linear and surface flow and delays water outflow from a catchment. Carried out a research project using the terrestrial laser

  19. Fusion of image and laser-scanning data in a large-scale 3D virtual environment

    NASA Astrophysics Data System (ADS)

    Shih, Jhih-Syuan; Lin, Ta-Te

    2013-05-01

    Construction of large-scale 3D virtual environment is important in many fields such as robotic navigation, urban planning, transportation, and remote sensing, etc. Laser scanning approach is the most common method used in constructing 3D models. This paper proposes an automatic method to fuse image and laser-scanning data in a large-scale 3D virtual environment. The system comprises a laser-scanning device installed on a robot platform and the software for data fusion and visualization. The algorithms of data fusion and scene integration are presented. Experiments were performed for the reconstruction of outdoor scenes to test and demonstrate the functionality of the system. We also discuss the efficacy of the system and technical problems involved in this proposed method.

  20. Application of a Hybrid 3D-2D Laser Scanning System to the Characterization of Slate Slabs

    PubMed Central

    López, Marcos; Martínez, Javier; Matías, José María; Vilán, José Antonio; Taboada, Javier

    2010-01-01

    Dimensional control based on 3D laser scanning techniques is widely used in practice. We describe the application of a hybrid 3D-2D laser scanning system to the characterization of slate slabs with structural defects that are difficult for the human eye to characterize objectively. Our study is based on automating the process using a 3D laser scanner and a 2D camera. Our results demonstrate that the application of this hybrid system optimally characterizes slate slabs in terms of the defects described by the Spanish UNE-EN 12326-1 standard. PMID:22219696

  1. Static terrestrial laser scanning of juvenile understory trees for field phenotyping

    NASA Astrophysics Data System (ADS)

    Wang, Huanhuan; Lin, Yi

    2014-11-01

    This study was to attempt the cutting-edge 3D remote sensing technique of static terrestrial laser scanning (TLS) for parametric 3D reconstruction of juvenile understory trees. The data for test was collected with a Leica HDS6100 TLS system in a single-scan way. The geometrical structures of juvenile understory trees are extracted by model fitting. Cones are used to model trunks and branches. Principal component analysis (PCA) is adopted to calculate their major axes. Coordinate transformation and orthogonal projection are used to estimate the parameters of the cones. Then, AutoCAD is utilized to simulate the morphological characteristics of the understory trees, and to add secondary branches and leaves in a random way. Comparison of the reference values and the estimated values gives the regression equation and shows that the proposed algorithm of extracting parameters is credible. The results have basically verified the applicability of TLS for field phenotyping of juvenile understory trees.

  2. The Use of Computer Vision Algorithms for Automatic Orientation of Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Markiewicz, Jakub Stefan

    2016-06-01

    The paper presents analysis of the orientation of terrestrial laser scanning (TLS) data. In the proposed data processing methodology, point clouds are considered as panoramic images enriched by the depth map. Computer vision (CV) algorithms are used for orientation, which are applied for testing the correctness of the detection of tie points and time of computations, and for assessing difficulties in their implementation. The BRISK, FASRT, MSER, SIFT, SURF, ASIFT and CenSurE algorithms are used to search for key-points. The source data are point clouds acquired using a Z+F 5006h terrestrial laser scanner on the ruins of Iłża Castle, Poland. Algorithms allowing combination of the photogrammetric and CV approaches are also presented.

  3. Fast 3D visualization of endogenous brain signals with high-sensitivity laser scanning photothermal microscopy.

    PubMed

    Miyazaki, Jun; Iida, Tadatsune; Tanaka, Shinji; Hayashi-Takagi, Akiko; Kasai, Haruo; Okabe, Shigeo; Kobayashi, Takayoshi

    2016-05-01

    A fast, high-sensitivity photothermal microscope was developed by implementing a spatially segmented balanced detection scheme into a laser scanning microscope. We confirmed a 4.9 times improvement in signal-to-noise ratio in the spatially segmented balanced detection compared with that of conventional detection. The system demonstrated simultaneous bi-modal photothermal and confocal fluorescence imaging of transgenic mouse brain tissue with a pixel dwell time of 20 μs. The fluorescence image visualized neurons expressing yellow fluorescence proteins, while the photothermal signal detected endogenous chromophores in the mouse brain, allowing 3D visualization of the distribution of various features such as blood cells and fine structures probably due to lipids. This imaging modality was constructed using compact and cost-effective laser diodes, and will thus be widely useful in the life and medical sciences. PMID:27231615

  4. Segmentation-Based Ground Points Detection from Mobile Laser Scanning Point Cloud

    NASA Astrophysics Data System (ADS)

    Lin, X.; Zhang, J.

    2015-06-01

    In most Mobile Laser Scanning (MLS) applications, filtering is a necessary step. In this paper, a segmentation-based filtering method is proposed for MLS point cloud, where a segment rather than an individual point is the basic processing unit. Particularly, the MLS point cloud in some blocks are clustered into segments by a surface growing algorithm, then the object segments are detected and removed. A segment-based filtering method is employed to detect the ground segments. Two MLS point cloud datasets are used to evaluate the proposed method. Experiments indicate that, compared with the classic progressive TIN (Triangulated Irregular Network) densification algorithm, the proposed method is capable of reducing the omission error, the commission error and total error by 3.62%, 7.87% and 5.54% on average, respectively.

  5. Further study of trichosanthin's effect on mouse embryos with confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Xu, Hui; Zhang, Chunyang; Ma, Hui; Chen, Die Yan

    2001-09-01

    Trichosanthin(TCS), a ribosome inactivating protein extracted from the root tuber of a traditional Chinese medicine herb Tian Huo Fen(THF), possessed abortifacient, anti-tumor and anti-human immunodeficiency virus(HIV) activities. For centuries in China, THF has been used as an effective folk medicine to terminate early and midtrimester pregnancies and to treat ectopic pregnancies, hydatidiform moles and trophoblastic tumor. We observed the changes in reactive oxygen species and intracellular calcium in mouse embryos induced by TCS with confocal laser scanning microscopy in combination with the fluorescene diacetate (DCFHDA) and Fluo-3-AM. The results indicated that TCS induced increase in intracellular calcium and production of reactive oxygen species in mouse embryos , and TCS inhibited the development of mouse embryos effectively. Mouse embryos of different developmental stages before implantation are used in the experiments. This provides new insight into mechanism for abortifacient activity of TCS.

  6. Parallel deconvolution of large 3D images obtained by confocal laser scanning microscopy.

    PubMed

    Pawliczek, Piotr; Romanowska-Pawliczek, Anna; Soltys, Zbigniew

    2010-03-01

    Various deconvolution algorithms are often used for restoration of digital images. Image deconvolution is especially needed for the correction of three-dimensional images obtained by confocal laser scanning microscopy. Such images suffer from distortions, particularly in the Z dimension. As a result, reliable automatic segmentation of these images may be difficult or even impossible. Effective deconvolution algorithms are memory-intensive and time-consuming. In this work, we propose a parallel version of the well-known Richardson-Lucy deconvolution algorithm developed for a system with distributed memory and implemented with the use of Message Passing Interface (MPI). It enables significantly more rapid deconvolution of two-dimensional and three-dimensional images by efficiently splitting the computation across multiple computers. The implementation of this algorithm can be used on professional clusters provided by computing centers as well as on simple networks of ordinary PC machines. PMID:19725070

  7. Calibration of area based diameter distribution with individual tree based diameter estimates using airborne laser scanning

    NASA Astrophysics Data System (ADS)

    Xu, Qing; Hou, Zhengyang; Maltamo, Matti; Tokola, Timo

    2014-07-01

    Diameter distribution is essential for calculating stem volume and timber assortments of forest stands. A new method was proposed in this study to improve the estimation of stem volume and timber assortments, by means of combining the Area-based approach (ABA) and individual tree detection (ITD), the two main approaches to deriving forest attributes from airborne laser scanning (ALS) data. Two methods, replacement, and histogram matching were employed to calibrate ABA-derived diameter distributions with ITD-derived diameter estimates at plot level. The results showed that more accurate estimates were obtained when calibrations were applied. In view of the highest accuracy between ABA and ITD, calibrated diameter distributions decreased its relative RMSE of the estimated entire growing stock, saw log and pulpwood fractions by 2.81%, 3.05% and 7.73% points at best, respectively. Calibration improved pulpwood fraction significantly, which contributed to the negligible bias of the estimated entire growing stock.

  8. Human hand-transmitted vibration measurements on pedestrian controlled tractor operators by a laser scanning vibrometer.

    PubMed

    Deboli, R; Miccoli, G; Rossi, G L

    1999-06-01

    A first application of a new measurement technique to detect vibration transmitted to the human body in working conditions is presented. The technique is based on the use of a laser scanning vibrometer. It was previously developed, analysed and tested using laboratory test benches with electrodynamical exciters, and comparisons with traditional measurement techniques based on accelerometers were made. First, results of tests performed using a real machine generating vibration are illustrated. The machine used is a pedestrian-controlled tractor working in a fixed position. Reference measurements by using the accelerometer have been simultaneously performed while scanning the hand surface by the laser-based measurement system. Results achieved by means of both measurement techniques have been processed, analysed, compared and used to calculate transmissibility maps of the hands of three subjects. PMID:10340028

  9. Evaluation of the Cytotoxic Behavior of Fungal Extracellular Synthesized Ag Nanoparticles Using Confocal Laser Scanning Microscope

    PubMed Central

    Salaheldin, Taher A.; Husseiny, Sherif M.; Al-Enizi, Abdullah M.; Elzatahry, Ahmed; Cowley, Alan H.

    2016-01-01

    Silver nanoparticles have been synthesized by subjecting a reaction medium to a Fusarium oxysporum biomass at 28 °C for 96 h. The biosynthesized Ag nanoparticles were characterized on the basis of their anticipated peak at 405 nm using UV-Vis-NIR spectroscopy. Structural confirmation was evident from the characteristic X-ray diffraction (XRD) pattern, high-resolution transmission electron Microscopy (HRTEM) and the particle size analyzer. The Ag nanoparticles were of dimension 40 ± 5 nm and spherical in shape. The study mainly focused on using the confocal laser scanning microscope (CLSM) to examine the cytotoxic activities of fungal synthesized Ag nanoparticles on a human breast carcinoma cell line MCF7 cell, which featured remarkable vacuolation, thus indicating a potent cytotoxic activity. PMID:26950118

  10. Starch/carrageenan/milk proteins interactions studied using multiple staining and Confocal Laser Scanning Microscopy.

    PubMed

    Matignon, A; Moulin, G; Barey, P; Desprairies, M; Mauduit, S; Sieffermann, J M; Michon, C

    2014-01-01

    This study focused on the effects of the interactions between modified waxy maize starch, kappa carrageenan and skim milk on the microstructure of their mixed systems using Confocal Laser Scanning Microscopy (CLSM). A multiple staining of the components was set up with a view to improving starch covalent staining. In starch/carrageenan pasted mixtures, carrageenan was found to adsorb on and penetrate slightly into the starch granules, whereas no interactions were observed between starch and milk proteins. In ternary mixtures, interactions between starch granules and carrageenan were no longer observed, even when milk proteins were added after starch swelling in the carrageenan solution, thus showing preferential interactions between carrageenan/milk proteins in comparison to carrageenan/starch granules. Modifying the blending order of the components led to microstructure differences depending on several parameters such as starch/carrageenan interactions, carrageenan/milk proteins network structure, level of starch granules disruption and amylopectin contribution to the microstructure. PMID:24274517

  11. Writing of rare-earth ion doped lithium niobate line patterns in glass by laser scanning

    NASA Astrophysics Data System (ADS)

    Honma, T.; Komatsu, T.; Zhao, D.; Jain, H.

    2009-02-01

    A glass of Er3+ doped Li2O-Nb2O5-SiO2-B2O3 with an addition of CuO or Sm2O3 crystallizing nonlinear optical lithium niobate LiNbO3 (LN) is developed. Crystalline lines of LN have been fabricated on the glass surface by continuous wave Yb fiber laser irradiations with a wavelength of 1080 nm. The laser written LN crystalline lines have been found, by means of electron back scattering method, micro-Raman and second harmonic experiments, to be well oriented along the laser scanning direction. For the testing of optical waveguides crystal lines exhibit light confinements due to the refractive index (n) changes between the patterned line (n~2.2) and the glass matrix (n=1.7). The analysis of the confocal micro-luminescence spectra obtained for the crystalline line indicates the incorporation of Er3+ ions into LN crystals.

  12. A handheld laser scanning confocal reflectance imaging–confocal Raman microspectroscopy system

    PubMed Central

    Patil, Chetan A.; Arrasmith, Christopher L.; Mackanos, Mark A.; Dickensheets, David L.; Mahadevan-Jansen, Anita

    2012-01-01

    Confocal reflectance microscopy and confocal Raman spectroscopy have shown potential for non-destructive analysis of samples at micron-scale resolutions. Current studies utilizing these techniques often employ large bench-top microscopes, and are not suited for use outside of laboratory settings. We have developed a microscope which combines laser scanning confocal reflectance imaging and confocal Raman spectroscopy into a compact handheld probe that is capable of high-resolution imaging and spectroscopy in a variety of settings. The compact size of the probe is largely due to the use of a MEMS mirror for beam scanning. The probe is capable of axial resolutions of up to 4 μm for the confocal imaging channel and 10 μm for the confocal Raman spectroscopy channel. Here, we report instrument design, characterize optical performance, and provide images and spectra from normal skin to demonstrate the instrument’s capabilities for clinical diagnostics. PMID:22435097

  13. An alternative method of promoter assessment by confocal laser scanning microscopy.

    PubMed

    Sahoo, Dipak K; Ranjan, Rajiv; Kumar, Deepak; Kumar, Alok; Sahoo, Bhabani S; Raha, Sumita; Maiti, Indu B; Dey, Nrisingha

    2009-10-01

    A rapid and useful method of promoter activity analysis using techniques of confocal laser scanning microscopy (CLSM) is described in the present study. The activities of some pararetroviral promoters such as CaMV35S (Cauliflower mosaic virus), FMVSgt3 (Figwort mosaic virus sub-genomic transcript) and MMVFLt12 (Mirabilis mosaic virus full-length transcript) coupled to GFP (green fluorescent protein) and GUS (beta-glucuronidase) reporter genes were determined simultaneously by the CLSM technique and other available conventional methods for reporter gene assay based on relevant biochemical and molecular approaches. Consistent and comparable results obtained by CLSM as well as by other conventional assay methods confirm the effectiveness of the CLSM approach for assessment of promoter activity. Hence the CLSM method can be suggested as an alternative way for promoter analysis on the basis of high throughput. PMID:19540268

  14. Spatiotemporal Rank Filtering Improves Image Quality Compared to Frame Averaging in 2-Photon Laser Scanning Microscopy

    PubMed Central

    Pinkard, Henry; Corbin, Kaitlin; Krummel, Matthew F.

    2016-01-01

    Live imaging of biological specimens using optical microscopy is limited by tradeoffs between spatial and temporal resolution, depth into intact samples, and phototoxicity. Two-photon laser scanning microscopy (2P-LSM), the gold standard for imaging turbid samples in vivo, has conventionally constructed images with sufficient signal-to-noise ratio (SNR) generated by sequential raster scans of the focal plane and temporal integration of the collected signals. Here, we describe spatiotemporal rank filtering, a nonlinear alternative to temporal integration, which makes more efficient use of collected photons by selectively reducing noise in 2P-LSM images during acquisition. This results in much higher SNR while preserving image edges and fine details. Practically, this allows for at least a four fold decrease in collection times, a substantial improvement for time-course imaging in biological systems. PMID:26938064

  15. Knowledge based reconstruction of building models from terrestrial laser scanning data

    NASA Astrophysics Data System (ADS)

    Pu, Shi; Vosselman, George

    This paper presents an automatic method for reconstruction of building façade models from terrestrial laser scanning data. Important façade elements such as walls and roofs are distinguished as features. Knowledge about the features' sizes, positions, orientations, and topology is then introduced to recognize these features in a segmented laser point cloud. An outline polygon of each feature is generated by least squares fitting, convex hull fitting or concave polygon fitting, according to the size of the feature. Knowledge is used again to hypothesise the occluded parts from the directly extracted feature polygons. Finally, a polyhedron building model is combined from extracted feature polygons and hypothesised parts. The reconstruction method is tested with two data sets containing various building shapes.

  16. Fast 3D visualization of endogenous brain signals with high-sensitivity laser scanning photothermal microscopy

    PubMed Central

    Miyazaki, Jun; Iida, Tadatsune; Tanaka, Shinji; Hayashi-Takagi, Akiko; Kasai, Haruo; Okabe, Shigeo; Kobayashi, Takayoshi

    2016-01-01

    A fast, high-sensitivity photothermal microscope was developed by implementing a spatially segmented balanced detection scheme into a laser scanning microscope. We confirmed a 4.9 times improvement in signal-to-noise ratio in the spatially segmented balanced detection compared with that of conventional detection. The system demonstrated simultaneous bi-modal photothermal and confocal fluorescence imaging of transgenic mouse brain tissue with a pixel dwell time of 20 μs. The fluorescence image visualized neurons expressing yellow fluorescence proteins, while the photothermal signal detected endogenous chromophores in the mouse brain, allowing 3D visualization of the distribution of various features such as blood cells and fine structures probably due to lipids. This imaging modality was constructed using compact and cost-effective laser diodes, and will thus be widely useful in the life and medical sciences. PMID:27231615

  17. Characterization of acoustic lenses with the Foucault test by confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Ahmed Mohamed, E. T.; Abdelrahman, A.; Pluta, M.; Grill, W.

    2010-03-01

    In this work, the Foucault knife-edge test, which has traditionally been known as the classic test for optical imaging devices, is used to characterize an acoustic lens for operation at 1.2 GHz. A confocal laser scanning microscope (CLSM) was used as the illumination and detection device utilizing its pinhole instead of the classical knife edge that is normally employed in the Foucault test. Information about the geometrical characteristics, such as the half opening angle of the acoustic lens, were determined as well as the quality of the calotte of the lens used for focusing. The smallest focal spot size that could be achieved with the examined lens employed as a spherical reflector was found to be about 1 μm. By comparison to the idealized resolution a degradation of about a factor of 2 can be deduced. This limits the actual quality of the acoustic focus.

  18. Building Facade Documentation Using Laser Scanning and Photogrammetry and Data Implementation Into Bim

    NASA Astrophysics Data System (ADS)

    Faltýnová, M.; Matoušková, E.; Šedina, J.; Pavelka, K.

    2016-06-01

    A project started last year called MORE-CONNECT, which focuses on the renovation of buildings (especially building facades) using prefabricated elements. The aim of this project is to create a competitive solution consisting of a technology and processes which enable fast, cost-effective renovation with minimal difficulties to inhabitants. Significant cost savings in renovation costs lies in the usage of prefabricated elements and the reduction of construction works on site. The precision of the prefabricated element depends on the precision of the construction, project and building documentation. This article offers an overview of the possible methods for building documentation and spatial data transfer into BIM (Building Information Modelling) software. The description of methods focuses on laser scanning and photogrammetry (including RPAS based), its advantages, disadvantages and limitations according to the documented building, level of renovation, situation on site etc. The next part involves spatial data transfer into BIM software. A proposed solution is tested in a case study.

  19. Spatiotemporal Rank Filtering Improves Image Quality Compared to Frame Averaging in 2-Photon Laser Scanning Microscopy.

    PubMed

    Pinkard, Henry; Corbin, Kaitlin; Krummel, Matthew F

    2016-01-01

    Live imaging of biological specimens using optical microscopy is limited by tradeoffs between spatial and temporal resolution, depth into intact samples, and phototoxicity. Two-photon laser scanning microscopy (2P-LSM), the gold standard for imaging turbid samples in vivo, has conventionally constructed images with sufficient signal-to-noise ratio (SNR) generated by sequential raster scans of the focal plane and temporal integration of the collected signals. Here, we describe spatiotemporal rank filtering, a nonlinear alternative to temporal integration, which makes more efficient use of collected photons by selectively reducing noise in 2P-LSM images during acquisition. This results in much higher SNR while preserving image edges and fine details. Practically, this allows for at least a four fold decrease in collection times, a substantial improvement for time-course imaging in biological systems. PMID:26938064

  20. Evaluation of the Cytotoxic Behavior of Fungal Extracellular Synthesized Ag Nanoparticles Using Confocal Laser Scanning Microscope.

    PubMed

    Salaheldin, Taher A; Husseiny, Sherif M; Al-Enizi, Abdullah M; Elzatahry, Ahmed; Cowley, Alan H

    2016-01-01

    Silver nanoparticles have been synthesized by subjecting a reaction medium to a Fusarium oxysporum biomass at 28 °C for 96 h. The biosynthesized Ag nanoparticles were characterized on the basis of their anticipated peak at 405 nm using UV-Vis-NIR spectroscopy. Structural confirmation was evident from the characteristic X-ray diffraction (XRD) pattern, high-resolution transmission electron Microscopy (HRTEM) and the particle size analyzer. The Ag nanoparticles were of dimension 40 ± 5 nm and spherical in shape. The study mainly focused on using the confocal laser scanning microscope (CLSM) to examine the cytotoxic activities of fungal synthesized Ag nanoparticles on a human breast carcinoma cell line MCF7 cell, which featured remarkable vacuolation, thus indicating a potent cytotoxic activity. PMID:26950118

  1. Model Based Viewpoint Planning for Terrestrial Laser Scanning from AN Economic Perspective

    NASA Astrophysics Data System (ADS)

    Wujanz, D.; Neitzel, F.

    2016-06-01

    Despite the enormous popularity of terrestrial laser scanners in the field of Geodesy, economic aspects in the context of data acquisition are mostly considered intuitively. In contrast to established acquisition techniques, such as tacheometry and photogrammetry, optimisation of the acquisition configuration cannot be conducted based on assumed object coordinates, as these would change in dependence to the chosen viewpoint. Instead, a combinatorial viewpoint planning algorithm is proposed that uses a given 3D-model as an input and simulates laser scans based on predefined viewpoints. The method determines a suitably small subset of viewpoints from which the sampled object surface is preferably large. An extension of the basic algorithm is proposed that only considers subsets of viewpoints that can be registered to a common dataset. After exemplification of the method, the expected acquisition time in the field is estimated based on computed viewpoint plans.

  2. Object shape classification and scene shape representation for three-dimensional laser scanned outdoor data

    NASA Astrophysics Data System (ADS)

    Ning, Xiaojuan; Wang, Yinghui; Zhang, Xiaopeng

    2013-02-01

    Shape analysis of a three-dimensional (3-D) scene is an important issue and could be widely used for various applications: city planning, robot navigation, virtual tourism, etc. We introduce an approach for understanding the primitive shape of the scene to reveal the semantic scene shape structure and represent the scene using shape elements. The scene objects are labeled and recognized using the geometric and semantic features for each cluster, which is based on the knowledge of scene. Furthermore, the object in scene with a different primitive shape could also be classified and fitted using the Gaussian map of the segmented scene. We demonstrate the presented approach on several complex scenes from laser scanning. According to the experimental result, the proposed method can accurately represent the geometric structure of the 3-D scene.

  3. Geometric validation of a mobile laser scanning system for urban applications

    NASA Astrophysics Data System (ADS)

    Guan, Haiyan; Li, Jonathan; Yu, Yongtao; Liu, Yan

    2016-03-01

    Mobile laser scanning (MLS) technologies have been actively studied and implemented over the past decade, as their application fields are rapidly expanding and extending beyond conventional topographic mapping. Trimble's MX-8, as one of the MLS systems in the current market, generates rich survey-grade laser and image data for urban surveying. The objective of this study is to evaluate whether Trimble MX-8 MLS data satisfies the accuracy requirements of urban surveying. According to the formula of geo-referencing, accuracies of navigation solution and laser scanner determines the accuracy of the collected LiDAR point clouds. Two test sites were selected to test the performance of Trimble MX-8. Those extensive tests confirm that Trimble MX-8 offers a very promising tool to survey complex urban areas.

  4. Analysis of the melanin distribution in different ethnic groups by in vivo laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Antoniou, C.; Lademann, J.; Richter, H.; Astner, S.; Patzelt, A.; Zastrow, L.; Sterry, W.; Koch, S.

    2009-05-01

    The aim of this study was to determine whether Laser scanning confocal microscopy (LSM) is able to visualize differences in melanin content and distribution in different Skin Phototypes. The investigations were carried out on six healthy volunteers with Skin Phototypes II, IV, and VI. Representative skin samples of Skin Phototypes II, V, and VI were obtained for histological analysis from remaining tissue of skin grafts and were used for LSM-pathologic correlation. LSM evaluation showed significant differences in melanin distribution in Skin Phototypes II, IV, and VI, respectively. Based on the differences in overall reflectivity and image brightness, a visual evaluation scheme showed increasing brightness of the basal and suprabasal layers with increasing Skin Phototypes. The findings correlated well with histological analysis. The results demonstrate that LSM may serve as a promising adjunctive tool for real time assessment of melanin content and distribution in human skin, with numerous clinical applications and therapeutic and preventive implications.

  5. Using Mobile Laser Scanning Data for Features Extraction of High Accuracy Driving Maps

    NASA Astrophysics Data System (ADS)

    Yang, Bisheng; Liu, Yuan; Liang, Fuxun; Dong, Zhen

    2016-06-01

    High Accuracy Driving Maps (HADMs) are the core component of Intelligent Drive Assistant Systems (IDAS), which can effectively reduce the traffic accidents due to human error and provide more comfortable driving experiences. Vehicle-based mobile laser scanning (MLS) systems provide an efficient solution to rapidly capture three-dimensional (3D) point clouds of road environments with high flexibility and precision. This paper proposes a novel method to extract road features (e.g., road surfaces, road boundaries, road markings, buildings, guardrails, street lamps, traffic signs, roadside-trees, power lines, vehicles and so on) for HADMs in highway environment. Quantitative evaluations show that the proposed algorithm attains an average precision and recall in terms of 90.6% and 91.2% in extracting road features. Results demonstrate the efficiencies and feasibilities of the proposed method for extraction of road features for HADMs.

  6. Semi-Automatic Road/Pavement Modeling using Mobile Laser Scanning

    NASA Astrophysics Data System (ADS)

    Hervieu, A.; Soheilian, B.

    2013-10-01

    Scene analysis, in urban environments, deals with street modeling and understanding. A street mainly consists of roadways, pavements (i.e., walking areas), facades, still and moving obstacles. In this paper, we investigate the surface modeling of roadways and pavements using LIDAR data acquired by a mobile laser scanning (MLS) system. First, road border detection is considered. A system recognizing curbs and curb ramps while reconstructing the missing information in case of occlusion is presented. A user interface scheme is also described, providing an effective tool for semi-automatic processing of large amount of data. Then, based upon road edge information, a process that reconstructs surfaces of roads and pavements has been developed, providing a centimetric precision while reconstructing missing information. This system hence provides an important knowledge of the street, that may open perspectives in various domains such as path planning or road maintenance.

  7. A laser-scanning endoscope based on polysilicon micromachined mirrors with enhanced attributes

    NASA Astrophysics Data System (ADS)

    George, Markus; Albrecht, Hansjoerg; Schurr, Marc O.; Papageorgas, Panagiotis G.; Hofmann, Ulrich; Maroulis, Dimitris; Depeursinge, Christian D.; Iakkovidis, Dimitris; Theofanous, Nikiforos; Menciassi, Arianna

    2003-10-01

    A miniaturized laser scanning endoscope is presented which makes use of three lasers to illuminate a sample with a red, a green and a blue wavelength simultaneously. Scattered light from the sample is descanned and chromatically separated into the three channels for detection and postprocessing to compose a color image. The scanning subsystem consists of two micro-electro-mechanical mirrors suitable for mass production. The endoscope head can be assembled fast and at low cost. A resolution of the order of 16 lines per mm is achieved for a working distance common in endoscopy. Considerations of the system design include the operation of the mico mirrors, the filtering of reflected light by using polarization effects and a strategy to cope with color metamery. An expert system based on a neural network was found able to analyze endoscopic images to identify suspicious lesions.

  8. Investigation of phosphatidylcholine enhancing FITC-insulin across buccal mucosa by confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Tian, Weiqun; Su, Li; Zeng, Shaoqun; Luo, Qingming; Gao, Qiuhua; Xu, Huibi

    2002-04-01

    The aim was to characterize the transport of fluorescein isothiocyanate (FITC)-labeled dextran and insulin with different resoluble compounds for peptides and proteins through buccal mucosa. The penetration rate of insulin molecules through porcine buccal mucosa (a nonkeratinized epithelium, comparable to human buccal mucosa) was investigated by measuring transbuccal fluxes and by analyzing the distribution of the fluorescent probe in the rabbit buccal mucosa epithelium, using confocal laser scanning microscopy for visualizing permeation pathways. The confocal images of the distribution pattern of FITC-dextran and FITC-insulin showed that the paracellular route is the major pathway of FITC-dextran through buccal mucosa epithelium, the intra-cellular route is the major pathway of FITC-insulin through buccal mucosa epithelium. The permeation rate can be increased by co-administration of soybean phosphatidylcholine (SPC).

  9. Low temperature laser scanning microscopy of a superconducting radio-frequency cavity

    NASA Astrophysics Data System (ADS)

    Ciovati, G.; Anlage, Steven M.; Baldwin, C.; Cheng, G.; Flood, R.; Jordan, K.; Kneisel, P.; Morrone, M.; Nemes, G.; Turlington, L.; Wang, H.; Wilson, K.; Zhang, S.

    2012-03-01

    An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about 2.4 mm and surface resistance resolution of ˜1 μΩ at 3.3 GHz. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in detail in this contribution.

  10. Low cost and compact nonlinear (SHG/TPE) laser scanning endoscope for bio-medical application

    NASA Astrophysics Data System (ADS)

    Liu, Jiayun; Lim, Ken Choong; Li, Hao; Seck, Hon Luen; Yu, Xia; Kok, Shaw Wei; Zhang, Ying

    2015-03-01

    Two-photon fluorescence (TPE) and second harmonic generation (SHG) can been used to extract biological information from tissues at the molecular level, which is blind to traditional microscopes. Through these two image contrast mechanisms, a nonlinear laser scanning endoscope (NLSE) is able to image tissue cells and the extra cellular matrix (ECM) through a special fiber and miniaturized scanner without the requirement of poisonous chemical staining. Therefore, NLSE reserves high potential for in-vivo pathological study and disease diagnosis. However, the high cost and bulky size of a NLSE system has become one of the major issues preventing this technology from practical clinical operation. In this paper, we report a fiber laser based multi-modality NLSE system with compact size and low cost, ideal for in-vivo applications in clinical environments. The demonstration of the developed NLSE nonlinear imaging capability on different bio-structures in liver, retina and skin are also presented.

  11. Large-field-of-view laser-scanning OR-PAM using a fibre optic sensor

    NASA Astrophysics Data System (ADS)

    Allen, T. J.; Zhang, E.; Beard, P. C.

    2015-03-01

    Laser-Scanning-Optical-Resolution Photoacoustic Microscopy (LSOR-PAM) requires an ultrasound detector with a low noise equivalent pressure (NEP) and a large angular detection aperture in order to image a large field of view (FOV). It is however challenging to meet these requirements when using piezoelectric receivers since using a small sensing element size (<100μm) in order to achieve a large angular detection aperture will inevitability reduce the sensitivity of the detector as it scales with decreasing element size. Fibre optic ultrasound sensors based on a Fabry Perot cavity do not suffer from this limitation and can provide high detection sensitivity (NEP<0.1kPa over a 20 MHz measurement bandwidth) with a large angular detection aperture due to their small active element size (~10μm). A LSOR-PAM system was developed and combined with this type of fibre optic ultrasound sensor. A set of phantom studies were undertaken. The first study demonstrated that a high resolution image over a large field of view (Ø11mm) could be obtained with a sampledetector separation of only 1.6mm. In the second study, a 12μm diameter tube filled with methylene blue whose absorption coefficient was similar to that of blood was visualised demonstrating that the fibre optic sensor could provide sufficient SNR for in-vivo microvascular OR-PAM imaging. These preliminary results suggest that the fibre optic sensor has the potential to outperform piezoelectric detectors for Laser-Scanning Optical Resolution Photoacoustic Microscopy (LSOR-PAM).

  12. Automatic Feature Detection, Description and Matching from Mobile Laser Scanning Data and Aerial Imagery

    NASA Astrophysics Data System (ADS)

    Hussnain, Zille; Oude Elberink, Sander; Vosselman, George

    2016-06-01

    In mobile laser scanning systems, the platform's position is measured by GNSS and IMU, which is often not reliable in urban areas. Consequently, derived Mobile Laser Scanning Point Cloud (MLSPC) lacks expected positioning reliability and accuracy. Many of the current solutions are either semi-automatic or unable to achieve pixel level accuracy. We propose an automatic feature extraction method which involves utilizing corresponding aerial images as a reference data set. The proposed method comprise three steps; image feature detection, description and matching between corresponding patches of nadir aerial and MLSPC ortho images. In the data pre-processing step the MLSPC is patch-wise cropped and converted to ortho images. Furthermore, each aerial image patch covering the area of the corresponding MLSPC patch is also cropped from the aerial image. For feature detection, we implemented an adaptive variant of Harris-operator to automatically detect corner feature points on the vertices of road markings. In feature description phase, we used the LATCH binary descriptor, which is robust to data from different sensors. For descriptor matching, we developed an outlier filtering technique, which exploits the arrangements of relative Euclidean-distances and angles between corresponding sets of feature points. We found that the positioning accuracy of the computed correspondence has achieved the pixel level accuracy, where the image resolution is 12cm. Furthermore, the developed approach is reliable when enough road markings are available in the data sets. We conclude that, in urban areas, the developed approach can reliably extract features necessary to improve the MLSPC accuracy to pixel level.

  13. Street-side vehicle detection, classification and change detection using mobile laser scanning data

    NASA Astrophysics Data System (ADS)

    Xiao, Wen; Vallet, Bruno; Schindler, Konrad; Paparoditis, Nicolas

    2016-04-01

    Statistics on street-side car parks, e.g. occupancy rates, parked vehicle types, parking durations, are of great importance for urban planning and policy making. Related studies, e.g. vehicle detection and classification, mostly focus on static images or video. Whereas mobile laser scanning (MLS) systems are increasingly utilized for urban street environment perception due to their direct 3D information acquisition, high accuracy and movability. In this paper, we design a complete system for car park monitoring, including vehicle recognition, localization, classification and change detection, from laser scanning point clouds. The experimental data are acquired by an MLS system using high frequency laser scanner which scans the streets vertically along the system's moving trajectory. The point clouds are firstly classified as ground, building façade, and street objects which are then segmented using state-of-the-art methods. Each segment is treated as an object hypothesis, and its geometric features are extracted. Moreover, a deformable vehicle model is fitted to each object. By fitting an explicit model to the vehicle points, detailed information, such as precise position and orientation, can be obtained. The model parameters are also treated as vehicle features. Together with the geometric features, they are applied to a supervised learning procedure for vehicle or non-vehicle recognition. The classes of detected vehicles are also investigated. Whether vehicles have changed across two datasets acquired at different times is detected to estimate the durations. Here, vehicles are trained pair-wisely. Two same or different vehicles are paired up as training samples. As a result, the vehicle recognition, classification and change detection accuracies are 95.9%, 86.0% and 98.7%, respectively. Vehicle modelling improves not only the recognition rate, but also the localization precision compared to bounding boxes.

  14. Lateral resolution improvement of laser-scanning imaging for nano defects detection

    NASA Astrophysics Data System (ADS)

    Yokozeki, Hiroki; Kudo, Ryota; Takahashi, Satoru; Takamasu, Kiyoshi

    2014-08-01

    Demand for higher efficiency in the semiconductor manufacturing industry is continually increasing. In particular, nano defects measurement on patterned or bare Si semiconductor wafer surfaces is an important quality control factor for realizing high productivity and reliability of semiconductor device fabrication. Optical methods and electron beam methods are conventionally used for the inspection of semiconductor wafers. Because they are nondestructive and suitable for high-throughput inspection, optical methods are preferable to electron beam methods such as scanning electron microscopy, transmission electron microscopy, and so on. However, optical methods generally have an essential disadvantage about lateral spatial resolution than electron beam methods, because of the diffraction limit depending on the optical wavelength. In this research, we aim to develop a novel laser-scanning imaging method that can be applied to nano-/micro manufacturing processes such as semiconductor wafer surface inspection to allow lateral spatial super-resolution imaging with resolution beyond the diffraction limit. In our proposed method, instead of detecting the light intensity value from the beam spot on the inspection surface, the light intensity distribution, which is formed with infinity corrected optical system, coming from the beam spot on the inspection surface is detected. In addition, nano scale shifts in the beam spot are applied for laser spot scanning using a conventional laser-scanning method in which the spots are shifted at about a 100 nm pitch. By detecting multiple light intensity distributions due to the nano scale shifts, a super-resolution image reconstruction with resolution beyond the diffraction limit can be expected. In order to verify the feasibility of the proposed method, several numerical simulations were carried out.

  15. Feature-Based Laser Scan Matching and Its Application for Indoor Mapping.

    PubMed

    Li, Jiayuan; Zhong, Ruofei; Hu, Qingwu; Ai, Mingyao

    2016-01-01

    Scan matching, an approach to recover the relative position and orientation of two laser scans, is a very important technique for indoor positioning and indoor modeling. The iterative closest point (ICP) algorithm and its variants are the most well-known techniques for such a problem. However, ICP algorithms rely highly on the initial guess of the relative transformation, which will reduce its power for practical applications. In this paper, an initial-free 2D laser scan matching method based on point and line features is proposed. We carefully design a framework for the detection of point and line feature correspondences. First, distinct feature points are detected based on an extended 1D SIFT, and line features are extracted via a modified Split-and-Merge algorithm. In this stage, we also give an effective strategy for discarding unreliable features. The point and line features are then described by a distance histogram; the pairs achieving best matching scores are accepted as potential correct correspondences. The histogram cluster technique is adapted to filter outliers and provide an accurate initial value of the rigid transformation. We also proposed a new relative pose estimation method that is robust to outliers. We use the lq-norm (0 < q < 1) metric in this approach, in contrast to classic optimization methods whose cost function is based on the l₂-norm of residuals. Extensive experiments on real data demonstrate that the proposed method is almost as accurate as ICPs and is initial free. We also show that our scan matching method can be integrated into a simultaneous localization and mapping (SLAM) system for indoor mapping. PMID:27517932

  16. Registration of Laser Scanning Point Clouds and Aerial Images Using either Artificial or Natural Tie Features

    NASA Astrophysics Data System (ADS)

    Rönnholm, P.; Haggrén, H.

    2012-07-01

    Integration of laser scanning data and photographs is an excellent combination regarding both redundancy and complementary. Applications of integration vary from sensor and data calibration to advanced classification and scene understanding. In this research, only airborne laser scanning and aerial images are considered. Currently, the initial registration is solved using direct orientation sensors GPS and inertial measurements. However, the accuracy is not usually sufficient for reliable integration of data sets, and thus the initial registration needs to be improved. A registration of data from different sources requires searching and measuring of accurate tie features. Usually, points, lines or planes are preferred as tie features. Therefore, the majority of resent methods rely highly on artificial objects, such as buildings, targets or road paintings. However, in many areas no such objects are available. For example in forestry areas, it would be advantageous to be able to improve registration between laser data and images without making additional ground measurements. Therefore, there is a need to solve registration using only natural features, such as vegetation and ground surfaces. Using vegetation as tie features is challenging, because the shape and even location of vegetation can change because of wind, for example. The aim of this article was to compare registration accuracies derived by using either artificial or natural tie features. The test area included urban objects as well as trees and other vegetation. In this area, two registrations were performed, firstly, using mainly built objects and, secondly, using only vegetation and ground surface. The registrations were solved applying the interactive orientation method. As a result, using artificial tie features leaded to a successful registration in all directions of the coordinate system axes. In the case of using natural tie features, however, the detection of correct heights was difficult causing

  17. Keypoint-based 4-Points Congruent Sets - Automated marker-less registration of laser scans

    NASA Astrophysics Data System (ADS)

    Theiler, Pascal Willy; Wegner, Jan Dirk; Schindler, Konrad

    2014-10-01

    We propose a method to automatically register two point clouds acquired with a terrestrial laser scanner without placing any markers in the scene. What makes this task challenging are the strongly varying point densities caused by the line-of-sight measurement principle, and the huge amount of data. The first property leads to low point densities in potential overlap areas with scans taken from different viewpoints while the latter calls for highly efficient methods in terms of runtime and memory requirements. A crucial yet largely unsolved step is the initial coarse alignment of two scans without any simplifying assumptions, that is, point clouds are given in arbitrary local coordinates and no knowledge about their relative orientation is available. Once coarse alignment has been solved, scans can easily be fine-registered with standard methods like least-squares surface or Iterative Closest Point matching. In order to drastically thin out the original point clouds while retaining characteristic features, we resort to extracting 3D keypoints. Such clouds of keypoints, which can be viewed as a sparse but nevertheless discriminative representation of the original scans, are then used as input to a very efficient matching method originally developed in computer graphics, called 4-Points Congruent Sets (4PCS) algorithm. We adapt the 4PCS matching approach to better suit the characteristics of laser scans. The resulting Keypoint-based 4-Points Congruent Sets (K-4PCS) method is extensively evaluated on challenging indoor and outdoor scans. Beyond the evaluation on real terrestrial laser scans, we also perform experiments with simulated indoor scenes, paying particular attention to the sensitivity of the approach with respect to highly symmetric scenes.

  18. Evaluation of penetration depth of 2% chlorhexidine digluconate into root dentinal tubules using confocal laser scanning microscope

    PubMed Central

    Latha, Jothi; Velmurugan, Natanasabapathy

    2015-01-01

    Objectives This study evaluated the penetration depth of 2% chlorhexidine digluconate (CHX) into root dentinal tubules and the influence of passive ultrasonic irrigation (PUI) using a confocal laser scanning microscope (CLSM). Materials and Methods Twenty freshly extracted anterior teeth were decoronated and instrumented using Mtwo rotary files up to size 40, 4% taper. The samples were randomly divided into two groups (n = 10), that is, conventional syringe irrigation (CSI) and PUI. CHX was mixed with Rhodamine B dye and was used as the final irrigant. The teeth were sectioned at coronal, middle and apical levels and viewed under CLSM to record the penetration depth of CHX. The data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests. Results The mean penetration depths of 2% CHX in coronal, middle and apical thirds were 138 µm, 80 µm and 44 µm in CSI group, respectively, whereas the mean penetration depths were 209 µm, 138 µm and 72 µm respectively in PUI group. Statistically significant difference was present between CSI group and PUI group at all three levels (p < 0.01 for coronal third and p < 0.001 for middle and apical thirds). On intragroup analysis, both groups showed statistically significant difference among three levels (p < 0.001). Conclusions Penetration depth of 2% CHX into root dentinal tubules is deeper in coronal third when compared to middle and apical third. PUI aided in deeper penetration of 2% CHX into dentinal tubules when compared to conventional syringe irrigation at all three levels. PMID:25984477

  19. Terrestrial laser scanning and pin meter measurements for erosion and roughness assessment in boreal peatland forest ditches

    NASA Astrophysics Data System (ADS)

    Stenberg, Leena; Tuukkanen, Tapio; Finér, Leena; Marttila, Hannu; Piirainen, Sirpa; Kløve, Bjørn; Koivusalo, Harri

    2016-04-01

    Drainage and the maintenance of drainage ditches in peatland forests increase erosion and sediment load reducing water quality downstream. The understanding of the sediment source area processes requires reliable methods for topographical change detection in the peatland forest ditches. The objective of this study was to quantify erosion and changes in surface roughness with two different methods: terrestrial laser scanning (TLS) and manual pin meter measurements. Two newly cleaned boreal peatland forest ditches were studied, one peat ditch and one with exposed till soil under the thin peat layer. The topographies of a 4-meter-long section of the ditches were measured sequentially during the 11-20 months study period. In the ditch with thin peat layer, erosion estimates were quite similar with both methods. However, in the peat ditch the erosion measured with the pin meter considerably exceeded the results provided by TLS. Surface roughness indicated by the TLS data was greater than the surface roughness calculated from the pin meter data. According to both methods, surface roughness increased more at the ditch with thin peat layer. Both methods could be adopted to measure erosion and surface roughness in peatland forest conditions. However, the methods had difficulties to distinguish the bed of the peat ditch. TLS encountered problems to detect dark peat soil bed under shallow layer of humic ditch water resulting in no-data areas at the bed of the ditch. Pin meter device was able to measure under the water but the soft peat bed increased the uncertainty of the measurements.

  20. Adhesion of rice flour-based batter to chicken drumsticks evaluated by laser scanning confocal microscopy and texture analysis.

    PubMed

    Mukprasirt, A; Herald, T J; Boyle, D L; Rausch, K D

    2000-09-01

    The convenience and appeal of battered or breaded products have resulted in a sales increase of 100% since 1980. Because of the rapid growth of the Asian-American population and increasing consumption of rice and rice products, rice flour is a logical alternative for wheat flour in traditional batter formulation. The effects of ingredients used in rice flour-based batters on adhesion characteristic for deep-fat fried chicken drumsticks were studied by laser scanning confocal microscopy (LSCM) and texture analysis. Raw chicken drumsticks were predusted with egg albumin powder before dipping into batters prepared from combinations of rice flour, yellow corn flour, oxidized cornstarch, methylcellulose, or xanthan gum. The drumsticks were fried at 175+/-5 C until the internal temperature reached at least 71 C. For LSCM, samples were fixed overnight and were sectioned by vibratome (200 microm) before viewing. Batter adhesion was determined using an attachment specifically designed for chicken drumsticks. Microstructural analysis showed that batter formulated with a 50:50 mixture of rice and corn flours adhered better to drumsticks than batter with other rice flour ratios. Xanthan gum (0.2%) or methylcellulose (0.3%) alone had poor adhesion to chicken skin. However, when combined with other ingredients, xanthan gum increased the amount of batter pick-up before frying by increasing viscosity. Egg albumin significantly facilitated batter adhesion. The results from texture analysis supported the microstructural studies. As rice flour ratio increased from 50 to 70%, the binding force decreased. Rice flour showed potential as an alternative to wheat flour for batter formulas when the appropriate levels of oxidized starch, xanthan gum, and methylcellulose were included in the formulation. PMID:11020085

  1. Accuracy in estimation of timber assortments and stem distribution - A comparison of airborne and terrestrial laser scanning techniques

    NASA Astrophysics Data System (ADS)

    Kankare, Ville; Vauhkonen, Jari; Tanhuanpää, Topi; Holopainen, Markus; Vastaranta, Mikko; Joensuu, Marianna; Krooks, Anssi; Hyyppä, Juha; Hyyppä, Hannu; Alho, Petteri; Viitala, Risto

    2014-11-01

    Detailed information about timber assortments and diameter distributions is required in forest management. Forest owners can make better decisions concerning the timing of timber sales and forest companies can utilize more detailed information to optimize their wood supply chain from forest to factory. The objective here was to compare the accuracies of high-density laser scanning techniques for the estimation of tree-level diameter distribution and timber assortments. We also introduce a method that utilizes a combination of airborne and terrestrial laser scanning in timber assortment estimation. The study was conducted in Evo, Finland. Harvester measurements were used as a reference for 144 trees within a single clear-cut stand. The results showed that accurate tree-level timber assortments and diameter distributions can be obtained, using terrestrial laser scanning (TLS) or a combination of TLS and airborne laser scanning (ALS). Saw log volumes were estimated with higher accuracy than pulpwood volumes. The saw log volumes were estimated with relative root-mean-squared errors of 17.5% and 16.8% with TLS and a combination of TLS and ALS, respectively. The respective accuracies for pulpwood were 60.1% and 59.3%. The differences in the bucking method used also caused some large errors. In addition, tree quality factors highly affected the bucking accuracy, especially with pulpwood volume.

  2. Correcting spherical aberrations in a biospecimen using a transmissive liquid crystal device in two-photon excitation laser scanning microscopy.

    PubMed

    Tanabe, Ayano; Hibi, Terumasa; Ipponjima, Sari; Matsumoto, Kenji; Yokoyama, Masafumi; Kurihara, Makoto; Hashimoto, Nobuyuki; Nemoto, Tomomi

    2015-10-01

    Two-photon excitation laser scanning microscopy has enabled the visualization of deep regions in a biospecimen. However, refractive-index mismatches in the optical path cause spherical aberrations that degrade spatial resolution and the fluorescence signal, especially during observation at deeper regions. Recently, we developed transmissive liquid-crystal devices for correcting spherical aberration without changing the basic design of the optical path in a conventional laser scanning microscope. In this study, the device was inserted in front of the objective lens and supplied with the appropriate voltage according to the observation depth. First, we evaluated the device by observing fluorescent beads in single- and two-photon excitation laser scanning microscopes. Using a 25× water-immersion objective lens with a numerical aperture of 1.1 and a sample with a refractive index of 1.38, the device recovered the spatial resolution and the fluorescence signal degraded within a depth of 0.6 mm. Finally, we implemented the device for observation of a mouse brain slice in a two-photon excitation laser scanning microscope. An optical clearing reagent with a refractive index of 1.42 rendered the fixed mouse brain transparent. The device improved the spatial resolution and the yellow fluorescent protein signal within a depth of 0-0.54 mm. PMID:26244766

  3. Correcting spherical aberrations in a biospecimen using a transmissive liquid crystal device in two-photon excitation laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Tanabe, Ayano; Hibi, Terumasa; Ipponjima, Sari; Matsumoto, Kenji; Yokoyama, Masafumi; Kurihara, Makoto; Hashimoto, Nobuyuki; Nemoto, Tomomi

    2015-10-01

    Two-photon excitation laser scanning microscopy has enabled the visualization of deep regions in a biospecimen. However, refractive-index mismatches in the optical path cause spherical aberrations that degrade spatial resolution and the fluorescence signal, especially during observation at deeper regions. Recently, we developed transmissive liquid-crystal devices for correcting spherical aberration without changing the basic design of the optical path in a conventional laser scanning microscope. In this study, the device was inserted in front of the objective lens and supplied with the appropriate voltage according to the observation depth. First, we evaluated the device by observing fluorescent beads in single- and two-photon excitation laser scanning microscopes. Using a 25× water-immersion objective lens with a numerical aperture of 1.1 and a sample with a refractive index of 1.38, the device recovered the spatial resolution and the fluorescence signal degraded within a depth of ±0.6 mm. Finally, we implemented the device for observation of a mouse brain slice in a two-photon excitation laser scanning microscope. An optical clearing reagent with a refractive index of 1.42 rendered the fixed mouse brain transparent. The device improved the spatial resolution and the yellow fluorescent protein signal within a depth of 0-0.54 mm.

  4. Development of variable-rate sprayer with laser scanning sensor to synchronize spray outputs to tree structures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Efficient and effective precision spray equipment and strategies have been constantly demanded to reduce pesticide use in tree crop productions. An experimental variable-rate air-assisted sprayer implemented with a high-speed laser scanning sensor was developed to control the spray output of individ...

  5. The illuminating role of laser scanning digital elevation models in precision agriculture experimental designs - an agro-ecology perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laser scanning data streams, when linked with multi-spectral, hyperspectral, apparent soil electro-conductivity (ECa), or other kinds of geo-referenced data streams, aid in the creation of maps that allow useful applications in agricultural systems. These combinations of georeferenced information p...

  6. USE OF MULTIPHOTON LASER SCANNING MICROSCOPY TO IMAGE BENZO[A]PYRENE AND METABOLITES IN FISH EGGS

    EPA Science Inventory

    Multiphoton laser scanning microscopy (MPLSM) is a promising tool to study the tissue distribution of environmental chemical contaminants during fish early life stages. One such chemical for which this is possible is benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon that a...

  7. Airborne laser scanning of forest resources: An overview of research in Italy as a commentary case study

    NASA Astrophysics Data System (ADS)

    Montaghi, Alessandro; Corona, Piermaria; Dalponte, Michele; Gianelle, Damiano; Chirici, Gherardo; Olsson, Håkan

    2013-08-01

    This article reviews the recent literature concerning airborne laser scanning for forestry purposes in Italy, and presents the current methodologies used to extract forest characteristics from discrete return ALS (Airborne Laser Scanning) data. Increasing interest in ALS data is currently being shown, especially for remote sensing-based forest inventories in Italy; the driving force for this interest is the possibility of reducing costs and providing more accurate and efficient estimation of forest characteristics. This review covers a period of approximately ten years, from the first application of laser scanning for forestry purposes in 2003 to the present day, and shows that there are numerous ongoing research activities which use these technologies for the assessment of forest attributes (e.g., number of trees, mean tree height, stem volume) and ecological issues (e.g., gap identification, fuel model detection). The basic approaches - such as single tree detection and area-based modeling - have been widely examined and commented in order to explore the trend of methods in these technologies, including their applicability and performance. Finally this paper outlines and comments some of the common problems encountered in operational use of laser scanning in Italy, offering potentially useful guidelines and solutions for other countries with similar conditions, under a rather variable environmental framework comprising Alpine, temperate and Mediterranean forest ecosystems.

  8. The reproducibility of the head position for a laser scan using a novel morphometric analysis for orthognathic surgery.

    PubMed

    Soncul, M; Bamber, M A

    2000-04-01

    The aim of this study was to evaluate the reproducibility of the head position for a three-dimensional soft tissue laser scan (lasergraph) using thin-plate splines, for orthognathic surgery planning and follow-up. 60 laser scans of five subjects (12 scans per subject) were obtained at specified intervals. The head was positioned in the lateral view using a spirit level, an engineering device for setting horizontal surfaces, to adjust the Frankfort horizontal plane parallel to the ground. The projection of a narrow beam of longitudinal laser light was used to adjust the axial plane for the frontal view. These scanned images (lasergraphs) were digitised and the co-ordinates of the landmarks recorded. The digitised laser scans were compared using thin-plate splines analysis. The mean difference between the scans due to variations in head position was 0.0135 +/- 0.0109 g x cm2/ sec2 in the lateral view and 0.0090 +/- 0.0054 g x cm2/sec2 in the frontal view. This represents an overall distortion error of less than 2% when following up the surgical change of a typical bimaxillary osteotomy case with 6 mm maxillary advancement and 3 mm mandibular set-back. It is concluded that facial laser scans (lasergraphs) with the Frankfort horizontal plane set using a head rest and spirit level, and the axial plane set using projection of a vertical laser light on the facial midline, are highly reproducible. PMID:10833142

  9. USE OF MULTIPHOTON LASER SCANNING MICROSCOPY TO IMAGE BENZO[A]PYRENE AND METABOLITES IN FISH EARLY LIFE STAGES

    EPA Science Inventory

    Multiphoton laser scanning micrsocopy holds promise as a tool to study the tissue distribution of environmental chemical contaminants during fish early life stage development. One such chemical for which this is possible is benzo[a]pyrene (BaP), a polyaromatic hydrocarbon that a...

  10. Development, Calibration and Evaluation of a Portable and Direct Georeferenced Laser Scanning System for Kinematic 3D Mapping

    NASA Astrophysics Data System (ADS)

    Heinz, Erik; Eling, Christian; Wieland, Markus; Klingbeil, Lasse; Kuhlmann, Heiner

    2015-12-01

    In recent years, kinematic laser scanning has become increasingly popular because it offers many benefits compared to static laser scanning. The advantages include both saving of time in the georeferencing and a more favorable scanning geometry. Often mobile laser scanning systems are installed on wheeled platforms, which may not reach all parts of the object. Hence, there is an interest in the development of portable systems, which remain operational even in inaccessible areas. The development of such a portable laser scanning system is presented in this paper. It consists of a lightweight direct georeferencing unit for the position and attitude determination and a small low-cost 2D laser scanner. This setup provides advantages over existing portable systems that employ heavy and expensive 3D laser scanners in a profiling mode. A special emphasis is placed on the system calibration, i. e. the determination of the transformation between the coordinate frames of the direct georeferencing unit and the 2D laser scanner. To this end, a calibration field is used, which consists of differently orientated georeferenced planar surfaces, leading to estimates for the lever arms and boresight angles with an accuracy of mm and one-tenth of a degree. Finally, point clouds of the mobile laser scanning system are compared with georeferenced point clouds of a high-precision 3D laser scanner. Accordingly, the accuracy of the system is in the order of cm to dm. This is in good agreement with the expected accuracy, which has been derived from the error propagation of previously estimated variance components.

  11. Linking water surface roughness to velocity patterns using terrestrial laser scanning and acoustic doppler velocimetry

    NASA Astrophysics Data System (ADS)

    Heritage, George; Milan, David; Entwistle, Neil

    2010-05-01

    There are well established links between water surface characteristics and hydraulics. Biotope identification is currently an important part of the River Habitat Survey in England and Wales. Their differentiation is based upon recognition of a family of flow features exhibited on the water surface. Variability in this water surface ‘roughness' is dependent upon the interaction of flow with boundary roughness and flow depth. Past research that has attempted to differentiate biotopes based upon differences in Froude number (Fr) and Reynolds number (Re), however this linkage has only been limited to local analysis between flow velocity, depth and roughness. Milan et al. (2010) have recently demonstrated that terrestrial laser scanning (TLS) can be applied to produce fully quantitative maps of hydraulic habitat, based upon defined water surface roughness delimeters. However the nature of the linkages between water surface roughness, flow velocity and depth are still poorly understood, particularly at the reach-scale. This study attempts to provide a full spatial picture of the links between water surface roughness, flow depth and velocity. A Sontek Acoustic Doppler Velocity Profiler (ADVP) was used to provide detailed information on vertical velocity and water depth for a 300 m reach of the gravel-bed River Wharfe, Yorkshire, UK. Simultaneous to the ADVP measurements, a Riegl LMS-Z210 TLS was used to take a series of first return scans of the water surface. Categorisation of the point cloud elevation data for the water surface was achieved through the allocation of moving window standard deviation values to a regular grid, thus defining water surface roughness. The ADVP data demonstrate gross reach-scale variation in velocity and depth linked to bedforms, and more localised spatial and temporal variation within biotope units. The ADVP data was used to produce reach-scale maps of Fr and Re. The extent to which water surface roughness defined biotopes mapped onto these

  12. Roughness of biopores and cracks in Bt-horizons by confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Leue, Martin; Gerke, Horst H.

    2016-04-01

    During preferential flow events in structured soils, the movement of water and reactive solutes is mostly restricted to larger inter-aggregate pores, cracks, and biopores. The micro-topography of such macropores in terms of pore shapes, geometry, and roughness is crucial for describing the exchange of water and solutes between macropores and the soil matrix. The objective of this study was to determine the surface roughness of intact structural surfaces from the Bt-horizon of Luvisols by confocal laser scanning microscopy. For this purpose, samples with the structural surface types including cracks with and without clay-organic coatings from Bt-horizons developed on loess and glacial till were compared. The surface roughness of these structures was calculated in terms of three parameters from selected surface regions of 0.36 mm² determined with a confocal laser scanning microscope of the type Keyence VK-X100K. These data were evaluated in terms of the root-mean-squared roughness, Rq, the curvature, Rku, and the ratio between surface area and base area, RA. Values of Rq and RA were smaller for coated as compared to uncoated cracks and earthworm burrows of the Bt-horizons from both parent materials. The results indicated that the illuviation of clayey material led to a "smoothing" of the crack surfaces, which was similar for the coarser textured till-Bt and the finer-textured loess-Bt surfaces. The roughness indicated by Rq and RA values was only slightly smaller and that indicated by Rku slightly higher for the structural surfaces from the loess as compared to those from the glacial till. These results suggest a minor importance of the parent material on the roughness of structural surfaces in the Bt-horizon. The similarity of Rq, RA, and Rku values between surfaces of earthworm burrows and uncoated cracks did not confirm an expected smoothing effect of the burrow walls by the earthworm. In contrast to burrow walls, root channels from the loess-Bt were smoother

  13. A research on snow distribution in mountainous area using airborne laser scanning

    NASA Astrophysics Data System (ADS)

    Nishihara, T.; Tanise, A.

    2015-12-01

    In snowy cold regions, the snowmelt water stored in dams in early spring meets the water demand for the summer season. Thus, snowmelt water serves as an important water resource. However, snowmelt water also can cause snowmelt floods. Therefore, it's necessary to estimate snow water equivalent in a dam basin as accurately as possible. For this reason, the dam operation offices in Hokkaido, Japan conduct snow surveys every March to estimate snow water equivalent in the dam basin. In estimating, we generally apply a relationship between elevation and snow water equivalent. But above the forest line, snow surveys are generally conducted along ridges due to the risk of avalanches or other hazards. As a result, snow water equivalent above the forest line is significantly underestimated. In this study, we conducted airborne laser scanning to measure snow depth in the high elevation area including above the forest line twice in the same target area (in 2012 and 2015) and analyzed the relationships of snow depth above the forest line and some indicators of terrain. Our target area was the Chubetsu dam basin. It's located in central Hokkaido, a high elevation area in a mountainous region. Hokkaido is a northernmost island of Japan. Therefore it's a cold and snowy region. The target range for airborne laser scanning was 10km2. About 60% of the target range was above the forest line. First, we analyzed the relationship between elevation and snow depth. Below the forest line, the snow depth increased linearly with elevation increase. On the other hand, above the forest line, the snow depth varied greatly. Second, we analyzed the relationship between overground-openness and snow depth above the forest line. Overground-openness is an indicator quantifying how far a target point is above or below the surrounding surface. As a result, a simple relationship was clarified. Snow depth decreased linearly as overground-openness increases. This means that areas with heavy snow cover are

  14. Long-range laser scanning and 3D imaging for the Gneiss quarries survey

    NASA Astrophysics Data System (ADS)

    Schenker, Filippo Luca; Spataro, Alessio; Pozzoni, Maurizio; Ambrosi, Christian; Cannata, Massimiliano; Günther, Felix; Corboud, Federico

    2016-04-01

    In Canton Ticino (Southern Switzerland), the exploitation of natural stone, mostly gneisses, is an important activity of valley's economies. Nowadays, these economic activities are menaced by (i) the exploitation costs related to geological phenomena such as fractures, faults and heterogeneous rocks that hinder the processing of the stone product, (ii) continuously changing demand because of the evolving natural stone fashion and (iii) increasing administrative limits and rules acting to protect the environment. Therefore, the sustainable development of the sector for the next decades needs new and effective strategies to regulate and plan the quarries. A fundamental step in this process is the building of a 3D geological model of the quarries to constrain the volume of commercial natural stone and the volume of waste. In this context, we conducted Terrestrial Laser Scanning surveys of the quarries in the Maggia Valley to obtain a detailed 3D topography onto which the geological units were mapped. The topographic 3D model was obtained with a long-range laser scanning Riegl VZ4000 that can measure from up to 4 km of distance with a speed of 147,000 points per second. It operates with the new V-line technology, which defines the surface relief by sensing differentiated signals (echoes), even in the presence of obstacles such as vegetation. Depending on the esthetics of the gneisses, we defined seven types of natural stones that, together with faults and joints, were mapped onto the 3D models of the exploitation sites. According to the orientation of the geological limits and structures, we projected the different rock units and fractures into the excavation front. This way, we obtained a 3D geological model from which we can quantitatively estimate the volume of the seven different natural stones (with different commercial value) and waste (with low commercial value). To verify the 3D geological models and to quantify exploited rock and waste volumes the same

  15. Digital Terrain Models from Mobile Laser Scanning Data in Moravian Karst

    NASA Astrophysics Data System (ADS)

    Tyagur, N.; Hollaus, M.

    2016-06-01

    During the last ten years, mobile laser scanning (MLS) systems have become a very popular and efficient technology for capturing reality in 3D. A 3D laser scanner mounted on the top of a moving vehicle (e.g. car) allows the high precision capturing of the environment in a fast way. Mostly this technology is used in cities for capturing roads and buildings facades to create 3D city models. In our work, we used an MLS system in Moravian Karst, which is a protected nature reserve in the Eastern Part of the Czech Republic, with a steep rocky terrain covered by forests. For the 3D data collection, the Riegl VMX 450, mounted on a car, was used with integrated IMU/GNSS equipment, which provides low noise, rich and very dense 3D point clouds. The aim of this work is to create a digital terrain model (DTM) from several MLS data sets acquired in the neighbourhood of a road. The total length of two covered areas is 3.9 and 6.1 km respectively, with an average width of 100 m. For the DTM generation, a fully automatic, robust, hierarchic approach was applied. The derivation of the DTM is based on combinations of hierarchical interpolation and robust filtering for different resolution levels. For the generation of the final DTMs, different interpolation algorithms are applied to the classified terrain points. The used parameters were determined by explorative analysis. All MLS data sets were processed with one parameter set. As a result, a high precise DTM was derived with high spatial resolution of 0.25 x 0.25 m. The quality of the DTMs was checked by geodetic measurements and visual comparison with raw point clouds. The high quality of the derived DTM can be used for analysing terrain changes and morphological structures. Finally, the derived DTM was compared with the DTM of the Czech Republic (DMR 4G) with a resolution of 5 x 5 m, which was created from airborne laser scanning data. The vertical accuracy of the derived DTMs is around 0.10 m.

  16. Terrestrial Laser Scanning in Fluvial Geomorphology: Retrieving Morphological and Sedimentological Models of Gravel Bed Rivers

    NASA Astrophysics Data System (ADS)

    Brasington, J.; Vericat, D.; Rychkov, I.

    2009-04-01

    Developments in survey technology have enabled a revolution in the study of river morphology and fluvial processes. Terrestrial Laser Scanning technology offers the potential to acquire rapidly, reach-scale datasets which record topographic information at the resolution of bed grain-scale upwards. Based on time-of-flight or phase-based laser ranging, these instruments are capable of acquiring unprecedented volumes of survey-grade observations at operating frequencies of between 5-500 kHz and over ranges 25-1000 m. This hitherto unprecedented data-stream presents new opportunities for river science, but also creates significant challenges particularly associated with: data management; regularization of resolution; visualization; and data assimilation with parallel models and data-products. In this paper we present a new methodology designed to analyze large 3d point clouds generated by terrestrial laser scanning. Specifically, the approach generates multi-resolution gridded terrain products from scan data whilst retaining the sub-grid scale information as key statistical attributes. We apply the method in two field sites: (a) a 1 km reach of the River Feshie, Scotland which was scanned in 2007 and (b) a 500 m reach of the actively braided Rees River, New Zealand which was scanned before and after 3 competent events in January 2008. In the first case we evaluate the results from the method through a comparison with independently acquired, spatially dense, GPS surveys of the study reach. The results reveal significant differences in the topographic signatures recorded by the two methods and reveal the value of the enhanced spatial resolution for representing complex morphologies and highlight the potential to retrieve grain-scale sorting patterns from the statistical attributes of the TLS data. In the case of the New Zealand data set, the results demonstrate that TLS can be applied to recover centimetre-scale channel morphology, maps of particle size, sorting, packing

  17. Diameter distribution estimation with laser scanning based multisource single tree inventory

    NASA Astrophysics Data System (ADS)

    Kankare, Ville; Liang, Xinlian; Vastaranta, Mikko; Yu, Xiaowei; Holopainen, Markus; Hyyppä, Juha

    2015-10-01

    Tree detection and tree species recognition are bottlenecks of the airborne remote sensing-based single tree inventories. The effect of these factors in forest attribute estimation can be reduced if airborne measurements are aided with tree mapping information that is collected from the ground. The main objective here was to demonstrate the use of terrestrial laser scanning-derived (TLS) tree maps in aiding airborne laser scanning-based (ALS) single tree inventory (multisource single tree inventory, MS-STI) and its capability in predicting diameter distribution in various forest conditions. Automatic measurement of TLS point clouds provided the tree maps and the required reference information from the tree attributes. The study area was located in Evo, Finland, and the reference data was acquired from 27 different sample plots with varying forest conditions. The workflow of MS-STI included: (1) creation of automatic tree map from TLS point clouds, (2) automatic diameter at breast height (DBH) measurement from TLS point clouds, (3) individual tree detection (ITD) based on ALS, (4) matching the ITD segments to the field-measured reference, (5) ALS point cloud metric extraction from the single tree segments and (6) DBH estimation based on the derived metrics. MS-STI proved to be accurate and efficient method for DBH estimation and predicting diameter distribution. The overall accuracy (root mean squared error, RMSE) of the DBH was 36.9 mm. Results showed that the DBH accuracy decreased if the tree density (trees/ha) increased. The highest accuracies were found in old-growth forests (tree densities less than 500 stems/ha). MS-STI resulted in the best accuracies regarding Norway spruce (Picea abies (L.) H. Karst.)-dominated forests (RMSE of 29.9 mm). Diameter distributions were predicted with low error indices, thereby resulting in a good fit compared to the reference. Based on the results, diameter distribution estimation with MS-STI is highly dependent on the forest

  18. High Resolution Airborne Laser Scanning and Hyperspectral Imaging with a Small Uav Platform

    NASA Astrophysics Data System (ADS)

    Gallay, Michal; Eck, Christoph; Zgraggen, Carlo; Kaňuk, Ján; Dvorný, Eduard

    2016-06-01

    The capabilities of unmanned airborne systems (UAS) have become diverse with the recent development of lightweight remote sensing instruments. In this paper, we demonstrate our custom integration of the state-of-the-art technologies within an unmanned aerial platform capable of high-resolution and high-accuracy laser scanning, hyperspectral imaging, and photographic imaging. The technological solution comprises the latest development of a completely autonomous, unmanned helicopter by Aeroscout, the Scout B1-100 UAV helicopter. The helicopter is powered by a gasoline two-stroke engine and it allows for integrating 18 kg of a customized payload unit. The whole system is modular providing flexibility of payload options, which comprises the main advantage of the UAS. The UAS integrates two kinds of payloads which can be altered. Both payloads integrate a GPS/IMU with a dual GPS antenna configuration provided by OXTS for accurate navigation and position measurements during the data acquisition. The first payload comprises a VUX-1 laser scanner by RIEGL and a Sony A6000 E-Mount photo camera. The second payload for hyperspectral scanning integrates a push-broom imager AISA KESTREL 10 by SPECIM. The UAS was designed for research of various aspects of landscape dynamics (landslides, erosion, flooding, or phenology) in high spectral and spatial resolution.

  19. Observation of the early stage of insulin crystallization by confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Mühlig, P.; Klupsch, Th.; Schell, U.; Hilgenfeld, R.

    2001-11-01

    It is demonstrated that high resolution confocal laser scanning microscopy (CLSM) is a powerful tool for in situ observation and analysis of protein crystal growth. CLSM is used to study the early crystallization stage of Des-ThrB30 human insulin in aqueous solution, under conditions known to lead to monoclinic crystals. A modified batch crystallization method for CLSM purposes is applied which allows the growth behavior of crystallites to be studied in reflected light. A few hours after the start of the experiment, microcrystallites of characteristic shapes (mainly prismatic and pyramidal) are observed, the number of which strongly depends on the concentration of higher insulin aggregates in the initial solution. From direct observation as well as from model calculations we conclude that for solute concentrations up to about 3.5-times the saturation value, growth starts from few active insulin precipitate particles while 3D nucleation is neglegible for observation times up to 24 h. The anisotropic growth rates of monoclinic, prismatic crystallites are measured along the long edge of the cover face and perpendicular to the latter. A simultaneous crossover to signifcantly higher growth rates is found when the crystallite size reaches about 2 μm. The higher growth rates are connected with the appearence of striations. We argue that this growth rate crossover is caused by an increased 2D nucleation rate at the edges and corners, which finally results in bunching of steps simultaneously spreading over adjacent crystallite faces.

  20. Grammar-based Automatic 3D Model Reconstruction from Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Yu, Q.; Helmholz, P.; Belton, D.; West, G.

    2014-04-01

    The automatic reconstruction of 3D buildings has been an important research topic during the last years. In this paper, a novel method is proposed to automatically reconstruct the 3D building models from segmented data based on pre-defined formal grammar and rules. Such segmented data can be extracted e.g. from terrestrial or mobile laser scanning devices. Two steps are considered in detail. The first step is to transform the segmented data into 3D shapes, for instance using the DXF (Drawing Exchange Format) format which is a CAD data file format used for data interchange between AutoCAD and other program. Second, we develop a formal grammar to describe the building model structure and integrate the pre-defined grammars into the reconstruction process. Depending on the different segmented data, the selected grammar and rules are applied to drive the reconstruction process in an automatic manner. Compared with other existing approaches, our proposed method allows the model reconstruction directly from 3D shapes and takes the whole building into account.

  1. Plasmon resonance and the imaging of metal-impregnated neurons with the laser scanning confocal microscope

    PubMed Central

    Thompson, Karen J; Harley, Cynthia M; Barthel, Grant M; Sanders, Mark A; Mesce, Karen A

    2015-01-01

    The staining of neurons with silver began in the 1800s, but until now the great resolving power of the laser scanning confocal microscope has not been utilized to capture the in-focus and three-dimensional cytoarchitecture of metal-impregnated cells. Here, we demonstrate how spectral confocal microscopy, typically reserved for fluorescent imaging, can be used to visualize metal-labeled tissues. This imaging does not involve the reflectance of metal particles, but rather the excitation of silver (or gold) nanoparticles and their putative surface plasmon resonance. To induce such resonance, silver or gold particles were excited with visible-wavelength laser lines (561 or 640 nm), and the maximal emission signal was collected at a shorter wavelength (i.e., higher energy state). Because the surface plasmon resonances of noble metal nanoparticles offer a superior optical signal and do not photobleach, our novel protocol holds enormous promise of a rebirth and further development of silver- and gold-based cell labeling protocols. DOI: http://dx.doi.org/10.7554/eLife.09388.001 PMID:26670545

  2. Approach to quantify human dermal skin aging using multiphoton laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Puschmann, Stefan; Rahn, Christian-Dennis; Wenck, Horst; Gallinat, Stefan; Fischer, Frank

    2012-03-01

    Extracellular skin structures in human skin are impaired during intrinsic and extrinsic aging. Assessment of these dermal changes is conducted by subjective clinical evaluation and histological and molecular analysis. We aimed to develop a new parameter for the noninvasive quantitative determination of dermal skin alterations utilizing the high-resolution three-dimensional multiphoton laser scanning microscopy (MPLSM) technique. To quantify structural differences between chronically sun-exposed and sun-protected human skin, the respective collagen-specific second harmonic generation and the elastin-specific autofluorescence signals were recorded in young and elderly volunteers using the MPLSM technique. After image processing, the elastin-to-collagen ratio (ELCOR) was calculated. Results show that the ELCOR parameter of volar forearm skin significantly increases with age. For elderly volunteers, the ELCOR value calculated for the chronically sun-exposed temple area is significantly augmented compared to the sun-protected upper arm area. Based on the MPLSM technology, we introduce the ELCOR parameter as a new means to quantify accurately age-associated alterations in the extracellular matrix.

  3. 3-D reconstruction of neurons from multichannel confocal laser scanning image series.

    PubMed

    Wouterlood, Floris G

    2014-01-01

    A confocal laser scanning microscope (CLSM) collects information from a thin, focal plane and ignores out-of-focus information. Scanning of a specimen, with stepwise axial (Z-) movement of the stage in between each scan, produces Z-series of confocal images of a tissue volume, which then can be used to 3-D reconstruct structures of interest. The operator first configures separate channels (e.g., laser, filters, and detector settings) for each applied fluorochrome and then acquires Z-series of confocal images: one series per channel. Channel signal separation is extremely important. Measures to avoid bleaching are vital. Post-acquisition deconvolution of the image series is often performed to increase resolution before 3-D reconstruction takes place. In the 3-D reconstruction programs described in this unit, reconstructions can be inspected in real time from any viewing angle. By altering viewing angles and by switching channels off and on, the spatial relationships of 3-D-reconstructed structures with respect to structures visualized in other channels can be studied. Since each brand of CLSM, computer program, and 3-D reconstruction package has its own proprietary set of procedures, a general approach is provided in this protocol wherever possible. PMID:24723320

  4. Detection of lying tree stems from airborne laser scanning data using a line template matching algorithm

    NASA Astrophysics Data System (ADS)

    Lindberg, E.; Hollaus, M.; Mücke, W.; Fransson, J. E. S.; Pfeifer, N.

    2013-10-01

    Dead wood is an important habitat characteristic in forests. However, dead wood lying on the ground below a canopy is difficult to detect from remotely sensed data. Data from airborne laser scanning include measurement of surfaces below the canopy, thus offering the potential to model objects on the ground. This paper describes a new line template matching algorithm for detecting lines along the ground. The line template matching is done directly to the laser point cloud and results in a raster showing the support of the line in each raster cell. Line elements are vectorized based on the raster to represent lying tree stems. The results have been validated versus field-measured lying tree stems. The number of detected lines was 845, of which 268 could be automatically linked to the 651 field-measured stems. The line template matching produced a raster which visually showed linear elements in areas where lying tree stems where present, but the result is difficult to compare with the field measurements due to positioning errors. The study area contained big piles of storm-felled trees in some places, which made it an unusually complex test site. Longer line structures such as ditches and roads also resulted in detected lines and further analysis is needed to avoid this, for example by specifically detecting longer lines and removing them.

  5. Automatic Extraction of Road Surface and Curbstone Edges from Mobile Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Miraliakbari, A.; Hahn, M.; Sok, S.

    2015-05-01

    We present a procedure for automatic extraction of the road surface from geo-referenced mobile laser scanning data. The basic assumption of the procedure is that the road surface is smooth and limited by curbstones. Two variants of jump detection are investigated for detecting curbstone edges, one based on height differences the other one based on histograms of the height data. Region growing algorithms are proposed which use the irregular laser point cloud. Two- and four-neighbourhood growing strategies utilize the two height criteria for examining the neighborhood. Both height criteria rely on an assumption about the minimum height of a low curbstone. Road boundaries with lower or no jumps will not stop the region growing process. In contrast to this objects on the road can terminate the process. Therefore further processing such as bridging gaps between detected road boundary points and the removal of wrongly detected curbstone edges is necessary. Road boundaries are finally approximated by splines. Experiments are carried out with a ca. 2 km network of smalls streets located in the neighbourhood of University of Applied Sciences in Stuttgart. For accuracy assessment of the extracted road surfaces, ground truth measurements are digitized manually from the laser scanner data. For completeness and correctness of the region growing result values between 92% and 95% are achieved.

  6. (Semi) automatic extraction from airborne laser scan data of roads and paths in forested areas

    NASA Astrophysics Data System (ADS)

    Vletter, Willem F.

    2014-08-01

    The possibilities of airborne laser scanning as a tool for visualisation of micro topology have been known for some decades. Indeed, in the archaeological field a lot of new features have been detected or reconfirmed. However, the task to map manually the enormous amount of features is time consuming and costly. Therefore, there is a need for automation. In this paper four workflows of visualisation and (semi) automatic extraction of (historical) roads and paths are compared. It proved that the concept of openness is preferred over the break line concept for visualisation. Regarding the extraction the software plug in Feature Analyst showed the best results. Openness and Feature Analyst stand also out when costs and processing time were considered. Therefore, we suggest the workflow which combines openness, for visualisation, and Feature Analyst for extraction. The results of this study contribute to the development of automatic extraction techniques in general. In this regard software packages like eCognition look promising to improve extraction methods.

  7. Combined use of terrestrial laser scanning and IR thermography applied to a historical building.

    PubMed

    Costanzo, Antonio; Minasi, Mario; Casula, Giuseppe; Musacchio, Massimo; Buongiorno, Maria Fabrizia

    2015-01-01

    The conservation of architectural heritage usually requires a multidisciplinary approach involving a variety of specialist expertise and techniques. Nevertheless, destructive techniques should be avoided, wherever possible, in order to preserve the integrity of the historical buildings, therefore the development of non-destructive and non-contact techniques is extremely important. In this framework, a methodology for combining the terrestrial laser scanning and the infrared thermal images is proposed, in order to obtain a reconnaissance of the conservation state of a historical building. The proposed case study is represented by St. Augustine Monumental Compound, located in the historical centre of the town of Cosenza (Calabria, South Italy). Adopting the proposed methodology, the paper illustrates the main results obtained for the building test overlaying and comparing the collected data with both techniques, in order to outline the capabilities both to detect the anomalies and to improve the knowledge on health state of the masonry building. The 3D model, also, allows to provide a reference model, laying the groundwork for implementation of a monitoring multisensor system based on the use of non-destructive techniques. PMID:25609042

  8. Landslides Identification Using Airborne Laser Scanning Data Derived Topographic Terrain Attributes and Support Vector Machine Classification

    NASA Astrophysics Data System (ADS)

    Pawłuszek, Kamila; Borkowski, Andrzej

    2016-06-01

    Since the availability of high-resolution Airborne Laser Scanning (ALS) data, substantial progress in geomorphological research, especially in landslide analysis, has been carried out. First and second order derivatives of Digital Terrain Model (DTM) have become a popular and powerful tool in landslide inventory mapping. Nevertheless, an automatic landslide mapping based on sophisticated classifiers including Support Vector Machine (SVM), Artificial Neural Network or Random Forests is often computationally time consuming. The objective of this research is to deeply explore topographic information provided by ALS data and overcome computational time limitation. For this reason, an extended set of topographic features and the Principal Component Analysis (PCA) were used to reduce redundant information. The proposed novel approach was tested on a susceptible area affected by more than 50 landslides located on Rożnów Lake in Carpathian Mountains, Poland. The initial seven PCA components with 90% of the total variability in the original topographic attributes were used for SVM classification. Comparing results with landslide inventory map, the average user's accuracy (UA), producer's accuracy (PA), and overall accuracy (OA) were calculated for two models according to the classification results. Thereby, for the PCA-feature-reduced model UA, PA, and OA were found to be 72%, 76%, and 72%, respectively. Similarly, UA, PA, and OA in the non-reduced original topographic model, was 74%, 77% and 74%, respectively. Using the initial seven PCA components instead of the twenty original topographic attributes does not significantly change identification accuracy but reduce computational time.

  9. Detection and Classification of Changes in Buildings from Airborne Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Xu, S.; Vosselman, G.; Oude Elberink, S.

    2013-10-01

    Building change detection serves to investigate illegal buildings. Illegal built or removed structures, especially those concealed among gable roofs such as dormers, are difficult to track among potentially millions of buildings. Nevertheless, they can be efficiently located in changed areas. An approach is proposed to automatically detect and classify changes in buildings from two epochs of Airborne Laser Scanning Data. Both datasets are classified into water, ground, building, vegetation and undefined objects in advance. After generalization of a 3D surface separation map, we verify changes by making rules on the separation map. Changes belonging to buildings are then classified into roof, wall, dormers, vehicles, construction above roof and undefined objects. As the ALS data has accuracy in strip difference of lower than 5 cm within the same epoch and from different epochs, changes that are larger than 10 cm were detected. Building changes, which areas are larger than 4 m2, are identified as change. By inspection, nearly all changes are detected and approximately 80% changes are correctly classified.

  10. Characterization of landslide ground surface kinematics from terrestrial laser scanning and strain field computation

    NASA Astrophysics Data System (ADS)

    Teza, Giordano; Pesci, Arianna; Genevois, Rinaldo; Galgaro, Antonio

    2008-05-01

    Assessment and mitigation of the risk induced by landslide activation need an appropriate phenomenon investigation, to obtain useful information about the failure processes. The first step is the complete kinematics characterization of the landslide ground surface, by evaluating the involved displacement and deformation patterns. A dense displacement field can be obtained from comparison of a series of multi-temporal observations performed by means of terrestrial laser scanning. Subsequently, the strain field can be computed from displacement vectors. In this paper, a modified least square technique is employed to compute the strain on the nodes of a regular grid (2D approach) or on the points of a digital terrain model (3D approach). Such a computation takes into account the displacements, their spatial distribution, as well as the measurement and modelling errors. A scale factor is introduced in order to emphasize the contributions of the experimental points on the basis of their distance from each computation point, and to recognize possible scale-depending behaviours. This method has been implemented in Matlab and applied on two landslides located in the northeastern Italian Alps (Lamosano and Perarolo di Cadore). The experiments show that different kinematics can be recognized, and the presence and influence of eventual discontinuities can be revealed.

  11. Monitoring of Fluvial Transport in the Mountain River Bed Using Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Jozkow, G.; Borkowski, A.; Kasprzak, M.

    2016-06-01

    The fluvial transport is the surface process that has a strong impact on the topography changes, especially in mountain areas. Traditional hydrological measurements usually give a good understanding of the river flow, however, the information of the bedload movement in the rivers is still insufficient. In particular, there is limited knowledge about the movement of the largest clasts, i.e. boulders. This investigation addresses mentioned issues by employing Terrestrial Laser Scanning (TLS) to monitor annual changes of the mountain river bed. The vertical changes were estimated based on the Digital Elevation Model (DEM) of difference (DoD) while transported boulders were identified based on the distances between point clouds and RGB-coloured points. Combined RGB point clouds allowed also to measure 3D displacements of boulders. The results showed that the highest dynamic of the fluvial process occurred between years 2012-2013. Obtained DoD clearly indicated alternating zones of erosion and deposition of the sediment finer fractions in the local sedimentary traps. The horizontal displacement of the rock material in the river bed showed high complexity resulting in the displacement of large boulders (major axis about 0.8 m) for the distance up to 2.3 m.

  12. Fast and Robust STEM Reconstruction in Complex Environments Using Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Wang, D.; Hollaus, M.; Puttonen, E.; Pfeifer, N.

    2016-06-01

    Terrestrial Laser Scanning (TLS) is an effective tool in forest research and management. However, accurate estimation of tree parameters still remains challenging in complex forests. In this paper, we present a novel algorithm for stem modeling in complex environments. This method does not require accurate delineation of stem points from the original point cloud. The stem reconstruction features a self-adaptive cylinder growing scheme. This algorithm is tested for a landslide region in the federal state of Vorarlberg, Austria. The algorithm results are compared with field reference data, which show that our algorithm is able to accurately retrieve the diameter at breast height (DBH) with a root mean square error (RMSE) of ~1.9 cm. This algorithm is further facilitated by applying an advanced sampling technique. Different sampling rates are applied and tested. It is found that a sampling rate of 7.5% is already able to retain the stem fitting quality and simultaneously reduce the computation time significantly by ~88%.

  13. Assessing and modeling moose (Alces alces) habitats with airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Melin, M.; Packalén, P.; Matala, J.; Mehtätalo, L.; Pusenius, J.

    2013-08-01

    In the analysis of forest resources, the use of ALS (airborne laser scanning) enables detailed three dimensional (3D) descriptions of forests and their vegetation. Simultaneously, ecologists have recognized that 3D information on vegetation is highly important in analyzing the habitat suitability of a given site. Recently, animals’ habitat preferences have been analyzed, for example, with GPS-collared animals. This has resulted in detailed knowledge about the animals’ movements both spatially and temporally. This study combines 3D information on vegetation obtained from ALS data with information about animal locations from GPS data. The aim was to map and analyze the habitat preferences of moose. The study area was located on the west coast of Finland. The data consisted of 18 GPS-collared moose (monitored from 2009 to 2010) and ALS data collected in 2010. We investigated how habitat structure changes as a function of distance to observed moose locations and how observed moose locations differ from randomly selected locations in terms of 3D structure. We also created a model-based habitat suitability map and tested it against moose occurrences. The results suggested that there are clear differences between the areas occupied and not occupied by moose and that these differences can be detected from ALS data. More importantly, ALS proved its potential in linking 3D descriptions of vegetation directly to observed moose locations without any proxy variables. These observations strongly support future studies.

  14. a Feasibility Study on Use of Generic Mobile Laser Scanning System for Detecting Asphalt Pavement Cracks

    NASA Astrophysics Data System (ADS)

    Chen, Xinqu; Li, Jonathan

    2016-06-01

    This study aims to automatically detect pavement cracks on urban roads by employing the 3D point clouds acquired by a mobile laser scanning (MLS) system. Our method consists of four steps: ground point filtering, high-pass convolution, matched filtering, and noise removal. First, a voxel-based upward growing method is applied to construct Digital Terrain Model (DTM) of the road surface. Then, a high-pass filter convolutes the DTM to detect local elevation changes that may embed cracking information. Next, a two-step matched filter is applied to extract crack features. Lastly, a noise removal process is conducted to refine the results. Instead of using MLS intensity, this study takes advantages of the MLS elevation information to perform automated crack detection from large-volume, mixed-density, unstructured MLS point clouds. Four types of cracks including longitudinal, transvers, random, and alligator cracks are detected. Our results demonstrated that the proposed method works well with the RIEGL VMX-450 point clouds and can detect cracks in moderate-to-severe severity (13 - 25 mm) within a 200 m by 30 m urban road segment located in Kingston, Ontario, at one time. Due to the resolution capability, small cracks with slight severity remain unclear in the MLS point cloud.

  15. Adaptive circle-ellipse fitting method for estimating tree diameter based on single terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Bu, Guochao; Wang, Pei

    2016-04-01

    Terrestrial laser scanning (TLS) has been used to extract accurate forest biophysical parameters for inventory purposes. The diameter at breast height (DBH) is a key parameter for individual trees because it has the potential for modeling the height, volume, biomass, and carbon sequestration potential of the tree based on empirical allometric scaling equations. In order to extract the DBH from the single-scan data of TLS automatically and accurately within a certain range, we proposed an adaptive circle-ellipse fitting method based on the point cloud transect. This proposed method can correct the error caused by the simple circle fitting method when a tree is slanted. A slanted tree was detected by the circle-ellipse fitting analysis, then the corresponding slant angle was found based on the ellipse fitting result. With this information, the DBH of the trees could be recalculated based on reslicing the point cloud data at breast height. Artificial stem data simulated by a cylindrical model of leaning trees and the scanning data acquired with the RIEGL VZ-400 were used to test the proposed adaptive fitting method. The results shown that the proposed method can detect the trees and accurately estimate the DBH for leaning trees.

  16. Integrating optical satellite data and airborne laser scanning in habitat classification for wildlife management

    NASA Astrophysics Data System (ADS)

    Nijland, W.; Coops, N. C.; Nielsen, S. E.; Stenhouse, G.

    2015-06-01

    Wildlife habitat selection is determined by a wide range of factors including food availability, shelter, security and landscape heterogeneity all of which are closely related to the more readily mapped landcover types and disturbance regimes. Regional wildlife habitat studies often used moderate resolution multispectral satellite imagery for wall to wall mapping, because it offers a favourable mix of availability, cost and resolution. However, certain habitat characteristics such as canopy structure and topographic factors are not well discriminated with these passive, optical datasets. Airborne laser scanning (ALS) provides highly accurate three dimensional data on canopy structure and the underlying terrain, thereby offers significant enhancements to wildlife habitat mapping. In this paper, we introduce an approach to integrate ALS data and multispectral images to develop a new heuristic wildlife habitat classifier for western Alberta. Our method combines ALS direct measures of canopy height, and cover with optical estimates of species (conifer vs. deciduous) composition into a decision tree classifier for habitat - or landcover types. We believe this new approach is highly versatile and transferable, because class rules can be easily adapted for other species or functional groups. We discuss the implications of increased ALS availability for habitat mapping and wildlife management and provide recommendations for integrating multispectral and ALS data into wildlife management.

  17. Supraresolution imaging in brain slices using stimulated-emission depletion 2-photon laser scanning microscopy

    PubMed Central

    Ding, Jun; Takasaki, Kevin T.; Sabatini, Bernardo L.

    2009-01-01

    SUMMARY Two-photon laser scanning microscopy (2PLSM) has allowed unprecedented fluorescent imaging of neuronal structure and function within neural tissue. However, the resolution of this approach is poor compared to that of conventional confocal microscopy. Here we demonstrate supraresolution 2PLSM within brain slices. Imaging beyond the diffraction limit is accomplished by using near-infrared (NIR) lasers for both pulsed 2-photon excitation and continuous wave stimulation emission depletion (STED). Furthermore, we demonstrate that Alexa Fluor-594, a bright fluorophore commonly used for both live cell and fixed tissue fluorescence imaging, is suitable for STED 2PLSM. STED 2PLSM supraresolution microscopy achieves approximately 3 fold improvement in resolution in the radial direction over conventional 2PLSM, revealing greater detail in the structure of dendritic spines located ~100 microns below the surface of brain slices. Further improvements in resolution are theoretically achievable, suggesting that STED 2PLSM will permit nanoscale imaging of neuronal structures located in relatively intact brain tissue. PMID:19709626

  18. Comparison between optical-resolution photoacoustic microscopy and confocal laser scanning microscopy for turbid sample imaging

    NASA Astrophysics Data System (ADS)

    U-Thainual, Paweena; Kim, Do-Hyun

    2015-12-01

    Optical-resolution photoacoustic microscopy (ORPAM) in theory provides lateral resolution equivalent to the optical diffraction limit. Scattering media, such as biological turbid media, attenuates the optical signal and also alters the diffraction-limited spot size of the focused beam. The ORPAM signal is generated only from a small voxel in scattering media with dimensions equivalent to the laser spot size after passing through scattering layers and is detected by an acoustic transducer, which is not affected by optical scattering. Thus, both ORPAM and confocal laser scanning microscopy (CLSM) reject scattered light. A multimodal optical microscopy platform that includes ORPAM and CLSM was constructed, and the lateral resolution of both modes was measured using patterned thin metal film with and without a scattering barrier. The effect of scattering media on the lateral resolution was studied using different scattering coefficients and was compared to computational results based on Monte Carlo simulations. It was found that degradation of lateral resolution due to optical scattering was not significant for either ORPAM or CLSM. The depth discrimination capability of ORPAM and CLSM was measured using microfiber embedded in a light scattering phantom material. ORPAM images demonstrated higher contrast compared to CLSM images partly due to reduced acoustic signal scattering.

  19. Comparison between optical-resolution photoacoustic microscopy and confocal laser scanning microscopy for turbid sample imaging.

    PubMed

    U-Thainual, Paweena; Kim, Do-Hyun

    2015-12-01

    Optical-resolution photoacoustic microscopy (ORPAM) in theory provides lateral resolution equivalent to the optical diffraction limit. Scattering media, such as biological turbid media, attenuates the optical signal and also alters the diffraction-limited spot size of the focused beam. The ORPAM signal is generated only from a small voxel in scattering media with dimensions equivalent to the laser spot size after passing through scattering layers and is detected by an acoustic transducer, which is not affected by optical scattering. Thus, both ORPAM and confocal laser scanning microscopy (CLSM) reject scattered light. A multimodal optical microscopy platform that includes ORPAM and CLSM was constructed, and the lateral resolution of both modes was measured using patterned thin metal film with and without a scattering barrier. The effect of scattering media on the lateral resolution was studied using different scattering coefficients and was compared to computational results based on Monte Carlo simulations. It was found that degradation of lateral resolution due to optical scattering was not significant for either ORPAM or CLSM. The depth discrimination capability of ORPAM and CLSM was measured using microfiber embedded in a light scattering phantom material. ORPAM images demonstrated higher contrast compared to CLSM images partly due to reduced acoustic signal scattering. PMID:26256640

  20. Error Analysis of Terrestrial Laser Scanning Data by Means of Spherical Statistics and 3D Graphs

    PubMed Central

    Cuartero, Aurora; Armesto, Julia; Rodríguez, Pablo G.; Arias, Pedro

    2010-01-01

    This paper presents a complete analysis of the positional errors of terrestrial laser scanning (TLS) data based on spherical statistics and 3D graphs. Spherical statistics are preferred because of the 3D vectorial nature of the spatial error. Error vectors have three metric elements (one module and two angles) that were analyzed by spherical statistics. A study case has been presented and discussed in detail. Errors were calculating using 53 check points (CP) and CP coordinates were measured by a digitizer with submillimetre accuracy. The positional accuracy was analyzed by both the conventional method (modular errors analysis) and the proposed method (angular errors analysis) by 3D graphics and numerical spherical statistics. Two packages in R programming language were performed to obtain graphics automatically. The results indicated that the proposed method is advantageous as it offers a more complete analysis of the positional accuracy, such as angular error component, uniformity of the vector distribution, error isotropy, and error, in addition the modular error component by linear statistics. PMID:22163461

  1. Quantitative characterization of the surface topography of rolled sheets by laser scanning microscopy and fourier transformation

    NASA Astrophysics Data System (ADS)

    Gjønnes, Liv

    1996-08-01

    The surface of twin-roll cast aluminum sheets undergoes dramatic changes during cold rolling. This is mainly due to variables in the roll gap, topography of the rolls, lubrication, material properties, and in particular the initial structure and topography of the cast sheet. Therefore, it is important to have means to quantitatively describe the changes in the surface structure of each pass and from pass to pass in order to optimize the desired final surface structure. To achieve this, the laser scanning microscope (LSM) with its confocal technique has been employed to image the three-dimensional (3-D) topography and to digitize the image for further computer analysis. The digitization of the image is primarily motivated by the need to introduce a Fourier transformation of the surface topography. The method is effective in describing qualitative periodic trends in the surface features. Information is gained on the shape and periodicities as well as roughness directionality. For instance, grooves and cross hatches and their remnants can be followed from one pass to the other. Important characteristics of the surface topography such as rolling ridges and shingles can also easily be characterized.

  2. The Laser Scan Data as a Key Element in the Hydraulic Flood Modelling in Urban Areas

    NASA Astrophysics Data System (ADS)

    Sole, A.; Giosa, L.; Albano, R.; Cantisani, A.

    2013-05-01

    This paper is intended to highlight the need to use data at high spatial resolution, such as those obtained through the use of Airborne Laser Scanning (ALS) techniques, to support hydraulic models for the assessment of flood hazards in urban territory. In fact, the significant structural features (houses, walls, roads, etc.) in the city are important in relation to both the volume of the floodplain that can be occupied by the flow and the direction that the flow takes across the floodplain. ALS data can range up to several terabytes in size and is a function of the geographic scale of the mission. Also, this data is typically irregular with uneven point density. Therefore, a quick method is described to ride out the difficulties to handle the large datasets with uneven point densities and to improve the extracting of feature information for further use in Geographic Information System (GIS) analysis. Finally, a comparison is made between the maximum inundated area obtained from ALS data and that one calculated using a traditional topographic map. The results show that the high-resolution data obtained from airborne remote sensing can increase the opportunities for representation of small-scale structural elements in complex systems using two-dimensional models of flood inundation.

  3. Laser scanning stereomicroscopy for fast volumetric imaging with two-photon excitation and scanned Bessel beams

    NASA Astrophysics Data System (ADS)

    Yang, Yanlong; Zhou, Xing; Li, Runze; Van Horn, Mark; Peng, Tong; Lei, Ming; Wu, Di; Chen, Xun; Yao, Baoli; Ye, Tong

    2015-03-01

    Bessel beams have been used in many applications due to their unique optical properties of maintaining their intensity profiles unchanged during propagation. In imaging applications, Bessel beams have been successfully used to provide extended focuses for volumetric imaging and uniformed illumination plane in light-sheet microscopy. Coupled with two-photon excitation, Bessel beams have been successfully used in realizing fluorescence projected volumetric imaging. We demonstrated previously a stereoscopic solution-two-photon fluorescence stereomicroscopy (TPFSM)-for recovering the depth information in volumetric imaging with Bessel beams. In TPFSM, tilted Bessel beams were used to generate stereoscopic images on a laser scanning two-photon fluorescence microscope; upon post image processing we could successfully provide 3D perception of acquired volume images by wearing anaglyph 3D glasses. However, tilted Bessel beams were generated by shifting either an axicon or an objective laterally; the slow imaging speed and severe aberrations made it hard to use in real-time volume imaging. In this article, we report recent improvements of TPFSM with newly designed scanner and imaging software, which allows 3D stereoscopic imaging without moving any of the optical components on the setup. This improvement has dramatically improved focusing qualities and imaging speed so that the TPFSM can be performed potentially in real-time to provide 3D visualization in scattering media without post image processing.

  4. Possibilities of a Personal Laser Scanning System for Forest Mapping and Ecosystem Services

    PubMed Central

    Liang, Xinlian; Kukko, Antero; Kaartinen, Harri; Hyyppä, Juha; Yu, Xiaowei; Jaakkola, Anttoni; Wang, Yunsheng

    2014-01-01

    A professional-quality, personal laser scanning (PLS) system for collecting tree attributes was demonstrated in this paper. The applied system, which is wearable by human operators, consists of a multi-constellation navigation system and an ultra-high-speed phase-shift laser scanner mounted on a rigid baseplate and consisting of a single sensor block. A multipass-corridor-mapping method was developed to process PLS data and a 2,000 m2 forest plot was utilized in the test. The tree stem detection accuracy was 82.6%; the root mean square error (RMSE) of the estimates of tree diameter at breast height (DBH) was 5.06 cm; the RMSE of the estimates of tree location was 0.38 m. The relative RMSE of the DBH estimates was 14.63%. The results showed, for the first time, the potential of the PLS system in mapping large forest plots. Further research on mapping accuracy in various forest conditions, data correction methods and multi-sensoral positioning techniques is needed. The utilization of this system in different applications, such as harvester operations, should also be explored. In addition to collecting tree-level and plot-level data for forest inventory, other possible applications of PLS for forest ecosystem services include mapping of canopy gaps, measuring leaf area index of large areas, documenting and visualizing forest routes feasible for recreation, hiking and berry and mushroom picking. PMID:24434879

  5. In Vivo Laser Scanning Confocal Microscopy of Human Meibomian Glands in Aging and Ocular Surface Diseases

    PubMed Central

    Fasanella, Vincenzo; Mastropasqua, Rodolfo; Brescia, Lorenza; Di Staso, Federico; Ciancaglini, Marco; Mastropasqua, Leonardo

    2016-01-01

    Meibomian glands (MGs) play a crucial role in the ocular surface homeostasis by providing lipids to the superficial tear film. Their dysfunction destabilizes the tear film leading to a progressive loss of the ocular surface equilibrium and increasing the risk for dry eye. In fact, nowadays, the meibomian gland dysfunction is one of the leading causes of dry eye. Over the past decades, MGs have been mainly studied by using meibography, which, however, cannot image the glandular structure at a cellular level. The diffusion of the in vivo laser scanning confocal microscopy (LSCM) provided a new approach for the structural assessment of MGs permitting a major step in the noninvasive evaluation of these structures. LSCM is capable of showing MGs modifications during aging and in the most diffuse ocular surface diseases such as dry eye, allergy, and autoimmune conditions and in the drug-induced ocular surface disease. On the other hand, LSCM may help clinicians in monitoring the tissue response to therapy. In this review, we summarized the current knowledge about the role of in vivo LSCM in the assessment of MGs during aging and in the most diffuse ocular surface diseases. PMID:27047965

  6. In Vivo Laser Scanning Confocal Microscopy of Human Meibomian Glands in Aging and Ocular Surface Diseases.

    PubMed

    Fasanella, Vincenzo; Agnifili, Luca; Mastropasqua, Rodolfo; Brescia, Lorenza; Di Staso, Federico; Ciancaglini, Marco; Mastropasqua, Leonardo

    2016-01-01

    Meibomian glands (MGs) play a crucial role in the ocular surface homeostasis by providing lipids to the superficial tear film. Their dysfunction destabilizes the tear film leading to a progressive loss of the ocular surface equilibrium and increasing the risk for dry eye. In fact, nowadays, the meibomian gland dysfunction is one of the leading causes of dry eye. Over the past decades, MGs have been mainly studied by using meibography, which, however, cannot image the glandular structure at a cellular level. The diffusion of the in vivo laser scanning confocal microscopy (LSCM) provided a new approach for the structural assessment of MGs permitting a major step in the noninvasive evaluation of these structures. LSCM is capable of showing MGs modifications during aging and in the most diffuse ocular surface diseases such as dry eye, allergy, and autoimmune conditions and in the drug-induced ocular surface disease. On the other hand, LSCM may help clinicians in monitoring the tissue response to therapy. In this review, we summarized the current knowledge about the role of in vivo LSCM in the assessment of MGs during aging and in the most diffuse ocular surface diseases. PMID:27047965

  7. Assessment of Relative Accuracy of AHN-2 Laser Scanning Data Using Planar Features

    PubMed Central

    van der Sande, Corné; Soudarissanane, Sylvie; Khoshelham, Kourosh

    2010-01-01

    AHN-2 is the second part of the Actueel Hoogtebestand Nederland project, which concerns the acquisition of high-resolution altimetry data over the entire Netherlands using airborne laser scanning. The accuracy assessment of laser altimetry data usually relies on comparing corresponding tie elements, often points or lines, in the overlapping strips. This paper proposes a new approach to strip adjustment and accuracy assessment of AHN-2 data by using planar features. In the proposed approach a transformation is estimated between two overlapping strips by minimizing the distances between points in one strip and their corresponding planes in the other. The planes and the corresponding points are extracted in an automated segmentation process. The point-to-plane distances are used as observables in an estimation model, whereby the parameters of a transformation between the two strips and their associated quality measures are estimated. We demonstrate the performance of the method for the accuracy assessment of the AHN-2 dataset over Zeeland province of The Netherlands. The results show vertical offsets of up to 4 cm between the overlapping strips, and horizontal offsets ranging from 2 cm to 34 cm. PMID:22163650

  8. Terrestrial laser scanning observations of geomorphic changes and varying lava lake levels at Erebus volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Jones, Laura K.; Kyle, Philip R.; Oppenheimer, Clive; Frechette, Jedediah D.; Okal, Marianne H.

    2015-03-01

    A Terrestrial Laser Scanning (TLS) instrument was used to image the topography of the Main Crater at Erebus volcano each December in 2008, 2009, and 2010. Our high-spatial resolution TLS scans provide unique insights into annual and decadal scale geomorphic evolution of the summit area when integrated with comparable data collected by an airborne instrument in 2001. We observe both a pattern of subsidence within the Inner Crater of the volcano and an ~ 3 m per-year drop in the lava lake level over the same time period that are suggestive of decreasing overpressure in an underlying magma reservoir. We also scanned the active phonolite lava lake hosted within the Inner Crater, and recorded rapid cyclic fluctuations in the level of the lake. These were sporadically interrupted by minor explosions by bursting gas bubbles at the lake surface. The TLS data permit calculation of lake level rise and fall speeds and associated rates of volumetric change within the lake. These new observations, when considered with prior determinations of rates of lake surface motion and gas output, are indicative of unsteady magma flow in the conduit and its associated variability in gas volume fraction.

  9. Topographical surveys: Classical method versus 3D laser scanning. Case study - An application in civil engineering

    NASA Astrophysics Data System (ADS)

    Grigoraş, I.-R.; Covăsnianu, A.; Pleşu, G.; Benedict, B.

    2009-04-01

    The paper describes an experiment which took place in Iasi town, Romania, consisted in two different topographical survey techniques applied for one and the same objective placed in a block within the city (western part) - a thermal power station. The purpose was to compare those methods and to determine which one is proper to be used in this domain in terms of fastness, optimization and speed of data processing. First technique applied for our survey was the classical one, with a total station. Using the CAD technique, we obtained a final product (a dwg file) and a list of coordinates (a text file). The second method, which we focused our attention more, was the measurement with a very precise 3D laser scanstation, also very suitable in archeology. The data obtained were processed with special software. Result was a 3D model of the thermal power plant composed of measurable cloud point data. Finally, analyzing the advantages and disadvantages of each method, we came to the conclusion that the 3D laser scanning which we used matches well the application, in this case civil engineering, but the future of accepting and implementing this technique is in the hands of Romanian authorities.

  10. Resolution enhancement of digital laser scanning fluorescence microscopy with a dual-lens optical pickup head

    NASA Astrophysics Data System (ADS)

    Tsai, Rung-Ywan; Chen, Jung-Po; Lee, Yuan-Chin; Chiang, Hung-Chih; Huang, Tai-Ting; Huang, Chun-Chieh; Cheng, Chih-Ming; Cheng, Chung-Ta; Lo, Feng-Hsiang; Tiao, Golden

    2016-07-01

    The resolution of the cell fluorescence image captured by a digital laser scanning microscopy with a modified dual-lens BD-ROM optical pickup head is enhanced by image registration and double sample frequency. A dual objective lens of red (655 nm) and blue (405 or 488 nm) laser sources with numerical apertures of 0.6 and 0.85 is used for sample focusing and position tracking and cell fluorescence image capturing, respectively. The image registration and capturing frequency are based on the address-coded patterns of a sample slide. The address-coded patterns are designed as a string of binary code, which comprises a plurality of base-straight lands and grooves and data-straight grooves. The widths of the base-straight lands, base-straight grooves, and data-straight grooves are 0.38, 0.38, and 0.76 μm, respectively. The numbers of sample signals in the x-direction are measured at every intersection point by intersecting the base intensity of the push-pull signal of the address-coded patterns, which has a minimum spacing of 0.38 μm. After taking a double sample frequency, the resolution of the measured cell fluorescence image is enhanced from 0.38 μm to the diffraction limit of the objective lens.

  11. Analysis of shallow landslides by morphometry parameters derived from terrestrial laser scanning point clouds

    NASA Astrophysics Data System (ADS)

    Mayr, A.; Rutzinger, M.; Bremer, M.; Wiegand, C.; Kringer, K.; Geitner, C.

    2012-04-01

    Erosion by shallow landslides is a widespread and growing phenomenon in mountainous areas. The major consequences are loss of soil and regolith as well as damages on infrastructure and provision of unconsolidated material for secondary processes such as mudflows. In this study we present a concept for extracting morphometry parameters from terrestrial laser scanning (TLS) point clouds in order to investigate the relation between slope surface structure and regolith depth. TLS is used to collect high-resolution point cloud data of an affected slope in the Schmirn Valley (Tyrol, Austria). Regolith depth is considered to be one of the important factors for the development of shallow landslides. However, direct field measurements are labour- and time-consuming. In this study we developed an approach, to investigate the relation between regolith depth and surface morphometry parameters. The reference regolith depth information is derived from lightweight dynamic cone penetrometer tests (DCPT) within the test site. The suggested approach integrates spatial analysis of Geographic Information Systems and point cloud processing algorithms. It will help to enhance the prediction of shallow landslide occurrence by (i) deriving high resolution 3D morphometric parameters and (ii) determining regolith depth with a reasonable effort due to automation. In future we want to be able to contribute with this concept to the detailed modelling of shallow landslide susceptibility on alpine slopes.

  12. Co-Registration of DSMs Generated by Uav and Terrestrial Laser Scanning Systems

    NASA Astrophysics Data System (ADS)

    Ancil Persad, Ravi; Armenakis, Costas

    2016-06-01

    An approach for the co-registration of Digital Surface Models (DSMs) derived from Unmanned Aerial Vehicles (UAVs) and Terrestrial Laser Scanners (TLS) is proposed. Specifically, a wavelet-based feature descriptor for matching surface keypoints on the 2.5D DSMs is developed. DSMs are useful in wide-scope of various applications such as 3D building modelling and reconstruction, cultural heritage, urban and environmental planning, aircraft navigation/path routing, accident and crime scene reconstruction, mining as well as, topographic map revision and change detection. For these listed applications, it is not uncommon that there will be a need for automatically aligning multi-temporal DSMs which may have been acquired from multiple sensors, with different specifications over a period of time, and may have various overlaps. Terrestrial laser scanners usually capture urban facades in an accurate manner; however this is not the case for building roof structures. On the other hand, vertical photography from UAVs can capture the roofs. Therefore, the automatic fusion of UAV and laser-scanning based DSMs is addressed here as it serves various geospatial applications.

  13. Dynamic occlusion detection and inpainting of in situ captured terrestrial laser scanning point clouds sequence

    NASA Astrophysics Data System (ADS)

    Chen, Chi; Yang, Bisheng

    2016-09-01

    Laser point clouds captured using terrestrial laser scanning (TLS) in an uncontrollable urban outdoor or indoor scene suffer from irregular shaped data blanks caused by dynamic occlusion that temporarily exists, i.e., moving objects, such as pedestrians or cars, resulting in integrality and quality losses of the scene data. This paper proposes a novel automatic dynamic occlusion detection and inpainting method for sequential TLS point clouds captured from one scan position. In situ collected laser point clouds sequences are indexed by establishing a novel panoramic space partition that assigns a three dimensional voxel to each laser point according to the scanning setups. Then two stationary background models are constructed at the ray voxel level using the laser reflectance intensity and geometrical attributes of the point set inside each voxel across the TLS sequence. Finally, the background models are combined to detect the points on the dynamic object, and the ray voxels of the detected dynamic points are tracked for further inpainting by replacing the ray voxels with the corresponding background voxels from another scan. The resulting scene is free of dynamic occlusions. Experiments validated the effectiveness of the proposed method for indoor and outdoor TLS point clouds captured by a commercial terrestrial scanner. The proposed method achieves high precision and recall rate for dynamic occlusion detection and produces clean inpainted point clouds for further processing.

  14. A Two-Dimensional Laser Scanning Mirror Using Motion-Decoupling Electromagnetic Actuators

    PubMed Central

    Shin, Bu Hyun; Dongho, Oh; Lee, Seung-Yop

    2013-01-01

    This work proposes a two-dimensional (2-D) laser scanning mirror with a novel actuating structure composed of one magnet and two coils. The mirror-actuating device generates decoupled scanning motions about two orthogonal axes by combining two electromagnetic actuators of the conventional moving-coil and the moving-magnet types. We implement a finite element analysis to calculate magnetic flux in the electromagnetic system and experiments using a prototype with the overall size of 22 mm (W) × 20 mm (D) × 15 mm (H) for the mirror size of 8 mm × 8 mm. The upper moving-coil type actuator to rotate only the mirror part has the optical reflection angle of 15.7° at 10 Hz, 90°at the resonance frequency of 60 Hz at ±3V(±70mA) and the bandwidth of 91 Hz. The lowermoving-magnet type actuator has the optical reflection angle of 16.20°at 10 Hz and50°at the resonance frequency of 60 Hz at ±5V(±34mA) and the bandwidth of 88 Hz. The proposed compact and simple 2-D scanning mirror has advantages of large 2-D angular deflections, wide frequency bandwidth and low manufacturing cost. PMID:23535717

  15. Use of Naturally Available Reference Targets to Calibrate Airborne Laser Scanning Intensity Data

    PubMed Central

    Vain, Ants; Kaasalainen, Sanna; Pyysalo, Ulla; Krooks, Anssi; Litkey, Paula

    2009-01-01

    We have studied the possibility of calibrating airborne laser scanning (ALS) intensity data, using land targets typically available in urban areas. For this purpose, a test area around Espoonlahti Harbor, Espoo, Finland, for which a long time series of ALS campaigns is available, was selected. Different target samples (beach sand, concrete, asphalt, different types of gravel) were collected and measured in the laboratory. Using tarps, which have certain backscattering properties, the natural samples were calibrated and studied, taking into account the atmospheric effect, incidence angle and flying height. Using data from different flights and altitudes, a time series for the natural samples was generated. Studying the stability of the samples, we could obtain information on the most ideal types of natural targets for ALS radiometric calibration. Using the selected natural samples as reference, the ALS points of typical land targets were calibrated again and examined. Results showed the need for more accurate ground reference data, before using natural samples in ALS intensity data calibration. Also, the NIR camera-based field system was used for collecting ground reference data. This system proved to be a good means for collecting in situ reference data, especially for targets with inhomogeneous surface reflection properties. PMID:22574045

  16. Possibilities of a personal laser scanning system for forest mapping and ecosystem services.

    PubMed

    Liang, Xinlian; Kukko, Antero; Kaartinen, Harri; Hyyppä, Juha; Yu, Xiaowei; Jaakkola, Anttoni; Wang, Yunsheng

    2013-01-01

    A professional-quality, personal laser scanning (PLS) system for collecting tree attributes was demonstrated in this paper. The applied system, which is wearable by human operators, consists of a multi-constellation navigation system and an ultra-high-speed phase-shift laser scanner mounted on a rigid baseplate and consisting of a single sensor block. A multipass-corridor-mapping method was developed to process PLS data and a 2,000 m2 forest plot was utilized in the test. The tree stem detection accuracy was 82.6%; the root mean square error (RMSE) of the estimates of tree diameter at breast height (DBH) was 5.06 cm; the RMSE of the estimates of tree location was 0.38 m. The relative RMSE of the DBH estimates was 14.63%. The results showed, for the first time, the potential of the PLS system in mapping large forest plots. Further research on mapping accuracy in various forest conditions, data correction methods and multi-sensoral positioning techniques is needed. The utilization of this system in different applications, such as harvester operations, should also be explored. In addition to collecting tree-level and plot-level data for forest inventory, other possible applications of PLS for forest ecosystem services include mapping of canopy gaps, measuring leaf area index of large areas, documenting and visualizing forest routes feasible for recreation, hiking and berry and mushroom picking. PMID:24434879

  17. Wide-Area Mapping of Forest with National Airborne Laser Scanning and Field Inventory Datasets

    NASA Astrophysics Data System (ADS)

    Monnet, J.-M.; Ginzler, C.; Clivaz, J.-C.

    2016-06-01

    Airborne laser scanning (ALS) remote sensing data are now available for entire countries such as Switzerland. Methods for the estimation of forest parameters from ALS have been intensively investigated in the past years. However, the implementation of a forest mapping workflow based on available data at a regional level still remains challenging. A case study was implemented in the Canton of Valais (Switzerland). The national ALS dataset and field data of the Swiss National Forest Inventory were used to calibrate estimation models for mean and maximum height, basal area, stem density, mean diameter and stem volume. When stratification was performed based on ALS acquisition settings and geographical criteria, satisfactory prediction models were obtained for volume (R2 = 0.61 with a root mean square error of 47 %) and basal area (respectively 0.51 and 45 %) while height variables had an error lower than 19%. This case study shows that the use of nationwide ALS and field datasets for forest resources mapping is cost efficient, but additional investigations are required to handle the limitations of the input data and optimize the accuracy.

  18. Parallel Processing Method for Airborne Laser Scanning Data Using a PC Cluster and a Virtual Grid.

    PubMed

    Han, Soo Hee; Heo, Joon; Sohn, Hong Gyoo; Yu, Kiyun

    2009-01-01

    In this study, a parallel processing method using a PC cluster and a virtual grid is proposed for the fast processing of enormous amounts of airborne laser scanning (ALS) data. The method creates a raster digital surface model (DSM) by interpolating point data with inverse distance weighting (IDW), and produces a digital terrain model (DTM) by local minimum filtering of the DSM. To make a consistent comparison of performance between sequential and parallel processing approaches, the means of dealing with boundary data and of selecting interpolation centers were controlled for each processing node in parallel approach. To test the speedup, efficiency and linearity of the proposed algorithm, actual ALS data up to 134 million points were processed with a PC cluster consisting of one master node and eight slave nodes. The results showed that parallel processing provides better performance when the computational overhead, the number of processors, and the data size become large. It was verified that the proposed algorithm is a linear time operation and that the products obtained by parallel processing are identical to those produced by sequential processing. PMID:22574032

  19. Real time confocal laser scanning microscopy: Potential applications in space medicine and cell biology

    NASA Astrophysics Data System (ADS)

    Rollan, Ana; Ward, Thelma; McHale, Anthony P.

    Photodynamic therapy (PDT), in which tissues may be rendered fatally light-sensitive represents a relatively novel treatment for cancer and other disorders such as cardiovascular disease. It offers significant application to disease control in an isolated environment such as space flight. In studying PDT in the laboratory, low energy lasers such as HeNe lasers are used to activate the photosensitized cellular target. A major problem associated with these studies is that events occurring during actual exposure of the target cells to the system cannot be examined in real time. In this study HeLa cells were photosensitized and photodynamic activation was accomplished using the scanning microbeam from a confocal laser scanning microscope. This form of activation allowed for simultaneous photoactivation and observation and facilitated the recording of events at a microscopic level during photoactivation. Effects of photodynamic activation on the target cells were monitored using the fluorophores rhodamine 123 and ethidium homodimer-1. Potential applications of these forms of analyses to space medicine and cell biology are discussed.

  20. Quantification of chemotaxis during pediatric cardiac surgery by flow and laser scanning cytometry

    NASA Astrophysics Data System (ADS)

    Tarnok, Attila; Schmid, Joerg W.; Osmancik, Pavel; Lenz, Dominik; Pipek, Michal; Hambsch, Joerg; Gerstner, Andreas O.; Schneider, Peter

    2002-05-01

    Cardiac surgery with cardiopulmonary bypass (CPB) alters the leukocyte composition of the peripheral blood (PB). This response contributes to the sometimes adverse outcome with capillary leakage. Migration of activated cells to sites of inflammation, driven by chemokines is part of this response. In order to determine the chemotactic activity of patients serum during and after surgery we established an assay for PB leukocytes (PBL). PBL from healthy donors were isolated and 250,000 cells were placed into a migration chamber separated by a filter from a second lower chamber filled with patient serum. After incubation cells from top and bottom chamber were removed and stained with a cocktail of monoclonal antibodies for leukocyte subsets and analyzed on a flow cytometer (FCM). Cells at the bottom of the filter belong to the migrating compartment and were quantified by LSC after staining of nucleated cells. Increased chemotactic activity started at onset of anaesthesia followed by a phase of low activity immediately after surgery and a second phase of a high post-operative activity. The in vitro results correlated with results obtained by immunopenotyping of circulating PBL. Manipulation of the chemokine pattern might prove beneficial to prevent extravasation of cells leading to tissue damage. In chemotaxis assays with low amount of available serum the combined use of FCM and Laser Scanning LSC proved as an appropriate analytical tool.

  1. Modeling and simulation of protein uptake in cation exchanger visualized by confocal laser scanning microscopy.

    PubMed

    Yang, Kun; Shi, Qing-Hong; Sun, Yan

    2006-12-01

    Confocal laser scanning microscopy (CLSM) has been extensively applied in the area of protein chromatography to investigate the uptake mechanism of protein in adsorbents. However, due to the light attenuation in the deeper layers of a specimen, quantitative analysis using CLSM data is still far from reality. In this work, an attenuation equation for describing the darkening of the CLSM image in the deeper scanning layers was developed. Bovine serum albumin (BSA) adsorption to SP Sepharose FF was performed by batch adsorption and micro-column chromatography on which protein concentration in single absorbents were visualized by CLSM. The parameters in the equation were estimated by fitting it to the fluorescence intensity profiles obtained at adsorption equilibrium, and then the equation was used to simulate the effect caused by the light scattering and absorption. CLSM analysis demonstrated that BSA adsorption to SP Sepharose FF followed the shrinking core pattern and was predicted reasonably well by the pore diffusion model in combination with the attenuation equation. By comparison of the CLSM data with the simulations, it shows that the attenuation equation was useful to demonstrate the validity of an intraparticle mass transport model for the estimation of intraparticle protein concentration profiles. PMID:17034803

  2. Large-Eddy Simulation of Inhomogeneous Canopy Flows Using High Resolution Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Schlegel, Fabian; Stiller, Jörg; Bienert, Anne; Maas, Hans-Gerd; Queck, Ronald; Bernhofer, Christian

    2012-02-01

    The effect of sub-tree forest heterogeneity in the flow past a clearing is investigated by means of large-eddy simulation (LES). For this purpose, a detailed representation of the canopy has been acquired by terrestrial laser scanning for a patch of approximately 190 m length in the field site "Tharandter Wald", near the city of Dresden, Germany. The scanning data are used to produce a high resolution plant area distribution (PAD) that is averaged over approximately one tree height (30 m) along the transverse direction, in order to simplify the LES study. Despite the smoothing involved with this procedure, the resulting two-dimensional PAD maintains a rich vertical and horizontal structure. For the LES study, the PAD is embedded in a larger domain covered with an idealized, horizontally homogeneous canopy. Simulations are performed for neutral conditions and compared to a LES with homogeneous PAD and recent field measurements. The results reveal a considerable influence of small-scale plant distribution on the mean velocity field as well as on turbulence data. Particularly near the edges of the clearing, where canopy structure is highly variable, usage of a realistic PAD appears to be crucial for capturing the local flow structure. Inside the forest, local variations in plant density induce a complex pattern of upward and downward motions, which remain visible in the mean flow and make it difficult to identify the "adjustment zone" behind the windward edge of the clearing.

  3. The fluvial sediment budget of the proglacial Fagge River derived from repeated laser scanning surveys

    NASA Astrophysics Data System (ADS)

    Morche, D.; Bryk, A.; Baewert, H.

    2013-12-01

    Alpine regions are strongly affected by the global climate change. Alpine glaciers have had a negative net balance since the end of the Little Ice Age (LIA). Proglacial areas with freshly exposed subglacial sediments are expanding due to the retreat of glaciers. These sediments (moraines, tills, glaciofluvial deposits, etc.) are unconsolidated, unvegetated and are therefore highly unstable. During heavy rainfall events, glacial and glaciofluvial deposits are often remobilized and transported down the fluvial system. This study is focused on rapidly changing surfaces in the proglacial fluvial system of the Fagge River, which drains the Gepatschferner, one of the largest glaciers in Austria. . The field site is located in the Kaunertal/Austria and covers an area from the snout of the glacier (2206 m a.s.l.) to the outlet of the Fagge River at the Gepatsch Reservoir at (1750 m a.s.l.). The main goals of this study are to measure surface changes and calculate mass balances of major sediment sources (alluvial plains, bars) in the proglacial area that are directly connected to the fluvial system. Towards this end, multiple terrestrial laser scans were performed with an Optech ILRIS-36D laser scanner during the field season in 2011 and 2012. Significant surface changes occurred during the investigation period, mainly caused by an extreme flood event occurred after heavy rain on August 26, 2012. Large amounts of sediment (>70000 m^3) were remobilized, especially in the upper parts of the proglacial area, and were redeposited further downstream during this extraordinary event.

  4. Through-water terrestrial laser scanning of gravel beds at the plot scale: a preliminary investigation

    NASA Astrophysics Data System (ADS)

    Smith, M. W.; Vericat, D.; Gibbins, C. G.

    2010-12-01

    Natural gravel surfaces are spatially variable. Measurement of their detailed structure is essential for understanding the interaction of roughness with near-bed flows and the sediment entrainment process. However, the acquisition of high resolution topographic data of a river bed is technically demanding where the bed is not regularly exposed by fluctuating water levels. Often the most geomorphologically active portion of a gravel bed river remains submerged even at low stages. Optical reflectance depth monitoring and through-water photogrammetry have been employed to map bed topography over relatively shallow submerged zones. This study presents laboratory and field experiments to demonstrate that through-water terrestrial laser scanning can also be used to provide high resolution DTMs of submerged gravel beds. The resulting point cloud data must be corrected for refraction before the registration process takes place. Additional errors arise from the internal architecture of the scanner as the offset between the arbitrary origin and the point from which the laser emanates must be calculated before refraction correction. These DTMs can be seamlessly embedded within larger sub aerial reach-scale surveys and can be acquired alongside flow measurements to examine the effects of three-dimensional surface geometry on turbulent flow fields.

  5. In vivo assessment of the structure of skin microcirculation by reflectance confocal-laser-scanning microscopy

    NASA Astrophysics Data System (ADS)

    Sugata, Keiichi; Osanai, Osamu; Kawada, Hiromitsu

    2012-02-01

    One of the major roles of the skin microcirculation is to supply oxygen and nutrition to the surrounding tissue. Regardless of the close relationship between the microcirculation and the surrounding tissue, there are few non-invasive methods that can evaluate both the microcirculation and its surrounding tissue at the same site. We visualized microcapillary plexus structures in human skin using in vivo reflectance confocal-laser-scanning microscopy (CLSM), Vivascope 3000® (Lucid Inc., USA) and Image J software (National Institutes of Health, USA) for video image processing. CLSM is a non-invasive technique that can visualize the internal structure of the skin at the cellular level. In addition to internal morphological information such as the extracellular matrix, our method reveals capillary structures up to the depth of the subpapillary plexus at the same site without the need for additional optical systems. Video images at specific depths of the inner forearm skin were recorded. By creating frame-to-frame difference images from the video images using off-line video image processing, we obtained images that emphasize the brightness depending on changes of intensity coming from the movement of blood cells. Merging images from different depths of the skin elucidates the 3-dimensional fine line-structure of the microcirculation. Overall our results show the feasibility of a non-invasive, high-resolution imaging technique to characterize the skin microcirculation and the surrounding tissue.

  6. 3D Laser Scanning Modeling and Application on Dazu Thousand-hand Bodhisattva in China

    NASA Astrophysics Data System (ADS)

    Hou, M.; Zhang, X.; Wu, Y.; Hu, Y.

    2014-04-01

    The Dazu Thousand-hand Bodhisattva Statue is located at Baoding Mountain in Chongqing. It has the reputation as "the Gem of World's Rock Carving Art". At present,the Dazu Thousand-hand Bodhisattva Statue is basically well conserved, while the local damage is already very serious. However, the Dazu Thousand-hand Bodhisattva Statue is a three-dimensional caved statue, the present plane surveying and mapping device cannot reflect the preservation situation completely. Therefore, the documentation of the Dazu Thousand-hand Bodhisattva Statue using terrestrial laser scanning is of great significance. This paper will introduce a new method for superfine 3D modeling of Thousand-hand Bodhisattva based on the high-resolution 3D cloud points. By analyzing these 3D cloud points and 3D models, some useful information, such as several 3D statistics, 3D thematic map and 3D shape restoration suggestion of Thousand-hand Bodhisattva will be revealed, which are beneficial to restoration work and some other application.

  7. A novel near real-time laser scanning device for geometrical determination of pleural cavity surface

    NASA Astrophysics Data System (ADS)

    Kim, Michele M.; Zhu, Timothy C.

    2013-03-01

    During HPPH-mediated pleural photodynamic therapy (PDT), it is critical to determine the anatomic geometry of the pleural surface quickly as there may be movement during treatment resulting in changes with the cavity. We have developed a laser scanning device for this purpose, which has the potential to obtain the surface geometry in real-time. A red diode laser with a holographic template to create a pattern and a camera with auto-focusing abilities are used to scan the cavity. In conjunction with a calibration with a known surface, we can use methods of triangulation to reconstruct the surface. Using a chest phantom, we are able to obtain a 360 degree scan of the interior in under 1 minute. The chest phantom scan was compared to an existing CT scan to determine its accuracy. The laser-camera separation can be determined through the calibration with 2mm accuracy. The device is best suited for environments that are on the scale of a chest cavity (between 10cm and 40cm). This technique has the potential to produce cavity geometry in real-time during treatment. This would enable PDT treatment dosage to be determined with greater accuracy. Works are ongoing to build a miniaturized device that moves the light source and camera via a fiber-optics bundle commonly used for endoscopy with increased accuracy.

  8. Evaluation of Wavelet Denoising Methods for Small-Scale Joint Roughness Estimation Using Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Bitenc, M.; Kieffer, D. S.; Khoshelham, K.

    2015-08-01

    The precision of Terrestrial Laser Scanning (TLS) data depends mainly on the inherent random range error, which hinders extraction of small details from TLS measurements. New post processing algorithms have been developed that reduce or eliminate the noise and therefore enable modelling details at a smaller scale than one would traditionally expect. The aim of this research is to find the optimum denoising method such that the corrected TLS data provides a reliable estimation of small-scale rock joint roughness. Two wavelet-based denoising methods are considered, namely Discrete Wavelet Transform (DWT) and Stationary Wavelet Transform (SWT), in combination with different thresholding procedures. The question is, which technique provides a more accurate roughness estimates considering (i) wavelet transform (SWT or DWT), (ii) thresholding method (fixed-form or penalised low) and (iii) thresholding mode (soft or hard). The performance of denoising methods is tested by two analyses, namely method noise and method sensitivity to noise. The reference data are precise Advanced TOpometric Sensor (ATOS) measurements obtained on 20 × 30 cm rock joint sample, which are for the second analysis corrupted by different levels of noise. With such a controlled noise level experiments it is possible to evaluate the methods' performance for different amounts of noise, which might be present in TLS data. Qualitative visual checks of denoised surfaces and quantitative parameters such as grid height and roughness are considered in a comparative analysis of denoising methods. Results indicate that the preferred method for realistic roughness estimation is DWT with penalised low hard thresholding.

  9. Roof Reconstruction from Airborne Laser Scanning Data Based on Image Processing Methods

    NASA Astrophysics Data System (ADS)

    Goebbels, S.; Pohle-Fröhlich, R.

    2016-06-01

    The paper presents a new data-driven approach to generate CityGML building models from airborne laser scanning data. The approach is based on image processing methods applied to an interpolated height map and avoids shortcomings of established methods for plane detection like Hough transform or RANSAC algorithms on point clouds. The improvement originates in an interpolation algorithm that generates a height map from sparse point cloud data by preserving ridge lines and step edges of roofs. Roof planes then are detected by clustering the height map's gradient angles, parameterizations of planes are estimated and used to filter out noise around ridge lines. On that basis, a raster representation of roof facets is generated. Then roof polygons are determined from region outlines, connected to a roof boundary graph, and simplified. Whereas the method is not limited to churches, the method's performance is primarily tested for church roofs of the German city of Krefeld because of their complexity. To eliminate inaccuracies of spires, contours of towers are detected additionally, and spires are rendered as solids of revolution. In our experiments, the new data-driven method lead to significantly better building models than the previously applied model-driven approach.

  10. Applicability of confocal laser scanning microscopy for evaluation and monitoring of cutaneous wound healing

    NASA Astrophysics Data System (ADS)

    Lange-Asschenfeldt, Susanne; Bob, Adrienne; Terhorst, Dorothea; Ulrich, Martina; Fluhr, Joachim; Mendez, Gil; Roewert-Huber, Hans-Joachim; Stockfleth, Eggert; Lange-Asschenfeldt, Bernhard

    2012-07-01

    There is a high demand for noninvasive imaging techniques for wound assessment. In vivo reflectance confocal laser scanning microscopy (CLSM) represents an innovative optical technique for noninvasive evaluation of normal and diseased skin in vivo at near cellular resolution. This study was designed to test the feasibility of CLSM for noninvasive analysis of cutaneous wound healing in 15 patients (7 male/8 female), including acute and chronic, superficial and deep dermal skin wounds. A commercially available CLSM system was used for the assessment of wound bed and wound margins in order to obtain descriptive cellular and morphological parameters of cutaneous wound repair noninvasively and over time. CLSM was able to visualize features of cutaneous wound repair in epidermal and superficial dermal wounds, including aspects of inflammation, neovascularisation, and tissue remodelling in vivo. Limitations include the lack of mechanic fixation of the optical system on moist surfaces restricting the analysis of chronic skin wounds to the wound margins, as well as a limited optical resolution in areas of significant slough formation. By describing CLSM features of cutaneous inflammation, vascularisation, and epithelialisation, the findings of this study support the role of CLSM in modern wound research and management.

  11. Urban Road Detection in Airbone Laser Scanning Point Cloud Using Random Forest Algorithm

    NASA Astrophysics Data System (ADS)

    Kaczałek, B.; Borkowski, A.

    2016-06-01

    The objective of this research is to detect points that describe a road surface in an unclassified point cloud of the airborne laser scanning (ALS). For this purpose we use the Random Forest learning algorithm. The proposed methodology consists of two stages: preparation of features and supervised point cloud classification. In this approach we consider ALS points, representing only the last echo. For these points RGB, intensity, the normal vectors, their mean values and the standard deviations are provided. Moreover, local and global height variations are taken into account as components of a feature vector. The feature vectors are calculated on a basis of the 3D Delaunay triangulation. The proposed methodology was tested on point clouds with the average point density of 12 pts/m2 that represent large urban scene. The significance level of 15% was set up for a decision tree of the learning algorithm. As a result of the Random Forest classification we received two subsets of ALS points. One of those groups represents points belonging to the road network. After the classification evaluation we achieved from 90% of the overall classification accuracy. Finally, the ALS points representing roads were merged and simplified into road network polylines using morphological operations.

  12. Processing of materials of laser scanning of roads on the basis of recursive cubic splines

    NASA Astrophysics Data System (ADS)

    Esharov, E. A.; Shumilov, B. M.

    2015-01-01

    The problem of approximation of discrete dependence (ti, yi) by means of continuous function f(t) arises in tasks of the analysis and data processing of measurements yi at successive time points of ti. The solution of the presented task becomes significantly complicated in cases when measurements form a continuous stream, and the results of processing are required to be used before full reception of measurements. The computational schemes based on recurrent spline of degree 3 depths 1 and 2 which provide accuracy for polynomials of the third degree were used in the work. The main results consist in elaboration of mathematical formulas and the proof of stability of the constructed computing schemes. Relevance of the work consists in possibility of application of the constructed splines, for example, for processing materials of laser scanning of roads. Advantages of the constructed splines are the piecewise cubic character of the recovering of the simulated smooth spatial curve and possibility of nonuniform sampling on the route when the quantity of spline knots are less than the number of samples of a function. Examples of calculation of parameters of computing schemes, and also results of numerical experiments are presented.

  13. A direct method for measuring mouse capillary cortical blood volume using multiphoton laser scanning microscopy.

    PubMed

    Vérant, Pascale; Serduc, Raphaël; Van Der Sanden, Boudewijn; Rémy, Chantal; Vial, Jean-Claude

    2007-05-01

    Knowledge of the blood volume per unit volume of brain tissue is important for understanding brain function in health and disease. We describe a direct method using two-photon laser scanning microscopy to obtain in vivo the local capillary blood volume in the cortex of anesthetized mouse. We infused fluorescent dyes in the circulating blood and imaged the blood vessels, including the capillaries, to a depth of 600 microm below the dura at the brain surface. Capillary cortical blood volume (CCBV) was calculated without any form recognition and segmentation, by normalizing the total fluorescence measured at each depth and integrating the collected intensities all over the stack. Theoretical justifications are presented and numerical simulations were performed to validate this method which was weakly sensitive to background noise. Then, CCBV had been estimated on seven healthy mice between 2%+/-0.3% and 2.4%+/-0.4%. We showed that this measure of CCBV is reproductible and that this method is highly sensitive to the explored zones in the cortex (vessel density and size). This method, which dispenses with form recognition, is rapid and would allow to study in vivo temporal and highly resolute spatial variations of CCBV under different conditions or stimulations. PMID:17063147

  14. Multidimensional Laser Scanning System for Underwater Mapping of Small Structures and Bottom Topography

    NASA Astrophysics Data System (ADS)

    Fuchs, E.

    2005-05-01

    A multidimensional laser scanning imaging system is under development to investigate new concepts in underwater imaging. The system is a modification of the 3D Laser Imaging & Tracking Electro-optical System (3D LITES; HBOI, patent # 5,418,608) that was developed for 3D mapping applications in biological oceanography. The new 3D-FLITES ("F" stands for added Fluorescence capability) captures both spatial and spectral data and offers extended operation capabilities. The system can capture the range to each pixel in the sensor's field of view, the relative reflectance of each pixel (similar to "conventional" images) and five channels of fluorescence emission in the scene, captured sequentially. Multidimensional data sets can be instrumental in bottom topography mapping and object identification. The 3D FLITES has the unique capability to operate in user-selectable line or raster scanning modes if mounted on a moving platform. In raster mode two perpendicular mirrors are driven, allowing the operator to capture single frames (capturing either reflectance or fluorescence data) or a stream of images in fast rate (16 frames per second). With this operational flexibility the operator can combine a "fly over" scanning mode with "look ahead", "look sideways" and "zoom" modes. The current system is limited in range and resolution; nevertheless it can serve as a test-bed to evaluate operational parameters, data acquisition and signal processing protocols that could lead to a smaller, more efficient system in the future.

  15. Automated analysis of barley organs using 3D laser scanning: an approach for high throughput phenotyping.

    PubMed

    Paulus, Stefan; Dupuis, Jan; Riedel, Sebastian; Kuhlmann, Heiner

    2014-01-01

    Due to the rise of laser scanning the 3D geometry of plant architecture is easy to acquire. Nevertheless, an automated interpretation and, finally, the segmentation into functional groups are still difficult to achieve. Two barley plants were scanned in a time course, and the organs were separated by applying a histogram-based classification algorithm. The leaf organs were represented by meshing algorithms, while the stem organs were parameterized by a least-squares cylinder approximation. We introduced surface feature histograms with an accuracy of 96% for the separation of the barley organs, leaf and stem. This enables growth monitoring in a time course for barley plants. Its reliability was demonstrated by a comparison with manually fitted parameters with a correlation R(2) = 0:99 for the leaf area and R(2) = 0:98 for the cumulated stem height. A proof of concept has been given for its applicability for the detection of water stress in barley, where the extension growth of an irrigated and a non-irrigated plant has been monitored. PMID:25029283

  16. Automatic Registration of Terrestrial Laser Scanning Point Clouds using Panoramic Reflectance Images

    PubMed Central

    Kang, Zhizhong; Li, Jonathan; Zhang, Liqiang; Zhao, Qile; Zlatanova, Sisi

    2009-01-01

    This paper presents a new approach to the automatic registration of terrestrial laser scanning (TLS) point clouds using panoramic reflectance images. The approach follows a two-step procedure that includes both pair-wise registration and global registration. The pair-wise registration consists of image matching (pixel-to-pixel correspondence) and point cloud registration (point-to-point correspondence), as the correspondence between the image and the point cloud (pixel-to-point) is inherent to the reflectance images. False correspondences are removed by a geometric invariance check. The pixel-to-point correspondence and the computation of the rigid transformation parameters (RTPs) are integrated into an iterative process that allows for the pair-wise registration to be optimised. The global registration of all point clouds is obtained by a bundle adjustment using a circular self-closure constraint. Our approach is tested with both indoor and outdoor scenes acquired by a FARO LS 880 laser scanner with an angular resolution of 0.036° and 0.045°, respectively. The results show that the pair-wise and global registration accuracies are of millimetre and centimetre orders, respectively, and that the process is fully automatic and converges quickly. PMID:22574036

  17. A diffraction-limited scanning system providing broad spectral range for laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Yu, Jiun-Yann; Liao, Chien-Sheng; Zhuo, Zong-Yan; Huang, Chen-Han; Chui, Hsiang-Chen; Chu, Shi-Wei

    2009-11-01

    Diversified research interests in scanning laser microscopy nowadays require broadband capability of the optical system. Although an all-mirror-based optical design with a suitable metallic coating is appropriate for broad-spectrum applications from ultraviolet to terahertz, most researchers prefer lens-based scanning systems despite the drawbacks of a limited spectral range, ghost reflection, and chromatic aberration. One of the main concerns is that the geometrical aberration induced by off-axis incidence on spherical mirrors significantly deteriorates image resolution. Here, we demonstrate a novel geometrical design of a spherical-mirror-based scanning system in which off-axis aberrations, both astigmatism and coma, are compensated to reach diffraction-limited performance. We have numerically simulated and experimentally verified that this scanning system meets the Marechà l condition and provides high Strehl ratio within a 3°×3° scanning area. Moreover, we demonstrate second-harmonic-generation imaging from starch with our new design. A greatly improved resolution compared to the conventional mirror-based system is confirmed. This scanning system will be ideal for high-resolution linear/nonlinear laser scanning microscopy, ophthalmoscopic applications, and precision fabrications.

  18. Virtual Reconstruction of the Almaqah Temple of Yeha in Ethiopia by Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Lindstaedt, M.; Mechelke, K.; Schnelle, M.; Kersten, Th.

    2011-09-01

    In autumn 2009 the Almaqah Temple of Yeha in Ethiopia has been recorded by terrestrial laser scanning and digital photogrammetry in cooperation between the Sana'a Branch of the Orient Department of the German Archaeological Institute and the HafenCity University Hamburg. The temple dates from the 7th Century BC and is one of the best preserved buildings of Sabaean architecture in Africa. As a basis for all future project works a geodetic network was established in UTM-coordinates by GPS measurements. The geodata collected will form the basis for all future work on the temple. The deformations of the facades were determined for restoration issues and the existing parts of the temple were modelled by meshing (3D triangulation). Using the scanned point cloud and a technical analysis of the building the Propylon, which is no longer existent today, was virtually reconstructed. In future, the data will also be included in the master plan for touristic development of the region of Axum and Yeha in northern Ethiopia.

  19. a Semi-Automatic Procedure for Texturing of Laser Scanning Point Clouds with Google Streetview Images

    NASA Astrophysics Data System (ADS)

    Lichtenauer, J. F.; Sirmacek, B.

    2015-08-01

    We introduce a method to texture 3D urban models with photographs that even works for Google Streetview images and can be done with currently available free software. This allows realistic texturing, even when it is not possible or cost-effective to (re)visit a scanned site to take textured scans or photographs. Mapping a photograph onto a 3D model requires knowledge of the intrinsic and extrinsic camera parameters. The common way to obtain intrinsic parameters of a camera is by taking several photographs of a calibration object with a priori known structure. The extra challenge of using images from a database such as Google Streetview, rather than your own photographs, is that it does not allow for any controlled calibration. To overcome this limitation, we propose to calibrate the panoramic viewer of Google Streetview using Structure from Motion (SfM) on any structure of which Google Streetview offers views from multiple angles. After this, the extrinsic parameters for any other view can be calculated from 3 or more tie points between the image from Google Streetview and a 3D model of the scene. These point correspondences can either be obtained automatically or selected by manual annotation. We demonstrate how this procedure provides realistic 3D urban models in an easy and effective way, by using it to texture a publicly available point cloud from a terrestrial laser scan made in Bremen, Germany, with a screenshot from Google Streetview, after estimating the focal length from views from Paris, France.

  20. Towards Automatic Single-Sensor Mapping by Multispectral Airborne Laser Scanning

    NASA Astrophysics Data System (ADS)

    Ahokas, E.; Hyyppä, J.; Yu, X.; Liang, X.; Matikainen, L.; Karila, K.; Litkey, P.; Kukko, A.; Jaakkola, A.; Kaartinen, H.; Holopainen, M.; Vastaranta, M.

    2016-06-01

    This paper describes the possibilities of the Optech Titan multispectral airborne laser scanner in the fields of mapping and forestry. Investigation was targeted to six land cover classes. Multispectral laser scanner data can be used to distinguish land cover classes of the ground surface, including the roads and separate road surface classes. For forest inventory using point cloud metrics and intensity features combined, total accuracy of 93.5% was achieved for classification of three main boreal tree species (pine, spruce and birch).When using intensity features - without point height metrics - a classification accuracy of 91% was achieved for these three tree species. It was also shown that deciduous trees can be further classified into more species. We propose that intensity-related features and waveform-type features are combined with point height metrics for forest attribute derivation in area-based prediction, which is an operatively applied forest inventory process in Scandinavia. It is expected that multispectral airborne laser scanning can provide highly valuable data for city and forest mapping and is a highly relevant data asset for national and local mapping agencies in the near future.

  1. Application of Laser Scanning Confocal Microscopy to Heat and Mass Transport Modeling in Porous Microstructures

    NASA Technical Reports Server (NTRS)

    Marshall, Jochen; Milos, Frank; Fredrich, Joanne; Rasky, Daniel J. (Technical Monitor)

    1997-01-01

    Laser Scanning Confocal Microscopy (LSCM) has been used to obtain digital images of the complicated 3-D (three-dimensional) microstructures of rigid, fibrous thermal protection system (TPS) materials. These orthotropic materials are comprised of refractory ceramic fibers with diameters in the range of 1 to 10 microns and have open porosities of 0.8 or more. Algorithms are being constructed to extract quantitative microstructural information from the digital data so that it may be applied to specific heat and mass transport modeling efforts; such information includes, for example, the solid and pore volume fractions, the internal surface area per volume, fiber diameter distributions, and fiber orientation distributions. This type of information is difficult to obtain in general, yet it is directly relevant to many computational efforts which seek to model macroscopic thermophysical phenomena in terms of microscopic mechanisms or interactions. Two such computational efforts for fibrous TPS materials are: i) the calculation of radiative transport properties; ii) the modeling of gas permeabilities.

  2. Assessment of relative accuracy of AHN-2 laser scanning data using planar features.

    PubMed

    van der Sande, Corné; Soudarissanane, Sylvie; Khoshelham, Kourosh

    2010-01-01

    AHN-2 is the second part of the Actueel Hoogtebestand Nederland project, which concerns the acquisition of high-resolution altimetry data over the entire Netherlands using airborne laser scanning. The accuracy assessment of laser altimetry data usually relies on comparing corresponding tie elements, often points or lines, in the overlapping strips. This paper proposes a new approach to strip adjustment and accuracy assessment of AHN-2 data by using planar features. In the proposed approach a transformation is estimated between two overlapping strips by minimizing the distances between points in one strip and their corresponding planes in the other. The planes and the corresponding points are extracted in an automated segmentation process. The point-to-plane distances are used as observables in an estimation model, whereby the parameters of a transformation between the two strips and their associated quality measures are estimated. We demonstrate the performance of the method for the accuracy assessment of the AHN-2 dataset over Zeeland province of The Netherlands. The results show vertical offsets of up to 4 cm between the overlapping strips, and horizontal offsets ranging from 2 cm to 34 cm. PMID:22163650

  3. Use of naturally available reference targets to calibrate airborne laser scanning intensity data.

    PubMed

    Vain, Ants; Kaasalainen, Sanna; Pyysalo, Ulla; Krooks, Anssi; Litkey, Paula

    2009-01-01

    We have studied the possibility of calibrating airborne laser scanning (ALS) intensity data, using land targets typically available in urban areas. For this purpose, a test area around Espoonlahti Harbor, Espoo, Finland, for which a long time series of ALS campaigns is available, was selected. Different target samples (beach sand, concrete, asphalt, different types of gravel) were collected and measured in the laboratory. Using tarps, which have certain backscattering properties, the natural samples were calibrated and studied, taking into account the atmospheric effect, incidence angle and flying height. Using data from different flights and altitudes, a time series for the natural samples was generated. Studying the stability of the samples, we could obtain information on the most ideal types of natural targets for ALS radiometric calibration. Using the selected natural samples as reference, the ALS points of typical land targets were calibrated again and examined. Results showed the need for more accurate ground reference data, before using natural samples in ALS intensity data calibration. Also, the NIR camera-based field system was used for collecting ground reference data. This system proved to be a good means for collecting in situ reference data, especially for targets with inhomogeneous surface reflection properties. PMID:22574045

  4. Combined Use of Terrestrial Laser Scanning and IR Thermography Applied to a Historical Building

    PubMed Central

    Costanzo, Antonio; Minasi, Mario; Casula, Giuseppe; Musacchio, Massimo; Buongiorno, Maria Fabrizia

    2015-01-01

    The conservation of architectural heritage usually requires a multidisciplinary approach involving a variety of specialist expertise and techniques. Nevertheless, destructive techniques should be avoided, wherever possible, in order to preserve the integrity of the historical buildings, therefore the development of non-destructive and non-contact techniques is extremely important. In this framework, a methodology for combining the terrestrial laser scanning and the infrared thermal images is proposed, in order to obtain a reconnaissance of the conservation state of a historical building. The proposed case study is represented by St. Augustine Monumental Compound, located in the historical centre of the town of Cosenza (Calabria, South Italy). Adopting the proposed methodology, the paper illustrates the main results obtained for the building test overlaying and comparing the collected data with both techniques, in order to outline the capabilities both to detect the anomalies and to improve the knowledge on health state of the masonry building. The 3D model, also, allows to provide a reference model, laying the groundwork for implementation of a monitoring multisensor system based on the use of non-destructive techniques. PMID:25609042

  5. Combining terrestrial laser scanning and physical modelling experiments to characterise the structure and drag of vegetation.

    NASA Astrophysics Data System (ADS)

    Vasilopoulos, Grigorios; Leyland, Julian; Nield, Joanna

    2016-04-01

    Vegetation affects flow and, because of its ubiquity in nature, plays a significant role in modulating geomorphic change. Plants function as large-scale obstacles that exert additional drag on water flows. The vegetative drag applied is a function of the structure and configuration of the plant and these attributes influence both local scale turbulence and the structure of the boundary layer. Whilst several approaches have been developed to describe the relationship between plant structure and drag, such as using bulk parameters, geometric analogies or porous medium approaches, they have previously failed to accurately and precisely characterise the vegetation itself. Terrestrial Laser Scanning (TLS) has the ability to capture structures and forms in 3D with high resolution, precision and accuracy, which provides an opportunity to accurately describe vegetation structure. However, TLS data are essentially an aggregate of dimensionless points in space and the complexity of vegetation biomass means that some of the measured points are erroneous. A method has been developed that is capable of accurately characterising vegetation structure in 3D from dense TLS point cloud data, using a porosity approach. The corresponding fluvial drag of the vegetation is measured in a flume, using a bulk roughness function calculated from precise measurements of water surface slope and a series of high resolution acoustic Doppler velocimetry (ADV) measurements. A series of structurally variable plants were characterised using the methods outlined above and the results are presented herein.

  6. Inspection of float glass using a novel retroreflective laser scanning system

    NASA Astrophysics Data System (ADS)

    Holmes, Jonathan D.

    1997-07-01

    Since 1988, Image Automation has marketed a float glass inspection system using a novel retro-reflective laser scanning system. The (patented) instrument scans a laser beam by use of a polygon through the glass onto a retro-reflective screen, and collects the retro-reflected light off the polygon, such that a stationary image of the moving spot on the screen is produced. The spot image is then analyzed for optical effects introduced by defects within the glass, which typically distort and attenuate the scanned laser beam, by use of suitable detectors. The inspection system processing provides output of defect size, shape and severity, to the factory network for use in rejection or sorting of glass plates to the end customer. This paper briefly describes the principles of operation, the system architecture, and limitations to sensitivity and measurement repeatability. New instruments based on the retro-reflective scanning method have recently been developed. The principles and implementation are described. They include: (1) Simultaneous detection of defects within the glass and defects in a mirror coating on the glass surface using polarized light. (2) A novel distortion detector for very dark glass. (3) Measurement of optical quality (flatness/refractive homogeneity) of the glass using a position sensitive detector.

  7. Confocal laser-scanning microscopy of capillaries in normal and psoriatic skin

    NASA Astrophysics Data System (ADS)

    Archid, Rami; Patzelt, Alexa; Lange-Asschenfeldt, Bernhard; Ahmad, Sufian S.; Ulrich, Martina; Stockfleth, Eggert; Philipp, Sandra; Sterry, Wolfram; Lademann, Juergen

    2012-10-01

    An important and most likely active role in the pathogenesis of psoriasis has been attributed to changes in cutaneous blood vessels. The purpose of this study was to use confocal laser-scanning microscopy (CLSM) to investigate dermal capillaries in psoriatic and normal skin. The structures of the capillary loops in 5 healthy participants were compared with those in affected skin of 13 psoriasis patients. The diameters of the capillaries and papillae were measured for each group with CLSM. All investigated psoriasis patients showed elongated, widened, and tortuous microvessels in the papillary dermis, whereas all healthy controls showed a single capillary loop in each dermal papilla. The capillaries of the papillary loop and the dermal papilla were significantly enlarged in the psoriatic skin lesions (diameters 24.39±2.34 and 146.46±28.52 μm, respectively) in comparison to healthy skin (diameters 9.53±1.8 and 69.48±17.16 μm, respectively) (P<0.001). CLSM appears to represent a promising noninvasive technique for evaluating dermal capillaries in patients with psoriasis. The diameter of the vessels could be seen as a well-quantifiable indicator for the state of psoriatic skin. CLSM could be useful for therapeutic monitoring to delay possible recurrences.

  8. Determination of the thickness and structure of the skin barrier by in vivo laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Lademann, J.; Richter, H.; Astner, S.; Patzelt, A.; Knorr, F.; Sterry, W.; Antoniou, Ch

    2008-04-01

    Normal skin barrier function is an essential aspect of skin homeostasis and regeneration. Dynamic inflammatory, proliferative and neoplastic skin processes such as wound healing, psoriasis and contact dermatitis are associated with a significant disruption of the skin barrier. In recent years, there has been increasing interest in evaluating cosmetic and pharmacologic products for their ability to restore these protective properties. The gold standard for characterization of barrier function has been the measurement of the transepidermal water loss, however the disadvantage of this method is its interference with several endogenous and exogenous factors such as hydration, perspiration and topically applied substances. This study was aimed to test the clinical applicability of a fluorescence confocal laser scanning microscope (LSM) for a systematic morphologic analysis of the structure, integrity and thickness of the stratum corneum in 10 otherwise healthy volunteers. The influence of skin treatment with commercial moisturizing cream on skin barrier function was evaluated in serial non-invasive examinations. Our findings showed that in vivo LSM may represent a simple and efficient method for the characterization of skin barrier properties, such as the thickness and hydration of the stratum corneum.

  9. Detecting pruning of individual stems using Airborne Laser Scanning data captured from an Unmanned Aerial Vehicle

    NASA Astrophysics Data System (ADS)

    Wallace, Luke; Watson, Christopher; Lucieer, Arko

    2014-08-01

    Modern forest management involves implementing optimal pruning regimes. These regimes aim to achieve the highest quality timber in the shortest possible rotation period. Although a valuable addition to forest management activities, tracking the application of these treatments in the field to ensure best practice management is not economically viable. This paper describes the use of Airborne Laser Scanner (ALS) data to track the rate of pruning in a Eucalyptus globulus stand. Data is obtained from an Unmanned Aerial Vehicle (UAV) and we describe automated processing routines that provide a cost-effective alternative to field sampling. We manually prune a 500 m2 plot to 2.5 m above the ground at rates of between 160 and 660 stems/ha. Utilising the high density ALS data, we first derived crown base height (CBH) with an RMSE of 0.60 m at each stage of pruning. Variability in the measurement of CBH resulted in both false positive (mean rate of 11%) and false negative detection (3.5%), however, detected rates of pruning of between 96% and 125% of the actual rate of pruning were achieved. The successful automated detection of pruning within this study highlights the suitability of UAV laser scanning as a cost-effective tool for monitoring forest management activities.

  10. Elastomeric photo-actuators and their investigation by confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Czaniková, Klaudia; Ilčíková, Markéta; Krupa, Igor; Mičušík, Matej; Kasák, Peter; Pavlova, Ewa; Mosnáček, Jaroslav; Chorvát, Dušan, Jr.; Omastová, Mária

    2013-10-01

    The photo-actuation behavior of nanocomposites based on ethylene-vinylacetate copolymer (EVA) and styrene-isoprene-styrene (SIS) block copolymer filled with well-dispersed and modified multiwalled carbon nanotubes (MWCNTs) is discussed in this paper. The nanocomposites were prepared by casting from solution. To improve the dispersion of the MWCNTs in EVA, the MWCNT surface was modified with a non-covalent surfactant, cholesteryl 1-pyrenecarboxylate (PyChol). To prepare SIS nanocomposites, the MWCNT surface was covalently modified with polystyrene chains. The good dispersion of the filler was confirmed by transmission electron microscopy (TEM). Special, custom-made punch/die molds were used to create a Braille element (BE)-like shape, which under shear forces induces a uniaxial orientation of the MWCNTs within the matrix. The uniaxial orientation of MWCNTs is an essential precondition to ensure the photo-actuating behavior of MWCNTs in polymeric matrices. The orientation of the MWCNTs within the matrices was examined by scanning electron microscopy (SEM). Nanocomposite BEs were illuminated from the bottom by a red light-emitting diode (LED), and the photo-actuation was investigated by confocal laser scanning microscopy (CLSM). When the BEs were exposed to light, a temporary increase in the height of the element was detected. This process was observed to be reversible: after switching off the light, the BEs returned to their original shape and height.

  11. Improved Correction Method for Water-Refracted Terrestrial Laser Scanning Data Acquired in the Mountain Channel

    NASA Astrophysics Data System (ADS)

    Miura, N.; Asano, Y.; Moribe, Y.

    2016-06-01

    Detailed information of underwater topography is required for better understanding and prediction of water and sediment transport in a mountain channel. Recent research showed promising utility of green-wavelength Terrestrial Laser Scanning (TLS) for measuring submerged stream-bed structure in fluvial environment. However, difficulty in acquiring reliable underwater data has been remained in the part of mountain channel where water surface has some gradient. Since horizontal water surface was a major premise for the existing water refraction correction method, significant error was resulted in such area. Therefore, this paper presents a modified method to correct water-refracted TLS data acquired over mountain channel with complex water-surface slope. Applicability of the modified method was validated using the field data and compared with the existing correction method and non-corrected data. The results showed that the modified method has much smaller error with RMSE value of 3 mm than the existing method (RMSE = 10 mm) and non-corrected data (RMSE = 23 mm). Presented method successfully corrected water-refracted TLS data acquired over sloped channel. This would enable us to quantitatively measure whole units of complex mountain channels, and help us to understand water dynamics better in the area.

  12. Automated Analysis of Barley Organs Using 3D Laser Scanning: An Approach for High Throughput Phenotyping

    PubMed Central

    Paulus, Stefan; Dupuis, Jan; Riedel, Sebastian; Kuhlmann, Heiner

    2014-01-01

    Due to the rise of laser scanning the 3D geometry of plant architecture is easy to acquire. Nevertheless, an automated interpretation and, finally, the segmentation into functional groups are still difficult to achieve. Two barley plants were scanned in a time course, and the organs were separated by applying a histogram-based classification algorithm. The leaf organs were represented by meshing algorithms, while the stem organs were parameterized by a least-squares cylinder approximation. We introduced surface feature histograms with an accuracy of 96% for the separation of the barley organs, leaf and stem. This enables growth monitoring in a time course for barley plants. Its reliability was demonstrated by a comparison with manually fitted parameters with a correlation R2 = 0.99 for the leaf area and R2 = 0.98 for the cumulated stem height. A proof of concept has been given for its applicability for the detection of water stress in barley, where the extension growth of an irrigated and a non-irrigated plant has been monitored. PMID:25029283

  13. Performance Analysis of a Pole and Tree Trunk Detection Method for Mobile Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Lehtomäki, M.; Jaakkola, A.; Hyyppä, J.; Kukko, A.; Kaartinen, H.

    2011-09-01

    Dense point clouds can be collected efficiently from large areas using mobile laser scanning (MLS) technology. Accurate MLS data can be used for detailed 3D modelling of the road surface and objects around it. The 3D models can be utilised, for example, in street planning and maintenance and noise modelling. Utility poles, traffic signs, and lamp posts can be considered an important part of road infrastructure. Poles and trees stand out from the environment and should be included in realistic 3D models. Detection of narrow vertical objects, such as poles and tree trunks, from MLS data was studied. MLS produces huge amounts of data and, therefore, processing methods should be as automatic as possible and for the methods to be practical, the algorithms should run in an acceptable time. The automatic pole detection method tested in this study is based on first finding point clusters that are good candidates for poles and then separating poles and tree trunks from other clusters using features calculated from the clusters and by applying a mask that acts as a model of a pole. The method achieved detection rates of 77.7% and 69.7% in the field tests while 81.0% and 86.5% of the detected targets were correct. Pole-like targets that were surrounded by other objects, such as tree trunks that were inside branches, were the most difficult to detect. Most of the false detections came from wall structures, which could be corrected in further processing.

  14. Assessing modern ground survey methods and airborne laser scanning for digital terrain modelling: A case study from the Lake District, England

    NASA Astrophysics Data System (ADS)

    Gallay, Michal; Lloyd, Christopher D.; McKinley, Jennifer; Barry, Lorraine

    2013-02-01

    This paper compares the applicability of three ground survey methods for modelling terrain: one man electronic tachymetry (TPS), real time kinematic GPS (GPS), and terrestrial laser scanning (TLS). Vertical accuracy of digital terrain models (DTMs) derived from GPS, TLS and airborne laser scanning (ALS) data is assessed. Point elevations acquired by the four methods represent two sections of a mountainous area in Cumbria, England. They were chosen so that the presence of non-terrain features is constrained to the smallest amount. The vertical accuracy of the DTMs was addressed by subtracting each DTM from TPS point elevations. The error was assessed using exploratory measures including statistics, histograms, and normal probability plots. The results showed that the internal measurement accuracy of TPS, GPS, and TLS was below a centimetre. TPS and GPS can be considered equally applicable alternatives for sampling the terrain in areas accessible on foot. The highest DTM vertical accuracy was achieved with GPS data, both on sloped terrain (RMSE 0.16 m) and flat terrain (RMSE 0.02 m). TLS surveying was the most efficient overall but veracity of terrain representation was subject to dense vegetation cover. Therefore, the DTM accuracy was the lowest for the sloped area with dense bracken (RMSE 0.52 m) although it was the second highest on the flat unobscured terrain (RMSE 0.07 m). ALS data represented the sloped terrain more realistically (RMSE 0.23 m) than the TLS. However, due to a systematic bias identified on the flat terrain the DTM accuracy was the lowest (RMSE 0.29 m) which was above the level stated by the data provider. Error distribution models were more closely approximated by normal distribution defined using median and normalized median absolute deviation which supports the use of the robust measures in DEM error modelling and its propagation.

  15. Sealing ability of three root-end filling materials prepared using an erbium: Yttrium aluminium garnet laser and endosonic tip evaluated by confocal laser scanning microscopy

    PubMed Central

    Nanjappa, A Salin; Ponnappa, KC; Nanjamma, KK; Ponappa, MC; Girish, Sabari; Nitin, Anita

    2015-01-01

    Aims: (1) To compare the sealing ability of mineral trioxide aggregate (MTA), Biodentine, and Chitra-calcium phosphate cement (CPC) when used as root-end filling, evaluated under confocal laser scanning microscope using Rhodamine B dye. (2) To evaluate effect of ultrasonic retroprep tip and an erbium:yttrium aluminium garnet (Er:YAG) laser on the integrity of three different root-end filling materials. Materials and Methods: The root canals of 80 extracted teeth were instrumented and obturated with gutta-percha. The apical 3 mm of each tooth was resected and 3 mm root-end preparation was made using ultrasonic tip (n = 30) and Er:YAG laser (n = 30). MTA, Biodentine, and Chitra-CPC were used to restore 10 teeth each. The samples were coated with varnish and after drying, they were immersed in Rhodamine B dye for 24 h. The teeth were then rinsed, sectioned longitudinally, and observed under confocal laser scanning microscope. Statistical Analysis Used: Data were analyzed using one-way analysis of variance (ANOVA) and a post-hoc Tukey's test at P < 0.05 (R software version 3.1.0). Results: Comparison of microleakage showed maximum peak value of 0.45 mm for Biodentine, 0.85 mm for MTA, and 1.05 mm for Chitra-CPC. The amount of dye penetration was found to be lesser in root ends prepared using Er:YAG laser when compared with ultrasonics, the difference was found to be statistically significant (P < 0.05). Conclusions: Root-end cavities prepared with Er:YAG laser and restored with Biodentine showed superior sealing ability compared to those prepared with ultrasonics. PMID:26180420

  16. Ground Deformation Analysis of Blast-Induced Liquefaction at a Simulated Airport Infrastructure Using High Resolution 3D Laser Scanning

    NASA Astrophysics Data System (ADS)

    Minasian, D.; Kayen, R.; Ashford, S.; Kawamata, Y.; Sugano, T.

    2008-12-01

    In October 2007, the Port and Airport Research Institute (PARI) of the Japan Ministry of Land, Infrastructure and Transportation conducted a large-scale blast-induced liquefaction experiment in Ishikari, Hokkaido, Japan. Approximately 24,000 m2 of ground was liquefied using controlled blasting techniques to investigate the performance of airport infrastructure. The USGS and Oregon State University participated in the study and measured topographic changes in ground level using 3D laser scanning techniques (terrestrial lidar), as well as changes in shear wave velocity of the between the pre- and post-liquefied soil. This poster focuses on the lidar results. The overall objective of the PARI experiment is to assess the performance of airport infrastructure subjected to liquefaction. Specifically, the performance of pipelines and large concrete utility raceways located beneath runway pavements is of interest, as well as the performance of pavements and embankments with and without soil improvement techniques. At the site, 5-7 m of loose silty sand was placed as hydraulic fill on natural alluvial sand as an expansion of the Ishikari port facility. On a portion of the liquefied site, three 20 m by 50 m test sections were constructed to investigate the performance of improved ground beneath asphalt runways, concrete runway aprons, and open areas. Pipelines and concrete utility conduits were also buried in each section. The three ground improvement techniques investigated were sand-cement mixing, vertical drains, and colloidal silica injection. The PARI experiment provided an excellent opportunity to conduct terrestrial lidar measurements - a revolutionary tool for accurate characterization of fine-scale changes of topography and identification of subtle deformations. Lidar was used for characterizing post-blast deformations both immediately after the charges were used, and subsequently over time at intervals of 2 days, 4 days, and 5 months after blasting. Settlement

  17. Research of the coastal zone by the airborne laser scanning data (Verbyanaya bay-bar, sea of Azov)

    NASA Astrophysics Data System (ADS)

    Pogorelov, Anatoliy V.; Antonenko, Mihail; Boyko, Evgeniy

    2015-06-01

    In the area Verbyanaya bay-bar (Sea of Azov) in an attempt to create large-scale cartographic base and subsequent thematic mapping of the geographical environment components airborne laser scanning and aerial photography were conducted. Airborne laser scanning data formed the basis of a comprehensive study of the coastal zone components. Methodical research apparatus includes receiving and processing technology of laser reflection points, constructing highprecision digital elevation model and raster surfaces. Mosaic of aerial photography is converted into a format mosaic - a geometrically correct image of the terrain. Set of high-precision digital surface models and thematic raster images obtained for specific dates, allows to analyze the dynamic adjustment of components of the coastal zone (shoreline, beach, shore dam with surge prism).

  18. Integration of e-GPS,RS,GIS, and Laser Scanning Techniques Applied to the Volcanic Slope Slide Monitoring

    NASA Astrophysics Data System (ADS)

    Wu, C.; Chung, Y.; Chen, C.

    2008-12-01

    Taiwan, located at the Western Pacific, bears the threats from both typhoons and earthquakes. The 921 earthquake resulted in the unstable ground so that typhoons or torrential rain could cause serious disasters. Currently, the hazard mitigation is the target of the authorities. However, using the traditional approaches not only wastes a lot of time but also is ineffectively. Thus, the authorities have employed the techniques of e-GPS, GIS, RS (3S) and laser scanning instead of the traditional approaches. This paper introduces the disasters of volcanic slope slide happening in the northern Taiwan and an application of mobile eGPS measurement system for PDA; moreover, the development and application of the techniques of 3S and laser scanning are also presented in this paper.

  19. Standing-wave-excited multiplanar fluorescence in a laser scanning microscope reveals 3D information on red blood cells

    PubMed Central

    Amor, Rumelo; Mahajan, Sumeet; Amos, William Bradshaw; McConnell, Gail

    2014-01-01

    Standing-wave excitation of fluorescence is highly desirable in optical microscopy because it improves the axial resolution. We demonstrate here that multiplanar excitation of fluorescence by a standing wave can be produced in a single-spot laser scanning microscope by placing a plane reflector close to the specimen. We report here a variation in the intensity of fluorescence of successive planes related to the Stokes shift of the dye. We show by the use of dyes specific for the cell membrane how standing-wave excitation can be exploited to generate precise contour maps of the surface membrane of red blood cells, with an axial resolution of ≈90 nm. The method, which requires only the addition of a plane mirror to an existing confocal laser scanning microscope, may well prove useful in studying diseases which involve the red cell membrane, such as malaria. PMID:25483987

  20. Confocal laser scanning microscopy measurement of the morphology of vanadium pentoxide nanorods grown by electron beam irradiation or thermal oxidation

    NASA Astrophysics Data System (ADS)

    Kang, Manil; Hong, Donghyuk; Kim, Taesung; Chu, Minwoo; Kim, Sok Won

    2013-01-01

    In order to observe the morphology of nanostructures at the submicroscale, we use a confocal laser scanning (CLS) microscope built in our laboratory. The theoretical resolution of the hand-made CLS microscope is 150 nm and the performance of the microscope is evaluated by observing a USAF target. Vanadium pentoxide nanorods grown by electron beam irradiation and thermal oxidation methods are used as nanostructures and the morphologies of the nanorods observed by confocal laser scanning microscopy (CLSM) are compared with those obtained by scanning electron microscopy. The magnification and resolution of the CLSM were estimated to be approximately 1500 and 800 nm, respectively. From the results, we confirm that the CLSM can be used to measure nanostructures at the sub-micro-scale without a preconditioning process.

  1. Standing-wave-excited multiplanar fluorescence in a laser scanning microscope reveals 3D information on red blood cells

    NASA Astrophysics Data System (ADS)

    Amor, Rumelo; Mahajan, Sumeet; Amos, William Bradshaw; McConnell, Gail

    2014-12-01

    Standing-wave excitation of fluorescence is highly desirable in optical microscopy because it improves the axial resolution. We demonstrate here that multiplanar excitation of fluorescence by a standing wave can be produced in a single-spot laser scanning microscope by placing a plane reflector close to the specimen. We report here a variation in the intensity of fluorescence of successive planes related to the Stokes shift of the dye. We show by the use of dyes specific for the cell membrane how standing-wave excitation can be exploited to generate precise contour maps of the surface membrane of red blood cells, with an axial resolution of ~90 nm. The method, which requires only the addition of a plane mirror to an existing confocal laser scanning microscope, may well prove useful in studying diseases which involve the red cell membrane, such as malaria.

  2. Application of terrestrial laser scanning for coastal geomorphologic research questions in western Greece

    NASA Astrophysics Data System (ADS)

    Hoffmeister, Dirk; Curdt, Constanze; Tilly, Nora; Ntageretzis, Konstantin; Aasen, Helge; Vött, Andreas; Bareth, Georg

    2013-04-01

    Coasts are areas of permanent change, influenced by gradual changes and sudden impacts. In particular, western Greece is a tectonically active region, due to the nearby plate boundary of the Hellenic Arc. The region has suffered from numerous earthquakes and tsunamis during prehistoric and historic times and is thus characterized by a high seismic and tsunami hazard risk. Additionally, strong winter storms may reach considerable dimensions. In this study, terrestrial laser scanning was applied for (i) annual change detection at seven coastal areas of western Greece for three years (2009-2011) and (ii) accurate parameter detection of large boulders, dislocated by high-energy wave impacts. The Riegl LMS-Z420i laser scanner was used in combination with a precise DGPS system (Topcon HiPer Pro) for all surveys. Each scan position and a further target were recorded for georeferencing and merging of the point clouds. (i) For the annual detection of changes, reference points for the base station of the DGPS system were marked. High-resolution digital elevation models (HRDEM) were generated from each dataset of the different years and are compared to each other, resulting in mass balances. (ii) 3D-models of dislocated boulders were reconstructed and parameters (e.g. volume in combination with density measurements, distance and height above present sea-level) were derived for the solution of wave transport equations, which estimate the minimum wave height or velocity that is necessary for boulder movement. (i) Our results show that annual changes are detectable by multi-temporal terrestrial laser scanning. In general, volumetric changes and affected areas are quantifiable and maps of changes can be established. On exposed beach areas, bigger changes were detectable, where seagrass and sand is eroded and gravel accumulated. In opposite, only minor changes for elevated areas are derived. Dislocated boulders on several sites showed no movement. At coastal areas with a high

  3. Image-based tracking system for vibration measurement of a rotating object using a laser scanning vibrometer

    NASA Astrophysics Data System (ADS)

    Kim, Dongkyu; Khalil, Hossam; Jo, Youngjoon; Park, Kyihwan

    2016-06-01

    An image-based tracking system using laser scanning vibrometer is developed for vibration measurement of a rotating object. The proposed system unlike a conventional one can be used where the position or velocity sensor such as an encoder cannot be attached to an object. An image processing algorithm is introduced to detect a landmark and laser beam based on their colors. Then, through using feedback control system, the laser beam can track a rotating object.

  4. Status and future of laser scanning, synthetic aperture radar and hyperspectral remote sensing data for forest biomass assessment

    NASA Astrophysics Data System (ADS)

    Koch, Barbara

    2010-11-01

    This is a review of the latest developments in different fields of remote sensing for forest biomass mapping. The main fields of research within the last decade have focused on the use of small footprint airborne laser scanning systems, polarimetric synthetic radar interferometry and hyperspectral data. Parallel developments in the field of digital airborne camera systems, digital photogrammetry and very high resolution multispectral data have taken place and have also proven themselves suitable for forest mapping issues. Forest mapping is a wide field and a variety of forest parameters can be mapped or modelled based on remote sensing information alone or combined with field data. The most common information required about a forest is related to its wood production and environmental aspects. In this paper, we will focus on the potential of advanced remote sensing techniques to assess forest biomass. This information is especially required by the REDD (reducing of emission from avoided deforestation and degradation) process. For this reason, new types of remote sensing data such as fullwave laser scanning data, polarimetric radar interferometry (polarimetric systhetic aperture interferometry, PolInSAR) and hyperspectral data are the focus of the research. In recent times, a few state-of-the-art articles in the field of airborne laser scanning for forest applications have been published. The current paper will provide a state-of-the-art review of remote sensing with a particular focus on biomass estimation, including new findings with fullwave airborne laser scanning, hyperspectral and polarimetric synthetic aperture radar interferometry. A synthesis of the actual findings and an outline of future developments will be presented.

  5. Increase of Readability and Accuracy of 3d Models Using Fusion of Close Range Photogrammetry and Laser Scanning

    NASA Astrophysics Data System (ADS)

    Gašparović, M.; Malarić, I.

    2012-07-01

    The development of laser scanning technology has opened a new page in geodesy and enabled an entirely new way of presenting data. Products obtained by the method of laser scanning are used in many sciences, as well as in archaeology. It should be noted that 3D models of archaeological artefacts obtained by laser scanning are fully measurable, written in 1:1 scale and have high accuracy. On the other hand, texture and RGB values of the surface of the object obtained by a laser scanner have lower resolution and poorer radiometric characteristics in relation to the textures captured with a digital camera. Scientific research and the goal of this paper are to increase the accuracy and readability of the 3D model with textures obtained with a digital camera. Laser scanning was performed with triangulation scanner of high accuracy, Vivid 9i (Konica Minolta), while for photogrammetric recording digital camera Nikon D90 with a lens of fixed focal length 20 mm, was used. It is important to stress that a posteriori accuracy score of the global registration of point clouds in the form of the standard deviation was ± 0.136 mm while the average distance was only ± 0.080 mm. Also research has proven that the quality projection texture model increases readability. Recording of archaeological artefacts and making their photorealistic 3D model greatly contributes to archaeology as a science, accelerates processing and reconstruction of the findings. It also allows the presentation of findings to the general public, not just to the experts.

  6. Double-wavelength laser scanning microphotometer (DWLSM) for in-vitro hair shaft and surrounding tissue imaging

    NASA Astrophysics Data System (ADS)

    Fedosov, Ivan V.; Zimnyakov, Dmitry A.; Tuchin, Valery V.; Genina, Elina A.; Altshuler, Gregory B.

    2001-05-01

    The double-wavelength laser scanning microphotometer (DWLSM) with high spatial resolution had been developed for in vitro measuring of hair shaft and follicle absorbance. The instrument allows for determining the absorbance distribution across and along hair shaft and follicle. The instrument is based on standard universal binocular microscope. The construction of the instrument and the data processing reduces the influence of the light scattering on the hair and tissue samples.

  7. Confocal laser scanning microscopy of liesegang rings in odontogenic cysts: analysis of three-dimensional image reconstruction.

    PubMed

    Scivetti, Michele; Lucchese, Alberta; Crincoli, Vito; Pilolli, Giovanni Pietro; Favia, Gianfranco

    2009-01-01

    Liesegang rings are concentric noncellular lamellar structures, occasionally found in inflammatory tissues. They have been confused with various parasites, algas, calcification, and psammoma bodies. The authors examined Liesegang rings from oral inflammatory cysts by both optical and confocal laser scanning microscopy, and perfomed a three-dimensional reconstruction. These investigations indicate that Liesegang rings are composed of multiple birefringent concentric rings, resulting from a progressive deposition of organic substances, with an unclear pathogenesis. PMID:19274580

  8. Photonic crystal fibre enables short-wavelength two-photon laser scanning fluorescence microscopy with fura-2

    NASA Astrophysics Data System (ADS)

    McConnell, Gail; Riis, Erling

    2004-10-01

    We report on a novel and compact reliable laser source capable of short-wavelength two-photon laser scanning fluorescence microscopy based on soliton self-frequency shift effects in photonic crystal fibre. We demonstrate the function of the system by performing two-photon microscopy of smooth muscle cells and cardiac myocytes from the rat pulmonary vein and Chinese hamster ovary cells loaded with the fluorescent calcium indicator fura-2/AM.

  9. In Situ Quantification of Experimental Ice Accretion on Tree Crowns Using Terrestrial Laser Scanning

    PubMed Central

    Nock, Charles A.; Greene, David; Delagrange, Sylvain; Follett, Matt; Fournier, Richard; Messier, Christian

    2013-01-01

    In the eastern hardwood forests of North America ice storms are an important disturbance event. Ice storms strongly influence community dynamics as well as urban infrastructure via catastrophic branch failure; further, the severity and frequency of ice storms are likely to increase with climate change. However, despite a long-standing interest into the effects of freezing rain on forests, the process of ice accretion and thus ice loading on branches remains poorly understood. This is because a number of challenges have prevented in situ measurements of ice on branches, including: 1) accessing and measuring branches in tall canopies, 2) limitations to travel during and immediately after events, and 3) the unpredictability of ice storms. Here, utilizing a novel combination of outdoor experimental icing, manual measurements and terrestrial laser scanning (TLS), we perform the first in situ measurements of ice accretion on branches at differing heights in a tree crown and with increasing duration of exposure. We found that TLS can reproduce both branch and iced branch diameters with high fidelity, but some TLS instruments do not detect ice. Contrary to the expectations of ice accretion models, radial accretion varied sharply within tree crowns. Initially, radial ice accretion was similar throughout the crown, but after 6.5 hours of irrigation (second scanning) radial ice accretion was much greater on upper branches than on lower (∼factor of 3). The slope of the change in radial ice accretion along branches increased with duration of exposure and was significantly greater at the second scanning compared to the first. We conclude that outdoor icing experiments coupled with the use of TLS provide a robust basis for evaluation of models of ice accretion and breakage in tree crowns, facilitating estimation of the limiting breaking stress of branches by accurate measurements of ice loads. PMID:23741409

  10. In situ quantification of experimental ice accretion on tree crowns using terrestrial laser scanning.

    PubMed

    Nock, Charles A; Greene, David; Delagrange, Sylvain; Follett, Matt; Fournier, Richard; Messier, Christian

    2013-01-01

    In the eastern hardwood forests of North America ice storms are an important disturbance event. Ice storms strongly influence community dynamics as well as urban infrastructure via catastrophic branch failure; further, the severity and frequency of ice storms are likely to increase with climate change. However, despite a long-standing interest into the effects of freezing rain on forests, the process of ice accretion and thus ice loading on branches remains poorly understood. This is because a number of challenges have prevented in situ measurements of ice on branches, including: 1) accessing and measuring branches in tall canopies, 2) limitations to travel during and immediately after events, and 3) the unpredictability of ice storms. Here, utilizing a novel combination of outdoor experimental icing, manual measurements and terrestrial laser scanning (TLS), we perform the first in situ measurements of ice accretion on branches at differing heights in a tree crown and with increasing duration of exposure. We found that TLS can reproduce both branch and iced branch diameters with high fidelity, but some TLS instruments do not detect ice. Contrary to the expectations of ice accretion models, radial accretion varied sharply within tree crowns. Initially, radial ice accretion was similar throughout the crown, but after 6.5 hours of irrigation (second scanning) radial ice accretion was much greater on upper branches than on lower (∼factor of 3). The slope of the change in radial ice accretion along branches increased with duration of exposure and was significantly greater at the second scanning compared to the first. We conclude that outdoor icing experiments coupled with the use of TLS provide a robust basis for evaluation of models of ice accretion and breakage in tree crowns, facilitating estimation of the limiting breaking stress of branches by accurate measurements of ice loads. PMID:23741409

  11. Error analysis of motion correction method for laser scanning of moving objects

    NASA Astrophysics Data System (ADS)

    Goel, S.; Lohani, B.

    2014-05-01

    The limitation of conventional laser scanning methods is that the objects being scanned should be static. The need of scanning moving objects has resulted in the development of new methods capable of generating correct 3D geometry of moving objects. Limited literature is available showing development of very few methods capable of catering to the problem of object motion during scanning. All the existing methods utilize their own models or sensors. Any studies on error modelling or analysis of any of the motion correction methods are found to be lacking in literature. In this paper, we develop the error budget and present the analysis of one such `motion correction' method. This method assumes availability of position and orientation information of the moving object which in general can be obtained by installing a POS system on board or by use of some tracking devices. It then uses this information along with laser scanner data to apply correction to laser data, thus resulting in correct geometry despite the object being mobile during scanning. The major application of this method lie in the shipping industry to scan ships either moving or parked in the sea and to scan other objects like hot air balloons or aerostats. It is to be noted that the other methods of "motion correction" explained in literature can not be applied to scan the objects mentioned here making the chosen method quite unique. This paper presents some interesting insights in to the functioning of "motion correction" method as well as a detailed account of the behavior and variation of the error due to different sensor components alone and in combination with each other. The analysis can be used to obtain insights in to optimal utilization of available components for achieving the best results.

  12. Three-dimensional reconstruction of paramecium primaurelia oral apparatus through confocal laser scanning optical microscopy

    NASA Astrophysics Data System (ADS)

    Beltrame, Francesco; Ramoino, Paola; Fato, Marco; Delmonte Corrado, Maria U.; Marcenaro, Giampiero; Crippa Franceschi, Tina

    1992-06-01

    Studies on the complementary mating types of Paramecium primaurelia (Protozoa, Ciliates) have shown that cell lines which differ from each other in mating type expression are characterized by different cell contents, organization, and physiology. Referring to these differences and to the differential rates of food vacuole formation, oral apparatuses of the two mating type cells are assumed to possibly differ from each other in some traits, such as, for instance, in their lengths. In our work, the highly organized oral structures are analyzed by means of a laser scanning confocal optical microscope (CLSM), which provides their 3-D visualization and measurement. The extraction of the 3-D intrinsic information related to the biological objects under investigation can be in turn related to their functional state, according to the classical paradigm of structure to function relationships identification. In our experiments, we acquired different data sets. These are optical slices of the biological sample under investigation, acquired in a confocal situation, through epi-illumination, in reflection, and, for comparison with conventional microscopy, 2-D images acquired via a standard TV camera coupled to the microscope itself. Our CLSM system is equipped with a laser beam at 488 and 514 nm and the data have been acquired with various steps of optical slicing, ranging from .04 to .25 micrometers. The volumes obtained by piling-up the slices are rendered through different techniques, some of them directly implemented on the workstation controlling the CLSM system, some of them on a SUN SPARC station 1, where the original data were transferred via an Ethernet link. In this last instance, original software has been developed for the visualization and animation of the 3-D structures, running under UNIX and X-Window, according to a ray-tracing algorithm.

  13. Fusion of imaging spectroscopy and airborne laser scanning data for characterization of forest ecosystems - A review

    NASA Astrophysics Data System (ADS)

    Torabzadeh, Hossein; Morsdorf, Felix; Schaepman, Michael E.

    2014-11-01

    Forest ecosystems play an important role in the global carbon cycle and it is largely unknown how this role might be altered by transients imposed by global change and deforestation. Remote sensing can provide information on ecosystem state and functioning and, among others, two remote sensing techniques, airborne laser scanning (ALS) and imaging spectroscopy (IS), have been used to characterize forest ecosystems, both independently and combined in fusion approaches. However, the fusion of these datasets should make the best use of the complementarity of both sensors and provide better and more robust vegetation products in forested ecosystems. Similar to other data fusion approaches, satisfying results depend on choosing appropriate fusion levels and methods. In this review paper, we summarize and classify relevant studies that focused on forest characterization using combined ALS and IS data, limited to the last decade. We classified the approaches by fusion level (data or product level) and by choice of methods (physical or empirical methods). Five different categories of products (landcover maps, aboveground biomass, biophysical parameters, gross/net primary productivity and biochemical parameters), have been found as the main aspects of forest ecosystems studied so far. A qualitative accuracy analysis of the products exposed that currently landcover maps are profiting the most from ALS and IS data fusion, while there is room for improvements in respect to the other products, such as biophysical parameters. Only few studies using physical approaches were found, but we expect the use of such approaches will increase with the growing availability of physically based radiative transfer models that can simulate both, ALS and IS data.

  14. On data acquisition of moving objects via kinematic terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Wujanz, D.; Röckelein, S.; Neitzel, F.; Fröhlich, C.

    2013-10-01

    Terrestrial laser scanning (TLS) can be seen as an established method for geodetic data acquisition. Advantageous is its high achievable accuracy as well as its rapid, active and laminar sampling of the object space. However, problems occur if an object, the scanner itself or both are moving which is referred to as kinematic TLS (k-TLS). The cause of this issue is the sequential scanning principle of TLS which causes temporal offsets between measured points and hence describes a distinctive feature to photometric approaches. Due to this temporal shift movements of the scanner or an object lead to geometric falsification during data acquisition. If, however, one can determine current orientation and position of an object or the scanner at any point of time by applying additional sensor technology, geometrically correct and kinematic data acquisition can be derived. The contribution at hand presents a multi sensor system which applies a terrestrial laser scanner for acquisition of an object's surface. In addition three tracking total stations are applied that monitor the object's orientation and position within the coordinate system of the TLS. Influencing factors onto the geometric correction are the accuracy of the applied total stations for determination of six degrees of freedom (6dof) as well as the temporal synchronisation. At first an introduction into the problem domain is exemplified on a simple case. The system is then tested on a 2.5 m long ship model inside a research facility as well as outdoors on a 12 m long vessel. For the sake of assessment the results have been compared to statically acquired scans of the test objects, outside of the water respectively in position of rest, in order to derive reference models.

  15. A reference-free micro defect visualization using pulse laser scanning thermography and image processing

    NASA Astrophysics Data System (ADS)

    Yang, Jinyeol; Choi, Jaemook; Hwang, Soonkyu; An, Yun-Kyu; Sohn, Hoon

    2016-08-01

    As quality control of micro devices and early detection of micro defects in these devices are becoming increasingly important, the demand for a fast and automated online inspection technique to detect micro defects with high spatial resolution is increasing. In this study, a reference-free micro defect visualization algorithm is developed based on laser scanning thermography to detect micro defects in devices instantaneously and automatically with high spatial resolution. A pulse modulated continuous wave laser generates thermal waves in a target device, and the corresponding thermal responses are recorded by an infrared (IR) camera. When the thermal wave encounters a micro defect, the propagation of the thermal wave is blocked at the interface of the micro defect. The blockage of the thermal wave is detected by the proposed reference-free micro defect visualization algorithm. First, an edge detection algorithm is applied to a raw thermal image obtained at a specific time point to extract the thermal discontinuities formed at the boundaries of the defect. The edge images obtained from all time sequences are then assembled into a single accumulated edge image to accentuate defect-induced thermal disturbances in the form of edge features. Finally, the accumulated edge image is automatically processed using a binary imaging algorithm to visualize the micro defect in the target device. The performance of the proposed reference-free micro defect visualization algorithm is examined using two types of specimens, semiconductor chips and ceramic-epoxy composites. The proposed algorithm successfully diagnoses micro defects ranging from 4 μm to 40 μm in width.

  16. Evaluation of Vertical Lacunarity Profiles in Forested Areas Using Airborne Laser Scanning Point Clouds

    NASA Astrophysics Data System (ADS)

    Székely, B.; Kania, A.; Standovár, T.; Heilmeier, H.

    2016-06-01

    The horizontal variation and vertical layering of the vegetation are important properties of the canopy structure determining the habitat; three-dimensional (3D) distribution of objects (shrub layers, understory vegetation, etc.) is related to the environmental factors (e.g., illumination, visibility). It has been shown that gaps in forests, mosaic-like structures are essential to biodiversity; various methods have been introduced to quantify this property. As the distribution of gaps in the vegetation is a multi-scale phenomenon, in order to capture it in its entirety, scale-independent methods are preferred; one of these is the calculation of lacunarity. We used Airborne Laser Scanning point clouds measured over a forest plantation situated in a former floodplain. The flat topographic relief ensured that the tree growth is independent of the topographic effects. The tree pattern in the plantation crops provided various quasi-regular and irregular patterns, as well as various ages of the stands. The point clouds were voxelized and layers of voxels were considered as images for two-dimensional input. These images calculated for a certain vicinity of reference points were taken as images for the computation of lacunarity curves, providing a stack of lacunarity curves for each reference points. These sets of curves have been compared to reveal spatial changes of this property. As the dynamic range of the lacunarity values is very large, the natural logarithms of the values were considered. Logarithms of lacunarity functions show canopy-related variations, we analysed these variations along transects. The spatial variation can be related to forest properties and ecology-specific aspects.

  17. Thermal maturity of Tasmanites microfossils from confocal laser scanning fluorescence microscopy

    USGS Publications Warehouse

    Hackley, Paul C.; Kus, Jolanta

    2015-01-01

    We report here, for the first time, spectral properties of Tasmanites microfossils determined by confocal laser scanning fluorescence microscopy (CLSM, using Ar 458 nm excitation). The Tasmanites occur in a well-characterized natural maturation sequence (Ro 0.48–0.74%) of Devonian shale (n = 3 samples) from the Appalachian Basin. Spectral property λmax shows excellent agreement (r2 = 0.99) with extant spectra from interlaboratory studies which used conventional fluorescence microscopy techniques. This result suggests spectral measurements from CLSM can be used to infer thermal maturity of fluorescent organic materials in geologic samples. Spectra of regions with high fluorescence intensity at fold apices and flanks in individual Tasmanites are blue-shifted relative to less-deformed areas in the same body that have lower fluorescence intensity. This is interpreted to result from decreased quenching moiety concentration at these locations, and indicates caution is needed in the selection of measurement regions in conventional fluorescence microscopy, where it is common practice to select high intensity regions for improved signal intensity and better signal to noise ratios. This study also documents application of CLSM to microstructural characterization of Tasmanites microfossils. Finally, based on an extant empirical relation between conventional λmax values and bitumen reflectance, λmax values from CLSM of Tasmanites microfossils can be used to calculate a bitumen reflectance equivalent value. The results presented herein can be used as a basis to broaden the future application of CLSM in the geological sciences into hydrocarbon prospecting and basin analysis.

  18. Analysis of dolines using multiple methods applied to airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Bauer, Christian

    2015-12-01

    Delineating dolines is not a straightforward process especially in densely vegetated areas. This paper deals quantitatively with the surface karst morphology of a Miocene limestone occurrence in the Styrian Basin, Austria. The study area is an isolated karst mountain with a smooth morphology (former planation surface of Pliocene age), densely vegetated (mixed forest) and with a surface area of 1.3 km2. The study area is located near the city of Wildon and is named "Wildoner Buchkogel". The aim of this study was to test three different approaches in order to automatically delineate dolines. The data basis for this was a high resolution digital terrain model (DTM) derived from airborne laser scanning (ALS) and with a raster resolution of 1 × 1 m. The three different methods for doline boundary delineation are: (a) the "traditional" method based on the outermost closed contour line; (b) boundary extraction based on a drainage correction algorithm (filling up pits), and (c) boundary extraction based on hydrologic modelling (watershed). Extracted features are integrated in a GIS environment and analysed statistically regarding spatial distribution, shape geometry, elongation direction and volume. The three methods lead to different doline boundaries and therefore investigated parameters show significant variations. The applied methods have been compared with respect to their application purpose. Depending on delineation process, between 118 and 189 dolines could be defined. The high density of surface karst features demonstrates that solutional processes are major factors in the landscape development of the Wildoner Buchkogel. Furthermore the correlation to the landscape evolution of the Grazer Bergland is discussed.

  19. Automated identification and geometrical features extraction of individual trees from Mobile Laser Scanning data in Budapest

    NASA Astrophysics Data System (ADS)

    Koma, Zsófia; Székely, Balázs; Folly-Ritvay, Zoltán; Skobrák, Ferenc; Koenig, Kristina; Höfle, Bernhard

    2016-04-01

    Mobile Laser Scanning (MLS) is an evolving operational measurement technique for urban environment providing large amounts of high resolution information about trees, street features, pole-like objects on the street sides or near to motorways. In this study we investigate a robust segmentation method to extract the individual trees automatically in order to build an object-based tree database system. We focused on the large urban parks in Budapest (Margitsziget and Városliget; KARESZ project) which contained large diversity of different kind of tree species. The MLS data contained high density point cloud data with 1-8 cm mean absolute accuracy 80-100 meter distance from streets. The robust segmentation method contained following steps: The ground points are determined first. As a second step cylinders are fitted in vertical slice 1-1.5 meter relative height above ground, which is used to determine the potential location of each single trees trunk and cylinder-like object. Finally, residual values are calculated as deviation of each point from a vertically expanded fitted cylinder; these residual values are used to separate cylinder-like object from individual trees. After successful parameterization, the model parameters and the corresponding residual values of the fitted object are extracted and imported into the tree database. Additionally, geometric features are calculated for each segmented individual tree like crown base, crown width, crown length, diameter of trunk, volume of the individual trees. In case of incompletely scanned trees, the extraction of geometric features is based on fitted circles. The result of the study is a tree database containing detailed information about urban trees, which can be a valuable dataset for ecologist, city planners, planting and mapping purposes. Furthermore, the established database will be the initial point for classification trees into single species. MLS data used in this project had been measured in the framework of

  20. Terrestrial laser scanning for detection of landfill gas: a pilot study

    NASA Astrophysics Data System (ADS)

    Reshetyuk, Yuriy; Mårtensson, Stig-Göran

    2014-04-01

    Methane built up in landfills as a result of breaking down of organic materials can be a renewable energy source if it is taken advantage of. The aim of research presented in this paper is to detect landfill gas (that contains methane) by means of terrestrial laser scanning. The hypothesis is that where no surface leakage has been reported, the landfill gas will expand or migrate. Therefore, it is possible to detect it through repeated scanning of the same area and comparison of Digital Terrain Models (DTMs) generated from the point clouds. Only the most significant movements, i.e. vertical, are of interest in this case. During September-November 2011, a small area at Forsbacka landfill in the vicinity of Gävle was scanned 10 times. Epoch-to-epoch comparisons of the resulting DTMs have shown two significant changes (-27 and +19 mm) in elevation of the surface, and it is not impossible that they are caused by migrating landfill gas. The method tested in this study is deemed to be rigorous and accurate for detecting small-scale swell-shrink behaviour of the ground surface (in our case a landfill surface). However, both data processing and interpretation of the results have been considerably complicated by presence of low vegetation (weeds) on the study site, which was dificult to filter away completely from the data. Based on our pilot study, we recommend that a larger area and a longer period of time are chosen to give basis for more grounded conclusions about presence of landfill gas.

  1. Testing of Land Cover Classification from Multispectral Airborne Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Bakuła, K.; Kupidura, P.; Jełowicki, Ł.

    2016-06-01

    Multispectral Airborne Laser Scanning provides a new opportunity for airborne data collection. It provides high-density topographic surveying and is also a useful tool for land cover mapping. Use of a minimum of three intensity images from a multiwavelength laser scanner and 3D information included in the digital surface model has the potential for land cover/use classification and a discussion about the application of this type of data in land cover/use mapping has recently begun. In the test study, three laser reflectance intensity images (orthogonalized point cloud) acquired in green, near-infrared and short-wave infrared bands, together with a digital surface model, were used in land cover/use classification where six classes were distinguished: water, sand and gravel, concrete and asphalt, low vegetation, trees and buildings. In the tested methods, different approaches for classification were applied: spectral (based only on laser reflectance intensity images), spectral with elevation data as additional input data, and spectro-textural, using morphological granulometry as a method of texture analysis of both types of data: spectral images and the digital surface model. The method of generating the intensity raster was also tested in the experiment. Reference data were created based on visual interpretation of ALS data and traditional optical aerial and satellite images. The results have shown that multispectral ALS data are unlike typical multispectral optical images, and they have a major potential for land cover/use classification. An overall accuracy of classification over 90% was achieved. The fusion of multi-wavelength laser intensity images and elevation data, with the additional use of textural information derived from granulometric analysis of images, helped to improve the accuracy of classification significantly. The method of interpolation for the intensity raster was not very helpful, and using intensity rasters with both first and last return

  2. Supervised identification and reconstruction of near-planar geological surfaces from terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    García-Sellés, D.; Falivene, O.; Arbués, P.; Gratacos, O.; Tavani, S.; Muñoz, J. A.

    2011-10-01

    Terrestrial laser scanning is an effective method for digitally capturing outcrops, enabling them to be visualized, analyzed, and revisited in an office environment without the limitations of fieldwork (such as time constraints, weather conditions, outcrop accessibility, repeatability, and poor resolution of measurements). It is common practice in geological interpretation of digital outcrops to use visual identification and manual digitization of pointsets or polylines in order to characterise geological features using 3D CAD-like modules. Other recent and less generic approaches have focused on automated extraction of geological features by using segmentation methods, mostly based on geometric parameters derived from the point cloud, but also aided by attributes captured from the outcrop (intensity, RGB). This paper presents a workflow for the supervised and automated identification and reconstruction of near-planar geological surfaces that have a three-dimensional exposure in the outcrop (typically bedding, fractures, or faults enhanced by differential erosion). The original point cloud is used without modifications, and thus no decimation, smoothing, intermediate triangulation, or gridding are required. The workflow is based on planar regressions carried out for each point in the point cloud, enabling subsequent filtering and classification to be based on orientation, quality of fit, and relative locations of points. A coarse grid preprocessing strategy is implemented to speed up the search for neighboring points, permitting analysis of multimillion point clouds. The surfaces identified are organized into classes according to their orientations and regression quality parameters. These can then be used as seeds for building outcrop reconstructions or further analyzed to investigate their characteristics (geometry, morphology, spacing, dimensions, intersections, etc.). The workflow is illustrated here using a synthetic example and a natural example from a

  3. Reconstruction of forest geometries from terrestrial laser scanning point clouds for canopy radiative transfer modelling

    NASA Astrophysics Data System (ADS)

    Bremer, Magnus; Schmidtner, Korbinian; Rutzinger, Martin

    2015-04-01

    The architecture of forest canopies is a key parameter for forest ecological issues helping to model the variability of wood biomass and foliage in space and time. In order to understand the nature of subpixel effects of optical space-borne sensors with coarse spatial resolution, hypothetical 3D canopy models are widely used for the simulation of radiative transfer in forests. Thereby, radiation is traced through the atmosphere and canopy geometries until it reaches the optical sensor. For a realistic simulation scene we decompose terrestrial laser scanning point cloud data of leaf-off larch forest plots in the Austrian Alps and reconstruct detailed model ready input data for radiative transfer simulations. The point clouds are pre-classified into primitive classes using Principle Component Analysis (PCA) using scale adapted radius neighbourhoods. Elongated point structures are extracted as tree trunks. The tree trunks are used as seeds for a Dijkstra-growing procedure, in order to obtain single tree segmentation in the interlinked canopies. For the optimized reconstruction of branching architectures as vector models, point cloud skeletonisation is used in combination with an iterative Dijkstra-growing and by applying distance constraints. This allows conducting a hierarchical reconstruction preferring the tree trunk and higher order branches and avoiding over-skeletonization effects. Based on the reconstructed branching architectures, larch needles are modelled based on the hierarchical level of branches and the geometrical openness of the canopy. For radiative transfer simulations, branch architectures are used as mesh geometries representing branches as cylindrical pipes. Needles are either used as meshes or as voxel-turbids. The presented workflow allows an automatic classification and single tree segmentation in interlinked canopies. The iterative Dijkstra-growing using distance constraints generated realistic reconstruction results. As the mesh representation

  4. Understanding the structure of Exmoor's peatland ecosystems using laser-scanning technologies

    NASA Astrophysics Data System (ADS)

    Luscombe, D. J.; Anderson, K.; Wetherelt, A.; Grand-Clement, E.; Le-Feuvre, N.; Smith, D.; Brazier, R. E.

    2012-04-01

    Upland blanket peatlands in the UK are of high conservation value and in an intact state, provide important landscape services, such as carbon sequestration and flood attenuation. The drainage of many such wetlands for agricultural reclamation has resulted in changes to upland blanket mire topography, ecology, hydrological processes and carbon fluxes. There is a need for spatially explicit monitoring approaches at peatland sites in the UK as although there has been a national effort to restore drained peat uplands, baseline and post restoration monitoring of changes to ecosystem structure and function is largely absent. Climate change policy and the emerging carbon markets also necessitate the need for enhanced system understanding to inform carbon targets and understand the impacts of restoration. Exmoor is the focus of this research because many areas of upland peat have, in the past, been extensively drained through government "moorland reclamation" programs. A large restoration project funded by South West Water is currently underway in association with Exmoor National Park, The Environment Agency and Natural England. Exmoor also provides an analogue for other westerly peatlands in the British Isles in terms of its climate, ecology and drainage characteristics. Our approach employed airborne LiDAR data gathered by the Environment Agency Geomatics Group coupled with Terrestrial Laser Scanning (TLS) surveys. LiDAR data were processed to produce digital surface models (DSM) of the peatland surface at a 0.5m resolution. These data were further interrogated to separate vegetation structures and geomorphic features such as man-made drainage channels which have damaged the peatland. Over small extents the LiDAR derived DSM surface was then compared to a TLS derived DSM to examine the ability of these models to describe fine scale vegetation and geomorphic structure, which could then be extrapolated to larger spatial extents. Exploration of the data has shown that

  5. The Effect of Wind on Tree STEM Parameter Estimation Using Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Vaaja, M. T.; Virtanen, J.-P.; Kurkela, M.; Lehtola, V.; Hyyppä, J.; Hyyppä, H.

    2016-06-01

    The 3D measurement technique of terrestrial laser scanning (TLS) in forest inventories has shown great potential for improving the accuracy and efficiency of both individual tree and plot level data collection. However, the effect of wind has been poorly estimated in the error analysis of TLS tree measurements although it causes varying deformations to the trees. In this paper, we evaluated the effect of wind on tree stem parameter estimation at different heights using TLS. The data consists of one measured Scots pine captured from three different scanning directions with two different scanning resolutions, 6.3 mm and 3.1 mm at 10 m. The measurements were conducted under two different wind speeds, approximately 3 m/s and 9 m/s, as recorded by a nearby weather station of the Finnish Meteorological Institute. Our results show that the wind may cause both the underestimation and overestimation of tree diameter when using TLS. The duration of the scanning is found to have an impact for the measured shape of the tree stem under 9 m/s wind conditions. The results also indicate that a 9 m/s wind does not have a significant effect on the stem parameters of the lower part of a tree (<28% of the tree height). However, as the results imply, the wind conditions should be taken into account more comprehensively in analysis of TLS tree measurements, especially if multiple scans from different positions are registered together. In addition, TLS could potentially be applied to indirectly measure wind speed by observing the tree stem movement.

  6. Automatic Stem Mapping by Merging Several Terrestrial Laser Scans at the Feature and Decision Levels

    PubMed Central

    Liang, Xinlian; Hyyppä, Juha

    2013-01-01

    Detailed up-to-date ground reference data have become increasingly important in quantitative forest inventories. Field reference data are conventionally collected at the sample plot level by means of manual measurements, which are both labor-intensive and time-consuming. In addition, the number of attributes collected from the tree stem is limited. More recently, terrestrial laser scanning (TLS), using both single-scan and multi-scan techniques, has proven to be a promising solution for efficient stem mapping at the plot level. In the single-scan method, the laser scanner is placed at the center of the plot, creating only one scan, and all trees are mapped from the single-scan point cloud. Consequently, the occlusion of stems increases as the range of the scanner increases, depending on the forest's attributes. In the conventional multi-scan method, several scans are made simultaneously inside and outside of the plot to collect point clouds representing all trees within the plot, and these scans are accurately co-registered by using artificial reference targets manually placed throughout the plot. The additional difficulty of applying the multi-scan method is due to the point-cloud registration of several scans not being fully automated yet. This paper proposes a multi-single-scan (MSS) method to map the sample plot. The method does not require artificial reference targets placed on the plot or point-level registration. The MSS method is based on the fully automated processing of each scan independently and on the merging of the stem positions automatically detected from multiple scans to accurately map the sample plot. The proposed MSS method was tested on five dense forest plots. The results show that the MSS method significantly improves the stem-detection accuracy compared with the single-scan approach and achieves a mapping accuracy similar to that achieved with the multi-scan method, without the need for the point-level registration. PMID:23353143

  7. Geomorphological Mapping with Terrestrial Laser Scanning and Uav-Based Imaging

    NASA Astrophysics Data System (ADS)

    Tilly, N.; Kelterbaum, D.; Zeese, R.

    2016-06-01

    High-resolution digital elevation models (DEMs) are useful for the detailed mapping of geomorphological features. Nowadays various sensors and platforms are available to collect 3D data. The presented study compares terrestrial laser scanning (TLS) and low-cost unmanned aerial vehicles (UAV)-based imaging in terms of their usability for capturing small-scale surface structures. In October 2014 and June 2015 measurements with both systems were carried out in an episodically water-filled karst depression under pasture farming in the region of Hohenlohe (Southwest Germany). The overall aims were to establish high-resolution DEMs and monitor changes of the relief caused by dissolution and compare the advantages and drawbacks of both systems for such studies. Due to the short time between the campaigns the clear detection of temporal changes was hardly possible. However, the multi-temporal campaigns allowed an extensive investigation of the usability of both sensors under different environmental conditions. In addition to the remote sensing measurements, the coordinates of several positions in the study area were measured with a RTK-DGPS system as independent reference data sets in both campaigns. The TLS- and UAV-derived DEM heights at these positions were validated against the DGPS-derived heights. The accuracy of the TLS-derived values is supported by low mean differences between TLS and DGPS measurements while the UAV-derived models show a weaker performance. In the future years additional simultaneous measurements with both approaches under more similar vegetation conditions are necessary to detect surface movements. Moreover, by investigating the subsurface the interaction of above and below ground processes might be detected.

  8. Using mobile laser scanning data for automated extraction of road markings

    NASA Astrophysics Data System (ADS)

    Guan, Haiyan; Li, Jonathan; Yu, Yongtao; Wang, Cheng; Chapman, Michael; Yang, Bisheng

    2014-01-01

    A mobile laser scanning (MLS) system allows direct collection of accurate 3D point information in unprecedented detail at highway speeds and at less than traditional survey costs, which serves the fast growing demands of transportation-related road surveying including road surface geometry and road environment. As one type of road feature in traffic management systems, road markings on paved roadways have important functions in providing guidance and information to drivers and pedestrians. This paper presents a stepwise procedure to recognize road markings from MLS point clouds. To improve computational efficiency, we first propose a curb-based method for road surface extraction. This method first partitions the raw MLS data into a set of profiles according to vehicle trajectory data, and then extracts small height jumps caused by curbs in the profiles via slope and elevation-difference thresholds. Next, points belonging to the extracted road surface are interpolated into a geo-referenced intensity image using an extended inverse-distance-weighted (IDW) approach. Finally, we dynamically segment the geo-referenced intensity image into road-marking candidates with multiple thresholds that correspond to different ranges determined by point-density appropriate normality. A morphological closing operation with a linear structuring element is finally used to refine the road-marking candidates by removing noise and improving completeness. This road-marking extraction algorithm is comprehensively discussed in the analysis of parameter sensitivity and overall performance. An experimental study performed on a set of road markings with ground-truth shows that the proposed algorithm provides a promising solution to the road-marking extraction from MLS data.

  9. Parametric modeling and optimization of laser scanning parameters during laser assisted machining of Inconel 718

    NASA Astrophysics Data System (ADS)

    Venkatesan, K.; Ramanujam, R.; Kuppan, P.

    2016-04-01

    This paper presents a parametric effect, microstructure, micro-hardness and optimization of laser scanning parameters (LSP) on heating experiments during laser assisted machining of Inconel 718 alloy. The laser source used for experiments is a continuous wave Nd:YAG laser with maximum power of 2 kW. The experimental parameters in the present study are cutting speed in the range of 50-100 m/min, feed rate of 0.05-0.1 mm/rev, laser power of 1.25-1.75 kW and approach angle of 60-90°of laser beam axis to tool. The plan of experiments are based on central composite rotatable design L31 (43) orthogonal array. The surface temperature is measured via on-line measurement using infrared pyrometer. Parametric significance on surface temperature is analysed using response surface methodology (RSM), analysis of variance (ANOVA) and 3D surface graphs. The structural change of the material surface is observed using optical microscope and quantitative measurement of heat affected depth that are analysed by Vicker's hardness test. The results indicate that the laser power and approach angle are the most significant parameters to affect the surface temperature. The optimum ranges of laser power and approach angle was identified as 1.25-1.5 kW and 60-65° using overlaid contour plot. The developed second order regression model is found to be in good agreement with experimental values with R2 values of 0.96 and 0.94 respectively for surface temperature and heat affected depth.

  10. Comparison of high resolution terrestrial laser scanning and terrestrial photogrammetry for modeling applications

    NASA Astrophysics Data System (ADS)

    Özdemir, Samed; Bayrak, Temel

    2016-04-01

    3D documentation of cultural heritage and engineering projects is an important matter. These documentation applications, requires highest possible accuracy and detail to represent the actual surface correctly. Terrestrial photogrammetric method which is employed to produce 3D models to day, now can obtain dense point clouds thanks to advancements in computer technology. Terrestrial laser scanners gained popularity in the last decade because of their high capacity and today they are being widely used in many applications. However every application has its own requirements that depend on the type of application, modeling environment, accuracy and budget limitations. This means, for every application highest accuracy instruments are not always best, considering the facts that mentioned before. In this study, laser scanner and terrestrial photogrammetric methods' spatial and model accuracies investigated under various conditions which include measuring targets at different instrument to object distances then investigating the accuracy of these measurements, modeling an irregular shaped surface to compare two surfaces volume and surface areas, at last comparing dimensions of known geometrical shaped small objects. Also terrestrial laser scanners and terrestrial photogrammetric methods most suitable application conditions investigated in terms of cost, time, mobility and accuracy. Terrestrial laser scanner has the ability to, measure distances under cm accuracy and directly measuring 3D world but there is also some drawbacks like sensitive, bulky and expensive equipment. When it comes to terrestrial photogrammetry, it has above cm accuracy, comparatively fast (considering the image acquisition stage), inexpensive but it can be affected by the coarse geometry, surface texture and the environmental lighting. Key Words: Accuracy, Comparison, Model, Terrestrial Photogrammetry, Terrestrial Laser Scanning,.

  11. A cost-effective laser scanning method for mapping stream channel geometry and roughness

    NASA Astrophysics Data System (ADS)

    Lam, Norris; Nathanson, Marcus; Lundgren, Niclas; Rehnström, Robin; Lyon, Steve

    2015-04-01

    In this pilot project, we combine an Arduino Uno and SICK LMS111 outdoor laser ranging camera to acquire high resolution topographic area scans for a stream channel. The microprocessor and imaging system was installed in a custom gondola and suspended from a wire cable system. To demonstrate the systems capabilities for capturing stream channel topography, a small stream (< 2m wide) in the Krycklan Catchment Study was temporarily diverted and scanned. Area scans along the stream channel resulted in a point spacing of 4mm and a point cloud density of 5600 points/m2 for the 5m by 2m area. A grain size distribution of the streambed material was extracted from the point cloud using a moving window, local maxima search algorithm. The median, 84th and 90th percentiles (common metrics to describe channel roughness) of this distribution were found to be within the range of measured values while the largest modelled element was approximately 35% smaller than its measured counterpart. The laser scanning system captured grain sizes between 30mm and 255mm (coarse gravel/pebbles and boulders based on the Wentworth (1922) scale). This demonstrates that our system was capable of resolving both large-scale geometry (e.g. bed slope and stream channel width) and small-scale channel roughness elements (e.g. coarse gravel/pebbles and boulders) for the study area. We further show that the point cloud resolution is suitable for estimating ecohydraulic parameters such as Manning's n and hydraulic radius. Although more work is needed to fine-tune our system's design, these preliminary results are encouraging, specifically for those with a limited operational budget.

  12. Improving Canopy Vertical Structure Measurements with Dual-Wavelength Laser Scanning

    NASA Astrophysics Data System (ADS)

    Li, Z.; Strahler, A. H.; Schaaf, C.; Jupp, D. L. B.; Howe, G.; Hewawasam, K.; Chakrabarti, S.; Cook, T.; Paynter, I.; Saenz, E. J.; Yang, X.; Yao, T.

    2015-12-01

    Forest canopy structure regulates radiation interception through the canopy, affects the canopy microclimate, and consequently influences the energy, water, and carbon fluxes between soil, vegetation and atmosphere through its interaction with leaf physiological functioning. To observe vertical canopy forest structure in finer and more accurate detail, we retrieved vertical profiles of leaf and woody components separately with a terrestrial laser scanner, the Dual-Wavelength Echidna Lidar (DWEL). DWEL scans of a hardwood site at the Harvard Forest, Petersham, Massachusetts, USA, in early May and in late September in 2014, revealed the spatial heterogeneity of the canopy vertical structure of the two vegetation components: leaves and woody materials. The DWEL collects simultaneous scans of forests with two lasers at different wavelengths, 1064 nm (NIR) and 1548 nm (SWIR). Power returned from leaves is much lower than from woody materials such as trunks and branches at the SWIR wavelength due to the liquid water absorption by leaves, whereas returned power at the NIR wavelength is similar from both leaves and woody materials. This spectral contrast between leaves and woody materials, along with spatial context information. discriminates leaves and woody materials accurately in 3-D space, thus allowing the measurement of separate leaf and woody area profiles. We also captured the change in the canopy vertical structure over the seven years by a comparison between the current measurements by the DWEL in 2014 and past measurements in 2007 at the same site by the DWEL's predecessor, a single-wavelength terrestrial lidar, the Echidna Validation Instrument. The comparison also demonstrates the advantage of dual-wavelength laser scanning by the DWEL for canopy structure measurements.

  13. Aboveground total and green biomass of dryland shrub derived from terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Olsoy, Peter J.; Glenn, Nancy F.; Clark, Patrick E.; Derryberry, DeWayne R.

    2014-02-01

    Sagebrush (Artemisia tridentata), a dominant shrub species in the sagebrush-steppe ecosystem of the western US, is declining from its historical distribution due to feedbacks between climate and land use change, fire, and invasive species. Quantifying aboveground biomass of sagebrush is important for assessing carbon storage and monitoring the presence and distribution of this rapidly changing dryland ecosystem. Models of shrub canopy volume, derived from terrestrial laser scanning (TLS) point clouds, were used to accurately estimate aboveground sagebrush biomass. Ninety-one sagebrush plants were scanned and sampled across three study sites in the Great Basin, USA. Half of the plants were scanned and destructively sampled in the spring (n = 46), while the other half were scanned again in the fall before destructive sampling (n = 45). The latter set of sagebrush plants was scanned during both spring and fall to further test the ability of the TLS to quantify seasonal changes in green biomass. Sagebrush biomass was estimated using both a voxel and a 3-D convex hull approach applied to TLS point cloud data. The 3-D convex hull model estimated total and green biomass more accurately (R2 = 0.92 and R2 = 0.83, respectively) than the voxel-based method (R2 = 0.86 and R2 = 0.73, respectively). Seasonal differences in TLS-predicted green biomass were detected at two of the sites (p < 0.001 and p = 0.029), elucidating the amount of ephemeral leaf loss in the face of summer drought. The methods presented herein are directly transferable to other dryland shrubs, and implementation of the convex hull model with similar sagebrush species is straightforward.

  14. Use of Terrestrial Laser Scanning to Model Fuel Characteristics in Shrub-Steppe

    NASA Astrophysics Data System (ADS)

    Anderson, K.; Glenn, N. F.

    2013-12-01

    Biological invasion, climate change, and other anthropogenic and non-anthropogenic factors are altering ecosystem function of arid shrublands in the western U.S., with notable effects including changes in community composition and increased incidence and severity of wildfires. Wildfire itself contributes to replacement of native flora communities with fire-prone invasives (prominently cheatgrass, Bromus tectorum), a positive feedback loop which threatens long-term degradation of burned areas. Efficient methods of vegetation inventory over large areas are essential to study and manage changes in ecological paradigms, and furthermore to anticipate and control wildfire. However, the application of remote sensing information from aerial or satellite platforms to shrub-steppe ecosystems is limited by spectral signal mixing and coarseness of data relative to low-stature vegetation. Terrestrial laser scanning (TLS) technology provides rapid collection of high-resolution structural information at ranges up to hundreds of meters, offering an opportunity to efficiently record vegetation characteristics in large swaths. We tested the ability of TLS to quantify abundance and biomass of different vegetation stem diameter classes in shrub-steppe plots in southwestern Idaho, with classes selected to emulate timelag fuel classes commonly used in fuel inventories and fire modeling. We used data from destructively-sampled reference quadrats within scans for training and evaluation of TLS-derived estimates. We demonstrate TLS as an effective standalone tool for shrubland vegetation inventory, while future applications of these methods include collecting training data for interpretation of coarser remote sensing information, and providing accurate 3D simulations of fuel beds to spatially explicit wildfire models.

  15. Biochar Erosion in a Temperate Forest Assessed with Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Milenković, Milutin; Bruckman, Viktor; Hollaus, Markus; Pfeifer, Norbert

    2015-04-01

    Biochar amendment in soils is seen as a potential greenhouse gas mitigation strategy. There are a number of examples of successful amendment strategies in agricultural ecosystems, where biochar is mixed with the mineral topsoil by ploughing or similar manipulation techniques. The application in forest ecosystems, however, comes with the limitation that biochar can only be applied directly on the surface. Light-weight biochar particles may be prone to erosion by environmental forces, such as precipitation and wind. We therefore assessed biochar erosion patterns by using Terrestrial Laser Scanning (TLS) in combination with a time-lapse camera on a micro topography scale in a temperate spruce-dominated forest with herbaceous ground vegetation. TLS is a photogrammetric technique that utilizes the laser light detection and ranging (LiDAR) principle to provide high resolution, 3D geometrical information of the object at millimeter scale. A biochar-amended (10 t/ha) plot with the size of ca. 3m x 3m was surveyed with 4 TLS scans taken from each of 4 plot's sides. The acquired scans were co-registered using the professional targets that were installed on the plot's corners. The resulting point cloud was then used as a base for calculating digital terrain model (DTM), to spatially map vegetation heights, vegetation density and roughness. These TLS products were derived by analyzing the geometrical properties of the acquired point cloud. A time-lapse camera was installed during summer 2013, continuously observing the entire plot at 3min intervals. A single, representative, precipitation event in August was selected for a detailed image analysis of biochar particle movement. The analysis showed that areas of notable particle movement correspond to places of flow accumulation simulated from the DTM. This suggests that the very high resolution terrain information can be usefully for planning the biochar amendment on temperate forest ecosystems.

  16. Algorithm for the Automatic Estimation of Agricultural Tree Geometric Parameters Using Airborne Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Hadaś, E.; Borkowski, A.; Estornell, J.

    2016-06-01

    The estimation of dendrometric parameters has become an important issue for the agricultural planning and management. Since the classical field measurements are time consuming and inefficient, Airborne Laser Scanning (ALS) data can be used for this purpose. Point clouds acquired for orchard areas allow to determine orchard structures and geometric parameters of individual trees. In this research we propose an automatic method that allows to determine geometric parameters of individual olive trees using ALS data. The method is based on the α-shape algorithm applied for normalized point clouds. The algorithm returns polygons representing crown shapes. For points located inside each polygon, we select the maximum height and the minimum height and then we estimate the tree height and the crown base height. We use the first two components of the Principal Component Analysis (PCA) as the estimators for crown diameters. The α-shape algorithm requires to define the radius parameter R. In this study we investigated how sensitive are the results to the radius size, by comparing the results obtained with various settings of the R with reference values of estimated parameters from field measurements. Our study area was the olive orchard located in the Castellon Province, Spain. We used a set of ALS data with an average density of 4 points m-2. We noticed, that there was a narrow range of the R parameter, from 0.48 m to 0.80 m, for which all trees were detected and for which we obtained a high correlation coefficient (> 0.9) between estimated and measured values. We compared our estimates with field measurements. The RMSE of differences was 0.8 m for the tree height, 0.5 m for the crown base height, 0.6 m and 0.4 m for the longest and shorter crown diameter, respectively. The accuracy obtained with the method is thus sufficient for agricultural applications.

  17. Morphological Changes Along a Dike Landside Slope Sampled by 4d High Resolution Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Herrero-Huertaa, Mónica; Lindenbergh, Roderik; Ponsioen, Luc; van Damme, Myron

    2016-06-01

    Emergence of light detection and ranging (LiDAR) technology provides new tools for geomorphologic studies improving spatial and temporal resolution of data sampling hydrogeological instability phenomena. Specifically, terrestrial laser scanning (TLS) collects high resolution 3D point clouds allowing more accurate monitoring of erosion rates and processes, and thus, quantify the geomorphologic change on vertical landforms like dike landside slopes. Even so, TLS captures observations rapidly and automatically but unselectively. In this research, we demonstrate the potential of TLS for morphological change detection, profile creation and time series analysis in an emergency simulation for characterizing and monitoring slope movements in a dike. The experiment was performed near Schellebelle (Belgium) in November 2015, using a Leica Scan Station C10. Wave overtopping and overflow over a dike were simulated whereby the loading conditions were incrementally increased and 14 successful scans were performed. The aim of the present study is to analyse short-term morphological dynamic processes and the spatial distribution of erosion and deposition areas along a dike landside slope. As a result, we are able to quantify the eroded material coming from the impact on the terrain induced by wave overtopping which caused the dike failure in a few minutes in normal storm scenarios (Q = 25 l/s/m) as 1.24 m3. As this shows that the amount of erosion is measurable using close range techniques; the amount and rate of erosion could be monitored to predict dike collapse in emergency situation. The results confirm the feasibility of the proposed methodology, providing scalability to a comprehensive analysis over a large extension of a dike (tens of meters).

  18. Comparison of airborne laser scanning methods for estimating forest structure indicators based on Lorenz curves

    NASA Astrophysics Data System (ADS)

    Valbuena, Rubén; Vauhkonen, Jari; Packalen, Petteri; Pitkänen, Juho; Maltamo, Matti

    2014-09-01

    The purpose of this study was to compare a number of state-of-the-art methods in airborne laser scanning (ALS) remote sensing with regards to their capacity to describe tree size inequality and other indicators related to forest structure. The indicators chosen were based on the analysis of the Lorenz curve: Gini coefficient (GC), Lorenz asymmetry (LA), the proportions of basal area (BALM) and stem density (NSLM) stocked above the mean quadratic diameter. Each method belonged to one of these estimation strategies: (A) estimating indicators directly; (B) estimating the whole Lorenz curve; or (C) estimating a complete tree list. Across these strategies, the most popular statistical methods for area-based approach (ABA) were used: regression, random forest (RF), and nearest neighbour imputation. The latter included distance metrics based on either RF (NN-RF) or most similar neighbour (MSN). In the case of tree list estimation, methods based on individual tree detection (ITD) and semi-ITD, both combined with MSN imputation, were also studied. The most accurate method was direct estimation by best subset regression, which obtained the lowest cross-validated coefficients of variation of their root mean squared error CV(RMSE) for most indicators: GC (16.80%), LA (8.76%), BALM (8.80%) and NSLM (14.60%). Similar figures [CV(RMSE) 16.09%, 10.49%, 10.93% and 14.07%, respectively] were obtained by MSN imputation of tree lists by ABA, a method that also showed a number of additional advantages, such as better distributing the residual variance along the predictive range. In light of our results, ITD approaches may be clearly inferior to ABA with regards to describing the structural properties related to tree size inequality in forested areas.

  19. Laser scanning cytometry and tissue microarray analysis of salinity effects on killifish chloride cells.

    PubMed

    Lima, Raquel N; Kültz, Dietmar

    2004-04-01

    The effects of salinity on chloride cells (CC) and Na(+)/K(+)-ATPase content in gill epithelium of euryhaline killifish Fundulus heteroclitus were analyzed using laser scanning cytometry (LSC) and tissue microarrays (TMAs). Salinity acclimations consisted of acute transfer from freshwater (FW) to 1x seawater (SW) and gradual transfer from FW to 2.4x SW. Suspensions of dissociated gill epithelial cells were stained with DASPMI and evaluated using LSC. CC number and volume are proportional to external salinity, being lower in FW (0.5+/-0.2 x 10(5) and 405+/-32 micro m(3), respectively) and higher after 5 weeks in 2.4x SW (3.7+/-0.9 x 10(5) and 2697+/-146 micro m(3), respectively). TMAs were constructed from fixed gill tissues and developed using antibody for Na(+)/K(+)-ATPase to visualize CCs in situ and compare their characteristics with isolated CCs. Na(+)/K(+)-ATPase content per CC increases transiently (from 2.2+/-0.5 x 10(6) to 4.8+/-1.1 x 10(6) relative fluorescence units, RFU) after 1 week of acute acclimation to 1x SW but returns to baseline values (2.4+/-0.5 x 10(6) RFU) within 5 weeks. In contrast, gradual acclimation to 2.4x SW permanently increases Na(+)/K(+)-ATPase content per CC (from 2.0+/-0.8 x 10(6) to 6.7+/-2.7 x 10(6) RFU after 5 weeks). CC size in situ did not correlate well to salinity because of basolateral membrane infoldings. Taken together, these data suggest that euryhaline fishes are capable of sensing environmental salinity to utilize transient short-term and permanent long-term adaptations for coping with salinity changes. These results also demonstrate the power of LSC and TMA for comparative biology. PMID:15073205

  20. Detection of Aspens Using High Resolution Aerial Laser Scanning Data and Digital Aerial Images

    PubMed Central

    Säynäjoki, Raita; Packalén, Petteri; Maltamo, Matti; Vehmas, Mikko; Eerikäinen, Kalle

    2008-01-01

    The aim was to use high resolution Aerial Laser Scanning (ALS) data and aerial images to detect European aspen (Populus tremula L.) from among other deciduous trees. The field data consisted of 14 sample plots of 30 m × 30 m size located in the Koli National Park in the North Karelia, Eastern Finland. A Canopy Height Model (CHM) was interpolated from the ALS data with a pulse density of 3.86/m2, low-pass filtered using Height-Based Filtering (HBF) and binarized to create the mask needed to separate the ground pixels from the canopy pixels within individual areas. Watershed segmentation was applied to the low-pass filtered CHM in order to create preliminary canopy segments, from which the non-canopy elements were extracted to obtain the final canopy segmentation, i.e. the ground mask was analysed against the canopy mask. A manual classification of aerial images was employed to separate the canopy segments of deciduous trees from those of coniferous trees. Finally, linear discriminant analysis was applied to the correctly classified canopy segments of deciduous trees to classify them into segments belonging to aspen and those belonging to other deciduous trees. The independent variables used in the classification were obtained from the first pulse ALS point data. The accuracy of discrimination between aspen and other deciduous trees was 78.6%. The independent variables in the classification function were the proportion of vegetation hits, the standard deviation of in pulse heights, accumulated intensity at the 90th percentile and the proportion of laser points reflected at the 60th height percentile. The accuracy of classification corresponded to the validation results of earlier ALS-based studies on the classification of individual deciduous trees to tree species.

  1. Modeling river bed morphology, roughness, and surface sedimentology using high resolution terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Brasington, J.; Vericat, D.; Rychkov, I.

    2012-11-01

    Recent advances in technology have revolutionized the acquisition of topographic data, offering new perspectives on the structure and morphology of the Earth's surface. These developments have had a profound impact on the practice of river science, creating a step change in the dimensionality, resolution, and precision of fluvial terrain models. The emergence of "hyperscale" survey methods, including structure from motion photogrammetry and terrestrial laser scanning (TLS), now presents the opportunity to acquire 3-D point cloud data that capture grain-scale detail over reach-scale extents. Translating these data into geomorphologically relevant products is, however, not straightforward. Unlike traditional survey methods, TLS acquires observations rapidly and automatically, but unselectively. This results in considerable "noise" associated with backscatter from vegetation and other artifacts. Moreover, the large data volumes are difficult to visualize; require very high capacity storage; and are not incorporated readily into GIS and simulation models. In this paper we analyze the geomorphological integrity of multiscale terrain models rendered from a TLS survey of the braided River Feshie, Scotland. These raster terrain models are generated using a new, computationally efficient geospatial toolkit: the topographic point cloud analysis toolkit (ToPCAT). This performs an intelligent decimation of point cloud data into a set of 2.5-D terrain models that retain information on the high-frequency subgrid topography, as the moments of the locally detrended elevation distribution. The results quantify the degree of terrain generalization inherent in conventional fluvial DEMs and illustrate how subgrid topographic statistics can be used to map the spatial pattern of particle size, grain roughness, and sedimentary facies at the reach scale.

  2. Application of laser scanning microscopy for the analysis of oral biofilm dissolution by different endodontic irrigants

    PubMed Central

    del Carpio-Perochena, Aldo; Bramante, Clovis Monteiro; Hungaro Duarte, Marco Antonio; de Andrade, Flaviana Bombarda; Cavenago, Bruno Cavalini; Villas-Bôas, Marcelo Haas; Ordinola-Zapata, Ronald; Amoroso-Silva, Pablo

    2014-01-01

    Background: Multi-specie biofilms are highly resistant to antimicrobials due to cellular interactions found in them. The purpose of this study was to evaluate, by confocal laser scanning microscopy, the biofilm dissolution effectiveness of different irrigant solutions on biofilms developed on infected dentin in situ. Materials and Methods: A total of 120 bovine dentin specimens infected intraorally (30/group) were treated by the following solutions: 2% of chlorhexidine digluconate, 1%, 2.5% and 5.25% of sodium hypochlorite (NaOCl). The solutions were utilized for 5, 15 and 30 min with 2 experimental volumes 500 μL and 1 mL. All the samples were stained using an acridine orange and the biofilm thickness before (control group) and after the experiments were evaluated, utilizing a confocal microscope at ×40. The Mann-Whitney U and the nom-parametric Kruskal-Wallis Dunns tests were utilized to determine the influence of the volume and to perform the comparisons among the groups respectively. The significance level was set at P < 0.05. Results: Statistical differences were not found among the control and the 2% chlorhexidine digluconate groups at any experimental period (P > 0.05). The biofilm dissolution treated with 1% NaOCl was directly proportional to the exposure time (P < 0.05). The higher values of biofilm dissolution were found in 2.5% and 5.25% NaOCl groups (P > 0.05). Conclusion: The higher exposure times and concentrations of NaOCl were not sufficient to dissolve 100% of the biofilm. However, all NaOCl solutions were more effective than 2% chlorhexidine digluconate to dissolve organic matter. PMID:25225556

  3. Derivation of tree stem structural parameters from static terrestrial laser scanning data

    NASA Astrophysics Data System (ADS)

    Tian, Wei; Lin, Yi; Liu, Yajing; Niu, Zheng

    2014-11-01

    Accurate tree-level characteristic information is increasingly demanded for forest management and environment protection. The cutting-edge remote sensing technique of terrestrial laser scanning (TLS) shows the potential of filling this gap. This study focuses on exploring the methods for deriving various tree stem structural parameters, such as stem position, diameter at breast height (DBH), the degree of stem shrinkage, and the elevation angle and azimuth angle of stem inclination. The data for test was collected with a Leica HDS6100 TLS system in Seurasaari, Southern Finland in September 2010. In the field, the reference positions and DBHs of 100 trees were measured manually. The isolation of individual trees is based on interactive segmentation of point clouds. The estimation of stem position and DBH is based on the schematic of layering and then least-square-based circle fitting in each layer. The slope of robust fit line between the height of each layer and DBH is used to characterize the stem shrinkage. The elevation angle of stem inclination is described by the angle between the ground plane and the fitted stem axis. The angle between the north direction and the fitted stem axis gives the azimuth angle of stem inclination. The estimation of the DBHs performed with R square (R2) of 0.93 and root mean square error (RMSE) of 0.038m.The average angle corresponding to stem shrinkage is -1.86°. The elevation angles of stem inclinations are ranged from 31° to 88.3°. The results have basically validated TLS for deriving multiple structural parameters of stem, which help better grasp tree specialties.

  4. Estimating single-tree branch biomass of Norway spruce by airborne laser scanning

    NASA Astrophysics Data System (ADS)

    Hauglin, Marius; Dibdiakova, Janka; Gobakken, Terje; Næsset, Erik

    2013-05-01

    The use of forest biomass for bioenergy purposes, directly or through refinement processes, has increased in the last decade. One example of such use is the utilization of logging residues. Branch biomass constitutes typically a considerable part of the logging residues, and should be quantified and included in future forest inventories. Airborne laser scanning (ALS) is widely used when collecting data for forest inventories, and even methods to derive information at the single-tree level has been described. Procedures for estimation of single-tree branch biomass of Norway spruce using features derived from ALS data are proposed in the present study. As field reference data the dry weight branch biomass of 50 trees were obtained through destructive sampling. Variables were further derived from the ALS echoes from each tree, including crown volume calculated from an interpolated crown surface constructed with a radial basis function. Spatial information derived from the pulse vectors were also incorporated when calculating the crown volume. Regression models with branch biomass as response variable were fit to the data, and the prediction accuracy assessed through a cross-validation procedure. Random forest regression models were compared to stepwise and simple linear least squares models. In the present study branch biomass was estimated with a higher accuracy by the best ALS-based models than by existing allometric biomass equations based on field measurements. An improved prediction accuracy was observed when incorporating information from the laser pulse vectors into the calculation of the crown volume variable, and a linear model with the crown volume as a single predictor gave the best overall results with a root mean square error of 35% in the validation.

  5. Toward Automated Analysis of Biofilm Architecture: Bias Caused by Extraneous Confocal Laser Scanning Microscopy Images▿

    PubMed Central

    Merod, Robin T.; Warren, Jennifer E.; McCaslin, Hope; Wuertz, Stefan

    2007-01-01

    An increasing number of studies utilize confocal laser scanning microscopy (CLSM) for in situ visualization of biofilms and rely on the use of image analysis programs to extract quantitative descriptors of architecture. Recently, designed programs have begun incorporating procedures to automatically determine threshold values for three-dimensional CLSM image stacks. We have found that the automated threshold calculation is biased when a stack contains images lacking pixels of biological significance. Consequently, we have created the novel program Auto PHLIP-ML to resolve this bias by iteratively excluding extraneous images based on their area coverage of biomass. A procedure was developed to identify the optimal percent area coverage value used for extraneous image removal (PACVEIR). The optimal PACVEIR was defined to occur when the standard deviation of mean thickness, determined from replicate image stacks, was at a maximum, because it more accurately reflected inherent structural variation. Ten monoculture biofilms of either Ralstonia eutropha JMP228n::gfp or Acinetobacter sp. strain BD413 were tested to verify the routine. All biofilms exhibited an optimal PACVEIR between 0 and 1%. Prior to the exclusion of extraneous images, JMP228n::gfp appeared to develop more homogeneous biofilms than BD413. However, after the removal of extraneous images, JMP228n::gfp biofilms were found to form more heterogeneous biofilms. Similarly, JMP228n::gfp biofilms grown on glass surfaces vis-à-vis polyethylene membranes produced significantly different architectures after extraneous images had been removed but not when such images were included in threshold calculations. This study shows that the failure to remove extraneous images skewed a seemingly objective analysis of biofilm architecture and significantly altered statistically derived conclusions. PMID:17545329

  6. Quantification of Overnight Movement of Birch (Betula pendula) Branches and Foliage with Short Interval Terrestrial Laser Scanning.

    PubMed

    Puttonen, Eetu; Briese, Christian; Mandlburger, Gottfried; Wieser, Martin; Pfennigbauer, Martin; Zlinszky, András; Pfeifer, Norbert

    2016-01-01

    The goal of the study was to determine circadian movements of silver birch (Petula Bendula) branches and foliage detected with terrestrial laser scanning (TLS). The study consisted of two geographically separate experiments conducted in Finland and in Austria. Both experiments were carried out at the same time of the year and under similar outdoor conditions. Experiments consisted of 14 (Finland) and 77 (Austria) individual laser scans taken between sunset and sunrise. The resulting point clouds were used in creating a time series of branch movements. In the Finnish data, the vertical movement of the whole tree crown was monitored due to low volumetric point density. In the Austrian data, movements of manually selected representative points on branches were monitored. The movements were monitored from dusk until morning hours in order to avoid daytime wind effects. The results indicated that height deciles of the Finnish birch crown had vertical movements between -10.0 and 5.0 cm compared to the situation at sunset. In the Austrian data, the maximum detected representative point movement was 10.0 cm. The temporal development of the movements followed a highly similar pattern in both experiments, with the maximum movements occurring about an hour and a half before (Austria) or around (Finland) sunrise. The results demonstrate the potential of terrestrial laser scanning measurements in support of chronobiology. PMID:26973668

  7. Mobile connected dermatoscope and confocal laser scanning microscope: a useful combination applied in facial simple sensitive skin.

    PubMed

    Zha, W F; Song, W M; Ai, J J; Xu, A E

    2012-08-01

    Little is known as the effects of mobile connected dermatoscope services on diagnostic accuracy for sensitive skin. Confocal laser scanning microscope (CLSM) can non-invasively measure the thickness of epidermis. Combination of the two devices to observe sensitive skin may receive unexpected effects. To evaluate the application effect on sensitive skin with the combination of Handyscope and confocal laser scanning microscope. Twenty simple sensitive-skinned patients and 20 volunteers participated in the study. Cheek, typically, dermoscopic images were obtained from patients, and the changes in the skin texture were observed. Their epidermis thicknesses as well as the volunteers' were measured so that the thicknesses of the two groups were compared. Dermoscopic pictures of the skin texture obviously showed that dilated capillaries looked like earthworms with pigmented patches more or less floating above, and skin roughness as well as deepened dermatoglyph were also conspicuously present in some patients. The mean epidermal thickness of the patients was 79.01 μm and the volunteers' was 85.78 μm. The difference between the two groups reached 6.77 μm. There was a statistical significance (P = 0.001). Mobile connected dermatoscope and confocal laser scanning microscope might be the choice for simple sensitive skin investigation. PMID:22515509

  8. Quantification of Overnight Movement of Birch (Betula pendula) Branches and Foliage with Short Interval Terrestrial Laser Scanning

    PubMed Central

    Puttonen, Eetu; Briese, Christian; Mandlburger, Gottfried; Wieser, Martin; Pfennigbauer, Martin; Zlinszky, András; Pfeifer, Norbert

    2016-01-01

    The goal of the study was to determine circadian movements of silver birch (Petula Bendula) branches and foliage detected with terrestrial laser scanning (TLS). The study consisted of two geographically separate experiments conducted in Finland and in Austria. Both experiments were carried out at the same time of the year and under similar outdoor conditions. Experiments consisted of 14 (Finland) and 77 (Austria) individual laser scans taken between sunset and sunrise. The resulting point clouds were used in creating a time series of branch movements. In the Finnish data, the vertical movement of the whole tree crown was monitored due to low volumetric point density. In the Austrian data, movements of manually selected representative points on branches were monitored. The movements were monitored from dusk until morning hours in order to avoid daytime wind effects. The results indicated that height deciles of the Finnish birch crown had vertical movements between -10.0 and 5.0 cm compared to the situation at sunset. In the Austrian data, the maximum detected representative point movement was 10.0 cm. The temporal development of the movements followed a highly similar pattern in both experiments, with the maximum movements occurring about an hour and a half before (Austria) or around (Finland) sunrise. The results demonstrate the potential of terrestrial laser scanning measurements in support of chronobiology. PMID:26973668

  9. Evaluating point cloud accuracy of static three-dimensional laser scanning based on point cloud error ellipsoid model

    NASA Astrophysics Data System (ADS)

    Chen, Xijiang; Hua, Xianghong; Zhang, Guang; Wu, Hao; Xuan, Wei; Li, Moxiao

    2015-01-01

    Evaluation of static three-dimensional (3-D) laser scanning point cloud accuracy has become a topical research issue. Point cloud accuracy is typically estimated by comparing terrestrial laser scanning data related to a finite number of check point coordinates against those obtained by an independent source of higher accuracy. These methods can only estimate the point accuracy but not the point cloud accuracy, which is influenced by the positional error and sampling interval. It is proposed that the point cloud error ellipsoid is favorable for inspecting the point cloud accuracy, which is determined by the individual point error ellipsoid volume. The kernel of this method is the computation of the point cloud error ellipsoid volume and the determination of the functional relationship between the error ellipsoid and accuracy. The proposed point cloud accuracy evaluation method is particularly suited for small sampling intervals when there exists an intersection of two error ellipsoids, and is suited not only for planar but also for nonplanar target surfaces. The performance of the proposed method (PM) is verified using both planar and nonplanar board point clouds. The results demonstrate that the proposed evaluation method significantly outperforms the existing methods when the target surface is nonplanar or there exists an intersection of two error ellipsoids. The PM therefore has the potential for improving the reliability of point cloud digital elevation models and static 3-D laser scanning-based deformation monitoring.

  10. Detection of morphological changes in cliff face surrounding a waterfall using terrestrial laser scanning and unmanned aerial system

    NASA Astrophysics Data System (ADS)

    Hayakawa, Yuichi S.; Obanawa, Hiroyuki

    2015-04-01

    Waterfall or bedrock knickpoint appears as an erosional front in bedrock rivers forming deep v-shaped valley downstream. Following the rapid fluvial erosion of waterfall, rockfalls and gravita-tional collapses often occur in surrounding steep cliffs. Although morphological changes of such steep cliffs are sometimes visually observed, quantitative and precise measurements of their spatio-temporal distribution have been limited due to the difficulties in direct access to such cliffs if with classical measurement methods. However, for the clarification of geomorphological processes oc-curring in the cliffs, multi-temporal mapping of the cliff face at a high resolution is necessary. Re-mote sensing approaches are therefore suitable for the topographic measurements and detection of changes in such inaccessible cliffs. To achieve accurate topographic mapping of cliffs around a wa-terfall, here we perform multi-temporal terrestrial laser scanning (TLS), as well as structure-from-motion multi-view stereo (SfM-MVS) photogrammetry based on unmanned aerial system (UAS). The study site is Kegon Falls in central Japan, having a vertical drop of surface water from top of its overhanging cliff, as well as groundwater outflows from its lower portions. The bedrock is composed of alternate layers of andesite lava and conglomerates. Minor rockfalls in the cliffs are often ob-served by local people. The latest major rockfall occurred in 1986, causing ca. 8-m upstream propa-gation of the waterfall lip. This provides a good opportunity to examine the changes in the surround-ing cliffs following the waterfall recession. Multi-time point clouds were obtained by TLS measure-ment over years, and the three-dimensional changes of the rock surface were detected, uncovering the locus of small rockfalls and gully developments. Erosion seems particularly frequent in relatively weak the conglomerates layer, whereas small rockfalls seems to have occurred in the andesite layers. Also, shadows in the

  11. Spiral ganglion neuron quantification in the guinea pig cochlea using Confocal Laser Scanning Microscopy compared to embedding methods.

    PubMed

    Wrzeszcz, Antonina; Reuter, Günter; Nolte, Ingo; Lenarz, Thomas; Scheper, Verena

    2013-12-01

    Neuron counting in the cochlea is a crucial but time-consuming operation for which various methods have been developed. To improve simplicity and efficiency, we tested an imaging method of the cochlea, and based on Confocal Laser Scanning Microscopy (CLSM), we visualised Rosenthal's Canal and quantified the spiral ganglion neurons (SGN) within. Cochleae of 8 normal hearing guinea pigs and one implanted with a silicone filament were fixed in paraformaldehyde (PFA), decalcified, dehydrated and cleared in Spalteholz solution. Using the tissue's autofluorescence, CLSM was performed at 100 fold magnification generating z-series stacks of about 20 slices of the modiolus. In 5 midmodiolar slices per cochlea the perimeters of the Rosenthal's Canal were surveyed, representative neuron diameters were measured and the neurons first counted manually and then software-assisted. For comparison, 8 normal hearing guinea pig cochleae were embedded in paraffin and examined similarly. The CLSM method has the advantage that the cochleae remain intact as an organ and keep their geometrical structure. Z-stack creation is nearly fully-automatic and frequently repeatable with various objectives and step sizes and without visible bleaching. The tissue shows minimal or no shrinking artefacts and damage typical of embedding and sectioning. As a result, the cells in the cleared cochleae reach an average diameter of 21 μm and a density of about 18 cells/10,000 μm(2) with no significant difference between the manual and the automatical counts. Subsequently we compared the CLSM data with those generated using the established method of paraffin slides, where the SGN reached a mean density of 9.5 cells/10,000 μm(2) and a mean soma diameter of 13.6 μm. We were able to prove that the semi-automatic CLSM method is a simple and effective technique for auditory neuron count. It provides a high grade of tissue preservation and the automatic stack-generation as well as the counter software reduces

  12. Expression of keratin 14 in the basal cells of the lingual epithelium of mice during the morphogenesis of filiform papillae: visualization by fluorescent immunostaining and confocal laser-scanning microscopy in the transmission mode.

    PubMed

    Iwasaki, Shin-Ichi; Aoyagi, Hidekazu

    2007-07-01

    We examined the expression of keratin 14 (K14) on the lingual epithelium by immunofluorescent staining while monitoring morphological changes in the filiform papillae of mice by confocal laser-scanning microscopy in the transmission mode of the same sections to define both the histology and the morphology of cells. It is difficult to visualize histological details of the fetal lingual epithelium of the mouse on semi-ultrathin sections by light microscopy after immunohistochemical staining because the histological structures in such sections cannot be distinguished by standard counterstaining. To solve this problem and to visualize the immunoreactivity specific for K14, we analyzed the results of immunofluorescent staining of semi-ultrathin sections in combination with an examination of the corresponding images by laser-scanning microscopy in the transmission mode after staining of specimens with toluidine blue. No immunoreactivity specific for K14 was detected on the lingual epithelium of fetuses on embryonic day 15 (E15), but immunoreactivity was distinct at all postnatal stages from postnatal day 0 (P0) to P21. PMID:17660983

  13. Use of terrestrial laser scanning for the documentation of quaternary caves

    NASA Astrophysics Data System (ADS)

    Tyszkowski, Sebastian; Kramkowski, Mateusz; Wiśniewska, Daria; Urban, Jan

    2016-04-01

    Due to the nature of their occurrence and genesis, caves in the Polish Lowlands represent a peculiarity of geological heritage, unique on the European scale. They are developed in Quaternary deposits, mostly at the contact of slabs or irregular bodies of cemented glacial or glaciofluvial deposits: conglomerates and sandstones, with unconsolidated deposits, mostly sands, gravels and clays. So far, 20 such caves have been recorded in Polish Lowlands. Most caves are only several meters long, the largest one is over 60 m long. Regardless of their origins, the character of host rocks is the reason that processes leading to their formation are simultaneously the destroying processes. Thus, the studied caves, as well as other caves of this region, are unstable, gradually evolving objects. The changes taking place in them are continuous and intense enough, therefore the documentation of their shape with the greatest possible accuracy and resolution becomes crucial. Such possibility can provide the technique of laser scanning. In 2014 three caves, including one recently discovered, were scanned using the TLS. Measurements of caves and their surroundings were conducted in May and July 2014 with a scanner RIEGL VZ-4000. Point clouds from several scanner positions were combined using the module Multi Station Adjustment in the RiSCAN software. This module allows to connect point clouds from successive positions without any objects of reference. After the merger of point clouds from individual positions and their filtration, a collection of several million points was obtained. The number of points projected on the wall was over 20 000 per m2. The using of TLS enabled to present the morphometric features impossible to obtain using traditional methods. High density of the point clouds allows registering even small details on the cave walls, as well as monitoring leaching, falling, grinding and flaking processes taking place in them. Thus, the most important advantage of the TLS is

  14. Tension zones of deep-seated rockslides revealed by thermal anomalies and airborne laser scan data

    NASA Astrophysics Data System (ADS)

    Baroň, Ivo; Bečkovský, David; Gajdošík, Juraj; Opálka, Filip; Plan, Lukas; Winkler, Gerhard

    2015-04-01

    Open cracks, tension fractures and crevice caves are important diagnostic features of gravitationally deformed slopes. When the cracks on the upper part of the slope open to the ground surface, they transfer relatively warm and buoyant air from the underground in cold seasons and thus could be detected by the infrared thermography (IRT) as warmer anomalies. Here we present two IRT surveys of deep-seated rockslides in Austria and the Czech Republic. We used thermal imaging cameras Flir and Optris, manipulated manually from the ground surface and also from unmanned aerial vehicle and piloted ultralight-plane platforms. The surveys were conducted during cold days of winter 2014/2015 and early in the morning to avoid the negative effect of direct sunshine. The first study site is the Bad Fischau rockslide in the southern part of the Vienna Basin (Austria). It was firstly identified by the morphostructural analysis of 1-m digital terrain model from the airborne laser scan data. The rockslide is superimposed on, and closely related to the active marginal faults of the Vienna basin, which is a pull apart structure. There is the 80-m-deep Eisenstein Show Cave situated in the southern lateral margin of the rockslide. The cave was originally considered to be purely of hydrothermal (hypogene) karstification; however its specific morphology and position within the detachment zone of the rockslide suggests its relation to gravitational slope-failure. The IRT survey revealed the Eisenstein Cave at the ground surface and also several other open cracks and possible cleft caves along the margins, headscarp, and also within the body of the rockslide. The second surveyed site was the Kněhyně rockslide in the flysch belt of the Outer Western Carpathians in the eastern Czech Republic. This deep-seated translational rockslide formed about eight known pseudokarst crevice caves, which reach up to 57 m in depth. The IRT survey recognized several warm anomalies indicating very deep

  15. Detecting surface changes of slope to channel coupling in an alpine catchment using terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Rascher, Eric; Sass, Oliver

    2015-04-01

    Understanding the evolution and functions of a river system and interpreting the morphology and the dynamics of the channel is a key factor in fluvial geomorphology. For this purpose it is essential to analyse the processes of sediment input and output within and between river reaches and to detect the various forms of storage types on hillslopes and in the channel network. From these processes catchment scale sediment fluxes are derived and result in sediment budgets showing the amount and motion of sediment through the system. Sediment connectivity is a highly important characteristic of catchments when sediment transfer processes are studied. In this context, connectivity controls the sediment fluxes throughout the landscape which means the transfer of sediment from sediment sources to sinks and particularly the potential of a particle to move through the system. This study focuses on slope to channel coupling in the Johnsbach Valley, a typical, non-glaciated alpine catchment in the eastern Austrian Alps. The valley covers an area of 65 km² with altitudes ranging from 584 m a.s.l. at the outlet to 2369 m a.s.l. (Hochtor). The valley is drained by the Johnsbach River which originates in a crystalline bedrock dominated part of the catchment. After approximately 10 km of the distance downstream the lithology changes to calcareous bedrock. In this part of the Johnsbach Valley most of the sediment contributing areas are situated. To detect slope to channel coupling surface changes were measured and mass balances were quantified by terrestrial laser scanning using a RIEGL LMS-Z620. Four field sites were chosen were side channels are directly connected to the main fluvial system. Additionally two field sites show sediment movement in between the side channels. Field campaigns were carried out in September and October of 2013 as well as in April, July, August and October of 2014. First results show that sediment contribution from the side channels and erosion of

  16. Observations of drainage network change in a recently burned watershed using terrestrial laser scanning

    USGS Publications Warehouse

    Staley, Dennis; Wasklewicz, Thad; Kean, Jason

    2010-01-01

    Wildfire enhances the geomorphic response of a watershed to precipitation events, effectively altering the form of the hillslope and channel drainage network. Typically, drainage networks expand following rainfall on a recently burned watershed. Expansion of drainage networks following wildfire increases in erosion and sediment transport rates, and the probability of flash-flooding and debris-flows at downstream locations. Observations of the response of hillslope and channel drainage to individual precipitation events are vital to unraveling the dynamics of erosion processes in recently burned watersheds. Here, we apply terrestrial laser scanning (TLS) methods to produce digital terrain models (DTMs) of a recently burned watershed at an unprecedented spatial resolution. The DTM data aid the quantification of changes in the hillslope and channel drainage networks at several spatial scales. Two TLS surveys were conducted, one survey between 28-30 September 2008 to document pre-rainfall conditions, and one between 18-21 December 2008, three days after 52 mm of rainfall over a period of 22 hours. A Leica Geosystems ScanStation 2 TLS was used to generate 1 cm resolution DTMs, from which the hillslope and channel drainage networks were derived. The location and magnitude of erosion and deposition for each pixel within the basin was determined by calculating the topographic differences between DTMs. Changes in the drainage network morphology were identified through the analysis of bifurcation ratio, drainage density (including rills), rill length, horizontal migration of rills, width-depth ratios and upstream migration of knickpoints. Comparisons of these measures were made between morphologically distinct sub-basins within the study area, and between surveys. Analyses of bifurcation ratios, and measures of rill position and gullyhead migration indicate an expansion of the rill network and upstream migration of knickpoints. These results suggest that expansion of the

  17. Sampling and modeling of rock discontinuities by terrestrial laser scanning and photogrammetry in railway environment

    NASA Astrophysics Data System (ADS)

    Assali, P.; Grussenmeyer, P.; Pollet, N.; Viguier, F.; Villemin, T.

    2012-04-01

    In order to increase its knowledge of rock slope stability along the French national rail network, the SNCF Engineering Management is developing a new approach for sampling and modeling rock discontinuities. The rock face diagnosis is a follow-up and check operation of the field works. This operation allowed to optimize the rock risk treatment at the best price in respect with safety requirements. These operations require the measurement of orientation and location of rock discontinuities at the surface of the rock mass and is followed by a structural modeling in order to extrapolate the data collected at the surface to the inner part of the massif. At present, this work is completed manually with a compass-clinometer, in a simplified way mainly based on the specialist's experience. The analysis remains empirical, and most of the time restricted to the most fractured zone, whereas safety requirements ask for an exhaustive study on the whole of the site. Filling these gaps, the combined use of dense three-dimensional measurement techniques, associating both terrestrial laser scanning and optical imaging, makes it possible to obtain a more complete structural statement. The data acquisition and processing need protocols adapted to the railway environment for obtaining suitable 3D models. Then the exploitation of these models requires the development of semi-automatic process, with an aim of, to support the geologist's on-site expertise with a digital model exploitation. The geometrical characterization of the rock mass is undertaken thanks to a classification of the model in several subsets corresponding to the main directional families. The data on these planar discontinuities, traditionally acquired manually in certain points necessarily accessible of the rock face, result now from dense 3D models covering the whole of the work. Therefore, statistical sampling is stronger, while the time of the on-site survey is reduced. By these means, the diagnosis should be made

  18. 4D Analysis of Slope Monitoring Data from Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Williams, J.; Rosser, N. J.; Hardy, R. J.; Afana, A.

    2014-12-01

    Analysis of deformation from actively failing slopes is essential for gaining insight into the rates, mechanisms and controls on failure. Recent models have focussed upon the temporal evolution of failures, the validation of which requires increasingly high-resolution, high-frequency monitoring data. Since its introduction to geomorphological study, Terrestrial Laser Scanning (TLS) has become a frequently used means of characterising change to failing slopes. The most computationally efficient approach represents change on a pixel-by-pixel basis using rasterised 2.5D DEMs of Difference; however, the level of detail reduces on steep surfaces and the use of a fixed grid spacing limits the ability to resolve fine-scaled features, both of which may underpin failure mechanisms. A number of algorithms and software packages have been developed to better characterise surface and joint structures using 'true 3D' point clouds; however, 3D change detection with a large number of scans remains limited. In addition to developments in geometric change detection, TLS systems now provide radiometric information by digitising the energy-time structure of the reflected laser pulse, sensitive to surface moisture amongst other variables. This study draws upon a unique dataset of > 800 sequential scans captured across a failing rock slope. Our algorithm extracts change between a large number of scans, using a Moving Least Squares adjustment to filter data through time and space. The analysis explores optimal kernel structures for retaining spatial resolution and temporal responsiveness to articulate the nature of change in rock slopes, distinguishing discrete failures (e.g. rockfalls) from ongoing deformation (e.g. creep). The code segments successive clouds into an octree structure of planar surfaces and provides 3D change metrics through time. We use the code to test the ability to separate movement at various scales, with the aim of capturing movements suited for failure

  19. 3D change detection at street level using mobile laser scanning point clouds and terrestrial images

    NASA Astrophysics Data System (ADS)

    Qin, Rongjun; Gruen, Armin

    2014-04-01

    Automatic change detection and geo-database updating in the urban environment are difficult tasks. There has been much research on detecting changes with satellite and aerial images, but studies have rarely been performed at the street level, which is complex in its 3D geometry. Contemporary geo-databases include 3D street-level objects, which demand frequent data updating. Terrestrial images provides rich texture information for change detection, but the change detection with terrestrial images from different epochs sometimes faces problems with illumination changes, perspective distortions and unreliable 3D geometry caused by the lack of performance of automatic image matchers, while mobile laser scanning (MLS) data acquired from different epochs provides accurate 3D geometry for change detection, but is very expensive for periodical acquisition. This paper proposes a new method for change detection at street level by using combination of MLS point clouds and terrestrial images: the accurate but expensive MLS data acquired from an early epoch serves as the reference, and terrestrial images or photogrammetric images captured from an image-based mobile mapping system (MMS) at a later epoch are used to detect the geometrical changes between different epochs. The method will automatically mark the possible changes in each view, which provides a cost-efficient method for frequent data updating. The methodology is divided into several steps. In the first step, the point clouds are recorded by the MLS system and processed, with data cleaned and classified by semi-automatic means. In the second step, terrestrial images or mobile mapping images at a later epoch are taken and registered to the point cloud, and then point clouds are projected on each image by a weighted window based z-buffering method for view dependent 2D triangulation. In the next step, stereo pairs of the terrestrial images are rectified and re-projected between each other to check the geometrical

  20. Optimization of the design of a multiple-photon excitation laser scanning fluorescence imaging system

    NASA Astrophysics Data System (ADS)

    Wokosin, David L.; White, John G.

    1997-04-01

    Multi-photon (two or more photon) excitation imaging offers three significant advantages compared to laser-scanning confocal fluorescence microscopy for 3-D and 4-D fluorescence microscopy: considerable reduction in total sample excitation, increased depth penetration, and increased detection sensitivity. All-solid-state ultra-fast lasers offer tremendous potential for affordable, reliable, 'turn-key' multi-photon excitation sources. We have been developing a multi-photon system that utilizes an all-solid- state Nd:YLF excitation source. We have been evaluating the potential of this source for biological microscopy and have been optimizing system parameters for this application area. We have found that the 1047 nm radiation from these lasers can excite by two-photon fluorescence many commonly used fluorophores that are normally excited from blue to yellow light. In addition, we have found that this wavelength readily excites several normally UV excited fluorophores by the mechanism of three-photon excitation. The Nd:YLF laser has proven reliable in operation with nearly 6000 hours logged without significant loss of power. However, the original system produced rather long pulses for multi-photon excitation (300 fs) and a beam shape that was not ideal. We have recently commissioned the development of an improved pulse compressor from the manufacturers that gives narrower pulses (120 fs), improved beam shape, and a smaller insertion loss. This optimized excitation system has 6 times more potential two-photon excited fluorescence and 22 times more potential three-photon excited fluorescence than the prototype system. In addition, by optimizing coatings in the excitation and signal paths, we have improved the descanned detection sensitivity by 20% for two-photon excited fluorescence and 315% for three-photon excited fluorescence. The excitation optical transfer efficiency (1047 nm) of our imaging system is currently 60% to the back aperture of the objective. The

  1. The fusion of terrestrial laser scanning and optical bathymetric mapping to monitor braided river morphodynamics

    NASA Astrophysics Data System (ADS)

    Williams, R. D.; Brasington, J.; Vericat, D.; Hicks, M.

    2011-12-01

    In recent years, Terrestrial Laser Scanning (TLS) has emerged as a new technology that has transformative potential for mapping morphological change in braided rivers. TLS makes it possible to acquire precise, reach-scale topographic datasets that can be used to recover centimeter scale channel morphology. When coupled with a suitable bathymetric mapping technique, high-resolution Digital Elevation Models (DEMs) can be produced for both wet and dry areas of the braidplain. Since TLS surveys can be undertaken at frequencies commensurate with individual flood events, sequences of DEMs can then be used to investigate sediment transport rates, using the morphological approach. In turn, these reach-scale datasets can be used to understand braided river morphodynamics and to provide boundary conditions for morphodynamic modeling. A unique dataset that records the evolution of a 2.5 x 0.7 km braided reach of the Rees River, New Zealand, from September 2009 to May 2010, has recently been generated. Topographic data were acquired after ten flood events, using a combination of two remote sensing methodologies. Dry areas of the braidplain were surveyed using TLS with dual-frequency GPS mounted on an Argo Amphibious All Terrain Vehicle. Bathymetry was mapped using an empirically calibrated optical method, based on non-metric vertical aerial photos acquired from a helicopter and an acoustic depth survey along primary anabranches. The availability of the Rees River dataset provides a sequence of braided rivers DEMs that are unprecedented in their three-dimensional resolution, precision and spatial extent. In this paper we describe the methodology that has been developed to monitor the evolution of the Rees River. DEMs were produced using a three step process that involved (i) the construction of ground level DEMs from TLS data; (ii) the derivation of water surface elevations; and (iii) the mapping of channel bed levels using optical bathymetric mapping. The morphological change

  2. Monitoring gully-head propagation with terrestrial laser scanning, West Bijou Creek, Colorado (Invited)

    NASA Astrophysics Data System (ADS)

    Tucker, G. E.; Phillips, D. A.; Martinez Torres, F. A.; Feliciano Bonilla, E. A.; Sheehan, A. F.

    2009-12-01

    Arid and semi-arid landscapes are often laced with rapidly evolving networks of ephemeral gullies. These gully networks can act as significant sources of fine sediment, and their growth can undermine road systems, agricultural works, and other forms of infrastructure. In addition to these practical considerations, gullies are of great scientific interest as integral components of evolving landscapes. Yet the physics driving gully network evolution remain rather poorly understood at a quantitative level, raising questions such as how a gullied landscape might respond to changing climate or land cover. Here we report results from an integrated study of gully dynamics on the high plains of Colorado, USA. Gullies in the study area are typically bounded at their upper end by one- to two-meter high head scarps, and grade downstream into broad, unchanneled valleys. Analysis of historical aerial photographs reveals that gully head scarps in the study area have propagated at average rates on the order of decimeters per year over the past several decades. However, the timing and nature of the retreat processes are unknown. Traditionally, data on contemporary gully erosion rates are obtained using simple, single-point measurements of the distance of the channel head from a known benchmark. However, this method provides no information about spatial patterns of landform erosion or the volume of eroded material. In order to address these issues, high-resolution terrestrial laser scans (TLS) of a typical large gully head were collected in the summers of 2008 and 2009. Difference images between the two scans reveal a zone of concentrated erosion of up to 50cm depth along one meter-scale portion of the active head scarp. Other regions of the scarp face showed relatively little detectable change. The net erosion pattern emerged despite the existence of decimeter-scale noise originating from the grassland vegetation cover, demonstrating that TLS technology is applicable to active

  3. Practical aspects of registration the transformation of a river valley by beavers using terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Tyszkowski, Sebastian; Błaszkiewicz, Mirosław; Brykała, Dariusz; Gierszewski, Piotr; Kaczmarek, Halina; Kordowski, Jarosław; Słowiński, Michał

    2016-04-01

    Activity of beavers (Castor fiber) often significantly affects the environment in which they life. The most commonly observed effect of their being in environment is construction of beaver dams and formation a pond upstream. However, in case of a sudden break of a dam and beaver pond drainage, the valley below the dam may also undergo remodelling. The nature and magnitude of these changes depends on the quantity of water and its energy as well as on the geological structure of the valley. The effects of such events can be riverbank erosion, and the deposition of the displaced of erosion products in the form of sandbars or fans. The material can also be accumulated in local depressions or delivered to water bodies. Such events may occur multiple times in the same area. To assess their impact on the environment it is important to quantify the displaced material. The study of such transformations was performed within a small valley of the river of Struga Czechowska (Tuchola Pinewood Forest, Poland). The valley is mainly cut in sands and gravels. Its steep banks are overgrown with bushes and trees. The assessment of changes in morphology were based on the event of the beaver pond drainage of 2015. The study uses the measurements from the terrestrial laser scanning (scanner Riegl VZ-4000). The measurements were performed before and after the event. Each of the two models obtained for comparison was made up of more than 20 measurement stations. Point clouds were joined by Multi-Station Adjustment without placing in the terrain any objects of reference. During measurements attention was paid to the changes in morphology of both riverbed and valley surrounding. The paper presents the example of the recorded changes as well as the measurement procedure. Moreover, the aspects of fieldwork and issues related to post-processing, such as merging, filtering of point clouds and detection of changes, are also presented. This study is a contribution to the Virtual Institute of

  4. Mapping of local-scale flooding on vegetated floodplains from radiometrically calibrated airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Malinowski, Radosław; Höfle, Bernhard; König, Kristina; Groom, Geoffrey; Schwanghart, Wolfgang; Heckrath, Goswin

    2014-05-01

    The agricultural use of riverine lowlands is often dependent on complex hydrological regimes including localized flooding. Knowledge about spatio-temporal inundation patterns enables a better understanding of the state of agricultural areas in lowlands and provides valuable and objective information on land suitability for land use administration and environmental planning. Data from Airborne Laser Scanning (ALS), also referred to as LiDAR, have become one of the most important sources of elevation data during the last two decades. Recently, geometric and radiometric attributes of ALS have also been explored for analysing the extent of water surfaces. Thus, the main objective of this work is to develop a method for mapping the spatial extent of floodplain inundation by means of remote sensing data. Our study focusses on analysing floodwaters partly covered by some vegetation, which is a major challenge in flood mapping. We hypothesize that ALS data due to its high sampling density and high rate of canopy penetration can effectively be used for floodwater detection in such areas. This research utilizes full-waveform ALS data with an average point density of 20 points/m2 obtained for an area of ca. 8 km2 of the Nørreå River valley in Jutland, Denmark. The study area is characterised by the presence of improved or semi-improved grasslands (meadows and pasture), few arable fields, irregularly scattered group of trees and bushes, and an extensive ditch network. Our approach is based on an inspection of properties of single laser points with regard to water vs. vegetation coverage within the laser footprint, which is compared with very detailed field reference data. Exploratory analysis and classification of ALS data were preceded by radiometric calibration of point cloud data, utilizing in situ measurements of reference targets reflectance. The resulting calibration derivatives provide very stable estimates of surface characteristics and are used as the main input in

  5. The Echo Cliffs Precariously Balanced Rock; Discovery and Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Hudnut, K. W.; Amidon, W. H.; Bawden, G. W.; Brune, J. N.; Bond, S.; Graves, R. W.; Haddad, D. E.; Limaye, A.; Lynch, D. K.; Phillips, D. A.; Pounders, E.; Rood, D. H.

    2009-12-01

    We investigate a previously undocumented Precariously Balanced Rock (PBR) located above Echo Cliffs in the western Santa Monica Mountains, using Terrestrial Laser Scanning (TLS). We present the merged and aligned point cloud of TLS data (over 42 million points) and photos to document the Echo Cliffs PBR site. We also present our interpretations of the site, of its geomorphic development, and its possible significance for seismic hazards in the Los Angeles region. The rock lies above the ramp in the fault propagation fold structure that has been interpreted by Davis and Namson as an active structure that may pose a major seismic hazard to the Los Angeles area. The Echo Cliffs PBR stands at just over 14 meters in height, so assuming it acts as an inverse pendulum, it has a 3 to 4 second period of oscillation. This period corresponds to the oscillatory period of a 30 to 40 story building. The rock withstood ground motions during the 1994 Northridge earthquake that we estimate to have been 0.2 g (PGA) and 12 cm/sec (PGV) at this site. It is expected that the Echo Cliffs PBR may provide important constraints on scenario ground motions and thereby improve future simulations. We believe that this is the first application of TLS methods on PBR's, and we find that the high resolution provided by TLS allows us to characterize the detailed shape of the PBR itself, as well as key details of the interface between the rock and pedestal at the cm-level. In addition, the cliff band near the PBR and the geomorphic context of the surrounding hill slope area was also scanned at a coarser resolution, providing data that help to understand the processes by which the PBR formed. An advantage of TLS is that it provides an image of the outline of the rock-pedestal contact surface and adjacent non-contacting surfaces. The TLS also helps quantify the effects of shielding on cosmogenic nuclide production, enhancing the accuracy of our surface exposure age dating.

  6. Characterizing the geomorphic setting of precariously balanced rocks using terrestrial laser scanning technology

    NASA Astrophysics Data System (ADS)

    Haddad, D. E.; Arrowsmith, R.

    2009-12-01

    Terrestrial laser scanning (TLS) technology is rapidly becoming an effective three-dimensional imaging tool. Precariously balanced rocks are a subset of spheroidally weathered boulders. They are balanced on bedrock pedestals and are formed in upland drainage basins and pediments of exhumed plutons. Precarious rocks are used as negative evidence of earthquake-driven extreme ground motions. Field surveys of PBRs are coupled with cosmogenic radionuclide (CRN) surface exposure dating techniques to determine their exhumation rates. These rates are used in statistical simulations to estimate the magnitudes and recurrences of earthquake-generated extreme ground shaking as a means to physically validate seismic hazard analyses. However, the geomorphic setting of PBRs in the landscape is poorly constrained when interpreting their exhumation rates from CRN surface exposure dates. Are PBRs located on steep or gentle hillslopes? Are they located near drainages or hillslope crests? What geomorphic processes control the spatial distribution of PBRs in a landscape, and where do these processes dominate? Because the fundamental hillslope transport laws are largely controlled by local hillslope gradient and contributing area, the location of a PBR is controlled by the geomorphic agents and their rates acting on it. Our latest efforts involve using a combination of TLS and airborne laser swath mapping (ALSM) to characterize the geomorphic situation of PBRs. We used a Riegl LPM 800i (LPM 321) terrestrial laser scanner to scan a ~1.5 m tall by ~1 m wide precariously balanced rock in the Granite Dells, central Arizona. The PBR was scanned from six positions, and the scans were aligned to a point cloud totaling 3.4M points. We also scanned a ~50 m by ~150 m area covering PBR hillslopes from five scan positions. The resulting 5.5M points were used to create a digital terrain model of precarious rocks and their hillslopes. Our TLS- and ALSM-generated surface models and DEMs provide a

  7. Quantitative assessment of automatic reconstructions of branching systems obtained from laser scanning

    PubMed Central

    Boudon, Frédéric; Preuksakarn, Chakkrit; Ferraro, Pascal; Diener, Julien; Nacry, Philippe; Nikinmaa, Eero; Godin, Christophe

    2014-01-01

    Background and Aims Automatic acquisition of plant architecture is a major challenge for the construction of quantitative models of plant development. Recently, 3-D laser scanners have made it possible to acquire 3-D images representing a sampling of an object's surface. A number of specific methods have been proposed to reconstruct plausible branching structures from this new type of data, but critical questions remain regarding their suitability and accuracy before they can be fully exploited for use in biological applications. Methods In this paper, an evaluation framework to assess the accuracy of tree reconstructions is presented. The use of this framework is illustrated on a selection of laser scans of trees. Scanned data were manipulated by experienced researchers to produce reference tree reconstructions against which comparisons could be made. The evaluation framework is given two tree structures and compares both their elements and their topological organization. Similar elements are identified based on geometric criteria using an optimization algorithm. The organization of these elements is then compared and their similarity quantified. From these analyses, two indices of geometrical and structural similarities are defined, and the automatic reconstructions can thus be compared with the reference structures in order to assess their accuracy. Key Results The evaluation framework that was developed was successful at capturing the variation in similarities between two structures as different levels of noise were introduced. The framework was used to compare three different reconstruction methods taken from the literature, and allowed sensitive parameters of each one to be determined. The framework was also generalized for the evaluation of root reconstruction from 2-D images and demonstrated its sensitivity to higher architectural complexity of structure which was not detected with a global evaluation criterion. Conclusions The evaluation framework

  8. Use of terrestrial laser scanning data to drive decimetric resolution urban inundation models

    NASA Astrophysics Data System (ADS)

    Sampson, Christopher C.; Fewtrell, Timothy J.; Duncan, Alastair; Shaad, Kashif; Horritt, Matthew S.; Bates, Paul D.

    2012-06-01

    The advent of airborne LIDAR sparked a renewed research drive in two-dimensional hydraulic modelling at the turn of the millennium due to its ability to rapidly generate accurate DEMs over wide areas. Terrestrial LIDAR applies the same principle but uses a mobile ground-based platform, allowing rapid collection of terrain data in urban areas at decimetric scale. Here we apply two computationally efficient hydraulic models to DEMs of a small urban test site in Alcester, UK, derived from terrestrial and airborne LIDAR data at 10 cm and 1 m scales. The first model, LISFLOOD-FP, is a 2D raster-based model employing a simplified formulation of the de St. Venant equations, whilst the second model, ISIS-FAST, employs a proprietary rapid flood spreading algorithm. The response of the models to changes in DEM resolution and data source are analysed and compared across two event scales. For the first time we show that a flood wave propagating across an urban domain responds to small scale topographic features, such as street kerbs and road surface camber, which are not represented in airborne data but which are resolved by the terrestrial laser scanner. Importantly these features are preserved even if the 10 cm terrestrial data are degraded to the 1 m scale of the airborne DEM. The results indicate that inclusion of these features improves the representation of hydraulic connectivity over the DEM, and hence flood risk estimation. LISFLOOD-FP is shown to be more robust to changes in DEM resolution than ISIS-FAST due to the momentum conservation inherent to the simplified shallow water formulation, but the reduced computational requirements of ISIS-FAST at 10 cm scale allow it to be used for ensemble simulations. The extra detail inherent in terrestrial laser scanning data is advantageous where accurate representation of surface features is required, with potential benefit to high asset-value flood risk analysis and future studies into coupled surface/sewer and pluvial urban

  9. See-Through Imaging of Laser-Scanned 3d Cultural Heritage Objects Based on Stochastic Rendering of Large-Scale Point Clouds

    NASA Astrophysics Data System (ADS)

    Tanaka, S.; Hasegawa, K.; Okamoto, N.; Umegaki, R.; Wang, S.; Uemura, M.; Okamoto, A.; Koyamada, K.

    2016-06-01

    We propose a method for the precise 3D see-through imaging, or transparent visualization, of the large-scale and complex point clouds acquired via the laser scanning of 3D cultural heritage objects. Our method is based on a stochastic algorithm and directly uses the 3D points, which are acquired using a laser scanner, as the rendering primitives. This method achieves the correct depth feel without requiring depth sorting of the rendering primitives along the line of sight. Eliminating this need allows us to avoid long computation times when creating natural and precise 3D see-through views of laser-scanned cultural heritage objects. The opacity of each laser-scanned object is also flexibly controllable. For a laser-scanned point cloud consisting of more than 107 or 108 3D points, the pre-processing requires only a few minutes, and the rendering can be executed at interactive frame rates. Our method enables the creation of cumulative 3D see-through images of time-series laser-scanned data. It also offers the possibility of fused visualization for observing a laser-scanned object behind a transparent high-quality photographic image placed in the 3D scene. We demonstrate the effectiveness of our method by applying it to festival floats of high cultural value. These festival floats have complex outer and inner 3D structures and are suitable for see-through imaging.

  10. Airborne Laser Scanning - based vegetation classification in grasslands: a feasibility study

    NASA Astrophysics Data System (ADS)

    Zlinszky, András; Vári, Ágnes; Deák, Balázs; Mücke, Werner; Székely, Balázs

    2013-04-01

    Airborne Laser Scanning is traditionally used for topography mapping, exploiting its ability to map terrain elevation under vegetation cover. Parallel to this, the application of ALS for vegetation classification and mapping of ecological variables is rapidly emerging. Point clouds surveyed by ALS provide accurate representations of vegetation structure and are therefore considered suitable for mapping vegetation classes as long as their vertical structure is characteristic. For this reason, most ALS-based vegetation mapping studies have been carried out in forests, with some rare applications for shrublands or tall grass vegetation such as reeds. The use of remote-sensing derived vegetation maps is widespread in ecological research and is also gaining importance in practical conservation. There is an increasing demand for reliable, high-resolution datasets covering large protected areas. ALS can provide both the coverage and the high resolution, and can prove to be an economical solution due to the potential for automatic processing and the wide range of uses that allows spreading costs. Grasslands have a high importance in nature conservation as due to the drastical land use changes (arable lands, afforestation, fragmentation by linear structures) in the last centuries the extent of these habitats have been considerably reduced. Among the habitat types protected by the Habitat Directive of the Natura 2000 system, several grassland habitat types (e.g. hay meadows, dry grasslands harbouring rare Orchid species) have special priority for conservation. For preserving these habitat types application of a proper management - including mowing or grazing - has a crucial role. Therefore not only the mapping of the locations of habitats but the way of management is needed for representing the natural processes. The objective of this study was to test the applicability of airborne laser scanning for ecological vegetation mapping in and around grasslands. The study site is

  11. Multiplex fluorescence in situ hybridization (M-FISH) and confocal laser scanning microscopy (CLSM) to analyze multispecies oral biofilms.

    PubMed

    Karygianni, Lamprini; Hellwig, Elmar; Al-Ahmad, Ali

    2014-01-01

    Multiplex fluorescence in situ hybridization (M-FISH) constitutes a favorable microbiological method for the analysis of spatial distribution of highly variable phenotypes found in multispecies oral biofilms. The combined use of confocal laser scanning microscopy (CLSM) produces high-resolution three-dimensional (3D) images of individual bacteria in their natural environment. Here, we describe the application of M-FISH on early (Streptococcus spp., Actinomyces naeslundii) and late colonizers (Fusobacterium nucleatum, Veillonella spp.) of in situ-formed oral biofilms, the acquisition of CLSM images, as well as the qualitative and quantitative analysis of these digitally obtained and processed images. PMID:24664826

  12. Multiple-entity based classification of airborne laser scanning data in urban areas

    NASA Astrophysics Data System (ADS)

    Xu, S.; Vosselman, G.; Oude Elberink, S.

    2014-02-01

    There are two main challenges when it comes to classifying airborne laser scanning (ALS) data. The first challenge is to find suitable attributes to distinguish classes of interest. The second is to define proper entities to calculate the attributes. In most cases, efforts are made to find suitable attributes and less attention is paid to defining an entity. It is our hypothesis that, with the same defined attributes and classifier, accuracy will improve if multiple entities are used for classification. To verify this hypothesis, we propose a multiple-entity based classification method to classify seven classes: ground, water, vegetation, roof, wall, roof element, and undefined object. We also compared the performance of the multiple-entity based method to the single-entity based method. Features have been extracted, in most previous work, from a single entity in ALS data; either from a point or from grouped points. In our method, we extract features from three different entities: points, planar segments, and segments derived by mean shift. Features extracted from these entities are inputted into a four-step classification strategy. After ALS data are filtered into ground and non-ground points. Features generalised from planar segments are used to classify points into the following: water, ground, roof, vegetation, and undefined objects. This is followed by point-wise identification of the walls and roof elements using the contextual information of a building. During the contextual reasoning, the portion of the vegetation extending above the roofs is classified as a roof element. This portion of points is eventually re-segmented by the mean shift method and then reclassified. Five supervised classifiers are applied to classify the features extracted from planar segments and mean shift segments. The experiments demonstrate that a multiple-entity strategy achieves slightly higher overall accuracy and achieves much higher accuracy for vegetation, in comparison to the

  13. Airborne laser scanning based quantification of dead-ice melting in recently deglaciated terrain

    NASA Astrophysics Data System (ADS)

    Klug, C.; Sailer, R.; Schümberg, M.; Stötter, J.

    2012-04-01

    Dead-ice is explained as stagnant glacial ice, not influenced by glacier flow anymore. Whenever glaciers have negative mass balances and an accumulation of debris-cover on the surface, dead-ice may form. Although, there are numerous conceptual process-sediment-landform models for the melt-out of dead-ice bodies and areas of dead-ice environments at glacier margins are easily accessible, just a few quantitative studies of dead-ice melting have been carried out so far. Processes and rates of dead-ice melting are commonly believed to be controlled by climate and debris-cover properties, but there is still a lack of knowledge about this fact. This study has a focus on the quantification of process induced volumetric changes caused by dead-ice melting. The research for this project was conducted at Hintereisferner (Ötztal Alps, Austria), Gepatschferner (Ötztal Alps, Austria) and Schrankar (Stubai Alps, Austria), areas for which a good data basis of ALS (Airborne Laser Scanning) measurements is available. 'Hintereisferner' can be characterized as a typical high alpine environment in mid-latitudes, which ranges between approximately 2250 m and 3740 m a.s.l.. The Hintereisferner region has been investigated intensively since many decades. Two dead ice bodies at the orographic right side and one at the orographic left side of the Hintereisferner glacier terminus (approx. at 2500 m to 2550 m a.s.l.) were identified. Since 2001, ALS measurements have been carried out regularly at Hintereisferner resulting in a unique data record of 21 ALS flight campaigns, allowing long-term explorations of the two dead-ice areas. The second study area of 'Gepatschferner' in the Kaunertal ranges between 2060 m and 3520 m a.s.l. and is the second largest glacier of Austria. Near the glacier tongue at the orographic right side a significant dead ice body has formed. The ALS data used for quantification include a period of time of 4 years (2006 - 2010). 'Schrankar' is located in the Western

  14. Segmentation-based determination of terrain points from full-waveform airborne laser scanning data

    NASA Astrophysics Data System (ADS)

    Mücke, Werner; Hollaus, Markus; Briese, Christian

    2010-05-01

    Airborne laser scanning (ALS), also referred to as airborne LiDAR (light detection and ranging), is a widely-used method for the 3D sampling of the earth's surface. The resulting point cloud is often used to derive digital terrain models (DTM). As a preliminary step for this purpose, the point cloud has to be classified into the points belonging to terrain and those that do not. This process, which is also referred to as filtering, can be carried out even in vegetated areas, provided the fact ground echoes are present and can reliably be recognized. Especially the classification of dense lower vegetation poses problems for standard filtering algorithms. Points within these vegetation structures might be included in the terrain point cloud, causing the resulting DTM surface to run above the actual terrain and therefore being incorrect. The latest generation of ALS systems, the so-called full-waveform (FWF) scanners, provide 3D point clouds with extended information, which can support the process for terrain point classification. In contrast to conventional ALS hardware, which is able to detect one or more consecutive discrete echoes, FWF digitizers are capable of detecting and storing the whole emitted and backscattered signal, the so-called waveform. In order to obtain the single echoes, i.e. 3D points representing the backscattering surface, the recorded waveform has to be reconstructed and a decomposition algorithm has to be applied. During this echo detection process, not only the range from the scanner to the illuminated target, but also additional parameters can be derived. Apart from the amplitude, which is as well available in discrete ALS systems, the width of the backscattered echo, also referred to as echo width, is obtained. In this way, besides the acquisition of the geometry in terms of height measurements, the point cloud produced with FWF technology provides additional knowledge about the scanned surface that can be exploited for digital terrain

  15. An interactive mapping tool for visualizing lacunarity of laser scanned point clouds

    NASA Astrophysics Data System (ADS)

    Kania, Adam; Székely, Balázs

    2016-04-01

    Lacunarity, a measure of the spatial distribution of the empty space in a certain model or real space over large spatial scales, is found to be a useful descriptive quantity in many fields using imagery, including, among others, geology, dentistry, neurology. Its application in ecology was suggested more than 20 years ago. The main problem of its application was the lack of appropriate high resolution data. Nowadays, full-waveform laser scanning, also known as FWF LiDAR, provides the tool for mapping the vegetation in unprecedented details and accuracy. Consequently, the lacunarity concept can be revitalized, in order to study the structure of the vegetation in this sense as well. Calculation of lacunarity, even if it is done in two dimensions (2D), is still has its problems: on one hand it is a number-crunching procedure, on the other hand, it produces 4D results: at each 3D point it returns a set of data that are function of scale. These data sets are difficult to visualize, to evaluate, and to compare. In order to solve this problem, an interactive mapping tool has been conceptualized that is designed to manipulate and visualize the data, lets the user set parameters for best visualization or comparison results. The system is able to load large amounts of data, visualize them as lacunarity curves, or map view as horizontal slices or in 3D point clouds coloured according to the user's choice. Lacunarity maps are presented as a series of (usually) horizontal profiles, e.g. rasters, which cells contain color-mapped values of selected lacunarity of the point cloud. As lacunarity is usually analysed in a series of successive windows sizes, the tool can show a series of rasters with sequentially animated lacunarity maps calculated for various window sizes. A very fast switching of colour schemes is possible to facilitate rapid visual feedback to better understand underlying data patterns exposed by lacunarity functions. In the comparison mode, two sites (or two areas

  16. Semi-automatic mapping of cultural heritage from airborne laser scanning using deep learning

    NASA Astrophysics Data System (ADS)

    Due Trier, Øivind; Salberg, Arnt-Børre; Holger Pilø, Lars; Tonning, Christer; Marius Johansen, Hans; Aarsten, Dagrun

    2016-04-01

    This paper proposes to use deep learning to improve semi-automatic mapping of cultural heritage from airborne laser scanning (ALS) data. Automatic detection methods, based on traditional pattern recognition, have been applied in a number of cultural heritage mapping projects in Norway for the past five years. Automatic detection of pits and heaps have been combined with visual interpretation of the ALS data for the mapping of deer hunting systems, iron production sites, grave mounds and charcoal kilns. However, the performance of the automatic detection methods varies substantially between ALS datasets. For the mapping of deer hunting systems on flat gravel and sand sediment deposits, the automatic detection results were almost perfect. However, some false detections appeared in the terrain outside of the sediment deposits. These could be explained by other pit-like landscape features, like parts of river courses, spaces between boulders, and modern terrain modifications. However, these were easy to spot during visual interpretation, and the number of missed individual pitfall traps was still low. For the mapping of grave mounds, the automatic method produced a large number of false detections, reducing the usefulness of the semi-automatic approach. The mound structure is a very common natural terrain feature, and the grave mounds are less distinct in shape than the pitfall traps. Still, applying automatic mound detection on an entire municipality did lead to a new discovery of an Iron Age grave field with more than 15 individual mounds. Automatic mound detection also proved to be useful for a detailed re-mapping of Norway's largest Iron Age grave yard, which contains almost 1000 individual graves. Combined pit and mound detection has been applied to the mapping of more than 1000 charcoal kilns that were used by an iron work 350-200 years ago. The majority of charcoal kilns were indirectly detected as either pits on the circumference, a central mound, or both

  17. Intercomparison of Terrestrial Laser Scanning Instruments for Assessing Forested Ecosystems: A Brisbane Field Experiment

    NASA Astrophysics Data System (ADS)

    Armston, J.; Newnham, G.; Strahler, A. H.; Schaaf, C.; Danson, M.; Gaulton, R.; Zhang, Z.; Disney, M.; Sparrow, B.; Phinn, S. R.; Schaefer, M.; Burt, A.; Counter, S.; Erb, A.; Goodwin, N.; Hancock, S.; Howe, G.; Johansen, K.; Li, Z.; Lollback, G.; Martel, J.; Muir, J.; Paynter, I.; Saenz, E.; Scarth, P.; Tindall, D.; Walker, L.; Witte, C.; Woodgate, W.; Wu, S.

    2013-12-01

    themes include retrieval of leaf area index and related parameters; retrieval of tree diameters, above-ground biomass, and height; approaches to calibration; waveform vs. discrete return data; value of dual wavelength data; ray tracing simulations driven by scanning; and others. This effort was initiated as an activity of the Terrestrial Laser Scanning International Interest Group. The primary objective of this international collaboration is to advance the understanding and application of TLS to forest management and inventory, rapid and automated measurement of vegetation structure parameters, monitoring vegetation dynamics, calibration and validation of large area above-ground biomass mapping, and the development of new low-cost portable scanners to enable wider application of these technologies. Immediate application of the data sets and techniques developed will be through national collaborative research programs, such as NEON and TERN, which enable the techniques and infrastructure developed to be applied consistently. These collaborations and the data and techniques developed and shared openly are essential to enable consistent production of forest structural property maps in science and management applications.

  18. Terrestrial laser scanning of anthropogenic beach berms for urban flood defense

    NASA Astrophysics Data System (ADS)

    Sanders, B. F.; Schubert, J.; Gallien, T.; Shakeri Majd, M.

    2013-12-01

    Globally, over 20 million people reside below present high tide levels and as many as 200 million are vulnerable to flooding during extreme events. In California, coastal flooding is driven by a combination of factors such as high astronomical tides, waves, storm surge, and other fluctuations such as those caused by the El Nino Southern Oscillation (ENSO), and climate change is likely to exacerbate those factors testing the limits of coastal flood defenses. Beaches provide natural flood protection during storms by mitigating the effects of high water levels and wave runup, and a process known as beach berming can be used to temporarily enhance the ability of beaches to withstand overtopping. In cases where beaches serve as primary protection for development, anthropogenic berms may represent an attractive management option for temporarily addressing future flood hazards. Terrestrial laser scanning (TLS) or lidar has emerged as a valuable technology for capturing the three dimensional geometry of complex surfaces and objects, and in the context of coastal flood prediction mobile TLS could prove invaluable by quickly mapping beach topography before an imminent flood threat and reducing associated uncertainties in coastal flood forecasting systems. The research presented here highlights the results of a field campaign to document the initial conditions and dynamic erosion of anthropogenic berms using TLS. On three occasions in February and March of 2012, a prototype berm was constructed on the foreshore of the city of Newport Beach, CA at low tide, and was scanned to document its initial shape, and then scanned in near-continuous fashion with the rising tide to characterize its subsequent erosion. The purpose is two-fold: (1) to measure the performance of the TLS system relative to accuracy and assess strengths and drawbacks that are likely to bear on the suitability of this technology to support flood prediction as described above, and (2) to develop a better

  19. Use of terrestrial laser scanning to characterize rock glacier surface morphology and deformation, Handcart Gulch, Colorado

    NASA Astrophysics Data System (ADS)

    Cuddus, Y.; Caine, J. S.

    2012-12-01

    While there has been extensive, recent research on the kinematics of rock glaciers, few studies have been able to examine surface deformation and strain utilizing terrestrial laser scanning (TLS). TLS captures a high precision, three-dimensional point cloud of X, Y, Z data. We scanned a portion of the Handcart Gulch Rock Glacier (HRG) surface at centimeter scale resolution (standard deviation of 0.64 cm). Although the origins of rock glacier formation and subsequent kinematics are poorly understood, the general consensus is that periglacial rock glaciers are a type of mass-driven permafrost that moves on the order of tens of cm per year. Velocity near the surface is thought to be faster than at depth, producing ridge- or moraine-like structures possibly formed by near-surface, compressional buckling. The HRG, located in Pike National Forest just below the Continental Divide, is multi-lobed and composed of hydrothermally altered Proterozoic metamorphic rock. In addition to commonly observed "compressional ridges", the rock glacier surface shows a number of scarp-like discontinuities that may be indicative of extension. The rock glacier surface has limited vegetative cover and a thin, but laterally extensive, layer of unidentified black lichen and lesser amounts of green Rhizocarpon lichen. The curviplanar scarps are up to about 4 m in height and are marked by discrete discontinuities that cut the lichen-covered rock glacier surface, revealing steeply dipping (> 35°) faces that are not covered with lichen. The lichen-covered surface appears to have been displaced, top-down in the direction of the maximum topographic gradient, and along the relatively lichen-free scarps thus resembling normal faults. Lichenometry is a useful method for providing a relative dating of rock glacial movement. Rhizocarpon is commonly used for dating due to its well documented, slow growth rate and ease of identification. After a century of growth the maximum diameter of Front Range

  20. Geodetic Imaging for Rapid Assessment of Earthquakes: Airborne Laser Scanning (ALS)

    NASA Astrophysics Data System (ADS)

    Carter, W. E.; Shrestha, R. L.; Glennie, C. L.; Sartori, M.; Fernandez-Diaz, J.; National CenterAirborne Laser Mapping Operational Center

    2010-12-01

    To the residents of an area struck by a strong earthquake quantitative information on damage to the infrastructure, and its attendant impact on relief and recovery efforts, is urgent and of primary concern. To earth scientists a strong earthquake offers an opportunity to learn more about earthquake mechanisms, and to compare their models with the real world, in hopes of one day being able to accurately predict the precise locations, magnitudes, and times of large (and potentially disastrous) earthquakes. Airborne laser scanning (also referred to as airborne LiDAR or Airborne Laser Swath Mapping) is particularly well suited for rapid assessment of earthquakes, both for immediately estimating the damage to infrastructure and for providing information for the scientific study of earthquakes. ALS observations collected at low altitude (500—1000m) from a relatively slow (70—100m/sec) aircraft can provide dense (5—15 points/m2) sets of surface features (buildings, vegetation, ground), extending over hundreds of square kilometers with turn around times of several hours to a few days. The actual response time to any given event depends on several factors, including such bureaucratic issues as approval of funds, export license formalities, and clearance to fly over the area to be mapped, and operational factors such as the deployment of the aircraft and ground teams may also take a number of days for remote locations. Of course the need for immediate mapping of earthquake damage generally is not as urgent in remote regions with less infrastructure and few inhabitants. During August 16-19, 2010 the National Center for Airborne Laser Mapping (NCALM) mapped the area affected by the magnitude 7.2 El Mayor-Cucapah Earthquake (Northern Baja California Earthquake), which occurred on April 4, 2010, and was felt throughout southern California, Arizona, Nevada, and Baja California North, Mexico. From initial ground observations the fault rupture appeared to extend 75 km

  1. Rock and stone weathering at Citadel fortifications, Gozo (Malta): benefits from terrestrial laser scanning combined with conventional investigations

    NASA Astrophysics Data System (ADS)

    Tapete, D.; Gigli, G.; Mugnai, F.; Vannocci, P.; Pecchioni, E.; Morelli, S.; Fanti, R.; Casagli, N.

    2012-04-01

    Military architecture heritage is frequently built on rock masses affected by slope instability and weathering processes, which progressively undermine the foundations and cause collapses and toppling of the masonries. The latter can be also weakened by alteration of the stone surfaces, as a consequence of the interactions with the local environmental conditions. These conservation issues are emphasized for those sites, whose susceptibility to structural damages is also due to the similarity between the lithotypes constituting the geologic substratum and the construction materials. Effective solutions for the protection from such a type of phenomena can be achieved if the whole "rock mass - built heritage system" is analyzed. In this perspective, we propose a new approach for the study of the weathering processes affecting historic hilltop sites, taking benefits from the combination of terrestrial laser scanning (TLS) and conventional investigations, the latter including geotechnical and minero-petrographic analyses. In particular, the results here presented were obtained from specific tests on the fortifications of Citadel, Gozo (Malta), performed in co-operation with the Restoration Unit, Works Division, Maltese Ministry for Resources and Rural Affairs and the private company Politecnica Ingegneria e Architettura. The Citadel fortifications are built at the top of a relatively stiff and brittle limestone plate, formed by Upper Coralline Limestone (UCL) and overlying a thick Blue Clay (BC) layer. Differential weathering creates extensively fractured ledges on the cap and erosion niches in the strata beneath, thereby favouring block detachment, even rockfall events, such as the last one occurred in 2001. The locally quarried Globigerina Limestone (GL), historically employed in restoration masonries, is also exposed to alveolization and powdering, and several collapses damaged the underwalling interventions. Since the erosion pattern distribution suggested a

  2. The determination of firing distance applying a microscopic quantitative method and confocal laser scanning microscopy for detection of gunshot residue particles.

    PubMed

    Neri, Margherita; Turillazzi, Emanuela; Riezzo, Irene; Fineschi, Vittorio

    2007-07-01

    In this study, we applied a microscopic quantitative method based on the use of sodium rhodizonate to verify the presence of residues and their distribution on the cutis of gunshot wounds. A total of 250 skin samples were selected from cases in which the manner of death (accidental, suicide, and homicide) and the shooting distance could be reliably determined. The samples were examined under a light microscope, in transmitted bright field illumination and phase contrast mode, and with confocal laser scanning microscopy. In all skin specimens the area of each histological section was directly measured by an image analysis system. Both the number and the size of powder particles were measured. The distribution of gunshot residues (GSR) in the epidermal and subepidermal layers was also analyzed. The evaluation of the microscopic entrance wounds demonstrated different findings related to the range of fire. The data derived from the evaluation of both macroscopic and microscopic features demonstrated that the amount and the spatial distribution of GSR deposits in the skin surrounding entrance wounds strictly correlate with shooting distance. PMID:16862444

  3. An endolithic microbial community in dolomite rock in central Switzerland: characterization by reflection spectroscopy, pigment analyses, scanning electron microscopy, and laser scanning microscopy.

    PubMed

    Horath, T; Neu, T R; Bachofen, R

    2006-04-01

    A community of endolithic microorganisms dominated by phototrophs was found as a distinct band a few millimeters below the surface of bare exposed dolomite rocks in the Piora Valley in the Alps. Using in situ reflectance spectroscopy, we detected chlorophyll a (Chl a), phycobilins, carotenoids, and an unknown type of bacteriochlorophyll-like pigment absorbing in vivo at about 720 nm. In cross sections, the data indicated a defined distribution of different groups of organisms perpendicular to the rock surface. High-performance liquid chromatography analyses of pigments extracted with organic solvents confirmed the presence of two types of bacteriochlorophylls besides chlorophylls and various carotenoids. Spherical organisms of varying sizes and small filaments were observed in situ with scanning electron microscopy and confocal laser scanning microscopy (one- and two-photon technique). The latter allowed visualization of the distribution of phototrophic microorganisms by the autofluorescence of their pigments within the rock. Coccoid cyanobacteria of various sizes predominated over filamentous ones. Application of fluorescence-labeled lectins demonstrated that most cyanobacteria were embedded in an exopolymeric matrix. Nucleic acid stains revealed a wide distribution of small heterotrophs. Some biological structures emitting a green autofluorescence remain to be identified. PMID:16598629

  4. Characterization of atopic skin and the effect of a hyperforin-rich cream by laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Meinke, Martina C.; Richter, Heike; Kleemann, Anke; Lademann, Juergen; Tscherch, Kathrin; Rohn, Sascha; Schempp, Christoph M.

    2015-05-01

    Atopic dermatitis (AD) is a multifactorial inflammatory skin disease that affects both children and adults in an increasing manner. The treatment of AD often reduces subjective skin parameters, such as itching, dryness, and tension, but the inflammation cannot be cured. Laser scanning microscopy was used to investigate the skin surface, epidermal, and dermal characteristics of dry and atopic skin before and after treatment with an ointment rich in hyperforin, which is known for its anti-inflammatory effects. The results were compared to subjective parameters and transepidermal water loss, stratum corneum moisture, and stratum corneum lipids. Using biophysical methods, in particular laser scanning microscopy, it was found that atopic skin has distinct features compared to healthy skin. Treatment with a hyperforin-rich ointment resulted in an improvement of the stratum corneum moisture, skin surface dryness, skin lipids, and the subjective skin parameters, indicating that the barrier is stabilized and improved by the ointment. But in contrast to the improved skin surface, the inflammation in the deeper epidermis/dermis often continues to exist. This could be clearly shown by the reflectance confocal microscopy (RCM) measurements. Therefore, RCM measurements could be used to investigate the progress in treatment of atopic dermatitis.

  5. Comparison of in vivo and ex vivo laser scanning microscopy and multiphoton tomography application for human and porcine skin imaging

    SciTech Connect

    Darvin, M E; Richter, H; Zhu, Y J; Meinke, M C; Knorr, F; Lademann, J; Gonchukov, S A; Koenig, K

    2014-07-31

    Two state-of-the-art microscopic optical methods, namely, confocal laser scanning microscopy in the fluorescence and reflectance regimes and multiphoton tomography in the autofluorescence and second harmonic generation regimes, are compared for porcine skin ex vivo and healthy human skin in vivo. All skin layers such as stratum corneum (SC), stratum spinosum (SS), stratum basale (SB), papillary dermis (PD) and reticular dermis (RD) as well as transition zones between these skin layers are measured noninvasively at a high resolution, using the above mentioned microscopic methods. In the case of confocal laser scanning microscopy (CLSM), measurements in the fluorescence regime were performed by using a fluorescent dye whose topical application on the surface is well suited for the investigation of superficial SC and characterisation of the skin barrier function. For investigations of deeply located skin layers, such as SS, SB and PD, the fluorescent dye must be injected into the skin, which markedly limits fluorescence measurements using CLSM. In the case of reflection CLSM measurements, the obtained results can be compared to the results of multiphoton tomography (MPT) for all skin layers excluding RD. CLSM cannot distinguish between dermal collagen and elastin measuring their superposition in the RD. By using MPT, it is possible to analyse the collagen and elastin structures separately, which is important for the investigation of anti-aging processes. The resolution of MPT is superior to CLSM. The advantages and limitations of both methods are discussed and the differences and similarities between human and porcine skin are highlighted. (laser biophotonics)

  6. Documenting a Complex Modern Heritage Building Using Multi Image Close Range Photogrammetry and 3d Laser Scanned Point Clouds

    NASA Astrophysics Data System (ADS)

    Vianna Baptista, M. L.

    2013-07-01

    Integrating different technologies and expertises help fill gaps when optimizing documentation of complex buildings. Described below is the process used in the first part of a restoration project, the architectural survey of Theatre Guaira Cultural Centre in Curitiba, Brazil. To diminish time on fieldwork, the two-person-field-survey team had to juggle, during three days, the continuous artistic activities and performers' intense schedule. Both technologies (high definition laser scanning and close-range photogrammetry) were used to record all details in the least amount of time without disturbing the artists' rehearsals and performances. Laser Scanning was ideal to record the monumental stage structure with all of its existing platforms, light fixtures, scenery walls and curtains. Although scanned with high-definition, parts of the exterior façades were also recorded using Close Range Photogrammetry. Tiny cracks on the marble plaques and mosaic tiles, not visible in the point clouds, were then able to be precisely documented in order to create the exterior façades textures and damages mapping drawings. The combination of technologies and the expertise of service providers, knowing how and what to document, and what to deliver to the client, enabled maximum benefits to the following restoration project.

  7. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

    PubMed Central

    Yuan, Liang (Leon); Herman, Peter R.

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

  8. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors.

    PubMed

    Yuan, Liang Leon; Herman, Peter R

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

  9. Comparison of in vivo and ex vivo laser scanning microscopy and multiphoton tomography application for human and porcine skin imaging

    NASA Astrophysics Data System (ADS)

    Darvin, M. E.; Richter, H.; Zhu, Y. J.; Meinke, M. C.; Knorr, F.; Gonchukov, S. A.; Koenig, K.; Lademann, J.

    2014-07-01

    Two state-of-the-art microscopic optical methods, namely, confocal laser scanning microscopy in the fluorescence and reflectance regimes and multiphoton tomography in the autofluorescence and second harmonic generation regimes, are compared for porcine skin ex vivo and healthy human skin in vivo. All skin layers such as stratum corneum (SC), stratum spinosum (SS), stratum basale (SB), papillary dermis (PD) and reticular dermis (RD) as well as transition zones between these skin layers are measured noninvasively at a high resolution, using the above mentioned microscopic methods. In the case of confocal laser scanning microscopy (CLSM), measurements in the fluorescence regime were performed by using a fluorescent dye whose topical application on the surface is well suited for the investigation of superficial SC and characterisation of the skin barrier function. For investigations of deeply located skin layers, such as SS, SB and PD, the fluorescent dye must be injected into the skin, which markedly limits fluorescence measurements using CLSM. In the case of reflection CLSM measurements, the obtained results can be compared to the results of multiphoton tomography (MPT) for all skin layers excluding RD. CLSM cannot distinguish between dermal collagen and elastin measuring their superposition in the RD. By using MPT, it is possible to analyse the collagen and elastin structures separately, which is important for the investigation of anti-aging processes. The resolution of MPT is superior to CLSM. The advantages and limitations of both methods are discussed and the differences and similarities between human and porcine skin are highlighted.

  10. Segmentation of Planar Surfaces from Laser Scanning Data Using the Magnitude of Normal Position Vector for Adaptive Neighborhoods

    PubMed Central

    Kim, Changjae; Habib, Ayman; Pyeon, Muwook; Kwon, Goo-rak; Jung, Jaehoon; Heo, Joon

    2016-01-01

    Diverse approaches to laser point segmentation have been proposed since the emergence of the laser scanning system. Most of these segmentation techniques, however, suffer from limitations such as sensitivity to the choice of seed points, lack of consideration of the spatial relationships among points, and inefficient performance. In an effort to overcome these drawbacks, this paper proposes a segmentation methodology that: (1) reduces the dimensions of the attribute space; (2) considers the attribute similarity and the proximity of the laser point simultaneously; and (3) works well with both airborne and terrestrial laser scanning data. A neighborhood definition based on the shape of the surface increases the homogeneity of the laser point attributes. The magnitude of the normal position vector is used as an attribute for reducing the dimension of the accumulator array. The experimental results demonstrate, through both qualitative and quantitative evaluations, the outcomes’ high level of reliability. The proposed segmentation algorithm provided 96.89% overall correctness, 95.84% completeness, a 0.25 m overall mean value of centroid difference, and less than 1° of angle difference. The performance of the proposed approach was also verified with a large dataset and compared with other approaches. Additionally, the evaluation of the sensitivity of the thresholds was carried out. In summary, this paper proposes a robust and efficient segmentation methodology for abstraction of an enormous number of laser points into plane information. PMID:26805849

  11. Terrestrial and Aerial Laser Scanning Data Integration Using Wavelet Analysis for the Purpose of 3D Building Modeling

    PubMed Central

    Kedzierski, Michal; Fryskowska, Anna

    2014-01-01

    Visualization techniques have been greatly developed in the past few years. Three-dimensional models based on satellite and aerial imagery are now being enhanced by models generated using Aerial Laser Scanning (ALS) data. The most modern of such scanning systems have the ability to acquire over 50 points per square meter and to register a multiple echo, which allows the reconstruction of the terrain together with the terrain cover. However, ALS data accuracy is less than 10 cm and the data is often incomplete: there is no information about ground level (in most scanning systems), and often around the facade or structures which have been covered by other structures. However, Terrestrial Laser Scanning (TLS) not only acquires higher accuracy data (1–5 cm) but is also capable of registering those elements which are incomplete or not visible using ALS methods (facades, complicated structures, interiors, etc.). Therefore, to generate a complete 3D model of a building in high Level of Details, integration of TLS and ALS data is necessary. This paper presents the wavelet-based method of processing and integrating data from ALS and TLS. Methods of choosing tie points to combine point clouds in different datum will be analyzed. PMID:25004157

  12. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

    NASA Astrophysics Data System (ADS)

    Yuan, Liang (Leon); Herman, Peter R.

    2016-02-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems.

  13. Utilizing Ground-based LiDAR (Terrestrial Laser Scanning) to estimate hydraulic roughness in gravel-bed rivers

    NASA Astrophysics Data System (ADS)

    Minear, J. T.; Wright, S. A.

    2012-12-01

    Roughness is one of the more difficult parameters to quantify in the field for hydraulic studies, partially because it occurs at a variety of scales (i.e. grain, unit and reach), and because individual roughness elements, such as trees, grass and sediment grains, are difficult to measure. Ground-based LiDAR (also known as Terrestrial Laser Scanning) is changing the collection of high-quality topographic datasets for a variety of scientific endeavors, including forestry, geomorphology and hydrology and can be used to quantify hydraulic roughness in the field. Using datasets collected from several rivers in California, we evaluate the use of ground-based LiDAR (also known as Terrestrial Laser Scanning) for estimating hydraulic roughness in gravel-bed rivers. From our initial measurements, in addition to topography, there are a number of useful parameters that can be collected quickly and efficiently with ground-based LiDAR, including some that are not explicitly considered by existing hydraulic equations.

  14. Detailed three-dimensional visualization of resilin in the exoskeleton of arthropods using confocal laser scanning microscopy.

    PubMed

    Michels, J; Gorb, S N

    2012-01-01

    Resilin is a rubber-like protein found in the exoskeleton of arthropods. It often contributes large proportions to the material of certain structures in movement systems. Accordingly, the knowledge of the presence and distribution of resilin is essential for the understanding of the functional morphology of these systems. Because of its specific autofluorescence, resilin can be effectively visualized using fluorescence microscopy. However, the respective excitation maximum is in the UV range, which is not covered by the lasers available in most of the modern commercial confocal laser scanning microscopes. The goal of this study was to test the potential of confocal laser scanning microscopy (CLSM) in combination with a 405 nm laser to visualize and analyse the presence and distribution of resilin in arthropod exoskeletons. The results clearly show that all resilin-dominated structures, which were visualized successfully using wide-field fluorescence microscopy (WFM) and a 'classical' UV excitation, could also be visualized efficiently with the proposed CLSM method. Furthermore, with the application of additional laser lines CLSM turned out to be very appropriate for studying differences in the material composition within arthropod exoskeletons in great detail. As CLSM has several advantages over WFM with respect to detailed morphological imaging, the application of the proposed CLSM method may reveal new information about the micromorphology and material composition of resilin-dominated exoskeleton structures leading to new insights into the functional morphology and biomechanics of arthropods. PMID:22142031

  15. Segmentation of Planar Surfaces from Laser Scanning Data Using the Magnitude of Normal Position Vector for Adaptive Neighborhoods.

    PubMed

    Kim, Changjae; Habib, Ayman; Pyeon, Muwook; Kwon, Goo-rak; Jung, Jaehoon; Heo, Joon

    2016-01-01

    Diverse approaches to laser point segmentation have been proposed since the emergence of the laser scanning system. Most of these segmentation techniques, however, suffer from limitations such as sensitivity to the choice of seed points, lack of consideration of the spatial relationships among points, and inefficient performance. In an effort to overcome these drawbacks, this paper proposes a segmentation methodology that: (1) reduces the dimensions of the attribute space; (2) considers the attribute similarity and the proximity of the laser point simultaneously; and (3) works well with both airborne and terrestrial laser scanning data. A neighborhood definition based on the shape of the surface increases the homogeneity of the laser point attributes. The magnitude of the normal position vector is used as an attribute for reducing the dimension of the accumulator array. The experimental results demonstrate, through both qualitative and quantitative evaluations, the outcomes' high level of reliability. The proposed segmentation algorithm provided 96.89% overall correctness, 95.84% completeness, a 0.25 m overall mean value of centroid difference, and less than 1° of angle difference. The performance of the proposed approach was also verified with a large dataset and compared with other approaches. Additionally, the evaluation of the sensitivity of the thresholds was carried out. In summary, this paper proposes a robust and efficient segmentation methodology for abstraction of an enormous number of laser points into plane information. PMID:26805849

  16. Method to quantify accuracy of position feedback signals of a three-dimensional two-photon laser-scanning microscope

    PubMed Central

    Kummer, Michael; Kirmse, Knut; Witte, Otto W.; Haueisen, Jens; Holthoff, Knut

    2015-01-01

    Two-photon laser-scanning microscopy enables to record neuronal network activity in three-dimensional space while maintaining single-cellular resolution. One of the proposed approaches combines galvanometric x-y scanning with piezo-driven objective movements and employs hardware feedback signals for position monitoring. However, readily applicable methods to quantify the accuracy of those feedback signals are currently lacking. Here we provide techniques based on contact-free laser reflection and laser triangulation for the quantification of positioning accuracy of each spatial axis. We found that the lateral feedback signals are sufficiently accurate (defined as <2.5 µm) for a wide range of scan trajectories and frequencies. We further show that axial positioning accuracy does not only depend on objective acceleration and mass but also its geometry. We conclude that the introduced methods allow a reliable quantification of position feedback signals in a cost-efficient, easy-to-install manner and should be applicable for a wide range of two-photon laser scanning microscopes. PMID:26504620

  17. Method to quantify accuracy of position feedback signals of a three-dimensional two-photon laser-scanning microscope.

    PubMed

    Kummer, Michael; Kirmse, Knut; Witte, Otto W; Haueisen, Jens; Holthoff, Knut

    2015-10-01

    Two-photon laser-scanning microscopy enables to record neuronal network activity in three-dimensional space while maintaining single-cellular resolution. One of the proposed approaches combines galvanometric x-y scanning with piezo-driven objective movements and employs hardware feedback signals for position monitoring. However, readily applicable methods to quantify the accuracy of those feedback signals are currently lacking. Here we provide techniques based on contact-free laser reflection and laser triangulation for the quantification of positioning accuracy of each spatial axis. We found that the lateral feedback signals are sufficiently accurate (defined as <2.5 µm) for a wide range of scan trajectories and frequencies. We further show that axial positioning accuracy does not only depend on objective acceleration and mass but also its geometry. We conclude that the introduced methods allow a reliable quantification of position feedback signals in a cost-efficient, easy-to-install manner and should be applicable for a wide range of two-photon laser scanning microscopes. PMID:26504620

  18. Merging Terrestrial Laser Scanning Technology with Photogrammetric and Total Station Data for the Determination of Avalanche Modeling Parameters

    NASA Astrophysics Data System (ADS)

    Prokop, Alexander; Schön, Peter; Singer, Florian; Pulfer, Gaëtan; Naaim, Mohamed; Thibert, Emmanuel

    2015-04-01

    Dynamic avalanche modeling requires as input the volumes and areas of the snow released, entrained and deposited, as well as the fracture heights. Determining these parameters requires high-resolution spatial snow surface data from before and after the avalanche. In snow and avalanche research, terrestrial laser scanners are used increasingly to efficiently and accurately map snow surfaces and depths over an area of several km². In practice however, several problems may occur, which must be recognized and accounted for during post-processing and interpretation, especially under the circumstances of surveying an artificially triggered avalanche at a test site, where time pressure due to operational time constraints may also cause less than ideal circumstances and surveying setups. Thus, we combine terrestrial laser scanning with photogrammetry, total station measurements and field snow observations to document and accurately survey an artificially triggered avalanche at the Col du Lautaret test site (2058 m) in the French Alps. The ability of TLS to determine avalanche modeling input parameters efficiently and accurately is shown, and we demonstrate how, merging TLS with the other methods facilitates and improves data post-processing and interpretation. Finally, we present for this avalanche the data required for the parameterization and validation of dynamic avalanche models and discuss using newest data, how the new laser scanning device generation (e.g Riegl VZ6000) further improves such surveying campaigns.

  19. Density of point clouds in mobile laser scanning. (Polish Title: Gestosc chmury punktow pochodzacej z mobilnego skanowania laserowego)

    NASA Astrophysics Data System (ADS)

    Warchoł, A.

    2015-12-01

    The LiDAR (Light Detection And Ranging) technology is becoming a more and more popular method to collect spatial information. The acquisition of 3D data by means of one or several laser scanners mounted on a mobile platform (car) could quickly provide large volumes of dense data with centimeter-level accuracy. This is, therefore, the ideal solution to obtain information about objects with elongated shapes (corridors), and their surroundings. Point clouds used by specific applications must fulfill certain quality criteria, such as quantitative and qualitative indicators (i.e. precision, accuracy, density, completeness).Usually, the client fixes some parameter values that must be achieved. In terms of the precision, this parameter is well described, whereas in the case of density point clouds the discussion is still open. Due to the specificities of the MLS (Mobile Laser Scanning), the solution from ALS (Airborne Laser Scanning) cannot be directly applied. Hence, the density of the final point clouds, calculated as the number of points divided by "flat" surface area, is inappropriate. We present in this article three different ways of determining and interpreting point cloud density on three different test fields. The first method divides the number of points by the "flat" area, the second by the "three-dimensional" area, and the last one refers to a voxel approach. The most reliable method seems to be the voxel method, which in addition to the local density values also presents their spatial distribution.

  20. Terrestrial laser scanning and a degenerated cylinder model to determine gross morphological change of cadavers under conditions of natural decomposition.

    PubMed

    Zhang, Xiao; Glennie, Craig L; Bucheli, Sibyl R; Lindgren, Natalie K; Lynne, Aaron M

    2014-08-01

    Decomposition can be a highly variable process with stages that are difficult to quantify. Using high accuracy terrestrial laser scanning a repeated three-dimensional (3D) documentation of volumetric changes of a human body during early decomposition is recorded. To determine temporal volumetric variations as well as 3D distribution of the changed locations in the body over time, this paper introduces the use of multiple degenerated cylinder models to provide a reasonable approximation of body parts against which 3D change can be measured and visualized. An iterative closest point algorithm is used for 3D registration, and a method for determining volumetric change is presented. Comparison of the laser scanning estimates of volumetric change shows good agreement with repeated in-situ measurements of abdomen and limb circumference that were taken diurnally. The 3D visualizations of volumetric changes demonstrate that bloat is a process with a beginning, middle, and end rather than a state of presence or absence. Additionally, the 3D visualizations show conclusively that cadaver bloat is not isolated to the abdominal cavity, but also occurs in the limbs. Detailed quantification of the bloat stage of decay has the potential to alter how the beginning and end of bloat are determined by researchers and can provide further insight into the effects of the ecosystem on decomposition. PMID:24866865

  1. A setup for combined multiphoton laser scanning microscopic and multi-electrode patch clamp experiments on brain slices

    NASA Astrophysics Data System (ADS)

    Helm, P. Johannes; Reppen, Trond; Heggelund, Paul

    2009-02-01

    Multi Photon Laser Scanning Microscopy (MPLSM) appears today as one of the most powerful experimental tools in cellular neurophysiology, notably in studies of the functional dynamics of signal processing in single neurons. Simultaneous recording of fluorescence signals at high spatial and temporal resolution and electric signals by means of multi electrode patch clamp techniques have provided new paths for the systematic investigation of neuronal mechanisms. In particular, this approach has opened for direct studies of dendritic signal processing in neurons. We report about a setup optimized for simultaneous electrophysiological multi electrode patch clamp and multi photon laser scanning fluorescence microscopic experiments on brain slices. The microscopic system is based on a modified commercially available confocal scanning laser microscope (CLSM). From a technical and operational point of view, two developments are important: Firstly, in order to reduce the workload for the experimentalist, who in general is forced to concentrate on controlling the electrophysiological parameters during the recordings, a system of shutters has been installed together with dedicated electronic modules protecting the photo detectors against destructive light levels caused by erroneous opening or closing of microscopic light paths by the experimentalist. Secondly, the standard detection unit has been improved by installing the photomultiplier tubes (PMT) in a Peltier cooled thermal box shielding the detector from both room temperature and distortions caused by external electromagnetic fields. The electrophysiological system is based on an industrial standard multi patch clamp unit ergonomically arranged around the microscope stage. The electrophysiological and scanning processes can be time coordinated by standard trigger electronics.

  2. Recent rock fall activity in the Wetterstein Mountains revealed by a time series of terrestrial laser scans

    NASA Astrophysics Data System (ADS)

    Schöpa, Anne; Baewert, Henning; Cook, Kristen; Morche, David

    2015-04-01

    The north face of the Hochwanner in the Reintal valley, Wetterstein Mountains, southern Germany, has been a site of frequent rock fall activity for the past several hundred years. The so-called 'Steingerümpel' rock fall included an estimated volume of 2.3-2.7 x 106 m3 and led to damming of the Partnach river. This event was dated to 1400-1600 AD. The rock fall left a prominent scar in the rock face where subsequent rock fall activity was concentrated, postulated to be a 'delayed consequence' of the Steingerümpel event. Previous workers used airborne and terrestrial laser scan data to evaluate the volume of the detached material and the deposits on the talus cone at the foot of the slope from the 'delayed consequence' activity between 2006 and 2008 (Heckmann et al., 2012). The largest event during this period was a 5 x 104 m3 rock fall in August 2007. We compared the data of six terrestrial laser scans, which were acquired in June and September 2008, September 2010, June 2011, August 2013, October and November 2014, in order to assess the volumes of detached material after the large rock fall event of 2007. The aim is to investigate the post-event activity at a site of a large rock fall in order to give estimates about the timing when the activity is back to normal conditions in relation to the magnitude of the large event. Although no large rock fall occurred in the observation period, the comparison of the laser scan data indicate that the average rock wall retreat at this site is still higher compared to the mean annual rock wall retreat rate of 0.54 mm/yr for the last millennium in the Reintal valley (Krautblatter et al., 2012). This shows that sites of large rock falls remain active even years after the event. Heckmann, T.; Bimböse, M.; Krautblatter, M.; Haas, F.; Becht, M.; Morche, D. (2012): From geotechnical analysis to quantification and modelling using LiDAR data: a study on rockfall in the Reintal catchment, Bavarian Alps, Germany; Earth Surface

  3. NAVIS-An UGV Indoor Positioning System Using Laser Scan Matching for Large-Area Real-Time Applications

    PubMed Central

    Tang, Jian.; Chen, Yuwei.; Jaakkola, Anttoni.; Liu, Jinbing.; Hyyppä, Juha.; Hyyppä, Hannu.

    2014-01-01

    Laser scan matching with grid-based maps is a promising tool for real-time indoor positioning of mobile Unmanned Ground Vehicles (UGVs). While there are critical implementation problems, such as the ability to estimate the position by sensing the unknown indoor environment with sufficient accuracy and low enough latency for stable vehicle control, further development work is necessary. Unfortunately, most of the existing methods employ heuristics for quick positioning in which numerous accumulated errors easily lead to loss of positioning accuracy. This severely restricts its applications in large areas and over lengthy periods of time. This paper introduces an efficient real-time mobile UGV indoor positioning system for large-area applications using laser scan matching with an improved probabilistically-motivated Maximum Likelihood Estimation (IMLE) algorithm, which is based on a multi-resolution patch-divided grid likelihood map. Compared with traditional methods, the improvements embodied in IMLE include: (a) Iterative Closed Point (ICP) preprocessing, which adaptively decreases the search scope; (b) a totally brute search matching method on multi-resolution map layers, based on the likelihood value between current laser scan and the grid map within refined search scope, adopted to obtain the global optimum position at each scan matching; and (c) a patch-divided likelihood map supporting a large indoor area. A UGV platform called NAVIS was designed, manufactured, and tested based on a low-cost robot integrating a LiDAR and an odometer sensor to verify the IMLE algorithm. A series of experiments based on simulated data and field tests with NAVIS proved that the proposed IMEL algorithm is a better way to perform local scan matching that can offer a quick and stable positioning solution with high accuracy so it can be part of a large area localization/mapping, application. The NAVIS platform can reach an updating rate of 12 Hz in a feature-rich environment and 2 Hz

  4. NAVIS-An UGV indoor positioning system using laser scan matching for large-area real-time applications.

    PubMed

    Tang, Jian; Chen, Yuwei; Jaakkola, Anttoni; Liu, Jinbing; Hyyppä, Juha; Hyyppä, Hannu

    2014-01-01

    Laser scan matching with grid-based maps is a promising tool for real-time indoor positioning of mobile Unmanned Ground Vehicles (UGVs). While there are critical implementation problems, such as the ability to estimate the position by sensing the unknown indoor environment with sufficient accuracy and low enough latency for stable vehicle control, further development work is necessary. Unfortunately, most of the existing methods employ heuristics for quick positioning in which numerous accumulated errors easily lead to loss of positioning accuracy. This severely restricts its applications in large areas and over lengthy periods of time. This paper introduces an efficient real-time mobile UGV indoor positioning system for large-area applications using laser scan matching with an improved probabilistically-motivated Maximum Likelihood Estimation (IMLE) algorithm, which is based on a multi-resolution patch-divided grid likelihood map. Compared with traditional methods, the improvements embodied in IMLE include: (a) Iterative Closed Point (ICP) preprocessing, which adaptively decreases the search scope; (b) a totally brute search matching method on multi-resolution map layers, based on the likelihood value between current laser scan and the grid map within refined search scope, adopted to obtain the global optimum position at each scan matching; and (c) a patch-divided likelihood map supporting a large indoor area. A UGV platform called NAVIS was designed, manufactured, and tested based on a low-cost robot integrating a LiDAR and an odometer sensor to verify the IMLE algorithm. A series of experiments based on simulated data and field tests with NAVIS proved that the proposed IMEL algorithm is a better way to perform local scan matching that can offer a quick and stable positioning solution with high accuracy so it can be part of a large area localization/mapping, application. The NAVIS platform can reach an updating rate of 12 Hz in a feature-rich environment and 2 Hz

  5. Mapping tree health using airborne full-waveform laser scans and hyperspectral imagery: a case study for floodplain eucalypt forest

    NASA Astrophysics Data System (ADS)

    Shendryk, I.; Tulbure, M. G.; Broich, M.

    2014-12-01

    Barmah-Millewa Forest (BMF), the largest River Red Gum forest in the world, located in south-eastern Australia is suffering from severe dieback, thus diminishing its ecological and economical value. Previous research showed that dieback is a good predictor of the forest health and stressed the need for BMF health mapping and change monitoring. In this respect, airborne laser scanning and hyperspectral imaging offer extensive spatial and spectral coverage of measurements and represent an ideal tool for forest health mapping at individual tree scale. The aim of this project is to quantify the health of individual, structurally complex floodplain eucalypt trees by integrating airborne hyperspectral imagery, full-waveform laser scans and field measurements. An aerial survey, conducted in May 2014, was designed to provide a representative sample of BMF tree health. The positioning of 17 flight lines aimed to capture the heterogeneity of the forest health and flood frequency. Preliminary analysis of the aerial remote sensing data with regards to chlorophyll concentrations, dieback levels and canopy densities allowed us to target our field campaign (conducted in June 2014). Field measurements included accurate position measurements, LAI, visual assessment, spectral measurement and mensuration of individual trees in 30 m2 plots. For detection of individual tree trunks from airborne laser scans we used a novel approach based on Euclidean distance clustering, taking advantage of the intensity and pulse width difference between woody and leaf tree compartments. The detected trunks were used to seed a minimum cut algorithm for tree crown delineation. In situ measurements confirmed the high structural diversity of the forest and allowed the calibration of the tree detection algorithm. An overall accuracy of the tree detection of 54% and 67% was achieved for trees with circumference over 40 cm and over 100 cm respectively. As a further step, 3D point clusters representing

  6. Application of terrestrial laser scanning for detection of ground surface deformation in small mud volcano (Murono, Japan)

    NASA Astrophysics Data System (ADS)

    Hayakawa, Yuichi S.; Kusumoto, Shigekazu; Matta, Nobuhisa

    2016-07-01

    We perform terrestrial laser scanning (TLS) to detect changes in surface morphology of a mud volcano in Murono, north-central Japan. The study site underwent significant deformation by a strong earthquake in 2011, and the surface deformation has continued in the following years. The point cloud datasets were obtained by TLS at three different times in 2011, 2013 and 2014. Those point clouds were aligned by cloud-based registration, which minimizes the closest point distance of point clouds of unchanged ground features, and the TLS-based point cloud data appear to be suitable for detecting centimeter-order deformations in the central domain of the mud volcano, as well as for measurements of topographic features including cracks of paved ground surface. The spatial patterns and accumulative amount of the vertical deformation during 2011-2014 captured by TLS correspond well with those previously reported based on point-based leveling surveys, supporting the validity of TLS survey.

  7. Real-time mapping of the corneal sub-basal nerve plexus by in vivo laser scanning confocal microscopy

    NASA Astrophysics Data System (ADS)

    Guthoff, Rudolf F.; Zhivov, Andrey; Stachs, Oliver

    2010-02-01

    The aim of the study was to produce two-dimensional reconstruction maps of the living corneal sub-basal nerve plexus by in vivo laser scanning confocal microscopy in real time. CLSM source data (frame rate 30Hz, 384x384 pixel) were used to create large-scale maps of the scanned area by selecting the Automatic Real Time (ART) composite mode. The mapping algorithm is based on an affine transformation. Microscopy of the sub-basal nerve plexus was performed on normal and LASIK eyes as well as on rabbit eyes. Real-time mapping of the sub-basal nerve plexus was performed in large-scale up to a size of 3.2mm x 3.2mm. The developed method enables a real-time in vivo mapping of the sub-basal nerve plexus which is stringently necessary for statistically firmed conclusions about morphometric plexus alterations.

  8. Integration of Point Clouds from Terrestrial Laser Scanning and Image-Based Matching for Generating High-Resolution Orthoimages

    NASA Astrophysics Data System (ADS)

    Salach, A.; Markiewicza, J. S.; Zawieska, D.

    2016-06-01

    An orthoimage is one of the basic photogrammetric products used for architectural documentation of historical objects; recently, it has become a standard in such work. Considering the increasing popularity of photogrammetric techniques applied in the cultural heritage domain, this research examines the two most popular measuring technologies: terrestrial laser scanning, and automatic processing of digital photographs. The basic objective of the performed works presented in this paper was to optimize the quality of generated high-resolution orthoimages using integration of data acquired by a Z+F 5006 terrestrial laser scanner and a Canon EOS 5D Mark II digital camera. The subject was one of the walls of the "Blue Chamber" of the Museum of King Jan III's Palace at Wilanów (Warsaw, Poland). The high-resolution images resulting from integration of the point clouds acquired by the different methods were analysed in detail with respect to geometric and radiometric correctness.

  9. Remote z-scanning with a macroscopic voice coil motor for fast 3D multiphoton laser scanning microscopy

    PubMed Central

    Rupprecht, Peter; Prendergast, Andrew; Wyart, Claire; Friedrich, Rainer W

    2016-01-01

    There is a high demand for 3D multiphoton imaging in neuroscience and other fields but scanning in axial direction presents technical challenges. We developed a focusing technique based on a remote movable mirror that is conjugate to the specimen plane and translated by a voice coil motor. We constructed cost-effective z-scanning modules from off-the-shelf components that can be mounted onto standard multiphoton laser scanning microscopes to extend scan patterns from 2D to 3D. Systems were designed for large objectives and provide high resolution, high speed and a large z-scan range (>300 μm). We used these systems for 3D multiphoton calcium imaging in the adult zebrafish brain and measured odor-evoked activity patterns across >1500 neurons with single-neuron resolution and high signal-to-noise ratio. PMID:27231612

  10. Capturing Detailed Outcrop Geology Using Terrestrial Laser Scanning (Lidar) and Other Digital Technologies: Current Status and Future Directions

    NASA Astrophysics Data System (ADS)

    Jones, R. R.; McCaffrey, K. J.

    2007-12-01

    Geospatial data acquisition at global to regional scales has wide acceptance, and tools such as Google Earth have been instrumental in extending Earth visualisation far beyond specialist users of GIS and satellite imagery. At the outcrop scale, the number of industry and academic geoscientists adopting digital technologies to gather field data is steadily increasing. When integrated with traditional field skills, these technologies offer two fundamental advantages: firstly, outcrop geology can now be recorded with very high detail and precision; secondly, observations and data are precisely georeferenced, which is a prerequisite for 2D and 3D spatial analysis. Digital outcrop data are being used in a wide variety of ways, many of which can be characterised in terms of two end members. Firstly, using methods such as terrestrial laser scanning and digital photogrammetry, it is possible to create highly realistic virtual copies of the outcrop. These virtual outcrop models can be used to great effect to enhance teaching, to provide virtual field-trips (most effective in conjunction with a real visit to the outcrop), to promote group discussion and interpretation, or as part of Health & Safety briefing. Secondly, digital outcrop data is also being used to derive quantitative attribute measurements from specific geological features. Here the emphasis is not on capturing a photo-realistic copy of the outcrop, but rather on gathering the relevant types of data at the most appropriate resolution and geospatial precision for the type of analysis undertaken. In addition to laser scanning, useful technologies include dGPS, laser range-finding, and Total Station surveying. Examples of this kind of quantitative analysis include fault curvature, roughness, branch-line geometry, spatial variation in fault displacement, fracture spacing and 3D spatial clustering, fold curvature, sedimentary channel morphology, lateral and vertical facies variations, and geomorphological analysis of

  11. The Functional Organization of Neocortical Networks Investigated in Slices with Local Field Recordings and Laser Scanning Photostimulation

    PubMed Central

    Erlandson, Melissa A.; Manzoni, Olivier J.; Bureau, Ingrid

    2015-01-01

    The organization of cortical networks can be investigated functionally in brain slices. Laser scanning photostimulation (LSPS) with glutamate-uncaging allows for a rapid survey of all connections impinging on single cells recorded in patch-clamp. We sought to develop a variant of the method that would allow for a more exhaustive mapping of neuronal networks at every experiment. We found that the extracellular field recordings could be used to detect synaptic responses evoked by LSPS. One to two electrodes were placed in all six cortical layers of barrel cortex successively and maps were computed from the size of synaptic negative local field potentials. The field maps displayed a laminar organization similar to the one observed in maps computed from excitatory postsynaptic currents recorded in patch-clamp mode. Thus, LSPS combined with field recording is an interesting alternative to obtain for every animal tested a comprehensive map of the excitatory intracortical network. PMID:26134668

  12. Analysis of the penetration of a caffeine containing shampoo into the hair follicles by in vivo laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Lademann, J.; Richter, H.; Schanzer, S.; Klenk, A.; Sterry, W.; Patzelt, A.

    2010-02-01

    In previous in vitro investigations, it was demonstrated that caffeine is able to stimulate the hair growth. Therefore, a penetration of caffeine into the hair follicle is necessary. In the present study, in vivo laser scanning microscopy (LSM) was used to investigate the penetration and storage of a caffeine containing shampoo into the hair follicles. It was shown that a 2-min contact time of the shampoo with the skin was enough to accumulate significant parts of the shampoo in the hair follicles. A penetration of the shampoo up to a depth of approx. 200 μm could be detected, which represents the detection limit of the LSM. At this depth, the close network of the blood capillaries surrounding the hair follicles commences. Even after 24 h, the substance was still detectable in the hair follicles. This demonstrates the long-term reservoir function of the hair follicles for topically applied substances such as caffeine.

  13. The double K+/Ca2+ sensor based on laser scanned silicon transducer (LSST) for multi-component analysis.

    PubMed

    Ermolenko, Yu; Yoshinobu, T; Mourzina, Yu; Furuichi, K; Levichev, S; Schöning, M J; Vlasov, Yu; Iwasaki, H

    2003-03-10

    In the present work a double ion sensor based on a laser scanned semiconductor transducer (LSST) for the simultaneous determination of K(+)- and Ca(2+)-ions in solutions has been developed. Specially elaborated ion-sensitive membrane compositions based on valinomycin and calcium ionophore calcium bis[4-(1,1,3,3-tetramethylbutyl)phenyl] phosphate (t-HDOPP-Ca) were deposited as separate layers on a silanized surface of the Si/SiO(2)/Si(3)N(4)-transducer. The proposed multi-sensor exhibits theoretical sensitivities and the detection limits of the sensor were found to be 2 x 10(-6) mol l(-1) for K(+) and 5 x 10(-6) mol l(-1) for Ca(2+). The elaborated double sensor is proposed for the first time as a prototype of a new type of multi-sensor systems for chemical analysis. PMID:18968966

  14. Remote z-scanning with a macroscopic voice coil motor for fast 3D multiphoton laser scanning microscopy.

    PubMed

    Rupprecht, Peter; Prendergast, Andrew; Wyart, Claire; Friedrich, Rainer W

    2016-05-01

    There is a high demand for 3D multiphoton imaging in neuroscience and other fields but scanning in axial direction presents technical challenges. We developed a focusing technique based on a remote movable mirror that is conjugate to the specimen plane and translated by a voice coil motor. We constructed cost-effective z-scanning modules from off-the-shelf components that can be mounted onto standard multiphoton laser scanning microscopes to extend scan patterns from 2D to 3D. Systems were designed for large objectives and provide high resolution, high speed and a large z-scan range (>300 μm). We used these systems for 3D multiphoton calcium imaging in the adult zebrafish brain and measured odor-evoked activity patterns across >1500 neurons with single-neuron resolution and high signal-to-noise ratio. PMID:27231612