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Sample records for 3d object retrieval

  1. 3D object retrieval using salient views

    PubMed Central

    Shapiro, Linda G.

    2013-01-01

    This paper presents a method for selecting salient 2D views to describe 3D objects for the purpose of retrieval. The views are obtained by first identifying salient points via a learning approach that uses shape characteristics of the 3D points (Atmosukarto and Shapiro in International workshop on structural, syntactic, and statistical pattern recognition, 2008; Atmosukarto and Shapiro in ACM multimedia information retrieval, 2008). The salient views are selected by choosing views with multiple salient points on the silhouette of the object. Silhouette-based similarity measures from Chen et al. (Comput Graph Forum 22(3):223–232, 2003) are then used to calculate the similarity between two 3D objects. Retrieval experiments were performed on three datasets: the Heads dataset, the SHREC2008 dataset, and the Princeton dataset. Experimental results show that the retrieval results using the salient views are comparable to the existing light field descriptor method (Chen et al. in Comput Graph Forum 22(3):223–232, 2003), and our method achieves a 15-fold speedup in the feature extraction computation time. PMID:23833704

  2. 3D object retrieval using salient views.

    PubMed

    Atmosukarto, Indriyati; Shapiro, Linda G

    2013-06-01

    This paper presents a method for selecting salient 2D views to describe 3D objects for the purpose of retrieval. The views are obtained by first identifying salient points via a learning approach that uses shape characteristics of the 3D points (Atmosukarto and Shapiro in International workshop on structural, syntactic, and statistical pattern recognition, 2008; Atmosukarto and Shapiro in ACM multimedia information retrieval, 2008). The salient views are selected by choosing views with multiple salient points on the silhouette of the object. Silhouette-based similarity measures from Chen et al. (Comput Graph Forum 22(3):223-232, 2003) are then used to calculate the similarity between two 3D objects. Retrieval experiments were performed on three datasets: the Heads dataset, the SHREC2008 dataset, and the Princeton dataset. Experimental results show that the retrieval results using the salient views are comparable to the existing light field descriptor method (Chen et al. in Comput Graph Forum 22(3):223-232, 2003), and our method achieves a 15-fold speedup in the feature extraction computation time. PMID:23833704

  3. Intraclass retrieval of nonrigid 3D objects: application to face recognition.

    PubMed

    Passalis, Georgios; Kakadiaris, Ioannis A; Theoharis, Theoharis

    2007-02-01

    As the size of the available collections of 3D objects grows, database transactions become essential for their management with the key operation being retrieval (query). Large collections are also precategorized into classes so that a single class contains objects of the same type (e.g., human faces, cars, four-legged animals). It is shown that general object retrieval methods are inadequate for intraclass retrieval tasks. We advocate that such intraclass problems require a specialized method that can exploit the basic class characteristics in order to achieve higher accuracy. A novel 3D object retrieval method is presented which uses a parameterized annotated model of the shape of the class objects, incorporating its main characteristics. The annotated subdivision-based model is fitted onto objects of the class using a deformable model framework, converted to a geometry image and transformed into the wavelet domain. Object retrieval takes place in the wavelet domain. The method does not require user interaction, achieves high accuracy, is efficient for use with large databases, and is suitable for nonrigid object classes. We apply our method to the face recognition domain, one of the most challenging intraclass retrieval tasks. We used the Face Recognition Grand Challenge v2 database, yielding an average verification rate of 95.2 percent at 10-3 false accept rate. The latest results of our work can be found at http://www.cbl.uh.edu/UR8D/. PMID:17170476

  4. Perception-based shape retrieval for 3D building models

    NASA Astrophysics Data System (ADS)

    Zhang, Man; Zhang, Liqiang; Takis Mathiopoulos, P.; Ding, Yusi; Wang, Hao

    2013-01-01

    With the help of 3D search engines, a large number of 3D building models can be retrieved freely online. A serious disadvantage of most rotation-insensitive shape descriptors is their inability to distinguish between two 3D building models which are different at their main axes, but appear similar when one of them is rotated. To resolve this problem, we present a novel upright-based normalization method which not only correctly rotates such building models, but also greatly simplifies and accelerates the abstraction and the matching of building models' shape descriptors. Moreover, the abundance of architectural styles significantly hinders the effective shape retrieval of building models. Our research has shown that buildings with different designs are not well distinguished by the widely recognized shape descriptors for general 3D models. Motivated by this observation and to further improve the shape retrieval quality, a new building matching method is introduced and analyzed based on concepts found in the field of perception theory and the well-known Light Field descriptor. The resulting normalized building models are first classified using the qualitative shape descriptors of Shell and Unevenness which outline integral geometrical and topological information. These models are then put in on orderly fashion with the help of an improved quantitative shape descriptor which we will term as Horizontal Light Field Descriptor, since it assembles detailed shape characteristics. To accurately evaluate the proposed methodology, an enlarged building shape database which extends previous well-known shape benchmarks was implemented as well as a model retrieval system supporting inputs from 2D sketches and 3D models. Various experimental performance evaluation results have shown that, as compared to previous methods, retrievals employing the proposed matching methodology are faster and more consistent with human recognition of spatial objects. In addition these performance

  5. New method of 3-D object recognition

    NASA Astrophysics Data System (ADS)

    He, An-Zhi; Li, Qun Z.; Miao, Peng C.

    1991-12-01

    In this paper, a new method of 3-D object recognition using optical techniques and a computer is presented. We perform 3-D object recognition using moire contour to obtain the object's 3- D coordinates, projecting drawings of the object in three coordinate planes to describe it and using a method of inquiring library of judgement to match objects. The recognition of a simple geometrical entity is simulated by computer and studied experimentally. The recognition of an object which is composed of a few simple geometrical entities is discussed.

  6. Lifting Object Detection Datasets into 3D.

    PubMed

    Carreira, Joao; Vicente, Sara; Agapito, Lourdes; Batista, Jorge

    2016-07-01

    While data has certainly taken the center stage in computer vision in recent years, it can still be difficult to obtain in certain scenarios. In particular, acquiring ground truth 3D shapes of objects pictured in 2D images remains a challenging feat and this has hampered progress in recognition-based object reconstruction from a single image. Here we propose to bypass previous solutions such as 3D scanning or manual design, that scale poorly, and instead populate object category detection datasets semi-automatically with dense, per-object 3D reconstructions, bootstrapped from:(i) class labels, (ii) ground truth figure-ground segmentations and (iii) a small set of keypoint annotations. Our proposed algorithm first estimates camera viewpoint using rigid structure-from-motion and then reconstructs object shapes by optimizing over visual hull proposals guided by loose within-class shape similarity assumptions. The visual hull sampling process attempts to intersect an object's projection cone with the cones of minimal subsets of other similar objects among those pictured from certain vantage points. We show that our method is able to produce convincing per-object 3D reconstructions and to accurately estimate cameras viewpoints on one of the most challenging existing object-category detection datasets, PASCAL VOC. We hope that our results will re-stimulate interest on joint object recognition and 3D reconstruction from a single image. PMID:27295458

  7. 3D modeling of optically challenging objects.

    PubMed

    Park, Johnny; Kak, Avinash

    2008-01-01

    We present a system for constructing 3D models of real-world objects with optically challenging surfaces. The system utilizes a new range imaging concept called multi-peak range imaging, which stores multiple candidates of range measurements for each point on the object surface. The multiple measurements include the erroneous range data caused by various surface properties that are not ideal for structured-light range sensing. False measurements generated by spurious reflections are eliminated by applying a series of constraint tests. The constraint tests based on local surface and local sensor visibility are applied first to individual range images. The constraint tests based on global consistency of coordinates and visibility are then applied to all range images acquired from different viewpoints. We show the effectiveness of our method by constructing 3D models of five different optically challenging objects. To evaluate the performance of the constraint tests and to examine the effects of the parameters used in the constraint tests, we acquired the ground truth data by painting those objects to suppress the surface-related properties that cause difficulties in range sensing. Experimental results indicate that our method significantly improves upon the traditional methods for constructing reliable 3D models of optically challenging objects. PMID:18192707

  8. 3-D object-oriented image analysis of geophysical data

    NASA Astrophysics Data System (ADS)

    Fadel, I.; Kerle, N.; van der Meijde, M.

    2014-07-01

    Geophysical data are the main source of information about the subsurface. Geophysical techniques are, however, highly non-unique in determining specific physical parameters and boundaries of subsurface objects. To obtain actual physical information, an inversion process is often applied, in which measurements at or above the Earth surface are inverted into a 2- or 3-D subsurface spatial distribution of the physical property. Interpreting these models into structural objects, related to physical processes, requires a priori knowledge and expert analysis which is susceptible to subjective choices and is therefore often non-repeatable. In this research, we implemented a recently introduced object-based approach to interpret the 3-D inversion results of a single geophysical technique using the available a priori information and the physical and geometrical characteristics of the interpreted objects. The introduced methodology is semi-automatic and repeatable, and allows the extraction of subsurface structures using 3-D object-oriented image analysis (3-D OOA) in an objective knowledge-based classification scheme. The approach allows for a semi-objective setting of thresholds that can be tested and, if necessary, changed in a very fast and efficient way. These changes require only changing the thresholds used in a so-called ruleset, which is composed of algorithms that extract objects from a 3-D data cube. The approach is tested on a synthetic model, which is based on a priori knowledge on objects present in the study area (Tanzania). Object characteristics and thresholds were well defined in a 3-D histogram of velocity versus depth, and objects were fully retrieved. The real model results showed how 3-D OOA can deal with realistic 3-D subsurface conditions in which the boundaries become fuzzy, the object extensions become unclear and the model characteristics vary with depth due to the different physical conditions. As expected, the 3-D histogram of the real data was

  9. Faint object 3D spectroscopy with PMAS

    NASA Astrophysics Data System (ADS)

    Roth, Martin M.; Becker, Thomas; Kelz, Andreas; Bohm, Petra

    2004-09-01

    PMAS is a fiber-coupled lens array type of integral field spectrograph, which was commissioned at the Calar Alto 3.5m Telescope in May 2001. The optical layout of the instrument was chosen such as to provide a large wavelength coverage, and good transmission from 0.35 to 1 μm. One of the major objectives of the PMAS development has been to perform 3D spectrophotometry, taking advantage of the contiguous array of spatial elements over the 2-dimensional field-of-view of the integral field unit. With science results obtained during the first two years of operation, we illustrate that 3D spectroscopy is an ideal tool for faint object spectrophotometry.

  10. Improved differential 3D shape retrieval

    NASA Astrophysics Data System (ADS)

    Liu, Tongchuan; Zhou, Canlin; Si, Shuchun; Li, Hui; Lei, Zhenkun

    2015-10-01

    Phase unwrapping is a complex step in three-dimensional (3D) surface measurement. To simplify the computation process, Martino et al. proposed a differential algorithm. However, it will result in large error when the orthogonal fringes are not in horizontal or vertical direction. To solve this problem, the relationship between projector's and camera's coordinate systems is introduced. With the data obtained from coordinate transformation, the improved differential algorithm can be used for orthogonal fringes in any direction. Besides that, taking advantage of Fourier differentiation theorem makes operation and calculation simpler. By contrast, the results of experiments show that the proposed method is applicable to the patterns with orthogonal fringes in every direction. In addition, Fourier differentiation theorem effectively increases the speed of differential process.

  11. PMAS - Faint Object 3D Spectrophotometry

    NASA Astrophysics Data System (ADS)

    Roth, M. M.; Becker, T.; Kelz, A.

    2002-01-01

    will describe PMAS (Potsdam Multiaperture Spectrophotometer) which was commissioned at the Calar Alto Observatory 3.5m Telescope on May 28-31, 2001. PMAS is a dedicated, highly efficient UV-visual integral field spectrograph which is optimized for the spectrophotometry of faint point sources, typically superimposed on a bright background. PMAS is ideally suited for the study of resolved stars in local group galaxies. I will present results of our preliminary work with MPFS at the Russian 6m Telescope in Selentchuk, involving the development of new 3D data reduction software, and observations of faint planetary nebulae in the bulge of M31 for the determination of individual chemical abundances of these objects. Using this data, it will be demonstrated that integral field spectroscopy provides superior techniques for background subtraction, avoiding the otherwise inevitable systematic errors of conventional slit spetroscopy. The results will be put in perspective of the study of resolved stellar populations in nearby galaxies with a new generation of Extremely Large Telescopes.

  12. Visual inertia of rotating 3-D objects.

    PubMed

    Jiang, Y; Pantle, A J; Mark, L S

    1998-02-01

    Five experiments were designed to determine whether a rotating, transparent 3-D cloud of dots (simulated sphere) could influence the perceived direction of rotation of a subsequent sphere. Experiment 1 established conditions under which the direction of rotation of a virtual sphere was perceived unambiguously. When a near-far luminance difference and perspective depth cues were present, observers consistently saw the sphere rotate in the intended direction. In Experiment 2, a near-far luminance difference was used to create an unambiguous rotation sequence that was followed by a directionally ambiguous rotation sequence that lacked both the near-far luminance cue and the perspective cue. Observers consistently saw the second sequence as rotating in the same direction as the first, indicating the presence of 3-D visual inertia. Experiment 3 showed that 3-D visual inertia was sufficiently powerful to bias the perceived direction of a rotation sequence made unambiguous by a near-far luminance cue. Experiment 5 showed that 3-D visual inertia could be obtained using an occlusion depth cue to create an unambiguous inertia-inducing sequence. Finally, Experiments 2, 4, and 5 all revealed a fast-decay phase of inertia that lasted for approximately 800 msec, followed by an asymptotic phase that lasted for periods as long as 1,600 msec. The implications of these findings are examined with respect to motion mechanisms of 3-D visual inertia. PMID:9529911

  13. Cloud Property Retrieval and 3D Radiative Transfer

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert F.

    2003-01-01

    Cloud thickness and photon mean-free-path together determine the scale of "radiative smoothing" of cloud fluxes and radiances. This scale is observed as a change in the spatial spectrum of cloud radiances, and also as the "halo size" seen by off beam lidar such as THOR and WAIL. Such of beam lidar returns are now being used to retrieve cloud layer thickness and vertical scattering extinction profile. We illustrate with recent measurements taken at the Oklahoma ARM site, comparing these to the-dependent 3D simulations. These and other measurements sensitive to 3D transfer in clouds, coupled with Monte Carlo and other 3D transfer methods, are providing a better understanding of the dependence of radiation on cloud inhomogeneity, and to suggest new retrieval algorithms appropriate for inhomogeneous clouds. The international "Intercomparison of 3D Radiation Codes" or I3RC, program is coordinating and evaluating the variety of 3D radiative transfer methods now available, and to make them more widely available. Information is on the Web at: http://i3rc.gsfc.nasa.gov/. Input consists of selected cloud fields derived from data sources such as radar, microwave and satellite, and from models involved in the GEWEX Cloud Systems Studies. Output is selected radiative quantities that characterize the large-scale properties of the fields of radiative fluxes and heating. Several example cloud fields will be used to illustrate. I3RC is currently implementing an "open source" 3d code capable of solving the baseline cases. Maintenance of this effort is one of the goals of a new 3DRT Working Group under the International Radiation Commission. It is hoped that the 3DRT WG will include active participation by land and ocean modelers as well, such as 3D vegetation modelers participating in RAMI.

  14. 3-D object recognition using 2-D views.

    PubMed

    Li, Wenjing; Bebis, George; Bourbakis, Nikolaos G

    2008-11-01

    We consider the problem of recognizing 3-D objects from 2-D images using geometric models and assuming different viewing angles and positions. Our goal is to recognize and localize instances of specific objects (i.e., model-based) in a scene. This is in contrast to category-based object recognition methods where the goal is to search for instances of objects that belong to a certain visual category (e.g., faces or cars). The key contribution of our work is improving 3-D object recognition by integrating Algebraic Functions of Views (AFoVs), a powerful framework for predicting the geometric appearance of an object due to viewpoint changes, with indexing and learning. During training, we compute the space of views that groups of object features can produce under the assumption of 3-D linear transformations, by combining a small number of reference views that contain the object features using AFoVs. Unrealistic views (e.g., due to the assumption of 3-D linear transformations) are eliminated by imposing a pair of rigidity constraints based on knowledge of the transformation between the reference views of the object. To represent the space of views that an object can produce compactly while allowing efficient hypothesis generation during recognition, we propose combining indexing with learning in two stages. In the first stage, we sample the space of views of an object sparsely and represent information about the samples using indexing. In the second stage, we build probabilistic models of shape appearance by sampling the space of views of the object densely and learning the manifold formed by the samples. Learning employs the Expectation-Maximization (EM) algorithm and takes place in a "universal," lower-dimensional, space computed through Random Projection (RP). During recognition, we extract groups of point features from the scene and we use indexing to retrieve the most feasible model groups that might have produced them (i.e., hypothesis generation). The likelihood

  15. Rapid 360 degree imaging and stitching of 3D objects using multiple precision 3D cameras

    NASA Astrophysics Data System (ADS)

    Lu, Thomas; Yin, Stuart; Zhang, Jianzhong; Li, Jiangan; Wu, Frank

    2008-02-01

    In this paper, we present the system architecture of a 360 degree view 3D imaging system. The system consists of multiple 3D sensors synchronized to take 3D images around the object. Each 3D camera employs a single high-resolution digital camera and a color-coded light projector. The cameras are synchronized to rapidly capture the 3D and color information of a static object or a live person. The color encoded structure lighting ensures the precise reconstruction of the depth of the object. A 3D imaging system architecture is presented. The architecture employs the displacement of the camera and the projector to triangulate the depth information. The 3D camera system has achieved high depth resolution down to 0.1mm on a human head sized object and 360 degree imaging capability.

  16. 3D shape measurements for non-diffusive objects using fringe projection techniques

    NASA Astrophysics Data System (ADS)

    Su, Wei-Hung; Tseng, Bae-Heng; Cheng, Nai-Jen

    2013-09-01

    A scanning approach using holographic techniques to perform the 3D shape measurement for a non-diffusive object is proposed. Even though the depth discontinuity on the inspected surface is pretty high, the proposed method can retrieve the 3D shape precisely.

  17. 3D PDF - a means of public access to geological 3D - objects, using the example of GTA3D

    NASA Astrophysics Data System (ADS)

    Slaby, Mark-Fabian; Reimann, Rüdiger

    2013-04-01

    In geology, 3D modeling has become very important. In the past, two-dimensional data such as isolines, drilling profiles, or cross-sections based on those, were used to illustrate the subsurface geology, whereas now, we can create complex digital 3D models. These models are produced with special software, such as GOCAD ®. The models can be viewed, only through the software used to create them, or through viewers available for free. The platform-independent PDF (Portable Document Format), enforced by Adobe, has found a wide distribution. This format has constantly evolved over time. Meanwhile, it is possible to display CAD data in an Adobe 3D PDF file with the free Adobe Reader (version 7). In a 3D PDF, a 3D model is freely rotatable and can be assembled from a plurality of objects, which can thus be viewed from all directions on their own. In addition, it is possible to create moveable cross-sections (profiles), and to assign transparency to the objects. Based on industry-standard CAD software, 3D PDFs can be generated from a large number of formats, or even be exported directly from this software. In geoinformatics, different approaches to creating 3D PDFs exist. The intent of the Authority for Mining, Energy and Geology to allow free access to the models of the Geotectonic Atlas (GTA3D), could not be realized with standard software solutions. A specially designed code converts the 3D objects to VRML (Virtual Reality Modeling Language). VRML is one of the few formats that allow using image files (maps) as textures, and to represent colors and shapes correctly. The files were merged in Acrobat X Pro, and a 3D PDF was generated subsequently. A topographic map, a display of geographic directions and horizontal and vertical scales help to facilitate the use.

  18. Interactive photogrammetric system for mapping 3D objects

    NASA Astrophysics Data System (ADS)

    Knopp, Dave E.

    1990-08-01

    A new system, FOTO-G, has been developed for 3D photogrammetric applications. It is a production-oriented software system designed to work with highly unconventional photogrammetric image configurations which result when photographing 3D objects. A demonstration with imagery from an actual 3D-mapping project is reported.

  19. 3D model retrieval using probability density-based shape descriptors.

    PubMed

    Akgül, Ceyhun Burak; Sankur, Bülent; Yemez, Yücel; Schmitt, Francis

    2009-06-01

    We address content-based retrieval of complete 3D object models by a probabilistic generative description of local shape properties. The proposed shape description framework characterizes a 3D object with sampled multivariate probability density functions of its local surface features. This density-based descriptor can be efficiently computed via kernel density estimation (KDE) coupled with fast Gauss transform. The non-parametric KDE technique allows reliable characterization of a diverse set of shapes and yields descriptors which remain relatively insensitive to small shape perturbations and mesh resolution. Density-based characterization also induces a permutation property which can be used to guarantee invariance at the shape matching stage. As proven by extensive retrieval experiments on several 3D databases, our framework provides state-of-the-art discrimination over a broad and heterogeneous set of shape categories. PMID:19372614

  20. 3D model-based still image object categorization

    NASA Astrophysics Data System (ADS)

    Petre, Raluca-Diana; Zaharia, Titus

    2011-09-01

    This paper proposes a novel recognition scheme algorithm for semantic labeling of 2D object present in still images. The principle consists of matching unknown 2D objects with categorized 3D models in order to infer the semantics of the 3D object to the image. We tested our new recognition framework by using the MPEG-7 and Princeton 3D model databases in order to label unknown images randomly selected from the web. Results obtained show promising performances, with recognition rate up to 84%, which opens interesting perspectives in terms of semantic metadata extraction from still images/videos.

  1. Phase Sensitive Cueing for 3D Objects in Overhead Images

    SciTech Connect

    Paglieroni, D

    2005-02-04

    Locating specific 3D objects in overhead images is an important problem in many remote sensing applications. 3D objects may contain either one connected component or multiple disconnected components. Solutions must accommodate images acquired with diverse sensors at various times of the day, in various seasons of the year, or under various weather conditions. Moreover, the physical manifestation of a 3D object with fixed physical dimensions in an overhead image is highly dependent on object physical dimensions, object position/orientation, image spatial resolution, and imaging geometry (e.g., obliqueness). This paper describes a two-stage computer-assisted approach for locating 3D objects in overhead images. In the matching stage, the computer matches models of 3D objects to overhead images. The strongest degree of match over all object orientations is computed at each pixel. Unambiguous local maxima in the degree of match as a function of pixel location are then found. In the cueing stage, the computer sorts image thumbnails in descending order of figure-of-merit and presents them to human analysts for visual inspection and interpretation. The figure-of-merit associated with an image thumbnail is computed from the degrees of match to a 3D object model associated with unambiguous local maxima that lie within the thumbnail. This form of computer assistance is invaluable when most of the relevant thumbnails are highly ranked, and the amount of inspection time needed is much less for the highly ranked thumbnails than for images as a whole.

  2. An Evaluative Review of Simulated Dynamic Smart 3d Objects

    NASA Astrophysics Data System (ADS)

    Romeijn, H.; Sheth, F.; Pettit, C. J.

    2012-07-01

    Three-dimensional (3D) modelling of plants can be an asset for creating agricultural based visualisation products. The continuum of 3D plants models ranges from static to dynamic objects, also known as smart 3D objects. There is an increasing requirement for smarter simulated 3D objects that are attributed mathematically and/or from biological inputs. A systematic approach to plant simulation offers significant advantages to applications in agricultural research, particularly in simulating plant behaviour and the influences of external environmental factors. This approach of 3D plant object visualisation is primarily evident from the visualisation of plants using photographed billboarded images, to more advanced procedural models that come closer to simulating realistic virtual plants. However, few programs model physical reactions of plants to external factors and even fewer are able to grow plants based on mathematical and/or biological parameters. In this paper, we undertake an evaluation of plant-based object simulation programs currently available, with a focus upon the components and techniques involved in producing these objects. Through an analytical review process we consider the strengths and weaknesses of several program packages, the features and use of these programs and the possible opportunities in deploying these for creating smart 3D plant-based objects to support agricultural research and natural resource management. In creating smart 3D objects the model needs to be informed by both plant physiology and phenology. Expert knowledge will frame the parameters and procedures that will attribute the object and allow the simulation of dynamic virtual plants. Ultimately, biologically smart 3D virtual plants that react to changes within an environment could be an effective medium to visually represent landscapes and communicate land management scenarios and practices to planners and decision-makers.

  3. 3D laser imaging for concealed object identification

    NASA Astrophysics Data System (ADS)

    Berechet, Ion; Berginc, Gérard; Berechet, Stefan

    2014-09-01

    This paper deals with new optical non-conventional 3D laser imaging. Optical non-conventional imaging explores the advantages of laser imaging to form a three-dimensional image of the scene. 3D laser imaging can be used for threedimensional medical imaging, topography, surveillance, robotic vision because of ability to detect and recognize objects. In this paper, we present a 3D laser imaging for concealed object identification. The objective of this new 3D laser imaging is to provide the user a complete 3D reconstruction of the concealed object from available 2D data limited in number and with low representativeness. The 2D laser data used in this paper come from simulations that are based on the calculation of the laser interactions with the different interfaces of the scene of interest and from experimental results. We show the global 3D reconstruction procedures capable to separate objects from foliage and reconstruct a threedimensional image of the considered object. In this paper, we present examples of reconstruction and completion of three-dimensional images and we analyse the different parameters of the identification process such as resolution, the scenario of camouflage, noise impact and lacunarity degree.

  4. Multi-Modal Clique-Graph Matching for View-Based 3D Model Retrieval.

    PubMed

    Liu, An-An; Nie, Wei-Zhi; Gao, Yue; Su, Yu-Ting

    2016-05-01

    Multi-view matching is an important but a challenging task in view-based 3D model retrieval. To address this challenge, we propose an original multi-modal clique graph (MCG) matching method in this paper. We systematically present a method for MCG generation that is composed of cliques, which consist of neighbor nodes in multi-modal feature space and hyper-edges that link pairwise cliques. Moreover, we propose an image set-based clique/edgewise similarity measure to address the issue of the set-to-set distance measure, which is the core problem in MCG matching. The proposed MCG provides the following benefits: 1) preserves the local and global attributes of a graph with the designed structure; 2) eliminates redundant and noisy information by strengthening inliers while suppressing outliers; and 3) avoids the difficulty of defining high-order attributes and solving hyper-graph matching. We validate the MCG-based 3D model retrieval using three popular single-modal data sets and one novel multi-modal data set. Extensive experiments show the superiority of the proposed method through comparisons. Moreover, we contribute a novel real-world 3D object data set, the multi-view RGB-D object data set. To the best of our knowledge, it is the largest real-world 3D object data set containing multi-modal and multi-view information. PMID:26978821

  5. Embedding objects during 3D printing to add new functionalities.

    PubMed

    Yuen, Po Ki

    2016-07-01

    A novel method for integrating and embedding objects to add new functionalities during 3D printing based on fused deposition modeling (FDM) (also known as fused filament fabrication or molten polymer deposition) is presented. Unlike typical 3D printing, FDM-based 3D printing could allow objects to be integrated and embedded during 3D printing and the FDM-based 3D printed devices do not typically require any post-processing and finishing. Thus, various fluidic devices with integrated glass cover slips or polystyrene films with and without an embedded porous membrane, and optical devices with embedded Corning(®) Fibrance™ Light-Diffusing Fiber were 3D printed to demonstrate the versatility of the FDM-based 3D printing and embedding method. Fluid perfusion flow experiments with a blue colored food dye solution were used to visually confirm fluid flow and/or fluid perfusion through the embedded porous membrane in the 3D printed fluidic devices. Similar to typical 3D printed devices, FDM-based 3D printed devices are translucent at best unless post-polishing is performed and optical transparency is highly desirable in any fluidic devices; integrated glass cover slips or polystyrene films would provide a perfect optical transparent window for observation and visualization. In addition, they also provide a compatible flat smooth surface for biological or biomolecular applications. The 3D printed fluidic devices with an embedded porous membrane are applicable to biological or chemical applications such as continuous perfusion cell culture or biocatalytic synthesis but without the need for any post-device assembly and finishing. The 3D printed devices with embedded Corning(®) Fibrance™ Light-Diffusing Fiber would have applications in display, illumination, or optical applications. Furthermore, the FDM-based 3D printing and embedding method could also be utilized to print casting molds with an integrated glass bottom for polydimethylsiloxane (PDMS) device replication

  6. Tomographic compressive holographic reconstruction of 3D objects

    NASA Astrophysics Data System (ADS)

    Nehmetallah, G.; Williams, L.; Banerjee, P. P.

    2012-10-01

    Compressive holography with multiple projection tomography is applied to solve the inverse ill-posed problem of reconstruction of 3D objects with high axial accuracy. To visualize the 3D shape, we propose Digital Tomographic Compressive Holography (DiTCH), where projections from more than one direction as in tomographic imaging systems can be employed, so that a 3D shape with better axial resolution can be reconstructed. We compare DiTCH with single-beam holographic tomography (SHOT) which is based on Fresnel back-propagation. A brief theory of DiTCH is presented, and experimental results of 3D shape reconstruction of objects using DITCH and SHOT are compared.

  7. A Primitive-Based 3D Object Recognition System

    NASA Astrophysics Data System (ADS)

    Dhawan, Atam P.

    1988-08-01

    A knowledge-based 3D object recognition system has been developed. The system uses the hierarchical structural, geometrical and relational knowledge in matching the 3D object models to the image data through pre-defined primitives. The primitives, we have selected, to begin with, are 3D boxes, cylinders, and spheres. These primitives as viewed from different angles covering complete 3D rotation range are stored in a "Primitive-Viewing Knowledge-Base" in form of hierarchical structural and relational graphs. The knowledge-based system then hypothesizes about the viewing angle and decomposes the segmented image data into valid primitives. A rough 3D structural and relational description is made on the basis of recognized 3D primitives. This description is now used in the detailed high-level frame-based structural and relational matching. The system has several expert and knowledge-based systems working in both stand-alone and cooperative modes to provide multi-level processing. This multi-level processing utilizes both bottom-up (data-driven) and top-down (model-driven) approaches in order to acquire sufficient knowledge to accept or reject any hypothesis for matching or recognizing the objects in the given image.

  8. Algorithms for Haptic Rendering of 3D Objects

    NASA Technical Reports Server (NTRS)

    Basdogan, Cagatay; Ho, Chih-Hao; Srinavasan, Mandayam

    2003-01-01

    Algorithms have been developed to provide haptic rendering of three-dimensional (3D) objects in virtual (that is, computationally simulated) environments. The goal of haptic rendering is to generate tactual displays of the shapes, hardnesses, surface textures, and frictional properties of 3D objects in real time. Haptic rendering is a major element of the emerging field of computer haptics, which invites comparison with computer graphics. We have already seen various applications of computer haptics in the areas of medicine (surgical simulation, telemedicine, haptic user interfaces for blind people, and rehabilitation of patients with neurological disorders), entertainment (3D painting, character animation, morphing, and sculpting), mechanical design (path planning and assembly sequencing), and scientific visualization (geophysical data analysis and molecular manipulation).

  9. Key techniques for vision measurement of 3D object surface

    NASA Astrophysics Data System (ADS)

    Yang, Huachao; Zhang, Shubi; Guo, Guangli; Liu, Chao; Yu, Ruipeng

    2006-11-01

    Digital close-range photogrammetry system and machine vision are widely used in production control, quality inspection. The main aim is to provide accurate 3D objects or reconstruction of an object surface and give an expression to an object shape. First, the key techniques of camera calibration and target image positioning for 3D object surface vision measurement were briefly reviewed and analyzed in this paper. Then, an innovative and effect method for precise space coordinates measurements was proposed. Test research proved that the thought and methods we proposed about image segmentation, detection and positioning of circular marks were effective and valid. A propriety weight value for adding parameters, control points and orientation elements in bundle adjustment with self-calibration are advantageous to gaining high accuracy of space coordinates. The RMS error of check points is less than +/-1 mm, which can meet the requirement in industrial measurement with high accuracy.

  10. 3-D Object Recognition from Point Cloud Data

    NASA Astrophysics Data System (ADS)

    Smith, W.; Walker, A. S.; Zhang, B.

    2011-09-01

    The market for real-time 3-D mapping includes not only traditional geospatial applications but also navigation of unmanned autonomous vehicles (UAVs). Massively parallel processes such as graphics processing unit (GPU) computing make real-time 3-D object recognition and mapping achievable. Geospatial technologies such as digital photogrammetry and GIS offer advanced capabilities to produce 2-D and 3-D static maps using UAV data. The goal is to develop real-time UAV navigation through increased automation. It is challenging for a computer to identify a 3-D object such as a car, a tree or a house, yet automatic 3-D object recognition is essential to increasing the productivity of geospatial data such as 3-D city site models. In the past three decades, researchers have used radiometric properties to identify objects in digital imagery with limited success, because these properties vary considerably from image to image. Consequently, our team has developed software that recognizes certain types of 3-D objects within 3-D point clouds. Although our software is developed for modeling, simulation and visualization, it has the potential to be valuable in robotics and UAV applications. The locations and shapes of 3-D objects such as buildings and trees are easily recognizable by a human from a brief glance at a representation of a point cloud such as terrain-shaded relief. The algorithms to extract these objects have been developed and require only the point cloud and minimal human inputs such as a set of limits on building size and a request to turn on a squaring option. The algorithms use both digital surface model (DSM) and digital elevation model (DEM), so software has also been developed to derive the latter from the former. The process continues through the following steps: identify and group 3-D object points into regions; separate buildings and houses from trees; trace region boundaries; regularize and simplify boundary polygons; construct complex roofs. Several case

  11. Human efficiency for recognizing 3-D objects in luminance noise.

    PubMed

    Tjan, B S; Braje, W L; Legge, G E; Kersten, D

    1995-11-01

    The purpose of this study was to establish how efficiently humans use visual information to recognize simple 3-D objects. The stimuli were computer-rendered images of four simple 3-D objects--wedge, cone, cylinder, and pyramid--each rendered from 8 randomly chosen viewing positions as shaded objects, line drawings, or silhouettes. The objects were presented in static, 2-D Gaussian luminance noise. The observer's task was to indicate which of the four objects had been presented. We obtained human contrast thresholds for recognition, and compared these to an ideal observer's thresholds to obtain efficiencies. In two auxiliary experiments, we measured efficiencies for object detection and letter recognition. Our results showed that human object-recognition efficiency is low (3-8%) when compared to efficiencies reported for some other visual-information processing tasks. The low efficiency means that human recognition performance is limited primarily by factors intrinsic to the observer rather than the information content of the stimuli. We found three factors that play a large role in accounting for low object-recognition efficiency: stimulus size, spatial uncertainty, and detection efficiency. Four other factors play a smaller role in limiting object-recognition efficiency: observers' internal noise, stimulus rendering condition, stimulus familiarity, and categorization across views. PMID:8533342

  12. Medical image retrieval system using multiple features from 3D ROIs

    NASA Astrophysics Data System (ADS)

    Lu, Hongbing; Wang, Weiwei; Liao, Qimei; Zhang, Guopeng; Zhou, Zhiming

    2012-02-01

    Compared to a retrieval using global image features, features extracted from regions of interest (ROIs) that reflect distribution patterns of abnormalities would benefit more for content-based medical image retrieval (CBMIR) systems. Currently, most CBMIR systems have been designed for 2D ROIs, which cannot reflect 3D anatomical features and region distribution of lesions comprehensively. To further improve the accuracy of image retrieval, we proposed a retrieval method with 3D features including both geometric features such as Shape Index (SI) and Curvedness (CV) and texture features derived from 3D Gray Level Co-occurrence Matrix, which were extracted from 3D ROIs, based on our previous 2D medical images retrieval system. The system was evaluated with 20 volume CT datasets for colon polyp detection. Preliminary experiments indicated that the integration of morphological features with texture features could improve retrieval performance greatly. The retrieval result using features extracted from 3D ROIs accorded better with the diagnosis from optical colonoscopy than that based on features from 2D ROIs. With the test database of images, the average accuracy rate for 3D retrieval method was 76.6%, indicating its potential value in clinical application.

  13. The Visual Priming of Motion-Defined 3D Objects

    PubMed Central

    Jiang, Xiong; Jiang, Yang

    2015-01-01

    The perception of a stimulus can be influenced by previous perceptual experience, a phenomenon known as perceptual priming. However, there has been limited investigation on perceptual priming of shape perception of three-dimensional object structures defined by moving dots. Here we examined the perceptual priming of a 3D object shape defined purely by motion-in-depth cues (i.e., Shape-From-Motion, SFM) using a classic prime-target paradigm. The results from the first two experiments revealed a significant increase in accuracy when a “cloudy” SFM stimulus (whose object structure was difficult to recognize due to the presence of strong noise) was preceded by an unambiguous SFM that clearly defined the same transparent 3D shape. In contrast, results from Experiment 3 revealed no change in accuracy when a “cloudy” SFM stimulus was preceded by a static shape or a semantic word that defined the same object shape. Instead, there was a significant decrease in accuracy when preceded by a static shape or a semantic word that defined a different object shape. These results suggested that the perception of a noisy SFM stimulus can be facilitated by a preceding unambiguous SFM stimulus—but not a static image or a semantic stimulus—that defined the same shape. The potential neural and computational mechanisms underlying the difference in priming are discussed. PMID:26658496

  14. Large-scale objective phenotyping of 3D facial morphology

    PubMed Central

    Hammond, Peter; Suttie, Michael

    2012-01-01

    Abnormal phenotypes have played significant roles in the discovery of gene function, but organized collection of phenotype data has been overshadowed by developments in sequencing technology. In order to study phenotypes systematically, large-scale projects with standardized objective assessment across populations are considered necessary. The report of the 2006 Human Variome Project meeting recommended documentation of phenotypes through electronic means by collaborative groups of computational scientists and clinicians using standard, structured descriptions of disease-specific phenotypes. In this report, we describe progress over the past decade in 3D digital imaging and shape analysis of the face, and future prospects for large-scale facial phenotyping. Illustrative examples are given throughout using a collection of 1107 3D face images of healthy controls and individuals with a range of genetic conditions involving facial dysmorphism. PMID:22434506

  15. Scale Space Graph Representation and Kernel Matching for Non Rigid and Textured 3D Shape Retrieval.

    PubMed

    Garro, Valeria; Giachetti, Andrea

    2016-06-01

    In this paper we introduce a novel framework for 3D object retrieval that relies on tree-based shape representations (TreeSha) derived from the analysis of the scale-space of the Auto Diffusion Function (ADF) and on specialized graph kernels designed for their comparison. By coupling maxima of the Auto Diffusion Function with the related basins of attraction, we can link the information at different scales encoding spatial relationships in a graph description that is isometry invariant and can easily incorporate texture and additional geometrical information as node and edge features. Using custom graph kernels it is then possible to estimate shape dissimilarities adapted to different specific tasks and on different categories of models, making the procedure a powerful and flexible tool for shape recognition and retrieval. Experimental results demonstrate that the method can provide retrieval scores similar or better than state-of-the-art on textured and non textured shape retrieval benchmarks and give interesting insights on effectiveness of different shape descriptors and graph kernels. PMID:26372206

  16. Retrieval of humidity and temperature profiles over the oceans from INSAT 3D satellite radiances

    NASA Astrophysics Data System (ADS)

    Krishnamoorthy, C.; Kumar, Deo; Balaji, C.

    2016-03-01

    In this study, retrieval of temperature and humidity profiles of atmosphere from INSAT 3D-observed radiances has been accomplished. As the first step, a fast forward radiative transfer model using an Artificial neural network has been developed and it was proven to be highly effective, giving a correlation coefficient of 0.97. In order to develop this, a diverse set of physics-based clear sky profiles of pressure ( P), temperature ( T) and specific humidity ( q) has been developed. The developed database was further used for geophysical retrieval experiments in two different frameworks, namely, an ANN and Bayesian estimation. The neural network retrievals were performed for three different cases, viz., temperature only retrieval, humidity only retrieval and combined retrieval. The temperature/humidity only ANN retrievals were found superior to combined retrieval using an ANN. Furthermore, Bayesian estimation showed superior results when compared with the combined ANN retrievals.

  17. Land surface temperature from INSAT-3D imager data: Retrieval and assimilation in NWP model

    NASA Astrophysics Data System (ADS)

    Singh, Randhir; Singh, Charu; Ojha, Satya P.; Kumar, A. Senthil; Kishtawal, C. M.; Kumar, A. S. Kiran

    2016-06-01

    A new algorithm is developed for retrieving the land surface temperature (LST) from the imager radiance observations on board geostationary operational Indian National Satellite (INSAT-3D). The algorithm is developed using the two thermal infrared channels (TIR1 10.3-11.3 µm and TIR2 11.5-12.5 µm) via genetic algorithm (GA). The transfer function that relates LST and thermal radiances is developed using radiative transfer model simulated database. The developed algorithm has been applied on the INSAT-3D observed radiances, and LST retrieved from the developed algorithm has been validated with Moderate Resolution Imaging Spectroradiometer land surface temperature (LST) product. The developed algorithm demonstrates a good accuracy, without significant bias and standard deviations of 1.78 K and 1.41 K during daytime and nighttime, respectively. The newly proposed algorithm performs better than the operational algorithm used for LST retrieval from INSAT-3D satellite. Further, a set of data assimilation experiments is conducted with the Weather Research and Forecasting (WRF) model to assess the impact of INSAT-3D LST on model forecast skill over the Indian region. The assimilation experiments demonstrated a positive impact of the assimilated INSAT-3D LST, particularly on the lower tropospheric temperature and moisture forecasts. The temperature and moisture forecast errors are reduced (as large as 8-10%) with the assimilation of INSAT-3D LST, when compared to forecasts that were obtained without the assimilation of INSAT-3D LST. Results of the additional experiments of comparative performance of two LST products, retrieved from operational and newly proposed algorithms, indicate that the impact of INSAT-3D LST retrieved using newly proposed algorithm is significantly larger compared to the impact of INSAT-3D LST retrieved using operational algorithm.

  18. Fully automatic 3D digitization of unknown objects

    NASA Astrophysics Data System (ADS)

    Rozenwald, Gabriel F.; Seulin, Ralph; Fougerolle, Yohan D.

    2010-01-01

    This paper presents a complete system for 3D digitization of objects assuming no prior knowledge on its shape. The proposed methodology is applied to a digitization cell composed of a fringe projection scanner head, a robotic arm with 6 degrees of freedom (DoF), and a turntable. A two-step approach is used to automatically guide the scanning process. The first step uses the concept of Mass Vector Chains (MVC) to perform an initial scanning. The second step directs the scanner to remaining holes of the model. Post-processing of the data is also addressed. Tests with real objects were performed and results of digitization length in time and number of views are provided along with estimated surface coverage.

  19. Automated full-3D shape measurement of cultural heritage objects

    NASA Astrophysics Data System (ADS)

    Sitnik, Robert; Karaszewski, Maciej; Zaluski, Wojciech; Bolewicki, Pawel

    2009-07-01

    In this paper a fully automated 3D shape measurement system is presented. It consists of rotary stage for cultural heritage objects placement, vertical linear stage with mounted robot arm (with six degrees of freedom) and structured light measurement set-up mounted to its head. All these manipulation devices are automatically controlled by collision detection and next-best-view calculation modules. The goal of whole system is to automatically (without any user attention) and rapidly (from days and weeks to hours) measure whole object. Measurement head is automatically calibrated by the system and its possible working volume starts from centimeters and ends up to one meter. We present some measurement results with different working scenarios along with discussion about its possible applications.

  20. Phase Sensitive Cueing for 3D Objects in Overhead Images

    SciTech Connect

    Paglieroni, D W; Eppler, W G; Poland, D N

    2005-02-18

    A 3D solid model-aided object cueing method that matches phase angles of directional derivative vectors at image pixels to phase angles of vectors normal to projected model edges is described. It is intended for finding specific types of objects at arbitrary position and orientation in overhead images, independent of spatial resolution, obliqueness, acquisition conditions, and type of imaging sensor. It is shown that the phase similarity measure can be efficiently evaluated over all combinations of model position and orientation using the FFT. The highest degree of similarity over all model orientations is captured in a match surface of similarity values vs. model position. Unambiguous peaks in this surface are sorted in descending order of similarity value, and the small image thumbnails that contain them are presented to human analysts for inspection in sorted order.

  1. Objective 3D face recognition: Evolution, approaches and challenges.

    PubMed

    Smeets, Dirk; Claes, Peter; Vandermeulen, Dirk; Clement, John Gerald

    2010-09-10

    Face recognition is a natural human ability and a widely accepted identification and authentication method. In modern legal settings, a lot of credence is placed on identifications made by eyewitnesses. Consequently these are based on human perception which is often flawed and can lead to situations where identity is disputed. Therefore, there is a clear need to secure identifications in an objective way based on anthropometric measures. Anthropometry has existed for many years and has evolved with each advent of new technology and computing power. As a result of this, face recognition methodology has shifted from a purely 2D image-based approach to the use of 3D facial shape. However, one of the main challenges still remaining is the non-rigid structure of the face, which can change permanently over varying time-scales and briefly with facial expressions. The majority of face recognition methods have been developed by scientists with a very technical background such as biometry, pattern recognition and computer vision. This article strives to bridge the gap between these communities and the forensic science end-users. A concise review of face recognition using 3D shape is given. Methods using 3D shape applied to data embodying facial expressions are tabulated for reference. From this list a categorization of different strategies to deal with expressions is presented. The underlying concepts and practical issues relating to the application of each strategy are given, without going into technical details. The discussion clearly articulates the justification to establish archival, reference databases to compare and evaluate different strategies. PMID:20395086

  2. Large distance 3D imaging of hidden objects

    NASA Astrophysics Data System (ADS)

    Rozban, Daniel; Aharon Akram, Avihai; Kopeika, N. S.; Abramovich, A.; Levanon, Assaf

    2014-06-01

    Imaging systems in millimeter waves are required for applications in medicine, communications, homeland security, and space technology. This is because there is no known ionization hazard for biological tissue, and atmospheric attenuation in this range of the spectrum is low compared to that of infrared and optical rays. The lack of an inexpensive room temperature detector makes it difficult to give a suitable real time implement for the above applications. A 3D MMW imaging system based on chirp radar was studied previously using a scanning imaging system of a single detector. The system presented here proposes to employ a chirp radar method with Glow Discharge Detector (GDD) Focal Plane Array (FPA of plasma based detectors) using heterodyne detection. The intensity at each pixel in the GDD FPA yields the usual 2D image. The value of the I-F frequency yields the range information at each pixel. This will enable 3D MMW imaging. In this work we experimentally demonstrate the feasibility of implementing an imaging system based on radar principles and FPA of inexpensive detectors. This imaging system is shown to be capable of imaging objects from distances of at least 10 meters.

  3. 3-D Interpolation in Object Perception: Evidence from an Objective Performance Paradigm

    ERIC Educational Resources Information Center

    Kellman, Philip J.; Garrigan, Patrick; Shipley, Thomas F.; Yin, Carol; Machado, Liana

    2005-01-01

    Object perception requires interpolation processes that connect visible regions despite spatial gaps. Some research has suggested that interpolation may be a 3-D process, but objective performance data and evidence about the conditions leading to interpolation are needed. The authors developed an objective performance paradigm for testing 3-D…

  4. Object Segmentation and Ground Truth in 3D Embryonic Imaging

    PubMed Central

    Rajasekaran, Bhavna; Uriu, Koichiro; Valentin, Guillaume; Tinevez, Jean-Yves; Oates, Andrew C.

    2016-01-01

    Many questions in developmental biology depend on measuring the position and movement of individual cells within developing embryos. Yet, tools that provide this data are often challenged by high cell density and their accuracy is difficult to measure. Here, we present a three-step procedure to address this problem. Step one is a novel segmentation algorithm based on image derivatives that, in combination with selective post-processing, reliably and automatically segments cell nuclei from images of densely packed tissue. Step two is a quantitative validation using synthetic images to ascertain the efficiency of the algorithm with respect to signal-to-noise ratio and object density. Finally, we propose an original method to generate reliable and experimentally faithful ground truth datasets: Sparse-dense dual-labeled embryo chimeras are used to unambiguously measure segmentation errors within experimental data. Together, the three steps outlined here establish a robust, iterative procedure to fine-tune image analysis algorithms and microscopy settings associated with embryonic 3D image data sets. PMID:27332860

  5. Approximation of a foreign object using x-rays, reference photographs and 3D reconstruction techniques.

    PubMed

    Briggs, Matt; Shanmugam, Mohan

    2013-12-01

    This case study describes how a 3D animation was created to approximate the depth and angle of a foreign object (metal bar) that had become embedded into a patient's head. A pre-operative CT scan was not available as the patient could not fit though the CT scanner, therefore a post surgical CT scan, x-ray and photographic images were used. A surface render was made of the skull and imported into Blender (a 3D animation application). The metal bar was not available, however images of a similar object that was retrieved from the scene by the ambulance crew were used to recreate a 3D model. The x-ray images were then imported into Blender and used as background images in order to align the skull reconstruction and metal bar at the correct depth/angle. A 3D animation was then created to fully illustrate the angle and depth of the iron bar in the skull. PMID:24206011

  6. 3D X-ray tomography to evaluate volumetric objects

    NASA Astrophysics Data System (ADS)

    de Oliveira, Luís. F.; Lopes, Ricardo T.; de Jesus, Edgar F. O.; Braz, Delson

    2003-06-01

    The 3D-CT and stereological techniques are used concomitantly. The quantitative stereology yields measurements that reflects areas, volumes, lengths, rates and frequencies of the test body. Two others quantification, connectivity and anisotropy, can be used as well to complete the analysis. In this paper, it is presented the application of 3D-CT and the stereological quantification to analyze a special kind of test body: ceramic filters which have an internal structure similar to cancellous bone. The stereology is adapted to work with the 3D nature of the tomographic data. It is presented too the results of connectivity and anisotropy.

  7. Image-Based Airborne LiDAR Point Cloud Encoding for 3d Building Model Retrieval

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Chen; Lin, Chao-Hung

    2016-06-01

    With the development of Web 2.0 and cyber city modeling, an increasing number of 3D models have been available on web-based model-sharing platforms with many applications such as navigation, urban planning, and virtual reality. Based on the concept of data reuse, a 3D model retrieval system is proposed to retrieve building models similar to a user-specified query. The basic idea behind this system is to reuse these existing 3D building models instead of reconstruction from point clouds. To efficiently retrieve models, the models in databases are compactly encoded by using a shape descriptor generally. However, most of the geometric descriptors in related works are applied to polygonal models. In this study, the input query of the model retrieval system is a point cloud acquired by Light Detection and Ranging (LiDAR) systems because of the efficient scene scanning and spatial information collection. Using Point clouds with sparse, noisy, and incomplete sampling as input queries is more difficult than that by using 3D models. Because that the building roof is more informative than other parts in the airborne LiDAR point cloud, an image-based approach is proposed to encode both point clouds from input queries and 3D models in databases. The main goal of data encoding is that the models in the database and input point clouds can be consistently encoded. Firstly, top-view depth images of buildings are generated to represent the geometry surface of a building roof. Secondly, geometric features are extracted from depth images based on height, edge and plane of building. Finally, descriptors can be extracted by spatial histograms and used in 3D model retrieval system. For data retrieval, the models are retrieved by matching the encoding coefficients of point clouds and building models. In experiments, a database including about 900,000 3D models collected from the Internet is used for evaluation of data retrieval. The results of the proposed method show a clear superiority

  8. High efficient methods of content-based 3D model retrieval

    NASA Astrophysics Data System (ADS)

    Wu, Yuanhao; Tian, Ling; Li, Chenggang

    2013-03-01

    Content-based 3D model retrieval is of great help to facilitate the reuse of existing designs and to inspire designers during conceptual design. However, there is still a gap to apply it in industry due to the low time efficiency. This paper presents two new methods with high efficiency to build a Content-based 3D model retrieval system. First, an improvement is made on the "Shape Distribution (D2)" algorithm, and a new algorithm named "Quick D2" is proposed. Four sample 3D mechanical models are used in an experiment to compare the time cost of the two algorithms. The result indicates that the time cost of Quick D2 is much lower than that of D2, while the descriptors extracted by the two algorithms are almost the same. Second, an expandable 3D model repository index method with high performance, namely, RBK index, is presented. On the basis of RBK index, the search space is pruned effectively during the search process, leading to a speed up of the whole system. The factors that influence the values of the key parameters of RBK index are discussed and an experimental method to find the optimal values of the key parameters is given. Finally, "3D Searcher", a content-based 3D model retrieval system is developed. By using the methods proposed, the time cost for the system to respond one query online is reduced by 75% on average. The system has been implemented in a manufacturing enterprise, and practical query examples during a case of the automobile rear axle design are also shown. The research method presented shows a new research perspective and can effectively improve the content-based 3D model retrieval efficiency.

  9. Reconstruction and 3D visualisation based on objective real 3D based documentation.

    PubMed

    Bolliger, Michael J; Buck, Ursula; Thali, Michael J; Bolliger, Stephan A

    2012-09-01

    Reconstructions based directly upon forensic evidence alone are called primary information. Historically this consists of documentation of findings by verbal protocols, photographs and other visual means. Currently modern imaging techniques such as 3D surface scanning and radiological methods (computer tomography, magnetic resonance imaging) are also applied. Secondary interpretation is based on facts and the examiner's experience. Usually such reconstructive expertises are given in written form, and are often enhanced by sketches. However, narrative interpretations can, especially in complex courses of action, be difficult to present and can be misunderstood. In this report we demonstrate the use of graphic reconstruction of secondary interpretation with supporting pictorial evidence, applying digital visualisation (using 'Poser') or scientific animation (using '3D Studio Max', 'Maya') and present methods of clearly distinguishing between factual documentation and examiners' interpretation based on three cases. The first case involved a pedestrian who was initially struck by a car on a motorway and was then run over by a second car. The second case involved a suicidal gunshot to the head with a rifle, in which the trigger was pushed with a rod. The third case dealt with a collision between two motorcycles. Pictorial reconstruction of the secondary interpretation of these cases has several advantages. The images enable an immediate overview, give rise to enhanced clarity, and compel the examiner to look at all details if he or she is to create a complete image. PMID:21979427

  10. Objective and subjective quality assessment of geometry compression of reconstructed 3D humans in a 3D virtual room

    NASA Astrophysics Data System (ADS)

    Mekuria, Rufael; Cesar, Pablo; Doumanis, Ioannis; Frisiello, Antonella

    2015-09-01

    Compression of 3D object based video is relevant for 3D Immersive applications. Nevertheless, the perceptual aspects of the degradation introduced by codecs for meshes and point clouds are not well understood. In this paper we evaluate the subjective and objective degradations introduced by such codecs in a state of art 3D immersive virtual room. In the 3D immersive virtual room, users are captured with multiple cameras, and their surfaces are reconstructed as photorealistic colored/textured 3D meshes or point clouds. To test the perceptual effect of compression and transmission, we render degraded versions with different frame rates in different contexts (near/far) in the scene. A quantitative subjective study with 16 users shows that negligible distortion of decoded surfaces compared to the original reconstructions can be achieved in the 3D virtual room. In addition, a qualitative task based analysis in a full prototype field trial shows increased presence, emotion, user and state recognition of the reconstructed 3D Human representation compared to animated computer avatars.

  11. Intuitive terrain reconstruction using height observation-based ground segmentation and 3D object boundary estimation.

    PubMed

    Song, Wei; Cho, Kyungeun; Um, Kyhyun; Won, Chee Sun; Sim, Sungdae

    2012-01-01

    Mobile robot operators must make rapid decisions based on information about the robot's surrounding environment. This means that terrain modeling and photorealistic visualization are required for the remote operation of mobile robots. We have produced a voxel map and textured mesh from the 2D and 3D datasets collected by a robot's array of sensors, but some upper parts of objects are beyond the sensors' measurements and these parts are missing in the terrain reconstruction result. This result is an incomplete terrain model. To solve this problem, we present a new ground segmentation method to detect non-ground data in the reconstructed voxel map. Our method uses height histograms to estimate the ground height range, and a Gibbs-Markov random field model to refine the segmentation results. To reconstruct a complete terrain model of the 3D environment, we develop a 3D boundary estimation method for non-ground objects. We apply a boundary detection technique to the 2D image, before estimating and refining the actual height values of the non-ground vertices in the reconstructed textured mesh. Our proposed methods were tested in an outdoor environment in which trees and buildings were not completely sensed. Our results show that the time required for ground segmentation is faster than that for data sensing, which is necessary for a real-time approach. In addition, those parts of objects that were not sensed are accurately recovered to retrieve their real-world appearances. PMID:23235454

  12. Intuitive Terrain Reconstruction Using Height Observation-Based Ground Segmentation and 3D Object Boundary Estimation

    PubMed Central

    Song, Wei; Cho, Kyungeun; Um, Kyhyun; Won, Chee Sun; Sim, Sungdae

    2012-01-01

    Mobile robot operators must make rapid decisions based on information about the robot’s surrounding environment. This means that terrain modeling and photorealistic visualization are required for the remote operation of mobile robots. We have produced a voxel map and textured mesh from the 2D and 3D datasets collected by a robot’s array of sensors, but some upper parts of objects are beyond the sensors’ measurements and these parts are missing in the terrain reconstruction result. This result is an incomplete terrain model. To solve this problem, we present a new ground segmentation method to detect non-ground data in the reconstructed voxel map. Our method uses height histograms to estimate the ground height range, and a Gibbs-Markov random field model to refine the segmentation results. To reconstruct a complete terrain model of the 3D environment, we develop a 3D boundary estimation method for non-ground objects. We apply a boundary detection technique to the 2D image, before estimating and refining the actual height values of the non-ground vertices in the reconstructed textured mesh. Our proposed methods were tested in an outdoor environment in which trees and buildings were not completely sensed. Our results show that the time required for ground segmentation is faster than that for data sensing, which is necessary for a real-time approach. In addition, those parts of objects that were not sensed are accurately recovered to retrieve their real-world appearances. PMID:23235454

  13. Influence of 3D Effects on 1D Aerosol Retrievals in Synthetic, Partially Clouded Scenes

    NASA Astrophysics Data System (ADS)

    Stap, F. A.; Hasekamp, O. P.; Emde, C.

    2014-12-01

    Most satellite measurements of the microphysical and radiative properties of aerosol near clouds are either strictly screened for, or hindered by sub-pixel cloud contamination. This may change with the advent of a new generation of aerosol retrieval algorithms,intended for multi-angle, multi-wavelength photo-polarimetric instruments such as POLDER3on board PARASOL, which show ability to separate between aerosol and cloud particles.In order to obtain the required computational efficiency these algorithms typically make use of 1D radiative transfer models and are thus unable to account for the 3D effects that occur in actual, partially clouded scenes.Here, we apply an aerosol retrieval algorithm, which employs a 1D radiative transfer code and the independent pixel approximation, on synthetic, 3D, partially cloudedscenes calculated with the Monte Carlo radiative transfer code MYSTIC.The influence of the 3D effects due to clouds on the retrieved microphysical and optical aerosol properties is presented and the ability of the algorithm to retrieve these properties in partially clouded scenes will be discussed.

  14. Influence of 3D Radiative Effects on Satellite Retrievals of Cloud Properties

    NASA Technical Reports Server (NTRS)

    Varnai, Tamas; Marshak, Alexander; Einaudi, Franco (Technical Monitor)

    2001-01-01

    When cloud properties are retrieved from satellite observations, the calculations apply 1D theory to the 3D world: they only consider vertical structures and ignore horizontal cloud variability. This presentation discusses how big the resulting errors can be in the operational retrievals of cloud optical thickness. A new technique was developed to estimate the magnitude of potential errors by analyzing the spatial patterns of visible and infrared images. The proposed technique was used to set error bars for optical depths retrieved from new MODIS measurements. Initial results indicate that the 1 km resolution retrievals are subject to abundant uncertainties. Averaging over 50 by 50 km areas reduces the errors, but does not remove them completely; even in the relatively simple case of high sun (30 degree zenith angle), about a fifth of the examined areas had biases larger than ten percent. As expected, errors increase substantially for more oblique illumination.

  15. Extension of RCC Topological Relations for 3d Complex Objects Components Extracted from 3d LIDAR Point Clouds

    NASA Astrophysics Data System (ADS)

    Xing, Xu-Feng; Abolfazl Mostafavia, Mir; Wang, Chen

    2016-06-01

    Topological relations are fundamental for qualitative description, querying and analysis of a 3D scene. Although topological relations for 2D objects have been extensively studied and implemented in GIS applications, their direct extension to 3D is very challenging and they cannot be directly applied to represent relations between components of complex 3D objects represented by 3D B-Rep models in R3. Herein we present an extended Region Connection Calculus (RCC) model to express and formalize topological relations between planar regions for creating 3D model represented by Boundary Representation model in R3. We proposed a new dimension extended 9-Intersection model to represent the basic relations among components of a complex object, including disjoint, meet and intersect. The last element in 3*3 matrix records the details of connection through the common parts of two regions and the intersecting line of two planes. Additionally, this model can deal with the case of planar regions with holes. Finally, the geometric information is transformed into a list of strings consisting of topological relations between two planar regions and detailed connection information. The experiments show that the proposed approach helps to identify topological relations of planar segments of point cloud automatically.

  16. Retrieval of cloud microphysical parameters from INSAT-3D: a feasibility study using radiative transfer simulations

    NASA Astrophysics Data System (ADS)

    Jinya, John; Bipasha, Paul S.

    2016-05-01

    Clouds strongly modulate the Earths energy balance and its atmosphere through their interaction with the solar and terrestrial radiation. They interact with radiation in various ways like scattering, emission and absorption. By observing these changes in radiation at different wavelength, cloud properties can be estimated. Cloud properties are of utmost importance in studying different weather and climate phenomena. At present, no satellite provides cloud microphysical parameters over the Indian region with high temporal resolution. INSAT-3D imager observations in 6 spectral channels from geostationary platform offer opportunity to study continuous cloud properties over Indian region. Visible (0.65 μm) and shortwave-infrared (1.67 μm) channel radiances can be used to retrieve cloud microphysical parameters such as cloud optical thickness (COT) and cloud effective radius (CER). In this paper, we have carried out a feasibility study with the objective of cloud microphysics retrieval. For this, an inter-comparison of 15 globally available radiative transfer models (RTM) were carried out with the aim of generating a Look-up- Table (LUT). SBDART model was chosen for the simulations. The sensitivity of each spectral channel to different cloud properties was investigated. The inputs to the RT model were configured over our study region (50°S - 50°N and 20°E - 130°E) and a large number of simulations were carried out using random input vectors to generate the LUT. The determination of cloud optical thickness and cloud effective radius from spectral reflectance measurements constitutes the inverse problem and is typically solved by comparing the measured reflectances with entries in LUT and searching for the combination of COT and CER that gives the best fit. The products are available on the website www.mosdac.gov.in

  17. Object-oriented urban 3D spatial data model organization method

    NASA Astrophysics Data System (ADS)

    Li, Jing-wen; Li, Wen-qing; Lv, Nan; Su, Tao

    2015-12-01

    This paper combined the 3d data model with object-oriented organization method, put forward the model of 3d data based on object-oriented method, implemented the city 3d model to quickly build logical semantic expression and model, solved the city 3d spatial information representation problem of the same location with multiple property and the same property with multiple locations, designed the space object structure of point, line, polygon, body for city of 3d spatial database, and provided a new thought and method for the city 3d GIS model and organization management.

  18. A Taxonomy of 3D Occluded Objects Recognition Techniques

    NASA Astrophysics Data System (ADS)

    Soleimanizadeh, Shiva; Mohamad, Dzulkifli; Saba, Tanzila; Al-ghamdi, Jarallah Saleh

    2016-03-01

    The overall performances of object recognition techniques under different condition (e.g., occlusion, viewpoint, and illumination) have been improved significantly in recent years. New applications and hardware are shifted towards digital photography, and digital media. This faces an increase in Internet usage requiring object recognition for certain applications; particularly occulded objects. However occlusion is still an issue unhandled, interlacing the relations between extracted feature points through image, research is going on to develop efficient techniques and easy to use algorithms that would help users to source images; this need to overcome problems and issues regarding occlusion. The aim of this research is to review recognition occluded objects algorithms and figure out their pros and cons to solve the occlusion problem features, which are extracted from occluded object to distinguish objects from other co-existing objects by determining the new techniques, which could differentiate the occluded fragment and sections inside an image.

  19. Easily retrievable objects among the NEO population

    NASA Astrophysics Data System (ADS)

    García Yárnoz, D.; Sanchez, J. P.; McInnes, C. R.

    2013-08-01

    Asteroids and comets are of strategic importance for science in an effort to understand the formation, evolution and composition of the Solar System. Near-Earth Objects (NEOs) are of particular interest because of their accessibility from Earth, but also because of their speculated wealth of material resources. The exploitation of these resources has long been discussed as a means to lower the cost of future space endeavours. In this paper, we consider the currently known NEO population and define a family of so-called Easily Retrievable Objects (EROs), objects that can be transported from accessible heliocentric orbits into the Earth's neighbourhood at affordable costs. The asteroid retrieval transfers are sought from the continuum of low energy transfers enabled by the dynamics of invariant manifolds; specifically, the retrieval transfers target planar, vertical Lyapunov and halo orbit families associated with the collinear equilibrium points of the Sun-Earth Circular Restricted Three Body problem. The judicious use of these dynamical features provides the best opportunity to find extremely low energy Earth transfers for asteroid material. A catalogue of asteroid retrieval candidates is then presented. Despite the highly incomplete census of very small asteroids, the ERO catalogue can already be populated with 12 different objects retrievable with less than 500 m/s of Δ v. Moreover, the approach proposed represents a robust search and ranking methodology for future retrieval candidates that can be automatically applied to the growing survey of NEOs.

  20. Frio, Yegua objectives of E. Texas 3D seismic

    SciTech Connect

    1996-07-01

    Houston companies plan to explore deeper formations along the Sabine River on the Texas and Louisiana Gulf Coast. PetroGuard Co. Inc. and Jebco Seismic Inc., Houston, jointly secured a seismic and leasing option from Hankamer family et al. on about 120 sq miles in Newton County, Tex., and Calcasieu Parish, La. PetroGuard, which specializes in oilfield rehabilitation, has production experience in the area. Historic production in the area spans three major geologic trends: Oligocene Frio/Hackberry, downdip and mid-dip Eocene Yegua, and Eocene Wilcox. In the southern part of the area, to be explored first, the trends lie at 9,000--10,000 ft, 10,000--12,000 ft, and 14,000--15,000 ft, respectively. Output Exploration Co., an affiliate of Input/Output Inc., Houston, acquired from PetroGuard and Jebco all exploratory drilling rights in the option area. Output will conduct 3D seismic operations over nearly half the acreage this summer. Data acquisition started late this spring. Output plans to use a combination of a traditional land recording system and I/O`s new RSR 24 bit radio telemetry system because the area spans environments from dry land to swamp.

  1. MODIS volcanic ash retrievals vs FALL3D transport model: a quantitative comparison

    NASA Astrophysics Data System (ADS)

    Corradini, S.; Merucci, L.; Folch, A.

    2010-12-01

    Satellite retrievals and transport models represents the key tools to monitor the volcanic clouds evolution. Because of the harming effects of fine ash particles on aircrafts, the real-time tracking and forecasting of volcanic clouds is key for aviation safety. Together with the security reasons also the economical consequences of a disruption of airports must be taken into account. The airport closures due to the recent Icelandic Eyjafjöll eruption caused millions of passengers to be stranded not only in Europe, but across the world. IATA (the International Air Transport Association) estimates that the worldwide airline industry has lost a total of about 2.5 billion of Euro during the disruption. Both security and economical issues require reliable and robust ash cloud retrievals and trajectory forecasting. The intercomparison between remote sensing and modeling is required to assure precise and reliable volcanic ash products. In this work we perform a quantitative comparison between Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals of volcanic ash cloud mass and Aerosol Optical Depth (AOD) with the FALL3D ash dispersal model. MODIS, aboard the NASA-Terra and NASA-Aqua polar satellites, is a multispectral instrument with 36 spectral bands operating in the VIS-TIR spectral range and spatial resolution varying between 250 and 1000 m at nadir. The MODIS channels centered around 11 and 12 micron have been used for the ash retrievals through the Brightness Temperature Difference algorithm and MODTRAN simulations. FALL3D is a 3-D time-dependent Eulerian model for the transport and deposition of volcanic particles that outputs, among other variables, cloud column mass and AOD. Three MODIS images collected the October 28, 29 and 30 on Mt. Etna volcano during the 2002 eruption have been considered as test cases. The results show a general good agreement between the retrieved and the modeled volcanic clouds in the first 300 km from the vents. Even if the

  2. TBIdoc: 3D content-based CT image retrieval system for traumatic brain injury

    NASA Astrophysics Data System (ADS)

    Li, Shimiao; Gong, Tianxia; Wang, Jie; Liu, Ruizhe; Tan, Chew Lim; Leong, Tze Yun; Pang, Boon Chuan; Lim, C. C. Tchoyoson; Lee, Cheng Kiang; Tian, Qi; Zhang, Zhuo

    2010-03-01

    Traumatic brain injury (TBI) is a major cause of death and disability. Computed Tomography (CT) scan is widely used in the diagnosis of TBI. Nowadays, large amount of TBI CT data is stacked in the hospital radiology department. Such data and the associated patient information contain valuable information for clinical diagnosis and outcome prediction. However, current hospital database system does not provide an efficient and intuitive tool for doctors to search out cases relevant to the current study case. In this paper, we present the TBIdoc system: a content-based image retrieval (CBIR) system which works on the TBI CT images. In this web-based system, user can query by uploading CT image slices from one study, retrieval result is a list of TBI cases ranked according to their 3D visual similarity to the query case. Specifically, cases of TBI CT images often present diffuse or focal lesions. In TBIdoc system, these pathological image features are represented as bin-based binary feature vectors. We use the Jaccard-Needham measure as the similarity measurement. Based on these, we propose a 3D similarity measure for computing the similarity score between two series of CT slices. nDCG is used to evaluate the system performance, which shows the system produces satisfactory retrieval results. The system is expected to improve the current hospital data management in TBI and to give better support for the clinical decision-making process. It may also contribute to the computer-aided education in TBI.

  3. 4D reconstruction of the past: the image retrieval and 3D model construction pipeline

    NASA Astrophysics Data System (ADS)

    Hadjiprocopis, Andreas; Ioannides, Marinos; Wenzel, Konrad; Rothermel, Mathias; Johnsons, Paul S.; Fritsch, Dieter; Doulamis, Anastasios; Protopapadakis, Eftychios; Kyriakaki, Georgia; Makantasis, Kostas; Weinlinger, Guenther; Klein, Michael; Fellner, Dieter; Stork, Andre; Santos, Pedro

    2014-08-01

    One of the main characteristics of the Internet era we are living in, is the free and online availability of a huge amount of data. This data is of varied reliability and accuracy and exists in various forms and formats. Often, it is cross-referenced and linked to other data, forming a nexus of text, images, animation and audio enabled by hypertext and, recently, by the Web3.0 standard. Our main goal is to enable historians, architects, archaeolo- gists, urban planners and affiliated professionals to reconstruct views of historical monuments from thousands of images floating around the web. This paper aims to provide an update of our progress in designing and imple- menting a pipeline for searching, filtering and retrieving photographs from Open Access Image Repositories and social media sites and using these images to build accurate 3D models of archaeological monuments as well as enriching multimedia of cultural / archaeological interest with metadata and harvesting the end products to EU- ROPEANA. We provide details of how our implemented software searches and retrieves images of archaeological sites from Flickr and Picasa repositories as well as strategies on how to filter the results, on two levels; a) based on their built-in metadata including geo-location information and b) based on image processing and clustering techniques. We also describe our implementation of a Structure from Motion pipeline designed for producing 3D models using the large collection of 2D input images (>1000) retrieved from Internet Repositories.

  4. Recognition of Simple 3D Geometrical Objects under Partial Occlusion

    NASA Astrophysics Data System (ADS)

    Barchunova, Alexandra; Sommer, Gerald

    In this paper we present a novel procedure for contour-based recognition of partially occluded three-dimensional objects. In our approach we use images of real and rendered objects whose contours have been deformed by a restricted change of the viewpoint. The preparatory part consists of contour extraction, preprocessing, local structure analysis and feature extraction. The main part deals with an extended construction and functionality of the classifier ensemble Adaptive Occlusion Classifier (AOC). It relies on a hierarchical fragmenting algorithm to perform a local structure analysis which is essential when dealing with occlusions. In the experimental part of this paper we present classification results for five classes of simple geometrical figures: prism, cylinder, half cylinder, a cube, and a bridge. We compare classification results for three classical feature extractors: Fourier descriptors, pseudo Zernike and Zernike moments.

  5. Wrapping-free phase retrieval with applications to interferometry, 3D-shape profiling, and deflectometry.

    PubMed

    Perciante, César D; Strojnik, Marija; Paez, Gonzalo; Di Martino, J Matias; Ayubi, Gastón A; Flores, Jorge L; Ferrari, José A

    2015-04-01

    Phase unwrapping is probably the most challenging step in the phase retrieval process in phase-shifting and spatial-carrier interferometry. Likewise, phase unwrapping is required in 3D-shape profiling and deflectometry. In this paper, we present a novel phase retrieval method that completely sidesteps the phase unwrapping process, significantly eliminating the guessing in phase reconstruction and thus decreasing the time data processing. The proposed wrapping-free method is based on the direct integration of the spatial derivatives of the interference patterns under the single assumption that the phase is continuous. This assumption is valid in most physical applications. Validation experiments are presented confirming the robustness of the proposed method. PMID:25967217

  6. 3D CAD model retrieval method based on hierarchical multi-features

    NASA Astrophysics Data System (ADS)

    An, Ran; Wang, Qingwen

    2015-12-01

    The classical "Shape Distribution D2" algorithm takes the distance between two random points on a surface of CAD model as statistical features, and based on that it generates a feature vector to calculate the dissimilarity and achieve the retrieval goal. This algorithm has a simple principle, high computational efficiency and can get a better retrieval results for the simple shape models. Based on the analysis of D2 algorithm's shape distribution curve, this paper enhances the algorithm's descriptive ability for a model's overall shape through the statistics of the angle between two random points' normal vectors, especially for the distinctions between the model's plane features and curved surface features; meanwhile, introduce the ratio that a line between two random points cut off by the model's surface to enhance the algorithm's descriptive ability for a model's detailed features; finally, integrating the two shape describing methods with the original D2 algorithm, this paper proposes a new method based the hierarchical multi-features. Experimental results showed that this method has bigger improvements and could get a better retrieval results compared with the traditional 3D CAD model retrieval method.

  7. Reducing Non-Uniqueness in Satellite Gravity Inversion using 3D Object Oriented Image Analysis Techniques

    NASA Astrophysics Data System (ADS)

    Fadel, I.; van der Meijde, M.; Kerle, N.

    2013-12-01

    Non-uniqueness of satellite gravity interpretation has been usually reduced by using a priori information from various sources, e.g. seismic tomography models. The reduction in non-uniqueness has been based on velocity-density conversion formulas or user interpretation for 3D subsurface structures (objects) in seismic tomography models. However, these processes introduce additional uncertainty through the conversion relations due to the dependency on the other physical parameters such as temperature and pressure, or through the bias in the interpretation due to user choices and experience. In this research, a new methodology is introduced to extract the 3D subsurface structures from 3D geophysical data using a state-of-art 3D Object Oriented Image Analysis (OOA) technique. 3D OOA is tested using a set of synthetic models that simulate the real situation in the study area of this research. Then, 3D OOA is used to extract 3D subsurface objects from a real 3D seismic tomography model. The extracted 3D objects are used to reconstruct a forward model and its response is compared with the measured satellite gravity. Finally, the result of the forward modelling, based on the extracted 3D objects, is used to constrain the inversion process of satellite gravity data. Through this work, a new object-based approach is introduced to interpret and extract the 3D subsurface objects from 3D geophysical data. This can be used to constrain modelling and inversion of potential field data using the extracted 3D subsurface structures from other methods. In summary, a new approach is introduced to constrain inversion of satellite gravity measurements and enhance interpretation capabilities.

  8. OB3D, a new set of 3D objects available for research: a web-based study

    PubMed Central

    Buffat, Stéphane; Chastres, Véronique; Bichot, Alain; Rider, Delphine; Benmussa, Frédéric; Lorenceau, Jean

    2014-01-01

    Studying object recognition is central to fundamental and clinical research on cognitive functions but suffers from the limitations of the available sets that cannot always be modified and adapted to meet the specific goals of each study. We here present a new set of 3D scans of real objects available on-line as ASCII files, OB3D. These files are lists of dots, each defined by a triplet of spatial coordinates and their normal that allow simple and highly versatile transformations and adaptations. We performed a web-based experiment to evaluate the minimal number of dots required for the denomination and categorization of these objects, thus providing a reference threshold. We further analyze several other variables derived from this data set, such as the correlations with object complexity. This new stimulus set, which was found to activate the Lower Occipital Complex (LOC) in another study, may be of interest for studies of cognitive functions in healthy participants and patients with cognitive impairments, including visual perception, language, memory, etc. PMID:25339920

  9. 3D imaging of amplitude objects embedded in phase objects using transport of intensity

    NASA Astrophysics Data System (ADS)

    Banerjee, Partha; Basunia, Mahmudunnabi

    2015-09-01

    The amplitude and phase of the complex optical field in the Helmholtz equation obey a pair of coupled equations, arising from equating the real and imaginary parts. The imaginary part yields the transport of intensity equation (TIE), which can be used to derive the phase distribution at the observation plane. If a phase object is approximately imaged on the recording plane(s), TIE yields the phase without the need for phase unwrapping. In our experiment, the 3D image of a phase object and an amplitude object embedded in a phase object is recovered. The phase object is created by heating a liquid, comprising a solution of red dye in alcohol, using a focused 514 nm laser beam to the point where self-phase modulation of the beam is observed. The optical intensities are recorded at various planes during propagation of a low power 633 nm laser beam through the liquid. In the process of applying TIE to derive the phase at the observation plane, the real part of the complex equation is also examined as a cross-check of our calculations. For pure phase objects, it is shown that the real part of the complex equation is best satisfied around the image plane. Alternatively, it is proposed that this information can be used to determine the optimum image plane.

  10. An object-oriented 3D integral data model for digital city and digital mine

    NASA Astrophysics Data System (ADS)

    Wu, Lixin; Wang, Yanbing; Che, Defu; Xu, Lei; Chen, Xuexi; Jiang, Yun; Shi, Wenzhong

    2005-10-01

    With the rapid development of urban, city space extended from surface to subsurface. As the important data source for the representation of city spatial information, 3D city spatial data have the characteristics of multi-object, heterogeneity and multi-structure. It could be classified referring to the geo-surface into three kinds: above-surface data, surface data and subsurface data. The current research on 3D city spatial information system is divided naturally into two different branch, 3D City GIS (3D CGIS) and 3D Geological Modeling (3DGM). The former emphasizes on the 3D visualization of buildings and the terrain of city, while the latter emphasizes on the visualization of geological bodies and structures. Although, it is extremely important for city planning and construction to integrate all the city spatial information including above-surface, surface and subsurface objects to conduct integral analysis and spatial manipulation. However, either 3D CGIS or 3DGM is currently difficult to realize the information integration, integral analysis and spatial manipulation. Considering 3D spatial modeling theory and methodologies, an object-oriented 3D integral spatial data model (OO3D-ISDM) is presented and software realized. The model integrates geographical objects, surface buildings and geological objects together seamlessly with TIN being its coupling interface. This paper introduced the conceptual model of OO3D-ISDM, which is comprised of 4 spatial elements, i.e. point, line, face and body, and 4 geometric primitives, i.e. vertex, segment, triangle and generalized tri-prism (GTP). The spatial model represents the geometry of surface buildings and geographical objects with triangles, and geological objects with GTP. Any of the represented objects, no mater surface buildings, terrain or subsurface objects, could be described with the basic geometry element, i.e. triangle. So the 3D spatial objects, surface buildings, terrain and geological objects can be

  11. Whole versus Part Presentations of the Interactive 3D Graphics Learning Objects

    ERIC Educational Resources Information Center

    Azmy, Nabil Gad; Ismaeel, Dina Ahmed

    2010-01-01

    The purpose of this study is to present an analysis of how the structure and design of the Interactive 3D Graphics Learning Objects can be effective and efficient in terms of Performance, Time on task, and Learning Efficiency. The study explored two treatments, namely whole versus Part Presentations of the Interactive 3D Graphics Learning Objects,…

  12. 3D object-oriented image analysis in 3D geophysical modelling: Analysing the central part of the East African Rift System

    NASA Astrophysics Data System (ADS)

    Fadel, I.; van der Meijde, M.; Kerle, N.; Lauritsen, N.

    2015-03-01

    Non-uniqueness of satellite gravity interpretation has traditionally been reduced by using a priori information from seismic tomography models. This reduction in the non-uniqueness has been based on velocity-density conversion formulas or user interpretation of the 3D subsurface structures (objects) based on the seismic tomography models and then forward modelling these objects. However, this form of object-based approach has been done without a standardized methodology on how to extract the subsurface structures from the 3D models. In this research, a 3D object-oriented image analysis (3D OOA) approach was implemented to extract the 3D subsurface structures from geophysical data. The approach was applied on a 3D shear wave seismic tomography model of the central part of the East African Rift System. Subsequently, the extracted 3D objects from the tomography model were reconstructed in the 3D interactive modelling environment IGMAS+, and their density contrast values were calculated using an object-based inversion technique to calculate the forward signal of the objects and compare it with the measured satellite gravity. Thus, a new object-based approach was implemented to interpret and extract the 3D subsurface objects from 3D geophysical data. We also introduce a new approach to constrain the interpretation of the satellite gravity measurements that can be applied using any 3D geophysical model.

  13. An Overview of 3d Topology for Ladm-Based Objects

    NASA Astrophysics Data System (ADS)

    Zulkifli, N. A.; Rahman, A. A.; van Oosterom, P.

    2015-10-01

    This paper reviews 3D topology within Land Administration Domain Model (LADM) international standard. It is important to review characteristic of the different 3D topological models and to choose the most suitable model for certain applications. The characteristic of the different 3D topological models are based on several main aspects (e.g. space or plane partition, used primitives, constructive rules, orientation and explicit or implicit relationships). The most suitable 3D topological model depends on the type of application it is used for. There is no single 3D topology model best suitable for all types of applications. Therefore, it is very important to define the requirements of the 3D topology model. The context of this paper is a 3D topology for LADM-based objects.

  14. 3D video analysis of the novel object recognition test in rats.

    PubMed

    Matsumoto, Jumpei; Uehara, Takashi; Urakawa, Susumu; Takamura, Yusaku; Sumiyoshi, Tomiki; Suzuki, Michio; Ono, Taketoshi; Nishijo, Hisao

    2014-10-01

    The novel object recognition (NOR) test has been widely used to test memory function. We developed a 3D computerized video analysis system that estimates nose contact with an object in Long Evans rats to analyze object exploration during NOR tests. The results indicate that the 3D system reproducibly and accurately scores the NOR test. Furthermore, the 3D system captures a 3D trajectory of the nose during object exploration, enabling detailed analyses of spatiotemporal patterns of object exploration. The 3D trajectory analysis revealed a specific pattern of object exploration in the sample phase of the NOR test: normal rats first explored the lower parts of objects and then gradually explored the upper parts. A systematic injection of MK-801 suppressed changes in these exploration patterns. The results, along with those of previous studies, suggest that the changes in the exploration patterns reflect neophobia to a novel object and/or changes from spatial learning to object learning. These results demonstrate that the 3D tracking system is useful not only for detailed scoring of animal behaviors but also for investigation of characteristic spatiotemporal patterns of object exploration. The system has the potential to facilitate future investigation of neural mechanisms underlying object exploration that result from dynamic and complex brain activity. PMID:24991752

  15. Temporal-spatial modeling of fast-moving and deforming 3D objects

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoliang; Wei, Youzhi

    1998-09-01

    This paper gives a brief description of the method and techniques developed for the modeling and reconstruction of fast moving and deforming 3D objects. A new approach using close-range digital terrestrial photogrammetry in conjunction with high speed photography and videography is proposed. A sequential image matching method (SIM) has been developed to automatically process pairs of images taken continuously of any fast moving and deforming 3D objects. Using the SIM technique a temporal-spatial model (TSM) of any fast moving and deforming 3D objects can be developed. The TSM would include a series of reconstructed surface models of the fast moving and deforming 3D object in the form of 3D images. The TSM allows the 3D objects to be visualized and analyzed in sequence. The SIM method, specifically the left-right matching and forward-back matching techniques are presented in the paper. An example is given which deals with the monitoring of a typical blast rock bench in a major open pit mine in Australia. With the SIM approach and the TSM model it is possible to automatically and efficiently reconstruct the 3D images of the blasting process. This reconstruction would otherwise be impossible to achieve using a labor intensive manual processing approach based on 2D images taken from conventional high speed cameras. The case study demonstrates the potential of the SIM approach and the TSM for the automatic identification, tracking and reconstruction of any fast moving and deforming 3D targets.

  16. Visual Short-Term Memory Benefit for Objects on Different 3-D Surfaces

    ERIC Educational Resources Information Center

    Xu, Yaoda; Nakayama, Ken

    2007-01-01

    Visual short-term memory (VSTM) plays an important role in visual cognition. Although objects are located on different 3-dimensional (3-D) surfaces in the real world, how VSTM capacity may be influenced by the presence of multiple 3-D surfaces has never been examined. By manipulating binocular disparities of visual displays, the authors found that…

  17. GestAction3D: A Platform for Studying Displacements and Deformations of 3D Objects Using Hands

    NASA Astrophysics Data System (ADS)

    Lingrand, Diane; Renevier, Philippe; Pinna-Déry, Anne-Marie; Cremaschi, Xavier; Lion, Stevens; Rouel, Jean-Guilhem; Jeanne, David; Cuisinaud, Philippe; Soula*, Julien

    We present a low-cost hand-based device coupled with a 3D motion recovery engine and 3D visualization. This platform aims at studying ergonomic 3D interactions in order to manipulate and deform 3D models by interacting with hands on 3D meshes. Deformations are done using different modes of interaction that we will detail in the paper. Finger extremities are attached to vertices, edges or facets. Switching from one mode to another or changing the point of view is done using gestures. The determination of the more adequate gestures is part of the work

  18. Electro-holography display using computer generated hologram of 3D objects based on projection spectra

    NASA Astrophysics Data System (ADS)

    Huang, Sujuan; Wang, Duocheng; He, Chao

    2012-11-01

    A new method of synthesizing computer-generated hologram of three-dimensional (3D) objects is proposed from their projection images. A series of projection images of 3D objects are recorded with one-dimensional azimuth scanning. According to the principles of paraboloid of revolution in 3D Fourier space and 3D central slice theorem, spectra information of 3D objects can be gathered from their projection images. Considering quantization error of horizontal and vertical directions, the spectrum information from each projection image is efficiently extracted in double circle and four circles shape, to enhance the utilization of projection spectra. Then spectra information of 3D objects from all projection images is encoded into computer-generated hologram based on Fourier transform using conjugate-symmetric extension. The hologram includes 3D information of objects. Experimental results for numerical reconstruction of the CGH at different distance validate the proposed methods and show its good performance. Electro-holographic reconstruction can be realized by using an electronic addressing reflective liquid-crystal display (LCD) spatial light modulator. The CGH from the computer is loaded onto the LCD. By illuminating a reference light from a laser source to the LCD, the amplitude and phase information included in the CGH will be reconstructed due to the diffraction of the light modulated by the LCD.

  19. Representing 3D virtual objects: interaction between visuo-spatial ability and type of exploration.

    PubMed

    Meijer, Frank; van den Broek, Egon L

    2010-03-17

    We investigated individual differences in interactively exploring 3D virtual objects. 36 participants explored 24 simple and 24 difficult objects (composed of respectively three and five Biederman geons) actively, passively, or not at all. Both their 3D mental representation of the objects and visuo-spatial ability was assessed. Results show that, regardless of the object's complexity, people with a low VSA benefit from active exploration of objects, where people with a middle or high VSA do not. These findings extend and refine earlier research on interactively learning visuo-spatial information and underline the importance to take individual differences into account. PMID:20116394

  20. Development of goniophotometric imaging system for recording reflectance spectra of 3D objects

    NASA Astrophysics Data System (ADS)

    Tonsho, Kazutaka; Akao, Y.; Tsumura, Norimichi; Miyake, Yoichi

    2001-12-01

    In recent years, it is required to develop a system for 3D capture of archives in museums and galleries. In visualizing of 3D object, it is important to reproduce both color and glossiness accurately. Our final goal is to construct digital archival systems in museum and internet or virtual museum via World Wide Web. To achieve our goal, we have developed gonio-photometric imaging system by using high accurate multi-spectral camera and 3D digitizer. In this paper, gonio-photometric imaging method is introduced for recording 3D object. 5-bands images of the object are taken under 7 different illuminants angles. The 5-band image sequences are then analyzed on the basis of both dichromatic reflection model and Phong model to extract gonio-photometric property of the object. The images of the 3D object under illuminants with arbitrary spectral radiant distribution, illuminating angles, and visual points are rendered by using OpenGL with the 3D shape and gonio-photometric property.

  1. Computing 3-D structure of rigid objects using stereo and motion

    NASA Technical Reports Server (NTRS)

    Nguyen, Thinh V.

    1987-01-01

    Work performed as a step toward an intelligent automatic machine vision system for 3-D imaging is discussed. The problem considered is the quantitative 3-D reconstruction of rigid objects. Motion and stereo are the two clues considered in this system. The system basically consists of three processes: the low level process to extract image features, the middle level process to establish the correspondence in the stereo (spatial) and motion (temporal) modalities, and the high level process to compute the 3-D coordinates of the corner points by integrating the spatial and temporal correspondences.

  2. Phase-retrieved optical projection tomography for 3D imaging through scattering layers

    NASA Astrophysics Data System (ADS)

    Ancora, Daniele; Di Battista, Diego; Giasafaki, Georgia; Psycharakis, Stylianos; Liapis, Evangelos; Zacharopoulos, Athanasios; Zacharakis, Giannis

    2016-03-01

    Recently great progress has been made in biological and biomedical imaging by combining non-invasive optical methods, novel adaptive light manipulation and computational techniques for intensity-based phase recovery and three dimensional image reconstruction. In particular and in relation to the work presented here, Optical Projection Tomography (OPT) is a well-established technique for imaging mostly transparent absorbing biological models such as C. Elegans and Danio Rerio. On the contrary, scattering layers like the cocoon surrounding the Drosophila during the pupae stage constitutes a challenge for three dimensional imaging through such a complex structure. However, recent studies enabled image reconstruction through scattering curtains up to few transport mean free paths via phase retrieval iterative algorithms allowing to uncover objects hidden behind complex layers. By combining these two techniques we explore the possibility to perform a three dimensional image reconstruction of fluorescent objects embedded between scattering layers without compromising its structural integrity. Dynamical cross correlation registration was implemented for the registration process due to translational and flipping ambiguity of the phase retrieval problem, in order to provide the correct aligned set of data to perform the back-projection reconstruction. We have thus managed to reconstruct a hidden complex object between static scattering curtains and compared with the effective reconstruction to fully understand the process before the in-vivo biological implementation.

  3. 3D photography in the objective analysis of volume augmentation including fat augmentation and dermal fillers.

    PubMed

    Meier, Jason D; Glasgold, Robert A; Glasgold, Mark J

    2011-11-01

    The authors present quantitative and objective 3D data from their studies showing long-term results with facial volume augmentation. The first study analyzes fat grafting of the midface and the second study presents augmentation of the tear trough with hyaluronic filler. Surgeons using 3D quantitative analysis can learn the duration of results and the optimal amount to inject, as well as showing patients results that are not demonstrable with standard, 2D photography. PMID:22004863

  4. 2D virtual texture on 3D real object with coded structured light

    NASA Astrophysics Data System (ADS)

    Molinier, Thierry; Fofi, David; Salvi, Joaquim; Gorria, Patrick

    2008-02-01

    Augmented reality is used to improve color segmentation on human body or on precious no touch artifacts. We propose a technique to project a synthesized texture on real object without contact. Our technique can be used in medical or archaeological application. By projecting a suitable set of light patterns onto the surface of a 3D real object and by capturing images with a camera, a large number of correspondences can be found and the 3D points can be reconstructed. We aim to determine these points of correspondence between cameras and projector from a scene without explicit points and normals. We then project an adjusted texture onto the real object surface. We propose a global and automatic method to virtually texture a 3D real object.

  5. Gonio photometric imaging for recording of reflectance spectra of 3D objects

    NASA Astrophysics Data System (ADS)

    Miyake, Yoichi; Tsumura, Norimichi; Haneishi, Hideaki; Hayashi, Junichiro

    2002-06-01

    In recent years, it is required to develop a system for 3D capture of archives in museums and galleries. In visualizing of 3D object, it is important to reproduce both color and glossiness accurately. Our final goal is to construct digital archival systems in museum and Internet or virtual museum via World Wide Web. To archive our goal, we have developed the multi-spectral imaging systems to record and estimate reflectance spectra of the art paints based on principal component analysis and Wiener estimation method. In this paper, Gonio photometric imaging method is introduced for recording of 3D object. Five-band images of the object are taken under seven different illuminants angles. The set of five-band images are then analyzed on the basis of both dichromatic reflection model and Phong model to extract Gonio photometric information of the object. Prediction of reproduced images of the object under several illuminants and illumination angles is demonstrated and images that are synthesized with 3D wire frame image taken by 3D digitizer are also presented.

  6. Multiple capture locations for 3D ultrasound-guided robotic retrieval of moving bodies from a beating heart

    NASA Astrophysics Data System (ADS)

    Thienphrapa, Paul; Ramachandran, Bharat; Elhawary, Haytham; Taylor, Russell H.; Popovic, Aleksandra

    2012-02-01

    Free moving bodies in the heart pose a serious health risk as they may be released in the arteries causing blood flow disruption. These bodies may be the result of various medical conditions and trauma. The conventional approach to removing these objects involves open surgery with sternotomy, the use of cardiopulmonary bypass, and a wide resection of the heart muscle. We advocate a minimally invasive surgical approach using a flexible robotic end effector guided by 3D transesophageal echocardiography. In a phantom study, we track a moving body in a beating heart using a modified normalized cross-correlation method, with mean RMS errors of 2.3 mm. We previously found the foreign body motion to be fast and abrupt, rendering infeasible a retrieval method based on direct tracking. We proposed a strategy based on guiding a robot to the most spatially probable location of the fragment and securing it upon its reentry to said location. To improve efficacy in the context of a robotic retrieval system, we extend this approach by exploring multiple candidate capture locations. Salient locations are identified based on spatial probability, dwell time, and visit frequency; secondary locations are also examined. Aggregate results indicate that the location of highest spatial probability (50% occupancy) is distinct from the longest-dwelled location (0.84 seconds). Such metrics are vital in informing the design of a retrieval system and capture strategies, and they can be computed intraoperatively to select the best capture location based on constraints such as workspace, time, and device manipulability. Given the complex nature of fragment motion, the ability to analyze multiple capture locations is a desirable capability in an interventional system.

  7. Computer generated holograms of 3D objects with reduced number of projections

    NASA Astrophysics Data System (ADS)

    Huang, Su-juan; Liu, Dao-jin; Zhao, Jing-jing

    2010-11-01

    A new method for synthesizing computer-generated holograms of 3D objects has been proposed with reduced number of projections. According to the principles of paraboloid of revolution in 3D Fourier space, spectra information of 3D objects is gathered from projection images. We record a series of real projection images of 3D objects under incoherent white-light illumination by circular scanning method, and synthesize interpolated projection images by motion estimation and compensation between adjacent real projection images, then extract the spectra information of the 3D objects from all projection images in circle form. Because of quantization error, information extraction in two circles form is better than in single circle. Finally hologram is encoded based on computer-generated holography using a conjugate-symmetric extension. Our method significantly reduces the number of required real projections without increasing much of the computing time of the hologram and degrading the reconstructed image. Numerical reconstruction of the hologram shows good results.

  8. Generation of geometric representations of 3D objects in CAD/CAM by digital photogrammetry

    NASA Astrophysics Data System (ADS)

    Li, Rongxing

    This paper presents a method for the generation of geometric representations of 3D objects by digital photogrammetry. In CAD/CAM systems geometric modelers are usually used to create three-dimensional (3D) geometric representations for design and manufacturing purposes. However, in cases where geometric information such as dimensions and shapes of objects are not available, measurements of physically existing objects become necessary. In this paper, geometric parameters of primitives of 3D geometric representations such as Boundary Representation (B-rep), Constructive Solid Geometry (CSG), and digital surface models are determined by digital image matching techniques. An algorithm for reconstruction of surfaces with discontinuities is developed. Interfaces between digital photogrammetric data and these geometric representations are realized. This method can be applied to design and manufacturing in mechanical engineering, automobile industry, robot technology, spatial information systems and others.

  9. High-purity 3D nano-objects grown by focused-electron-beam induced deposition.

    PubMed

    Córdoba, Rosa; Sharma, Nidhi; Kölling, Sebastian; Koenraad, Paul M; Koopmans, Bert

    2016-09-01

    To increase the efficiency of current electronics, a specific challenge for the next generation of memory, sensing and logic devices is to find suitable strategies to move from two- to three-dimensional (3D) architectures. However, the creation of real 3D nano-objects is not trivial. Emerging non-conventional nanofabrication tools are required for this purpose. One attractive method is focused-electron-beam induced deposition (FEBID), a direct-write process of 3D nano-objects. Here, we grow 3D iron and cobalt nanopillars by FEBID using diiron nonacarbonyl Fe2(CO)9, and dicobalt octacarbonyl Co2(CO)8, respectively, as starting materials. In addition, we systematically study the composition of these nanopillars at the sub-nanometer scale by atom probe tomography, explicitly mapping the homogeneity of the radial and longitudinal composition distributions. We show a way of fabricating high-purity 3D vertical nanostructures of ∼50 nm in diameter and a few micrometers in length. Our results suggest that the purity of such 3D nanoelements (above 90 at% Fe and above 95 at% Co) is directly linked to their growth regime, in which the selected deposition conditions are crucial for the final quality of the nanostructure. Moreover, we demonstrate that FEBID and the proposed characterization technique not only allow for growth and chemical analysis of single-element structures, but also offers a new way to directly study 3D core-shell architectures. This straightforward concept could establish a promising route to the design of 3D elements for future nano-electronic devices. PMID:27454835

  10. High-purity 3D nano-objects grown by focused-electron-beam induced deposition

    NASA Astrophysics Data System (ADS)

    Córdoba, Rosa; Sharma, Nidhi; Kölling, Sebastian; Koenraad, Paul M.; Koopmans, Bert

    2016-09-01

    To increase the efficiency of current electronics, a specific challenge for the next generation of memory, sensing and logic devices is to find suitable strategies to move from two- to three-dimensional (3D) architectures. However, the creation of real 3D nano-objects is not trivial. Emerging non-conventional nanofabrication tools are required for this purpose. One attractive method is focused-electron-beam induced deposition (FEBID), a direct-write process of 3D nano-objects. Here, we grow 3D iron and cobalt nanopillars by FEBID using diiron nonacarbonyl Fe2(CO)9, and dicobalt octacarbonyl Co2(CO)8, respectively, as starting materials. In addition, we systematically study the composition of these nanopillars at the sub-nanometer scale by atom probe tomography, explicitly mapping the homogeneity of the radial and longitudinal composition distributions. We show a way of fabricating high-purity 3D vertical nanostructures of ∼50 nm in diameter and a few micrometers in length. Our results suggest that the purity of such 3D nanoelements (above 90 at% Fe and above 95 at% Co) is directly linked to their growth regime, in which the selected deposition conditions are crucial for the final quality of the nanostructure. Moreover, we demonstrate that FEBID and the proposed characterization technique not only allow for growth and chemical analysis of single-element structures, but also offers a new way to directly study 3D core–shell architectures. This straightforward concept could establish a promising route to the design of 3D elements for future nano-electronic devices.

  11. Automatic 360-deg profilometry of a 3D object using a shearing interferometer and virtual grating

    NASA Astrophysics Data System (ADS)

    Zhang, Yong-Lin; Bu, Guixue

    1996-10-01

    Phase measuring technique has been widely used in optical precision inspection for its extraordinary advantage. We use the phase-measuring technique and design a practical instrument for measuring 360 degrees profile of 3D object. A novel method that can realize profile detection with higher speed and lower cost is proposed. Phase unwrapping algorithm based on the second order differentiation is developed. A complete 3D shape is reconstructed from a series of line- section profiles corresponding to discrete angular position of the object. The profile-jointing procedure is only related with two fixed parameters and coordination transformation.

  12. 3D-Web-GIS RFID Location Sensing System for Construction Objects

    PubMed Central

    2013-01-01

    Construction site managers could benefit from being able to visualize on-site construction objects. Radio frequency identification (RFID) technology has been shown to improve the efficiency of construction object management. The objective of this study is to develop a 3D-Web-GIS RFID location sensing system for construction objects. An RFID 3D location sensing algorithm combining Simulated Annealing (SA) and a gradient descent method is proposed to determine target object location. In the algorithm, SA is used to stabilize the search process and the gradient descent method is used to reduce errors. The locations of the analyzed objects are visualized using the 3D-Web-GIS system. A real construction site is used to validate the applicability of the proposed method, with results indicating that the proposed approach can provide faster, more accurate, and more stable 3D positioning results than other location sensing algorithms. The proposed system allows construction managers to better understand worksite status, thus enhancing managerial efficiency. PMID:23864821

  13. Detection, segmentation and classification of 3D urban objects using mathematical morphology and supervised learning

    NASA Astrophysics Data System (ADS)

    Serna, Andrés; Marcotegui, Beatriz

    2014-07-01

    We propose an automatic and robust approach to detect, segment and classify urban objects from 3D point clouds. Processing is carried out using elevation images and the result is reprojected onto the 3D point cloud. First, the ground is segmented and objects are detected as discontinuities on the ground. Then, connected objects are segmented using a watershed approach. Finally, objects are classified using SVM with geometrical and contextual features. Our methodology is evaluated on databases from Ohio (USA) and Paris (France). In the former, our method detects 98% of the objects, 78% of them are correctly segmented and 82% of the well-segmented objects are correctly classified. In the latter, our method leads to an improvement of about 15% on the classification step with respect to previous works. Quantitative results prove that our method not only provides a good performance but is also faster than other works reported in the literature.

  14. 3D shape shearography with integrated structured light projection for strain inspection of curved objects

    NASA Astrophysics Data System (ADS)

    Anisimov, Andrei G.; Groves, Roger M.

    2015-05-01

    Shearography (speckle pattern shearing interferometry) is a non-destructive testing technique that provides full-field surface strain characterization. Although real-life objects especially in aerospace, transport or cultural heritage are not flat (e.g. aircraft leading edges or sculptures), their inspection with shearography is of interest for both hidden defect detection and material characterization. Accurate strain measuring of a highly curved or free form surface needs to be performed by combining inline object shape measuring and processing of shearography data in 3D. Previous research has not provided a general solution. This research is devoted to the practical questions of 3D shape shearography system development for surface strain characterization of curved objects. The complete procedure of calibration and data processing of a 3D shape shearography system with integrated structured light projector is presented. This includes an estimation of the actual shear distance and a sensitivity matrix correction within the system field of view. For the experimental part a 3D shape shearography system prototype was developed. It employs three spatially-distributed shearing cameras, with Michelson interferometers acting as the shearing devices, one illumination laser source and a structured light projector. The developed system performance was evaluated with a previously reported cylinder specimen (length 400 mm, external diameter 190 mmm) loaded by internal pressure. Further steps for the 3D shape shearography prototype and the technique development are also proposed.

  15. Multiple Object Retrieval in Image Databases Using Hierarchical Segmentation Tree

    ERIC Educational Resources Information Center

    Chen, Wei-Bang

    2012-01-01

    The purpose of this research is to develop a new visual information analysis, representation, and retrieval framework for automatic discovery of salient objects of user's interest in large-scale image databases. In particular, this dissertation describes a content-based image retrieval framework which supports multiple-object retrieval. The…

  16. Holographic display of real existing objects from their 3D Fourier spectrum

    NASA Astrophysics Data System (ADS)

    Yatagai, Toyohiko; Sando, Yusuke

    2005-02-01

    A method for synthesizing computer-generated holograms of real-existing objects is described. A series of projection images are recorded both vertically and horizontally with an incoherent light source and a color CCD camera. According to the principle of computer tomography(CT), the 3-D Fourier spectrum is calculated from several projection images of objects and the Fresnel computer-generated hologram(CGH) is synthesized using a part of the 3-D Fourier spectrum. This method has following advantages. At first, no-blur reconstructed images in any direction are obtained owing to two-dimensionally scanning in recording. Secondarily, since not interference fringes but simple projection images of objects are recorded, a coherent light source is not necessary for recording. The use of a color CCD in recording enables us to record and reconstruct colorful objects. Finally, we demonstrate color reconstruction of objects both numerically and optically.

  17. A Skeleton-Based 3D Shape Reconstruction of Free-Form Objects with Stereo Vision

    NASA Astrophysics Data System (ADS)

    Saini, Deepika; Kumar, Sanjeev

    2015-12-01

    In this paper, an efficient approach is proposed for recovering the 3D shape of a free-form object from its arbitrary pair of stereo images. In particular, the reconstruction problem is treated as the reconstruction of the skeleton and the external boundary of the object. The reconstructed skeleton is termed as the line-like representation or curve-skeleton of the 3D object. The proposed solution for object reconstruction is based on this evolved curve-skeleton. It is used as a seed for recovering shape of the 3D object, and the extracted boundary is used for terminating the growing process of the object. NURBS-skeleton is used to extract the skeleton of both views. Affine invariant property of the convex hulls is used to establish the correspondence between the skeletons and boundaries in the stereo images. In the growing process, a distance field is defined for each skeleton point as the smallest distance from that point to the boundary of the object. A sphere centered at a skeleton point of radius equal to the minimum distance to the boundary is tangential to the boundary. Filling in the spheres centered at each skeleton point reconstructs the object. Several results are presented in order to check the applicability and validity of the proposed algorithm.

  18. Recognition by Humans and Pigeons of Novel Views of 3-D Objects and Their Photographs

    ERIC Educational Resources Information Center

    Friedman, Alinda; Spetch, Marcia L.; Ferrey, Anne

    2005-01-01

    Humans and pigeons were trained to discriminate between 2 views of actual 3-D objects or their photographs. They were tested on novel views that were either within the closest rotational distance between the training views (interpolated) or outside of that range (extrapolated). When training views were 60? apart, pigeons, but not humans,…

  19. Modeling and modification of medical 3D objects. The benefit of using a haptic modeling tool.

    PubMed

    Kling-Petersen, T; Rydmark, M

    2000-01-01

    any given amount of smoothing to the object. While the final objects need to be exported for further 3D graphic manipulation, FreeForm addresses one of the most time consuming problems of 3D modeling: modification and creation of non-geometric 3D objects. PMID:10977532

  20. Retrieval of Vegetation Structural Parameters and 3-D Reconstruction of Forest Canopies Using Ground-Based Echidna® Lidar

    NASA Astrophysics Data System (ADS)

    Strahler, A. H.; Yao, T.; Zhao, F.; Yang, X.; Schaaf, C.; Woodcock, C. E.; Jupp, D. L.; Culvenor, D.; Newnham, G.; Lovell, J.

    2010-12-01

    A ground-based, scanning, near-infrared lidar, the Echidna® validation instrument (EVI), built by CSIRO Australia, retrieves structural parameters of forest stands rapidly and accurately, and by merging multiple scans into a single point cloud, the lidar also provides 3-D stand reconstructions. Echidna lidar technology scans with pulses of light at 1064 nm wavelength and digitizes the full return waveform sufficiently finely to recover and distinguish the differing shapes of return pulses as they are scattered by leaves, trunks, and branches. Deployments in New England in 2007 and the southern Sierra Nevada of California in 2008 tested the ability of the instrument to retrieve mean tree diameter, stem count density (stems/ha), basal area, and above-ground woody biomass from single scans at points beneath the forest canopy. Parameters retrieved from five scans located within six 1-ha stand sites matched manually-measured parameters with values of R2 = 0.94-0.99 in New England and 0.92-0.95 in the Sierra Nevada. Retrieved leaf area index (LAI) values were similar to those of LAI-2000 and hemispherical photography. In New England, an analysis of variance showed that EVI-retrieved values were not significantly different from other methods (power = 0.84 or higher). In the Sierra, R2 = 0.96 and 0.81 for hemispherical photos and LAI-2000, respectively. Foliage profiles, which measure leaf area with canopy height, showed distinctly different shapes for the stands, depending on species composition and age structure. New England stand heights, obtained from foliage profiles, were not significantly different (power = 0.91) from RH100 values observed by LVIS in 2003. Three-dimensional stand reconstruction identifies one or more “hits” along the pulse path coupled with the peak return of each hit expressed as apparent reflectance. Returns are classified as trunk, leaf, or ground returns based on the shape of the return pulse and its location. These data provide a point

  1. Fast error simulation of optical 3D measurements at translucent objects

    NASA Astrophysics Data System (ADS)

    Lutzke, P.; Kühmstedt, P.; Notni, G.

    2012-09-01

    The scan results of optical 3D measurements at translucent objects deviate from the real objects surface. This error is caused by the fact that light is scattered in the objects volume and is not exclusively reflected at its surface. A few approaches were made to separate the surface reflected light from the volume scattered. For smooth objects the surface reflected light is dominantly concentrated in specular direction and could only be observed from a point in this direction. Thus the separation either leads to measurement results only creating data for near specular directions or provides data from not well separated areas. To ensure the flexibility and precision of optical 3D measurement systems for translucent materials it is necessary to enhance the understanding of the error forming process. For this purpose a technique for simulating the 3D measurement at translucent objects is presented. A simple error model is shortly outlined and extended to an efficient simulation environment based upon ordinary raytracing methods. In comparison the results of a Monte-Carlo simulation are presented. Only a few material and object parameters are needed for the raytracing simulation approach. The attempt of in-system collection of these material and object specific parameters is illustrated. The main concept of developing an error-compensation method based on the simulation environment and the collected parameters is described. The complete procedure is using both, the surface reflected and the volume scattered light for further processing.

  2. Identification and Detection of Simple 3D Objects with Severely Blurred Vision

    PubMed Central

    Kallie, Christopher S.; Legge, Gordon E.; Yu, Deyue

    2012-01-01

    Purpose. Detecting and recognizing three-dimensional (3D) objects is an important component of the visual accessibility of public spaces for people with impaired vision. The present study investigated the impact of environmental factors and object properties on the recognition of objects by subjects who viewed physical objects with severely reduced acuity. Methods. The experiment was conducted in an indoor testing space. We examined detection and identification of simple convex objects by normally sighted subjects wearing diffusing goggles that reduced effective acuity to 20/900. We used psychophysical methods to examine the effect on performance of important environmental variables: viewing distance (from 10–24 feet, or 3.05–7.32 m) and illumination (overhead fluorescent and artificial window), and object variables: shape (boxes and cylinders), size (heights from 2–6 feet, or 0.61–1.83 m), and color (gray and white). Results. Object identification was significantly affected by distance, color, height, and shape, as well as interactions between illumination, color, and shape. A stepwise regression analysis showed that 64% of the variability in identification could be explained by object contrast values (58%) and object visual angle (6%). Conclusions. When acuity is severely limited, illumination, distance, color, height, and shape influence the identification and detection of simple 3D objects. These effects can be explained in large part by the impact of these variables on object contrast and visual angle. Basic design principles for improving object visibility are discussed. PMID:23111613

  3. Printing of metallic 3D micro-objects by laser induced forward transfer.

    PubMed

    Zenou, Michael; Kotler, Zvi

    2016-01-25

    Digital printing of 3D metal micro-structures by laser induced forward transfer under ambient conditions is reviewed. Recent progress has allowed drop on demand transfer of molten, femto-liter, metal droplets with a high jetting directionality. Such small volume droplets solidify instantly, on a nanosecond time scale, as they touch the substrate. This fast solidification limits their lateral spreading and allows the fabrication of high aspect ratio and complex 3D metal structures. Several examples of micron-scale resolution metal objects printed using this method are presented and discussed. PMID:26832524

  4. Close-Range Photogrammetric Tools for Small 3d Archeological Objects

    NASA Astrophysics Data System (ADS)

    Samaan, M.; Héno, R.; Pierrot-Deseilligny, M.

    2013-07-01

    This article will focus on the first experiments carried out for our PHD thesis, which is meant to make the new image-based methods available for archeologists. As a matter of fact, efforts need to be made to find cheap, efficient and user-friendly procedures for image acquisition, data processing and quality control. Among the numerous tasks that archeologists have to face daily is the 3D recording of very small objects. The Apero/MicMac tools were used for the georeferencing and the dense correlation procedures. Relatively standard workflows lead to depth maps, which can be represented either as 3D point clouds or shaded relief images.

  5. The Visual Representation of 3D Object Orientation in Parietal Cortex

    PubMed Central

    Cowan, Noah J.; Angelaki, Dora E.

    2013-01-01

    An accurate representation of three-dimensional (3D) object orientation is essential for interacting with the environment. Where and how the brain visually encodes 3D object orientation remains unknown, but prior studies suggest the caudal intraparietal area (CIP) may be involved. Here, we develop rigorous analytical methods for quantifying 3D orientation tuning curves, and use these tools to the study the neural coding of surface orientation. Specifically, we show that single neurons in area CIP of the rhesus macaque jointly encode the slant and tilt of a planar surface, and that across the population, the distribution of preferred slant-tilts is not statistically different from uniform. This suggests that all slant-tilt combinations are equally represented in area CIP. Furthermore, some CIP neurons are found to also represent the third rotational degree of freedom that determines the orientation of the image pattern on the planar surface. Together, the present results suggest that CIP is a critical neural locus for the encoding of all three rotational degrees of freedom specifying an object's 3D spatial orientation. PMID:24305830

  6. Acquiring 3-D information about thick objects from differential interference contrast images using texture extraction

    NASA Astrophysics Data System (ADS)

    Sierra, Heidy; Brooks, Dana; Dimarzio, Charles

    2010-07-01

    The extraction of 3-D morphological information about thick objects is explored in this work. We extract this information from 3-D differential interference contrast (DIC) images by applying a texture detection method. Texture extraction methods have been successfully used in different applications to study biological samples. A 3-D texture image is obtained by applying a local entropy-based texture extraction method. The use of this method to detect regions of blastocyst mouse embryos that are used in assisted reproduction techniques such as in vitro fertilization is presented as an example. Results demonstrate the potential of using texture detection methods to improve morphological analysis of thick samples, which is relevant to many biomedical and biological studies. Fluorescence and optical quadrature microscope phase images are used for validation.

  7. Systems in Development: Motor Skill Acquisition Facilitates 3D Object Completion

    PubMed Central

    Soska, Kasey C.; Adolph, Karen E.; Johnson, Scott P.

    2009-01-01

    How do infants learn to perceive the backs of objects that they see only from a limited viewpoint? Infants’ 3D object completion abilities emerge in conjunction with developing motor skills—independent sitting and visual-manual exploration. Twenty-eight 4.5- to 7.5-month-old infants were habituated to a limited-view object and tested with volumetrically complete and incomplete (hollow) versions of the same object. Parents reported infants’ sitting experience, and infants’ visual-manual exploration of objects was observed in a structured play session. Infants’ self-sitting experience and visual-manual exploratory skills predicted looking to the novel, incomplete object on the habituation task. Further analyses revealed that self-sitting facilitated infants’ visual inspection of objects while they manipulated them. The results are framed within a developmental systems approach, wherein infants’ sitting skill, multimodal object exploration, and object knowledge are linked in developmental time. PMID:20053012

  8. CAD/CAM/CAE representation of 3D objects measured by fringe projection

    NASA Astrophysics Data System (ADS)

    Pancewicz, Tomasz; Kujawinska, Malgorzata

    1998-07-01

    In the paper the creation of a virtual object on the base of optical measurement of 3D object by fringe projection technique coupled with the capabilities of CAD systems is presented. Basic stages of that task, being the most important part of the reverse engineering process, are discussed and the procedure is formulated by terms and definitions of theory of optimal algorithms. The quality criteria of a virtual object are defined and the influence of consecutive stages of the task on the quality of the virtual object is discussed.

  9. A Novel Medical Freehand Sketch 3D Model Retrieval Method by Dimensionality Reduction and Feature Vector Transformation

    PubMed Central

    Jing, Zhang; Sheng, Kang Bao

    2016-01-01

    To assist physicians to quickly find the required 3D model from the mass medical model, we propose a novel retrieval method, called DRFVT, which combines the characteristics of dimensionality reduction (DR) and feature vector transformation (FVT) method. The DR method reduces the dimensionality of feature vector; only the top M low frequency Discrete Fourier Transform coefficients are retained. The FVT method does the transformation of the original feature vector and generates a new feature vector to solve the problem of noise sensitivity. The experiment results demonstrate that the DRFVT method achieves more effective and efficient retrieval results than other proposed methods. PMID:27293478

  10. The effect of background and illumination on color identification of real, 3D objects

    PubMed Central

    Allred, Sarah R.; Olkkonen, Maria

    2013-01-01

    For the surface reflectance of an object to be a useful cue to object identity, judgments of its color should remain stable across changes in the object's environment. In 2D scenes, there is general consensus that color judgments are much more stable across illumination changes than background changes. Here we investigate whether these findings generalize to real 3D objects. Observers made color matches to cubes as we independently varied both the illumination impinging on the cube and the 3D background of the cube. As in 2D scenes, we found relatively high but imperfect stability of color judgments under an illuminant shift. In contrast to 2D scenes, we found that background had little effect on average color judgments. In addition, variability of color judgments was increased by an illuminant shift and decreased by embedding the cube within a background. Taken together, these results suggest that in real 3D scenes with ample cues to object segregation, the addition of a background may improve stability of color identification. PMID:24273521

  11. Neural network techniques for invariant recognition and motion tracking of 3-D objects

    SciTech Connect

    Hwang, J.N.; Tseng, Y.H.

    1995-12-31

    Invariant recognition and motion tracking of 3-D objects under partial object viewing are difficult tasks. In this paper, we introduce a new neural network solution that is robust to noise corruption and partial viewing of objects. This method directly utilizes the acquired range data and requires no feature extraction. In the proposed approach, the object is first parametrically represented by a continuous distance transformation neural network (CDTNN) which is trained by the surface points of the exemplar object. When later presented with the surface points of an unknown object, this parametric representation allows the mismatch information to back-propagate through the CDTNN to gradually determine the best similarity transformation (translation and rotation) of the unknown object. The mismatch can be directly measured in the reconstructed representation domain between the model and the unknown object.

  12. a Low-Cost and Portable System for 3d Reconstruction of Texture-Less Objects

    NASA Astrophysics Data System (ADS)

    Hosseininaveh, A.; Yazdan, R.; Karami, A.; Moradi, M.; Ghorbani, F.

    2015-12-01

    The optical methods for 3D modelling of objects can be classified into two categories including image-based and range-based methods. Structure from Motion is one of the image-based methods implemented in commercial software. In this paper, a low-cost and portable system for 3D modelling of texture-less objects is proposed. This system includes a rotating table designed and developed by using a stepper motor and a very light rotation plate. The system also has eight laser light sources with very dense and strong beams which provide a relatively appropriate pattern on texture-less objects. In this system, regarding to the step of stepper motor, images are semi automatically taken by a camera. The images can be used in structure from motion procedures implemented in Agisoft software.To evaluate the performance of the system, two dark objects were used. The point clouds of these objects were obtained by spraying a light powders on the objects and exploiting a GOM laser scanner. Then these objects were placed on the proposed turntable. Several convergent images were taken from each object while the laser light sources were projecting the pattern on the objects. Afterward, the images were imported in VisualSFM as a fully automatic software package for generating an accurate and complete point cloud. Finally, the obtained point clouds were compared to the point clouds generated by the GOM laser scanner. The results showed the ability of the proposed system to produce a complete 3D model from texture-less objects.

  13. Hybrid system of optics and computer for 3-D object recognition

    NASA Astrophysics Data System (ADS)

    Li, Qun Z.; Miao, Peng C.; He, Anzhi

    1992-03-01

    In this paper, a hybrid system of optics and computer for 3D object recognition is presented. The system consists of a Twyman-Green interferometer, a He-Ne laser, a computer, a TV camera, and an image processor. The structured light produced by a Twyman-Green interferometer is split in and illuminates objects in two directions at the same time. Moire contour is formed on the surface of object. In order to delete unwanted patterns in moire contour, we don't utilize the moire contour on the surface of object. We place a TV camera in the middle of the angle between two illuminating directions and take two groups of deformed fringes on the surface of objects. Two groups of deformed fringes are processed using the digital image processing system controlled and operated by XOR logic in the computer, moire fringes are then extracted from the complicated environment. 3D coordinates of points of the object are obtained after moire fringe is followed, and points belonging to the same fringe are given the same altitude. The object is described by its projected drawings in three coordinate planes. The projected drawings in three coordinate planes of the known objects are stored in the library of judgment. The object can be recognized by inquiring the library of judgment.

  14. A 3-D tomographic retrieval approach with advection compensation for the air-borne limb-imager GLORIA

    NASA Astrophysics Data System (ADS)

    Ungermann, J.; Blank, J.; Lotz, J.; Leppkes, K.; Hoffmann, L.; Guggenmoser, T.; Kaufmann, M.; Preusse, P.; Naumann, U.; Riese, M.

    2011-11-01

    Infrared limb sounding from aircraft can provide 2-D curtains of multiple trace gas species. However, conventional limb sounders view perpendicular to the aircraft axis and are unable to resolve the observed airmass along their line-of-sight. GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) is a new remote sensing instrument that is able to adjust its horizontal view angle with respect to the aircraft flight direction from 45° to 135°. This will allow for tomographic measurements of mesoscale structures for a wide variety of atmospheric constituents. Many flights of the GLORIA instrument will not follow closed curves that allow measuring an airmass from all directions. Consequently, it is examined by means of simulations, what spatial resolution can be expected under ideal conditions from tomographic evaluation of measurements made during a straight flight. It is demonstrated that the achievable horizontal resolution in the line-of-sight direction could be reduced from over 200 km to around 70 km compared to conventional retrievals and that the tomographic retrieval is also more robust against horizontal gradients in retrieved quantities in this direction. In a second step, it is shown that the incorporation of channels exhibiting different optical depth can further enhance the spatial resolution of 3-D retrievals enabling the exploitation of spectral samples usually not used for limb sounding due to their opacity. A second problem for tomographic retrievals is that advection, which can be neglected for conventional retrievals, plays an important role for the time-scales involved in a tomographic measurement flight. This paper presents a method to diagnose the effect of a time-varying atmosphere on a 3-D retrieval and demonstrates an effective way to compensate for effects of advection by incorporating wind-fields from meteorological datasets as a priori information.

  15. Operational Retrieval of aerosol optical depth over Indian subcontinent and Indian Ocean using INSAT-3D/Imager product validation

    NASA Astrophysics Data System (ADS)

    Mishra, M. K.; Rastogi, G.; Chauhan, P.

    2014-11-01

    Aerosol optical depth (AOD) over Indian subcontinent and Indian Ocean region is derived operationally for the first time from the geostationary earth orbit (GEO) satellite INSAT-3D Imager data at 0.65 μm wavelength. Single visible channel algorithm based on clear sky composites gives larger retrieval error in AOD than other multiple channel algorithms due to errors in estimating surface reflectance and atmospheric property. However, since MIR channel signal is insensitive to the presence of most aerosols, therefore in present study, AOD retrieval algorithm employs both visible (centred at 0.65 μm) and mid-infrared (MIR) band (centred at 3.9 μm) measurements, and allows us to monitor transport of aerosols at higher temporal resolution. Comparisons made between INSAT-3D derived AOD (τI) and MODIS derived AOD (τM) co-located in space (at 1° resolution) and time during January, February and March (JFM) 2014 encompasses 1165, 1052 and 900 pixels, respectively. Good agreement found between τI and τM during JFM 2014 with linear correlation coefficients (R) of 0.87, 0.81 and 0.76, respectively. The extensive validation made during JFM 2014 encompasses 215 co-located AOD in space and time derived by INSAT 3D (τI) and 10 sun-photometers (τA) that includes 9 AERONET (Aerosol Robotic Network) and 1 handheld sun-photometer site. INSAT-3D derived AOD i.e. τI, is found within the retrieval errors of τI = ±0.07 ±0.15τA with linear correlation coefficient (R) of 0.90 and root mean square error equal (RMSE) to 0.06. Present work shows that INSAT-3D aerosol products can be used quantitatively in many applications with caution for possible residual clouds, snow/ice, and water contamination.

  16. Learning the 3-D structure of objects from 2-D views depends on shape, not format

    PubMed Central

    Tian, Moqian; Yamins, Daniel; Grill-Spector, Kalanit

    2016-01-01

    Humans can learn to recognize new objects just from observing example views. However, it is unknown what structural information enables this learning. To address this question, we manipulated the amount of structural information given to subjects during unsupervised learning by varying the format of the trained views. We then tested how format affected participants' ability to discriminate similar objects across views that were rotated 90° apart. We found that, after training, participants' performance increased and generalized to new views in the same format. Surprisingly, the improvement was similar across line drawings, shape from shading, and shape from shading + stereo even though the latter two formats provide richer depth information compared to line drawings. In contrast, participants' improvement was significantly lower when training used silhouettes, suggesting that silhouettes do not have enough information to generate a robust 3-D structure. To test whether the learned object representations were format-specific or format-invariant, we examined if learning novel objects from example views transfers across formats. We found that learning objects from example line drawings transferred to shape from shading and vice versa. These results have important implications for theories of object recognition because they suggest that (a) learning the 3-D structure of objects does not require rich structural cues during training as long as shape information of internal and external features is provided and (b) learning generates shape-based object representations independent of the training format. PMID:27153196

  17. Learning the 3-D structure of objects from 2-D views depends on shape, not format.

    PubMed

    Tian, Moqian; Yamins, Daniel; Grill-Spector, Kalanit

    2016-05-01

    Humans can learn to recognize new objects just from observing example views. However, it is unknown what structural information enables this learning. To address this question, we manipulated the amount of structural information given to subjects during unsupervised learning by varying the format of the trained views. We then tested how format affected participants' ability to discriminate similar objects across views that were rotated 90° apart. We found that, after training, participants' performance increased and generalized to new views in the same format. Surprisingly, the improvement was similar across line drawings, shape from shading, and shape from shading + stereo even though the latter two formats provide richer depth information compared to line drawings. In contrast, participants' improvement was significantly lower when training used silhouettes, suggesting that silhouettes do not have enough information to generate a robust 3-D structure. To test whether the learned object representations were format-specific or format-invariant, we examined if learning novel objects from example views transfers across formats. We found that learning objects from example line drawings transferred to shape from shading and vice versa. These results have important implications for theories of object recognition because they suggest that (a) learning the 3-D structure of objects does not require rich structural cues during training as long as shape information of internal and external features is provided and (b) learning generates shape-based object representations independent of the training format. PMID:27153196

  18. Registration of untypical 3D objects in Polish cadastre - do we need 3D cadastre? / Rejestracja nietypowych obiektów 3D w polskim katastrze - czy istnieje potrzeba wdrożenia katastru 3D?

    NASA Astrophysics Data System (ADS)

    Marcin, Karabin

    2012-11-01

    Polish cadastral system consists of two registers: cadastre and land register. The cadastre register data on cadastral objects (land, buildings and premises) in particular location (in a two-dimensional coordinate system) and their attributes as well as data about the owners. The land register contains data concerned ownerships and other rights to the property. Registration of a land parcel without spatial objects located on the surface is not problematic. Registration of buildings and premises in typical cases is not a problem either. The situation becomes more complicated in cases of multiple use of space above the parcel and with more complex construction of the buildings. The paper presents rules concerning the registration of various untypical 3D objects located within the city of Warsaw. The analysis of the data concerning those objects registered in the cadastre and land register is presented in the paper. And this is the next part of the author's detailed research. The aim of this paper is to answer the question if we really need 3D cadastre in Poland. Polski system katastralny składa się z dwóch rejestrów: ewidencji gruntów i budynków (katastru nieruchomosci) oraz ksiąg wieczystych. W ewidencji gruntów i budynków (katastrze nieruchomości) rejestrowane są dane o położeniu (w dwuwymiarowym układzie współrzędnych), atrybuty oraz dane o właścicielach obiektów katastralnych (działek, budynków i lokali), w księgach wieczystych oprócz danych właścicielskich, inne prawa do nieruchomości. Rejestracja działki bez obiektów przestrzennych położonych na jej powierzchni nie stanowi problemu. Także rejestracja budynków i lokali w typowych przypadkach nie stanowi trudności. Sytuacja staje się bardziej skomplikowana w przypadku wielokrotnego użytkowania przestrzeni powyzej lub poniżej powierzchni działki oraz w przypadku budynków o złożonej konstrukcji. W artykule przedstawiono zasady związane z rejestracją nietypowych obiektów 3

  19. 220GHz wideband 3D imaging radar for concealed object detection technology development and phenomenology studies

    NASA Astrophysics Data System (ADS)

    Robertson, Duncan A.; Macfarlane, David G.; Bryllert, Tomas

    2016-05-01

    We present a 220 GHz 3D imaging `Pathfinder' radar developed within the EU FP7 project CONSORTIS (Concealed Object Stand-Off Real-Time Imaging for Security) which has been built to address two objectives: (i) to de-risk the radar hardware development and (ii) to enable the collection of phenomenology data with ~1 cm3 volumetric resolution. The radar combines a DDS-based chirp generator and self-mixing multiplier technology to achieve a 30 GHz bandwidth chirp with such high linearity that the raw point response is close to ideal and only requires minor nonlinearity compensation. The single transceiver is focused with a 30 cm lens mounted on a gimbal to acquire 3D volumetric images of static test targets and materials.

  20. Minimal camera networks for 3D image based modeling of cultural heritage objects.

    PubMed

    Alsadik, Bashar; Gerke, Markus; Vosselman, George; Daham, Afrah; Jasim, Luma

    2014-01-01

    3D modeling of cultural heritage objects like artifacts, statues and buildings is nowadays an important tool for virtual museums, preservation and restoration. In this paper, we introduce a method to automatically design a minimal imaging network for the 3D modeling of cultural heritage objects. This becomes important for reducing the image capture time and processing when documenting large and complex sites. Moreover, such a minimal camera network design is desirable for imaging non-digitally documented artifacts in museums and other archeological sites to avoid disturbing the visitors for a long time and/or moving delicate precious objects to complete the documentation task. The developed method is tested on the Iraqi famous statue "Lamassu". Lamassu is a human-headed winged bull of over 4.25 m in height from the era of Ashurnasirpal II (883-859 BC). Close-range photogrammetry is used for the 3D modeling task where a dense ordered imaging network of 45 high resolution images were captured around Lamassu with an object sample distance of 1 mm. These images constitute a dense network and the aim of our study was to apply our method to reduce the number of images for the 3D modeling and at the same time preserve pre-defined point accuracy. Temporary control points were fixed evenly on the body of Lamassu and measured by using a total station for the external validation and scaling purpose. Two network filtering methods are implemented and three different software packages are used to investigate the efficiency of the image orientation and modeling of the statue in the filtered (reduced) image networks. Internal and external validation results prove that minimal image networks can provide highly accurate records and efficiency in terms of visualization, completeness, processing time (>60% reduction) and the final accuracy of 1 mm. PMID:24670718

  1. Minimal Camera Networks for 3D Image Based Modeling of Cultural Heritage Objects

    PubMed Central

    Alsadik, Bashar; Gerke, Markus; Vosselman, George; Daham, Afrah; Jasim, Luma

    2014-01-01

    3D modeling of cultural heritage objects like artifacts, statues and buildings is nowadays an important tool for virtual museums, preservation and restoration. In this paper, we introduce a method to automatically design a minimal imaging network for the 3D modeling of cultural heritage objects. This becomes important for reducing the image capture time and processing when documenting large and complex sites. Moreover, such a minimal camera network design is desirable for imaging non-digitally documented artifacts in museums and other archeological sites to avoid disturbing the visitors for a long time and/or moving delicate precious objects to complete the documentation task. The developed method is tested on the Iraqi famous statue “Lamassu”. Lamassu is a human-headed winged bull of over 4.25 m in height from the era of Ashurnasirpal II (883–859 BC). Close-range photogrammetry is used for the 3D modeling task where a dense ordered imaging network of 45 high resolution images were captured around Lamassu with an object sample distance of 1 mm. These images constitute a dense network and the aim of our study was to apply our method to reduce the number of images for the 3D modeling and at the same time preserve pre-defined point accuracy. Temporary control points were fixed evenly on the body of Lamassu and measured by using a total station for the external validation and scaling purpose. Two network filtering methods are implemented and three different software packages are used to investigate the efficiency of the image orientation and modeling of the statue in the filtered (reduced) image networks. Internal and external validation results prove that minimal image networks can provide highly accurate records and efficiency in terms of visualization, completeness, processing time (>60% reduction) and the final accuracy of 1 mm. PMID:24670718

  2. The representation of moving 3-D objects in apparent motion perception.

    PubMed

    Hidaka, Souta; Kawachi, Yousuke; Gyoba, Jiro

    2009-08-01

    In the present research, we investigated the depth information contained in the representations of apparently moving 3-D objects. By conducting three experiments, we measured the magnitude of representational momentum (RM) as an index of the consistency of an object's representation. Experiment 1A revealed that RM magnitude was greater when shaded, convex, apparently moving objects shifted to a flat circle than when they shifted to a shaded, concave, hemisphere. The difference diminished when the apparently moving objects were concave hemispheres (Experiment 1B). Using luminance-polarized circles, Experiment 2 confirmed that these results were not due to the luminance information of shading. Experiment 3 demonstrated that RM magnitude was greater when convex apparently moving objects shifted to particular blurred convex hemispheres with low-pass filtering than when they shifted to concave hemispheres. These results suggest that the internal object's representation in apparent motion contains incomplete depth information intermediate between that of 2-D and 3-D objects, particularly with regard to convexity information with low-spatial-frequency components. PMID:19633345

  3. An object-oriented simulator for 3D digital breast tomosynthesis imaging system.

    PubMed

    Seyyedi, Saeed; Cengiz, Kubra; Kamasak, Mustafa; Yildirim, Isa

    2013-01-01

    Digital breast tomosynthesis (DBT) is an innovative imaging modality that provides 3D reconstructed images of breast to detect the breast cancer. Projections obtained with an X-ray source moving in a limited angle interval are used to reconstruct 3D image of breast. Several reconstruction algorithms are available for DBT imaging. Filtered back projection algorithm has traditionally been used to reconstruct images from projections. Iterative reconstruction algorithms such as algebraic reconstruction technique (ART) were later developed. Recently, compressed sensing based methods have been proposed in tomosynthesis imaging problem. We have developed an object-oriented simulator for 3D digital breast tomosynthesis (DBT) imaging system using C++ programming language. The simulator is capable of implementing different iterative and compressed sensing based reconstruction methods on 3D digital tomosynthesis data sets and phantom models. A user friendly graphical user interface (GUI) helps users to select and run the desired methods on the designed phantom models or real data sets. The simulator has been tested on a phantom study that simulates breast tomosynthesis imaging problem. Results obtained with various methods including algebraic reconstruction technique (ART) and total variation regularized reconstruction techniques (ART+TV) are presented. Reconstruction results of the methods are compared both visually and quantitatively by evaluating performances of the methods using mean structural similarity (MSSIM) values. PMID:24371468

  4. Visual Object Recognition with 3D-Aware Features in KITTI Urban Scenes

    PubMed Central

    Yebes, J. Javier; Bergasa, Luis M.; García-Garrido, Miguel Ángel

    2015-01-01

    Driver assistance systems and autonomous robotics rely on the deployment of several sensors for environment perception. Compared to LiDAR systems, the inexpensive vision sensors can capture the 3D scene as perceived by a driver in terms of appearance and depth cues. Indeed, providing 3D image understanding capabilities to vehicles is an essential target in order to infer scene semantics in urban environments. One of the challenges that arises from the navigation task in naturalistic urban scenarios is the detection of road participants (e.g., cyclists, pedestrians and vehicles). In this regard, this paper tackles the detection and orientation estimation of cars, pedestrians and cyclists, employing the challenging and naturalistic KITTI images. This work proposes 3D-aware features computed from stereo color images in order to capture the appearance and depth peculiarities of the objects in road scenes. The successful part-based object detector, known as DPM, is extended to learn richer models from the 2.5D data (color and disparity), while also carrying out a detailed analysis of the training pipeline. A large set of experiments evaluate the proposals, and the best performing approach is ranked on the KITTI website. Indeed, this is the first work that reports results with stereo data for the KITTI object challenge, achieving increased detection ratios for the classes car and cyclist compared to a baseline DPM. PMID:25903553

  5. A Global Hypothesis Verification Framework for 3D Object Recognition in Clutter.

    PubMed

    Aldoma, Aitor; Tombari, Federico; Stefano, Luigi Di; Vincze, Markus

    2016-07-01

    Pipelines to recognize 3D objects despite clutter and occlusions usually end up with a final verification stage whereby recognition hypotheses are validated or dismissed based on how well they explain sensor measurements. Unlike previous work, we propose a Global Hypothesis Verification (GHV) approach which regards all hypotheses jointly so as to account for mutual interactions. GHV provides a principled framework to tackle the complexity of our visual world by leveraging on a plurality of recognition paradigms and cues. Accordingly, we present a 3D object recognition pipeline deploying both global and local 3D features as well as shape and color. Thereby, and facilitated by the robustness of the verification process, diverse object hypotheses can be gathered and weak hypotheses need not be suppressed too early to trade sensitivity for specificity. Experiments demonstrate the effectiveness of our proposal, which significantly improves over the state-of-art and attains ideal performance (no false negatives, no false positives) on three out of the six most relevant and challenging benchmark datasets. PMID:26485476

  6. Visual Object Recognition with 3D-Aware Features in KITTI Urban Scenes.

    PubMed

    Yebes, J Javier; Bergasa, Luis M; García-Garrido, Miguel Ángel

    2015-01-01

    Driver assistance systems and autonomous robotics rely on the deployment of several sensors for environment perception. Compared to LiDAR systems, the inexpensive vision sensors can capture the 3D scene as perceived by a driver in terms of appearance and depth cues. Indeed, providing 3D image understanding capabilities to vehicles is an essential target in order to infer scene semantics in urban environments. One of the challenges that arises from the navigation task in naturalistic urban scenarios is the detection of road participants (e.g., cyclists, pedestrians and vehicles). In this regard, this paper tackles the detection and orientation estimation of cars, pedestrians and cyclists, employing the challenging and naturalistic KITTI images. This work proposes 3D-aware features computed from stereo color images in order to capture the appearance and depth peculiarities of the objects in road scenes. The successful part-based object detector, known as DPM, is extended to learn richer models from the 2.5D data (color and disparity), while also carrying out a detailed analysis of the training pipeline. A large set of experiments evaluate the proposals, and the best performing approach is ranked on the KITTI website. Indeed, this is the first work that reports results with stereo data for the KITTI object challenge, achieving increased detection ratios for the classes car and cyclist compared to a baseline DPM. PMID:25903553

  7. Determining the 3-D structure and motion of objects using a scanning laser range sensor

    NASA Technical Reports Server (NTRS)

    Nandhakumar, N.; Smith, Philip W.

    1993-01-01

    In order for the EVAHR robot to autonomously track and grasp objects, its vision system must be able to determine the 3-D structure and motion of an object from a sequence of sensory images. This task is accomplished by the use of a laser radar range sensor which provides dense range maps of the scene. Unfortunately, the currently available laser radar range cameras use a sequential scanning approach which complicates image analysis. Although many algorithms have been developed for recognizing objects from range images, none are suited for use with single beam, scanning, time-of-flight sensors because all previous algorithms assume instantaneous acquisition of the entire image. This assumption is invalid since the EVAHR robot is equipped with a sequential scanning laser range sensor. If an object is moving while being imaged by the device, the apparent structure of the object can be significantly distorted due to the significant non-zero delay time between sampling each image pixel. If an estimate of the motion of the object can be determined, this distortion can be eliminated; but, this leads to the motion-structure paradox - most existing algorithms for 3-D motion estimation use the structure of objects to parameterize their motions. The goal of this research is to design a rigid-body motion recovery technique which overcomes this limitation. The method being developed is an iterative, linear, feature-based approach which uses the non-zero image acquisition time constraint to accurately recover the motion parameters from the distorted structure of the 3-D range maps. Once the motion parameters are determined, the structural distortion in the range images is corrected.

  8. Applying Mean-Shift - Clustering for 3D object detection in remote sensing data

    NASA Astrophysics Data System (ADS)

    Simon, Jürgen-Lorenz; Diederich, Malte; Troemel, Silke

    2013-04-01

    The timely warning and forecasting of high-impact weather events is crucial for life, safety and economy. Therefore, the development and improvement of methods for detection and nowcasting / short-term forecasting of these events is an ongoing research question. A new 3D object detection and tracking algorithm is presented. Within the project "object-based analysis and seamless predictin (OASE)" we address a better understanding and forecasting of convective events based on the synergetic use of remotely sensed data and new methods for detection, nowcasting, validation and assimilation. In order to gain advanced insight into the lifecycle of convective cells, we perform an object-detection on a new high-resolution 3D radar- and satellite based composite and plan to track the detected objects over time, providing us with a model of the lifecycle. The insights in the lifecycle will be used in order to improve prediction of convective events in the nowcasting time scale, as well as a new type of data to be assimilated into numerical weather models, thus seamlessly bridging the gap between nowcasting and NWP.. The object identification (or clustering) is performed using a technique borrowed from computer vision, called mean-shift clustering. Mean-Shift clustering works without many of the parameterizations or rigid threshold schemes employed by many existing schemes (e. g. KONRAD, TITAN, Trace-3D), which limit the tracking to fully matured, convective cells of significant size and/or strength. Mean-Shift performs without such limiting definitions, providing a wider scope for studying larger classes of phenomena and providing a vehicle for research into the object definition itself. Since the mean-shift clustering technique could be applied on many types of remote-sensing and model data for object detection, it is of general interest to the remote sensing and modeling community. The focus of the presentation is the introduction of this technique and the results of its

  9. Color and size interactions in a real 3D object similarity task.

    PubMed

    Ling, Yazhu; Hurlbert, Anya

    2004-08-31

    In the natural world, objects are characterized by a variety of attributes, including color and shape. The contributions of these two attributes to object recognition are typically studied independently of each other, yet they are likely to interact in natural tasks. Here we examine whether color and size (a component of shape) interact in a real three-dimensional (3D) object similarity task, using solid domelike objects whose distinct apparent surface colors are independently controlled via spatially restricted illumination from a data projector hidden to the observer. The novel experimental setup preserves natural cues to 3D shape from shading, binocular disparity, motion parallax, and surface texture cues, while also providing the flexibility and ease of computer control. Observers performed three distinct tasks: two unimodal discrimination tasks, and an object similarity task. Depending on the task, the observer was instructed to select the indicated alternative object which was "bigger than," "the same color as," or "most similar to" the designated reference object, all of which varied in both size and color between trials. For both unimodal discrimination tasks, discrimination thresholds for the tested attribute (e.g., color) were increased by differences in the secondary attribute (e.g., size), although this effect was more robust in the color task. For the unimodal size-discrimination task, the strongest effects of the secondary attribute (color) occurred as a perceptual bias, which we call the "saturation-size effect": Objects with more saturated colors appear larger than objects with less saturated colors. In the object similarity task, discrimination thresholds for color or size differences were significantly larger than in the unimodal discrimination tasks. We conclude that color and size interact in determining object similarity, and are effectively analyzed on a coarser scale, due to noise in the similarity estimates of the individual attributes

  10. Determining canonical views of 3D object using minimum description length criterion and compressive sensing method

    NASA Astrophysics Data System (ADS)

    Chen, Ping-Feng; Krim, Hamid

    2008-02-01

    In this paper, we propose using two methods to determine the canonical views of 3D objects: minimum description length (MDL) criterion and compressive sensing method. MDL criterion searches for the description length that achieves the balance between model accuracy and parsimony. It takes the form of the sum of a likelihood and a penalizing term, where the likelihood is in favor of model accuracy such that more views assists the description of an object, while the second term penalizes lengthy description to prevent overfitting of the model. In order to devise the likelihood term, we propose a model to represent a 3D object as the weighted sum of multiple range images, which is used in the second method to determine the canonical views as well. In compressive sensing method, an intelligent way of parsimoniously sampling an object is presented. We make direct inference from Donoho1 and Candes'2 work, and adapt it to our model. Each range image is viewed as a projection, or a sample, of a 3D model, and by using compressive sensing theory, we are able to reconstruct the object with an overwhelming probability by scarcely sensing the object in a random manner. Compressive sensing is different from traditional compressing method in the sense that the former compress things in the sampling stage while the later collects a large number of samples and then compressing mechanism is carried out thereafter. Compressive sensing scheme is particularly useful when the number of sensors are limited or the sampling machinery cost much resource or time.

  11. 3D object optonumerical acquisition methods for CAD/CAM and computer graphics systems

    NASA Astrophysics Data System (ADS)

    Sitnik, Robert; Kujawinska, Malgorzata; Pawlowski, Michal E.; Woznicki, Jerzy M.

    1999-08-01

    The creation of a virtual object for CAD/CAM and computer graphics on the base of data gathered by full-field optical measurement of 3D object is presented. The experimental co- ordinates are alternatively obtained by combined fringe projection/photogrammetry based system or fringe projection/virtual markers setup. The new and fully automatic procedure which process the cloud of measured points into triangular mesh accepted by CAD/CAM and computer graphics systems is presented. Its applicability for various classes of objects is tested including the error analysis of virtual objects generated. The usefulness of the method is proved by applying the virtual object in rapid prototyping system and in computer graphics environment.

  12. Flexible simulation strategy for modeling 3D cultural objects based on multisource remotely sensed imagery

    NASA Astrophysics Data System (ADS)

    Guienko, Guennadi; Levin, Eugene

    2003-01-01

    New ideas and solutions never come alone. Although automated feature extraction is not sufficiently mature to move from the realm of scientific investigation into the category of production technology, a new goal has arisen: 3D simulation of real-world objects, extracted from images. This task, which evolved from feature extraction and is not an easy task itself, becomes even more complex, multi-leveled, and often uncertain and fuzzy when one exploits time-sequenced multi-source remotely sensed visual data. The basic components of the process are familiar image processing tasks: fusion of various types of imagery, automatic recognition of objects, removng those objects from the source images, and replacing them in the images with their realistic simulated "twin" object rendering. This paper discusses how to aggregate the most appropriate approach to each task into one technological process in order to develop a Manipulator for Visual Simulation of 3D objects (ManVIS) that is independent or imagery/format/media. The technology could be made general by combining a number of competent special purpose algorithms under appropriate contextual, geometric, spatial, and temporal constraints derived from a-priori knowledge. This could be achieved by planning the simulation in an Open Structure Simulation Strategy Manager (O3SM) a distinct component of ManVIS building the simulation strategy before beginning actual image manipulation.

  13. Differential and relaxed image foresting transform for graph-cut segmentation of multiple 3D objects.

    PubMed

    Moya, Nikolas; Falcão, Alexandre X; Ciesielski, Krzysztof C; Udupa, Jayaram K

    2014-01-01

    Graph-cut algorithms have been extensively investigated for interactive binary segmentation, when the simultaneous delineation of multiple objects can save considerable user's time. We present an algorithm (named DRIFT) for 3D multiple object segmentation based on seed voxels and Differential Image Foresting Transforms (DIFTs) with relaxation. DRIFT stands behind efficient implementations of some state-of-the-art methods. The user can add/remove markers (seed voxels) along a sequence of executions of the DRIFT algorithm to improve segmentation. Its first execution takes linear time with the image's size, while the subsequent executions for corrections take sublinear time in practice. At each execution, DRIFT first runs the DIFT algorithm, then it applies diffusion filtering to smooth boundaries between objects (and background) and, finally, it corrects possible objects' disconnection occurrences with respect to their seeds. We evaluate DRIFT in 3D CT-images of the thorax for segmenting the arterial system, esophagus, left pleural cavity, right pleural cavity, trachea and bronchi, and the venous system. PMID:25333179

  14. X-ray stereo imaging for micro 3D motions within non-transparent objects

    NASA Astrophysics Data System (ADS)

    Salih, Wasil H. M.; Buytaert, Jan A. N.; Dirckx, Joris J. J.

    2012-03-01

    We propose a new technique to measure the 3D motion of marker points along a straight path within an object using x-ray stereo projections. From recordings of two x-ray projections with 90° separation angle, the 3D coordinates of marker points can be determined. By synchronizing the x-ray exposure time to the motion event, a moving marker leaves a trace in the image of which the gray scale is linearly proportional to the marker velocity. From the gray scale along the motion path, the 3D motion (velocity) is obtained. The path of motion was reconstructed and compared with the applied waveform. The results showed that the accuracy is in order of 5%. The difference of displacement amplitude between the new method and laser vibrometry was less than 5μm. We demonstrated the method on the malleus ossicle motion in the gerbil middle ear as a function of pressure applied on the eardrum. The new method has the advantage over existing methods such as laser vibrometry that the structures under study do not need to be visually exposed. Due to the short measurement time and the high resolution, the method can be useful in the field of biomechanics for a variety of applications.

  15. Efficient Use of Video for 3d Modelling of Cultural Heritage Objects

    NASA Astrophysics Data System (ADS)

    Alsadik, B.; Gerke, M.; Vosselman, G.

    2015-03-01

    Currently, there is a rapid development in the techniques of the automated image based modelling (IBM), especially in advanced structure-from-motion (SFM) and dense image matching methods, and camera technology. One possibility is to use video imaging to create 3D reality based models of cultural heritage architectures and monuments. Practically, video imaging is much easier to apply when compared to still image shooting in IBM techniques because the latter needs a thorough planning and proficiency. However, one is faced with mainly three problems when video image sequences are used for highly detailed modelling and dimensional survey of cultural heritage objects. These problems are: the low resolution of video images, the need to process a large number of short baseline video images and blur effects due to camera shake on a significant number of images. In this research, the feasibility of using video images for efficient 3D modelling is investigated. A method is developed to find the minimal significant number of video images in terms of object coverage and blur effect. This reduction in video images is convenient to decrease the processing time and to create a reliable textured 3D model compared with models produced by still imaging. Two experiments for modelling a building and a monument are tested using a video image resolution of 1920×1080 pixels. Internal and external validations of the produced models are applied to find out the final predicted accuracy and the model level of details. Related to the object complexity and video imaging resolution, the tests show an achievable average accuracy between 1 - 5 cm when using video imaging, which is suitable for visualization, virtual museums and low detailed documentation.

  16. Prototyping a Sensor Enabled 3d Citymodel on Geospatial Managed Objects

    NASA Astrophysics Data System (ADS)

    Kjems, E.; Kolář, J.

    2013-09-01

    One of the major development efforts within the GI Science domain are pointing at sensor based information and the usage of real time information coming from geographic referenced features in general. At the same time 3D City models are mostly justified as being objects for visualization purposes rather than constituting the foundation of a geographic data representation of the world. The combination of 3D city models and real time information based systems though can provide a whole new setup for data fusion within an urban environment and provide time critical information preserving our limited resources in the most sustainable way. Using 3D models with consistent object definitions give us the possibility to avoid troublesome abstractions of reality, and design even complex urban systems fusing information from various sources of data. These systems are difficult to design with the traditional software development approach based on major software packages and traditional data exchange. The data stream is varying from urban domain to urban domain and from system to system why it is almost impossible to design a complete system taking care of all thinkable instances now and in the future within one constraint software design complex. On several occasions we have been advocating for a new end advanced formulation of real world features using the concept of Geospatial Managed Objects (GMO). This paper presents the outcome of the InfraWorld project, a 4 million Euro project financed primarily by the Norwegian Research Council where the concept of GMO's have been applied in various situations on various running platforms of an urban system. The paper will be focusing on user experiences and interfaces rather then core technical and developmental issues. The project was primarily focusing on prototyping rather than realistic implementations although the results concerning applicability are quite clear.

  17. 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

  18. Measuring the 3D shape of high temperature objects using blue sinusoidal structured light

    NASA Astrophysics Data System (ADS)

    Zhao, Xianling; Liu, Jiansheng; Zhang, Huayu; Wu, Yingchun

    2015-12-01

    The visible light radiated by some high temperature objects (less than 1200 °C) almost lies in the red and infrared waves. It will interfere with structured light projected on a forging surface if phase measurement profilometry (PMP) is used to measure the shapes of objects. In order to obtain a clear deformed pattern image, a 3D measurement method based on blue sinusoidal structured light is proposed in this present work. Moreover, a method for filtering deformed pattern images is presented for correction of the unwrapping phase. Blue sinusoidal phase-shifting fringe pattern images are projected on the surface by a digital light processing (DLP) projector, and then the deformed patterns are captured by a 3-CCD camera. The deformed pattern images are separated into R, G and B color components by the software. The B color images filtered by a low-pass filter are used to calculate the fringe order. Consequently, the 3D shape of a high temperature object is obtained by the unwrapping phase and the calibration parameter matrixes of the DLP projector and 3-CCD camera. The experimental results show that the unwrapping phase is completely corrected with the filtering method by removing the high frequency noise from the first harmonic of the B color images. The measurement system can complete the measurement in a few seconds with a relative error of less than 1 : 1000.

  19. Calibration target reconstruction for 3-D vision inspection system of large-scale engineering objects

    NASA Astrophysics Data System (ADS)

    Yin, Yongkai; Peng, Xiang; Guan, Yingjian; Liu, Xiaoli; Li, Ameng

    2010-11-01

    It is usually difficult to calibrate the 3-D vision inspection system that may be employed to measure the large-scale engineering objects. One of the challenges is how to in-situ build-up a large and precise calibration target. In this paper, we present a calibration target reconstruction strategy to solve such a problem. First, we choose one of the engineering objects to be inspected as a calibration target, on which we paste coded marks on the object surface. Next, we locate and decode marks to get homologous points. From multiple camera images, the fundamental matrix between adjacent images can be estimated, and then the essential matrix can be derived with priori known camera intrinsic parameters and decomposed to obtain camera extrinsic parameters. Finally, we are able to obtain the initial 3D coordinates with binocular stereo vision reconstruction, and then optimize them with the bundle adjustment by considering the lens distortions, leading to a high-precision calibration target. This reconstruction strategy has been applied to the inspection of an industrial project, from which the proposed method is successfully validated.

  20. 3D Object Recognition using Gabor Feature Extraction and PCA-FLD Projections of Holographically Sensed Data

    NASA Astrophysics Data System (ADS)

    Yeom, Seokwon; Javidi, Bahram

    In this research, a 3D object classification technique using a single hologram has been presented. The PCA-FLD classifier with feature vectors based on Gabor wavelets has been utilized for this purpose. Training and test data of the 3D objects were obtained by computational holographic imaging. We were able to classify 3D objects used in the experiments with a few reconstructed planes of the hologram. The Gabor approach appears to be a good feature extractor for hologram-based 3D classification. The FLD combined with the PCA proved to be a very efficient classifier even with a few training data. Substantial dimensionality reduction was achieved by using the proposed technique for 3D classification problem using holographic imaging. As a consequence, we were able to classify different classes of 3D objects using computer-reconstructed holographic images.

  1. Segmentation of 3D tubular objects with adaptive front propagation and minimal tree extraction for 3D medical imaging.

    PubMed

    Cohen, Laurent D; Deschamps, Thomas

    2007-08-01

    We present a new fast approach for segmentation of thin branching structures, like vascular trees, based on Fast-Marching (FM) and Level Set (LS) methods. FM allows segmentation of tubular structures by inflating a "long balloon" from a user given single point. However, when the tubular shape is rather long, the front propagation may blow up through the boundary of the desired shape close to the starting point. Our contribution is focused on a method to propagate only the useful part of the front while freezing the rest of it. We demonstrate its ability to segment quickly and accurately tubular and tree-like structures. We also develop a useful stopping criterion for the causal front propagation. We finally derive an efficient algorithm for extracting an underlying 1D skeleton of the branching objects, with minimal path techniques. Each branch being represented by its centerline, we automatically detect the bifurcations, leading to the "Minimal Tree" representation. This so-called "Minimal Tree" is very useful for visualization and quantification of the pathologies in our anatomical data sets. We illustrate our algorithms by applying it to several arteries datasets. PMID:17671862

  2. Test Objectives for the Saltcake Dissolution Retrieval Demonstration

    SciTech Connect

    DEFIGH PRICE, C.

    2000-09-22

    This document describes the objectives the Saltcake Dissolution Retrieval Demonstration. The near term strategy for single-shell tank waste retrieval activities has shifted from focusing on maximizing the number of tanks entered for retrieval (regardless of waste volume or content) to a focus on scheduling the retrieval of wastes from those single-shell tanks with a high volume of contaminants of concern. These contaminants are defined as mobile, long-lived radionuclides that have a potential of reaching the groundwater and the Columbia River. This strategy also focuses on the performance of key retrieval technology demonstrations, including the Saltcake Dissolution Retrieval Demonstration, in a variety of waste forms and tank farm locations to establish a technical basis for future work. The work scope will also focus on the performance of risk assessment, retrieval performance evaluations (RPE) and incorporating vadose zone characterization data on a tank-by-tank basis, and on updating tank farm closure/post closure work plans. The deployment of a retrieval technology other than Past-Practice Sluicing (PPS) allows determination of limits of technical capabilities, as well as, providing a solid planning basis for future SST retrievals. This saltcake dissolution technology deployment test will determine if saltcake dissolution is a viable retrieval option for SST retrieval. CH2M Hill Hanford Group (CHG) recognizes the SST retrieval mission is key to the success of the River Protection Project (RPP) and the overall completion of the Hanford Site cleanup. The objectives outlined in this document will be incorporated into and used to develop the test and evaluation plan for saltcake dissolution retrievals. The test and evaluation plan will be developed in fiscal year 2001.

  3. PAPERS: A Simple Object-Oriented Text Retrieval System.

    ERIC Educational Resources Information Center

    Wade, Stephen

    1993-01-01

    Describes how an interactive text retrieval system with natural language queries is used in information studies education. The benefits of programing methods involving encapsulation and inheritance are explained in terms of reusability and extendibility, and future plans to produce a library of reusable objects for information retrieval are…

  4. Recognizing Objects in 3D Point Clouds with Multi-Scale Local Features

    PubMed Central

    Lu, Min; Guo, Yulan; Zhang, Jun; Ma, Yanxin; Lei, Yinjie

    2014-01-01

    Recognizing 3D objects from point clouds in the presence of significant clutter and occlusion is a highly challenging task. In this paper, we present a coarse-to-fine 3D object recognition algorithm. During the phase of offline training, each model is represented with a set of multi-scale local surface features. During the phase of online recognition, a set of keypoints are first detected from each scene. The local surfaces around these keypoints are further encoded with multi-scale feature descriptors. These scene features are then matched against all model features to generate recognition hypotheses, which include model hypotheses and pose hypotheses. Finally, these hypotheses are verified to produce recognition results. The proposed algorithm was tested on two standard datasets, with rigorous comparisons to the state-of-the-art algorithms. Experimental results show that our algorithm was fully automatic and highly effective. It was also very robust to occlusion and clutter. It achieved the best recognition performance on all of these datasets, showing its superiority compared to existing algorithms. PMID:25517694

  5. A method of 3D object recognition and localization in a cloud of points

    NASA Astrophysics Data System (ADS)

    Bielicki, Jerzy; Sitnik, Robert

    2013-12-01

    The proposed method given in this article is prepared for analysis of data in the form of cloud of points directly from 3D measurements. It is designed for use in the end-user applications that can directly be integrated with 3D scanning software. The method utilizes locally calculated feature vectors (FVs) in point cloud data. Recognition is based on comparison of the analyzed scene with reference object library. A global descriptor in the form of a set of spatially distributed FVs is created for each reference model. During the detection process, correlation of subsets of reference FVs with FVs calculated in the scene is computed. Features utilized in the algorithm are based on parameters, which qualitatively estimate mean and Gaussian curvatures. Replacement of differentiation with averaging in the curvatures estimation makes the algorithm more resistant to discontinuities and poor quality of the input data. Utilization of the FV subsets allows to detect partially occluded and cluttered objects in the scene, while additional spatial information maintains false positive rate at a reasonably low level.

  6. Object-adaptive depth compensated inter prediction for depth video coding in 3D video system

    NASA Astrophysics Data System (ADS)

    Kang, Min-Koo; Lee, Jaejoon; Lim, Ilsoon; Ho, Yo-Sung

    2011-01-01

    Nowadays, the 3D video system using the MVD (multi-view video plus depth) data format is being actively studied. The system has many advantages with respect to virtual view synthesis such as an auto-stereoscopic functionality, but compression of huge input data remains a problem. Therefore, efficient 3D data compression is extremely important in the system, and problems of low temporal consistency and viewpoint correlation should be resolved for efficient depth video coding. In this paper, we propose an object-adaptive depth compensated inter prediction method to resolve the problems where object-adaptive mean-depth difference between a current block, to be coded, and a reference block are compensated during inter prediction. In addition, unique properties of depth video are exploited to reduce side information required for signaling decoder to conduct the same process. To evaluate the coding performance, we have implemented the proposed method into MVC (multiview video coding) reference software, JMVC 8.2. Experimental results have demonstrated that our proposed method is especially efficient for depth videos estimated by DERS (depth estimation reference software) discussed in the MPEG 3DV coding group. The coding gain was up to 11.69% bit-saving, and it was even increased when we evaluated it on synthesized views of virtual viewpoints.

  7. Recognizing objects in 3D point clouds with multi-scale local features.

    PubMed

    Lu, Min; Guo, Yulan; Zhang, Jun; Ma, Yanxin; Lei, Yinjie

    2014-01-01

    Recognizing 3D objects from point clouds in the presence of significant clutter and occlusion is a highly challenging task. In this paper, we present a coarse-to-fine 3D object recognition algorithm. During the phase of offline training, each model is represented with a set of multi-scale local surface features. During the phase of online recognition, a set of keypoints are first detected from each scene. The local surfaces around these keypoints are further encoded with multi-scale feature descriptors. These scene features are then matched against all model features to generate recognition hypotheses, which include model hypotheses and pose hypotheses. Finally, these hypotheses are verified to produce recognition results. The proposed algorithm was tested on two standard datasets, with rigorous comparisons to the state-of-the-art algorithms. Experimental results show that our algorithm was fully automatic and highly effective. It was also very robust to occlusion and clutter. It achieved the best recognition performance on all of these datasets, showing its superiority compared to existing algorithms. PMID:25517694

  8. 3D Imaging with a Single-Aperture 3-mm Objective Lens: Concept, Fabrication and Test

    NASA Technical Reports Server (NTRS)

    Korniski, Ron; Bae, Sam Y.; Shearn, Mike; Manohara, Harish; Shahinian, Hrayr

    2011-01-01

    There are many advantages to minimally invasive surgery (MIS). An endoscope is the optical system of choice by the surgeon for MIS. The smaller the incision or opening made to perform the surgery, the smaller the optical system needed. For minimally invasive neurological and skull base surgeries the openings are typically 10-mm in diameter (dime sized) or less. The largest outside diameter (OD) endoscope used is 4mm. A significant drawback to endoscopic MIS is that it only provides a monocular view of the surgical site thereby lacking depth information for the surgeon. A stereo view would provide the surgeon instantaneous depth information of the surroundings within the field of view, a significant advantage especially during brain surgery. Providing 3D imaging in an endoscopic objective lens system presents significant challenges because of the tight packaging constraints. This paper presents a promising new technique for endoscopic 3D imaging that uses a single lens system with complementary multi-bandpass filters (CMBFs), and describes the proof-of-concept demonstrations performed to date validating the technique. These demonstrations of the technique have utilized many commercial off-the-shelf (COTS) components including the ones used in the endoscope objective.

  9. An optimal sensing strategy for recognition and localization of 3-D natural quadric objects

    NASA Technical Reports Server (NTRS)

    Lee, Sukhan; Hahn, Hernsoo

    1991-01-01

    An optimal sensing strategy for an optical proximity sensor system engaged in the recognition and localization of 3-D natural quadric objects is presented. The optimal sensing strategy consists of the selection of an optimal beam orientation and the determination of an optimal probing plane that compose an optimal data collection operation known as an optimal probing. The decision of an optimal probing is based on the measure of discrimination power of a cluster of surfaces on a multiple interpretation image (MII), where the measure of discrimination power is defined in terms of a utility function computing the expected number of interpretations that can be pruned out by a probing. An object representation suitable for active sensing based on a surface description vector (SDV) distribution graph and hierarchical tables is presented. Experimental results are shown.

  10. Knowledge guided object detection and identification in 3D point clouds

    NASA Astrophysics Data System (ADS)

    Karmacharya, A.; Boochs, F.; Tietz, B.

    2015-05-01

    Modern instruments like laser scanner and 3D cameras or image based techniques like structure from motion produce huge point clouds as base for further object analysis. This has considerably changed the way of data compilation away from selective manually guided processes towards automatic and computer supported strategies. However it's still a long way to achieve the quality and robustness of manual processes as data sets are mostly very complex. Looking at existing strategies 3D data processing for object detections and reconstruction rely heavily on either data driven or model driven approaches. These approaches come with their limitation on depending highly on the nature of data and inability to handle any deviation. Furthermore, the lack of capabilities to integrate other data or information in between the processing steps further exposes their limitations. This restricts the approaches to be executed with strict predefined strategy and does not allow deviations when and if new unexpected situations arise. We propose a solution that induces intelligence in the processing activities through the usage of semantics. The solution binds the objects along with other related knowledge domains to the numerical processing to facilitate the detection of geometries and then uses experts' inference rules to annotate them. The solution was tested within the prototypical application of the research project "Wissensbasierte Detektion von Objekten in Punktwolken für Anwendungen im Ingenieurbereich (WiDOP)". The flexibility of the solution is demonstrated through two entirely different USE Case scenarios: Deutsche Bahn (German Railway System) for the outdoor scenarios and Fraport (Frankfort Airport) for the indoor scenarios. Apart from the difference in their environments, they provide different conditions, which the solution needs to consider. While locations of the objects in Fraport were previously known, that of DB were not known at the beginning.

  11. Active learning in the lecture theatre using 3D printed objects.

    PubMed

    Smith, David P

    2016-01-01

    The ability to conceptualize 3D shapes is central to understanding biological processes. The concept that the structure of a biological molecule leads to function is a core principle of the biochemical field. Visualisation of biological molecules often involves vocal explanations or the use of two dimensional slides and video presentations. A deeper understanding of these molecules can however be obtained by the handling of objects. 3D printed biological molecules can be used as active learning tools to stimulate engagement in large group lectures. These models can be used to build upon initial core knowledge which can be delivered in either a flipped form or a more didactic manner. Within the teaching session the students are able to learn by handling, rotating and viewing the objects to gain an appreciation, for example, of an enzyme's active site or the difference between the major and minor groove of DNA. Models and other artefacts can be handled in small groups within a lecture theatre and act as a focal point to generate conversation. Through the approach presented here core knowledge is first established and then supplemented with high level problem solving through a "Think-Pair-Share" cooperative learning strategy. The teaching delivery was adjusted based around experiential learning activities by moving the object from mental cognition and into the physical environment. This approach led to students being able to better visualise biological molecules and a positive engagement in the lecture. The use of objects in teaching allows the lecturer to create interactive sessions that both challenge and enable the student. PMID:27366318

  12. Active learning in the lecture theatre using 3D printed objects

    PubMed Central

    Smith, David P.

    2016-01-01

    The ability to conceptualize 3D shapes is central to understanding biological processes. The concept that the structure of a biological molecule leads to function is a core principle of the biochemical field. Visualisation of biological molecules often involves vocal explanations or the use of two dimensional slides and video presentations. A deeper understanding of these molecules can however be obtained by the handling of objects. 3D printed biological molecules can be used as active learning tools to stimulate engagement in large group lectures. These models can be used to build upon initial core knowledge which can be delivered in either a flipped form or a more didactic manner. Within the teaching session the students are able to learn by handling, rotating and viewing the objects to gain an appreciation, for example, of an enzyme’s active site or the difference between the major and minor groove of DNA. Models and other artefacts can be handled in small groups within a lecture theatre and act as a focal point to generate conversation. Through the approach presented here core knowledge is first established and then supplemented with high level problem solving through a "Think-Pair-Share" cooperative learning strategy. The teaching delivery was adjusted based around experiential learning activities by moving the object from mental cognition and into the physical environment. This approach led to students being able to better visualise biological molecules and a positive engagement in the lecture. The use of objects in teaching allows the lecturer to create interactive sessions that both challenge and enable the student. PMID:27366318

  13. 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

  14. Correlative nanoscale 3D imaging of structure and composition in extended objects.

    PubMed

    Xu, Feng; Helfen, Lukas; Suhonen, Heikki; Elgrabli, Dan; Bayat, Sam; Reischig, Péter; Baumbach, Tilo; Cloetens, Peter

    2012-01-01

    Structure and composition at the nanoscale determine the behavior of biological systems and engineered materials. The drive to understand and control this behavior has placed strong demands on developing methods for high resolution imaging. In general, the improvement of three-dimensional (3D) resolution is accomplished by tightening constraints: reduced manageable specimen sizes, decreasing analyzable volumes, degrading contrasts, and increasing sample preparation efforts. Aiming to overcome these limitations, we present a non-destructive and multiple-contrast imaging technique, using principles of X-ray laminography, thus generalizing tomography towards laterally extended objects. We retain advantages that are usually restricted to 2D microscopic imaging, such as scanning of large areas and subsequent zooming-in towards a region of interest at the highest possible resolution. Our technique permits correlating the 3D structure and the elemental distribution yielding a high sensitivity to variations of the electron density via coherent imaging and to local trace element quantification through X-ray fluorescence. We demonstrate the method by imaging a lithographic nanostructure and an aluminum alloy. Analyzing a biological system, we visualize in lung tissue the subcellular response to toxic stress after exposure to nanotubes. We show that most of the nanotubes are trapped inside alveolar macrophages, while a small portion of the nanotubes has crossed the barrier to the cellular space of the alveolar wall. In general, our method is non-destructive and can be combined with different sample environmental or loading conditions. We therefore anticipate that correlative X-ray nano-laminography will enable a variety of in situ and in operando 3D studies. PMID:23185554

  15. Correlative Nanoscale 3D Imaging of Structure and Composition in Extended Objects

    PubMed Central

    Xu, Feng; Helfen, Lukas; Suhonen, Heikki; Elgrabli, Dan; Bayat, Sam; Reischig, Péter; Baumbach, Tilo; Cloetens, Peter

    2012-01-01

    Structure and composition at the nanoscale determine the behavior of biological systems and engineered materials. The drive to understand and control this behavior has placed strong demands on developing methods for high resolution imaging. In general, the improvement of three-dimensional (3D) resolution is accomplished by tightening constraints: reduced manageable specimen sizes, decreasing analyzable volumes, degrading contrasts, and increasing sample preparation efforts. Aiming to overcome these limitations, we present a non-destructive and multiple-contrast imaging technique, using principles of X-ray laminography, thus generalizing tomography towards laterally extended objects. We retain advantages that are usually restricted to 2D microscopic imaging, such as scanning of large areas and subsequent zooming-in towards a region of interest at the highest possible resolution. Our technique permits correlating the 3D structure and the elemental distribution yielding a high sensitivity to variations of the electron density via coherent imaging and to local trace element quantification through X-ray fluorescence. We demonstrate the method by imaging a lithographic nanostructure and an aluminum alloy. Analyzing a biological system, we visualize in lung tissue the subcellular response to toxic stress after exposure to nanotubes. We show that most of the nanotubes are trapped inside alveolar macrophages, while a small portion of the nanotubes has crossed the barrier to the cellular space of the alveolar wall. In general, our method is non-destructive and can be combined with different sample environmental or loading conditions. We therefore anticipate that correlative X-ray nano-laminography will enable a variety of in situ and in operando 3D studies. PMID:23185554

  16. Object-Centered Knowledge Representation and Information Retrieval.

    ERIC Educational Resources Information Center

    Panyr, Jiri

    1996-01-01

    Discusses object-centered knowledge representation and information retrieval. Highlights include semantic networks; frames; predicative (declarative) and associative knowledge; cluster analysis; creation of subconcepts and superconcepts; automatic classification; hierarchies and pseudohierarchies; graph theory; term classification; clustering of…

  17. A 3D interactive multi-object segmentation tool using local robust statistics driven active contours.

    PubMed

    Gao, Yi; Kikinis, Ron; Bouix, Sylvain; Shenton, Martha; Tannenbaum, Allen

    2012-08-01

    Extracting anatomical and functional significant structures renders one of the important tasks for both the theoretical study of the medical image analysis, and the clinical and practical community. In the past, much work has been dedicated only to the algorithmic development. Nevertheless, for clinical end users, a well designed algorithm with an interactive software is necessary for an algorithm to be utilized in their daily work. Furthermore, the software would better be open sourced in order to be used and validated by not only the authors but also the entire community. Therefore, the contribution of the present work is twofolds: first, we propose a new robust statistics based conformal metric and the conformal area driven multiple active contour framework, to simultaneously extract multiple targets from MR and CT medical imagery in 3D. Second, an open source graphically interactive 3D segmentation tool based on the aforementioned contour evolution is implemented and is publicly available for end users on multiple platforms. In using this software for the segmentation task, the process is initiated by the user drawn strokes (seeds) in the target region in the image. Then, the local robust statistics are used to describe the object features, and such features are learned adaptively from the seeds under a non-parametric estimation scheme. Subsequently, several active contours evolve simultaneously with their interactions being motivated by the principles of action and reaction-this not only guarantees mutual exclusiveness among the contours, but also no longer relies upon the assumption that the multiple objects fill the entire image domain, which was tacitly or explicitly assumed in many previous works. In doing so, the contours interact and converge to equilibrium at the desired positions of the desired multiple objects. Furthermore, with the aim of not only validating the algorithm and the software, but also demonstrating how the tool is to be used, we provide

  18. A 3D approach for object recognition in illuminated scenes with adaptive correlation filters

    NASA Astrophysics Data System (ADS)

    Picos, Kenia; Díaz-Ramírez, Víctor H.

    2015-09-01

    In this paper we solve the problem of pose recognition of a 3D object in non-uniformly illuminated and noisy scenes. The recognition system employs a bank of space-variant correlation filters constructed with an adaptive approach based on local statistical parameters of the input scene. The position and orientation of the target are estimated with the help of the filter bank. For an observed input frame, the algorithm computes the correlation process between the observed image and the bank of filters using a combination of data and task parallelism by taking advantage of a graphics processing unit (GPU) architecture. The pose of the target is estimated by finding the template that better matches the current view of target within the scene. The performance of the proposed system is evaluated in terms of recognition accuracy, location and orientation errors, and computational performance.

  19. Performance analysis of different surface reconstruction algorithms for 3D reconstruction of outdoor objects from their digital images.

    PubMed

    Maiti, Abhik; Chakravarty, Debashish

    2016-01-01

    3D reconstruction of geo-objects from their digital images is a time-efficient and convenient way of studying the structural features of the object being modelled. This paper presents a 3D reconstruction methodology which can be used to generate photo-realistic 3D watertight surface of different irregular shaped objects, from digital image sequences of the objects. The 3D reconstruction approach described here is robust, simplistic and can be readily used in reconstructing watertight 3D surface of any object from its digital image sequence. Here, digital images of different objects are used to build sparse, followed by dense 3D point clouds of the objects. These image-obtained point clouds are then used for generation of photo-realistic 3D surfaces, using different surface reconstruction algorithms such as Poisson reconstruction and Ball-pivoting algorithm. Different control parameters of these algorithms are identified, which affect the quality and computation time of the reconstructed 3D surface. The effects of these control parameters in generation of 3D surface from point clouds of different density are studied. It is shown that the reconstructed surface quality of Poisson reconstruction depends on Samples per node (SN) significantly, greater SN values resulting in better quality surfaces. Also, the quality of the 3D surface generated using Ball-Pivoting algorithm is found to be highly depend upon Clustering radius and Angle threshold values. The results obtained from this study give the readers of the article a valuable insight into the effects of different control parameters on determining the reconstructed surface quality. PMID:27386376

  20. OVERALL PROCEDURES PROTOCOL AND PATIENT ENROLLMENT PROTOCOL: TESTING FEASIBILITY OF 3D ULTRASOUND DATA ACQUISITION AND RELIABILITY OF DATA RETRIEVAL FROM STORED 3D IMAGES

    EPA Science Inventory

    The purpose of this study is to examine the feasibility of collecting, transmitting,

    and analyzing 3-D ultrasound data in the context of a multi-center study of pregnant

    women. The study will also examine the reliability of measurements obtained from 3-D

    imag...

  1. Ball-scale based hierarchical multi-object recognition in 3D medical images

    NASA Astrophysics Data System (ADS)

    Bağci, Ulas; Udupa, Jayaram K.; Chen, Xinjian

    2010-03-01

    This paper investigates, using prior shape models and the concept of ball scale (b-scale), ways of automatically recognizing objects in 3D images without performing elaborate searches or optimization. That is, the goal is to place the model in a single shot close to the right pose (position, orientation, and scale) in a given image so that the model boundaries fall in the close vicinity of object boundaries in the image. This is achieved via the following set of key ideas: (a) A semi-automatic way of constructing a multi-object shape model assembly. (b) A novel strategy of encoding, via b-scale, the pose relationship between objects in the training images and their intensity patterns captured in b-scale images. (c) A hierarchical mechanism of positioning the model, in a one-shot way, in a given image from a knowledge of the learnt pose relationship and the b-scale image of the given image to be segmented. The evaluation results on a set of 20 routine clinical abdominal female and male CT data sets indicate the following: (1) Incorporating a large number of objects improves the recognition accuracy dramatically. (2) The recognition algorithm can be thought as a hierarchical framework such that quick replacement of the model assembly is defined as coarse recognition and delineation itself is known as finest recognition. (3) Scale yields useful information about the relationship between the model assembly and any given image such that the recognition results in a placement of the model close to the actual pose without doing any elaborate searches or optimization. (4) Effective object recognition can make delineation most accurate.

  2. A contest of sensors in close range 3D imaging: performance evaluation with a new metric test object

    NASA Astrophysics Data System (ADS)

    Hess, M.; Robson, S.; Hosseininaveh Ahmadabadian, A.

    2014-06-01

    An independent means of 3D image quality assessment is introduced, addressing non-professional users of sensors and freeware, which is largely characterized as closed-sourced and by the absence of quality metrics for processing steps, such as alignment. A performance evaluation of commercially available, state-of-the-art close range 3D imaging technologies is demonstrated with the help of a newly developed Portable Metric Test Artefact. The use of this test object provides quality control by a quantitative assessment of 3D imaging sensors. It will enable users to give precise specifications which spatial resolution and geometry recording they expect as outcome from their 3D digitizing process. This will lead to the creation of high-quality 3D digital surrogates and 3D digital assets. The paper is presented in the form of a competition of teams, and a possible winner will emerge.

  3. The role of the foreshortening cue in the perception of 3D object slant.

    PubMed

    Ivanov, Iliya V; Kramer, Daniel J; Mullen, Kathy T

    2014-01-01

    Slant is the degree to which a surface recedes or slopes away from the observer about the horizontal axis. The perception of surface slant may be derived from static monocular cues, including linear perspective and foreshortening, applied to single shapes or to multi-element textures. It is still unclear the extent to which color vision can use these cues to determine slant in the absence of achromatic contrast. Although previous demonstrations have shown that some pictures and images may lose their depth when presented at isoluminance, this has not been tested systematically using stimuli within the spatio-temporal passband of color vision. Here we test whether the foreshortening cue from surface compression (change in the ratio of width to length) can induce slant perception for single shapes for both color and luminance vision. We use radial frequency patterns with narrowband spatio-temporal properties. In the first experiment, both a manual task (lever rotation) and a visual task (line rotation) are used as metrics to measure the perception of slant for achromatic, red-green isoluminant and S-cone isolating stimuli. In the second experiment, we measure slant discrimination thresholds as a function of depicted slant in a 2AFC paradigm and find similar thresholds for chromatic and achromatic stimuli. We conclude that both color and luminance vision can use the foreshortening of a single surface to perceive slant, with performances similar to those obtained using other strong cues for slant, such as texture. This has implications for the role of color in monocular 3D vision, and the cortical organization used in 3D object perception. PMID:24216007

  4. An objective method for 3D quality prediction using visual annoyance and acceptability level

    NASA Astrophysics Data System (ADS)

    Khaustova, Darya; Fournier, Jérôme; Wyckens, Emmanuel; Le Meur, Olivier

    2015-03-01

    This study proposes a new objective metric for video quality assessment. It predicts the impact of technical quality parameters relevant to visual discomfort on human perception. The proposed metric is based on a 3-level color scale: (1) Green - not annoying, (2) Orange - annoying but acceptable, (3) Red - not acceptable. Therefore, each color category reflects viewers' judgment based on stimulus acceptability and induced visual annoyance. The boundary between the "Green" and "Orange" categories defines the visual annoyance threshold, while the boundary between the "Orange" and "Red" categories defines the acceptability threshold. Once the technical quality parameters are measured, they are compared to perceptual thresholds. Such comparison allows estimating the quality of the 3D video sequence. Besides, the proposed metric is adjustable to service or production requirements by changing the percentage of acceptability and/or visual annoyance. The performance of the metric is evaluated in a subjective experiment that uses three stereoscopic scenes. Five view asymmetries with four degradation levels were introduced into initial test content. The results demonstrate high correlations between subjective scores and objective predictions for all view asymmetries.

  5. Object Recognition in Flight: How Do Bees Distinguish between 3D Shapes?

    PubMed

    Werner, Annette; Stürzl, Wolfgang; Zanker, Johannes

    2016-01-01

    Honeybees (Apis mellifera) discriminate multiple object features such as colour, pattern and 2D shape, but it remains unknown whether and how bees recover three-dimensional shape. Here we show that bees can recognize objects by their three-dimensional form, whereby they employ an active strategy to uncover the depth profiles. We trained individual, free flying honeybees to collect sugar water from small three-dimensional objects made of styrofoam (sphere, cylinder, cuboids) or folded paper (convex, concave, planar) and found that bees can easily discriminate between these stimuli. We also tested possible strategies employed by the bees to uncover the depth profiles. For the card stimuli, we excluded overall shape and pictorial features (shading, texture gradients) as cues for discrimination. Lacking sufficient stereo vision, bees are known to use speed gradients in optic flow to detect edges; could the bees apply this strategy also to recover the fine details of a surface depth profile? Analysing the bees' flight tracks in front of the stimuli revealed specific combinations of flight maneuvers (lateral translations in combination with yaw rotations), which are particularly suitable to extract depth cues from motion parallax. We modelled the generated optic flow and found characteristic patterns of angular displacement corresponding to the depth profiles of our stimuli: optic flow patterns from pure translations successfully recovered depth relations from the magnitude of angular displacements, additional rotation provided robust depth information based on the direction of the displacements; thus, the bees flight maneuvers may reflect an optimized visuo-motor strategy to extract depth structure from motion signals. The robustness and simplicity of this strategy offers an efficient solution for 3D-object-recognition without stereo vision, and could be employed by other flying insects, or mobile robots. PMID:26886006

  6. Object Recognition in Flight: How Do Bees Distinguish between 3D Shapes?

    PubMed Central

    Werner, Annette; Stürzl, Wolfgang; Zanker, Johannes

    2016-01-01

    Honeybees (Apis mellifera) discriminate multiple object features such as colour, pattern and 2D shape, but it remains unknown whether and how bees recover three-dimensional shape. Here we show that bees can recognize objects by their three-dimensional form, whereby they employ an active strategy to uncover the depth profiles. We trained individual, free flying honeybees to collect sugar water from small three-dimensional objects made of styrofoam (sphere, cylinder, cuboids) or folded paper (convex, concave, planar) and found that bees can easily discriminate between these stimuli. We also tested possible strategies employed by the bees to uncover the depth profiles. For the card stimuli, we excluded overall shape and pictorial features (shading, texture gradients) as cues for discrimination. Lacking sufficient stereo vision, bees are known to use speed gradients in optic flow to detect edges; could the bees apply this strategy also to recover the fine details of a surface depth profile? Analysing the bees’ flight tracks in front of the stimuli revealed specific combinations of flight maneuvers (lateral translations in combination with yaw rotations), which are particularly suitable to extract depth cues from motion parallax. We modelled the generated optic flow and found characteristic patterns of angular displacement corresponding to the depth profiles of our stimuli: optic flow patterns from pure translations successfully recovered depth relations from the magnitude of angular displacements, additional rotation provided robust depth information based on the direction of the displacements; thus, the bees flight maneuvers may reflect an optimized visuo-motor strategy to extract depth structure from motion signals. The robustness and simplicity of this strategy offers an efficient solution for 3D-object-recognition without stereo vision, and could be employed by other flying insects, or mobile robots. PMID:26886006

  7. [Method of traditional Chinese medicine formula design based on 3D-database pharmacophore search and patent retrieval].

    PubMed

    He, Yu-su; Sun, Zhi-yi; Zhang, Yan-ling

    2014-11-01

    By using the pharmacophore model of mineralocorticoid receptor antagonists as a starting point, the experiment stud- ies the method of traditional Chinese medicine formula design for anti-hypertensive. Pharmacophore models were generated by 3D-QSAR pharmacophore (Hypogen) program of the DS3.5, based on the training set composed of 33 mineralocorticoid receptor antagonists. The best pharmacophore model consisted of two Hydrogen-bond acceptors, three Hydrophobic and four excluded volumes. Its correlation coefficient of training set and test set, N, and CAI value were 0.9534, 0.6748, 2.878, and 1.119. According to the database screening, 1700 active compounds from 86 source plant were obtained. Because of lacking of available anti-hypertensive medi cation strategy in traditional theory, this article takes advantage of patent retrieval in world traditional medicine patent database, in order to design drug formula. Finally, two formulae was obtained for antihypertensive. PMID:25850277

  8. Preschoolers' Preparation for Retrieval in Object Relocation Tasks.

    ERIC Educational Resources Information Center

    Beal, Carole R.; Fleisig, Wayne E.

    The finding that young children do not prepare markers to help themselves relocate objects after a delay may have resulted from children's misunderstanding of the difficulty of unassisted retrieval. This study examined children's ability to recognize that they should prepare markers in two simplified object relocation tasks after they had been…

  9. Software for Building Models of 3D Objects via the Internet

    NASA Technical Reports Server (NTRS)

    Schramer, Tim; Jensen, Jeff

    2003-01-01

    The Virtual EDF Builder (where EDF signifies Electronic Development Fixture) is a computer program that facilitates the use of the Internet for building and displaying digital models of three-dimensional (3D) objects that ordinarily comprise assemblies of solid models created previously by use of computer-aided-design (CAD) programs. The Virtual EDF Builder resides on a Unix-based server computer. It is used in conjunction with a commercially available Web-based plug-in viewer program that runs on a client computer. The Virtual EDF Builder acts as a translator between the viewer program and a database stored on the server. The translation function includes the provision of uniform resource locator (URL) links to other Web-based computer systems and databases. The Virtual EDF builder can be used in two ways: (1) If the client computer is Unix-based, then it can assemble a model locally; the computational load is transferred from the server to the client computer. (2) Alternatively, the server can be made to build the model, in which case the server bears the computational load and the results are downloaded to the client computer or workstation upon completion.

  10. A multi-objective optimization framework to model 3D river and landscape evolution processes

    NASA Astrophysics Data System (ADS)

    Bizzi, Simone; Castelletti, Andrea; Cominola, Andrea; Mason, Emanuele; Paik, Kyungrock

    2013-04-01

    Water and sediment interactions shape hillslopes, regulate soil erosion and sedimentation, and organize river networks. Landscape evolution and river organization occur at various spatial and temporal scale and the understanding and modelling of them is highly complex. The idea of a least action principle governing river networks evolution has been proposed many times as a simpler approach among the ones existing in the literature. These theories assume that river networks, as observed in nature, self-organize and act on soil transportation in order to satisfy a particular "optimality" criterion. Accordingly, river and landscape weathering can be simulated by solving an optimization problem, where the choice of the criterion to be optimized becomes the initial assumption. The comparison between natural river networks and optimized ones verifies the correctness of this initial assumption. Yet, various criteria have been proposed in literature and there is no consensus on which is better able to explain river network features observed in nature like network branching and river bed profile: each one is able to reproduce some river features through simplified modelling of the natural processes, but it fails to characterize the whole complexity (3D and its dynamic) of the natural processes. Some of the criteria formulated in the literature partly conflict: the reason is that their formulation rely on mathematical and theoretical simplifications of the natural system that are suitable for specific spatial and temporal scale but fails to represent the whole processes characterizing landscape evolution. In an attempt to address some of these scientific questions, we tested the suitability of using a multi-objective optimization framework to describe river and landscape evolution in a 3D spatial domain. A synthetic landscape is used to this purpose. Multiple, alternative river network evolutions, corresponding to as many tradeoffs between the different and partly

  11. Ionized Outflows in 3-D Insights from Herbig-Haro Objects and Applications to Nearby AGN

    NASA Technical Reports Server (NTRS)

    Cecil, Gerald

    1999-01-01

    HST shows that the gas distributions of these objects are complex and clump at the limit of resolution. HST spectra have lumpy emission-line profiles, indicating unresolved sub-structure. The advantages of 3D over slits on gas so distributed are: robust flux estimates of various dynamical systems projected along lines of sight, sensitivity to fainter spectral lines that are physical diagnostics (reddening-gas density, T, excitation mechanisms, abundances), and improved prospects for recovery of unobserved dimensions of phase-space. These advantages al- low more confident modeling for more profound inquiry into underlying dynamics. The main complication is the effort required to link multi- frequency datasets that optimally track the energy flow through various phases of the ISM. This tedium has limited the number of objects that have been thoroughly analyzed to the a priori most spectacular systems. For HHO'S, proper-motions constrain the ambient B-field, shock velocity, gas abundances, mass-loss rates, source duty-cycle, and tie-ins with molecular flows. If the shock speed, hence ionization fraction, is indeed small then the ionized gas is a significant part of the flow energetics. For AGN'S, nuclear beaming is a source of ionization ambiguity. Establishing the energetics of the outflow is critical to determining how the accretion disk loses its energy. CXO will provide new constraints (especially spectral) on AGN outflows, and STIS UV-spectroscopy is also constraining cloud properties (although limited by extinction). HHO's show some of the things that we will find around AGN'S. I illustrate these points with results from ground-based and HST programs being pursued with collaborators.

  12. New 3D thermal evolution model for icy bodies application to trans-Neptunian objects

    NASA Astrophysics Data System (ADS)

    Guilbert-Lepoutre, A.; Lasue, J.; Federico, C.; Coradini, A.; Orosei, R.; Rosenberg, E. D.

    2011-05-01

    Context. Thermal evolution models have been developed over the years to investigate the evolution of thermal properties based on the transfer of heat fluxes or transport of gas through a porous matrix, among others. Applications of such models to trans-Neptunian objects (TNOs) and Centaurs has shown that these bodies could be strongly differentiated from the point of view of chemistry (i.e. loss of most volatile ices), as well as from physics (e.g. melting of water ice), resulting in stratified internal structures with differentiated cores and potential pristine material close to the surface. In this context, some observational results, such as the detection of crystalline water ice or volatiles, remain puzzling. Aims: In this paper, we would like to present a new fully three-dimensional thermal evolution model. With this model, we aim to improve determination of the temperature distribution inside icy bodies such as TNOs by accounting for lateral heat fluxes, which have been proven to be important for accurate simulations. We also would like to be able to account for heterogeneous boundary conditions at the surface through various albedo properties, for example, that might induce different local temperature distributions. Methods: In a departure from published modeling approaches, the heat diffusion problem and its boundary conditions are represented in terms of real spherical harmonics, increasing the numerical efficiency by roughly an order of magnitude. We then compare this new model and another 3D model recently published to illustrate the advantages and limits of the new model. We try to put some constraints on the presence of crystalline water ice at the surface of TNOs. Results: The results obtained with this new model are in excellent agreement with results obtained by different groups with various models. Small TNOs could remain primitive unless they are formed quickly (less than 2 Myr) or are debris from the disruption of larger bodies. We find that, for

  13. 3D models automatic reconstruction of selected close range objects. (Polish Title: Automatyczna rekonstrukcja modeli 3D małych obiektów bliskiego zasiegu)

    NASA Astrophysics Data System (ADS)

    Zaweiska, D.

    2013-12-01

    Reconstruction of three-dimensional, realistic models of objects from digital images has been the topic of research in many areas of science for many years. This development is stimulated by new technologies and tools, which appeared recently, such as digital photography, laser scanners, increase in the equipment efficiency and Internet. The objective of this paper is to present results of automatic modeling of selected close range objects, with the use of digital photographs acquired by the Hasselblad H4D50 camera. The author's software tool was utilized for calculations; it performs successive stages of the 3D model creation. The modeling process was presented as the complete process which starts from acquisition of images and which is completed by creation of a photorealistic 3D model in the same software environment. Experiments were performed for selected close range objects, with appropriately arranged image geometry, creating a ring around the measured object. The Area Base Matching (CC/LSM) method, the RANSAC algorithm, with the use of tensor calculus, were utilized form automatic matching of points detected with the SUSAN algorithm. Reconstruction of the surface of model generation is one of the important stages of 3D modeling. Reconstruction of precise surfaces, performed on the basis of a non-organized cloud of points, acquired from automatic processing of digital images, is a difficult task, which has not been finally solved. Creation of poly-angular models, which may meet high requirements concerning modeling and visualization is required in many applications. The polynomial method is usually the best way to precise representation of measurement results, and, at the same time, to achieving the optimum description of the surface. Three algorithm were tested: the volumetric method (VCG), the Poisson method and the Ball pivoting method. Those methods are mostly applied to modeling of uniform grids of points. Results of experiments proved that incorrect

  14. True-3D Accentuating of Grids and Streets in Urban Topographic Maps Enhances Human Object Location Memory

    PubMed Central

    Edler, Dennis; Bestgen, Anne-Kathrin; Kuchinke, Lars; Dickmann, Frank

    2015-01-01

    Cognitive representations of learned map information are subject to systematic distortion errors. Map elements that divide a map surface into regions, such as content-related linear symbols (e.g. streets, rivers, railway systems) or additional artificial layers (coordinate grids), provide an orientation pattern that can help users to reduce distortions in their mental representations. In recent years, the television industry has started to establish True-3D (autostereoscopic) displays as mass media. These modern displays make it possible to watch dynamic and static images including depth illusions without additional devices, such as 3D glasses. In these images, visual details can be distributed over different positions along the depth axis. Some empirical studies of vision research provided first evidence that 3D stereoscopic content attracts higher attention and is processed faster. So far, the impact of True-3D accentuating has not yet been explored concerning spatial memory tasks and cartography. This paper reports the results of two empirical studies that focus on investigations whether True-3D accentuating of artificial, regular overlaying line features (i.e. grids) and content-related, irregular line features (i.e. highways and main streets) in official urban topographic maps (scale 1/10,000) further improves human object location memory performance. The memory performance is measured as both the percentage of correctly recalled object locations (hit rate) and the mean distances of correctly recalled objects (spatial accuracy). It is shown that the True-3D accentuating of grids (depth offset: 5 cm) significantly enhances the spatial accuracy of recalled map object locations, whereas the True-3D emphasis of streets significantly improves the hit rate of recalled map object locations. These results show the potential of True-3D displays for an improvement of the cognitive representation of learned cartographic information. PMID:25679208

  15. True-3D accentuating of grids and streets in urban topographic maps enhances human object location memory.

    PubMed

    Edler, Dennis; Bestgen, Anne-Kathrin; Kuchinke, Lars; Dickmann, Frank

    2015-01-01

    Cognitive representations of learned map information are subject to systematic distortion errors. Map elements that divide a map surface into regions, such as content-related linear symbols (e.g. streets, rivers, railway systems) or additional artificial layers (coordinate grids), provide an orientation pattern that can help users to reduce distortions in their mental representations. In recent years, the television industry has started to establish True-3D (autostereoscopic) displays as mass media. These modern displays make it possible to watch dynamic and static images including depth illusions without additional devices, such as 3D glasses. In these images, visual details can be distributed over different positions along the depth axis. Some empirical studies of vision research provided first evidence that 3D stereoscopic content attracts higher attention and is processed faster. So far, the impact of True-3D accentuating has not yet been explored concerning spatial memory tasks and cartography. This paper reports the results of two empirical studies that focus on investigations whether True-3D accentuating of artificial, regular overlaying line features (i.e. grids) and content-related, irregular line features (i.e. highways and main streets) in official urban topographic maps (scale 1/10,000) further improves human object location memory performance. The memory performance is measured as both the percentage of correctly recalled object locations (hit rate) and the mean distances of correctly recalled objects (spatial accuracy). It is shown that the True-3D accentuating of grids (depth offset: 5 cm) significantly enhances the spatial accuracy of recalled map object locations, whereas the True-3D emphasis of streets significantly improves the hit rate of recalled map object locations. These results show the potential of True-3D displays for an improvement of the cognitive representation of learned cartographic information. PMID:25679208

  16. Automatic object extraction over multiscale edge field for multimedia retrieval.

    PubMed

    Kiranyaz, Serkan; Ferreira, Miguel; Gabbouj, Moncef

    2006-12-01

    In this work, we focus on automatic extraction of object boundaries from Canny edge field for the purpose of content-based indexing and retrieval over image and video databases. A multiscale approach is adopted where each successive scale provides further simplification of the image by removing more details, such as texture and noise, while keeping major edges. At each stage of the simplification, edges are extracted from the image and gathered in a scale-map, over which a perceptual subsegment analysis is performed in order to extract true object boundaries. The analysis is mainly motivated by Gestalt laws and our experimental results suggest a promising performance for main objects extraction, even for images with crowded textural edges and objects with color, texture, and illumination variations. Finally, integrating the whole process as feature extraction module into MUVIS framework allows us to test the mutual performance of the proposed object extraction method and subsequent shape description in the context of multimedia indexing and retrieval. A promising retrieval performance is achieved, and especially in some particular examples, the experimental results show that the proposed method presents such a retrieval performance that cannot be achieved by using other features such as color or texture. PMID:17153949

  17. Phase retrieval-based distribution detecting method for transparent objects

    NASA Astrophysics Data System (ADS)

    Wu, Liang; Tao, Shaohua; Xiao, Si

    2015-11-01

    A distribution detecting method to recover the distribution of transparent objects from their diffraction intensities is proposed. First, on the basis of the Gerchberg-Saxton algorithm, a wavefront function involving the phase change of the object is retrieved from the incident light intensity and the diffraction intensity, then the phase change of the object is calculated from the retrieved wavefront function by using a gradient field-based phase estimation algorithm, which circumvents the common phase wrapping problem. Finally, a linear model between the distribution of the object and the phase change is set up, and the distribution of the object can be calculated from the obtained phase change. The effectiveness of the proposed method is verified with simulations and experiments.

  18. Laser Transfer of Metals and Metal Alloys for Digital Microfabrication of 3D Objects.

    PubMed

    Zenou, Michael; Sa'ar, Amir; Kotler, Zvi

    2015-09-01

    3D copper logos printed on epoxy glass laminates are demonstrated. The structures are printed using laser transfer of molten metal microdroplets. The example in the image shows letters of 50 µm width, with each letter being taller than the last, from a height of 40 µm ('s') to 190 µm ('l'). The scanning microscopy image is taken at a tilt, and the topographic image was taken using interferometric 3D microscopy, to show the effective control of this technique. PMID:25966320

  19. The effect of object speed and direction on the performance of 3D speckle tracking using a 3D swept-volume ultrasound probe

    NASA Astrophysics Data System (ADS)

    Harris, Emma J.; Miller, Naomi R.; Bamber, Jeffrey C.; Symonds-Tayler, J. Richard N.; Evans, Philip M.

    2011-11-01

    Three-dimensional (3D) soft tissue tracking using 3D ultrasound is of interest for monitoring organ motion during therapy. Previously we demonstrated feature tracking of respiration-induced liver motion in vivo using a 3D swept-volume ultrasound probe. The aim of this study was to investigate how object speed affects the accuracy of tracking ultrasonic speckle in the absence of any structural information, which mimics the situation in homogenous tissue for motion in the azimuthal and elevational directions. For object motion prograde and retrograde to the sweep direction of the transducer, the spatial sampling frequency increases or decreases with object speed, respectively. We examined the effect object motion direction of the transducer on tracking accuracy. We imaged a homogenous ultrasound speckle phantom whilst moving the probe with linear motion at a speed of 0-35 mm s-1. Tracking accuracy and precision were investigated as a function of speed, depth and direction of motion for fixed displacements of 2 and 4 mm. For the azimuthal direction, accuracy was better than 0.1 and 0.15 mm for displacements of 2 and 4 mm, respectively. For a 2 mm displacement in the elevational direction, accuracy was better than 0.5 mm for most speeds. For 4 mm elevational displacement with retrograde motion, accuracy and precision reduced with speed and tracking failure was observed at speeds of greater than 14 mm s-1. Tracking failure was attributed to speckle de-correlation as a result of decreasing spatial sampling frequency with increasing speed of retrograde motion. For prograde motion, tracking failure was not observed. For inter-volume displacements greater than 2 mm, only prograde motion should be tracked which will decrease temporal resolution by a factor of 2. Tracking errors of the order of 0.5 mm for prograde motion in the elevational direction indicates that using the swept probe technology speckle tracking accuracy is currently too poor to track homogenous tissue over

  20. Affective SSVEP BCI to effectively control 3D objects by using a prism array-based display

    NASA Astrophysics Data System (ADS)

    Mun, Sungchul; Park, Min-Chul

    2014-06-01

    3D objects with depth information can provide many benefits to users in education, surgery, and interactions. In particular, many studies have been done to enhance sense of reality in 3D interaction. Viewing and controlling stereoscopic 3D objects with crossed or uncrossed disparities, however, can cause visual fatigue due to the vergenceaccommodation conflict generally accepted in 3D research fields. In order to avoid the vergence-accommodation mismatch and provide a strong sense of presence to users, we apply a prism array-based display to presenting 3D objects. Emotional pictures were used as visual stimuli in control panels to increase information transfer rate and reduce false positives in controlling 3D objects. Involuntarily motivated selective attention by affective mechanism can enhance steady-state visually evoked potential (SSVEP) amplitude and lead to increased interaction efficiency. More attentional resources are allocated to affective pictures with high valence and arousal levels than to normal visual stimuli such as white-and-black oscillating squares and checkerboards. Among representative BCI control components (i.e., eventrelated potentials (ERP), event-related (de)synchronization (ERD/ERS), and SSVEP), SSVEP-based BCI was chosen in the following reasons. It shows high information transfer rates and takes a few minutes for users to control BCI system while few electrodes are required for obtaining reliable brainwave signals enough to capture users' intention. The proposed BCI methods are expected to enhance sense of reality in 3D space without causing critical visual fatigue to occur. In addition, people who are very susceptible to (auto) stereoscopic 3D may be able to use the affective BCI.

  1. 3-D ion distribution and evolution in storm-time RC Retrieved from TWINS ENA by differential voxel CT technique

    NASA Astrophysics Data System (ADS)

    Ma, S.; Yan, W.; Xu, L.

    2013-12-01

    The quantitative retrieval of the 3-D spatial distribution of the parent energetic ions of ENA from a 2-D ENA image is a quite challenge task. The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission of NASA is the first constellation to perform stereoscopic magnetospheric imaging of energetic neutral atoms (ENA) from a pair of spacecraft flying on two widely-separated Molniya orbits. TWINS provides a unique opportunity to retrieve the 3-D distribution of ions in the ring current (RC) by using a volumetric pixel (voxel) CT inversion method. In this study the voxel CT method is implemented for a series of differential ENA fluxes averaged over about 6 to 7 sweeps (corresponding to a time period of about 9 min.) at different energy levels ranging from 5 to 100 keV, obtained simultaneously by the two satellites during the main phase of a great magnetic storm with minimum Sym-H of -156 nT on 24-25 October 2011. The data were selected to span a period about 50 minutes during which a large substorm was undergoing its expansion phase first and then recovery. The ENA species of O and H are distinguished for some time-segments by analyzing the signals of pulse heights of second electrons emitted from the carbon foil and impacted on the MCP detector in the TWINS sensors. In order to eliminate the possible influence on retrieval induced by instrument bias error, a differential voxel CT technique is applied. The flux intensity of the ENAs' parent ions in the RC has been obtained as a function of energy, L value, MLT sector and latitude, along with their time evolution during the storm-time substorm expansion phase. Forward calculations proved the reliability of the retrieved results. It shows that the RC is highly asymmetric, with a major concentration in the midnight to dawn sector for equatorial latitudes. Halfway through the substorm expansion there occurred a large enhancement of equatorial ion flux at lower energy (5 keV) in the dusk sector, with narrow extent

  2. Visualizing 3D Objects from 2D Cross Sectional Images Displayed "In-Situ" versus "Ex-Situ"

    ERIC Educational Resources Information Center

    Wu, Bing; Klatzky, Roberta L.; Stetten, George

    2010-01-01

    The present research investigates how mental visualization of a 3D object from 2D cross sectional images is influenced by displacing the images from the source object, as is customary in medical imaging. Three experiments were conducted to assess people's ability to integrate spatial information over a series of cross sectional images in order to…

  3. Mobile object retrieval in server-based image databases

    NASA Astrophysics Data System (ADS)

    Manger, D.; Pagel, F.; Widak, H.

    2013-05-01

    The increasing number of mobile phones equipped with powerful cameras leads to huge collections of user-generated images. To utilize the information of the images on site, image retrieval systems are becoming more and more popular to search for similar objects in an own image database. As the computational performance and the memory capacity of mobile devices are constantly increasing, this search can often be performed on the device itself. This is feasible, for example, if the images are represented with global image features or if the search is done using EXIF or textual metadata. However, for larger image databases, if multiple users are meant to contribute to a growing image database or if powerful content-based image retrieval methods with local features are required, a server-based image retrieval backend is needed. In this work, we present a content-based image retrieval system with a client server architecture working with local features. On the server side, the scalability to large image databases is addressed with the popular bag-of-word model with state-of-the-art extensions. The client end of the system focuses on a lightweight user interface presenting the most similar images of the database highlighting the visual information which is common with the query image. Additionally, new images can be added to the database making it a powerful and interactive tool for mobile contentbased image retrieval.

  4. Fast large-scale object retrieval with binary quantization

    NASA Astrophysics Data System (ADS)

    Zhou, Shifu; Zeng, Dan; Shen, Wei; Zhang, Zhijiang; Tian, Qi

    2015-11-01

    The objective of large-scale object retrieval systems is to search for images that contain the target object in an image database. Where state-of-the-art approaches rely on global image representations to conduct searches, we consider many boxes per image as candidates to search locally in a picture. In this paper, a feature quantization algorithm called binary quantization is proposed. In binary quantization, a scale-invariant feature transform (SIFT) feature is quantized into a descriptive and discriminative bit-vector, which allows itself to adapt to the classic inverted file structure for box indexing. The inverted file, which stores the bit-vector and box ID where the SIFT feature is located inside, is compact and can be loaded into the main memory for efficient box indexing. We evaluate our approach on available object retrieval datasets. Experimental results demonstrate that the proposed approach is fast and achieves excellent search quality. Therefore, the proposed approach is an improvement over state-of-the-art approaches for object retrieval.

  5. Simulated and Real Sheet-of-Light 3D Object Scanning Using a-Si:H Thin Film PSD Arrays

    PubMed Central

    Contreras, Javier; Tornero, Josep; Ferreira, Isabel; Martins, Rodrigo; Gomes, Luis; Fortunato, Elvira

    2015-01-01

    A MATLAB/SIMULINK software simulation model (structure and component blocks) has been constructed in order to view and analyze the potential of the PSD (Position Sensitive Detector) array concept technology before it is further expanded or developed. This simulation allows changing most of its parameters, such as the number of elements in the PSD array, the direction of vision, the viewing/scanning angle, the object rotation, translation, sample/scan/simulation time, etc. In addition, results show for the first time the possibility of scanning an object in 3D when using an a-Si:H thin film 128 PSD array sensor and hardware/software system. Moreover, this sensor technology is able to perform these scans and render 3D objects at high speeds and high resolutions when using a sheet-of-light laser within a triangulation platform. As shown by the simulation, a substantial enhancement in 3D object profile image quality and realism can be achieved by increasing the number of elements of the PSD array sensor as well as by achieving an optimal position response from the sensor since clearly the definition of the 3D object profile depends on the correct and accurate position response of each detector as well as on the size of the PSD array. PMID:26633403

  6. Simulated and Real Sheet-of-Light 3D Object Scanning Using a-Si:H Thin Film PSD Arrays.

    PubMed

    Contreras, Javier; Tornero, Josep; Ferreira, Isabel; Martins, Rodrigo; Gomes, Luis; Fortunato, Elvira

    2015-01-01

    A MATLAB/SIMULINK software simulation model (structure and component blocks) has been constructed in order to view and analyze the potential of the PSD (Position Sensitive Detector) array concept technology before it is further expanded or developed. This simulation allows changing most of its parameters, such as the number of elements in the PSD array, the direction of vision, the viewing/scanning angle, the object rotation, translation, sample/scan/simulation time, etc. In addition, results show for the first time the possibility of scanning an object in 3D when using an a-Si:H thin film 128 PSD array sensor and hardware/software system. Moreover, this sensor technology is able to perform these scans and render 3D objects at high speeds and high resolutions when using a sheet-of-light laser within a triangulation platform. As shown by the simulation, a substantial enhancement in 3D object profile image quality and realism can be achieved by increasing the number of elements of the PSD array sensor as well as by achieving an optimal position response from the sensor since clearly the definition of the 3D object profile depends on the correct and accurate position response of each detector as well as on the size of the PSD array. PMID:26633403

  7. A Comparative Analysis between Active and Passive Techniques for Underwater 3D Reconstruction of Close-Range Objects

    PubMed Central

    Bianco, Gianfranco; Gallo, Alessandro; Bruno, Fabio; Muzzupappa, Maurizio

    2013-01-01

    In some application fields, such as underwater archaeology or marine biology, there is the need to collect three-dimensional, close-range data from objects that cannot be removed from their site. In particular, 3D imaging techniques are widely employed for close-range acquisitions in underwater environment. In this work we have compared in water two 3D imaging techniques based on active and passive approaches, respectively, and whole-field acquisition. The comparison is performed under poor visibility conditions, produced in the laboratory by suspending different quantities of clay in a water tank. For a fair comparison, a stereo configuration has been adopted for both the techniques, using the same setup, working distance, calibration, and objects. At the moment, the proposed setup is not suitable for real world applications, but it allowed us to conduct a preliminary analysis on the performances of the two techniques and to understand their capability to acquire 3D points in presence of turbidity. The performances have been evaluated in terms of accuracy and density of the acquired 3D points. Our results can be used as a reference for further comparisons in the analysis of other 3D techniques and algorithms. PMID:23966193

  8. A comparative analysis between active and passive techniques for underwater 3D reconstruction of close-range objects.

    PubMed

    Bianco, Gianfranco; Gallo, Alessandro; Bruno, Fabio; Muzzupappa, Maurizio

    2013-01-01

    In some application fields, such as underwater archaeology or marine biology, there is the need to collect three-dimensional, close-range data from objects that cannot be removed from their site. In particular, 3D imaging techniques are widely employed for close-range acquisitions in underwater environment. In this work we have compared in water two 3D imaging techniques based on active and passive approaches, respectively, and whole-field acquisition. The comparison is performed under poor visibility conditions, produced in the laboratory by suspending different quantities of clay in a water tank. For a fair comparison, a stereo configuration has been adopted for both the techniques, using the same setup, working distance, calibration, and objects. At the moment, the proposed setup is not suitable for real world applications, but it allowed us to conduct a preliminary analysis on the performances of the two techniques and to understand their capability to acquire 3D points in presence of turbidity. The performances have been evaluated in terms of accuracy and density of the acquired 3D points. Our results can be used as a reference for further comparisons in the analysis of other 3D techniques and algorithms. PMID:23966193

  9. Development of 3D interactive visual objects using the Scripps Institution of Oceanography's Visualization Center

    NASA Astrophysics Data System (ADS)

    Kilb, D.; Reif, C.; Peach, C.; Keen, C. S.; Smith, B.; Mellors, R. J.

    2003-12-01

    Within the last year scientists and educators at the Scripps Institution of Oceanography (SIO), the Birch Aquarium at Scripps and San Diego State University have collaborated with education specialists to develop 3D interactive graphic teaching modules for use in the classroom and in teacher workshops at the SIO Visualization center (http://siovizcenter.ucsd.edu). The unique aspect of the SIO Visualization center is that the center is designed around a 120 degree curved Panoram floor-to-ceiling screen (8'6" by 28'4") that immerses viewers in a virtual environment. The center is powered by an SGI 3400 Onyx computer that is more powerful, by an order of magnitude in both speed and memory, than typical base systems currently used for education and outreach presentations. This technology allows us to display multiple 3D data layers (e.g., seismicity, high resolution topography, seismic reflectivity, draped interferometric synthetic aperture radar (InSAR) images, etc.) simultaneously, render them in 3D stereo, and take a virtual flight through the data as dictated on the spot by the user. This system can also render snapshots, images and movies that are too big for other systems, and then export smaller size end-products to more commonly used computer systems. Since early 2002, we have explored various ways to provide informal education and outreach focusing on current research presented directly by the researchers doing the work. The Center currently provides a centerpiece for instruction on southern California seismology for K-12 students and teachers for various Scripps education endeavors. Future plans are in place to use the Visualization Center at Scripps for extended K-12 and college educational programs. In particular, we will be identifying K-12 curriculum needs, assisting with teacher education, developing assessments of our programs and products, producing web-accessible teaching modules and facilitating the development of appropriate teaching tools to be

  10. Flying triangulation - A motion-robust optical 3D sensor for the real-time shape acquisition of complex objects

    NASA Astrophysics Data System (ADS)

    Willomitzer, Florian; Ettl, Svenja; Arold, Oliver; Häusler, Gerd

    2013-05-01

    The three-dimensional shape acquisition of objects has become more and more important in the last years. Up to now, there are several well-established methods which already yield impressive results. However, even under quite common conditions like object movement or a complex shaping, most methods become unsatisfying. Thus, the 3D shape acquisition is still a difficult and non-trivial task. We present our measurement principle "Flying Triangulation" which enables a motion-robust 3D acquisition of complex-shaped object surfaces by a freely movable handheld sensor. Since "Flying Triangulation" is scalable, a whole sensor-zoo for different object sizes is presented. Concluding, an overview of current and future fields of investigation is given.

  11. Progress in Understanding the Impacts of 3-D Cloud Structure on MODIS Cloud Property Retrievals for Marine Boundary Layer Clouds

    NASA Technical Reports Server (NTRS)

    Zhang, Zhibo; Werner, Frank; Miller, Daniel; Platnick, Steven; Ackerman, Andrew; DiGirolamo, Larry; Meyer, Kerry; Marshak, Alexander; Wind, Galina; Zhao, Guangyu

    2016-01-01

    Theory: A novel framework based on 2-D Tayler expansion for quantifying the uncertainty in MODIS retrievals caused by sub-pixel reflectance inhomogeneity. (Zhang et al. 2016). How cloud vertical structure influences MODIS LWP retrievals. (Miller et al. 2016). Observation: Analysis of failed MODIS cloud property retrievals. (Cho et al. 2015). Cloud property retrievals from 15m resolution ASTER observations. (Werner et al. 2016). Modeling: LES-Satellite observation simulator (Zhang et al. 2012, Miller et al. 2016).

  12. Eccentricity in Images of Circular and Spherical Targets and its Impact to 3D Object Reconstruction

    NASA Astrophysics Data System (ADS)

    Luhmann, T.

    2014-06-01

    This paper discusses a feature of projective geometry which causes eccentricity in the image measurement of circular and spherical targets. While it is commonly known that flat circular targets can have a significant displacement of the elliptical image centre with respect to the true imaged circle centre, it can also be shown that the a similar effect exists for spherical targets. Both types of targets are imaged with an elliptical contour. As a result, if measurement methods based on ellipses are used to detect the target (e.g. best-fit ellipses), the calculated ellipse centre does not correspond to the desired target centre in 3D space. This paper firstly discusses the use and measurement of circular and spherical targets. It then describes the geometrical projection model in order to demonstrate the eccentricity in image space. Based on numerical simulations, the eccentricity in the image is further quantified and investigated. Finally, the resulting effect in 3D space is estimated for stereo and multi-image intersections. It can be stated that the eccentricity is larger than usually assumed, and must be compensated for high-accuracy applications. Spherical targets do not show better results than circular targets. The paper is an updated version of Luhmann (2014) new experimental investigations on the effect of length measurement errors.

  13. Evaluation of iterative sparse object reconstruction from few projections for 3-D rotational coronary angiography.

    PubMed

    Hansis, Eberhard; Schäfer, Dirk; Dössel, Olaf; Grass, Michael

    2008-11-01

    A 3-D reconstruction of the coronary arteries offers great advantages in the diagnosis and treatment of cardiovascular disease, compared to 2-D X-ray angiograms. Besides improved roadmapping, quantitative vessel analysis is possible. Due to the heart's motion, rotational coronary angiography typically provides only 5-10 projections for the reconstruction of each cardiac phase, which leads to a strongly undersampled reconstruction problem. Such an ill-posed problem can be approached with regularized iterative methods. The coronary arteries cover only a small fraction of the reconstruction volume. Therefore, the minimization of the mbiL(1) norm of the reconstructed image, favoring spatially sparse images, is a suitable regularization. Additional problems are overlaid background structures and projection truncation, which can be alleviated by background reduction using a morphological top-hat filter. This paper quantitatively evaluates image reconstruction based on these ideas on software phantom data, in terms of reconstructed absorption coefficients and vessel radii. Results for different algorithms and different input data sets are compared. First results for electrocardiogram-gated reconstruction from clinical catheter-based rotational X-ray coronary angiography are presented. Excellent 3-D image quality can be achieved. PMID:18955171

  14. Influence of georeference for saturated excess overland flow modelling using 3D volumetric soft geo-objects

    NASA Astrophysics Data System (ADS)

    Izham, Mohamad Yusoff; Muhamad Uznir, Ujang; Alias, Abdul Rahman; Ayob, Katimon; Wan Ruslan, Ismail

    2011-04-01

    Existing 2D data structures are often insufficient for analysing the dynamism of saturation excess overland flow (SEOF) within a basin. Moreover, all stream networks and soil surface structures in GIS must be preserved within appropriate projection plane fitting techniques known as georeferencing. Inclusion of 3D volumetric structure of the current soft geo-objects simulation model would offer a substantial effort towards representing 3D soft geo-objects of SEOF dynamically within a basin by visualising saturated flow and overland flow volume. This research attempts to visualise the influence of a georeference system towards the dynamism of overland flow coverage and total overland flow volume generated from the SEOF process using VSG data structure. The data structure is driven by Green-Ampt methods and the Topographic Wetness Index (TWI). VSGs are analysed by focusing on spatial object preservation techniques of the conformal-based Malaysian Rectified Skew Orthomorphic (MRSO) and the equidistant-based Cassini-Soldner projection plane under the existing geodetic Malaysian Revised Triangulation 1948 (MRT48) and the newly implemented Geocentric Datum for Malaysia (GDM2000) datum. The simulated result visualises deformation of SEOF coverage under different georeference systems via its projection planes, which delineate dissimilar computation of SEOF areas and overland flow volumes. The integration of Georeference, 3D GIS and the saturation excess mechanism provides unifying evidence towards successful landslide and flood disaster management through envisioning the streamflow generating process (mainly SEOF) in a 3D environment.

  15. 3D phase micro-object studies by means of digital holographic tomography supported by algebraic reconstruction technique

    NASA Astrophysics Data System (ADS)

    Bilski, B. J.; Jozwicka, A.; Kujawinska, M.

    2007-09-01

    Constant development of microelements' technology requires a creation of new instruments to determine their basic physical parameters in 3D. The most efficient non-destructive method providing 3D information is tomography. In this paper we present Digital Holographic Tomography (DHT), in which input data is provided by means of Di-git- al Holography (DH). The main advantage of DH is the capability to capture several projections with a single hologram [1]. However, these projections have uneven angular distribution and their number is significantly limited. Therefore - Algebraic Reconstruction Technique (ART), where a few phase projections may be sufficient for proper 3D phase reconstruction, is implemented. The error analysis of the method and its additional limitations due to shape and dimensions of investigated object are presented. Finally, the results of ART application to DHT method are also presented on data reconstructed from numerically generated hologram of a multimode fibre.

  16. 3D GeoWall Analysis System for Shuttle External Tank Foreign Object Debris Events

    NASA Technical Reports Server (NTRS)

    Brown, Richard; Navard, Andrew; Spruce, Joseph

    2010-01-01

    An analytical, advanced imaging method has been developed for the initial monitoring and identification of foam debris and similar anomalies that occur post-launch in reference to the space shuttle s external tank (ET). Remote sensing technologies have been used to perform image enhancement and analysis on high-resolution, true-color images collected with the DCS 760 Kodak digital camera located in the right umbilical well of the space shuttle. Improvements to the camera, using filters, have added sharpness/definition to the image sets; however, image review/analysis of the ET has been limited by the fact that the images acquired by umbilical cameras during launch are two-dimensional, and are usually nonreferenceable between frames due to rotation translation of the ET as it falls away from the space shuttle. Use of stereo pairs of these images can enable strong visual indicators that can immediately portray depth perception of damaged areas or movement of fragments between frames is not perceivable in two-dimensional images. A stereoscopic image visualization system has been developed to allow 3D depth perception of stereo-aligned image pairs taken from in-flight umbilical and handheld digital shuttle cameras. This new system has been developed to augment and optimize existing 2D monitoring capabilities. Using this system, candidate sequential image pairs are identified for transformation into stereo viewing pairs. Image orientation is corrected using control points (similar points) between frames to place the two images in proper X-Y viewing perspective. The images are then imported into the WallView stereo viewing software package. The collected control points are used to generate a transformation equation that is used to re-project one image and effectively co-register it to the other image. The co-registered, oriented image pairs are imported into a WallView image set and are used as a 3D stereo analysis slide show. Multiple sequential image pairs can be used

  17. A stroboscopic structured illumination system used in dynamic 3D visualization of high-speed motion object

    NASA Astrophysics Data System (ADS)

    Su, Xianyu; Zhang, Qican; Li, Yong; Xiang, Liqun; Cao, Yiping; Chen, Wenjing

    2005-04-01

    A stroboscopic structured illumination system, which can be used in measurement for 3D shape and deformation of high-speed motion object, is proposed and verified by experiments. The system, present in this paper, can automatically detect the position of high-speed moving object and synchronously control the flash of LED to project a structured optical field onto surface of motion object and the shoot of imaging system to acquire an image of deformed fringe pattern, also can create a signal, set artificially through software, to synchronously control the LED and imaging system to do their job. We experiment on a civil electric fan, successful acquire a serial of instantaneous, sharp and clear images of rotation blade and reconstruct its 3D shapes in difference revolutions.

  18. VIRO 3D: fast three-dimensional full-body scanning for humans and other living objects

    NASA Astrophysics Data System (ADS)

    Stein, Norbert; Minge, Bernhard

    1998-03-01

    The development of a family of partial and whole body scanners provides a complete technology for fully three-dimensional and contact-free scans on human bodies or other living objects within seconds. This paper gives insight into the design and the functional principles of the whole body scanner VIRO 3D operating on the basis of the laser split-beam method. The arrangement of up to 24 camera/laser combinations, thus dividing the area into different camera fields and an all- around sensor configuration travelling in vertical direction allow the complete 360-degree-scan of an object within 6 - 20 seconds. Due to a special calibration process the different sensors are matched and the measured data are combined. Up to 10 million 3D measuring points with a resolution of approximately 1 mm are processed in all coordinate axes to generate a 3D model. By means of high-performance processors in combination with real-time image processing chips the image data from almost any number of sensors can be recorded and evaluated synchronously in video real-time. VIRO 3D scanning systems have already been successfully implemented in various applications and will open up new perspectives in different other fields, ranging from industry, orthopaedic medicine, plastic surgery to art and photography.

  19. The dorsal stream contribution to phonological retrieval in object naming

    PubMed Central

    Faseyitan, Olufunsho; Kim, Junghoon; Coslett, H. Branch

    2012-01-01

    Meaningful speech, as exemplified in object naming, calls on knowledge of the mappings between word meanings and phonological forms. Phonological errors in naming (e.g. GHOST named as ‘goath’) are commonly seen in persisting post-stroke aphasia and are thought to signal impairment in retrieval of phonological form information. We performed a voxel-based lesion-symptom mapping analysis of 1718 phonological naming errors collected from 106 individuals with diverse profiles of aphasia. Voxels in which lesion status correlated with phonological error rates localized to dorsal stream areas, in keeping with classical and contemporary brain-language models. Within the dorsal stream, the critical voxels were concentrated in premotor cortex, pre- and postcentral gyri and supramarginal gyrus with minimal extension into auditory-related posterior temporal and temporo-parietal cortices. This challenges the popular notion that error-free phonological retrieval requires guidance from sensory traces stored in posterior auditory regions and points instead to sensory-motor processes located further anterior in the dorsal stream. In a separate analysis, we compared the lesion maps for phonological and semantic errors and determined that there was no spatial overlap, demonstrating that the brain segregates phonological and semantic retrieval operations in word production. PMID:23171662

  20. Evaluation methods for retrieving information from interferograms of biomedical objects

    NASA Astrophysics Data System (ADS)

    Podbielska, Halina; Rottenkolber, Matthias

    1996-04-01

    Interferograms in the form of fringe patterns can be produced in two-beam interferometers, holographic or speckle interferometers, in setups realizing moire techniques or in deflectometers. Optical metrology based on the principle of interference can be applied as a testing tool in biomedical research. By analyzing of the fringe pattern images, information about the shape or mechanical behavior of the object under study can be retrieved. Here, some of the techniques for creating fringe pattern images were presented along with methods of analysis. Intensity based analysis as well as methods of phase measurements, are mentioned. Applications of inteferometric methods, especially in the field of experimental orthopedics, endoscopy and ophthalmology are pointed out.

  1. A fast 3-D object recognition algorithm for the vision system of a special-purpose dexterous manipulator

    NASA Technical Reports Server (NTRS)

    Hung, Stephen H. Y.

    1989-01-01

    A fast 3-D object recognition algorithm that can be used as a quick-look subsystem to the vision system for the Special-Purpose Dexterous Manipulator (SPDM) is described. Global features that can be easily computed from range data are used to characterize the images of a viewer-centered model of an object. This algorithm will speed up the processing by eliminating the low level processing whenever possible. It may identify the object, reject a set of bad data in the early stage, or create a better environment for a more powerful algorithm to carry the work further.

  2. 3D scene's object detection and recognition using depth layers and SIFT-based machine learning

    NASA Astrophysics Data System (ADS)

    Kounalakis, T.; Triantafyllidis, G. A.

    2011-09-01

    This paper presents a novel system that is fusing efficient and state-of-the-art techniques of stereo vision and machine learning, aiming at object detection and recognition. To this goal, the system initially creates depth maps by employing the Graph-Cut technique. Then, the depth information is used for object detection by separating the objects from the whole scene. Next, the Scale-Invariant Feature Transform (SIFT) is used, providing the system with unique object's feature key-points, which are employed in training an Artificial Neural Network (ANN). The system is then able to classify and recognize the nature of these objects, creating knowledge from the real world. [Figure not available: see fulltext.

  3. Controlled Experimental Study Depicting Moving Objects in View-Shared Time-Resolved 3D MRA

    PubMed Central

    Mostardi, Petrice M.; Haider, Clifton R.; Rossman, Phillip J.; Borisch, Eric A.; Riederer, Stephen J.

    2010-01-01

    Various methods have been used for time-resolved contrast-enhanced MRA (CE-MRA), many involving view sharing. However, the extent to which the resultant image time series represents the actual dynamic behavior of the contrast bolus is not always clear. Although numerical simulations can be used to estimate performance, an experimental study can allow more realistic characterization. The purpose of this work was to use a computer-controlled motion phantom for study of the temporal fidelity of 3D time-resolved sequences in depicting a contrast bolus. It is hypothesized that the view order of the acquisition and the selection of views in the reconstruction can affect the positional accuracy and sharpness of the leading edge of the bolus and artifactual signal preceding the edge. Phantom studies were performed using dilute gadolinium-filled vials that were moved along tabletop tracks by a computer-controlled motor. Several view orders were tested, which use view-sharing and Cartesian sampling. Compactness of measuring the k-space center, consistency of view ordering within each reconstruction frame, and sampling the k-space center near the end of the temporal footprint were shown to be important in accurate portrayal of the leading edge of the bolus. A number of findings were confirmed in an in vivo CE-MRA study. PMID:19319897

  4. Controlled experimental study depicting moving objects in view-shared time-resolved 3D MRA.

    PubMed

    Mostardi, Petrice M; Haider, Clifton R; Rossman, Phillip J; Borisch, Eric A; Riederer, Stephen J

    2009-07-01

    Various methods have been used for time-resolved contrast-enhanced magnetic resonance angiography (CE-MRA), many involving view sharing. However, the extent to which the resultant image time series represents the actual dynamic behavior of the contrast bolus is not always clear. Although numerical simulations can be used to estimate performance, an experimental study can allow more realistic characterization. The purpose of this work was to use a computer-controlled motion phantom for study of the temporal fidelity of three-dimensional (3D) time-resolved sequences in depicting a contrast bolus. It is hypothesized that the view order of the acquisition and the selection of views in the reconstruction can affect the positional accuracy and sharpness of the leading edge of the bolus and artifactual signal preceding the edge. Phantom studies were performed using dilute gadolinium-filled vials that were moved along tabletop tracks by a computer-controlled motor. Several view orders were tested using view-sharing and Cartesian sampling. Compactness of measuring the k-space center, consistency of view ordering within each reconstruction frame, and sampling the k-space center near the end of the temporal footprint were shown to be important in accurate portrayal of the leading edge of the bolus. A number of findings were confirmed in an in vivo CE-MRA study. PMID:19319897

  5. The effects of surface gloss and roughness on color constancy for real 3-D objects.

    PubMed

    Granzier, Jeroen J M; Vergne, Romain; Gegenfurtner, Karl R

    2014-01-01

    Color constancy denotes the phenomenon that the appearance of an object remains fairly stable under changes in illumination and background color. Most of what we know about color constancy comes from experiments using flat, matte surfaces placed on a single plane under diffuse illumination simulated on a computer monitor. Here we investigate whether material properties (glossiness and roughness) have an effect on color constancy for real objects. Subjects matched the color and brightness of cylinders (painted red, green, or blue) illuminated by simulated daylight (D65) or by a reddish light with a Munsell color book illuminated by a tungsten lamp. The cylinders were either glossy or matte and either smooth or rough. The object was placed in front of a black background or a colored checkerboard. We found that color constancy was significantly higher for the glossy objects compared to the matte objects, and higher for the smooth objects compared to the rough objects. This was independent of the background. We conclude that material properties like glossiness and roughness can have significant effects on color constancy. PMID:24563527

  6. Modeling 3-D objects with planar surfaces for prediction of electromagnetic scattering

    NASA Technical Reports Server (NTRS)

    Koch, M. B.; Beck, F. B.; Cockrell, C. R.

    1992-01-01

    Electromagnetic scattering analysis of objects at resonance is difficult because low frequency techniques are slow and computer intensive, and high frequency techniques may not be reliable. A new technique for predicting the electromagnetic backscatter from electrically conducting objects at resonance is studied. This technique is based on modeling three dimensional objects as a combination of flat plates where some of the plates are blocking the scattering from others. A cube is analyzed as a simple example. The preliminary results compare well with the Geometrical Theory of Diffraction and with measured data.

  7. Recovery of 3D volume from 2-tone images of novel objects.

    PubMed

    Moore, C; Cavanagh, P

    1998-07-01

    In 2-tone images (e.g., Dallenbach's cow), only two levels of brightness are used to convey image structure-dark object regions and shadows are turned to black and light regions are light regions are turned white. Despite a lack of shading, hue and texture information, many 2-tone images of familiar objects and scenes are accurately interpreted, even by naive observers. Objects frequently appear fully volumetric and are distinct from their shadows. If perceptual interpretation of 2-tone images is accomplished via bottom-up processes on the basis of geometrical structure projected to the image (e.g., volumetric parts, contour and junction information) novel objects should appear volumetric as readily as their familiar counterparts. We demonstrate that accurate volumetric representations are rarely extracted from 2-tone images of novel objects, even when these objects are constructed from volumetric primitives such as generalized cones (Marr, D., Nishihara, H.K., 1978. Proceedings of the Royal Society London 200, 269-294; Biederman, I. 1985. Computer Vision, Graphics, and Image Processing 32, 29-73), or from the rearranged components of a familiar object which is itself recognizable as a 2-tone image. Even familiar volumes such as canonical bricks and cylinders require scenes with redundant structure (e.g., rows of cylinders) or explicit lighting (a lamp in the image) for recovery of global volumetric shape. We conclude that 2-tone image perception is not mediated by bottom-up extraction of geometrical features such as junctions or volumetric parts, but may rely on previously stored representations in memory and a model of the illumination of the scene. The success of this top-down strategy implies it is available for general object recognition in natural scenes. PMID:9735536

  8. Automatic 3D object recognition and reconstruction based on neuro-fuzzy modelling

    NASA Astrophysics Data System (ADS)

    Samadzadegan, Farhad; Azizi, Ali; Hahn, Michael; Lucas, Curo

    Three-dimensional object recognition and reconstruction (ORR) is a research area of major interest in computer vision and photogrammetry. Virtual cities, for example, is one of the exciting application fields of ORR which became very popular during the last decade. Natural and man-made objects of cities such as trees and buildings are complex structures and automatic recognition and reconstruction of these objects from digital aerial images but also other data sources is a big challenge. In this paper a novel approach for object recognition is presented based on neuro-fuzzy modelling. Structural, textural and spectral information is extracted and integrated in a fuzzy reasoning process. The learning capability of neural networks is introduced to the fuzzy recognition process by taking adaptable parameter sets into account which leads to the neuro-fuzzy approach. Object reconstruction follows recognition seamlessly by using the recognition output and the descriptors which have been extracted for recognition. A first successful application of this new ORR approach is demonstrated for the three object classes 'buildings', 'cars' and 'trees' by using aerial colour images of an urban area of the town of Engen in Germany.

  9. Robust 3D object localization and pose estimation for random bin picking with the 3DMaMa algorithm

    NASA Astrophysics Data System (ADS)

    Skotheim, Øystein; Thielemann, Jens T.; Berge, Asbjørn; Sommerfelt, Arne

    2010-02-01

    Enabling robots to automatically locate and pick up randomly placed and oriented objects from a bin is an important challenge in factory automation, replacing tedious and heavy manual labor. A system should be able to recognize and locate objects with a predefined shape and estimate the position with the precision necessary for a gripping robot to pick it up. We describe a system that consists of a structured light instrument for capturing 3D data and a robust approach for object location and pose estimation. The method does not depend on segmentation of range images, but instead searches through pairs of 2D manifolds to localize candidates for object match. This leads to an algorithm that is not very sensitive to scene complexity or the number of objects in the scene. Furthermore, the strategy for candidate search is easily reconfigurable to arbitrary objects. Experiments reported in this paper show the utility of the method on a general random bin picking problem, in this paper exemplified by localization of car parts with random position and orientation. Full pose estimation is done in less than 380 ms per image. We believe that the method is applicable for a wide range of industrial automation problems where precise localization of 3D objects in a scene is needed.

  10. Recognition of 3-D symmetric objects from range images in automated assembly tasks

    NASA Technical Reports Server (NTRS)

    Alvertos, Nicolas; Dcunha, Ivan

    1990-01-01

    A new technique is presented for the three dimensional recognition of symmetric objects from range images. Beginning from the implicit representation of quadrics, a set of ten coefficients is determined for symmetric objects like spheres, cones, cylinders, ellipsoids, and parallelepipeds. Instead of using these ten coefficients trying to fit them to smooth surfaces (patches) based on the traditional way of determining curvatures, a new approach based on two dimensional geometry is used. For each symmetric object, a unique set of two dimensional curves is obtained from the various angles at which the object is intersected with a plane. Using the same ten coefficients obtained earlier and based on the discriminant method, each of these curves is classified as a parabola, circle, ellipse, or hyperbola. Each symmetric object is found to possess a unique set of these two dimensional curves whereby it can be differentiated from the others. It is shown that instead of using the three dimensional discriminant which involves evaluation of the rank of its matrix, it is sufficient to use the two dimensional discriminant which only requires three arithmetic operations.

  11. Detection of hidden objects using a real-time 3-D millimeter-wave imaging system

    NASA Astrophysics Data System (ADS)

    Rozban, Daniel; Aharon, Avihai; Levanon, Assaf; Abramovich, Amir; Yitzhaky, Yitzhak; Kopeika, N. S.

    2014-10-01

    Millimeter (mm)and sub-mm wavelengths or terahertz (THz) band have several properties that motivate their use in imaging for security applications such as recognition of hidden objects, dangerous materials, aerosols, imaging through walls as in hostage situations, and also in bad weather conditions. There is no known ionization hazard for biological tissue, and atmospheric degradation of THz radiation is relatively low for practical imaging distances. We recently developed a new technology for the detection of THz radiation. This technology is based on very inexpensive plasma neon indicator lamps, also known as Glow Discharge Detector (GDD), that can be used as very sensitive THz radiation detectors. Using them, we designed and constructed a Focal Plane Array (FPA) and obtained recognizable2-dimensional THz images of both dielectric and metallic objects. Using THz wave it is shown here that even concealed weapons made of dielectric material can be detected. An example is an image of a knife concealed inside a leather bag and also under heavy clothing. Three-dimensional imaging using radar methods can enhance those images since it can allow the isolation of the concealed objects from the body and environmental clutter such as nearby furniture or other people. The GDDs enable direct heterodyning between the electric field of the target signal and the reference signal eliminating the requirement for expensive mixers, sources, and Low Noise Amplifiers (LNAs).We expanded the ability of the FPA so that we are able to obtain recognizable 2-dimensional THz images in real time. We show here that the THz detection of objects in three dimensions, using FMCW principles is also applicable in real time. This imaging system is also shown here to be capable of imaging objects from distances allowing standoff detection of suspicious objects and humans from large distances.

  12. Microwave and camera sensor fusion for the shape extraction of metallic 3D space objects

    NASA Technical Reports Server (NTRS)

    Shaw, Scott W.; Defigueiredo, Rui J. P.; Krishen, Kumar

    1989-01-01

    The vacuum of space presents special problems for optical image sensors. Metallic objects in this environment can produce intense specular reflections and deep shadows. By combining the polarized RCS with an incomplete camera image, it has become possible to better determine the shape of some simple three-dimensional objects. The radar data are used in an iterative procedure that generates successive approximations to the target shape by minimizing the error between computed scattering cross-sections and the observed radar returns. Favorable results have been obtained for simulations and experiments reconstructing plates, ellipsoids, and arbitrary surfaces.

  13. Visual retrieval of known objects using supplementary depth data

    NASA Astrophysics Data System (ADS)

    Śluzek, Andrzej

    2016-06-01

    A simple modification of typical content-based visual information retrieval (CBVIR) techniques (e.g. MSER keypoints represented by SIFT descriptors quantized into sufficiently large vocabularies) is discussed and preliminarily evaluated. By using the approximate depths (as the supplementary data) of the detected keypoints, we can significantly improve credibility of keypoint matching so that known objects (i.e. objects for which exemplary images are available in the database) can be detected at low computational costs. Thus, the method can be particularly useful in real-time applications of machine vision systems (e.g. in intelligent robotic devices). The paper presents theoretical model of the method and provides exemplary results for selected scenarios.

  14. Data amalgamation in the digitalization of 3D objects all over its 360 degrees

    NASA Astrophysics Data System (ADS)

    Rayas, Juan A.; Rodriguez-Vera, Ramon; Martinez, Amalia

    2005-02-01

    It is described a technique where different views of an object are connected to recover its three-dimensional form in a field of vision of 360°. The object is placed on a rotary motorized platform and projected a linear fringe pattern. In each angular object displacement, the projected fringe pattern is captured by a camera CCD. Each pattern is digitally demodulated providing information of depth. The format of the digital matrix, this is, the image type, is changed for one of triads (x, y, z). This way, a cloud of independent points of their position in the matrix is constructed. As a reference, one point in each cloud (known it a priori), is taken. All the clouds are rotated and displaced until the reference point taking its corresponding position. Different mixed clouds of points (views) are ordered in a single triad matrix that describes the complete surface of the object surface target. Finally a mesh of quadrilaterals is built up that makes possible to generate a solid surface.

  15. 3D Cloud Radiative Effects on Aerosol Optical Thickness Retrievals in Cumulus Cloud Fields in the Biomass Burning Region in Brazil

    NASA Technical Reports Server (NTRS)

    Wen, Guo-Yong; Marshak, Alexander; Cahalan, Robert F.

    2004-01-01

    Aerosol amount in clear regions of a cloudy atmosphere is a critical parameter in studying the interaction between aerosols and clouds. Since the global cloud cover is about 50%, cloudy scenes are often encountered in any satellite images. Aerosols are more or less transparent, while clouds are extremely reflective in the visible spectrum of solar radiation. The radiative transfer in clear-cloudy condition is highly three- dimensional (3D). This paper focuses on estimating the 3D effects on aerosol optical thickness retrievals using Monte Carlo simulations. An ASTER image of cumulus cloud fields in the biomass burning region in Brazil is simulated in this study. The MODIS products (i-e., cloud optical thickness, particle effective radius, cloud top pressure, surface reflectance, etc.) are used to construct the cloud property and surface reflectance fields. To estimate the cloud 3-D effects, we assume a plane-parallel stratification of aerosol properties in the 60 km x 60 km ASTER image. The simulated solar radiation at the top of the atmosphere is compared with plane-parallel calculations. Furthermore, the 3D cloud radiative effects on aerosol optical thickness retrieval are estimated.

  16. A roadmap to global illumination in 3D scenes: solutions for GPU object recognition applications

    NASA Astrophysics Data System (ADS)

    Picos, Kenia; Díaz-Ramírez, Victor H.; Tapia, Juan J.

    2014-09-01

    Light interactions with matter is of remarkable complexity. An adequate modeling of global illumination is a vastly studied topic since the beginning of computer graphics, and still is an unsolved problem. The rendering equation for global illumination is based of refraction and reflection of light in interaction with matter within an environment. This physical process possesses a high computational complexity when implemented in a digital computer. The appearance of an object depends on light interactions with the surface of the material, such as emission, scattering, and absorption. Several image-synthesis methods have been used to realistically render the appearance of light incidence on an object. Recent global illumination algorithms employ mathematical models and computational strategies that improve the efficiency of the simulation solution. This work presents a review the state of the art of global illumination algorithms and focuses on the efficiency of the solution in a computational implementation in a graphics processing unit. A reliable system is developed to simulate realistics scenes in the context of real-time object recognition under different lighting conditions. Computer simulations results are presented and discussed in terms of discrimination capability, and robustness to additive noise, when considering several lighting model reflections and multiple light sources.

  17. Calibration and 3D reconstruction of underwater objects with non-single-view projection model by structured light stereo imaging.

    PubMed

    Wang, Yexin; Negahdaripour, Shahriar; Aykin, Murat D

    2016-08-20

    Establishing the projection model of imaging systems is critical in 3D reconstruction of object shapes from multiple 2D views. When deployed underwater, these are enclosed in waterproof housings with transparent glass ports that generate nonlinear refractions of optical rays at interfaces, leading to invalidation of the commonly assumed single-viewpoint (SVP) model. In this paper, we propose a non-SVP ray tracing model for the calibration of a projector-camera system, employed for 3D reconstruction based on the structured light paradigm. The projector utilizes dot patterns, having established that the contrast loss is less severe than for traditional stripe patterns in highly turbid waters. Experimental results are presented to assess the achieved calibrating accuracy. PMID:27556973

  18. In-hand dexterous manipulation of piecewise-smooth 3-D objects

    SciTech Connect

    Rus, D.

    1999-04-01

    The author presents an algorithm called finger tracking for in-hand manipulation of three-dimensional objects with independent robot fingers. She describes and analyzes the differential control for finger tracking and extends it to on-line continuous control for a set of cooperating robot fingers. She shows experimental data from a simulation. Finally, she discusses global control issues for finger tracking, and computes lower bounds for reorientation by finger tracking. The algorithm is computationally efficient, exact, and takes into consideration the full dynamics of the system.

  19. Calculations of Arctic ozone chemistry using objectively analyzed data in a 3-D CTM

    NASA Technical Reports Server (NTRS)

    Kaminski, J. W.; Mcconnell, J. C.; Sandilands, J. W.

    1994-01-01

    A three-dimensional chemical transport model (CTM) (Kaminski, 1992) has been used to study the evolution of the Arctic ozone during the winter of 1992. The continuity equation has been solved using a spectral method with Rhomboidal 15 (R15) truncation and leap-frog time stepping. Six-hourly meteorological fields from the Canadian Meteorological Center global objective analysis routines run at T79 were degraded to the model resolution. In addition, they were interpolated to the model time grid and were used to drive the model from the surface to 10 mb. In the model, processing of Cl(x) occurred over Arctic latitudes but some of the initial products were still present by mid-January. Also, the large amounts of ClO formed in the model in early January were converted to ClNO3. The results suggest that the model resolution may be insufficient to resolve the details of the Arctic transport during this time period. In particular, the wind field does not move the ClO(x) 'cloud' to the south over Europe as seen in the MLS measurements.

  20. A supervised method for object-based 3D building change detection on aerial stereo images

    NASA Astrophysics Data System (ADS)

    Qin, R.; Gruen, A.

    2014-08-01

    There is a great demand for studying the changes of buildings over time. The current trend for building change detection combines the orthophoto and DSM (Digital Surface Models). The pixel-based change detection methods are very sensitive to the quality of the images and DSMs, while the object-based methods are more robust towards these problems. In this paper, we propose a supervised method for building change detection. After a segment-based SVM (Support Vector Machine) classification with features extracted from the orthophoto and DSM, we focus on the detection of the building changes of different periods by measuring their height and texture differences, as well as their shapes. A decision tree analysis is used to assess the probability of change for each building segment and the traffic lighting system is used to indicate the status "change", "non-change" and "uncertain change" for building segments. The proposed method is applied to scanned aerial photos of the city of Zurich in 2002 and 2007, and the results have demonstrated that our method is able to achieve high detection accuracy.

  1. Reference Frames and 3-D Shape Perception of Pictured Objects: On Verticality and Viewpoint-From-Above

    PubMed Central

    van Doorn, Andrea J.; Wagemans, Johan

    2016-01-01

    Research on the influence of reference frames has generally focused on visual phenomena such as the oblique effect, the subjective visual vertical, the perceptual upright, and ambiguous figures. Another line of research concerns mental rotation studies in which participants had to discriminate between familiar or previously seen 2-D figures or pictures of 3-D objects and their rotated versions. In the present study, we disentangled the influence of the environmental and the viewer-centered reference frame, as classically done, by comparing the performances obtained in various picture and participant orientations. However, this time, the performance is the pictorial relief: the probed 3-D shape percept of the depicted object reconstructed from the local attitude settings of the participant. Comparisons between the pictorial reliefs based on different picture and participant orientations led to two major findings. First, in general, the pictorial reliefs were highly similar if the orientation of the depicted object was vertical with regard to the environmental or the viewer-centered reference frame. Second, a viewpoint-from-above interpretation could almost completely account for the shears occurring between the pictorial reliefs. More specifically, the shears could largely be considered as combinations of slants generated from the viewpoint-from-above, which was determined by the environmental as well as by the viewer-centered reference frame. PMID:27433329

  2. An effective 3D leapfrog scheme for electromagnetic modelling of arbitrary shaped dielectric objects using unstructured meshes

    NASA Astrophysics Data System (ADS)

    Gansen, A.; El Hachemi, M.; Belouettar, S.; Hassan, O.; Morgan, K.

    2015-12-01

    In computational electromagnetics, the advantages of the standard Yee algorithm are its simplicity and its low computational costs. However, because of the accuracy losses resulting from the staircased representation of curved interfaces, it is normally not the method of choice for modelling electromagnetic interactions with objects of arbitrary shape. For these problems, an unstructured mesh finite volume time domain method is often employed, although the scheme does not satisfy the divergence free condition at the discrete level. In this paper, we generalize the standard Yee algorithm for use on unstructured meshes and solve the problem concerning the loss of accuracy linked to staircasing, while preserving the divergence free nature of the algorithm. The scheme is implemented on high quality primal Delaunay and dual Voronoi meshes. The performance of the approach was validated in previous work by simulating the scattering of electromagnetic waves by spherical 3D PEC objects in free space. In this paper we demonstrate the performance of this scheme for penetration problems in lossy dielectrics using a new averaging technique for Delaunay and Voronoi edges at the interface. A detailed explanation of the implementation of the method, and a demonstration of the quality of the results obtained for transmittance and scattering simulations by 3D objects of arbitrary shapes, are presented.

  3. Spun-wrapped aligned nanofiber (SWAN) lithography for fabrication of micro/nano-structures on 3D objects.

    PubMed

    Ye, Zhou; Nain, Amrinder S; Behkam, Bahareh

    2016-07-01

    Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10(-7) m(2) s(-1)) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b(1.5)∝D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features. PMID:27283144

  4. Parallel phase-shifting digital holography and its application to high-speed 3D imaging of dynamic object

    NASA Astrophysics Data System (ADS)

    Awatsuji, Yasuhiro; Xia, Peng; Wang, Yexin; Matoba, Osamu

    2016-03-01

    Digital holography is a technique of 3D measurement of object. The technique uses an image sensor to record the interference fringe image containing the complex amplitude of object, and numerically reconstructs the complex amplitude by computer. Parallel phase-shifting digital holography is capable of accurate 3D measurement of dynamic object. This is because this technique can reconstruct the complex amplitude of object, on which the undesired images are not superimposed, form a single hologram. The undesired images are the non-diffraction wave and the conjugate image which are associated with holography. In parallel phase-shifting digital holography, a hologram, whose phase of the reference wave is spatially and periodically shifted every other pixel, is recorded to obtain complex amplitude of object by single-shot exposure. The recorded hologram is decomposed into multiple holograms required for phase-shifting digital holography. The complex amplitude of the object is free from the undesired images is reconstructed from the multiple holograms. To validate parallel phase-shifting digital holography, a high-speed parallel phase-shifting digital holography system was constructed. The system consists of a Mach-Zehnder interferometer, a continuous-wave laser, and a high-speed polarization imaging camera. Phase motion picture of dynamic air flow sprayed from a nozzle was recorded at 180,000 frames per second (FPS) have been recorded by the system. Also phase motion picture of dynamic air induced by discharge between two electrodes has been recorded at 1,000,000 FPS, when high voltage was applied between the electrodes.

  5. Retrieving 3D Velocity Fields of Glaciers from X-band SAR Data and Comparison with GPS Observations

    NASA Astrophysics Data System (ADS)

    Magnússon, E.; Nagler, T.; Hetzenecker, M.; Palsson, F.; Scharrer, K.; Floricioiu, D.; Berthier, E.; Gudmundsson, S.; Rott, H.

    2013-12-01

    We present 3D velocity fields obtained from time series of TerraSAR-X and TanDEM-X images acquired over the ablation area of the Breidamerkurjökull outlet glacier of Vatnjökull Ice Cap (Iceland) in 2008-2012. Coherent and incoherent offset tracking is applied to repeat pass X-Band data to obtain ice displacement in cross and along track direction. Three methods are tested and compared to extract fields of the 3D ice velocity. First, the conventional surface parallel approach, which we consider as an approximation for deriving the horizontal motion rate, but does not reveal a realistic vertical motion. Second, the combination of offset tracking results from almost simultaneous observations from ascending and descending orbits measuring the glacier motion in four different directions, allowing calculation of the 3D velocity fields without any additional approximations. Third, deriving full 3D velocity fields by using the horizontal flow direction, derived from the ascending-descending combination, as constrain on offset tracking results from a single pair of SAR images. The latter two methods reveal a measurement of the vertical ice motion plus ablation, hence equivalent to the vertical motion component measured by GPS station fixed on a platform laying on the ice surface. The results from all methods are compared with such GPS measurements recorded by permanent stations on the glacier in 2008-2012 and the errors of the different methods are calculated. Additionally, we approximate the contribution of these 3D flow fields to elevation changes (emergence/submergence velocity plus net balance) and compare it with elevation changes from surface DEMs obtained in 2008 (SPIRIT), 2010 (airborne LIDAR) and 2012 (TanDEM-X).

  6. Workflows and the Role of Images for Virtual 3d Reconstruction of no Longer Extant Historic Objects

    NASA Astrophysics Data System (ADS)

    Münster, S.

    2013-07-01

    3D reconstruction technologies have gained importance as tools for the research and visualization of no longer extant historic objects during the last decade. Within such reconstruction processes, visual media assumes several important roles: as the most important sources especially for a reconstruction of no longer extant objects, as a tool for communication and cooperation within the production process, as well as for a communication and visualization of results. While there are many discourses about theoretical issues of depiction as sources and as visualization outcomes of such projects, there is no systematic research about the importance of depiction during a 3D reconstruction process and based on empirical findings. Moreover, from a methodological perspective, it would be necessary to understand which role visual media plays during the production process and how it is affected by disciplinary boundaries and challenges specific to historic topics. Research includes an analysis of published work and case studies investigating reconstruction projects. This study uses methods taken from social sciences to gain a grounded view of how production processes would take place in practice and which functions and roles images would play within them. For the investigation of these topics, a content analysis of 452 conference proceedings and journal articles related to 3D reconstruction modeling in the field of humanities has been completed. Most of the projects described in those publications dealt with data acquisition and model building for existing objects. Only a small number of projects focused on structures that no longer or never existed physically. Especially that type of project seems to be interesting for a study of the importance of pictures as sources and as tools for interdisciplinary cooperation during the production process. In the course of the examination the authors of this paper applied a qualitative content analysis for a sample of 26 previously

  7. Multi-frequency color-marked fringe projection profilometry for fast 3D shape measurement of complex objects.

    PubMed

    Jiang, Chao; Jia, Shuhai; Dong, Jun; Bao, Qingchen; Yang, Jia; Lian, Qin; Li, Dichen

    2015-09-21

    We propose a novel multi-frequency color-marked fringe projection profilometry approach to measure the 3D shape of objects with depth discontinuities. A digital micromirror device projector is used to project a color map consisting of a series of different-frequency color-marked fringe patterns onto the target object. We use a chromaticity curve to calculate the color change caused by the height of the object. The related algorithm to measure the height is also described in this paper. To improve the measurement accuracy, a chromaticity curve correction method is presented. This correction method greatly reduces the influence of color fluctuations and measurement error on the chromaticity curve and the calculation of the object height. The simulation and experimental results validate the utility of our method. Our method avoids the conventional phase shifting and unwrapping process, as well as the independent calculation of the object height required by existing techniques. Thus, it can be used to measure complex and dynamic objects with depth discontinuities. These advantages are particularly promising for industrial applications. PMID:26406621

  8. Colorful holographic display of 3D object based on scaled diffraction by using non-uniform fast Fourier transform

    NASA Astrophysics Data System (ADS)

    Chang, Chenliang; Xia, Jun; Lei, Wei

    2015-03-01

    We proposed a new method to calculate the color computer generated hologram of three-dimensional object in holographic display. The three-dimensional object is composed of several tilted planes which are tilted from the hologram. The diffraction from each tilted plane to the hologram plane is calculated based on the coordinate rotation in Fourier spectrum domains. We used the nonuniform fast Fourier transformation (NUFFT) to calculate the nonuniform sampled Fourier spectrum on the tilted plane after coordinate rotation. By using the NUFFT, the diffraction calculation from tilted plane to the hologram plane with variable sampling rates can be achieved, which overcomes the sampling restriction of FFT in the conventional angular spectrum based method. The holograms of red, green and blue component of the polygon-based object are calculated separately by using our NUFFT based method. Then the color hologram is synthesized by placing the red, green and blue component hologram in sequence. The chromatic aberration caused by the wavelength difference can be solved effectively by restricting the sampling rate of the object in the calculation of each wavelength component. The computer simulation shows the feasibility of our method in calculating the color hologram of polygon-based object. The 3D object can be displayed in color with adjustable size and no chromatic aberration in holographic display system, which can be considered as an important application in the colorful holographic three-dimensional display.

  9. If you watch it move, you'll recognize it in 3D: Transfer of depth cues between encoding and retrieval.

    PubMed

    Papenmeier, Frank; Schwan, Stephan

    2016-02-01

    Viewing objects with stereoscopic displays provides additional depth cues through binocular disparity supporting object recognition. So far, it was unknown whether this results from the representation of specific stereoscopic information in memory or a more general representation of an object's depth structure. Therefore, we investigated whether continuous object rotation acting as depth cue during encoding results in a memory representation that can subsequently be accessed by stereoscopic information during retrieval. In Experiment 1, we found such transfer effects from continuous object rotation during encoding to stereoscopic presentations during retrieval. In Experiments 2a and 2b, we found that the continuity of object rotation is important because only continuous rotation and/or stereoscopic depth but not multiple static snapshots presented without stereoscopic information caused the extraction of an object's depth structure into memory. We conclude that an object's depth structure and not specific depth cues are represented in memory. PMID:26765253

  10. 3D Visual Data-Driven Spatiotemporal Deformations for Non-Rigid Object Grasping Using Robot Hands.

    PubMed

    Mateo, Carlos M; Gil, Pablo; Torres, Fernando

    2016-01-01

    Sensing techniques are important for solving problems of uncertainty inherent to intelligent grasping tasks. The main goal here is to present a visual sensing system based on range imaging technology for robot manipulation of non-rigid objects. Our proposal provides a suitable visual perception system of complex grasping tasks to support a robot controller when other sensor systems, such as tactile and force, are not able to obtain useful data relevant to the grasping manipulation task. In particular, a new visual approach based on RGBD data was implemented to help a robot controller carry out intelligent manipulation tasks with flexible objects. The proposed method supervises the interaction between the grasped object and the robot hand in order to avoid poor contact between the fingertips and an object when there is neither force nor pressure data. This new approach is also used to measure changes to the shape of an object's surfaces and so allows us to find deformations caused by inappropriate pressure being applied by the hand's fingers. Test was carried out for grasping tasks involving several flexible household objects with a multi-fingered robot hand working in real time. Our approach generates pulses from the deformation detection method and sends an event message to the robot controller when surface deformation is detected. In comparison with other methods, the obtained results reveal that our visual pipeline does not use deformations models of objects and materials, as well as the approach works well both planar and 3D household objects in real time. In addition, our method does not depend on the pose of the robot hand because the location of the reference system is computed from a recognition process of a pattern located place at the robot forearm. The presented experiments demonstrate that the proposed method accomplishes a good monitoring of grasping task with several objects and different grasping configurations in indoor environments. PMID:27164102

  11. Spun-wrapped aligned nanofiber (SWAN) lithography for fabrication of micro/nano-structures on 3D objects

    NASA Astrophysics Data System (ADS)

    Ye, Zhou; Nain, Amrinder S.; Behkam, Bahareh

    2016-06-01

    Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10-7 m2 s-1) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b1.5 ~ D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features.Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for

  12. 3D Visual Data-Driven Spatiotemporal Deformations for Non-Rigid Object Grasping Using Robot Hands

    PubMed Central

    Mateo, Carlos M.; Gil, Pablo; Torres, Fernando

    2016-01-01

    Sensing techniques are important for solving problems of uncertainty inherent to intelligent grasping tasks. The main goal here is to present a visual sensing system based on range imaging technology for robot manipulation of non-rigid objects. Our proposal provides a suitable visual perception system of complex grasping tasks to support a robot controller when other sensor systems, such as tactile and force, are not able to obtain useful data relevant to the grasping manipulation task. In particular, a new visual approach based on RGBD data was implemented to help a robot controller carry out intelligent manipulation tasks with flexible objects. The proposed method supervises the interaction between the grasped object and the robot hand in order to avoid poor contact between the fingertips and an object when there is neither force nor pressure data. This new approach is also used to measure changes to the shape of an object’s surfaces and so allows us to find deformations caused by inappropriate pressure being applied by the hand’s fingers. Test was carried out for grasping tasks involving several flexible household objects with a multi-fingered robot hand working in real time. Our approach generates pulses from the deformation detection method and sends an event message to the robot controller when surface deformation is detected. In comparison with other methods, the obtained results reveal that our visual pipeline does not use deformations models of objects and materials, as well as the approach works well both planar and 3D household objects in real time. In addition, our method does not depend on the pose of the robot hand because the location of the reference system is computed from a recognition process of a pattern located place at the robot forearm. The presented experiments demonstrate that the proposed method accomplishes a good monitoring of grasping task with several objects and different grasping configurations in indoor environments. PMID

  13. Single objective light-sheet microscopy for high-speed whole-cell 3D super-resolution

    PubMed Central

    Meddens, Marjolein B. M.; Liu, Sheng; Finnegan, Patrick S.; Edwards, Thayne L.; James, Conrad D.; Lidke, Keith A.

    2016-01-01

    We have developed a method for performing light-sheet microscopy with a single high numerical aperture lens by integrating reflective side walls into a microfluidic chip. These 45° side walls generate light-sheet illumination by reflecting a vertical light-sheet into the focal plane of the objective. Light-sheet illumination of cells loaded in the channels increases image quality in diffraction limited imaging via reduction of out-of-focus background light. Single molecule super-resolution is also improved by the decreased background resulting in better localization precision and decreased photo-bleaching, leading to more accepted localizations overall and higher quality images. Moreover, 2D and 3D single molecule super-resolution data can be acquired faster by taking advantage of the increased illumination intensities as compared to wide field, in the focused light-sheet. PMID:27375939

  14. Single objective light-sheet microscopy for high-speed whole-cell 3D super-resolution

    DOE PAGESBeta

    Meddens, Marjolein B. M.; Liu, Sheng; Finnegan, Patrick S.; Edwards, Thayne L.; James, Conrad D.; Lidke, Keith A.

    2016-05-01

    Here, we have developed a method for performing light-sheet microscopy with a single high numerical aperture lens by integrating reflective side walls into a microfluidic chip. These 45° side walls generate light-sheet illumination by reflecting a vertical light-sheet into the focal plane of the objective. Light-sheet illumination of cells loaded in the channels increases image quality in diffraction limited imaging via reduction of out-of-focus background light. Single molecule super-resolution is also improved by the decreased background resulting in better localization precision and decreased photo-bleaching, leading to more accepted localizations overall and higher quality images. Moreover, 2D and 3D single moleculemore » super-resolution data can be acquired faster by taking advantage of the increased illumination intensities as compared to wide field, in the focused light-sheet.« less

  15. Single objective light-sheet microscopy for high-speed whole-cell 3D super-resolution.

    PubMed

    Meddens, Marjolein B M; Liu, Sheng; Finnegan, Patrick S; Edwards, Thayne L; James, Conrad D; Lidke, Keith A

    2016-06-01

    We have developed a method for performing light-sheet microscopy with a single high numerical aperture lens by integrating reflective side walls into a microfluidic chip. These 45° side walls generate light-sheet illumination by reflecting a vertical light-sheet into the focal plane of the objective. Light-sheet illumination of cells loaded in the channels increases image quality in diffraction limited imaging via reduction of out-of-focus background light. Single molecule super-resolution is also improved by the decreased background resulting in better localization precision and decreased photo-bleaching, leading to more accepted localizations overall and higher quality images. Moreover, 2D and 3D single molecule super-resolution data can be acquired faster by taking advantage of the increased illumination intensities as compared to wide field, in the focused light-sheet. PMID:27375939

  16. Single objective light-sheet microscopy for high-speed whole-cell 3D super-resolution

    SciTech Connect

    Meddens, Marjolein B. M.; Liu, Sheng; Finnegan, Patrick S.; Edwards, Thayne L.; James, Conrad D.; Lidke, Keith A.

    2016-01-01

    Here, we have developed a method for performing light-sheet microscopy with a single high numerical aperture lens by integrating reflective side walls into a microfluidic chip. These 45° side walls generate light-sheet illumination by reflecting a vertical light-sheet into the focal plane of the objective. Light-sheet illumination of cells loaded in the channels increases image quality in diffraction limited imaging via reduction of out-of-focus background light. Single molecule super-resolution is also improved by the decreased background resulting in better localization precision and decreased photo-bleaching, leading to more accepted localizations overall and higher quality images. Moreover, 2D and 3D single molecule super-resolution data can be acquired faster by taking advantage of the increased illumination intensities as compared to wide field, in the focused light-sheet.

  17. Retrieval of Shape Characteristics for Buried Objects with GPR Monitoring

    NASA Astrophysics Data System (ADS)

    Soldovieri, F.; Comite, D.; Galli, A.; Valerio, G.; Barone, P. M.; Lauro, S. E.; Mattei, E.; Pettinelli, E.

    2012-04-01

    Information retrieval on the location and the geometrical features (dimensions and shape) of buried objects is of fundamental importance in geosciences areas involving environmental protection, mine clearance, archaeological investigations, space and planetary exploration, and so forth. Among the different non-invasive sensing techniques usually employed to achieve this kind of information, those based on ground-penetrating-radar (GPR) instruments are well-established and suitable to the mentioned purposes [1]. In this context, our interest in the present work is specifically focused on testing the potential performance of typical GPR instruments by means of appropriate data processing. It will be shown in particular to what extent the use of a suitable "microwave tomographic approach" [2] is able to furnish a shape estimation of the targets, possibly recognizing different kinds of canonical geometries, even having reduced cross sections and in critical conditions, where the scatterer size is comparable with resolution limits imposed by the usual measurement configurations. Our study starts by obtaining the typical "direct" information from the GPR techniques that is the scattered field in subsurface environments under the form of radargrams. In order to get a wide variety of scenarios for the operating conditions, this goal is achieved by means of two different and independent approaches [3]. One approach is based on direct measurements through an experimental laboratory setup: commercial GPR instruments (typically bistatic configurations operating around 1 GHz frequency range) are used to collect radargram profiles by investigating an artificial basin filled of liquid and/or granular materials (sand, etc.), in which targets (having different constitutive parameters, shape, and dimensions) can be buried. The other approach is based on numerical GPR simulations by means of a commercial CAD electromagnetic tool (CST), whose suitable implementation and data

  18. 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.

  19. Rapid and retrievable recording of big data of time-lapse 3D shadow images of microbial colonies.

    PubMed

    Ogawa, Hiroyuki; Nasu, Senshi; Takeshige, Motomu; Saito, Mikako; Matsuoka, Hideaki

    2015-01-01

    We formerly developed an automatic colony count system based on the time-lapse shadow image analysis (TSIA). Here this system has been upgraded and applied to practical rapid decision. A microbial sample was spread on/in an agar plate with 90 mm in diameter as homogeneously as possible. We could obtain the results with several strains that most of colonies appeared within a limited time span. Consequently the number of colonies reached a steady level (Nstdy) and then unchanged until the end of long culture time to give the confirmed value (Nconf). The equivalence of Nstdy and Nconf as well as the difference of times for Nstdy and Nconf determinations were statistically significant at p < 0.001. Nstdy meets the requirement of practical routines treating a large number of plates. The difference of Nstdy and Nconf, if any, may be elucidated by means of retrievable big data. Therefore Nconf is valid for official documentation. PMID:25975590

  20. 3D Imaging.

    ERIC Educational Resources Information Center

    Hastings, S. K.

    2002-01-01

    Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

  1. 3D shape and eccentricity measurements of fast rotating rough objects by two mutually tilted interference fringe systems

    NASA Astrophysics Data System (ADS)

    Czarske, J. W.; Kuschmierz, R.; Günther, P.

    2013-06-01

    Precise measurements of distance, eccentricity and 3D-shape of fast moving objects such as turning parts of lathes, gear shafts, magnetic bearings, camshafts, crankshafts and rotors of vacuum pumps are on the one hand important tasks. On the other hand they are big challenges, since contactless precise measurement techniques are required. Optical techniques are well suitable for distance measurements of non-moving surfaces. However, measurements of laterally fast moving surfaces are still challenging. For such tasks the laser Doppler distance sensor technique was invented by the TU Dresden some years ago. This technique has been realized by two mutually tilted interference fringe systems, where the distance is coded in the phase difference between the generated interference signals. However, due to the speckle effect different random envelopes and phase jumps of the interference signals occur. They disturb the phase difference estimation between the interference signals. In this paper, we will report on a scientific breakthrough on the measurement uncertainty budget which has been achieved recently. Via matching of the illumination and receiving optics the measurement uncertainty of the displacement and distance can be reduced by about one magnitude. For displacement measurements of a recurring rough surface a standard deviation of 110 nm were attained at lateral velocities of 5 m / s. Due to the additionally measured lateral velocity and the rotational speed, the two-dimensional shape of rotating objects is calculated. The three-dimensional shape can be conducted by employment of a line camera. Since the measurement uncertainty of the displacement, vibration, distance, eccentricity, and shape is nearly independent of the lateral surface velocity, this technique is predestined for fast-rotating objects. Especially it can be advantageously used for the quality control of workpieces inside of a lathe towards the reduction of process tolerances, installation times and

  2. Object-constrained meshless deformable algorithm for high speed 3D nonrigid registration between CT and CBCT

    SciTech Connect

    Chen Ting; Kim, Sung; Goyal, Sharad; Jabbour, Salma; Zhou Jinghao; Rajagopal, Gunaretnum; Haffty, Bruce; Yue Ning

    2010-01-15

    Purpose: High-speed nonrigid registration between the planning CT and the treatment CBCT data is critical for real time image guided radiotherapy (IGRT) to improve the dose distribution and to reduce the toxicity to adjacent organs. The authors propose a new fully automatic 3D registration framework that integrates object-based global and seed constraints with the grayscale-based ''demons'' algorithm. Methods: Clinical objects were segmented on the planning CT images and were utilized as meshless deformable models during the nonrigid registration process. The meshless models reinforced a global constraint in addition to the grayscale difference between CT and CBCT in order to maintain the shape and the volume of geometrically complex 3D objects during the registration. To expedite the registration process, the framework was stratified into hierarchies, and the authors used a frequency domain formulation to diffuse the displacement between the reference and the target in each hierarchy. Also during the registration of pelvis images, they replaced the air region inside the rectum with estimated pixel values from the surrounding rectal wall and introduced an additional seed constraint to robustly track and match the seeds implanted into the prostate. The proposed registration framework and algorithm were evaluated on 15 real prostate cancer patients. For each patient, prostate gland, seminal vesicle, bladder, and rectum were first segmented by a radiation oncologist on planning CT images for radiotherapy planning purpose. The same radiation oncologist also manually delineated the tumor volumes and critical anatomical structures in the corresponding CBCT images acquired at treatment. These delineated structures on the CBCT were only used as the ground truth for the quantitative validation, while structures on the planning CT were used both as the input to the registration method and the ground truth in validation. By registering the planning CT to the CBCT, a

  3. 3D Monte Carlo simulation of solar radiance in the clear-sky and low-cloud atmosphere for retrieval of aerosol and cloud characteristics

    NASA Astrophysics Data System (ADS)

    Zhuravleva, Tatiana; Bedareva, Tatiana; Nasrtdinov, Ilmir

    As is well known, the spectral measurements of direct and diffuse solar radiation can be used to retrieve the optical and microphysical characteristics of atmospheric aerosol and clouds. Most methods of radiation calculations, which are used to solve the inverse problems, are implemented under the assumption of horizontal homogeneity of the atmosphere (clear-sky and overcast conditions). However, it is recognized that the 3D effects of clouds have a significant impact on the transfer of solar radiation in the atmosphere which can be the cause of errors in retrieval of aerosol and cloud properties. In this work, we present the algorithms of the Monte Carlo method for calculating the angular structure of diffuse radiation in the molecular-aerosol atmosphere and the appearance of isolated cloud. The simulation of radiative characteristics with specified spectral resolution is performed in spherical model of the atmosphere for the conditions of observations at the Earth’s surface and at the top of the atmosphere. Cloud is approximated by inverted paraboloid. The molecular absorption is accounted for on the basis of approximation of transmission function by short exponential series (k-distribution method). The specific features of the radiative transfer, caused by the 3D effects of clouds, are considered depending on cloud location in space and its sizes, sensing scheme, and illumination conditions. The simulation results of the brightness fields in the clear sky and in the appearance of isolated cloud are compared. This work was supported in part by the Russian Fund for Basic Research (through the grant no. 12-05-00169).

  4. Impacts of 3-D radiative effects on satellite cloud detection and their consequences on cloud fraction and aerosol optical depth retrievals

    NASA Astrophysics Data System (ADS)

    Yang, Yuekui; di Girolamo, Larry

    2008-02-01

    We present the first examination on how 3-D radiative transfer impacts satellite cloud detection that uses a single visible channel threshold. The 3-D radiative transfer through predefined heterogeneous cloud fields embedded in a range of horizontally homogeneous aerosol fields have been carried out to generate synthetic nadir-viewing satellite images at a wavelength of 0.67 μm. The finest spatial resolution of the cloud field is 30 m. We show that 3-D radiative effects cause significant histogram overlap between the radiance distribution of clear and cloudy pixels, the degree to which depends on many factors (resolution, solar zenith angle, surface reflectance, aerosol optical depth (AOD), cloud top variability, etc.). This overlap precludes the existence of a threshold that can correctly separate all clear pixels from cloudy pixels. The region of clear/cloud radiance overlap includes moderately large (up to 5 in our simulations) cloud optical depths. Purpose-driven cloud masks, defined by different thresholds, are applied to the simulated images to examine their impact on retrieving cloud fraction and AOD. Large (up to 100s of %) systematic errors were observed that depended on the type of cloud mask and the factors that influence the clear/cloud radiance overlap, with a strong dependence on solar zenith angle. Different strategies in computing domain-averaged AOD were performed showing that the domain-averaged BRF from all clear pixels produced the smallest AOD biases with the weakest (but still large) dependence on solar zenith angle. The large dependence of the bias on solar zenith angle has serious implications for climate research that uses satellite cloud and aerosol products.

  5. Europeana and 3D

    NASA Astrophysics Data System (ADS)

    Pletinckx, D.

    2011-09-01

    The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  6. Retrieving Leaf Area Index and Foliage Profiles Through Voxelized 3-D Forest Reconstruction Using Terrestrial Full-Waveform and Dual-Wavelength Echidna Lidars

    NASA Astrophysics Data System (ADS)

    Strahler, A. H.; Yang, X.; Li, Z.; Schaaf, C.; Wang, Z.; Yao, T.; Zhao, F.; Saenz, E.; Paynter, I.; Douglas, E. S.; Chakrabarti, S.; Cook, T.; Martel, J.; Howe, G.; Hewawasam, K.; Jupp, D.; Culvenor, D.; Newnham, G.; Lowell, J.

    2013-12-01

    Measuring and monitoring canopy biophysical parameters provide a baseline for carbon flux studies related to deforestation and disturbance in forest ecosystems. Terrestrial full-waveform lidar systems, such as the Echidna Validation Instrument (EVI) and its successor Dual-Wavelength Echidna Lidar (DWEL), offer rapid, accurate, and automated characterization of forest structure. In this study, we apply a methodology based on voxelized 3-D forest reconstructions built from EVI and DWEL scans to directly estimate two important biophysical parameters: Leaf Area Index (LAI) and foliage profile. Gap probability, apparent reflectance, and volume associated with the laser pulse footprint at the observed range are assigned to the foliage scattering events in the reconstructed point cloud. Leaf angle distribution is accommodated with a simple model based on gap probability with zenith angle as observed in individual scans of the stand. The DWEL instrument, which emits simultaneous laser pulses at 1064 nm and 1548 nm wavelengths, provides a better capability to separate trunk and branch hits from foliage hits due to water absorption by leaf cellular contents at 1548 nm band. We generate voxel datasets of foliage points using a classification methodology solely based on pulse shape for scans collected by EVI and with pulse shape and band ratio for scans collected by DWEL. We then compare the LAIs and foliage profiles retrieved from the voxel datasets of the two instruments at the same red fir site in Sierra National Forest, CA, with each other and with observations from airborne and field measurements. This study further tests the voxelization methodology in obtaining LAI and foliage profiles that are largely free of clumping effects and returns from woody materials in the canopy. These retrievals can provide a valuable 'ground-truth' validation data source for large-footprint spaceborne or airborne lidar systems retrievals.

  7. A computational model that recovers the 3D shape of an object from a single 2D retinal representation.

    PubMed

    Li, Yunfeng; Pizlo, Zygmunt; Steinman, Robert M

    2009-05-01

    Human beings perceive 3D shapes veridically, but the underlying mechanisms remain unknown. The problem of producing veridical shape percepts is computationally difficult because the 3D shapes have to be recovered from 2D retinal images. This paper describes a new model, based on a regularization approach, that does this very well. It uses a new simplicity principle composed of four shape constraints: viz., symmetry, planarity, maximum compactness and minimum surface. Maximum compactness and minimum surface have never been used before. The model was tested with random symmetrical polyhedra. It recovered their 3D shapes from a single randomly-chosen 2D image. Neither learning, nor depth perception, was required. The effectiveness of the maximum compactness and the minimum surface constraints were measured by how well the aspect ratio of the 3D shapes was recovered. These constraints were effective; they recovered the aspect ratio of the 3D shapes very well. Aspect ratios recovered by the model were compared to aspect ratios adjusted by four human observers. They also adjusted aspect ratios very well. In those rare cases, in which the human observers showed large errors in adjusted aspect ratios, their errors were very similar to the errors made by the model. PMID:18621410

  8. The Relative Effectiveness of Varied Visual Testing Formats in Retrieving Information Related to Different Educational Objectives

    ERIC Educational Resources Information Center

    Williams, Jaison; Dwyer, Francis

    2004-01-01

    The purpose of this study is to: (1) examine the relative effectiveness with which different types of visual test formats facilitated information retrieval on tests measuring different educational objectives; (2) measure the effect that prior knowledge had on information retrieval; and (3) to determine whether an interaction existed between prior…

  9. Phase-retrieval ghost imaging of complex-valued objects

    SciTech Connect

    Gong Wenlin; Han Shensheng

    2010-08-15

    An imaging approach, based on ghost imaging, is reported to recover a pure-phase object or a complex-valued object. Our analytical results, which are backed up by numerical simulations, demonstrate that both the complex-valued object and its amplitude-dependent part can be separately and nonlocally reconstructed using this approach. Both effects influencing the quality of reconstructed images and methods to further improve the imaging quality are also discussed.

  10. A model for calculating the errors of 2D bulk analysis relative to the true 3D bulk composition of an object, with application to chondrules

    NASA Astrophysics Data System (ADS)

    Hezel, Dominik C.

    2007-09-01

    Certain problems in Geosciences require knowledge of the chemical bulk composition of objects, such as, for example, minerals or lithic clasts. This 3D bulk chemical composition (bcc) is often difficult to obtain, but if the object is prepared as a thin or thick polished section a 2D bcc can be easily determined using, for example, an electron microprobe. The 2D bcc contains an error relative to the true 3D bcc that is unknown. Here I present a computer program that calculates this error, which is represented as the standard deviation of the 2D bcc relative to the real 3D bcc. A requirement for such calculations is an approximate structure of the 3D object. In petrological applications, the known fabrics of rocks facilitate modeling. The size of the standard deviation depends on (1) the modal abundance of the phases, (2) the element concentration differences between phases and (3) the distribution of the phases, i.e. the homogeneity/heterogeneity of the object considered. A newly introduced parameter " τ" is used as a measure of this homogeneity/heterogeneity. Accessory phases, which do not necessarily appear in 2D thin sections, are a second source of error, in particular if they contain high concentrations of specific elements. An abundance of only 1 vol% of an accessory phase may raise the 3D bcc of an element by up to a factor of ˜8. The code can be queried as to whether broad beam, point, line or area analysis technique is best for obtaining 2D bcc. No general conclusion can be deduced, as the error rates of these techniques depend on the specific structure of the object considered. As an example chondrules—rapidly solidified melt droplets of chondritic meteorites—are used. It is demonstrated that 2D bcc may be used to reveal trends in the chemistry of 3D objects.