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Sample records for dense stereo correspondence

  1. Cloud photogrammetry with dense stereo for fisheye cameras

    Science.gov (United States)

    Beekmans, Christoph; Schneider, Johannes; Läbe, Thomas; Lennefer, Martin; Stachniss, Cyrill; Simmer, Clemens

    2016-11-01

    We present a novel approach for dense 3-D cloud reconstruction above an area of 10 × 10 km2 using two hemispheric sky imagers with fisheye lenses in a stereo setup. We examine an epipolar rectification model designed for fisheye cameras, which allows the use of efficient out-of-the-box dense matching algorithms designed for classical pinhole-type cameras to search for correspondence information at every pixel. The resulting dense point cloud allows to recover a detailed and more complete cloud morphology compared to previous approaches that employed sparse feature-based stereo or assumed geometric constraints on the cloud field. Our approach is very efficient and can be fully automated. From the obtained 3-D shapes, cloud dynamics, size, motion, type and spacing can be derived, and used for radiation closure under cloudy conditions, for example. Fisheye lenses follow a different projection function than classical pinhole-type cameras and provide a large field of view with a single image. However, the computation of dense 3-D information is more complicated and standard implementations for dense 3-D stereo reconstruction cannot be easily applied. Together with an appropriate camera calibration, which includes internal camera geometry, global position and orientation of the stereo camera pair, we use the correspondence information from the stereo matching for dense 3-D stereo reconstruction of clouds located around the cameras. We implement and evaluate the proposed approach using real world data and present two case studies. In the first case, we validate the quality and accuracy of the method by comparing the stereo reconstruction of a stratocumulus layer with reflectivity observations measured by a cloud radar and the cloud-base height estimated from a Lidar-ceilometer. The second case analyzes a rapid cumulus evolution in the presence of strong wind shear.

  2. Hybrid-Based Dense Stereo Matching

    Science.gov (United States)

    Chuang, T. Y.; Ting, H. W.; Jaw, J. J.

    2016-06-01

    Stereo matching generating accurate and dense disparity maps is an indispensable technique for 3D exploitation of imagery in the fields of Computer vision and Photogrammetry. Although numerous solutions and advances have been proposed in the literature, occlusions, disparity discontinuities, sparse texture, image distortion, and illumination changes still lead to problematic issues and await better treatment. In this paper, a hybrid-based method based on semi-global matching is presented to tackle the challenges on dense stereo matching. To ease the sensitiveness of SGM cost aggregation towards penalty parameters, a formal way to provide proper penalty estimates is proposed. To this end, the study manipulates a shape-adaptive cross-based matching with an edge constraint to generate an initial disparity map for penalty estimation. Image edges, indicating the potential locations of occlusions as well as disparity discontinuities, are approved by the edge drawing algorithm to ensure the local support regions not to cover significant disparity changes. Besides, an additional penalty parameter 𝑃𝑒 is imposed onto the energy function of SGM cost aggregation to specifically handle edge pixels. Furthermore, the final disparities of edge pixels are found by weighting both values derived from the SGM cost aggregation and the U-SURF matching, providing more reliable estimates at disparity discontinuity areas. Evaluations on Middlebury stereo benchmarks demonstrate satisfactory performance and reveal the potency of the hybrid-based dense stereo matching method.

  3. Dense image correspondences for computer vision

    CERN Document Server

    Liu, Ce

    2016-01-01

    This book describes the fundamental building-block of many new computer vision systems: dense and robust correspondence estimation. Dense correspondence estimation techniques are now successfully being used to solve a wide range of computer vision problems, very different from the traditional applications such techniques were originally developed to solve. This book introduces the techniques used for establishing correspondences between challenging image pairs, the novel features used to make these techniques robust, and the many problems dense correspondences are now being used to solve. The book provides information to anyone attempting to utilize dense correspondences in order to solve new or existing computer vision problems. The editors describe how to solve many computer vision problems by using dense correspondence estimation. Finally, it surveys resources, code, and data necessary for expediting the development of effective correspondence-based computer vision systems.   ·         Provides i...

  4. A comparative study of fast dense stereo vision algorithms

    NARCIS (Netherlands)

    Sunyoto, H.; Mark, W. van der; Gavrila, D.M.

    2004-01-01

    With recent hardware advances, real-time dense stereo vision becomes increasingly feasible for general-purpose processors. This has important benefits for the intelligent vehicles domain, alleviating object segmentation problems when sensing complex, cluttered traffic scenes. In this paper, we prese

  5. Dense Correspondences across Scenes and Scales.

    Science.gov (United States)

    Tau, Moria; Hassner, Tal

    2016-05-01

    We seek a practical method for establishing dense correspondences between two images with similar content, but possibly different 3D scenes. One of the challenges in designing such a system is the local scale differences of objects appearing in the two images. Previous methods often considered only few image pixels; matching only pixels for which stable scales may be reliably estimated. Recently, others have considered dense correspondences, but with substantial costs associated with generating, storing and matching scale invariant descriptors. Our work is motivated by the observation that pixels in the image have contexts-the pixels around them-which may be exploited in order to reliably estimate local scales. We make the following contributions. (i) We show that scales estimated in sparse interest points may be propagated to neighboring pixels where this information cannot be reliably determined. Doing so allows scale invariant descriptors to be extracted anywhere in the image. (ii) We explore three means for propagating this information: using the scales at detected interest points, using the underlying image information to guide scale propagation in each image separately, and using both images together. Finally, (iii), we provide extensive qualitative and quantitative results, demonstrating that scale propagation allows for accurate dense correspondences to be obtained even between very different images, with little computational costs beyond those required by existing methods.

  6. Local algorithms on dense two-frame stereo matching

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; LI Xuemei; WANG Shuozhen

    2012-01-01

    Stereo matching is a fundamental and crucial problem in computer vision. In the last decades, many researchers have been working on it and made great progress. Generally stereo algorithms can be classified into local methods and global methods. In this paper, the challenges of stereo matching are first introduced, and then we focus on local approaches which have simpler structures and higher efficiency than global ones. Local algorithms generally perform four steps: cost computation, cost aggregation, disparity computation and disparity refinement. Every step is deeply investigated, and most work focuses on cost aggregation. We studied most of the classical local methods and divide them into several classes. The classification well illustrates the development history of local stereo correspondence and shows the essence of local matching along with its important and difficult points. At the end we give the future development trend of local methods.

  7. Binary descriptor-based dense line-scan stereo matching

    Science.gov (United States)

    Valentín, Kristián; Huber-Mörk, Reinhold; Štolc, Svorad

    2017-01-01

    We present a line-scan stereo system and descriptor-based dense stereo matching for high-performance vision applications. The stochastic binary local descriptor (STABLE) descriptor is a local binary descriptor that builds upon the principles of compressed sensing theory. The most important properties of STABLE are the independence of the descriptor length from the matching window size and the possibility that more than one pair of pixels contributes to a single-descriptor bit. Individual descriptor bits are computed by comparing image intensities over pairs of balanced random subsets of pixels chosen from the whole described area. On a synthetic as well as real-world examples, we demonstrate that STABLE provides competitive or superior performance than other state-of-the-art local binary descriptors in the task of dense stereo matching. The real-world example is derived from line-scan binocular stereo imaging, i.e., two line-scan cameras are observing the same object line and 2-D images are generated due to relative motion. We show that STABLE performs significantly better than the census transform and local binary patterns (LBP) in all considered geometric and radiometric distortion categories to be expected in practical applications of stereo vision. Moreover, we show as well that STABLE provides comparable or better matching quality than the binary robust-independent elementary features descriptor. The low computational complexity and flexible memory footprint make STABLE well suited for most hardware architectures. We present quantitative results based on the Middlebury stereo dataset as well as illustrative results for road surface reconstruction.

  8. High accuracy and visibility-consistent dense multiview stereo.

    Science.gov (United States)

    Vu, Hoang-Hiep; Labatut, Patrick; Pons, Jean-Philippe; Keriven, Renaud

    2012-05-01

    Since the initial comparison of Seitz et al., the accuracy of dense multiview stereovision methods has been increasing steadily. A number of limitations, however, make most of these methods not suitable to outdoor scenes taken under uncontrolled imaging conditions. The present work consists of a complete dense multiview stereo pipeline which circumvents these limitations, being able to handle large-scale scenes without sacrificing accuracy. Highly detailed reconstructions are produced within very reasonable time thanks to two key stages in our pipeline: a minimum s-t cut optimization over an adaptive domain that robustly and efficiently filters a quasidense point cloud from outliers and reconstructs an initial surface by integrating visibility constraints, followed by a mesh-based variational refinement that captures small details, smartly handling photo-consistency, regularization, and adaptive resolution. The pipeline has been tested over a wide range of scenes: from classic compact objects taken in a laboratory setting, to outdoor architectural scenes, landscapes, and cultural heritage sites. The accuracy of its reconstructions has also been measured on the dense multiview benchmark proposed by Strecha et al., showing the results to compare more than favorably with the current state-of-the-art methods.

  9. (Almost) Featureless Stereo: Calibration and Dense 3D Reconstruction Using Whole Image Operations

    Science.gov (United States)

    Smelyanskiy, V. N.; Morris, R. D.; Maluf, D. A.; Cheeseman, P.

    2001-01-01

    The conventional approach to shape from stereo is via feature extraction and correspondences. This results in estimates of the camera parameters and a typically spare estimate of the surface. Given a set of calibrated images, a dense surface reconstruction is possible by minimizing the error between the observed image and the image rendered from the estimated surface with respect to the surface model parameters. Given an uncalibrated image and an estimated surface, the camera parameters can be estimated by minimizing the error between the observed and rendered images a function of the camera parameters. We use a very small dense set of matched features to provide camera parameter estimates for the initial dense surface estimate. We then re-estimate the camera parameters as described above, and then re-estimate the surface. This process is iterated. Whilst it can not be proven to converge, we have found that around three iterations results in excellent surface and camera parameters estimates.

  10. Feature-driven deformation for dense correspondence

    Science.gov (United States)

    Ghosh, Deboshmita; Sharf, Andrei; Amenta, Nina

    2009-02-01

    Establishing reliable correspondences between object surfaces is a fundamental operation, required in many contexts such as cleaning up and completing imperfect captured data, texture and deformation trans- fer, shape-space analysis and exploration, and the automatic generation of realistic distributions of objects. We present a method for matching a template to a collection of possibly target meshes. Our method uses a very small number of user-placed landmarks, which we augment with automatically detected feature correspondences, found using spin images. We deform the template onto the data using an ICP-like framework, smoothing the noisy correspondences at each step so as to produce an averaged motion. The deformation uses a dierential representation of the mesh, with which the deformation can be computed at each iteration by solving a sparse linear system. We have applied our algorithm to a variety of data sets. Using only 11 landmarks between a template and one of the scans from the CEASAR data set, we are able to deform the template, and correctly identify and transfer distinctive features, which are not identied by user-supplied landmarks. We have also successfully established correspondences between several scans of monkey skulls, which have dangling triangles, non-manifold vertices, and self intersections. Our algorithm does not require a clean target mesh, and can even generate correspondence without trimming our extraneous pieces from the target mesh, such as scans of teeth.

  11. An empirical comparison of real-time dense stereo approaches for use in the automotive environment

    National Research Council Canada - National Science Library

    Mroz, Filip; Breckon, Toby P

    2012-01-01

    In this work we evaluate the use of several real-time dense stereo algorithms as a passive 3D sensing technology for potential use as part of a driver assistance system or autonomous vehicle guidance...

  12. Adaptive stereo medical image watermarking using non-corresponding blocks.

    Science.gov (United States)

    Mohaghegh, H; Karimi, N; Soroushmehr, S M R; Samavi, S; Najarian, K

    2015-01-01

    Today with the advent of technology in different medical imaging fields, the use of stereoscopic images has increased. Furthermore, with the rapid growth in telemedicine for remote diagnosis, treatment, and surgery, there is a need for watermarking. This is for copyright protection and tracking of digital media. Also, the efficient use of bandwidth for transmission of such data is another concern. In this paper an adaptive watermarking scheme is proposed that considers human visual system in depth perception. Our proposed scheme modifies maximum singular values of wavelet coefficients of stereo pair for embedding watermark bits. Experimental results show high 3D visual quality of watermarked video frames. Moreover, comparison with a compatible state of the art method shows that the proposed method is highly robust against attacks such as AWGN, salt and pepper noise, and JPEG compression.

  13. Dense depth maps from correspondences derived from perceived motion

    Science.gov (United States)

    Kirby, Richard; Whitaker, Ross

    2017-01-01

    Many computer vision applications require finding corresponding points between images and using the corresponding points to estimate disparity. Today's correspondence finding algorithms primarily use image features or pixel intensities common between image pairs. Some 3-D computer vision applications, however, do not produce the desired results using correspondences derived from image features or pixel intensities. Two examples are the multimodal camera rig and the center region of a coaxial camera rig. We present an image correspondence finding technique that aligns pairs of image sequences using optical flow fields. The optical flow fields provide information about the structure and motion of the scene, which are not available in still images but can be used in image alignment. We apply the technique to a dual focal length stereo camera rig consisting of a visible light-infrared camera pair and to a coaxial camera rig. We test our method on real image sequences and compare our results with the state-of-the-art multimodal and structure from motion (SfM) algorithms. Our method produces more accurate depth and scene velocity reconstruction estimates than the state-of-the-art multimodal and SfM algorithms.

  14. Robotic Mapping and Localization with Real-Time Dense Stereo on Reconfigurable Hardware

    Directory of Open Access Journals (Sweden)

    John Kalomiros

    2010-01-01

    Full Text Available A reconfigurable architecture for dense stereo is presented as an observation framework for a real-time implementation of the simultaneous localization and mapping problem in robotics. The reconfigurable sensor detects point features from stereo image pairs to use at the measurement update stage of the procedure. The main hardware blocks are a dense depth stereo accelerator, a left and right image corner detector, and a stage performing left-right consistency check. For the stereo-processor stage, we have implemented and tested a global-matching component based on a maximum-likelihood dynamic programming technique. The system includes a Nios II processor for data control and a USB 2.0 interface for host communication. Remote control is used to guide a vehicle equipped with a stereo head in an indoor environment. The FastSLAM Bayesian algorithm is applied in order to track and update observations and the robot path in real time. The system is assessed using real scene depth detection and public reference data sets. The paper also reports resource usage and a comparison of mapping and localization results with ground truth.

  15. Real-time Detection of Moving Objects from Moving Vehicles Using Dense Stereo and Optical Flow

    Science.gov (United States)

    Talukder, Ashit; Matthies, Larry

    2004-01-01

    Dynamic scene perception is very important for autonomous vehicles operating around other moving vehicles and humans. Most work on real-time object tracking from moving platforms has used sparse features or assumed flat scene structures. We have recently extended a real-time. dense stereo system to include realtime. dense optical flow, enabling more comprehensive dynamic scene analysis. We describe algorithms to robustly estimate 6-DOF robot egomotion in the presence of moving objects using dense flow and dense stereo. We then use dense stereo and egomotion estimates to identify other moving objects while the robot itself is moving. We present results showing accurate egomotion estimation and detection of moving people and vehicles under general 6DOF motion of the robot and independently moving objects. The system runs at 18.3 Hz on a 1.4 GHz Pentium M laptop. computing 160x120 disparity maps and optical flow fields, egomotion, and moving object segmentation. We believe this is a significant step toward general unconstrained dynamic scene analysis for mobile robots, as well as for improved position estimation where GPS is unavailable.

  16. SIFT flow: dense correspondence across scenes and its applications.

    Science.gov (United States)

    Liu, Ce; Yuen, Jenny; Torralba, Antonio

    2011-05-01

    While image alignment has been studied in different areas of computer vision for decades, aligning images depicting different scenes remains a challenging problem. Analogous to optical flow, where an image is aligned to its temporally adjacent frame, we propose SIFT flow, a method to align an image to its nearest neighbors in a large image corpus containing a variety of scenes. The SIFT flow algorithm consists of matching densely sampled, pixelwise SIFT features between two images while preserving spatial discontinuities. The SIFT features allow robust matching across different scene/object appearances, whereas the discontinuity-preserving spatial model allows matching of objects located at different parts of the scene. Experiments show that the proposed approach robustly aligns complex scene pairs containing significant spatial differences. Based on SIFT flow, we propose an alignment-based large database framework for image analysis and synthesis, where image information is transferred from the nearest neighbors to a query image according to the dense scene correspondence. This framework is demonstrated through concrete applications such as motion field prediction from a single image, motion synthesis via object transfer, satellite image registration, and face recognition.

  17. A new combination of monocular and stereo cues for dense disparity estimation

    Science.gov (United States)

    Mao, Miao; Qin, Kaihuai

    2013-07-01

    Disparity estimation is a popular and important topic in computer vision and robotics. Stereo vision is commonly done to complete the task, but most existing methods fail in textureless regions and utilize numerical methods to interpolate into these regions. Monocular features are usually ignored, which may contain helpful depth information. We proposed a novel method combining monocular and stereo cues to compute dense disparities from a pair of images. The whole image regions are categorized into reliable regions (textured and unoccluded) and unreliable regions (textureless or occluded). Stable and accurate disparities can be gained at reliable regions. Then for unreliable regions, we utilize k-means to find the most similar reliable regions in terms of monocular cues. Our method is simple and effective. Experiments show that our method can generate a more accurate disparity map than existing methods from images with large textureless regions, e.g. snow, icebergs.

  18. DASC: Robust Dense Descriptor for Multi-Modal and Multi-Spectral Correspondence Estimation.

    Science.gov (United States)

    Kim, Seungryong; Min, Dongbo; Ham, Bumsub; Do, Minh N; Sohn, Kwanghoon

    2017-09-01

    Establishing dense correspondences between multiple images is a fundamental task in many applications. However, finding a reliable correspondence between multi-modal or multi-spectral images still remains unsolved due to their challenging photometric and geometric variations. In this paper, we propose a novel dense descriptor, called dense adaptive self-correlation (DASC), to estimate dense multi-modal and multi-spectral correspondences. Based on an observation that self-similarity existing within images is robust to imaging modality variations, we define the descriptor with a series of an adaptive self-correlation similarity measure between patches sampled by a randomized receptive field pooling, in which a sampling pattern is obtained using a discriminative learning. The computational redundancy of dense descriptors is dramatically reduced by applying fast edge-aware filtering. Furthermore, in order to address geometric variations including scale and rotation, we propose a geometry-invariant DASC (GI-DASC) descriptor that effectively leverages the DASC through a superpixel-based representation. For a quantitative evaluation of the GI-DASC, we build a novel multi-modal benchmark as varying photometric and geometric conditions. Experimental results demonstrate the outstanding performance of the DASC and GI-DASC in many cases of dense multi-modal and multi-spectral correspondences.

  19. Deep Self-Convolutional Activations Descriptor for Dense Cross-Modal Correspondence

    OpenAIRE

    Kim, Seungryong; Min, Dongbo; Lin, Stephen; Sohn, Kwanghoon

    2016-01-01

    We present a novel descriptor, called deep self-convolutional activations (DeSCA), designed for establishing dense correspondences between images taken under different imaging modalities, such as different spectral ranges or lighting conditions. Motivated by descriptors based on local self-similarity (LSS), we formulate a novel descriptor by leveraging LSS in a deep architecture, leading to better discriminative power and greater robustness to non-rigid image deformations than state-of-the-ar...

  20. A Modified Image Dense Stereo Matching Algorithm%一种改进的立体像对密集点匹配算法

    Institute of Scientific and Technical Information of China (English)

    王瑞; 杨润泽; 尹晓春

    2011-01-01

    文中研究在随机光场照射下基于窗口的密集点匹配算法.针对基于窗口匹配中出现的细节平滑问题,提出了在窗口 内对像素点引入权值参数来提高细节部分测量精度的方法.在匹配前对图像进行校正,使得各极线和图像坐标系的横轴平行,在匹配过程中不需要再计算极线方程,大大提高了匹配的效率.根据待匹配图像的灰度信息和摄像机的内外参数信息,通过求解对应窗口内像素点向量夹角的方式进行双目立体匹配.在试验中,完成了棋盘格图像的密集点匹配,并与典型区域匹配算法进行了匹配效率与视差图效果的对比分析,验证了文中算法在匹配效率和视差图效果方面的优越性.%It studies the random field irradiation window-based dense point matching algorithm. Matching based on window appears for the details of a smooth problem, a pixel in the window on the introduction of weighting parameters to improve the details of the part of the measurement accuracy. Correct the image before the match,making the polar coordinate system parallel to the horizontal axis, in the matching process does not require re-calculation of polar equation, greatly improving the efficiency of matching. According to the grayscale information and the camera parameter information inside and outside, by solving the corresponding pixel angle within the window between vectors conduct stereo matching. In the study, completed an intensive checkerboard image point matching and compared with the typical area of the matching algorithm efficiency and effectiveness of disparity map, verify the superiority of the algorithm in matching efficiency and effect of disparity map.

  1. Dense real-time stereo matching using memory efficient semi-global-matching variant based on FPGAs

    Science.gov (United States)

    Buder, Maximilian

    2012-06-01

    This paper presents a stereo image matching system that takes advantage of a global image matching method. The system is designed to provide depth information for mobile robotic applications. Typical tasks of the proposed system are to assist in obstacle avoidance, SLAM and path planning. Mobile robots pose strong requirements about size, energy consumption, reliability and output quality of the image matching subsystem. Current available systems either rely on active sensors or on local stereo image matching algorithms. The first are only suitable in controlled environments while the second suffer from low quality depth-maps. Top ranking quality results are only achieved by an iterative approach using global image matching and color segmentation techniques which are computationally demanding and therefore difficult to be executed in realtime. Attempts were made to still reach realtime performance with global methods by simplifying the routines. The depth maps are at the end almost comparable to local methods. An equally named semi-global algorithm was proposed earlier that shows both very good image matching results and relatively simple operations. A memory efficient variant of the Semi-Global-Matching algorithm is reviewed and adopted for an implementation based on reconfigurable hardware. The implementation is suitable for realtime execution in the field of robotics. It will be shown that the modified version of the efficient Semi-Global-Matching method is delivering equivalent result compared to the original algorithm based on the Middlebury dataset. The system has proven to be capable of processing VGA sized images with a disparity resolution of 64 pixel at 33 frames per second based on low cost to mid-range hardware. In case the focus is shifted to a higher image resolution, 1024×1024-sized stereo frames may be processed with the same hardware at 10 fps. The disparity resolution settings stay unchanged. A mobile system that covers preprocessing, matching

  2. Multi-object model-based multi-atlas segmentation for rodent brains using dense discrete correspondences

    Science.gov (United States)

    Lee, Joohwi; Kim, Sun Hyung; Styner, Martin

    2016-03-01

    The delineation of rodent brain structures is challenging due to low-contrast multiple cortical and subcortical organs that are closely interfacing to each other. Atlas-based segmentation has been widely employed due to its ability to delineate multiple organs at the same time via image registration. The use of multiple atlases and subsequent label fusion techniques has further improved the robustness and accuracy of atlas-based segmentation. However, the accuracy of atlas-based segmentation is still prone to registration errors; for example, the segmentation of in vivo MR images can be less accurate and robust against image artifacts than the segmentation of post mortem images. In order to improve the accuracy and robustness of atlas-based segmentation, we propose a multi-object, model-based, multi-atlas segmentation method. We first establish spatial correspondences across atlases using a set of dense pseudo-landmark particles. We build a multi-object point distribution model using those particles in order to capture inter- and intra- subject variation among brain structures. The segmentation is obtained by fitting the model into a subject image, followed by label fusion process. Our result shows that the proposed method resulted in greater accuracy than comparable segmentation methods, including a widely used ANTs registration tool.

  3. Stereo matching with Mumford-Shah regularization and occlusion handling.

    Science.gov (United States)

    Ben-Ari, Rami; Sochen, Nir

    2010-11-01

    This paper addresses the problem of correspondence establishment in binocular stereo vision. We suggest a novel spatially continuous approach for stereo matching based on the variational framework. The proposed method suggests a unique regularization term based on Mumford-Shah functional for discontinuity preserving, combined with a new energy functional for occlusion handling. The evaluation process is based on concurrent minimization of two coupled energy functionals, one for domain segmentation (occluded versus visible) and the other for disparity evaluation. In addition to a dense disparity map, our method also provides an estimation for the half-occlusion domain and a discontinuity function allocating the disparity/depth boundaries. Two new constraints are introduced improving the revealed discontinuity map. The experimental tests include a wide range of real data sets from the Middlebury stereo database. The results demonstrate the capability of our method in calculating an accurate disparity function with sharp discontinuities and occlusion map recovery. Significant improvements are shown compared to a recently published variational stereo approach. A comparison on the Middlebury stereo benchmark with subpixel accuracies shows that our method is currently among the top-ranked stereo matching algorithms.

  4. Enhanced Stereo Matching Technique using Image Gradient for Improved Search Time

    Directory of Open Access Journals (Sweden)

    Pratibha Vellanki

    2011-05-01

    Full Text Available Stereo matching algorithms developed from local area based correspondence matching involve extensive search. This paper presents a stereo matching technique for computation of a dense disparity map by trimming down the search time for the local area based correspondence matching. We use constraints such as epipolar line, limiting the disparity, uniqueness and continuity to obtain an initial dense disparity map. We attempt to improvise this map by using color information for matching. A new approach has been discussed which is based on the extension of the continuity constraint for reducing the search time. We use correspondence between rows and gradient of image to compute the disparity. Thus we achieve a good trade off between accuracy and search time.

  5. Approaches for Stereo Matching

    Directory of Open Access Journals (Sweden)

    Takouhi Ozanian

    1995-04-01

    Full Text Available This review focuses on the last decade's development of the computational stereopsis for recovering three-dimensional information. The main components of the stereo analysis are exposed: image acquisition and camera modeling, feature selection, feature matching and disparity interpretation. A brief survey is given of the well known feature selection approaches and the estimation parameters for this selection are mentioned. The difficulties in identifying correspondent locations in the two images are explained. Methods as to how effectively to constrain the search for correct solution of the correspondence problem are discussed, as are strategies for the whole matching process. Reasons for the occurrence of matching errors are considered. Some recently proposed approaches, employing new ideas in the modeling of stereo matching in terms of energy minimization, are described. Acknowledging the importance of computation time for real-time applications, special attention is paid to parallelism as a way to achieve the required level of performance. The development of trinocular stereo analysis as an alternative to the conventional binocular one, is described. Finally a classification based on the test images for verification of the stereo matching algorithms, is supplied.

  6. High Resolution Image Correspondences for Video Post-Production

    Directory of Open Access Journals (Sweden)

    Marcus Magnor

    Full Text Available We present an algorithm for estimating dense image correspondences. Our versatile approach lends itself to various tasks typical for video post-processing, including image morphing, optical flow estimation, stereo rectification, disparity/depth reconstruction, and baseline adjustment. We incorporate recent advances in feature matching, energy minimization, stereo vision, and data clustering into our approach. At the core of our correspondence estimation we use Efficient Belief Propagation for energy minimization. While state-of-the-art algorithms only work on thumbnail-sized images, our novel feature downsampling scheme in combination with a simple, yet efficient data term compression, can cope with high-resolution data. The incorporation of SIFT (Scale-Invariant Feature Transform features into data term computation further resolves matching ambiguities, making long-range correspondence estimation possible. We detect occluded areas by evaluating the correspondence symmetry, we further apply Geodesic matting to automatically determine plausible values in these regions.

  7. High Resolution Image Correspondences for Video Post-Production

    Directory of Open Access Journals (Sweden)

    Marcus Magnor

    2012-12-01

    Full Text Available We present an algorithm for estimating dense image correspondences. Our versatile approach lends itself to various tasks typical for video post-processing, including image morphing, optical flow estimation, stereo rectification, disparity/depth reconstruction, and baseline adjustment. We incorporate recent advances in feature matching, energy minimization, stereo vision, and data clustering into our approach. At the core of our correspondence estimation we use Efficient Belief Propagation for energy minimization. While state-of-the-art algorithms only work on thumbnail-sized images, our novel feature downsampling scheme in combination with a simple, yet efficient data term compression, can cope with high-resolution data. The incorporation of SIFT (Scale-Invariant Feature Transform features into data term computation further resolves matching ambiguities, making long-range correspondence estimation possible. We detect occluded areas by evaluating the correspondence symmetry, we further apply Geodesic matting to automatically determine plausible values in these regions.

  8. Creating high-resolution bare-earth digital elevation models (DEMs) from stereo imagery in an area of densely vegetated deciduous forest using combinations of procedures designed for lidar point cloud filtering

    Science.gov (United States)

    DeWitt, Jessica D.; Warner, Timothy A.; Chirico, Pete; Bergstresser, Sarah

    2017-01-01

    For areas of the world that do not have access to lidar, fine-scale digital elevation models (DEMs) can be photogrammetrically created using globally available high-spatial resolution stereo satellite imagery. The resultant DEM is best termed a digital surface model (DSM) because it includes heights of surface features. In densely vegetated conditions, this inclusion can limit its usefulness in applications requiring a bare-earth DEM. This study explores the use of techniques designed for filtering lidar point clouds to mitigate the elevation artifacts caused by above ground features, within the context of a case study of Prince William Forest Park, Virginia, USA. The influences of land cover and leaf-on vs. leaf-off conditions are investigated, and the accuracy of the raw photogrammetric DSM extracted from leaf-on imagery was between that of a lidar bare-earth DEM and the Shuttle Radar Topography Mission DEM. Although the filtered leaf-on photogrammetric DEM retains some artifacts of the vegetation canopy and may not be useful for some applications, filtering procedures significantly improved the accuracy of the modeled terrain. The accuracy of the DSM extracted in leaf-off conditions was comparable in most areas to the lidar bare-earth DEM and filtering procedures resulted in accuracy comparable of that to the lidar DEM.

  9. Geometry constraints and matching algorithm for lunar rover stereo vision

    Institute of Scientific and Technical Information of China (English)

    HOU Jian; QI Nai-ming

    2005-01-01

    A feature-constrained stereo matching algorithm for lunar rover navigation is presented based on the analysis of the stereo vision system and working environments of lunar rover. In feature-matching phase, edge points are extracted with wavelet transform and are used as the primitives for matching. Then three criterions are utilized in turn to select the correct matching points with the pyramidal searching strategy. As a result,the algorithm finds corresponding points successfully for large numbers of edge points. Area-matching is accomplished under the constraint of edge-matching results,and the correlation is selected as the criterion.Experimental results with real images of natural terrain indicate that the algorithm provides dense disparity maps with fairly high accuracy.

  10. Deblocking of mobile stereo video

    Science.gov (United States)

    Azzari, Lucio; Gotchev, Atanas; Egiazarian, Karen

    2012-02-01

    Most of candidate methods for compression of mobile stereo video apply block-transform based compression based on the H-264 standard with quantization of transform coefficients driven by quantization parameter (QP). The compression ratio and the resulting bit rate are directly determined by the QP level and high compression is achieved for the price of visually noticeable blocking artifacts. Previous studies on perceived quality of mobile stereo video have revealed that blocking artifacts are the most annoying and most influential in the acceptance/rejection of mobile stereo video and can even completely cancel the 3D effect and the corresponding quality added value. In this work, we address the problem of deblocking of mobile stereo video. We modify a powerful non-local transform-domain collaborative filtering method originally developed for denoising of images and video. The method employs grouping of similar block patches residing in spatial and temporal vicinity of a reference block in filtering them collaboratively in a suitable transform domain. We study the most suitable way of finding similar patches in both channels of stereo video and suggest a hybrid four-dimensional transform to process the collected synchronized (stereo) volumes of grouped blocks. The results benefit from the additional correlation available between the left and right channel of the stereo video. Furthermore, addition sharpening is applied through an embedded alpha-rooting in transform domain, which improve the visual appearance of the deblocked frames.

  11. Feature Based Stereo Matching Using Two-Step Expansion

    Directory of Open Access Journals (Sweden)

    Liqiang Wang

    2014-01-01

    Full Text Available This paper proposes a novel method for stereo matching which is based on image features to produce a dense disparity map through two different expansion phases. It can find denser point correspondences than those of the existing seed-growing algorithms, and it has a good performance in short and wide baseline situations. This method supposes that all pixel coordinates in each image segment corresponding to a 3D surface separately satisfy projective geometry of 1D in horizontal axis. Firstly, a state-of-the-art method of feature matching is used to obtain sparse support points and an image segmentation-based prior is employed to assist the first region outspread. Secondly, the first-step expansion is to find more feature correspondences in the uniform region via initial support points, which is based on the invariant cross ratio in 1D projective transformation. In order to find enough point correspondences, we use a regular seed-growing algorithm as the second-step expansion and produce a quasi-dense disparity map. Finally, two different methods are used to obtain dense disparity map from quasi-dense pixel correspondences. Experimental results show the effectiveness of our method.

  12. Dense surface reconstruction with shadows in MIS.

    Science.gov (United States)

    Lin, Bingxiong; Sun, Yu; Qian, Xiaoning

    2013-09-01

    Three-dimensional reconstruction of internal organ surfaces provides useful information for better control and guidance of the operations of surgical tools for minimally invasive surgery (MIS). The current reconstruction techniques using stereo cameras are still challenging due to the difficulties in correspondence matching in MIS, since there is very limited texture but significant specular reflection on organ surfaces. This paper proposes a new approach to overcome the problem by introducing weakly structured light actively casting surgical tool shadows on organ surfaces. The contribution of this paper is twofold: first, we propose a robust approach to extract shadow edges from a sequence of shadowed images; second, we develop a novel field surface interpolation (FSI) approach to obtain an accurate and dense disparity map. Our approach does not rely on texture information and is able to reconstruct accurate 3-D information by exploiting shadows from surgical tools. One advantage is that the point correspondences are directly calculated and no explicit stereo matching is required, which ensures the efficiency of the method. Another advantage is the minimum hardware requirement because only stereo cameras and a separated single-point light source are required. We evaluated the proposed approach using both phantom models and ex vivo images. Based on the experimental results, we achieved the precision of the recovered 3-D surfaces within 0.7 mm for phantom models and 1.2 mm for ex vivo images. The comparison of disparity maps indicates that with the addition of shadows, the proposed method significantly outperforms the state-of-the-art stereo algorithms for MIS.

  13. Parametric dense stereovision implementation on a system-on chip (SoC).

    Science.gov (United States)

    Gardel, Alfredo; Montejo, Pablo; García, Jorge; Bravo, Ignacio; Lázaro, José L

    2012-01-01

    This paper proposes a novel hardware implementation of a dense recovery of stereovision 3D measurements. Traditionally 3D stereo systems have imposed the maximum number of stereo correspondences, introducing a large restriction on artificial vision algorithms. The proposed system-on-chip (SoC) provides great performance and efficiency, with a scalable architecture available for many different situations, addressing real time processing of stereo image flow. Using double buffering techniques properly combined with pipelined processing, the use of reconfigurable hardware achieves a parametrisable SoC which gives the designer the opportunity to decide its right dimension and features. The proposed architecture does not need any external memory because the processing is done as image flow arrives. Our SoC provides 3D data directly without the storage of whole stereo images. Our goal is to obtain high processing speed while maintaining the accuracy of 3D data using minimum resources. Configurable parameters may be controlled by later/parallel stages of the vision algorithm executed on an embedded processor. Considering hardware FPGA clock of 100 MHz, image flows up to 50 frames per second (fps) of dense stereo maps of more than 30,000 depth points could be obtained considering 2 Mpix images, with a minimum initial latency. The implementation of computer vision algorithms on reconfigurable hardware, explicitly low level processing, opens up the prospect of its use in autonomous systems, and they can act as a coprocessor to reconstruct 3D images with high density information in real time.

  14. GPU-based Scalable Volumetric Reconstruction for Multi-view Stereo

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H; Duchaineau, M; Max, N

    2011-09-21

    We present a new scalable volumetric reconstruction algorithm for multi-view stereo using a graphics processing unit (GPU). It is an effectively parallelized GPU algorithm that simultaneously uses a large number of GPU threads, each of which performs voxel carving, in order to integrate depth maps with images from multiple views. Each depth map, triangulated from pair-wise semi-dense correspondences, represents a view-dependent surface of the scene. This algorithm also provides scalability for large-scale scene reconstruction in a high resolution voxel grid by utilizing streaming and parallel computation. The output is a photo-realistic 3D scene model in a volumetric or point-based representation. We demonstrate the effectiveness and the speed of our algorithm with a synthetic scene and real urban/outdoor scenes. Our method can also be integrated with existing multi-view stereo algorithms such as PMVS2 to fill holes or gaps in textureless regions.

  15. Flexible Hardware-Based Stereo Matching

    Directory of Open Access Journals (Sweden)

    2009-02-01

    Full Text Available To enable adaptive stereo vision for hardware-based embedded stereo vision systems, we propose a novel technique for implementing a flexible block size, disparity range, and frame rate. By reusing existing resources of a static architecture, rather than dynamic reconfiguration, our technique is compatible with application specific integrated circuit (ASIC as well as field programmable gate array (FPGA implementations. We present the corresponding block diagrams and their implementation in our hardware-based stereo matching architecture. Furthermore, we show the impact of flexible stereo matching on the generated disparity maps for the sum of absolute differences (SADs, rank, and census transform algorithms. Finally, we discuss the resource usage and achievable performance when synthesized for an Altera Stratix II FPGA.

  16. Flexible Hardware-Based Stereo Matching

    Directory of Open Access Journals (Sweden)

    Steininger Andreas

    2008-01-01

    Full Text Available Abstract To enable adaptive stereo vision for hardware-based embedded stereo vision systems, we propose a novel technique for implementing a flexible block size, disparity range, and frame rate. By reusing existing resources of a static architecture, rather than dynamic reconfiguration, our technique is compatible with application specific integrated circuit (ASIC as well as field programmable gate array (FPGA implementations. We present the corresponding block diagrams and their implementation in our hardware-based stereo matching architecture. Furthermore, we show the impact of flexible stereo matching on the generated disparity maps for the sum of absolute differences (SADs, rank, and census transform algorithms. Finally, we discuss the resource usage and achievable performance when synthesized for an Altera Stratix II FPGA.

  17. Solar Eclipse, STEREO Style

    Science.gov (United States)

    2007-01-01

    There was a transit of the Moon across the face of the Sun - but it could not be seen from Earth. This sight was visible only from the STEREO-B spacecraft in its orbit about the sun, trailing behind the Earth. NASA's STEREO mission consists of two spacecraft launched in October, 2006 to study solar storms. The transit starts at 1:56 am EST and continued for 12 hours until 1:57 pm EST. STEREO-B is currently about 1 million miles from the Earth, 4.4 times farther away from the Moon than we are on Earth. As the result, the Moon will appear 4.4 times smaller than what we are used to. This is still, however, much larger than, say, the planet Venus appeared when it transited the Sun as seen from Earth in 2004. This alignment of STEREO-B and the Moon is not just due to luck. It was arranged with a small tweak to STEREO-B's orbit last December. The transit is quite useful to STEREO scientists for measuring the focus and the amount of scattered light in the STEREO imagers and for determining the pointing of the STEREO coronagraphs. The Sun as it appears in these the images and each frame of the movie is a composite of nearly simultaneous images in four different wavelengths of extreme ultraviolet light that were separated into color channels and then recombined with some level of transparency for each.

  18. Solar Eclipse, STEREO Style

    Science.gov (United States)

    2007-01-01

    There was a transit of the Moon across the face of the Sun - but it could not be seen from Earth. This sight was visible only from the STEREO-B spacecraft in its orbit about the sun, trailing behind the Earth. NASA's STEREO mission consists of two spacecraft launched in October, 2006 to study solar storms. The transit starts at 1:56 am EST and continued for 12 hours until 1:57 pm EST. STEREO-B is currently about 1 million miles from the Earth, 4.4 times farther away from the Moon than we are on Earth. As the result, the Moon will appear 4.4 times smaller than what we are used to. This is still, however, much larger than, say, the planet Venus appeared when it transited the Sun as seen from Earth in 2004. This alignment of STEREO-B and the Moon is not just due to luck. It was arranged with a small tweak to STEREO-B's orbit last December. The transit is quite useful to STEREO scientists for measuring the focus and the amount of scattered light in the STEREO imagers and for determining the pointing of the STEREO coronagraphs. The Sun as it appears in these the images and each frame of the movie is a composite of nearly simultaneous images in four different wavelengths of extreme ultraviolet light that were separated into color channels and then recombined with some level of transparency for each.

  19. Stereo-Based Region-Growing using String Matching

    Science.gov (United States)

    Mandelbaum, Robert; Mintz, Max

    1995-01-01

    We present a novel stereo algorithm based on a coarse texture segmentation preprocessing phase. Matching is performed using a string comparison. Matching sub-strings correspond to matching sequences of textures. Inter-scanline clustering of matching sub-strings yields regions of matching texture. The shape of these regions yield information concerning object's height, width and azimuthal position relative to the camera pair. Hence, rather than the standard dense depth map, the output of this algorithm is a segmentation of objects in the scene. Such a format is useful for the integration of stereo with other sensor modalities on a mobile robotic platform. It is also useful for localization; the height and width of a detected object may be used for landmark recognition, while depth and relative azimuthal location determine pose. The algorithm does not rely on the monotonicity of order of image primitives. Occlusions, exposures, and foreshortening effects are not problematic. The algorithm can deal with certain types of transparencies. It is computationally efficient, and very amenable to parallel implementation. Further, the epipolar constraints may be relaxed to some small but significant degree. A version of the algorithm has been implemented and tested on various types of images. It performs best on random dot stereograms, on images with easily filtered backgrounds (as in synthetic images), and on real scenes with uncontrived backgrounds.

  20. Stereo pairs in Astrophysics

    CERN Document Server

    Vogt, Frédéric

    2011-01-01

    Stereoscopic visualization is seldom used in Astrophysical publications and presentations compared to other scientific fields, e.g., Biochemistry, where it has been recognized as a valuable tool for decades. We put forth the view that stereo pairs can be a useful tool for the Astrophysics community in communicating a truer representation of astrophysical data. Here, we review the main theoretical aspects of stereoscopy, and present a tutorial to easily create stereo pairs using Python. We then describe how stereo pairs provide a way to incorporate 3D data in 2D publications of standard journals. We illustrate the use of stereo pairs with one conceptual and two Astrophysical science examples: an integral field spectroscopy study of a supernova remnant, and numerical simulations of a relativistic AGN jet. We also use these examples to make the case that stereo pairs are not merely an ostentatious way to present data, but an enhancement in the communication of scientific results in publications because they prov...

  1. JAVA Stereo Display Toolkit

    Science.gov (United States)

    Edmonds, Karina

    2008-01-01

    This toolkit provides a common interface for displaying graphical user interface (GUI) components in stereo using either specialized stereo display hardware (e.g., liquid crystal shutter or polarized glasses) or anaglyph display (red/blue glasses) on standard workstation displays. An application using this toolkit will work without modification in either environment, allowing stereo software to reach a wider audience without sacrificing high-quality display on dedicated hardware. The toolkit is written in Java for use with the Swing GUI Toolkit and has cross-platform compatibility. It hooks into the graphics system, allowing any standard Swing component to be displayed in stereo. It uses the OpenGL graphics library to control the stereo hardware and to perform the rendering. It also supports anaglyph and special stereo hardware using the same API (application-program interface), and has the ability to simulate color stereo in anaglyph mode by combining the red band of the left image with the green/blue bands of the right image. This is a low-level toolkit that accomplishes simply the display of components (including the JadeDisplay image display component). It does not include higher-level functions such as disparity adjustment, 3D cursor, or overlays all of which can be built using this toolkit.

  2. LROC NAC Stereo Anaglyphs

    Science.gov (United States)

    Mattson, S.; McEwen, A. S.; Speyerer, E.; Robinson, M. S.

    2012-12-01

    The Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (LROC NAC) acquires high resolution (50 to 200 cm pixel scale) images of the Moon. In operation since June 2009, LROC NAC acquires geometric stereo pairs by rolling off-nadir on subsequent orbits. A new automated processing system currently in development will produce anaglyphs from most of the NAC geometric stereo pairs. An anaglyph is an image formed by placing one image from the stereo pair in the red channel, and the other image from the stereo pair in the green and blue channels, so that together with red-blue or red-cyan glasses, the 3D information in the pair can be readily viewed. These new image products will make qualitative interpretation of the lunar surface in 3D more accessible, without the need for intensive computational resources or special equipment. The LROC NAC is composed of two separate pushbroom CCD cameras (NAC L and R) aligned to increase the full swath width to 5 km from an altitude of 50 km. Development of the anaglyph processing system incorporates stereo viewing geometry, proper alignment of the NAC L and R frames, and optimal contrast normalization of the stereo pair to minimize extreme brightness differences, which can make stereo viewing difficult in an anaglyph. The LROC NAC anaglyph pipeline is based on a similar automated system developed for the HiRISE camera, on the Mars Reconnaissance Orbiter. Improved knowledge of camera pointing and spacecraft position allows for the automatic registration of the L and R frames by map projecting them to a polar stereographic projection. One half of the stereo pair must then be registered to the other so there is no offset in the vertical (y) direction. Stereo viewing depends on parallax only in the horizontal (x) direction. High resolution LROC NAC anaglyphs will be made available to the lunar science community and to the public on the LROC web site (http://lroc.sese.asu.edu).

  3. Parametric Coding of Stereo Audio

    Directory of Open Access Journals (Sweden)

    Erik Schuijers

    2005-06-01

    Full Text Available Parametric-stereo coding is a technique to efficiently code a stereo audio signal as a monaural signal plus a small amount of parametric overhead to describe the stereo image. The stereo properties are analyzed, encoded, and reinstated in a decoder according to spatial psychoacoustical principles. The monaural signal can be encoded using any (conventional audio coder. Experiments show that the parameterized description of spatial properties enables a highly efficient, high-quality stereo audio representation.

  4. Stereo pairs in Astrophysics

    Science.gov (United States)

    Vogt, Frédéric; Wagner, Alexander Y.

    2012-01-01

    Stereoscopic visualization is seldom used in Astrophysical publications and presentations compared to other scientific fields, e.g., Biochemistry, where it has been recognized as a valuable tool for decades. We put forth the view that stereo pairs can be a useful tool for the Astrophysics community in communicating a truer representation of astrophysical data. Here, we review the main theoretical aspects of stereoscopy, and present a tutorial to easily create stereo pairs using Python. We then describe how stereo pairs provide a way to incorporate 3D data in 2D publications of standard journals. We illustrate the use of stereo pairs with one conceptual and two Astrophysical science examples: an integral field spectroscopy study of a supernova remnant, and numerical simulations of a relativistic AGN jet. We also use these examples to make the case that stereo pairs are not merely an ostentatious way to present data, but an enhancement in the communication of scientific results in publications because they provide the reader with a realistic view of multi-dimensional data, be it of observational or theoretical nature. In recognition of the ongoing 3D expansion in the commercial sector, we advocate an increased use of stereo pairs in Astrophysics publications and presentations as a first step towards new interactive and multi-dimensional publication methods.

  5. Alternative confidence measure for local matching stereo algorithms

    CSIR Research Space (South Africa)

    Ndhlovu, T

    2009-11-01

    Full Text Available The authors present a confidence measure applied to individual disparity estimates in local matching stereo correspondence algorithms. It aims at identifying textureless areas, where most local matching algorithms fail. The confidence measure works...

  6. Surrounding Moving Obstacle Detection for Autonomous Driving Using Stereo Vision

    OpenAIRE

    Hao Sun; Huanxin Zou; Shilin Zhou; Cheng Wang; Naser El-Sheimy

    2013-01-01

    Detection and tracking surrounding moving obstacles such as vehicles and pedestrians are crucial for the safety of mobile robotics and autonomous vehicles. This is especially the case in urban driving scenarios. This paper presents a novel framework for surrounding moving obstacles detection using binocular stereo vision. The contributions of our work are threefold. Firstly, a multiview feature matching scheme is presented for simultaneous stereo correspondence and motion correspondence searc...

  7. Axial-Stereo 3-D Optical Metrology for Inner Profile of Pipes Using a Scanning Laser Endoscope.

    Science.gov (United States)

    Gong, Yuanzheng; Johnston, Richard S; Melville, C David; Seibel, Eric J

    As the rapid progress in the development of optoelectronic components and computational power, 3D optical metrology becomes more and more popular in manufacturing and quality control due to its flexibility and high speed. However, most of the optical metrology methods are limited to external surfaces. This paper proposed a new approach to measure tiny internal 3D surfaces with a scanning fiber endoscope and axial-stereo vision algorithm. A dense, accurate point cloud of internally machined threads was generated to compare with its corresponding X-ray 3D data as ground truth, and the quantification was analyzed by Iterative Closest Points algorithm.

  8. Joint depth map and color consistency estimation for stereo images with different illuminations and cameras.

    Science.gov (United States)

    Heo, Yong Seok; Lee, Kyoung Mu; Lee, Sang Uk

    2013-05-01

    Abstract—In this paper, we propose a method that infers both accurate depth maps and color-consistent stereo images for radiometrically varying stereo images. In general, stereo matching and performing color consistency between stereo images are a chicken-and-egg problem since it is not a trivial task to simultaneously achieve both goals. Hence, we have developed an iterative framework in which these two processes can boost each other. First, we transform the input color images to log-chromaticity color space, from which a linear relationship can be established during constructing a joint pdf of transformed left and right color images. From this joint pdf, we can estimate a linear function that relates the corresponding pixels in stereo images. Based on this linear property, we present a new stereo matching cost by combining Mutual Information (MI), SIFT descriptor, and segment-based plane-fitting to robustly find correspondence for stereo image pairs which undergo radiometric variations. Meanwhile, we devise a Stereo Color Histogram Equalization (SCHE) method to produce color-consistent stereo image pairs, which conversely boost the disparity map estimation. Experimental results show that our method produces both accurate depth maps and color-consistent stereo images, even for stereo images with severe radiometric differences.

  9. Application of Stereo Vision to the Reconnection Scaling Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Klarenbeek, Johnny [Los Alamos National Laboratory; Sears, Jason A. [Los Alamos National Laboratory; Gao, Kevin W. [Los Alamos National Laboratory; Intrator, Thomas P. [Los Alamos National Laboratory; Weber, Thomas [Los Alamos National Laboratory

    2012-08-14

    The measurement and simulation of the three-dimensional structure of magnetic reconnection in astrophysical and lab plasmas is a challenging problem. At Los Alamos National Laboratory we use the Reconnection Scaling Experiment (RSX) to model 3D magnetohydrodynamic (MHD) relaxation of plasma filled tubes. These magnetic flux tubes are called flux ropes. In RSX, the 3D structure of the flux ropes is explored with insertable probes. Stereo triangulation can be used to compute the 3D position of a probe from point correspondences in images from two calibrated cameras. While common applications of stereo triangulation include 3D scene reconstruction and robotics navigation, we will investigate the novel application of stereo triangulation in plasma physics to aid reconstruction of 3D data for RSX plasmas. Several challenges will be explored and addressed, such as minimizing 3D reconstruction errors in stereo camera systems and dealing with point correspondence problems.

  10. Panoramic stereo sphere vision

    Science.gov (United States)

    Feng, Weijia; Zhang, Baofeng; Röning, Juha; Zong, Xiaoning; Yi, Tian

    2013-01-01

    Conventional stereo vision systems have a small field of view (FOV) which limits their usefulness for certain applications. While panorama vision is able to "see" in all directions of the observation space, scene depth information is missed because of the mapping from 3D reference coordinates to 2D panoramic image. In this paper, we present an innovative vision system which builds by a special combined fish-eye lenses module, and is capable of producing 3D coordinate information from the whole global observation space and acquiring no blind area 360°×360° panoramic image simultaneously just using single vision equipment with one time static shooting. It is called Panoramic Stereo Sphere Vision (PSSV). We proposed the geometric model, mathematic model and parameters calibration method in this paper. Specifically, video surveillance, robotic autonomous navigation, virtual reality, driving assistance, multiple maneuvering target tracking, automatic mapping of environments and attitude estimation are some of the applications which will benefit from PSSV.

  11. Robust Mosaicking of Stereo Digital Elevation Models from the Ames Stereo Pipeline

    Science.gov (United States)

    Kim, Tae Min; Moratto, Zachary M.; Nefian, Ara Victor

    2010-01-01

    Robust estimation method is proposed to combine multiple observations and create consistent, accurate, dense Digital Elevation Models (DEMs) from lunar orbital imagery. The NASA Ames Intelligent Robotics Group (IRG) aims to produce higher-quality terrain reconstructions of the Moon from Apollo Metric Camera (AMC) data than is currently possible. In particular, IRG makes use of a stereo vision process, the Ames Stereo Pipeline (ASP), to automatically generate DEMs from consecutive AMC image pairs. However, the DEMs currently produced by the ASP often contain errors and inconsistencies due to image noise, shadows, etc. The proposed method addresses this problem by making use of multiple observations and by considering their goodness of fit to improve both the accuracy and robustness of the estimate. The stepwise regression method is applied to estimate the relaxed weight of each observation.

  12. The STEREO Mission

    CERN Document Server

    2008-01-01

    The STEREO mission uses twin heliospheric orbiters to track solar disturbances from their initiation to 1 AU. This book documents the mission, its objectives, the spacecraft that execute it and the instruments that provide the measurements, both remote sensing and in situ. This mission promises to unlock many of the mysteries of how the Sun produces what has become to be known as space weather.

  13. Usability of car stereo.

    Science.gov (United States)

    Razza, Bruno Montanari; Paschoarelli, Luis Carlos

    2012-01-01

    Automotive sound systems vary widely in terms of functions and way of use between different brands and models what can bring difficulties and lack of consistency to the user. This study aimed to analyze the usability of car stereo commonly found in the market. Four products were analyzed by task analysis and after use reports and the results indicate serious usability issues with respect to the form of operation, organization, clarity and quality of information, visibility and readability, among others.

  14. Kinder, gentler stereo

    Science.gov (United States)

    Siegel, Mel; Tobinaga, Yoshikazu; Akiya, Takeo

    1999-05-01

    Not only binocular perspective disparity, but also many secondary binocular and monocular sensory phenomena, contribute to the human sensation of depth. Binocular perspective disparity is notable as the strongest depth perception factor. However means for creating if artificially from flat image pairs are notorious for inducing physical and mental stresses, e.g., 'virtual reality sickness'. Aiming to deliver a less stressful 'kinder gentler stereo (KGS)', we systematically examine the secondary phenomena and their synergistic combination with each other and with binocular perspective disparity. By KGS we mean a stereo capture, rendering, and display paradigm without cue conflicts, without eyewear, without viewing zones, with negligible 'lock-in' time to perceive the image in depth, and with a normal appearance for stereo-deficient viewers. To achieve KGS we employ optical and digital image processing steps that introduce distortions contrary to strict 'geometrical correctness' of binocular perspective but which nevertheless result in increased stereoscopic viewing comfort. We particularly exploit the lower limits of interoccular separation, showing that unexpectedly small disparities stimulate accurate and pleasant depth sensations. Under these circumstances crosstalk is perceived as depth-of-focus rather than as ghosting. This suggests the possibility of radically new approaches to stereoview multiplexing that enable zoneless autostereoscopic display.

  15. Rapid matching of stereo vision based on fringe projection profilometry

    Science.gov (United States)

    Zhang, Ruihua; Xiao, Yi; Cao, Jian; Guo, Hongwei

    2016-09-01

    As the most important core part of stereo vision, there are still many problems to solve in stereo matching technology. For smooth surfaces on which feature points are not easy to extract, this paper adds a projector into stereo vision measurement system based on fringe projection techniques, according to the corresponding point phases which extracted from the left and right camera images are the same, to realize rapid matching of stereo vision. And the mathematical model of measurement system is established and the three-dimensional (3D) surface of the measured object is reconstructed. This measurement method can not only broaden application fields of optical 3D measurement technology, and enrich knowledge achievements in the field of optical 3D measurement, but also provide potential possibility for the commercialized measurement system in practical projects, which has very important scientific research significance and economic value.

  16. Dense Breasts

    Science.gov (United States)

    ... also appear white on mammography, they can be hidden by or within dense breast tissue. Other imaging ... understanding of the possible charges you will incur. Web page review process: This Web page is reviewed ...

  17. Hearing symptoms personal stereos

    Science.gov (United States)

    da Luz, Tiara Santos; Borja, Ana Lúcia Vieira de Freitas

    2012-01-01

    Summary Introduction: Practical and portable the personal stereos if had become almost indispensable accessories in the day the day. Studies disclose that the portable players of music can cause auditory damages in the long run for who hear music in high volume for a drawn out time. Objective: to verify the prevalence of auditory symptoms in users of amplified players and to know its habits of use Method: Observational prospective study of transversal cut carried through in three institutions of education of the city of Salvador BA, being two of public net and one of the private net. 400 students had answered to the questionnaire, of both the sex, between 14 and 30 years that had related the habit to use personal stereos. Results: The symptoms most prevalent had been hyperacusis (43.5%), auricular fullness (30.5%) and humming (27.5), being that the humming is the symptom most present in the population youngest. How much to the daily habits: 62.3% frequent use, 57% in raised intensities, 34% in drawn out periods. An inverse relation between exposition time was verified and the band of age (p = 0,000) and direct with the prevalence of the humming. Conclusion: Although to admit to have knowledge on the damages that the exposition the sound of high intensity can cause the hearing, the daily habits of the young evidence the inadequate use of the portable stereos characterized by long periods of exposition, raised intensities, frequent use and preference for the insertion phones. The high prevalence of symptoms after the use suggests a bigger risk for the hearing of these young. PMID:25991931

  18. Hearing symptoms personal stereos

    Directory of Open Access Journals (Sweden)

    Tiara Santos da Luz1

    2012-01-01

    Full Text Available Introduction: Practical and portable the personal stereos if had become almost indispensable accessories in the day the day. Studies disclose that the portable players of music can cause auditory damages in the long run for who hear music in high volume for a drawn out time. Objective: to verify the prevalence of auditory symptoms in users of amplified players and to know its habits of use. Method: Observational prospective study of transversal cut carried through in three institutions of education of the city of Salvador BA, being two of public net and one of the private net. 400 students had answered to the questionnaire, of both the sex, between 14 and 30 years that had related the habit to use personal stereos. Results: The symptoms most prevalent had been hyperacusis (43.5%, auricular fullness (30.5% and humming (27.5, being that the humming is the symptom most present in the population youngest. How much to the daily habits: 62.3% frequent use, 57% in raised intensities, 34% in drawn out periods. An inverse relation between exposition time was verified and the band of age (p=0,000 and direct with the prevalence of the humming. Conclusion: Although to admit to have knowledge on the damages that the exposition the sound of high intensity can cause the hearing, the daily habits of the young evidence the inadequate use of the portable stereos characterized by long periods of exposition, raised intensities, frequent use and preference for the insertion phones. The high prevalence of symptoms after the use suggests a bigger risk for the hearing of these young.

  19. Foreign correspondence

    CERN Document Server

    Hamilton, John Maxwell

    2013-01-01

    Despite the importance of foreign news, its history, transformation and indeed its future have not been much studied. The scholarly community often calls attention to journalism's shortcomings covering the world, yet the topic has not been systematically examined across countries or over time. The need to redress this neglect and the desire to assess the impact of new media technologies on the future of journalism - including foreign correspondence - provide the motivation for this stimulating, exciting and thought-provoking book. While the old economic models supporting news have crumbled in

  20. Stereo-panoramic Data

    KAUST Repository

    Cutchin, Steve

    2013-03-07

    Systems and methods for automatically generating three-dimensional panoramic images for use in various virtual reality settings are disclosed. One embodiment of the system includes a stereo camera capture device (SCD), a programmable camera controller (PCC) that rotates, orients, and controls the SCD, a robotic maneuvering platform (RMP), and a path and adaptation controller (PAC). In that embodiment, the PAC determines the movement of the system based on an original desired path and input gathered from the SCD during an image capture process.

  1. Stereo Hysteresis Revisited

    Directory of Open Access Journals (Sweden)

    Christopher Tyler

    2012-05-01

    Full Text Available One of the most fascinating phenomena in stereopsis is the profound hysteresis effect reported by Fender and Julesz (1967, in which the depth percept persisted with increasing disparity long past the point at which depth was recovered with decreasing disparity. To control retinal disparity without vergence eye movements, they stabilized the stimuli on the retinas with an eye tracker. I now report that stereo hysteresis can be observed directly in printed stereograms simply by rotating the image. As the stereo image rotates, the horizontal disparities rotate to become vertical, then horizontal with inverted sign, and then vertical again before returning to the original orientation. The depth shows an interesting popout effect, almost as though the depth was turning on and off rapidly, despite the inherently sinusoidal change in the horizontal disparity vector. This stimulus was generated electronically in a circular format so that the random-dot field could be dynamically replaced, eliminating any cue to cyclorotation. Noise density was scaled with eccentricity to fade out the stimulus near fixation. For both the invariant and the dynamic noise, profound hysteresis of several seconds delay was found in six observers. This was far longer than the reaction time to respond to changes in disparity, which was less than a second. Purely horizontal modulation of disparity to match the horizontal vector component of the disparity rotation did not show the popout effect, which thus seems to be a function of the interaction between horizontal and vertical disparities and may be attributable to depth interpolation processes.

  2. Surrounding Moving Obstacle Detection for Autonomous Driving Using Stereo Vision

    Directory of Open Access Journals (Sweden)

    Hao Sun

    2013-06-01

    Full Text Available Detection and tracking surrounding moving obstacles such as vehicles and pedestrians are crucial for the safety of mobile robotics and autonomous vehicles. This is especially the case in urban driving scenarios. This paper presents a novel framework for surrounding moving obstacles detection using binocular stereo vision. The contributions of our work are threefold. Firstly, a multiview feature matching scheme is presented for simultaneous stereo correspondence and motion correspondence searching. Secondly, the multiview geometry constraint derived from the relative camera positions in pairs of consecutive stereo views is exploited for surrounding moving obstacles detection. Thirdly, an adaptive particle filter is proposed for tracking of multiple moving obstacles in surrounding areas. Experimental results from real‐world driving sequences demonstrate the effectiveness and robustness of the proposed framework.

  3. Surrounding Moving Obstacle Detection for Autonomous Driving Using Stereo Vision

    Directory of Open Access Journals (Sweden)

    Hao Sun

    2013-06-01

    Full Text Available Detection and tracking surrounding moving obstacles such as vehicles and pedestrians are crucial for the safety of mobile robotics and autonomous vehicles. This is especially the case in urban driving scenarios. This paper presents a novel framework for surrounding moving obstacles detection using binocular stereo vision. The contributions of our work are threefold. Firstly, a multiview feature matching scheme is presented for simultaneous stereo correspondence and motion correspondence searching. Secondly, the multiview geometry constraint derived from the relative camera positions in pairs of consecutive stereo views is exploited for surrounding moving obstacles detection. Thirdly, an adaptive particle filter is proposed for tracking of multiple moving obstacles in surrounding areas. Experimental results from real-world driving sequences demonstrate the effectiveness and robustness of the proposed framework.

  4. Research on stereo vision odometry

    Science.gov (United States)

    Zhang, Xiaoling; Zhang, Baofeng; Tian, Xiuzhen

    2010-11-01

    The stereo visual odometer in vision based on the navigation system is proposed in the paper. The stereo visual odometer can obtain the motion data to implement the position and attitude estimation of ALV(Autonomous Land Vehicle). Two key technology in the stereo vision odometer are dissertated. The first is using SIFT(Scale Invariant Feature Transform) to extract suitable feature, match points pairs in the feature, and track the feature of fore and after frames of the same point on the object. The second is using matching and tracking to obtain the different 3-D coordinate of the feature of the point on the object, and to compute the motion parameters by motion estimate. The unknown outdoor environment is adopted in the experiment. The results show that the stereo vision odometer is more accurate, and the measurement error dose not increase with the movement distance increasing. It can be used as an important supplement of conventional odometer.

  5. Local Surface Reconstruction from MER images using Stereo Workstation

    Science.gov (United States)

    Shin, Dongjoe; Muller, Jan-Peter

    2010-05-01

    The authors present a semi-automatic workflow that reconstructs the 3D shape of the martian surface from local stereo images delivered by PnCam or NavCam on systems such as the NASA Mars Exploration Rover (MER) Mission and in the future the ESA-NASA ExoMars rover PanCam. The process is initiated with manually selected tiepoints on a stereo workstation which is then followed by a tiepoint refinement, stereo-matching using region growing and Levenberg-Marquardt Algorithm (LMA)-based bundle adjustment processing. The stereo workstation, which is being developed by UCL in collaboration with colleagues at the Jet Propulsion Laboratory (JPL) within the EU FP7 ProVisG project, includes a set of practical GUI-based tools that enable an operator to define a visually correct tiepoint via a stereo display. To achieve platform and graphic hardware independence, the stereo application has been implemented using JPL's JADIS graphic library which is written in JAVA and the remaining processing blocks used in the reconstruction workflow have also been developed as a JAVA package to increase the code re-usability, portability and compatibility. Although initial tiepoints from the stereo workstation are reasonably acceptable as true correspondences, it is often required to employ an optional validity check and/or quality enhancing process. To meet this requirement, the workflow has been designed to include a tiepoint refinement process based on the Adaptive Least Square Correlation (ALSC) matching algorithm so that the initial tiepoints can be further enhanced to sub-pixel precision or rejected if they fail to pass the ALSC matching threshold. Apart from the accuracy of reconstruction, it is obvious that the other criterion to assess the quality of reconstruction is the density (or completeness) of reconstruction, which is not attained in the refinement process. Thus, we re-implemented a stereo region growing process, which is a core matching algorithm within the UCL

  6. Trinocular Stereo Matching Based on Correlations Between Baselines and Disparities

    Institute of Scientific and Technical Information of China (English)

    GUANYepeng; GUWeikang

    2004-01-01

    Gray correlation technique is utilized to take the multi-peak feature points with gray correlation coefficients less than a certain range of maximal correlation coefficient as a potential candidate matching set. There exists the maximal correlation between the correct disparities and their corresponding baselines. A trinocular stereo matching algorithm is proposed based on correlations between the baselines and disparities. After computing the correlations between the baselines and disparities, the unique matches can be determined by maximal correlation coefficient. It is proved that the algorithm proposed is valid and credible by 3-D reconstruction on two pairs of actual natural stereo images.

  7. Problem-oriented stereo vision quality evaluation complex

    Science.gov (United States)

    Sidorchuk, D.; Gusamutdinova, N.; Konovalenko, I.; Ershov, E.

    2015-12-01

    We describe an original low cost hardware setting for efficient testing of stereo vision algorithms. The method uses a combination of a special hardware setup and mathematical model and is easy to construct, precise in applications of our interest. For a known scene we derive its analytical representation, called virtual scene. Using a four point correspondence between the scene and virtual one we compute extrinsic camera parameters, and project virtual scene on the image plane, which is the ground truth for depth map. Another result, presented in this paper, is a new depth map quality metric. Its main purpose is to tune stereo algorithms for particular problem, e.g. obstacle avoidance.

  8. Photometric stereo endoscopy

    Science.gov (United States)

    Parot, Vicente; Lim, Daryl; González, Germán; Traverso, Giovanni; Nishioka, Norman S.; Vakoc, Benjamin J.

    2013-01-01

    Abstract. While color video endoscopy has enabled wide-field examination of the gastrointestinal tract, it often misses or incorrectly classifies lesions. Many of these missed lesions exhibit characteristic three-dimensional surface topographies. An endoscopic system that adds topographical measurements to conventional color imagery could therefore increase lesion detection and improve classification accuracy. We introduce photometric stereo endoscopy (PSE), a technique which allows high spatial frequency components of surface topography to be acquired simultaneously with conventional two-dimensional color imagery. We implement this technique in an endoscopic form factor and demonstrate that it can acquire the topography of small features with complex geometries and heterogeneous optical properties. PSE imaging of ex vivo human gastrointestinal tissue shows that surface topography measurements enable differentiation of abnormal shapes from surrounding normal tissue. Together, these results confirm that the topographical measurements can be obtained with relatively simple hardware in an endoscopic form factor, and suggest the potential of PSE to improve lesion detection and classification in gastrointestinal imaging. PMID:23864015

  9. Binocular stereo vision system based on phase matching

    Science.gov (United States)

    Liu, Huixian; Huang, Shujun; Gao, Nan; Zhang, Zonghua

    2016-11-01

    Binocular stereo vision is an efficient way for three dimensional (3D) profile measurement and has broad applications. Image acquisition, camera calibration, stereo matching, and 3D reconstruction are four main steps. Among them, stereo matching is the most important step that has a significant impact on the final result. In this paper, a new stereo matching technique is proposed to combine the absolute fringe order and the unwrapped phase of every pixel. Different from traditional phase matching method, sinusoidal fringe in two perpendicular directions are projected. It can be realized through the following three steps. Firstly, colored sinusoidal fringe in both horizontal (red fringe) and vertical (blue fringe) are projected on the object to be measured, and captured by two cameras synchronously. The absolute fringe order and the unwrapped phase of each pixel along the two directions are calculated based on the optimum three-fringe numbers selection method. Then, based on the absolute fringe order of the left and right phase maps, stereo matching method is presented. In this process, the same absolute fringe orders in both horizontal and vertical directions are searched to find the corresponding point. Based on this technique, as many as possible pairs of homologous points between two cameras are found to improve the precision of the measurement result. Finally, a 3D measuring system is set up and the 3D reconstruction results are shown. The experimental results show that the proposed method can meet the requirements of high precision for industrial measurements.

  10. 3-Dimentional Mapping Coastal Zone using High Resolution Satellite Stereo Imageries

    Science.gov (United States)

    Hong, Zhonghua; Liu, Fengling; Zhang, Yun

    2014-03-01

    The metropolitan coastal zone mapping is critical for coastal resource management, coastal environmental protection, and coastal sustainable development and planning. The results of geometric processing of a Shanghai coastal zone from 0.7-m-resolution QuickBird Geo stereo images are presented firstly. The geo-positioning accuracy of ground point determination with vendor-provided rigorous physical model (RPM) parameters is evaluated and systematic errors are found when compared with ground control points surveyed by GPS real-time kinematic (GPS-RTK) with 5cm accuracy. A bias-compensation process in image space that applies a RPM bundle adjustment to the RPM-calculated 3D ground points to correct the systematic errors is used to improve the geo-positioning accuracy. And then, a area-based matching (ABM) method is used to generated the densely corresponding points of left and right QuickBird images. With the densely matching points, the 3-dimentinal coordinates of ground points can be calculated by using the refined geometric relationship between image and ground points. At last step, digital surface model (DSM) can be achieved automatically using interpolation method. Accuracies of the DSM as assessed from independent checkpoints (ICPs) are approximately 1.2 m in height.

  11. a Detailed Study about Digital Surface Model Generation Using High Resolution Satellite Stereo Imagery

    Science.gov (United States)

    Gong, K.; Fritsch, D.

    2016-06-01

    Photogrammetry is currently in a process of renaissance, caused by the development of dense stereo matching algorithms to provide very dense Digital Surface Models (DSMs). Moreover, satellite sensors have improved to provide sub-meter or even better Ground Sampling Distances (GSD) in recent years. Therefore, the generation of DSM from spaceborne stereo imagery becomes a vivid research area. This paper presents a comprehensive study about the DSM generation of high resolution satellite data and proposes several methods to implement the approach. The bias-compensated Rational Polynomial Coefficients (RPCs) Bundle Block Adjustment is applied to image orientation and the rectification of stereo scenes is realized based on the Project-Trajectory-Based Epipolarity (PTE) Model. Very dense DSMs are generated from WorldView-2 satellite stereo imagery using the dense image matching module of the C/C++ library LibTsgm. We carry out various tests to evaluate the quality of generated DSMs regarding robustness and precision. The results have verified that the presented pipeline of DSM generation from high resolution satellite imagery is applicable, reliable and very promising.

  12. Automated Placement of Multiple Stereo Cameras

    OpenAIRE

    Malik, Rahul; Bajcsy, Peter

    2008-01-01

    International audience; This paper presents a simulation framework for multiple stereo camera placement. Multiple stereo camera systems are becoming increasingly popular these days. Applications of multiple stereo camera systems such as tele-immersive systems enable cloning of dynamic scenes in real-time and delivering 3D information from multiple geographic locations to everyone for viewing it in virtual (immersive) 3D spaces. In order to make such multi stereo camera systems ubiquitous, sol...

  13. Hearing damage by personal stereo

    DEFF Research Database (Denmark)

    Hammershøi, Dorte; Ordoñez, Rodrigo Pizarro; Reuter, Karen

    2006-01-01

    The technological development within personal stereo systems, such as MP3 players, iPods etc., has changed music listening habits from home entertainment to everyday and everywhere use. The technology has developed considerably, since the introduction of CD walkmen, and high-level low...... of the measurement methods for noise exposure used, and technical issues that may explain the high exposure levels....

  14. Fundamental Matrix of a Stereo Pair, with A Contrario Elimination of Outliers

    Directory of Open Access Journals (Sweden)

    Lionel Moisan

    2016-05-01

    Full Text Available In a stereo image pair, the fundamental matrix encodes the rigidity constraint of the scene. It combines the internal parameters of both cameras (which can be the same and their relative position and orientation. It associates to image points in one view the so-called epipolar line in the other view, which is the locus of projection of the same 3D point, whose particular position on the straight line is determined by its depth. Reducing the correspondence search to a 1D line instead of the 2D image is a large benefit enabling the computation of the dense 3D scene. The estimation of the matrix depends on at least seven pairs of corresponding points in the images. The algorithm discarding outliers presented here is a variant of the classical RANSAC (RANdom SAmple Consensus based on a contrario methodology and proposed first by Moisan and Stival in 2004 under the name ORSA. The distinguishing feature of this algorithm compared to other RANSAC variants is that the measure of validity of a set of point pairs is not its sheer number, but a combination of this number and the geometric precision of the points.

  15. Automatic cloud detection for high resolution satellite stereo images and its application in terrain extraction

    Science.gov (United States)

    Wu, Teng; Hu, Xiangyun; Zhang, Yong; Zhang, Lulin; Tao, Pengjie; Lu, Luping

    2016-11-01

    The automatic extraction of terrain from high-resolution satellite optical images is very difficult under cloudy conditions. Therefore, accurate cloud detection is necessary to fully use the cloud-free parts of images for terrain extraction. This paper addresses automated cloud detection by introducing an image matching based method under a stereo vision framework, and the optimization usage of non-cloudy areas in stereo matching and the generation of digital surface models (DSMs). Given that clouds are often separated from the terrain surface, cloudy areas are extracted by integrating dense matching DSM, worldwide digital elevation model (DEM) (i.e., shuttle radar topography mission (SRTM)) and gray information from the images. This process consists of the following steps: an image based DSM is firstly generated through a multiple primitive multi-image matcher. Once it is aligned with the reference DEM based on common features, places with significant height differences between the DSM and the DEM will suggest the potential cloud covers. Detecting cloud at these places in the images then enables precise cloud delineation. In the final step, elevations of the reference DEM within the cloud covers are assigned to the corresponding region of the DSM to generate a cloud-free DEM. The proposed approach is evaluated with the panchromatic images of the Tianhui satellite and has been successfully used in its daily operation. The cloud detection accuracy for images without snow is as high as 95%. Experimental results demonstrate that the proposed method can significantly improve the usage of the cloudy panchromatic satellite images for terrain extraction.

  16. WASS: An open-source pipeline for 3D stereo reconstruction of ocean waves

    Science.gov (United States)

    Bergamasco, Filippo; Torsello, Andrea; Sclavo, Mauro; Barbariol, Francesco; Benetazzo, Alvise

    2017-10-01

    Stereo 3D reconstruction of ocean waves is gaining more and more popularity in the oceanographic community and industry. Indeed, recent advances of both computer vision algorithms and computer processing power now allow the study of the spatio-temporal wave field with unprecedented accuracy, especially at small scales. Even if simple in theory, multiple details are difficult to be mastered for a practitioner, so that the implementation of a sea-waves 3D reconstruction pipeline is in general considered a complex task. For instance, camera calibration, reliable stereo feature matching and mean sea-plane estimation are all factors for which a well designed implementation can make the difference to obtain valuable results. For this reason, we believe that the open availability of a well tested software package that automates the reconstruction process from stereo images to a 3D point cloud would be a valuable addition for future researches in this area. We present WASS (http://www.dais.unive.it/wass), an Open-Source stereo processing pipeline for sea waves 3D reconstruction. Our tool completely automates all the steps required to estimate dense point clouds from stereo images. Namely, it computes the extrinsic parameters of the stereo rig so that no delicate calibration has to be performed on the field. It implements a fast 3D dense stereo reconstruction procedure based on the consolidated OpenCV library and, lastly, it includes set of filtering techniques both on the disparity map and the produced point cloud to remove the vast majority of erroneous points that can naturally arise while analyzing the optically complex nature of the water surface. In this paper, we describe the architecture of WASS and the internal algorithms involved. The pipeline workflow is shown step-by-step and demonstrated on real datasets acquired at sea.

  17. WASS: an open-source stereo processing pipeline for sea waves 3D reconstruction

    Science.gov (United States)

    Bergamasco, Filippo; Benetazzo, Alvise; Torsello, Andrea; Barbariol, Francesco; Carniel, Sandro; Sclavo, Mauro

    2017-04-01

    Stereo 3D reconstruction of ocean waves is gaining more and more popularity in the oceanographic community. In fact, recent advances of both computer vision algorithms and CPU processing power can now allow the study of the spatio-temporal wave fields with unprecedented accuracy, especially at small scales. Even if simple in theory, multiple details are difficult to be mastered for a practitioner so that the implementation of a 3D reconstruction pipeline is in general considered a complex task. For instance, camera calibration, reliable stereo feature matching and mean sea-plane estimation are all factors for which a well designed implementation can make the difference to obtain valuable results. For this reason, we believe that the open availability of a well-tested software package that automates the steps from stereo images to a 3D point cloud would be a valuable addition for future researches in this area. We present WASS, a completely Open-Source stereo processing pipeline for sea waves 3D reconstruction, available at http://www.dais.unive.it/wass/. Our tool completely automates the recovery of dense point clouds from stereo images by providing three main functionalities. First, WASS can automatically recover the extrinsic parameters of the stereo rig (up to scale) so that no delicate calibration has to be performed on the field. Second, WASS implements a fast 3D dense stereo reconstruction procedure so that an accurate 3D point cloud can be computed from each stereo pair. We rely on the well-consolidated OpenCV library both for the image stereo rectification and disparity map recovery. Lastly, a set of 2D and 3D filtering techniques both on the disparity map and the produced point cloud are implemented to remove the vast majority of erroneous points that can naturally arise while analyzing the optically complex nature of the water surface (examples are sun-glares, large white-capped areas, fog and water areosol, etc). Developed to be as fast as possible, WASS

  18. Stereoscopic motion analysis in densely packed clusters: 3D analysis of the shimmering behaviour in Giant honey bees

    Directory of Open Access Journals (Sweden)

    Hoetzl Thomas

    2011-02-01

    Full Text Available Abstract Background The detailed interpretation of mass phenomena such as human escape panic or swarm behaviour in birds, fish and insects requires detailed analysis of the 3D movements of individual participants. Here, we describe the adaptation of a 3D stereoscopic imaging method to measure the positional coordinates of individual agents in densely packed clusters. The method was applied to study behavioural aspects of shimmering in Giant honeybees, a collective defence behaviour that deters predatory wasps by visual cues, whereby individual bees flip their abdomen upwards in a split second, producing Mexican wave-like patterns. Results Stereoscopic imaging provided non-invasive, automated, simultaneous, in-situ 3D measurements of hundreds of bees on the nest surface regarding their thoracic position and orientation of the body length axis. Segmentation was the basis for the stereo matching, which defined correspondences of individual bees in pairs of stereo images. Stereo-matched "agent bees" were re-identified in subsequent frames by the tracking procedure and triangulated into real-world coordinates. These algorithms were required to calculate the three spatial motion components (dx: horizontal, dy: vertical and dz: towards and from the comb of individual bees over time. Conclusions The method enables the assessment of the 3D positions of individual Giant honeybees, which is not possible with single-view cameras. The method can be applied to distinguish at the individual bee level active movements of the thoraces produced by abdominal flipping from passive motions generated by the moving bee curtain. The data provide evidence that the z-deflections of thoraces are potential cues for colony-intrinsic communication. The method helps to understand the phenomenon of collective decision-making through mechanoceptive synchronization and to associate shimmering with the principles of wave propagation. With further, minor modifications, the method

  19. METHODS OF STEREO PAIR IMAGES FORMATION WITH A GIVEN PARALLAX VALUE

    Directory of Open Access Journals (Sweden)

    Viktoriya G. Chafonova

    2014-11-01

    Full Text Available Two new complementary methods of stereo pair images formation are proposed. The first method is based on finding the maximum correlation between the gradient images of the left and right frames. The second one implies the finding of the shift between two corresponding key points of images for a stereo pair found by a detector of point features. These methods give the possibility to set desired values of vertical and horizontal parallaxes for the selected object in the image. Application of these methods makes it possible to measure the parallax values for the objects on the final stereo pair in pixels and / or the percentage of the total image size. It gives the possibility to predict the possible excesses in parallax values while stereo pair printing or projection. The proposed methods are easily automated after object selection, for which a predetermined value of the horizontal parallax will be exposed. Stereo pair images superposition using the key points takes less than one second. The method with correlation application requires a little bit more computing time, but makes it possible to control and superpose undivided anaglyph image. The proposed methods of stereo pair formation can find their application in programs for editing and processing images of a stereo pair, in the monitoring devices for shooting cameras and in the devices for video sequence quality assessment

  20. Effect of camera temperature variations on stereo-digital image correlation measurements

    KAUST Repository

    Pan, Bing

    2015-11-25

    In laboratory and especially non-laboratory stereo-digital image correlation (stereo-DIC) applications, the extrinsic and intrinsic parameters of the cameras used in the system may change slightly due to the camera warm-up effect and possible variations in ambient temperature. Because these camera parameters are generally calibrated once prior to measurements and considered to be unaltered during the whole measurement period, the changes in these parameters unavoidably induce displacement/strain errors. In this study, the effect of temperature variations on stereo-DIC measurements is investigated experimentally. To quantify the errors associated with camera or ambient temperature changes, surface displacements and strains of a stationary optical quartz glass plate with near-zero thermal expansion were continuously measured using a regular stereo-DIC system. The results confirm that (1) temperature variations in the cameras and ambient environment have a considerable influence on the displacements and strains measured by stereo-DIC due to the slightly altered extrinsic and intrinsic camera parameters; and (2) the corresponding displacement and strain errors correlate with temperature changes. For the specific stereo-DIC configuration used in this work, the temperature-induced strain errors were estimated to be approximately 30–50 με/°C. To minimize the adverse effect of camera temperature variations on stereo-DIC measurements, two simple but effective solutions are suggested.

  1. Effect of camera temperature variations on stereo-digital image correlation measurements.

    Science.gov (United States)

    Pan, Bing; Shi, Wentao; Lubineau, Gilles

    2015-12-01

    In laboratory and especially non-laboratory stereo-digital image correlation (stereo-DIC) applications, the extrinsic and intrinsic parameters of the cameras used in the system may change slightly due to the camera warm-up effect and possible variations in ambient temperature. Because these camera parameters are generally calibrated once prior to measurements and considered to be unaltered during the whole measurement period, the changes in these parameters unavoidably induce displacement/strain errors. In this study, the effect of temperature variations on stereo-DIC measurements is investigated experimentally. To quantify the errors associated with camera or ambient temperature changes, surface displacements and strains of a stationary optical quartz glass plate with near-zero thermal expansion were continuously measured using a regular stereo-DIC system. The results confirm that (1) temperature variations in the cameras and ambient environment have a considerable influence on the displacements and strains measured by stereo-DIC due to the slightly altered extrinsic and intrinsic camera parameters; and (2) the corresponding displacement and strain errors correlate with temperature changes. For the specific stereo-DIC configuration used in this work, the temperature-induced strain errors were estimated to be approximately 30-50 με/°C. To minimize the adverse effect of camera temperature variations on stereo-DIC measurements, two simple but effective solutions are suggested.

  2. Compact stereo endoscopic camera using microprism arrays.

    Science.gov (United States)

    Yang, Sung-Pyo; Kim, Jae-Jun; Jang, Kyung-Won; Song, Weon-Kook; Jeong, Ki-Hun

    2016-03-15

    This work reports a microprism array (MPA) based compact stereo endoscopic camera with a single image sensor. The MPAs were monolithically fabricated by using two-step photolithography and geometry-guided resist reflow to form an appropriate prism angle for stereo image pair formation. The fabricated MPAs were transferred onto a glass substrate with a UV curable resin replica by using polydimethylsiloxane (PDMS) replica molding and then successfully integrated in front of a single camera module. The stereo endoscopic camera with MPA splits an image into two stereo images and successfully demonstrates the binocular disparities between the stereo image pairs for objects with different distances. This stereo endoscopic camera can serve as a compact and 3D imaging platform for medical, industrial, or military uses.

  3. Integrating BC & GC Models In Computing Stereo Disparity As Markov Random Field

    Directory of Open Access Journals (Sweden)

    Hongsheng Zhang

    2006-11-01

    Full Text Available Belief propagation and graph cuts have emerged as powerful tools for computing efficient approximate solution to stereo disparity field modelled as the Markov random field (MRF. These algorithms have provided the best performance based on results on a standard data set. However, employment of the brightness constancy (BC assumption severely limits the range of their applications. Previously, augmenting the BC with gradient constancy (GC assumption has shown to produce a more robust optical flow algorithm. In this paper, these constraints are integrated within the MRF framework to devise an enhanced global method that broadens the application domains for stereo computation. Results of experiments with both semi-synthetic data and more challenging ocean images are presented to illustrate that the proposed method generally outperforms earlier dense optical flow and stereo algorithms.

  4. Non-probabilistic cellular automata-enhanced stereo vision simultaneous localization and mapping

    Science.gov (United States)

    Nalpantidis, Lazaros; Sirakoulis, Georgios Ch; Gasteratos, Antonios

    2011-11-01

    In this paper, a visual non-probabilistic simultaneous localization and mapping (SLAM) algorithm suitable for area measurement applications is proposed. The algorithm uses stereo vision images as its only input and processes them calculating the depth of the scenery, detecting occupied areas and progressively building a map of the environment. The stereo vision-based SLAM algorithm embodies a stereo correspondence algorithm that is tolerant to illumination differentiations, the robust scale- and rotation-invariant feature detection and matching speeded-up robust features method, a computationally effective v-disparity image calculation scheme, a novel map-merging module, as well as a sophisticated cellular automata-based enhancement stage. A moving robot equipped with a stereo camera has been used to gather image sequences and the system has autonomously mapped and measured two different indoor areas.

  5. Assessment Model of Atmosphere Transmitting Influence on High-resolution Airborne SAR Stereo Positioning

    Institute of Scientific and Technical Information of China (English)

    ZHENG Zhaoqing; PANG Lei; CHEN Xuexing

    2008-01-01

    The influence derived from atmosphere transmitting of radar wave, in the application of high-resolution airborne Synthetic Aperture Radar (SAR) stereo positioning, may produce some phase errors, and eventually be intro-duced into positioning model. This paper described the principle of airborne SAR stereo positioning and the error sources of stereo positioning accuracy that arose from atmosphere transmitting, established a corresponding assess-ment model of atmosphere transmitting influence, and testified the model and the assessment principle taking the 1-m resolution airborne SAR images of Zigong City, Sichuan Province in China, as the test dataset. The test result has proved that the assessment model is reliable and reasonable. And, it has shown that the phase error arisen from time delay is the main error source during the atmosphere transmitting, which has much more influences on cross-track di-rection and introduces a stereo positioning error of about eight meters, but less on the along-track direction.

  6. Efficient view synthesis from uncalibrated stereo

    Science.gov (United States)

    Braspenning, Ralph; Op de Beeck, Marc

    2006-02-01

    For multiview auto-stereoscopic 3D displays, available stereo content needs to be converted to multiview content. In this paper we present a method to efficiently synthesize new views based on the two existing views from the stereo input. This method can be implemented in real-time and is also capable of handling uncalibrated stereo input. Good performance is shown compared to state-of-the-art disparity estimation algorithms and view rendering methods.

  7. Phantom-based comparison of the accuracy of point clouds extracted from stereo cameras and laser range scanner

    Science.gov (United States)

    Kumar, Ankur N.; Pheiffer, Thomas S.; Simpson, Amber L.; Thompson, Reid C.; Miga, Michael I.; Dawant, Benoit M.

    2013-03-01

    Using computational models, images acquired pre-operatively can be updated to account for intraoperative brain shift in image-guided surgical (IGS) systems. An optically tracked textured laser range scanner (tLRS) furnishes the 3D coordinates of cortical surface points (3D point clouds) over the surgical field of view and provides a correspondence between these and the pre-operative MR image. However, integration of the acquired tLRS data into a clinically acceptable system compatible throughout the clinical workflow of tumor resection has been challenging. This is because acquiring the tLRS data requires moving the scanner in and out of the surgical field, thus limiting the number of acquisitions. Large differences between acquisitions caused by tumor resection and tissue manipulation make it difficult to establish correspondence and estimate brain motion. An alternative to the tLRS is to use temporally dense feature-rich stereo surgical video data provided by the operating microscope. This allows for quick digitization of the cortical surface in 3D and can help continuously update the IGS system. In order to understand the tradeoffs between these approaches as input to an IGS system, we compare the accuracy of the 3D point clouds extracted from the stereo video system of the surgical microscope and the tLRS for phantom objects in this paper. We show that the stereovision system of the surgical microscope achieves accuracy in the 0.46-1.5mm range on our phantom objects and is a viable alternative to the tLRS for neurosurgical applications.

  8. Multispectral imaging using a stereo camera: concept, design and assessment

    Directory of Open Access Journals (Sweden)

    Mansouri Alamin

    2011-01-01

    Full Text Available Abstract This paper proposes a one-shot six-channel multispectral color image acquisition system using a stereo camera and a pair of optical filters. The two filters from the best pair, selected from among readily available filters such that they modify the sensitivities of the two cameras in such a way that they produce optimal estimation of spectral reflectance and/or color, are placed in front of the two lenses of the stereo camera. The two images acquired from the stereo camera are then registered for pixel-to-pixel correspondence. The spectral reflectance and/or color at each pixel on the scene are estimated from the corresponding camera outputs in the two images. Both simulations and experiments have shown that the proposed system performs well both spectrally and colorimetrically. Since it acquires the multispectral images in one shot, the proposed system can solve the limitations of slow and complex acquisition process, and costliness of the state of the art multispectral imaging systems, leading to its possible uses in widespread applications.

  9. PatchMatch Filter: Edge-Aware Filtering Meets Randomized Search for Visual Correspondence.

    Science.gov (United States)

    Lu, Jiangbo; Li, Yu; Yang, Hongsheng; Min, Dongbo; Eng, Weiyong; Do, Minh N

    2017-09-01

    Though many tasks in computer vision can be formulated elegantly as pixel-labeling problems, a typical challenge discouraging such a discrete formulation is often due to computational efficiency. Recent studies on fast cost volume filtering based on efficient edge-aware filters provide a fast alternative to solve discrete labeling problems, with the complexity independent of the support window size. However, these methods still have to step through the entire cost volume exhaustively, which makes the solution speed scale linearly with the label space size. When the label space is huge or even infinite, which is often the case for (subpixel-accurate) stereo and optical flow estimation, their computational complexity becomes quickly unacceptable. Developed to search approximate nearest neighbors rapidly, the PatchMatch method can significantly reduce the complexity dependency on the search space size. But, its pixel-wise randomized search and fragmented data access within the 3D cost volume seriously hinder the application of efficient cost slice filtering. This paper presents a generic and fast computational framework for general multi-labeling problems called PatchMatch Filter (PMF). We explore effective and efficient strategies to weave together these two fundamental techniques developed in isolation, i.e., PatchMatch-based randomized search and efficient edge-aware image filtering. By decompositing an image into compact superpixels, we also propose superpixel-based novel search strategies that generalize and improve the original PatchMatch method. Further motivated to improve the regularization strength, we propose a simple yet effective cross-scale consistency constraint, which handles labeling estimation for large low-textured regions more reliably than a single-scale PMF algorithm. Focusing on dense correspondence field estimation in this paper, we demonstrate PMF's applications in stereo and optical flow. Our PMF methods achieve top-tier correspondence

  10. Electronics for the STEREO experiment

    CERN Document Server

    Hélaine, V

    2016-01-01

    The STEREO experiment, aiming to probe short baseline neutrino oscillations by precisely measuring reactor anti-neutrino spectrum, is currently under installation. It is located at short distance from the compact research reactor core of the Institut Laue-Langevin, Grenoble, France. Dedicated electronics, hosted in a single $\\mu$TCA crate, were designed for this experiment. In this article, the electronics requirements, architecture and the performances achieved are described. It is shown how intrinsic Pulse Shape Discrimination properties of the liquid scintillator are preserved and how custom adaptable logic is used to improve the muon veto efficiency.

  11. Three-dimensional data-acquiring system fusing active projection and stereo vision

    Science.gov (United States)

    Wu, Jianbo; Zhao, Hong; Tan, Yushan

    2001-09-01

    Combining the active digitizing technique with the passive stereo vision, a novel method is proposed to acquire the 3D data from two 2D images. Based on the principle of stereo vision, and assisting the active dense structure light projecting, the system overcomes the problem of data points matching between two stereo images, which is the most important difficulty occurring in stereo vision. An algorithm based on wavelet transform is proposed here to auto-get the threshold for image segment and extract the grid points. The system described here is mainly applied to digitize the 3D objects in time. Comparing with the general digitizers, it performs the translation from 2D images to 3D data completely, and gets over some shortcomings, such as slow image acquiring and data processing speed, depending on mechanical moving, painting on the object before digitizing, and so on. The system is the same with the non-contact and fast measurement and modeling for the 3D object with freedom surface, and can be employed widely in the fields of Reverse Engineering and CAD/CAM. Experiment proves the efficiency of the new use of shape from stereo vision (SFSV) in engineering.

  12. Stereo Image Reversible Watermarking for Authentication

    Science.gov (United States)

    Luo, Ting; Jiang, Gangyi; Peng, Zongju; Shao, Feng; Yu, Mei

    2015-03-01

    To authenticate stereo image, this paper proposes a stereo image reversible watermarking method for three dimensional television systems. The proposed method can recover the original stereo image without any distortion if stereo image is not tampered. Otherwise, it can authenticate stereo image with the capability of locating tamper. Difference expansion is used to embed authentication bits reversibly into each block for locating tamper. Pixel pairs without resulting in overflow/underflow after expansion are chosen as candidates of embedding locations. In order to avoid transmit big size of embedding location map, the same embedding locations for each block are decided in advance, which adaptively determines the block size. Moreover, in order to resist collage attack, authentication bits generated from each block embedded into its mapping blocks, so that authentication of each block is not independent. Experimental results demonstrate that stereo image can be totally recovered if watermarked stereo image is not modified. Moreover, it proves suitability and stability of the proposed method for tamper location with relationships of stereo images.

  13. Practical intraoperative stereo camera calibration.

    Science.gov (United States)

    Pratt, Philip; Bergeles, Christos; Darzi, Ara; Yang, Guang-Zhong

    2014-01-01

    Many of the currently available stereo endoscopes employed during minimally invasive surgical procedures have shallow depths of field. Consequently, focus settings are adjusted from time to time in order to achieve the best view of the operative workspace. Invalidating any prior calibration procedure, this presents a significant problem for image guidance applications as they typically rely on the calibrated camera parameters for a variety of geometric tasks, including triangulation, registration and scene reconstruction. While recalibration can be performed intraoperatively, this invariably results in a major disruption to workflow, and can be seen to represent a genuine barrier to the widespread adoption of image guidance technologies. The novel solution described herein constructs a model of the stereo endoscope across the continuum of focus settings, thereby reducing the number of degrees of freedom to one, such that a single view of reference geometry will determine the calibration uniquely. No special hardware or access to proprietary interfaces is required, and the method is ready for evaluation during human cases. A thorough quantitative analysis indicates that the resulting intrinsic and extrinsic parameters lead to calibrations as accurate as those derived from multiple pattern views.

  14. Near real-time stereo vision system

    Science.gov (United States)

    Anderson, Charles H. (Inventor); Matthies, Larry H. (Inventor)

    1993-01-01

    The apparatus for a near real-time stereo vision system for use with a robotic vehicle is described. The system is comprised of two cameras mounted on three-axis rotation platforms, image-processing boards, a CPU, and specialized stereo vision algorithms. Bandpass-filtered image pyramids are computed, stereo matching is performed by least-squares correlation, and confidence ranges are estimated by means of Bayes' theorem. In particular, Laplacian image pyramids are built and disparity maps are produced from the 60 x 64 level of the pyramids at rates of up to 2 seconds per image pair. The first autonomous cross-country robotic traverses (of up to 100 meters) have been achieved using the stereo vision system of the present invention with all computing done onboard the vehicle. The overall approach disclosed herein provides a unifying paradigm for practical domain-independent stereo ranging.

  15. Improved Stereo Matching With Boosting Method

    Directory of Open Access Journals (Sweden)

    Shiny B

    2015-06-01

    Full Text Available Abstract This paper presents an approach based on classification for improving the accuracy of stereo matching methods. We propose this method for occlusion handling. This work employs classification of pixels for finding the erroneous disparity values. Due to the wide applications of disparity map in 3D television medical imaging etc the accuracy of disparity map has high significance. An initial disparity map is obtained using local or global stereo matching methods from the input stereo image pair. The various features for classification are computed from the input stereo image pair and the obtained disparity map. Then the computed feature vector is used for classification of pixels by using GentleBoost as the classification method. The erroneous disparity values in the disparity map found by classification are corrected through a completion stage or filling stage. A performance evaluation of stereo matching using AdaBoostM1 RUSBoost Neural networks and GentleBoost is performed.

  16. Stereo Matching Based on Immune Neural Network in Abdomen Reconstruction

    Directory of Open Access Journals (Sweden)

    Huan Liu

    2015-01-01

    Full Text Available Stereo feature matching is a technique that finds an optimal match in two images from the same entity in the three-dimensional world. The stereo correspondence problem is formulated as an optimization task where an energy function, which represents the constraints on the solution, is to be minimized. A novel intelligent biological network (Bio-Net, which involves the human B-T cells immune system into neural network, is proposed in this study in order to learn the robust relationship between the input feature points and the output matched points. A model from input-output data (left reference point-right target point is established. In the experiments, the abdomen reconstructions for different-shape mannequins are then performed by means of the proposed method. The final results are compared and analyzed, which demonstrate that the proposed approach greatly outperforms the single neural network and the conventional matching algorithm in precise. Particularly, as far as time cost and efficiency, the proposed method exhibits its significant promising and potential for improvement. Hence, it is entirely considered as an effective and feasible alternative option for stereo matching.

  17. Dense topological spaces and dense continuity

    Science.gov (United States)

    Aldwoah, Khaled A.

    2013-09-01

    There are several attempts to generalize (or "widen") the concept of topological space. This paper uses equivalence relations to generalize the concept of topological space via the concept of equivalence relations. By the generalization, we can introduce from particular topology on a nonempty set X many new topologies, we call anyone of these new topologies a dense topology. In addition, we formulate some simple properties of dense topologies and study suitable generalizations of the concepts of limit points, closeness and continuity, as well as Jackson, Nörlund and Hahn dense topologies.

  18. HRSC: High resolution stereo camera

    Science.gov (United States)

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

    2009-01-01

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

  19. LIDAR vs dense image matching point clouds in complex urban scenes

    Science.gov (United States)

    Maltezos, Evangelos; Kyrkou, Athanasia; Ioannidis, Charalabos

    2016-08-01

    This study aims to highlight the differences, in terms of robustness and efficiency, of the use of LIDAR point clouds compared to dense image matching (DIM) point clouds at urban areas that contain buildings with complex structure. The application is conducted over an area in the Greek island of Milos using two different types of data: (a) a dense point cloud which extracted by DIM using a variation of the stereo-method semi-global matching (SGM) at RGB digital aerial images, and (b) a georeferenced LIDAR point cloud. For the case of the DIM point cloud, the following steps were applied: aerial triangulation, rectification of the original images to epipolar images, extraction of disparity maps and application of a 3D similarity transformation. The evaluations that were executed included urban and rural areas. At first step, a direct cloud-to-cloud comparison between the georeferenced DIM and LIDAR point clouds was carried out. Then, the corresponding orthoimages generated by the DIM and LIDAR point clouds undergo a quality control. Although the results show that the LIDAR point clouds respond better at such complex scenes compared to DIM point clouds, the latter gave promising results. In this context, the Quality Assurance issue is also discussed so as to be more efficient towards the challenge of the increasingly greater demands for accurate and cost effective applications.

  20. Stereo vision with distance and gradient recognition

    Science.gov (United States)

    Kim, Soo-Hyun; Kang, Suk-Bum; Yang, Tae-Kyu

    2007-12-01

    Robot vision technology is needed for the stable walking, object recognition and the movement to the target spot. By some sensors which use infrared rays and ultrasonic, robot can overcome the urgent state or dangerous time. But stereo vision of three dimensional space would make robot have powerful artificial intelligence. In this paper we consider about the stereo vision for stable and correct movement of a biped robot. When a robot confront with an inclination plane or steps, particular algorithms are needed to go on without failure. This study developed the recognition algorithm of distance and gradient of environment by stereo matching process.

  1. RPC Stereo Processor (rsp) - a Software Package for Digital Surface Model and Orthophoto Generation from Satellite Stereo Imagery

    Science.gov (United States)

    Qin, R.

    2016-06-01

    Large-scale Digital Surface Models (DSM) are very useful for many geoscience and urban applications. Recently developed dense image matching methods have popularized the use of image-based very high resolution DSM. Many commercial/public tools that implement matching methods are available for perspective images, but there are rare handy tools for satellite stereo images. In this paper, a software package, RPC (rational polynomial coefficient) stereo processor (RSP), is introduced for this purpose. RSP implements a full pipeline of DSM and orthophoto generation based on RPC modelled satellite imagery (level 1+), including level 2 rectification, geo-referencing, point cloud generation, pan-sharpen, DSM resampling and ortho-rectification. A modified hierarchical semi-global matching method is used as the current matching strategy. Due to its high memory efficiency and optimized implementation, RSP can be used in normal PC to produce large format DSM and orthophotos. This tool was developed for internal use, and may be acquired by researchers for academic and non-commercial purpose to promote the 3D remote sensing applications.

  2. Structured scene modeling using micro stereo vision system with large field of view

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper presents a method for structured scene modeling using micro stereo vision system with large field of view. The proposed algorithm includes edge detection with Canny detector, line fitting with princi ple axis-based approach, finding corresponding lines using feature-based matching method, and 3D line depth computation.

  3. Stereo Vision and 3D Reconstruction on a Distributed Memory System

    NARCIS (Netherlands)

    Kuijpers, N.H.L.; Paar, G.; Lukkien, J.J.

    1996-01-01

    An important research topic in image processing is stereo vision. The objective is to compute a 3-dimensional representation of some scenery from two 2-dimensional digital images. Constructing a 3-dimensional representation involves finding pairs of pixels from the two images which correspond to the

  4. Stereo Vision and 3D Reconstruction on a Distributed Memory System

    NARCIS (Netherlands)

    Kuijpers, N.H.L.; Paar, G.; Lukkien, J.J.

    1996-01-01

    An important research topic in image processing is stereo vision. The objective is to compute a 3-dimensional representation of some scenery from two 2-dimensional digital images. Constructing a 3-dimensional representation involves finding pairs of pixels from the two images which correspond to the

  5. Stereo 3D spatial phase diagrams

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jinwu, E-mail: kangjw@tsinghua.edu.cn; Liu, Baicheng, E-mail: liubc@tsinghua.edu.cn

    2016-07-15

    Phase diagrams serve as the fundamental guidance in materials science and engineering. Binary P-T-X (pressure–temperature–composition) and multi-component phase diagrams are of complex spatial geometry, which brings difficulty for understanding. The authors constructed 3D stereo binary P-T-X, typical ternary and some quaternary phase diagrams. A phase diagram construction algorithm based on the calculated phase reaction data in PandaT was developed. And the 3D stereo phase diagram of Al-Cu-Mg ternary system is presented. These phase diagrams can be illustrated by wireframe, surface, solid or their mixture, isotherms and isopleths can be generated. All of these can be displayed by the three typical display ways: electronic shutter, polarization and anaglyph (for example red-cyan glasses). Especially, they can be printed out with 3D stereo effect on paper, and watched by the aid of anaglyph glasses, which makes 3D stereo book of phase diagrams come to reality. Compared with the traditional illustration way, the front of phase diagrams protrude from the screen and the back stretches far behind of the screen under 3D stereo display, the spatial structure can be clearly and immediately perceived. These 3D stereo phase diagrams are useful in teaching and research. - Highlights: • Stereo 3D phase diagram database was constructed, including binary P-T-X, ternary, some quaternary and real ternary systems. • The phase diagrams can be watched by active shutter or polarized or anaglyph glasses. • The print phase diagrams retains 3D stereo effect which can be achieved by the aid of anaglyph glasses.

  6. Development of a stereo vision measurement system for a 3D three-axial pneumatic parallel mechanism robot arm.

    Science.gov (United States)

    Chiang, Mao-Hsiung; Lin, Hao-Ting; Hou, Chien-Lun

    2011-01-01

    In this paper, a stereo vision 3D position measurement system for a three-axial pneumatic parallel mechanism robot arm is presented. The stereo vision 3D position measurement system aims to measure the 3D trajectories of the end-effector of the robot arm. To track the end-effector of the robot arm, the circle detection algorithm is used to detect the desired target and the SAD algorithm is used to track the moving target and to search the corresponding target location along the conjugate epipolar line in the stereo pair. After camera calibration, both intrinsic and extrinsic parameters of the stereo rig can be obtained, so images can be rectified according to the camera parameters. Thus, through the epipolar rectification, the stereo matching process is reduced to a horizontal search along the conjugate epipolar line. Finally, 3D trajectories of the end-effector are computed by stereo triangulation. The experimental results show that the stereo vision 3D position measurement system proposed in this paper can successfully track and measure the fifth-order polynomial trajectory and sinusoidal trajectory of the end-effector of the three- axial pneumatic parallel mechanism robot arm.

  7. Dig Hazard Assessment Using a Stereo Pair of Cameras

    Science.gov (United States)

    Rankin, Arturo L.; Trebi-Ollennu, Ashitey

    2012-01-01

    This software evaluates the terrain within reach of a lander s robotic arm for dig hazards using a stereo pair of cameras that are part of the lander s sensor system. A relative level of risk is calculated for a set of dig sectors. There are two versions of this software; one is designed to run onboard a lander as part of the flight software, and the other runs on a PC under Linux as a ground tool that produces the same results generated on the lander, given stereo images acquired by the lander and downlinked to Earth. Onboard dig hazard assessment is accomplished by executing a workspace panorama command sequence. This sequence acquires a set of stereo pairs of images of the terrain the arm can reach, generates a set of candidate dig sectors, and assesses the dig hazard of each candidate dig sector. The 3D perimeter points of candidate dig sectors are generated using configurable parameters. A 3D reconstruction of the terrain in front of the lander is generated using a set of stereo images acquired from the mast cameras. The 3D reconstruction is used to evaluate the dig goodness of each candidate dig sector based on a set of eight metrics. The eight metrics are: 1. The maximum change in elevation in each sector, 2. The elevation standard deviation in each sector, 3. The forward tilt of each sector with respect to the payload frame, 4. The side tilt of each sector with respect to the payload frame, 5. The maximum size of missing data regions in each sector, 6. The percentage of a sector that has missing data, 7. The roughness of each sector, and 8. Monochrome intensity standard deviation of each sector. Each of the eight metrics forms a goodness image layer where the goodness value of each sector ranges from 0 to 1. Goodness values of 0 and 1 correspond to high and low risk, respectively. For each dig sector, the eight goodness values are merged by selecting the lowest one. Including the merged goodness image layer, there are nine goodness image layers for each

  8. Single camera stereo using structure from motion

    Science.gov (United States)

    McBride, Jonah; Snorrason, Magnus; Goodsell, Thomas; Eaton, Ross; Stevens, Mark R.

    2005-05-01

    Mobile robot designers frequently look to computer vision to solve navigation, obstacle avoidance, and object detection problems such as those encountered in parking lot surveillance. Stereo reconstruction is a useful technique in this domain and can be done in two ways. The first requires a fixed stereo camera rig to provide two side-by-side images; the second uses a single camera in motion to provide the images. While stereo rigs can be accurately calibrated in advance, they rely on a fixed baseline distance between the two cameras. The advantage of a single-camera method is the flexibility to change the baseline distance to best match each scenario. This directly increases the robustness of the stereo algorithm and increases the effective range of the system. The challenge comes from accurately rectifying the images into an ideal stereo pair. Structure from motion (SFM) can be used to compute the camera motion between the two images, but its accuracy is limited and small errors can cause rectified images to be misaligned. We present a single-camera stereo system that incorporates a Levenberg-Marquardt minimization of rectification parameters to bring the rectified images into alignment.

  9. Digital elevation modelling using ASTER stereo imagery.

    Science.gov (United States)

    Forkuo, Eric Kwabena

    2010-04-01

    Digital elevation model (DEM) in recent times has become an integral part of national spatial data infrastructure of many countries world-wide due to its invaluable importance. Although DEMs are mostly generated from contours maps, stereo aerial photographs and air-borne and terrestrial laser scanning, the stereo interpretation and auto-correlation from satellite image stereo-pairs such as with SPOT, IRS, and relatively new ASTER imagery is also an effective means of producing DEM data. In this study, terrain elevation data were derived by applying photogrammetric process to ASTER stereo imagery. Also, the quality ofDEMs produced from ASTER stereo imagery was analysed by comparing it with DEM produced from topographic map at a scale of 1:50,000. While analyzing the vertical accuracy of the generated ASTER DEM, fifty ground control points were extracted from the map and overlaid on the DEM. Results indicate that a root-mean-square error in elevation of +/- 14 m was achieved with ASTER stereo image data of good quality. The horizontal accuracy obtained from the ground control points was 14.77, which is within the acceptable range of +/- 7m to +/- 25 m. The generated (15 m) DEM was compared with a 20m, 25m, and a 30 m pixel DEM to the original map. In all, the results proved that, the 15 m DEM conform to the original map DEM than the others. Overall, this analysis proves that, the generated digital terrain model, DEM is acceptable.

  10. SAD-based stereo vision machine on a System-on-Programmable-Chip (SoPC).

    Science.gov (United States)

    Zhang, Xiang; Chen, Zhangwei

    2013-03-04

    This paper, proposes a novel solution for a stereo vision machine based on the System-on-Programmable-Chip (SoPC) architecture. The SOPC technology provides great convenience for accessing many hardware devices such as DDRII, SSRAM, Flash, etc., by IP reuse. The system hardware is implemented in a single FPGA chip involving a 32-bit Nios II microprocessor, which is a configurable soft IP core in charge of managing the image buffer and users' configuration data. The Sum of Absolute Differences (SAD) algorithm is used for dense disparity map computation. The circuits of the algorithmic module are modeled by the Matlab-based DSP Builder. With a set of configuration interfaces, the machine can process many different sizes of stereo pair images. The maximum image size is up to 512 K pixels. This machine is designed to focus on real time stereo vision applications. The stereo vision machine offers good performance and high efficiency in real time. Considering a hardware FPGA clock of 90 MHz, 23 frames of 640 × 480 disparity maps can be obtained in one second with 5 × 5 matching window and maximum 64 disparity pixels.

  11. SAD-Based Stereo Vision Machine on a System-on-Programmable-Chip (SoPC

    Directory of Open Access Journals (Sweden)

    Zhangwei Chen

    2013-03-01

    Full Text Available This paper, proposes a novel solution for a stereo vision machine based on the System-on-Programmable-Chip (SoPC architecture. The SOPC technology provides great convenience for accessing many hardware devices such as DDRII, SSRAM, Flash, etc., by IP reuse. The system hardware is implemented in a single FPGA chip involving a 32-bit Nios II microprocessor, which is a configurable soft IP core in charge of managing the image buffer and users’ configuration data. The Sum of Absolute Differences (SAD algorithm is used for dense disparity map computation. The circuits of the algorithmic module are modeled by the Matlab-based DSP Builder. With a set of configuration interfaces, the machine can process many different sizes of stereo pair images. The maximum image size is up to 512 K pixels. This machine is designed to focus on real time stereo vision applications. The stereo vision machine offers good performance and high efficiency in real time. Considering a hardware FPGA clock of 90 MHz, 23 frames of 640 × 480 disparity maps can be obtained in one second with 5 × 5 matching window and maximum 64 disparity pixels.

  12. Depth-Based Selective Blurring in Stereo Images Using Accelerated Framework

    Science.gov (United States)

    Mukherjee, Subhayan; Guddeti, Ram Mohana Reddy

    2014-09-01

    We propose a hybrid method for stereo disparity estimation by combining block and region-based stereo matching approaches. It generates dense depth maps from disparity measurements of only 18 % image pixels (left or right). The methodology involves segmenting pixel lightness values using fast K-Means implementation, refining segment boundaries using morphological filtering and connected components analysis; then determining boundaries' disparities using sum of absolute differences (SAD) cost function. Complete disparity maps are reconstructed from boundaries' disparities. We consider an application of our method for depth-based selective blurring of non-interest regions of stereo images, using Gaussian blur to de-focus users' non-interest regions. Experiments on Middlebury dataset demonstrate that our method outperforms traditional disparity estimation approaches using SAD and normalized cross correlation by up to 33.6 % and some recent methods by up to 6.1 %. Further, our method is highly parallelizable using CPU-GPU framework based on Java Thread Pool and APARAPI with speed-up of 5.8 for 250 stereo video frames (4,096 × 2,304).

  13. Dense with Sense

    Science.gov (United States)

    Aletras, Anthony H.; Ingkanisorn, W. Patricia; Mancini, Christine; Arai, Andrew E.

    2005-09-01

    Displacement encoding with stimulated echoes (DENSE) with a low encoding strength phase-cycled meta-DENSE readout and a two fold SENSE acceleration ( R = 2) is described. This combination reduces total breath-hold times for increased patient comfort during cardiac regional myocardial contractility studies. Images from phantoms, normal volunteers, and a patient are provided to demonstrate the SENSE-DENSE combination of methods. The overall breath-hold time is halved while preserving strain map quality.

  14. Pengukuran Jarak Berbasiskan Stereo Vision

    Directory of Open Access Journals (Sweden)

    Iman Herwidiana Kartowisastro

    2010-12-01

    Full Text Available Measuring distance from an object can be conducted in a variety of ways, including by making use of distance measuring sensors such as ultrasonic sensors, or using the approach based vision system. This last mode has advantages in terms of flexibility, namely a monitored object has relatively no restrictions characteristic of the materials used at the same time it also has its own difficulties associated with object orientation and state of the room where the object is located. To overcome this problem, so this study examines the possibility of using stereo vision to measure the distance to an object. The system was developed starting from image extraction, information extraction characteristics of the objects contained in the image and visual distance measurement process with 2 separate cameras placed in a distance of 70 cm. The measurement object can be in the range of 50 cm - 130 cm with a percentage error of 5:53%. Lighting conditions (homogeneity and intensity has a great influence on the accuracy of the measurement results. 

  15. STEREO interplanetary shocks and foreshocks

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Cano, X. [Instituto de Geofisica, UNAM, CU, Coyoacan 04510 DF (Mexico); Kajdic, P. [IRAP-University of Toulouse, CNRS, Toulouse (France); Aguilar-Rodriguez, E. [Instituto de Geofisica, UNAM, Morelia (Mexico); Russell, C. T. [ESS and IGPP, University of California, Los Angeles, 603 Charles Young Drive, Los Angeles, CA 90095 (United States); Jian, L. K. [NASA Goddard Space Flight Center, Greenbelt, MD and University of Maryland, College Park, MD (United States); Luhmann, J. G. [SSL, University of California Berkeley (United States)

    2013-06-13

    We use STEREO data to study shocks driven by stream interactions and the waves associated with them. During the years of the extended solar minimum 2007-2010, stream interaction shocks have Mach numbers between 1.1-3.8 and {theta}{sub Bn}{approx}20-86 Degree-Sign . We find a variety of waves, including whistlers and low frequency fluctuations. Upstream whistler waves may be generated at the shock and upstream ultra low frequency (ULF) waves can be driven locally by ion instabilities. The downstream wave spectra can be formed by both, locally generated perturbations, and shock transmitted waves. We find that many quasiperpendicular shocks can be accompanied by ULF wave and ion foreshocks, which is in contrast to Earth's bow shock. Fluctuations downstream of quasi-parallel shocks tend to have larger amplitudes than waves downstream of quasi-perpendicular shocks. Proton foreshocks of shocks driven by stream interactions have extensions dr {<=}0.05 AU. This is smaller than foreshock extensions for ICME driven shocks. The difference in foreshock extensions is related to the fact that ICME driven shocks are formed closer to the Sun and therefore begin to accelerate particles very early in their existence, while stream interaction shocks form at {approx}1 AU and have been producing suprathermal particles for a shorter time.

  16. Modeling and Sensitivity Analysis of Navigation Parameter Errors for Airborne Synthetic Aperture Radar Stereo Geolocation

    Institute of Scientific and Technical Information of China (English)

    PANG Lei; ZHANG Jixian; YAN Qin

    2010-01-01

    For the high-resolution airborne synthetic aperture radar (SAR) stereo geolocation application, the final geolocation accuracy is influenced by various error parameter sources. In this paper, an airborne SAR stereo geolocation parameter error model,involving the parameter errors derived from the navigation system on the flight platform, has been put forward. Moreover, a kind of near-direct method for modeling and sensitivity analysis of navigation parameter errors is also given. This method directly uses the ground reference to calculate the covariance matrix relationship between the parameter errors and the eventual geolocation errors for ground target points. In addition, utilizing true flight track parameters' errors, this paper gave a verification of the method and a corresponding sensitivity analysis for airborne SAR stereo geolocation model and proved its efficiency.

  17. Quasi-Epipolar Resampling of High Resolution Satellite Stereo Imagery for Semi Global Matching

    Science.gov (United States)

    Tatar, N.; Saadatseresht, M.; Arefi, H.; Hadavand, A.

    2015-12-01

    Semi-global matching is a well-known stereo matching algorithm in photogrammetric and computer vision society. Epipolar images are supposed as input of this algorithm. Epipolar geometry of linear array scanners is not a straight line as in case of frame camera. Traditional epipolar resampling algorithms demands for rational polynomial coefficients (RPCs), physical sensor model or ground control points. In this paper we propose a new solution for epipolar resampling method which works without the need for these information. In proposed method, automatic feature extraction algorithms are employed to generate corresponding features for registering stereo pairs. Also original images are divided into small tiles. In this way by omitting the need for extra information, the speed of matching algorithm increased and the need for high temporal memory decreased. Our experiments on GeoEye-1 stereo pair captured over Qom city in Iran demonstrates that the epipolar images are generated with sub-pixel accuracy.

  18. Correlation analysis of couple optical paths for microstereovision with stereo light microscope

    Institute of Scientific and Technical Information of China (English)

    WANG Yuezong; LI Desheng; YU Yaping

    2007-01-01

    A micro stereovision system with a stereo light microscope (SLM) has been applied in micromanipulation systems.There is a coupling connection between two optical paths of a stereo light microscope.The coupling intension corresponds with two factors:the structure of an SLM and the position of an object point in the view of an SLM.In this paper,a correlation function is proposed to describe the coupling intension between the couple optical paths of an SLM.The quantified results are applied to the error analysis of the imaging model.Experiments show that the correlation of the optical paths of a common main objective of stereo light microscope (CMO-SLM) is little more than that of a G-SLM,and the error must be considered when a pinhole imaging model is used to analyze its correlation.

  19. Controlled Correspondence Tracking -

    Data.gov (United States)

    Department of Transportation — This data set contains information on external and internal correspondence addressed to the Secretary, Deputy Secretary, or Chief of Staff. Data include information...

  20. Bssiness Correspondence Translation

    Institute of Scientific and Technical Information of China (English)

    徐静

    2009-01-01

    It is widely-acknowtedged that business correspondence works as a bridge between the writer and the reader.Taking its characteristics into consideration,this essay illustrates how to do business correspondence translation.Only by abiding by all those fcatures can the translator achieve the aim of translation.

  1. Atoms in dense plasmas

    Energy Technology Data Exchange (ETDEWEB)

    More, R.M.

    1986-01-01

    Recent experiments with high-power pulsed lasers have strongly encouraged the development of improved theoretical understanding of highly charged ions in a dense plasma environment. This work examines the theory of dense plasmas with emphasis on general rules which govern matter at extreme high temperature and density. 106 refs., 23 figs.

  2. Quantum dense key distribution

    CERN Document Server

    Degiovanni, I P; Castelletto, S; Rastello, M L; Bovino, F A; Colla, A M; Castagnoli, G C

    2004-01-01

    This paper proposes a new protocol for quantum dense key distribution. This protocol embeds the benefits of a quantum dense coding and a quantum key distribution and is able to generate shared secret keys four times more efficiently than BB84 one. We hereinafter prove the security of this scheme against individual eavesdropping attacks, and we present preliminary experimental results, showing its feasibility.

  3. Multibaseline stereo with active illumination and its application in robot welding

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Object positioning and 3D modeling is not only a promising research direction in robot welding, but also an emphasis research field of machine vision. For objects lacking of textures on its surface, such as welding part, problem of 3D modeling of this kind of object can not be settled by traditional binocular stereo vision. In this paper, an approach to the problem is presented. A multibaseline stereo vision system with four verging configured cameras is proposed. Experiments show that we can get dense data points by the method, the results of surface reconstruction of objects with no matching texture on its surface is good. Experiment results confirmed that the method is valid in solving the problem of 3D surface reconstruction of objects lacking of matching texture.

  4. Optimized stereo matching in binocular three-dimensional measurement system using structured light.

    Science.gov (United States)

    Liu, Kun; Zhou, Changhe; Wei, Shengbin; Wang, Shaoqing; Fan, Xin; Ma, Jianyong

    2014-09-10

    In this paper, we develop an optimized stereo-matching method used in an active binocular three-dimensional measurement system. A traditional dense stereo-matching algorithm is time consuming due to a long search range and the high complexity of a similarity evaluation. We project a binary fringe pattern in combination with a series of N binary band limited patterns. In order to prune the search range, we execute an initial matching before exhaustive matching and evaluate a similarity measure using logical comparison instead of a complicated floating-point operation. Finally, an accurate point cloud can be obtained by triangulation methods and subpixel interpolation. The experiment results verify the computational efficiency and matching accuracy of the method.

  5. Electrophysiological correlates of binocular stereo depth without binocular disparities.

    Directory of Open Access Journals (Sweden)

    Karoline Spang

    Full Text Available A small region of background presented to only one eye in an otherwise binocular display may, under certain conditions, be resolved in the visual system by interpreting the region as a small gap between two similar objects placed at different depths, with the gap hidden in one eye by parallax. This has been called monocular gap stereopsis. We investigated the electrophysiological correlate of this type of stereopsis by means of sum potential recordings in 12 observers, comparing VEP's for this stimulus ("Gillam Stereo", Author BG has strong reservations about this term with those for similar stimuli containing disparity based depth and with no depth (flat. In addition we included several control stimuli. The results show a pronounced early negative potential at a latency of around 170 ms (N170 for all stimuli containing non- identical elements, be they a difference caused by binocular disparity or by completely unmatched monocular contours. A second negative potential with latency around 270 ms (N270, on the other hand, is present only with stimuli leading to fusion and the perception of depth. This second component is similar for disparity-based stereopsis and monocular gap, or "Gillam Stereo" although slightly more pronounced for the former. We conjecture that the first component is related to the detection of differences between the images of the two eyes that may then either be fused, leading to stereopsis and the corresponding second potential, or else to inhibition and rivalry without a later trace in the VEP. The finding that that "Gillam Stereo" leads to cortical responses at the same short latencies as disparity based stereopsis indicates that it may partly rely on quite early cortical mechanisms.

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

    Science.gov (United States)

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

    2015-03-01

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

  7. Vector lifting schemes for stereo image coding.

    Science.gov (United States)

    Kaaniche, Mounir; Benazza-Benyahia, Amel; Pesquet-Popescu, Béatrice; Pesquet, Jean-Christophe

    2009-11-01

    Many research efforts have been devoted to the improvement of stereo image coding techniques for storage or transmission. In this paper, we are mainly interested in lossy-to-lossless coding schemes for stereo images allowing progressive reconstruction. The most commonly used approaches for stereo compression are based on disparity compensation techniques. The basic principle involved in this technique first consists of estimating the disparity map. Then, one image is considered as a reference and the other is predicted in order to generate a residual image. In this paper, we propose a novel approach, based on vector lifting schemes (VLS), which offers the advantage of generating two compact multiresolution representations of the left and the right views. We present two versions of this new scheme. A theoretical analysis of the performance of the considered VLS is also conducted. Experimental results indicate a significant improvement using the proposed structures compared with conventional methods.

  8. Age is highly associated with stereo blindness among surgeons

    DEFF Research Database (Denmark)

    Fergo, Charlotte; Burcharth, Jakob; Pommergaard, Hans-Christian

    2016-01-01

    BACKGROUND: The prevalence of stereo blindness in the general population varies greatly within a range of 1-30 %. Stereo vision adds an extra dimension to aid depth perception and gives a binocular advantage in task completion. Lack of depth perception may lower surgical performance, potentially...... affecting surgical outcome. 3D laparoscopy offers stereoscopic vision of the operative field to improve depth perception and is being introduced to several surgical specialties; however, a normal stereo vision is a prerequisite. The aim of this study was to establish the prevalence of stereo blindness among...... and stereo tested by the use of the Random Dot E stereo test. Upon stereo testing, a demographic questionnaire was completed. Multivariate logistic regression analysis was employed to assess the association between stereo blindness and the variables resulting from the univariate analysis. RESULTS: Three...

  9. A Point Cloud Alignment Algorithm Based on Stereo Vision Using Random Pattern Projection

    Directory of Open Access Journals (Sweden)

    Chen-Sheng Chen

    2016-03-01

    Full Text Available This paper proposes a point cloud alignment algorithm based on stereo vision using Random Pattern Projection (RPP. In the application of stereo vision, it is rather difficult to find correspondences between stereo images of texture-less objects. To overcome this issue, RPP is used to enhance the object’s features, thus increasing the accuracy of the identified correspondences of the stereo images. In the 3D alignment algorithm, the down sample technique is used to filter out the outliers of the point cloud data to improve system efficiency. Furthermore, the extracted features of the down sample point cloud data were applied in the matching process. Finally, the object’s pose was estimated by the alignment algorithm based on object features. In experiments, the maximum error and standard deviation of rotation are respectively about 0.031°and 0.199°, while the maximum error and standard deviation of translation are respectively about 0.565 mm and 0.902 mm . The execution time for pose estimation is about 230ms.

  10. Wide baseline stereo matching based on double topological relationship consistency

    Science.gov (United States)

    Zou, Xiaohong; Liu, Bin; Song, Xiaoxue; Liu, Yang

    2009-07-01

    Stereo matching is one of the most important branches in computer vision. In this paper, an algorithm is proposed for wide-baseline stereo vision matching. Here, a novel scheme is presented called double topological relationship consistency (DCTR). The combination of double topological configuration includes the consistency of first topological relationship (CFTR) and the consistency of second topological relationship (CSTR). It not only sets up a more advanced model on matching, but discards mismatches by iteratively computing the fitness of the feature matches and overcomes many problems of traditional methods depending on the powerful invariance to changes in the scale, rotation or illumination across large view changes and even occlusions. Experimental examples are shown where the two cameras have been located in very different orientations. Also, epipolar geometry can be recovered using RANSAC by far the most widely method adopted possibly. By the method, we can obtain correspondences with high precision on wide baseline matching problems. Finally, the effectiveness and reliability of this method are demonstrated in wide-baseline experiments on the image pairs.

  11. Dsm Based Orientation of Large Stereo Satellite Image Blocks

    Science.gov (United States)

    d'Angelo, P.; Reinartz, P.

    2012-07-01

    High resolution stereo satellite imagery is well suited for the creation of digital surface models (DSM). A system for highly automated and operational DSM and orthoimage generation based on CARTOSAT-1 imagery is presented, with emphasis on fully automated georeferencing. The proposed system processes level-1 stereo scenes using the rational polynomial coefficients (RPC) universal sensor model. The RPC are derived from orbit and attitude information and have a much lower accuracy than the ground resolution of approximately 2.5 m. In order to use the images for orthorectification or DSM generation, an affine RPC correction is required. In this paper, GCP are automatically derived from lower resolution reference datasets (Landsat ETM+ Geocover and SRTM DSM). The traditional method of collecting the lateral position from a reference image and interpolating the corresponding height from the DEM ignores the higher lateral accuracy of the SRTM dataset. Our method avoids this drawback by using a RPC correction based on DSM alignment, resulting in improved geolocation of both DSM and ortho images. Scene based method and a bundle block adjustment based correction are developed and evaluated for a test site covering the nothern part of Italy, for which 405 Cartosat-1 Stereopairs are available. Both methods are tested against independent ground truth. Checks against this ground truth indicate a lateral error of 10 meters.

  12. Correspondence Differential Ghost Imaging

    CERN Document Server

    Li, Ming-Fei; Luo, Kai-Hong; Wu, Ling-An; Fan, Heng

    2013-01-01

    Experimental data with digital masks and a theoretical analysis are presented for a nonlocal imaging scheme that we name correspondence differential ghost imaging (CDGI). It is shown that by conditional averaging of the information from the reference detector but with the negative signals inverted, the quality of the reconstructed images is, in general, superior to all other ghost imaging (GI) methods to date. The advantages of both differential GI and correspondence GI are combined, plus less data and shorter computation time are required to obtain equivalent quality images under the same conditions. This CDGI method offers a general approach applicable to all GI techniques, especially when objects with continuous gray tones are involved.

  13. STU/QCD Correspondence

    CERN Document Server

    Sadeghi, Jafar

    2012-01-01

    In this review article we consider a special case of D=5, $\\mathcal{N}=2$ supergravity called the STU model. We apply the gauge/gravity correspondence to the STU model to gain insight into properties of the quark-gluon plasma. Given that the quark-gluon plasma is in reality described by QCD, therefore we call our study STU/QCD correspondence. First, we investigate the thermodynamics and hydrodynamics of the STU background. Then we use dual picture of the theory, which is type IIB string theory, to obtain the drag force and jet-quenching parameter of an external probe quark.

  14. Stereoselectivity in metallocene-catalyzed coordination polymerization of renewable methylene butyrolactones: From stereo-random to stereo-perfect polymers

    KAUST Repository

    Chen, Xia

    2012-05-02

    Coordination polymerization of renewable α-methylene-γ-(methyl) butyrolactones by chiral C 2-symmetric zirconocene catalysts produces stereo-random, highly stereo-regular, or perfectly stereo-regular polymers, depending on the monomer and catalyst structures. Computational studies yield a fundamental understanding of the stereocontrol mechanism governing these new polymerization reactions mediated by chiral metallocenium catalysts. © 2012 American Chemical Society.

  15. Visualization of the 3-D topography of the optic nerve head through a passive stereo vision model

    Science.gov (United States)

    Ramirez, Juan M.; Mitra, Sunanda; Morales, Jose

    1999-01-01

    This paper describes a system for surface recovery and visualization of the 3D topography of the optic nerve head, as support of early diagnosis and follow up to glaucoma. In stereo vision, depth information is obtained from triangulation of corresponding points in a pair of stereo images. In this paper, the use of the cepstrum transformation as a disparity measurement technique between corresponding windows of different block sizes is described. This measurement process is embedded within a coarse-to-fine depth-from-stereo algorithm, providing an initial range map with the depth information encoded as gray levels. These sparse depth data are processed through a cubic B-spline interpolation technique in order to obtain a smoother representation. This methodology is being especially refined to be used with medical images for clinical evaluation of some eye diseases such as open angle glaucoma, and is currently under testing for clinical evaluation and analysis of reproducibility and accuracy.

  16. Head Pose Estimation from Passive Stereo Images

    DEFF Research Database (Denmark)

    Breitenstein, Michael D.; Jensen, Jeppe; Høilund, Carsten

    2009-01-01

    function. Our algorithm incorporates 2D and 3D cues to make the system robust to low-quality range images acquired by passive stereo systems. It handles large pose variations (of ±90 ° yaw and ±45 ° pitch rotation) and facial variations due to expressions or accessories. For a maximally allowed error of 30...

  17. Artistic Stereo Imaging by Edge Preserving Smoothing

    NARCIS (Netherlands)

    Papari, Giuseppe; Campisi, Patrizio; Callet, Patrick Le; Petkov, Nicolai

    2009-01-01

    Stereo imaging is an important area of image and video processing, with exploding progress in the last decades. An open issue in this field is the understanding of the conditions under which the straightforward application of a given image processing operator to both the left and right image of a st

  18. The potential risk of personal stereo players

    DEFF Research Database (Denmark)

    Hammershøi, Dorte; Ordoñez, Rodrigo Pizarro; Reuter, Karen

    2010-01-01

    The technological development within personal stereo systems, such as MP3 players, e. g. iPods, has changed music listening habits from home entertainment to everyday and everywhere use. The technology has developed considerably, since the introduction of cassette players and CD walkmen. High...

  19. The potential risk of personal stereo players

    DEFF Research Database (Denmark)

    Hammershøi, Dorte; Ordoñez, Rodrigo Pizarro; Reuter, Karen

    2010-01-01

    The technological development within personal stereo systems,such as MP3 players, e. g. iPods, has changed music listening habits from home entertainment to everyday and everywhere use. The technology has developed considerably, since the introduction of cassette players and CD walkmen. High...

  20. Artistic Stereo Imaging by Edge Preserving Smoothing

    NARCIS (Netherlands)

    Papari, Giuseppe; Campisi, Patrizio; Callet, Patrick Le; Petkov, Nicolai

    2009-01-01

    Stereo imaging is an important area of image and video processing, with exploding progress in the last decades. An open issue in this field is the understanding of the conditions under which the straightforward application of a given image processing operator to both the left and right image of a

  1. Accuracy and robustness evaluation in stereo matching

    Science.gov (United States)

    Nguyen, Duc M.; Hanca, Jan; Lu, Shao-Ping; Schelkens, Peter; Munteanu, Adrian

    2016-09-01

    Stereo matching has received a lot of attention from the computer vision community, thanks to its wide range of applications. Despite of the large variety of algorithms that have been proposed so far, it is not trivial to select suitable algorithms for the construction of practical systems. One of the main problems is that many algorithms lack sufficient robustness when employed in various operational conditions. This problem is due to the fact that most of the proposed methods in the literature are usually tested and tuned to perform well on one specific dataset. To alleviate this problem, an extensive evaluation in terms of accuracy and robustness of state-of-the-art stereo matching algorithms is presented. Three datasets (Middlebury, KITTI, and MPEG FTV) representing different operational conditions are employed. Based on the analysis, improvements over existing algorithms have been proposed. The experimental results show that our improved versions of cross-based and cost volume filtering algorithms outperform the original versions with large margins on Middlebury and KITTI datasets. In addition, the latter of the two proposed algorithms ranks itself among the best local stereo matching approaches on the KITTI benchmark. Under evaluations using specific settings for depth-image-based-rendering applications, our improved belief propagation algorithm is less complex than MPEG's FTV depth estimation reference software (DERS), while yielding similar depth estimation performance. Finally, several conclusions on stereo matching algorithms are also presented.

  2. System for clinical photometric stereo endoscopy

    Science.gov (United States)

    Durr, Nicholas J.; González, Germán.; Lim, Daryl; Traverso, Giovanni; Nishioka, Norman S.; Vakoc, Benjamin J.; Parot, Vicente

    2014-02-01

    Photometric stereo endoscopy is a technique that captures information about the high-spatial-frequency topography of the field of view simultaneously with a conventional color image. Here we describe a system that will enable photometric stereo endoscopy to be clinically evaluated in the large intestine of human patients. The clinical photometric stereo endoscopy system consists of a commercial gastroscope, a commercial video processor, an image capturing and processing unit, custom synchronization electronics, white light LEDs, a set of four fibers with diffusing tips, and an alignment cap. The custom pieces that come into contact with the patient are composed of biocompatible materials that can be sterilized before use. The components can then be assembled in the endoscopy suite before use. The resulting endoscope has the same outer diameter as a conventional colonoscope (14 mm), plugs into a commercial video processor, captures topography and color images at 15 Hz, and displays the conventional color image to the gastroenterologist in real-time. We show that this system can capture a color and topographical video in a tubular colon phantom, demonstrating robustness to complex geometries and motion. The reported system is suitable for in vivo evaluation of photometric stereo endoscopy in the human large intestine.

  3. Improving Visibility of Stereo-Radiographic Spine Reconstruction with Geometric Inferences.

    Science.gov (United States)

    Kumar, Sampath; Nayak, K Prabhakar; Hareesha, K S

    2016-04-01

    Complex deformities of the spine, like scoliosis, are evaluated more precisely using stereo-radiographic 3D reconstruction techniques. Primarily, it uses six stereo-corresponding points available on the vertebral body for the 3D reconstruction of each vertebra. The wireframe structure obtained in this process has poor visualization, hence difficult to diagnose. In this paper, a novel method is proposed to improve the visibility of this wireframe structure using a deformation of a generic spine model in accordance with the 3D-reconstructed corresponding points. Then, the geometric inferences like vertebral orientations are automatically extracted from the radiographs to improve the visibility of the 3D model. Biplanar radiographs are acquired from five scoliotic subjects on a specifically designed calibration bench. The stereo-corresponding point reconstruction method is used to build six-point wireframe vertebral structures and thus the entire spine model. Using the 3D spine midline and automatically extracted vertebral orientation features, a more realistic 3D spine model is generated. To validate the method, the 3D spine model is back-projected on biplanar radiographs and the error difference is computed. Though, this difference is within the error limits available in the literature, the proposed work is simple and economical. The proposed method does not require more corresponding points and image features to improve the visibility of the model. Hence, it reduces the computational complexity. Expensive 3D digitizer and vertebral CT scan models are also excluded from this study. Thus, the visibility of stereo-corresponding point reconstruction is improved to obtain a low-cost spine model for a better diagnosis of spinal deformities.

  4. IMPACT: Science Goals and Firsts with STEREO

    Science.gov (United States)

    Luhmann, J.; Curtis, D.; Impact Team

    STEREO's IMPACT (In-situ Measurements of Particles and CME Transients) investigation provides the first opportunity for long duration, detailed observations of 1 AU magnetic field structures, plasma and suprathermal electrons, and energetic particles at points bracketing Earth's heliospheric location. The PLASTIC instrument, described in a companion presentation, will make plasma ion composition measurements completing STEREO's comprehensive in-situ perspective. Stereoscopic/3D information from the STEREO SECCHI imagers and SWAVES radio experiment, also described in this session, will make it possible to use both multipoint and quadrature studies to connect interplanetary Coronal Mass Ejections (ICME) and solar wind structures to CMEs and coronal holes observed at the Sun. IMPACT is also expected to test the patterns of solar energetic particle (SEP) events inferred from earlier statistical studies and multipoint measurements, and to resolve outstanding questions of source location(s) and seed populations with combinations of SEP composition measurements and other IMPACT and STEREO observations. Additional important insight will result from ongoing L1 viewpoint imaging and in-situ measurements from SOHO, WIND and ACE. In the late 1970s and early 1980s the Helios twin spacecraft mission obtained paired plasma, field and SEP in-situ data sets complemented by the Solwind and Solar Maximum Mission (SMM) coronagraph images of CMEs, and near-Earth in-situ data from IMP-8 and ISEE-3. IMPACT's updated instruments and modern data processing, transmitting, and analysis capabilities, with support from the other STEREO investigations and today's realistic 3D models of the corona, solar wind and CMEs, will prove or in some cases revolutionize the observational paradigms gleaned in the era of the Helios/Solwind/SMM/IMP-8/ISEE3 spacecraft combinations. The resulting views of in-situ space weather will without doubt leave us with a forever transformed perspective of L1

  5. Stereo-particle image velocimetry uncertainty quantification

    Science.gov (United States)

    Bhattacharya, Sayantan; Charonko, John J.; Vlachos, Pavlos P.

    2017-01-01

    Particle image velocimetry (PIV) measurements are subject to multiple elemental error sources and thus estimating overall measurement uncertainty is challenging. Recent advances have led to a posteriori uncertainty estimation methods for planar two-component PIV. However, no complete methodology exists for uncertainty quantification in stereo PIV. In the current work, a comprehensive framework is presented to quantify the uncertainty stemming from stereo registration error and combine it with the underlying planar velocity uncertainties. The disparity in particle locations of the dewarped images is used to estimate the positional uncertainty of the world coordinate system, which is then propagated to the uncertainty in the calibration mapping function coefficients. Next, the calibration uncertainty is combined with the planar uncertainty fields of the individual cameras through an uncertainty propagation equation and uncertainty estimates are obtained for all three velocity components. The methodology was tested with synthetic stereo PIV data for different light sheet thicknesses, with and without registration error, and also validated with an experimental vortex ring case from 2014 PIV challenge. Thorough sensitivity analysis was performed to assess the relative impact of the various parameters to the overall uncertainty. The results suggest that in absence of any disparity, the stereo PIV uncertainty prediction method is more sensitive to the planar uncertainty estimates than to the angle uncertainty, although the latter is not negligible for non-zero disparity. Overall the presented uncertainty quantification framework showed excellent agreement between the error and uncertainty RMS values for both the synthetic and the experimental data and demonstrated reliable uncertainty prediction coverage. This stereo PIV uncertainty quantification framework provides the first comprehensive treatment on the subject and potentially lays foundations applicable to volumetric

  6. McKay correspondence

    CERN Document Server

    Reid, M

    1997-01-01

    This is a rough write-up of my lecture at Kinosaki and two lectures at RIMS workshops in Dec 1996, on work in progress that has not yet reached any really worthwhile conclusion, but contains lots of fun calculations. History of Vafa's formula, how the McKay correspondence for finite subgroups of SL(n,C) relates to mirror symmetry. The main aim is to give numerical examples of how the 2 McKay correspondences (1) conjugacy classes of G homology of resolution (2) representations of G cohomology must work, and to restate my 1992 Conjecture as a *tautology*, like cohomology or K-theory of projective space. Another aim is to give an introduction to Nakamura's results on the Hilbert scheme of G-clusters, following his preprints and his many helpful explanations. This is partly based on joint work with Y. Ito, and has benefited from encouragement and invaluable suggestions of S. Mukai.

  7. English Business Correspondence

    Institute of Scientific and Technical Information of China (English)

    柯仁爱

    2014-01-01

    Against the background of economic globalization and regional integration, nations with their respective competitive advantages and disadvantages are becoming increasingly interdependent. Any country should learn how to utilize foreign resources as a source of its raw materials, a market of its finished products and an opportunity of obtaining the most advanced technology to improve its own comprehensive national strength. China has undergone more than twenty years’ reform and opening to the outside world, with China’s entry into WTO,international economic and technological cooperation and exchanges become more and more popular in China. People in business, whatever their titles are,spend a lot of time exchanging information with their foreign counterparts.Whenever there is an exchange, misunderstanding which is costly to business is likely to occur. However, appropriate business correspondence is given high evaluation and facilitates the achievement of business transaction. The competence of communicating effectively in business correspondence may bring great benefit for both the individuals and organizations.

  8. A correspondence principle

    Science.gov (United States)

    Hughes, Barry D.; Ninham, Barry W.

    2016-02-01

    A single mathematical theme underpins disparate physical phenomena in classical, quantum and statistical mechanical contexts. This mathematical "correspondence principle", a kind of wave-particle duality with glorious realizations in classical and modern mathematical analysis, embodies fundamental geometrical and physical order, and yet in some sense sits on the edge of chaos. Illustrative cases discussed are drawn from classical and anomalous diffusion, quantum mechanics of single particles and ideal gases, quasicrystals and Casimir forces.

  9. A spiking neural network model of 3D perception for event-based neuromorphic stereo vision systems

    Science.gov (United States)

    Osswald, Marc; Ieng, Sio-Hoi; Benosman, Ryad; Indiveri, Giacomo

    2017-01-01

    Stereo vision is an important feature that enables machine vision systems to perceive their environment in 3D. While machine vision has spawned a variety of software algorithms to solve the stereo-correspondence problem, their implementation and integration in small, fast, and efficient hardware vision systems remains a difficult challenge. Recent advances made in neuromorphic engineering offer a possible solution to this problem, with the use of a new class of event-based vision sensors and neural processing devices inspired by the organizing principles of the brain. Here we propose a radically novel model that solves the stereo-correspondence problem with a spiking neural network that can be directly implemented with massively parallel, compact, low-latency and low-power neuromorphic engineering devices. We validate the model with experimental results, highlighting features that are in agreement with both computational neuroscience stereo vision theories and experimental findings. We demonstrate its features with a prototype neuromorphic hardware system and provide testable predictions on the role of spike-based representations and temporal dynamics in biological stereo vision processing systems. PMID:28079187

  10. A spiking neural network model of 3D perception for event-based neuromorphic stereo vision systems

    Science.gov (United States)

    Osswald, Marc; Ieng, Sio-Hoi; Benosman, Ryad; Indiveri, Giacomo

    2017-01-01

    Stereo vision is an important feature that enables machine vision systems to perceive their environment in 3D. While machine vision has spawned a variety of software algorithms to solve the stereo-correspondence problem, their implementation and integration in small, fast, and efficient hardware vision systems remains a difficult challenge. Recent advances made in neuromorphic engineering offer a possible solution to this problem, with the use of a new class of event-based vision sensors and neural processing devices inspired by the organizing principles of the brain. Here we propose a radically novel model that solves the stereo-correspondence problem with a spiking neural network that can be directly implemented with massively parallel, compact, low-latency and low-power neuromorphic engineering devices. We validate the model with experimental results, highlighting features that are in agreement with both computational neuroscience stereo vision theories and experimental findings. We demonstrate its features with a prototype neuromorphic hardware system and provide testable predictions on the role of spike-based representations and temporal dynamics in biological stereo vision processing systems.

  11. Perceptual coding of stereo endoscopy video for minimally invasive surgery

    Science.gov (United States)

    Bartoli, Guido; Menegaz, Gloria; Yang, Guang Zhong

    2007-03-01

    In this paper, we propose a compression scheme that is tailored for stereo-laparoscope sequences. The inter-frame correlation is modeled by the deformation field obtained by elastic registration between two subsequent frames and exploited for prediction of the left sequence. The right sequence is lossy encoded by prediction from the corresponding left images. Wavelet-based coding is applied to both the deformation vector fields and residual images. The resulting system supports spatio temporal scalability, while providing lossless performance. The implementation of the wavelet transform by integer lifting ensures a low computational complexity, thus reducing the required run-time memory allocation and on line implementation. Extensive psychovisual tests were performed for system validation and characterization with respect to the MPEG4 standard for video coding. Results are very encouraging: the PSVC system features the functionalities making it suitable for PACS while providing a good trade-off between usability and performance in lossy mode.

  12. Modelling dense relational data

    DEFF Research Database (Denmark)

    Herlau, Tue; Mørup, Morten; Schmidt, Mikkel Nørgaard;

    2012-01-01

    Relational modelling classically consider sparse and discrete data. Measures of influence computed pairwise between temporal sources naturally give rise to dense continuous-valued matrices, for instance p-values from Granger causality. Due to asymmetry or lack of positive definiteness they are no......Relational modelling classically consider sparse and discrete data. Measures of influence computed pairwise between temporal sources naturally give rise to dense continuous-valued matrices, for instance p-values from Granger causality. Due to asymmetry or lack of positive definiteness...... they are not naturally suited for kernel K-means. We propose a generative Bayesian model for dense matrices which generalize kernel K-means to consider off-diagonal interactions in matrices of interactions, and demonstrate its ability to detect structure on both artificial data and two real data sets....

  13. Automatic Detection of Building Points from LIDAR and Dense Image Matching Point Clouds

    Science.gov (United States)

    Maltezos, E.; Ioannidis, C.

    2015-08-01

    This study aims to detect automatically building points: (a) from LIDAR point cloud using simple techniques of filtering that enhance the geometric properties of each point, and (b) from a point cloud which is extracted applying dense image matching at high resolution colour-infrared (CIR) digital aerial imagery using the stereo method semi-global matching (SGM). At first step, the removal of the vegetation is carried out. At the LIDAR point cloud, two different methods are implemented and evaluated using initially the normals and the roughness values afterwards: (1) the proposed scan line smooth filtering and a thresholding process, and (2) a bilateral filtering and a thresholding process. For the case of the CIR point cloud, a variation of the normalized differential vegetation index (NDVI) is computed for the same purpose. Afterwards, the bare-earth is extracted using a morphological operator and removed from the rest scene so as to maintain the buildings points. The results of the extracted buildings applying each approach at an urban area in northern Greece are evaluated using an existing orthoimage as reference; also, the results are compared with the corresponding classified buildings extracted from two commercial software. Finally, in order to verify the utility and functionality of the extracted buildings points that achieved the best accuracy, the 3D models in terms of Level of Detail 1 (LoD 1) and a 3D building change detection process are indicatively performed on a sub-region of the overall scene.

  14. Hierarchical adaptive stereo matching algorithm for obstacle detection with dynamic programming

    Institute of Scientific and Technical Information of China (English)

    Ming BAI; Yan ZHUANG; Wei WANG

    2009-01-01

    An adaptive weighted stereo matching algorithm with multilevel and bidirectional dynamic programming based on ground control points(GCPs) is presented.To decrease time complexity without losing matching precision,using a multilevel search scheme,the coarse matching is processed in typical disparity space image,while the fine matching is processed in disparity-offset space image.In the upper level,GCPs are obtained by enhanced volumetric iterative algorithm enforcing the mutual constraint and the threshold constraint.Under the supervision of the highly reliable GCPs,bidirec-tional dynamic programming framework is employed to solve the inconsistency in the optimization path.In the lower level,to reduce running time,disparity-offset space is proposed to efficiently achieve the dense disparity image.In addition,an adaptive dual support-weight strategy is presented to aggregate matching cost,which considers photometric and geomet-ric information.Further,post-processing algorithm can ameliorate disparity results in areas with depth discontinuities and related by occlusions using dual threshold algorithm,where missing stereo information is substituted from surrounding re-gions.To demonstrate the effectiveness of the algorithm,we present the two groups of experimental results for four widely used standard stereo data sets,including discussion on performance and comparison with other methods,which show that the algorithm has not only a fast speed,but also significantly improves the efficiency of holistic optimization.

  15. Accuracy Evaluation of Stereo Vision Aided Inertial Navigation for Indoor Environments

    Science.gov (United States)

    Griessbach, D. G.; Baumbach, D. B.; Boerner, A. B.; Zuev, S. Z.

    2013-11-01

    Accurate knowledge of position and orientation is a prerequisite for many applications regarding unmanned navigation, mapping, or environmental modelling. GPS-aided inertial navigation is the preferred solution for outdoor applications. Nevertheless a similar solution for navigation tasks in difficult environments with erroneous or no GPS-data is needed. Therefore a stereo vision aided inertial navigation system is presented which is capable of providing real-time local navigation for indoor applications. A method is described to reconstruct the ego motion of a stereo camera system aided by inertial data. This, in turn, is used to constrain the inertial sensor drift. The optical information is derived from natural landmarks, extracted and tracked over consequent stereo image pairs. Using inertial data for feature tracking effectively reduces computational costs and at the same time increases the reliability due to constrained search areas. Mismatched features, e.g. at repetitive structures typical for indoor environments are avoided. An Integrated Positioning System (IPS) was deployed and tested on an indoor navigation task. IPS was evaluated for accuracy, robustness, and repeatability in a common office environment. In combination with a dense disparity map, derived from the navigation cameras, a high density point cloud is generated to show the capability of the navigation algorithm.

  16. Incorporating polarization in stereo vision-based 3D perception of non-Lambertian scenes

    Science.gov (United States)

    Berger, Kai; Voorhies, Randolph; Matthies, Larry

    2016-05-01

    Surfaces with specular, non-Lambertian reflectance are common in urban areas. Robot perception systems for applications in urban environments need to function effectively in the presence of such materials; however, both passive and active 3-D perception systems have difficulties with them. In this paper, we develop an approach using a stereo pair of polarization cameras to improve passive 3-D perception of specular surfaces. We use a commercial stereo camera pair with rotatable polarization filters in front of each lens to capture images with multiple orientations of the polarization filter. From these images, we estimate the degree of linear polarization (DOLP) and the angle of polarization (AOP) at each pixel in at least one camera. The AOP constrains the corresponding surface normal in the scene to lie in the plane of the observed angle of polarization. We embody this constraint an energy functional for a regularization-based stereo vision algorithm. This paper describes the theory of polarization needed for this approach, describes the new stereo vision algorithm, and presents results on synthetic and real images to evaluate performance.

  17. Multi-hypothesis distributed stereo video coding

    DEFF Research Database (Denmark)

    Salmistraro, Matteo; Zamarin, Marco; Forchhammer, Søren

    2013-01-01

    Distributed Video Coding (DVC) is a video coding paradigm that exploits the source statistics at the decoder based on the availability of the Side Information (SI). Stereo sequences are constituted by two views to give the user an illusion of depth. In this paper, we present a DVC decoder...... for stereo sequences, exploiting an interpolated intra-view SI and two inter-view SIs. The quality of the SI has a major impact on the DVC Rate-Distortion (RD) performance. As the inter-view SIs individually present lower RD performance compared with the intra-view SI, we propose multi-hypothesis decoding...... for robust fusion and improved performance. Compared with a state-of-the-art single side information solution, the proposed DVC decoder improves the RD performance for all the chosen test sequences by up to 0.8 dB. The proposed multi-hypothesis decoder showed higher robustness compared with other fusion...

  18. Acceleration of Stereo Correlation in Verilog

    Science.gov (United States)

    Villalpando, Carlos

    2006-01-01

    To speed up vision processing in low speed, low power devices, embedding FPGA hardware is becoming an effective way to add processing capability. FPGAs offer the ability to flexibly add parallel and/or deeply pipelined computation to embedded processors without adding significantly to the mass and power requirements of an embedded system. This paper will discuss the JPL stereo vision system, and describe how a portion of that system was accelerated by using custom FPGA hardware to process the computationally intensive portions of JPL stereo. The architecture described takes full advantage of the ability of an FPGA to use many small computation elements in parallel. This resulted in a 16 times speedup in real hardware over using a simple linear processor to compute image correlation and disparity.

  19. Unwrapping and stereo rectification for omnidirectional images

    Institute of Scientific and Technical Information of China (English)

    Jie LEI; Xin DU; Yun-fang ZHU; Ji-lin LIU

    2009-01-01

    Omnidirectional imaging sensors have been used in more and more applications when a very large field of view is required. In this paper, we investigate the unwrapping, epipolar geometry and stereo rectification issues for omnidirectional vision when the particular mirror model and the camera parameters are unknown in priori. First, the omnidirectional camera is calibrated under the Taylor model, and the parameters related to this model are obtained. In order to make the classical computer vision algorithms of conventional perspective cameras applicable, the ring omnidirectional image is unwrapped into two kinds of panoramas: cylinder and cuboid. Then the epipolar geometry of arbitrary camera configuration is analyzed and the essential matrix is deduced with its properties being indicated for ring images. After that, a simple stereo rectification method based on the essential matrix and the conformal mapping is proposed. Simulations and real data experimental results illustrate that our methods are effective for the omnidirectional camera under the constraint of a single view point.

  20. Viscoelastic behavior of dense microemulsions

    Science.gov (United States)

    Cametti, C.; Codastefano, P.; D'arrigo, G.; Tartaglia, P.; Rouch, J.; Chen, S. H.

    1990-09-01

    We have performed extensive measurements of shear viscosity, ultrasonic absorption, and sound velocity in a ternary system consisting of water-decane-sodium di(2-ethylhexyl)sulfo- succinate(AOT), in the one-phase region where it forms a water-in-oil microemulsion. We observe a rapid increase of the static shear viscosity in the dense microemulsion region. Correspondingly the sound absorption shows unambiguous evidence of a viscoelastic behavior. The absorption data for various volume fractions and temperatures can be reduced to a universal curve by scaling both the absorption and the frequency by the measured static shear viscosity. The sound absorption can be interpreted as coming from the high-frequency tail of the viscoelastic relaxation, describable by a Cole-Cole relaxation formula with unusually small elastic moduli.

  1. Building a dense surface map incrementally from semi-dense point cloud and RGB images

    Institute of Scientific and Technical Information of China (English)

    Qian-shan LI; Rong XIONG; Shoudong HUANG; Yi-ming HUANG

    2015-01-01

    Building and using maps is a fundamental issue for bionic robots in fi eld applications. A dense surface map, which offers rich visual and geometric information, is an ideal representation of the environment for indoor/outdoor localization, navigation, and recognition tasks of these robots. Since most bionic robots can use only small light-weight laser scanners and cameras to acquire semi-dense point cloud and RGB images, we propose a method to generate a consistent and dense surface map from this kind of semi-dense point cloud and RGB images. The method contains two main steps: (1) generate a dense surface for every single scan of point cloud and its corresponding image(s) and (2) incrementally fuse the dense surface of a new scan into the whole map. In step (1) edge-aware resampling is realized by segmenting the scan of a point cloud in advance and resampling each sub-cloud separately. Noise within the scan is reduced and a dense surface is generated. In step (2) the average surface is estimated probabilistically and the non-coincidence of different scans is eliminated. Experiments demonstrate that our method works well in both indoor and outdoor semi-structured environments where there are regularly shaped ob jects.

  2. The analogy between stereo depth and brightness.

    Science.gov (United States)

    Brookes, A; Stevens, K A

    1989-01-01

    Apparent depth in stereograms exhibits various simultaneous-contrast and induction effects analogous to those reported in the luminance domain. This behavior suggests that stereo depth, like brightness, is reconstructed, ie recovered from higher-order spatial derivatives or differences of the original signal. The extent to which depth is analogous to brightness is examined. There are similarities in terms of contrast effects but dissimilarities in terms of the lateral inhibition effects traditionally attributed to underlying spatial-differentiation operators.

  3. Stereo cameras on the International Space Station

    Science.gov (United States)

    Sabbatini, Massimo; Visentin, Gianfranco; Collon, Max; Ranebo, Hans; Sunderland, David; Fortezza, Raimondo

    2007-02-01

    Three-dimensional media is a unique and efficient means to virtually visit/observe objects that cannot be easily reached otherwise, like the International Space Station. The advent of auto-stereoscopic displays and stereo projection system is making the stereo media available to larger audiences than the traditional scientists and design engineers communities. It is foreseen that a major demand for 3D content shall come from the entertainment area. Taking advantage of the 6 months long permanence on the International Space Station of a colleague European Astronaut, Thomas Reiter, the Erasmus Centre uploaded to the ISS a newly developed, fully digital stereo camera, the Erasmus Recording Binocular. Testing the camera and its human interfaces in weightlessness, as well as accurately mapping the interior of the ISS are the main objectives of the experiment that has just been completed at the time of writing. The intent of this paper is to share with the readers the design challenges tackled in the development and operation of the ERB camera and highlight some of the future plans the Erasmus Centre team has in the pipeline.

  4. Two new macro-stereo cameras for medical photography with special reference to the eye.

    Science.gov (United States)

    AandeKerk, A L

    1991-04-01

    Information is given on two new macro-stereo cameras for simultaneous stereo photography designed by members of the Dutch Stereo Society. These cameras can be used for medical photography. The first camera takes half frame stereo pictures and utilizes frames for positioning and focusing. The second camera takes full frame stereo pictures and utilizes spots projection for positioning and focusing. Examples are shown.

  5. Characteristics of EUV Coronal Jets Observed with STEREO/SECCHI

    Science.gov (United States)

    Nisticò, G.; Bothmer, V.; Patsourakos, S.; Zimbardo, G.

    2009-10-01

    In this paper we present the first comprehensive statistical study of EUV coronal jets observed with the SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) imaging suites of the two STEREO spacecraft. A catalogue of 79 polar jets is presented, identified from simultaneous EUV and white-light coronagraph observations, taken during the time period March 2007 to April 2008, when solar activity was at a minimum. The twin spacecraft angular separation increased during this time interval from 2 to 48 degrees. The appearances of the coronal jets were always correlated with underlying small-scale chromospheric bright points. A basic characterization of the morphology and identification of the presence of helical structure were established with respect to recently proposed models for their origin and temporal evolution. Though each jet appeared morphologically similar in the coronagraph field of view, in the sense of a narrow collimated outward flow of matter, at the source region in the low corona the jet showed different characteristics, which may correspond to different magnetic structures. A classification of the events with respect to previous jet studies shows that amongst the 79 events there were 37 Eiffel tower-type jet events, commonly interpreted as a small-scale (˜35 arc sec) magnetic bipole reconnecting with the ambient unipolar open coronal magnetic fields at its loop tops, and 12 lambda-type jet events commonly interpreted as reconnection with the ambient field happening at the bipole footpoints. Five events were termed micro-CME-type jet events because they resembled the classical coronal mass ejections (CMEs) but on much smaller scales. The remaining 25 cases could not be uniquely classified. Thirty-one of the total number of events exhibited a helical magnetic field structure, indicative for a torsional motion of the jet around its axis of propagation. A few jets are also found in equatorial coronal holes. In this study we present sample

  6. Vhrs Stereo Images for 3d Modelling of Buildings

    Science.gov (United States)

    Bujakiewicz, A.; Holc, M.

    2012-07-01

    The paper presents the project which was carried out in the Photogrammetric Laboratory of Warsaw University of Technology. The experiment is concerned with the extraction of 3D vector data for buildings creation from 3D photogrammetric model based on the Ikonos stereo images. The model was reconstructed with photogrammetric workstation - Summit Evolution combined with ArcGIS 3D platform. Accuracy of 3D model was significantly improved by use for orientation of pair of satellite images the stereo measured tie points distributed uniformly around the model area in addition to 5 control points. The RMS for model reconstructed on base of the RPC coefficients only were 16,6 m, 2,7 m and 47,4 m, for X, Y and Z coordinates, respectively. By addition of 5 control points the RMS were improved to 0,7 m, 0,7 m 1,0 m, where the best results were achieved when RMS were estimated from deviations in 17 check points (with 5 control points)and amounted to 0,4 m, 0,5 m and 0,6 m, for X, Y, and Z respectively. The extracted 3D vector data for buildings were integrated with 2D data of the ground footprints and afterwards they were used for 3D modelling of buildings in Google SketchUp software. The final results were compared with the reference data obtained from other sources. It was found that the shape of buildings (in concern to the number of details) had been reconstructed on level of LoD1, when the accuracy of these models corresponded to the level of LoD2.

  7. VHRS STEREO IMAGES FOR 3D MODELLING OF BUILDINGS

    Directory of Open Access Journals (Sweden)

    A. Bujakiewicz

    2012-07-01

    Full Text Available The paper presents the project which was carried out in the Photogrammetric Laboratory of Warsaw University of Technology. The experiment is concerned with the extraction of 3D vector data for buildings creation from 3D photogrammetric model based on the Ikonos stereo images. The model was reconstructed with photogrammetric workstation – Summit Evolution combined with ArcGIS 3D platform. Accuracy of 3D model was significantly improved by use for orientation of pair of satellite images the stereo measured tie points distributed uniformly around the model area in addition to 5 control points. The RMS for model reconstructed on base of the RPC coefficients only were 16,6 m, 2,7 m and 47,4 m, for X, Y and Z coordinates, respectively. By addition of 5 control points the RMS were improved to 0,7 m, 0,7 m 1,0 m, where the best results were achieved when RMS were estimated from deviations in 17 check points (with 5 control pointsand amounted to 0,4 m, 0,5 m and 0,6 m, for X, Y, and Z respectively. The extracted 3D vector data for buildings were integrated with 2D data of the ground footprints and afterwards they were used for 3D modelling of buildings in Google SketchUp software. The final results were compared with the reference data obtained from other sources. It was found that the shape of buildings (in concern to the number of details had been reconstructed on level of LoD1, when the accuracy of these models corresponded to the level of LoD2.

  8. Robust surface reconstruction by design-guided SEM photometric stereo

    Science.gov (United States)

    Miyamoto, Atsushi; Matsuse, Hiroki; Koutaki, Gou

    2017-04-01

    We present a novel approach that addresses the blind reconstruction problem in scanning electron microscope (SEM) photometric stereo for complicated semiconductor patterns to be measured. In our previous work, we developed a bootstrapping de-shadowing and self-calibration (BDS) method, which automatically calibrates the parameter of the gradient measurement formulas and resolves shadowing errors for estimating an accurate three-dimensional (3D) shape and underlying shadowless images. Experimental results on 3D surface reconstruction demonstrated the significance of the BDS method for simple shapes, such as an isolated line pattern. However, we found that complicated shapes, such as line-and-space (L&S) and multilayered patterns, produce deformed and inaccurate measurement results. This problem is due to brightness fluctuations in the SEM images, which are mainly caused by the energy fluctuations of the primary electron beam, variations in the electronic expanse inside a specimen, and electrical charging of specimens. Despite these being essential difficulties encountered in SEM photometric stereo, it is difficult to model accurately all the complicated physical phenomena of electronic behavior. We improved the robustness of the surface reconstruction in order to deal with these practical difficulties with complicated shapes. Here, design data are useful clues as to the pattern layout and layer information of integrated semiconductors. We used the design data as a guide of the measured shape and incorporated a geometrical constraint term to evaluate the difference between the measured and designed shapes into the objective function of the BDS method. Because the true shape does not necessarily correspond to the designed one, we use an iterative scheme to develop proper guide patterns and a 3D surface that provides both a less distorted and more accurate 3D shape after convergence. Extensive experiments on real image data demonstrate the robustness and effectiveness

  9. Lossless Compression of Stereo Disparity Maps for 3D

    DEFF Research Database (Denmark)

    Zamarin, Marco; Forchhammer, Søren

    2012-01-01

    Efficient compression of disparity data is important for accurate view synthesis purposes in multi-view communication systems based on the “texture plus depth” format, including the stereo case. In this paper a novel technique for lossless compression of stereo disparity images is presented...... disparity maps for stereo pairs and outperforms different standard solutions for lossless still image compression. Moreover, it provides a progressive representation of disparity data as well as a parallelizable structure....

  10. Dense Plasma Focus Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hui [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Li, Shengtai [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jungman, Gerard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hayes-Sterbenz, Anna Catherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-31

    The mechanisms for pinch formation in Dense Plasma Focus (DPF) devices, with the generation of high-energy ions beams and subsequent neutron production over a relatively short distance, are not fully understood. Here we report on high-fidelity 2D and 3D numerical magnetohydrodynamic (MHD) simulations using the LA-COMPASS code to study the pinch formation dynamics and its associated instabilities and neutron production.

  11. Calibration of a Stereo Radiation Detection Camera Using Planar Homography

    Directory of Open Access Journals (Sweden)

    Seung-Hae Baek

    2016-01-01

    Full Text Available This paper proposes a calibration technique of a stereo gamma detection camera. Calibration of the internal and external parameters of a stereo vision camera is a well-known research problem in the computer vision society. However, few or no stereo calibration has been investigated in the radiation measurement research. Since no visual information can be obtained from a stereo radiation camera, it is impossible to use a general stereo calibration algorithm directly. In this paper, we develop a hybrid-type stereo system which is equipped with both radiation and vision cameras. To calibrate the stereo radiation cameras, stereo images of a calibration pattern captured from the vision cameras are transformed in the view of the radiation cameras. The homography transformation is calibrated based on the geometric relationship between visual and radiation camera coordinates. The accuracy of the stereo parameters of the radiation camera is analyzed by distance measurements to both visual light and gamma sources. The experimental results show that the measurement error is about 3%.

  12. Converting conventional stereo pairs to multiview sequences using morphing

    Science.gov (United States)

    Olsson, Roger; Adhikarla, Vamsi Kiran; Schwarz, Sebastian; Sjöström, Mårten

    2012-03-01

    Autostereoscopic multi view displays require multiple views of a scene to provide motion parallax. When an observer changes viewing angle different stereoscopic pairs are perceived. This allows new perspectives of the scene to be seen giving a more realistic 3D experience. However, capturing arbitrary number of views is at best cumbersome, and in some occasions impossible. Conventional stereo video (CSV) operates on two video signals captured using two cameras at two different perspectives. Generation and transmission of two views is more feasible than that of multiple views. It would be more efficient if multiple views required by an autostereoscopic display can be synthesized from these sparse set of views. This paper addresses the conversion of stereoscopic video to multiview video using the video effect morphing. Different morphing algorithms are implemented and evaluated. Contrary to traditional conversion methods, these algorithms disregard the physical depth explicitly and instead generate intermediate views using sparse sets of correspondence features and image morphing. A novel morphing algorithm is also presented that uses scale invariant feature transform (SIFT) and segmentation to construct robust correspondences features and qualitative intermediate views. All algorithms are evaluated on a subjective and objective basis and the comparison results are presented.

  13. Trinocular stereo vision method based on mesh candidates

    Science.gov (United States)

    Liu, Bin; Xu, Gang; Li, Haibin

    2010-10-01

    One of the most interesting goals of machine vision is 3D structure recovery of the scenes. This recovery has many applications, such as object recognition, reverse engineering, automatic cartography, autonomous robot navigation, etc. To meet the demand of measuring the complex prototypes in reverse engineering, a trinocular stereo vision method based on mesh candidates was proposed. After calibration of the cameras, the joint field of view can be defined in the world coordinate system. Mesh grid is established along the coordinate axes, and the mesh nodes are considered as potential depth data of the object surface. By similarity measure of the correspondence pairs which are projected from a certain group of candidates, the depth data can be obtained readily. With mesh nodes optimization, the interval between the neighboring nodes in depth direction could be designed reasonably. The potential ambiguity can be eliminated efficiently in correspondence matching with the constraint of a third camera. The cameras can be treated as two independent pairs, left-right and left-centre. Due to multiple peaks of the correlation values, the binocular method may not satisfy the accuracy of the measurement. Another image pair is involved if the confidence coefficient is less than the preset threshold. The depth is determined by the highest sum of correlation of both camera pairs. The measurement system was simulated using 3DS MAX and Matlab software for reconstructing the surface of the object. The experimental result proved that the trinocular vision system has good performance in depth measurement.

  14. Solar Eclipse Video Captured by STEREO-B

    Science.gov (United States)

    2007-01-01

    No human has ever witnessed a solar eclipse quite like the one captured on this video. The NASA STEREO-B spacecraft, managed by the Goddard Space Center, was about a million miles from Earth , February 25, 2007, when it photographed the Moon passing in front of the sun. The resulting movie looks like it came from an alien solar system. The fantastically-colored star is our own sun as STEREO sees it in four wavelengths of extreme ultraviolet light. The black disk is the Moon. When we observe a lunar transit from Earth, the Moon appears to be the same size as the sun, a coincidence that produces intoxicatingly beautiful solar eclipses. The silhouette STEREO-B saw, on the other hand, was only a fraction of the Sun. The Moon seems small because of the STEREO-B location. The spacecraft circles the sun in an Earth-like orbit, but it lags behind Earth by one million miles. This means STEREO-B is 4.4 times further from the Moon than we are, and so the Moon looks 4.4 times smaller. This version of the STEREO-B eclipse movie is a composite of data from the coronagraph and extreme ultraviolet imager of the spacecraft. STEREO-B has a sister ship named STEREO-A. Both are on a mission to study the sun. While STEREO-B lags behind Earth, STEREO-A orbits one million miles ahead ('B' for behind, 'A' for ahead). The gap is deliberate as it allows the two spacecraft to capture offset views of the sun. Researchers can then combine the images to produce 3D stereo movies of solar storms. The two spacecraft were launched in Oct. 2006 and reached their stations on either side of Earth in January 2007.

  15. Stereo morphology of temporal bone and ear

    Institute of Scientific and Technical Information of China (English)

    戴朴; 刘阳; 姜泗长; 方耀云; 王今; 杨伟炎

    2004-01-01

    Background The temporal bone has the most complicated anatomic feature among the whole human body, which always challenges otolaryngologists. This study was to study three-dimensional (3D) morphology of the temporal bone and the ear by means of a computer image processing technique, for the purpose of providing a 3D image to help in pathological, diagnostic and surgical procedures. Methods Forty sets of temporal bone celloidin serial sections with reference points were prepared and the contours of selected structures and reference points were entered into a graphics programme. The technique of computer-aided 3D reconstruction was applied to obtain 3D images and parameters of the temporal bones and the ears. Stereo views of the ossicles (n=5), the facial nerves (n=11), the posterior tympanic sinuses (n=11), the posterior ampullary nerves (n=4), the endolymphatic ducts and sacs (n=5), and the bony and membranous labyrinth (n=1) were reconstructed. Results Three-dimensional images, including the cochlea, the ossicles, the nerves, the tendons and the endolymphatic fluid system in the temporal bone, were obtained. Stereo picture pairs and 3D parameters of spatial dimensions, angle and volume for these reconstructed structures were calculated. The arrangement of the ossicles, spatial relationship of the bony and membranous labyrinth, the whole course of the facial nerves, the endolymphatic sac and posterior tympanic cavity were clearly observable. Stereo picture pairs made the spatial relationships among the above-mentioned structures much clearer. The operation of the posterior ampullary nerve transection was designed and simulated on the graphic computer based on 3D anatomic investigations. Conclusion The technique of computer-aided 3D reconstruction provides a new tool to observe the morphology of the temporal bone and thus may allow design and study of new surgical approaches.

  16. STEREO Superior Solar Conjunction Mission Phase

    Science.gov (United States)

    Ossing, Daniel A.; Wilson, Daniel; Balon, Kevin; Hunt, Jack; Dudley, Owen; Chiu, George; Coulter, Timothy; Reese, Angel; Cox, Matthew; Srinivasan, Dipak; hide

    2017-01-01

    With its long duration and high gain antenna (HGA) feed thermal constraint; the NASA Solar-TErestrial RElations Observatory (STEREO) solar conjunction mission phase is quite unique to deep space operations. Originally designed for a two year heliocentric orbit mission to primarily study coronal mass ejection propagation, after 8 years of continuous science data collection, the twin STEREO observatories entered the solar conjunction mission phase, for which they were not designed. Nine months before entering conjunction, an unforeseen thermal constraint threatened to stop daily communications and science data collection for 15months. With a 3.5 month long communication blackout from the superior solar conjunction, without ground commands, each observatory will reset every 3 days, resulting in 35 system resets at an Earth range of 2 AU. As the observatories will be conjoined for the first time in 8 years, a unique opportunity for calibrating the same instruments on identical spacecraft will occur. As each observatory has lost redundancy, and with only a limited fidelity hardware simulator, how can the new observatory configuration be adequately and safely tested on each spacecraft? Without ground commands, how would a 3-axis stabilized spacecraft safely manage the ever accumulating system momentum without using propellant for thrusters? Could science data still be collected for the duration of the solar conjunction mission phase? Would the observatories survive? In its second extended mission, operational resources were limited at best. This paper discusses the solutions to the STEREO superior solar conjunction operational challenges, science data impact, testing, mission operations, results, and lessons learned while implementing.

  17. Small Orbital Stereo Tracking Camera Technology Development

    Science.gov (United States)

    Bryan, Tom; MacLeod, Todd; Gagliano, Larry

    2016-01-01

    On-Orbit Small Debris Tracking and Characterization is a technical gap in the current National Space Situational Awareness necessary to safeguard orbital assets and crew. This poses a major risk of MOD damage to ISS and Exploration vehicles. In 2015 this technology was added to NASA's Office of Chief Technologist roadmap. For missions flying in or assembled in or staging from LEO, the physical threat to vehicle and crew is needed in order to properly design the proper level of MOD impact shielding and proper mission design restrictions. Need to verify debris flux and size population versus ground RADAR tracking. Use of ISS for In-Situ Orbital Debris Tracking development provides attitude, power, data and orbital access without a dedicated spacecraft or restricted operations on-board a host vehicle as a secondary payload. Sensor Applicable to in-situ measuring orbital debris in flux and population in other orbits or on other vehicles. Could enhance safety on and around ISS. Some technologies extensible to monitoring of extraterrestrial debris as well To help accomplish this, new technologies must be developed quickly. The Small Orbital Stereo Tracking Camera is one such up and coming technology. It consists of flying a pair of intensified megapixel telephoto cameras to evaluate Orbital Debris (OD) monitoring in proximity of International Space Station. It will demonstrate on-orbit optical tracking (in situ) of various sized objects versus ground RADAR tracking and small OD models. The cameras are based on Flight Proven Advanced Video Guidance Sensor pixel to spot algorithms (Orbital Express) and military targeting cameras. And by using twin cameras we can provide Stereo images for ranging & mission redundancy. When pointed into the orbital velocity vector (RAM), objects approaching or near the stereo camera set can be differentiated from the stars moving upward in background.

  18. Developing stereo image based robot control system

    Science.gov (United States)

    Suprijadi, Pambudi, I. R.; Woran, M.; Naa, C. F.; Srigutomo, W.

    2015-04-01

    Application of image processing is developed in various field and purposes. In the last decade, image based system increase rapidly with the increasing of hardware and microprocessor performance. Many fields of science and technology were used this methods especially in medicine and instrumentation. New technique on stereovision to give a 3-dimension image or movie is very interesting, but not many applications in control system. Stereo image has pixel disparity information that is not existed in single image. In this research, we proposed a new method in wheel robot control system using stereovision. The result shows robot automatically moves based on stereovision captures.

  19. Hyperspectral photometric stereo for a single capture.

    Science.gov (United States)

    Ozawa, Keisuke; Sato, Imari; Yamaguchi, Masahiro

    2017-03-01

    We present a single-capture photometric stereo method using a hyperspectral camera. A spectrally and spatially designed illumination enables a point-wise estimation of reflectance spectra and surface normals from a single hyperspectral image. The illumination works as a reflectance probe in wide spectral regions where reflectance spectra are measured, and the full spectra are estimated by interpolation. It also works as the resource for shadings in other spectral regions. The accuracy of estimation is evaluated in a simulation. Also, we prepare an experimental setup and demonstrate a surface reconstruction against a real scene.

  20. A Stereo Vision Visualization Method in Welding

    Science.gov (United States)

    Zhao, Chuangxin; Richardson, Ian M.; Kleijn, Chris; Kenjeres, Sasa; Saldi, Zaki

    2008-09-01

    The oscillation of weld pool surface, vaporization and spatters make the measurement in welding difficult; two dimensional results can not reflect enough information in welding. However, there are few direct three dimensional methods to understand the fluid flow during welding. In this paper, we described a three dimensional reconstruction method to measure velocity in welding based on a single high speed camera. A stereo adapter was added in front of the high speed camera lens to obtain two images in the same frame from different view points at the same time; according to the machine vision theory, three dimensional parameters could be reconstructed based on these two images

  1. Developing stereo image based robot control system

    Energy Technology Data Exchange (ETDEWEB)

    Suprijadi,; Pambudi, I. R.; Woran, M.; Naa, C. F; Srigutomo, W. [Department of Physics, FMIPA, InstitutTeknologi Bandung Jl. Ganesha No. 10. Bandung 40132, Indonesia supri@fi.itb.ac.id (Indonesia)

    2015-04-16

    Application of image processing is developed in various field and purposes. In the last decade, image based system increase rapidly with the increasing of hardware and microprocessor performance. Many fields of science and technology were used this methods especially in medicine and instrumentation. New technique on stereovision to give a 3-dimension image or movie is very interesting, but not many applications in control system. Stereo image has pixel disparity information that is not existed in single image. In this research, we proposed a new method in wheel robot control system using stereovision. The result shows robot automatically moves based on stereovision captures.

  2. Obstacle detection during day and night conditions using stereo vision

    NARCIS (Netherlands)

    Dubbelman, G.; Mark, W. van der; Heuvel, J.C. van den; Groen, F.C.A.

    2007-01-01

    We have developed a stereo vision based obstacle detection (OD) system that can be used to detect obstacles in off-road terrain during both day and night conditions. In order to acquire enough depth estimates for reliable OD during low visibility conditions, we propose a stereo disparity (depth) est

  3. A new benchmark for stereo-based pedestrian detection

    NARCIS (Netherlands)

    C.G. Keller; M. Enzweiler; D.M. Gavrila

    2011-01-01

    Pedestrian detection is a rapidly evolving area in the intelligent vehicles domain. Stereo vision is an attractive sensor for this purpose. But unlike for monocular vision, there are no realistic, large scale benchmarks available for stereo-based pedestrian detection, to provide a common point of re

  4. Object recognition with stereo vision and geometric hashing

    NARCIS (Netherlands)

    Dijck, van Harry; Heijden, van der Ferdinand

    2003-01-01

    In this paper we demonstrate a method to recognize 3D objects and to estimate their pose. For that purpose we use a combination of stereo vision and geometric hashing. Stereo vision is used to generate a large number of 3D low level features, of which many are spurious because at that stage of the p

  5. Object recognition with stereo vision and geometric hashing

    NARCIS (Netherlands)

    van Dijck, H.A.L.; van der Heijden, Ferdinand

    In this paper we demonstrate a method to recognize 3D objects and to estimate their pose. For that purpose we use a combination of stereo vision and geometric hashing. Stereo vision is used to generate a large number of 3D low level features, of which many are spurious because at that stage of the

  6. Owls see in stereo much like humans do

    NARCIS (Netherlands)

    Willigen, R.F. van der

    2011-01-01

    While 3D experiences through binocular disparity sensitivity have acquired special status in the understanding of human stereo vision, much remains to be learned about how binocularity is put to use in animals. The owl provides an exceptional model to study stereo vision as it displays one of the hi

  7. Warm dense crystallography

    Science.gov (United States)

    Valenza, Ryan A.; Seidler, Gerald T.

    2016-03-01

    The intense femtosecond-scale pulses from x-ray free electron lasers (XFELs) are able to create and interrogate interesting states of matter characterized by long-lived nonequilibrium semicore or core electron occupancies or by the heating of dense phases via the relaxation cascade initiated by the photoelectric effect. We address here the latter case of "warm dense matter" (WDM) and investigate the observable consequences of x-ray heating of the electronic degrees of freedom in crystalline systems. We report temperature-dependent density functional theory calculations for the x-ray diffraction from crystalline LiF, graphite, diamond, and Be. We find testable, strong signatures of condensed-phase effects that emphasize the importance of wide-angle scattering to study nonequilibrium states. These results also suggest that the reorganization of the valence electron density at eV-scale temperatures presents a confounding factor to achieving atomic resolution in macromolecular serial femtosecond crystallography (SFX) studies at XFELs, as performed under the "diffract before destroy" paradigm.

  8. Dense Suspension Splash

    Science.gov (United States)

    Zhang, Wendy; Dodge, Kevin M.; Peters, Ivo R.; Ellowitz, Jake; Klein Schaarsberg, Martin H.; Jaeger, Heinrich M.

    2014-03-01

    Upon impact onto a solid surface at several meters-per-second, a dense suspension plug splashes by ejecting liquid-coated particles. We study the mechanism for splash formation using experiments and a numerical model. In the model, the dense suspension is idealized as a collection of cohesionless, rigid grains with finite surface roughness. The grains also experience lubrication drag as they approach, collide inelastically and rebound away from each other. Simulations using this model reproduce the measured momentum distribution of ejected particles. They also provide direct evidence supporting the conclusion from earlier experiments that inelastic collisions, rather than viscous drag, dominate when the suspension contains macroscopic particles immersed in a low-viscosity solvent such as water. Finally, the simulations reveal two distinct routes for splash formation: a particle can be ejected by a single high momentum-change collision. More surprisingly, a succession of small momentum-change collisions can accumulate to eject a particle outwards. Supported by NSF through its MRSEC program (DMR-0820054) and fluid dynamics program (CBET-1336489).

  9. Dense Axion Stars

    CERN Document Server

    Braaten, Eric; Zhang, Hong

    2015-01-01

    If the dark matter consists of axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound Bose-Einstein condensates of axions. In the previously known axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure.If the axion mass energy is $mc^2= 10^{-4}$ eV, these dilute axion stars have a maximum mass of about $10^{-14} M_\\odot$. We point out that there are also dense axion stars in which gravity is balanced by the mean-field pressure of the axion condensate. We study axion stars using the leading term in a systematically improvable approximation to the effective potential of the nonrelativistic effective field theory for axions. Using the Thomas-Fermi approximation in which the kinetic pressure is neglected, we find a sequence of new branches of axion stars in which gravity is balanced by the mean-field interaction energy of the axion condensate. If $mc^2 = 10^{-4}$ eV, the first branch of these dense axion stars has mas...

  10. Dense Axion Stars

    Science.gov (United States)

    Braaten, Eric; Mohapatra, Abhishek; Zhang, Hong

    2016-09-01

    If the dark matter particles are axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound systems of axions. In the previously known solutions for axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. The mass of these dilute axion stars cannot exceed a critical mass, which is about 10-14M⊙ if the axion mass is 10-4 eV . We study axion stars using a simple approximation to the effective potential of the nonrelativistic effective field theory for axions. We find a new branch of dense axion stars in which gravity is balanced by the mean-field pressure of the axion Bose-Einstein condensate. The mass on this branch ranges from about 10-20M⊙ to about M⊙ . If a dilute axion star with the critical mass accretes additional axions and collapses, it could produce a bosenova, leaving a dense axion star as the remnant.

  11. Dense Axion Stars

    Science.gov (United States)

    Mohapatra, Abhishek; Braaten, Eric; Zhang, Hong

    2016-03-01

    If the dark matter consists of axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound Bose-Einstein condensates of axions. In the previously known axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. If the axion mass energy is mc2 =10-4 eV, these dilute axion stars have a maximum mass of about 10-14M⊙ . We point out that there are also dense axion stars in which gravity is balanced by the mean-field pressure of the axion condensate. We study axion stars using the leading term in a systematically improvable approximation to the effective potential of the nonrelativistic effective field theory for axions. Using the Thomas-Fermi approximation in which the kinetic pressure is neglected, we find a sequence of new branches of axion stars in which gravity is balanced by the mean-field interaction energy of the axion condensate. If mc2 =10-4 4 eV, the first branch of these dense axion stars has mass ranging from about 10-11M⊙ toabout M⊙.

  12. DENSE MEDIUM CYCLONE OPTIMIZATON

    Energy Technology Data Exchange (ETDEWEB)

    Gerald H. Luttrell; Chris J. Barbee; Peter J. Bethell; Chris J. Wood

    2005-06-30

    Dense medium cyclones (DMCs) are known to be efficient, high-tonnage devices suitable for upgrading particles in the 50 to 0.5 mm size range. This versatile separator, which uses centrifugal forces to enhance the separation of fine particles that cannot be upgraded in static dense medium separators, can be found in most modern coal plants and in a variety of mineral plants treating iron ore, dolomite, diamonds, potash and lead-zinc ores. Due to the high tonnage, a small increase in DMC efficiency can have a large impact on plant profitability. Unfortunately, the knowledge base required to properly design and operate DMCs has been seriously eroded during the past several decades. In an attempt to correct this problem, a set of engineering tools have been developed to allow producers to improve the efficiency of their DMC circuits. These tools include (1) low-cost density tracers that can be used by plant operators to rapidly assess DMC performance, (2) mathematical process models that can be used to predict the influence of changes in operating and design variables on DMC performance, and (3) an expert advisor system that provides plant operators with a user-friendly interface for evaluating, optimizing and trouble-shooting DMC circuits. The field data required to develop these tools was collected by conducting detailed sampling and evaluation programs at several industrial plant sites. These data were used to demonstrate the technical, economic and environmental benefits that can be realized through the application of these engineering tools.

  13. Asynchronous event-based binocular stereo matching.

    Science.gov (United States)

    Rogister, Paul; Benosman, Ryad; Ieng, Sio-Hoi; Lichtsteiner, Patrick; Delbruck, Tobi

    2012-02-01

    We present a novel event-based stereo matching algorithm that exploits the asynchronous visual events from a pair of silicon retinas. Unlike conventional frame-based cameras, recent artificial retinas transmit their outputs as a continuous stream of asynchronous temporal events, in a manner similar to the output cells of the biological retina. Our algorithm uses the timing information carried by this representation in addressing the stereo-matching problem on moving objects. Using the high temporal resolution of the acquired data stream for the dynamic vision sensor, we show that matching on the timing of the visual events provides a new solution to the real-time computation of 3-D objects when combined with geometric constraints using the distance to the epipolar lines. The proposed algorithm is able to filter out incorrect matches and to accurately reconstruct the depth of moving objects despite the low spatial resolution of the sensor. This brief sets up the principles for further event-based vision processing and demonstrates the importance of dynamic information and spike timing in processing asynchronous streams of visual events.

  14. Increased Automation in Stereo Camera Calibration Techniques

    Directory of Open Access Journals (Sweden)

    Brandi House

    2006-08-01

    Full Text Available Robotic vision has become a very popular field in recent years due to the numerous promising applications it may enhance. However, errors within the cameras and in their perception of their environment can cause applications in robotics to fail. To help correct these internal and external imperfections, stereo camera calibrations are performed. There are currently many accurate methods of camera calibration available; however, most or all of them are time consuming and labor intensive. This research seeks to automate the most labor intensive aspects of a popular calibration technique developed by Jean-Yves Bouguet. His process requires manual selection of the extreme corners of a checkerboard pattern. The modified process uses embedded LEDs in the checkerboard pattern to act as active fiducials. Images are captured of the checkerboard with the LEDs on and off in rapid succession. The difference of the two images automatically highlights the location of the four extreme corners, and these corner locations take the place of the manual selections. With this modification to the calibration routine, upwards of eighty mouse clicks are eliminated per stereo calibration. Preliminary test results indicate that accuracy is not substantially affected by the modified procedure. Improved automation to camera calibration procedures may finally penetrate the barriers to the use of calibration in practice.

  15. Infrared stereo camera for human machine interface

    Science.gov (United States)

    Edmondson, Richard; Vaden, Justin; Chenault, David

    2012-06-01

    Improved situational awareness results not only from improved performance of imaging hardware, but also when the operator and human factors are considered. Situational awareness for IR imaging systems frequently depends on the contrast available. A significant improvement in effective contrast for the operator can result when depth perception is added to the display of IR scenes. Depth perception through flat panel 3D displays are now possible due to the number of 3D displays entering the consumer market. Such displays require appropriate and human friendly stereo IR video input in order to be effective in the dynamic military environment. We report on a stereo IR camera that has been developed for integration on to an unmanned ground vehicle (UGV). The camera has auto-convergence capability that significantly reduces ill effects due to image doubling, minimizes focus-convergence mismatch, and eliminates the need for the operator to manually adjust camera properties. Discussion of the size, weight, and power requirements as well as integration onto the robot platform will be given along with description of the stand alone operation.

  16. Increased Automation in Stereo Camera Calibration Techniques

    Directory of Open Access Journals (Sweden)

    Brandi House

    2006-08-01

    Full Text Available Robotic vision has become a very popular field in recent years due to the numerous promising applications it may enhance. However, errors within the cameras and in their perception of their environment can cause applications in robotics to fail. To help correct these internal and external imperfections, stereo camera calibrations are performed. There are currently many accurate methods of camera calibration available; however, most or all of them are time consuming and labor intensive. This research seeks to automate the most labor intensive aspects of a popular calibration technique developed by Jean-Yves Bouguet. His process requires manual selection of the extreme corners of a checkerboard pattern. The modified process uses embedded LEDs in the checkerboard pattern to act as active fiducials. Images are captured of the checkerboard with the LEDs on and off in rapid succession. The difference of the two images automatically highlights the location of the four extreme corners, and these corner locations take the place of the manual selections. With this modification to the calibration routine, upwards of eighty mouse clicks are eliminated per stereo calibration. Preliminary test results indicate that accuracy is not substantially affected by the modified procedure. Improved automation to camera calibration procedures may finally penetrate the barriers to the use of calibration in practice.

  17. Stereo topography of Valhalla and Gilgamesh

    Science.gov (United States)

    Schenk, P.; McKinnon, W.; Moore, J.

    1997-03-01

    The geology and morphology of the large multiring impact structures Valhalla and Gilgamesh have been used to infer ways in which the interior structure and properties of the large icy satellites Callisto and Ganymede differ from rocky bodies. These earlier studies were made in the absence of topographic data showing the depths of large impact basins and the degree to which relief has been preserved at large and small scales. Using Voyager stereo images of these basins, we have constructed the first detailed topographic maps of these large basins. These maps reveal the absence of deep topographic depressions, but show that multi-kilometer relief is preserved near the center of Valhalla. Digital Elevation Models (DEM) of these basins were produced using an automated digital stereogrammetry program developed at LPI for use with Voyager and Viking images. The Voyager images used here were obtained from distances of 80,000 to 125,000 km. As a result, the formal vertical resolution for both Valhalla and Gilgamesh maps is about 0.5 km. Relative elevations only are mapped as no global topographic datum exists for the Galilean satellites. In addition, the stereo image models were used to remap the geology and structure of these multiring basins in detail.

  18. Waves near interplanetary shocks observed by STEREO

    Science.gov (United States)

    Aguilar-Rodriguez, E.; Blanco-Cano, X.; Russell, C. T.; Luhmann, J. G.; Krauss-Varban, D.

    2007-12-01

    We investigate the properties of interplanetary shocks that form ahead of virtually all fast propagating coronal mass ejections (CMEs). Understanding the characteristics of these shocks and their surrounding regions is of great interest as they play a major role in the acceleration of solar energetic particles (SEPs). In this work we study low frequency waves upstream and downstream of interplanetary shocks (IP) observed by the twin spacecraft mission STEREO. In the upstream region waves can be generated by ion beams reflected or otherwise energized at the shock. Downstream the wave spectrum may be formed by both, waves generated locally and waves transmitted through the shock.The efficiency of wave generation and wave convection to the shock depends on the shock Mach number, and the angle between the IMF and the shock normal. Waves can disturb the shock and participate in ion acceleration processes. Multi-point STEREO measurements will allow us to study wave characteristics in different regions near IP shocks and determine the effects that these fluctuations have on particle energization.

  19. Simple method for calibrating omnidirectional stereo with multiple cameras

    Science.gov (United States)

    Ha, Jong-Eun; Choi, I.-Sak

    2011-04-01

    Cameras can give useful information for the autonomous navigation of a mobile robot. Typically, one or two cameras are used for this task. Recently, an omnidirectional stereo vision system that can cover the whole surrounding environment of a mobile robot is adopted. They usually adopt a mirror that cannot offer uniform spatial resolution. In this paper, we deal with an omnidirectional stereo system which consists of eight cameras where each two vertical cameras constitute one stereo system. Camera calibration is the first necessary step to obtain 3D information. Calibration using a planar pattern requires many images acquired under different poses so it is a tedious step to calibrate all eight cameras. In this paper, we present a simple calibration procedure using a cubic-type calibration structure that surrounds the omnidirectional stereo system. We can calibrate all the cameras on an omnidirectional stereo system in just one shot.

  20. Merged Shape from Shading and Shape from Stereo for Planetary Topographic Mapping

    Science.gov (United States)

    Tyler, Laurence; Cook, Tony; Barnes, Dave; Parr, Gerhard; Kirk, Randolph

    2014-05-01

    Digital Elevation Models (DEMs) of the Moon and Mars have traditionally been produced from stereo imagery from orbit, or from the surface landers or rovers. One core component of image-based DEM generation is stereo matching to find correspondences between images taken from different viewpoints. Stereo matchers that rely mostly on textural features in the images can fail to find enough matched points in areas lacking in contrast or surface texture. This can lead to blank or topographically noisy areas in resulting DEMs. Fine depth detail may also be lacking due to limited precision and quantisation of the pixel matching process. Shape from shading (SFS), a two dimensional version of photoclinometry, utilizes the properties of light reflecting off surfaces to build up localised slope maps, which can subsequently be combined to extract topography. This works especially well on homogeneous surfaces and can recover fine detail. However the cartographic accuracy can be affected by changes in brightness due to differences in surface material, albedo and light scattering properties, and also by the presence of shadows. We describe here experimental research for the Planetary Robotics Vision Data Exploitation EU FP7 project (PRoViDE) into using stereo generated depth maps in conjunction with SFS to recover both coarse and fine detail of planetary surface DEMs. Our Large Deformation Optimisation Shape From Shading (LDOSFS) algorithm uses image data, illumination, viewing geometry and camera parameters to produce a DEM. A stereo-derived depth map can be used as an initial seed if available. The software uses separate Bidirectional Reflectance Distribution Function (BRDF) and SFS modules for iterative processing and to make the code more portable for future development. Three BRDF models are currently implemented: Lambertian, Blinn-Phong, and Oren-Nayar. A version of the Hapke reflectance function, which is more appropriate for planetary surfaces, is under development

  1. CORRESPONDENCE

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    Dear Editor, Thank you for sending me the ELT Newsletter. My friend recommended the journal to me saying that it was very informative and helpful. Now I am very lucky to be on the mailing list and have got the latest issue. Although I have not finished reading the whole book yet, I believe I have got the right journal I have been longing for. For years, I have been interested in the articles and discussions about the English learning and teaching in China. ELT Newsletter is a wonderful collection of these relevant materials indeed. There is no doubt that every reader like me will benefit from it. I hereby express my heartfelt thanks to you for your excellent work. Guo Peizhi Foshan Education College Foshan, Guangdong

  2. Hyperons in dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Dapo, Haris

    2009-01-28

    The hyperon-nucleon YN low momentum effective interaction (V{sub low} {sub k}) allows for an extensive study of the behavior of hyperons in dense matter, together with an investigation of effects of the presence of hyperons on dense matter. The first step towards this goal is the construction of the matrix elements for the hyperon-nucleon low momentum potential. In order to assess the different properties of hyperons within these potentials we calculate the hyperon single-particle potentials in the Hartree-Fock approximation for all of the interactions. Their dependence on both momentum and density, is studied. The single-particle potentials are then used to determine the chemical potential of hyperons in neutron stars. For nucleonic properties, the nucleon-nucleon V{sub low} {sub k} can be used with the caveat that the calculation of the ground-state energy of symmetric nuclear matter does not correctly reproduce the properties of matter at saturation. With the nucleon-nucleon V{sub low} {sub k} one is unable to reach the densities needed for the calculation of neutron star masses. To circumvent this problem we use two approaches: in the first one, we parametrize the entire nucleonic sector. In the second one, we replace only the three-body force. The former will enable us to study neutron star masses, and the latter for studying the medium's response to the external probe. In this thesis we take the external probe to be the neutrino. By combining this parametrization with the YN V{sub low} {sub k} potential, we calculate the equation of state of equilibrated matter. Performing the calculation in the Hartree-Fock approximation at zero temperature, the concentrations of all particles are calculated. From these we can ascertain at which densities hyperons appear for a wide range of parameters. Finally, we calculate the masses of neutron stars with these concentrations. For the calculation of the medium's response to an external probe, we replace the three

  3. a New Algorithm for Void Filling in a Dsm from Stereo Satellite Images in Urban Areas

    Science.gov (United States)

    Gharib Bafghi, Z.; Tian, J.; d'Angelo, P.; Reinartz, P.

    2016-06-01

    Digital Surface Models (DSM) derived from stereo-pair satellite images are the main sources for many Geo-Informatics applications like 3D change detection, object classification and recognition. However since occlusion especially in urban scenes result in some deficiencies in the stereo matching phase, these DSMs contain some voids. In order to fill the voids a range of algorithms have been proposed, mainly including interpolation alone or along with auxiliary DSM. In this paper an algorithm for void filling in DSM from stereo satellite images has been developed. Unlike common previous approaches we didn't use any external DSM to fill the voids. Our proposed algorithm uses only the original images and the unfilled DSM itself. First a neighborhood around every void in the unfilled DSM and its corresponding area in multispectral image is defined. Then it is analysed to extract both spectral and geometric texture and accordingly to assign labels to each cell in the voids. This step contains three phases comprising shadow detection, height thresholding and image segmentation. Thus every cell in void has a label and is filled by the median value of its co-labelled neighbors. The results for datasets from WorldView-2 and IKONOS are shown and discussed.

  4. A NEW ALGORITHM FOR VOID FILLING IN A DSM FROM STEREO SATELLITE IMAGES IN URBAN AREAS

    Directory of Open Access Journals (Sweden)

    Z. Gharib Bafghi

    2016-06-01

    Full Text Available Digital Surface Models (DSM derived from stereo-pair satellite images are the main sources for many Geo-Informatics applications like 3D change detection, object classification and recognition. However since occlusion especially in urban scenes result in some deficiencies in the stereo matching phase, these DSMs contain some voids. In order to fill the voids a range of algorithms have been proposed, mainly including interpolation alone or along with auxiliary DSM. In this paper an algorithm for void filling in DSM from stereo satellite images has been developed. Unlike common previous approaches we didn’t use any external DSM to fill the voids. Our proposed algorithm uses only the original images and the unfilled DSM itself. First a neighborhood around every void in the unfilled DSM and its corresponding area in multispectral image is defined. Then it is analysed to extract both spectral and geometric texture and accordingly to assign labels to each cell in the voids. This step contains three phases comprising shadow detection, height thresholding and image segmentation. Thus every cell in void has a label and is filled by the median value of its co-labelled neighbors. The results for datasets from WorldView-2 and IKONOS are shown and discussed.

  5. Real-time passenger counting in buses using dense stereovision

    Science.gov (United States)

    Yahiaoui, Tarek; Khoudour, Louahdi; Meurie, Cyril

    2010-07-01

    We are interested particularly in the estimation of passenger flows entering or exiting from buses. To achieve this measurement, we propose a counting system based on stereo vision. To extract three-dimensional information in a reliable way, we use a dense stereo-matching procedure in which the winner-takes-all technique minimizes a correlation score. This score is an improved version of the sum of absolute differences, including several similarity criteria determined on pixels or regions to be matched. After calculating disparity maps for each image, morphological operations and a binarization with multiple thresholds are used to localize the heads of people passing under the sensor. The markers describing the heads of the passengers getting on or off the bus are then tracked during the image sequence to reconstitute their trajectories. Finally, people are counted from these reconstituted trajectories. The technique suggested was validated by several realistic experiments. We showed that it is possible to obtain counting accuracy of 99% and 97% on two large realistic data sets of image sequences showing realistic scenarios.

  6. Stereo and IMU-Assisted Visual Odometry for Small Robots

    Science.gov (United States)

    2012-01-01

    This software performs two functions: (1) taking stereo image pairs as input, it computes stereo disparity maps from them by cross-correlation to achieve 3D (three-dimensional) perception; (2) taking a sequence of stereo image pairs as input, it tracks features in the image sequence to estimate the motion of the cameras between successive image pairs. A real-time stereo vision system with IMU (inertial measurement unit)-assisted visual odometry was implemented on a single 750 MHz/520 MHz OMAP3530 SoC (system on chip) from TI (Texas Instruments). Frame rates of 46 fps (frames per second) were achieved at QVGA (Quarter Video Graphics Array i.e. 320 240), or 8 fps at VGA (Video Graphics Array 640 480) resolutions, while simultaneously tracking up to 200 features, taking full advantage of the OMAP3530's integer DSP (digital signal processor) and floating point ARM processors. This is a substantial advancement over previous work as the stereo implementation produces 146 Mde/s (millions of disparities evaluated per second) in 2.5W, yielding a stereo energy efficiency of 58.8 Mde/J, which is 3.75 better than prior DSP stereo while providing more functionality.

  7. Application of stereo-imaging technology to medical field.

    Science.gov (United States)

    Nam, Kyoung Won; Park, Jeongyun; Kim, In Young; Kim, Kwang Gi

    2012-09-01

    There has been continuous development in the area of stereoscopic medical imaging devices, and many stereoscopic imaging devices have been realized and applied in the medical field. In this article, we review past and current trends pertaining to the application stereo-imaging technologies in the medical field. We describe the basic principles of stereo vision and visual issues related to it, including visual discomfort, binocular disparities, vergence-accommodation mismatch, and visual fatigue. We also present a brief history of medical applications of stereo-imaging techniques, examples of recently developed stereoscopic medical devices, and patent application trends as they pertain to stereo-imaging medical devices. Three-dimensional (3D) stereo-imaging technology can provide more realistic depth perception to the viewer than conventional two-dimensional imaging technology. Therefore, it allows for a more accurate understanding and analysis of the morphology of an object. Based on these advantages, the significance of stereoscopic imaging in the medical field increases in accordance with the increase in the number of laparoscopic surgeries, and stereo-imaging technology plays a key role in the diagnoses of the detailed morphologies of small biological specimens. The application of 3D stereo-imaging technology to the medical field will help improve surgical accuracy, reduce operation times, and enhance patient safety. Therefore, it is important to develop more enhanced stereoscopic medical devices.

  8. STEREO Space Weather and the Space Weather Beacon

    Science.gov (United States)

    Biesecker, D. A.; Webb, D F.; SaintCyr, O. C.

    2007-01-01

    The Solar Terrestrial Relations Observatory (STEREO) is first and foremost a solar and interplanetary research mission, with one of the natural applications being in the area of space weather. The obvious potential for space weather applications is so great that NOAA has worked to incorporate the real-time data into their forecast center as much as possible. A subset of the STEREO data will be continuously downlinked in a real-time broadcast mode, called the Space Weather Beacon. Within the research community there has been considerable interest in conducting space weather related research with STEREO. Some of this research is geared towards making an immediate impact while other work is still very much in the research domain. There are many areas where STEREO might contribute and we cannot predict where all the successes will come. Here we discuss how STEREO will contribute to space weather and many of the specific research projects proposed to address STEREO space weather issues. We also discuss some specific uses of the STEREO data in the NOAA Space Environment Center.

  9. Acquisition of stereo panoramas for display in VR environments

    KAUST Repository

    Ainsworth, Richard A.

    2011-01-23

    Virtual reality systems are an excellent environment for stereo panorama displays. The acquisition and display methods described here combine high-resolution photography with surround vision and full stereo view in an immersive environment. This combination provides photographic stereo-panoramas for a variety of VR displays, including the StarCAVE, NexCAVE, and CORNEA. The zero parallax point used in conventional panorama photography is also the center of horizontal and vertical rotation when creating photographs for stereo panoramas. The two photographically created images are displayed on a cylinder or a sphere. The radius from the viewer to the image is set at approximately 20 feet, or at the object of major interest. A full stereo view is presented in all directions. The interocular distance, as seen from the viewer\\'s perspective, displaces the two spherical images horizontally. This presents correct stereo separation in whatever direction the viewer is looking, even up and down. Objects at infinity will move with the viewer, contributing to an immersive experience. Stereo panoramas created with this acquisition and display technique can be applied without modification to a large array of VR devices having different screen arrangements and different VR libraries.

  10. Ames stereo pipeline-derived digital terrain models of Mercury from MESSENGER stereo imaging

    Science.gov (United States)

    Fassett, Caleb I.

    2016-12-01

    In this study, 96 digital terrain models (DTMs) of Mercury were created using the Ames Stereo Pipeline, using 1456 pairs of stereo images from the Mercury Dual Imaging System instrument on MESSENGER. Although these DTMs cover only 1% of the surface of Mercury, they enable three-dimensional characterization of landforms at horizontal resolutions of 50-250 m/pixel and vertical accuracy of tens of meters. This is valuable in regions where the more precise measurements from the Mercury Laser Altimeter (MLA) are sparse. MLA measurements nonetheless provide an important geodetic framework for the derived stereo products. These DTMs, which are publicly released in conjunction with this paper, reveal topography of features at relatively small scales, including craters, graben, hollows, pits, scarps, and wrinkle ridges. Measurements from these data indicate that: (1) hollows have a median depth of 32 m, in basic agreement with earlier shadow measurement, (2) some of the deep pits (up to 4 km deep) that are interpreted to form via volcanic processes on Mercury have surrounding rims or rises, but others do not, and (3) some pits have two or more distinct, low-lying interior minima that could represent multiple vents.

  11. A stereo vision-based obstacle detection system in vehicles

    Science.gov (United States)

    Huh, Kunsoo; Park, Jaehak; Hwang, Junyeon; Hong, Daegun

    2008-02-01

    Obstacle detection is a crucial issue for driver assistance systems as well as for autonomous vehicle guidance function and it has to be performed with high reliability to avoid any potential collision with the front vehicle. The vision-based obstacle detection systems are regarded promising for this purpose because they require little infrastructure on a highway. However, the feasibility of these systems in passenger car requires accurate and robust sensing performance. In this paper, an obstacle detection system using stereo vision sensors is developed. This system utilizes feature matching, epipoplar constraint and feature aggregation in order to robustly detect the initial corresponding pairs. After the initial detection, the system executes the tracking algorithm for the obstacles. The proposed system can detect a front obstacle, a leading vehicle and a vehicle cutting into the lane. Then, the position parameters of the obstacles and leading vehicles can be obtained. The proposed obstacle detection system is implemented on a passenger car and its performance is verified experimentally.

  12. Bootstrapping the Coronal Magnetic Field with STEREO

    Science.gov (United States)

    Aschwanden, Markus J.

    2010-05-01

    The 3D coronal magnetic field obtained from stereoscopically triangulated loops has been compared with standard photospheric magnetogram extrapolations. We found a large misalignment of 20-40 deg, depending on the complexity of an AR (Sandman et al. 2009; DeRosa et al. 2009). These studies prove that the magnetic field in the photosphere is not force-free and fundamentally cannot reproduce the coronal magnetic field. Bootstrapping with coronal loop 3D geometries are required to improve modeling of the coronal field. Such coronal field bootstrapping methods are currently developed using stereoscopically triangulated loops from STEREO/EUVI and preliminary results show already a significantly reduced misalignment of 10-20 deg.

  13. 'Snow White' Trench After Scraping (Stereo View)

    Science.gov (United States)

    2008-01-01

    This 3D view from the Surface Stereo Imager on NASA's Phoenix Mars Lander shows the trench informally named 'Snow White.' This anaglyph was taken after a series of scrapings by the lander's Robotic Arm on the 58th Martian day, or sol, of the mission (July 23, 2008). The scrapings were done in preparation for collecting a sample for analysis from a hard subsurface layer where soil may contain frozen water. The trench is 4 to 5 centimeters (about 2 inches) deep, about 23 centimeters (9 inches) wide and about 60 centimeters (24 inches) long. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  14. Active stereo vision routines using PRISM-3

    Science.gov (United States)

    Antonisse, Hendrick J.

    1992-11-01

    This paper describes work in progress on a set of visual routines and supporting capabilities implemented on the PRISM-3 real-time vision system. The routines are used in an outdoor robot retrieval task. The task requires the robot to locate a donor agent -- a Hero2000 -- which holds the object to be retrieved, to navigate to the donor, to accept the object from the donor, and return to its original location. The routines described here will form an integral part of the navigation and wide-area search tasks. Active perception is exploited to locate the donor using real-time stereo ranging directed by a pan/tilt/verge mechanism. A framework for orchestrating visual search has been implemented and is briefly described.

  15. Spacetime Stereo and 3D Flow via Binocular Spatiotemporal Orientation Analysis.

    Science.gov (United States)

    Sizintsev, Mikhail; Wildes, Richard P

    2014-11-01

    This paper presents a novel approach to recovering estimates of 3D structure and motion of a dynamic scene from a sequence of binocular stereo images. The approach is based on matching spatiotemporal orientation distributions between left and right temporal image streams, which encapsulates both local spatial and temporal structure for disparity estimation. By capturing spatial and temporal structure in this unified fashion, both sources of information combine to yield disparity estimates that are naturally temporal coherent, while helping to resolve matches that might be ambiguous when either source is considered alone. Further, by allowing subsets of the orientation measurements to support different disparity estimates, an approach to recovering multilayer disparity from spacetime stereo is realized. Similarly, the matched distributions allow for direct recovery of dense, robust estimates of 3D scene flow. The approach has been implemented with real-time performance on commodity GPUs using OpenCL. Empirical evaluation shows that the proposed approach yields qualitatively and quantitatively superior estimates in comparison to various alternative approaches, including the ability to provide accurate multilayer estimates in the presence of (semi)transparent and specular surfaces.

  16. MISR Sees the Sierra Nevadas in Stereo

    Science.gov (United States)

    2000-01-01

    These MISR images of the Sierra Nevada mountains near the California-Nevada border were acquired on August 12, 2000 during Terra orbit 3472. On the left is an image from the vertical-viewing (nadir) camera. On the right is a stereo 'anaglyph' created using the nadir and 45.6-degree forward-viewing cameras, providing a three-dimensional view of the scene when viewed with red/blue glasses. The red filter should be placed over your left eye. To facilitate the stereo viewing, the images have been oriented with north toward the left.Some prominent features are Mono Lake, in the center of the images; Walker Lake, to its left; and Lake Tahoe, near the lower left. This view of the Sierra Nevadas includes Yosemite, Kings Canyon, and Sequoia National Parks. Mount Whitney, the highest peak in the contiguous 48 states (elev. 14,495 feet), is visible near the righthand edge. Above it (to the east), the Owens Valley shows up prominently between the Sierra Nevada and Inyo ranges.Precipitation falling as rain or snow on the Sierras feeds numerous rivers flowing southwestward into the San Joaquin Valley. The abundant fields of this productive agricultural area can be seen along the lower right; a large number of reservoirs that supply water for crop irrigation are apparent in the western foothills of the Sierras. Urban areas in the valley appear as gray patches; among the California cities that are visible are Fresno, Merced, and Modesto.MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  17. Sterile neutrino search in the STEREO experiment

    Energy Technology Data Exchange (ETDEWEB)

    Buck, Christian; Lindner, Manfred; Roca, Christian [MPIK (Germany)

    2016-07-01

    In neutrino oscillations, a canonical understanding has been established during the last decades after the measurement of the mixing angles θ{sub 12}, θ{sub 23}, θ{sub 13} via solar, atmospheric and, most recently, reactor neutrinos. However, the re-evaluation of the reactor neutrino theoretical flux has forced a re-analysis of most reactor neutrino measurements at short distances. This has led to an unexpected experimental deficit of neutrinos with respect to the theory that needs to be accommodated, commonly known as the ''reactor neutrino anomaly''. This deficit can be interpreted as the existence of a light sterile neutrino state into which reactor neutrinos oscillate at very short distances. The STEREO experiment aims to find an evidence of such oscillations. The ILL research reactor in Grenoble (France) operates at a power of 58MW and provides a large flux of electron antineutrinos with an energy range of a few MeV. These neutrinos will be detected in a 2000 liter organic liquid scintillator detector doped with Gadolinium and consisting of 6 cells stacked along the direction of the core. Given the proximity of the detector, neutrinos will only travel a few meters until they interact with the scintillator. The detector will be placed about 10 m from the reactor core, allowing STEREO to be sensitive to oscillations into the above mentioned neutrino sterile state. The project presents a high potential for a discovery that would impact deeply the paradigms of neutrino oscillations and in consequence the current understanding of particle physics and cosmology.

  18. Runtime Analysis of GPU-Based Stereo Matching

    Directory of Open Access Journals (Sweden)

    Christian Zentner

    2015-11-01

    Full Text Available This paper elaborates on the possibility to leverage the highly parallel nature of GPUs to implement more efficient stereo matching algorithms. Different algorithms have been implemented and compared on the CPU and the GPU in order to show the speedup gained by moving the computation to the graphics card. The results were evaluated for accuracy using the test available on the Middlebury website for stereo vision. An assessment of the runtime performance was done by a script which examined the runtime behaviour of the individual steps of the stereo matching algorithm.

  19. Method for Stereo Mapping Based on Objectarx and Pipeline Technology

    Science.gov (United States)

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

    2012-07-01

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

  20. A Stereo Dual-Channel Dynamic Programming Algorithm for UAV Image Stitching.

    Science.gov (United States)

    Li, Ming; Chen, Ruizhi; Zhang, Weilong; Li, Deren; Liao, Xuan; Wang, Lei; Pan, Yuanjin; Zhang, Peng

    2017-09-08

    Dislocation is one of the major challenges in unmanned aerial vehicle (UAV) image stitching. In this paper, we propose a new algorithm for seamlessly stitching UAV images based on a dynamic programming approach. Our solution consists of two steps: Firstly, an image matching algorithm is used to correct the images so that they are in the same coordinate system. Secondly, a new dynamic programming algorithm is developed based on the concept of a stereo dual-channel energy accumulation. A new energy aggregation and traversal strategy is adopted in our solution, which can find a more optimal seam line for image stitching. Our algorithm overcomes the theoretical limitation of the classical Duplaquet algorithm. Experiments show that the algorithm can effectively solve the dislocation problem in UAV image stitching, especially for the cases in dense urban areas. Our solution is also direction-independent, which has better adaptability and robustness for stitching images.

  1. A Stereo Matching Algorithm Based on Four-Mo ded Census and Relative Confidence Plane Fitting

    Institute of Scientific and Technical Information of China (English)

    MEN Yubo; ZHANG Guoyin; MEN Chaoguang; LI Xiang; MA Ning

    2015-01-01

    A four-moded Census transform stereo matching algorithm using bidirectional constraint dynamic programming and relative confidence plane fitting is pro-posed to solve the problems of matching quality. Using the four-moded Census transform which adds a restrictive condition replaces traditional Census transform to improve matching accuracy and mean value of all pixels intensity replaces the center pixel intensity in the Census window to solve the problem of the center pixel distortion eff ectively, a refined initial local matching cost can be obtained. Dur-ing the disparity optimization, the difficulty of disparity computation in textureless areas is overcome by the esti-mated condition and defined relative confident pixels. Ex-periment results show that a better dense matching map can be obtained by the proposed algorithm.

  2. Multiple candidates and multiple constraints based accurate depth estimation for multi-view stereo

    Science.gov (United States)

    Zhang, Chao; Zhou, Fugen; Xue, Bindang

    2017-02-01

    In this paper, we propose a depth estimation method for multi-view image sequence. To enhance the accuracy of dense matching and reduce the inaccurate matching which is produced by inaccurate feature description, we select multiple matching points to build candidate matching sets. Then we compute an optimal depth from a candidate matching set which satisfies multiple constraints (epipolar constraint, similarity constraint and depth consistency constraint). To further increase the accuracy of depth estimation, depth consistency constraint of neighbor pixels is used to filter the inaccurate matching. On this basis, in order to get more complete depth map, depth diffusion is performed by neighbor pixels' depth consistency constraint. Through experiments on the benchmark datasets for multiple view stereo, we demonstrate the superiority of proposed method over the state-of-the-art method in terms of accuracy.

  3. Conductive dense hydrogen

    Science.gov (United States)

    Eremets, M.; Troyan, I.

    2012-12-01

    Hydrogen at ambient pressures and low temperatures forms a molecular crystal which is expected to display metallic properties under megabar pressures. This metal is predicted to be superconducting with a very high critical temperature Tc of 200-400 K. The superconductor may potentially be recovered metastably at ambient pressures, and it may acquire a new quantum state as a metallic superfluid and a superconducting superfluid. Recent experiments performed at low temperatures T 220 GPa, new Raman modes arose, providing evidence for the transformation to a new opaque and electrically conductive phase IV. Above 260 GPa, in the next phase V, hydrogen reflected light well. Its resistance was nearly temperature-independent over a wide temperature range, down to 30 K, indicating that the hydrogen was metallic. Releasing the pressure induced the metallic phase to transform directly into molecular hydrogen with significant hysteresis at 200 GPa and 295 K. These data were published in our paper: M. I. Eremets and I. A. Troyan "Conductive dense hydrogen." Nature Materials 10: 927-931. We will present also new results on hydrogen: phase diagram with phases IV and V determined in P,T domain up to 300 GPa and 350 K. We will also discuss possible structures of phase IV based on our Raman and infrared measurements up to 300 GPa.

  4. Dense Hypervelocity Plasma Jets

    Science.gov (United States)

    Case, Andrew; Witherspoon, F. Douglas; Messer, Sarah; Bomgardner, Richard; Phillips, Michael; van Doren, David; Elton, Raymond; Uzun-Kaymak, Ilker

    2007-11-01

    We are developing high velocity dense plasma jets for fusion and HEDP applications. Traditional coaxial plasma accelerators suffer from the blow-by instability which limits the mass accelerated to high velocity. In the current design blow-by is delayed by a combination of electrode shaping and use of a tailored plasma armature created by injection of a high density plasma at a few eV generated by arrays of capillary discharges or sparkgaps. Experimental data will be presented for a complete 32 injector gun system built for driving rotation in the Maryland MCX experiment, including data on penetration of the plasma jet through a magnetic field. We present spectroscopic measurements of plasma velocity, temperature, and density, as well as total momentum measured using a ballistic pendulum. Measurements are in agreement with each other and with time of flight data from photodiodes and a multichannel PMT. Plasma density is above 10^15 cm-3, velocities range up to about 100 km/s. Preliminary results from a quadrature heterodyne HeNe interferometer are consistent with these results.

  5. Obstacles facing the venus radar mapper - The implications of gestalt formation in stereo-radargrammetry

    Science.gov (United States)

    Wildey, R.L.

    1986-01-01

    The question of adapting to radar images the existing hardware that form topographic maps through stereo-photogrammetric models, is examined in principle. Such hardware utilizes a human/ computer hybrid. Although the problem of brightness differentials between corresponding landmarks can be dealt with pseudo-photoclinometrically, the main problem is whether the perspective in a radar image can be conceived to mimic that of a photographic image obtained by a suitably positioned camera. This conception is found to be possible, providing the characteristic relief subtends to a very small angle at the radar and at the fictitious camera. The photogrammetric model parameters must be determined a priori. ?? 1986 D. Reidel Publishing Company.

  6. Dense 3d Point Cloud Generation from Uav Images from Image Matching and Global Optimazation

    Science.gov (United States)

    Rhee, S.; Kim, T.

    2016-06-01

    3D spatial information from unmanned aerial vehicles (UAV) images is usually provided in the form of 3D point clouds. For various UAV applications, it is important to generate dense 3D point clouds automatically from over the entire extent of UAV images. In this paper, we aim to apply image matching for generation of local point clouds over a pair or group of images and global optimization to combine local point clouds over the whole region of interest. We tried to apply two types of image matching, an object space-based matching technique and an image space-based matching technique, and to compare the performance of the two techniques. The object space-based matching used here sets a list of candidate height values for a fixed horizontal position in the object space. For each height, its corresponding image point is calculated and similarity is measured by grey-level correlation. The image space-based matching used here is a modified relaxation matching. We devised a global optimization scheme for finding optimal pairs (or groups) to apply image matching, defining local match region in image- or object- space, and merging local point clouds into a global one. For optimal pair selection, tiepoints among images were extracted and stereo coverage network was defined by forming a maximum spanning tree using the tiepoints. From experiments, we confirmed that through image matching and global optimization, 3D point clouds were generated successfully. However, results also revealed some limitations. In case of image-based matching results, we observed some blanks in 3D point clouds. In case of object space-based matching results, we observed more blunders than image-based matching ones and noisy local height variations. We suspect these might be due to inaccurate orientation parameters. The work in this paper is still ongoing. We will further test our approach with more precise orientation parameters.

  7. Heavy mesons in dense matter

    NARCIS (Netherlands)

    Tolos, Laura; Gamermann, Daniel; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; LlanesEstrada, FJ; Pelaez,

    2011-01-01

    Charmed mesons in dense matter are studied within a unitary coupled-channel approach which takes into account Pauli-blocking effects and meson self-energies in a self-consistent manner. We obtain the open-charm meson spectral functions in this dense medium, and discuss their implications on hidden c

  8. MISR Level 2 TOA/Cloud Stereo parameters V002

    Data.gov (United States)

    National Aeronautics and Space Administration — This is the Level 2 TOA/Cloud Stereo Product. It contains the Stereoscopically Derived Cloud Mask (SDCM), cloud winds, Reflecting Level Reference Altitude (RLRA),...

  9. Teater (stereo)tüüpide loojana / Anneli Saro

    Index Scriptorium Estoniae

    Saro, Anneli, 1968-

    2006-01-01

    Tutvustatakse 27. märtsil Tartu Ülikooli ajaloomuuseumis toimuva Eesti Teatriuurijate Ühenduse ning TÜ teatriteaduse ja kirjandusteooria õppetooli korraldatud konverentsi "Teater sotsiaalsete ja kultuuriliste (stereo)tüüpide loojana" teemasid

  10. Method of stereo matching based on genetic algorithm

    Science.gov (United States)

    Lu, Chaohui; An, Ping; Zhang, Zhaoyang

    2003-09-01

    A new stereo matching scheme based on image edge and genetic algorithm (GA) is presented to improve the conventional stereo matching method in this paper. In order to extract robust edge feature for stereo matching, infinite symmetric exponential filter (ISEF) is firstly applied to remove the noise of image, and nonlinear Laplace operator together with local variance of intensity are then used to detect edges. Apart from the detected edge, the polarity of edge pixels is also obtained. As an efficient search method, genetic algorithm is applied to find the best matching pair. For this purpose, some new ideas are developed for applying genetic algorithm to stereo matching. Experimental results show that the proposed methods are effective and can obtain good results.

  11. Clustered features for use in stereo vision SLAM

    CSIR Research Space (South Africa)

    Joubert, D

    2010-07-01

    Full Text Available SLAM, or simultaneous localization and mapping, is a key component in the development of truly independent robots. Vision-based SLAM utilising stereo vision is a promising approach to SLAM but it is computationally expensive and difficult...

  12. Infrared stereo calibration for unmanned ground vehicle navigation

    Science.gov (United States)

    Harguess, Josh; Strange, Shawn

    2014-06-01

    The problem of calibrating two color cameras as a stereo pair has been heavily researched and many off-the-shelf software packages, such as Robot Operating System and OpenCV, include calibration routines that work in most cases. However, the problem of calibrating two infrared (IR) cameras for the purposes of sensor fusion and point could generation is relatively new and many challenges exist. We present a comparison of color camera and IR camera stereo calibration using data from an unmanned ground vehicle. There are two main challenges in IR stereo calibration; the calibration board (material, design, etc.) and the accuracy of calibration pattern detection. We present our analysis of these challenges along with our IR stereo calibration methodology. Finally, we present our results both visually and analytically with computed reprojection errors.

  13. Direct stereo radargrammetric processing using massively parallel processing

    Science.gov (United States)

    Balz, Timo; Zhang, Lu; Liao, Mingsheng

    2013-05-01

    Synthetic Aperture Radar (SAR) offers many ways to reconstruct digital surface models (DSMs). The two most commonly used methods are SAR interferometry (InSAR) and stereo radargrammetry. Stereo radargrammetry is a very stable and reliable process and is far less affected by temporal decorrelation compared with InSAR. It is therefore often used for DSM generation in heavily vegetated areas. However, stereo radargrammetry often produces rather noisy DSMs, sometimes containing large outliers. In this manuscript, we present a new approach for stereo radargrammetric processing, where the homologous points between the images are found by geocoding large amount of points. This offers a very flexible approach, allowing the simultaneous processing of multiple images and of cross-heading image pairs. Our approach relies on a good initial geocoding accuracy of the data and on very fast processing using a massively parallel implementation. The approach is demonstrated using TerraSAR-X images from Mount Song, China, and from Trento, Italy.

  14. Teater (stereo)tüüpide loojana / Anneli Saro

    Index Scriptorium Estoniae

    Saro, Anneli, 1968-

    2006-01-01

    Tutvustatakse 27. märtsil Tartu Ülikooli ajaloomuuseumis toimuva Eesti Teatriuurijate Ühenduse ning TÜ teatriteaduse ja kirjandusteooria õppetooli korraldatud konverentsi "Teater sotsiaalsete ja kultuuriliste (stereo)tüüpide loojana" teemasid

  15. DEM EXTRACTION FROM WORLDVIEW-3 STEREO-IMAGES AND ACCURACY EVALUATION

    Directory of Open Access Journals (Sweden)

    F. Hu

    2016-06-01

    Full Text Available This paper validates the potentials of Worldview-3 satellite images in large scale topographic mapping, by choosing Worldview-3 along-track stereo-images of Yi Mountain area in Shandong province China for DEM extraction and accuracy evaluation. Firstly, eighteen accurate and evenly-distributed GPS points are collected in field and used as GCPs/check points, the image points of which are accurately measured, and also tie points are extracted from image matching; then, the RFM-based block adjustment to compensate the systematic error in image orientation is carried out and the geo-positioning accuracy is calculated and analysed; next, for the two stereo-pairs of the block, DSMs are separately constructed and mosaicked as an entirety, and also the corresponding DEM is subsequently generated; finally, compared with the selected check points from high-precision airborne LiDAR point cloud covering the same test area, the accuracy of the generated DEM with 2-meter grid spacing is evaluated by the maximum (max., minimum (min., mean and standard deviation (std. values of elevation biases. It is demonstrated that, for Worldview-3 stereo-images used in our research, the planimetric accuracy without GCPs is about 2.16 m (mean error and 0.55 (std. error, which is superior to the nominal value, while the vertical accuracy is about -1.61 m (mean error and 0.49 m (std. error; with a small amount of GCPs located in the center and four corners of the test area, the systematic error can be well compensated. The std. value of elevation biases between the generated DEM and the 7256 LiDAR check points are about 0.62 m. If considering the potential uncertainties in the image point measurement, stereo matching and also elevation editing, the accuracy of generating DEM from Worldview-3 stereo-images should be more desirable. Judging from the results, Worldview-3 has the potential for 1:5000 or even larger scale mapping application.

  16. Dem Extraction from WORLDVIEW-3 Stereo-Images and Accuracy Evaluation

    Science.gov (United States)

    Hu, F.; Gao, X. M.; Li, G. Y.; Li, M.

    2016-06-01

    This paper validates the potentials of Worldview-3 satellite images in large scale topographic mapping, by choosing Worldview-3 along-track stereo-images of Yi Mountain area in Shandong province China for DEM extraction and accuracy evaluation. Firstly, eighteen accurate and evenly-distributed GPS points are collected in field and used as GCPs/check points, the image points of which are accurately measured, and also tie points are extracted from image matching; then, the RFM-based block adjustment to compensate the systematic error in image orientation is carried out and the geo-positioning accuracy is calculated and analysed; next, for the two stereo-pairs of the block, DSMs are separately constructed and mosaicked as an entirety, and also the corresponding DEM is subsequently generated; finally, compared with the selected check points from high-precision airborne LiDAR point cloud covering the same test area, the accuracy of the generated DEM with 2-meter grid spacing is evaluated by the maximum (max.), minimum (min.), mean and standard deviation (std.) values of elevation biases. It is demonstrated that, for Worldview-3 stereo-images used in our research, the planimetric accuracy without GCPs is about 2.16 m (mean error) and 0.55 (std. error), which is superior to the nominal value, while the vertical accuracy is about -1.61 m (mean error) and 0.49 m (std. error); with a small amount of GCPs located in the center and four corners of the test area, the systematic error can be well compensated. The std. value of elevation biases between the generated DEM and the 7256 LiDAR check points are about 0.62 m. If considering the potential uncertainties in the image point measurement, stereo matching and also elevation editing, the accuracy of generating DEM from Worldview-3 stereo-images should be more desirable. Judging from the results, Worldview-3 has the potential for 1:5000 or even larger scale mapping application.

  17. Revisiting STEREO interplanetary and interstellar dust flux and mass estimates

    Science.gov (United States)

    Malaspina, David M.; O'Brien, Leela E.; Thayer, Frederick; Sternovsky, Zoltan; Collette, Andrew

    2015-08-01

    Two recent events have motivated a second look at estimates for the flux and mass of approximately micron-radius interplanetary and interstellar dust observed by the twin STEREO spacecraft. First, the signals interpreted as nanometer dust impacts on STEREO-A have nearly ceased, even though STEREO-B continues to observe these signals unabated. Second, a recent laboratory dust accelerator experimental campaign has quantified the charge release associated with hypervelocity dust impacts on materials specific to STEREO. The first event enables an investigation of the extent to which nanometer dust signals influence estimates of micron-radius dust flux. The second event allows an evaluation of how impact charge release values specific to STEREO materials influence dust mass estimates. Revised estimates based on these considerations yield higher fluxes and similar masses for micron-radius interplanetary dust compared to prior studies, as well as lower fluxes and higher masses for interstellar micron-radius dust compared to prior studies. The revised flux and mass estimates reported here differ by less than a factor of 4 from those reported in previous work, demonstrating that STEREO-derived estimates for the flux and mass of micron-radius dust are largely robust to spacecraft material charge yields and the disappearance of nanometer dust signals.

  18. Extracting a high-quality data space for stereo-tomography based on a 3D structure tensor algorithm and kinematic de-migration

    Science.gov (United States)

    Xiong, Kai; Yang, Kai; Wang, Yu-Xiang

    2017-08-01

    To extract a high-quality data space (the so-called kinematic invariants) is a key factor to a successful implementation of stereo-tomography. The structure tensor algorithm demonstrated itself a robust tool to pick the kinematic invariants for stereo-tomography. However, if there are lots of diffractions and other noises in the data, it could be risky to extract the data space from the data domain. Meanwhile, for any reflector, we try to pick all the relevant primary reflections as much as possible within a wide offset range. To achieve this, in this paper, we design a scheme to extract a high-quality data space for stereo-tomography based on 3D structure tensor and kinematic de-migration. Firstly, we apply an automatic, dense volumetric picking for residual move-out (RMO) and the structural dip in the depth-migrated domain with an advanced 3D structure tensor algorithm. Then, a set of key horizons are picked manually in a few selected depth-migrated common offset gathers. Finally, all the picked horizons are extrapolated along the offset axis based on the RMO information picked in advance. Thus, the initial high-density points picked in the depth-migrated volume are greatly refined. After this processing, a final and refined data space for stereo-tomography is extracted through a kinematic de-migration. We demonstrate the correctness and the robustness of the presented scheme with synthetic and real data examples.

  19. Image-Guided Non-Local Dense Matching with Three-Steps Optimization

    Science.gov (United States)

    Huang, Xu; Zhang, Yongjun; Yue, Zhaoxi

    2016-06-01

    This paper introduces a new image-guided non-local dense matching algorithm that focuses on how to solve the following problems: 1) mitigating the influence of vertical parallax to the cost computation in stereo pairs; 2) guaranteeing the performance of dense matching in homogeneous intensity regions with significant disparity changes; 3) limiting the inaccurate cost propagated from depth discontinuity regions; 4) guaranteeing that the path between two pixels in the same region is connected; and 5) defining the cost propagation function between the reliable pixel and the unreliable pixel during disparity interpolation. This paper combines the Census histogram and an improved histogram of oriented gradient (HOG) feature together as the cost metrics, which are then aggregated based on a new iterative non-local matching method and the semi-global matching method. Finally, new rules of cost propagation between the valid pixels and the invalid pixels are defined to improve the disparity interpolation results. The results of our experiments using the benchmarks and the Toronto aerial images from the International Society for Photogrammetry and Remote Sensing (ISPRS) show that the proposed new method can outperform most of the current state-of-the-art stereo dense matching methods.

  20. An on-line calibration algorithm for external parameters of visual system based on binocular stereo cameras

    Science.gov (United States)

    Wang, Liqiang; Liu, Zhen; Zhang, Zhonghua

    2014-11-01

    Stereo vision is the key in the visual measurement, robot vision, and autonomous navigation. Before performing the system of stereo vision, it needs to calibrate the intrinsic parameters for each camera and the external parameters of the system. In engineering, the intrinsic parameters remain unchanged after calibrating cameras, and the positional relationship between the cameras could be changed because of vibration, knocks and pressures in the vicinity of the railway or motor workshops. Especially for large baselines, even minute changes in translation or rotation can affect the epipolar geometry and scene triangulation to such a degree that visual system becomes disabled. A technology including both real-time examination and on-line recalibration for the external parameters of stereo system becomes particularly important. This paper presents an on-line method for checking and recalibrating the positional relationship between stereo cameras. In epipolar geometry, the external parameters of cameras can be obtained by factorization of the fundamental matrix. Thus, it offers a method to calculate the external camera parameters without any special targets. If the intrinsic camera parameters are known, the external parameters of system can be calculated via a number of random matched points. The process is: (i) estimating the fundamental matrix via the feature point correspondences; (ii) computing the essential matrix from the fundamental matrix; (iii) obtaining the external parameters by decomposition of the essential matrix. In the step of computing the fundamental matrix, the traditional methods are sensitive to noise and cannot ensure the estimation accuracy. We consider the feature distribution situation in the actual scene images and introduce a regional weighted normalization algorithm to improve accuracy of the fundamental matrix estimation. In contrast to traditional algorithms, experiments on simulated data prove that the method improves estimation

  1. Quantum Painleve-Calogero Correspondence

    CERN Document Server

    Zabrodin, A

    2011-01-01

    The Painleve-Calogero correspondence is extended to auxiliary linear problems associated with Painleve equations. The linear problems are represented in a new form which has a suggestive interpretation as a "quantized" version of the Painleve-Calogero correspondence. Namely, the linear problem responsible for the time evolution is brought into the form of non-stationary Schrodinger equation in imaginary time, $\\p_t \\psi =(1/2\\, \\p_x^2 +V(x,t))\\psi$, whose Hamiltonian is a natural quantization of the classical Calogero-like Hamiltonian $H=1/2\\, p^2 +V(x,t)$ for the corresponding Painleve equation.

  2. Plaque characterization in ex vivo MRI evaluated by dense 3D correspondence with histology

    DEFF Research Database (Denmark)

    van Engelen, Arna; de Bruijne, Marleen; Klein, Stefan;

    2011-01-01

    Automatic quantification of carotid artery plaque composition is important in the development of methods that distinguish vulnerable from stable plaques. MRI has shown to be capable of imaging different components noninvasively. We present a new plaque classification method which uses 3D registra...

  3. Densely crosslinked polycarbosiloxanes .1. Synthesis

    NARCIS (Netherlands)

    Flipsen, T.A C; Derks, R.; van der Vegt, H.A.; Pennings, A.J; Hadziioannou, G

    1997-01-01

    Novel densely crosslinked polycarbosiloxanes were obtained by using functional branched prepolymers. Two types of soluble prepolymers were prepared from di- and trifunctional alkoxysilane monomers via cohydrolysis/condensation and for both final crosslinking occurred via hydrosilylation. The prepoly

  4. Coherence and correspondence in medicine

    Directory of Open Access Journals (Sweden)

    Thomas G. Tape

    2009-03-01

    Full Text Available Many controversies in medical science can be framed as tension between a coherence approach (which seeks logic and explanation and a correspondence approach (which emphasizes empirical correctness. In many instances, a coherence-based theory leads to an understanding of disease that is not supported by empirical evidence. Physicians and patients alike tend to favor the coherence approach even in the face of strong, contradictory correspondence evidence. Examples include the management of atrial fibrillation, treatment of acute bronchitis, and the use of Vitamin E to prevent heart disease. Despite the frequent occurrence of controversy stemming from coherence-correspondence conflicts, medical professionals are generally unaware of these terms and the philosophical traditions that underlie them. Learning about the coherence-correspondence distinction and using the best of both approaches could not only help reconcile controversy but also lead to striking advances in medical science.

  5. Valentine Wilderness Proposal Conflict Correspondence

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Correspondence on the issue of grazing permits at Valentine National Wildlife Refuge in relation witht the proposed wilderness. Document also contains the Public...

  6. Dense energetic nitraminofurazanes.

    Science.gov (United States)

    Fischer, Dennis; Klapötke, Thomas M; Reymann, Marius; Stierstorfer, Jörg

    2014-05-19

    3,3'-Diamino-4,4'-bifurazane (1), 3,3'-diaminoazo-4,4'-furazane (2), and 3,3'-diaminoazoxy-4,4'-furazane (3) were nitrated in 100 % HNO3 to give corresponding 3,3'-dinitramino-4,4'-bifurazane (4), 3,3'-dinitramino-4,4'-azofurazane (5) and 3,3'-dinitramino-4,4'-azoxyfurazane (6), respectively. The neutral compounds show very imposing explosive performance but possess lower thermal stability and higher sensitivity than hexogen (RDX). More than 40 nitrogen-rich compounds and metal salts were prepared. Most compounds were characterized by low-temperature X-ray diffraction, all of them by infrared and Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, and by differential scanning calorimetry (DSC). Calculated energetic performances using the EXPLO5 code based on calculated (CBS-4M) heats of formation and X-ray densities support the high energetic performances of the nitraminofurazanes as energetic materials. The sensitivities towards impact, friction, and electrostatic discharge were also explored. Additionally the general toxicity of the anions against vibrio fischeri, representative for an aquatic microorganism, was determined.

  7. Small Orbital Stereo Tracking Camera Technology Development

    Science.gov (United States)

    Bryan, Tom; MacLeod, Todd; Gagliano, Larry

    2017-01-01

    Any exploration vehicle assembled or Spacecraft placed in LEO or GTO must pass through this debris cloud and survive. Large cross section, low thrust vehicles will spend more time spiraling out through the cloud and will suffer more impacts.Better knowledge of small debris will improve survival odds. Current estimated Density of debris at various orbital attitudes with notation of recent collisions and resulting spikes. Orbital Debris Tracking and Characterization has now been added to NASA Office of Chief Technologists Technology Development Roadmap in Technology Area 5 (TA5.7)[Orbital Debris Tracking and Characterization] and is a technical gap in the current National Space Situational Awareness necessary to safeguard orbital assets and crews due to the risk of Orbital Debris damage to ISS Exploration vehicles. The Problem: Traditional orbital trackers looking for small, dim orbital derelicts and debris typically will stare at the stars and let any reflected light off the debris integrate in the imager for seconds, thus creating a streak across the image. The Solution: The Small Tracker will see Stars and other celestial objects rise through its Field of View (FOV) at the rotational rate of its orbit, but the glint off of orbital objects will move through the FOV at different rates and directions. Debris on a head-on collision course (or close) will stay in the FOV at 14 Km per sec. The Small Tracker can track at 60 frames per sec allowing up to 30 fixes before a near-miss pass. A Stereo pair of Small Trackers can provide range data within 5-7 Km for better orbit measurements.

  8. Interior channels in Martian valleys: Constraints on fluvial erosion by measurements of the Mars Express High Resolution Stereo Camera

    Science.gov (United States)

    Jaumann, R.; Reiss, D.; Frei, S.; Neukum, G.; Scholten, F.; Gwinner, K.; Roatsch, T.; Matz, K.-D.; Mertens, V.; Hauber, E.; Hoffmann, H.; Köhler, U.; Head, J. W.; Hiesinger, H.; Carr, M. H.

    2005-08-01

    In High Resolution Stereo Camera (HRSC) images of the Mars Express Mission a 130 km long interior channel is identified within a 400 km long valley network system located in the Lybia Montes. Ages of the valley floor and the surroundings as derived from crater counts define a period of ~350 Myrs during which the valley might have been formed. Based on HRSC stereo measurements the discharge of the interior channel is estimated at ~4800 m3/s, corresponding to a runoff production rate of ~1 cm/day. Mass balances indicate erosion rates of a few cm/year implying the erosion activity in the valley to a few thousand years for continuous flow, or one or more orders of magnitude longer time spans for more intermittent flows. Therefore, during the Hesperian, relatively brief but recurring episodes of erosion intervals are more likely than sustained flow.

  9. An automated, open-source pipeline for mass production of digital elevation models (DEMs) from very-high-resolution commercial stereo satellite imagery

    Science.gov (United States)

    Shean, David E.; Alexandrov, Oleg; Moratto, Zachary M.; Smith, Benjamin E.; Joughin, Ian R.; Porter, Claire; Morin, Paul

    2016-06-01

    We adapted the automated, open source NASA Ames Stereo Pipeline (ASP) to generate digital elevation models (DEMs) and orthoimages from very-high-resolution (VHR) commercial imagery of the Earth. These modifications include support for rigorous and rational polynomial coefficient (RPC) sensor models, sensor geometry correction, bundle adjustment, point cloud co-registration, and significant improvements to the ASP code base. We outline a processing workflow for ∼0.5 m ground sample distance (GSD) DigitalGlobe WorldView-1 and WorldView-2 along-track stereo image data, with an overview of ASP capabilities, an evaluation of ASP correlator options, benchmark test results, and two case studies of DEM accuracy. Output DEM products are posted at ∼2 m with direct geolocation accuracy of computing environment. We are leveraging these resources to produce dense time series and regional mosaics for the Earth's polar regions.

  10. The gravity/CFT correspondence

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Henrique [University of California at Davis, Davis, CA (United States); Gryb, Sean [Utrecht University, Utrecht (Netherlands); Koslowski, Tim [Perimeter Institute for Theoretical Physics, Waterloo, Ontario (Canada); University of New Brunswick, Dept. of Mathematics and Statistics, Fredericton, New Brunswick (Canada); Mercati, Flavio [Perimeter Institute for Theoretical Physics, Waterloo, Ontario (Canada); Universidad de Zaragoza, Departamento de Fisica Teorica, Zaragoza (Spain); University of Nottingham, School of Mathematical Sciences, Nottingham (United Kingdom)

    2013-01-15

    General Relativity can be formulated in terms of a spatially Weyl invariant gauge theory called Shape Dynamics. Using this formulation, we establish a ''bulk/bulk'' duality between gravity and a Weyl invariant theory on spacelike Cauchy hypersurfaces. This duality has two immediate consequences: (i) it leads trivially to a corresponding ''bulk/boundary'' duality between General Relativity and a boundary CFT, and (ii) the boundary can be defined in a gauge-invariant way. Moreover, the corresponding bulk/boundary duality is sufficient to explain a large portion of the evidence in favor of gauge/gravity duality and provides independent evidence for the AdS/CFT correspondence. (orig.)

  11. Quantum Painleve-Calogero correspondence

    Energy Technology Data Exchange (ETDEWEB)

    Zabrodin, A. [National Research University Higher School of Economics, 20 Myasnitskaya Ulitsa, Moscow 101000 (Russian Federation); Institute of Biochemical Physics, Kosygina str. 4, 119991 Moscow (Russian Federation) and ITEP, Bol. Cheremushkinskaya str. 25, 117259 Moscow (Russian Federation); Zotov, A. [ITEP, Bol. Cheremushkinskaya str. 25, 117259 Moscow (Russian Federation)

    2012-07-15

    The Painleve-Calogero correspondence is extended to auxiliary linear problems associated with Painleve equations. The linear problems are represented in a new form which has a suggestive interpretation as a 'quantized' version of the Painleve-Calogero correspondence. Namely, the linear problem responsible for the time evolution is brought into the form of non-stationary Schroedinger equation in imaginary time, {partial_derivative}{sub t}{psi}=((1/2) {partial_derivative}{sub x}{sup 2}+V(x,t)){psi}, whose Hamiltonian is a natural quantization of the classical Calogero-like Hamiltonian H=(1/2) p{sup 2}+V(x,t) for the corresponding Painleve equation. In present paper, we present explicit constructions for the first five equations from the Painleve list.

  12. Enhancement Strategies for Frame-To Uas Stereo Visual Odometry

    Science.gov (United States)

    Kersten, J.; Rodehorst, V.

    2016-06-01

    Autonomous navigation of indoor unmanned aircraft systems (UAS) requires accurate pose estimations usually obtained from indirect measurements. Navigation based on inertial measurement units (IMU) is known to be affected by high drift rates. The incorporation of cameras provides complementary information due to the different underlying measurement principle. The scale ambiguity problem for monocular cameras is avoided when a light-weight stereo camera setup is used. However, also frame-to-frame stereo visual odometry (VO) approaches are known to accumulate pose estimation errors over time. Several valuable real-time capable techniques for outlier detection and drift reduction in frame-to-frame VO, for example robust relative orientation estimation using random sample consensus (RANSAC) and bundle adjustment, are available. This study addresses the problem of choosing appropriate VO components. We propose a frame-to-frame stereo VO method based on carefully selected components and parameters. This method is evaluated regarding the impact and value of different outlier detection and drift-reduction strategies, for example keyframe selection and sparse bundle adjustment (SBA), using reference benchmark data as well as own real stereo data. The experimental results demonstrate that our VO method is able to estimate quite accurate trajectories. Feature bucketing and keyframe selection are simple but effective strategies which further improve the VO results. Furthermore, introducing the stereo baseline constraint in pose graph optimization (PGO) leads to significant improvements.

  13. A new method for evaluating distance stereo acuity.

    Science.gov (United States)

    Zanoni, D; Rosenbaum, A L

    1991-01-01

    A new standardized method for evaluating distance stereo acuity has been developed, using the graphic capacity of a high-frequency microprocessor and liquid crystal binocular glasses. Images are alternately presented at a frequency of 60 cycles per second to each eye, using synchronized liquid crystal shutter glasses. The amount of disparity in the stereo patterns can be altered to allow a measurement as refined as 15 seconds of arc ("). This instrument is now commercially available as part of the Mentor B-Vat system. We evaluated distance Random Dot and Contour circle stereo acuity of 50 normal subjects using this new method and compared these results to conventional Titmus and Randot circles at near. The distance stereo acuity mean results were 139" for the Random Dot test and 41.1" for the Contour circles. The near stereo acuity results were 41.8" for the Titmus circles and 27" for the Randot circles. Statistically, the Titmus results at near can be compared to the Contour circles at distance. The distance Random Dot test results demonstrate much less stereoability than the other test. The application of these new distance stereotests will be discussed.

  14. Geometrical distortion calibration of the stereo camera for the BepiColombo mission to Mercury

    Science.gov (United States)

    Simioni, Emanuele; Da Deppo, Vania; Re, Cristina; Naletto, Giampiero; Martellato, Elena; Borrelli, Donato; Dami, Michele; Aroldi, Gianluca; Ficai Veltroni, Iacopo; Cremonese, Gabriele

    2016-07-01

    The ESA-JAXA mission BepiColombo that will be launched in 2018 is devoted to the observation of Mercury, the innermost planet of the Solar System. SIMBIOSYS is its remote sensing suite, which consists of three instruments: the High Resolution Imaging Channel (HRIC), the Visible and Infrared Hyperspectral Imager (VIHI), and the Stereo Imaging Channel (STC). The latter will provide the global three dimensional reconstruction of the Mercury surface, and it represents the first push-frame stereo camera on board of a space satellite. Based on a new telescope design, STC combines the advantages of a compact single detector camera to the convenience of a double direction acquisition system; this solution allows to minimize mass and volume performing a push-frame imaging acquisition. The shared camera sensor is divided in six portions: four are covered with suitable filters; the others, one looking forward and one backwards with respect to nadir direction, are covered with a panchromatic filter supplying stereo image pairs of the planet surface. The main STC scientific requirements are to reconstruct in 3D the Mercury surface with a vertical accuracy better than 80 m and performing a global imaging with a grid size of 65 m along-track at the periherm. Scope of this work is to present the on-ground geometric calibration pipeline for this original instrument. The selected STC off-axis configuration forced to develop a new distortion map model. Additional considerations are connected to the detector, a Si-Pin hybrid CMOS, which is characterized by a high fixed pattern noise. This had a great impact in pre-calibration phases compelling to use a not common approach to the definition of the spot centroids in the distortion calibration process. This work presents the results obtained during the calibration of STC concerning the distortion analysis for three different temperatures. These results are then used to define the corresponding distortion model of the camera.

  15. Radial Evolution of a Magnetic Cloud: MESSENGER, STEREO, and Venus Express Observations

    Science.gov (United States)

    Good, S. W.; Forsyth, R. J.; Raines, J. M.; Gershman, D. J.; Slavin, J. A.; Zurbuchen, T. H.

    2015-07-01

    The Solar Orbiter and Solar Probe Plus missions will provide observations of magnetic clouds closer to the Sun than ever before, and it will be good preparation for these missions to make full use of the most recent in situ data sets from the inner heliosphere—namely, those provided by MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) and Venus Express—for magnetic cloud studies. We present observations of the same magnetic cloud made by MESSENGER at Mercury and later by Solar TErrestrial RElations Observatory-B (STEREO-B), while the spacecraft were radially aligned in 2011 November. Few such radial observations of magnetic clouds have been previously reported. Estimates of the solar wind speed at MESSENGER are also presented, calculated through the application of a previously established technique. The cloud's flux rope has been analyzed using force-free fitting; the rope diameter increased from 0.18 to 0.41 AU (corresponding to an {r}{{H}}0.94 dependence on heliocentric distance, rH), and the axial magnetic field strength dropped from 46.0 to 8.7 nT (an {r}{{H}}-1.84 dependence) between the spacecraft, clear indications of an expanding structure. The axial magnetic flux was ˜0.50 nT AU2 at both spacecraft, suggesting that the rope underwent no significant erosion through magnetic reconnection between MESSENGER and STEREO-B. Further, we estimate the change in the cloud's angular width by assuming helicity conservation. It has also been found that the rope axis rotated by 30° between the spacecraft to lie close to the solar equatorial plane at STEREO-B. Such a rotation, if it is a common feature of coronal mass ejection propagation, would have important implications for space weather forecasting.

  16. A robust method for online stereo camera self-calibration in unmanned vehicle system

    Science.gov (United States)

    Zhao, Yu; Chihara, Nobuhiro; Guo, Tao; Kimura, Nobutaka

    2014-06-01

    Self-calibration is a fundamental technology used to estimate the relative posture of the cameras for environment recognition in unmanned system. We focused on the issue of recognition accuracy decrease caused by the vibration of platform and conducted this research to achieve on-line self-calibration using feature point's registration and robust estimation of fundamental matrix. Three key factors in this respect are needed to be improved. Firstly, the feature mismatching exists resulting in the decrease of estimation accuracy of relative posture. The second, the conventional estimation method cannot satisfy both the estimation speed and calibration accuracy at the same tame. The third, some system intrinsic noises also lead greatly to the deviation of estimation results. In order to improve the calibration accuracy, estimation speed and system robustness for the practical implementation, we discuss and analyze the algorithms to make improvements on the stereo camera system to achieve on-line self-calibration. Based on the epipolar geometry and 3D images parallax, two geometry constraints are proposed to make the corresponding feature points search performed in a small search-range resulting in the improvement of matching accuracy and searching speed. Then, two conventional estimation algorithms are analyzed and evaluated for estimation accuracy and robustness. The third, Rigorous posture calculation method is proposed with consideration of the relative posture deviation of each separated parts in the stereo camera system. Validation experiments were performed with the stereo camera mounted on the Pen-Tilt Unit for accurate rotation control and the evaluation shows that our proposed method is fast and of high accuracy with high robustness for on-line self-calibration algorithm. Thus, as the main contribution, we proposed methods to solve the on-line self-calibration fast and accurately, envision the possibility for practical implementation on unmanned system as

  17. Correspondence and coherence in science

    Directory of Open Access Journals (Sweden)

    Neal V. Dawson

    2009-03-01

    Full Text Available This paper introduces historical aspects of the concepts correspondence and coherence with emphasis on the nineteenth century when key aspects of modern science were emerging. It is not intended to be a definitive history of the concepts of correspondence and coherence as they have been used across the centuries in the field of inquiry that we now call science. Rather it is a brief history that highlights the apparent origins of the concepts and provides a discussion of how these concepts contributed to two important science related controversies. The first relates to aspects of evolution in which correspondence and coherence, as competing theories of truth, played a central role. The controversy about evolution continues into the beginning of the twenty-first century in forms that are recognizably similar to those of the middle of the nineteenth century. The second controversy relates to the etiology of blood-born infections (sepsis during childbirth (childbed fever. In addition to correspondence and coherence, the authors introduce other theories of truth and discuss an evolutionarily cogent theory of truth, the pragmatic theory of truth.

  18. Correspondence analysis of longitudinal data

    NARCIS (Netherlands)

    Van der Heijden, P.G.M.

    2005-01-01

    Correspondence analysis is an exploratory tool for the analysis of associations between categorical variables, the results of which may be displayed graphically. For longitudinal data with two time points, an analysis of the transition matrix (showing the relative frequencies for pairs of categories

  19. Computing effects for correspondence types

    DEFF Research Database (Denmark)

    Hüttel, Hans

    2010-01-01

    We show that type and effect inference is possible for a type and  effect system for authenticity using non-injective correspondences, opponent  types and a spi-calculus with symmetric encryption. We do this by a general  account of how effects can be computed given knowledge of how and where they...

  20. Correspondence analysis of longitudinal data

    NARCIS (Netherlands)

    Van der Heijden, P.G.M.|info:eu-repo/dai/nl/073087998

    2005-01-01

    Correspondence analysis is an exploratory tool for the analysis of associations between categorical variables, the results of which may be displayed graphically. For longitudinal data with two time points, an analysis of the transition matrix (showing the relative frequencies for pairs of categories

  1. Type inference for correspondence types

    DEFF Research Database (Denmark)

    Hüttel, Hans; Gordon, Andy; Hansen, Rene Rydhof

    2009-01-01

    We present a correspondence type/effect system for authenticity in a π-calculus with polarized channels, dependent pair types and effect terms and show how one may, given a process P and an a priori type environment E, generate constraints that are formulae in the Alternating Least Fixed-Point (A...

  2. Local Stereo Matching Based on Information Entropy of Image

    Science.gov (United States)

    Geng, Yingnan

    2016-09-01

    Adaptive support-window algorithm is one of the simplest local algorithms for stereo matching. An important problem for adaptive support-window algorithm is to determine the appropriate support-window size, which is always hard to do and limits the validity of adaptive support-window algorithm. An appropriate support-window size must be selected adaptively based on image features. In this paper, information entropy of image is defined for stereo matching in the RGB vector space. Based on adaptive support-window, a new support-window selection algorithm, which uses information entropy of image to quantify image features such as illumination color and number of object contained in an image, is proposed. Experimental results evaluated on the Middlebury stereo benchmark show that our algorithm outperforms the conventional adaptive support-window algorithms.

  3. Characteristics of stereo images from detectors in focal plane array.

    Science.gov (United States)

    Son, Jung-Young; Yeom, Seokwon; Chun, Joo-Hwan; Guschin, Vladmir P; Lee, Dong-Su

    2011-07-01

    The equivalent ray geometry of two horizontally aligned detectors at the focal plane of the main antenna in a millimeter wave imaging system is analyzed to reveal the reason why the images from the detectors are fused as an image with a depth sense. Scanning the main antenna in both horizontal and vertical directions makes each detector perform as a camera, and the two detectors can work like a stereo camera in the millimeter wave range. However, the stereo camera geometry is different from that of the stereo camera used in the visual spectral range because the detectors' viewing directions are diverging to each other and they are a certain distance apart. The depth sense is mainly induced by the distance between detectors. The images obtained from the detectors in the millimeter imaging system are perceived with a good depth sense. The disparities responsible for the depth sense are identified in the images.

  4. Interaction of algorithm and implementation for analog VLSI stereo vision

    Science.gov (United States)

    Hakkarainen, J. M.; Little, James J.; Lee, Hae-Seung; Wyatt, John L., Jr.

    1991-07-01

    Design of a high-speed stereo vision system in analog VLSI technology is reported. The goal is to determine how the advantages of analog VLSI--small area, high speed, and low power-- can be exploited, and how the effects of its principal disadvantages--limited accuracy, inflexibility, and lack of storage capacity--can be minimized. Three stereo algorithms are considered, and a simulation study is presented to examine details of the interaction between algorithm and analog VLSI implementation. The Marr-Poggio-Drumheller algorithm is shown to be best suited for analog VLSI implementation. A CCD/CMOS stereo system implementation is proposed, capable of operation at 6000 image frame pairs per second for 48 X 48 images, and faster than frame rate operation on 256 X 256 binocular image pairs.

  5. Multiple footprint stereo algorithms for 3D display content generation

    Science.gov (United States)

    Boughorbel, Faysal

    2007-02-01

    This research focuses on the conversion of stereoscopic video material into an image + depth format which is suitable for rendering on the multiview auto-stereoscopic displays of Philips. The recent interest shown in the movie industry for 3D significantly increased the availability of stereo material. In this context the conversion from stereo to the input formats of 3D displays becomes an important task. In this paper we present a stereo algorithm that uses multiple footprints generating several depth candidates for each image pixel. We characterize the various matching windows and we devise a robust strategy for extracting high quality estimates from the resulting depth candidates. The proposed algorithm is based on a surface filtering method that employs simultaneously the available depth estimates in a small local neighborhood while ensuring correct depth discontinuities by the inclusion of image constraints. The resulting highquality image-aligned depth maps proved an excellent match with our 3D displays.

  6. PRISM: A Practical Mealtime Imaging Stereo Matcher

    Science.gov (United States)

    Nishihara, H. K.

    1984-02-01

    A fast stereo-matching algorithm designed to operate in the presence of noise is described. The algorithm has its roots in the zero-crossing theory of Marr and Poggio but does not explicitly match zero-crossing contours. While these contours are for the most part stably tied to fixed surface locations, some fraction is always perturbed significantly by system noise. Zero-crossing contour based matching algorithms tend to I- very sensitive to these local distortions and ar, prevented from operating well on signals with moderate noise levels even though a substantial amount of information may still be present. The dual representation ¬â€?regions of constant sign in the V2G convolution persist much further into the noise than does the local geometry of the zero-crossing contours that delimit them. The PRISM system was designed to test this approach. The initial design task of the implementation has been to rapidly detect obstacles in a robotics work space and determine their rough extents and heights. In this case speed and reliability are important but precision is less critical. The system uses a pair of inexpensive vidicon cameras mounted above the workspace of a PUMA robot manipulator. The digitized video signals are fed to a high speed digital convolver that applies a 322 VG operator to the images at a 106 pixel per second rate. Matching is accomplished in software on a lisp machine with individual near/far tests taking less than i3luth of a second. A 36 by 26 matrix of absolute height measurements - in mm - over a 100 pixel disparity range is produced in 30 seconds from image acquisition to final output. Three scales of resolution are used in a coarse guides fine search. Acknowledgment: This report describes research done at the Artificial Intelligence Laboratory of the Massachusetts Institute of 'Technology Support for the laboratory's artificial intelligence research is provided in part by the Advanced Research Projects Agency of the Department of Defense

  7. Multi-scale measures of rugosity, slope and aspect from benthic stereo image reconstructions.

    Directory of Open Access Journals (Sweden)

    Ariell Friedman

    Full Text Available This paper demonstrates how multi-scale measures of rugosity, slope and aspect can be derived from fine-scale bathymetric reconstructions created from geo-referenced stereo imagery. We generate three-dimensional reconstructions over large spatial scales using data collected by Autonomous Underwater Vehicles (AUVs, Remotely Operated Vehicles (ROVs, manned submersibles and diver-held imaging systems. We propose a new method for calculating rugosity in a Delaunay triangulated surface mesh by projecting areas onto the plane of best fit using Principal Component Analysis (PCA. Slope and aspect can be calculated with very little extra effort, and fitting a plane serves to decouple rugosity from slope. We compare the results of the virtual terrain complexity calculations with experimental results using conventional in-situ measurement methods. We show that performing calculations over a digital terrain reconstruction is more flexible, robust and easily repeatable. In addition, the method is non-contact and provides much less environmental impact compared to traditional survey techniques. For diver-based surveys, the time underwater needed to collect rugosity data is significantly reduced and, being a technique based on images, it is possible to use robotic platforms that can operate beyond diver depths. Measurements can be calculated exhaustively at multiple scales for surveys with tens of thousands of images covering thousands of square metres. The technique is demonstrated on data gathered by a diver-rig and an AUV, on small single-transect surveys and on a larger, dense survey that covers over [Formula: see text]. Stereo images provide 3D structure as well as visual appearance, which could potentially feed into automated classification techniques. Our multi-scale rugosity, slope and aspect measures have already been adopted in a number of marine science studies. This paper presents a detailed description of the method and thoroughly validates it

  8. Onboard low-complexity compression of solar stereo images.

    Science.gov (United States)

    Wang, Shuang; Cui, Lijuan; Cheng, Samuel; Stanković, Lina; Stanković, Vladimir

    2012-06-01

    We propose an adaptive distributed compression solution using particle filtering that tracks correlation, as well as performing disparity estimation, at the decoder side. The proposed algorithm is tested on the stereo solar images captured by the twin satellites system of NASA's Solar TErrestrial RElations Observatory (STEREO) project. Our experimental results show improved compression performance w.r.t. to a benchmark compression scheme, accurate correlation estimation by our proposed particle-based belief propagation algorithm, and significant peak signal-to-noise ratio improvement over traditional separate bit-plane decoding without dynamic correlation and disparity estimation.

  9. Hybrid Collaborative Stereo Vision System for Mobile Robots Formation

    Directory of Open Access Journals (Sweden)

    Flavio Roberti

    2010-02-01

    Full Text Available This paper presents the use of a hybrid collaborative stereo vision system (3D-distributed visual sensing using different kinds of vision cameras for the autonomous navigation of a wheeled robot team. It is proposed a triangulation-based method for the 3D-posture computation of an unknown object by considering the collaborative hybrid stereo vision system, and this way to steer the robot team to a desired position relative to such object while maintaining a desired robot formation. Experimental results with real mobile robots are included to validate the proposed vision system.

  10. Computing effects for correspondence types

    OpenAIRE

    2010-01-01

    We show that type and effect inference is possible for a type and  effect system for authenticity using non-injective correspondences, opponent  types and a spi-calculus with symmetric encryption. We do this by a general  account of how effects can be computed given knowledge of how and where they  appear in type judgments. 

  11. High-resolution photogrammetric surface extraction over glaciated regions from WorldView stereo pairs

    Science.gov (United States)

    Noh, M.; Howat, I. M.; Morin, P. J.; Porter, C. C.

    2013-12-01

    The monitoring of surface change in glaciated regions such as Alaska, Greenland and Antarctica is an important pursuit in climate-related Earth Science. Repeat Digital Elevation Models (DEM) created by photogrammetric surface extraction from a time-series of stereo pairs provide an efficient and low cost means for analyzing surface change over large, remote areas. Stereo-photogrammetric DEM extraction over glaciated regions is challenging due to typically low-contrast surfaces such as ice, snow, mountain shadows and steep slopes, resulting in large feature search areas and matching failures. A method for reducing the feature search area is critical for successful and efficient DEM extraction in this terrain. The SETSM (Surface Extraction with TIN-based Search-space Minimization) algorithm is developed for overcoming these problems and performs surface extraction automatically, without any user-defined or a-priori information, such as seed DEMs, using only the sensor Rational Polynomial Coefficients (RPCs) for geometric constraints. Rotation-invariant, multi-patch Normalized Cross Correlation (NCC) is used as its basic similarity measurement. SETSM constructs a TIN (Triangular Irregular Network) in the object-space domain in order to minimize the necessary search space. It employs a pyramiding strategy that uses iteratively finer resolution TIN's to minimize the search space and uses a vertical line locus to provide precise geometric constraints for reducing the search area. As a major benefit, SETSM relatively adjusts the Rational Function Model (RFM) between stereo pairs to reduce the offset between corresponding points projected by the vertical line locus caused by RPC errors, dramatically reducing the number of matching failures. In SETSM, this offset is iteratively removed with a parabolic adjustment of the NCC solution. As a demonstration, Worldview stereo pairs for a variety of test areas in Alaska, Greenland and Antarctica are selected for creating 2m grid

  12. Real-time surface reconstruction from stereo endoscopic images for intraoperative registration

    Science.gov (United States)

    Röhl, S.; Bodenstedt, S.; Suwelack, S.; Kenngott, H.; Mueller-Stich, B. P.; Dillmann, R.; Speidel, S.

    2011-03-01

    Minimally invasive surgery is a medically complex discipline that can heavily benefit from computer assistance. One way to assist the surgeon is to blend in useful information about the intervention into the surgical view using Augmented Reality. This information can be obtained during preoperative planning and integrated into a patient-tailored model of the intervention. Due to soft tissue deformation, intraoperative sensor data such as endoscopic images has to be acquired and non-rigidly registered with the preoperative model to adapt it to local changes. Here, we focus on a procedure that reconstructs the organ surface from stereo endoscopic images with millimeter accuracy in real-time. It deals with stereo camera calibration, pixel-based correspondence analysis, 3D reconstruction and point cloud meshing. Accuracy, robustness and speed are evaluated with images from a test setting as well as intraoperative images. We also present a workflow where the reconstructed surface model is registered with a preoperative model using an optical tracking system. As preliminary result, we show an initial overlay between an intraoperative and a preoperative surface model that leads to a successful rigid registration between these two models.

  13. Error analysis in a stereo vision-based pedestrian detection sensor for collision avoidance applications.

    Science.gov (United States)

    Llorca, David F; Sotelo, Miguel A; Parra, Ignacio; Ocaña, Manuel; Bergasa, Luis M

    2010-01-01

    This paper presents an analytical study of the depth estimation error of a stereo vision-based pedestrian detection sensor for automotive applications such as pedestrian collision avoidance and/or mitigation. The sensor comprises two synchronized and calibrated low-cost cameras. Pedestrians are detected by combining a 3D clustering method with Support Vector Machine-based (SVM) classification. The influence of the sensor parameters in the stereo quantization errors is analyzed in detail providing a point of reference for choosing the sensor setup according to the application requirements. The sensor is then validated in real experiments. Collision avoidance maneuvers by steering are carried out by manual driving. A real time kinematic differential global positioning system (RTK-DGPS) is used to provide ground truth data corresponding to both the pedestrian and the host vehicle locations. The performed field test provided encouraging results and proved the validity of the proposed sensor for being used in the automotive sector towards applications such as autonomous pedestrian collision avoidance.

  14. Error Analysis in a Stereo Vision-Based Pedestrian Detection Sensor for Collision Avoidance Applications

    Directory of Open Access Journals (Sweden)

    David F. Llorca

    2010-04-01

    Full Text Available This paper presents an analytical study of the depth estimation error of a stereo vision-based pedestrian detection sensor for automotive applications such as pedestrian collision avoidance and/or mitigation. The sensor comprises two synchronized and calibrated low-cost cameras. Pedestrians are detected by combining a 3D clustering method with Support Vector Machine-based (SVM classification. The influence of the sensor parameters in the stereo quantization errors is analyzed in detail providing a point of reference for choosing the sensor setup according to the application requirements. The sensor is then validated in real experiments. Collision avoidance maneuvers by steering are carried out by manual driving. A real time kinematic differential global positioning system (RTK-DGPS is used to provide ground truth data corresponding to both the pedestrian and the host vehicle locations. The performed field test provided encouraging results and proved the validity of the proposed sensor for being used in the automotive sector towards applications such as autonomous pedestrian collision avoidance.

  15. Stereo vision for planetary rovers - Stochastic modeling to near real-time implementation

    Science.gov (United States)

    Matthies, Larry

    1991-01-01

    JPL has achieved the first autonomous cross-country robotic traverses to use stereo vision, with all computing onboard the vehicle. This paper describes the stereo vision system, including the underlying statistical model and the details of the implementation. It is argued that the overall approach provides a unifying paradigm for practical domain-independent stereo ranging.

  16. Automated segmentation of the optic disc from stereo color photographs using physiologically plausible features

    NARCIS (Netherlands)

    Abramoff, M.D.; Alward, W.L.M.; Greenlee, E.C.; Shuba, L.; Kim, Chan Y.; Fingert, J.H.; Kwon, Y.H.

    2007-01-01

    PURPOSE. To evaluate a novel automated segmentation algorithm for cup-to-disc segmentation from stereo color photographs of patients with glaucoma for the measurement of glaucoma progression. METHODS. Stereo color photographs of the optic disc were obtained by using a fixed stereo-base fundus

  17. 基于PLC控制立体车库的设计%The design of the stereo garage based on PLC control

    Institute of Scientific and Technical Information of China (English)

    张小娟

    2014-01-01

    The stereo garage has become the important way and the development direction to solve the problem of parking difficulty. It takes three-layer and nine-location of the lifting and moving stereo garage for example,introducing its working principle and the components of the control system,focusing on the design of the control system by PLC as the core,and the corresponding program design,the stereo garage automatic control has achieved. In order to slow down pressure of the parking space,the stereo garage has been Established. The Paper introduced some safety technique which was used in the up-down and translation stereo garage. This can ensure absolute safety for Car and make the whole stereo garage safety and running smooth.%立体车库已经成为解决停车难问题的重要途径和发展方向。以三层九位的升降横移式立体车库为例,介绍了其工作原理和控制系统的组成,重点叙述了以 PLC为核心的控制系统的设计,以及相应的程序设计,实现了立体车库的自动控制。立体车库的建立减缓了车辆的增多给停车空间的需求带来的压力。本文在升降横移式立体车库中使用了一些必要的安全技术,这样保证了车辆的绝对安全,使得整个车库可以安全平稳的运行。

  18. Nucleosynthesis in Hot and Dense Media

    CERN Document Server

    Masood, Samina S

    2014-01-01

    We study the finite temperature and density effects on beta decay rates to compute their contributions to nucleosynthesis. QED type corrections to beta decay from the hot and dense background are estimated in terms of the statistical corrections to the self-mass of an electron. For this purpose, we re-examine the hot and dense background contributions to the electron mass and compute its effect to the beta decay rate, helium yield, energy density of the universe as well as the change in neutrino temperature from the first order contribution to the self-mass of electrons during these processes. We explicitly show that the thermal contribution to the helium abundance at T = m of a cooling universe 0.045 % is higher than the corresponding contribution to helium abundance of a heating universe 0.031% due to the existence of hot fermions before the beginning of nucleosynthesis and their absence after the nucleosynthesis, in the early universe. Thermal contribution to helium abundance was a simple quadratic functio...

  19. Constructing dense genetic linkage maps

    NARCIS (Netherlands)

    Jansen, J.; Jong, de A.G.; Ooijen, van J.W.

    2001-01-01

    This paper describes a novel combination of techniques for the construction of dense genetic linkage maps. The construction of such maps is hampered by the occurrence of even small proportions of typing errors. Simulated annealing is used to obtain the best map according to the optimality criterion:

  20. Method for dense packing discovery.

    Science.gov (United States)

    Kallus, Yoav; Elser, Veit; Gravel, Simon

    2010-11-01

    The problem of packing a system of particles as densely as possible is foundational in the field of discrete geometry and is a powerful model in the material and biological sciences. As packing problems retreat from the reach of solution by analytic constructions, the importance of an efficient numerical method for conducting de novo (from-scratch) searches for dense packings becomes crucial. In this paper, we use the divide and concur framework to develop a general search method for the solution of periodic constraint problems, and we apply it to the discovery of dense periodic packings. An important feature of the method is the integration of the unit-cell parameters with the other packing variables in the definition of the configuration space. The method we present led to previously reported improvements in the densest-known tetrahedron packing. Here, we use the method to reproduce the densest-known lattice sphere packings and the best-known lattice kissing arrangements in up to 14 and 11 dimensions, respectively, providing numerical evidence for their optimality. For nonspherical particles, we report a dense packing of regular four-dimensional simplices with density ϕ=128/219≈0.5845 and with a similar structure to the densest-known tetrahedron packing.

  1. Unconditional Continuous Variable Dense Coding

    CERN Document Server

    Ralph, T C

    2002-01-01

    We investigate the conditions under which unconditional dense coding can be achieved using continuous variable entanglement. We consider the effect of entanglement impurity and detector efficiency and discuss experimental verification. We conclude that the requirements for a strong demonstration are not as stringent as previously thought and are within the reach of present technology.

  2. Sound scattering in dense granular media

    Institute of Scientific and Technical Information of China (English)

    JIA XiaoPing; LAURENT J; KHIDAS Y; LANGLOIS V

    2009-01-01

    The sound propagation in a dense granular medium is basically characterized by the ratio of wave-length to the grain size. Two types of wave transport are distinguished: one corresponds to coherent waves in the long wavelength limit, the other to short-wavelength scattered waves by the inhomoge-neous contact force networks. These multiply scattered elastic waves are shown to exhibit a diffusive characteristics of transport over long distances of propagation. Determination of the transport mean free path l* and the inelastic absorption (Q~(-1)) allows the inference of the structural properties of the material such as the heterogeneity and internal dissipation. The relevance of our experiments for seismological applications is discussed. Moreover, we apply the correlation technique of the configu-ration-specific sound scattering to monitoring the dynamic behaviour of the granular medium (irre-versible rearrangements) under strong vibration, shearing and thermal cycling, respectively.

  3. Einstein Gravity-Supergravity Correspondence

    CERN Document Server

    Chen, C M; Sharakin, S A; Chen, Chiang-Mei; Gal'tsov, Dmitri V.; Sharakin, Sergei A.

    1999-01-01

    A correspondence between the three-block truncated 11D supergravity and the 8D pure Einstein gravity with two commuting Killing symmetries is discussed. The Kaluza-Klein two-forms of the 6D theory obtained after dimensional reduction along the Killing orbits generate the four-form field of supergravity via an inverse dualization. Thus any solution to the vacuum Einstein equations in eight dimensions depending on six coordinates have 11D-supergravity counterparts with the non-trivial four-form field. Using this proposed duality we derive a new dyon solution of 11D supergravity describing the M2 and M5-branes intersecting at a point.

  4. Quivers, Invariants and Quotient Correspondence

    CERN Document Server

    Hu, Yi

    2010-01-01

    This paper studies the geometric and algebraic aspects of the moduli spaces of quivers of fence type. We first provide two quotient presentations of the quiver varieties and interpret their equivalence as a generalized Gelfand-MacPherson correspondence. Next, we introduce parabolic quivers and extend the above from the actions of reductive groups to the actions of parabolic subgroups. Interestingly, the above geometry finds its natural counterparts in the representation theory as the branching rules and transfer principle in the context of the reciprocity algebra. The last half of the paper establishes this connection.

  5. Distributed quantum dense coding with two receivers in noisy environments

    Science.gov (United States)

    Das, Tamoghna; Prabhu, R.; SenDe, Aditi; Sen, Ujjwal

    2015-11-01

    We investigate the effect of noisy channels in a classical information transfer through a multipartite state which acts as a substrate for the distributed quantum dense coding protocol between several senders and two receivers. The situation is qualitatively different from the case with one or more senders and a single receiver. We obtain an upper bound on the multipartite capacity which is tightened in the case of the covariant noisy channel. We also establish a relation between the genuine multipartite entanglement of the shared state and the capacity of distributed dense coding using that state, both in the noiseless and the noisy scenarios. Specifically, we find that, in the case of multiple senders and two receivers, the corresponding generalized Greenberger-Horne-Zeilinger states possess higher dense coding capacities as compared to a significant fraction of pure states having the same multipartite entanglement.

  6. Stereo Calibration and Rectification for Omnidirectional Multi-camera Systems

    Directory of Open Access Journals (Sweden)

    Yanchang Wang

    2012-10-01

    Full Text Available Stereo vision has been studied for decades as a fundamental problem in the field of computer vision. In recent years, computer vision and image processing with a large field of view, especially using omnidirectional vision and panoramic images, has been receiving increasing attention. An important problem for stereo vision is calibration. Although various kinds of calibration methods for omnidirectional cameras are proposed, most of them are limited to calibrate catadioptric cameras or fish‐eye cameras and cannot be applied directly to multi‐camera systems. In this work, we propose an easy calibration method with closed‐form initialization and iterative optimization for omnidirectional multi‐camera systems. The method only requires image pairs of the 2D target plane in a few different views. A method based on the spherical camera model is also proposed for rectifying omnidirectional stereo pairs. Using real data captured by Ladybug3, we carry out some experiments, including stereo calibration, rectification and 3D reconstruction. Statistical analyses and comparisons of the experimental results are also presented. As the experimental results show, the calibration results are precise and the effect of rectification is promising.

  7. Stereo PIV Experiments on Horizontal Axis Wind Turbine Rotor Model

    NARCIS (Netherlands)

    Akay, B.; Micallef, D.; Ferreira, C.S.; Van Bussel, G.J.W.

    2011-01-01

    This paper sets out to describe the measurements and computations to construct three components of velocity field around the blade. The primary aim of the measurements was to gain insight into the physics of the flow field produced by a horizontal axis wind turbine-HAWT blade. Stereo Particle Image

  8. Stereo Matching Algorithm Based on 2D Delaunay Triangulation

    Directory of Open Access Journals (Sweden)

    Xue-he Zhang

    2015-01-01

    Full Text Available To fulfill the applications on robot vision, the commonly used stereo matching method for depth estimation is supposed to be efficient in terms of running speed and disparity accuracy. Based on this requirement, Delaunay-based stereo matching method is proposed to achieve the aforementioned standards in this paper. First, a Canny edge operator is used to detect the edge points of an image as supporting points. Those points are then processed using a Delaunay triangulation algorithm to divide the whole image into a series of linked triangular facets. A proposed module composed of these facets performs a rude estimation of image disparity. According to the triangular property of shared vertices, the estimated disparity is then refined to generate the disparity map. The method is tested on Middlebury stereo pairs. The running time of the proposed method is about 1 s and the matching accuracy is 93%. Experimental results show that the proposed method improves both running speed and disparity accuracy, which forms a steady foundation and good application prospect for a robot’s path planning system with stereo camera devices.

  9. Stereo matching based on census transformation of image gradients

    Science.gov (United States)

    Stentoumis, C.; Grammatikopoulos, L.; Kalisperakis, I.; Karras, G.; Petsa, E.

    2015-05-01

    Although multiple-view matching provides certain significant advantages regarding accuracy, occlusion handling and radiometric fidelity, stereo-matching remains indispensable for a variety of applications; these involve cases when image acquisition requires fixed geometry and limited number of images or speed. Such instances include robotics, autonomous navigation, reconstruction from a limited number of aerial/satellite images, industrial inspection and augmented reality through smart-phones. As a consequence, stereo-matching is a continuously evolving research field with growing variety of applicable scenarios. In this work a novel multi-purpose cost for stereo-matching is proposed, based on census transformation on image gradients and evaluated within a local matching scheme. It is demonstrated that when the census transformation is applied on gradients the invariance of the cost function to changes in illumination (non-linear) is significantly strengthened. The calculated cost values are aggregated through adaptive support regions, based both on cross-skeletons and basic rectangular windows. The matching algorithm is tuned for the parameters in each case. The described matching cost has been evaluated on the Middlebury stereo-vision 2006 datasets, which include changes in illumination and exposure. The tests verify that the census transformation on image gradients indeed results in a more robust cost function, regardless of aggregation strategy.

  10. VPython: Python plus Animations in Stereo 3D

    Science.gov (United States)

    Sherwood, Bruce

    2004-03-01

    Python is a modern object-oriented programming language. VPython (http://vpython.org) is a combination of Python (http://python.org), the Numeric module from LLNL (http://www.pfdubois.com/numpy), and the Visual module created by David Scherer, all of which have been under continuous development as open source projects. VPython makes it easy to write programs that generate real-time, navigable 3D animations. The Visual module includes a set of 3D objects (sphere, cylinder, arrow, etc.), tools for creating other shapes, and support for vector algebra. The 3D renderer runs in a parallel thread, and animations are produced as a side effect of computations, freeing the programmer to concentrate on the physics. Applications include educational and research visualization. In the Fall of 2003 Hugh Fisher at the Australian National University, John Zelle at Wartburg College, and I contributed to a new stereo capability of VPython. By adding a single statement to an existing VPython program, animations can be viewed in true stereo 3D. One can choose several modes: active shutter glasses, passive polarized glasses, or colored glasses (e.g. red-cyan). The talk will demonstrate the new stereo capability and discuss the pros and cons of various schemes for display of stereo 3D for a large audience. Supported in part by NSF grant DUE-0237132.

  11. People counting with stereo cameras: two template-based solutions

    NARCIS (Netherlands)

    van Oosterhout, T.; Kröse, B.; Englebienne, G.; Csurka, G.; Braz, J.

    2012-01-01

    People counting is a challenging task with many applications. We propose a method with a fixed stereo camera that is based on projecting a template onto the depth image. The method was tested on a challenging outdoor dataset with good results and runs in real time.

  12. A stereo camera system for autonomous maritime navigation (AMN) vehicles

    Science.gov (United States)

    Zhang, Weihong; Zhuang, Ping; Elkins, Les; Simon, Rick; Gore, David; Cogar, Jeff; Hildebrand, Kevin; Crawford, Steve; Fuller, Joe

    2009-05-01

    Spatial Integrated System (SIS), Rockville, Maryland, in collaboration with NSWC Combatant Craft Division (NSWCCD), is applying 3D imaging technology, artificial intelligence, sensor fusion, behaviors-based control, and system integration to a prototype 40 foot, high performance Research and Development Unmanned Surface Vehicle (USV). This paper focus on the developments of the stereo camera system in the USV navigation that currently consists of two high-resolution cameras and will incorporate an array of cameras in the near future. The objectives of the camera system are to re-construct 3D objects and detect them in the sea water surface. The paper reviews two critical technological components, namely camera calibration and stereo matching. In stereo matching, a comprehensive study is presented to compare the algorithmic performances resulted from the various information sources (intensity, RGB values, Gaussian gradients and Gaussian Laplacians), patching schemas (single windows, and multiple windows with same/different centers), and correlation metrics (convolution, absolute difference, and histogram). To enhance system performance, a sub-pixel edge detection technique has been introduced to address the precision requirement and a noise removal post-processing step added to eliminate noisy points from the reconstructed 3D point clouds. Finally, experimental results are reported to demonstrate the performance of the stereo camera system.

  13. Virtual Reality, 3D Stereo Visualization, and Applications in Robotics

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2006-01-01

    The use of 3D stereoscopic visualization may provide a user with higher comprehension of remote environments in tele-operation when compared to 2D viewing. Works in the literature have demonstrated how stereo vision contributes to improve perception of some depth cues often for abstract tasks...

  14. Stereo PIV Experiments on Horizontal Axis Wind Turbine Rotor Model

    NARCIS (Netherlands)

    Akay, B.; Micallef, D.; Ferreira, C.S.; Van Bussel, G.J.W.

    2011-01-01

    This paper sets out to describe the measurements and computations to construct three components of velocity field around the blade. The primary aim of the measurements was to gain insight into the physics of the flow field produced by a horizontal axis wind turbine-HAWT blade. Stereo Particle Image

  15. Stereo Orthogonal Axonometric Perspective for the Teaching of Descriptive Geometry

    Science.gov (United States)

    Méxas, José Geraldo Franco; Guedes, Karla Bastos; Tavares, Ronaldo da Silva

    2015-01-01

    Purpose: The purpose of this paper is to present the development of a software for stereo visualization of geometric solids, applied to the teaching/learning of Descriptive Geometry. Design/methodology/approach: The paper presents the traditional method commonly used in computer graphic stereoscopic vision (implemented in C language) and the…

  16. [EEG technician-nurse collaboration during stereo-electroencephalography].

    Science.gov (United States)

    Jomard, Caroline; Benghezal, Mouna; Cheramy, Isabelle; De Beaumont, Ségolène

    2017-01-01

    Drug-resistant epilepsy has significant repercussions on the daily life of children. Surgery may represent a hope. The nurse and the electroencephalogram technician carry out important teamwork during pre-surgical assessment tests and notably the stereo-electroencephalography. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Solving the uncalibrated photometric stereo problem using total variation

    DEFF Research Database (Denmark)

    Quéau, Yvain; Lauze, Francois Bernard; Durou, Jean-Denis

    2013-01-01

    In this paper we propose a new method to solve the problem of uncalibrated photometric stereo, making very weak assumptions on the properties of the scene to be reconstructed. Our goal is to solve the generalized bas-relief ambiguity (GBR) by performing a total variation regularization of both th...

  18. Stereo Orthogonal Axonometric Perspective for the Teaching of Descriptive Geometry

    Science.gov (United States)

    Méxas, José Geraldo Franco; Guedes, Karla Bastos; Tavares, Ronaldo da Silva

    2015-01-01

    Purpose: The purpose of this paper is to present the development of a software for stereo visualization of geometric solids, applied to the teaching/learning of Descriptive Geometry. Design/methodology/approach: The paper presents the traditional method commonly used in computer graphic stereoscopic vision (implemented in C language) and the…

  19. Venus - Stereo Image Pair of Crater Geopert-Meyer

    Science.gov (United States)

    1993-01-01

    During the third global cycle of Magellan's radar mapping mission, images were obtained at viewing angles that were slightly different than those used in the first two cycles. This strategy was designed to produce stereo image pairs, which take advantage of distortions induced by the different views to provide details of the surface topography. This is a stereo image pair of crater Geopert-Meyer, named for the 20th Century Polish physicist and Nobel laureate (60 degrees north latitude, 26.5 degrees east longitude). The crater, 35 kilometers (22 miles) in diameter, lies above an escarpment at the edge of a ridge belt in southern Ishtar Terra. West of the crater the scarp has more than one kilometer (0.6 mile) of relief. Perception of relief may be obtained with stereo glasses or a stereoscope. Some individuals may be able to fuse the images without the aid of those devices. The radar illumination for both images is from the west, or left side of the scene. Incidence angles are: (Cycle 1 (left) 28 degrees, Cycle 3 (right) 15 degrees from vertical. Analysis of stereo image pairs allows planetary scientists to resolve details of topographic relationships on Venusian craters, volcanoes, mountain belts and fault zones. The spatial resolution of this topographic information is approximately ten times better than that obtained by Magellan's altimetry experiment.

  20. A Stereo Music Preprocessing Scheme for Cochlear Implant Users.

    Science.gov (United States)

    Buyens, Wim; van Dijk, Bas; Wouters, Jan; Moonen, Marc

    2015-10-01

    Listening to music is still one of the more challenging aspects of using a cochlear implant (CI) for most users. Simple musical structures, a clear rhythm/beat, and lyrics that are easy to follow are among the top factors contributing to music appreciation for CI users. Modifying the audio mix of complex music potentially improves music enjoyment in CI users. A stereo music preprocessing scheme is described in which vocals, drums, and bass are emphasized based on the representation of the harmonic and the percussive components in the input spectrogram, combined with the spatial allocation of instruments in typical stereo recordings. The scheme is assessed with postlingually deafened CI subjects (N = 7) using pop/rock music excerpts with different complexity levels. The scheme is capable of modifying relative instrument level settings, with the aim of improving music appreciation in CI users, and allows individual preference adjustments. The assessment with CI subjects confirms the preference for more emphasis on vocals, drums, and bass as offered by the preprocessing scheme, especially for songs with higher complexity. The stereo music preprocessing scheme has the potential to improve music enjoyment in CI users by modifying the audio mix in widespread (stereo) music recordings. Since music enjoyment in CI users is generally poor, this scheme can assist the music listening experience of CI users as a training or rehabilitation tool.

  1. Stereo based Obstacle Detection with Uncertainty in Rough Terrain

    NARCIS (Netherlands)

    Mark, W. van der; Heuvel, J.C. van den; Groen, F.C.A.

    2007-01-01

    Autonomous robot vehicles that operate in offroad terrain should avoid obstacle hazards. In this paper we present a stereo vision based method that is able to cluster reconstructed terrain points into obstacles by evaluating their relative angles and distances. In our approach, constraints are enfor

  2. MARVEL: A System for Recognizing World Locations with Stereo Vision

    Science.gov (United States)

    1990-05-01

    Baxandall 1983]) to plan their daily commutes or vacation excursions. 147 148 CHAPTER 9. LOCATION RECOGNITION AND THE WORFLD MODEL 9.1 Introduction...Inc. 1982. Baxandall , L. World Guide to Nude Beaches and Recreation. New York: Harmony Books. 1983. Binford, T. 0. Survey of stereo mapping systems

  3. PEOPLE COUNTING WITH STEREO CAMERAS: Two Template-based Solutions

    NARCIS (Netherlands)

    Van Oosterhout, Tim; Kröse, Ben; Englebienne, Gwenn

    2012-01-01

    People counting is a challenging task with many applications. We propose a method with a fixed stereo camera that is based on projecting a template onto the depth image. The method was tested on a challenging outdoor dataset with good results and runs in real time.

  4. Real-time Loudspeaker Distance Estimation with Stereo Audio

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Gaubitch, Nikolay; Heusdens, Richard

    2015-01-01

    . In this paper, we propose to use the desired audio signal instead. Specifically, we treat the case of estimating the distance between two loudspeakers playing back a stereo music or speech signal. In this connection, we develop a real-time maximum likelihood estimator and demonstrate that it has a variance...

  5. Processing Earth Observing images with Ames Stereo Pipeline

    Science.gov (United States)

    Beyer, R. A.; Moratto, Z. M.; Alexandrov, O.; Fong, T.; Shean, D. E.; Smith, B. E.

    2013-12-01

    ICESat with its GLAS instrument provided valuable elevation measurements of glaciers. The loss of this spacecraft caused a demand for alternative elevation sources. In response to that, we have improved our Ames Stereo Pipeline (ASP) software (version 2.1+) to ingest satellite imagery from Earth satellite sources in addition to its support of planetary missions. This enables the open source community a free method to generate digital elevation models (DEM) from Digital Globe stereo imagery and alternatively other cameras using RPC camera models. Here we present details of the software. ASP is a collection of utilities written in C++ and Python that implement stereogrammetry. It contains utilities to manipulate DEMs, project imagery, create KML image quad-trees, and perform simplistic 3D rendering. However its primary application is the creation of DEMs. This is achieved by matching every pixel between the images of a stereo observation via a hierarchical coarse-to-fine template matching method. Matched pixels between images represent a single feature that is triangulated using each image's camera model. The collection of triangulated features represents a point cloud that is then grid resampled to create a DEM. In order for ASP to match pixels/features between images, it requires a search range defined in pixel units. Total processing time is proportional to the area of the first image being matched multiplied by the area of the search range. An incorrect search range for ASP causes repeated false positive matches at each level of the image pyramid and causes excessive processing times with no valid DEM output. Therefore our system contains automatic methods for deducing what the correct search range should be. In addition, we provide options for reducing the overall search range by applying affine epipolar rectification, homography transform, or by map projecting against a prior existing low resolution DEM. Depending on the size of the images, parallax, and image

  6. New Views of the Sun: STEREO and Hinode

    Science.gov (United States)

    Luhmann, Janet G.; Tsuneta, Saku; Bougeret, J.-L.; Galvin, Antoinette; Howard, R. A.; Kaiser, Michael; Thompson, W. T.

    The twin-spacecraft STEREO mission has now been in orbit for 1.5 years. Although the main scientific objective of STEREO is the origin and evolution of Coronal Mass Ejections (CMEs) and their heliospheric consequences, the slow decline of the previous solar cycle has provided an extraordinary opportunity for close scrutiny of the quiet corona and solar wind, including suprathermal and energetic particles. However, STEREO has also captured a few late cycle CMEs that have given us a taste of the observations and analyses to come. Images from the SECCHI investigation afforded by STEREO's separated perspectives and the heliospheric imager have already allowed us to visibly witness the origins of the slow solar wind and the Sun-to-1 AU transit of ICMEs. The SWAVES investigation has monitored the transit of interplanetary shocks in 3D while the PLASTIC and IMPACT in-situ measurements provide the 'ground truth' of what is remotely sensed. New prospects for space weather forecasting have been demonstrated with the STEREO behind spacecraft, a successful proof-of-concept test for future space weather mission designs. The data sets for the STEREO investigations are openly available through a STEREO Science Center web interface that also provides supporting information for potential users from all communities. Comet observers and astronomers, interplanetary dust researchers and planetary scientists have already made use of this resource. The potential for detailed Sun-to-Earth CME/ICME interpretations with sophisticated modeling efforts are an upcoming STEREO-Hinode partnering activity whose success we can only anticipate at this time. Since its launch in September 2006, Hinode has sent back solar images of unprecedented clarity every day. The primary purpose of this mission is a systems approach to understanding the generation, transport and ultimate dissipation of solar magnetic fields with a well-coordinated set of advanced telescopes. Hinode is equipped with three

  7. Warm Dense Matter: An Overview

    Energy Technology Data Exchange (ETDEWEB)

    Kalantar, D H; Lee, R W; Molitoris, J D

    2004-04-21

    This document provides a summary of the ''LLNL Workshop on Extreme States of Materials: Warm Dense Matter to NIF'' which was held on 20, 21, and 22 February 2002 at the Wente Conference Center in Livermore, CA. The warm dense matter regime, the transitional phase space region between cold material and hot plasma, is presently poorly understood. The drive to understand the nature of matter in this regime is sparking scientific activity worldwide. In addition to pure scientific interest, finite temperature dense matter occurs in the regimes of interest to the SSMP (Stockpile Stewardship Materials Program). So that obtaining a better understanding of WDM is important to performing effective experiments at, e.g., NIF, a primary mission of LLNL. At this workshop we examined current experimental and theoretical work performed at, and in conjunction with, LLNL to focus future activities and define our role in this rapidly emerging research area. On the experimental front LLNL plays a leading role in three of the five relevant areas and has the opportunity to become a major player in the other two. Discussion at the workshop indicated that the path forward for the experimental efforts at LLNL were two fold: First, we are doing reasonable baseline work at SPLs, HE, and High Energy Lasers with more effort encouraged. Second, we need to plan effectively for the next evolution in large scale facilities, both laser (NIF) and Light/Beam sources (LCLS/TESLA and GSI) Theoretically, LLNL has major research advantages in areas as diverse as the thermochemical approach to warm dense matter equations of state to first principles molecular dynamics simulations. However, it was clear that there is much work to be done theoretically to understand warm dense matter. Further, there is a need for a close collaboration between the generation of verifiable experimental data that can provide benchmarks of both the experimental techniques and the theoretical capabilities

  8. Visual homing with a pan-tilt based stereo camera

    Science.gov (United States)

    Nirmal, Paramesh; Lyons, Damian M.

    2013-01-01

    Visual homing is a navigation method based on comparing a stored image of the goal location and the current image (current view) to determine how to navigate to the goal location. It is theorized that insects, such as ants and bees, employ visual homing methods to return to their nest. Visual homing has been applied to autonomous robot platforms using two main approaches: holistic and feature-based. Both methods aim at determining distance and direction to the goal location. Navigational algorithms using Scale Invariant Feature Transforms (SIFT) have gained great popularity in the recent years due to the robustness of the feature operator. Churchill and Vardy have developed a visual homing method using scale change information (Homing in Scale Space, HiSS) from SIFT. HiSS uses SIFT feature scale change information to determine distance between the robot and the goal location. Since the scale component is discrete with a small range of values, the result is a rough measurement with limited accuracy. We have developed a method that uses stereo data, resulting in better homing performance. Our approach utilizes a pan-tilt based stereo camera, which is used to build composite wide-field images. We use the wide-field images combined with stereo-data obtained from the stereo camera to extend the keypoint vector described in to include a new parameter, depth (z). Using this info, our algorithm determines the distance and orientation from the robot to the goal location. We compare our method with HiSS in a set of indoor trials using a Pioneer 3-AT robot equipped with a BumbleBee2 stereo camera. We evaluate the performance of both methods using a set of performance measures described in this paper.

  9. Mindfulness reduces the correspondence bias.

    Science.gov (United States)

    Hopthrow, Tim; Hooper, Nic; Mahmood, Lynsey; Meier, Brian P; Weger, Ulrich

    2017-03-01

    The correspondence bias (CB) refers to the idea that people sometimes give undue weight to dispositional rather than situational factors when explaining behaviours and attitudes. Three experiments examined whether mindfulness, a non-judgmental focus on the present moment, could reduce the CB. Participants engaged in a brief mindfulness exercise (the raisin task), a control task, or an attention to detail task before completing a typical CB measure involving an attitude-attribution paradigm. The results indicated that participants in the mindfulness condition experienced a significant reduction in the CB compared to participants in the control or attention to detail conditions. These results suggest that mindfulness training can play a unique role in reducing social biases related to person perception.

  10. Applications of Bohr's correspondence principle

    Science.gov (United States)

    Crawford, Frank S.

    1989-07-01

    The Bohr correspondence-principle (cp) formula dE/dn=ℏω is presented (ω is the classical angular frequency) and its predicted energy levels En are compared to those given by the stationary state solutions of the Schrödinger equation, first for several examples in one dimension (1D), including the ``quantum bouncer,'' and then for several examples in three dimensions (3D), including the hydrogen atom and the isotropic harmonic oscillator. For the 3-D cases, the cp predictions based on classical circular orbits are compared with the ``circlelike'' Schrödinger solutions (those with the lowest energy eigenvalue for a given l) and the cp predictions based on classical ``needle'' orbits (having zero angular momentum) with the Schrödinger l=0 solutions. For the H atom and the isotropic oscillator, the cp prediction does not depend on the classical orbit chosen because of a ``degeneracy'': the fact that for these systems ω is independent of the orbit. As a more stringent test of the cp, analogous nondegenerate systems V=-k/r3/2 in place of the H-atom potential V=-e2/r and V=kr4 in place of the oscillator potential V=(1/2)mω2r2 are therefore considered. An interesting anomaly that occurs for the harmonic oscillator and its nondegenerate analog V=kr4 is encountered (but not for the H atom nor its nondegenerate analog V=-k/r3/2), wherein half of the states predicted by application of the cp to the needle orbits are ``spurious'' in that there are no corresponding Schrödinger l=0 states. The assumption that generated the spurious cp states is uncovered—a plausible, but erroneous factor of 2 in calculating the classical frequency—and thus the spurious states are eliminated.

  11. Incremental Multi-view 3D Reconstruction Starting from Two Images Taken by a Stereo Pair of Cameras

    Science.gov (United States)

    El hazzat, Soulaiman; Saaidi, Abderrahim; Karam, Antoine; Satori, Khalid

    2015-03-01

    In this paper, we present a new method for multi-view 3D reconstruction based on the use of a binocular stereo vision system constituted of two unattached cameras to initialize the reconstruction process. Afterwards , the second camera of stereo vision system (characterized by varying parameters) moves to capture more images at different times which are used to obtain an almost complete 3D reconstruction. The first two projection matrices are estimated by using a 3D pattern with known properties. After that, 3D scene points are recovered by triangulation of the matched interest points between these two images. The proposed approach is incremental. At each insertion of a new image, the camera projection matrix is estimated using the 3D information already calculated and new 3D points are recovered by triangulation from the result of the matching of interest points between the inserted image and the previous image. For the refinement of the new projection matrix and the new 3D points, a local bundle adjustment is performed. At first, all projection matrices are estimated, the matches between consecutive images are detected and Euclidean sparse 3D reconstruction is obtained. So, to increase the number of matches and have a more dense reconstruction, the Match propagation algorithm, more suitable for interesting movement of the camera, was applied on the pairs of consecutive images. The experimental results show the power and robustness of the proposed approach.

  12. Effects of image compression and illumination on digital terrain models for the stereo camera of the BepiColombo mission

    Science.gov (United States)

    Re, C.; Simioni, E.; Cremonese, G.; Roncella, R.; Forlani, G.; Langevin, Y.; Da Deppo, V.; Naletto, G.; Salemi, G.

    2017-02-01

    The great amount of data that will be produced during the imaging of Mercury by the stereo camera (STC) of the BepiColombo mission needs a compromise with the restrictions imposed by the band downlink that could drastically reduce the duration and frequency of the observations. The implementation of an on-board real time data compression strategy preserving as much information as possible is therefore mandatory. The degradation that image compression might cause to the DTM accuracy is worth to be investigated. During the stereo-validation procedure of the innovative STC imaging system, several image pairs of an anorthosite sample and a modelled piece of concrete have been acquired under different illumination angles. This set of images has been used to test the effects of the compression algorithm (Langevin and Forni, 2000) on the accuracy of the DTM produced by dense image matching. Different configurations taking in account at the same time both the illumination of the surface and the compression ratio, have been considered. The accuracy of the DTMs is evaluated by comparison with a high resolution laser-scan acquisition of the same targets. The error assessment includes also an analysis on the image plane indicating the influence of the compression procedure on the image measurements.

  13. Structural Transitions in Dense Networks

    CERN Document Server

    Lambiotte, R; Bhat, U; Redner, S

    2016-01-01

    We introduce an evolving network model in which a new node attaches to a randomly selected target node and also to each of its neighbors with probability $p$. The resulting network is sparse for $p<\\frac{1}{2}$ and dense (average degree increasing with number of nodes $N$) for $p\\geq \\frac{1}{2}$. In the dense regime, individual networks realizations built by this copying mechanism are disparate and not self-averaging. Further, there is an infinite sequence of structural anomalies at $p=\\frac{2}{3}$, $\\frac{3}{4}$, $\\frac{4}{5}$, etc., where the dependences on $N$ of the number of triangles (3-cliques), 4-cliques, undergo phase transitions. When linking to second neighbors of the target can occur, the probability that the resulting graph is complete---where all nodes are connected---is non-zero as $N\\to\\infty$.

  14. Holographic Renormalization in Dense Medium

    Directory of Open Access Journals (Sweden)

    Chanyong Park

    2014-01-01

    describes a dense medium at finite temperature, is investigated in this paper. In a dense medium, two different thermodynamic descriptions are possible due to an additional conserved charge. These two different thermodynamic ensembles are classified by the asymptotic boundary condition of the bulk gauge field. It is also shown that in the holographic renormalization regularity of all bulk fields can reproduce consistent thermodynamic quantities and that the Bekenstein-Hawking entropy is nothing but the renormalized thermal entropy of the dual field theory. Furthermore, we find that the Reissner-Nordström AdS black brane is dual to a theory with conformal matter as expected, whereas a charged black brane with a nontrivial dilaton profile is mapped to a theory with nonconformal matter although its leading asymptotic geometry still remains as AdS space.

  15. Radiative properties of dense nanofluids.

    Science.gov (United States)

    Wei, Wei; Fedorov, Andrei G; Luo, Zhongyang; Ni, Mingjiang

    2012-09-01

    The radiative properties of dense nanofluids are investigated. For nanofluids, scattering and absorbing of electromagnetic waves by nanoparticles, as well as light absorption by the matrix/fluid in which the nanoparticles are suspended, should be considered. We compare five models for predicting apparent radiative properties of nanoparticulate media and evaluate their applicability. Using spectral absorption and scattering coefficients predicted by different models, we compute the apparent transmittance of a nanofluid layer, including multiple reflecting interfaces bounding the layer, and compare the model predictions with experimental results from the literature. Finally, we propose a new method to calculate the spectral radiative properties of dense nanofluids that shows quantitatively good agreement with the experimental results.

  16. Dilatons for Dense Hadronic Matter

    CERN Document Server

    Lee, Hyun Kyu

    2009-01-01

    The idea that the explicit breaking of scale invariance by the trace anomaly of QCD can be rephrased as a spontaneous breaking has been recently exploited to capture the low-energy strong interaction dynamics of dense (and also hot) matter in terms of two dilaton fields, the "soft" (chi_s) and the "hard" (chi_h) fields, in the frame work of the hidden local gauge symmetry. In the Freund-Nambu model, the spontaneous symmetry breaking of scale symmetry is induced by an explicitly breaking term, while the spontaneous symmetry breaking is possible in the flat potential model which is scale symmetric. We discuss the interplay of the soft and hard dilatons using the spontaneously broken scale symmetry schemes and uncover a novel structure of dense matter hitherto unexplored.

  17. Indoor and Outdoor Depth Imaging of Leaves With Time-of-Flight and Stereo Vision Sensors

    DEFF Research Database (Denmark)

    Kazmi, Wajahat; Foix, Sergi; Alenya, Guilliem

    2014-01-01

    high frame rate accurate depth data under suitable conditions. We introduce metrics for performance evaluation over a small region of interest. Based on these metrics, we analyze and compare depth imaging of leaf under indoor (room) and outdoor (shadow and sunlight) conditions by varying exposure times...... but is computationally much more expensive as compared to local correlation. Finally, we propose a method to increase the dynamic range of ToF cameras for a scene involving both shadow and sunlight exposures at the same time by taking advantage of camera flags (PMD) or confidence matrix (SwissRanger)....... of the sensors. Performance of three different ToF cameras (PMD CamBoard, PMD CamCube and SwissRanger SR4000) is compared against selected stereo correspondence algorithms (local correlation and graph cuts). PMD CamCube has better cancelation of sunlight, followed by CamBoard, while SwissRanger SR4000 performs...

  18. Interactive stereo games to improve vision in children with amblyopia using dichoptic stimulation

    Science.gov (United States)

    Herbison, Nicola; Ash, Isabel M.; MacKeith, Daisy; Vivian, Anthony; Purdy, Jonathan H.; Fakis, Apostolos; Cobb, Sue V.; Hepburn, Trish; Eastgate, Richard M.; Gregson, Richard M.; Foss, Alexander J. E.

    2015-03-01

    Amblyopia is a common condition affecting 2% of all children and traditional treatment consists of either wearing a patch or penalisation. We have developed a treatment using stereo technology, not to provide a 3D image but to allow dichoptic stimulation. This involves presenting an image with the same background to both eyes but with features of interest removed from the image presented to the normal eye with the aim to preferentially stimulated visual development in the amblyopic, or lazy, eye. Our system, called I-BiT can use either a game or a video (DVD) source as input. Pilot studies show that this treatment is effective with short treatment times and has proceeded to randomised controlled clinical trial. The early indications are that the treatment has a high degree of acceptability and corresponding good compliance.

  19. Line Matching Across Views Based on Multiple Line Matching Across Views Based on Multiple View Stereo

    Institute of Scientific and Technical Information of China (English)

    FU Kang-Ping; SHEN Shu-Han; HU Zhan-Yi

    2014-01-01

    A graph-based multiple view line matching method is proposed based on results of multiple view stereo (MVS) al-gorithms. With the 3D points and their visibility information provided by MVS, point-line correspondences are firstly established through 3D-to-2D re-projection. Each image line detected in different views is described using a 3D point set as well as a unit vector representing its coarse 3D direction. From such a description, pairwise similarity and consistency are evaluated. Then, a graph is constructed to contain all image lines as nodes. To get a unified node distance measure, a spectral graph analysis method is employed. Finally, a modified DBSCAN algorithm is introduced to obtain reliable line matches from the graph. Experiments show that our method is more robust and exhibits better accuracy than the existing methods.

  20. 6-DOF MOTION AND CENTER OF ROTATION ESTIMATION BASED ON STEREO VISION

    Institute of Scientific and Technical Information of China (English)

    CAO Wanpeng; BI Wei; CHE Rensheng; GUO Wenbo; YE Dong

    2008-01-01

    A new motion model and estimation algorithm is proposed to compute the general rigid motion object's 6-DOF motion parameters and center of rotation based on stereo vision. The object's 6-DOF motion model is designed from the rigid object's motion character under the two defined reference frames. According to the rigid object's motion model and motion dynamics knowledge, the corresponding motion algorithm to compute the 6-DOF motion parameters is worked out. By the rigid object pure rotation motion model and space sphere geometry knowledge, the center of rotation may be calculated after eliminating the translation motion out of the 6-DOF motion. The motion equations are educed based on the motion model and the closed-form solutions are figured out. To heighten the motion estimation algorithm's robust, RANSAC algorithm is applied to delete the outliers. Simulation and real experiments are conducted and the experiment results are analyzed. The results prove the motion model's correction and algorithm's validity.

  1. A Simple Way to Estimate the Soft X-ray Class of Far-Side Solar Flares Observed with STEREO/EUVI

    CERN Document Server

    Chertok, I M; Grechnev, V V

    2015-01-01

    Around the peaks of substantial flares, bright artifact nearly horizontal saturation streaks (B-streaks) corresponding to the brightest parts of the flare sources appear in the STEREO/EUVI 195 \\AA\\ images. We show that the length of such B-streaks can be used for the solution of an actual problem of evaluating the soft X-ray flux and class of far-side flares registered with double STEREO spacecraft but invisible from Earth. For this purpose from data on about 350 flares observed from January 2007 to July 2014 (mainly exceeding the GOES M1.0 level) both with GOES and STEREO, an empirical relation is established correlating the GOES 1-8 \\AA\\ peak flux and the B-streak length. This allowed us for the same years to estimate the soft X-ray classes for approximately 65 strong far-side flares observed by STEREO. The results of this simple and prompt method are consistent with the estimations of Nitta et al. (Solar Phys., 288, 241, 2013) based on the calculations of the EUVI full-disk digital number output. In additi...

  2. Correspondence Truth and Quantum Mechanics

    CERN Document Server

    Karakostas, Vassilios

    2015-01-01

    The logic of a physical theory reflects the structure of the propositions referring to the behaviour of a physical system in the domain of the relevant theory. It is argued in relation to classical mechanics that the propositional structure of the theory allows truth-value assignment in conformity with the traditional conception of a correspondence theory of truth. Every proposition in classical mechanics is assigned a definite truth value, either 'true' or 'false', describing what is actually the case at a certain moment of time. Truth-value assignment in quantum mechanics, however, differs; it is known, by means of a variety of 'no go' theorems, that it is not possible to assign definite truth values to all propositions pertaining to a quantum system without generating a Kochen-Specker contradiction. In this respect, the Bub-Clifton 'uniqueness theorem' is utilized for arguing that truth-value definiteness is consistently restored with respect to a determinate sublattice of propositions defined by the state...

  3. SAD5 Stereo Correlation Line-Striping in an FPGA

    Science.gov (United States)

    Villalpando, Carlos Y.; Morfopoulos, Arin C.

    2011-01-01

    High precision SAD5 stereo computations can be performed in an FPGA (field-programmable gate array) at much higher speeds than possible in a conventional CPU (central processing unit), but this uses large amounts of FPGA resources that scale with image size. Of the two key resources in an FPGA, Slices and BRAM (block RAM), Slices scale linearly in the new algorithm with image size, and BRAM scales quadratically with image size. An approach was developed to trade latency for BRAM by sub-windowing the image vertically into overlapping strips and stitching the outputs together to create a single continuous disparity output. In stereo, the general rule of thumb is that the disparity search range must be 1/10 the image size. In the new algorithm, BRAM usage scales linearly with disparity search range and scales again linearly with line width. So a doubling of image size, say from 640 to 1,280, would in the previous design be an effective 4 of BRAM usage: 2 for line width, 2 again for disparity search range. The minimum strip size is twice the search range, and will produce an output strip width equal to the disparity search range. So assuming a disparity search range of 1/10 image width, 10 sequential runs of the minimum strip size would produce a full output image. This approach allowed the innovators to fit 1280 960 wide SAD5 stereo disparity in less than 80 BRAM, 52k Slices on a Virtex 5LX330T, 25% and 24% of resources, respectively. Using a 100-MHz clock, this build would perform stereo at 39 Hz. Of particular interest to JPL is that there is a flight qualified version of the Virtex 5: this could produce stereo results even for very large image sizes at 3 orders of magnitude faster than could be computed on the PowerPC 750 flight computer. The work covered in the report allows the stereo algorithm to run on much larger images than before, and using much less BRAM. This opens up choices for a smaller flight FPGA (which saves power and space), or for other algorithms

  4. Non-dense domain operator matrices and Cauchy problems

    CERN Document Server

    Lalaoui Rhali, S

    2002-01-01

    In this work, we study Cauchy problems with non-dense domain operator matrices. By assuming that the entries of an unbounded operator matrix are Hille-Yosida operators, we give a necessary and sufficient condition ensuring that the part of this operator matrix generates a semigroup in the closure of its domain. This allows us to prove the well-posedness of the corresponding Cauchy problem. Our results are applied to delay and neutral differential equations.

  5. Performance evaluation of similarity measures for dense multimodal stereovision

    Science.gov (United States)

    Yaman, Mustafa; Kalkan, Sinan

    2016-05-01

    Multimodal imaging systems have recently been drawing attention in fields such as medical imaging, remote sensing, and video surveillance systems. In such systems, estimating depth has become possible due to the promising progress of multimodal matching techniques. We perform a systematic performance evaluation of similarity measures frequently used in the literature for dense multimodal stereovision. The evaluated measures include mutual information (MI), sum of squared distances, normalized cross-correlation, census transform, local self-similarity (LSS) as well as descriptors adopted to multimodal settings, like scale invariant feature transform (SIFT), speeded-up robust features (SURF), histogram of oriented gradients (HOG), binary robust independent elementary features, and fast retina keypoint (FREAK). We evaluate the measures over datasets we generated, compiled, and provided as a benchmark and compare the performances using the Winner Takes All method. The datasets are (1) synthetically modified four popular pairs from the Middlebury Stereo Dataset (namely, Tsukuba, Venus, Cones, and Teddy) and (2) our own multimodal image pairs acquired using the infrared and the electro-optical cameras of a Kinect device. The results show that MI and HOG provide promising results for multimodal imagery, and FREAK, SURF, SIFT, and LSS can be considered as alternatives depending on the multimodality level and the computational complexity requirements of the intended application.

  6. Constructing Dense Graphs with Unique Hamiltonian Cycles

    Science.gov (United States)

    Lynch, Mark A. M.

    2012-01-01

    It is not difficult to construct dense graphs containing Hamiltonian cycles, but it is difficult to generate dense graphs that are guaranteed to contain a unique Hamiltonian cycle. This article presents an algorithm for generating arbitrarily large simple graphs containing "unique" Hamiltonian cycles. These graphs can be turned into dense graphs…

  7. Extracting Buildings from True Color Stereo Aerial Images Using a Decision Making Strategy

    Directory of Open Access Journals (Sweden)

    Eufemia Tarantino

    2011-07-01

    Full Text Available The automatic extraction of buildings from true color stereo aerial imagery in a dense built-up area is the main focus of this paper. Our approach strategy aimed at reducing the complexity of the image content by means of a three-step procedure combining reliable geospatial image analysis techniques. Even if it is a rudimentary first step towards a more general approach, the method presented proved useful in urban sprawl studies for rapid map production in flat area by retrieving indispensable information on buildings from scanned historic aerial photography. After the preliminary creation of a photogrammetric model to manage Digital Surface Model and orthophotos, five intermediate mask-layers data (Elevation, Slope, Vegetation, Shadow, Canny, Shadow, Edges were processed through the combined use of remote sensing image processing and GIS software environments. Lastly, a rectangular building block model without roof structures (Level of Detail, LoD1 was automatically generated. System performance was evaluated with objective criteria, showing good results in a complex urban area featuring various types of building objects.

  8. Kinect v2 and RGB Stereo Cameras Integration for Depth Map Enhancement

    Science.gov (United States)

    Ravanelli, R.; Nascetti, A.; Crespi, M.

    2016-06-01

    Today range cameras are widespread low-cost sensors based on two different principles of operation: we can distinguish between Structured Light (SL) range cameras (Kinect v1, Structure Sensor, ...) and Time Of Flight (ToF) range cameras (Kinect v2, ...). Both the types are easy to use 3D scanners, able to reconstruct dense point clouds at high frame rate. However the depth maps obtained are often noisy and not enough accurate, therefore it is generally essential to improve their quality. Standard RGB cameras can be a valuable solution to solve such issue. The aim of this paper is therefore to evaluate the integration feasibility of these two different 3D modelling techniques, characterized by complementary features and based on standard low-cost sensors. For this purpose, a 3D model of a DUPLOTM bricks construction was reconstructed both with the Kinect v2 range camera and by processing one stereo pair acquired with a Canon Eos 1200D DSLR camera. The scale of the photgrammetric model was retrieved from the coordinates measured by Kinect v2. The preliminary results are encouraging and show that the foreseen integration could lead to an higher metric accuracy and a major level of completeness with respect to that obtained by using only separated techniques.

  9. Refinement of Stereo Image Analysis Using Photometric Shape Recovery as AN Alternative to Bundle Adjustment

    Science.gov (United States)

    Grumpe, A.; Schröer, C.; Kauffmann, S.; Fricke, T.; Wöhler, C.; Mall, U.

    2016-06-01

    Topographic mapping, e.g. the generation of Digital Elevation Models (DEM), is of general interest to the remote sensing community and scientific research. Commonly, photogrammetric methods, e.g. stereo image analysis methods (SIAM) or bundle adjustment methods (BAM), are applied to derive 3D information based on multiple images of an area. These methods require the detection of control points, i.e. common points within multiple images, which relies on a similarity measure and usually yields a sparse map of 3D points. The full spatial DEM is then obtained by interpolation techniques or imposed restrictions, e.g. smoothness constraints. Since BAM utilizes all images of the area, it is assumed to provide a more accurate DEM than SIAM which utilizes only pairs of images. Intensity-based shape recovery, e.g. shape from shading (SfS), utilizes the reflectance behavior of the object surface and thus provides a dense map of relative height changes, which provide the possibility to refine the photogrammetric DEMs. Based on Rosetta NavCam images of 67P/Churyumov-Gerasimenko we compare intensity-based DEM refinement methods which use DEMs obtained based on SIAM and BAM as a reference. We show that both the SIAM based DEM refinement and the BAM based DEM refinement are of similar quality. It is thus possible to derive DEMs of high lateral resolution by applying the intensity-based refinement to the less complex SIAM.

  10. UPDATING LIDAR DSM USING HIGH RESOLUTION STEREO-BASED DSM FROM WORLDVIEW-2

    Directory of Open Access Journals (Sweden)

    H. Arefi

    2014-10-01

    Full Text Available In recent years, the acquisition and processing techniques of high resolution Digital Surface Models (DSM have been rapidly improved. Airborne LiDAR production as a well-known and high quality DSM is still unbeatable in elevation accuracy and highly produced dense point clouds. In this paper, the objective is to update an old but high quality DSM produced by LiDAR data using a DSM generated from high resolution stereo satellite images. A classification-base algorithm is proposed to extract building changes between DSMs in two epochs. For image classification procedure, the DSM and Worldview-2 orthorectified images have been used as input data for a fuzzy-based classification method. Then, extracted buildings are classified into unchanged, destroyed, new, and changed classes. In this study a dataset related to Munich city, has been utilized to test the experimental investigation. The implemented qualitative and quantitative assessments demonstrate high quality as well as high feasibility of the proposed approach.

  11. Dense range map reconstruction from a versatile robotic sensor system with an active trinocular vision and a passive binocular vision.

    Science.gov (United States)

    Kim, Min Young; Lee, Hyunkee; Cho, Hyungsuck

    2008-04-10

    One major research issue associated with 3D perception by robotic systems is the creation of efficient sensor systems that can generate dense range maps reliably. A visual sensor system for robotic applications is developed that is inherently equipped with two types of sensor, an active trinocular vision and a passive stereo vision. Unlike in conventional active vision systems that use a large number of images with variations of projected patterns for dense range map acquisition or from conventional passive vision systems that work well on specific environments with sufficient feature information, a cooperative bidirectional sensor fusion method for this visual sensor system enables us to acquire a reliable dense range map using active and passive information simultaneously. The fusion algorithms are composed of two parts, one in which the passive stereo vision helps active vision and the other in which the active trinocular vision helps the passive one. The first part matches the laser patterns in stereo laser images with the help of intensity images; the second part utilizes an information fusion technique using the dynamic programming method in which image regions between laser patterns are matched pixel-by-pixel with help of the fusion results obtained in the first part. To determine how the proposed sensor system and fusion algorithms can work in real applications, the sensor system is implemented on a robotic system, and the proposed algorithms are applied. A series of experimental tests is performed for a variety of configurations of robot and environments. The performance of the sensor system is discussed in detail.

  12. Correspondence principle in cochlear mechanics.

    Science.gov (United States)

    de Boer, E

    1982-06-01

    When only long waves play the most important part in the cochlea, the response can be described by a most simplified model, the one-dimensional model. When short waves are to be included, a more complex model is needed. The response then depends on the dimensionality of the model and is much harder to obtain. This applies especially to the region in the neighborhood of the point where the basilar membrane shows resonance. Both two- and three-dimensional models have been studied to assess the effects of short and long waves. The relative importance of the part played by short waves depends on the damping constant (or loss factor )delta associated with the resonance of the basilar membrane (BM). For very small delta a three-dimensional model is really necessary, it cannot be replaced by a model of lower dimensionality. When delta is small, but not too small, the three-dimensional model can be made equivalent to a two-dimensional one, provided the latter is modified ina specific manner. This paper shows why this is so and which conditions have to be met. The two-dimensional model must undergo two modifications to effect this equivalence. The first modification ensures that the model has the same long-wave behavior. In the second place, a specific additional mass ("added mass") reactance should be added to Z(kappa). An expression for the limiting value of delta, above which this correspondence is valid, is given in the paper. A second, larger, limit is presented as well: when delta is above this limit, the responses of both the three-dimensional and the two-dimensional model are equivalent to that of an appropriately chosen one-dimensional model. In this case too, long-wave behavior must be matched and an "added mass" reactance must be included in Z(kappa). This holds true for the entire cochlea including the region of resonance. For both types of transition the amount of "added mass" is given.

  13. Modeling vegetation heights from high resolution stereo aerial photography: an application for broad-scale rangeland monitoring.

    Science.gov (United States)

    Gillan, Jeffrey K; Karl, Jason W; Duniway, Michael; Elaksher, Ahmed

    2014-11-01

    Vertical vegetation structure in rangeland ecosystems can be a valuable indicator for assessing rangeland health and monitoring riparian areas, post-fire recovery, available forage for livestock, and wildlife habitat. Federal land management agencies are directed to monitor and manage rangelands at landscapes scales, but traditional field methods for measuring vegetation heights are often too costly and time consuming to apply at these broad scales. Most emerging remote sensing techniques capable of measuring surface and vegetation height (e.g., LiDAR or synthetic aperture radar) are often too expensive, and require specialized sensors. An alternative remote sensing approach that is potentially more practical for managers is to measure vegetation heights from digital stereo aerial photographs. As aerial photography is already commonly used for rangeland monitoring, acquiring it in stereo enables three-dimensional modeling and estimation of vegetation height. The purpose of this study was to test the feasibility and accuracy of estimating shrub heights from high-resolution (HR, 3-cm ground sampling distance) digital stereo-pair aerial images. Overlapping HR imagery was taken in March 2009 near Lake Mead, Nevada and 5-cm resolution digital surface models (DSMs) were created by photogrammetric methods (aerial triangulation, digital image matching) for twenty-six test plots. We compared the heights of individual shrubs and plot averages derived from the DSMs to field measurements. We found strong positive correlations between field and image measurements for several metrics. Individual shrub heights tended to be underestimated in the imagery, however, accuracy was higher for dense, compact shrubs compared with shrubs with thin branches. Plot averages of shrub height from DSMs were also strongly correlated to field measurements but consistently underestimated. Grasses and forbs were generally too small to be detected with the resolution of the DSMs. Estimates of

  14. Modeling vegetation heights from high resolution stereo aerial photography: an application for broad-scale rangeland monitoring

    Science.gov (United States)

    Gillan, Jeffrey K.; Karl, Jason W.; Duniway, Michael; Elaksher, Ahmed

    2014-01-01

    Vertical vegetation structure in rangeland ecosystems can be a valuable indicator for assessing rangeland health and monitoring riparian areas, post-fire recovery, available forage for livestock, and wildlife habitat. Federal land management agencies are directed to monitor and manage rangelands at landscapes scales, but traditional field methods for measuring vegetation heights are often too costly and time consuming to apply at these broad scales. Most emerging remote sensing techniques capable of measuring surface and vegetation height (e.g., LiDAR or synthetic aperture radar) are often too expensive, and require specialized sensors. An alternative remote sensing approach that is potentially more practical for managers is to measure vegetation heights from digital stereo aerial photographs. As aerial photography is already commonly used for rangeland monitoring, acquiring it in stereo enables three-dimensional modeling and estimation of vegetation height. The purpose of this study was to test the feasibility and accuracy of estimating shrub heights from high-resolution (HR, 3-cm ground sampling distance) digital stereo-pair aerial images. Overlapping HR imagery was taken in March 2009 near Lake Mead, Nevada and 5-cm resolution digital surface models (DSMs) were created by photogrammetric methods (aerial triangulation, digital image matching) for twenty-six test plots. We compared the heights of individual shrubs and plot averages derived from the DSMs to field measurements. We found strong positive correlations between field and image measurements for several metrics. Individual shrub heights tended to be underestimated in the imagery, however, accuracy was higher for dense, compact shrubs compared with shrubs with thin branches. Plot averages of shrub height from DSMs were also strongly correlated to field measurements but consistently underestimated. Grasses and forbs were generally too small to be detected with the resolution of the DSMs. Estimates of

  15. Evaluation of the short-term sea cliff retreat along the Tróia-Sines Embayed Coast (Costa da Galé sector), using stereo digital aerial images and Bayesian inference

    Science.gov (United States)

    Gama, C.; Jalobeanu, A.

    2011-12-01

    Monitoring the sediment budget of coastal systems is essential to understand the costal equilibrium, and is an important aspect to be considered in coastal management. Thus, the identification and the quantitative evaluation of sedimentary sources and sinks are the first steps towards a better understanding of the dynamics of coastal morphology. The Tróia-Sines Embayed Coast (TSEC) in the southwest Portuguese coast corresponds to a continuous sandy beach that extends for approximately 65 km. It is limited at north by the Sado river estuary and at south by the Sines cape. Beaches are discontinuously limited landward by dunes (≈42 km) and by sea cliffs (≈18 km) made of poorly consolidated Plio-Plistocene detrital deposits. Cliff erosion by subaerial processes or gullying is a continuous phenomenon that contributes a significant amount of sediment to the TSEC coastal system, which is what we want to measure. Mainly due to winter rainfall, sea cliffs develop debris fans at the backshore inner limit, therefore we chose to make morphological measurements at one year interval. Thus, two series digital aerial images at 20 cm resolution were acquired in Oct 2008 and July 2009, supported by a collection of ground control points (GCP) to constrain the sensor orientation. Digital aerial stereo image pairs are used as main data source to reconstruct digital surface models (DSM). A new stereo photogrammetric method is used, based on dense disparity maps and Bayesian inference (Jalobeanu et al, 2010 and Jalobeanu, 2011). The originality of this method is in the computation of the spatial distribution of elevation errors in the DSM using stochastic modelling and probabilistic inference, which helps to detect the statistically significant changes in the estimated topography. The difference between the two generated DSMs is used to characterize the variability of the main subaerial beach morphodynamics parameters, such as: i) the alongshore beach configuration; ii) the beach

  16. Single detector stereo-SCIDAR for Mount Stromlo: data analysis

    Science.gov (United States)

    Korkiakoski, Visa; Osborn, James; Grosse, Doris; Thorn, Elliott; Piatrou, Piotr; Bennet, Francis; Rigaut, Francois

    2016-09-01

    Satellite tracking and imaging is conducted by the ANU Research School of Astronomy and Astrophysics (RSAA) and Electro-Optic Systems at Mount Stromlo as part of the Space Environment Management Cooperative Research Centre to support debris tracking. To optimally design adaptive optics systems for those applications, it is important to know the atmospheric profile, i.e. how the turbulence is distributed as a function altitude. We have designed a new stereo-SCIDAR instrument1 to conduct a site characterisation campaign at Mount Stromlo site. This paper summarises our current progress: specifications, design choices and post-processing techniques. In particular, we compare two different post-processing algorithms for stereo-SCIDAR, using simulated data cubes. One of the codes is implemented by the RSAA, the other by the Centre for Advanced Instrumentation, University of Durham. The comparison shows that the current implementations of both codes produce decent results. However, we can see potential for further improvements.

  17. Field study of sound exposure by personal stereo

    DEFF Research Database (Denmark)

    Ordoñez, Rodrigo Pizarro; Reuter, Karen; Hammershøi, Dorte

    2006-01-01

    on young people's habitual sound exposure to personal stereos has been carried out using a measurement method according to principles of ISO 11904-2:2004. Additionally the state of their hearing has also been assessed. This presentation deals with the methodological aspects relating to the quantification......A number of large scale studies suggest that the exposure level used with personal stereo systems should raise concern. High levels can be produced by most commercially available mp3 players, and they are generally used in high background noise levels (i.e., while in a bus or rain). A field study...... of habitual use, estimation of listening levels and exposure levels, and assessment of their state of hearing, by either threshold determination or OAE measurement, with a special view to the general validity of the results (uncertainty factors and their magnitude)....

  18. Three dimensional reconstruction of conventional stereo optic disc image.

    Science.gov (United States)

    Kong, H J; Kim, S K; Seo, J M; Park, K H; Chung, H; Park, K S; Kim, H C

    2004-01-01

    Stereo disc photograph was analyzed and reconstructed as 3 dimensional contour image to evaluate the status of the optic nerve head for the early detection of glaucoma and the evaluation of the efficacy of treatment. Stepwise preprocessing was introduced to detect the edge of the optic nerve head and retinal vessels and reduce noises. Paired images were registered by power cepstrum method and zero-mean normalized cross-correlation. After Gaussian blurring, median filter application and disparity pair searching, depth information in the 3 dimensionally reconstructed image was calculated by the simple triangulation formula. Calculated depth maps were smoothed through cubic B-spline interpolation and retinal vessels were visualized more clearly by adding reference image. Resulted 3 dimensional contour image showed optic cups, retinal vessels and the notching of the neural rim of the optic disc clearly and intuitively, helping physicians in understanding and interpreting the stereo disc photograph.

  19. A Robust Time Efficient Watermarking Technique for Stereo Images

    Directory of Open Access Journals (Sweden)

    M. A. Abdou

    2015-01-01

    Full Text Available Stereoscopic and multiview imaging techniques are used for reproducing a natural or real world scene. However, the fact that more information is displayed requires supporting technologies to ensure the storage and transmission of the sequences. Beyond these supports comes watermarking as a desirable alternative solution for copyright protection of stereo images and videos. This paper introduces a watermarking method applied to stereo images in wavelet domain. This method uses a particle swarm optimization (PSO evolutionary computation method. The aim is to solve computational complexity problems as well as satisfy an execution time that complies with normal PCs or smart phones processors. Robustness against image attacks is tested, and results are shown.

  20. Fast and Robust Stereo Vision Algorithm for Obstacle Detection

    Institute of Scientific and Technical Information of China (English)

    Yi-peng Zhou

    2008-01-01

    Binocular computer vision is based on bionics, after the calibration through the camera head by double-exposure image synchronization, access to the calculation of two-dimensional image pixels of the three-dimensional depth information. In this paper, a fast and robust stereo vision algorithm is described to perform in-vehicle obstacles detection and characterization. The stereo algorithm which provides a suitable representation of the geometric content of the road scene is described, and an in-vehicle embedded system is presented. We present the way in which the algorithm is used, and then report experiments on real situations which show that our solution is accurate, reliable and efficient. In particular, both processes are fast, generic,robust to noise and bad conditions, and work even with partial occlusion.

  1. Temporally consistent virtual camera generation from stereo image sequences

    Science.gov (United States)

    Fox, Simon R.; Flack, Julien; Shao, Juliang; Harman, Phil

    2004-05-01

    The recent emergence of auto-stereoscopic 3D viewing technologies has increased demand for the creation of 3D video content. A range of glasses-free multi-viewer screens have been developed that require as many as 9 views generated for each frame of video. This presents difficulties in both view generation and transmission bandwidth. This paper examines the use of stereo video capture as a means to generate multiple scene views via disparity analysis. A machine learning approach is applied to learn relationships between disparity generated depth information and source footage, and to generate depth information in a temporally smooth manner for both left and right eye image sequences. A view morphing approach to multiple view rendering is described which provides an excellent 3D effect on a range of glasses-free displays, while providing robustness to inaccurate stereo disparity calculations.

  2. GPU-based real-time trinocular stereo vision

    Science.gov (United States)

    Yao, Yuanbin; Linton, R. J.; Padir, Taskin

    2013-01-01

    Most stereovision applications are binocular which uses information from a 2-camera array to perform stereo matching and compute the depth image. Trinocular stereovision with a 3-camera array has been proved to provide higher accuracy in stereo matching which could benefit applications like distance finding, object recognition, and detection. This paper presents a real-time stereovision algorithm implemented on a GPGPU (General-purpose graphics processing unit) using a trinocular stereovision camera array. Algorithm employs a winner-take-all method applied to perform fusion of disparities in different directions following various image processing techniques to obtain the depth information. The goal of the algorithm is to achieve real-time processing speed with the help of a GPGPU involving the use of Open Source Computer Vision Library (OpenCV) in C++ and NVidia CUDA GPGPU Solution. The results are compared in accuracy and speed to verify the improvement.

  3. Stereo Disparity through Cost Aggregation with Guided Filter

    Directory of Open Access Journals (Sweden)

    Pauline Tan

    2014-10-01

    Full Text Available Estimating the depth, or equivalently the disparity, of a stereo scene is a challenging problem in computer vision. The method proposed by Rhemann et al. in 2011 is based on a filtering of the cost volume, which gives for each pixel and for each hypothesized disparity a cost derived from pixel-by-pixel comparison. The filtering is performed by the guided filter proposed by He et al. in 2010. It computes a weighted local average of the costs. The weights are such that similar pixels tend to have similar costs. Eventually, a winner-take-all strategy selects the disparity with the minimal cost for each pixel. Non-consistent labels according to left-right consistency are rejected; a densification step can then be launched to fill the disparity map. The method can be used to solve other labeling problems (optical flow, segmentation but this article focuses on the stereo matching problem.

  4. Probing Cold Dense Nuclear Matter

    Energy Technology Data Exchange (ETDEWEB)

    Subedi, Ramesh; Shneor, R.; Monaghan, Peter; Anderson, Bryon; Aniol, Konrad; Annand, John; Arrington, John; Benaoum, Hachemi; Benmokhtar, Fatiha; Bertozzi, William; Boeglin, Werner; Chen, Jian-Ping; Choi, Seonho; Cisbani, Evaristo; Craver, Brandon; Frullani, Salvatore; Garibaldi, Franco; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Ibrahim, Hassan; Igarashi, Ryuichi; De Jager, Cornelis; Jans, Eddy; Jiang, Xiaodong; Kaufman, Lisa; Kelleher, Aidan; Kolarkar, Ameya; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Liyanage, Nilanga; Margaziotis, Demetrius; Markowitz, Pete; Marrone, Stefano; Mazouz, Malek; Meekins, David; Michaels, Robert; Moffit, Bryan; Perdrisat, Charles; Piasetzky, Eliazer; Potokar, Milan; Punjabi, Vina; Qiang, Yi; Reinhold, Joerg; Ron, Guy; Rosner, Guenther; Saha, Arunava; Sawatzky, Bradley; Shahinyan, Albert; Sirca, Simon; Slifer, Karl; Solvignon, Patricia; Sulkosky, Vince; Sulkosky, Vincent; Sulkosky, Vince; Sulkosky, Vincent; Urciuoli, Guido; Voutier, Eric; Watson, John; Weinstein, Lawrence; Wojtsekhowski, Bogdan; Wood, Stephen; Zheng, Xiaochao; Zhu, Lingyan

    2008-06-01

    The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, in which a proton is knocked out of the nucleus with high-momentum transfer and high missing momentum, show that in carbon-12 the neutron-proton pairs are nearly 20 times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.

  5. Probing Cold Dense Nuclear Matter

    CERN Document Server

    Subedi, R; Monaghan, P; Anderson, B D; Aniol, K; Annand, J; Arrington, J; Benaoum, H; Benmokhtar, F; Bertozzi, W; Boeglin, W; Chen, J -P; Choi, Seonho; Cisbani, E; Craver, B; Frullani, S; Garibaldi, F; Gilad, S; Gilman, R; Glamazdin, O; Hansen, J -O; Higinbotham, D W; Holmstrom, T; Ibrahim, H; Igarashi, R; De Jager, C W; Jans, E; Jiang, X; Kaufman, L; Kelleher, A; Kolarkar, A; Kumbartzki, G; LeRose, J J; Lindgren, R; Liyanage, N; Margaziotis, D J; Markowitz, P; Marrone, S; Mazouz, M; Meekins, D; Michaels, R; Moffit, B; Perdrisat, C F; Piasetzky, E; Potokar, M; Punjabi, V; Qiang, Y; Reinhold, J; Ron, G; Rosner, G; Saha, A; Sawatzky, B; Shahinyan, A; Širca, S; Slifer, K; Solvignon, P; Sulkosky, V; Urciuoli, G; Voutier, E; Watson, J W; Weinstein, L B; Wojtsekhowski, B; Wood, S; Zheng, X -C; Zhu, L; 10.1126/science.1156675

    2009-01-01

    The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, where a proton is knocked-out of the nucleus with high momentum transfer and high missing momentum, show that in 12C the neutron-proton pairs are nearly twenty times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars.

  6. Dilatons in Dense Baryonic Matter

    CERN Document Server

    Lee, Hyun Kyu

    2013-01-01

    We discuss the role of dilaton, which is supposed to be representing a special feature of scale symmetry of QCD, trace anomaly, in dense baryonic matter. The idea that the scale symmetry breaking of QCD is responsible for the spontaneous breaking of chiral symmetry is presented along the similar spirit of Freund-Nambu model. The incorporation of dilaton field in the hidden local symmetric parity doublet model is briefly sketched with the possible role of dilaton at high density baryonic matter, the emergence of linear sigma model in dilaton limit.

  7. The STEREO Mission: A New Approach to Space Weather Research

    Science.gov (United States)

    Kaiser, michael L.

    2006-01-01

    With the launch of the twin STEREO spacecraft in July 2006, a new capability will exist for both real-time space weather predictions and for advances in space weather research. Whereas previous spacecraft monitors of the sun such as ACE and SOH0 have been essentially on the sun-Earth line, the STEREO spacecraft will be in 1 AU orbits around the sun on either side of Earth and will be viewing the solar activity from distinctly different vantage points. As seen from the sun, the two spacecraft will separate at a rate of 45 degrees per year, with Earth bisecting the angle. The instrument complement on the two spacecraft will consist of a package of optical instruments capable of imaging the sun in the visible and ultraviolet from essentially the surface to 1 AU and beyond, a radio burst receiver capable of tracking solar eruptive events from an altitude of 2-3 Rs to 1 AU, and a comprehensive set of fields and particles instruments capable of measuring in situ solar events such as interplanetary magnetic clouds. In addition to normal daily recorded data transmissions, each spacecraft is equipped with a real-time beacon that will provide 1 to 5 minute snapshots or averages of the data from the various instruments. This beacon data will be received by NOAA and NASA tracking stations and then relayed to the STEREO Science Center located at Goddard Space Flight Center in Maryland where the data will be processed and made available within a goal of 5 minutes of receipt on the ground. With STEREO's instrumentation and unique view geometry, we believe considerable improvement can be made in space weather prediction capability as well as improved understanding of the three dimensional structure of solar transient events.

  8. Towards Segmenting Consumer Stereo Videos: Benchmark, Baselines and Ensembles

    OpenAIRE

    Chiu, Wei-Chen; GALASSO, Fabio; Fritz, Mario

    2016-01-01

    Are we ready to segment consumer stereo videos? The amount of this data type is rapidly increasing and encompasses rich information of appearance, motion and depth cues. However, the segmentation of such data is still largely unexplored. First, we propose therefore a new benchmark: videos, annotations and metrics to measure progress on this emerging challenge. Second, we evaluate several state of the art segmentation methods and propose a novel ensemble method based on recent spectral theory....

  9. Cellular neural networks for the stereo matching problem

    Energy Technology Data Exchange (ETDEWEB)

    Taraglio, S. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Innovazione; Zanela, A. [Rome Univ. `La Sapienza` (Italy). Dipt. di Fisica

    1997-03-01

    The applicability of the Cellular Neural Network (CNN) paradigm to the problem of recovering information on the tridimensional structure of the environment is investigated. The approach proposed is the stereo matching of video images. The starting point of this work is the Zhou-Chellappa neural network implementation for the same problem. The CNN based system we present here yields the same results as the previous approach, but without the many existing drawbacks.

  10. Near real-time stereo matching using geodesic diffusion.

    Science.gov (United States)

    De-Maeztu, Leonardo; Villanueva, Arantxa; Cabeza, Rafael

    2012-02-01

    Adaptive-weight algorithms currently represent the state of the art in local stereo matching. However, due to their computational requirements, these types of solutions are not suitable for real-time implementation. Here, we present a novel aggregation method inspired by the anisotropic diffusion technique used in image filtering. The proposed aggregation algorithm produces results similar to adaptive-weight solutions while reducing the computational requirements. Moreover, near real-time performance is demonstrated with a GPU implementation of the algorithm.

  11. Cellular neural networks for the stereo matching problem

    Energy Technology Data Exchange (ETDEWEB)

    Taraglio, S. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Innovazione; Zanela, A. [Rome Univ. `La Sapienza` (Italy). Dipt. di Fisica

    1997-03-01

    The applicability of the Cellular Neural Network (CNN) paradigm to the problem of recovering information on the tridimensional structure of the environment is investigated. The approach proposed is the stereo matching of video images. The starting point of this work is the Zhou-Chellappa neural network implementation for the same problem. The CNN based system we present here yields the same results as the previous approach, but without the many existing drawbacks.

  12. The Stereo Electron Spikes and the Interplanetary Magnetic Field

    Science.gov (United States)

    Jokipii, J. R.; Sheeley, N. R., Jr.; Wang, Y. M.; Giacalone, J.

    2016-12-01

    A recent paper (Klassen etal, 2015) discussed observations of a spike event of 55-65 keV electrons which occurred very nearly simultaneously at STEREO A and STEREO B, which at the time were separated in longitude by 38 degrees. The authors associated the spikes with a flare at the Sun near the footpoint of the nominal Archimedean spiral magnetic field line passing through STEREO A. The spike at STEREO A was delayed by 2.2 minutes from that at STEREOB. We discuss the observations in terms of a model in which the electrons, accelerated at the flare, propagate without significant scattering along magnetic field lines which separate or diverge as a function of radial distance from the Sun. The near simultaneity of the spikes at the two spacecraft is a natural consequence of this model. We interpret the divergence of the magnetic field lines as a consequence of field-line random walk and flux-tube expansion. We show that the field-line random walk in the absence of flux-tube expansion produces an rms spread of field lines significantly less than that which is required to produce to observed divergence. We find that observations of the solar wind and its source region at the time of the event can account for the observations in terms of propagation along interplanetary magnetic field-lines. Klassen, A., Dresing, N., Gomez-Herrero, R, and Heber, B., A&A 580, A115 (2015) Financial support for NS and YMW was provided by NASA and CNR.

  13. Investigating the Importance of Stereo Displays for Helicopter Landing Simulation

    Science.gov (United States)

    2016-08-11

    James Gaska, Logan Williams, Elizabeth Shoda, Charles Bullock, and Steve Hadley 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7...a helmet mounted display. A unique aspect of this research is that observer stereo acuity, fusion range, and contrast sensitivity were thoroughly...LIMITATION OF ABSTRACT SAR 18. NUMBER OF PAGES 11 19a. NAME OF RESPONSIBLE PERSON Logan Williams a. REPORT U b. ABSTRACT U c. THIS

  14. Stereo vision based SLAM using Rao-Blackwellised particle filter

    Institute of Scientific and Technical Information of China (English)

    Er-yong WU; Gong-yan LI; Zhi-yu XIANG; Ji-lin LIU

    2008-01-01

    We present an algorithm which can realize 3D stereo vision simultaneous localization and mapping (SLAM) for mobile robot in unknown outdoor environments, which means the 6-DOF motion and a sparse but persistent map of natural landmarks be constructed online only with a stereo camera. In mobile robotics research, we extend FastSLAM 2.0 like stereo vision SLAM with "pure vision" domain to outdoor environments. Unlike popular stochastic motion model used in conventional monocular vision SLAM, we utilize the ideas of structure from motion (SFM) for initial motion estimation, which is more suitable for the robot moving in large-scale outdoor, and textured environments. SIFT features are used as natural landmarks, and its 3D positions are constructed directly through triangulation. Considering the computational complexity and memory consumption,Bkd-tree and Best-Bin-First (BBF) search strategy are utilized for SIFT feature descriptor matching. Results show high accuracy of our algorithm, even in the circumstance of large translation and large rotation movements.

  15. Calibration of stereo rigs based on the backward projection process

    Science.gov (United States)

    Gu, Feifei; Zhao, Hong; Ma, Yueyang; Bu, Penghui; Zhao, Zixin

    2016-08-01

    High-accuracy 3D measurement based on binocular vision system is heavily dependent on the accurate calibration of two rigidly-fixed cameras. In most traditional calibration methods, stereo parameters are iteratively optimized through the forward imaging process (FIP). However, the results can only guarantee the minimal 2D pixel errors, but not the minimal 3D reconstruction errors. To address this problem, a simple method to calibrate a stereo rig based on the backward projection process (BPP) is proposed. The position of a spatial point can be determined separately from each camera by planar constraints provided by the planar pattern target. Then combined with pre-defined spatial points, intrinsic and extrinsic parameters of the stereo-rig can be optimized by minimizing the total 3D errors of both left and right cameras. An extensive performance study for the method in the presence of image noise and lens distortions is implemented. Experiments conducted on synthetic and real data demonstrate the accuracy and robustness of the proposed method.

  16. Dust Devil in Spirit's View Ahead on Sol 1854 (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11960 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11960 NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,854th Martian day, or sol, of Spirit's surface mission (March 21, 2009). This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 13.79 meters (45 feet) westward earlier on Sol 1854. West is at the center, where a dust devil is visible in the distance. North on the right, where Husband Hill dominates the horizon; Spirit was on top of Husband Hill in September and October 2005. South is on the left, where lighter-toned rock lines the edge of the low plateau called 'Home Plate.' This view is presented as a cylindrical-perspective projection with geometric seam correction.

  17. View Ahead After Spirit's Sol 1861 Drive (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11977 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11977 NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this stereo, 210-degree view of the rover's surroundings during the 1,861st to 1,863rd Martian days, or sols, of Spirit's surface mission (March 28 to 30, 2009). This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The center of the scene is toward the south-southwest. East is on the left. West-northwest is on the right. The rover had driven 22.7 meters (74 feet) southwestward on Sol 1861 before beginning to take the frames in this view. The drive brought Spirit past the northwestern corner of Home Plate. In this view, the western edge of Home Plate is on the portion of the horizon farthest to the left. A mound in middle distance near the center of the view is called 'Tsiolkovsky' and is about 40 meters (about 130 feet) from the rover's position. This view is presented as a cylindrical-perspective projection with geometric seam correction.

  18. Time for a Change; Spirit's View on Sol 1843 (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11973 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11973 NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.' The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate. This view is presented as a cylindrical-perspective projection with geometric seam correction.

  19. Time for a Change; Spirit's View on Sol 1843 (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11973 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11973 NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.' The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate. This view is presented as a cylindrical-perspective projection with geometric seam correction.

  20. Opportunity's View on Sols 1803 and 1804 (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11812 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11812 NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo, full-circle view of the rover's surroundings during the 1,803rd and 1,804th Martian days, or sols, of Opportunity's surface mission (Feb. 18 and 19, 2009). South is at the center; north at both ends. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 55 meters on Sol 1803 before beginning to take the frames in this view. Tracks from that drive recede northward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock. This view is presented as a cylindrical-perspective projection with geometric seam correction.

  1. Development of a stereo camera system for road surface assessment

    Science.gov (United States)

    Su, D.; Nagayama, T.; Irie, M.; Fujino, Y.

    2013-04-01

    In Japan, large number of road structures which were built in the period of high economic growth, has been deteriorated due to heavy traffic and severe conditions, especially in the metropolitan area. In particular, the poor condition of expansion joints of the bridge caused by the frequent impact from the passing vehicles has significantly influence the vehicle safety. In recent year, stereo vision is a widely researched and implemented monitoring approach in object recognition field. This paper introduces the development of a stereo camera system for road surface assessment. In this study, first the static photos taken by a calibrated stereo camera system are utilized to reconstruct the three-dimensional coordinates of targets in the pavement. Subsequently to align the various coordinates obtained from different view meshes, one modified Iterative Closet Point method is proposed by affording the appropriate initial conditions and image correlation method. Several field tests have been carried out to evaluate the capabilities of this system. After succeeding to align all the measured coordinates, this system can offer not only the accurate information of local deficiency such as the patching, crack or pothole, but also global fluctuation in a long distance range of the road surface.

  2. The efficacy of using a personal stereo to treat auditory hallucinations. Preliminary findings.

    Science.gov (United States)

    Johnston, Olwyn; Gallagher, Anthony G; McMahon, Patrick J; King, David J

    2002-09-01

    This article presents preliminary findings from the first participant to complete an experiment assessing the efficacy of the personal stereo in treating auditory hallucinations. O.C., a 50-year-old woman, took part in a controlled treatment trial in which 1-week baseline, personal stereo, and control treatment (nonfunctioning hearing aid) stages were alternated for 7 weeks. The Positive and Negative Syndrome Scale, Clinical Global Impression Scales, Beliefs About Voices Questionnaire, Rosenberg Self-Esteem Scale, and Topography of Voices Rating Scale were used. The personal stereo led to a decrease in the severity of O.C.'s auditory hallucinations. For example, she rated her voices as being fairly distressing during baseline and control treatment stages but neutral during personal stereo stages. A slight decrease in other psychopathology also occurred during personal stereo stages. Use of the personal stereo did not lead to a decrease in self-esteem, contradicting suggestions that counterstimulation treatments for auditory hallucinations may be disempowering.

  3. Interactive stereo electron microscopy enhanced with virtual reality

    Energy Technology Data Exchange (ETDEWEB)

    Bethel, E.Wes; Bastacky, S.Jacob; Schwartz, Kenneth S.

    2001-12-17

    An analytical system is presented that is used to take measurements of objects perceived in stereo image pairs obtained from a scanning electron microscope (SEM). Our system operates by presenting a single stereo view that contains stereo image data obtained from the SEM, along with geometric representations of two types of virtual measurement instruments, a ''protractor'' and a ''caliper''. The measurements obtained from this system are an integral part of a medical study evaluating surfactant, a liquid coating the inner surface of the lung which makes possible the process of breathing. Measurements of the curvature and contact angle of submicron diameter droplets of a fluorocarbon deposited on the surface of airways are performed in order to determine surface tension of the air/liquid interface. This approach has been extended to a microscopic level from the techniques of traditional surface science by measuring submicrometer rather than millimeter diameter droplets, as well as the lengths and curvature of cilia responsible for movement of the surfactant, the airway's protective liquid blanket. An earlier implementation of this approach for taking angle measurements from objects perceived in stereo image pairs using a virtual protractor is extended in this paper to include distance measurements and to use a unified view model. The system is built around a unified view model that is derived from microscope-specific parameters, such as focal length, visible area and magnification. The unified view model ensures that the underlying view models and resultant binocular parallax cues are consistent between synthetic and acquired imagery. When the view models are consistent, it is possible to take measurements of features that are not constrained to lie within the projection plane. The system is first calibrated using non-clinical data of known size and resolution. Using the SEM, stereo image pairs of grids and spheres of

  4. 3D computer vision using Point Grey Research stereo vision cameras

    Institute of Scientific and Technical Information of China (English)

    Don Murray; Vlad Tucakov; WEI Xiong

    2008-01-01

    This paper provides an introduction to stereo vision systems designed by point grey research and describes the possible application of these types of systems. The paper presents an overview of stereo vision techniques and outlines the critical aspects of putting together a system that can perform in the real world. It also provides an overview of how the cameras can be used to facilitate stereo research.

  5. Tri-stereo Pleiades images-derived digital surface models for tectonic geomorphology studies

    Science.gov (United States)

    Ferry, Matthieu; Le Roux-Mallouf, Romain; Ritz, Jean-François; Berthet, Théo; Peyret, Michel; Vernant, Philippe; Maréchal, Anaïs; Cattin, Rodolphe; Mazzotti, Stéphane; Poujol, Antoine

    2014-05-01

    Very high resolution digital elevation models are a key component of modern quantitative geomorphology. In parallel to high-precision but time-consuming kinematic GPS and/or total station surveys and dense coverage but expensive LiDAR campaigns, we explore the usability of affordable, flexible, wide coverage digital surface models (DSMs) derived from Pleiades tri-stereo optical images. We present two different approaches to extract DSM from a triplet of images. The first relies on the photogrammetric extraction of 3 DSMs from the 3 possible stereo couples and subsequent merge based on the best correlation score. The second takes advantage of simultaneous correlation over the 3 images to derive a point cloud. We further extract DSM from panchromatic 0.5 m resolution images and multispectral 2 m resolution images to test for correlation and noise and determine optimal correlation window size and achievable resolution. Georeferencing is also assessed by comparing raw coordinates derived from Pleiades Rational Polynomial Coefficients to ground control points. Primary images appear to be referenced within ~15 m over flat areas where parallax is minimal while derived DSMs and associated orthorectified images show a much improved referencing within ~5 m of GCPs. In order to assess the adequacy of Pleiades DSMs for tectonic geomorphology, we present examples from case studies along the Trougout normal fault (Morocco), the Hovd strike-slip fault (Mongolia), the Denali strike-slip fault (USA and Canada) and the Main Frontal Thrust (Bhutan). In addition to proposing a variety of tectonic contexts, these examples cover a wide range of climatic conditions (semi-arid, arctic and tropical), vegetation covers (bare earth, sparse Mediterranean, homogeneous arctic pine, varied tropical forest), lithological natures and related erosion rates. The capacity of derived DSMs is demonstrated to characterize geomorphic markers of active deformation such as marine and alluvial terraces

  6. New Method of Reconstruction from Nonparallel Stereo and Application to Surgical Navigator

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new method to reconstruct 3D scene points from nonparallel stereo is proposed. From a pair of conjugate images in an arbitrarily configured stereo system that has been calibrated, coordinates of 3D scene points can be computed directly using the method, bypassing the process of rectifying images or iterative solution involved in existing methods. Experiment results from both simulated data and real images validate the method. Practical application to surgical navigator shows that the method has advantages to improve efficiency and accuracy of 3D reconstruction from nonparallel stereo system in comparison with the conventional method that employs algorithm for standard parallel axes stereo geometry.

  7. Stereo Vision-Based High Dynamic Range Imaging Using Differently-Exposed Image Pair

    Science.gov (United States)

    Park, Won-Jae; Ji, Seo-Won; Kang, Seok-Jae; Jung, Seung-Won; Ko, Sung-Jea

    2017-01-01

    In this paper, a high dynamic range (HDR) imaging method based on the stereo vision system is presented. The proposed method uses differently exposed low dynamic range (LDR) images captured from a stereo camera. The stereo LDR images are first converted to initial stereo HDR images using the inverse camera response function estimated from the LDR images. However, due to the limited dynamic range of the stereo LDR camera, the radiance values in under/over-exposed regions of the initial main-view (MV) HDR image can be lost. To restore these radiance values, the proposed stereo matching and hole-filling algorithms are applied to the stereo HDR images. Specifically, the auxiliary-view (AV) HDR image is warped by using the estimated disparity between initial the stereo HDR images and then effective hole-filling is applied to the warped AV HDR image. To reconstruct the final MV HDR, the warped and hole-filled AV HDR image is fused with the initial MV HDR image using the weight map. The experimental results demonstrate objectively and subjectively that the proposed stereo HDR imaging method provides better performance compared to the conventional method. PMID:28640235

  8. Stereo Vision-Based High Dynamic Range Imaging Using Differently-Exposed Image Pair

    Directory of Open Access Journals (Sweden)

    Won-Jae Park

    2017-06-01

    Full Text Available In this paper, a high dynamic range (HDR imaging method based on the stereo vision system is presented. The proposed method uses differently exposed low dynamic range (LDR images captured from a stereo camera. The stereo LDR images are first converted to initial stereo HDR images using the inverse camera response function estimated from the LDR images. However, due to the limited dynamic range of the stereo LDR camera, the radiance values in under/over-exposed regions of the initial main-view (MV HDR image can be lost. To restore these radiance values, the proposed stereo matching and hole-filling algorithms are applied to the stereo HDR images. Specifically, the auxiliary-view (AV HDR image is warped by using the estimated disparity between initial the stereo HDR images and then effective hole-filling is applied to the warped AV HDR image. To reconstruct the final MV HDR, the warped and hole-filled AV HDR image is fused with the initial MV HDR image using the weight map. The experimental results demonstrate objectively and subjectively that the proposed stereo HDR imaging method provides better performance compared to the conventional method.

  9. On the Benefits of Stereo Graphics in Virtual Obstacle Avoidance Tasks

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas; Stenholt, Rasmus

    2014-01-01

    of an experiment to see if stereo makes any quantifiable, statistically significant difference in the ability to avoid collisions with virtual obstacles while navigating a 3-D space under constant acceleration. Our results indicate that for this particular application scenario, stereo does provide a significant......In virtual reality, stereo graphics is a very common way of increasing the level of perceptual realism in the visual part of the experience. However, stereo graphics comes at cost, both in technical terms and from a user perspective. In this paper, we present the preliminary results...

  10. Neutrino Oscillations in Dense Matter

    Science.gov (United States)

    Lobanov, A. E.

    2017-03-01

    A modification of the electroweak theory, where the fermions with the same electroweak quantum numbers are combined in multiplets and are treated as different quantum states of a single particle, is proposed. In this model, mixing and oscillations of particles arise as a direct consequence of the general principles of quantum field theory. The developed approach enables one to calculate the probabilities of the processes taking place in the detector at long distances from the particle source. Calculations of higher-order processes, including computation of the contributions due to radiative corrections, can be performed in the framework of the perturbation theory using the regular diagram technique. As a result, the analog to the Dirac-Schwinger equation of quantum electrodynamics describing neutrino oscillations and its spin rotation in dense matter can be obtained.

  11. DPIS for warm dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, K.; Kanesue, T.; Horioka, K.; Okamura, M.

    2010-05-23

    Warm Dense Matter (WDM) offers an challenging problem because WDM, which is beyond ideal plasma, is in a low temperature and high density state with partially degenerate electrons and coupled ions. WDM is a common state of matter in astrophysical objects such as cores of giant planets and white dwarfs. The WDM studies require large energy deposition into a small target volume in a shorter time than the hydrodynamical time and need uniformity across the full thickness of the target. Since moderate energy ion beams ({approx} 0.3 MeV/u) can be useful tool for WDM physics, we propose WDM generation using Direct Plasma Injection Scheme (DPIS). In the DPIS, laser ion source is connected to the Radio Frequency Quadrupole (RFQ) linear accelerator directly without the beam transport line. DPIS with a realistic final focus and a linear accelerator can produce WDM.

  12. 高分辨率卫星立体影像对的图割匹配算法%Stereo matching algorithm based on improved graph cuts for high spatial resolution satellite stereo pair

    Institute of Scientific and Technical Information of China (English)

    王瑞瑞; 石伟; 黄华国

    2013-01-01

    针对高分辨率卫星立体像对自动匹配中同名特征点难以选取,导致视差图较低的问题,引入在计算机领域取得成功应用的图割匹配算法,将立体匹配问题转换为全局能量函数的最小化问题,并进行改进,构建简化的网络求解最小割,实现能量函数的最小化,得到较为准确的视差图,实现卫星立体像对的匹配。该文选取EROS-B卫星立体像对进行试验,结果证明改进的图割立体匹配算法生成视差图的均方根误差是传统基于相关系数的区域匹配算法生成视差图的均方根误差的1/3,且算法运行时间比传统的图割立体匹配算法的运行时间缩短了85.2%。该研究可为基于卫星立体像对构建高精度数字高程模型提供前提条件。%Many objects have clear contour and texture in the high spatial resolution satellite stereo pair. Due to the elevation differences in many objects, and the existence of building shades, and the similar objects, and so on, the extraction of corresponding feature points from the high spatial resolution satellite stereo pair is difficult, which leads to a rough disparity map. Aiming at the problem, the graph cuts algorithm, which has a successful application in the computer vision field, was introduced and improved for the stereo matching. The core problem of stereo matching is to compute the optimal disparity value. Based on this rule, the graph cuts constructs the global energy function by using the disparity value of all the pixels, and transforms the problem of stereo matching to the problem of minimization of the global energy function. However, there are two problems existing in the process of stereo matching by using the traditional graph cuts for the high-resolution satellite stereo pair. The first one is that the time complexity is high; the other one is that the disparity map has a lower precision. Aiming to the aforementioned two problems, the graph cuts

  13. Correspondence Search Mitigation Using Feature Space Anti-Aliasing

    Science.gov (United States)

    2007-01-01

    of inertial sensors and optical imagers, aided by the continuing improvement in microprocessor technology, motivates us to consider using inertial...Vision, 60(2):91–110, 2004. [12] B. D. Lucas and T. Kanade. An iterative image regis- tration technique with an application to stereo vision. Proc...Springer-Verlag, Inc., New York, New York, 2004. [14] Clark F. Olson, Larry H. Matthies, Marcel Schoppers, and Mark W. Maimone. Robust stereo ego-motion

  14. AN AERIAL-IMAGE DENSE MATCHING APPROACH BASED ON OPTICAL FLOW FIELD

    Directory of Open Access Journals (Sweden)

    W. Yuan

    2016-06-01

    Full Text Available Dense matching plays an important role in many fields, such as DEM (digital evaluation model producing, robot navigation and 3D environment reconstruction. Traditional approaches may meet the demand of accuracy. But the calculation time and out puts density is hardly be accepted. Focus on the matching efficiency and complex terrain surface matching feasibility an aerial image dense matching method based on optical flow field is proposed in this paper. First, some high accurate and uniformed control points are extracted by using the feature based matching method. Then the optical flow is calculated by using these control points, so as to determine the similar region between two images. Second, the optical flow field is interpolated by using the multi-level B-spline interpolation in the similar region and accomplished the pixel by pixel coarse matching. Final, the results related to the coarse matching refinement based on the combined constraint, which recognizes the same points between images. The experimental results have shown that our method can achieve per-pixel dense matching points, the matching accuracy achieves sub-pixel level, and fully meet the three-dimensional reconstruction and automatic generation of DSM-intensive matching’s requirements. The comparison experiments demonstrated that our approach’s matching efficiency is higher than semi-global matching (SGM and Patch-based multi-view stereo matching (PMVS which verifies the feasibility and effectiveness of the algorithm.

  15. MobileFusion: real-time volumetric surface reconstruction and dense tracking on mobile phones.

    Science.gov (United States)

    Ondrúška, Peter; Kohli, Pushmeet; Izadi, Shahram

    2015-11-01

    We present the first pipeline for real-time volumetric surface reconstruction and dense 6DoF camera tracking running purely on standard, off-the-shelf mobile phones. Using only the embedded RGB camera, our system allows users to scan objects of varying shape, size, and appearance in seconds, with real-time feedback during the capture process. Unlike existing state of the art methods, which produce only point-based 3D models on the phone, or require cloud-based processing, our hybrid GPU/CPU pipeline is unique in that it creates a connected 3D surface model directly on the device at 25Hz. In each frame, we perform dense 6DoF tracking, which continuously registers the RGB input to the incrementally built 3D model, minimizing a noise aware photoconsistency error metric. This is followed by efficient key-frame selection, and dense per-frame stereo matching. These depth maps are fused volumetrically using a method akin to KinectFusion, producing compelling surface models. For each frame, the implicit surface is extracted for live user feedback and pose estimation. We demonstrate scans of a variety of objects, and compare to a Kinect-based baseline, showing on average ∼ 1.5cm error. We qualitatively compare to a state of the art point-based mobile phone method, demonstrating an order of magnitude faster scanning times, and fully connected surface models.

  16. An Aerial-Image Dense Matching Approach Based on Optical Flow Field

    Science.gov (United States)

    Yuan, Wei; Chen, Shiyu; Zhang, Yong; Gong, Jianya; Shibasaki, Ryosuke

    2016-06-01

    Dense matching plays an important role in many fields, such as DEM (digital evaluation model) producing, robot navigation and 3D environment reconstruction. Traditional approaches may meet the demand of accuracy. But the calculation time and out puts density is hardly be accepted. Focus on the matching efficiency and complex terrain surface matching feasibility an aerial image dense matching method based on optical flow field is proposed in this paper. First, some high accurate and uniformed control points are extracted by using the feature based matching method. Then the optical flow is calculated by using these control points, so as to determine the similar region between two images. Second, the optical flow field is interpolated by using the multi-level B-spline interpolation in the similar region and accomplished the pixel by pixel coarse matching. Final, the results related to the coarse matching refinement based on the combined constraint, which recognizes the same points between images. The experimental results have shown that our method can achieve per-pixel dense matching points, the matching accuracy achieves sub-pixel level, and fully meet the three-dimensional reconstruction and automatic generation of DSM-intensive matching's requirements. The comparison experiments demonstrated that our approach's matching efficiency is higher than semi-global matching (SGM) and Patch-based multi-view stereo matching (PMVS) which verifies the feasibility and effectiveness of the algorithm.

  17. Emission Spectroscopy of the Interior of Optically Dense Post-Detonation Fireballs

    Science.gov (United States)

    2013-03-01

    TP-2013-011 Emission Spectroscopy of the Interior of Optically Dense Post-Detonation Fireballs Distribution A: Approved for public release...Detonation Fireballs 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62102F 6. AUTHOR(S) W.K. Lewis1, C.G. Rumchik2, M.J...detonation fireballs that form as under- oxidized detonation products burn in the surrounding air are optically dense and the corresponding emission

  18. i-BRUSH: a gaze-contingent virtual paintbrush for dense 3D reconstruction in robotic assisted surgery.

    Science.gov (United States)

    Visentini-Scarzanella, Marco; Mylonas, George P; Stoyanov, Danail; Yang, Guang-Zhong

    2009-01-01

    With increasing demand on intra-operative navigation and motion compensation during robotic assisted minimally invasive surgery, real-time 3D deformation recovery remains a central problem. Currently the majority of existing methods rely on salient features, where the inherent paucity of distinctive landmarks implies either a semi-dense reconstruction or the use of strong geometrical constraints. In this study, we propose a gaze-contingent depth reconstruction scheme by integrating human perception with semi-dense stereo and p-q based shading information. Depth inference is carried out in real-time through a novel application of Bayesian chains without smoothness priors. The practical value of the scheme is highlighted by detailed validation using a beating heart phantom model with known geometry to verify the performance of gaze-contingent 3D surface reconstruction and deformation recovery.

  19. Optimization of Camera Arrangement Using Correspondence Field to Improve Depth Estimation.

    Science.gov (United States)

    Fu, Shichao; Safaei, Farzad; Li, Wanqing

    2017-04-18

    Stereo matching algorithms attempt to estimate depth from the images obtained by two cameras. In most cases, the arrangement of cameras (their locations and orientations with respect to the scene) are determined based on human experience. In this paper, it is shown that the camera arrangement can be optimized using the concept of correspondence field (CF) for better acquisition of depth. Specifically, the paper demonstrates the relationship between the correspondence field of a pair of cameras and depth estimation accuracy and presents a method to optimize their arrangement based on the gradient of CF. The experimental results show that a pair of cameras optimized by the proposed method can improve the accuracy of depth estimation by as much as 30% compared to the conventional camera arrangements.

  20. 5G Ultra-Dense Cellular Networks

    OpenAIRE

    Ge, Xiaohu; Tu, Song; Mao, Guoqiang; Wang, Cheng-xiang; Han, Tao

    2015-01-01

    Traditional ultra-dense wireless networks are recommended as a complement for cellular networks and are deployed in partial areas, such as hotspot and indoor scenarios. Based on the massive multiple-input multi-output (MIMO) antennas and the millimeter wavecommunication technologies, the 5G ultra-dense cellular network is proposed to deploy in overall cellular scenarios. Moreover, a distribution network architecture is presented for 5G ultra-dense cellular networks. Furthermore, the backhaul ...

  1. Interference Coordination for Dense Wireless Networks

    DEFF Research Database (Denmark)

    Soret, Beatriz; Pedersen, Klaus I.; Jørgensen, Niels T.K.

    2015-01-01

    The promise of ubiquitous and super-fast connectivity for the upcoming years will be in large part fulfilled by the addition of base stations and spectral aggregation. The resulting very dense networks (DenseNets) will face a number of technical challenges. Among others, the interference emerges ...... simply react to an identified interference problem. As an example, we propose two algorithms to apply time domain and frequency domain small cell interference coordination in a DenseNet....

  2. HOW GOOD IS A DENSE SHOP SCHEDULE?

    Institute of Scientific and Technical Information of China (English)

    陈礴; 俞文(鱼此)

    2001-01-01

    In this paper, we study a class of simple and easy-to-construct shop schedules, known as dense schedules. We present tight bounds on the maximum deviation in makespan of dense flow-shop and job-shop schedules from their optimal ones. For dense open-shop schedules, we do the same for the special case of four machines and thus add a stronger supporting case for proving a standing conjecture.

  3. Breaking Dense Structures: Proving Stability of Densely Structured Hybrid Systems

    Directory of Open Access Journals (Sweden)

    Eike Möhlmann

    2015-06-01

    Full Text Available Abstraction and refinement is widely used in software development. Such techniques are valuable since they allow to handle even more complex systems. One key point is the ability to decompose a large system into subsystems, analyze those subsystems and deduce properties of the larger system. As cyber-physical systems tend to become more and more complex, such techniques become more appealing. In 2009, Oehlerking and Theel presented a (de-composition technique for hybrid systems. This technique is graph-based and constructs a Lyapunov function for hybrid systems having a complex discrete state space. The technique consists of (1 decomposing the underlying graph of the hybrid system into subgraphs, (2 computing multiple local Lyapunov functions for the subgraphs, and finally (3 composing the local Lyapunov functions into a piecewise Lyapunov function. A Lyapunov function can serve multiple purposes, e.g., it certifies stability or termination of a system or allows to construct invariant sets, which in turn may be used to certify safety and security. In this paper, we propose an improvement to the decomposing technique, which relaxes the graph structure before applying the decomposition technique. Our relaxation significantly reduces the connectivity of the graph by exploiting super-dense switching. The relaxation makes the decomposition technique more efficient on one hand and on the other allows to decompose a wider range of graph structures.

  4. Dense graphlet statistics of protein interaction and random networks.

    Science.gov (United States)

    Colak, R; Hormozdiari, F; Moser, F; Schönhuth, A; Holman, J; Ester, M; Sahinalp, S C

    2009-01-01

    Understanding evolutionary dynamics from a systemic point of view crucially depends on knowledge about how evolution affects size and structure of the organisms' functional building blocks (modules). It has been recently reported that statistics over sparse PPI graphlets can robustly monitor such evolutionary changes. However, there is abundant evidence that in PPI networks modules can be identified with highly interconnected (dense) and/or bipartite subgraphs. We count such dense graphlets in PPI networks by employing recently developed search strategies that render related inference problems tractable. We demonstrate that corresponding counting statistics differ significantly between prokaryotes and eukaryotes as well as between "real" PPI networks and scale free network emulators. We also prove that another class of emulators, the low-dimensional geometric random graphs (GRGs) cannot contain a specific type of motifs, complete bipartite graphs, which are abundant in PPI networks.

  5. ANN implementation of stereo vision using a multi-layer feedback architecture

    Energy Technology Data Exchange (ETDEWEB)

    Mousavi, M.S.; Schalkoff, R.J. [Clemson Univ., Clemson, SC (United States)

    1994-08-01

    An Artificial Neural Network (ANN), consisting of three interacting neural modules, is developed for stereo vision. The first module locates sharp intensity changes in each of the images. The edge detection process is basically a bottom-up, one-to-one input-output mapping process with a network structure which is time-invariant. In the second module, a multilayered connectionist network is used to extract the features or primitives for disparity analysis (matching). A similarity measure is defined and computed for each pair of primitive matches and is passed to the third module. The third module solves the difficult correspondence problem by mapping it into a constraint satisfaction problem. Intra- and inter-scanline constraints are used in order to restrict possible feature matches. The inter-scanline constraints are implemented via interconnections of a three-dimensional neural network. The overall process is iterative. At the end of each network iteration, the output of the third constraint satisfaction module feeds back updated information on matching pairs as well as their corresponding location in the left and right images to the input of the second module. This iterative process continues until the output of the third module converges to an stable state. Once the matching process is completed, the disparity can be calculated, and camera calibration parameters can be used to find the three-dimensional location of object points. Results using this computational architecture are shown. 26 refs.

  6. Z-Earth: 4D topography from space combining short-baseline stereo and lidar

    Science.gov (United States)

    Dewez, T. J.; Akkari, H.; Kaab, A. M.; Lamare, M. L.; Doyon, G.; Costeraste, J.

    2013-12-01

    The advent of free-of-charge global topographic data sets SRTM and Aster GDEM have enabled testing a host of geoscience hypotheses. Availability of such data is now considered standard, and though resolved at 30-m to 90-m pixel size, they are today regarded as obsolete and inappropriate given the regularly updated sub-meter imagery coming through web services like Google Earth. Two features will thus help meet the current topographic data needs of the Geoscience communities: field-scale-compatible elevation datasets (i.e. meter-scale digital models and sub-meter elevation precision) and provision for regularly updated topography to tackle earth surface changes in 4D, while retaining the key for success: data availability at no charge. A new space borne instrumental concept called Z-Earth has undergone phase 0 study at CNES, the French space agency to fulfill these aims. The scientific communities backing this proposal are that of natural hazards, glaciology and biomass. The system under study combines a short-baseline native stereo imager and a lidar profiler. This combination provides spatially resolved elevation swaths together with absolute along-track elevation control point profiles. Acquisition is designed for revisit time better than a year. Intended products not only target single pass digital surface models, color orthoimages and small footprint full-wave-form lidar profiles to update existing topographic coverage, but also time series of them. 3D change detection targets centimetre-scale horizontal precision and metric vertical precision, in complement of -now traditional- spectral change detection. To assess the actual concept value, two real-size experiments were carried out. We used sub-meter-scale Pleiades panchromatic stereo-images to generate digital surface models and check them against dense airborne lidar coverages, one heliborne set purposely flown in Corsica (50-100pts/sq.m) and a second one retrieved from OpenTopography.org (~10pts/sq.m.). In

  7. Stereo Matching of Planar Curves Composed of Time Stamped Points

    Institute of Scientific and Technical Information of China (English)

    Wang Shuwen; Zhang Tianxu

    2006-01-01

    Matching features such as curve segments in stereo images play a very important role in scene reconstruction. In this paper, a stereo matching algorithm for the trajectories composed of time stamped points is proposed. Based on time stamped points, planar curve match measurements are given first, such as time constraint, cross-ratio invariant constraint and epipolar geometry constraint;then, a trajectory matching method is proposed based on epipolar geometry constraint and cross-ratio invariant constraint. In order to match the planar curve segments projected by perspective projection system, the curve start time and end time are selected first to prepare match candidates. Then, the epipolar equation is used to discard the unmatched curve segment candidates. At last, a cross ratio invariant constraint is used to find the most matched curve segments. If their match measurement is higher than the specialized threshold, a candidate with the least cross ratio difference is then selected as the match result; otherwise, no match is found. Unlike the conventional planar curve segments matching algorithm, this paper presents a weakly calibrated binocular stereo vision system which is based on wide baseline. The stamped points are obtained by targets detecting method of flying objects from image sequences.Due to wide baseline, there must exist the projection not in epipolar monotonic order or the curve segments located in very short distance and keeping the epipolar monotonic order. By using the method mentioned above, experiments are made to match planar curve segments not only in epipolar monotonic order but also not in epipolar monotonic order. The results show that the performance of our curve matching algorithm is effective for matching the arc-like planar trajectories composed of time stamped points.

  8. Spirit's View Beside 'Home Plate' on Sol 1823 (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11971 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11971 NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,823rd Martian day, or sol, of Spirit's surface mission (Feb. 17, 2009). This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The center of the view is toward the south-southwest. The rover had driven 7 meters (23 feet) eastward earlier on Sol 1823, part of maneuvering to get Spirit into a favorable position for climbing onto the low plateau called 'Home Plate.' However, after two driving attempts with negligible progress during the following three sols, the rover team changed its strategy for getting to destinations south of Home Plate. The team decided to drive Spirit at least partway around Home Plate, instead of ascending the northern edge and taking a shorter route across the top of the plateau. Layered rocks forming part of the northern edge of Home Plate can be seen near the center of the image. Rover wheel tracks are visible at the lower edge. This view is presented as a cylindrical-perspective projection with geometric seam correction.

  9. New Record Five-Wheel Drive, Spirit's Sol 1856 (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11962 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11962 NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,856th Martian day, or sol, of Spirit's surface mission (March 23, 2009). The center of the view is toward the west-southwest. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 25.82 meters (84.7 feet) west-northwestward earlier on Sol 1856. This is the longest drive on Mars so far by a rover using only five wheels. Spirit lost the use of its right-front wheel in March 2006. Before Sol 1856, the farthest Spirit had covered in a single sol's five-wheel drive was 24.83 meters (81.5 feet), on Sol 1363 (Nov. 3, 2007). The Sol 1856 drive made progress on a route planned for taking Spirit around the western side of the low plateau called 'Home Plate.' A portion of the northwestern edge of Home Plate is prominent in the left quarter of this image, toward the south. This view is presented as a cylindrical-perspective projection with geometric seam correction.

  10. Rock Moved by Mars Lander Arm, Stereo View

    Science.gov (United States)

    2008-01-01

    The robotic arm on NASA's Phoenix Mars Lander slid a rock out of the way during the mission's 117th Martian day (Sept. 22, 2008) to gain access to soil that had been underneath the rock.The lander's Surface Stereo Imager took the two images for this stereo view later the same day, showing the rock, called 'Headless,' after the arm pushed it about 40 centimeters (16 inches) from its previous location. 'The rock ended up exactly where we intended it to,' said Matt Robinson of NASA's Jet Propulsion Laboratory, robotic arm flight software lead for the Phoenix team. The arm had enlarged the trench near Headless two days earlier in preparation for sliding the rock into the trench. The trench was dug to about 3 centimeters (1.2 inches) deep. The ground surface between the rock's prior position and the lip of the trench had a slope of about 3 degrees downward toward the trench. Headless is about the size and shape of a VHS videotape. The Phoenix science team sought to move the rock in order to study the soil and the depth to subsurface ice underneath where the rock had been. This left-eye and right-eye images for this stereo view were taken at about 12:30 p.m., local solar time on Mars. The scene appears three-dimensional when seen through blue-red glasses.The view is to the north northeast of the lander. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

  11. Spirit's View Beside 'Home Plate' on Sol 1823 (Stereo)

    Science.gov (United States)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11971 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11971 NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,823rd Martian day, or sol, of Spirit's surface mission (Feb. 17, 2009). This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The center of the view is toward the south-southwest. The rover had driven 7 meters (23 feet) eastward earlier on Sol 1823, part of maneuvering to get Spirit into a favorable position for climbing onto the low plateau called 'Home Plate.' However, after two driving attempts with negligible progress during the following three sols, the rover team changed its strategy for getting to destinations south of Home Plate. The team decided to drive Spirit at least partway around Home Plate, instead of ascending the northern edge and taking a shorter route across the top of the plateau. Layered rocks forming part of the northern edge of Home Plate can be seen near the center of the image. Rover wheel tracks are visible at the lower edge. This view is presented as a cylindrical-perspective projection with geometric seam correction.

  12. Stereo-photometric techniques for scanning micrometer scale

    Directory of Open Access Journals (Sweden)

    Rocio Cachero

    2015-11-01

    Full Text Available This paper describes a new methodology based on the combination of photogrammetric and stereo-photometric techniques that allows creating virtual replicas reproducing the relief in micrometric scale, with a geometric resolution until 7 microns. The finest details of the texture obtained by photogrammetric methods are translated to the relief of the mesh to provide quality 3D printing by additive manufacturing methods. These results open new possibilities for virtual and physical reproduction of archeological items that need a great accuracy and geometric resolution.

  13. Multiview specular stereo reconstruction of large mirror surfaces

    KAUST Repository

    Balzer, Jonathan

    2011-06-01

    In deflectometry, the shape of mirror objects is recovered from distorted images of a calibrated scene. While remarkably high accuracies are achievable, state-of-the-art methods suffer from two distinct weaknesses: First, for mainly constructive reasons, these can only capture a few square centimeters of surface area at once. Second, reconstructions are ambiguous i.e. infinitely many surfaces lead to the same visual impression. We resolve both of these problems by introducing the first multiview specular stereo approach, which jointly evaluates a series of overlapping deflectometric images. Two publicly available benchmarks accompany this paper, enabling us to numerically demonstrate viability and practicability of our approach. © 2011 IEEE.

  14. Pedestrian Counting with Occlusion Handling Using Stereo Thermal Cameras

    DEFF Research Database (Denmark)

    Kristoffersen, Miklas Strøm; Dueholm, Jacob Velling; Gade, Rikke

    2016-01-01

    and the complexity of scenes with many people occluding one another. To address these challenges, this paper introduces the use of a stereo thermal camera setup for pedestrian counting. We investigate the reconstruction of 3D points in a pedestrian street with two thermal cameras and propose an algorithm...... for pedestrian counting based on clustering and tracking of the 3D point clouds. The method is tested on two five-minute video sequences captured at a public event with a moderate density of pedestrians and heavy occlusions. The counting performance is compared to the manually annotated ground truth and shows...

  15. Trigger and readout electronics for the STEREO experiment

    CERN Document Server

    Bourrion, O; Bouvier, J; Vescovi, C; Bosson, G; Helaine, V; Lamblin, J; Li, C; Montanet, F; Real, J S; Salagnac, T; Ponchant, N; Stutz, A; Tourres, D; Zsoldos, S

    2015-01-01

    The STEREO experiment will search for a sterile neutrino by measuring the anti-neutrino energy spectrum as a function of the distance from the source, the ILL nuclear reactor. A dedicated electronic, hosted in a single microTCA crate, was designed for this experiment. It performs triggering in two stages with various selectable conditions, processing and readout via UDP/IPBUS on 68 photomultiplier signals continuously digitized at 250 MSPS. Additionally, for detector performance monitoring, the electronics allow on-line calibration by driving LED synchronously with the data acquisition. This paper describes the electronics requirements, architecture and the performances achieved.

  16. 3D Stereo Visualization for Mobile Robot Tele-Guide

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2006-01-01

    The use of 3D stereoscopic visualization may provide a user with higher comprehension of remote environments in tele-operation when compared to 2D viewing. In particular, a higher perception of environment depth characteristics, spatial localization, remote ambient layout, as well as faster system...... learning and decision performance. Works in the literature have demonstrated how stereo vision contributes to improve perception of some depth cues often for abstract tasks, while little can be found about the advantages of stereoscopic visualization in mobile robot tele-guide applications. This work...

  17. 3D Stereo Visualization for Mobile Robot Tele-Guide

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2006-01-01

    learning and decision performance. Works in the literature have demonstrated how stereo vision contributes to improve perception of some depth cues often for abstract tasks, while little can be found about the advantages of stereoscopic visualization in mobile robot tele-guide applications. This work...... technologies. In particular, experiments were carried out on different virtual reality (VR) systems having different characteristics both in terms of sense of presence and interaction capabilities provided to a user, as well as cost and portability. Results from a set of test trials ran on five VR systems...

  18. Optimization on shape curves with application to specular stereo

    KAUST Repository

    Balzer, Jonathan

    2010-01-01

    We state that a one-dimensional manifold of shapes in 3-space can be modeled by a level set function. Finding a minimizer of an independent functional among all points on such a shape curve has interesting applications in computer vision. It is shown how to replace the commonly encountered practice of gradient projection by a projection onto the curve itself. The outcome is an algorithm for constrained optimization, which, as we demonstrate theoretically and numerically, provides some important benefits in stereo reconstruction of specular surfaces. © 2010 Springer-Verlag.

  19. Stereo optical guidance system for control of industrial robots

    Science.gov (United States)

    Powell, Bradley W. (Inventor); Rodgers, Mike H. (Inventor)

    1992-01-01

    A device for the generation of basic electrical signals which are supplied to a computerized processing complex for the operation of industrial robots. The system includes a stereo mirror arrangement for the projection of views from opposite sides of a visible indicia formed on a workpiece. The views are projected onto independent halves of the retina of a single camera. The camera retina is of the CCD (charge-coupled-device) type and is therefore capable of providing signals in response to the image projected thereupon. These signals are then processed for control of industrial robots or similar devices.

  20. Picture Collage with Genetic Algorithm and Stereo vision

    Directory of Open Access Journals (Sweden)

    Hesam Ekhtiyar

    2011-09-01

    Full Text Available In this paper, a salient region extraction method for creating picture collage based on stereo vision is proposed. Picture collage is a kind of visual image summary to arrange all input images on a given canvas, allowing overlay, to maximize visible visual information. The salient regions of each image are firstly extracted and represented as a depth map. The output picture collage shows as many visible salient regions (without being overlaid by others from all images as possible. A very efficient Genetic algorithm is used here for the optimization. The experimental results showed the superior performance of the proposed method.

  1. Application of stereo photogrammetric techniques for measuring African Elephants

    Directory of Open Access Journals (Sweden)

    A. J Hall-Martin

    1979-01-01

    Full Text Available Measurements of shoulder height and back length of African elephants were obtained by means of stereo photogrammetric techniques. A pair of Zeiss UMK 10/1318 cameras, mounted on a steel frame on the back of a vehicle, were used to photograph the elephants in the Addo Elephant National Park, Republic of South Africa. Several modifications of normal photogrammetry procedure applicable to the field situation (eg. control points and the computation of results (eg. relative orientation are briefly mentioned. Six elephants were immobilised after being photographed and the measurements obtained from them agreed within a range of 1 cm-10 cm with the photogrammetric measurements.

  2. Viking image processing. [digital stereo imagery and computer mosaicking

    Science.gov (United States)

    Green, W. B.

    1977-01-01

    The paper discusses the camera systems capable of recording black and white and color imagery developed for the Viking Lander imaging experiment. Each Viking Lander image consisted of a matrix of numbers with 512 rows and an arbitrary number of columns up to a maximum of about 9,000. Various techniques were used in the processing of the Viking Lander images, including: (1) digital geometric transformation, (2) the processing of stereo imagery to produce three-dimensional terrain maps, and (3) computer mosaicking of distinct processed images. A series of Viking Lander images is included.

  3. The development of radiation hardened robot for nuclear facility - Stereo cursor generation and a development of object distance information extracting technique

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sang Ho; Sohng, In Tae [Inje University, Pusan (Korea); Kwon, Ki Ku [Kyungpook National University, Taegu (Korea)

    2000-03-01

    An object distance information extractor using stereo cursor in stereo imaging system is developed and implemented. The stereo cursor is overlaid on a stereoscopic video image, and is controlled by three dimensional joystick. The depth of stereo cursor is controlled by adjusting disparity of the stereo cursor. A stereo object can be selected by placing the stereo cursor at all point in image. The object distance is inversely proportional to disparity of the cursor. By measuring the amount disparity of stereo cursor, therefore, we can estimate the object distance simultaneously. The object distance is displayed to 7-segment LED by a lookup table method. 17 refs., 40 figs., 2 tabs. (Author)

  4. A Multi-View Dense Image Matching Method for High-Resolution Aerial Imagery Based on a Graph Network

    Directory of Open Access Journals (Sweden)

    Li Yan

    2016-09-01

    Full Text Available Multi-view dense matching is a crucial process in automatic 3D reconstruction and mapping applications. In this paper, we present a robust and effective multi-view dense matching algorithm for high-resolution aerial images based on a graph network. The overlap ratio and intersection angle between image pairs are used to find candidate stereo pairs and build the graph network. A Coarse-to-Fine strategy based on an improved Semi-Global Matching algorithm is applied for disparity computation across stereo pairs. Based on the constructed graph, point clouds of base views are generated by triangulating all connected image nodes, followed by a fusion process with the average reprojection error as a priority measure. The proposed method was successfully applied in experiments on aerial image test dataset provided by the ISPRS of Vaihingen, Germany and an oblique nadir image block of Zürich, Switzerland, using three kinds of matching configurations. The proposed method was compared to other state-of-art methods, SURE and PhotoScan. The results demonstrate that the proposed method delivers matches at higher completeness, efficiency, and accuracy than the other methods tested; the RMS for average reprojection error reached the sub pixel level and the actual positioning deviation was better than 1.5 GSD.

  5. Generalized Green Correspondence of Graded Modules

    Institute of Scientific and Technical Information of China (English)

    Salah El-Din; S.HUSSEIN

    2009-01-01

    The author studies the Green correspondence and quasi-Green correspondence for indecomposable modules over strongly graded rings.The motivation is to investigate the influence of induction and restriction processes on indecomposability of graded modules.

  6. Optimal probabilistic dense coding schemes

    Science.gov (United States)

    Kögler, Roger A.; Neves, Leonardo

    2017-04-01

    Dense coding with non-maximally entangled states has been investigated in many different scenarios. We revisit this problem for protocols adopting the standard encoding scheme. In this case, the set of possible classical messages cannot be perfectly distinguished due to the non-orthogonality of the quantum states carrying them. So far, the decoding process has been approached in two ways: (i) The message is always inferred, but with an associated (minimum) error; (ii) the message is inferred without error, but only sometimes; in case of failure, nothing else is done. Here, we generalize on these approaches and propose novel optimal probabilistic decoding schemes. The first uses quantum-state separation to increase the distinguishability of the messages with an optimal success probability. This scheme is shown to include (i) and (ii) as special cases and continuously interpolate between them, which enables the decoder to trade-off between the level of confidence desired to identify the received messages and the success probability for doing so. The second scheme, called multistage decoding, applies only for qudits ( d-level quantum systems with d>2) and consists of further attempts in the state identification process in case of failure in the first one. We show that this scheme is advantageous over (ii) as it increases the mutual information between the sender and receiver.

  7. STAR FORMATION IN DENSE CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Philip C., E-mail: pmyers@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2011-12-10

    A model of core-clump accretion with equally likely stopping describes star formation in the dense parts of clusters, where models of isolated collapsing cores may not apply. Each core accretes at a constant rate onto its protostar, while the surrounding clump gas accretes as a power of protostar mass. Short accretion flows resemble Shu accretion and make low-mass stars. Long flows resemble reduced Bondi accretion and make massive stars. Accretion stops due to environmental processes of dynamical ejection, gravitational competition, and gas dispersal by stellar feedback, independent of initial core structure. The model matches the field star initial mass function (IMF) from 0.01 to more than 10 solar masses. The core accretion rate and the mean accretion duration set the peak of the IMF, independent of the local Jeans mass. Massive protostars require the longest accretion durations, up to 0.5 Myr. The maximum protostar luminosity in a cluster indicates the mass and age of its oldest protostar. The distribution of protostar luminosities matches those in active star-forming regions if protostars have a constant birthrate but not if their births are coeval. For constant birthrate, the ratio of young stellar objects to protostars indicates the star-forming age of a cluster, typically {approx}1 Myr. The protostar accretion luminosity is typically less than its steady spherical value by a factor of {approx}2, consistent with models of episodic disk accretion.

  8. Star formation in dense clusters

    CERN Document Server

    Myers, Philip C

    2011-01-01

    A model of core-clump accretion with equally likely stopping describes star formation in the dense parts of clusters, where models of isolated collapsing cores may not apply. Each core accretes at a constant rate onto its protostar, while the surrounding clump gas accretes as a power of protostar mass. Short accretion flows resemble Shu accretion, and make low-mass stars. Long flows resemble reduced Bondi accretion and make massive stars. Accretion stops due to environmental processes of dynamical ejection, gravitational competition, and gas dispersal by stellar feedback, independent of initial core structure. The model matches the field star IMF from 0.01 to more than 10 solar masses. The core accretion rate and the mean accretion duration set the peak of the IMF, independent of the local Jeans mass. Massive protostars require the longest accretion durations, up to 0.5 Myr. The maximum protostar luminosity in a cluster indicates the mass and age of its oldest protostar. The distribution of protostar luminosi...

  9. Correspondence Analysis applied to psychological research

    OpenAIRE

    Laura Doey; Jessica Kurta

    2011-01-01

    Correspondence analysis is an exploratory data technique used to analyze categorical data (Benzecri, 1992). It is used in many areas such as marketing and ecology. Correspondence analysis has been used less often in psychological research, although it can be suitably applied. This article discusses the benefits of using correspondence analysis in psychological research and provides a tutorial on how to perform correspondence analysis using the Statistical Package for the Social Sciences (SPSS).

  10. Correspondence Analysis applied to psychological research

    Directory of Open Access Journals (Sweden)

    Laura Doey

    2011-04-01

    Full Text Available Correspondence analysis is an exploratory data technique used to analyze categorical data (Benzecri, 1992. It is used in many areas such as marketing and ecology. Correspondence analysis has been used less often in psychological research, although it can be suitably applied. This article discusses the benefits of using correspondence analysis in psychological research and provides a tutorial on how to perform correspondence analysis using the Statistical Package for the Social Sciences (SPSS.

  11. MUSIC - Multifunctional stereo imaging camera system for wide angle and high resolution stereo and color observations on the Mars-94 mission

    Science.gov (United States)

    Oertel, D.; Jahn, H.; Sandau, R.; Walter, I.; Driescher, H.

    1990-10-01

    Objectives of the multifunctional stereo imaging camera (MUSIC) system to be deployed on the Soviet Mars-94 mission are outlined. A high-resolution stereo camera (HRSC) and wide-angle opto-electronic stereo scanner (WAOSS) are combined in terms of hardware, software, technology aspects, and solutions. Both HRSC and WAOSS are push-button instruments containing a single optical system and focal plates with several parallel CCD line sensors. Emphasis is placed on the MUSIC system's stereo capability, its design, mass memory, and data compression. A 1-Gbit memory is divided into two parts: 80 percent for HRSC and 20 percent for WAOSS, while the selected on-line compression strategy is based on macropixel coding and real-time transform coding.

  12. Research and Implementation of 3D Stereo Visual System for Flight Simulation

    Institute of Scientific and Technical Information of China (English)

    黄安祥; 于恒进; 陈宗基; 李明

    2002-01-01

    In military aircrafl fiight simulation, visual cues require depth sense,stereo sense and large field of view. To satisfy these requirements, we set up a space stereo visual system for flight simulation. This paper discusses the design issues of this visual system, including design principles, system implementations,as well as practical solutions to some key problems.

  13. Real 3D increases perceived depth over anaglyphs but does not cancel stereo-anomaly

    NARCIS (Netherlands)

    Kooi, F.L.; Dekker, D.; Ee, R. van; Brouwer, A.-M.

    2010-01-01

    Background: About 30% of the population has difficulties detecting the sign and the magnitude of binocular disparity in the absence of eye movements, a phenomenon called stereo-anomaly. The stereo-anomaly tests so far are based on disparity only (e.g. red-green stereograms), which means that other

  14. Thermophysical properties of warm dense hydrogen

    CERN Document Server

    Holst, Bastian; Desjarlais, Michael P

    2007-01-01

    We study the thermophysical properties of warm dense hydrogen using quantum molecular dynamics simulations. New results are presented for the pair distribution functions, the equation of state, the Hugoniot curve, and the reflectivity. We compare with available experimental data and predictions of the chemical picture. Especially, we discuss the nonmetal-to-metal transition which occurs at about 40 GPa in the dense fluid.

  15. Heavy meson production in hot dense matter

    NARCIS (Netherlands)

    Tolos, Laura; Gamermann, Daniel; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Nieves, JM; Oset, E; Vacas, MJV

    2010-01-01

    The properties of charmed mesons in dense matter are studied using a unitary coupled-channel approach in the nuclear medium which takes into account Pauli-blocking effects and meson self-energies in a self-consistent manner. We obtain the open-charm meson spectral functions in this dense nuclear env

  16. Finding dense locations in indoor tracking data

    DEFF Research Database (Denmark)

    Ahmed, Tanvir; Pedersen, Torben Bach; Lu, Hua

    2014-01-01

    Finding the dense locations in large indoor spaces is very useful for getting overloaded locations, security, crowd management, indoor navigation, and guidance. Indoor tracking data can be very large and are not readily available for finding dense locations. This paper presents a graph-based mode...

  17. Preparation for Moving a Rock on Mars, Stereo View

    Science.gov (United States)

    2008-01-01

    The robotic arm on NASA's Phoenix Mars Lander enlarged a trench beside a rock called 'Headless' during the mission's 115th Martian day (Sept. 20, 2008) in preparation for sliding the rock into the trench. The lander's Surface Stereo Imager took this image later that afternoon, showing the enlarged trench and the rock. The robotic arm successfully moved the rock two days later. The Phoenix science team sought to move the rock in order to study the soil and the depth to subsurface ice underneath where the rock had been. Headless is about the size and shape of a VHS videotape. The trench, called 'Neverland,' was excavated to about 3 centimeters (1.2 inches) deep near the rock. The ground surface between the rock and the lip of the trench slopes downward about 3 degrees toward the trench. The left-eye and right-eye images combined into this stereo view were taken at about 4:35 p.m., local solar time on Mars. The scene appears three-dimensional when seen through blue-red glasses. The view is to the north northeast of the lander. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

  18. A parallel stereo reconstruction algorithm with applications in entomology (APSRA)

    Science.gov (United States)

    Bhasin, Rajesh; Jang, Won Jun; Hart, John C.

    2012-03-01

    We propose a fast parallel algorithm for the reconstruction of 3-Dimensional point clouds of insects from binocular stereo image pairs using a hierarchical approach for disparity estimation. Entomologists study various features of insects to classify them, build their distribution maps, and discover genetic links between specimens among various other essential tasks. This information is important to the pesticide and the pharmaceutical industries among others. When considering the large collections of insects entomologists analyze, it becomes difficult to physically handle the entire collection and share the data with researchers across the world. With the method presented in our work, Entomologists can create an image database for their collections and use the 3D models for studying the shape and structure of the insects thus making it easier to maintain and share. Initial feedback shows that the reconstructed 3D models preserve the shape and size of the specimen. We further optimize our results to incorporate multiview stereo which produces better overall structure of the insects. Our main contribution is applying stereoscopic vision techniques to entomology to solve the problems faced by entomologists.

  19. Feature Augmentation for Learning Confidence Measure in Stereo Matching.

    Science.gov (United States)

    Kim, Sunok; Min, Dongbo; Kim, Seungryong; Sohn, Kwanghoon

    2017-09-08

    Confidence estimation is essential for refining stereo matching results through a post-processing step. This problem has recently been studied using a learning-based approach, which demonstrates a substantial improvement on conventional simple non-learning based methods. However, the formulation of learning-based methods that individually estimates the confidence of each pixel disregards spatial coherency that might exist in the confidence map, thus providing a limited performance under challenging conditions. Our key observation is that the confidence features and resulting confidence maps are smoothly varying in the spatial domain, and highly correlated within the local regions of an image. We present a new approach that imposes spatial consistency on the confidence estimation. Specifically, a set of robust confidence features is extracted from each superpixel decomposed using the Gaussian mixture model (GMM), and then these features are concatenated with pixel-level confidence features. The features are then enhanced through adaptive filtering in the feature domain. In addition, the resulting confidence map, estimated using the confidence features with a random regression forest, is further improved through K-nearest neighbor (K-NN) based aggregation scheme on both pixel-and superpixel-level. To validate the proposed confidence estimation scheme, we employ cost modulation or ground control points (GCPs) based optimization in stereo matching. Experimental results demonstrate that the proposed method outperforms state-of-the-art approaches on various benchmarks including challenging outdoor scenes.

  20. Cost aggregation and occlusion handling with WLS in stereo matching.

    Science.gov (United States)

    Min, Dongbo; Sohn, Kwanghoon

    2008-08-01

    This paper presents a novel method for cost aggregation and occlusion handling for stereo matching. In order to estimate optimal cost, given a per-pixel difference image as observed data, we define an energy function and solve the minimization problem by solving the iterative equation with the numerical method. We improve performance and increase the convergence rate by using several acceleration techniques such as the Gauss-Seidel method, the multiscale approach, and adaptive interpolation. The proposed method is computationally efficient since it does not use color segmentation or any global optimization techniques. For occlusion handling, which has not been performed effectively by any conventional cost aggregation approaches, we combine the occlusion problem with the proposed minimization scheme. Asymmetric information is used so that few additional computational loads are necessary. Experimental results show that performance is comparable to that of many state-of-the-art methods. The proposed method is in fact the most successful among all cost aggregation methods based on standard stereo test beds.

  1. A hybrid multiview stereo algorithm for modeling urban scenes.

    Science.gov (United States)

    Lafarge, Florent; Keriven, Renaud; Brédif, Mathieu; Vu, Hoang-Hiep

    2013-01-01

    We present an original multiview stereo reconstruction algorithm which allows the 3D-modeling of urban scenes as a combination of meshes and geometric primitives. The method provides a compact model while preserving details: Irregular elements such as statues and ornaments are described by meshes, whereas regular structures such as columns and walls are described by primitives (planes, spheres, cylinders, cones, and tori). We adopt a two-step strategy consisting first in segmenting the initial meshbased surface using a multilabel Markov Random Field-based model and second in sampling primitive and mesh components simultaneously on the obtained partition by a Jump-Diffusion process. The quality of a reconstruction is measured by a multi-object energy model which takes into account both photo-consistency and semantic considerations (i.e., geometry and shape layout). The segmentation and sampling steps are embedded into an iterative refinement procedure which provides an increasingly accurate hybrid representation. Experimental results on complex urban structures and large scenes are presented and compared to state-of-the-art multiview stereo meshing algorithms.

  2. Signatures of Interchange Reconnection: STEREO, ACE and Hinode Observations Combined

    CERN Document Server

    Baker, D; Van Driel-Gesztelyi, L; Demoulin, P; Harra, L K; Lavraud, B; Davies, J A; Optiz, A; Luhmann, J G; Sauvaud, J A; Galvin, A B

    2009-01-01

    Combining STEREO, ACE and Hinode observations has presented an opportunity to follow a filament eruption and coronal mass ejection (CME) on the 17th of October 2007 from an active region (AR) inside a coronal hole (CH) into the heliosphere. This particular combination of `open' and closed magnetic topologies provides an ideal scenario for interchange reconnection to take place. With Hinode and STEREO data we were able to identify the emergence time and type of structure seen in the in-situ data four days later. On the 21st, ACE observed in-situ the passage of an ICME with `open' magnetic topology. The magnetic field configuration of the source, a mature AR located inside an equatorial CH, has important implications for the solar and interplanetary signatures of the eruption. We interpret the formation of an `anemone' structure of the erupting AR and the passage in-situ of the ICME being disconnected at one leg, as manifested by uni-directional suprathermal electron flux in the ICME, to be a direct result of i...

  3. The High Energy Telescopes for the STEREO Mission

    Science.gov (United States)

    von Rosenvinge, T.T.; Cummings, A.C.; Leske, R.A.; Mewaldt, R.A.; Reames, D.V.; Stone, E.C.; Wiedenbeck, M.E.

    We describe the High Energy Telescopes (HETs), which are part of the IMPACT investigation for the STEREO mission (Principal Investigator: Janet Luhmann, University of California at Berkeley). The two STEREO spacecraft were launched from Cape Canaveral, FL on October 25, 2006. High energy electrons (~ 0.7 -6 MeV) and nuclei from hydrogen to iron (~ 13 - 200 MeV/nucleon) are detected by the HETs, one on each spacecraft. Observations from one pass through the Earth’s magnetosphere and from four X-class solar events in December, 2006 are presented to illustrate the capabilities of the HETs. The HET observations are also compared with observations from other spacecraft. The event of December 13th was the first Ground Level Event in almost two years. We will compare the elemental composition of this event with that of the previous Ground Level Event on January 20, 2005. This work was supported by NASA (at Caltech and JPL under contract NAS5-00133 and grant NAG5-12929).

  4. A 3D terrain reconstruction method of stereo vision based quadruped robot navigation system

    Science.gov (United States)

    Ge, Zhuo; Zhu, Ying; Liang, Guanhao

    2017-01-01

    To provide 3D environment information for the quadruped robot autonomous navigation system during walking through rough terrain, based on the stereo vision, a novel 3D terrain reconstruction method is presented. In order to solve the problem that images collected by stereo sensors have large regions with similar grayscale and the problem that image matching is poor at real-time performance, watershed algorithm and fuzzy c-means clustering algorithm are combined for contour extraction. Aiming at the problem of error matching, duel constraint with region matching and pixel matching is established for matching optimization. Using the stereo matching edge pixel pairs, the 3D coordinate algorithm is estimated according to the binocular stereo vision imaging model. Experimental results show that the proposed method can yield high stereo matching ratio and reconstruct 3D scene quickly and efficiently.

  5. Fast repurposing of high-resolution stereo video content for mobile use

    Science.gov (United States)

    Karaoglu, Ali; Lee, Bong Ho; Boev, Atanas; Cheong, Won-Sik; Gotchev, Atanas

    2012-06-01

    3D video content is captured and created mainly in high resolution targeting big cinema or home TV screens. For 3D mobile devices, equipped with small-size auto-stereoscopic displays, such content has to be properly repurposed, preferably in real-time. The repurposing requires not only spatial resizing but also properly maintaining the output stereo disparity, as it should deliver realistic, pleasant and harmless 3D perception. In this paper, we propose an approach to adapt the disparity range of the source video to the comfort disparity zone of the target display. To achieve this, we adapt the scale and the aspect ratio of the source video. We aim at maximizing the disparity range of the retargeted content within the comfort zone, and minimizing the letterboxing of the cropped content. The proposed algorithm consists of five stages. First, we analyse the display profile, which characterises what 3D content can be comfortably observed in the target display. Then, we perform fast disparity analysis of the input stereoscopic content. Instead of returning the dense disparity map, it returns an estimate of the disparity statistics (min, max, meanand variance) per frame. Additionally, we detect scene cuts, where sharp transitions in disparities occur. Based on the estimated input, and desired output disparity ranges, we derive the optimal cropping parameters and scale of the cropping window, which would yield the targeted disparity range and minimize the area of cropped and letterboxed content. Once the rescaling and cropping parameters are known, we perform resampling procedure using spline-based and perceptually optimized resampling (anti-aliasing) kernels, which have also a very efficient computational structure. Perceptual optimization is achieved through adjusting the cut-off frequency of the anti-aliasing filter with the throughput of the target display.

  6. The High Resolution Stereo Camera (HRSC) of Mars Express and its approach to science analysis and mapping for Mars and its satellites

    Science.gov (United States)

    Gwinner, K.; Jaumann, R.; Hauber, E.; Hoffmann, H.; Heipke, C.; Oberst, J.; Neukum, G.; Ansan, V.; Bostelmann, J.; Dumke, A.; Elgner, S.; Erkeling, G.; Fueten, F.; Hiesinger, H.; Hoekzema, N. M.; Kersten, E.; Loizeau, D.; Matz, K.-D.; McGuire, P. C.; Mertens, V.; Michael, G.; Pasewaldt, A.; Pinet, P.; Preusker, F.; Reiss, D.; Roatsch, T.; Schmidt, R.; Scholten, F.; Spiegel, M.; Stesky, R.; Tirsch, D.; van Gasselt, S.; Walter, S.; Wählisch, M.; Willner, K.

    2016-07-01

    The High Resolution Stereo Camera (HRSC) of ESA's Mars Express is designed to map and investigate the topography of Mars. The camera, in particular its Super Resolution Channel (SRC), also obtains images of Phobos and Deimos on a regular basis. As HRSC is a push broom scanning instrument with nine CCD line detectors mounted in parallel, its unique feature is the ability to obtain along-track stereo images and four colors during a single orbital pass. The sub-pixel accuracy of 3D points derived from stereo analysis allows producing DTMs with grid size of up to 50 m and height accuracy on the order of one image ground pixel and better, as well as corresponding orthoimages. Such data products have been produced systematically for approximately 40% of the surface of Mars so far, while global shape models and a near-global orthoimage mosaic could be produced for Phobos. HRSC is also unique because it bridges between laser altimetry and topography data derived from other stereo imaging instruments, and provides geodetic reference data and geological context to a variety of non-stereo datasets. This paper, in addition to an overview of the status and evolution of the experiment, provides a review of relevant methods applied for 3D reconstruction and mapping, and respective achievements. We will also review the methodology of specific approaches to science analysis based on joint analysis of DTM and orthoimage information, or benefitting from high accuracy of co-registration between multiple datasets, such as studies using multi-temporal or multi-angular observations, from the fields of geomorphology, structural geology, compositional mapping, and atmospheric science. Related exemplary results from analysis of HRSC data will be discussed. After 10 years of operation, HRSC covered about 70% of the surface by panchromatic images at 10-20 m/pixel, and about 97% at better than 100 m/pixel. As the areas with contiguous coverage by stereo data are increasingly abundant, we also

  7. Modeling the jet quenching in hot and dense QCD matter

    CERN Document Server

    Lokhtin, I P; Petrushanko, S V; Snigirev, A M; Arsene, I; Tywoniuk, K

    2009-01-01

    One of the important perturbative ("hard") probes of hot and dense QCD matter is the medium-induced energy loss of energetic partons, so called "jet quenching", which is predicted to be very different in cold nuclear matter and in QGP, and leads to a number of phenomena which are already seen in the RHIC data on the qualitative level. The inclusion of jet quenching and other important collective effects, such as radial and elliptic flows, in the existing Monte-Carlo models of relativistic heavy ion collisions is discussed. Some issues on the corresponding physical observables at RHIC and LHC energies obtained with HYDJET++ model are presented.

  8. Electromagnetic Properties of a Hot and Dense Medium

    CERN Document Server

    Masood, Samina

    2016-01-01

    We study the properties of an electromagnetically interacting medium in the presence of high concentration of electrons at extremely high temperatures and chemical potentials. We show that the electromagnetic properties of a medium such as the electric permittivity, magnetic permeability, magnetic moments and the propagation speed of electromagnetic waves as well as the corresponding particle processes depend on temperature and density of the medium. Electromagnetic properties of neutrinos are significantly modified due to their interactions with electrons when they propagate through such a medium of hot and dense electrons.

  9. Gas dynamics in Massive Dense Cores in Cygnus-X

    CERN Document Server

    Csengeri, T; Schneider, N; Motte, F; Dib, S

    2010-01-01

    We study the kinematic properties of dense gas surrounding massive protostars recognized by Bontemps et a. (2010) in a sample of five Massive Dense Cores in Cygnus-X. We investigate whether turbulent support plays a major role in stabilizing the core against fragmentation into Jeans-mass objects or alternatively, the observed kinematics could indicate a high level of dynamics. We present IRAM 30m single-dish (HCO+ and H13CO+) and IRAM PdBI high angular-resolution observations of dense gas tracers (H13CO+ and H13CN) to reveal the kinematics of molecular gas at scales from 0.03 to 0.1 pc. Radiative transfer modeling shows that H13CO+ is depleted within the envelopes of massive protostars and traces the bulk of material surrounding the protostars rather than their inner envelopes. H13CN shows a better correspondence with the peak of the continuum emission, possibly due to abundance anomalies and specific chemistry in the close vicinity of massive protostars. Analyzing the line-widths we show that the observed li...

  10. Dense Cloud Formation and Star Formation in a Barred Galaxy

    CERN Document Server

    Nimori, M; Sorai, K; Watanabe, Y; Hirota, A; Namekata, D

    2012-01-01

    We investigate the properties of massive, dense clouds formed in a barred galaxy and their possible relation to star formation, performing a two-dimensional hydrodynamical simulation with the gravitational potential obtained from the 2Mass data from the barred spiral galaxy, M83. Since the environment for cloud formation and evolution in the bar region is expected to be different from that in the spiral arm region, barred galaxies are a good target to study the environmental effects on cloud formation and the subsequent star formation. Our simulation uses for an initial 80 Myr an isothermal flow of non-self gravitating gas in the barred potential, then including radiative cooling, heating and self-gravitation of the gas for the next 40 Myr, during which dense clumps are formed. We identify many cold, dense gas clumps for which the mass is more than $10^4M_{\\odot}$ (a value corresponding to the molecular clouds) and study the physical properties of these clumps. The relation of the velocity dispersion of the i...

  11. Cross-Modality Hashing with Partial Correspondence

    OpenAIRE

    Gu, Yun; Xue, Haoyang; Yang,Jie

    2015-01-01

    Learning a hashing function for cross-media search is very desirable due to its low storage cost and fast query speed. However, the data crawled from Internet cannot always guarantee good correspondence among different modalities which affects the learning for hashing function. In this paper, we focus on cross-modal hashing with partially corresponded data. The data without full correspondence are made in use to enhance the hashing performance. The experiments on Wiki and NUS-WIDE datasets de...

  12. Picking up Clues from the Discard Pile (Stereo)

    Science.gov (United States)

    2008-01-01

    As NASA's Phoenix Mars Lander excavates trenches, it also builds piles with most of the material scooped from the holes. The piles, like this one called 'Caterpillar,' provide researchers some information about the soil. On Aug. 24, 2008, during the late afternoon of the 88th Martian day after landing, Phoenix's Surface Stereo Imager took separate exposures through its left eye and right eye that have been combined into this stereo view. The image appears three dimensional when seen through red-blue glasses. This conical pile of soil is about 10 centimeters (4 inches) tall. The sources of material that the robotic arm has dropped onto the Caterpillar pile have included the 'Dodo' and ''Upper Cupboard' trenches and, more recently, the deeper 'Stone Soup' trench. Observations of the pile provide information, such as the slope of the cone and the textures of the soil, that helps scientists understand properties of material excavated from the trenches. For the Stone Soup trench in particular, which is about 18 centimeters (7 inches) deep, the bottom of the trench is in shadow and more difficult to observe than other trenches that Phoenix has dug. The Phoenix team obtained spectral clues about the composition of material from the bottom of Stone Soup by photographing Caterpillar through 15 different filters of the Surface Stereo Imager when the pile was covered in freshly excavated material from the trench. The spectral observation did not produce any sign of water-ice, just typical soil for the site. However, the bigger clumps do show a platy texture that could be consistent with elevated concentration of salts in the soil from deep in Stone Soup. The team chose that location as the source for a soil sample to be analyzed in the lander's wet chemistry laboratory, which can identify soluble salts in the soil. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory

  13. Department of the Navy Correspondence Manual

    Science.gov (United States)

    2010-03-01

    Correspondence 2-6 9 Outgoing Correspondence Controls 2-7 10 Limit Use of Social Security Numbers (SSN) 2-7 11 Identifying Navy and Marine Corps Personnel 2-7 12...the correspondence was originally sent to by phone or via e-mail. 10. Limit Use of Social Security Numbers (SSN) a. Corresponding Within the...Stravenue STRA Cove CV Loaf LF Stream STRM Creek CRK Locks LCKS Street ST Crescent CRES Lodge LDG Summit SMT Crossing XING Loop LOOP Terrace TER Dale DL

  14. Correspondence analysis theory, practice and new strategies

    CERN Document Server

    Beh, Eric J

    2014-01-01

    A comprehensive overview of the internationalisation of correspondence analysis Correspondence Analysis: Theory, Practice and New Strategies examines the key issues of correspondence analysis, and discusses the new advances that have been made over the last 20 years. The main focus of this book is to provide a comprehensive discussion of some of the key technical and practical aspects of correspondence analysis, and to demonstrate how they may be put to use.  Particular attention is given to the history and mathematical links of the developments made. These links include not just those majo

  15. Disparity map generation from illumination variant stereo images using efficient hierarchical dynamic programming.

    Science.gov (United States)

    Borisagar, Viral H; Zaveri, Mukesh A

    2014-01-01

    A novel hierarchical stereo matching algorithm is presented which gives disparity map as output from illumination variant stereo pair. Illumination difference between two stereo images can lead to undesirable output. Stereo image pair often experience illumination variations due to many factors like real and practical situation, spatially and temporally separated camera positions, environmental illumination fluctuation, and the change in the strength or position of the light sources. Window matching and dynamic programming techniques are employed for disparity map estimation. Good quality disparity map is obtained with the optimized path. Homomorphic filtering is used as a preprocessing step to lessen illumination variation between the stereo images. Anisotropic diffusion is used to refine disparity map to give high quality disparity map as a final output. The robust performance of the proposed approach is suitable for real life circumstances where there will be always illumination variation between the images. The matching is carried out in a sequence of images representing the same scene, however in different resolutions. The hierarchical approach adopted decreases the computation time of the stereo matching problem. This algorithm can be helpful in applications like robot navigation, extraction of information from aerial surveys, 3D scene reconstruction, and military and security applications. Similarity measure SAD is often sensitive to illumination variation. It produces unacceptable disparity map results for illumination variant left and right images. Experimental results show that our proposed algorithm produces quality disparity maps for both wide range of illumination variant and invariant stereo image pair.

  16. Disparity Map Generation from Illumination Variant Stereo Images Using Efficient Hierarchical Dynamic Programming

    Directory of Open Access Journals (Sweden)

    Viral H. Borisagar

    2014-01-01

    Full Text Available A novel hierarchical stereo matching algorithm is presented which gives disparity map as output from illumination variant stereo pair. Illumination difference between two stereo images can lead to undesirable output. Stereo image pair often experience illumination variations due to many factors like real and practical situation, spatially and temporally separated camera positions, environmental illumination fluctuation, and the change in the strength or position of the light sources. Window matching and dynamic programming techniques are employed for disparity map estimation. Good quality disparity map is obtained with the optimized path. Homomorphic filtering is used as a preprocessing step to lessen illumination variation between the stereo images. Anisotropic diffusion is used to refine disparity map to give high quality disparity map as a final output. The robust performance of the proposed approach is suitable for real life circumstances where there will be always illumination variation between the images. The matching is carried out in a sequence of images representing the same scene, however in different resolutions. The hierarchical approach adopted decreases the computation time of the stereo matching problem. This algorithm can be helpful in applications like robot navigation, extraction of information from aerial surveys, 3D scene reconstruction, and military and security applications. Similarity measure SAD is often sensitive to illumination variation. It produces unacceptable disparity map results for illumination variant left and right images. Experimental results show that our proposed algorithm produces quality disparity maps for both wide range of illumination variant and invariant stereo image pair.

  17. a Robust Method for Stereo Visual Odometry Based on Multiple Euclidean Distance Constraint and Ransac Algorithm

    Science.gov (United States)

    Zhou, Q.; Tong, X.; Liu, S.; Lu, X.; Liu, S.; Chen, P.; Jin, Y.; Xie, H.

    2017-07-01

    Visual Odometry (VO) is a critical component for planetary robot navigation and safety. It estimates the ego-motion using stereo images frame by frame. Feature points extraction and matching is one of the key steps for robotic motion estimation which largely influences the precision and robustness. In this work, we choose the Oriented FAST and Rotated BRIEF (ORB) features by considering both accuracy and speed issues. For more robustness in challenging environment e.g., rough terrain or planetary surface, this paper presents a robust outliers elimination method based on Euclidean Distance Constraint (EDC) and Random Sample Consensus (RANSAC) algorithm. In the matching process, a set of ORB feature points are extracted from the current left and right synchronous images and the Brute Force (BF) matcher is used to find the correspondences between the two images for the Space Intersection. Then the EDC and RANSAC algorithms are carried out to eliminate mismatches whose distances are beyond a predefined threshold. Similarly, when the left image of the next time matches the feature points with the current left images, the EDC and RANSAC are iteratively performed. After the above mentioned, there are exceptional remaining mismatched points in some cases, for which the third time RANSAC is applied to eliminate the effects of those outliers in the estimation of the ego-motion parameters (Interior Orientation and Exterior Orientation). The proposed approach has been tested on a real-world vehicle dataset and the result benefits from its high robustness.

  18. Finger tracking for hand-held device interface using profile-matching stereo vision

    Science.gov (United States)

    Chang, Yung-Ping; Lee, Dah-Jye; Moore, Jason; Desai, Alok; Tippetts, Beau

    2013-01-01

    Hundreds of millions of people use hand-held devices frequently and control them by touching the screen with their fingers. If this method of operation is being used by people who are driving, the probability of deaths and accidents occurring substantially increases. With a non-contact control interface, people do not need to touch the screen. As a result, people will not need to pay as much attention to their phones and thus drive more safely than they would otherwise. This interface can be achieved with real-time stereovision. A novel Intensity Profile Shape-Matching Algorithm is able to obtain 3-D information from a pair of stereo images in real time. While this algorithm does have a trade-off between accuracy and processing speed, the result of this algorithm proves the accuracy is sufficient for the practical use of recognizing human poses and finger movement tracking. By choosing an interval of disparity, an object at a certain distance range can be segmented. In other words, we detect the object by its distance to the cameras. The advantage of this profile shape-matching algorithm is that detection of correspondences relies on the shape of profile and not on intensity values, which are subjected to lighting variations. Based on the resulting 3-D information, the movement of fingers in space from a specific distance can be determined. Finger location and movement can then be analyzed for non-contact control of hand-held devices.

  19. Project Report: Reducing Color Rivalry in Imagery for Conjugated Multiple Bandpass Filter Based Stereo Endoscopy

    Science.gov (United States)

    Ream, Allen

    2011-01-01

    A pair of conjugated multiple bandpass filters (CMBF) can be used to create spatially separated pupils in a traditional lens and imaging sensor system allowing for the passive capture of stereo video. This method is especially useful for surgical endoscopy where smaller cameras are needed to provide ample room for manipulating tools while also granting improved visualizations of scene depth. The significant issue in this process is that, due to the complimentary nature of the filters, the colors seen through each filter do not match each other, and also differ from colors as seen under a white illumination source. A color correction model was implemented that included optimized filter selection, such that the degree of necessary post-processing correction was minimized, and a chromatic adaptation transformation that attempted to fix the imaged colors tristimulus indices based on the principle of color constancy. Due to fabrication constraints, only dual bandpass filters were feasible. The theoretical average color error after correction between these filters was still above the fusion limit meaning that rivalry conditions are possible during viewing. This error can be minimized further by designing the filters for a subset of colors corresponding to specific working environments.

  20. Critical factors in SEM 3D stereo microscopy

    DEFF Research Database (Denmark)

    Marinello, F.; Bariano, P.; Savio, E.;

    2008-01-01

    This work addresses dimensional measurements performed with the scanning electron microscope (SEM) using 3D reconstruction of surface topography through stereo-photogrammetry. The paper presents both theoretical and experimental investigations, on the effects of instrumental variables...... factors are recognized: the first one is related to the measurement operation and the instrument set-up; the second concerns the quality of scanned images and represents the major criticality in the application of SEMs for 3D characterizations....... and measurement parameters on reconstruction accuracy. Investigations were performed on a novel sample, specifically developed and implemented for the tests. The description is based on the model function introduced by Piazzesi and adapted for eucentrically tilted stereopairs. Two main classes of influencing...

  1. Bootstrapping the Coronal Magnetic Field with STEREO/EUVI

    Science.gov (United States)

    Aschwanden, Markus; Sandman, Anne

    2010-05-01

    The 3D coronal magnetic field obtained from stereoscopically triangulated loops has been compared with standard photospheric magnetogram extrapolations. We found a large misalignment of 20-40 deg, depending on the complexity of an AR (Sandman et al. 2009; DeRosa et al. 2009). These studies prove that the magnetic field in the photosphere is not force-free and fundamentally cannot reproduce the coronal magnetic field. Bootstrapping with coronal loop 3D geometries are required to improve modeling of the coronal field. Such coronal field bootstrapping methods are currently developed using stereoscopically triangulated loops from STEREO/EUVI and preliminary results show already a significantly reduced misalignment of 10-20 deg.

  2. Stereo optical tracker for standoff monitoring of position and orientation

    Science.gov (United States)

    Sherman, W. D.; Houk, T. L.; Saint Clair, J. M.; Sjoholm, P. F.; Voth, M. D.

    2009-01-01

    A Precision Optical Measurement System (POMS) has been designed, constructed and tested for tracking the position (x, y, z) and orientation (roll, pitch, yaw) of models in Boeing's 9-77 Compact Radar Range. A stereo triangulation technique is implemented using two remote sensor units separated by a known baseline. Each unit measures pointing angles (azimuth and elevation) to optical targets on a model. Four different reference systems are used for calibration and alignment of the system's components and two platforms. Pointing angle data and calibration corrections are processed at high rates to give near real-time feedback to the mechanical positioning system of the model. The positional accuracy of the system is +/- .010 inches at a distance of 85 feet while using low RCS reflective tape targets. The precision measurement capabilities and applications of the system are discussed.

  3. StereoPasting: interactive composition in stereoscopic images.

    Science.gov (United States)

    Tong, Ruo-Feng; Zhang, Yun; Cheng, Ke-Li

    2013-08-01

    We propose "StereoPasting," an efficient method for depth-consistent stereoscopic composition, in which a source 2D image is interactively blended into a target stereoscopic image. As we paint "disparity" on a 2D image, the disparity map of the selected region is gradually produced by edge-aware diffusion, and then blended with that of the target stereoscopic image. By considering constraints of the expected disparities and perspective scaling, the 2D object is warped to generate an image pair, which is then blended into the target image pair to get the composition result. The warping is formulated as an energy minimization, which could be solved in real time. We also present an interactive composition system, in which users can edit the disparity maps of 2D images by strokes, while viewing the composition results instantly. Experiments show that our method is intuitive and efficient for interactive stereoscopic composition. A lot of applications demonstrate the versatility of our method.

  4. Two Holes from Using Rasp in 'Snow White' (Stereo)

    Science.gov (United States)

    2008-01-01

    This view from the Surface Stereo Imager on NASA's Phoenix Mars Lander shows a portion of the trench informally named 'Snow White,' with two holes near the top of the image that were produced by the first test use of Phoenix's rasp to collect a sample of icy soil. The test was conducted on July 15, 2008, during the 50th Martian day, or sol, since Phoenix landed, and the image was taken later the same day. The two holes are about one centimeter (0.4 inch) apart. The image appears three-dimensional when viewed through blue-red glasses. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  5. Visual tracking in stereo. [by computer vision system

    Science.gov (United States)

    Saund, E.

    1981-01-01

    A method is described for visual object tracking by a computer vision system using TV cameras and special low-level image processing hardware. The tracker maintains an internal model of the location, orientation, and velocity of the object in three-dimensional space. This model is used to predict where features of the object will lie on the two-dimensional images produced by stereo TV cameras. The differences in the locations of features in the two-dimensional images as predicted by the internal model and as actually seen create an error signal in the two-dimensional representation. This is multiplied by a generalized inverse Jacobian matrix to deduce the error in the internal model. The procedure repeats to update the internal model of the object's location, orientation and velocity continuously.

  6. Characteristics of EUV coronal jets observed with STEREO/SECCHI

    CERN Document Server

    Nistico, G; Patsourakos, S; Zimbardo, G

    2009-01-01

    In this paper we present the first comprehensive statistical study of EUV coronal jets observed with the SECCHI imaging suites of the two STEREO spacecraft. A catalogue of 79 polar jets is presented, identified from simultaneous EUV and white-light coronagraph observations, taken during the time period March 2007 to April 2008. The appearances of the coronal jets were always correlated with underlying small-scale chromospheric bright points. A basic characterisation of the morphology and identification of the presence of helical structure were established with respect to recently proposed models for their origin and temporal evolution. A classification of the events with respect to previous jet studies shows that amongst the 79 events there were 37 Eiffel tower-type jet events commonly interpreted as a small-scale (about 35 arcsec) magnetic bipole reconnecting with the ambient unipolar open coronal magnetic fields at its looptops, and 12 lambda-type jet events commonly interpreted as reconnection with the amb...

  7. A wavelet-based quadtree driven stereo image coding

    Science.gov (United States)

    Bensalma, Rafik; Larabi, Mohamed-Chaker

    2009-02-01

    In this work, a new stereo image coding technique is proposed. The new approach integrates the coding of the residual image with the disparity map. The latter computed in the wavelet transform domain. The motivation behind using this transform is that it imitates some properties of the human visual system (HVS), particularly, the decomposition in the perspective canals. Therefore, using the wavelet transform allows for better perceptual image quality preservation. In order to estimate the disparity map, we used a quadtree segmentation in each wavelet frequency band. This segmentation has the advantage of minimizing the entropy. Dyadic squares in the subbands of target image that they are not matched with other in the reference image constitutes the residuals are coded by using an arithmetic codec. The obtained results are evaluated by using the SSIM and PSNR criteria.

  8. Stereo particle image velocimetry applied to a vortex pipe flow

    Science.gov (United States)

    Zhang, Zherui; Hugo, Ronald J.

    2006-03-01

    Stereo particle image velocimetry (PIV) has been employed to study a vortex generated via tangential injection of water in a 2.25 inch (57 mm) diameter pipe for Reynolds numbers ranging from 1,118 to 63,367. Methods of decreasing pipe-induced optical distortion and the PIV calibration technique are addressed. The mean velocity field analyses have shown spatial similarity and revealed four distinct flow regions starting from the central axis of rotation to the pipe wall in the vortex flows. Turbulence statistical data and vortex core location data suggest that velocity fluctuations are due to the axis of the in-line vortex distorting in the shape of a spiral.

  9. Pedestrian Counting with Occlusion Handling Using Stereo Thermal Cameras

    Directory of Open Access Journals (Sweden)

    Miklas S. Kristoffersen

    2016-01-01

    Full Text Available The number of pedestrians walking the streets or gathered in public spaces is a valuable piece of information for shop owners, city governments, event organizers and many others. However, automatic counting that takes place day and night is challenging due to changing lighting conditions and the complexity of scenes with many people occluding one another. To address these challenges, this paper introduces the use of a stereo thermal camera setup for pedestrian counting. We investigate the reconstruction of 3D points in a pedestrian street with two thermal cameras and propose an algorithm for pedestrian counting based on clustering and tracking of the 3D point clouds. The method is tested on two five-minute video sequences captured at a public event with a moderate density of pedestrians and heavy occlusions. The counting performance is compared to the manually annotated ground truth and shows success rates of 95.4% and 99.1% for the two sequences.

  10. Blind detection for disparity-coherent stereo video watermarking

    Science.gov (United States)

    Burini, César; Baudry, Séverine; Doërr, Gwenaël.

    2014-02-01

    Stereo video content calls for new watermarking strategies, e.g. to achieve robustness against virtual view synthesis. Prior works focused either on inserting the watermark in an invariant domain or on guaranteeing that the watermarks introduced in the left and right views are coherent with the disparity of the scene. However, the first approach raises fidelity issues while the second requires side information at detection i.e. the detector is not blind. In this paper, we propose a new blind detection procedure for disparity-coherent watermarks. In a nutshell, the detector relies on cross-correlation to aggregate the scattered pieces of the embedded reference watermark pattern rather than warping the reference pattern according to the parameters of the current view prior to detection. Reported experimental results indicate that this revisited detector successfully manages to retrieve embedded watermarks even after lossy compression.

  11. An Effective Stereo Visualization System Implementation for Virtual Prototyping

    Directory of Open Access Journals (Sweden)

    R.S. Kamath

    2010-10-01

    Full Text Available Virtual Reality technology is becoming an increasingly popular in diverse areas from scientific data analysis to entertainment. An important feature of this technology is the Stereoscopic display of computer-generated images to produce three-dimensional visual effects. The visualization tool is an ASCII text file driven system to visually simulate the modeled operation in 3D virtual space. Stereovision improves the manufacturing process by analyzing the product before its actual manufacturing. The goal of the virtual prototyping environment is to decrease product development time and costs and also to increase quality by providing continuous computer support for the development cycle. This paper addresses implementation of 3D stereo visualization system which serves in virtual prototyping for productivity improvement in Manufacturing Processes.

  12. Rover's Wheel Churns Up Bright Martian Soil (Stereo)

    Science.gov (United States)

    2009-01-01

    NASA's Mars Exploration Rover Spirit acquired this mosaic on the mission's 1,202nd Martian day, or sol (May 21, 2007), while investigating the area east of the elevated plateau known as 'Home Plate' in the 'Columbia Hills.' The mosaic shows an area of disturbed soil, nicknamed 'Gertrude Weise' by scientists, made by Spirit's stuck right front wheel. The trench exposed a patch of nearly pure silica, with the composition of opal. It could have come from either a hot-spring environment or an environment called a fumarole, in which acidic, volcanic steam rises through cracks. Either way, its formation involved water, and on Earth, both of these types of settings teem with microbial life. Multiple images taken with Spirit's panoramic camera are combined here into a stereo view that appears three-dimensional when seen through red-blue glasses, with the red lens on the left.

  13. Visual tracking in stereo. [by computer vision system

    Science.gov (United States)

    Saund, E.

    1981-01-01

    A method is described for visual object tracking by a computer vision system using TV cameras and special low-level image processing hardware. The tracker maintains an internal model of the location, orientation, and velocity of the object in three-dimensional space. This model is used to predict where features of the object will lie on the two-dimensional images produced by stereo TV cameras. The differences in the locations of features in the two-dimensional images as predicted by the internal model and as actually seen create an error signal in the two-dimensional representation. This is multiplied by a generalized inverse Jacobian matrix to deduce the error in the internal model. The procedure repeats to update the internal model of the object's location, orientation and velocity continuously.

  14. 12 CFR 7.5007 - Correspondent services.

    Science.gov (United States)

    2010-01-01

    ... Electronic Activities § 7.5007 Correspondent services. It is part of the business of banking for a national... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Correspondent services. 7.5007 Section 7.5007... any service it may perform for itself. The following list provides examples of electronic activities...

  15. Improving Cartosat-1 DEM accuracy using synthetic stereo pair and triplet

    Science.gov (United States)

    Giribabu, D.; Srinivasa Rao, S.; Krishna Murthy, Y. V. N.

    2013-03-01

    Cartosat-1 is the first Indian Remote Sensing Satellite capable of providing along-track stereo images. Cartosat-1 provides forward stereo images with look angles +26° and -5° with respect to nadir for generating Digital Elevation Models (DEMs), Orthoimages and value added products for various applications. A pitch bias of -21° to the satellite resulted in giving reverse tilt mode stereo pair with look angles of +5° and -26° with respect to nadir. This paper compares DEMs generated using forward, reverse and other possible synthetic stereo pairs for two different types of topographies. Stereo triplet was used to generate DEM for Himalayan mountain topography to overcome the problem of occlusions. For flat to undulating topography it was shown that using Cartosat-1 synthetic stereo pair with look angles of -26° and +26° will produce improved version of DEM. Planimetric and height accuracy (Root Mean Square Error (RMSE)) of less than 2.5 m and 2.95 m respectively were obtained and qualitative analysis shows finer details in comparison with other DEMs. For rugged terrain and steep slopes of Himalayan mountain topography simple stereo pairs may not provide reliable accuracies in DEMs due to occlusions and shadows. Stereo triplet from Cartosat-1 was used to generate DEM for mountainous topography. This DEM shows better reconstruction of elevation model even at occluded region when compared with simple stereo pair based DEM. Planimetric and height accuracy (RMSE) of nearly 3 m were obtained and qualitative analysis shows reduction of outliers at occluded region.

  16. Application of Stereo PIV on a Supersonic Parachute Model

    Science.gov (United States)

    Wernet, Mark P.; Locke, Randy J.; Wroblewski, Adam; Sengupta, Anita

    2009-01-01

    The Mars Science Laboratory (MSL) is the next step in NASA's Mars Exploration Program, currently scheduled for 2011. The spacecraft's descent into the Martian atmosphere will be slowed from Mach 2 to subsonic speeds via a large parachute system with final landing under propulsive control. A Disk-Band-Gap (DBG) parachute will be used on MSL similar to the designs that have been used on previous missions, however; the DBG parachute used by MSL will be larger (21.5 m) than in any of the previous missions due to the weight of the payload and landing site requirements. The MSL parachute will also deploy at higher Mach number (M 2) than previous parachutes, which can lead to instabilities in canopy performance. Both the increased size of the DBG above previous demonstrated configurations and deployment at higher Mach numbers add uncertainty to the deployment, structural integrity and performance of the parachute. In order to verify the performance of the DBG on MSL, experimental testing, including acquisition of Stereo Particle Imaging Velocimetry (PIV) measurements were required for validating CFD predictions of the parachute performance. A rigid model of the DBG parachute was tested in the 10x10 foot wind tunnel at GRC. Prior to the MSL tests, a PIV system had never been used in the 10x10 wind tunnel. In this paper we discuss some of the technical challenges overcome in implementing a Stereo PIV system with a 750x400 mm field-of-view in the 10x10 wind tunnel facility and results from the MSL hardshell canopy tests.

  17. Miniature photometric stereo system for textile surface structure reconstruction

    Science.gov (United States)

    Gorpas, Dimitris; Kampouris, Christos; Malassiotis, Sotiris

    2013-04-01

    In this work a miniature photometric stereo system is presented, targeting the three-dimensional structural reconstruction of various fabric types. This is a supportive module to a robot system, attempting to solve the well known "laundry problem". The miniature device has been designed for mounting onto the robot gripper. It is composed of a low-cost off-the-shelf camera, operating in macro mode, and eight light emitting diodes. The synchronization between image acquisition and lighting direction is controlled by an Arduino Nano board and software triggering. The ambient light has been addressed by a cylindrical enclosure. The direction of illumination is recovered by locating the reflection or the brightest point on a mirror sphere, while a flatfielding process compensates for the non-uniform illumination. For the evaluation of this prototype, the classical photometric stereo methodology has been used. The preliminary results on a large number of textiles are very promising for the successful integration of the miniature module to the robot system. The required interaction with the robot is implemented through the estimation of the Brenner's focus measure. This metric successfully assesses the focus quality with reduced time requirements in comparison to other well accepted focus metrics. Besides the targeting application, the small size of the developed system makes it a very promising candidate for applications with space restrictions, like the quality control in industrial production lines or object recognition based on structural information and in applications where easiness in operation and light-weight are required, like those in the Biomedical field, and especially in dermatology.

  18. Single detector stereo-SCIDAR for Mount Stromlo

    Science.gov (United States)

    Grosse, Doris; Bennet, Francis; Korkiakoski, Visa; Rigaut, Francois; Thorn, Elliott

    2016-07-01

    Satellite tracking and imaging is conducted by the ANU Research School of Astronomy and Astrophysics and Electro-Optic Systems (EOS) at Mount Stromlo Observatory, Canberra, Australia, as part of the Space Environment Management Cooperative Research Centre (SERC) to support the development in space situational awareness. Atmospheric turbulence leads to distortions in the measured data. Adaptive optics (AO) systems counteract those distortions and improve the resolution of the tracking and imaging systems. To assist in the design of the AO systems, we need to gather information on the atmosphere at Mount Stromlo: r0, τ 0, and the turbulence Cn2 profile. With the SCIntillation Detection And Ranging (SCIDAR) Technique the scintillation of two stars is measured and their autocorrelation function is computed, providing a measurement of the turbulence profile. This technique usually uses one detector recording the two images of the stars simultaneously. However, the images overlap leading to an underestimation of the Cn2 values. The introduction of stereo-SCIDAR1 over- comes this issue by separating the two stars and imaging them on two separate image sensors. To reduce costs, we introduce a new stereo-SCIDAR system separating the beams from the two stars, but using only one single detector. This has been shown for a Low Layer SCIDAR (LOLAS) system with wide double stars (200 arcsec). We investigate this technique by detecting the scintillation patterns of double stars with separation from 10 to 25 arcsec, allowing some flexibility in the altitude span and resolution, while retaining a simple optical setup. We selected a low noise sCMOS camera as the imager. We show the current design of this system and investigate its feasibility for further development.

  19. Visualising nursing data using correspondence analysis.

    Science.gov (United States)

    Kokol, Peter; Vošner, Helena Blažun; Železnik, Danica

    2016-09-01

    Background Digitally stored, large healthcare datasets enable nurses to use 'big data' techniques and tools in nursing research. Big data is complex and multi-dimensional, so visualisation may be a preferable approach to analyse and understand it. Aim To demonstrate the use of visualisation of big data in a technique called correspondence analysis. Discussion In the authors' study, relations among data in a nursing dataset were shown visually in graphs using correspondence analysis. The case presented demonstrates that correspondence analysis is easy to use, shows relations between data visually in a form that is simple to interpret, and can reveal hidden associations between data. Conclusion Correspondence analysis supports the discovery of new knowledge. Implications for practice Knowledge obtained using correspondence analysis can be transferred immediately into practice or used to foster further research.

  20. Parallel Access of Out-Of-Core Dense Extendible Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Otoo, Ekow J; Rotem, Doron

    2007-07-26

    Datasets used in scientific and engineering applications are often modeled as dense multi-dimensional arrays. For very large datasets, the corresponding array models are typically stored out-of-core as array files. The array elements are mapped onto linear consecutive locations that correspond to the linear ordering of the multi-dimensional indices. Two conventional mappings used are the row-major order and the column-major order of multi-dimensional arrays. Such conventional mappings of dense array files highly limit the performance of applications and the extendibility of the dataset. Firstly, an array file that is organized in say row-major order causes applications that subsequently access the data in column-major order, to have abysmal performance. Secondly, any subsequent expansion of the array file is limited to only one dimension. Expansions of such out-of-core conventional arrays along arbitrary dimensions, require storage reorganization that can be very expensive. Wepresent a solution for storing out-of-core dense extendible arrays that resolve the two limitations. The method uses a mapping function F*(), together with information maintained in axial vectors, to compute the linear address of an extendible array element when passed its k-dimensional index. We also give the inverse function, F-1*() for deriving the k-dimensional index when given the linear address. We show how the mapping function, in combination with MPI-IO and a parallel file system, allows for the growth of the extendible array without reorganization and no significant performance degradation of applications accessing elements in any desired order. We give methods for reading and writing sub-arrays into and out of parallel applications that run on a cluster of workstations. The axial-vectors are replicated and maintained in each node that accesses sub-array elements.

  1. Kinetic chemistry of dense interstellar clouds

    Energy Technology Data Exchange (ETDEWEB)

    Graedel, T.E.; Langer, W.D.; Frerking, M.A.

    1982-03-01

    A detailed model of the time-dependent chemistry of dense interstellar clouds has been developed to study the dominant chemical processes in carbon and oxygen isotope fractionation, formation of nitrogen-containing molecules, evolution of product molecules as a function of cloud density and temperature, and other topics of interest. The full computation involves 328 individual reactions (expanded to 1067 to study carbon and oxygen isotope chemistry); photodegradation processes are unimportant in these dense clouds and are excluded.

  2. Beam-excited whistler waves at oblique propagation with relation to STEREO radiation belt observations

    Directory of Open Access Journals (Sweden)

    K. Sauer

    2010-06-01

    Full Text Available Isotropic electron beams are considered to explain the excitation of whistler waves which have been observed by the STEREO satellite in the Earth's radiation belt. Aside from their large amplitudes (~240 mV/m, another main signature is the strongly inclined propagation direction relative to the ambient magnetic field. Electron temperature anisotropy with Te⊥>Te||, which preferentially generates parallel propagating whistler waves, can be excluded as a free energy source. The instability arises due to the interaction of the Doppler-shifted cyclotron mode ω=−Ωe+kVbcosθ with the whistler mode in the wave number range of kce≤1 (θ is the propagation angle with respect to the background magnetic field direction, ωe is the electron plasma frequency and Ωe the electron cyclotron frequency. Fluid and kinetic dispersion analysis have been used to calculate the growth rate of the beam-excited whistlers including the most important parameter dependencies. One is the beam velocity (Vb which, for instability, has to be larger than about 2VAe, where VAe is the electron Alfvén speed. With increasing VAe the propagation angle (θ of the fastest growing whistler waves shifts from θ~20° for Vb=2VAe to θ~80° for Vb=5VAe. The growth rate is reduced by finite electron temperatures and disappears if the electron plasma beta (βe exceeds βe~0.2. In addition, Gendrin modes (kce≈1 are analyzed to determine the conditions under which stationary nonlinear waves (whistler oscillitons can exist. The corresponding spatial wave profiles are calculated using the full nonlinear fluid approach. The results are compared with the STEREO satellite observations.

  3. Measurement of 3-D motion parameters of jacket launch based on stereo image sequences

    Institute of Scientific and Technical Information of China (English)

    HU Zhi-ping; OU Zong-ying; LIN Yan; LI Yun-feng

    2008-01-01

    To make sure that the process of jacket launch occurs in a semi-controlled manner, this paper deals with measurement of kinematic parameters of jacket launch using stereo vision and motion analysis. The system captured stereo image sequences by two separate CCD cameras, and then rebuilt 3D coordinates of the feature points to analyze the jacket launch motion. The possibility of combining stereo vision and motion analysis for measurement was examined. Results by experiments using scale model of jacket confirm the theoretical data.

  4. Distance stereo acuity improvement in intermittent exotropic patients following strabismus surgery.

    Science.gov (United States)

    O'Neal, T D; Rosenbaum, A L; Stathacopoulos, R A

    1995-01-01

    To determine whether distance stereo acuity improved following strabismus surgery in patients with intermittent exotropia, we tested 20 patients (5 to 87 years old) preoperatively and postoperatively using the Mentor BVAT II Video acuity tester (Santa Barbara, Calif) and binocular visual system. Acuity improved in 75% as assessed by contour circles and in 45% as assessed by random dot E tests at distance. Our results suggest that surgical realignment of intermittent exotropia restores distance stereo acuity. We conclude that measuring distance stereo acuity offers valuable information in the evaluation of the intermittent exotropic patient.

  5. Stereo sequences analysis for dynamic scene understanding in a driver assistance system

    Science.gov (United States)

    Vishnyakov, Boris V.; Vizilter, Yuri V.; Knyaz, Vladimir A.; Malin, Ivan K.; Vygolov, Oleg V.; Zheltov, Sergey Y.

    2015-05-01

    The improved stereo-based approach for dynamic road scene understanding in a Driver Assistance System (DAS) is presented. System calibration is addressed. Algorithms for road lane detection, road 3D model generation, obstacle predetection and object (vehicle) detection are described. Lane detection is based on the evidence analysis. Obstacle predetection procedure performs the comparison of radial ortophotos, obtained by left and right stereo images. Object detection algorithm is based on recognition of back part of cars by histograms of oriented gradients. Car Stereo Sequences (CSS) Dataset captured by vehicle-based laboratory and published for DAS algorithms testing.

  6. Molecular Dynamics for Dense Matter

    CERN Document Server

    Maruyama, Toshiki; Chiba, Satoshi

    2012-01-01

    We review a molecular dynamics method for nucleon many-body systems called the quantum molecular dynamics (QMD) and our studies using this method. These studies address the structure and the dynamics of nuclear matter relevant to the neutron star crusts, supernova cores, and heavy-ion collisions. A key advantage of QMD is that we can study dynamical processes of nucleon many-body systems without any assumptions on the nuclear structure. First we focus on the inhomogeneous structures of low-density nuclear matter consisting not only of spherical nuclei but also of nuclear "pasta", i.e., rod-like and slab-like nuclei. We show that the pasta phases can appear in the ground and equilibrium states of nuclear matter without assuming nuclear shape. Next we show our simulation of compression of nuclear matter which corresponds to the collapsing stage of supernovae. With increase of density, a crystalline solid of spherical nuclei change to a triangular lattice of rods by connecting neighboring nuclei. Finally, we dis...

  7. Coherence and correspondence in engineering design

    Directory of Open Access Journals (Sweden)

    Konstantinos V. Katsikopoulos

    2009-03-01

    Full Text Available I show how the coherence/correspondence distinction can inform the conversation about decision methods for engineering design. Some engineers argue for the application of multi-attribute utility theory while others argue for what they call heuristics. To clarify the differences among methods, I first ask whether each method aims at achieving coherence or correspondence. By analyzing statements in the design literature, I argue that utility theory aims at achieving coherence and heuristics aim at achieving correspondence. Second, I ask if achieving coherence always implies achieving correspondence. It is important to provide an answer because while in design the objective is correspondence, it is difficult to assess it, and coherence that is easier to assess is used as a surrogate. I argue that coherence does not always imply correspondence in design and that this is also the case in problems studied in judgment and decision-making research. Uncovering the conditions under which coherence implies, or does not imply, correspondence is a topic where engineering design and judgment and decision-making research might connect.

  8. Statistical characterization of short wind waves from stereo images of the sea surface

    Science.gov (United States)

    Mironov, Alexey; Yurovskaya, Maria; Dulov, Vladimir; Hauser, Danièle; Guérin, Charles-Antoine

    2013-04-01

    We propose a methodology to extract short-scale statistical characteristics of the sea surface topography by means of stereo image reconstruction. The possibilities and limitations of the technique are discussed and tested on a data set acquired from an oceanographic platform at the Black Sea. The analysis shows that reconstruction of the topography based on stereo method is an efficient way to derive non-trivial statistical properties of surface short- and intermediate-waves (say from 1 centimer to 1 meter). Most technical issues pertaining to this type of datasets (limited range of scales, lacunarity of data or irregular sampling) can be partially overcome by appropriate processing of the available points. The proposed technique also allows one to avoid linear interpolation which dramatically corrupts properties of retrieved surfaces. The processing technique imposes that the field of elevation be polynomially detrended, which has the effect of filtering out the large scales. Hence the statistical analysis can only address the small-scale components of the sea surface. The precise cut-off wavelength, which is approximatively half the patch size, can be obtained by applying a high-pass frequency filter on the reference gauge time records. The results obtained for the one- and two-points statistics of small-scale elevations are shown consistent, at least in order of magnitude, with the corresponding gauge measurements as well as other experimental measurements available in the literature. The calculation of the structure functions provides a powerful tool to investigate spectral and statistical properties of the field of elevations. Experimental parametrization of the third-order structure function, the so-called skewness function, is one of the most important and original outcomes of this study. This function is of primary importance in analytical scattering models from the sea surface and was up to now unavailable in field conditions. Due to the lack of precise

  9. Assessment of Correspondent Banks Case Study

    Directory of Open Access Journals (Sweden)

    Abeer F.A.A. Abbadi

    2011-01-01

    Full Text Available Problem statement: This study aims at evaluating corresponding banks in Jordan. Characterizing the goals, instruments and profitability under unfavorable conditions of financial setbacks and unfair competition among banks. Focuses on the feasibility and profitability of Philadelphia Investment Bank in its international trade via its Correspondent banks. Approach: Problems and setbacks shall be screened out; reasoned and appropriate optimal recommendations are to be presented. Results: The study followed the analytical approach and depended on “History Documents” and “In depth Interview” techniques and puts a major emphasis on the fact that correspondent banking has become an essential cornerstone of international business amid the new era of world trade, globalization, external competition and cartels from the major opponents to Jordanian Banks, the main conclusion is realized the importance of correspondent banks in the international trade, so Philadelphia bank benefited from correspondent banks for the cheap cost of market entry and services were tailored to the scale of required locale. But there was no big investment in staff facilities. And there are setbacks in dealing with correspondent banks, such as fund delay in reaching destinations on time. Moreover, Jordanian banks have suffered in general from these correspondent banks because they deal with these correspondent banks individually. Conclusion/Recommendations: The recommendation of the study is, it is the time to consider solidification and forming one financial block, or a sort of cartel and face these correspondent banks in one unit. They are also called for developing collective strategies. Small banks should merge and form huge capital blocks. Another strategy is that Jordanian banks should minimize the reliance on foreign banks and should develop their own, by establishing international branches abroad to help financing their international activities.

  10. Hawaiian Islands National Wildlife Refuge RAMOS correspondence

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document contains correspondence between John Findlay of the Bureau of Sport Fisheries and Wildlife and P. H. Kutschenreuter of the National Weather Service....

  11. The AdS/CFT correspondence

    Science.gov (United States)

    Hubeny, Veronika E.

    2015-06-01

    We give a brief review of the AdS/CFT correspondence, which posits the equivalence between a certain gravitational theory and a lower-dimensional non-gravitational one. This remarkable duality, formulated in 1997, has sparked a vigorous research program that has gained in breadth over the years, with applications to many aspects of theoretical (and even experimental) physics, not least to general relativity and quantum gravity. To put the AdS/CFT correspondence into historical context, we start by reviewing the relevant aspects of string theory (of which no prior knowledge is assumed). We then develop the statement of the correspondence, and explain how the two sides of the duality map into each other. Finally, we discuss the implications and applications of the correspondence, and indicate some of the current trends in this subject. The presentation attempts to convey the main concepts in a simple and self-contained manner, relegating supplementary remarks to footnotes.

  12. The AdS/CFT Correspondence

    CERN Document Server

    Hubeny, Veronika E

    2015-01-01

    We give a brief review of the AdS/CFT correspondence, which posits the equivalence between a certain gravitational theory and a lower-dimensional non-gravitational one. This remarkable duality, formulated in 1997, has sparked a vigorous research program which has gained in breadth over the years, with applications to many aspects of theoretical (and even experimental) physics, not least to general relativity and quantum gravity. To put the AdS/CFT correspondence in historical context, we start by reviewing the relevant aspects of string theory (of which no prior knowledge is assumed). We then develop the statement of the correspondence, and explain how the two sides of the duality map into each other. Finally, we discuss the implications and applications of the correspondence, and indicate some of the current trends in this subject. The presentation attempts to convey the main concepts in a simple and self-contained manner, relegating supplementary remarks to footnotes.

  13. Assessment of Correspondent Banks Case Study

    OpenAIRE

    Abeer F.A.A. Abbadi; Abdel N.T. Zyoud; Sinan S. Abbadi

    2011-01-01

    Problem statement: This study aims at evaluating corresponding banks in Jordan. Characterizing the goals, instruments and profitability under unfavorable conditions of financial setbacks and unfair competition among banks. Focuses on the feasibility and profitability of Philadelphia Investment Bank in its international trade via its Correspondent banks. Approach: Problems and setbacks shall be screened out; reasoned and appropriate optimal recommendations are to be presented. Results: The stu...

  14. Thermodynamic Properties from Corresponding States Theory

    DEFF Research Database (Denmark)

    Mollerup, Jørgen

    1980-01-01

    —Leland corresponding-states theory. Different fluid approximations for mixtures have been applied to the various corresponding states approaches. The resulting computation methods have been applied to calculate saturation properties of pure fluids and separation factors in binary mixtures for some fluids commonly...... encountered in natural gas and petroleum refining operations. Finally it is shown that the binary interaction parameters depend only on the fluid approximation and not on the specific form of the potential....

  15. Tag Correspondence Model for User Tag Suggestion

    Institute of Scientific and Technical Information of China (English)

    涂存超; 刘知远; 孙茂松

    2015-01-01

    Some microblog services encourage users to annotate themselves with multiple tags, indicating their attributes and interests. User tags play an important role for personalized recommendation and information retrieval. In order to better understand the semantics of user tags, we propose Tag Correspondence Model (TCM) to identify complex correspondences of tags from the rich context of microblog users. The correspondence of a tag is referred to as a unique element in the context which is semantically correlated with this tag. In TCM, we divide the context of a microblog user into various sources (such as short messages, user profile, and neighbors). With a collection of users with annotated tags, TCM can automatically learn the correspondences of user tags from multiple sources. With the learned correspondences, we are able to interpret implicit semantics of tags. Moreover, for the users who have not annotated any tags, TCM can suggest tags according to users’ context information. Extensive experiments on a real-world dataset demonstrate that our method can effciently identify correspondences of tags, which may eventually represent semantic meanings of tags.

  16. MISR Level 2 FIRSTLOOK TOA/Cloud Stereo parameters V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This is the Level 2 FIRSTLOOK TOA/Cloud Stereo Product. It contains the Stereoscopically Derived winds, heights and cloud mask along with associated data, produced...

  17. Passive Night Vision Sensor Comparison for Unmanned Ground Vehicle Stereo Vision Navigation

    Science.gov (United States)

    Owens, Ken; Matthies, Larry

    2000-01-01

    One goal of the "Demo III" unmanned ground vehicle program is to enable autonomous nighttime navigation at speeds of up to 10 m.p.h. To perform obstacle detection at night with stereo vision will require night vision cameras that produce adequate image quality for the driving speeds, vehicle dynamics, obstacle sizes, and scene conditions that will be encountered. This paper analyzes the suitability of four classes of night vision cameras (3-5 micrometer cooled FLIR, 8-12 micrometer cooled FLIR, 8-12 micrometer uncooled FLIR, and image intensifiers) for night stereo vision, using criteria based on stereo matching quality, image signal to noise ratio, motion blur and synchronization capability. We find that only cooled FLIRs will enable stereo vision performance that meets the goals of the Demo III program for nighttime autonomous mobility.

  18. A study on the effect of different image centres on stereo triangulation accuracy

    CSIR Research Space (South Africa)

    De Villiers, J

    2015-11-01

    Full Text Available This paper evaluates the effect of mixing the distortion centre, principal point and arithmetic image centre on the distortion correction, focal length determination and resulting real-world stereo vision triangulation. A robotic arm is used...

  19. An overview of the stereo correlation and triangulation formulations used in DICe.

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Daniel Z. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-02-01

    This document provides a detailed overview of the stereo correlation algorithm and triangulation formulation used in the Digital Image Correlation Engine (DICe) to triangulate three dimensional motion in space given the image coordinates and camera calibration parameters.

  20. Analysis and measure of novel stereo-garage driven by linear induction motor

    Directory of Open Access Journals (Sweden)

    Lu Qinfen

    2015-12-01

    Full Text Available The car access time is a key parameter, especially in a huge stereo-garage, where this one should be decreased as much as possible. This paper proposes a novel stereo-garage. Adopting the linear induction motors (LIMs, the system has a simple structure and rapid response capability. In the stereo-garage, several LIMs are installed below the crossbeam on a lifting platform, and several LIMs are fixed on the top of a moving frame. During the operation of LIMs, the moving frame moves forward and backward to reach the required parking place, whereas the crossbeam moves horizontally in order to take or store the vehicle rapidly. All these LIMs are the same and should be designed at a low frequency. The influences of key structure parameters and dynamic performances are investigated, based on FEM. The predicted results are validated by a prototype. Finally, the designed LIMs are successfully applied in two 8-layer stereo-garages.

  1. A Stereo-Vision Based Hazard-Detection Algorithm for Future Planetary Landers

    Science.gov (United States)

    Woicke, S.; Mooij, E.

    2014-06-01

    A hazard detection algorithm based on the stereo-vision principle is presented. A sensitivity analysis concerning the minimum baseline and the maximum altitude is discussed, based on which the limitations of this algorithm are investigated.

  2. A 3D Scene Graph Cut-Based Dense Reconstruction Algorithm%一种基于图割的稠密三维场景重建算法

    Institute of Scientific and Technical Information of China (English)

    徐刚; 刘彬; 李海滨

    2011-01-01

    Stereo vision plays a very important role in environment perception of the autonomous exploration robot, by which the dense reconstruction result of the 3D scene can be derived. In this paper, the candidate matching algorithm combined with graph cut theory is proposed to solve the stereo correspondence problem. First, the mesh grid representing depth is constructed in the world coordinate system. Second, most of the candidates can be pruned according to an area matching algorithm, and the remaining nodes are used to form a graph. Finally, the global energy minimization could be achieved by finding minimum cut in the graph, and the 3D scene reconstruction would be fulfilled. The experimental result shows that a tradeoff between performance and efficiency could be achieved when threshold y was set to 0.6. The problem of matching ambiguity is solved by using the graph cut algorithm, and a better performance can be achieved in coarse texture region.%立体视觉技术是自主探测机器人在未知环境中获取信息的重要手段,通过对可视场景的稠密三维重建实现导航、定位及路径规划等一系列工作.本文在候选点匹配的基础上结合图割理论,首先在世界坐标系建立代表深度信息的网格节点,接着依据区域匹配算法对候选点进行初步筛选,去除大部分相关值较低的节点,建立简化的网格图,最后通过寻找图中最小割来实现能量函数的全局最小,完成稠密的三维场景重建.实验证明,相关阈值γ设为0.6时,简化网格图的重建精度和计算效率达到相对平衡.图割算法解决了候选点测量时潜在的匹配歧义问题,且对低纹理区域有较好的匹配效果.

  3. Double biprism arrays design using for stereo-photography of mobile phone camera

    Science.gov (United States)

    Sun, Wen-Shing; Chu, Pu-Yi; Chao, Yu-Hao; Pan, Jui-Wen; Tien, Chuen-Lin

    2016-11-01

    Generally, mobile phone use one camera to catch the image, and it is hard to get stereo image pair. Adding a biprism array can help that get the image pair easily. So users can use their mobile phone to catch the stereo image anywhere by adding a biprism array, and if they want to get a normal image just remove it. Using biprism arrays will induce chromatic aberration. Therefore, we design a double biprism arrays to reduce chromatic aberration.

  4. Development and Application of the Stereo Vision Tracking System with Virtual Reality

    OpenAIRE

    Chia-Sui Wang; Ko-Chun Chen; Tsung Han Lee; Kuei-Shu Hsu

    2015-01-01

    A virtual reality (VR) driver tracking verification system is created, of which the application to stereo image tracking and positioning accuracy is researched in depth. In the research, the feature that the stereo vision system has image depth is utilized to improve the error rate of image tracking and image measurement. In a VR scenario, the function collecting behavioral data of driver was tested. By means of VR, racing operation is simulated and environmental (special weathers such as rai...

  5. Automatic 3D reconstruction of quasi-planar stereo Scanning Electron Microscopy (SEM) images.

    Science.gov (United States)

    Roy, S; Meunier, J; Marian, A M; Vidal, F; Brunette, I; Costantino, S

    2012-01-01

    Scanning Electron Microscopy (SEM) is widely used in science to characterize the surface roughness of materials. Three-dimensional information can be obtained with SEM based on stereovision techniques. A stereo pair is typically obtained by tilting the sample by a few degrees. In this paper we present a fully automated method for 3D reconstruction from a SEM stereo pair without any particular constraint. Results are presented for corneal stromal surfaces.

  6. Extracting Accurate and Precise Topography from Lroc Narrow Angle Camera Stereo Observations

    Science.gov (United States)

    Henriksen, M. R.; Manheim, M. R.; Speyerer, E. J.; Robinson, M. S.; LROC Team

    2016-06-01

    The Lunar Reconnaissance Orbiter Camera (LROC) includes two identical Narrow Angle Cameras (NAC) that acquire meter scale imaging. Stereo observations are acquired by imaging from two or more orbits, including at least one off-nadir slew. Digital terrain models (DTMs) generated from the stereo observations are controlled to Lunar Orbiter Laser Altimeter (LOLA) elevation profiles. With current processing methods, digital terrain models (DTM) have absolute accuracies commensurate than the uncertainties of the LOLA profiles (~10 m horizontally and ~1 m vertically) and relative horizontal and vertical precisions better than the pixel scale of the DTMs (2 to 5 m). The NAC stereo pairs and derived DTMs represent an invaluable tool for science and exploration purposes. We computed slope statistics from 81 highland and 31 mare DTMs across a range of baselines. Overlapping DTMs of single stereo sets were also combined to form larger area DTM mosaics, enabling detailed characterization of large geomorphic features and providing a key resource for future exploration planning. Currently, two percent of the lunar surface is imaged in NAC stereo and continued acquisition of stereo observations will serve to strengthen our knowledge of the Moon and geologic processes that occur on all the terrestrial planets.

  7. Estimation of Aboveground Biomass Using Manual Stereo Viewing of Digital Aerial Photographs in Tropical Seasonal Forest

    Directory of Open Access Journals (Sweden)

    Katsuto Shimizu

    2014-11-01

    Full Text Available The objectives of this study are to: (1 evaluate accuracy of tree height measurements of manual stereo viewing on a computer display using digital aerial photographs compared with airborne LiDAR height measurements; and (2 develop an empirical model to estimate stand-level aboveground biomass with variables derived from manual stereo viewing on the computer display in a Cambodian tropical seasonal forest. We evaluate observation error of tree height measured from the manual stereo viewing, based on field measurements. RMSEs of tree height measurement with manual stereo viewing and LiDAR were 1.96 m and 1.72 m, respectively. Then, stand-level aboveground biomass is regressed against tree height indices derived from the manual stereo viewing. We determined the best model to estimate aboveground biomass in terms of the Akaike’s information criterion. This was a model of mean tree height of the tallest five trees in each plot (R2 = 0.78; RMSE = 58.18 Mg/ha. In conclusion, manual stereo viewing on the computer display can measure tree height accurately and is useful to estimate aboveground stand biomass.

  8. Some comparisons of binaural measurements made with different dummy heads and stereo microphone techniques

    Science.gov (United States)

    Mapp, Peter A.

    2004-10-01

    Binaural measurements have been made in a number of acoustic environments, and the results from different binaural heads and stereo microphones are compared. The object of the study was not only to establish what practical differences occurred between the various head formats, but also to see if a stereo microphone or pseudohead could be used for making auditorium binaural measurements. Five measurement platforms were employed. These included two binaural dummy heads, binaural in-ear probe microphones, an SAAS pseudohead stereo microphone and a M-S (midside) stereo microphone. In the latter case, three different midside ratios were employed and compared. The measurements were made in a reverberant recital hall (2.5-s RT) and small acoustically treated listening room (RT 0.2 s). Whereas relatively minor differences were found to occur between the heads, significant differences were found to occur with the stereo microphones. It is concluded that while useful information can be obtained from a stereo microphone, it is far from being the same as binaural.

  9. Transformation of Correspondence Education into Distance Education

    Directory of Open Access Journals (Sweden)

    Marjan Velej

    1997-12-01

    Full Text Available Since 1957 the Correspondence-Education Centre Univerzum has been involved in correspondence education, which - as a matter of principle - uses the written word as a basic and predorninam medium of instruction, ensuring a two­ directional communication between the teacher and the student. Following the world-wide trends in adult education, the institution has gradually updated its teaching methods by incorporating correspondence-consulting and correspondence-seminar methods. As a result of the forceful development of new technologies and media the written word has become only one among many media of instruction, replacing the concept of correspon­ dence education with that of distance education. Although the latter hasa num­ ber of advantages, it is rather difficult to implement. ln view of its role and in the interese of its own development, the Correspondence-Education Centre Univerzum is forced to effect the transition to distance education. In order to be able to effectively adopt new methods, extensive training has been organised for the teaching staff, the results of which are encouraging. They enable us to plan further changes and improvements of our methods of instruction.

  10. Injection of photoelectrons into dense argon gas

    CERN Document Server

    Borghesani, A F

    2010-01-01

    The injection of photoelectrons in a gaseous or liquid sample is a widespread technique to produce a cold plasma in a weakly--ionized system in order to study the transport properties of electrons in a dense gas or liquid. We report here the experimental results of photoelectron injection into dense argon gas at the temperatureT=142.6 K as a function of the externally applied electric field and gas density. We show that the experimental data can be interpreted in terms of the so called Young-Bradbury model only if multiple scattering effects due to the dense environment are taken into account when computing the scattering properties and the energetics of the electrons.

  11. AUOTOMATIC CLASSIFICATION OF POINT CLOUDS EXTRACTED FROM ULTRACAM STEREO IMAGES

    OpenAIRE

    M. Modiri; Masumi, M.; A. Eftekhari

    2015-01-01

    Automatic extraction of building roofs, street and vegetation are a prerequisite for many GIS (Geographic Information System) applications, such as urban planning and 3D building reconstruction. Nowadays with advances in image processing and image matching technique by using feature base and template base image matching technique together dense point clouds are available. Point clouds classification is an important step in automatic features extraction. Therefore, in this study, the classific...

  12. Black Hole Formation at the Correspondence Point

    CERN Document Server

    Iizuka, Norihiro; Roy, Shubho; Sarkar, Debajyoti

    2013-01-01

    We study the process of bound state formation in a D-brane collision. We consider two mechanisms for bound state formation. The first, operative at weak coupling in the worldvolume gauge theory, is pair creation of W-bosons. The second, operative at strong coupling, corresponds to formation of a large black hole in the dual supergravity. These two processes agree qualitatively at intermediate coupling, in accord with the correspondence principle of Horowitz and Polchinski. We show that the size of the bound state and timescale for formation of a bound state agree at the correspondence point. The timescale involves matching a parametric resonance in the gauge theory to a quasinormal mode in supergravity.

  13. Soft-/rapidity- anomalous dimensions correspondence

    CERN Document Server

    Vladimirov, Alexey A

    2016-01-01

    We establish a correspondence between ultraviolet singularities of soft factors for multi-particle production and rapidity singularities of soft factors for multi-parton scattering. This correspondence is a consequence of a conformal mapping between scattering geometries. The correspondence is valid to all orders of perturbation theory and in this way provides a proof of rapidity renormalization procedure for multi-parton scattering soft factors (including the transverse momentum dependent (TMD) soft factor as a special case). As a by-product we obtain an exact relation between the rapidity anomalous dimension and the well-known soft anomalous dimension. The three-loop rapidity anomalous dimensions for TMD and a general multi-parton scattering are derived.

  14. Searching for coherence in a correspondence world

    Directory of Open Access Journals (Sweden)

    Kathleen L. Mosier

    2009-03-01

    Full Text Available In this paper, I trace the evolution of the aircraft cockpit as an example of the transformation of a probabilistic environment into an ecological hybrid, that is, an environment characterized by both probabilistic and deterministic features and elements. In the hybrid ecology, the relationships among correspondence and coherence strategies and goals and cognitive tactics on the continuum from intuition to analysis become critically important. Intuitive tactics used to achieve correspondence in the physical world do not work in the electronic world. Rather, I make the case that judgment and decision making in a hybrid ecology requires extit{coherence} as the primary strategy to achieve extit{correspondence}, and that this process requires a shift in tactics from intuition toward analysis.

  15. Fully Automatic Expression-Invariant Face Correspondence

    CERN Document Server

    Salazar, Augusto; Shu, Chang; Prieto, Flavio

    2012-01-01

    We consider the problem of computing accurate point-to-point correspondences among a set of human face scans with varying expressions. Our fully automatic approach does not require any manually placed markers on the scan. Instead, the approach learns the locations of a set of landmarks present in a database and uses this knowledge to automatically predict the locations of these landmarks on a newly available scan. The predicted landmarks are then used to compute point-to-point correspondences between a template model and the newly available scan. To accurately fit the expression of the template to the expression of the scan, we use as template a blendshape model. Our algorithm was tested on a database of human faces of different ethnic groups with strongly varying expressions. Experimental results show that the obtained point-to-point correspondence is both highly accurate and consistent for most of the tested 3D face models.

  16. Eigenvalues properties of terms correspondences matrix

    Science.gov (United States)

    Bondarchuk, Dmitry; Timofeeva, Galina

    2016-12-01

    Vector model representations of text documents are widely used in the intelligent search. In this approach a collection of documents is represented in the form of the term-document matrix, reflecting the frequency of terms. In the latent semantic analysis the dimension of the vector space is reduced by the singular value decomposition of the term-document matrix. Authors use a matrix of terms correspondences, reflecting the relationship between the terms, to allocate a semantic core and to obtain more simple presentation of the documents. With this approach, reducing the number of terms is based on the orthogonal decomposition of the matrix of terms correspondences. Properties of singular values of the term-document matrix and eigenvalues of the matrix of terms correspondences are studied in the case when documents differ substantially in length.

  17. BUSINESS COMMUNICATION AND ITALIAN COMMERCIAL CORRESPONDENCE

    Directory of Open Access Journals (Sweden)

    SILVIA MADINCEA PAȘCU

    2012-05-01

    Full Text Available Despite more frequent use of e-mails, fax messages, or memos, letters still have their role in trade. At the same time, this form of correspondence adapts itself to current times, with the purpose of not being eliminated by "competition", adopting new formats and structures.The present paper tries to make a brief presentation of the main means of communication, with a particular accent on business correspondence.A detailed description will be given to the types of Italian business letters (circulars, bids, requests, orders, etc., to their subcategories (external and internal circulars, offers of goods and services etc., to their aesthetic format and to their structures.

  18. Exact Classical Correspondence in Quantum Cosmology

    CERN Document Server

    John, Moncy V

    2014-01-01

    We find a Friedmann model with appropriate matter/energy density such that the solution of the Wheeler-DeWitt equation exactly corresponds to the classical evolution. The well-known problems in quantum cosmology disappear in the resulting coasting evolution. The exact quantum-classical correspondence is demonstrated with the help of the de Broglie-Bohm and modified de Broglie-Bohm approaches to quantum mechanics. It is reassuring that such a solution leads to a robust model for the universe, which agrees well with cosmological expansion indicated by SNe Ia data.

  19. An Omnidirectional Stereo Vision-Based Smart Wheelchair

    Directory of Open Access Journals (Sweden)

    Yutaka Satoh

    2007-06-01

    Full Text Available To support safe self-movement of the disabled and the aged, we developed an electric wheelchair that realizes the functions of detecting both the potential hazards in a moving environment and the postures and gestures of a user by equipping an electric wheelchair with the stereo omnidirectional system (SOS, which is capable of acquiring omnidirectional color image sequences and range data simultaneously in real time. The first half of this paper introduces the SOS and the basic technology behind it. To use the multicamera system SOS on an electric wheelchair, we developed an image synthesizing method of high speed and high quality and the method of recovering SOS attitude changes by using attitude sensors is also introduced. This method allows the SOS to be used without being affected by the mounting attitude of the SOS. The second half of this paper introduces the prototype electric wheelchair actually manufactured and experiments conducted using the prototype. The usability of the electric wheelchair is also discussed.

  20. Simultaneous dual-energy X-ray stereo imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mokso, Rajmund, E-mail: rajmund.mokso@psi.ch [Paul Scherrer Institute, Swiss Light Source, CH 5232 Villigen (Switzerland); Oberta, Peter [Institute of Physics of the Academy of Sciences of the Czech Republic, v.v.i., Na Slovance 1999/2, Praha 8 (Czech Republic); Rigaku Innovative Technologies Europe s.r.o., Novodvorska 994, Praha 4 (Czech Republic)

    2015-06-26

    A Laue–Bragg geometry is introduced for splitting an X-ray beam and tuning each of the two branches to selected wavelength. Stereoscopic and dual-energy imaging was performed with this system. Dual-energy or K-edge imaging is used to enhance contrast between two or more materials in an object and is routinely realised by acquiring two separate X-ray images each at different X-ray wavelength. On a broadband synchrotron source an imaging system to acquire the two images simultaneously was realised. The single-shot approach allows dual-energy and stereo imaging to be applied to dynamic systems. Using a Laue–Bragg crystal splitting scheme, the X-ray beam was split into two and the two beam branches could be easily tuned to either the same or to two different wavelengths. Due to the crystals’ mutual position, the two beam branches intercept each other under a non-zero angle and create a stereoscopic setup.