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The following topics are discussed: computer vision and image analysis; face and human analysis; face recognition; character recognition and document analysis; clustering algorithms; signal, speech and image processing; signal coding and compression; document image enhancement; visualization and restoration; systems, robotics and applications; biometrics; biomedical imaging; fingerprints; range imaging...
High resolution aerial and satellite images of forests have a key role to play in natural resource management. As they enable to study forests at the scale of trees, it is now possible to get a more accurate evaluation of the forest resources, from which can be deduced information on biodiversity and ecological sustainability. In that prospect, automatic algorithms are needed to give a further exploitation...
We augment the tensor voting framework with a data-driven multiscale scheme for reconstructing a multiresolution mesh from a noisy 3D point set. The augmentations are effective, automatic but very simple, consisting of surface saliency inference, scale segmentation, and data normalization. These data analysis steps enable tensor voting to operate at a single scale in each normalized data segment,...
In this paper we present a novel volumetric shape from silhouette algorithm based on a centripetal pentahedron model. The algorithm first partitions the space with a set of infinite triangular pyramids derived from a geodesic sphere. Then the pyramids are cut by silhouettes into a set of pentahedrons, which together constitute the centripetal pentahedron model of the visual hull. This process is accelerated...
Recently, projector camera systems have been studied extensively for designing man machine interaction systems. In this paper, we propose a new method for calibrating uncalibrated projector camera systems. In particular, we show that it is possible to calibrate camera projector systems projectively and reconstruct 3D information reliably by using shadows of objects made by projector lights. We also...
In this paper, a model is proposed for partitioning of 3D objects based on Reeb graphs. The model is motivated by perceptual principles and supports identification of the main protrusions of an object. Experimental results are presented to demonstrate the effectiveness of the proposed solution with respect to ground-truth data represented by manually segmented objects
Terrestrial laser scanners produce point clouds with a huge number of points within a very limited surrounding. In built-up areas, many of the man-made objects are dominated by planar surfaces. We introduce a RANSAC based preprocessing technique that transforms the irregular point cloud into a set of locally delimited surface patches in order to reduce the amount of data and to achieve a higher level...
In the present paper, we propose a method for reconstructing the surfaces of objects from stereovision data. Both the fitness of stereo data to surfaces and interrelation between the surfaces are defined in the framework of a three-dimensional (3D) Markov random field (MRF) model. The surface reconstruction is accomplished by searching for the most likely state of the MRF model. An experimental result...
In a practical video encoder, a video sequence obtained from a CCD camera inevitably conveys noise, which degrades not only image quality but also coding efficiency. Based on the statistic analysis of noise signal, a noise variance adaptive two-stage successive elimination algorithm (NVA-SEA) for block motion estimation is presented. Simulation results demonstrate that the proposed algorithm can get...
We study the motion estimation across three images by simultaneously enforcing the geometric constraint of trilinearity and the constant-brightness constraint. An iterative and hierarchical three-frame scheme is proposed to solve the geometry-consistent and appearance-consistent motion fields. It provides an uncalibrated approach to dense motion estimation, applicable to both 2D and 3D rigid scenes...
This paper proposes how the classic factorisation algorithm for affine reconstruction can be extended to be robust to outliers and proposes how the uncertainty analysis can be performed in this case. The robust estimation approach elaborated here is based on the iteratively re-weighted least-squares but the use of other robust methods is also discussed. Moreover, the uncertainty analysis presented...
A method is proposed for performing shape analysis of m-surfaces, e.g. planar curves and surfaces, with a geometric interpretation. The analysis uses an implicit surface representation and connects the popular level set approach with shape analysis. The representation is continuous and completely landmark-free. Shapes are represented as points on an infinite-dimensional manifold and the distance between...
In this paper, we propose a symmetric pixel-group stereo model for handling occlusion in a segment-based style. Firstly, both images are segmented based on color, disparity, and the segments of the other image sequencely. Then the uniqueness constraint is embodied in pixel-group level. Finally, a symmetric belief propagation (BP) optimization framework is used to find correspondence and occlusions...
An algorithm for automatic estimation of 3D transformations between two objects is presented in this paper. Skeletons of the 3D objects are created using a fully parallel thinning technique, feature point pairs (land markers) are automatically extracted from skeletons, and a least squares method is applied to solve an over determined linear system to estimate the 3D transformation matrix. Experiments...
This paper describes an ultra-fast method for estimation of translational motion in video sequences. The method is based on the principle that 2D image translation results in translation of image projections. To obtain superior robustness and accuracy we developed a multi-frame extension, which robustly integrates motion information over time. Our method gives reliable results even when video images...
Graph-spectral surface integration techniques construct an integration path assuming that the surface contains a path along which the integration error is minimal. This paper presents a generalisation that uses Minimum Spanning Trees of the weighted grid graph of surface normals, which scales with no need for surface segmentation. The problem of choosing an integration path is reduced to defining...
This paper introduces an efficient 3D segmentation concept, which is based on extending the well-known maximally stable extremal region (MSER) detector to the third dimension. The extension allows the detection of stable 3D regions, which we call the maximally stable volumes (MSVs). We present a very efficient way to detect the MSVs in quasi-linear time by analysis of the component tree. Two applications...
Generic camera modeling using raxels and associated methods was recently introduced in computer vision. The main advantage is the applicability for any camera model, which contrasts to the many specific methods designed for a single camera model. This paper introduces a bundle adjustment based on angular error for the generic structure from motion problem. Experiments include automatic, robust and...
In a previous paper, we showed that a 3D object can be digitized without changing the topology if the object is r-regular and if the reconstruction method fulfills certain requirements. In this paper, we give two important examples for such reconstruction methods. First, we introduce majority interpolation, an algorithm to interpolate sampling points at doubled resolution such that topological ambiguities...
This paper describes a method for detecting 3D-flow of an arbitrary point on a free-form surface from time series range images obtained by a stereovision system. The approach that positively uses surface shape data obtained from the range images is examined. Especially, it proposes height-color-histogram (HCH) that integrates local convex-concave shape and color texture information on the surface...
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