A method based on the extended Gaussian image (EGI) which can be used to determine the pose of a 3-D object is presented. In this scheme, the weight associated with each outward surface normal is a complex weight. The...
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ISBN:
(纸本)0818621486
A method based on the extended Gaussian image (EGI) which can be used to determine the pose of a 3-D object is presented. In this scheme, the weight associated with each outward surface normal is a complex weight. The normal distance of the surface from the predefined origin is encoded as the phase of the weight, while the magnitude of the weight is the visible area of the surface. This approach decouples the orientation and translation determination into two distinct least-squares problems. Experiments involving synthetic data of two polyhedral and two smooth objects as well as real range data of the same smooth objects indicate the feasibility of this method.
It is suggested that non-smooth or complex boundaries are processed by the visual system so as to obtain a simple abstract description, called contour texture, which contains much less information than that provided b...
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ISBN:
(纸本)0818621486
It is suggested that non-smooth or complex boundaries are processed by the visual system so as to obtain a simple abstract description, called contour texture, which contains much less information than that provided by the location of all points of the contour. A discussion is presented of what the nature of the contour texture of a curve is and its relation with two-dimensional texture, which the author contends should be thought of as a separate concept. Several applications are suggested, and an implemented filter-based scheme is presented.
A solution to the correspondence problem using constraint satisfaction is described. It uses a real-time line-fitting algorithm to detect changes in a point's motion parameters as they happen. A trajectory is hypo...
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ISBN:
(纸本)0818621486
A solution to the correspondence problem using constraint satisfaction is described. It uses a real-time line-fitting algorithm to detect changes in a point's motion parameters as they happen. A trajectory is hypothesized for a single point's motion. Since the event detected may be wrong, multiple trajectories are hypothesized for each point. A correspondence is drawn from the set of hypothesized trajectories. The algorithm is robust, working on noisy and non-rigid motion data, and does not use false precision.
An approach for representing signatures in an offline environment is presented. The approach first makes a tracing of a signature similar to the way a human normally does, using hierarchical decision-making for stroke...
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ISBN:
(纸本)0818621486
An approach for representing signatures in an offline environment is presented. The approach first makes a tracing of a signature similar to the way a human normally does, using hierarchical decision-making for stroke identification and ordering based on a set of heuristic rules. The dynamic information from the tracing sequence is then incorporated into the representation of the signature. A multiresolution critical-point segmentation method is used to extract local feature points, at varying degrees of scale and coarseness, for subsequent representation of the signature. Experimental results are discussed.
A hierarchical stereo system is described that uses structural descriptions up to the surface level. Surface descriptions are computed from monocular images by using a perceptual grouping technique. Occlusion can be a...
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ISBN:
(纸本)0818621486
A hierarchical stereo system is described that uses structural descriptions up to the surface level. Surface descriptions are computed from monocular images by using a perceptual grouping technique. Occlusion can be a major problem in stereo analysis and is often not treated explicity. An analysis is presented of occlusion effects in stereo, and it is shown how structural descriptions can be used to deal with them. Experimental results are given for scenes with curved objects and significant occlusions.
A novel approach to incrementally estimating visual motion over a sequence of images is presented. The authors start by formulating constraints on image motion to account for the possibility of multiple motions. This ...
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ISBN:
(纸本)0818621486
A novel approach to incrementally estimating visual motion over a sequence of images is presented. The authors start by formulating constraints on image motion to account for the possibility of multiple motions. This is achieved by exploiting the notions of weak continuity and robust statistics in the formulation of a minimization problem. The resulting objective function is non-convex. Traditional stochastic relaxation techniques for minimizing such functions prove inappropriate for the task. A highly parallel incremental stochastic minimization algorithm is presented which has a number of advantages over previous approaches. The incremental nature of the scheme makes it dynamic and permits the detection of occlusion and disocclusion boundaries.
A multidimensional edge model is established and a first-order estimation for multidimensional edge profiles is proposed. An optimal edge location detection algorithm is developed. The advantages of the algorithm are ...
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ISBN:
(纸本)0818621486
A multidimensional edge model is established and a first-order estimation for multidimensional edge profiles is proposed. An optimal edge location detection algorithm is developed. The advantages of the algorithm are that (1) it has little dependence on assumptions of edge models, noise models, or smoothing filters, (2) it has better abilities for detecting very weak edges and making less edge orientation errors than other edge detectors, (3) it can handle corners and complicated multidimensional image structures, and (4) it detects different edge types at the same time.
Two complementary methods for the detection of moving objects by a moving observer are described. The first (constraint ray filtering) uses a constraint that restricts the projected velocity at any image point to a 1-...
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ISBN:
(纸本)0818621486
Two complementary methods for the detection of moving objects by a moving observer are described. The first (constraint ray filtering) uses a constraint that restricts the projected velocity at any image point to a 1-D locus in velocity space to detect motion inconsistant with a rigid world assumption. The second (animate motion detection) utilizes a constraint on the time-rate-of-change of projected velocity due to smooth observer motion to detect moving objects such as animals and maneuvering vehicles whose projected motion changes rapidly. In both cases, the qualitative nature of the constraints allows the methods to be used with the inexact motion information typically available from real image sequences. Implementations of the methods that run in real time on a parallel pipelined imageprocessing system are described.
Rigid 3-D objects were modeled automatically from an image sequence taken by a camera that was rotated around the object. The image sequence was recorded using a calibrated camera which allows one to measure the camer...
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ISBN:
(纸本)0818621486
Rigid 3-D objects were modeled automatically from an image sequence taken by a camera that was rotated around the object. The image sequence was recorded using a calibrated camera which allows one to measure the camera positions and to estimate the true object size. The 3-D object shape was obtained in two steps. The object silhouettes were employed to find the enclosing volume of the object. The volume was converted into a flexible surface representation and the 3-D shape was refined based on the texture information of the object surface. Texture mapping was applied to generate a highly realistic 3-D model of the object.
The surface reconstruction problem is formulated as a two-stage reconstruction procedure. The first stage is a robust local fit to the data in a multiresolution scheme and the second is a regularized least squares fit...
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ISBN:
(纸本)0818621486
The surface reconstruction problem is formulated as a two-stage reconstruction procedure. The first stage is a robust local fit to the data in a multiresolution scheme and the second is a regularized least squares fit with the addition of an adaptive mechanism in the smoothness functional in order to make the solution well behaved. The authors present the details of the second stage in which they use the weighted bicubic spline as a surface representation in a regularization framework, with a Tikhonov stabilizer as the smoothness norm. It is shown how the adaptive weights in the stabilizer help the surface bend across discontinuities by varying the energy of the surface.
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