A description is given of the construction of a symmetry analyzer. Examples using SYMAN on both real and synthetic images are shown. SYMAN's combination of both global and local methods is discussed. The derivatio...
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ISBN:
(纸本)0818621486
A description is given of the construction of a symmetry analyzer. Examples using SYMAN on both real and synthetic images are shown. SYMAN's combination of both global and local methods is discussed. The derivation of a global analytic solution for the skew axes when the degree of skew symmetry is known is described. A local tangent-based algorithm which has advantages over previous methods is presented.
A model-based recognition method that runs in time proportional to the actual number of instances of a model that are found in an image is presented. The key idea is to filter out many of the possible matches without ...
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ISBN:
(纸本)0818621486
A model-based recognition method that runs in time proportional to the actual number of instances of a model that are found in an image is presented. The key idea is to filter out many of the possible matches without having to explicity consider each one. This contrasts with the hypothesize-and-test paradigm, commonly used in model-based recognition, where each possible match is tested and either accepted or rejected. For most recognition problems the number of possible matches is very large, whereas the number of actual matches is quite small, making output-sensitive methods such as this one very attractive. The method is based on an affine invariant representation of an object that uses distance ratios defined by quadruples of feature points. A central property of this representation is that it can be recovered from an image using only pairs of feature points.
A framework is presented for segmenting shallow structures from their background over a sequence of images. Shallowness is first quantified as affine describability. This is embedded in a tracking system within which ...
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ISBN:
(纸本)0818621486
A framework is presented for segmenting shallow structures from their background over a sequence of images. Shallowness is first quantified as affine describability. This is embedded in a tracking system within which hypothesized model structures undergo a cycle of prediction and model-matching. Structures emerge either as shallow or non-shallow based on their affine trackability. This work rejects continuity heuristics for purely image motion in favor of temporal continuity defined as the consistency of generic 3-D models, namely shallow structures.
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.
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.
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.
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.
Detection and thresholding using a stochastic approach is discussed. A general form of detectors which includes a number of well-known detectors as special cases is discussed. Thresholding is indispensable to eliminat...
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ISBN:
(纸本)0818621486
Detection and thresholding using a stochastic approach is discussed. A general form of detectors which includes a number of well-known detectors as special cases is discussed. Thresholding is indispensable to eliminate spurious responses from the detection process. The authors propose a weighted thresholding, which is designed to cope with a variety of anomalies. The analysis and experimental results on real images show that intelligent thresholding methods can make a significant difference for discontinuity detection.
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.
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