A novel approach to computing egomotion and detecting points not moving rigidly with the scene when an observer moves with unrestricted motion is presented. The approach, using collinear image points, is based on an e...
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ISBN:
(纸本)0818621486
A novel approach to computing egomotion and detecting points not moving rigidly with the scene when an observer moves with unrestricted motion is presented. The approach, using collinear image points, is based on an exact method for cancelling effects of the observer's rotation from optic flow. For each point only the component of velocity normal to the direction of the line joining the collinear points is needed. The algorithm is simple, appears robust, and is ideal for parallel implementation.
A method for identifying groups of intensity edges in an image that are likely to result from the same convex object in a scene is described. A key property of the method is that its output is no more complex than the...
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ISBN:
(纸本)0818621486
A method for identifying groups of intensity edges in an image that are likely to result from the same convex object in a scene is described. A key property of the method is that its output is no more complex than the original image. The method uses a triangulation of linear edge segments to define a local neighborhood that is scale invariant. From this local neighborhood a local convexity graph that encodes which neighboring image edges could be part of a convex group of image edges is constructed. A path in the graph corresponds to a convex polygonal chain in the image, such as a convex polygon or a spiral. Examples are presented to illustrate that the technique finds intuitively salient groups.
A polynomial time algorithm is presented (pruned correspondence search, PCS) with good average case complexity for solving a wide class of geometric maximal matching problems, including the problem of recognizing 3-D ...
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ISBN:
(纸本)0818621486
A polynomial time algorithm is presented (pruned correspondence search, PCS) with good average case complexity for solving a wide class of geometric maximal matching problems, including the problem of recognizing 3-D objects from a single 2-D image. The PCS algorithm is connected with the geometry of the underlying recognition problem only through calls to a verification algorithm. Efficient verification algorithms are given for the case of affine transformations among vector spaces and for the case of rigid 2-D and 3-D transformations with scale. Among the known algorithms that solve the bounded error recognition problem exactly and completely, the PCS algorithm currently has the lowest complexity. Some preliminary experiments suggest that PCS is a practical algorithm.
An early-processing algorithm to extract motion information from closely sampled image sequences is presented. This method outputs dense displacement field, based on the extraction of strips in slices taken from the i...
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ISBN:
(纸本)0818621486
An early-processing algorithm to extract motion information from closely sampled image sequences is presented. This method outputs dense displacement field, based on the extraction of strips in slices taken from the image volume along the temporal dimension. The extracted strips provide estimates of the velocity component along the slice orientation. Because of the high sampling rate, the motion is assumed to be piecewisely translational. A voting scheme to estimate the position of FOE while extracting strips is proposed. The true velocity can then be calculated. Results on several real image sequences and a promising speedup from the parallel implementation on the connection machine are presented.
An edge detection algorithm based on the regularization theory in which the smoothness is controlled spatially over the image space is presented. The algorithm starts with an oversmoothed regularized solution and iter...
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ISBN:
(纸本)0818621486
An edge detection algorithm based on the regularization theory in which the smoothness is controlled spatially over the image space is presented. The algorithm starts with an oversmoothed regularized solution and iteratively refines the surface around discontinuities using the knowledge on the structure of discontinuities exhibited in the error signal between the image data and the previous regularized solution. The spatial control of smoothness is shown to resolve the conflict between detection and localization criteria. The adaptive nature of the algorithm eliminates the need to select image-dependent parameters and enables the extraction of multiscale features from the image. The computational aspects of the algorithm as well as its performance on real and synthetic images are considered.
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.
An approach for determining the location and orientation of a camera mounted on an ALV (autonomous land vehicle) is proposed. The authors choose the road boundaries and the objects with vertical edges to be the calibr...
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ISBN:
(纸本)0818621486
An approach for determining the location and orientation of a camera mounted on an ALV (autonomous land vehicle) is proposed. The authors choose the road boundaries and the objects with vertical edges to be the calibration objects. During the calibration process, the ALV is supposed to move with pure translation. The camera models are derived by using two or three images under the assumptions that the height of the camera and the distance during taking images are known in advance. The tilt and swing angles can be computed from the first image. The pan angle can then be derived by using the projections of vertical edges in three images. If the angle between the moving direction of the ALV and the direction of road boundaries is large enough, two images are enough to find the pan angle. Two translational parameters can be found by employing the projections of vertical edges in two or three images.
A fuzzy adaptive distance dynamic clusters (FADDC) algorithm, which is specially designed to search for clusters that lie in subspaces (such as lines, and (hyper)planes) is presented. One major drawback of all cluster...
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ISBN:
(纸本)0818621486
A fuzzy adaptive distance dynamic clusters (FADDC) algorithm, which is specially designed to search for clusters that lie in subspaces (such as lines, and (hyper)planes) is presented. One major drawback of all clustering algorithms is that the number of clusters has to be known a priori. A novel compatible cluster merging (CCM) technique, which finds the optimum number of clusters in an efficient way, is proposed. Such subspace clustering techniques may be used for character recognition and to obtain straight-line descriptions of an edge image. They may also be used to obtain planar approximations of 3-D (range) data. The effectiveness of the proposed algorithms in several such situations is demonstrated with real data.
A method is presented for efficiently maintaining and searching a database of three-dimensional models so they can be reliably recognized from arbitrary two-dimensional projections in the presence of noise and occlusi...
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ISBN:
(纸本)0818621486
A method is presented for efficiently maintaining and searching a database of three-dimensional models so they can be reliably recognized from arbitrary two-dimensional projections in the presence of noise and occlusion. The core of the process is the topologically defined network of invariants which breaks three-dimensional models down into small, local groups of features and indexes these groups using functions that are invariant under translation, rotation, scaling, and orthographic projection. The network encodes the geometrical relationships between these groups so that grouping information can be used to increase the speed of matching.
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.
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