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.
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.
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.
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 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.
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