A local parallel method is described for computing the stochastic completion field introduced in an earlier report. The local parallel method can be interpreted as a stable finite difference scheme for solving the und...
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ISBN:
(纸本)0818672587
A local parallel method is described for computing the stochastic completion field introduced in an earlier report. The local parallel method can be interpreted as a stable finite difference scheme for solving the underlying Fokker-Planck equation identified by Mumford. The new method is more plausible as a neural model since (1) unlike the previous method, it can be computed in a sparse, locally connected network;and (2) the network dynamics are consistent with psycophysical measurements of the time course of illusory contour formation.
Building integrated models of existing 3-D objects is a key requirement for both reverse engineering and object recognition systems. An automatic 3-D model builder goes through three main steps: i) surface sampling fr...
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ISBN:
(纸本)0818658258
Building integrated models of existing 3-D objects is a key requirement for both reverse engineering and object recognition systems. An automatic 3-D model builder goes through three main steps: i) surface sampling from many views, ii) registration of the sampled views, and iii) integration of the registered views. The accuracy obtained depends on the acquisition and registration errors. The latter is critical since a misalignment of the range views causes their noise distributions to be centered around different means, which makes it difficult to reduce the effect of the acquisition error by simple averaging. In this paper, we propose a general algorithm that reduce significantly the level of the registration errors between all pairs in a set of range views. This algorithm refines initial estimates of the transformation matrices obtained from the calibrated acquisition setup. It considers the network of views as a whole and minimizes the registration errors of all views simultaneously. This leads to a well-balanced network of views in which the registration errors are equally distributed. Experimental results show an improvement of both the calibrated registrations and integrated models.
We propose a computational model motivated by human cognitive processes for detecting changes of driving environments. The model, call dynamic visual model, consists of three major components: sensory, perceptual, and...
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ISBN:
(纸本)0769519008
We propose a computational model motivated by human cognitive processes for detecting changes of driving environments. The model, call dynamic visual model, consists of three major components: sensory, perceptual, and conceptual components.. The proposed model is used as the underlying framework in which a system for detecting and recognizing road signs is developed.
It is often necessary to handle randomness and geometry is computervision, for instance to match and fuse together noisy geometric features such as points, lines or 3D frames, or to estimate a geometric transformatio...
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ISBN:
(纸本)0818672587
It is often necessary to handle randomness and geometry is computervision, for instance to match and fuse together noisy geometric features such as points, lines or 3D frames, or to estimate a geometric transformation from a set of matched features. However, the proper handling of these geometric features is far more difficult than for points, and a number of paradoxes can arise. We analyse in this article three basic problems: (1) what is a uniform random distribution of features, (2) how to define a distance between features, and (3) what is the 'mean feature' of a number of feature measurements, and we propose generic methods to solve them.
We address the problem of constructing a complete surface model of an object using a set of registered range images. Our approach is based on a dynamic balloon model represented by using a triangulated mesh. The verti...
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ISBN:
(纸本)0818658258
We address the problem of constructing a complete surface model of an object using a set of registered range images. Our approach is based on a dynamic balloon model represented by using a triangulated mesh. The vertices in the mesh are linked to their neighboring vertices through springs to simulate the surface tension and to keep the shell smooth. Unlike other dynamic models proposed by previous researchers, our balloon model is purely driven by an applied inflation force towards the object surface from inside of the object, until the mesh elements reach the object surface. The system includes an adaptive local triangle mesh subdivision scheme that results in an evenly distributed mesh. Since our approach is not based on global minimization, it can handle complex, non-star-shaped objects without relying on a carefully selected initial state or encountering local minimum problem. It also allows us to adapt the mesh surface to changes in local surface shapes and to handle holes present in the input data through adjusting certain system parameters adaptively and locally. We present results on some complex, nonstar-shaped objects from real range images.
The demo presents a virtual min-or interface which reacts to the viewer using robust, real-time face tracking. The display directly combines a user's face with various graphical distortions, performed only on the ...
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ISBN:
(纸本)0818684976
The demo presents a virtual min-or interface which reacts to the viewer using robust, real-time face tracking. The display directly combines a user's face with various graphical distortions, performed only on the face region in the image. The face detection and tracking is done in real-time, so the graphical effect stays with the user and continues to adapt as they move within the viewing space, increasing in intensity as the user approaches the display.
A demonstration of a software prototype, called VADIS, (Video Analysis, Display and Indexing System) is presented. The functionality of VADIS includes real-time indexing of incoming live video stream using color histo...
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ISBN:
(纸本)0818684976
A demonstration of a software prototype, called VADIS, (Video Analysis, Display and Indexing System) is presented. The functionality of VADIS includes real-time indexing of incoming live video stream using color histogram based frame differencing, non-real-time cut detection and indexing of Motion JPEG or MPEG-1 video files. It includes a feature to save the indices and the storyboard generated during the indexing process.
The Perseus system is a purposive visual architecture that has been used to recognize the pointing gesture. recognition of this gesture is an important part of natural human-machine interfaces. Perseus is modularized ...
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ISBN:
(纸本)0818672587
The Perseus system is a purposive visual architecture that has been used to recognize the pointing gesture. recognition of this gesture is an important part of natural human-machine interfaces. Perseus is modularized into 6 types of components: feature maps, object representations, markers, visual routines, a segmentation map, and a long term visual memory. This structure not only allows Perseus to use knowledge about the task and environment at every stage of processing to more efficiently and accurately solve the pointing task, but also allows it to be extended to tasks other than recognizing pointing.
We introduce in this paper two probabilistic reasoning models (PRM-I and PRM-2) which combine the Principal Component Analysis (PCA) technique and the Bayes classifier and show their feasibility on the face recognitio...
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ISBN:
(纸本)0818684976
We introduce in this paper two probabilistic reasoning models (PRM-I and PRM-2) which combine the Principal Component Analysis (PCA) technique and the Bayes classifier and show their feasibility on the face recognition problem. The conditional probability density function for each class is modeled using the within class scatter and the Maximum A Posteriori (MAP) classification rule is implemented in the reduced PCA subspace. Experiments carried out using 1107 facial images corresponding to 369 subjects (with 169 subjects having duplicate images) from the FERET database show that the PRM approach compares favorably against the two well-known methods for face recognition the Eigenfaces and Fisherfaces.
This paper addresses the problem of estimating the epipolar geometry from point correspondences between two images taken by uncalibrated perspective cameras. It is shown that Jepson's and Heeger's linear subsp...
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ISBN:
(纸本)0818672587
This paper addresses the problem of estimating the epipolar geometry from point correspondences between two images taken by uncalibrated perspective cameras. It is shown that Jepson's and Heeger's linear subspace technique for infinitesimal motion estimation can be generalized to the finite motion case by choosing an appropriate basis for projective space. This yields a linear method for weak calibration. The proposed algorithm has been implemented and tested on both real and synthetic images, and it is compared to other linear and non-linear approaches to weak calibration.
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