Many biological objects are elongated. This research addresses the issue of recognizing elongated objects from both 2D intensity images and 3D volumes. A mathematical model, called tube model, is developed for this cl...
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The dual irregular pyramid combines the advantage of adaptivity with a limited computational complexity of neighborhood operations. The levels of the pyramid, dual graphs, are defined only if (hey are planar. We prove...
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The method described here for reconstructing the shape of Lambertain surfaces from the shading information inherent in a monocular image can deal with the surface whose image,a smooth and non-self occluding one,is pro...
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ISBN:
(纸本)0780312333
The method described here for reconstructing the shape of Lambertain surfaces from the shading information inherent in a monocular image can deal with the surface whose image,a smooth and non-self occluding one,is produced by orthographic projection and parallel light source from a known *** dividing the image area into serial triangles,the intensity function I(x,y) on each triangle can be *** the help of a support function and a transformation,it is proved that each triangle represents a cylinder in a new(X-Y) coordinates with (s,t) as its components of the surface ***,the ill-posed image brightness constraint equation in cartesian coordinates can be solved in(X-Y) coordinates with only one variable(s or t).It is necessary to find out,firstly,the pixel which has the maximal intensity,the assigning of its depth leads to the direct recovery of the shape at each point without the necessity of integration.
In order to usefully apply the concept of the curve pyramid on grouping problems, the shift variance problem must be overcome by extending the concept to irregular pyramids. These have a structure that adapts to the i...
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In order to usefully apply the concept of the curve pyramid on grouping problems, the shift variance problem must be overcome by extending the concept to irregular pyramids. These have a structure that adapts to the image data by deriving control information from curve relations. The algorithm that builds the irregular curve pyramid by deriving higher levels of abstraction from a set of relations goes far beyond merely solving the shift variance problem. It can reduce the computational complexity in comparable applications where all possible combinations of parts have to be checked in order to reassemble complex objects.< >
A Hopfield neural network approach to blind bilevel image restoration is presented. In the approach, two kinds of Hopfield neural networks are used. One is the analog Hopfield neural network, utilized to estimate the ...
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A Hopfield neural network approach to blind bilevel image restoration is presented. In the approach, two kinds of Hopfield neural networks are used. One is the analog Hopfield neural network, utilized to estimate the parameters of the finite point spread function (PSF) of a blurring system. The other one is the modified Hopfield neural network used to restore bilevel image. The entire model is based on the alternative operation of the two networks. In the modified Hopfield neural network, the eliminating highest error (EHE) criterion is applied for the purpose of obtaining a more precise solution. Simulation results show that, after a few iterations, the model always obtains a bilevel image whose quality is almost the same as, or even better than, what is obtained by the modified Hopfield network when the precise parameters of PSF are used. The results are quite good. If the EHF criterion is not used, the model does not achieve a good bi-level image.< >
An important step in the analysis of printed documents is the segmentation and classification of blocks into categories such as photographs, titles, paragraphs, etc. The authors present an approach to enhance and comb...
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An important step in the analysis of printed documents is the segmentation and classification of blocks into categories such as photographs, titles, paragraphs, etc. The authors present an approach to enhance and combine two commonly used methods, a merging bottom-up approach and a cutting top down approach, to segment pages of a newspaper. The implementation of a layout analysis system as a preprocessing module for a commercial product is described.< >
The problem of egomotion recovery has been treated by using as input local image motion, with the published algorithms utilizing the geometric constraint relating 2-D local image motion (optical flow, correspondence, ...
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The issue of recognizing 3D elongated objects from 2D intensity images is addressed. A tube model, locally similar to generalized cones, is developed for the class of elongated objects. A recognition strategy that com...
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The issue of recognizing 3D elongated objects from 2D intensity images is addressed. A tube model, locally similar to generalized cones, is developed for the class of elongated objects. A recognition strategy that combines 2D contour properties and surface shading information is used to exploit the power of the 3D model. Reliable contours provide constraints for localizing the objects of interest. The theory of optimal filters is adopted in verifying the shading of hypothesized objects. Object recognition is achieved through optimizing the signal-to-noise response with respect to model parameters. A sweeping operation is proposed as a further stage of identifying objects so that the overall performance of the system does not heavily rely on the quality of local feature detection.< >
The problem of egomotion recovery has been treated by using as input local image motion, with the published algorithms utilizing the geometric constraint relating 2-D local image motion (optical flow, correspondence, ...
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The problem of egomotion recovery has been treated by using as input local image motion, with the published algorithms utilizing the geometric constraint relating 2-D local image motion (optical flow, correspondence, derivatives of the image flow) to 3-D motion and structure. Since it has proved very difficult to achieve accurate input (local image motion), a lot of effort has been devoted to the development of robust techniques. A new approach to the problem of egomotion estimation is taken, based on constraints of a global nature. It is proved that local normal flow measurements form global patterns in the image plane. The position of these patterns is related to the three dimensional motion parameters. By locating some of these patterns, which depend only on subsets of the motion parameters, through a simple search technique, the 3-D motion parameters can be found. The proposed algorithmic procedure is very robust, since it is not affected by small perturbations in the normal flow measurements. As a matter of fact, since only the sign of the normal flow measurement is employed, the direction of translation and the axis of rotation can be estimated with up to 100% error in the image measurements.< >
There is a considerable interest in designing automatic systems that will scan a given paper document and store it on electronic media for easier storage, manipulation, and access. Most documents contain graphics and ...
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