This paper aims at proposing an elastically deformable surface with use of differential geometric structures. On the basis of the Theory of a Cosserat Surface, a computationally processable equation that relates the a...
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ISBN:
(纸本)0769522270
This paper aims at proposing an elastically deformable surface with use of differential geometric structures. On the basis of the Theory of a Cosserat Surface, a computationally processable equation that relates the accumulated elastic energy and the variations in the differential geometry variables (metric and curvature tensors) of the deformable surface is presented On the basis of our analysis, we propose a novel algorithm to compute more precisely, without compromising the interface's simplicity, the potential deformation energy in terms of the derivatives of the surface. With our proposal, we may maintain the finite difference scheme for computing deformations iteratively. Some simulation results are included.
This paper presents a new approach to image restoration based on ANN, considering the learning of the inverse process using a standard image for training under a multiscale approach. Different models of ANN were teste...
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In this work, we introduce a new scheme to extract hierarchical isocontours from regular and irregular 2D sampled data and to encode it at single rate or progressively. A dynamic tessellation is used to represent and ...
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ISBN:
(纸本)0769522270
In this work, we introduce a new scheme to extract hierarchical isocontours from regular and irregular 2D sampled data and to encode it at single rate or progressively. A dynamic tessellation is used to represent and adapt the 2D data to the isocontour This adaptation induces a controlled multi-resolution representation of the isocontour We can then encode this representation and control the geometry and topology of the decoded isocontour The resulting algorithms form an efficient and flexible isocontour extraction and compression scheme.
Many applications of geometry processing andcomputer vision relies on geometric properties of curves, particularly their curvature. Several methods have been proposed to estimate the curvature of a planar curve, most...
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ISBN:
(纸本)0769522270
Many applications of geometry processing andcomputer vision relies on geometric properties of curves, particularly their curvature. Several methods have been proposed to estimate the curvature of a planar curve, most of them for curves in digital spaces. This work proposes a new method for curvature estimation based on weighted least square fitting and local arc-length approximation. Convergence analysis of this method and noise impact on the estimator accuracy are given. Numerical robustness issues are addressed with practical solutions. The implementation of the method is compared to other curvature estimation methods.
This paper suggests an hierarchical region based representation to implement detection of shapes in gray-scale images. The Max-Tree structure has demonstrated to be useful for this purpose, offering a semantic objects...
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ISBN:
(纸本)0769522270
This paper suggests an hierarchical region based representation to implement detection of shapes in gray-scale images. The Max-Tree structure has demonstrated to be useful for this purpose, offering a semantic objects vision of the image, therefore, reducing the number of elements to process in relation to the pixel based representation. In this way, a particular thresholding information, associated with a specific shape analysis, can be used to determine the segmentation or filtering of regions of interest with lesser computational effort. For to demonstrate this technique, a generic application of detection of lines is proposed using the distance transform approach on each connected component from the depth searching in the mentioned tree.
This paper describes the development of a vision-based, nighttime navigation support system for automotive vehicles driving in semi-structured environments. The focus is on automatic reduction of glare produced by hig...
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ISBN:
(纸本)0769522270
This paper describes the development of a vision-based, nighttime navigation support system for automotive vehicles driving in semi-structured environments. The focus is on automatic reduction of glare produced by high beams from incoming vehicles and on generation of virtual lanes that are overlaid on the image where actual road markings should exist. To accomplish these goals, we develop video-based robust techniques that produce enhanced road images in real-time. The proposed techniques are validated by experiments with real video streams, which demonstrates the system's performance and accuracy under real conditions.
Active contours approach is a very used family of techniques in image analysis. This work presents a comparative study between two active contour approaches for image segmentation. Level sets method and deformable con...
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ISBN:
(纸本)0769522270
Active contours approach is a very used family of techniques in image analysis. This work presents a comparative study between two active contour approaches for image segmentation. Level sets method and deformable contours under B-spline representation are compared These image segmentation methods have different features and are difficult to compare in terms of performance, accuracy and initialization conditions. Both are implemented and a way to calculate the approximation error is developed As a conclusion of this work a theoretical comparison and a comparative characterization of the approximation error for each method are presented.
In this work we model the problem of identifying how close structurally two proteins are as a problem of measuring the similarity between color images that represent their contact maps, where the chromatic information...
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ISBN:
(纸本)0769522270
In this work we model the problem of identifying how close structurally two proteins are as a problem of measuring the similarity between color images that represent their contact maps, where the chromatic information encodes the chemical nature of the contacts. We study two conceptually distinct methods to measure the similarity between such contact maps: a content-based image retrieval one and another based on image registration. In experiments with contact maps constructed from the PDB, the image registration approach was able to identify with 100% precision 8 instances of a protein class mixed with 28 proteins of other classes. The content-based image retrieval approach had an accuracy only a little worse than that.
In this paper we address the problem of lane detection and lane tracking. A linear model is used to approximate lane boundaries in the first frame of a video sequence, using a combination of the edge distribution func...
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ISBN:
(纸本)0769522270
In this paper we address the problem of lane detection and lane tracking. A linear model is used to approximate lane boundaries in the first frame of a video sequence, using a combination of the edge distribution function and the Hough Transform. A new linear-parabolic model is used in the subsequent frames: the linear part of the model is used to fit the near vision field, while the parabolic model fits the far field. The proposed technique demands low computational power and memory requirements, and showed to be robust in the presence of noise, shadows, lack of lane painting and change of illumination conditions.
Topologically adaptable snakes, or simply T-snakes, are a standard tool for automatically identifying multiple segments in an image. This work introduces a novel approach for controlling the topology of a T-snake. It ...
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ISBN:
(纸本)0769522270
Topologically adaptable snakes, or simply T-snakes, are a standard tool for automatically identifying multiple segments in an image. This work introduces a novel approach for controlling the topology of a T-snake. It focuses on the loops formed by the so-called projected curve which is obtained at every stage of the snake evolution. The idea is to make that curve the image of a piecewise linear mapping of an adequate class. Then, with the help of an additional structure-the Loop-Tree-it is possible to decide in O(1) time whether the region enclosed by each loop has already been explored by the snake. This makes it possible to construct an enhanced algorithm for evolving T-snakes whose performance is assessed by means of statistics and examples.
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