In this paper, we present an analog VLSI spatio-frequency analysis based visual feature extraction retina, dedicated to the real-time stereo vision. In this retina, local extreme points in the DoG filtered image are e...
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In this paper, we present an analog VLSI spatio-frequency analysis based visual feature extraction retina, dedicated to the real-time stereo vision. In this retina, local extreme points in the DoG filtered image are extracted as pertinent visual features. A 128-pixel line-based prototype chip is presented with experiment results. A processing speed of 100k lines/s has been obtained (exposition time excluded), it will be used in an integrated analog stereo vision system for real-time obstacle detection task.
This paper presents a VLSI implementation of discrete wavelet transform (DWT). The architecture is systolic in nature and performs both high-pass and low-pass coefficient calculations with only one set of multipliers,...
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This paper presents a VLSI implementation of discrete wavelet transform (DWT). The architecture is systolic in nature and performs both high-pass and low-pass coefficient calculations with only one set of multipliers, in contrast to the approaches presented in the literature. The architecture is simple, modular, and cascadable, and has been implemented in VLSI. Experimental results show that real-time coefficient calculation on a 512/spl times/512 monochrome video input can be achieved with 1.2 /spl mu/m technology.
The task of image coding is to improve the efficiency of visual communication channels. This entails minimizing the amount of data required to transmit the information about the radiance field. We assess this task in ...
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ISBN:
(纸本)081941543X
The task of image coding is to improve the efficiency of visual communication channels. This entails minimizing the amount of data required to transmit the information about the radiance field. We assess this task in the context of visual communication channel design including image gathering, coding, and Wiener restoration which results in channel designs with significantly improved performance. Conventional assessments are limited to the digital transmission channel beginning at the output of the image-gathering device and ending at the input to the image-display device. Our end-to-end assessment, in addition, incorporates these two devices. This assessment combines Shannon's communication theory with Wiener's restoration filter and with the critical design factors of the image gathering and display devices. This provides the metrics needed to quantify and optimize the end-to-end performance of the visual communication channel. The results are described.
The guiding principle of this study is to find an optimum way to simplify the contours produced by a second generation coding scheme based on morphological segmentation. For this purpose, evaluations of existing metho...
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ISBN:
(纸本)081941638X
The guiding principle of this study is to find an optimum way to simplify the contours produced by a second generation coding scheme based on morphological segmentation. For this purpose, evaluations of existing methods for contour simplification are carried out first. Based on the human visual phenomenon, a new nonlinear filter by means of majority operation is designed to simplify the contours in order to obtain an optimum compromise between the cost for contour coding and visual quality. Applications for region-based still image coding and video coding are demonstrated. Experimental results have shown an average of 20% reduction of bits for contour coding while keeping good visual quality.
visual communication can be regarded as efficient only if the amount of information that it conveys from the scene to the observer approaches the maximum possible and the associated cost approaches the minimum possibl...
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ISBN:
(纸本)081941543X
visual communication can be regarded as efficient only if the amount of information that it conveys from the scene to the observer approaches the maximum possible and the associated cost approaches the minimum possible. To deal with this problem, Fales and Huck have integrated the critical limiting factors that constrain image gathering into classical concepts of communication theory. This paper uses this approach to assess the electro-optical design of the image gathering device. Design variables include the f-number and apodization of the objective lens, the aperture size and sampling geometry of the photodetection mechanism, and lateral inhibition and nonlinear radiance-to-signal conversion akin to the retinal processing in the human eye. It is an agreeable consequence of this approach that the image gathering device that is designed along the guidelines developed from communication theory behaves very much like the human eye. The performance approaches the maximum possible in terms of the information content of the acquired data, and thereby, the fidelity, sharpness and clarity with which fine detail can be restored, the efficiency with which the visual information can be transmitted in the form of decorrelated data, and the robustness of these two attributes to the temporal and spatial variations in scene illumination.
This paper describes the methodology of fractal coding and some new fractal compression results for gray scale images. image compression is discussed from a systems point of view. Current measures of compression perfo...
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ISBN:
(纸本)081941543X
This paper describes the methodology of fractal coding and some new fractal compression results for gray scale images. image compression is discussed from a systems point of view. Current measures of compression performance are not necessarily correlated with image system performance measures. For example, at a fixed `quality' level, bits/pixel type measures are correlated to transmission times for sending a single image under ideal conditions. However, such measures don't necessarily indicate interaction effects between image coding and systems issues such as communication channel errors and communication channel loading. It is proposed that a systems performance measure of image coding techniques be developed.
This paper describes an image modeling scheme based on wavelet signal decomposition and statistical texture analysis, and its application in model-based image coding. In this approach, the image being considered is fi...
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ISBN:
(纸本)081941638X
This paper describes an image modeling scheme based on wavelet signal decomposition and statistical texture analysis, and its application in model-based image coding. In this approach, the image being considered is first decomposed into octal signal bands which contains different spectral components of the images. Based on the property of the signal decomposition statistical texture analysis techniques are hierarchically employed to separate the image into different categories with distinct modeling parameters. Coding is performed based on the texture image model.
Biorthogonal wavelets or filterbanks are shown to be superior in coding gain performance than orthogonal ones for logarithmic subband decompositions (limited to iterative decomposition of the downsampled output of the...
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ISBN:
(纸本)081941638X
Biorthogonal wavelets or filterbanks are shown to be superior in coding gain performance than orthogonal ones for logarithmic subband decompositions (limited to iterative decomposition of the downsampled output of the analysis low-pass filter). As a consequence, for logarithmic decompositions, the optimal filter is not an ideal filter. This is shown for maximally regular biorthogonal and orthogonal filters, as well as filters designed to optimize the subband coding grain.
A lossy image compression technique, incorporating least squares cubic spline pyramids, vector quantization, predictive coding and arithmetic coding was developed for the compression and reconstruction of Magnetic Res...
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ISBN:
(纸本)081941638X
A lossy image compression technique, incorporating least squares cubic spline pyramids, vector quantization, predictive coding and arithmetic coding was developed for the compression and reconstruction of Magnetic Resonance images. Typical results of 29.76 dB Peak Signal-to-Noise ratio (PSNR) for 0.45 bits per pixel (bpp) compression, and 27.91 dB PSNR for 0.33 bpp, compare very favorably with other, recently reported, medical image compression results. Furthermore, block artifacts are absent from the recovered pictures.
A new scheme based on priori face knowledge and shift template method for fast face feature points extraction are presented in this paper. A fairly good accuracy and speed in detecting the feature points of eyebrows, ...
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ISBN:
(纸本)081941638X
A new scheme based on priori face knowledge and shift template method for fast face feature points extraction are presented in this paper. A fairly good accuracy and speed in detecting the feature points of eyebrows, eyes, nose and mouth have been achieved by a pair of complementary templates. It is shown by computer simulation that the scheme is very suitable for very low bit rate model-based image coding in real time applications.
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