In this paper, an image coding technique that combines irregular subsampling and triangulation is proposed. First, a Delaunay triangulation is constructed over a set of visually significant sampling points selected in...
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(纸本)0780341376
In this paper, an image coding technique that combines irregular subsampling and triangulation is proposed. First, a Delaunay triangulation is constructed over a set of visually significant sampling points selected incrementally as the triangulation progresses. Then a data-dependent triangulation is generated, starting from the Delaunay triangulation, by a series of edge swaps based on the duality of the approximation. Bilinear interpolation is used to approximate the triangular regions. The simulation results show the superiority of the proposed algorithm over JPEG at low bit rates (0.206 bpp and 0.113 bpp) as well as its robustness.
This paper presents an adaptive algorithm for motion compensated color image coding. The algorithm can be used for video teleconferencing or broadcast signals. Activity segmentation is used to reduce the bit rate and ...
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This paper presents an adaptive algorithm for motion compensated color image coding. The algorithm can be used for video teleconferencing or broadcast signals. Activity segmentation is used to reduce the bit rate and a variable stage search is conducted to save computations. The adaptive algorithm is compared with the nonadaptive algorithm and it is shown that with approximately 60 percent savings in computing the motion vector and 33 percent additional compression, the performance of the adaptive algorithm is similar to the nonadaptive algorithm. The adaptive algorithm results also show improvement of up to 1 bit/pel over interframe DPCM coding with nonuniform quantization. The test pictures used for this study were recorded directly from broadcast video in color.
A hardware-oriented image coding processing scheme based on the Haar wavelet transform is presented. The procedure computes a variant of the Haar wavelet transform that uses only addition and subtraction operations, a...
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A hardware-oriented image coding processing scheme based on the Haar wavelet transform is presented. The procedure computes a variant of the Haar wavelet transform that uses only addition and subtraction operations, after that, an optimized methodology performs the selection and coding of the coefficients, tailored for it with the main aim of attaining the lowest circuit complexity hardware implementation. A selection strategy, which does not require the previous ordering of coefficients, has been used. A non-conventional coding methodology, which uses an optimized combination of techniques adapted to the various groups of coefficients, has been devised for the coding of the selected coefficients leading to a compressed representation of the image and reducing the coding problems inherent in threshold selection. The compression level reached for images of 512 x 512 pixels with 256 grey levels is just over 22:1, (0.4 bits/pixel) with a normalized mean square error, nrmse, of 2-3%, with subjective qualities which can be classified as good. The whole compression circuitry has been described and simulated at HDL level for up to 4 consecutive images, obtaining consistent results. The complete processor (excluding memory) for images of 256 x 256 pixels has been implemented using only one general-purpose low-cost FPGA chip, thus proving the design reliability and its relative simplicity. (c) 2006 Elsevier Ltd. All rights reserved.
In this paper, we present a design and implementation of the M-channel linear-phase filter banks with unequal-length and same center of symmetry. The filter banks are separated into paraunitary and biorthogonal case. ...
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In this paper, we present a design and implementation of the M-channel linear-phase filter banks with unequal-length and same center of symmetry. The filter banks are separated into paraunitary and biorthogonal case. We discuss both cases. A novel filter bank can be regarded as a special class of generalized lapped transform with arbitrary number of channels M. In image coding applications, long basis functions should be used to avoid the blocking artifacts in low-frequency bands, while short basis functions should be used to reduce the ringing artifacts in high-frequency bands. Having the same center of symmetry is suitable for progressive image coder [SPIHT] [10]. Filter banks with such characteristics can be achieved structurally by taking acount of the lattice structure. Finally, several design and image coding examples are shown.
The authors propose an embedded wavelet-based image coding algorithm that exploits both the inter- and intra-subband correlations among the wavelet coefficients. The proposed coding algorithm is based on spatial orien...
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The authors propose an embedded wavelet-based image coding algorithm that exploits both the inter- and intra-subband correlations among the wavelet coefficients. The proposed coding algorithm is based on spatial orientation trees (SOT) in which the basic unit is a block of m x n coefficients in contrast to a single coefficient in the set partitioning in hierarchical trees (SPIHT) algorithm. Each SOT has a root node (a block of m x n coefficients) in the LL-subband with the child and descendent blocks in the high frequency subbands. Thus it fuses the features of both block- and tree-based coding algorithms into a single algorithm. Performance of the proposed method is compared (in terms of rate-distortion performance) with the other state-of-the-art coding algorithms including the JPEG2000 for popular test images. Simulation results show that the proposed algorithm has a better coding efficiency over the other coders at very low bit rates. Also, compared with SPIHT it reduces the elements of the auxiliary lists, thereby reducing the memory requirements. In addition, the encoder of the proposed algorithm is significantly faster than that of the SPIHT, but with a slight increase in its decoder complexity.
Analysis/synthesis systems designed for low bit rate image coding, their impact on overall system quality, and their computational complexity are discussed. The investigation focuses on the design of analysis/synthesi...
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Analysis/synthesis systems designed for low bit rate image coding, their impact on overall system quality, and their computational complexity are discussed. The investigation focuses on the design of analysis/synthesis systems for image coding and the perceptual impact of these systems at low bit rates. Two objectives are emphasized in developing these systems: confining the total size of the subband images to be equal to the original image size, and designing the filters so that perceptual distortion is not introduced by the analysis/synthesis system. Methods based on circular convolution and symmetric extensions are developed and discussed in detail. The theory, design, and implementation of both recursive and nonrecursive filtering systems are discussed. Methods are introduced which display advantages over conventional quadrature mirror filter based approaches.< >
A method for designing a vector quantizer by first partitioning the residual image vector space into concentric shells and then searching for the smallest possible codebook to represent the residual image vector space...
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A method for designing a vector quantizer by first partitioning the residual image vector space into concentric shells and then searching for the smallest possible codebook to represent the residual image vector space, while adhering to the visual perceptive qualities such as edges and textures in the image representation, is described. The coding method involves the decomposition of the image vector into relatively independent components, each with a small dynamic range, to permit the design of a small fixed codebook for the vector quantizer. Optimal partitioning amounts to optimally selecting the set of shell radii, which is achieved using a modified form of simulated annealing. The results obtained in the coding of images show that the concentric-shell partition vector quantizer compares favourably with the gain-shape vector quantizer in terms of subjective image quality at the same bit rate while achieving higher SNR and lower computational complexity.
This paper proposes a representative pixel (RP) extraction algorithm and chrominance image recovery algorithm for the colorization-based digital image coding. The colorization-based coding methods reduce the color inf...
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This paper proposes a representative pixel (RP) extraction algorithm and chrominance image recovery algorithm for the colorization-based digital image coding. The colorization-based coding methods reduce the color information of an image and achieve higher compression ratio than JPEG coding;however, they take much more computing time. In order to achieve low computational cost, this paper proposes the algorithm using the set of multiple-resolution images obtained by colorization error minimizing method. This algorithm extracts RPs from each resolution image and colorizes each resolution image utilizing a lower resolution color image, which leads to the reduction of the number of RPs and computing time. Numerical examples show that the proposed algorithm extracts the RPs and recovers the color image fast and effectively.
This paper presents a Fluency image coding System of beef rib-eye images for Beef Marbling Evaluation. This is the second in a series of cooperative researches with the Japan Livestock Technology Association under an ...
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This paper presents a Fluency image coding System of beef rib-eye images for Beef Marbling Evaluation. This is the second in a series of cooperative researches with the Japan Livestock Technology Association under an initiative to construct an Automated Online Beef Marbling Grading Support System by image analysis techniques. Our first cooperative research was on a Beef Marbling Grading Method, and was published in this journal in [Pattern Recognition Lett. 21 (12) (2000) 1037-1050]. This second cooperative research focuses on a binary image coding system that supports remote observation of beef marbling structure from a database of coded beef rib-eye images by users including meat graders, livestock producers, and researchers. image encoding is by a novel automatic contour compression method based on function approximation via interpolation using the Fluency Compactly Supported Sampling Functions of degree 2. image decoding, based on interpolation of the encoded data by the similar functions, enables the web-browser based decoder to reconstruct the original fat contours smoothly even on Affine-transformed enlargement. Experimental results showing, respectively, size and image quality comparisons with other formats that support binary images and several enlargement schemes are included for evaluation. (C) 2002 Elsevier Science B.V. All rights reserved.
Wavelet transform coding (WTC) with vector quantization (VQ) has been shown to be efficient in the application of image compression. An adaptive vector quantization coding scheme with the Gold-Washing dynamic codebook...
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Wavelet transform coding (WTC) with vector quantization (VQ) has been shown to be efficient in the application of image compression. An adaptive vector quantization coding scheme with the Gold-Washing dynamic codebook-refining mechanism in the wavelet domain, called symmetric wavelet transform-based adaptive vector quantization (SWT-GW-AVQ), is proposed for still-image coding in this article. The experimental results show that the GW codebook-refining mechanism working in the wavelet domain rather than the spatial domain is very efficient, and the SVVT-GW-AVQ coding scheme may improve the peak signal-to-noise ratio (PSNR) of the reconstructed images with a lower encoding time. (C) 2002 Wiley Periodicals, Inc.
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