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Reduction of ringing noise in transform image coding using simple adaptive filter

ELECTRONICS LETTERS 1998年第22期34卷 2110-2112页

作者： Kaup, A Siemens AG D-81730 Munich Germany

A numerically simple filter fcr reducing ringing noise in transform coded images is proposed. The filter adapts to the local image characteristics and has been specifically designed to amend the current deblocking fil... 详细信息

关键词： telecommunication standards transform coding Image and video coding ringing noise transform image coding Filtering methods in signal processing objective image quality adaptive filter adaptive filters Codes Video signal processing current deblocking filter Signal processing theory local image characteristics video coding subjective image quality block codes

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A comparison of vector quantization subband and transform coding of imagery

A comparison of vector quantization subband and transform co...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： T.R. Fischer M.E. Blain Department of Electrical and Computer Engineering Washington State University Pullman WA USA Department of Electrical Engineering Texas A and M University College Station TX USA

transform image coding using scalar quantization, pyramid vector quantization (PVQ), and generalized Lloyd algorithm vector quantization (VQ) and subband image coding using scalar quantization and pyramid vector quantization are considered. In a simulation study at low bit rates (0.5 bit/pel) the transform VQ coder generally provided the largest peak-signal-to-noise ratio (PSNR), although the PVQ subband coder was superior for some images. At larger encoding rates (for which, because of complexity, the generalized Lloyd algorithm VQ was not considered) the scalar-quantizer subband coder generally yielded larger PSNR than did the scalar-quantizer transform coder. The PVQ transform and subband coders provided similar values of PSNR, but the subband coded image had less blockiness than the transform-coded image.< >

关键词： Vector quantization transform coding Image coding Encoding PSNR Bit rate Statistics Filters Discrete transforms Discrete cosine transforms

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Scalable HDTV coding with motion-compensated subband and transform coding

Scalable HDTV coding with motion-compensated subband and tra...

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IEEE Conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： Liangchi Hsu K.R. Rao Global Paging Infrastructure Division Motorola Inc. Fort Worth TX USA Electrical Engineering Department University of Texas Arlington Arlington TX USA

We propose a scalable multiresolution coding scheme for HDTV using hybrid motion compensated subband and transform coding. The scheme exploits advantages of discrete wavelet transforms, hierarchical multiresolution motion compensation, and transform coding. Three resolutions for applications of HDTV, conventional TV, and videophone, are aimed. Optimal bit allocation is performed for each resolution, where the constrained bitrate is required. An MPEG-like coding method with the DCT or lapped orthorgonal transform (LOT) is applied to the lowest subband. A motion-compensated PCM scheme and an efficient but low complexity VWL coding are applied to the medium and full resolutions. The performance of DCT and LOT in these applications is compared. Simulation results show that very good subjective and objective quality can be achieved for all the three resolutions.

关键词： HDTV transform coding Bit rate Discrete cosine transforms Spatial resolution Motion compensation Video coding Streaming media Decoding Videoconference

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Near lossless transform coding of multispectral images

Near lossless transform coding of multispectral images

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： A.G. Tescher J.T. Reagan J.A. Saghri Palo Alto Advanced Technology Center Lockheed Martin Corporation Palo Alto CA USA

The authors have extended the previously developed adaptive transform coding based multispectral algorithm for the lossless/virtually lossless case. Preliminary results are encouraging compared with traditional lossless implementation. The primary technical challenge is to compensate for the quantization errors introduced in processing the high dynamic range eigen images.

关键词： transform coding Multispectral imaging Image coding Quantization Performance loss Algorithm design and analysis Adaptive systems Decorrelation Redundancy Dynamic range

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Fast interframe transform coding based on characteristics of transform coefficients and frame difference

Fast interframe transform coding based on characteristics of...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Yui-Lam Chan Wan-Chi Siu Department of Electronic Engineering Hong Kong Polytechnic University Hong Kong China

The interframe transform coding has been seldom used in practice because of the considerable computational complexity. To reduce the computational complexity, a fast algorithm is proposed which reduces the number of operations by limiting the calculation of transform coefficients without significant quality degradation. Different modes of transformation are performed according to frame difference. This proposed fast interframe coding, like the MPEG, has an asymmetric property with decoding being much faster than encoding. Computer simulations show that this fast algorithm can significantly reduce the computational burden in interframe transform coding and is even faster than MPEG-like coding.

关键词： transform coding Computational complexity Discrete cosine transforms Discrete transforms Degradation Decoding Computer simulation Frequency Image sequences Pixel

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Luby transform coding Aided Iterative Detection for Downlink SDMA Systems

Luby Transform Coding Aided Iterative Detection for Downlink...

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IEEE Workshop on Signal Processing Systems (SIPS)

作者： C. Y. Wei T. D. Nguyen N. Wu J. Akhtman L.L. Yang L. Hanzo School of ECS University of Southampton UK

A Luby transform (LT) coded downlink Spatial Division Multiple Access (SDMA) system using iterative detection is proposed, which invokes a low-complexity near-Maximum-Likelihood (ML) Sphere Decoder (SD). The Ethernet-based Internet section of the transmission chain inflicts random packet erasures, which is modelled by the Binary Erasure Channel (BE), while the wireless downlink imposes both fading and noise. A novel Log-Likelihood Ratio based packet reliability meric is used for identifying the channel-decoded packets, which are likely to be error-infested. Packets having residual errors must not be passed on to the LT decoder for the sake of avoiding LT-decoding-induced error propagation. The proposed scheme is capable of maintaining an infinitesimally low packet error ratio in the downlink of the wireless Internet for E b /N 0 values in excess of about 3dB.

关键词： transform coding Downlink Multiaccess communication Decoding Internet Transmitters Convolutional codes MIMO Throughput Convolution

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A new adaptive classified transform coding method (image coding)

A new adaptive classified transform coding method (image cod...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Wen-Jun Zhang Song-Yu Yu Hong-Bin Chen Institute of Image Processing & Pattern Recognition Shanghai Jiaotong University Shanghai China

An efficient discrete cosine transform technique using a new adaptive feature for bandwidth compression is described. Taking account of human visual characteristics and transform coefficient statistics, the higher activity region is further classified into four subclasses according to four proposed basic patterns, while the lower activity region is assigned to four subclasses according to its AC-energy (image activity) distribution. Computer simulations shows that the proposed adaptive coder exhibits a performance improvement of 1 dB or more over conventional adaptive coders at the same coding rates.< >

关键词： transform coding Image coding Humans Discrete transforms Image reconstruction Degradation Bandwidth Bit rate Image storage Discrete cosine transforms

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A comparison of flat and object-based transform coding techniques for the compression of multispectral images

A comparison of flat and object-based transform coding techn...

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IEEE International Conference on Image Processing

作者： M. Cagnazzo G. Poggi L. Verdoliva Dipartimento di Ingegneria Elettronica e Telecomunicazioni Università di Napoli Federico II Napoli Italy

In this work we implement and compare several state-of-the-art transform coding schemes for the compression of multispectral images, in order to better understand which elements have a deeper impact on the overall performance, and which tools guarantee the best results. All schemes are based on Karhunen-Loeve transform and/or wavelet transform, in various combinations, and use SPIHT as the coding engine. Moreover, besides the ordinary techniques, their object-based counterparts are also examined, so as to study the viability of such approach [M. Cagnazzo et al., Oct 2004] for these images. Whenever possible, an optimal rate allocation strategy is applied. The experiments, performed on images acquired by two different sensors, highlight the superiority of KLT as spectral transform; the rough equivalence between object-based and ordinary techniques in terms of rate-distortion performance; and the importance of the optimal allocation.

关键词： transform coding Image coding Multispectral imaging Discrete wavelet transforms Karhunen-Loeve transforms Image segmentation Wavelet transforms Engines Rate-distortion Discrete transforms

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Optimal dimension reduction and transform coding with mixture principal components

Optimal dimension reduction and transform coding with mixtur...

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International Joint Conference on Neural Networks (IJCNN)

作者： C. Archer T.K. Leen Department of Computer Science and Engineering Oregon Graduate Institute of Science and Technology Beaverton OR USA

The paper addresses the problem of resource allocation in local linear models for nonlinear principal component analysis (PCA). In the local PCA model, the data space is partitioned into regions and PCA is performed in each region. Our primary result indicates that the advantage of these models over conventional PCA has been significantly underestimated in previous work. We apply local PCA models to the problems of image dimension reduction and transform coding. Our results show that by allocating representation or coding resources to the different image regions, instead of using a fixed arbitrary dimension everywhere, substantial increases in dimension reduced or compressed image qualify can be achieved.

关键词： transform coding Principal component analysis Resource management Nonlinear distortion Space technology Image coding Bit rate Computer science Solid modeling Search methods

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An adaptive variable block size DCT transform coding system

An adaptive variable block size DCT transform coding system

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China International Conference on Circuits and Systems

作者： Chun-tat See Wai-kuen Cham Department of Electronic Engineering Chinese University of Hong Kong Hong Kong China

Variable block size (VBS) transform coding technique has been proven to be capable of enhancing performance of a fixed size transform coding system. However, the criterion of determining the block size used still remains to be devised. In this paper, an edge discriminator (ED) criterion is proposed to determine the block size suitable for a particular area of an image. Comparison has been made with Chen's system by using mean square error (MSE) as criterion. It is shown that the variable block size DCT transform system using proposed decision criterion has better MSE performance for all bit rates tested.< >

关键词： Discrete cosine transforms transform coding Bit rate Statistics Image coding Image segmentation Mean square error methods Decoding Adaptive systems System testing

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