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FIXED AND ADAPTIVE PREDICTORS FOR HYBRID PREDICTIVE transform coding

IEEE TRANSACTIONS ON COMMUNICATIONS 1985年第12期33卷 1291-1302页

作者： ERICSSON, S INRS TELECOMMUN VERDUNQUEBECCANADA

Hybrid predictive/transform coding is studied. The usual formulation is to first apply a unitary transform and then code the transform coefficients with independent DPCM coders, i.e., the prediction is performed in the transform domain. This structure is compared to spatial domain prediction, where a difference signal is formed in the spatial domain and then coded by a transform coder. A linear spatial domain predictor which minimizes the mean square prediction error also minimizes the mean square of each transform coefficient. The two structures are equivalent if the transform domain prediction scheme is extended to a more general predictor. Hence, the structure that gives the easiest implementation can be chosen. The spatial domain structure is preferred for motion compensation and for line interlaced video signals. Interframe hybrid coding experiments are performed on interlaced videophone scenes using an adaptive transform coder. Motion compensation gives a rate reduction of 25-35 percent compared to frame difference prediction with the same mean square error. The subjective advantage is even greater, since the "dirty window" effect is not present with motion compensation. It is important to perform the motion estimation with fractional pel accuracy. Field coding with a switched predictor using previous field in moving areas is an interesting alternative to frame coding with frame difference prediction.

关键词： transform coding Motion compensation Layout Bit rate Predictive coding Mean square error methods Motion estimation Signal Processing Society Communications Society Decoding

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Wiener filters in canonical coordinates for transform coding, filtering, and quantizing

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 1998年第3期46卷 647-654页

作者： Scharf, LL Thomas, JK Univ Colorado Dept Elect & Comp Engn Boulder CO 80309 USA Data Fus Corp Westminster CO 80021 USA

Canonical correlations are used to decompose the Wiener filter into a whitening transform coder, a Canonical filter, and a coloring transform decoder, The outputs of the whitening transform coder are called canonical coordinates;these are the coordinates that are reduced in rank and quantized in our finite-precision version of the Gauss-Markov theorem, Canonical correlations are, in fact, cosines of the canonical angles between a source vector and a measurement vector, They produce new formulas for error covariance, spectral flatness, and entropy.

关键词： adaptive filtering canonical coordinates canonical correlations quantizing transform coding Wiener filters

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OPTIMALLY ADAPTIVE transform coding

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IEEE TRANSACTIONS ON IMAGE PROCESSING 1995年第10期4卷 1358-1370页

作者： DONY, RD HAYKIN, S MCMASTER UNIV DEPT ELECT & COMP ENGNCOMMUN RES LABHAMILTONON L8S 4K1CANADA

The optimal linear block transform for coding images is well known to be the Karhunen-Loeve transformation (KLT), However, the assumption of stationarity in the optimality condition is far from valid for images, Images are composed of regions whose local statistics may vary widely across an image. While the use of adaptation can result in improved performance, there has been little investigation into the optimality of the criterion upon which the adaptation is based, In this paper we propose a new transform coding method in which the adaptation is optimal, The system is modular, consisting of a number of modules corresponding to different classes of the input data, Each module consists of a linear transformation, whose bases are calculated during an initial training period, The appropriate class for a given input vector is determined by the subspace classifier, The performance of the resulting adaptive system is shown to be superior to that of the optimal nonadaptive linear transformation. This method can also be used as a segmentor. The segmentation it performs is independent of variations in illumination, In addition,the resulting class representations are analogous to the arrangement of the directionally sensitive columns in the visual cortex.

关键词： transform coding Image coding Statistics Image segmentation Karhunen-Loeve transforms Neural networks Pulse modulation Vectors Adaptive systems Lighting

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Approximation algorithms for wavelet transform coding of data stream.

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IEEE TRANSACTIONS ON INFORMATION THEORY 2008年第2期54卷 811-830页

作者： Guha, Sudipto Harb, Boulos Univ Penn Dept Comp Informat Sci Philadelphia PA 19104 USA Google Inc New York NY 10011 USA

This paper addresses the problem of finding a B-term wavelet representation of a given discrete function f is an element of R-n whose distance from f is minimized. The problem is well understood when we seek to minimize the Euclidean distance between f and its representation. The first-known algorithms for finding provably approximate representations minimizing general f, distances (including l(infinity)) under a wide variety of compactly supported wavelet bases are presented in this paper. For the Haar basis, a polynomial time approximation scheme is demonstrated. These algorithms are applicable in the one-pass sublinear-space data stream model of computation. They generalize naturally to multiple dimensions and weighted norms. A universal representation that provides a provable approximation guarantee under all p-norms simultaneously;and the first approximation algorithms for bit-budget versions of the problem, known as adaptive quantization, are also presented. Further, it is shown that the algorithms presented here can be used to select a basis from a tree-structured dictionary of bases and find a B-term representation of the given function that provably approximates its best dictionary-basis representation.

关键词： adaptive quantization best basis selection compactly supported wavelets nonlinear approximation sparse representation streaming algorithms transform coding universal representation

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An approach to fast transform coding in software

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SIGNAL PROCESSING-IMAGE COMMUNICATION 1996年第1期8卷 3-11页

作者： Allen, JD Ricoh California Research Center 2882 Sand Hill Road Suite 115 Menlo Park CA 94025 USA

Techniques for fast image transform coding on 32-bit processors are described. The Reparameterized Suehiro transform is used to avoid multiplication;then two 16-bit arithmetic computations are accomplished simultaneously with 'paired arithmetic'. This reduces the effective cost of the 8-point DCT-III to about 11 additions, 9 subtractions and 15 shifts. With these techniques the Sun Sparcstation can perform JPEG compression and decompression at rates of 45 and 80 million pixels per minute respectively.

关键词： image compression transform coding fast transform parallel arithmetic Discrete Cosine transform

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Video Compression Using Generalized Binary Partitioning, Trellis Coded Quantization, Perceptually Optimized Encoding, and Advanced Prediction and transform coding

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2020年第5期30卷 1281-1295页

作者： Pfaff, Jonathan Schwarz, Heiko Marpe, Detlev Bross, Benjamin De-Luxan-Hernandez, Santiago Helle, Philipp Helmrich, Christian R. Hinz, Tobias Lim, W. -Q. Ma, Jackie Nguyen, Tung Rasch, Jennifer Schafer, Michael Siekmann, Mischa Venugopal, Gayathri Wieckowski, Adam Winken, Martin Wiegand, Thomas Heinrich Hertz Inst Nachrichtentech Berlin GmbH Fraunhofer Inst Telecommun D-10587 Berlin Germany Free Univ Berlin Inst Comp Sci D-14195 Berlin Germany Tech Univ Berlin Dept Telecommun Syst D-10623 Berlin Germany

In this paper, we describe a video coding design that enables a higher coding efficiency than the HEVC standard. The proposed video codec follows the design of block-based hybrid video coding, but includes a number of advanced coding tools. A part of the incorporated advanced concepts was developed by the Joint Video Exploration Team, while others are newly proposed. The key aspects of these newly proposed tools are the following. A video frame is subdivided into rectangles of variable size using a binary partitioning with variable split ratios. Three new approaches for generating spatial intra prediction signals are supported: A line-wise application of conventional intra prediction modes, coupled with a mode-dependent processing order, a region-based template matching prediction method and intra prediction modes based on neural networks. For motion-compensated prediction, a multi-hypothesis mode with more than two motion hypotheses can be used. In transform coding, mode dependent combinations of primary and secondary transforms are applied. Moreover, scalar quantization is replaced by trellis-coded quantization and the entropy coding of the quantized transform coefficients is improved. The intra and inter prediction signals can be filtered using an edge-preserving diffusion filter or a non-linear DCT-based thresholding operation. The video codec includes an adaptive in-loop filter for which one of three classifiers can be chosen on a picture basis. We also incorporated an optional encoder control, which adjusts the quantization parameters based on a perceptually motivated distortion measure. In a random access scenario, our proposed video codec achieves luma BD-rate savings between 32.5% for HDR HLG UHD and 39.6% for SDR UHD over the HEVC (HM software) anchor for different categories of test sequences.

关键词： Encoding transforms Video coding Tools transform coding Video codecs Quantization (signal) Video compression video coding High Efficiency Video coding (HEVC)

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A COMBINED-transform coding (CTC) SCHEME FOR MEDICAL IMAGES

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IEEE TRANSACTIONS ON MEDICAL IMAGING 1992年第2期11卷 196-202页

作者： ZHANG, YQ LOEW, MH PICKHOLTZ, RL GEORGE WASHINGTON UNIV DEPT ELECT ENGN & COMP SCIWASHINGTONDC 20052

transform coding has been applied successfully for radiological image compression in the picture archival and communication system (PACS) and other medical applications. However, the blocking artifact caused by the block implementation in conventional transform coding is undesirable in the clinical environment. A combined-transform coding (CTC) scheme is proposed in this paper to reduce this artifact and hence achieve better subjective performance. In the combined-transform coding scheme, the original image is first divided into two sets of image planes that have different stochastic properties. The upper image set (UIS) contains the most significant information and tends to be highly correlated, and the lower image set (LIS) contains the less significant information. The UIS is coded noiselessly without dividing into blocks and the LIS is coded by conventional block transform coding. Since the correlation in UIS is significantly reduced, the interblock correlation and hence the blocking artifact are reduced. This paper first describes the proposed CTC scheme and investigates its information-theoretic properties. Then computer simulation results for a class of AP view chest X-ray images are presented. The comparison between the CTC scheme and the conventional discrete cosine transform (DCT) and discrete Walsh-Hadmard transform (DWHT) is made to demonstrate the performance improvement of the proposed scheme. The concept of combined-coding is also used for perfect reconstruction of the class of chest X-ray images and slight improvement in the compression performance is observed. Finally, we point out that the CTC scheme has advantages in medical image transmission over a noisy channel or a packet-switched network in case of channel error and packet loss due to the layered structure of the proposed approach.

关键词： transform coding coding discrete cosine transforms Scheme Medical imaging block effect block transform Hence performance boost

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Optimal Adaptive Multistage Image transform coding

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1991年第4期1卷 308-+页

作者： Aghagolzadeh, Sabzali Ersoy, Okan K. Purdue Univ Sch Elect Engn W Lafayette IN 47907 USA Tabriz Univ Sch Elect Engn Tabriz Iran IIT Chicago IL 60616 USA

Adaptive multistage image transform coding is discussed and an optimal method is introduced for bit allocation. The optimality is in the sense of minimizing the mean square reconstruction error with a given total number of bits and a given number of stages. The statistics of the coefficients in different stages and marginal analysis are used to optimize the division of the total number of bits among the stages. Experimental results indicate that, with two stages, more than 14% improvement for one clan and more than 11076 improvement for multiclasses is achieved in mean square reconstruction error over one-stage image transform coding. Higher improvements are achieved with three stages. The reconstructed images with multistage coding are subjectively much more preferable than the reconstructed Images with one-stage coding.

关键词： transform coding Image coding Image reconstruction Karhunen-Loeve transforms Bit rate Discrete transforms Discrete cosine transforms Statistics Statistical analysis Decorrelation

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Identification of transform coding Chains

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2016年第3期25卷 1109-1123页

作者： Tagliasacchi, Marco Visentini-Scarzanella, Marco Dragotti, Pier Luigi Tubaro, Stefano Politecn Milan Dipartimento Elettron & Informaz I-20133 Milan Italy Univ London Imperial Coll Sci Technol & Med Commun & Signal Proc Grp London SW7 2AZ England Toshiba Res & Dev Ctr Multimedia Lab Kawasaki Kanagawa 2110021 Japan

transform coding is routinely used for lossy compression of discrete sources with memory. The input signal is divided into N-dimensional vectors, which are transformed by means of a linear mapping. Then, transform coefficients are quantized and entropy coded. In this paper, we consider the problem of identifying the transform matrix as well as the quantization step sizes. First, we study the case in which the only available information is a set of P transform decoded vectors. We formulate the problem in terms of finding the lattice with the largest determinant that contains all observed vectors. We propose an algorithm that is able to find the optimal solution and we formally study its convergence properties. Three potential realms of application are considered as example scenarios for the proposed theory: 1) parameter retrieval in the presence of a chain of two transform coders;2) image tampering identification;and 3) parameter estimation for predictive coders. We show that, despite their differences, all three scenarios can be tackled by applying the same fundamental methodology. Experiments on both the synthetic data and the real images validate the proposed approach.

关键词： transform coding image coding image forensics

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A non-adaptive optimal transform coding system

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IEICE TRANSACTIONS ON COMMUNICATIONS 2003年第11期E86B卷 3266-3277页

作者： Hsieh, CH Chien Kuo Inst Technol Dept Elect Engn Changhua 500 Taiwan

In this paper, a, non-adaptive optimal transform (NAOT) coding system is proposed. Note that the energy-invariant property in an orthogonal transformation and that the mean squared error (MSE) of a reconstructed image is proportional to the total energy of transform coefficients discarded in the coding process. The NAOT coding system is developed and proved optimal in the sense of minimum average energy loss. Basically, the proposed coding system consists of the following steps. First, obtain the average energy image block from transform image blocks. Second, sort the average energy image block in the descending order by energy where the sorted indices are recorded. Third, specify the number of coefficients, M, to be retained in the coding process. Fourth, the first M sorted indices form a set denoted as S-M through which the problem of optimal feature selection in transform coding is solved. Fifth, find a fixed mask Am from set S-M which is then used to select M significant transform coefficients in image blocks. Finally, the M selected coefficients are quantized and coded by the order as in S-M. To verify the NAOT coding system, simulations are performed on several examples. In the simulation, the optimality and the optimal feature selection in the NAOT coding system are justified. Also, the effectiveness of the proposed S-M-based selection approach is compared with the zigzag scan used in the JPEG. For fair comparison, the JPEG is modified to code only M transform coefficients. Simulation results indicate that the performance Of S-M-based selection approach is superior or identical to the zigzag scan in terms of PSNR. Finally, the performance comparison between the NAOT coding system and the JPEG is made. It suggests that the proposed NAOT coding system is able to trade very little PSNR for significant bit rate reduction when compared with the JPEG. Or it can be said that the JPEG wastes much bit rate to improve very little PSNR on the reconstructed image, when c

关键词： optimality transform coding image compression coefficient selection JPEG

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