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Fast rate-distortion optimisation algorithm for motion-compensated transform coding of video

ELECTRONICS LETTERS 2000年第4期36卷 305-306页

作者： Shen, JD Chan, WY IIT Dept Elect & Comp Engn Chicago IL 60616 USA

A reduced-complexity but effective search scheme for rate-distortion (RD) optimisation of motion vector and displaced-frame-difference coding is proposed. Through predicting the relative order of the RD-Lagrange rests, a large proportion of suboptimal displacement Vector positions are eliminated. In comparison with a popular H.263 test model, the proposed scheme leads to a similar to 0.5dB improvement in the peak signal-to-noise ratio.

关键词： transform coding rate distortion theory peak signal-to-noise ratio Image and video coding suboptimal displacement vector positions H.263 test model rate-distortion optimisation algorithm motion-compensated transform coding Video signal processing RD-Lagrange costs motion compensation video coding displaced-frame-difference coding

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Multirate filter banks and transform coding gain

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 1998年第7期46卷 2041-2044页

作者： Kok, CW Nguyen, TQ Univ Wisconsin Dept Elect & Comp Engn Madison WI 53706 USA Boston Univ Dept Elect & Comp Engn Boston MA 02215 USA

An analytical derivation of quantization error in biter banks using additive and signal dependent noise models is *** coding gain over PCM-is derived for both noise models. Interesting properties of coding gain in optimized filter banks with an AR(1) input signal model, asymptotic performance of multirate systems, and the analytical constraints required to achieve such performance are discussed. Connections to the recent developments of optimal subband systems are presented.

关键词： Channel bank filters transform coding Filter bank Image coding Quantization Additive noise Image reconstruction Shape Signal analysis Phase change materials

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Dithered GMD transform coding

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IEEE SIGNAL PROCESSING LETTERS 2010年第5期17卷 457-460页

作者： Weng, Ching-Chih Vaidyanathan, P. P. Su, Han-I CALTECH Pasadena CA 91109 USA Stanford Univ Stanford CA 94930 USA

The geometric mean decomposition (GMD) transform coder (TC) was recently introduced and was shown to achieve the optimal coding gain without bit loading under the high bit rate assumption. However, the performance of the GMD transform coder is degraded in the low rate case. There are mainly two reasons for this degradation. First, the high bit rate quantizer model becomes invalid. Second, the quantization error is no longer negligible in the prediction process when the bit rate is low. In this letter, we introduce dithered quantization to tackle the first difficulty, and then redesign the precoders and predictors in the GMD transform coders to tackle the second. We propose two dithered GMD transform coders: the GMD subtractive dithered transform coder (GMD-SD) where the decoder has access to the dither information and the GMD nonsubtractive dithered transform coder (GMD-NSD) where the decoder has no knowledge about the dither. Under the uniform bit loading scheme in scalar quantizers, it is shown that the proposed dithered GMD transform coders perform significantly better than the original GMD coder in the low rate case.

关键词： Bit allocation dithered quantization geometric mean decomposition linear prediction transform coding

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IMPROVEMENT ON IMAGE transform coding BY REDUCING INTERBLOCK CORRELATION

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IEEE TRANSACTIONS ON IMAGE PROCESSING 1995年第8期4卷 1146-1150页

作者： LIM, KW CHUN, KW RA, JB Dept. of Electr. Eng. Korea Adv. Inst. of Sci. and Technol. Taejon.

In this correspondence, He try to improve transform coding efficiency by alleviating interblock correlation due to the small size of block. The proposed method needs minor modification from conventional transform coding techniques such as JPEG, and reduces information loss in the coding procedure for a given bit rate. Simulation results demonstrate that the method drastically diminishes the blocking effects and enhances the subjective visual quality compared with such existing algorithms as JPEG and LOT.

关键词： transform coding Discrete cosine transforms Image coding Bit rate Quantization Image converters Compaction Facsimile Telegraphy Discrete transforms

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SOFT DECISION DEMODULATION AND transform coding OF IMAGES

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IEEE TRANSACTIONS ON COMMUNICATIONS 1983年第4期31卷 572-577页

作者： REININGER, RC GIBSON, JD Department of Electrical Engineering Texas A and M University College Station TX USA

This paper describes a transform image coding system that uses soft decision demodulation to control channel errors. In soft decision demodulation, if certain received bits of a codeword representing a coefficient are unreliable, then the codeword is rejected and the corresponding coefficient is replaced with an estimate. By monitoring the three highest energy DCT coefficients, the reconstructed image quality can be improved for a channel with a bit error probability of 10 -2 .

关键词： Demodulation transform coding Image coding Control systems Error correction Monitoring Discrete cosine transforms Image reconstruction Image quality Error probability

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IMPROVED DECODER FOR transform coding WITH APPLICATION TO THE JPEG BASE-LINE SYSTEM

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IEEE TRANSACTIONS ON COMMUNICATIONS 1992年第2期40卷 251-254页

作者： WU, SW GERSHO, A Department of Electrical and Computer Engineering Center for Information Processing Research University of California Santa Barbara CA USA

transform coding, a simple yet efficient image coding technique, has been adopted by the Joint Photographic Experts Group (JPEG) as the basis for an emerging coding standard for compression of still images. However, for any given transform encoder, the conventional inverse transform decoder is suboptimal. Better performance can be obtained by a nonlinear interpolative decoder that performs table lookups to reconstruct the image blocks from the code indexes. Each received code index of an image block addresses a particular codebook to fetch a component vector. The image block can be reconstructed as the sum of the component vectors for that block. An iterative algorithm for designing a set of locally optimal codebooks is developed. Computer simulation results demonstrate that this improved decoding technique can be applied in the JPEG baseline system to decode enhanced quality pictures from the bit stream generated by the standard encoding scheme.

关键词： transform coding Image coding Iterative decoding Image reconstruction Table lookup Iterative algorithms Algorithm design and analysis Computer simulation Streaming media Encoding

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CONSTRAINED transform coding AND SURFACE FITTING

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IEEE TRANSACTIONS ON COMMUNICATIONS 1983年第5期31卷 717-726页

作者： WATSON, LT HARALICK, RM ZUNIGA, OA VIRGINIA POLYTECH INST & STATE UNIV DEPT ELECT ENGNBLACKSBURGVA 24061

A constrained transform coding procedure is developed which is a combination of transform coding with differential pulse code modulation. The algorithm avoids block boundary mismatch errors, yet retains the coding efficiency of transform coding. A general theory of constrained transform coding is developed which includes the discrete cosine transformation and tensor products of splines as special cases. Results using the cosines and spines are given for two images. A complete discussion of the necessary linear algebra background is also given.

关键词： Surface fitting transform coding Pulse modulation Modulation coding Phase change materials Pulse measurements Constraint theory Linear algebra Solid modeling Random number generation

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EFFECTS OF TRANSMISSION ERRORS ON THE MEAN-SQUARED ERROR PERFORMANCE OF transform coding SYSTEMS

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IEEE TRANSACTIONS ON ACOUSTICS SPEECH AND SIGNAL PROCESSING 1979年第5期27卷 531-537页

作者： ZELINSKI, R AEG Telefunken Ulm Germany

This study presents an analysis of the effects of statistically independent channel transmission errors on the mean-squared error performance of transform coding (TC) systems. A comparison with performance of corresponding PCM systems is given also taking into consideration the bounds on performance improvement if additional error-protection schemes are implemented. The probability density functions of the quantizer input signals are described by different model density functions which are of importance for speech and picture encoding systems. The natural binary code, the Gray code, the folded binary code, and the minimum distance code are investigated as binary representations of the quantizer reconstruction values. In addition to the analysis, simulation results for transform coding of speech signals are presented. The results show a close agreement with the theoretical performance predicted from the analysis. The main results of this study, which are valid for most cases of practical interest, can be stated as follows: TC systems are no more sensitive to channel errors than PCM systems when operating without error protection, i.e., both systems yield nearly the same value of channel error variance. The performance of a TC system is, however, significantly superior to that of a PCM system, if the code words of both systems are error-protected similarly. The channel error variance of the TC system is by a gain factor G TC smaller than that of a corresponding PCM system in the most favorable case. The gain G TC is the factor by which the quantization distortion in a TC system is reduced relative to PCM.

关键词： transform coding Phase change materials Performance analysis Binary codes Speech analysis Probability density function Density functional theory Reflective binary codes Signal analysis Analytical models

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REAL-TIME SIMULATION OF ADAPTIVE transform coding

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IEEE TRANSACTIONS ON ACOUSTICS SPEECH AND SIGNAL PROCESSING 1981年第2期29卷 147-154页

作者： COX, RV CROCHIERE, RE Department of Acoustics Research Bell Laboratories Inc. Murray Hill NJ USA

Adaptive transform coding (ATC) has recently been proposed as a technique for speech coding at bit rates in the range of 9.6- 16 kbits/s. In this paper we report on two new developments: 1) the use of a homomorphic vocoder model for the "side-information" channel in ATC and 2) a real-time simulation of ATC on an array processing computer. It is shown that the choice of the homomorphic "side-information" model leads to a convenient form of the ATC algorithm for real-time block processing using array processing techniques. It is also shown that the log spectrum output of the homomorphic model is in a convenient form for input to both the bit assignment algorithm in ATC (which becomes a straightforward quantization operation) and the quantization of the transform coefficients (which may be done in the log domain). An array processor simulation of this form of the algorithm has been implemented and it serves as a highly useful and convenient tool for studying the ATC algorithm in real time in a Fortran programming environment. It has allowed us, for the first time, to perform actual telephone conversations over a transform coder. The quality of this ATC algorithm was found to be essentially equivalent to that of a previous version using an LPC vocoder model for the side information.

关键词： transform coding Vocoders Array signal processing Quantization Speech coding Bit rate Computational modeling Computer simulation Programming environments Telephony

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SPATIAL transform coding OF COLOR IMAGES

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IEEE TRANSACTIONS ON COMMUNICATION TECHNOLOGY 1971年第6期CO19卷 980-&页

作者： PRATT, WK University of Southern California Los Angeles CA USA

During the past few years several monochromeimage transform-coding systems have been developed. In these systems, a quantized and coded version of a spatial unitary transform of an image is transmitted over a channel, rather than an image itself. In this paper the transform-coding concept has been applied to the coding of color images represented by three primary color planes of data. The principles of spatial transform coding are reviewed and the merits of various methods of color-image representation are discussed. A performance analysis is presented for the color-image transform-coding system. Results of a computer simulation of the coding system are also given. It is shown that, by transform coding, the chrominance content of a color image can be coded with an average of 1.0 bits per element or less without serious degradation. If luminance coding is also employed, the average rate reduces to about 2.0 bits per element or less.

关键词： transform coding Color Image coding Bandwidth Signal processing Communications technology Performance analysis Computer simulation Degradation Image sensors

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