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Multidimensional Signal Processing Workshop

作者： S. Mallat N. Treil S. Zhong Courant Institute New York University NY USA Ecole Nationale Superieure des Telecommunications Paris France

Summary form only given, as follows. A multiresolution edge detection can be performed with a wavelet transform. Indeed, for some particular wavelets, the wavelet transform of an image provides the local gradient of the image at different resolutions. A multiresolution edge detection is therefore equivalent to a detection of local extrema in the image wavelet transform (local extrema of the image gradient). It is shown that one can build a complete image representation by recording the value and the position of these local extrema on a dyadic sequence of resolutions: 1/2, 1/4, 1/8 etc. An iterative procedure that reconstructs the image from these local extrema is described. The algorithm is based on the reproducing kernal of a wavelet transform; it is numerically stable. This reconstruction shows that an image can be coded from the edges which appear on a dyadic sequence of resolutions, without losing any information. Such an adaptive coding is useful for pattern recognition but also for data compression. Indeed, the edges of an image can be efficiently coded into chains with predictive techniques.

关键词： Image coding Wavelet transforms Image resolution Image edge detection Image reconstruction Image representation Iterative algorithms adaptive coding Pattern recognition Data compression

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adaptive code excited linear predictive coder (ACELPC)

Adaptive code excited linear predictive coder (ACELPC)

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

作者： J. Menez C. Galand M. Rosso F. Bottau Lassy UA CNRS 814 Nice University Nice France IBM Laboratory La Gaude France

Code-excited linear predictive coding (CELP) is a recent vector waveform coding technique which permits the encoding of telephone speech with high quality at very low bit rates. The authors show that they can further reduce the computational complexity and the storage requirements of the coder, while improving the perceptual quality of the reconstructed speech. These improvements are achieved by two key factors: the implementation of a noise-shaping effect by alternate estimation of the short-term predictor coefficients, and the use of a fixed/adaptive codebook together with a long-term predictor.< >

关键词： adaptive coding Noise shaping Speech synthesis Speech enhancement Speech coding Computational complexity Bit rate Signal synthesis Speech analysis Books

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adaptive rate error control through the use of diversity combining and majority logic decoding in a hybrid-ARQ protocol

Adaptive rate error control through the use of diversity com...

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MILCOM, Military Communications Conference

作者： S.B. Wicker School of Electrical Engineering Georgia Institute of Technology Atlanta GA USA

The author demonstrates an adaptive rate coding system based on the majority logic decoding of convolutional codes. The proposed system retains the high-data-rate capability of FEC (forward error correction) majority logic decoders while providing an adaptive code rate and a significant improvement in error protection through the incorporation of diversity combining and hybrid-ARQ (automatic repeat request) techniques. It is shown through analysis and simulation that this error control system provides a high level of data reliability at the expense of a minimal reduction in throughput.< >

关键词： Diversity reception Programmable control adaptive control Error correction Decoding Forward error correction adaptive systems Convolutional codes Automatic logic units adaptive coding

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DYNAMIC-HISTORY PREDICTIVE COMPRESSION

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INFORMATION SYSTEMS 1988年第1期13卷 129-140页

作者： WILLIAMS, RN Department of Computer Science The University of Adelaide G.P.O. Box 498 Adelaide 5001 South AustraliaAustralia

The problem of compressing a discrete finite ergodic source sequence is approached from a predictive point of view. An algorithm is described that dynamically builds a conditional probability tree by adding leaves in proportion to their potential for reducing the entropy of the tree. This results in a tree that is containable but which can still adapt to unusual source characteristics. An implementation of the algorithm produced compression competitive with other contemporary data compression algorithms.

关键词： Data compression prediction variable order Markov model arithmetic coding adaptive coding

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RECURSIVE TEMPORAL FILTERING AND FRAME RATE REDUCTION FOR IMAGE-coding

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1987年第7期5卷 1155-1165页

作者： CHEN, WH HEIN, D Compression Laboratories Inc. San Jose CA USA

The effect of temporal recursive filtering and frame rate reduction on a sequence of moving images is investigated. Following a well-known first-order Markov model for the temporal domain data, the effect of filtering and frame rate reduction on the values of variance, correlation coefficient, filtering distortion, and interframe prediction error are mathematically derived. The validity of these derivations is verified by the experimental results using a CCITT standard sequence which closely follows the first-order Markov model. The effect of temporal filtering and frame rate reduction to the coding rate is examined by encoding the CCITT standard sequence using a combined interframe and intraframe Scene adaptive coding system. At a frame rate of 30 frames per second, a 2:1 reduction in coding rate is obtained with a filtering coefficient of 0.5. At a frame rate of 10 frames per second, an additional reduction factor of nearly 2 is obtained using the same filtering coefficient. Selected images are presented to demonstrate the subjective effect.

关键词： Filtering Image coding Layout adaptive coding Pixel Spatial resolution Predictive models Testing Mathematical model adaptive filters

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IMPROVEMENTS OF TRANSFORM coding ALGORITHM FOR MOTION-COMPENSATED INTERFRAME PREDICTION ERRORS - DCT SQ coding

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1987年第7期5卷 1068-1078页

作者： KANEKO, M HATORI, Y KOIKE, A KDD Research and Development Laboratories Inc. Tokyo Japan

A new hybrid coding method for transmitting videoconferencing images at a bit rate 384 kbits/s is proposed. Considering the characteristics of motion-compensated interframe prediction errors for typical videoconferencing scenes, a filter is introduced to separate pulsive components on which conventional discrete cosine transform (DCT) coding method does not work well. These separated pulsive components are coded by using scalar quantization (SQ). The remainder are DCT coded. For DCT coefficients, an adaptive coding method based on the classification of DCT coefficients is applied in order to improve the coding performance. Since the proposed method employs both DCT coding and SQ of prediction errors, it is named "DCT/SQ coding method." Experimental results show that the DCT/SQ coding method is effective to reduce so-called mosquito effects, and thus it can improve the quality of decoded images.

关键词： Transform coding Discrete cosine transforms Image coding Teleconferencing Bit rate Layout Filters Quantization adaptive coding Decoding

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CHAOTIC BEHAVIOR OF adaptive RECURSIVE FILTERS - APPLICATION TO TELEPHONE SIGNAL COMPRESSION

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ANNALES DES TELECOMMUNICATIONS-ANNALS OF TELECOMMUNICATIONS 1987年第5-6期42卷 285-299页

作者： JAIDANESAIDANE, M MACCHI, O 1.Laboratoire des Signaux et Systèmes CNRS-ESE Plateau du Moulon 91190 Gif-sur-Yvette France

Le filtrage adaptatif propose des méthodes itératives simples au problème d’extraction d’un signal utile par filtrage linéaire d’une observation corrélée au signal utile. Lorsque l’observation contient des valeurs passées de la sortie du filtre (structure récursive), le filtrage adaptatif devient une opération non linéaire qui peut engendrer des comportements complexes bien que l’adaptation soit un classique dérivé du gradient. De tels comportements sont observés dans un cas particulier : la prédictionArma adaptative à entrée sinuso?dale. Une vitesse d’adaptation lente entra?ne un comportement quasipériodique lié au caractère localement instable du prédicteur. Ce phénomène dit d’autostabilisation persiste à mesure que la vitesse d’adaptation augmente. Son analyse se complique alors considérablement car le comportement du prédicteur devient chaotique. Comme exemple d’application, la numérisation des signaux téléphoniques qui utilise la prédictionArma adaptative, montre la nécessité de ma?triser le comportement qualitatif des solutions fournies par l’outil filtrage adaptatif.

关键词： Chaos Filtre recursif Filtre adaptatif Opérateur non linéaire Modèle autorégressif Moyenne mobile Prédicteur Compression bande passante Signal vocal Théorie signal Mic différentiel Codage adaptatif Chaos Recursive filter adaptive filter Non linear operator Autoregressive model Moving average Predictor Passband compression Voice frequency signal Signal theory DifferentialPcm adaptive coding

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On predictive least squares filtering

On predictive least squares filtering

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

作者： Tie-Jun Shan Information Systems Laboratory University of Stanford Stanford CA USA

In this paper, a class of filters based on the Predictive Least Squares principle recently suggested by Rissanen are proposed and studied. The proposed filtering technique provides a consistent estimate of the number of parameters for a Gaussian regression model while still minimizing the accumulated least squares error. Thus, the proposed filters combine model estimation and parameter estimation to provide optimal prediction and estimation. The proposed Predictive Least Squares filtering has potential application for adaptive coding, spectrum estimation, harmonic retrieval and many other digital signal processing areas.

关键词： Least squares methods Filtering Least squares approximation Parameter estimation Predictive models adaptive filters Digital filters adaptive coding Spectral analysis Power harmonic filters

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adaptive discrete cosine transform coding with vector quantization for color images

Adaptive discrete cosine transform coding with vector quanti...

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

作者： K. Aizawa H. Harashima H. Miyakawa Department of Electrical Engineering University of Tokyo Tokyo Japan

A new vector quantization scheme in discrete cosine transform domain, named DCT-VQ and its application to color image coding are described. In this scheme, DCT-domain is partitioned into vectors which are normalized and vector-quantized using universal vector quantizers designed with multidimensional Laplacian distribution. adaptive coding scheme is also introduced to obtain better reconstruction of images. The color image coder employs the above scheme and encodes separately three components converted from R,G,B signals. The simulations have shown that adaptive DCT-VQ exhibits better performance than a conventional adaptive cosine transform coding with scalar quantization. The decomposition of DCT-block into vectors results in much less complex coder than a vector quantizer in original space domain.

关键词： Discrete cosine transforms Image coding Vector quantization Color Multidimensional systems Laplace equations adaptive coding Image reconstruction Image converters Transform coding

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FINITE PRECISION IMPLEMENTATION OF adaptive QUANTIZATION

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ANNALES DES TELECOMMUNICATIONS-ANNALS OF TELECOMMUNICATIONS 1986年第5-6期41卷 252-259页

作者： LEGUYADER, A ***-LAA route de Trégastel 22301 Lannion Cedex

Dans cet article, Fauteur décrit l’implantation en précision finie de la quantification adaptative par comparaison à des seuils de décision puis propose un nouvel algorithme dit à erreur de quantification minimale. Associé à des prédicteurs adaptatifs dans les codeursmicda, ce dernier conduit à des performances optimales tant en ce qui concerne le codage des faibles signaux que dans la configuration de codages-décodages successifsmicda en cascade.

关键词： Quantification signal Codage adaptatif mic différentiel Erreur arrondi Algorithme adaptatif Compression information Traitement parole Signal quantizing adaptive coding Differentialpcm Rounding error adaptive algorithm Information compression Speech processing

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