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Conference on Visual Communications and Image Processing 2003

作者： Keissarian, F United Arab Emirates Univ Dept Elect Engn Al Ain U Arab Emirates

ISBN: (纸本)0819450235

A new quadtree segmented predictive image coding technique is presented in this paper for exploiting the correlation between adjacent image blocks and uniformity in variable block size image blocks. For exploiting correlation between adjacent image blocks, a predictive coding technique is used for reducing the inter block correlation. The proposed quadtree technique decomposes an image into variable size block, and each segmented block is then coded at a different bit rate according to the level of visual activity inside the block. A novel classification scheme, which operates based on the distribution of the block residuals, is employed to determine the activity level inside the block. hi this method, the orientation of the pattern appearing inside the block will be computed as an aid to the classification. To preserve edge integrity, a block pattern-based coding technique is proposed and incorporated to the predictive coding method for coding the high-activity blocks of the segmented image. The use of a set of parameters associated with the pattern appearing inside a high activity block at the receiver, together with the inter block correlation information. reduce the cost of instruction and saves the encoding time. Experiments have been conducted to compare with other predictive and quadtree- based techniques. Results show a lower bit rate at competitive reconstruction quality.

关键词： image compression quadtree decomposition predictive coding pattern-based classification

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Two-channel predictive multiple description coding

Two-channel predictive multiple description coding

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IEEE International Conference on Image Processing

作者： A. Jagmohan A. Sehgal N. Ahuja IBM Thomas J. Watson Research Center USA University of Illinois USA

This paper presents a multiple description (MD) video codec based on the principles side-information coding. In particular, we highlight certain key components of the codec design that contribute significantly to the rate-distortion performance of the proposed codec. These include the use of randomized permutations of the quantization codebook in conjunction with binary LDPC codes for partitioning the available bit-rate among the coefficient bit-planes. Another key component of the proposed codec is the use of pdf estimation for improved decoder reconstruction. Lastly, we use a bank of sequential LDPC decoders to efficiently decode the transmitted coset information. Empirical evaluation demonstrates the superior performance of the proposed codec for the communication of encoded video over packet erasure channels.

关键词： Decoding Parity check codes Streaming media Video codecs Video coding Degradation predictive coding Video sequences Entropy coding Computer architecture

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Lossless Multi-channel EEG Compression

Lossless Multi-channel EEG Compression

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Proceedings of 2006 IEEE International Symposium on Circuits and Systems,Volume 4

作者： Yodchanan Wongsawat Soontorn Oramtara Toshihisa Tanaka K. R. Rao Department of Electrical Engineering University of Texas at Arlington Department of Electrical and Electronic Engineering RIKEN Brain Science Institute Department of Electrical Engineering University of Texas at Arlington USA

This paper presents a method for losslessly compressing multi-channel electroencephalogram signals. The Karhunen-Loeve transform is used to exploit the inter-correlation among the EEG channels. The transform is approximated using lifting scheme which results in a reversible realization under finite precision processing. An integer time-frequency transform is applied to further minimize the temporal redundancy.

关键词： Electroencephalography Karhunen-Loeve transforms Decorrelation Signal processing Signal analysis Compression algorithms predictive coding Brain modeling Electrodes Scalp

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Strategies for quadtree predictive image coding

Strategies for quadtree predictive image coding

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IEEE International Conference on Image Processing

作者： K.M. Holt D.L. Neuhoff Department of Electrical Engineering and Computer Science The University of Michigan Ann Arbor MI USA

A new image coder is presented in which an image is divided into blocks, each block is quadtree segmented, and each segment is coded using a form of predictive coding. We provide nearly-optimal segmentation and quantization rules for this framework, as well as an iterative codebook design algorithm. In simulations, our new system comes within 1 dB of JPEG 2000 and outperforms JPEG by about 1.5 dB at moderate rates and up to 4.5 dB at low rates. Additionally, our method captures edges better and has potentially lower complexity than transform-based methods.

关键词： Image coding Image segmentation Quantization Decoding Image reconstruction predictive coding Wavelet transforms Algorithm design and analysis Iterative algorithms Discrete cosine transforms

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Error resilience video transcoding for wireless communications

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IEEE WIRELESS COMMUNICATIONS 2005年第4期12卷 14-21页

作者： Vetro, A Xin, J Sun, HF Mitsubishi Elect Res Labs Cambridge MA USA

Video communication through wireless channels is still a challenging problem due to the limitations in bandwidth and the presence of channel errors. Since,many video sources are originally coded at a high rate and without considering,the different channel conditions that may be encountered later, a means to repurpose this content for delivery over a dynamic wireless channel is needed. Transcoding is typically used to reduce the rate and change the format of the originally encoded video source to match network conditions and terminal capabilities. Given the existence of channel errors that can easily corrupt video quality, there is also the need to make the bitstream more resilient to transmission errors. In this article we provide an overview of the error resilience tools found in today's video coding standards and describe a variety of techniques that may be used to achieve error-resilient video transcoding.

关键词： Resilience Transcoding Wireless communication Video compression Decoding predictive coding Video coding Redundancy Error correction Error correction codes

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Information theory, novelty and hippocampal responses: unpredicted or unpredictable?

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NEURAL NETWORKS 2005年第3期18卷 225-230页

作者： Strange, BA Duggins, A Penny, W Dolan, RJ Friston, KJ Inst Neurol Wellcome Dept Imaging Neurosci Funct Imaging Lab London WC1N 3BG England Inst Cognit Neurosci London WC1N 3AR England

Shannon's information theory provides a principled framework for the quantitative analysis of brain responses during the encoding and representation of event streams. In particular, entropy measures the expected uncertainty of events in a given context. This contextual uncertainty or unpredictability may, itself, be important for balancing [bottom-up] sensory information and [top-down] prior expectations during perceptual synthesis. Using event-related functional magnetic resonance imaging (fMRI), we found that the anterior hippocampus is sensitive to the entropy of a visual stimulus stream. In contrast, activity in an extensive bilateral cortico-thalamic network was dictated by the surprise or information associated with each particular stimulus. In short, we show that the probabilistic structure or context in which events occur is an important predictor of hippocampal activity. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： information theory entropy surprise novelty predictive coding functional magnetic resonance imaging hippocampus

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Robust low-delay audio coding using multiple descriptions

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IEEE TRANSACTIONS ON SPEECH AND AUDIO PROCESSING 2005年第5期13卷 1014-1024页

作者： Schuller, G Kovacevic, J Masson, F Goyal, VK Fraunhofer Inst IDMT D-98693 Ilmenau Germany Carnegie Mellon Univ Dept Biomed Engn & Elect & Comp Engn Pittsburgh PA 15213 USA ELCA Informat Geneva Switzerland MIT Res Lab Elect Cambridge MA 02139 USA

This paper proposes an encoding method for high-quality, low-delay audio communication that is robust to losses in packetized transmission. Robustness is provided by a multiple description vector quantization (MDVQ) technique that is designed to minimize the mean-squared error (MSE). The key to applying this technique effectively is the use of psycho-acoustically controlled pre- and post-filters that make the mean-squared quantization error perceptually relevant. Experiments show that the MDVQ-based encoder yields better results-in both MSE and subjective audio quality-than simple alternative coders with the same low delay.

关键词： audio coding error robustness LMS low delay multiple descriptions predictive coding psycho-acoustics

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Visual speech speeds up the neural processing of auditory speech

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PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2005年第4期102卷 1181-1186页

作者： van Wassenhove, V Grant, KW Poeppel, D Univ Maryland Neurosci & Cognit Sci Program College Pk MD 20742 USA Univ Maryland Dept Biol College Pk MD 20742 USA Univ Maryland Dept Linguist College Pk MD 20742 USA Walter Reed Army Med Ctr Auditory Visual Speech Lab Washington DC 20307 USA

Synchronous presentation of stimuli to the auditory and visual systems can modify the formation of a percept in either modality. For example, perception of auditory speech is improved when the speaker's facial articulatory movements are visible. Neural convergence onto multisensory sites exhibiting supra-additivity has been proposed as the principal mechanism for integration. Recent findings, however, have suggested that putative sensory-specific cortices are responsive to inputs presented through a different modality. Consequently, when and where audiovisual representations emerge remain unsettled. In combined psychophysical and electroencephalography experiments we show that visual speech speeds up the cortical processing of auditory signals early (within 100 ms of signal onset). The auditory-visual interaction is reflected as an articulator-specific temporal facilitation (as well as a nonspecific amplitude reduction). The latency facilitation systematically depends on the degree to which the visual signal predicts possible auditory targets. The observed auditory-visual data support the view that there exist abstract internal representations that constrain the analysis of subsequent speech inputs. This is evidence for the existence of an "analysis-by-synthesis" mechanism in auditory-visual speech perception.

关键词： EEG multisensory predictive coding

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A progressive transmission capable diagnostically lossless compression scheme for 3D medical image sets

A progressive transmission capable diagnostically lossless c...

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4th International Conference on Computer Vision, Pattern Recognition and Image Processing

作者： Qi, XJ Tyler, JM Utah State Univ Dept Comp Sci Logan UT 84322 USA Louisiana State Univ Dept Comp Sci Baton Rouge LA 70803 USA

This paper presents a novel and efficient diagnostically lossless compression for 3D medical image sets. This compression scheme provides the 3D medical image sets with a progressive transmission capability. An automated filter-and-threshold based preprocessing technique is used to remove noise outside the diagnostic region. Then a wavelet decomposition feature vector based approach is applied to determine the reference image for the entire 3D medical image set. The selected reference image contains the most discernible anatomical structures within a relative large diagnostic region. It is progressively encoded by a lossless embedded zerotree wavelet method so the validity of an entire set can be determined early. This preprocessing technique is followed by an optimal predictor plus a 1st-level integer wavelet transform to de-correlate the 3D medical image set. Run-length and arithmetic coding are used to further remove coding redundancy. This diagnostically lossless compression method achieves an average compression of 2.1038, 2.4292, and 1.6826 bits per pixel for three types of 3D magneticresonance image sets. The integrated progressive transmission capability degrades the compression performance by an average of 7.25%, 6.60%, and 4.49% for the above three types. Moreover, our compression without and with progressive transmission achieves better compression than the state-of-the-art. (c) 2005 Elsevier Inc. All rights reserved.

关键词： progressive transmission predictive coding integer wavelet transformation lossless embedded zerotree wavelet run-length encoding

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A progressive transmission capable diagnostically lossless compression scheme for 3D medical image sets

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INFORMATION SCIENCES 2005年第3期175卷 217-243页

作者： Qi, XJ Tyler, JM Utah State Univ Dept Comp Sci Logan UT 84322 USA Louisiana State Univ Dept Comp Sci Baton Rouge LA 70803 USA

关键词： progressive transmission predictive coding integer wavelet transformation lossless embedded zerotree wavelet run-length encoding

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