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DPCM ENCODING OF REGENERATIVE COMPOSITE PROCESSES

IEEE TRANSACTIONS ON INFORMATION THEORY 1994年第1期40卷 153-159页

作者： NARAGHIPOUR, M HEGDE, M ARORA, N Department of Electrical and Computer Engineering Louisiana State University Baton Rouge LA USA

Fixed (nonadaptive) and forward adaptive differential pulse code modulation of regenerative composite sources is investigated. In the fixed code, an approximate formula is given for the optimal value of the prediction coefficient. This is then used as an initial guess to optimize the code (predictor and quantizer) through a numerical method. In the forward adaptive scheme, the state of the switch in the composite source is estimated using a MAP sequence estimation algorithm, and the code is then matched to the mode process corresponding to the estimated switch state. The performance of the two systems is evaluated with quantizers of 4, 8, and 16 levels. The results show that the forward adaptive scheme significantly outperforms optimized fixed DPCM in the sense of mean-squared error. Stochastic stability of the code is also established for the fixed DPCM scheme as well as for an adaptive scheme which receives the switch state as side information.

关键词： SOURCE CODING differential pulse code modulation COMPOSITE SOURCES STOCHASTIC STABILITY

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HIGH-QUALITY SUBBAND codeC FOR HDTV TRANSMISSION

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1994年第2期4卷 195-199页

作者： IRIE, K OKUMURA, Y SAKURAI, N KISHIMOTO, R Optical Subscriber Networks Laboratory NTT Transmission Systems Laboratories Yokosuka Kanagawa Japan

High Definition Television (HDTV) is expected to be one of the major services offered in future Broadband Integrated Services Digital Networks (B-ISDN). Transmitting HDTV signals over digital networks requires sophisticated compression techniques to limit bit-rate requirements and to provide high-quality, reliable services to customers. To transmit image signals within a studio and between studios or broadcasting stations, multiple encoding and decoding of signals without visible degradation is required. In this paper, we describe a high-quality HDTV codec that can encode original 1.2 Gb/s HDTV signals at 600 Mb/s. A subband DPCM (differential pulse-code modulation) coding algorithm capable of distortion-free encoding is used. Input signals are decomposed into four bands in the horizontal and vertical directions. A new architecture of perfect reconstructive short-kernel subband filters that reduces subband signal entropy has been adopted. Three bands are coded with adaptive DPCM and one band is coded with PCM. The performance of the codec is evaluated using true video signals. Experimental results show that a very high percentage of samples of component signals can be transmitted distortion free. A Signal-to-Noise Ratio (SNR) of over 45 dB is obtained with signals transmitted after the quantization process. Degradation after nine encoding and decoding processes is only 2 dB in terms of SNR.

关键词： B-ISDN codecs data compression digital communication systems high definition television image coding pulse-code modulation television networks video equipment video signals 1.2 Gbit/s 600 Mbit/s HDTV transmission PCM bit-rate requirements broadban Broadband integrated services digital network differential pulse code modulation Digital communication systems video equipment image coding Television networks Data compression Video signals signals Studios codecs

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LOSSLESS COMPRESSION FOR 3D PET

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IEEE TRANSACTIONS ON NUCLEAR SCIENCE 1994年第6期41卷 2765-2770页

作者： MACQ, B SIBOMANA, M COPPENS, A BOL, A MICHEL, C BAKER, K JONES, B UNIV CATHOLIQUE LOUVAIN PET LABB-1348 LOUVAINBELGIUM CTI PET SYST KNOXVILLETN 37932

A new adaptive scheme is proposed for the lossless compression of positron emission tomography (PET) sinogram data. The algorithm uses an adaptive differential pulse code modulator (ADPCM) followed by a universal variable length coder (UVLC). Contrasting with Lempel-Ziv (LZ), which operates on a whole sinogram, UVLC operates very efficiently on short data blocks. This is a major advantage for real-time implementation. The algorithm is adaptive and codes data after some on-line estimations of the statistics inside each block. Its efficiency is tested when coding dynamic and static scans from two PET scanners and reaches asymptotically the entropy limit for long frames. For very short 3D frames, the new algorithm is twice more efficient than LZ. Since an application specific integrated circuit (ASIC) implementing a similar UVLC scheme is available today, a similar one should be able to sustain PET data lossless compression and decompression at a rate of 27 MBytes/sec. This algorithm is consequently a good candidate for the next generation of lossless compression engine.

关键词： differential pulse code modulation Positron Emission Tomography Systems sinogram algorithms lossless compression Self tuning

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Displaying radiologic images on personal computers. Image storage and compression. Part 2

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Journal of Digital Imaging 1994年第1期7卷 1-1页

作者： Gillespy, Thurman III Rowberg, Alan H. Department of Radiology SB-05 University of Washington Seattle

This is part 2 of our article on image storage and compression, the third article of our series for radiologists and imaging scientists on displaying, manipulating, and analyzing radiologic images on personal computers. Image compression is classified as lossless (nondestructive) or lossy (destructive). Common lossless compression algorithms include variable-length bit codes (Huffman codes and variants), dictionary-based compression (Lempel-Ziv variants), and arithmetic coding. Huffman codes and the Lempel-Ziv-Welch (LZW) algorithm are commonly used for image compression. All of these compression methods are enhanced if the image has been transformed into a differential image based on a differential pulse-code modulation (DPCM) algorithm. The LZW compression after the DPCM image transformation performed the best on our example images, and performed almost as well as the best of the three commercial compression programs tested. Lossy compression techniques are capable of much higher data compression, but reduced image quality and compression artifacts may be noticeable. Lossy compression is comprised of three steps: transformation, quantization, and coding. Two commonly used transformation methods are the discrete cosine transformation and discrete wavelet transformation. In both methods, most of the image information is contained in a relatively few of the transformation coefficients. The quantization step reduces many of the lower order coefficients to 0, which greatly improves the efficiency of the coding (compression) step. In fractal-based image compression, image patterns are stored as equations that can be reconstructed at different levels of resolution.

关键词： differential pulse code modulation discrete cosine transformation discrete wavelet transformation fractal compression Huffman codes image compression Lempel-Ziv-Welch compression personal computer tagged interchange file format

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Interplay Betweeen Recursive System Identification and Adaptive Filtering in Communication Systems

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IFAC Proceedings Volumes 1994年第8期27卷 13-24页

作者： C. Richard Johnson School of Electrical Engineering Cornell University Ithaca NY 14853 USA

Three successful applications of adaptive filtering in communications systems (network echo cancellation, differential pulse code modulation, and linear channel equalization) emerged concurrently just over 25 years ago. This paper surveys these topics with an emphasis on links with the work of recursive system identification experts.

关键词： Adaptive filtering recursive identification adaptive control network echo cancellation differential pulse code modulation linear equalization

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Progressive image transmission by segmentation coding

Progressive image transmission by segmentation coding

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Canadian Conference on Electrical and Computer Engineering (CCECE)

作者： Caron Rivest Department of Electrical Engineering University of Ottawa Ottawa ONT Canada

A coding algorithm is presented for progressive transmission of gray-tone images. The approach is motivated by the desire to retain edge information at low bit rates. A segmentation is first performed using the watershed algorithm to yield an oversegmented mosaic image that is successively decimated. The region contours are chain encoded and transmitted in reverse order, while the lowpass information is coded using DPCM.< >

关键词： Image communication Image segmentation Image coding Image edge analysis differential pulse code modulation

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Cell voice transport considerations for ATM

Cell voice transport considerations for ATM

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Canadian Conference on Electrical and Computer Engineering (CCECE)

作者： Gedeon Narayanan Vreugdenhil Magellan Networks Bell Northern Research Limited Canada

This paper discusses the cell transport characteristics for a viable ATM voice implementation. A system approach to cell voice, both backbone switching and access, is considered. Bandwidth utilization opportunities, i... 详细信息

关键词： Speech processing Asynchronous transfer mode Speech communication Digital communication differential pulse code modulation Echo suppression

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ADAPTIVE CHANNEL ERROR PROTECTION OF SUBBAND ENcodeD IMAGES

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IEEE TRANSACTIONS ON COMMUNICATIONS 1993年第3期41卷 454-459页

作者： WESTERINK, PH WEBER, JH BOEKEE, DE LIMPERS, JW DELFT UNIV TECHNOL DEPT ELECT ENGNINFORMAT THEORY GRP2600 GA DELFTNETHERLANDS PTT RES 2260 AK LEIDSCHENDAMNETHERLANDS

This paper deals with the channel error protection of images that are encoded using subband coding. In this scheme the low-pass subband is encoded using DPCM and the other subbands are encoded using a scalar quantizer. The quantizers are all Lloyd-Max quantizers, where the representation levels have fixed length codewords. First, by considering only single errors in each codeword, a channel error distortion measure is derived for each quantizer, that is, for each subband. codewords will be assigned to the quantizer representation levels, yielding a low value of the distortion measure. Next, sets S(ij) will be formed consisting of the jth bit from subband i. Each set S(ij) will be assigned a particular BCH code C(ij). An algorithm will be derived that optimally assigns BCH codes C(ij) to each set S(ij), based on a channel error distortion measure for the entire image. The protection scheme can be seen to be adaptive, because each set of bits within each subband can be assigned a different error protection code. Examples will show the favorable approach over assigning equal error protection codes to each set of bits. It is shown that in the case of a channel error probability of 10(-3) in this manner only a 5 to 10% extra number of bits is needed for an adequate channel error protection of a subband encoded image.

关键词： Distortion measurement subband coding differential pulse code modulation subband image coding quantizer Error probability error protection Self tuning

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LOW-COMPLEXITY SUBBAND ENCODING FOR HDTV IMAGES

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1993年第1期11卷 77-87页

作者： COPPISETTI, N KWATRA, SC ALASMARI, AK KING SAUD UNIV DEPT ELECT ENGNRIYADH 11421SAUDI ARABIA

The transmission of high-definition television (HDTV) signals on available digital networks and satellites requires the adoption of sophisticated compression techniques to limit the bit rate requirements and to provide high-quality and reliable service to customers. For processing and transmission of image signals, a low-complexity coded without visible degradation is desired. In this paper, a low-complexity intraframe subband image coding algorithm is developed. The low band is DPCM encoded and the high bands are PCM encoded. An efficient entropy coder is designed which reduces the overall bit rate significantly. It is shown that high-quality HDTV images can be obtained at as low a bit rate as 45 Mb/s or less with a very low-complexity encoder. For dividing the image into subbands, a new class of quadrature mirror filters (QMF's) called generalized quadrature mirror filters (GQMF's) are used for filtering. Performance is also evaluated by using short kernel filters (SKF's), which are easy to implement and require very few computations.

关键词： differential pulse code modulation ENcodeR high-frequency band Image communication systems subband Quadrature mirror filters satellites

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OVERVIEW AND PERFORMANCE OF CCITT/ANSI EMBEDDED ADPCM ALGORITHMS

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IEEE TRANSACTIONS ON COMMUNICATIONS 1993年第2期41卷 391-399页

作者： SHERIF, MH BOWKER, DO BERTOCCI, G ORFORD, BA MARIANO, GA AT&T BELL LABS VOICE QUAL ASSESSMENT GRPTECH STAFFHOLMDELNJ 07733 AT&T BELL LABS DEPT DIGITAL TECHHOLMDELNJ 07733

Embedded adaptive differential pulse coded modulation (ADPCM) algorithms quantize the difference between the input signal and the estimated signal into core bits and enhancement bits. This feature gives them an advantage over nonembedded algorithms because they allow an intermediate node to drop the enhancement bits without having to exchange control messages with the transmitting end. CCITT Recommendation G.727 describes embedded ADPCM encoding algorithms with 5, 4, 3, and 2 core bits;it is virtually identical to the corresponding ANSI standard T1.310. This paper highlights the main features of G.727/T1.310 and presents results on its performance. A formal subjective evaluation of the speech performance of embedded ADPCM algorithms indicates that a midrise quantizer provides better voice transmission performance than its midtread counterpart when two core bits are used. The subjective data also show that the performance of the 40 kb/s midrise ADPCM algorithm with two feedback bits is indistinguishable from that of 64 kb/s pulse code modulation (PCM) for up to four tandem encodings. Embedded algorithms are therefore recommended for flexible congestion control of integrated traffic in multinode networks.

关键词： algorithms differential pulse code modulation embedding input signal

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