1,513 research outputs found

    Study and simulation of low rate video coding schemes

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    The semiannual report is included. Topics covered include communication, information science, data compression, remote sensing, color mapped images, robust coding scheme for packet video, recursively indexed differential pulse code modulation, image compression technique for use on token ring networks, and joint source/channel coder design

    Implementation issues in source coding

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    An edge preserving image coding scheme which can be operated in both a lossy and a lossless manner was developed. The technique is an extension of the lossless encoding algorithm developed for the Mars observer spectral data. It can also be viewed as a modification of the DPCM algorithm. A packet video simulator was also developed from an existing modified packet network simulator. The coding scheme for this system is a modification of the mixture block coding (MBC) scheme described in the last report. Coding algorithms for packet video were also investigated

    A multiresolution two-layer video codec for networking applications

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    We propose an improved multiresolution two-layer video codec that can operate at a base layer of 64 kbps and a variable bit rate second layer (VBR). The basic idea is to use a multiresolution technique to reduce the original CIF format video to the QCIF format. The low-resolution video is then encoded with an improved H.261 codec. To reduce the bit rate of the second layer, the residuals are encoded with the discrete cosine transform (DCT) using perceptually weighted quantization step sizes. Simulation results show that the Miss America sequence can be transmitted at 64 kbps in the CIF format with a reasonably good picture quality. For a good picture quality, the second layer would typically require 190 kbps.published_or_final_versio

    Mixture block coding with progressive transmission in packet video. Appendix 1: Item 2

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    Video transmission will become an important part of future multimedia communication because of dramatically increasing user demand for video, and rapid evolution of coding algorithm and VLSI technology. Video transmission will be part of the broadband-integrated services digital network (B-ISDN). Asynchronous transfer mode (ATM) is a viable candidate for implementation of B-ISDN due to its inherent flexibility, service independency, and high performance. According to the characteristics of ATM, the information has to be coded into discrete cells which travel independently in the packet switching network. A practical realization of an ATM video codec called Mixture Block Coding with Progressive Transmission (MBCPT) is presented. This variable bit rate coding algorithm shows how a constant quality performance can be obtained according to user demand. Interactions between codec and network are emphasized including packetization, service synchronization, flow control, and error recovery. Finally, some simulation results based on MBCPT coding with error recovery are presented

    Summative Stereoscopic Image Compression using Arithmetic Coding

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    Image compression targets at plummeting the amount of bits required for image representation for save storage space and speed up the transmission over network. The reduction of size helps to store more images in the disk and take less transfer time in the data network. Stereoscopic image refers to a three dimensional (3D) image that is perceived by the human brain as the transformation of two images that is being sent to the left and right human eyes with distinct phases. However, storing of these images takes twice space than a single image and hence the motivation for this novel approach called Summative Stereoscopic Image Compression using Arithmetic Coding (S2ICAC) where the difference and average of these stereo pair images are calculated, quantized in the case of lossy approach and unquantized in the case of lossless approach, and arithmetic coding is applied. The experimental result analysis indicates that the proposed method achieves high compression ratio and high PSNR value. The proposed method is also compared with JPEG 2000 Position Based Coding Scheme(JPEG 2000 PBCS) and Stereoscopic Image Compression using Huffman Coding (SICHC). From the experimental analysis, it is observed that S2ICAC outperforms JPEG 2000 PBCS as well as SICHC

    Hybrid FDMA/CDMA wireless ATM and subband image coding.

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    by Yeung Chi Kit.Thesis (M.Phil.)--Chinese University of Hong Kong, 1996.Includes bibliographical references (leaves 89-91).Chapter I --- Hybrid FDMA/CDMA Wireless ATM --- p.1Chapter 1 --- Introduction --- p.2Chapter 1.1 --- Motivation --- p.2Chapter 1.2 --- Thesis Organization (PART I) --- p.5Chapter 2 --- Fundamentals --- p.6Chapter 2.1 --- Spread Spectrum --- p.6Chapter 2.1.1 --- Direct Sequence (DS) CDMA --- p.6Chapter 2.1.2 --- Frequency Hopping (FH) CDMA --- p.8Chapter 2.1.3 --- Time Hopping (TH) CDMA --- p.8Chapter 2.1.4 --- MC-CDMA (Multicarrier-CDMA) --- p.9Chapter 2.2 --- Asynchronous Transfer Mode (ATM) --- p.10Chapter 3 --- System Model --- p.12Chapter 4 --- System Capacity --- p.16Chapter 4.0.1 --- One Homogeneous User Population --- p.16Chapter 4.0.2 --- Two Homogeneous User Populations --- p.18Chapter 5 --- Conclusion --- p.24Chapter II --- Subband Image Coding --- p.28Chapter 6 --- Introduction --- p.29Chapter 6.1 --- Motivation --- p.29Chapter 6.2 --- Thesis Organization (PART II) --- p.31Chapter 7 --- Fundamentals --- p.33Chapter 7.1 --- Image Fidelity Criteria --- p.33Chapter 7.1.1 --- Numerical (Quantitative) Measures --- p.34Chapter 7.1.2 --- Perceptual (Subjective) Measure --- p.34Chapter 8 --- Wavelet Transform --- p.36Chapter 8.1 --- Wavelet Theory --- p.37Chapter 8.2 --- Multiresolution Analysis --- p.39Chapter 8.3 --- Quality Criteria for Wavelets --- p.42Chapter 8.4 --- Criteria for filters...................´ب --- p.43Chapter 8.5 --- Orthogonal Discrete Wavelet Transform --- p.45Chapter 8.6 --- Biorthogonal Discrete Wavelet Transform --- p.47Chapter 8.7 --- Wavelet Packets Transform --- p.48Chapter 8.8 --- Appendix --- p.50Chapter 8.8.1 --- QMF & CQF --- p.50Chapter 8.8.2 --- Examples of Orthogonal Filters --- p.53Chapter 8.8.3 --- Examples of Biorthogonal Filters --- p.53Chapter 9 --- Transform Coding and Compression --- p.55Chapter 9.1 --- Transformation Techniques --- p.56Chapter 9.2 --- Quantization --- p.57Chapter 9.2.1 --- Scalar Quantization --- p.57Chapter 9.2.2 --- Llyod-Max Quantization --- p.59Chapter 9.2.3 --- Vector Quantization --- p.59Chapter 9.2.4 --- Successive Approximation Entropy-Coded Quantization --- p.60Chapter 9.3 --- Entropy Coding --- p.61Chapter 9.3.1 --- Huffman Coding --- p.61Chapter 9.3.2 --- Arithmetic Coding --- p.62Chapter 9.3.3 --- Dictionary Based Coding --- p.64Chapter 9.3.4 --- Run Length Coding --- p.65Chapter 9.3.5 --- Example --- p.65Chapter 10 --- Embedded Zerotree Algorithm --- p.69Chapter 10.1 --- Significance Map Encoding --- p.70Chapter 10.2 --- Successive Approximation Entropy Coded Quantization --- p.72Chapter 10.3 --- Example --- p.74Chapter 10.4 --- Comments on EZW --- p.77Chapter 11 --- Residue Coding Using Embedded Zerotree Algorithm --- p.79Chapter 11.1 --- Residue Coding --- p.80Chapter 11.2 --- Results --- p.81Chapter 12 --- Conclusion --- p.8

    Distributed multimedia systems

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    A distributed multimedia system (DMS) is an integrated communication, computing, and information system that enables the processing, management, delivery, and presentation of synchronized multimedia information with quality-of-service guarantees. Multimedia information may include discrete media data, such as text, data, and images, and continuous media data, such as video and audio. Such a system enhances human communications by exploiting both visual and aural senses and provides the ultimate flexibility in work and entertainment, allowing one to collaborate with remote participants, view movies on demand, access on-line digital libraries from the desktop, and so forth. In this paper, we present a technical survey of a DMS. We give an overview of distributed multimedia systems, examine the fundamental concept of digital media, identify the applications, and survey the important enabling technologies.published_or_final_versio

    An investigation into the requirements for an efficient image transmission system over an ATM network

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    This thesis looks into the problems arising in an image transmission system when transmitting over an A TM network. Two main areas were investigated: (i) an alternative coding technique to reduce the bit rate required; and (ii) concealment of errors due to cell loss, with emphasis on processing in the transform domain of DCT-based images. [Continues.
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