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Conference on Visual Communications and Image Processing 2002

作者： Hsiang, ST Woods, JW Rensselaer Polytech Inst Ctr Image Proc Res Troy NY 12180 USA

ISBN: (纸本)0819444111

Former research on perceptual image coding was mainly developed in the traditional sequential coding frame-work, where the codestream is neither rate nor resolution scalable. In this paper, our earlier embedded subband/wavelet image coding algorithm EZBC is further developed for highly scalable image coding applications. Special attention is given to perceptual image coding under varying viewing/display conditions - a common situation in typical scalable coding application environments. Unlike the conventional perceptual image coding approach, all the perceptually coded images (individually targeted at particular viewing conditions) are decoded from a single compressed bitstream file. The experimental results show the bitrate savings by the proposed algorithm are significant, particularly for coding of high-definition (HD) images.

关键词： perceptual coding wavelet image compression scalable coding set-partitioning EZBC

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Coarse scale cost-utility approach for efficient unequal loss protection

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2002年第8期17卷 587-596页

作者： Chen, YS Wang, GP Dong, SH Peking Univ HCI & Multimedia Lab Dept Comp Sci Beijing 100871 Peoples R China

The framework of unequal loss protection (ULP) is an attractive method for the protection of the embedded image or video data source generated by a scalable coding scheme in the environment of packet switched networks. In this paper, an efficient preprocessing algorithm is presented based on the idea of the coarse scale cost-utility (CSCU) working curve. The experimental results show that the CSCU method significantly improves the efficiency of the ULP assignment framework with substantial memory and computation savings. We believe that the idea of coarse scale operation can also be successfully used in many other applications. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： scalable coding unequal loss protection forward error correcting multiple description coding

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Spatial scalable video coding using a combined subband-DCT approach

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2000年第7期10卷 1080-1087页

作者： Benzler, U Univ Hannover Inst Theoret Nachrichtentech & Informat Verarbeit Hannover Germany

A combined subband-DCT approach for spatial scalable video coding is presented. The high-resolution input signal is decomposed into four spatial subband signals. The low-frequency subband is used as the low-resolution signal and is separately coded in the base-layer bitstream, and the high-frequency subband signals are coded in the enhancement-layer bitstream, The low-resolution signal is reconstructed from the base-layer bitstream and the high-resolution signal is reconstructed using both the base- and the enhancement-layer bitstream, Similar to MPEG, DCT-based hybrid coding techniques are applied for the coding of the subband signals, but an improved motion-compensated prediction is used for the low-resolution signal. Additionally, SNR scalability is introduced to allow a flexible bit allocation for the base and the enhancement layer. Experimental results at a bit rate of 6 Mbit/s show that the reference coder MPEG-4 spatial scalable profile (SSP) leads to a loss of more than 2.2-dB peak signal-to-noise ratio (PSNR) compared with nonscalable MPEG-2 coding at the same bit rate, whereas the proposed combined subband-DCT scheme is able to achieve a decrease of less than 0.4 dB in PSNR.

关键词： scalable coding spatial scalability subband coding video coding

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Efficient video coding with hybrid spatial and fine-grain SNR scalabilities

Efficient video coding with hybrid spatial and fine-grain SN...

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Conference on Visual Communications and Image Processing 2002

作者： Yan, R Wu, F Li, SP Tao, R Wang, Y Beijing Inst Technol Dept Elect Engn Beijing 100081 Peoples R China

ISBN: (纸本)0819444111

A flexible and effective macroblock-based framework for hybrid spatial and fine-grain SNR scalable video coding is proposed in this paper. In the proposed framework, the base layer is of low resolution and is generally encoded at low bit rates with traditional prediction based coding schemes. Two enhancement layers, i.e., the low-resolution enhancement layer and the high-resolution enhancement layer, are generated to improve the video quality of the low-resolution base layer and evolve smoothly from low resolution to high resolution video with increasingly better quality, respectively. Since bit plane coding and drifting control techniques are applied to the two enhancement layers, each enhancement bitstream is fine-grain scalable and can be arbitrarily truncated to fit in the available channel bandwidth. In order to improve the coding efficiency and reduce the drifting errors at the high-resolution enhancement layer, five macroblock coding modes with different forms of motion compensation and reconstruction, are proposed in this paper. Furthermore, a mode decision algorithm is developed to select the appropriate coding mode for each macroblock at the high-resolution enhancement layer. Compared with the traditional spatial scalable coding scheme, the proposed framework not only provides the spatial scalability but also provides the fine granularity quality scalability at the same resolution.

关键词： layered coding scalable coding spatial scalable coding SNR scalable coding macroblock coding mode fine granularity scalable (FGS) progressive fine granularity scalable (PFGS)

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Performance of the color set partitioning in hierarchical tree scheme (CSPIHT) in video coding

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CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2001年第2期20卷 253-270页

作者： Kassim, AA Siong, LW Natl Univ Singapore Dept Elect & Comp Engn Singapore 119260 Singapore

This paper describes the implementation of the recently introduced color set partitioning in hierarchical tree (CSPIHT)-based scheme for video coding. The intra- and interframe coding performance of a CSPIHT-based video coder (CVC) is compared against that of the H.263 at bit rates lower than 64 kbit/s. The CVC performs comparably or better than the H.263 at lower bit rates, whereas the H.263 performs better than the CVC at higher bit rates. We identify areas that hamper the performance of the CVC and propose an improved scheme that yields better performance in image and video coding in low bit-rate environments.

关键词： SPIHT CSPIHT scalable coding video coding video compression discrete wavelet transform

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Motion-compensated video compression with reduced complexity encoding for remote transmission

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2001年第7期16卷 627-642页

作者： Creusere, CD New Mexico State Univ Klipsch Sch Elect & Comp Engn Las Cruces NM 88003 USA USN Air Warfare Ctr China Lake CA USA

Efficient operation at very low bit-rates necessitates a complex encoder that can exploit both spatial and temporal redundancy in a video sequence. To reduce the complexity of such an encoder, we introduce here a new form of motion compensation similar to the conventional hybrid DPCM-transform method but where the compensation is performed outside the feedback loop. In addition to reducing encoder complexity, the proposed out-of-loop (OOL) compensation scheme also supports resolution and frame-rate scalability. While the basic idea is conceptually similar to the pan compensation proposed by Taubman and Zakhor, our method continually tracks and updates the image in the feedback loop in the same way as the conventional DPCM coder. Using OOL compensation, we have observed an average encoder speed increase of 33% on a typical CIF-size video sequence compared to the conventional approach with no significant decrease in decoder speed. Furthermore, we have also found that OOL pan compensation significantly improves the rate-distortion performance of the system relative to conventional pan compensation - taken over five different video sequences, the average bit-rate reduction is 9.2% and the average mean-squared error reduction is 29.6%. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： image compression video compression motion compensation low complexity wavelet scalable coding

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Embedded foveation image coding

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2001年第10期10卷 1397-1410页

作者： Wang, Z Bovik, AC Univ Texas Dept Elect & Comp Engn Lab Image & Video Engn Austin TX 78712 USA

The human visual system (HVS) is highly space-variant in sampling, coding, processing, and understanding. The spatial resolution of the HVS is highest around the point of fixation (foveation point) and decreases rapidly with increasing eccentricity. By taking advantage of this fact, it is possible to remove considerable high-frequency information redundancy from the peripheral regions and still reconstruct a perceptually good quality image. Great success has been obtained recently by a class of embedded wavelet image coding algorithms, such as the embedded zerotree wavelet (EZW) and the set partitioning in hierarchical trees (SPIHT) algorithms. Embedded wavelet coding not only provides very good compression performance, but also has the property that the bitstream can be truncated at any point and still be decoded to recreate a reasonably good quality image. In this paper, we propose an embedded foveation image coding (EFIC) algorithm, which orders the encoded bitstream to optimize foveated visual quality at arbitrary bit-rates. A foveation-based image quality metric, namely, foveated wavelet image quality index (FWQI), plays an important role in the EFIC system. We also developed a modified SPIHT algorithm to improve the coding efficiency. Experiments show that EFIC integrates foveation filtering with foveated image coding and demonstrates very good coding performance and scalability in terms of foveated image quality measurement.

关键词： embedded coding foveated image coding foveation foveation filtering human visual system (HVS) image coding image quality measurement progressive transmission scalable coding wavelet

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scalable, error-resilient, and high-performance video communications in mobile wireless environments

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2001年第7期11卷 833-847页

作者： Vass, J Zhuang, S Zhuang, XH Eyeball Networks Inc Vancouver BC V7T 1A2 Canada Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA Univ Missouri Dept Comp Engn & Comp Sci Columbia MO 65211 USA

A novel mobile communications system is proposed in the paper, which provides not only effective but also efficient video access for mobile users when communicating over low-bandwidth error-prone wireless links, The middleware implemented by a mobile proxy server at the mobile support station is designed for the seamless integration of mobile users with video servers, so the specific details of the underlying protocols and source/channel coding techniques are hidden to both the video server and mobile client. Based on the concept of application-level framing, the application (video codec in our case) plays a significant role in network communications that most of functionalities of the system are implemented as part of the application, As such, at the application layer, adaptive source- and channel-coding techniques are developed to jointly provide the user with the highest possible video quality, For efficient source coding, our high-performance low-complexity video-coding algorithm called a 3-D significance-linked connected component analysis (3D-SLCCA) is chosen, Due to its high robustness against channel-error propagation, 3D-SLCCA is well suited for wireless environments. For error-resilient channel coding, a multilayer transmission error-control mechanism is developed, Since there is no additional requirement imposed on either the mobile client or the video server, mobile users interact with the server in exactly the same way as stationary users, Extensive computer experiments demonstrate the effectiveness of the proposed system.

关键词： error-resilient coding joint source-channel coding mobile communications proxy server scalable coding SLCCA video coding

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Modulation frequency and efficient audio coding

Modulation frequency and efficient audio coding

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Conference on Advanced Signal Processing Algorithms, Architectures, and Implementations XI

作者： Atlas, LE Vinton, MS Univ Washington Dept Elect Engn Seattle WA 98195 USA

ISBN: (纸本)0819441880

The concept of "modulation frequency" is shown to be a valuable insight into time-frequency transforms for audio coding. A two-dimensional transform, where the second dimension approximately decomposes the audio signal into modulation frequencies, is proposed. This transform, when applied to audio coding, provides high quality at low data rates and adapt gracefully to changes in available bandwidth. It is inherently scalable, meaning that channel conditions can be matched without the need for additional computation. Moreover, it is compact: in subjective tests our algorithm, coded at 32kilobits/seconds/channel, outperformed MPEG-l Layer 3 (MP3) coded at 56 kilobits/seconds/channel (both at 44.1 kHz). This potentially useful result motivates the need for further insight into the definition and analysis of modulation frequency. We thus define modulation frequency for a simple narrowband signal, propose a general bilinear framework for detection, and then propose a minimal set of conditions to extend this definition to broadband signals such as audio.

关键词： time-frequency analysis modulation frequency audio coding audio compression scalable coding

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MPEG-2 spatial scalable coding and transport stream error concealment for satellite TV broadcasting using Ka-band

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IEEE TRANSACTIONS ON BROADCASTING 1998年第2期44卷 233-242页

作者： Hsu, YF Chen, YC Huang, CJ Sun, MJ Natl Tsing Hua Univ Dept Elect Engn Hsinchu Taiwan

In this paper, an effective MPEG-2 spatial scalable video codec is designed, and error concealment technique of associated transport stream is proposed. The spatial scalability can provide robust error resilience for Ka-band rain attenuation, as well as the co-existence of HDTV and SDTV systems. In MPEG-2, the spatial scalable encoder combines both spatial and temporal predictions. This paper proposes a near optimal spatial-temporal weighting analyzer to properly assign cv eights Simulation shows that the proposed spatial scalable codec structure outperforms the performance of the other MPEG-2 codecs for TV broadcasting in Ka band using satellites. We also propose a suitable error protection and concealment method for MPEG-2 transport stream. With the combination of scalable coding and error protection systems, the proposed system will achieve high link availability.

关键词： digital television direct broadcasting by satellite error correction microwave propagation television broadcasting television interference television standards tropospheric electromagnetic wave propagation video codecs 18 to 30 GHz HDTV Ka-band MPEG-2 sp microwave propagation television broadcasting codecs tropospheric electromagnetic wave propagation error protection television interference Television Digital television video codecs transport stream Extremely high frequencies error correction scalable coding television standards

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