检索结果-内蒙古大学图书馆

Exploration and Exploitation of Reference Frames in distributed video coding

IEEE SIGNAL PROCESSING LETTERS 2012年第7期19卷 411-414页

作者： Zheng, Min Ali, Falah H. Univ Sussex Sch Engn & Informat Commun Res Grp Brighton BN1 9QT E Sussex England

This letter investigates the impact of reference frames in distributed video coding (DVC) on the Rate-Distortion (RD) performance and reveals that reference frames have the potential to be better side information (SI) than the extensively used interpolated frames. Based on this investigation, we also propose a motion range prediction (MRP) method to exploit reference frames and precisely guide the statistical motion learning process. Extensive simulation results show that choosing reference frames as SI performs competitively, and sometimes even better than interpolated frames. Furthermore, the proposed MRP method is shown to significantly reduce the decoding complexity without degrading any RD performance.

关键词： distributed video coding motion learning reference frames side information

来源：评论

学校读者我要写书评

暂无评论

Rate estimate for regular LDPCA codec in distributed video coding

引用

The Journal of China Universities of Posts and Telecommunications 2012年第1期19卷 50-54页

作者： MING Yang-yang YANG Bo QUAN Zi-Yi MEN Ai-dong School of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

Accumulated low density parity check （LDPCA） codec is proposed for DISCOVER project in distributed video coding （DVC）, which offers flexible coding rate. Although it can use feedback channel to adapt the rate to the correlation of the video, but in real applications, using feedback channel can not always be possible. To solve this problem, some researchers proposed estimating the code rate at the encoder but the performance was not very good. Based on their researches, this paper considers the impact of convergence rate for iteration on rate estimate, which can be calculated using its check matrix. As a pilot study, this paper pays attention to the regular LDPCA codec. At the same time, it considers the impact of deviation in the estimated crossover probability, which gives some constraints to rate estimate. In the experiment, the proposed algorithm can improve the rate-distortion performance by up to 1 dB-1.2 dB.

关键词： LDPCA distributed video coding rate estimate regular LDPCA codec crossover probability deviation

来源：评论

学校读者我要写书评

暂无评论

Transform domain distributed video coding with spatial correlations

引用

MULTIMEDIA TOOLS AND APPLICATIONS 2010年第3期48卷 369-379页

作者： Badem, M. B. Fernando, W. A. C. Kondoz, A. M. Univ Surrey Ctr Commun Syst Res Guildford GU2 7XH Surrey England

distributed video coding is a new coding technique which has been evolving very fast recently. However the rate distortion performances of current solutions are below the expectations especially for high motion sequences even at a group of picture (GOP) size of 2. Main reason of this problem is the temporal prediction of the Wyner-Ziv (WZ) frames at the decoder. In this paper we propose a novel transform domain DVC codec architecture which splits each frame into two sub-frames and they are encoded separately as key sub-frame and WZ sub-frame. Pixel interpolation or median prediction techniques are utilized to generate the side information at the decoder. Simulation results show that a significant rate distortion improvement can be obtained with the proposed algorithm over the current DVC solutions.

关键词： distributed video coding Wyner-Ziv coding

来源：评论

学校读者我要写书评

暂无评论

Practical distributed video coding in packet lossy channels

引用

OPTICAL ENGINEERING 2013年第7期52卷

作者： Qing, Linbo Masala, Enrico He, Xiaohai Sichuan Univ Coll Elect & Informat Engn Chengdu 610065 Peoples R China Politecn Torino Control & Comp Engn Dept I-10129 Turin Italy

Improving error resilience of video communications over packet lossy channels is an important and tough task. We present a framework to optimize the quality of video communications based on distributed video coding (DVC) in practical packet lossy network scenarios. The peculiar characteristics of DVC indeed require a number of adaptations to take full advantage of its intrinsic robustness when dealing with data losses of typical real packet networks. This work proposes a new packetization scheme, an investigation of the best error-correcting codes to use in a noisy environment, a practical rate-allocation mechanism, which minimizes decoder feedback, and an improved side-information generation and reconstruction function. Performance comparisons are presented with respect to a conventional packet video communication using H.264/advanced video coding (AVC). Although currently the H.264/AVC rate-distortion performance in case of no loss is better than state-of-the-art DVC schemes, under practical packet lossy conditions, the proposed techniques provide better performance with respect to an H.264/AVC-based system, especially at high packet loss rates. Thus the error resilience of the proposed DVC scheme is superior to the one provided by H.264/AVC, especially in the case of transmission over packet lossy networks. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： distributed video coding Wyner-Ziv packetization packet lossy networks side information

来源：评论

学校读者我要写书评

暂无评论

distributed video coding using JPEG 2000 coding scheme

引用

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2007年第3期E90A卷 581-589页

作者： Tonomura, Yoshihide Nakachi, Takayuki Fujii, Tetsuro NTT Corp NTT Networked Innovat Labs Yokosuka Kanagawa 2390847 Japan

distributed video coding (DVC), based on the theorems proposed by Slepian-Wolf and Wyner-Ziv, is attracting attention as a new paradigm for video compression. Some of the DVC systems use intraframe compression based on discrete cosine transform (DCT). Unfortunately, conventional DVC systems have low affinity with DCT. In this paper, we propose a wavelet-based DVC scheme that utilizs current JPEG 2000 standard. Accordingly, the scheme has scalability with regard to resolution and quality. In addition, we propose two methods to increase the coding gain of the new DVC scheme. One is the introduction of a Gray code, and the other method involves optimum quantization. An interesting point is that though our proposed method uses Gray code, it still achieves quality scalability. Tests confirmed that the PSNR is increased about 5 [dB] by the two methods, and the PSNR of the new scheme (with methods) is about 1.5-3 [dB] higher than that of conventional JPEG 2000.

关键词： distributed video coding JPEG 2000 wavelet transform LDPC mobile camera sensor network

来源：评论

学校读者我要写书评

暂无评论

A flexible side information generation framework for distributed video coding

引用

MULTIMEDIA TOOLS AND APPLICATIONS 2010年第3期48卷 381-409页

作者： Ascenso, Joao Brites, Catarina Pereira, Fernando Inst Super Engn Lisboa Inst Telecomunicacoes P-1950062 Lisbon Portugal Univ Tecn Lisboa Inst Telecomunicacoes Inst Super Tecn P-1049001 Lisbon Portugal

One of the most efficient approaches to generate the side information (SI) in distributed video codecs is through motion compensated frame interpolation where the current frame is estimated based on past and future reference frames. However, this approach leads to significant spatial and temporal variations in the correlation noise between the source at the encoder and the SI at the decoder. In such scenario, it would be useful to design an architecture where the SI can be more robustly generated at the block level, avoiding the creation of SI frame regions with lower correlation, largely responsible for some coding efficiency losses. In this paper, a flexible framework to generate SI at the block level in two modes is presented: while the first mode corresponds to a motion compensated interpolation (MCI) technique, the second mode corresponds to a motion compensated quality enhancement (MCQE) technique where a low quality Intra block sent by the encoder is used to generate the SI by doing motion estimation with the help of the reference frames. The novel MCQE mode can be overall advantageous from the rate-distortion point of view, even if some rate has to be invested in the low quality Intra coding blocks, for blocks where the MCI produces SI with lower correlation. The overall solution is evaluated in terms of RD performance with improvements up to 2 dB, especially for high motion video sequences and long Group of Pictures (GOP) sizes.

关键词： distributed video coding Wyner-Ziv video coding Side information Intra coding mode Quality enhancement

来源：评论

学校读者我要写书评

暂无评论

Two-Dimensional Iterative Source-Channel Decoding for distributed video coding

引用

IEEE COMMUNICATIONS LETTERS 2014年第1期18卷 90-93页

作者： Huo, Yongkai Wang, Tao Maunder, Rob Hanzo, Lajos Univ Southampton Southampton SO9 5NH Hants England

Motivated by the Joint Source-Channel Decoding (JSCD) principle of exploiting the source redundancy, in this treatise we study the application of iterative source-channel decoding (ISCD) conceived for distributed video coding (DVC), where the video signal is modelled by our Iterative Horizontal-Vertical Scanline Model (IHVSM) relying on a first-order Markov process. The IHVSM technique is combined with the classic forward error correction (FEC) codecs employed in the state-of-the-art DVC systems for the sake of reducing the bitrate. Our simulation results show that up to 21.5% bitrate reductions are achieved by employing the proposed ISCD technique in a DVC scheme. Alternatively, a peak signal-to-noise ratio (PSNR) gain of 2.2 dB is achieved at a bitrate of 4.5 Mbps when considering the Foreman sequence.

关键词： Iterative source-channel decoding distributed video coding

来源：评论

学校读者我要写书评

暂无评论

Overlapped Block Motion Estimation and Probabilistic Compensation with Application in distributed video coding

引用

IEEE SIGNAL PROCESSING LETTERS 2009年第9期16卷 743-746页

作者： Deligiannis, Nikos Munteanu, Adrian Clerckx, Tom Cornelis, Jan Schelkens, Peter Vrije Univ Brussels Elect & Informat Dept ETRO Interdisciplinary Inst Broadband Technol IBBT B-1050 Brussels Belgium

It has been recently demonstrated that, in distributed video coding (DVC) side-information dependent modeling of the correlation channel brings significant performance gains over side-information independent assumptions. In this letter, we present a novel technique enabling advanced side-information dependent estimation of the correlation channel at the decoder starting from a very coarse knowledge of it. The proposed technique triggers the design of a spatial-domain DVC codec which enables the suppression of the feedback channel. Experimental results show that the proposed codec achieves similar performance compared to the state-of-the-art in transform-domain Wyner-Ziv video coding while still operating at a fraction of its encoding complexity.

关键词： Correlation channel distributed video coding feedback channel suppression overlapped block motion estimation probabilistic reconstruction

来源：评论

学校读者我要写书评

暂无评论

Rate-distortion analysis of motion-compensated interpolation at the decoder in distributed video coding

引用

IEEE SIGNAL PROCESSING LETTERS 2007年第9期14卷 625-628页

作者： Tagliasacchi, Marco Frigerio, Laura Tubaro, Stefano Politecn Milan Dipartimento Elettron & Informaz I-20133 Milan Italy

This letter analyzes the coding efficiency of distributed video coding (DVC) schemes that perform motion-compensated interpolation at the decoder. The decoder has access only to the key frames, when generating the side information for intermediate frames. Therefore, the true motion field necessary for this operation is not directly available, and the motion vectors must be estimated at the decoder side, thus introducing displacement estimation errors. The accuracy of the motion-compensated interpolation at the decoder depends on several factors: 1) the overall motion complexity;2) the temporal coherence of the motion field;and 3) the temporal distance between successive key frames. Adopting a state-space model and a Kalman filtering framework, we obtain an estimate of the displacement error variance. This is used to determine the rate-distortion function of the overall coding scheme, that takes into account both intra-coded key frames and DVC-coded frames. The proposed model shows that motion-compensated interpolation is unable to achieve the coding efficiency of conventional motion-compensated predictive coding. In addition, the model provides a good estimate of the group of pictures size that optimizes the coding efficiency. Experimental results on real video sequences validate the results of the proposed model.

关键词： distributed video coding motion analysis video coding

来源：评论

学校读者我要写书评

暂无评论

Maximum likelihood motion compensation for distributed video coding

引用

INTEGRATED COMPUTER-AIDED ENGINEERING 2012年第3期19卷 215-227页

作者： Verbist, Frederik Deligiannis, Nikos Jacobs, Marc Barbarien, Joeri Schelkens, Peter Munteanu, Adrian Vrije Univ Brussel Dept Elect & Informat B-1050 Brussels Belgium Interdisciplinary Inst Broadband Technol Dept Future Media & Imaging Ghent Belgium

Aspiring to provide robust low-complexity encoding for video, this work presents a hash-based transform domain distributed video codec, featuring a novel maximum likelihood motion compensation technique to generate high quality side information at the decoder. A simple hash is employed to perform overlapped block motion estimation at the decoder, which produces a set of temporal predictors on a pixel basis. For every pixel position, maximum likelihood motion compensation, based on an online estimate of the conditional dependencies between the temporal predictors and the original frame, combines the cluster of temporal predictors into a single value to serve as decoder-generated side information. Efficient low-density parity-check accumulate channel codes refine the side information in the transform domain. Experimental results demonstrate that the proposed system advances over our previous hash-based distributed video coding architectures, delivering state-of-the-art distributed coding performance, in particular for sequences organized in large groups of pictures or containing highly irregular motion. Notwithstanding the presence of a hash, the presented distributed video codec successfully maintains low encoder complexity.

关键词： distributed video coding Wyner-Ziv video coding side information generation hash-based motion estimation motion compensation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：