检索结果-内蒙古大学图书馆

Conference on Visual Communications and image Processing 2005

作者： Liu, Y Ngan, KN Chinese Univ Hong Kong Dept Elect Engn Shatin Hong Kong Peoples R China

ISBN: (纸本)0819459763

This paper presents an embedded wavelet packet image coding algorithm which is based on context classification and quadtree ordering (CCAQO). To match up well with the quadtree-based embedded coder, a new cost function for the best basis selection is adopted in discrete wavelet packet transform (DWPT). In addition, combined with the structure of the best wavelet packet basis, a complete quadtree representation of wavelet packet coefficients is established to explore the ordering procedure of embedded image coding. Since subband correlation is mainly captured by significance coding, our focus is on significance coding. The significance probability of wavelet coefficient is estimated by convoluting a 9 x 9 FIR filter matrix kernel with the significance states of neighboring coefficients, and then a context classifier based on Lloyd-Max algorithm is used to categorize the wavelet coefficients with the same or similar significance probability into several contexts. The significance state of wavelet coefficient with respect to a given threshold is encoded using adaptive arithmetic coder based on the classified context. Due to the optimal context classifier and the flexible quadtree representation ability of wavelet packet coefficients, the proposed CCAQO embedded image coder offers improvement in subjective and objective quality for texture-rich images and experimental results show that it offers coding performance superior to or comparable to the state-of-the-art image coders.

关键词： embedded image coding wavelet packet best basis context classification quadtree ordering

来源：评论

学校读者我要写书评

暂无评论

A contourlet-based embedded image coding scheme on low bit-rate

引用

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2008年第9期E91D卷 2333-2340页

作者： Song, Haolhao Yu, Songyu Minist Publ Secur Res Inst 3 Shanghai 200031 Peoples R China Shanghai Jiao Tong Univ Inst Image Commun & Informat Proc Shanghai 200240 Peoples R China

Contourlet transform (CT) is a new image representation method, which can efficiently represent contours and textures in images. However, CT is a kind of overcomplete transform with a redundancy factor of 4/3. If it is applied to image compression straightforwardly, the encoding bit-rate may increase to meet a given distortion. This fact baffles the coding community to develop CT-based image compression techniques with satisfactory performance. In this paper, we analyze the distribution of significant contourlet coefficients in different subbands and propose a new contourlet-based embedded image coding (CEIC) scheme on low bit-rate. The well-known wavelet-based embedded image coding (WEIC) algorithms such as EZW, SPIHT and SPECK can be easily integrated into the proposed scheme by constructing a virtual low frequency subband, modifying the coding framework of WEIC algorithms according to the structure of contourlet coefficients, and adopting a high-efficiency significant coefficient scanning scheme for CEIC scheme. The proposed CEIC scheme can provide an embedded bit-stream, which is desirable in heterogeneous networks. Our experiments demonstrate that the proposed scheme can achieve the better compression performance on low bit-rate. Furthermore, thanks to the contourlet adopted in the proposed scheme, more contours and textures in the coded images are preserved to ensure the superior subjective quality.

关键词： embedded image coding contourlet wavelet scanning scheme

来源：评论

学校读者我要写书评

暂无评论

Perceptual embedded image coding using wavelet transforms

Perceptual embedded image coding using wavelet transforms

引用

International Conference on image Processing

作者： Mazzarri, A Leonardi, R UNIV BRESCIA DEASIGNALS & COMMUN LABBRESCIAITALY

ISBN: (纸本)0780331222

We present a modified version of an embedded wavelet coding scheme, first suggested by Shapiro (see IEEE Transactions on Signal Processing, vol.41, no. 12, p.3445-3462, 1993), that improves the performance of the original algorithm in a visual subjective distortion sense. We preserve the features of the original Shapiro's embedded coder. It is possible to choose a fixed target bit rate, as the information needed to represent an image coded at some rate always contains the needed information for the same image coded at lower rates. Therefore, the decoder can cease decoding the bit stream at any point, simulating an image coded at a lower rate corresponding to the truncated bit stream. We also introduce some perceptive improvements by adopting different (more regular) filters with respect to the original QMF pyramid filters proposed by Simoncelli, Hingorani et al. (1987) and used by Shapiro. These filters are synthesized using a "wavelet approach" instead of a "subband approach", and this leads to a better control on their regularity properties, jointly with better perceptual performance.

关键词： bit stream wavelet transforms embedded image coding target bit rate image coding Filters image

来源：评论

学校读者我要写书评

暂无评论

A Filter Banks Design Using a Multi-objective Genetic Algorithm for embedded image coding Scheme

A Filter Banks Design Using a Multi-objective Genetic Algori...

引用

International Symposium on image and Signal Processing and Analysis

作者： A. Boukhobza A. Taleb Ahmed A. Bounoua N. Taleb RCAM Laboratory of research University of Sidi-Bel Abbes LAMIH Laboratory of research University of Valenciennes Valenciennes RCAM Laboratory of research University of Sidi-BelAbbes

ISBN: (纸本)9781424456499

A multi-objective genetic algorithm for the design of biorthogonal filter banks for embedded image coding application is presented. To be effective, the filter bank would satisfy multiple requirements related to such application. Flexibility in the design is introduced by imposing Near Perfect Reconstruction (N-PR) condition instead of entire PR condition as in conventional designs. Especially for embedded coding purposes, the filter banks are designed to be near-orthogonal. This can only be made possible by minimizing the deviation from the orthogonality in the optimization process. The optimization problem is formulated as a constrained multi-objective problem and solved using a constrained Non-dominated sorting genetic algorithm (C-NSGA) by searching solutions that achieve the best compromise between the different objective criteria, these solutions are known as Pareto Optimal Solutions. Experiment results show that our designed filter banks lead to improved performances of image coding compared to those achieved by the 9/7 filter bank of JPEG2000.

关键词： Filter banks embedded image coding Genetic Algorithm (GA) Banks Algorithm design JPEG image coding orthogonality Optimization Procedure multi-objective evolutionary algorithm

来源：评论

学校读者我要写书评

暂无评论

embedded wavelet packet object-based image coding based on context classification and quadtree ordering

引用

SIGNAL PROCESSING-image COMMUNICATION 2006年第2期21卷 143-155页

作者： Liu, Y Ngan, KN Chinese Univ Hong Kong Dept Elect Engn Shatin Hong Kong Peoples R China

In this paper, an object-based embedded image coding algorithm based on context classification and quadtree ordering in wavelet packet domain (OB-CCAQO) is proposed. To match up well with the quadtree-based embedded coder, a new cost function for the best basis selection is adopted in SA-DWPT (shape adaptive discrete wavelet packet transform). The significance probability of wavelet coefficient is estimated by convoluting a 9 x 9 FIR filter matrix kernel with the significance states of neighboring coefficients, and then a context classifier based on Lloyd-Max algorithm is used to categorize the wavelet coefficients with the same or similar significance probability into several contexts. The significance state of wavelet coefficient with respect to a given threshold is encoded using adaptive arithmetic coder based on the classified context. In addition, combined with the structure of the best wavelet packet basis, a complete quadtree representation of wavelet packet coefficients is established to explore the ordering procedure of embedded object-based image coding. Experimental results show that the proposed object-based embedded image coder offers coding performance superior to the popular object-based coders and is also comparable to or better than the state-of-art embedded image coder when applied in the framed-based image coding. (c) 2005 Elsevier B.V. All rights reserved.

关键词： embedded image coding object-based coding best wavelet packet basis significance probability estimation context classification quadtree ordering

来源：评论

学校读者我要写书评

暂无评论

A new, enhanced EZW image codec with subband classification

引用

MULTIMEDIA SYSTEMS 2022年第1期28卷 1-19页

作者： Brahimi, Tahar Khelifi, Fouad Laouir, Farid Kacha, Abdellah Univ Mohammed Seddik Benyahia Jijel Dept Elect L2EI Res Lab BP 98 Ouled Aissa 18000 Jijel Algeria Northumbria Univ Newcastle Fac Engn & Environm Dept Comp & Informat Sci Newcastle Upon Tyne Tyne & Wear England Univ Mohammed Seddik Benyahia Jijel Dept Elect BP 98 Ouled Aissa 18000 Jijel Algeria Univ Mohammed Seddik Benyahia Jijel Dept Elect Lab Phys Rayonnement & Applicat BP 98 Ouled Aissa 18000 Jijel Algeria

In this paper, an enhanced version of embedded zerotree wavelet (EZW) image coding algorithm is proposed, referred to as EZW-SC. By exploiting a new principle that relies on a subband classification concept, the enhanced algorithm allows the prediction of insignificant subbands at early passes, along with the use of an improved significance map. This reduces the redundancy of zerotree symbols, speeds up the coding process and improves the coding of significant coefficients. In fact, the EZW-SC algorithm scans only significant subbands and significantly improves the lossy compression performance with the conventional EZW. Moreover, new EZW-based schemes are presented to perform colour image coding by taking advantage of the interdependency of the colour components. Experimental results show clear superiority of the proposed algorithms over the conventional EZW as well as other related EZW schemes at various bit rates in both greyscale and colour image compression.

关键词： embedded image coding Zeotree coding Wavelet compression

来源：评论

学校读者我要写书评

暂无评论

Lossless region of interest coding

引用

SIGNAL PROCESSING 1999年第1期78卷 1-17页

作者： Nister, D Christopoulos, C Ericsson Telecom AB Compress Lab CLAB TNETXPNXML S-12625 Stockholm Sweden

This paper describes a method that uses the well known S + P and TT transforms to encode a specially important part of an image, a region of interest (ROI) in a lossless mode. Other parts of the image (the background) are given lower quality levels allowing higher compression. The ROI coding is done in the framework of an embedded wavelet-based image compression algorithm. Entire coding, regional and full image, is done in a naturally progressive manner all the way up to lossless. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： region of interest lossless coding embedded image coding image compression wavelets

来源：评论

学校读者我要写书评

暂无评论

Adaptive multimedia transcoding for WWW content delivery

Adaptive multimedia transcoding for WWW content delivery

引用

International Conference on Industrial and Information Systems

作者： Samarasinghe, Rohan Nishantha, Durninda YasuTake, Yoshihiro Rodrigo, Lanka Yoshida, Takaichi Kyushu Inst Technol Dept Creat Informat 680-4 Kawazu Iizuka Fukuoka 8208502 Japan

ISBN: (纸本)9781424403219

The explosive growth of the network, end-host performances and their heterogeneities have resulted ever changing advancement and complexity of distributed computing environments. The users in such environment have not been provided a satisfactory service when they access the required objects. In this paper we focus on adaptive WWW content delivery, which is the most ubiquitous and popular way of information dissemination, primarily in the form of web-server, web-browser interaction. In these applications, we address controlling the Quality of delivery and time of access tradeoff of the WWW contents. We implement this as a httpa protocol, which is an adaptive transcoding methodology for embedded images in web pages, according to available channel bandwidth and other accessibility parameters at the client side. Compared to the conventional form of server side adaptive content delivery proposed in the literature, we propose a hybrid form of adaptation: client side progressive parameter estimation and server side transcoding of images, which is more scalable and flexible. Through experimental results we verify the performance of httpa.

关键词： Internet client-server systems image coding information dissemination multimedia systems transcoding Web pages Web-browser interaction adaptive WWW content delivery adaptive multimedia transcoding distributed computing environment embedded image coding h transcoding embedded image coding Information Dissemination Web pages MULTI-MEDIA SYSTEM client-server systems image coding Content distribution Servers Internets

来源：评论

学校读者我要写书评

暂无评论

A comparative study of DCT and wavelet based coding

A comparative study of DCT and wavelet based coding

引用

Conference on Applications of Digital image Processing XX

作者： Xiong, ZX Orchard, MT Ramchandran, K Dept of Electrical Engineering Princeton University Princeton NJ 08544 United States

ISBN: (纸本)0819425869

We study the performance difference of the discrete cosine transform (DCT) and the wavelet transform for both image and video coding, while comparing the other aspects of the coding system on an equal footing. Based on the state-of-the-art coding techniques, we point out that, for still images, the performance gap between DCT and wavelet based coding is within one dB in PSNR at the same bitrate. This is in contrast to the common perception that the wavelet transform is much superior to the DCT for image compression. For video coding, the advantage of using the wavelet transform over the DCT is even less pronounced.

关键词： discrete cosine transform (DCT) zero tree quantization embedded image coding wavelets

来源：评论

学校读者我要写书评

暂无评论

Tree Structures and Algorithms for Hybrid Transforms

Tree Structures and Algorithms for Hybrid Transforms

引用

International Conference on Signal Processing and Communications

作者： Rao, Chaithanya Bhokare, Ganesh Kumar, Ujjwal Patwardhan, Pushkar Gadre, Vikram M. Indian Inst Technol Dept Elect Engn Bombay 400076 Maharashtra India

ISBN: (纸本)9781424471379

Zerotree based image coding techniques use a standard multiresolution representation of images obtained by a repeated 2-band Discrete Wavelet Transform of images. A lot more modularity and flexibility can be achieved by use of hybrid transforms of images. In this paper we explore the advantages, issues and tree structures for hybrid transforms of images. A few new algorithms for embedded image coding using hybrid transforms have been drafted. The results, interpretations and scenarios where hybrid transforms might find better application than existing methods have been discussed.

关键词： embedded image coding Hybrid Transforms Tree Structures

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：