检索结果-内蒙古大学图书馆

6th International Conference on Signal Processing, ICSP 2002

作者： Boyer, Rémy Essid, Slim Moreau, Nicolas ENST Department of Signal and Image Processing 46 rue Barrault Paris Cedex 1375634 France

ISBN: (纸本)0780374886

low bit rate audio coding often relies on Fourier representation despite its limitations for transient signal modeling. This study proposes alternative decompositions and expansion strategies that lead to more accurate modeling. Two classes of methods are considered, subspace decom-position methods, and atomic decomposition methods and their performances are compiled to propose an audio modeling scheme amenable to low bit rate coding. © 2002 ieeE.

关键词： Codes (symbols)

来源：评论

学校读者我要写书评

暂无评论

A low bit-rate video-coding algorithm based upon variable pattern selection 6

A low bit-rate video-coding algorithm based upon variable pa...

引用

6th International Conference on Signal Processing

作者： Paul, M Murshed, M Dooley, L Monash Univ Gippsland Sch Comp & Info Tech Churchill Vic 3842 Australia

ISBN: (纸本)0780374886

Recent research into pattern representation of moving regions in blocked-based motion estimation and compensation in video sequences has focused mainly upon using a fixed number of regular shaped patterns. These are used to match the macroblocks in a frame that have two distinct regions involving static background and moving objects. In thus paper a new Variable Pattern Selection (VPS). algorithm is presented which selects a preset number of best-matched patterns from a pattern codebook of regular shaped patterns. While more patterns are used than in the previous work, the performance of the VPS algorithm in using variable length, coding. by exploiting the frequency of the, best-matched patterns, leads to a higher compression ratio, without degrading the overall image quality.

关键词： motion estimation and compensation low bit-rate video coding moving region detection pattern matching

来源：评论

学校读者我要写书评

暂无评论

A wavelet intra-frame coding algorithm based on information source partition theorem 6

A wavelet intra-frame coding algorithm based on information ...

引用

6th International Conference on Signal Processing, ICSP 2002

作者： Jianqiu, Liu Qiuqi, Ruan Institute of Information Science Northern Jiaotong University Beijing100044 China

ISBN: (纸本)0780374886

In this paper, we propose a new wavelet imtra-frame coding algorithm based on Information Source Partition Theorem. The algorithm is motivated by SPIHT algorithm, but it is more efficient than SPIHT codec and can also produce completely embedded coding bit stream. The experiment results show that our algorithm is very suitable to very low bit-rate video coding. Compared with H.263 intra-frame coding algorithm, our codec achieved better reconstructed image than H.263 intra-frame codec at the same compression ratio. © 2002 ieeE.

关键词： Wavelet transforms

来源：评论

学校读者我要写书评

暂无评论

In-loop deblocking filter for block-based video coding 6

In-loop deblocking filter for block-based video coding

引用

6th International Conference on Signal Processing

作者： Sun, XY Wu, F Li, SP Gao, W Harbin Inst Technol Dept Comp Applicat Harbin 150001 Peoples R China

ISBN: (纸本)0780374886

Blocking artifacts are the inherent and inevitable phenomena, at low bit rates in the current block-based video coding schemes. This paper proposes a deblocking technique to reduce blocking artifacts and improve visual quality. Different from the post-processing technique adopted in MPEG-4, the proposed technique is directly applied to the reference image for effective motion prediction instead of just for display purpose. In other words, the deblocking filter is introduced into the motion compensation loop in the video coding. Because of the negative effects of deblocking filter such as blurring the details of image, not every block boundary needs to be filtered. The boundaries between two blocks have to be determined whether they should be filtered or not. Therefore, we also propose a decision-making criterion based on the available motion information (vector and mode) in this paper. Experimental results show that the proposed deblocking method can improve image quality both in subjective and objective aspects. It also outperforms the post-processing technique in MPEG-4.

关键词： image coding

来源：评论

学校读者我要写书评

暂无评论

Wavelet-based very low bit-rate video coding using image warping and overlapped block motion compensation

引用

iee PROCEEDINGS-VISION image AND SIGNAL PROCESSING 2001年第2期148卷 93-101页

作者： Heising, G Marpe, D Cycon, HL Petukhov, AP Heinrich Hertz Inst Commun Technol Image Proc Dept Berlin Germany Fachhsch Tech & Wirtschaft Berlin Germany Univ S Carolina Dept Math Columbia SC 29208 USA

The authors present an algorithm for very low bit-rate video coding that combines new ideas in motion estimation, wavelet filter design, and wavelet-based coding techniques. A new motion compensation technique using image warping and overlapped block motion compensation is proposed to reduce temporal redundancies in a given image sequence. This combined motion model has the advantage of representing more complex motion than simple block matching schemes. To further improve the quality of the temporal prediction, an adaptive grid with variable density according to the varying motion activity of a given scene is generated. An adaptively switched high-quality texture interpolation is employed to cope with the problem of fractional displacements in such a way that both objective and subjective reconstruction quality is improved. Spatial decorrelation of the motion compensated residual images is performed using an one-parametric family of biorthogonal infinite impulse response (IIR) wavelet filters coupled with the highly efficient pre-coding scheme of 'partitioning, aggregation and conditional coding' (PACC). Experimental results demonstrate significant improvements in objective quality of 1.0-2.3 dB PSNR in comparison to the H.263+ test model TMN10 using advanced coding options. In addition, the authors' intracoding method provides a performance gain of 0.5 dB PSNR on the average for a test suite of various still images when compared to the emerging still image coding standard JPEG-2000.

关键词： .transform coding compensation image warping motion discontinuities motion vector block motion OBMC warping model

来源：评论

学校读者我要写书评

暂无评论

Novel rate-distortion analysis framework for bit rate and picture quality control in DCT visual coding

Novel rate-distortion analysis framework for bit rate and pi...

引用

作者： He, Z. Mitra, S.K. Sarnoff Corporation 201 Washington Rd Princeton NJ 08543 United States

The rate-distortion (R-D) behaviour of a coding system depends on both the characteristics of the input source data and the coding algorithm. The authors introduce the new concepts of characteristic rate curves and rate curve decomposition to characterise the input source data and model the coding algorithm, respectively. Based on these concepts, a novel framework for R-D analysis is developed, which serves as an alternative to the classical R-D analysis. Based on this framework, a fast algorithm is proposed to predict the R-D curve before quantisation and coding. The proposed algorithm has very low computational complexity. However, in the extensive simulations, its relative prediction error is always less than 5%, which is very small. To the best of the authors' knowledge, this is the first algorithm which is able to accurately estimate the R-D curve before quantisation and coding. With the estimated R-D curve, it is possible to accurately control the output bit rate and picture quality for transform coding of still images and video sequences. In practical visual coding applications, with the proposed R-D estimation algorithm, the coding bit rate can be accurately matched to the available network bandwidth to guarantee the successful transmission of the coded image/video data.

关键词： image coding

来源：评论

学校读者我要写书评

暂无评论

Adaptive MLP post-processing for block-based coded images

引用

iee PROCEEDINGS-VISION image AND SIGNAL PROCESSING 2000年第5期147卷 463-473页

作者： Huang, YL Chang, RF Natl Chung Cheng Univ Dept Comp Sci & Informat Engn Chiayi 62107 Taiwan

Block-based image coding techniques are widely used for encoding images and videos. However. many annoying artefacts appear when an image is encoded at low bit rates. In these artefacts, the blocking effects are very obvious to human vision. Thus, an efficient blocking effect reduction scheme is essential for preserving the visual quality of decompressed images. A new adaptive post-processing algorithm is proposed to reduce the blocking artefacts of block-based coded images by using neural network techniques in the spatial domain. The algorithm combines a variance-based classifier and multilayer perceptrons to improve the performance of post-processing. In the proposed algorithm, the blocking and ringing effects in a reconstructed image are diminished without blurring of the edges, and the detailed region in the image is also enhanced. Comparison results between the proposed algorithm and other algorithms are made with several Joint photographic Experts Group and vector quantisation decompressed images. In the simulations, the results of reconstructed images with improvements in both visual quality and PSNR are shown. It is found that the proposed algorithm is an effective post-processing algorithm for block-based image coding at low bit rates.

关键词： .transform coding video compression image coding bit rates MLP decompressed reconstructed images coded images blocking effects

来源：评论

学校读者我要写书评

暂无评论

New methodology for adaptive vector quantisation

引用

iee PROCEEDINGS-VISION image AND SIGNAL PROCESSING 2000年第6期147卷 581-586页

作者： Scargall, LD Dlay, SS Univ Newcastle Upon Tyne Dept Elect & Elect Engn Newcastle Upon Tyne NE1 7RU Tyne & Wear England

An image sequence coding scheme for low bit-rate video coding is presented. A new methodology is proposed for adaptive vector quantisation (AVQ), where the codebook is updated with new code-vectors. The new code-vectors replace less significant ones in the codebook, based on a novel-scoring criterion that utilises a forgetting factor and codebook half-life. The proposed AVQ method gives rise to an additional performance enhancement of approximately 1 dB over frequency scoring techniques.

关键词： .compensation image coding updates DFD codecs intra-frame vector quantisation kbitls

来源：评论

学校读者我要写书评

暂无评论

Entropy-coded pyramid vector quantisation for interband wavelet image coding

引用

iee PROCEEDINGS-VISION image AND SIGNAL PROCESSING 2000年第4期147卷 304-312页

作者： Vij, M Kingsbury, N Silicon & Software Syst Dublin 18 Ireland Univ Cambridge Dept Engn Cambridge CB2 1PZ England

Novel class-based entropy coding algorithms for lattice quantised hierarchical (or interband) vectors are presented. The vectors an formed from wavelet coefficients on different scales from similarly oriented sub-bands corresponding to the same spatial location. Structures have been designed specifically for interband vectors drawn from wavelet coefficients, where large groups of approximately equiprobable lattice points are grouped into relatively few classes, known as sub-classes, super-classes and super-super-classes, enabling accurate probability estimates from training data to be obtained for entropy coding of the class indices. Further, it has been found that the best quantiser is a combination of the Z(n) and D-n lattices which has been termed an augmented lattice. The performance of the method, entitled entropy-coded pyramid vector quantisation (ECPVQ), is evaluated on real images and the results show that ECPVQ is competitive, particularly at low bit-rates, with current state-of-the-art wavelet-based coders. A subjective comparison with current high performance scalar quantisation based coders shows that ECPVQ is likely to better preserve fine texture detail in the decoded images because of the finer quantisation of low energy wavelet coefficients that occurs with the augmented lattice.

关键词： .image coding lattices sub-band interband quantisation lattice points quantisers entropy codes

来源：评论

学校读者我要写书评

暂无评论

Improvements of the SPIHT for image coding by wavelet transform

Improvements of the SPIHT for image coding by wavelet transf...

引用

作者： Zhu, Jian Lawson, Stuart School of Engineering University of Warwick Coventry CV4 7AL United Kingdom

The SPIHT (set partitioning in hierarchical trees) is an efficient image coding method using the wavelet transform. Two improvements of the SPIHT are presented in this paper. One is to use a new type of tree, to hold as many wavelet coefficients as possible during initialization. The other is to omit the predictable coding symbols for the significance indication of the coefficient sets or individual coefficients. The first improvement increases the compression ratio of low bit-rate image coding, while the second favours relatively high bit-rate image coding. The implementation of the SPIHT is re-designed to include the two improvements. The computation complexity is not increased on using these improvements. Simulation results show significant performance gain of the improvements.

关键词： image coding

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：