检索结果-内蒙古大学图书馆

IEEE Workshop on Neural Networks for Signal Processing

作者： S.Y. Kung Princeton University USA

This paper compares the use of the kurtosis function and higher-order moment functions for the extraction of independent components from a hybrid mixture. The kurtosis function, based on the 4-th order moments, is a theoretically attractive contrast function since it possess a traceable extrema-correspondence. Numerical motivations have lead many researchers to look into contrast functions involving higher-order moments. To facility the study, we define super-ness and sub-ness of non-Gaussian processes as terms that are dependent not only only on the nature of the signals themselves, but also on the the contrast functions used. In terms of the extrema-correspondence, we report some noteworthy discrepancies between the kurtosis and higher-order moment functions. Finally, we verify that for even-positive-integer and equal-moment components, both the necessary and sufficient conditions are valid.

关键词： Independent component analysis Optimized production technology Flip-flops Deconvolution Feature extraction Sensor arrays Sensor phenomena and characterization Array signal processing entropy coding Noise reduction

来源：评论

学校读者我要写书评

暂无评论

Vector quantization of scale factors in advanced audio coder (AAC)

Vector quantization of scale factors in advanced audio coder...

引用

International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： T.V. Sreenivas M. Dietz Audio/Multimedia Department Fraunhofer Institute of Integrated Circuits and Systems Erlangen Germany

This paper describes some experiments to reduce the load of the side information in the MPEG advanced audio coder (AAC) scheme using vector quantization (VQ) methods. The VQ replaces the existing differential and entropy coding of the scale factors. Various types of VQ are considered, such as sub-vector VQ, multi-stage VQ and tree-structured VQ which provide some advantages in the context of MPEG-4 AAC characteristics such as scaleability etc. However, the VQ being a lossy compression scheme, psycho-acoustic sensitivity of the losses is very important. These are studied using objective measures such as NMR and listening tests to make proper choices for the VQ design.

关键词： Vector quantization Bit rate Psychology Transform coding entropy coding Bandwidth Telephony Speech coding Psychoacoustic models Nuclear magnetic resonance

来源：评论

学校读者我要写书评

暂无评论

Packet loss concealment in baseline JPEG coded images

Packet loss concealment in baseline JPEG coded images

引用

IEEE Symposium on Advances in Digital Filtering and Signal Processing

作者： S. Shirani F. Kossentini R. Ward Department of Electrical and Computer Engineering University of British Columbia Vancouver BC Canada

Loss of coded data can affect a JPEG decoded image to a large extent, making concealment of errors caused by data loss an important issue. Reconstruction of JPEG coded images in an error-prone channel environment is investigated in this paper. First a method for estimating the missing DC coefficients of a JPEG coded image which is required for decoding the compressed image, is suggested and evaluated. As the effects of errors in estimating the missing DC value will appear as stripes across the image, a post-processing technique for removing such stripes is then developed. Finally the missing data is reconstructed by exploiting the correlation between adjacent blocks. A novel reconstruction technique which has a good performance in reconstruction of edges is proposed. A key contribution of our work is that, unlike in previously published reconstruction algorithms, differential encoding of the DC coefficients is assumed. Simulation results indicate that the performance of our algorithm is very good, even when many packets are lost during transmission of the JPEG coded image.

关键词： Decoding Transform coding Image reconstruction Image coding Discrete cosine transforms Reconstruction algorithms Computer errors Propagation losses Quantization entropy coding

来源：评论

学校读者我要写书评

暂无评论

Jointly optimal classification and uniform threshold quantization in entropy constrained subband image coding

Jointly optimal classification and uniform threshold quantiz...

引用

International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： A. Hjorungnes J.M. Lervik Department of Telecommunications Norwegian University of Science and Technology Trondheim Norway

A method for coding a source modeled by an infinite Gaussian mixture distribution is proposed. The source is first split into N classes. The samples of each class are then quantized by an infinite-level uniform threshold quantizer followed by an entropy coder designed for each class. The problem of joint optimization of this system's rate distortion performance is first solved theoretically, assuming an exponential mixing density. A comparison to a system optimal for high rates, using one common quantizer for all classes, showed that for a fixed distortion the rate was reduced by 11-12% at low rates for a fixed N=5. A subband image coder, using the optimum theoretical parameter values was simulated. The resulting coder has high performance and low complexity.

关键词： Image coding Statistical distributions Rate-distortion Filter bank entropy coding Frequency Optimization methods Rate distortion theory Vector quantization Inspection

来源：评论

学校读者我要写书评

暂无评论

Minimum-entropy clustering and its application to lossless image coding

Minimum-entropy clustering and its application to lossless i...

引用

IEEE International Conference on Image Processing

作者： F. Golchin K.K. Paliwal School of Microelectronic Engineering Griffith University Brisbane QLD Australia

The minimum-entropy clustering (MEC) algorithm proposed in this paper provides an optimal method for addressing the non-stationarity of a source with respect to entropy coding. This algorithm clusters a set of vectors (where each vector consists of a fixed number of contiguous samples from a discrete source) using a minimum entropy criterion. In a manner similar to classified vector quantization (CVQ), a given vector is first classified into the class which leads to the lowest entropy and then its samples are coded by the entropy coder designed for that particular class. The MEC algorithm is used in the design of a lossless, predictive image coder. The MEC-based coder is found to significantly outperform the single entropy coder as well as the other popular lossless coders reported in the literature.

关键词： Clustering algorithms entropy coding Vector quantization Algorithm design and analysis

来源：评论

学校读者我要写书评

暂无评论

BLOCK TRUNCATION coding WITH entropy coding

引用

IEEE TRANSACTIONS ON COMMUNICATIONS 1995年第2-4期43卷 1677-1685页

作者： FRANTI, P NEVALAINEN, O Department of Computer Science University of Turku Turku Finland

Block Truncation coding (ETC) is a simple and fast image compression algorithm which achieves constant bit rate of 2.0 bits per pixel, The method is however suboptimal. In the present paper we propose a modification of ETC in which the compression ratio will be improved by coding the quantization data and the bit plane by arithmetic coding with an adaptive modelling scheme. The results compare favorable with other ETC variants. The bit rate for test image Lena is 1.53 bits per pixel with the mean square error of 16.51.

关键词： compression ratio constant bit rate (CBR) pixel image compression algorithm entropy coding arithmetic coding Mean square error Block truncation coding

来源：评论

学校读者我要写书评

暂无评论

A video coding algorithm using vector-based techniques

引用

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1997年第1期7卷 146-157页

作者： Li, WP Cao, HQ Li, SP Ling, F Segan, SA Sun, HQ Wus, JP Zhang, YQ DAVID SARNOFF RES CTR PRINCETON NJ 08543 USA

This paper presents an algorithm proposal submitted to MPEG-4 for video coding. The proposed algorithm addresses the functionality of improved coding efficiency for compression. It uses vector-based techniques for coding intraframes (the first frame and subsequent refreshing key frames) and motion-compensated difference frames. It uses the same motion estimation and motion compensation techniques as H.263. A video frame (I or P frame) is first decomposed into a set of vector bands using a vector wavelet transform. This stage of vector-based signal processing makes subsequent vector quantization in the vector bands very efficient. Lattice vector quantization is then used in the vector bands. A 100% labeling efficiency is achieved for lattice vector quantization by using a set of generalized labeling algorithms for various important lattices with pyramid and sphere boundaries. Finally, entropy coding is used to code the indexes generated from lattice vector quantization. Our coding results have shown that a gain in peak signal-to-noise ratio (PSNR) up to 8 dB for intraframe coding and up to 6 dB for interframe coding can be achieved over H.263. Subjective quality improvement of the proposed algorithm over H.263 can be easily observed.

关键词： data compression entropy coding international standard lattice labeling quantization signal processing vector processing vector quantization video coding wavelet transform

来源：评论

学校读者我要写书评

暂无评论

Context-based, adaptive, lossless image coding

引用

IEEE TRANSACTIONS ON COMMUNICATIONS 1997年第4期45卷 437-444页

作者： Wu, XL Memon, N NO ILLINOIS UNIV DEPT COMP SCIDE KALBIL 60115

We propose a context-based, adaptive, lossless image codec (CALIC). The codec obtains higher lossless compression of continuous-tone images than other lossless image coding techniques in the literature, This high coding efficiency is accomplished with relatively low time and space complexities, CALIC puts heavy emphasis on image data modeling. A unique feature of CALIC is the use of a large number of modeling contexts (states) to condition a nonlinear predictor and adapt the predictor to varying source statistics, The nonlinear predictor can correct itself via an error feedback mechanism by learning from its mistakes under a given context in the past. In this learning process, CALIC estimates only the expectation of prediction errors conditioned on a large number of different contexts rather than estimating a large number of conditional error probabilities, The former estimation technique can afford a large number of modeling contexts without suffering from the context dilution problem of insufficient counting statistics as in the latter approach, nor from excessive memory use, The low time and space complexities are also attributed to efficient techniques for forming and quantizing modeling contexts.

关键词： adaptive prediction entropy coding image compression statistical context modeling

来源：评论

学校读者我要写书评

暂无评论

Comparative color space analysis of difference images from adjacent visible human slices for lossless compression

Comparative color space analysis of difference images from a...

引用

Conference on Applications of Soft Computing

作者： Thoma, GR Pipkin, R Mitra, S National Library of Medicine (United States) Texas Tech Univ. (United States)

ISBN: (纸本)0819425877

This paper reports the compression ratio performance of the RGB, YIQ, and HSV color plane models for the lossless coding of the National Library of Medicine's Visible Human (VH) color data set. In a previous study [1] the correlation between adjacent VH slices was exploited using the RGB color plane model. The results of that study suggested an investigation into possible improvements using the other two color planes, and alternative differencing methods. YIQ and HSV, also known as HSI, both represent the image by separating the intensity from the color information, and we anticipated higher correlation between the intensity components of adjacent VH slices. However the compression ratio did not improve by the transformation from RGB into the other color plane models, since in order to maintain lossless performance, YIQ and HSV both require more bits to store each pixel. This increase in file size is not offset by the increase in compression due to the higher correlation of the intensity value, the best performance being achieved with the RGB color plane model. This study also explored three methods of differencing: Average Reference Image, Alternating Reference Image, and Cascaded Difference from Single Reference. The best method proved to be the first iteration of the Cascaded Difference from Single Reference. In this method, a single reference image is chosen, and the difference between it and its neighbor is calculated. Then the difference between the neighbor and its next neighbor is calculated. This method requites that all preceding images up to the reference image be reconstructed before the target image is available. The compression ratios obtained from this method are significantly better than the competing methods.

关键词： Visible Human image entropy coding color plane model YIQ HSV RGB image compression

来源：评论

学校读者我要写书评

暂无评论

Lattice vector quantization with reduced or without look-up table.

Lattice vector quantization with reduced or without look-up ...

引用

Visual Communications and Image Processing 1998 Conference

作者： Rault, P Guillemot, C CCETT F-35510 Cesson Sevigne France

ISBN: (纸本)0819427497

This paper describes a new vector indexing algorithm for Lattice Vector Quantization, (LVQ). The technique applies to a large class of lattices such as Z(n), A(n), D-n or E-8, widely used in signal compression. Relying on a partitioning of the events sources, based on a notion of leaders as proposed in,(1) it allows to trade vector look-up table size for arithmetic operations. At the cost of a very small number of integer arithmetic operations, the algorithm leads to a very significant reduction of the vector look-up tables. This in turn leads to reduced encoder and decoder complexities. The introduction of the concept elf 'absolute' leaders, and of the corresponding coding and decoding algorithms, provides additional flexibility in trading table size for arithmetic operations. The association of these vector indexing techniques with product codes, in the framework of Lattice Vector Quantization, leads to increased compression performances.

关键词： lattice vector quantization vector indexing entropy coding data compression image and video 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：