检索结果-内蒙古大学图书馆

IEEE International Symposium on Information Theory

作者： S. Sandeep Pradhan David L. Neuhoff EECS Department University of Michigan Ann Arbor MI USA

ISBN: (纸本)9781424413973;1424413974

With mean-squared error D as a goal, it is well known that one may approach the rate-distortion function R(D) of a nonbandlimited, continuous-time Gaussian source by sampling at a sufficiently high rate, applying the Karhunen-Loeve transform to sufficiently long blocks, and then independently coding the transform coefficients of each type. In particular, the coefficients of a given type are ideally encoded with performance attaining a suitably chosen point on the first-order rate-distortion function of that type of coefficient. This paper considers a similar sample-and-transform coding scheme in which ideal coding of coefficients is replaced by coding with some specified family of quantizers, whose operational rate-distortion function is convex. A prime example is scalar quantization with entropy-coding and, if needed for convexity, time sharing. It is shown that when the sampling rate is large, the operational rate-distortion function of such a scheme comes within a finite constant of R(D). Applied to the scalar quantization family, the finiteness of this bound contrasts with a recent result showing that direct scalar quantization of samples (without a transform) has unbounded rate when distortion is held constant and sampling rate becomes large, even when the quantized samples are compressed to their entropy-rate. Thus, at high sampling rates, the transform reduces the loss due to scalar quantization from something infinite to something finite.

关键词： transform coding Sampling methods Rate-distortion Quantization Decoding Karhunen-Loeve transforms Time sharing computer systems Rate distortion theory Random processes Discrete transforms

来源：评论

学校读者我要写书评

暂无评论

transform coding of synthetic aperture radar (SAR) images

Transform coding of synthetic aperture radar (SAR) images

引用

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

作者： T. Gioutsos S. Werness Environmental Research Institute of Michigan Ann Arbor MI USA

transform coding is a type of source coding that is used to compress the data required for images without substantial loss of fidelity. transform coding has been studied by many authors for optical images and the results have shown favorable compression ratios on the order of 10 to 1 without noticeable loss of picture quality. This is due to the highly correlated nature of typical images. Observable autocorrelation lags for SAR imagery seldom occur past lags of 3 or 4. However, since correlation exists, a reduction of the data can be achieved. The approach taken in this paper was to achieve data compression on SAR images by the use of Karhunen-Loeve, Walsh and Cosine transform coding. All coefficients of each transform were allocated a variable number of bits using the Huang and Schultheiss [1] approach followed by the Lloyd-Max quantizer [2,3]. Experiments were done with several variations of the basic transform coding scheme.

关键词： transform coding Synthetic aperture radar Karhunen-Loeve transforms Pixel Discrete cosine transforms Covariance matrix Image coding Optical filters Bit rate Discrete transforms

来源：评论

学校读者我要写书评

暂无评论

transform coding of color images with limited palette size

Transform coding of color images with limited palette size

引用

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

作者： A. Zaccarin B. Liu Dept. of Electr. Eng. Princeton Univ. NJ USA Department of Electrical Engineering Princeton University Princeton NJ USA

An approach for the compression of color images with limited palette size that does not require color quantization of the decoded image is presented. The technique restricts the pixels of the decoded image to take values only in the original palette. Thus, the decoded image can be readily displayed without having to be quantized. Results obtained with a typical image are included to compare a conventional coding scheme to the proposed one. For comparable quality and bit rates, the proposed technique significantly reduces the decoder computational complexity.< >

关键词： transform coding Color Image coding Decoding Pixel Displays Discrete cosine transforms Quantization Bit rate Computational complexity

来源：评论

学校读者我要写书评

暂无评论

transform coding by lateral inhibited neural nets

Transform coding by lateral inhibited neural nets

引用

International Conference on Tools for Artificial Intelligence (ICTAI)

作者： R.W. Brause J.W. Goe University Frankfurt Germany

One of the most popular encoding techniques for sensor data is transform coding. This encoding schema is composed of two stages: a linear transformation stage with a nonzero kernel and a vector quantization stage. For the first stage, the author describes a new implementation approach by artifical neural networks. The problem of determining the optimal transformation coefficients is solved by learning the coefficients by a lateral inhibited neural network. After a short introduction to the topic the author focuses on this model and a local stability analysis of the fixpoints for the serial dynamics is provided. The resulting parameter regime is used in a network simulation example using picture statistics. Additionally, the simulations reveal that a biologically-like growing lateral inhibition influence leads to a speed-up of the learning convergence of that model.

关键词： transform coding Neural networks Biological system modeling Encoding Kernel Vector quantization Stability analysis Statistics Biological information theory Convergence

来源：评论

学校读者我要写书评

暂无评论

transform coding at 4.8 kbit/sec using interleaving of transform frames and dual gain-shape vector quantisation

Transform coding at 4.8 kbit/sec using interleaving of trans...

引用

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

作者： P.M. McCourt H.A. Kaouri Department of Electrical and Electronic Engineering Queen''s University Belfast Belfast UK

The dual gain shape VQ (vector quantization) transform coding algorithm refines the distribution of quantization resources by supplementing interband bit allocation with intraband reallocation, and, by introducing two levels of vector normalization, allows the design of more efficient codebooks. Better use of limited bit resources at the coding rate of 4.8 kbit/s is thus achieved, yielding a 1 dB improvement in coding performance. The introduction of frame overlapping in the transform domain, by implementing a continuous frame interleave, gives significant improvements in the subjective quality of the coded speech. The effect produced by interleaving could be explained as an exploitation of interframe correlation, in creating vectors for VQ, and as an implicit promotion of frame interdependency in bit allocations.< >

关键词： transform coding Interleaved codes Bit rate Discrete transforms Quantization Algorithm design and analysis Shape Resource management Power distribution Speech

来源：评论

学校读者我要写书评

暂无评论

Scalable audio coding based on hierarchical transform coding modules

引用

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 2001年第8期84卷 34-45页

作者： Jin, A Moriya, T Iwakami, N Miki, S NTT Cyber Space Labs Musashino Tokyo 1808585 Japan

We propose a method that hierarchically quantizes wideband Modified Discrete Cosine transform (MDCT) coefficients by developing a module that has a transform coding method primarily for audio as the basic structural unit and freely using this module multiple times at the desired frequencies. The major feature of this method is to implement a simple structure having a high degree of freedom in scalable coding to hierarchically quantize MDCT coefficients over a wide band of frequencies by sharing the proposed module and using it multiple times. This paper presents examples using combinations of the module operating at a sampling frequency of 48 kHz and a bit rate of at least 8 kbit/s. In this example, a bit rate of at least 8 kbit/s and a reconstructed frequency band of at least 4 kHz can de selected as the objective. Subjective evaluation tests are performed to verify the effectiveness oft he proposed method. (C) 2001 Scripta Technica

关键词： audio coding transform coding TwinVQ coding scalable coding hierarchical quantization

来源：评论

学校读者我要写书评

暂无评论

Compression of multispectral images by spectral classification and transform coding

引用

IEEE TRANSACTIONS ON IMAGE PROCESSING 1999年第4期8卷 476-489页

作者： Gelli, G Poggi, G Univ Naples Federico II Dipartimento Ingn Elettron & Telecomunicaz I-80125 Naples Italy

This paper presents a new technique for the compression of multispectral images, which relies on the segmentation of the image into regions of approximately homogeneous land cover, The rationale behind this approach is that, within regions of the same land cover, the pixels have stationary statistics and are characterized by mostly linear dependency, contrary to what usually happens for unsegmented images. Therefore, by applying conventional transform coding techniques to homogeneous groups of pixels, the proposed algorithm is able to effectively exploit the Statistical redundancy of the image, thereby improving the rate distortion performance. The Proposed coding strategy consists of three main steps. First, each pixel is classified by vector quantizing its spectral response vector, so that both a reliable classification and a minimum distortion encoding of each vector are obtained. Then, the classification map is entropy encoded and sent as side information. Finally, the residual vectors are grouped according to their classes and undergo Karhunen-Loeve transform in the spectral domain and discrete cosine transform in the spatial domain. Numerical experiments on a;six-band thematic mapper image show that the proposed technique outperforms the conventional transform coding technique by 1 to 2 dB at all rates of interest.

关键词： classification compression multispectrtal images remote sensing transform coding

来源：评论

学校读者我要写书评

暂无评论

ADAPTIVE KARHUNEN-LOEVE transform coding AND ITS DESIGN METHOD

引用

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 1995年第5期78卷 10-21页

作者： OHZEKI, K Member Kansai Research Laboratory Toshiba Corporation Kobe Japan 658

Specific models have been conventionally used to switch between various Karhunen-Loeve (KL) transform matrices to adapt to local characteristics of nonstationary images. Here, the superior characteristic of the KL transform (mean square error minimization) is extended over all parts of the design process as an evaluation criterion. Further, by using actual images as training data, a design process is established that reflects the nature of real images. In order to compare the adaptive matrix-switching KL transform coding method with previous simple discrete cosine transform (DCT) coding methods, a transform is proposed that does not cause mean value separation. The effectiveness of this type of adaptive transform is determined by computer simulation. Also, since the resulting coding characteristics do not depend on the training images, it is estimated that the construction of a system that includes common nonstationary characteristics has been achieved;Examination of intermediate steps of this design process show that, in fact, all generated eigenvalues are practically positive and the stability of the design process is guaranteed.

关键词： transform coding KL transform ADAPTIVE SIGNAL PROCESSING LEAST MEAN SQUARE ERROR OPTIMIZATION

来源：评论

学校读者我要写书评

暂无评论

Rate-distortion optimized adaptive transform coding

引用

OPTICAL ENGINEERING 2009年第8期48卷 087004-087004页

作者： Lim, Sung-Chang Kim, Dae-Yeon Jeong, Seyoon Choi, Jin Soo Choi, Haechul Lee, Yung-Lyul Elect & Telecommun Res Inst Broadcasting & Telecommun Convergence Media Res D Taejon 305700 South Korea Sejong Univ Dept Comp Engn Digital Media Syst Lab Seoul 143747 South Korea

We propose a rate-distortion optimized transform coding method that adaptively employs either integer cosine transform that is an integer-approximated version of discrete cosine transform (DCT) or integer sine transform (IST) in a rate-distortion sense. The DCT that has been adopted in most video-coding standards is known as a suboptimal substitute for the Karhunen-Loeve transform. However, according to the correlation of a signal, an alternative transform can achieve higher coding efficiency. We introduce a discrete sine transform (DST) that achieves the high-energy compactness in a correlation coefficient range of -0.5 to 0.5 and is applied to the current design of H. 264/AVC (advanced video coding). Moreover, to avoid the encoder and decoder mismatch and make the implementation simple, an IST that is an integer-approximated version of the DST is developed. The experimental results show that the proposed method achieves a Bjontegaard Delta-RATE gain up to 5.49% compared to Joint model 11.0. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3204239]

关键词： transform coding discrete cosine transform integer cosine transform discrete sine transform integer sine transform H.264/AVC

来源：评论

学校读者我要写书评

暂无评论

Efficient transform coding schemes for speech LSFs

引用

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 1999年第4期E82A卷 580-587页

作者： Vu, HL Tech Univ Budapest Dept Telecommun H-1111 Budapest Hungary

In this paper, the correlation properties are used to develop two efficient encoding schemes for speech line spectrum frequency (LSF) parameters. The first scheme (1D KL), which exploits the intraframe correlation, is based on one-dimensional Karhunen-Loeve (KL) transformation;the second scheme, which requires some coding delays to further utilize the interframe correlation, uses two-dimensional (2D KL) transform in the frequency domain or one-dimensional KL transform co-operating with DPCM in the time domain. Moreover, since the KL transform is globally optimal, which is sensitive to the change of input data statistics, further two adaptive transform coding systems are also investigated in this paper. The performance of all systems for different bit rates is investigated and adequate comparisons are made. It is shown that the gain of using KL transformation to exploit the intraframe and interframe correlation is 3 and 3 bits/speech frame, respectively.

关键词： speech spectral coding at low rate Karhunen-Loeve transformation transform 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：