检索结果-内蒙古大学图书馆

IEEE National Conference on Radar

作者： A.M. Haimovich C. Peckham T. Ayoub J.S. Goldstein I.S. Reed Electrical and Computer Engineering. Department New Jersey Institute of Technology University Heights Newark NJ USA Space Communications Branch USAF Rome Laboratory Rome NY USA Statistical Signal & Image Proc. Laboratory Department of Electrical Engineering University of Southern California Los Angeles CA USA

The space-time radar problem is well suited to the application of techniques that take advantage of the low-rank property of the space-time covariance matrix. In particular, it was shown that when the space-time covariance matrix is estimated from a dataset with limited support, reduced-rank methods outperform full-rank space-time adaptive processing (STAP). We study the application of several reduced-rank methods to the STAP problem and demonstrate their utility by simulations in terms of the output signal-to-noise ratio and detection probability. It is shown that reduced-rank processing has two opposite effects on the performance: increased statistical stability which tends to improve performance, and introduction of a bias which lowers the signal-to-noise ratio. Several reduced-rank methods are analyzed and compared for both cases of known and unknown covariance matrix. While the best performance is obtained using transforms based on the eigendecomposition (data dependent), the loss incurred by the application of fixed transforms (such as the discrete cosine transform) is relatively small. The main advantage of fixed transforms is the availability of efficient computational procedures for their implementation. These findings suggest that reduced-rank methods could facilitate the development of practical, real-time STAP technology.

关键词： Performance analysis Covariance matrix Discrete transforms Signal to noise ratio Radar applications Spaceborne radar Probability Stability Performance loss Discrete cosine transforms

来源：评论

学校读者我要写书评

暂无评论

Editorial

引用

International Journal of Pattern Recognition and Artificial Intelligence 1997年第8期11卷 1157-1160页

作者： W. C. Karl D. N. Kennedy A. J. Worth H. H. Pien A. S. Willsky Department of Electrical and Computer Engineering Boston University Boston MA 02215 USA Center for Morphometric Analysis Massachusetts General Hospital Charlestown MA 02129 USA Image Recognition Systems Draper Laboratory Cambridge MA 02139 USA Center for Morphometric Analysis Neuroscience Center Massachusetts General Hospital-East Building 149 13th St. Charlestown MA 02129-2000 USA

来源：评论

学校读者我要写书评

暂无评论

Convolution backprojection formulas for 3-D vector tomography with application to MRI

引用

IEEE TRANSACTIONS ON image PROCESSING 1996年第10期5卷 1462-1472页

作者： Prince, JL Department of Electrical and Computer Engineering Image Analysis and Communications Laboratory The Johns Hopkins tlniversity

Vector tomography is the reconstruction of vector fields from measurements of their projections, In previous work, it has been shown that reconstruction of a general three-dimensional (3-D) vector field is possible from the so-called inner product measurements, It has also been shown how reconstruction of either the irrotational or solenoidal component of a vector field can be accomplished with fewer measurements than that required for the full field, The present paper makes three contributions. First, in analogy to the two-dimensional (2-D) approach of Norton, several 3-D projection theorems are developed. These lead directly to new vector field reconstruction formulas that are convolution backprojection formulas, It is shown how the local reconstruction property of these 3-D reconstruction formulas permits reconstruction of point flow or of regional flow from a limited data set, Second, simulations demonstrating 3-D reconstructions, both local and nonlocal, are presented, Using the formulas derived herein and those derived in previous work, these results demonstrate reconstruction of the irrotational and solenoidal components, their potential functions, and the field itself from simulated inner product measurement data, Finally, it is shown how 3-D inner product measurements can be acquired using a magnetic resonance scanner.

关键词： backprojection Dot product potential function Convolution formula Three Dimensions Vector field irrotational three-dimensional displays

来源：评论

学校读者我要写书评

暂无评论

On div-curl regularization for motion estimation in 3-D volumetric imaging

On div-curl regularization for motion estimation in 3-D volu...

引用

IEEE International Conference on image Processing

作者： S.N. Gupta J.L. Prince Image Analysis and Communications Laboratory Department of Electrical and Computer Engineering Johns Hopkins University Baltimore MD USA

We consider the classical optical flow algorithm due to Horn and Schunck (1981) for estimating the motion of brightness patterns between image pairs. We use a modified smoothness condition based on the divergence and curl of the velocity field. In previous work, we have developed well-posed stochastic state-space models for these optical flow methods in two dimensions. This paper extends our results to 3-D. We first show that by using the first order div-curl spline, it is not possible to obtain a first order linear differential well-posed model in 3-D. Next, we employ the second order div-curl spline smoothness condition and develop well-posed state-space models.

关键词： Motion estimation Brightness image motion analysis Spline Stochastic processes Optical imaging Optical computing State-space methods image sequence analysis Laboratories

来源：评论

学校读者我要写书评

暂无评论

Experiments in multiresolution motion estimation for multifrequency tagged cardiac MR images

Experiments in multiresolution motion estimation for multifr...

引用

IEEE International Conference on image Processing

作者： S. Androutsellis-Theotokis J.L. Prince Image Analysis and Communications Laboratory Department of Electrical and Computer Engineering Johns Hopkins University Baltimore MD USA

In tagged magnetic resonance imaging of the human heart, different frequency patterns can be imposed and imaged as the heart moves. It is advantageous to use low-frequency patterns to improve both image acquisition time and the performance of gradient-based optical flow motion analysis methods. This paper explores the effects of three factors-image prefiltering, multiresolution optical flow, and multifrequency tag patterns through a serious of controlled simulation experiments. We show that use of image prefiltering in a multiresolution optical flow approach achieves significant performance gains, and permits a factor of four reduction in imaging time, without the need for multifrequency tag patterns.

关键词： Motion estimation image motion analysis Heart Magnetic resonance imaging Humans Frequency Motion analysis Optical control image resolution Performance gain

来源：评论

学校读者我要写书评

暂无评论

Efficient coding by neuro-fuzzy clustering in vector quantization of wavelet decomposed signals

Efficient coding by neuro-fuzzy clustering in vector quantiz...

引用

Conference of the North American Fuzzy Information Processing Society - NAFIPS

作者： S. Mitra S. Pemmaraju Computer Vision and Image Analysis Laboratory Department of Electrical Engineering Texas Tech University Lubbock TX USA

Multiresolution representation of wavelets in image decomposition and coding shows potential of developing an efficient image compression technique with minimum distortion when vector quantization (VQ) is used. This paper presents a multiresolution and adaptive approach to VQ codebook generation by employing a fuzzy distortion measure embedded in a self-organizing neural network ensuring fast convergence and minimum distortion. Multiresolution codebooks are generated for the wavelet decomposed images using neuro-fuzzy clustering algorithms resulting in significant improvement in the coding process. The signal transformation and vector quantization stages together yield at least, 64:1 bit rate reduction with good visual quality and acceptable peak signal to noise ratio and mean square error. The performance of this new VQ coding technique has been compared to that of the well-known Linde, Buzo, and Gray-VQ for a variety of image classes. In each case, the new VQ technique demonstrated superior ability for fast convergence with minimum distortion at similar bit rate reduction than the existing VQ techniques.

关键词： Vector quantization image coding Signal resolution image resolution Distortion measurement Convergence Bit rate image decomposition Fuzzy neural networks Neural networks

来源：评论

学校读者我要写书评

暂无评论

Efficient image coding using multiresolution wavelet transform and vector quantization

Efficient image coding using multiresolution wavelet transfo...

引用

IEEE Southwest Symposium on image analysis and Interpretation

作者： S. Pemmaraju S. Mitra Computer Vision and Image Analysis Laboratory Department of Electrical Engineering Texas Tech University Lubbock TX USA

image compression forms the backbone for several applications such as storage of images in a database, picture archiving, TV and facsimile transmission, and video conferencing. Compression of images involves taking advantage of the redundancy in data present within an image. A fundamental goal of image compression is to reduce the bit rate for transmission and storage while maintaining an acceptable fidelity or image quality. Existing VQ algorithms however, suffer from a number of practical problems, e.g. codebook initialization, long search process, and getting trapped in local minima. This paper presents an adaptive vector quantization algorithm which uses a neuro-fuzzy clustering technique for optimizing the distortion measure. The fuzzy approach forms the basis for accurately optimizing each codevector by determining the fuzzy centroid of each class. In addition, a multiresolution wavelet decomposition scheme is adopted to make the image better suited for compression and to enable its progressive transmission.

关键词： image coding image resolution Wavelet transforms image storage Clustering algorithms Spine image databases TV Facsimile Videoconference

来源：评论

学校读者我要写书评

暂无评论

A high-speed high-density array-multiplier-accumulator for digital signal processing

引用

ELECTRONICS AND communications IN JAPAN PART II-ELECTRONICS 1996年第2期79卷 86-97页

作者： Minami, T Kasai, R Matsuda, H Kusaba, R Member NTT LSI Laboratories Atsugi Japan 243-01 Graduated in 1980 from the Department of Electrical Engineering Kyushu University where he received his Master's degree in 1982 and joined NTT. Until March 1986 he was engaged in the development of application software for electronic switching systems. He then engaged in research and development of LSIs for image signal processing. At present he is Senior Research Engineer Advanced LSI Laboratory NTT LSI Laboratories. He is a member of IEEE. Graduated in 1972 from the Department of Electrical Engineering Osaka University where he received his Master's degree in 1974 and his Ph.D. in 1992. He joined NTT in 1974. He is engaged in research and development of analysis of MOS devices and design of ASIC for communication. At present he is Executive Research Engineer Advanced LSI Laboratory NTT LSI Laboratories. He is a member of IEEE. Graduated in 1987 from the Department of Communications Tohoku University where he received his Master's degree in 1989 and joined NTT. He is engaged in research and development of high-speed design for image processing LSIs. At present he is Research Engineer Advanced LSI Laboratory NTT LSI Laboratories. He is a member of the Information Processing Society. Graduated in 1985 from the Department of Electrical Engineering Keio University where he received his Master's degree in 1987 and joined NTT. He is engaged in CAD research. At present he is Senior Research Engineer Advanced LSI Laboratory NTT LSI Laboratories. He is a member of the Information Processing Society and IEEE.

This paper discusses the downsizing and speed improvement of short-word multiplier-accumulators, which are frequently used in digital signal processors. As a first step, the optimal configuration for an array-type carry-save adder is considered where the shortest path in the full-adder is used to propagate the sum signal and the carry signal is sent to the full-adder of the two lower stages by skipping a stage. A configuration of the full-adder suitable for the structure is proposed. The case of eight partial product additions shows that the delay can be reduced by 22 percent compared to a simple array-type carry-save adder. Then the short-word carry look-ahead adder using the pass-transistor logic is considered. It is shown that a single-stage carry look-ahead circuit with a four-bitwise iterative structure exhibits nearly the same delay as a two-stage carry look-ahead circuit. In other words, the former is better suited to downsizing. This paper intends to examine the effectiveness of the foregoing new array-type carry-save adder and the single-stage carry look-ahead circuit using the 0.5-mu m CMOS technology. A 16-bit x 14-bit + 31-bit multiplier-accumulator has been designed and is evaluated for cases where the array-type carry-save adder is used to handle accumulation as well as partial products. The resulting area and delay are 0.77 x 0.78 mm(2) and 6.8 ns, respectively. The effectiveness of the approach used in this paper is evaluated by constructing a multiplier-accumulator, but the method is also useful in constructing a multiplier.

关键词： product-sum operation array multiplier carry-save adder full-adder carry look-ahead adder

来源：评论

学校读者我要写书评

暂无评论

Searching for patterns in remote sensing image databases using neural networks

Searching for patterns in remote sensing image databases usi...

引用

IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： J.D. Paola R.A. Schowengerdt Digital Image Analysis Laboratory Department of Electrical and Computer Engineering University of Arizona Tucson Tucson AZ USA

The authors have investigated a method, based on a successful neural network multispectral image classification system, of searching for single patterns in remote sensing databases. While defining the pattern to search for and the feature to be used for that search (spectral, spatial, temporal, etc.) is challenging, a more difficult task is selecting competing patterns to train against the desired pattern. Schemes for competing pattern selection, including random selection and human interpreted selection, are discussed in the context of an example detection of dense urban areas in Landsat Thematic Mapper imagery. When applying the search to multiple images, a simple normalization method can alleviate the problem of inconsistent image calibration. Another potential problem, that of highly compressed data, was found to have a minimal effect on the ability to detect the desired pattern. The neural network algorithm has been implemented using the PVM (Parallel Virtual Machine) library and nearly-optimal speedups have been obtained that help alleviate the long process of searching through imagery.

关键词： Remote sensing image databases Neural networks Multispectral imaging Spatial databases Humans Urban areas Satellites Calibration image coding

来源：评论

学校读者我要写书评

暂无评论

The effect of lossy image compression on image classification

The effect of lossy image compression on image classificatio...

引用

IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： J.D. Paola R.A. Schowengerdt Digital Image Analysis Laboratory Department of Electrical and Computer Engineering University of Arizona Tucson Tucson AZ USA

The authors have classified four different images, under various levels of JPEG compression, using the following classification algorithms: minimum-distance, maximum-likelihood, and neural network. The training site accuracy and percent difference from the original classification were tabulated for each image compression level, with maximum-likelihood showing the poorest results. In general, as compression ratio increased, the classification retained its overall appearance, but much of the pixel-to-pixel detail was eliminated. The authors also examined the effect of compression on spatial pattern detection using a neural network.

关键词： image coding image classification Transform coding Neural networks Discrete cosine transforms Remote sensing Classification algorithms image storage Discrete transforms Quantization

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：