检索结果-内蒙古大学图书馆

Conference on visual communications and image processing 2004

作者： Said, A Hewlett Packard Labs Cupertino CA 95014 USA

ISBN: (纸本)0819452114

It is possible to improve the features supported by devices with embedded systems by increasing the processor computing power, but this always results in higher costs, complexity, and power consumption. An interesting alternative is to use the growing networking infrastructures to do remote processing and visualization, with the embedded system mainly responsible for communications and user interaction. This enables devices to behave as if much more "intelligent" to users, at very low costs and power. In this article we explain how compression can make some of these solutions more bandwidth-efficient, enabling devices to simply decompress very rich graphical information and user interfaces that had been rendered elsewhere. The mixture of natural images and video with text, graphics, and animations simultaneously in the same frame is called compound video. We present a new method for compression of compound images and video, which is able to efficiently identify the different components during compression, and use an appropriate coding method. Our system uses lossless compression for graphics and text, and, on natural images and highly detailed parts, it uses lossy compression with dynamically varying quality. Since it was designed for embedded systems with very limited resources, and it has small executable size, and low complexity for classification, compression and decompression. Other compression methods (e.g., MPEG) can do the same, but are very inefficient for compound content. High-level graphics languages can be bandwidth-efficient, but are much less reliable (e.g., supporting Asian fonts), and are many orders of magnitude more complex. Numerical tests show the very significant gains in compression achieved by these systems.

关键词： embedded systems image and video coding mixed raster content remote visualization

来源：评论

学校读者我要写书评

暂无评论

Error-resilient video coding performance analysis of motion JPEG 2000 and MPEG-4

Error-resilient video coding performance analysis of motion ...

引用

Conference on visual communications and image processing 2004

作者： Dufaux, F Ebrahimi, T Swiss Fed Inst Technol Signal Proc Inst Lausanne Switzerland

ISBN: (纸本)0819452114

The new Motion JPEG 2000 standard is providing with some compelling features. It is based on an intra-frame wavelet coding. which makes it very well suited for wireless applications. Indeed, the state-of-the-art wavelet coding scheme achieves very high coding efficiency. In addition, Motion JPEG 2000 is very resilient to transmission errors as frames are coded independently (intra coding). Furthermore, it requires low complexity and introduces minimal coding delay. Finally, it supports very efficient scalability. In this paper, we analyze the performance of Motion JPEG 2000 in error-prone transmission. We compare it to the well-known MPEG-4 video coding scheme, in terms of coding efficiency, error resilience and complexity. We present experimental results which show that Motion JPEG 2000 outperforms MPEG-4 in the presence of transmission errors.

关键词： JPEG2000 Video Wavelets Video coding Computer programming Error analysis image compression Motion analysis Video compression Standards development

来源：评论

学校读者我要写书评

暂无评论

Block based embedded color image and video coding

Block based embedded color image and video coding

引用

Conference on visual communications and image processing 2004

作者： Nagaraj, N Pearlman, WA Islam, A GE Global Res John F Welch Technol Ctr Bangalore Karnataka India

ISBN: (纸本)0819452114

Set Partitioned Embedded bloCK coder (SPECK) has been found to perform comparable to the best-known still grayscale image coders like EZW, SPIHT, JPEG2000 etc. In this paper, we first propose Color-SPECK (CSPECK), a natural extension of SPECK to handle color still images in the YUV 4:2:0 format. Extensions to other YUV formats are also possible. PSNR results indicate that CSPECK is among the best known color coders while the perceptual quality of reconstruction is superior than SPIHT and JPEG2000. We then propose a moving picture based coding system called Motion-SPECK with CSPECK as the core algorithm in an intra-based setting. Specifically we demonstrate two modes of operation of Motion-SPECK, namely the constant-rate mode where every frame is coded at the same bit-rate and the constant-distortion mode, where we ensure the same quality for each frame. Results on well-known CIF sequences indicate that Motion-SPECK performs comparable to Motion-JPEG2000 while the visual quality of the sequence is in general superior. Both CSPECK and Motion-SPECK automatically inherit all the desirable features of SPECK such as embeddedness, low computational complexity, highly efficient performance, fast decoding and low dynamic memory requirements. The intended applications of Motion-SPECK would be high-end and emerging video applications such as High Quality Digital Video Recording System, Internet Video, Medical Imaging etc.

关键词： image coding video coding compression color coding embedded Motion-JPEG2000 wavelet intra-based coding moving picture coding

来源：评论

学校读者我要写书评

暂无评论

Transversal versus lifting approach to motion-compensated temporal discrete wavelet transform of image sequences: equivalence and tradeoffs

Transversal versus lifting approach to motion-compensated te...

引用

Conference on visual communications and image processing 2004

作者： Konrad, J Boston Univ Dept Elect & Comp Engn Boston MA 02215 USA

ISBN: (纸本)0819452114

Lifting-based implementations of various discrete wavelet transforms applied in the temporal direction under motion compensation have recently become a very powerful tool in video compression research. We present in this paper a theoretical analysis of motion compensation in both transversal and lifted implementations of such transforms. We derive conditions for perfect reconstruction in the case of motion-compensated transversal discrete wavelet transform. We also derive conditions on motion transformation assuring that a motion-compensated lifting scheme is exactly equivalent to its transversal counterpart. In general, these conditions require that motion transformation allow composition and be invertible. Unfortunately, many motion models do not obey these properties, thus inducing subband decomposition errors (prior to compression). We propose an alternative approach to motion compensation in the case of Haar transform. This new approach poses no constraints on motion;motion-compensated lifted Haar transform exactly implements its transversal implementation, and the latter obeys perfect reconstruction, both regardless of motion transformation used. This new approach, however, does not extend to the 5/3 or any higher-order discrete wavelet transform.

关键词： motion compensation temporal discrete wavelet transform (DWT) lifted DWT transversal DWT lifting steps image sequence coding

来源：评论

学校读者我要写书评

暂无评论

Multi-spectral image fusion based on fractal features

Multi-spectral image fusion based on fractal features

引用

visual communications and image processing 2004

作者： Tian, Jie Chen, Jie Zhang, Chunhua Institute of Acoustic Chinese Academy of Science Beijing 100080 China Dept. of Automatic Control Beijing Institute of Technology Beijing 100081 China

image fusion has been one of the main technical routines used to detect and recognize objects from images. Loss of information is unavoidable in fusion process. So it is very important contents of image fusion how to avoid the loss of useful information or how to preserve features which are helpful to the detection. In consideration of these issues and the fact that most detection problems are actually to distinguish man-made objects from natural background, a fractal-based multi-spectral fusion algorithm has been developed. Source images are firstly orthogonally decomposed according to wavelet transform theories, then fractal-based detection is held to each decomposed image. After the district containing man-made objects is detected, a special composing operator is adopted to reduce the information loss of man-made objects. This fractal-based algorithm is compared with a common weighted average fusion algorithm and the experimental results imply that the fractal-based multi-spectral fusion algorithm can effectively preserve the information of man-made objects with a high contrast.

关键词： image processing

来源：评论

学校读者我要写书评

暂无评论

Geometric model-based segmentation of the prostate and surrounding structures for image guided radiotherapy

Geometric model-based segmentation of the prostate and surro...

引用

Conference on visual communications and image processing 2004

作者： Tang, XL Jeong, YW Radke, RJ Chen, GTY Rensselaer Polytech Inst ECSE Dept Troy NY 12180 USA

ISBN: (纸本)0819452114

We present a computer vision tool to improve the clinical outcome of patients undergoing radiation therapy for prostate cancer by improving irradiation technique. While intensity modulated radiotherapy (IMRT) allows one to irradiate a specific region in the body with high accuracy, it is still difficult to know exactly where to aim the radiation beam on every day of the 30similar to40 treatments that are necessary. This paper presents a geometric model-based technique to accurately segment the prostate and other surrounding structures in a daily serial CT image, compensating for daily motion and shape variation. We first acquire a collection of serial CT scans of patients undergoing external beam radiotherapy, and manual segmentation of the prostate and other nearby structures by radiation oncologists. Then we train shape and local appearance models for the structures of interest. When new images are available, an iterative algorithm is applied to locate the prostate and surrounding structures automatically. Our experimental results show that excellent matches can be given to the prostate and surrounding structure. Convergence is declared after 10 iterations. For 256 x 256 images, the mean distance between the hand-segmented contour and the automatically estimated contour is about 1.5 pixels (2.44 mm), with variance about 0.6 pixel (1.24 mm).

关键词： shape model appearance model principal component analysis segmentation intensity modulated radiotherapy conformal avoidance

来源：评论

学校读者我要写书评

暂无评论

Selective Bayesian estimation for efficient super-resolution

Selective Bayesian estimation for efficient super-resolution

引用

Fourth IEEE International Symposium on Signal processing and Information Technology, ISSPIT 2004

作者： Ivanovski, Zoran A. Karam, Lina J. Abousleman, Glen P. Department of Electrical Engineering Arizona State Univesity Tempe AZ 85287-5706 Compression Communications and Intelligence Lab. General Dynamics C4 Systems Scottsdale AZ 85257

ISBN: (纸本)0780386892

In this paper, a new approach to efficient and robust super-resolution is presented. Our method is based on selectively applying a Bayesian MAP estimator to image regions with high spatial activity. The degree of spatial activity is measured using the gradient of the estimated high-resolution image at each iteration. In addition, selective filtering is applied to enhance the visual quality of the estimated high-resolution image. The results obtained via simulation and with real video sequences demonstrate up to a 50% reduction in computational complexity, with improved visual quality, and higher SNR gains for magnification factors of four or more. © 2004 IEEE.

关键词： image analysis

来源：评论

学校读者我要写书评

暂无评论

Silhouette and stereo fusion for 3D object modeling

引用

COMPUTER VISION AND image UNDERSTANDING 2004年第3期96卷 367-392页

作者： Esteban, CH Schmitt, F Signal and Image Processing Department CNRS UMR 5141 Ecole Nationale Supérieure des Télécommunications France

In this paper, we present a new approach to high quality 3D object reconstruction. Starting from a calibrated sequence of color images, the algorithm is able to reconstruct both the 3D geometry and the texture. The core of the method is based on a deformable model, which defines the framework where texture and silhouette information can be fused. This is achieved by defining two external forces based on the images: a texture driven force and a silhouette driven force. The texture force is computed in two steps: a multi-stereo correlation voting approach and a gradient vector flow diffusion. Due to the high resolution of the voting approach a multi-grid version of the gradient vector flow has been developed. Concerning the silhouette force, a new formulation of the silhouette constraint is derived. It provides a robust way to integrate the silhouettes in the evolution algorithm. As a consequence, we are able to recover the contour generators of the model at the end of the iteration process. Finally, a texture map is computed from the original images for the reconstructed 3D model. (C) 2004 Elsevier Inc. All rights reserved.

关键词： 3D reconstruction deformable model multigrid gradient vector flow visual hull texture

来源：评论

学校读者我要写书评

暂无评论

Robust image transmission using a new joint source channel coding algorithm and dual adaptive OFDM

Robust image transmission using a new joint source channel c...

引用

Conference on visual communications and image processing 2004

作者： Masoud, F Cho, S Pearlman, WA Rensselaer Polytech Inst Ctr Image Proc Res Dept Elect Comp & Syst Engn Troy NY 12180 USA

ISBN: (纸本)0819452114

In this paper we consider the problem of robust image coding and packetization for the purpose of communications over slow fading frequency selective channels and channels with a shaped spectrum like those of digital subscribe lines (DSL). Towards this end, a novel and analytically based joint source channel coding (JSCC) algorithm to assign unequal error protection is presented. Under a block budget constraint, the image bitstream is de-multiplexed into two classes with different error responses. The algorithm assigns unequal error protection (UEP) in a way to minimize the expected mean square error (MSE) at the receiver while minimizing the probability of catastrophic failure. In order to minimize the expected mean square error at the receiver, the algorithm assigns unequal protection to the value bit class (VBC) stream. In order to minimizes the probability of catastrophic error which is a characteristic of progressive image coders, the algorithm assigns more protection to the location bit class (LBC) stream than the VBC stream. Besides having the advantage of being analytical and also numerically solvable. the algorithm is based on a new formula developed to estimate the distortion rate (D-R) curve for the VBC portion of SPIHT. The major advantage of our technique is that the worst case instantaneous minimum peak signal to noise ratio (PSNR) does not differ greatly from the averge MSE while this is not the case for the optimal single stream (UEP) system. Although both average PSNR of our method and the optimal single stream UEP are about the same, our scheme does not suffer erratic behavior because we have made the probability of catastrophic error arbitarily small. The coded image is sent via orthogonal frequency division multiplexing (OFDM) which is a known and increasing popular modulation scheme to combat ISI (Inter Symbol Interference) and impulsive noise. Using dual adaptive energy OFDM, we use the minimum energy necessary to send each bit stream at a part

关键词： SPIHT OFDM robust image transmission

来源：评论

学校读者我要写书评

暂无评论

Effective quality analysis for video streaming over wireless ad hoc network

Effective quality analysis for video streaming over wireless...

引用

Conference on visual communications and image processing 2004

作者： He, ZH Chen, CW Univ Missouri Dept Elect & Comp Engn Columbia MO 65211 USA

ISBN: (纸本)0819452114

Video encoding and streaming over wireless ad hoc network operates under severe conditions, such as time-varying channel characteristics with bursty errors, limit power for data transmission, and dynamic topology of the self-organized network, stringent time delay for packet delivery, etc. Due to the dynamic topology, complex mechanism, and time-varying nature of the wireless ad hoc network, the network system and the streaming service often exhibit unpredictable behaviors. The ultimate goal in the wireless video streaming service is to provide the end user with the best possible video presentation quality. The video streaming quality, often measured by the end-to-end picture distortion, is affected by the scene coding characteristics S of the input video, and the configuration of the network parameters N which includes bandwidth, transmission power, bit error ratio, delay, etc. This brings up the following important and challenging issue: given an input video with scene characteristics S and a network configuration N, what is the average video streaming quality the receiver could expect the system to provide. To address this issue, in this work, we examine the behaviors and constraints of the major components in the streaming system, and propose an across-layer framework to model, control, and optimize the end-to-end video streaming quality.

关键词： Video Video coding Video compression Distortion Data modeling Video surveillance Computer programming Wireless communications Statistical analysis Data transmission

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：