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IEEE International conference on image processing

作者： A. Tomita T. Echigo M. Knrokawa H. Miyamori S. Iisaku Tokyo Research Laboratory IBM Research Japan Communications Research Laboratory Ministry of Posts and Telecommunications Japan

A visual tracking system is presented in which a combination of techniques is used to obtain motion features of objects from a video sequence. Further processing of the motion features gives the spatio-temporal trajectories of the objects, that can be used as cues for annotation. The system solves problems found in tracking objects in unconstrained environments, such as in sports games, where there are multiple objects in motion, the camera performs pan, tilt and zoom movements, and there are objects other than the players in the background. Coarse segmentation is performed with multi-class statistical color models, constructed from samples of the representative colors of each team. Motion vectors are computed to find region correspondence between consecutive frames. Background elements are eliminated by using camera motion parameters, and other false matches are detected by analyzing motion pattern consistency. Finally, objects are registered by placing windows centered in each tracked region. An experimental realization was used to test the system for tracking players in a soccer game, but it could had also been used for generating annotation cues of videos from other sports as well.

关键词： Tracking Video sequences Cameras Games Motion analysis image segmentation Pattern matching Motion detection Pattern analysis System testing

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On the necessary density for spectrum-blind nonuniform sampling subject to quantization

On the necessary density for spectrum-blind nonuniform sampl...

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International conference on Acoustics, Speech, and Signal processing (ICASSP)

作者： M. Gastpar Y. Bresler Swiss Federal Institute of Technology Audio Visual Communications Laboratory Lausanne Switzerland

It is known that in the absence of distortion, the necessary sampling density for a multiband signal is given by its spectral occupancy. However, in general, the samples have to be acquired nonuniformly. There exist sampling patterns such that reconstruction is feasible even if the actual spectral support of the multiband signal is not known. If the samples are distorted, an increased sampling density may lead to a superior performance. In this paper, we consider the case of small distortion due to fine quantization of the samples, and we derive a necessary condition on the optimal sampling density.

关键词： Nonuniform sampling Quantization Sampling methods image reconstruction Discrete Fourier transforms Distortion Frequency domain analysis Magnetic resonance imaging visual communication Laboratories

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Texture modeling and classification in wavelet feature space

Texture modeling and classification in wavelet feature space

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IEEE International conference on image processing

作者： M.N. Shirazi H. Noda N. Takao Communications Research Laboratories Kobe Japan Kyushu Institute of Technology Kitakyushu Japan

ISBN: (纸本)0780362977

One difficulty of texture analysis and classification in the past was the lack of adequate tools to characterize textures over different scales. Previous developments in multiresolution analysis, such as the wavelet transform, promise ways to overcome this difficulty. We present a texture classification algorithm based on Markov modeling of intrascale and interscale statistical regularities of textures in the wavelet domain. The model provides an accurate multiscale texture representation and underlies a classification algorithm with a high classification rate.

关键词： Wavelet transforms Frequency Classification algorithms Wavelet analysis Statistical distributions Wavelet packets Multiresolution analysis Wavelet domain visual system Face recognition

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Human perception of mismatched stereoscopic 3D inputs

Human perception of mismatched stereoscopic 3D inputs

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IEEE International conference on image processing

作者： L.B. Stelmach W.J. Tam D.V. Meegan A. Vincent P. Corriveau Communications Rcscarch Centre Ottawa Canada

ISBN: (纸本)0780362977

The bandwidth required to transmit stereoscopic video images is nominally twice that required for standard, monoscopic images. One method of reducing the required bandwidth is to code the two video streams asymmetrically. We assessed the perceptual impact of this bandwidth-reduction technique for low-pass filtering, DCT-based quantization, and a combination of filtering and quantization. It was found that the binocular percept depended on the type of degradation: for low-pass filtering, the binocular percept was dominated by the high-quality image, whereas for quantization it corresponded to the average of the inputs to the two eyes. The results indicated that asymmetrical coding is a promising technique for reducing storage and transmission bandwidth of stereoscopic sequences.

关键词： Humans Quantization Degradation Low pass filters Filtering Testing Bandwidth Eyes image coding visual system

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IEEE International conference on image processing

作者： M.N. Do M. Vetterli Laboratory for Audio-visual Communications Swiss Federal Institute of Technology Lausanne Switzerland Department of EECS University of California Berkeley Berkeley CA USA

The focus of this work is on using texture information for searching, browsing and retrieving images from a large database. In the wavelet approaches, texture is characterized by its energy distribution in the decomposed subbands. However it is unclear on how to define similarity functions on extracted features; usually simple norm-based distances together with heuristic normalization are employed. We develop a novel wavelet-based texture retrieval method that is based on the modeling of the marginal distribution of wavelet coefficients using the generalized Gaussian density (GGD) and a closed form Kullback-Leibler distance between the GGDs. The proposed method provides greater accuracy and flexibility in capturing texture information while its simplified form has close resemblance with existing methods. Experimental results indicate that the new method significantly improves retrieval rates, e.g. from 65% to 77%, against traditional approaches while it has comparable levels of computational complexity.

关键词： Feature extraction image databases Spatial databases image retrieval Maximum likelihood estimation Information retrieval Data mining Iron Samarium Filter bank

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Indexing spatial content of still texture in MPEG-4

Indexing spatial content of still texture in MPEG-4

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European Signal processing conference (EUSIPCO)

作者： Jayank Bhalod V Mohammed Zubair S. Panchanathan Visual Computing and Communications Laboratory Department of Computer Science and Engineering Arizona State University Tempe - Arizona USA

There has been a rapid increase in audio-visual information in digital form with the ever-increasing popularity of the Internet. The Moving Pictures Expert Group has recently presented a video compression and content manipulation standard, called MPEG-4 [1]. This was developed in response to the growing need for a coding method that can facilitate access to visual objects in natural and synthetic moving pictures in a wide variety of applications. In this paper, we propose a method for indexing the spatial content of Still Texture in MPEG-4 Video. There has been a number of approaches proposed recently [1],[3],[5],[6], which address content based indexing using features such as, color, shape and/or texture. We note that the still texture information is encoded using Wavelet Transform in MPEG-4. Since still texture can have an arbitrary shape, we propose to employ a combination of shape, color and texture features. The shape features are derived from the alpha plane and represented using Cubic B-spline approximation. The color and texture features are extracted directly from the wavelet compressed domain. An important attribute of the proposed approach is also the introduction of the novel concept of “containment” of spatial features for content based indexing.

关键词： Shape image color analysis Transform coding Indexing Splines (mathematics) Feature extraction Vectors

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A system for the automatic extraction of 3-D facial feature points for face model calibration

A system for the automatic extraction of 3-D facial feature ...

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IEEE International conference on image processing

作者： Yong Yan K. Challapali Video Communications Department Philips Research Briarcliff Manor NY USA

The emergence of the MPEG-4 standard has facilitated the development of new approaches to very-low bitrate coding, including model-based coding for human faces. As a tool in the synthetic/natural hybrid coding part of the standard, a face object is defined in terms of its shape-consisting of a set of facial feature points and texture. In addition, this face object can be animated by controlling these facial feature points to obtain a visual manifestation of speech and facial expression. However, the extraction of these facial feature points based on a particular human face is not a trivial task, and lies outside the scope of the MPEG-4 standard. In this paper, we introduce a system that automatically extracts 3-D facial feature points and calibrates a generic face model to a particular speaker's face. Our approach differs from previous work in that we extract facial feature points in 3-D using a stereoscopic camera leading to an automatic robust calibration of the face model to the particular face. Preliminary experimental results show promising performance.

关键词： Facial features Calibration Facial animation MPEG 4 Standard Humans Face Standards development Bit rate Speech Cameras

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Low-bit-rate scalable compression of mobile wireless video

Low-bit-rate scalable compression of mobile wireless video

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IEEE Region 10 International conference TENCON

作者： R. Fakeh A.A.A. Ghani M.Y.M. Saman A.R. Ramli Faculty of Computer Science and Information Technology Universiti Putra Malaysia Serdang Malaysia Deptartment Of Computer & Communication Systems Engineering Faculty of Engineering Universiti Putra Malaysia Serdang Selangor Darul Ehsan Malaysia

Low bit rate video coding has triggered intensive research in both academia and industry. To address the problem of heterogeneity, and meeting a very small bandwidth of mobile wireless networks, low bit rate scalable video compression is becoming more important. This paper discusses the current approach to wireless visual communications for the need of low bit rate scalable video compression, using discrete wavelet transform techniques. The discrete wavelet transform (DWT) has provided an efficient framework of multiresolution space-frequency representation with promising applications in image processing. This codec is based on 3D wavelet coding and adaptive quantization of the subbands coefficients. A common problem with some existing quantization methods is that the inherent image structures are severely distorted with course quantization. The Moving Picture Expert Group-4 (MPEG-4), an important component of the ITU standard is referred to as the benchmark of video standards for low bit rate video transmission.

关键词： Video compression Discrete wavelet transforms Bit rate Quantization image coding Video coding Bandwidth Wireless networks Wireless communication visual communication

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Low delay foveated visual communications over wireless channels

Low delay foveated visual communications over wireless chann...

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International conference on image processing (ICIP'99)

作者： Lee, Sanghoon Bovik, Alan C. Kim, Young Yong Univ of Texas at Austin Austin United States

The great potential of `foveated imaging' lies in the entropy reduction relative to the original image while minimizing the loss of visual information. Utilizing human foveation combined with video compression, as well as communication and human-machine interface techniques, more efficient multimedia services are expected to be provided in the near future. In this paper, we introduce a prototype for foveated visual communications as one of future human interactive multimedia applications, and demonstrate the benefit of the foveation over fading statistics in the downtown area of Austin, Texas. In order to compare the performance with regular video, we use spatial/temporal resolution and source transmission delay as the evaluation criteria.

关键词： image communication systems

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Estimation of feature parameters in model-based image coding system for video conference

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Proceedings of SPIE - The International Society for Optical Engineering 1999年第I期3653卷 465-472页

作者： Yu, Lu Liu, Yunhai Yao, Qingdong Zhejiang Univ Hangzhou China

Model-based image coding is a well-known solution for image communication at very low bit-rate. But very complex techniques and large amount of computation are involved in these systems. It is especially difficult to automatically extract Facial Definition Parameters (FDPs) and Facial Animation Parameters (FAPs), which are demed in MPEG-4, from 2D image to represent 3D moving objects. In this paper, an algorithm using intra- and inter-frame information to estimate feature parameters is proposed. It utilizes spatial information (edge information) as well as temporal difference between successive frames. The combination using of 2 kinds of information makes the system more robust. Physiological symmetry and proportion is another kind of knowledge used here to make the system to less computational intenseness.

关键词： image coding

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