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IEEE International conference on Acoustics, Speech, and Signal processing

作者： Durand, S Froment, J CMLA Ecole Normale Super Cachan F-94235 Cachan France

ISBN: (纸本)0780370414

Recent years have seen the development of signal denoising algorithms based on wavelet transform. It has been shown that thresholding the wavelet coefficients of a noisy signal allows to restore the smoothness of the original signal. However, wavelet denoising suffers of a main drawback : around discontinuities the reconstructed signal is smoothed, exhibiting pseudo-Gibbs phenomenon. We consider the problem of denoising piecewise smooth signals with sharp discontinuities. We propose to apply a traditional wavelet denoising method and to restore the denoised signal using a total variation minimization approach. This second step allows to remove the Gibbs phenomena and therefore to restore sharp discontinuities, while the other structures are preserved. The main innovation of our algorithm is to constrain the total variation minimization by the knowledge of the remaining wavelet coefficients. In this way, we make sure that the restoration process does not deteriorate the information that has been considered as significant in the denoising step. With this approach we substantially improve the performance of classical wavelet denoising algorithms, both in terms of SNR and in terms of visual artifacts.

关键词： Signal processing

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Estimation of large-amplitude motion and disparity fields:: Application to intermediate view reconstruction

Estimation of large-amplitude motion and disparity fields:: ...

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conference on visual communications and image processing 2001

作者： Kardouchi, M Konrad, J Vázquez, C INRS Telecommun Montreal PQ H5A 1C6 Canada

ISBN: (纸本)0819439886

This paper describes a method for establishing dense correspondence between two images in a video sequence (motion) or in a stereo pair (disparity) in case of large displacements. In order to deal with large-amplitude motion or disparity fields, multi-resolution techniques such as blocks matching and optical flow have been used in the past. Although quite successful, these techniques cannot easily cope with motion/disparity discontinuities as they do not explicitly exploit image structure. Additionally, their computational complexity is high;block matching requires examination of numerous vector candidates while optical flow-based techniques are iterative. In this paper, we propose a new approach that addresses both issues. The approach combines feature matching with Delaunay triangulation, and thus reliable long-range correspondences result while the computational complexity is not high (sparse representation). In the proposed approach, feature points are found first using a simple intensity corner detector. Then, correspondence pairs between two images are found by maximizing cross-correlation over a small window. Finally, the Delaunay triangulation is applied to the resulting points, and a dense vector held is computed by planar interpolation over Delaunay triangles. The resulting vector field is continuous everywhere, and thus does not reflect motion or depth discontinuities at object boundaries. In order to improve the rendition of such discontinuities, we propose to further divide Delaunay triangles whenever the displacement vectors within a triangle do not allow good intensity match. The approach has been extensively tested on stereoscopic images in the context of intermediate view reconstruction where the quality of estimated disparity fields is critical for final image rendering. The first results are very encouraging as the reconstructed images are of high quality, especially at object boundaries, and the computational complexity is lower than that of mult

关键词： motion estimation disparity estimation optical flow feature correspondence Delaunay triangulation stereoscopic image processing intermediate view reconstruction

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Interactive browsing of 3D environment over the Internet

Interactive browsing of 3D environment over the Internet

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conference on visual communications and image processing 2001

作者： Zhang, C Li, J Carnegie Mellon Univ Dept Elect & Comp Engn Pittsburgh PA 15213 USA

ISBN: (纸本)0819439886

In this paper, we describe a system for wandering in a realistic environment over the Internet. The environment is captured by the concentric mosaic, compressed via the reference block coder (RBC), and accessed and delivered over the Internet through the virtual media (Vmedia) access protocol. Capturing the environment through the concentric mosaic is easy. We mount a camera at the end of a level beam, and shoot images as the beam rotates. The huge dataset of the concentric mosaic is then compressed through the RBC, which is specifically designed for both high compression efficiency and just-in-time (JIT) rendering. Through the JIT rendering function, only a portion of the RBC biostream is accessed, decoded and rendered for each virtual view. A multimedia communication protocol - the Vmedia protocol, is then proposed to deliver the compressed concentric mosaic data over the Internet. Only the bitstream segments corresponding to the current view are streamed over the Internet. Moreover, the delivered bitstream segments are managed by a local Vmedia cache so that frequently used bitstream segments need not be streamed over the Internet repeatedly, and the Vmedia is able to handle a RBC bitstream larger than its memory capacity. A Vmedia concentric mosaic interactive browser is developed where the user can freely wander in a realistic environment, e.g., rotate around, walk forward/backward and sidestep, even under a tight bandwidth of 33.6 kbps.

关键词： virtual reality image based rendering (IBR) concentric mosaic reference block coder (RBC) virtual media (Vmedia) access protocol just-in-time (JIT) rendering interactive browsing cache

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visualization and navigation in image database applications based on MPEG-7 descriptors

Visualization and navigation in image database applications ...

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IEEE International conference on image processing

作者： T. Sikora Heinrich-Hertz-Institute of Communications Technology Germany

Summary form only given, as follows. The MPEG-7 standard is currently being developed to specify standardized interfaces that help users or agents to identify, filter, browse and efficiently retrieve audio-visual material. The purpose of the presentation is to provide an overview of the scope and potential of the MPEG-7 standard, with particular emphasis on no-text descriptors for visual content. Based on the MPEG-7 specifications, the implementation of a wealth of applications is possible. Various application scenarios are presented and discussed.

关键词： visualization Navigation image databases MPEG 7 Standard communications technology Communication standards Standards development Filters

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Video summarization with minimal visual content redundancies

Video summarization with minimal visual content redundancies

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IEEE International conference on image processing

作者： Y. Gong X. Liu C&C Research Laboratories NEC USA Inc. San Jose CA USA

We propose a video summarization method able to produce a motion video summary that minimizes the visual content redundancy for the input video. We derive the visual content redundancy metric that tells how much redundancy a video contains, and how much the video can be curtailed without losing too much visual content. Then we develop a method that produces a summary of the input video with the minimal redundancy measured. The video summary also contains the original audio segments that are partially synchronized with the summarized visual content. The experimental evaluations show the effectiveness of the redundancy metric and the summarization method.

关键词： image segmentation Humans Video sequences Laboratories National electric code Computer networks Communication networks Information processing communications technology Watches

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From cross-country autonomous navigation to intelligent deep space communications: visual sensor processing at JPL

From cross-country autonomous navigation to intelligent deep...

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International conference on image Analysis and processing

作者： R. Manduchi L. Matthies F. Pollara Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA

We describe ongoing work at JPL in two fields: autonomous navigation for terrestrial vehicles, and prioritized progressive transmission for deep space communications. While such applications may seem rather disparate, they have in common the need for autonomous reasoning about visual information. We first review a number of techniques currently under development that make use of data from color and infrared cameras, multispectral sensors, and laser rangefinder for estimating properties of the terrain cover in outdoor vegetated terrain. We then discuss how onboard visual analysis mechanisms for Mars rovers can be used for prioritizing the data to be transmitted to Earth, in order to maximize the science return of a mission.

关键词： Intelligent sensors Infrared sensors Mars Space technology Aircraft navigation Propulsion Laboratories Cameras Geoscience NASA

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2nd IEEE Pacific Rim conference on Multimedia, PCM 2001

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2nd IEEE Pacific-Rim conference on Multimedia, IEEE-PCM 2001

ISBN: (纸本)3540426809

The proceedings contain 157 papers. The special focus in this conference is on Wearable Computing, Retrieval Techniques, Coding Techniques and Systems. The topics include: Hardware platform for wearable computing research;automatic summarization of wearable video indexing subjective interest;a novel video retrieval method to support a user's recollection of past events aiming for wearable information playing;experience of immersive virtual world using cellular phone interface;toward human-centered interaction through wearable vision and visualization;face indexing and retrieval in personal digital album;an image retrieval system based on local and global color descriptors;a new shot boundary detection algorithm;an adaptive index structure for high-dimensional similarity search;combining hierarchical classifiers with video semantic indexing systems;dynamic multi-reference prediction in video coding for improved error resilience over internet;fast and robust sprite generation for mpeg-4 video coding;improved mpeg-4 visual texture coding using perceptual dithering for transparent image coding;a real-time large vocabulary continuous recognition system for Chinese sign language;object modeling, coding, and transmission for multimedia communications;live events accessing for multi-users with free viewpoints using stereo Omni-directional system;user modeling for efficient use of multimedia files;a feature-based vehicle tracking system in congested traffic video sequences;movie event detection by using audiovisual information;automatic segmentation and tracking of moving objects;interacting with 3d graphic objects in an image-based environment and robust head pose estimation using textured polygonal model with local correlation measure.

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A feedback system for graphics video coding and networking

A feedback system for graphics video coding and networking

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

作者： Dongmei Wang R.M. Mersereau Agere Systems StarCore Technology Center Atlanta GA USA Center for Signal and Image Processing Georgia Institute of Technology Atlanta GA USA

This paper presents feedback design of a desktop visual communications system. The system consists of video coding using a 3-D graphics model and video transmission over the Internet. To reduce the overall video quality degradation in visual communications caused by coding and networking errors, we jointly researched the compression and transmission of video signals. In building the 3-D graphics model-based coding structure, instead of using feedforward based on pixel intensity, we develop a three-level signal representation and an analysis-by-synthesis feedback framework. In prototyping the video over IP in desktop conferencing, we adapt the video encoders coding rates based on feedback of the network states and receivers. We therefore contribute to the analysis, modeling, and transmission of multimedia signals for desktop visual communications.

关键词： Feedback Graphics Video coding Video compression visual communication Videoconference Signal analysis Internet Degradation Buildings

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Name block location in facsimile images using spatial/visual cues

Name block location in facsimile images using spatial/visual...

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International conference on Document Analysis and Recognition

作者： L. Likforman-Sulem Ecole Nationale Supérieure des Télécommunications Signal and Image Processing Laboratory and CNRS LTCI Paris France

We discuss the name block location process of a messaging system which deals with facsimile images including handwritten items. This process is the first stage of an information extraction task which aims at extracting condensed information from such documents. The approach is based on the use of spatial/visual cues for selecting regions in the image where sender and recipient information can be found. These cues are based on the human visual grouping process. The start of the process is the binary image and its electronic version produced by an OCR system. A document processing stage first extracts layout components at a pseudo word level and detects handwritten components. The electronic version enables the selection of layout components including predefined printed keywords. These layout components are then grouped under spatial constraints to initialize a logical description. The logical objects searched for are the main field headers relative to the sender and the recipient and the sender name. Experimental results on the performance of the approach are presented.

关键词： Facsimile Data mining Electronic mail Humans Content based retrieval Signal processing image processing Laboratories Optical character recognition software Speech processing

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Special section on storage, processing, and retrieval of digital media

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JOURNAL OF ELECTRONIC IMAGING 2001年第4期10卷 833-834页

作者： Yeung, MM Li, CS Lienhart, R Yeo, BL Intel Corp Microprocessor Res Labs Santa Clara CA 95052 USA IBM Thomas J Watson Res Ctr Hawthorne NY 10532 USA Teracent Corp Cupertino CA 95014 USA

Recent advances in computing and communications are leading to the creation of large-scale databases of visual and multimedia information. Such databases are finding ready applications in a wide range of fields such as advertising and marketing, education and training, entertainment, medicine, and remote sensing. Because of the very nature of visual and multimedia data, new and innovative methods are called for in modeling, processing, organizing and indexing of this data for efficient storage, management, access, and delivery of the content. The goal of this special section is to highlight the new research areas and explore technology frontiers, by soliciting and selecting quality papers addressing issues from various aspects of storage, search, retrieval, and processing of digital media data (video/image/audio) and across a wide range of research disciplines. For this special section, we have solicited papers in relevant areas, ranging from content capture and processing, database management, new results on similarity measures and semantic features, and query methods to multimedia systems embracing leading-edge technology, and special applications of media management, retrieval, and processing across multiple fields, from consumer media systems, digital libraries, and media imaging to remote sensing. We encouraged the authors of some very promising papers in the SPIE/IS&T Electronic Imaging Symposium (San Jose) 2001 conference on Storage and Retrieval of Media Databases to submit a full journal-quality version of their conference manuscript to this special section. We also received submissions from outside of the conference, in response to our general call for papers. All submitted papers have undergone multiple peer-reviews, and we accepted 12 papers after two rounds of revisions and follow-up reviews. We have classified the 12 papers into four major categories: (A) Content-based image Retrieval (the first two papers), (B) Content-based Video Retrieval (the next

关键词： Multimedia systems

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