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IEEE International Conference on Acoustics, Speech, and Signal processing

作者： Zhang, XP Ryerson Polytech Inst Dept Elect & Comp Engn Toronto ON M5B 2K3 Canada

ISBN: (纸本)0780370414

Noise reduction has been a traditional problem in image processing. Recent wavelet thresholding based denoising methods proved promising, since they are capable of suppressing noise while maintaining the high frequency signal details. However, the local space-scale information of the image is not adaptively considered by standard wavelet thresholding methods. In this paper, a new type of thresholding neural networks (TNN) is presented with a new class of smooth nonlinear thresholding functions being the activation function. Unlike the standard soft-thresholding function, these new nonlinear thresholding functions are infinitely differentiable. Then a new nonlinear 2-D space-scale adaptive filtering method based on the wavelet TNN is presented for noise reduction in images. The numerical results indicate that the new method outperforms the Wiener filter and the standard wavelet thresholding denoising method in both peak-signal-to-noise-ratio (PSNR) and visual effect.

关键词： image processing

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Adaptive regularized image interpolation using data fusion and steerable constraints

Adaptive regularized image interpolation using data fusion a...

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Conference on visual communications and image processing 2001

作者： Shin, JH Paik, JK Price, JR Abidi, MA Chung Ang Univ Dept Image Engn Grad Sch Adv Imaging Sci Multimedia & Film Tongjak Ku Seoul 156756 South Korea

ISBN: (纸本)0819439886

This paper presents an adaptive regularized image interpolation algorithm from blurred and noisy low resolution image sequence, which is developed in a general framework based on data fusion. This framework can preserve the high frequency components along the edge orientation in a restored high resolution image frame. This multiframe image interpolation algorithm is composed of two levels of fusion algorithm. One is to obtain enhanced low resolution images as an input data of the adaptive regularized image interpolation based on data fusion. The other one is to construct the adaptive fusion algorithm based on regularized image interpolation using steerable orientation analysis. In order to apply the regularization approach to the interpolation procedure, we first present an observation model of low resolution video formation system. Based on the observation model, we can hare an interpolated image which minimizes both residual between the high resolution and the interpolated images with a prior constraints. In addition, by combining spatially adaptive constraints, directional high frequency components are preserved with efficiently suppressed noise. In the experimental results, interpolated images using the conventional algorithms are shown to compare the conventional algorithms with tile proposed adaptive fusion based algorithm. Experimental results show that the proposed algorithm has the advantage of preserving directional high frequency components and suppressing undesirable artifacts such as noise.

关键词： image interpolation data fusion steerable filter regularization resolution enhancement adaptive edge preserving

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Silhouette and stereo fusion for 3D object modeling

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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

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Video scouting: An architecture and, system for the integration of multimedia information in personal TV applications

Video scouting: An architecture and, system for the integrat...

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IEEE International Conference on Acoustics, Speech, and Signal processing

作者： Jasinschi, RS Dimitrova, N McGee, T Agnihotri, L Zimmerman, J Philips Res Briarcliff Manor NY 10510 USA

ISBN: (纸本)0780370414

Currently available Personal Video Recorders find and store whole TV programs. Our system, Video Scouting, not only finds and stores programs;it automatically segments and indexes story segments from the programs according to viewers' profiles. The extracted descriptions serve the viewers' content information requests for program segment selection, e.g. play the three minute interview with Hillary Clinton. To achieve this, the system combines information from the audio, visual, and transcript domains in a probabilistic framework based on Bayesian networks. In this paper we describe the overall architecture, a system implementation, and discuss some experimental results.

关键词： image retrieval

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Scalable image coding for interactive image communications over networks

Scalable image coding for interactive image communications o...

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visual communications and image processing 2001

作者： Yoon, S.H. Ji Hyun Lee Alexander, W.E. Department of Computer Science North Carolina A and T State Univ. Greensboro NC United States

This paper presents a new, scalable coding technique that can be used in interactive image/video communications over the Internet. The proposed technique generates a fully embedded bit stream that provides scalability with high quality for the whole image and it can be used to implement region based coding as well. The embedded bit stream is comprised of a basic layer and many enhancement layers. The enhancement layers add refinement to the quality of the image that has been reconstructed using the basic layer. The proposed coding technique uses multiple quantizers with thresholds (QT) for layering and it creates a bit plane for each layer. The bit plane is then partitioned into sets of small areas to be coded independently. Run length and entropy coding are applied to each of the sets to provide scalability for the entire image resulting in high picture quality in the user-specific area of interest (ROI). We tested this technique by applying it to various test images and the results consistently show high level of performance.

关键词： image coding

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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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Graphical transformation of multimedia XML documents

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ANNALS OF SOFTWARE ENGINEERING 2001年第1期12卷 119-137页

作者： Zhang, K Zhang, DQ Deng, Y Univ Texas Dept Comp Sci Richardson TX 75083 USA Coral Corp Ottawa ON Canada

As a commonly acceptable standard for guiding Web markup documents, XML allows the Internet users to create multimedia documents of their preferred structures and share with other people. The creation of various multimedia document structures, typically as trees, implies that some kinds of conversion mechanisms are needed for people using different structures to understand each other. This paper presents a visual approach to the representation and validation of multimedia document structures specified in XML and transformation of one structure to another. The underlying theory of our approach is a context-sensitive graph grammar formalism. The paper demonstrates the conciseness and expressiveness of the graph grammar formalism. An example XML structure is provided and its graph grammar representation, validation and transformation to a multimedia representation are presented.

关键词： XML (Document markup language) INTERNET users MULTIMEDIA systems MULTIMEDIA communications DIGITAL image processing SOFTWARE engineering SOFTWARE productivity GRAPH grammars WORLD Wide Web

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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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2001 IEEE International Conference on Acoustics, Speech, and Signal processing

作者： Wang, D. Mersereau, R.M. Agere Systems StarCore Technology Center Atlanta GA 30328 United States

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 idea based on pixel intensity, we develop a three-level signal representation and an analysis-by-synthesis feedback frame-work. 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 contribute to the analysis, modeling, and transmission of multimedia signals for desktop visual communications.

关键词： image coding

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Efficient implementation of video post-processing algorithms on the BOPS parallel architecture

Efficient implementation of video post-processing algorithms...

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IEEE International Conference on Acoustics, Speech, and Signal processing

作者： Petrescu, D BOPS Inc Chapel Hill NC 27514 USA

ISBN: (纸本)0780370414

Deblocking and deringing are two video post-processing techniques largely used to remove coding artifacts and improve the visual quality when rendering low bit rate coded video. The algorithms used to achieve these tasks are computationally intensive and usually require high speed processors to be able to run in real time. Efficient implementations of signal adaptive filters for video post-processing can be obtained using the specialized features of the parallel BOPS(R) DSP cores. The performance achieved by deblocking and deringing CIF and SDTV size video sequences on the MANTA(TM) prototype chip are illustrated. It is shown that such complex tasks may be executed at low clock rates using the BOPS ManArray(TM) technology.

关键词： Video signal processing

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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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