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IEEE International conference on image processing

作者： M.R. Hashemi L. Winger S. Panchanathan School of Information Technology and Engineering University of Ottawa Ottawa ONT Canada Visual Computing and Communications Laboratory Department of Computer Science and Engineering Arizona State University Saudi Arabia

Digital video databases in compressed form are becoming widely available. In applications such as video browsing, and picture in picture, for a lower bitrate, there is a need to down-sample the video before transmission. The conventional approach to downscale a compressed video sequence is to decompress it at the video server, perform the down-sampling in the pixel domain and then recompress it for efficient delivery. This process is computationally intensive due to the motion estimation process required during the recompression phase. In the alternative compressed domain approach, the motion vectors of the downscaled video sequence are computed directly from the motion vectors of the original full size stream. In this paper we propose a compressed domain technique that generates a better estimate for the downscaled motion vectors. Simulations suggest that the performance achieved with the proposed method is superior by up to 1 dB to the current compressed domain techniques.

关键词： Transform coding Video compression Video sequences Motion estimation Discrete cosine transforms image coding Bit rate image storage Information technology Databases

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Multi-chip neuromorphic motion processing

Multi-chip neuromorphic motion processing

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conference on Advanced Research in VLSI

作者： C.M. Higgins C. Koch Division of Biology 139-74 California Institute of Technology Pasadena CA USA

We describe a multi-chip CMOS VLSI visual motion processing system which combines analog circuitry with an asynchronous digital interchip communications protocol to allow more complex motion processing than is possible with all the circuitry in the focal plane. The two basic VLSI building blocks are a sender chip which incorporates a 2D imager array and transmits the position of moving spatial edges, and a receiver chip which computes a 2D optical flow vector field from the edge information. The elementary two-chip motion processing system consisting of a single sender and receiver is first characterized. Subsequently, two three-chip motion processing systems are described. The first such system uses two sender chips to compute the presence of motion only at a particular stereoscopic disparity. The second such system uses two receivers to simultaneously compute a linear and polar topographic mapping of the image plane, resulting in information about image translation, rotation, and expansion. These three-chip systems demonstrate the modularity and flexibility of the multi-chip neuromorphic approach.

关键词： Neuromorphics Optical receivers Very large scale integration Optical arrays Optical computing CMOS digital integrated circuits CMOS analog integrated circuits CMOS process Protocols image motion analysis

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Analysis and synthesis of 3-D face image sequence based on model-based image coding scheme with an Internet browser

Analysis and synthesis of 3-D face image sequence based on m...

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IEEE International conference on image processing

作者： Min Chul Park N.P. Chandrasiri T. Naemura M. Kaneko H. Harashima Department of Informatics and Communication Engineering University of Tokyo Bunkyo Tokyo Japan Course in Elcctronic Eng University of Electro-Communications Japan

In this paper, an efficient analysis method for global head motion, and a synthesis method of 3-D face scenes using model-based image coding techniques on the Internet browser are presented. By applying the techniques of model-based image coding in facial image sequence, human face or anthropomorphic agents can be synthesized with real facial motion on the internet browser using VRML and/or JAVA. While typical model-based image coding produces synthetic face scenes in 2-D space at the receiver terminals, the proposed scheme can produce synthetic face scenes in 3-D space interactively supporting some visual standard. This enables users to synthesize 3-D face scenes at any terminals. In this sense, it improves the portability of synthesis in model-based image coding. To speed up the computation in the analysis process, a new method that generates referential frame dynamically is proposed. To produce a 3-D face model which is suitable for the purpose of application, an idea of automatic face modeling using different 3-D face models is presented. Experimental results show the usefulness of applying the techniques of model-based image coding to the analysis of facial motion and synthesis of 3-D face scene on the internet browser.

关键词： image analysis image sequence analysis image sequences Layout image coding Internet image motion analysis Motion analysis Head Humans

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visual communications and image processing'98

Visual communications and image processing'98

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visual communications and image processing '98

The proceedings contains 52 papers from the conference on visual communications and image processing 98. The topics discussed include: edge-assisted upper-bands coding techniques;robust embedded zerotree wavelet coding algorithm;motion estimation and compensation based on region-constrained warping prediction;new algorithm for motion estimation on interlaced video;performace evaluation of the MPEG-4 visual coding standard and standard-based software-only video conferencing codec on ultra SPARC.

关键词： image coding

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Subpixel motion estimation for super-resolution image sequence enhancement

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JOURNAL OF visual COMMUNICATION AND image REPRESENTATION 1998年第1期9卷 38-50页

作者： Schultz, RR Meng, L Stevenson, RL Univ N Dakota Dept Elect Engn Grand Forks ND 58202 USA LSI Log Corp Digital Video Prod Milpitas CA 95035 USA Univ Notre Dame Dept Elect Engn Lab Image & Signal Anal Notre Dame IN 46556 USA

Super-resolution enhancement algorithms are used to estimate a high-resolution video still (HRVS) from several low-resolution frames, provided that objects within the digital image sequence move with subpixel increments, A Bayesian multiframe enhancement algorithm is presented to compute an HRVS using the spatial information present within each frame as well as the temporal information present due to object motion between frames, However, the required subpixel-resolution motion vectors must be estimated from low-resolution and noisy video frames, resulting in an inaccurate motion held which can adversely impact the quality of the enhanced image. Several subpixel motion estimation techniques are incorporated into the Bayesian multiframe enhancement algorithm to determine their efficacy in the presence of global data transformations between frames (i.e., camera pan, rotation, tilt, and zoom) and independent object motion. visual and quantitative comparisons of the resulting high-resolution video stills computed from two video frames and the corresponding estimated motion fields show that the eight-parameter projective motion model is appropriate for global scene changes, while block matching and Horn-Schunck optical flow estimation each have their own advantages and disadvantages when used to estimate independent object motion. (C) 1998 Academic Press.

关键词： image analysis

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Generation of arbitrarily focused images by using multiple differently focused images

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JOURNAL OF ELECTRONIC IMAGING 1998年第1期7卷 138-144页

作者： Kodama, K Aizawa, K Hatori, M Univ Tokyo Dept Elect Engn Tokyo 113 Japan

We propose a novel method of arbitrarily focused image generation using multiple differently focused images. First, we describe our previously proposed select and merge method for all focused image acquisition. We can get good results by using this method but it is not easy to extend this method for generating arbitrarily focused images. Then, based on the assumption that depth of a scene changes stepwise, we derive a formula for reconstruction between the desired arbitrarily focused image and multiple acquired images;we can reconstruct the arbitrarily focused image by iterative use of the formula. We also introduce coarse-to-fine estimation of point spread functions (PSFs) of the acquired images. We reconstruct arbitrarily focused images for a natural scene. In other words, we simulate virtual cameras and generate images focused on arbitrary depths. (C) 1998 SPIE and IS&T. [S1017-9909(98)02201-6].

关键词： Cameras image acquisition Point spread functions

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

Estimation of feature parameters in model-based image coding...

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Meeting on visual communications and image processing

作者： Yu, L Liu, YH Yao, QD Zhejiang Univ Inst Informat & Commun Engn Hangzhou 310027 Peoples R China

ISBN: (纸本)0819431249

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 defined 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： model-based image coding very low bit-rate image coding video conference MPEG-4

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Proceedings of SPIE: visual communication and image processing '98

Proceedings of SPIE: Visual communication and image processi...

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visual communications and image processing '98

The proceedings contains 53 papers from the conference on SPIE: visual Communication and image processing'98. The topics discussed include: image segmentation;motion estimation;video coding;videophones;layered coding systems;low bit-rate encoding;motion compensation;halftone images;multistandard compression;linear-phase filter banks;motion discontinuity patterns;image compression;image quality;video databases;multiresolution analysis;loseless image compressors;vector quantization and multipass color printers.

关键词： image segmentation

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A sequential projections based postprocessor for block-based image coding 9

A sequential projections based postprocessor for block-based...

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9th European Signal processing conference, EUSIPCO 1998

作者： Chang, Joon-Ho Lee, Sang Hwa Kim, Jeong-Kwon Lee, Choong Woong Visual Information Lab. Multimedia R and D Center Samsung Electronics Co. Paldal-gu Suwon442-742 Korea Republic of Image Communications Lab. Institute of New Media and Communications School of Electrical Engineering Seoul National University Seoul152-742 Korea Republic of

In this paper, we propose a novel post-processing techinque to reduce blocking artifacts for block-based image coding schemes. Our approach focuses mainly on the reconstruction of the surface continuity, including the continuity of edges and textures in the image objects. To do this, we introduce a set of continuous functions suitable for characterizing edges and, by a linear combination of these functions, estimate the original artifact-free image. We propose the Projections onto the OverComplete Basis (POCB) algorithm to find linear coefficients satisfying a constraint which controls the difference between the blocky and estimated images. The proposed and conventional techniques are tested on various images compressed by the JPEG standard and vector quantization. The simulation results show that the proposed technique yields better results both objectively and subjectively.

关键词： image coding

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Video object plane segmentation using a morphological motion filter and Hausdorff object tracking

Video object plane segmentation using a morphological motion...

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IEEE International conference on image processing

作者： T. Meier K.N. Ngan Visual Communications Research Group Department of Electrical and Electronic Engineering University of Western Australia Nedlands WA Australia

This paper considers the decomposition of video sequences into so-called video object planes, which is required for the content-based representation of visual objects in MPEG-4. A new segmentation algorithm is described that identifies physical objects using a morphological motion filter. For the object of interest, a two-dimensional binary model is derived based on areas in the scene that are moving differently from the background. This model is updated each frame to pick up possible rotation and changes in shape of the object. Temporal correspondence is established by a Hausdorff object tracker: The binary model sequences guide the actual video object plane extraction. Since the model points correspond to edges detected by the Canny operator; a high object boundary location is achieved. Experimental results demonstrate that our proposed technique can successfully extract the physical object from video sequences.

关键词： Tracking MPEG 4 Standard image motion analysis Optical noise Video sequences Partitioning algorithms Optical filters Layout image segmentation Change detection algorithms

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