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IEEE International Conference on image processing

作者： P. Salama N. Shroff E.J. Delp Computer Vision and Image Processing Laboratory Purdue Multimedia Testbed Laboratory School of Electrical Engineering Purdue University West Lafayette IN USA Purdue University System West Lafayette IN US

In ATM networks cell loss causes data to be dropped in the channel. When digital video is transmitted over these networks one must be able to reconstruct the missing data so that the impact of these errors is minimized. In this paper we describe a Bayesian approach to conceal these errors. Assuming that the digital video has been encoded using the MPEG1 or MPEG2 compression scheme, each frame is modeled as a Markov random field. A maximum a posteriori estimate of the missing macroblocks and motion vectors is described based on the model.

关键词： Bayesian methods Streaming media Intelligent networks Laboratories Markov random fields Video sequences Interpolation image reconstruction Motion estimation computer errors

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A system for vehicle classification from range imagery

A system for vehicle classification from range imagery

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Southeastern Symposium on System Theory

作者： Shiquan Peng C.A. Harlow Department of Electrical and Computer Engineering and Remote Sensing and Image Processing Laboratory Louisiana State University Baton Rouge LA USA

ISBN: (纸本)0818673524

In this project we consider automated vehicle location and classification systems. Current systems which utilize loop detectors or video cameras have deficiencies. Video based systems are sensitive to environmental conditions and do not perform well in vehicle classification. The new generation of range or distance sensors that are being developed offer the promise of sensors which are not sensitive to lighting conditions and provide information which should give better vehicle detection and classification percentages than current systems. The focus of this project is to develop an automated vehicle location and classification system based upon imagery obtained from range sensors. image analysis operators and classification methods are developed for vehicle classification. Preliminary results indicate that accurate vehicle classification can be obtained.

关键词： Vehicle detection Radar detection Sensor systems Costs Infrared detectors Laser radar image processing Road transportation Machine vision Surveillance

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A control scheme for a data rate scalable video codec

A control scheme for a data rate scalable video codec

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IEEE International Conference on image processing

作者： Ke Shen E.J. Delp Computer Vision and Iniage Processing Laboratory Purdue Multimedia Testbed Labratory School of Electrical Engineering Purdue University West Lafayette IN USA

We present a control scheme for a rate scalable video codec. We describe a wavelet based video codec with motion compensation used to reduce temporal redundancy. The prediction error frames are encoded using an embedded zerotree wavelet (EZW) approach which allows data rate scalability. Since motion compensation is used in the algorithm, the duality of the decoded video may decay due to the propagation of errors in the temporal domain. An adaptive motion compensation scheme is proposed to address this problem. We show that using our control scheme the quality of the decoded video can be maintained at any data rate.

关键词： Video codecs Decoding Motion compensation Scalability Redundancy Transform coding Video sequences Video compression Signal to noise ratio computer vision

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Measuring the distance and orientation of a planar surface using nonstructured lighting

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SYSTEMS AND computerS IN JAPAN 1996年第8期27卷 83-92页

作者： Tsukiyama, T Member Electrotechnical Laboratory Tsukuba Japan 305 Tosbifumi Tsukiyama:graduated in 1972 from the Biological Engineering Department Osaka University where he also received his Dr. of Eng. degree. He joined Electrotechnical Laboratory Ministry of Tread and Industry (Japan) in 1972. At present he is Senior Researcher at Computer Vision Section Intelligent Systems Division ETL. He was a Visiting Researcher at University of Illinois during 1984–1985. He has been interested in vision system for mobile robots and image processing architectures. He is a member of the Society of Instrumental and Control Engineers Japan Robotics Society of Japan and Information Processing Society of Japan.

This paper proposes a method of 3-dimensional measurement of a planar surface by using two fixed light sources and a TV camera. A set of two images is recorded by the camera switching on each light alternately. The peak of the luminance distribution in each image is detected, and the orientation and distance of the planar surface are calculated. The position of the peak of a luminance distribution can be estimated accurately by using an image processing. The light sources can be conventional apparatus with no particular structure. The method is simple and suitable for a vision system on an indoor mobile robot.

关键词： distance to surface orientation of planar surface point light source luminance distribution ring light

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Texture segmentation using hierarchical wavelet decomposition

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PATTERN RECOGNITION 1995年第12期28卷 1819-1824页

作者： Salari, E Ling, Z Computer Vision and Image Processing Laboratory Department of Electrical Engineering University of Toledo Toledo OH 43606 U.S.A.

This paper presents a texture segmentation algorithm based on a hierarchical wavelet decomposition. Using Daubechies' four-tap filter, an original image is decomposed into three detail images and one approximate image. The decomposition can be recursively applied to the approximate image to generate a lower resolution of the pyramid. The segmentation starts at the lowest resolution using the K-means clustering scheme and textural features obtained from various sub-bands. The result of segmentation is propagated through the pyramid to a higher resolution with continuously improving the segmentation. The lower resolution levels help to build the contour of the segmented texture, while higher levels refine the process, and correct possible errors.

关键词： Texture segmentation Wavelet transform Clustering algorithm Multiresolution segmentation

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Multiresolution sequential edge linking

Multiresolution sequential edge linking

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IEEE International Conference on image processing

作者： G.W. Cook E.J. Delp School of Electrical Engineering Computer Vision and Image Processing Laboratory Purdue University West Lafayette IN USA

We describe a multiresolution approach to edge detection using a sequential search algorithm. The use of a multiresolution image pyramid allows the integration of global edge information contained in lower resolutions to guide the sequential search at higher resolutions. As a consequence, the dependence on a priori knowledge of the image edges is greatly reduced. Estimating the sequential search parameters from lower resolution images provides for a more accurate and less costly search of edge paths in the image.

关键词： Joining processes image edge detection image resolution Spatial resolution Pixel computer vision image processing Signal to noise ratio Technological innovation Laboratories

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A fast algorithm for video parsing using MPEG compressed sequences

A fast algorithm for video parsing using MPEG compressed seq...

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IEEE International Conference on image processing

作者： K. Shen E.J. Delp School of Electrical Engineering Computer Vision and Image Processing Laboratory Purdue University West Lafayette IN USA

Video parsing is a fundamental operation used in many digital video applications such as digital libraries and video servers. The accuracy and execution speed of the parsing algorithm is critical if large amounts of video data are to be processed, particularly in real-time. We present a new algorithm to reconstruct DC coefficient images of a DCT and motion compensation compressed video sequence, e.g. MPEG. The histograms of the DC coefficient images can be used to detect scene changes.

关键词： Video compression Transform coding Software libraries image reconstruction Discrete cosine transforms Motion compensation image coding Video sequences Histograms Layout

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Error concealment techniques for encoded video streams

Error concealment techniques for encoded video streams

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IEEE International Conference on image processing

作者： P. Salama N.B. Shroff E.J. Coyle E.J. Delp School of Electrical Engineering Computer Vision and Image Processing Laboratory Purdue University West Lafayette IN USA

In this paper we describe two error-recovery approaches for MPEG encoded video over ATM networks. The first approach aims at reconstructing each lost pixel by spatial interpolation from the nearest undamaged pixels. The second approach recovers lost macroblocks by minimizing intersample variations within each block and across its boundaries. Moreover, a new technique for packing ATM cells with compressed data is also proposed.

关键词： Streaming media Asynchronous transfer mode Decoding Video compression image coding Video sequences computer errors computer vision image processing Laboratories

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SYSTEMS AND computerS IN JAPAN 1995年第11期26卷 100-109页

作者： WAKIMOTO, K TANAKA, S MAEDA, A SHIMA, M Member Computer and Information Systems Laboratory Mitsubishi Electric Corporation Kamakura Japan 247 Members ALira Maeda:received his M.S. degree in Electrical Engineering from Osaka University and joined Mitsubishi Electric Corporation in 1971. He has been with Information Systems Research Lab. since. He has been working on image information processing systems among others. He is a member of the Information Processing Society. Nonmember

An efficient method to retrieve necessary information from drawings for plant diagrams, logic circuit diagrams, etc. stored in a database is presented. In the image information retrieval systems currently in use, a keyword is assigned to each diagram and information is retrieved by the user by giving the keyword. When the features of the desired image are not registered as a keyword, however, its retrieval becomes difficult. In this paper a method is proposed in which the user shows features of the desired diagram using a sample diagram and a section similar to the sample diagram is retrieved. In this research, diagrams consisting mainly of symbols and connecting lines are considered. This kind of diagram is represented by a graph and similarities in topological features between the sample graph and graph representations of the diagrams in the database are evaluated. The retrieval is then performed based on the value obtained. The results of an experiment conducted using plant diagrams show that similar diagrams can be retrieved using this method.

关键词： image DATABASES MATCHING SIMILARITY RETRIEVAL PLANT DIAGRAMS

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An efficient algorithm for DTMF decoding using the subband NDFT

An efficient algorithm for DTMF decoding using the subband N...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： S. Bagchi S.K. Mitra Department of Electrical and Computer Engineering Signal and Image Processing Laboratory University of California Santa Barbara CA USA

An algorithm based on the subband nonuniform discrete Fourier transform (SB-NDFT) is proposed for decoding dual-tone multi-frequency (DTMF) signals. To decode a DTMF signal, its energy at the eight DTMF frequencies must be determined by evaluating samples of the NDFT at these frequencies. In the proposed SB-NDFT algorithm, these NDFT samples are computed by decomposing the input signal into two subbands. Since DTMF signals occupy the low-frequency part of the telephone bandwidth, the higher subband can be discarded for a fast, approximate computation. A performance comparison between algorithms based on the NDFT, SB-NDFT, DFT, and SB-DFT shows that the SB-NDFT requires the lowest number of computations to attain a specified level of performance.

关键词： Decoding Frequency Discrete Fourier transforms Signal processing image processing Laboratories Telephony Bandwidth Communication system signaling Telephone sets

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