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2nd Indian International Conference on Artificial Intelligence, IICAI 2005

作者： Nanda, P.K. Patra, D. Pradhan, A. Department of Electrical Engineering Image Processing and Computer Vision Laboratory National Institute of Technology Rourkela Orissa 769008 India

ISBN: (纸本)0972741216

In this paper, we propose a hybrid Tabu Expectation Maximization (TEM) Algorithm for segmentation of Brain Magnetic Resonance (MR) images in both supervised and unsupervised framewrok. Gaussian Hidden Markov Random Field (GHMRF) is used to model the available degraded image. In supervised framework, the apriori image MRF model parameters as well as the GHMRF model parameters are assumed to be known. The class labels are estimated using the Maximum a Posteriori (MAP) estimation criterion. In unsupervised framework, the problem of model parameter estimation and label estimation is formulated in Expectation Maximization (EM) framework. The labels are estimated using the proposed Tabu Search algorithm while the model parameters are the maximum likelihood estimates. Our proposed algorithm yields results with arbitrary initial paramater set and thus overcomes the problem of proper choice of initial parameters. The results obtained are comparable with the results obtained by using the algorithm proposed by Zhang ***. [15] , where the Iterated Conditional Mode (ICJM) algorithm is used for computing the MAP estimates. Copyright © IICAI 2005.

关键词： Tabu search

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A Local image Interpolation Method Based On Gradient Analysis

A Local Image Interpolation Method Based On Gradient Analysi...

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2005 International Conference on Neural Networks and Brain(ICNN&B’05)

作者： Tian Yan Liu Bin Li Tao Department of electronic and information engineering Huazhong University of Science & Technology School of computer science and technology Huazhong University of Science & Technology Key Laboratory of Education Ministry for Image Processing and Intelligent Control Huazhong University of Science & Technology

ISBN: (纸本)0780394224

image interpolation has been widely used and studied in the fields of image *** the different complexities along the different directions,a novel image interpolation method based on gradient analysis is presented in this ***,for each point that need to be interpolated,it's the gradient values along the horizontal and vertical directions are estimated ***,different interpolation methods are carried out along these two directions according to the gradient values,that is a higher order interpolation method is applied if the gradient value is greater than certain threshold;otherwise,a lower order interpolation method is *** method gives an attention to the precision and complexity of interpolation procedure. Experimental results show that the proposed method is feasible and promising.

关键词： Gradient image interpolation root mean square error

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Variational-based method to extract parametric shapes from images

Variational-based method to extract parametric shapes from i...

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International Conference on computer vision (ICCV)

作者： M.T. El-Melegy N.H. Al-Ashwal A.A. Farag Electrical Engineering Department Assiut University Asyut Egypt Computer Vision and Image Processing Laboratory University of Louisville KY USA

In this paper, we propose a variational method to segment image objects, which have a given parametric shape based on a level-set formulation of the Mumford-Shah functional, and the shape parameters. We define an energy functional composed by two complementary terms. The first one detects object boundaries using a Chan-Vese-like method. The second term constrains the contour to find a shape compatible with the parametric shape. The segmentation of the object of interest is given by the minimum of our energy functional. This minimum is computed with the calculus of variation and the gradient descent method that provide a system of evolution equations solved with the well-known level set method. We focus in this paper on the parametric category of image linear objects. Applications of the proposed model are presented on synthetic and real images

关键词： Shape image segmentation Level set computer vision Focusing image processing Object detection Calculus Application software Equations

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An interaction interface for multiple agents on shared 3D display

An interaction interface for multiple agents on shared 3D di...

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2nd International Conference on Cooperative Design, Visualization, and engineering, CDVE 2005

作者： Choi, Jeong-Dan Hwang, Chi-Jeong Telematics Solution Research Team Telematics and RFID Research Department Electronic and Telecommunications Research Institute 161 Gajeong-dong Yuseong-gu Dajeon 305-350 Korea Republic of Image Processing Laboratory Computer Engineering Department Chungnam National University 220 Gung-dong Yuseong-gu Daejeon 305-764 Korea Republic of

ISBN: (纸本)3540289488

In the multi-user VR game, wide stereoscopic display is an important component that supports immersion and perception to the gamer. Because the space in front of the display allows multi-participants to collaborate and guarantees view with the entire field of view for each user. This paper describes a method to integrate user interfaces for interactions among users wear VR devices on wide stereoscopic display. The key technologies of our proposed system include the problems of coordination with various devices to treat user events in real-time, synchronization of PC clusters which renders the VR contents, and seamless display of multi-channel display surfaces. To accomplish this, we propose a VR game display platform composed of multi-projectors, stereoscopic see-through head mounted device, and gesture recognition system for collaborative interactions. Our preliminary results showed that the proposed strategy well suits high resolution application at real-time frame rate for VR game. © Springer-Verlag Berlin Heidelberg 2005.

关键词： Display devices

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Enhancement of stents using interference of low-frequency ultrasonic echo signals

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Journal of Medical Ultrasonics 2004年第2期31卷 67-73页

作者： Ohashi, Gosuke Ohya, Akihisa Tobise, Kazimobu Akiyama, Iwaki Faculty of Engineering Shizuoka University Hamamatsu Japan Institute of Information Sciences and Electronics University of Tsukuba Tsukuba Japan Shoryo Electronic Corporation Kamakura Japan Faculty of Engineering Shonan Institute of Technology Fujisawa Japan Image Processing and Vision Research Laboratory Department of Electrical and Computer Engineering University of California at Santa Barbara Santa Barbara CA 93106-9560 United States

Purpose. We set out to enhance the imaging of stents used for coronary coarctation surgery without imaging the reticulation of the stent. Because the stent is a reticulated structure, there is a relation between ultrasound wavelength and the interstice reticulation that produces the echo. Methods. First we performed computer simulation by ultrasound frequency of transmitted signals to analyze this relation. Then, instead of controlling the transmitted wave, we processed the returned signals through a band-pass filter because of the difficulty of controlling the transmitted waves of diagnostic ultrasound equipment. Following this, we conducted experiments on an agar gel phantom containing a stent to verify the effectiveness of this method. Results. The simulation confirmed that the stent was apparent when the ultrasonic wavelength equaled the product of an integer and twice the interval of the reticulation of the stent. Application of a band-pass filter of 0.8 to 1.5MHz to the waveform returned from the agar gel phantom containing the stent. Conclusions. The effectiveness of this method in depicting the stent was confirmed. © The Japan Society of Ultrasonics in Medicine 2004.

关键词： Interference Received waveform Signal processing Stent Ultrasonic echography

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Real-time vision-based approach for probe tracking in operating room

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International Congress Series 2004年 1268卷 467-472页

作者： Aly A. Farag M.Sabry Hassouna Ayman El-Baz S. Hushek Computer Vision and Image Processing Laboratory Electrical and Computer Engineering University of Louisville 403 Lutz Hall Bldg. Louisville KY 40292 USA Department of Neurological Surgery University of Louisville USA

A hand-held surgical probe is an essential component of any image-guided neurosurgery (IGNS). During the surgical procedure, the IGNS tracks the probe position and displays the anatomy beneath it as three orthogonal image slices on a workstation-based 3D imaging system. Existing IGNS systems use different tracking techniques including mechanical, optical, ultrasonic, and electromagnetic systems. In this paper, we present a new computational vision-based probe tracking technique, which provides both position and orientation. We also propose another new computational vision-based technique to track the patient head and thus compensate for its movement during probing procedure. The proposed system is completely passive, its stereo cameras detect the presence of the probe using available visible light, and reports on their exact location and orientation in patient physical space in real time. We have validated the system using a skull phantom and a hand made probe.

关键词： image-guided neurosurgery Head motion tracking Probe tracking vision tracking

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Collaborative interactions on 3D display for multi-user game environments

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6th Asia Pacific Conference on computer Human Interaction, APCHI 2004

作者： Choi, Jeong-Dan Jang, Byung-Tae Hwang, Chi-Jeong Telematics Solution Research Team Telematics Research Department Electronic and Telecommunications Research Institute 161 Gajeong-dong Yuseong-gu Dajeon305-350 Korea Republic of Image Processing Laboratory Computer Engineering Department Chungnam National University 220 Gung-dong Yuseong-gu Daejeon305-764 Korea Republic of

ISBN: (纸本)3540223126

This paper describes a method to integrate VR interfaces on 3D display for multiuser game environments, which addresses the problem of synchronization and calibration multiple devices together to treat game events. The challenge we interest in is how to build and use a low cost 3D display that collaborative interact for multi-user immersive game requirements. In the multi-user VR game, 3D display is an important component that supports immersion to gamer. So our display system is supported by following two methods. Projection-based screen system makes it possible to display on large-sized surface. Stereo sea-through HMD is to produce private area as well as public area: a viewer-oriented and private information display. To accomplish this system, we concrete a multi-projector system for creating a seamless wide-area view, head mounted device to play game, and gesture recognition system for collaborative interactions. Our preliminary system is well suited for jungle hunting as game contents with surround displays running on a PC clusters. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Three dimensional displays

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An improved edge-model based representation and its application in image post-processing

An improved edge-model based representation and its applicat...

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

作者： Chi-keung Fong Wai-kuen Cham Computer Vision and Image Processing Electronic Engineering Department Chinese University of Hong Kong New Territories Hong Kong China

ISBN: (纸本)0780376633

images can be represented using as locations and parameters of edges based on an edge mode. The representation was shown to be effective to reduce coding errors of images coded using SPIHT in an image postprocessing method. However, the representation results several artifacts which include "smudge and halos" artifacts and stripping artifacts. We have found the causes of these artifacts and propose a revised representation that has these artifacts significantly suppressed Also, we shall demonstrate that the revised representation can further improve the performance of the image post-processing algorithm.

关键词： image processing Parameter estimation image reconstruction Application software computer vision image coding image storage image converters image edge detection Laboratories

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Video reconstructions in dentistry

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Orthodontics and Craniofacial Research 2003年第SUPPL1期6卷 108-116页

作者： Farag, A.A. Eid, A. Electrical and computer Engineering Department University of Louisville Computer Vision and Image Processing Laboratory Louisville KY 40292 United States

Objectives: To present two practical techniques for threedimensional (3D) modeling of the human jaw from a sequence of intra-oral images. Design: A data acquisition system consists of: 3D digitizing arm, CCD camera and a laser projector in addition to a software module of two 3D modeling techniques;shape from shading (SFS) and space carving (SC). Setting and sample population - Several experiments have been conducted on a sample of students at the computer vision and image processing (CVIP) laboratory at the University of Louisville, Louisville, KY. Other experiments were performed on solid models of human jaw. Experimental variable: The SFS technique, using perspective projection and camera calibration, extracts the 3D information from a sequence of two-dimensional images of the jaw. Data fusion of range data and 3D registration techniques develop the complete jaw model. The SC approach is implemented on a sequence of calibrated images. On the two reconstructions, we fit a mesh model to the data, in order to create a solid 3D model. Outcome measure: The accuracy of the reconstructed 3D model of human jaw is calculated based on the measurements on real jaws. Results: The SFS-based technique seems to provide more faithful information about the shape of the tooth tops. However, the SC algorithm successfully reconstructed 3D models of the human jaw with sub-millimeter accuracy, which is as accurate as (or even better than) the first technique without using any range measurements or laser projectors. The average error in distance calculation was found to be 0.74 mm, which is an acceptable resolution for many orthodontics and maxillofacial applications. Conclusion: Accurate 3D reconstruction of the human jaw enables many orthodontics and dental imaging researchfindings to be applied directly to a digital jaw model - not to a cast - using computer vision and medical imaging tools. © 2003 Blackwell Munksgaard.

关键词： Data fusion Jaw modeling Registration Shape from shading Space carving

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An overview of self-calibration in sensor array processing

An overview of self-calibration in sensor array processing

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International Symposium on Antennas, Propagation and EM Theory (ISAPE)

作者： Li Qiong Gan Long Ye Zhongfu Image Information Processing Laboratory Department of Computer and Information Hefei University of Technology Hefei China Institute of Statistical Signal Processing Department of Electronic Engineering and Information Science University of Science and Technology Hefei China

The performance of high-resolution DOA estimation methods seriously degenerates when there are model errors in array manifold. According to various prior knowledge of array manifold, this paper classifies series of array self-calibration methods based on second order statistics, then discusses them and concludes their advantages and disadvantages, finally gives some prospect for research on self-calibration.

关键词： Sensor arrays Array signal processing Calibration Parameter estimation Statistics Covariance matrix Direction of arrival estimation Mutual coupling Random processes Signal processing

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