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International conference on Information, Communications and Signal processing

作者： Prashant Bansod U.B. Desai Nitin Burkule SPANN Laboratory Electrical Engineering Department Indian Institute of Technology Bombay India Asian Heart Institute and Research Center Mumbai India

ISBN: (纸本)9781424409822

We present a guided local search (GLS) algorithm in a multi-frame environment for the detection of endocardial contours in echo cardiographic image sequences. the proposed method requires minimal user intervention at the first frame of the image sequence for specifying the candidate points of the contour. the initial contour is approximated by fitting an ellipse in the region defined by the points specified. First level of regularization on the contour is made by radial gradient search incorporating both magnitude and direction. the second level of regularization makes use of the GLS algorithm. the GLS with features and constraints for solution space and penalty terms overcome the optimization being trapped in local minima. the proposed method also incorporates the temporal information from the adjacent frames during the regularization process. the subsequent frames in sequence are initialized by the final contour of the previous frame. the algorithm developed was applied to 20 data sets over a cardiac cycle and the results were validated by comparing computer generated boundaries to those manually outlined by one expert. the maximum error in the contours detected was plusmn3.1 mm. the application of guided local search algorithm proposed in this paper offers a fast and efficient method for semiautomatic segmentation of heart chambers in 2D echocardiography sequences.

关键词： Echocardiography image segmentation Heart image sequences Cardiology Cardiography Constraint optimization computer errors Application software Biomedical imaging

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Biased estimation of Rician K factor

Biased estimation of Rician K factor

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International conference on Information, Communications and Signal processing

作者： Nitesh Shroff K. Giridhar Telecommunications and Computer Networking (TeNeT) Group Department of Electrical Engineering Indian Institute of Technology Madras Chennai India

ISBN: (纸本)9781424409822;1424409829

the time varying envelope of the received signal, for the case when a line of sight (LoS) component exists between the transmitter and the receiver, is described by a Rician distribution with Rician factor K. the Rician factor is a measure of the severity of the fading, with K = 0 being the most severe Rayleigh fading, and K = oo representing essentially a non-fading channel. K factor estimation is often thus required for link budget calculation as well as to determine the best possible space - time precoder when multiple transmit antennas are used. Here, we discuss the maximum likelihood estimator (MLE) and a moment based estimator for the estimation of the K factor. the James-Stein estimator (JSE), which is a biased, non - linear estimator, is then used to estimate the K factor and its performance is compared with the MLE. It is shown that using biased estimators (such as the JSE) for K factor estimation, can significantly improve the estimation performance. At low and high K factors, the JSE is similar to MLE, whereas for medium values of K, the JSE can outperform MLE significantly.

关键词： Rician channels Maximum likelihood estimation MIMO Transmitters Rayleigh channels computer networks Telecommunication computing Probability density function Estimation error image restoration

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Unsupervised classification of events: A semantic rule based on color moments of background and foreground method

Unsupervised classification of events: A semantic rule based...

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International conference on Information, Communications and Signal processing

作者： P. Shivakumara G. S. V. S Sivaram Basavaraj S. Anami Department of Computer Science School of Computing National University of Singapore Singapore Department of Computer Science Indian Institute of Science Bangalore Karnataka India Department of Computer Science Basaveshwar Engineering College Bangalore Karnataka India

ISBN: (纸本)9781424409822

Identification/labeling of the events is still an open problem for researchers due to the problem of semantic gap between the low level features and human perception though it is essential in solving the fundamental problem of automatic albuming, managing digital photography and performance of their retrieval system. Hence, in this paper, we present novel unsupervised semantic rule (USR) based method to label the events such as indoor (wedding) and outdoor (picnic) by establishing semantic relationship between successive background and foreground information of digital photographs. In order to derive a semantic rule, we have used color moments as features and Euclidean distance measure as the nearest neighbor. the rule is defined as the mean values of background information of images, which is lesser than mean value of foreground information in case of indoor event. Similarly, the mean value of background information is higher than the mean values of foreground information in case of outdoor images, this is true because of the fact that background information of Indoor photographs is constant over a long time in a whole event, whereas foreground information varies during the same time. Similarly, the background information varies in case of outdoor photographs but foreground information is almost constant. Experimental results of the proposed method are compared with results of the existing methods to bring the superiority of the proposed method in terms of robustness, simplicity, and accuracy in labeling the events without a priori knowledge.

关键词： Labeling computer science Feature extraction image databases Spatial databases Digital photography Nearest neighbor searches Clustering algorithms Educational institutions Humans

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Software tool for Breast Cancer Brachytherapy Planning using VTK

Software tool for Breast Cancer Brachytherapy Planning using...

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IEEE International conference on Cognitive Informatics

作者： Y Jiang L Cao R Sankreacha J Pignol Department of Computer Science Ryerson University Toronto Ontario Canada SunnyBrook Regional Cancer Center Toronto Canada

this paper describes a software system tailored to planning, viewing and modifying treatment plans for breast cancer brachytherapy treatments. the software is developed based on a new technique of adjuvant partial breast irradiation using 103 Pd permanent seed implant developed at Toronto-Sunnybrook Regional Cancer Center. the software uses Visual Tool Kit (VTK) open source and Visual C++. We use VTK to render the 3D CT images and regions of interest, and reconstruct the images from supine position CT scan to oblique direction for breast implantation purpose. the seed planning is done on the reconstructed images and can be viewed in 3D space from any oblique angle. While prostate seed implant is a well established procedure supported by commercial software systems, breast implant is in its infancy and there is no commercial software available to support this treatment. the software we have developed called "vision" aims at becoming a standard tool for breast cancer brachytherapy treatment. vision provides the following functionalities: processing DICOM CT images and DICOM ROI structure sets, generating oblique images to allow radiation seeding plantation to be carried out in the direction that is suitable for breast brachytherapy. It includes a source editor for managing 103 Pd source model data, and planning and viewing the seeding plan with the CT 3D data set. this editor provides intuitive and accurate visual aid to help oncologists to analyze their treatment plans, and also offers 3D simulator of the seeding procedure. A "fiducial needle" that is used to hook the surgical cavity and that is eventually attached to a template guiding the insertion of needles loaded with the seeds is also been simulated in the vision software. vision software has been tested with patients' data and the results are shown in this paper.

关键词： Software tools Breast cancer Brachytherapy Computed tomography Implants Software systems Open source software image reconstruction DICOM Needles

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Workflow for development and testing of an embedded vision application

Workflow for development and testing of an embedded vision a...

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6th IASTED International conference on Visualization, Imaging, and image processing, VIIP 2006

作者： Hemetsberger, H. Kogler, J. Humenberger, M. Zinner, C. Kubinger, W. Borbély, S. Dependable Embedded Control Systems Group ARC Seibersdorf Research GmbH Donau-City- Str. 1 1220 Vienna Austria

ISBN: (纸本)0889865981

Developing computer vision applications is a challenging task. Realizing such an application as an embedded system is even more difficult, due to the limited resources of the target platform. In this paper the methods for the realization of such an embedded vision application are introduced. this includes a description of a workflow that supports the development of an embedded vision system. Also, the tools used for development and testing of this application are presented. For each step in the development process either off-the-shelf or self-developed tools were deployed. the embedded system, a stereo vision sensor, was part of an autonomous vehicle which participated in the DARPA Grand Challenge 2005. this system was used for obstacle and lane detection in this competition.

关键词： computer vision

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Vector-based medical image segmentation using adaptive Delaunay triangulation

Vector-based medical image segmentation using adaptive Delau...

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6th IASTED International conference on Visualization, Imaging, and image processing, VIIP 2006

作者： Španel, Michal Kršek, Premysl Department of Computer Graphics and Multimedia Faculty of Information Technology Brno University of Technology Czech Republic

ISBN: (纸本)0889865981

the image segmentation plays an important role in medical image processing. Many segmentation algorithms exist. Most of them produce raster data which is not suitable for further 3D geometrical modeling of tissues. In this paper, a vector segmentation algorithm based on an adaptive Delaunay triangulation is proposed. Triangular meshes are used to divide an image into several non-overlapping regions whose characteristics are similar. Novel methods for improving quality of the mesh and its adaptation to the image structure are also presented.

关键词： image segmentation

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Detecting false captioning using common-sense reasoning

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DIGITAL INVESTIGATION 2006年第SUPPL.期3卷 S65-S70页

作者： Lee, Sangwon Shamma, David A. Gooch, Bruce Northwestern Univ Dept Elect Engn & Comp Sci Technol Inst L359 Evanston IL 60208 USA

Detecting manipulated images has become an important problem in many domains (including medical imaging, forensics, journalism and scientific publication) largely due to the recent success of image synthesis techniques and the accessibility of image editing software. Many previous signal-processing techniques are concerned about finding forgery through simple transformation (e.g. resizing, rotating, or scaling), yet little attention is given to examining the semantic content of an image, which is the main issue in recent image forgeries. Here, we present a complete workflow for finding the anomalies within images by combining the methods known in computer graphics and artificial intelligence. We first find perceptually meaningful regions using an image segmentation technique and classify these regions based on image statistics. We then use AI common-sense reasoning techniques to find ambiguities and anomalies within an image as well as perform reasoning across a corpus of images to identify a semantically based candidate list of potential fraudulent images. Our method introduces a novel framework for forensic reasoning, which allows detection of image tampering, even with nearly flawless mathematical techniques. (c) 2006 DFRWS. Published by Elsevier Ltd. All rights reserved.

关键词： image forgery detection false captioning digital photomontage image segmentation common-sense reasoning

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image translation and rotation on hexagonal structure

Image translation and rotation on hexagonal structure

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6th IEEE International conference on computer and Information Technology, CIT 2006

作者： He, Xiangjian Jia, Wenjing Hur, Namho Wu, Qiang Kim, Jinwoong Computer Vision Research Group University of Technology Sydney Digital Broadcasting Research Division Electronics Telecommunications Research Institute 161 Gajeong-dong Yuseong-gu Daejeon 305-700 Korea Republic of

ISBN: (纸本)076952687X

image translation and rotation are becoming essential operations in many application areas such as image processing, computer graphics and pattern recognition. Conventional translation moves image from pixels to pixels and conventional rotation usually comprises of computation-intensive CORDIC operations. Traditionally, images are represented on a square pixel structure. In this paper, we perform reversible and fast image translation and rotation based on a hexagonal structure. An image represented on the hexagonal structure is a collection of hexagonal pixels of equal size. the hexagonal structure provides a more flexible and efficient way to perform image translation and rotation without losing image information. As there is not yet any available hardware for capturing image and for displaying image on a hexagonal structure, we apply a newly developed virtual hexagonal structure. the virtual hexagonal structure retains image resolution during the process of image transformations, and almost does not introduce distortion. Furthermore, images can be smoothly and easily transferred between the traditional square structure and the hexagonal structure. © 2006 IEEE.

关键词： image analysis

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Comparison of voronoi based scattered data interpolation schemes

Comparison of voronoi based scattered data interpolation sch...

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6th IASTED International conference on Visualization, Imaging, and image processing, VIIP 2006

作者： Bobach, Tom Hering-Bertram, Martin Umlauf, Georg Geometric Algorithms Group / IRTG University of Kaiserslautern Germany Computer Graphics Group University of Kaiserslautern Germany Geometric Algorithms Group University of Kaiserslautern Germany

ISBN: (纸本)0889865981

Voronoi based interpolation employs the concept of natural neighbors to define an interpolating function over discrete data known at scattered sample points. In this work we review the two main concepts for improving interpolation continuity inside the convex hull of the sample domain and compare four natural neighbor interpolants of C1 and C2 continuity. We give a visual presentation of all interpolants to provide insight into their overall behavior in addition to a comparison of their analytical and practical properties.

关键词： Interpolation

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Behaviour-based multi-robot formations using computer vision

Behaviour-based multi-robot formations using computer vision

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6th IASTED International conference on Visualization, Imaging, and image processing, VIIP 2006

作者： Payá, L. Gil, A. Reinoso, O. Ballesta, M. Ñeco, R. Spain

ISBN: (纸本)0889865981

Multi-robot systems is a very attractive field of research in robotics, due to the fact that a team of robots is able to accomplish certain tasks that a single robot cannot carry out on his own. this paper presents a behaviour-based method for multi-robot formations using computer vision. A team of robots must move around the environment, keeping a relative position between them and avoiding the collision with possible obstacles. computer vision has been used for the localization of the robots using the images captured by the camera they carry on their top. Different methods have been tested to obtain the leader robot pose, developing finally a very stable method to calculate distance and orientation. the final control has been built as a composition of several basic behaviours that calculate an action model using the information of the environment. these actions are composed using fuzzy logic to obtain a high-level behaviour. the algorithms developed have been tested over a team of WiFiBot mobile robots, with good results.

关键词： Multipurpose robots

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