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

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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Activation detection in multi-subject studies of fMRI using GLRT

Activation detection in multi-subject studies of fMRI using ...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： S.M. Shams G.A. Hossein-Zadeh H. Soltanian-Zadeh Control and Intelligent Processing Center of Excellence Electrical and Computer Engineering Department Institute for Studies in Theoretical Physics and Mathematics University of Tehran School of Cognitive Sciences Tehran Iran Control and Intelligent Processing Center of Excellence Electrical and Computer Engineering Department Institute for Studies in Theoretical Physics and Mathematics and Medical Image Analysis Laboratory Henry Ford Health System University of Tehran School of Cognitive Sciences Iran

A new method based on generalized likelihood ratio test (GLRT) for activation detection in multi-subject studies of functional MRI (fMRI) is proposed. In this method, we test the correlation between the fMRI time series of different subjects and the bases of a signal subspace which increases the flexibility of method in detecting different shapes of hemodynamic response. The proposed multivariate method can be applied to group studies where the conventional cross-correlation method cannot be used due to its univariate property. This method is applied to both experimental and simulated fMRI data and the results are compared to those of general linear model (GLM). We show that the proposed method detects more significant activated regions in analyzing experimental data and more true voxels in simulated data

关键词： Testing Hemodynamics Brain modeling Process control Intelligent control Physics computing mathematics Time series analysis Magnetic resonance imaging Data analysis

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Hand gesture recognition in camera-projector system

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8th European Conference on computer Vision, ECCV 2004 and International Workshop on Human-computer Interaction, HCI 2004

作者： Licsár, Attila Szirányi, Tamás University of Veszprém Department of Image Processing and Neurocomputing Egyetem u. 10 VeszprémH-8200 Hungary Analogical and Neural Computing Laboratory Computer and Automation Research Institute Hungarian Academy of Sciences Kendeu. 13-17 BudapestH-1111 Hungary

ISBN: (纸本)3540220127

Our paper proposes a vision-based hand gesture recognition system. It is implemented in a camera-projector system to achieve an augmented reality tool. In this configuration the main problem is that the hand surface reflects the projected background, thus we apply a robust hand segmentation method. Hand localizing is based on a background subtraction method, which adapts to the changes of the projected background. Hand poses are described by a method based on modified Fourier descriptors, which involves distance metric for the nearest neighbor classification. The proposed classification method is compared to other feature extraction methods. We also conducted tests on several users. Finally, the recognition efficiency is improved by the recognition probabilities of the consecutive detected gestures by maximum likelihood approach. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Augmented reality

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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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Controlling the false positive detection rate in fuzzy clustering of fMRI data

Controlling the false positive detection rate in fuzzy clust...

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IEEE International Symposium on Biomedical Imaging

作者： H. Jahanian H. Soltanian-Zadeh G.A. Hossein-Zadeh Signal and Image Processing Group School of Intelligent Systems Institute of Studies in Theoretical Physics and Mathematics Tehran Iran Elec. Eng. Department Control and Intelligent Processing Center of Excellence University of Tehran Tehran Iran Image Analysis Laboratory Radiology Department Henry Ford Health System Detroit MI USA

Despite its potential advantages for fMRI analysis, fuzzy C-means (FCM) clustering suffers from limitations such as the need for a priori knowledge of the number of clusters, and unknown statistical significance and instability of the results. We propose a randomization-based method to control the false positive rate and estimate statistical significance of the FCM results. Using this novel approach, we develop an fMRI activation detection method. The ability of the method in controlling the false positive rate is shown by analysis of false positives in activation maps of resting-state fMRI data. Controlling the false positive rate in FCM allows comparison of different fuzzy clustering methods, using different feature spaces, to other fMRI detection methods. In this paper, using simulation and real fMRI data, we compare a novel feature space that takes the variability of the hemodynamic response function into account (HRF-based feature space) to the conventional cross-correlation analysis and FCM using the cross-correlation feature space.

关键词： Fuzzy control Clustering methods Hemodynamics Clustering algorithms Brain Signal processing image processing Intelligent systems Process control Control systems

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Coding for fast access to image regions defined by pixel range

Coding for fast access to image regions defined by pixel ran...

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Data Compression Conference (DCC)

作者： A. Said S. Yea W.A. Pearlman Hewlett Packard Laboratories Palo Alto CA USA Center for Image Processing Research Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy NY USA

Many technical imaging applications, like coding "images" of digital elevation maps, require extracting regions of compressed images in which the pixel values are within a predefined range, and there is a need for coding methods that allow finding these regions efficiently, without having to decompress the whole image. A series of techniques to solve this problem is presented. First, it shows that many of the linear transforms commonly used for image compression can be used for that purpose by proving that the inclusion of nonlinear factors (like minimum or maximum pixel value in a block) does not render the transformation irreversible, and can be made to have very limited impact on the compression efficiency. For example, it shows how the "DC" coefficient of an 8/spl times/8 discrete cosine transform (DCT) can be replaced by the minimum or maximum in the 8/spl times/8 block. This result is valid for a large set of transforms, including the DCT, Walsh-Hadamard, and dyadic Haar transforms, and valid for any type of order-statistic filter output. Next, it shows the results also apply to the quantized transform coefficient cases as well as integer-to-integer transforms. The choices for coding the minimum and maximum values simultaneously, while providing quick access to pixel range and efficient compression were finally studied.

关键词： image coding Pixel Discrete transforms Discrete cosine transforms Magnetic resonance imaging Nonlinear filters Laboratories image processing Systems engineering and theory Application software

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Multiple-mode Kalman filtering with node selection using bearings-only measurements

Multiple-mode Kalman filtering with node selection using bea...

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Southeastern Symposium on System Theory

作者： Qiang Le L.M. Kaplan J.H. McClellan CTSPS Department of Engineering Clark Atlanta University Atlanta GA USA Center for Signal and Image Processing School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA

This work investigates multiple-mode tracking method with node selection using bearings-only measurements. We combine multiple-mode extended Kalman filter with node resource management to conserve energy while tracking a maneuvering target. Experiments using real data show that the MM adapts quicker to target maneuvers than the realizable single-mode tracker. Additional experiments show that the simplex node selection leads to better geolocation performance compared to the closest node selection when the number of active nodes is set to two.

关键词： Kalman filters Filtering Target tracking Resource management Batteries Military computing Intelligent sensors Direction of arrival estimation Electric variables measurement Signal processing

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Dynamic training of hand gesture recognition system

Dynamic training of hand gesture recognition system

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International Conference on Pattern Recognition

作者： A. Licsar T. Sziranyi Department of Image Processing and Neurocomputing University of Veszprém Veszprem Hungary Analogical & Neural Computing Laboratory Computer & Automation Research Institute Hungarian Academy of Sciences (ATOMKI) Budapest Hungary

We developed an augmented reality tool for vision-based hand gesture recognition in a camera-projector system. Our recognition method uses modified Fourier descriptors for the classification of static hand gestures. Hand segmentation is based on a background subtraction method, which is improved to handle background changes. Most of the recognition methods are trained and tested by the same service-person, and training phase occurs only preceding the interaction. However, there are numerous situations when several untrained users would like to use gestures for the interaction. In our new practical approach the correction of faulty detected gestures is done during the recognition itself. Our main result is the quick on-line adaptation to the gestures of a new user to achieve user-independent gesture recognition.

关键词： computer displays Cameras Fault detection Mice Hardware Phase detection System testing Feedback Auditory displays image processing

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Direction-of-arrival estimation of wideband sources using arbitrary shaped multidimensional arrays

Direction-of-arrival estimation of wideband sources using ar...

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

作者： Yeo-Sun Yoon L.M. Kaplan J.H. McClellan Center for Signal and Image Processing School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA CTSPS Department of Engineering Clark Atlanta University Atlanta GA USA

We generalize a new incoherent wideband direction-of-arrival (DOA) estimation algorithm that provides higher resolution than traditional incoherent techniques. The new method is able to better adjust its beam response when multiple sources are present than incoherent MUSIC. The original algorithm was designed to work strictly for an uniform linear array. In this paper, we demonstrate how to generalize the algorithm to work over arbitrary 1D or 2D arrays. We demonstrate the higher resolution of the new algorithm against incoherent MUSIC for 1D and 2D arrays using simulations of two source signals.

关键词： Direction of arrival estimation Wideband Multidimensional systems Frequency estimation Matrix decomposition Narrowband Multiple signal classification Sensor arrays Signal resolution Wireless communication

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Feature selection using genetic algorithm and it's application to face recognition

Feature selection using genetic algorithm and it's applicati...

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IEEE Conference on Cybernetics and Intelligent Systems

作者： M.T. Harandi M.N. Ahmadabadi B.N. Araabi C. Lucas Institute of Studies in Theoretical Physics and Mathematics Tehran Iran Control and Intelligent Processing Center of Excellence Department of Electrical and Computer Engineering University of Tehran Tehran Iran

A new method for feature selection based on generic algorithm and its application in face recognition is proposed. Simulation results show the superior performance of the proposed algorithm over the eigenface original method. In comparison to evolutionary pursuit method, the proposed method has a faster training phase and the ability of finding and searching more features using our novel fitness function

关键词： Genetic algorithms Face recognition Face detection Humans Principal component analysis Application software Analysis of variance Character recognition Process control Intelligent control

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