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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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A robust RBF neural net Bayesian estimator for channel equalization

A robust RBF neural net Bayesian estimator for channel equal...

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International Symposium on Communications Control and Signal processing (ISCCSP)

作者： D. Khedim A. Benyettou M. Woolfson SIgnal-IMage-PArole (SIMPA) Laboratory Department of Computer Science University of Science and Technology of Oran Oran Algeria Signal processing laboratory Department E.E. Engineering University of Nottingham Nottingham UK

The characteristic (transfer function) of a dispersive M-ary channel equalizer designed through a Bayesian estimator, a performance indicator that is not trivial to obtain for M>2 due to intersymbol interference (ISI), is investigated. A set of curves is obtained and interpreted. Implementation through a radial basis function neural network is considered. It is shown that because network centers endure updating with different rates, the equalizer characteristic errates off the optimum, causing thus the symbol error rate and/or the training time to increase. A solution, based on incorporating an underlying symmetry in the channel response levels into the updating algorithm, brings the characteristic uniformly closer to the optimal one. It is also provided a strategy endowing the network with self-initializing. Simulation results are presented for a channel with sufficient ISI strength.

关键词： Robustness Neural networks Bayesian methods Equalizers Dispersion Intersymbol interference Additive noise Delay estimation Laboratories Error analysis

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Modified lifting algorithm and VLSI architecture for the 9/7 wavelet filters

Modified lifting algorithm and VLSI architecture for the 9/7...

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International Conference on Machine Learning and Cybernetics (ICMLC)

作者： Chen-Gyi Xiong Zhi-Rong Gao Jin-Wen Tian Jian Liu The State Key Laboratory of Education Commission for Image Processing and Intelligent Control Institute of Pattern Recognition & Artificial Intelligence Huazhong University of Science and Technology Wuhan China Department of Computer Science Wuhan University of Science and Engineering Hebei China

ISBN: (纸本)0780384032

A new parallel-based lifting algorithm (PBLA) for the 9/7 filters, exploring the parallelism of arithmetic operations in each lifting step, was proposed in this paper. It shortened significantly the critical path of computation, and resulted in a fast VLSI implementation architecture. In comparison with the conventional lifting algorithm based implementation (CLABI), the latency is reduced by more than half from (4T/sub m/ + 8T/sub a/) to (T/sub m/ + 4T/sub a/), which is competitive to that of convolution based implementation CBI, and can be further reduced to Tm by inserting 3 stages of pipeline. The experimental results demonstrate that the proposed architecture has good performances in both speed and area.

关键词： Very large scale integration Discrete wavelet transforms Filters image coding Delay Parallel processing Arithmetic Convolution Hardware Transform coding

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Normal mammogram classification based on a support vector machine utilizing crossed distribution features

Normal mammogram classification based on a support vector ma...

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Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

作者： W. Chiracharit Y. Sun P. Kumhom K. Chamnongthai C. Babbs E.J. Delp Electronics and Telecom. Engineering Department King Mongkut's University of Technology Thonburi Bangkok Thailand Video and Image Processing Laboratory School of Electrical and Computer Engineering Purdue University IN USA Department of Basic Medical Sciences School of Veterinary Medicine Purdue University IN USA

Automatic classification of normal mammograms, which constitute a majority of screening mammograms, is a new approach to computer-aided diagnosis of breast cancer. This approach may be limited, however, by non-separable "crossed" distributions of features that are extracted from digitized mammograms. This work presents a method of mapping such non-separable input features into a new set of separable features that can be utilized, together with ordinary "uncrossed" features, by a support vector machine (SVM) classifier. The results of the proposed scheme show improved performance with 80% sensitivity and 95% specificity.

关键词： Support vector machines Support vector machine classification Training data Data mining Biomedical engineering Biomedical imaging computer aided diagnosis Breast cancer Aging Mammography

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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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Adaptive directional zerotree image coding

Adaptive directional zerotree image coding

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： S. Jirachawang V. Areekul Manufacturing Automation Section National Electronics and Computer Technology Center Klong Luang Pathum Thani Thailand Kasetsart Image Processing Laboratory (KIP Lab) Department of Electrical Engineering Kasetsart University Bangkok Thailand

In this paper, adaptive directional zerotree image coding is introduced. This modified SPIHT algorithm called adaptive directional SPIRT (ADSPIHT) exploits an appropriate quadtree structure in order to take advantage from horizontal and vertical edge encoding in separable wavelet transform. Moreover, this adaptive algorithm changes structure in order to enhance energy compaction without increasing side information rate. Compared to SPIRT and DSPIHT, ADSPIHT improves coding performance in PSNR, especially in images with highly vertical and horizontal edges.

关键词： image coding PSNR Wavelet transforms Compaction Degradation Energy capture Energy resolution Arithmetic Manufacturing automation computer aided manufacturing

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Automatic face region tracking for highly accurate face recognition in unconstrained environments

Automatic face region tracking for highly accurate face reco...

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IEEE Conference on Advanced Video and Signal Based Surveillance (AVSS)

作者： Y.-O. Kim J. Paik Jingu Heo A. Koschan B. Abidi M. Abidi Korea Electronics and Technology Institute Puchon Gyeonggi South Korea Image Processing Laboratory Department of Image Engineering Graduate School of Advanced Imaging Science Multimedia and Film Chung-Ang University Seoul South Korea Imaging Robotics and Intelligent Systems Laboratory Department of Electrical and Computer Engineering University of Tennessee Knoxville USA

We present a combined real-time face region tracking and highly accurate face recognition technique for an intelligent surveillance system. High-resolution face images are very important to achieving accurate identification of a human face. Conventional surveillance or security systems, however, usually provide poor image quality because they use only fixed cameras to record scenes passively. We have implemented a real-time surveillance system that tracks a moving face using four pan-tilt-zoom (PTZ) cameras. While tracking, the region-of-interest (ROI) can be obtained by using a low-pass filter and background subtraction with the PTZ. Color information in the ROI is updated to extract features for optimal tracking and zooming. FaceIt/sup /spl reg//, which is one of the most popular face recognition software packages, is evaluated and then used to recognize the faces from the video signal. Experimentation with real human faces showed highly acceptable results in the sense of both accuracy and computational efficiency.

关键词： Face recognition Surveillance Real time systems Humans Cameras Intelligent systems Security image quality Layout Low pass filters

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Multiple objects segmentation based on maximum-likelihood estimation and optimum entropy-distribution (MLE-OED)

Multiple objects segmentation based on maximum-likelihood es...

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International Conference on Pattern Recognition

作者： Xie Jun H.T. Tsui Xia Deshen Image Processing and Computer Vision Laboratory Department of Electronic Engineering Chinese University of Hong Kong Hong Kong China Pattern Recognition Laboratory Department of Computer Science Nanjing University of Science and Technology China

ISBN: (纸本)076951695X

A new method based on MLE-OED is proposed for unsupervised image segmentation of multiple objects which have fuzzy edges. It adjusts the parameters of a mixture of Gaussian distributions via minimizing a new loss function proposed to implement image segmentation based on the image's local spatial information and global intensity distribution properties. The loss function consists of two terms: a local content fitting term, which optimizes the entropy distribution, and a global statistical fitting term, which maximizes the likelihood of the parameters for the given data. The proposed segmentation method was validated by simulated and real examples. The performance in the experiments is better than those of two popular methods.

关键词： Object segmentation Maximum likelihood estimation image segmentation Layout Uncertainty image edge detection Shape measurement image processing Pattern recognition Gaussian distribution

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Automatic thresholding abundance fractional images for mixed pixel classification

Automatic thresholding abundance fractional images for mixed...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Shao-Shan Chiang Chein-I Chang Department of Electrical Engineering Lunghwa University of Science and Technology Taoyuan Taiwan Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore MD USA

Mixed pixel classification is different from spatial-based image classification in the sense that the former deals with abundance fractional images resulting from mixed pixels as opposed to classification maps produced by the latter. As a result, mixed pixel classification is generally carried out by visual inspection on the generated abundance fractional images. Consequently, it can be very subjective and vary with different human interpretations. Under such circumstance, it is difficult to substantiate an algorithm and conducting a comparative analysis is impossible. This paper presents one histogram-based approach to thresholding abundance fractional images. It thresholds an abundance fractional image into a binary image using a probability of confidence as a threshold value.

关键词： Pixel Humans image analysis Inspection image segmentation Signal processing image processing Laboratories computer science image classification

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image fusion using multiresolution analysis

Image fusion using multiresolution analysis

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Jong-Hyun Park Kyoung-Ok Kim Young-Kyu Yang Remote Sensing Team Image Processing Department ETRI Computer and Software Technology Laboratory Taejon South Korea

The objective of this study is to propose multiresolution data fusion scheme using multiresolution analysis (MRA). Three techniques compared, respectively based on Haar wavelet basis (HWB), Daubechies wavelet basis (DWB), and IHS transform. Daubechies wavelet basis (DWB) is far more efficient than the HWB and IHS transform, thus establishing the advantages for data fusion of formally multiresolution analysis. DWB is best for image sharpening and to maintain the information of original data. Especially, Daubechies wavelet basis is able to enhance image sharpening and preserve spectral information.

关键词： image fusion Multiresolution analysis Wavelet analysis Remote sensing Discrete wavelet transforms Satellites Wavelet coefficients Spatial resolution Wavelet transforms Spectral analysis

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