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Pacific Rim Conference on Lasers and Electro-Optics (CLEO/Pacific Rim)

作者： T.-C. Poon Optical Image Processing Laboratory Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University Blacksburg VA USA

Driven by potential applications in military, biology, robot navigation and other areas, various methods for optical pattern recognition have been proposed and studied over the past decades. The key feature in current real-time optical pattern recognition systems among these methods is the use of a spatial light modulator (SLM) at the Fourier transform plane in the so-called joint-Fourier transform correlation (JTC) system [C.S Weaver et al. (1966)]. We propose a novel hybrid (optical/electronic) processing technique to achieve real-time joint-transform correlation. The technique employs acousto-optic heterodyne scanning [T.-C. Poon et al., 1979] and it does not require a SLM at the Fourier plane as in other conventional real-time JTC systems. This departure from the conventional scheme is extremely important, as it does not depend on SLM design considerations and issues such as phase uniformity and contrast ratio. The effectiveness of the novel proposed system will be demonstrated with some experimental results. Future work will be focused on exploring scale-invariant, rotation-invariant and multiobject joint-transform correlation with this hybrid optical pattern recognition method.

关键词： Optical mixing Biomedical optical imaging Optical modulation Pattern recognition Real time systems Fourier transforms Image processing Application software Military computing Biology

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Comparison of time-frequency analysis performance on hearts and murmurs

Comparison of time-frequency analysis performance on hearts ...

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Student Conference on Research and Development (SCOReD)

作者： S. Daliman A.Z. Sha'ameri Digital Signal Processing Laboratory Department of Microelectronics and Computer Engineering Faculty of Electrical Engineering Universiti Teknologi Malaysia Johor Malaysia Dept of Microelectronics and Computer Engineering Universiti Teknologi Malaysia Malaysia

Time-frequency analysis is one of the methods to deal with non-stationary and time-varying signal such as heart sounds and murmurs. Wigner-Ville distribution (WVD) is a popular tool to obtain time-frequency representation of signal. Windowed Wigner-Ville distribution (WWVD) and smooth windowed Wigner-Ville distribution (SWWVD) are the improvement method to overcome the problem faced by WVD. Determination of parameter setting of WWVD and SWWVD eliminates the cross-terms and improve time-frequency representation. The accuracy of time-frequency representation of simulated heart sounds and murmurs are compared and determined based on the mainlobe width, peak-to-sidelobe average ratio and signal-to-interference ratio. It is found that the most accurate time-frequency representation can be obtained using the SWWVD.

关键词： Time frequency analysis Heart Kernel Signal analysis Frequency estimation Digital signal processing Microelectronics Acoustical engineering Signal processing Auditory system

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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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How to effectively utilize information to design hyperspectral target detection and classification algorithms

How to effectively utilize information to design hyperspectr...

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IEEE Workshop on Advances in Techniques for Analysis of Remotely Sensed Data

作者： Chein-I Chang Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD USA

ISBN: (纸本)0780383508

Hyperspectral imagery offers a means of uncovering enormous spectral information that can be used for various applications in data exploitation. How effectively such information is used affects the way image analysis algorithms are designed. In this paper, we take up this issue and focus on algorithms designed and developed for target detection and classification in hyperspectral imagery. In order to effectively characterize the information available before and after the data are processed, the a priori information and a posteriori information are used in accordance with how the information is obtained. A piece of information is referred to as a priori information if it is provided by known knowledge before data are processed. On the other hand, a piece of information is referred to as a posteriori information if it is unknown a priori, but can be obtained directly from the data in an unsupervised fashion during the course of data processing. Since a priori information is known beforehand, it can be further decomposed into two types of information, desired and undesired a priori information. The desired a priori information is the knowledge that will assist, improve and enhance data analysis, whereas the undesired a priori information is the knowledge that hinders, interferes or destructs analysis during data processing. This paper investigates how these three types of information play their roles in design and development of several hyperspectral target detection and classification algorithms. Experiments are also conducted to validate their utility.

关键词： Algorithm design and analysis Object detection Classification algorithms Hyperspectral imaging Data processing Data analysis Hyperspectral sensors Image analysis Information analysis Interference constraints

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Non-coherent estimator-correlators for unresolved multipath Ricean channels

Non-coherent estimator-correlators for unresolved multipath ...

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IEEE Conference on Vehicular Technology (VTC)

作者： F. Danilo-Lemoine H. Leib Department of Syst. and Computer Engineering Broadband Communications & Wireless Systems Centre Carleton University Ottawa ONT Canada Department of Electrical and Computer Engineering McGill University Telecommunications and Signal Processing Laboratory Montreal QUE Canada

This paper considers detection techniques for unresolved Ricean/Rayleigh fading multipath channels. It is well known that the optimal receiver has an estimator-correlator form, with a minimum mean-square error (MMSE) estimate. With known multipath delays and unknown specular phases, the Ricean non-coherent multipath channel is a case where the received noiseless signal process is non-Gaussian, and the MMSE estimator is non-linear in the observation. This work presents novel, explicit expressions for such a MMSE estimator. It is shown that the MMSE estimate has the same multipath format as the noiseless received signal, with the unknown parameters replaced by corresponding estimates. The MMSE estimator scales down contributions from specular multipath components with poor phase estimates, reducing their effect on the detection process. The estimator includes a multipath decorrelation operation which is essential to avoid error floors over unresolved multipath channels. Based on matched filter bounds, it is shown that little degradation gains are obtained by employing suboptimal linear estimator-correlators, provided that they include the decorrelation operation.

关键词： Multipath channels Phase estimation Delay estimation Decorrelation Rayleigh channels Phase noise Signal processing Phase detection Matched filters Degradation

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Blind equalization of communication sequences based on optimization of cumulant criteria

Blind equalization of communication sequences based on optim...

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IEEE Conference on Wireless Communications and Networking

作者： Hsiao-Chun Wu Dongxin Xu Communications and Signal Processing Laboratory Department of Electrical and Computer Engineering Louisiana State University Baton Rouge LA USA BBN Technologies GTE Cambridge MA USA

Blind equalization draws a lot of attention. Several statistical objective functions such as kurtosis and constant modulus were based on the noise-free model and hence their ISI cancellers were sensitive to noise. In this paper, a unifying adaptive blind equalization method is proposed, which can be robust to noise than the current cumulant-based adaptive methods. Our new objective functions can be applied for wired or wireless i.i.d. communication symbols with noise. The simulation shows that our new method outperforms the kurtosis-based method when the background noise exists.

关键词： Blind equalizers Probability density function Signal processing Finite impulse response filter Laboratories Delay Linear approximation Gaussian noise Sufficient conditions Taylor series

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Analysis of heart sounds based on continuous wavelet transform

Analysis of heart sounds based on continuous wavelet transfo...

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Student Conference on Research and Development (SCOReD)

作者： Z.M. Zin S.H. Salleh S. Daliman M.D. Sulaiman Digital Signal Processing Laboratory Department of Microelectronics and Computer Engineering Faculty of Electrical Engineering Universiti Teknologi Malaysia Skudai Malaysia Cardiology Unit Department of Medicine Faculty of Medicine Universiti Kebangsaan Malaysia Kuala Lumpur Malaysia

This paper presents the application of wavelet transform analysis method to the heart sounds signal. The heart sounds is a non-stationery signal, thus it is very important to study the frequency and time information. One of the time-frequency analysis methods is short time Fourier transforms. However, the STFT analysis is limited by the time and frequency resolution. The wavelet transform was introduced to curb the resolution problem in STFT. The wavelet transform is a multi-resolution time-scale analysis that gives high resolution for low frequency components and low resolution for high frequency components. Since majority of heart sounds component lies in low frequency, thus the application of wavelet transform to heart sounds is very suitable. Results in time-frequency representation clearly show that the wavelet transform is capable to distinguish between the normal with a few types of abnormal heart sounds. The murmurs caused by particular heart diseases such as aortic regurgitation, aortic stenosis, mitral regurgitation, mitral stenosis, pulmonary regurgitation and tricuspid regurgitation were clearly shown under continuous wavelet representation.

关键词： Continuous wavelet transforms Heart Wavelet analysis Wavelet transforms Signal resolution Signal analysis Fourier transforms Time frequency analysis Cardiac disease Stethoscope

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Accuracy of ultra-short heart rate variability measures

Accuracy of ultra-short heart rate variability measures

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

作者： T. Thong K. Li J. McNames M. Aboy B. Goldstein Department of Biomedical Engineering OGI School of Science & Engineering Oregon Health and Sciences University Beaverton OR USA Biomedical Signal Processing Laboratory Department of Electrical & Computer Engineering Portland State University Portland OR USA Department of Pediatrics Oregon Health and Sciences University Portland OR USA

Heart rate variability (HRV) measures have been used to assess autonomic cardiac regulation. The standard lengths used in HRV analyses are 5 minutes and 24 hours. In this paper we investigated the accuracy of three HRV measures for ultra-short record length, 10 seconds, which is the length of standard electrocardiograms. The measures chosen were: Standard Deviation Normal-Normal (SDNN), Root Mean Square of Successive Differences (RMSSD), frequency of the peak of the high-frequency (HF) spectra derived using a non-parametric spectrum method. Our analyses indicated that the RMSSD(10)s would be consistent estimates of the 5 minute RMSSD(300)s. The SDNN(10)s were found not to be accurate in our analyses. The HF peak, while promising, would require further studies.

关键词： Heart rate variability Neural networks Measurement standards Time measurement Biomedical measurements Electrocardiography Histograms Biomedical engineering Laboratories Root mean square

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Paroxysmal atrial fibrillation prediction using isolated premature atrial events and paroxysmal atrial tachycardia

Paroxysmal atrial fibrillation prediction using isolated pre...

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

作者： T. Thong J. McNames M. Aboy B. Goldstein Department of Biomedical Engineering OGI School of Science & Engineering Oregon Health and Sciences University Beaverton OR USA Biomedical Signal Processing Laboratory Department of Electrical & Computer Engineering Portland State University Portland OR USA Department of Pediatrics Oregon Health and Sciences University Portland OR USA

A simplified predictor of episodes of paroxysmal atrial fibrillation (PAF) is presented. Over a thirty minute monitoring time, the number of premature atrial complexes (PAC) without normal sinus node reset is counted. When the number of such PACs changes by more than 2 over the monitoring period, a PAF prediction is made. The PAC test is supplemented with a paroxysmal atrial tachycardia (PAT) test that uses a similar approach in identifying and counting episodes of PAF. The combined PAC and PAT test yields a sensitivity of 68%, a specificity of 86% and a positive predictivity of 86% on the public test PAF database from the 2001 computer in Cardiology.

关键词： Atrial fibrillation Databases Testing Biomedical engineering Cardiology Batteries computerized monitoring Medical treatment Rhythm Electrocardiography

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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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