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

作者： R.A. Jesinger V.L. Stonick Department of Electrical and Computer Engineering and the Biomedical Engineering Program Carnegie Mellon University Pittsburgh PA USA

Presents a new technique for reconstruction and imaging of volumetric neuromuscular activity using digital signal processing of multichannel surface potential recordings. Magnetic resonance imaging is used to chart anatomical structures and quantify material permittivity within the inhomogenous volume. Array signal processing is used localize neuromuscular action potentials based on the available anatomical and electromyographic measurements. Poisson's equation is then solved using finite element methods coupled with signal processing estimation techniques. This new imaging tool can greatly enhance clinical diagnosis and treatment of neuromuscular injuries and disorders by localizing pathological signals within muscle.< >

关键词： Neuromuscular Electrodes Magnetic resonance imaging Magnetic materials Array signal processing Image reconstruction Digital signal processing Surface reconstruction Digital magnetic recording Anatomical structure

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Microwave Absorption in NaCl Crystals with Various Controlled Defect Conditions

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MRS Online Proceedings Library 1994年第1期347卷 467-472页

作者： Binshen Meng John Booske Reid Cooper Sam Freeman Department of Electrical and Computer Engineering University of Wisconsin Madison USA Department of Materials Science and Engineering University of Wisconsin Madison USA Materials Science Program Madison University of Wisconsin Madison USA

A thorough understanding of fundamental microwave absorption mechanisms in ionic crystalline solids is important for microwave sintering of ceramics, as well as the design of high speed electronic packaging, advanced radomes, etc. Of particular importance to these applications are how the density and type of crystalline defects affect the dominant microwave absorption mechanisms. We have designed experiments to measure microwave absorption in NaCl samples with controlled variations in defect conditions(pure, point defects, dislocations and grain boundaries) at different temperatures (20-400 °C) and frequencies (2-20 GHz). Initial results are reported and discussed.

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Array processing for hand-held scanners

Array processing for hand-held scanners

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IEEE Symposium (IUS) Ultrasonics

作者： M. Karaman Pai-Chi Li Pai-Chi Li M. O'Donnell Electrical Engineering and Computer Science Department and Bioengineering Program University of Michigan Ann Arbor MI USA

Multi-element synthetic aperture imaging methods suitable for applications with severe cost and size limitations are explored. Array apertures are synthesized using an active multi-element receive subaperture and a multi-element defocused transmit subaperture. The performance of multi-element methods has been tested and compared to conventional imagers through measurements with a 3.5 MHz, 128-element transducer array on different gel phantoms. The multi-element synthetic aperture methods achieve higher electronic signal to noise ratio and better contrast resolution than conventional synthetic aperture techniques, approaching conventional phased array performance

关键词： Biomedical acoustic imaging Acoustic arrays Array signal processing Biomedical signal processing Acoustic signal processing Acoustic beam focusing

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Non-orthogonal Gabor representation of biological signals

Non-orthogonal Gabor representation of biological signals

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

作者： M.L. Brown W.J. Williams A.O. Hero Bioengineering Program Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA

A new technique for modelling biological signals as a linear combination of non-orthogonal Gabor logons is described. The technique has been applied to two types of signals, event-related potentials (ERPs) and temporomandibular joint (TMJ) clicks. Examination of time-frequency representations of these signals revealed that they appear to consist of a small number of localized energy concentrations. Attempts to capture this apparent low dimensionality with the standard orthogonal Gabor expansion and the standard wavelet transform were unsuccessful. However, the non-orthogonal Gabor decomposition method described in this paper provides a compact, accurate signal representation and the parameters provide a good basis for ERP category and TMJ click classification.< >

关键词： Enterprise resource planning Time frequency analysis Signal processing Solid modeling Biological system modeling Pattern classification Biomedical engineering Electronic mail Biology Wavelet transforms

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A laser scattering method for characterization of thromboemboli in whole blood

A laser scattering method for characterization of thromboemb...

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

作者： J. Kim J.C. Lin L.O. Reynolds Bioengineering Program Electrical Engineering and Computer Science Department Deceased University of Illinois Chicago Chicago IL USA

An optical scattering method, which measures the size, number, and type of microemboli located in flowing whole blood, is described. A perturbation solution to the one speed radiative transport equation is used to model the scattering geometry. The approximate two-parameter phase function is used to investigate scattering characteristics of microemboli. The nature of microemboli is determined by comparing the scattered intensity ratio in two forward directions, while the size and number are determined by considering intensities scattered perpendicularly to the incident direction. This method has been tested with several sizes of polystyrene spheres, air bubbles, and blood dots. The results showed excellent agreement with calculations.

关键词： Light scattering Particle scattering Detectors Red blood cells Equations Geometrical optics Laser theory Biomedical engineering Biological materials Monitoring

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Semi-automatic morphological measurements of 2-D and 3-D microvascular images

Semi-automatic morphological measurements of 2-D and 3-D mic...

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IEEE International Conference on Image Processing

作者： F.A. Merchant S.J. Aggarwal K.R. Diller A.C. Bovik Biomedical Engineering Program University of Texas Austin Austin TX USA Department of Electrical and Computer Engineering University of Texas Austin Austin TX USA

The technique of serial optical sectioning by laser scanning confocal microscopy (LSCM), in conjunction with off-line digital image analysis, was used to quantize the morphological changes occurring during angiogenesis and revascularization of pancreatic islets transplanted at the renal subcapsular site in rats. The process consisted of in-vivo imaging of the microvasculature which was optically enhanced by the administration of a fluorescent probe into the circulating blood. Serial two-dimensional (2-D) optical sections were obtained through the vascular bed at varying z-intervals in order to perform a computer reconstruction of the complete three-dimensional (3-D) morphology. Image processing algorithms such as gray level thresholding, median filtering, skeletonization, region labeling and template matching were applied to compute the vessel density, lengths and diameters of the neovasculature, and the tortuosity index.< >

关键词： Optical filters Optical microscopy Laser transitions Digital images Image analysis Pancreas Rats Optical imaging Fluorescence Probes

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A comparison between H-infinity/Mu-synthesis control and sliding-mode control for robust control of a small autonomous underwater vehicle

A comparison between H-infinity/Mu-synthesis control and sli...

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Symposium on Autonomous Underwater Vehicle Technology (AUV)

作者： C.L. Logan Department of Electrical Engineering and Computer Science MIT Sea Grant College Program Massachusetts Institute of Technology Cambridge MA

This paper presents a comparison of H/sub /spl infin////spl mu/-synthesis sliding-mode that was done for heading and depth control of the Draper Laboratory/MIT Sea Grant Sea Squirt autonomous underwater vehicle (AUV). The approximate decoupling of the AUV heading and depth dynamics allowed us to have decoupled heading and depth designs for both the H/sub /spl infin////spl mu/-synthesis and the sliding-mode methodologies. The H/sub /spl infin////spl mu/-synthesis based controllers and the sliding-mode based controllers were implemented and tested by using a simulation of the AUV full order nonlinear model (including thruster and sensor dynamics). We analyzed the performance of the controllers (for a simultaneous depth and maneuver) over the approximate range of axial velocities commanded by the AUV. The performance of the controllers in the face of additive sensor noise was also analyzed.

关键词： Sliding mode control H infinity control Robust control Underwater vehicles Control systems Remotely operated vehicles Vehicle dynamics Sensor systems Open loop systems Testing

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Reconstruction of dynamic 3-D structures of biological objects using stereo microscopy

Reconstruction of dynamic 3-D structures of biological objec...

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IEEE International Conference on Image Processing

作者： Wen-Hung Liao S.J. Aggarwal J.K. Aggarwal Computer and Vision Research Center Department of Electrical and Computer Engineering University of Texas Austin Austin TX USA Biomedical Engineering Program University of Texas Austin Austin TX USA

The authors address the analysis of three dimensional shape and shape change in nonrigid biological objects imaged via a stereo light microscope (SLM). Most existing stereo or motion analysis techniques cannot be applied to microscopic biological images because they usually lack salient features. The authors propose an integrated approach for the reconstruction of 3D structures and motion analysis for scenes where only a few informative features are available. The key components of this framework are: (1) image registration, (2) region-of-interest extraction, and (3) stereo and motion analysis using a cooperative spatial and temporal matching process. The authors describe these three stages of processing and illustrate the efficacy of the proposed approach using real images of a live frog's ventricle. The reconstructed dynamic 3-D structures of the ventricle are demonstrated in the authors' experimental results.< >

关键词： Scanning electron microscopy Stereo vision Image reconstruction Biology computing computer vision Motion analysis Shape measurement Image analysis Image registration Biomedical measurements

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Timing specifications and accuracy of the real-time 3D echocardiographic reconstruction system

Timing specifications and accuracy of the real-time 3D echoc...

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IEEE International Conference on Image Processing

作者： R. Desai J.C. Buckey J.A. Pearce Department of Electrical and Computer Engineering Biomedical Engineering Program University of Texas Austin Austin TX USA U.T. Southwestern Medical Center Dallas USA

We analyze the performance of the real-time system for 3D reconstruction of cardiac structures from successive 2D B-scan ultrasound images acquired using the Tilt Echo technique, developed by Buckey et al. (1987, 1993). This system is used to evaluate cardiac performance parameters such as stroke volume and ventricular mass. The design of such a real-time system involves consideration of two features, viz. the accuracy of the 3D reconstructions generated by the system, and the timing behavior of the system. We describe the procedure to test the accuracy of the system and present results to demonstrate the accuracy of reconstruction. We analyze the timing behavior of the system based on simulations using Modechart. We verify that the system design satisfies the real-time constraints.< >

关键词： Timing Accuracy Real time systems Image reconstruction Ultrasonic imaging Hardware Biomedical engineering Biomedical imaging Echocardiography Image analysis

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Raman Scattering and X-Ray Diffraction Studies of Gallium Nitride Films Grown on (100) Gallium Arsenide

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MRS Online Proceedings Library 1994年第1期339卷 503-508页

作者： S. W. Brown S. C. Rand C.-H. Hong D. Pavlidis University of Michigan Applied Physics Program Ann Arbor USA Department of Electrical Engineering and Computer Science University of Michigan Solid State Electronics Laboratory Ann Arbor USA

Raman spectroscopy and x-ray diffraction are used to characterize Gallium Nitride (GaN) films grown on (100) Gallium Arsenide (GaAs) substrates. Reflection X-ray diffraction data from (200) planes of GaAs and cubic GaN are presented. The linewidth of the cubic GaN diffraction peak is shown to be a strong function of the growth temperature. Raman spectra are presented for a series of samples grown at different temperatures. Raman scattering is characterized by strong peaks at 560 cm-1 and at 736 cm-1, corresponding to TO and LO phonon modes of cubic GaN, respectively. An additional, unexplained feature at 768 cm-1 is clearly observed in Raman spectra of c-GaN samples grown at lower temperatures. The polarization dependence of the intensity of the GaN LO phonon mode is presented and compared with the GaAs LO phonon mode to establish the relative orientation of the c-GaN epitaxy on GaAs.

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