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

作者： Tian-Hu Yu S.K. Mitra Department of Electrical and Computer Engineering Signal and Image Processing Laboratory University of California Santa Barbara CA USA

An algorithm that removes impulse noise in images using a modified dynamic programming method is outlined. The restoration process combines two operations. In the first operation, the pixels corrupted by impulse noise are detected by a dynamic programming based searching strategy. In the second operation, the original gray levels of the noisy pixels are estimated by a linear interpolation or extrapolation approach. A separable process is used to detect the noisy pixels of the images. In order to preserve the details of the images and reduce the computational complexity of conventional dynamic programming, two modifications have been developed. One is called neighborhood searching with an adaptive figure of merit and the other is called overlapping block processing. The actual performance of the proposed technique is compared with that of the commonly used median filter by filtering noise-corrupted images. Some computational considerations are also discussed.< >

关键词： Dynamic programming Image restoration Noise level Interpolation Extrapolation Pixel Computational complexity Filters Filtering

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Stability, projection, and convergence of SMM for insufficient order adaptive IIR filters

Stability, projection, and convergence of SMM for insufficie...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： M. Nayeri H. Fan Department of Electrical Engineering Adaptive Signal Processing Laboratory Michigan State University East Lansing MI USA Department of Electrical and Computer Engineering University of Cincinnati Cincinnati OH USA

The stability of the SMM (Steiglitz-McBride method) in the underparameterized case is studied. It is shown that the offline SMM can potentially produce intermediate unstable estimates. A projection technique is introduced and analytically shown to overcome such instability. The existence of multiple stable equilibria for the SMM in the underparametrized case is demonstrated.< >

关键词： Stability Convergence IIR filters Adaptive filters signal processing algorithms Iterative algorithms System identification Adaptive signal processing Filtering algorithms Postal services

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Digital processing of color images

Digital processing of color images

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Human Vision, Visual processing, and Digital Display 1989

作者： Mitra, Sanjit K. Zarrinnaal, Iraj Wang, Yao Signal and Image Processing Laboratory Department of Electrical and Computer Engineering University of California Santa BarbaraCA93106 United States

Digital processing of black and white images has received most attention during the last 25 years, and has led to various algorithms for the enhancement, smoothing, and zooming of images. Due to the decreasing cost and increasing availability of color image acquisition and display equipment along with the computing systems of higher performance, it is expected that the digital processing of color images will rapidly grow in demand. In this paper we review our experiences with the processing of color images. In particular, algorithms for the contrast enhancement, smoothing and zooming of color images are investigated. The effects of applying these methods in color coordinates other than RGB are examined and considerations with respect to performance, time efficiency and compatibility with some popular algorithms developed for monochrome images are discussed. © 1989 SPIE. All rights reserved.

关键词： Color

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A nonlinear spectrum compression algorithm for the hearing impaired

A nonlinear spectrum compression algorithm for the hearing i...

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Annual Northeast Bioengineering Conference

作者： L.D. Paarmann M.D. Guiher Signal Processing Laboratory Department of Electrical and Computer Engineering Drexel University Philadelphia PA USA

A technique is proposed for increasing the speech intelligibility of persons with profound sensorineural hearing loss. The processing is based on a modification of the chirp-z transform that allows for nonlinear sampling along an arbitrary contour of the z-plane. Although the theory allows the nonlinear sampling to be arbitrary, an example showing that it is appropriate for nonlinear spectrum compression to aid the hearing-impaired is given. Samples are linearly spaced along the unit circle for a specified low-frequency segment; beyond the break-point the samples are nonlinearly spaced, perhaps spiraling inward to enhance spectral peaks, with the spacing width increasing with increasing frequency following an exponential function. A standard inverse DFT of these frequency samples returns the spectrum-compressed sequence. processing of continuous speech requires windowing and processing of data in a manner similar to the short-time Fourier transform (STFT). The authors present the theoretical basis for, and development of, the algorithm.< >

关键词： Compression algorithms Auditory system Sampling methods Speech processing Frequency signal processing algorithms Deafness Chirp Laboratories signal sampling

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Adaptive line enhancement using multirate techniques

Adaptive line enhancement using multirate techniques

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

作者： V.S. Somayazulu S.K. Mitra J.J. Shynk Signal & Image Processing Laboratory Department of Electrical & Computer Engineering University of California Santa Barbara CA USA

A novel structure for multirate adaptive filtering with lower computational complexity and improved performance of the adaptive algorithm is introduced. It uses auxiliary subbands and a modified filter bank with decimated subbands. It avoids the aliasing distortions encountered in critically decimated overlapping filter banks as well as the spectral gaps in nonoverlapping filter banks. The authors show that this structure has a lower computational complexity than previously reported structures. computer simulations are included showing the improvement in performance that can be achieved with the new structure operating as an adaptive line enhancer (ALE) compared with the conventional ALE.< >

关键词： Adaptive filters Finite impulse response filter Filter bank Computational complexity Convergence Line enhancers Narrowband Adaptive algorithm Echo cancellers Teleconferencing

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Partial shape recognition: a landmark-based approach

Partial shape recognition: a landmark-based approach

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IEEE International Conference on Systems, Man and Cybernetics

作者： N. Ansari E.J. Delp Center for Communications and Signal Processing Electrical and Computer Engineering Department New Jersey Institute of Technology Newark NJ USA Computer Vision and Image Processing Laboratory School of Electrical Engineering Purdue University IN USA

A technique to guide landmark matching known as hopping dynamic programming is described. The location of the model in the scene is estimated with a least-squares fit. A heuristic measure is then computed to decide if the model is in the scene. The shape features of an object are the landmarks associated with the object. The landmarks of an object are defined as the points of interest of the object that have important shape attributes. Examples of landmarks are corners, holes, protrusions, and high-curvature points.< >

关键词： Shape measurement Layout computer vision Pattern recognition signal processing Image processing Laboratories Performance evaluation Least squares approximation Feature extraction

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Parameter extraction of microwave transistors using tree annealing

Parameter extraction of microwave transistors using tree ann...

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IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits

作者： M.B. Steer G.L. Bilbro R.J. Trew S.G. Skaggs High Frequency Electronics Laboratory and the Center for Communications and Signal Processing Department of Electrical and Computer Engineering North Carolina State University Raleigh NC USA

The authors have developed an alternative formulation of simulated annealing using a tree-based Metropolis procedure called tree annealing. Tree annealing is suited to continuous optimization problems and, in particular, to transistor parameter extraction. The tree annealing optimization algorithm was used to extract the parameters of the HBT (heterojunction bipolar transistor) of U.K. Mishra et al. (IEDM Tech. Dig., p.180-3, Dec. 1988) using a physically based equivalent circuit and deembedded scattering parameter measurements from 45 MHz to 26.5 GHz. Good results were obtained from the parameter extraction technique, and the ability of MFA not to be locked in local minima enabled a physically based equivalent circuit model to be used. Tree annealing is essentially a smart random search technique and so requires many more functional evaluations than do gradient-based minimization algorithms. However, no startling guess is required, and the bounds on parameter values can be widely separated with little effect on optimization time.< >

关键词： Parameter extraction Microwave transistors Simulated annealing Equivalent circuits Combinatorial mathematics Robustness Frequency Laboratories Microwave communication signal processing

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Simulated hearing loss as a baseline for the assessment of auditory function in cochlearly impaired listeners

Simulated hearing loss as a baseline for the assessment of a...

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Annual Northeast Bioengineering Conference

作者： S. Buus M. Florentine Center for Communication and Digital Signal Processing (416 DA) Department of Electrical and Computer Engineering Northeastern University Boston MA USA Communication Research Laboratory (226 FR) Department of Speech-Language Pathology and Audiology Northeastern University Boston MA USA

An overview is presented of results obtained in listeners with real and simulated impairments. Spectral processing is assessed by psychoacoustical tuning curves and growth-of-masking functions; temporal processing is assessed by temporal integration and gap detection thresholds. When comparisons are made to normal listeners tested in the quiet, impaired listeners generally show deficits on all these tasks. When the comparisons are made to simulated impairments, some impaired listeners show no deficits, whereas others still show deficits. These results indicate that abnormal intensity perception is responsible for some, but not all, of impaired listeners' apparent deficits in spectral and temporal processing. In many cases, however, it appears that spectral and temporal processing, per se, are altered in the impaired auditory system.< >

关键词： Deafness Psychoacoustic models Ear Frequency Auditory system Tuning Acoustic noise Noise shaping Testing Spectral shape

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INTERFERENCE-TOLERANT TIME-DIFFERENCE-OF-ARRIVAL ESTIMATION FOR MODULATED signalS

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IEEE TRANSACTIONS ON ACOUSTICS SPEECH AND signal processing 1988年第9期36卷 1385-1395页

作者： GARDNER, WA CHEN, CK Signal and Image Processing Laboratory Department of Electrical Engineering and Computer Science University of California슠Davis Davis CA USA Signal and Image Processing Laboratory Department of Electrical Engineering and Computer Science University of California Davis Davis CA USA

A method for estimation of the difference in the times of arrival of wavefronts of two separate sensors is introduced. The method, called SPECCORR, exploits the spectral correlation property, called spectral coherence, that essentially all modulated signals exhibit to obtain estimates that are highly tolerant to severely corruptive noise and interference. This tolerance is explained theoretically and demonstrated with simulations.< >

关键词： Interference Time difference of arrival Noise measurement Narrowband Autocorrelation Direction of arrival estimation Antenna measurements Design methodology signal design

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signal INTERCEPTION - A UNIFYING THEORETICAL FRAMEWORK FOR FEATURE DETECTION

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IEEE TRANSACTIONS ON COMMUNICATIONS 1988年第8期36卷 897-906页

作者： GARDNER, WA Signal and Image Processing Laboratory Department of Electrical Engineering and Computer Science University of California Davis CA USA

The unifying framework of the spectral-correlation theory of cyclostationary signals is used to present a broad treatment of weak, random signal detection for interception purposes. The relationships among a variety of previously proposed ad hoc detectors, optimum detectors, and newly proposed detectors are established. The spectral-correlation-plane approach to the interception problem is put forth as especially promising for detection, classification, and estimation in particularly difficult environments involving unknown and changing noise levels and interference activity. A fundamental drawback of the popular radiometric methods in such environments is explained.< >

关键词： computer vision signal processing signal detection Radiometry Detectors Random processes Noise level Interference Image processing Satellite broadcasting

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