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Acoustics, Speech and Signal Processing, IEEE Transactions on

Issue 5 • Date October 1986

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Displaying Results 1 - 25 of 46
  • [Front cover and table of contents]

    Publication Year: 1986 , Page(s): 0
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    Freely Available from IEEE
  • Comments on "A general method of minimum cross-entropy spectral estimation"

    Publication Year: 1986 , Page(s): 1324 - 1326
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    In a recent correspondence Tzannes et al. [1] introduced a new form of minimum cross-entropy (MCE) spectral analysis based on the observation that normalized spectra and symmetric probability density functions (pdf's) are axiomatically indistinguishable. Thus, the form of the minimum cross-entropy posterior pdf can be used as a model for spectral estimation. In this correspondence we derive the same result without using a Lagrange multiplier methodology. We also establish the connection of this estimate to the cepstral representation of the signal and propose an efficient algorithm not requiring explicit solution of nonlinear equations. View full abstract»

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  • Corrections to "Results on nonrecursive digital filters with nonequidistant taps"

    Publication Year: 1986 , Page(s): 1336
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    First Page of the Article
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  • Radar data processing: Vol. I - Introduction and tracking

    Publication Year: 1986 , Page(s): 1350 - 1351
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    First Page of the Article
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  • [Back cover]

    Publication Year: 1986 , Page(s): c4
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    Freely Available from IEEE
  • An analysis of the distributed arithmetic digital filter

    Publication Year: 1986 , Page(s): 1165 - 1170
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB)  

    Distributed arithmetic filters have been shown to be an effective method of implementing linear shift-invariant filters. In this paper, the overall roundoff error budgets of admissible distributed arithmetic filter structures are compared to conventional lumped parameter and to each other. In addition, dynamic range considerations are also introduced into the study. View full abstract»

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  • Morphological skeleton representation and coding of binary images

    Publication Year: 1986 , Page(s): 1228 - 1244
    Cited by:  Papers (121)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2048 KB)  

    This paper presents the results of a study on the use of morphological set operations to represent and encode a discrete binary image by parts of its skeleton, a thinned version of the image containing complete information about its shape and size. Using morphological erosions and openings, a finite image can be uniquely decomposed into a finite number of skeleton subsets and then the image can be exactly reconstructed by dilating the skeleton subsets. The morphological skeleton is shown to unify many previous approaches to skeletonization, and some of its theoretical properties are investigated. Fast algorithms that reduce the original quadratic complexity to linear are developed for skeleton decomposition and reconstruction. Partial reconstructions of the image are quantified through the omission of subsets of skeleton points. The concepts of a globally and locally minimal skeleton are introduced and fast algorithms are developed for obtaining minimal skeletons. For images containing blobs and large areas, the skeleton subsets are much thinner than the original image. Therefore, encoding of the skeleton information results in lower information rates than optimum block-Huffman or optimum runlength-Huffman coding of the original image. The highest level of image compression was obtained by using Elias coding of the skeleton. View full abstract»

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  • Optimization of one-bit full adders embedded in regular structures

    Publication Year: 1986 , Page(s): 1289 - 1300
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1136 KB)  

    We study the problem of optimizing the transistor sizes in the one-bit nMOS full adder either isolated or embedded in a regular array. A local optimization method that we call the critical-path optimization method is developed. In this method, two parameters at a time are changed along the critical path until a locally optimal choice of transistor sizes is found. The critical-path optimization method uses the Berkeley VLSI tools and the hierarchical layout language ALLENDE developed at Princeton. First, we optimize the isolated one-bit full adder implemented in three ways: as a PLA, data selector, and with random logic. The details of the critical-path optimization method and power-time tradeoff curves are illustrated here. Second, we optimize the one-bit full adder embedded in a simple array multiplier. The entire 3 × 3, 4 × 4, 8 × 8, and 10 × 10 multipliers are optimized and their local optima are compared. Because the optimization of the entire circuit becomes less practical when the circuit becomes larger, we develop a method that makes use of circuit regularity. We prove that some small array of one-bit full adders, called the canonical configuration, has the same local optima as the n × n multiplier for large n, with the criterion of minimizing the delay time T. Hence, we can greatly reduce the computation load by optimizing this canonical configuration instead of optimizing the entire circuit. Experimental results confirm the effectiveness of this approach. View full abstract»

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  • Detection of wave reflectors and wave sources in the earth subsurface

    Publication Year: 1986 , Page(s): 1245 - 1257
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1088 KB)  

    Event detection is a very important task in geophysics. It encompasses the detection of wave sources (earthquakes, subsurface explosions) and the detection of wave reflectors (interfaces between rock layers having different velocities and/or different densities). The latter application is very important in seismic oil prospecting. Seismic events release energy which propagates toward the earth surface as waves which are recorded by arrays of sensors. The data recorded are usually corrupted by noise, which sometimes is much stronger than the weak events. The aim of this paper is to couple wave theory and detection theory to detect seismic events in an optimal way. A statistical model of the earth is proposed. This model combined with the wave equation describes sufficiently well the wave propagation in the stratified earth. Optimal and suboptimal receivers for event detection, based on this earth model, are proposed. The validity of our approach is demonstrated by simulation examples. View full abstract»

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  • A multimicroprocessor architecture for real-time computation of a class of DFT algorithms

    Publication Year: 1986 , Page(s): 1301 - 1309
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1152 KB)  

    The design of a multimicroprocessor system intended for a class of real-time processing applications is discussed. The applications considered require the computation of a subset of an N-input Fourier transform under the assumption of a serial data input. The suitability of two different algorithms and the corresponding parallel architectures is analyzed and compared. More specifically, we compare the computation of the FFT algorithms on an SIMD (single instruction multiple data) machine to the implementation of the DFT algorithm on an MISD (multiple instruction single data) machine. Our results indicate that the latter is better suited for the targeted applications. An actual operational MISD computer, implemented with off-the-shelf microprocessors intended for one of the targeted applications, is described. View full abstract»

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  • A modification of the Kumaresan-Tufts methods for estimating rational impulse responses

    Publication Year: 1986 , Page(s): 1336 - 1338
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    This correspondence presents a modification of the Kumaresan-Tufts algorithm for estimating the parameters of rational impulse responses in additive white noise. The modified algorithm uses the forward and backward predictors to select the signal poles, and then combines the two sets of poles to form the final estimates. The modified algorithm exhibits an improved robustness and a smaller bias in some test cases. View full abstract»

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  • Some new aspects of filters for filter banks

    Publication Year: 1986 , Page(s): 1182 - 1200
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (976 KB)  

    The present paper deals with the design of filters for use in filter banks, i.e., with certain constraints on their transition bands. The goal is to achieve a baseband frequency response of a back-to-back analysis/synthesis filter bank system that is ideally flat in magnitude and linear in phase. Using the proposed method, this is possible for conventional polyphase filter banks, single-sideband (SSB) filter banks, and generalized quadrature mirror filter (GQMF) banks. The method provides several options, one of them even yielding subsystems with linear phase. In contrast to most previous approaches to this topic, the described design procedure is an analytical one and is not based on optimizations or iterative algorithms. Furthermore, two families of window sequences are proposed for use in the design procedure mentioned above, but are also suitable for any windowed Fourier filter design. View full abstract»

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  • Simple, effective computation of principal eigenvectors and their eigenvalues and application to high-resolution estimation of frequencies

    Publication Year: 1986 , Page(s): 1046 - 1053
    Cited by:  Papers (47)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB)  

    We present the results of an investigation of the Prony-Lanczos (P-L) method [14], [38] and the power method [39] for simple computation of approximations to a few eigenvectors and eigenvalues of a Hermitian matrix. We are motivated by realization of high-resolution signal processing in an integrated circuit. The computational speeds of the above methods are analyzed. They are completely dependent on the speed of a matrix-vector product operation. If only a few eigenvalues or eigenvectors are needed, the suggested methods can substitute for methods of the LINPACK or EISPACK subroutine libraries. The accuracies of the suggested methods are evaluated using matrices formed from simulated data consisting of two sinusoids plus Gaussian noise. Comparisons are made to the corresponding eigenvalues and eigenvectors obtained using LINPACK as a reference. Also, the accuracies of frequency estimates obtained from the eigenvectors are compared. View full abstract»

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  • Analysis of the error in the reconstruction of N-dimensional stochastic processes

    Publication Year: 1986 , Page(s): 1326 - 1329
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    This correspondence derives a frequency domain expression for the error in the reconstruction of an N-dimensional stochastic process from its uniformly distributed samples when the reconstruction technique of Petersen and Middleton is used with an arbitrary reconstruction filter. View full abstract»

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  • On the performance of signal-subspace processing-- Part I: Narrow-band systems

    Publication Year: 1986 , Page(s): 1201 - 1209
    Cited by:  Papers (63)  |  Patents (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (800 KB)  

    This paper presents an analytical evaluation of detection (determination of the number of sources) and estimation performances of narrow-band signal-subspace processing for multiple-source direction finding. The probabilities of underestimating and overestimating the number of sources are derived, under asymptotic conditions and around the threshold regions, in terms of the choice of a penalty function and signal, noise, and array parameters for the cases of at most two closely spaced sources in the spatially white noise. A scalar measure is introduced for the evaluation of the quality of the estimated signal subspace. Based on the statistics of this measure, performance thresholds are demonstrated for the signal-to-noise ratio, angle separation, and correlation between two equipowered sources. View full abstract»

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  • ESPRIT--A subspace rotation approach to estimation of parameters of cisoids in noise

    Publication Year: 1986 , Page(s): 1340 - 1342
    Cited by:  Papers (294)  |  Patents (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    The application of a subspace invariance approach (ESPRIT) to the estimation of parameters (frequencies and powers) of cisoids in noise is described. ESPRIT exploits an underlying rotational invariance of signal subspaces spanned by two temporally displaced data sets. The new approach has several advantages including improved resolution over Pisarenko's technique for harmonic retrieval. View full abstract»

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  • A ring array processor architecture for highly parallel dynamic time warping

    Publication Year: 1986 , Page(s): 1310 - 1318
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1032 KB)  

    A ring array architecture is studied on a hardware algorithm and a control scheme for dynamic time warping (DTW) processing, in order to achieve real-time speech recognition. For developing a practical DTW processor, the key factors are to reduce the number of processing elements (PE's) in the array architecture and to maintain highly efficient concurrency and high throughput. Regular data and control flow is achieved by using a ring network, where every constituent PE uses parallel and pipelined operations on the data. Regular and continuous DTW processing, even for a variety of treated data volume, is realized with a novel control scheme based on "tags" and "status flags" attached to the data, thus indicating data attributes. This control scheme permits a simple control structure to be achieved for the array system. The efficiency and throughput expected for the ring array architecture is then compared to orthogonal array architecture. View full abstract»

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  • Analysis/Synthesis filter bank design based on time domain aliasing cancellation

    Publication Year: 1986 , Page(s): 1153 - 1161
    Cited by:  Papers (153)  |  Patents (94)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (832 KB)  

    A single-sideband analysis/synthesis system is proposed which provides perfect reconstruction of a signal from a set of critically sampled analysis signals. The technique is developed in terms of a weighted overlap-add method of analysis/synthesis and allows overlap between adjacent time windows. This implies that time domain aliasing is introduced in the analysis; however, this aliasing is cancelled in the synthesis process, and the system can provide perfect reconstruction. Achieving perfect reconstruction places constraints on the time domain window shape which are equivalent to those placed on the frequency domain shape of analysis/synthesis channels used in recently proposed critically sampled systems based on frequency domain aliasing cancellation [7], [8]. In fact, a duality exists between the new technique and the frequency domain techniques of [7] and [8], The proposed technique is more efficient than frequency domain designs for a given number of analysis/synthesis channels, and can provide reasonably band-limited channel responses. The technique could be particularly useful in applications where critically sampled analysis/synthesis is desirable, e.g., coding. View full abstract»

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  • Measurement of spectral correlation

    Publication Year: 1986 , Page(s): 1111 - 1123
    Cited by:  Papers (75)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1296 KB)  

    Various methods for measurement/computation of spectral correlation functions for time series that exhibit cyclostationarity are described in a unifying theoretical framework. Some of these are amenable to digital hardware or software implementations, others are amenable to analog electrical or optical implementations, and other implementation types used for conventional spectral analysis are also possible. The interaction among reliability and temporal, spectral, and cycle resolutions is determined. Novel problems of computational complexity, cycle leakage and aliasing, cycle resolution, and cycle phasing are discussed. Sample spectral correlation functions are calculated with digital software for several simulated signals. View full abstract»

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  • Separating multipaths by global optimization of a multidimensional matched filter

    Publication Year: 1986 , Page(s): 1029 - 1037
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (840 KB)  

    A transmitted signal can arrive at a receiver via several refracted Fermat paths. If the paths are independent in the Fresnel sense, then the received signal can be modeled as the sum of amplitude scaled and time shifted copies of a predetermined replica plus white noise. We present an algorithm that uses the replica to determine the time shifts and amplitudes for each path. It is referred to as an n-dimensional matched filter algorithm by analogy with the well-known matched filter algorithm. The cross correlation between the received signal and the replica oscillates near the center frequency of the transmitted signal. This causes the n-dimensional matched filter output to have many local maxima that are not globally optimal. The time shifts and amplitude scalings for the Fermat paths are determined by maximizing the output of the n-dimensional matched filter. The algorithm is more robust and efficient than others currently available. Simulated realizations of received signals were generated with multipath and noise characteristics similar to an ocean acoustic transmission case. These realizations were then separated into arrival times and corresponding amplitudes by the algorithm. The results of these tests and the general limitations of the algorithm are discussed. View full abstract»

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  • Broad-band beamforming and the generalized sidelobe canceller

    Publication Year: 1986 , Page(s): 1322 - 1323
    Cited by:  Papers (16)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    This correspondence identifies general conditions under which the generalized sidelobe canceller (GSC) structure implements a linearly constrained minimum variance (LCMV) broad-band beam-former. In previously published work, conditions have been presented for the case in which the linear constraint is restricted to fixed gain in the steer direction. Here, that work is extended to include general linear constraints. A geometric interpretation is presented to provide insight into the relationship between the GSC structure and LCMV beamformers, and several recent developments in broad-band beam-forming are reviewed and related to the GSC structure. View full abstract»

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  • The design of uniformly and nonuniformly spaced pseudoquadrature mirror filters

    Publication Year: 1986 , Page(s): 1090 - 1096
    Cited by:  Papers (74)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (728 KB)  

    In the past, quadrature mirror filters (QMF's) have been used to derive both uniformly and nonuniformly spaced filterbanks. A pair of QMF's divides a signal into two equal bands which can be decimated at 2:1 and subsequently combined to reconstruct the original signal. In order to derive filterbanks with more than two bands, QMF's are combined in a binary tree structure. Pseudoquadrature mirror filters are similar to QMF's but can be designed to split a signal directly into any number of equally spaced bands, thus generalizing the QMF concept. In this paper, the theory of pseudoquadrature mirror filters is reviewed. These filters retain the desirable property that the channel signals from a uniformly spaced bank of M filters can be decimated by M:1, then interpolated and reassembled to reproduce the original signal. An extension is made to the theory to allow a set of nonuniformly spaced filters to be derived from a uniformly spaced set and still retain all the desirable characteristics. Another extension to the theory is the derivation of a family of different sized filterbanks, all derived from the same original prototype. Potential applications for the new filterbanks include improvements in subband coding of speech and music, and analog scrambling of speech. View full abstract»

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  • Implementation of adaptive array algorithms

    Publication Year: 1986 , Page(s): 1038 - 1045
    Cited by:  Papers (51)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (776 KB)  

    Some new, efficient, and numerically stable algorithms for the recursive solution of matrix problems arising in optimal beam-forming and direction finding are described and analyzed. The matrix problems considered are systems of linear equations and spectral decomposition. While recursive solution procedures based on the matrix inversion lemma may be unstable, ours are stable. Furthermore, these algorithms are extremely fast. View full abstract»

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  • A complex adaptive algorithm for IIR filtering

    Publication Year: 1986 , Page(s): 1342 - 1344
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    This correspondence generalizes the Gauss-Newton algorithm [1] for adaptive IIR filters to include complex coefficients. The resulting algorithm simultaneously updates the real and imaginary parts of the filter coefficients to minimize the average squared estimation error. It has application in frequency-domain adaptive IIR filtering [2] where the signals and filter coefficients are complex. View full abstract»

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  • Nonlinear space-variant postprocessing of block coded images

    Publication Year: 1986 , Page(s): 1258 - 1268
    Cited by:  Papers (137)  |  Patents (30)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2256 KB)  

    An important application of spatial filtering techniques is in the postprocessing of images degraded by coding. Linear, space-invariant filters are inadequate to reduce the noise produced by block coders. The noise in block coded images is correlated with the local characteristics of the signal, and such filters are unable to exploit this correlation to reduce the noise. We propose a new nonlinear, space-variant filtering algorithm which smooths jagged edges without blurring them, and smooths out abrupt intensity changes in monotone areas. Edge sharpness is preserved because near edges the filtering of the signal is negligible. Consequently, in-band noise is not reduced, but the well-known masking effect reduces the visibility of this in-band noise. The algorithm is only slightly more complex to implement than simple linear filtering. We present examples of processed images and SNR figures to demonstrate that a significant improvement in subjective and objective quality is achieved. View full abstract»

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Aims & Scope

This Transactions ceased production in 1990. The current retitled publication is IEEE Transactions on Signal Processing.

Full Aims & Scope