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IEEE Signal Processing Letters

Issue 8 • Date Aug. 1997

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Displaying Results 1 - 9 of 9
  • Detection of microcalcifications in mammograms using higher order statistics

    Publication Year: 1997, Page(s):213 - 216
    Cited by:  Papers (30)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (83 KB)

    A new method for detecting microcalcifications in mammograms is described. In this method, the mammogram image is first processed by a subband decomposition filterbank. The bandpass subimage is divided into overlapping square regions in which skewness and kurtosis as measures of the asymmetry and impulsiveness of the distribution are estimated. The detection method utilizes these two parameters. A... View full abstract»

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  • Exact multichannel blind image restoration

    Publication Year: 1997, Page(s):217 - 220
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (176 KB)

    Liu and Xu (see ibid., vol.43, no.11, p.2714-23, 1995) proposed a blind symbol estimation algorithm in digital communications. If all the channels are linear time-invariant finite impulse response (LTI FIR) filters, this algorithm can estimate symbols exactly when the channels and the input symbols satisfy some loose restrictions. We extend this algorithm to two dimensions, and in particular, to m... View full abstract»

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  • Using out-of-domain data to improve in-domain language models

    Publication Year: 1997, Page(s):221 - 223
    Cited by:  Papers (19)  |  Patents (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (75 KB)

    Standard statistical language modeling techniques suffer from sparse data problems when applied to real tasks in speech recognition, where large amounts of domain-dependent text are not available. We investigate new approaches to improve sparse application-specific language models by combining domain dependent and out-of-domain data, including a back-off scheme that effectively leads to context-de... View full abstract»

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  • Computation-constrained fast MPEG-2 encoding

    Publication Year: 1997, Page(s):224 - 226
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (55 KB)

    We introduce a computation-constrained predictive motion estimation algorithm for fast Motion Picture Expert Group-2 (MPEG-2) encoding. Motion estimation is restricted to a relatively small search area whose center is a two-dimensional (2D) median predicted motion vector. The number of computations is further reduced by incorporating explicitly a computational constraint during the estimation proc... View full abstract»

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  • Robust EZW image coding for noisy channels

    Publication Year: 1997, Page(s):227 - 229
    Cited by:  Papers (44)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (37 KB)

    We present a new embedded zerotree wavelet image coding algorithm that is based on the algorithms developed by Shapiro (see IEEE Trans. Signal Processing, Spec. Issue Wavelets Signal Processing, vol.41, no.12, p.3445-62, 1993) and Said et al. (see IEEE Trans. Circuits Syst. Video Technol., vol.6, no.6, p.243-50, 1996). Our algorithm features a relatively simple coding structure and provides a bett... View full abstract»

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  • A pseudoinverse update algorithm for rank-reduced covariance matrices from 2-D data

    Publication Year: 1997, Page(s):230 - 231
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (78 KB)

    A number of algorithms have a higher resolution than the common beamformer. These often require the calculation of a pseudoinverse of a matrix, which makes the algorithm very slow for repeated applications. We consider updating the pseudoinverse for window motions either in time or in space for two-dimensional (2-D) data taken from a linear array. Our results are shown to reduce the computational ... View full abstract»

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  • A note on most favorable array geometries for DOA estimation and array interpolation

    Publication Year: 1997, Page(s):232 - 235
    Cited by:  Papers (41)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (148 KB)

    Given an n-element linear array with the fixed positions x/sub 1/ and x/sub n/ of the leftmost and rightmost array sensors, it is shown that the stochastic Cramer-Rao bound (CRB) and MUSIC performance depend on positions of the remaining n-2 sensors within the interval [x/sub 1/, x/sub n/]. The asymptotic performance of the interpolated array approach shows similar dependence. The most favorable g... View full abstract»

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  • Automatic bound estimation: a practical development in optimal bounding ellipsoid processing

    Publication Year: 1997, Page(s):236 - 239
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (95 KB)

    Practical application of optimal bounding ellipsoid identification is made possible by the optimal bounding ellipsoid algorithm with automatic bound estimation (OBE-ABE), which automatically estimates model error bounds. Lack of tenable bounds in many real problems has rendered these interesting new methods impractical. OBE-ABE is consistently convergent under proven conditions, and offers signifi... View full abstract»

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  • Exploring lag diversity in the high-order ambiguity function for polynomial phase signals

    Publication Year: 1997, Page(s):240 - 242
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (123 KB)

    High-order ambiguity function (HAF) is an effective tool for retrieving coefficients of polynomial phase signals (PPSs). The lag choice is dictated by conflicting requirements: a large lag improves estimation accuracy but drastically limits the range of the parameters that can be estimated, By using two (large) coprime lags and solving linear Diophantine equations using the Euclidean algorithm, we... View full abstract»

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Aims & Scope

The IEEE Signal Processing Letters is a monthly, archival publication designed to provide rapid dissemination of original, cutting-edge ideas and timely, significant contributions in signal, image, speech, language and audio processing.

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Meet Our Editors

Editor-in-Chief
Peter Willett
University of Connecticut
Storrs, CT 06269
peter.willett@uconn.edu