IEEE Signal Processing Letters

Issue 3 • March 2002

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Displaying Results 1 - 8 of 8
  • Context modeling for near-lossless image coding

    Publication Year: 2002, Page(s):77 - 80
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (228 KB) | HTML iconHTML

    This letter describes a context-based entropy coding suitable for any causal spatial differential pulse code modulation (DPCM) scheme performing lossless or near-lossless image coding. The proposed method is based on partitioning of prediction errors into homogeneous classes before arithmetic coding. A context function is measured on prediction errors lying within a two-dimensional (2-D) causal ne... View full abstract»

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  • A universal image quality index

    Publication Year: 2002, Page(s):81 - 84
    Cited by:  Papers (1828)  |  Patents (39)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (248 KB) | HTML iconHTML

    We propose a new universal objective image quality index, which is easy to calculate and applicable to various image processing applications. Instead of using traditional error summation methods, the proposed index is designed by modeling any image distortion as a combination of three factors: loss of correlation, luminance distortion, and contrast distortion. Although the new index is mathematica... View full abstract»

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  • Performance evaluation and comparison of G.729/AMR/fuzzy voice activity detectors

    Publication Year: 2002, Page(s):85 - 88
    Cited by:  Papers (36)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (202 KB) | HTML iconHTML

    The paper proposes a performance evaluation and comparison of G.729, AMR, and fuzzy voice activity detection (FVAD) algorithms. The comparison was made using objective, psychoacoustic, and subjective parameters. A highly varied speech database was also set up to evaluate the extent to which VADs depend on language, the signal-to-noise ratio (SNR), or the power level. View full abstract»

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  • On the N-dimensional extension of the discrete prolate spheroidal window

    Publication Year: 2002, Page(s):89 - 91
    Cited by:  Papers (18)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (211 KB) | HTML iconHTML

    The optimal one-dimensional (1-D) window, an index-limited sequence with maximum energy concentration in a finite frequency interval, is related to a particular discrete prolate spheroidal sequence. This letter presents the N-dimensional (N-D) extension, i.e., the N-D window with limited support and maximum energy concentration in a general nonseparable N-D passband. These windows can be applied t... View full abstract»

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  • Analysis and classification of time-varying signals with multiple time-frequency structures

    Publication Year: 2002, Page(s):92 - 95
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (242 KB) | HTML iconHTML

    We propose a time-frequency (TF) technique designed to match signals with multiple and different characteristics for successful analysis and classification. The method uses a modified matching pursuit signal decomposition incorporating signal-matched dictionaries. For analysis, it uses a combination of TF representations chosen adaptively to provide a concentrated representation for each selected ... View full abstract»

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  • The centroid of the symmetrical Kullback-Leibler distance

    Publication Year: 2002, Page(s):96 - 99
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (223 KB) | HTML iconHTML

    This paper discusses the computation of the centroid induced by the symmetrical Kullback-Leibler distance. It is shown that it is the unique zeroing argument of a function which only depends on the arithmetic and the normalized geometric mean of the cluster. An efficient algorithm for its computation is presented. Speech spectra are used as an example. View full abstract»

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  • Blind channel estimation using first and second derivatives of the characteristic function

    Publication Year: 2002, Page(s):100 - 103
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (222 KB) | HTML iconHTML

    Traditionally, high-order statistics are used for blind estimation of nonminimum phase finite impulse response (FIR) channels. In this paper we present a new, alternative approach, that uses first- or second-order derivatives of the observations' second generalized characteristic function, evaluated at arbitrary (off-origin) locations. The estimation of these derivatives reduces plainly into speci... View full abstract»

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  • Frequency warping and the Mel scale

    Publication Year: 2002, Page(s):104 - 107
    Cited by:  Papers (15)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (212 KB) | HTML iconHTML

    We present experimental results that show that the scale-factor relating the formant frequencies of different speakers increases with decreasing values of formant frequency. Based on these results, we experimentally obtain a frequency warping function aimed at separating speaker dependencies from the inherent characterization of the sound. We find that the frequency warping function is similar to ... 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.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
James E. Fowler
Dept Electrical & Computer Engineering
Associate Director                         
Distributed Analytics and Security Institute
Mississippi State University
Mississippi State, MS 39762 USA
fowler@ece.msstate.edu