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Signal Processing Letters, IEEE

Issue 12 • Date Dec. 2004

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Displaying Results 1 - 19 of 19
  • Table of contents

    Publication Year: 2004 , Page(s): c1
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  • IEEE Signal Processing Letters publication information

    Publication Year: 2004 , Page(s): c2
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  • An iterative procedure for removing random-valued impulse noise

    Publication Year: 2004 , Page(s): 921 - 924
    Cited by:  Papers (53)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (896 KB) |  | HTML iconHTML  

    This work proposes a two-stage iterative method for removing random-valued impulse noise. In the first phase, we use the adaptive center-weighted median filter to identify pixels which are likely to be corrupted by noise (noise candidates). In the second phase, these noise candidates are restored using a detail-preserving regularization method which allows edges and noise-free pixels to be preserved. These two phases are applied alternatively. Simulation results indicate that the proposed method is significantly better than those using just nonlinear filters or regularization only. View full abstract»

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  • New algorithm for modulated complex lapped transform with symmetrical window function

    Publication Year: 2004 , Page(s): 925 - 928
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    An algorithm for the fast computation of modulated complex lapped transform (MCLT) with symmetrical window function is proposed. The method is based on two discrete cosine transforms (DCTs), two stages of butterfly operations and additional multiplications. The real or imaginary part of the MCLT coefficients can be independently obtained from one of the two blocks of DCT coefficients. The proposed algorithm not only reduces the computational complexity compared with previous algorithms, but also has regular architecture which is suitable for hardware implementations. View full abstract»

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  • Parallel recursive computation of the inverse Legendre moment transforms for signal and image reconstruction

    Publication Year: 2004 , Page(s): 929 - 932
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (128 KB) |  | HTML iconHTML  

    The inverse Legendre moment transform plays an important role in the field of image analysis applications. A recursive algorithm based on Clenshaw's recurrence formula is derived for the fast computation of the inverse Legendre moment transform for signal and image reconstruction purposes. The reconstruction can be implemented effectively using recursive equations. The presented algorithm is particularly suitable for parallel very large-scale integrated circuit (VLSIC) implementation due to its regular, modular, and simple filter structure. View full abstract»

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  • A new fast bit-reversal permutation algorithm based on a symmetry

    Publication Year: 2004 , Page(s): 933 - 936
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (136 KB) |  | HTML iconHTML  

    This correspondence describes a new bit-reversal permutation algorithm based on a trivial symmetry that has not been exploited until now. According to timing experiments, this algorithm outperforms the fastest algorithms known to the author. This is of interest for applications using intensive fast Fourier transforms (or fast Hartley transforms) of constant length, such as transform domain adaptive filtering. View full abstract»

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  • Wavelet-based denoising with nearly arbitrarily shaped windows

    Publication Year: 2004 , Page(s): 937 - 940
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB) |  | HTML iconHTML  

    The estimation of the signal variance in a noisy environment is a critical issue in denoising. The signal variance is simply but effectively obtained by the locally adaptive window-based maximum likelihood or the maximum a posteriori estimate. The size of the locally adaptive window is also an important factor in estimating the signal variance. In this letter, we propose a novel algorithm for determining the variable size of the locally adaptive window using a region-based approach. A region including a denoising point is partitioned into disjoint subregions. The locally adaptive window for denoising is obtained by selecting the proper subregions. In our method, a nearly arbitrarily shaped window is achieved for image denoising. The experimental results show that our method outperforms other critically sampled wavelet denoising schemes. View full abstract»

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  • Efficient tracking of cyclic human motion by component motion

    Publication Year: 2004 , Page(s): 941 - 944
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB) |  | HTML iconHTML  

    A set of techniques are presented for Bayesian tracking of cyclic human motion based on decomposing a complex cyclic motion into component motions. Phases of the component motions are defined and two different mechanisms for coupling the phases are described: importance sampling and an observation model. The intensity of coupling is adaptively adjusted during tracking such that strong coupling is triggered during self-occlusion. Tracking of a walking human using motion decomposition and phase coupling is performed with an improved particle filter called the approximate kernel particle filter. We show that our approach handles foreign object occlusion and self-occlusion with improved accuracy and efficiency compared with conventional tracking without decomposition. View full abstract»

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  • On OFDM systems with spatially correlated antennas in low multipath diversity situations

    Publication Year: 2004 , Page(s): 945 - 947
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB) |  | HTML iconHTML  

    Spatial correlation is introduced when antennas are not well separated, which typically leads to performance degradation in space diversity systems for flat fading wireless channels. However, in a frequency-selective environment with orthogonal frequency division multiplexing (OFDM), multipath diversity can help in overcoming this performance degradation. This is due to transformation of a highly spatially correlated channel impulse response to less spatially correlated channel frequency response inherently by an OFDM system in the presence of multipath diversity . In this letter, we numerically evaluate the minimum antenna separation required for a target spatial correlation in the frequency domain in situations with low multipath diversity. Performance results for two highly spatially correlated receive antennas with such spacing are provided for low multipath diversity channels and it is found to be within 1 dB (at BER=10-3) of spatially uncorrelated reception for QPSK modulation. View full abstract»

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  • Space-time coded multi-transmission among distributed transmitters without perfect synchronization

    Publication Year: 2004 , Page(s): 948 - 951
    Cited by:  Papers (129)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    For mobile users without antenna arrays, transmission diversity can be achieved with cooperative space-time encoded transmissions. However, a challenge is the lack of perfect synchronization on delay, timing and carrier frequency of distributed transmitters, which destroys the required space-time signal structure. In this letter, a new transmission scheme is proposed which employs distributed space-time block codes to achieve full diversity while tolerating imperfect synchronization. It is promising in distributed wireless networks such as sensor networks both to enhance transmission energy efficiency and to reduce synchronization cost. View full abstract»

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  • Optimal mode selection for a pulsed-quality dual-frame video coder

    Publication Year: 2004 , Page(s): 952 - 955
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB) |  | HTML iconHTML  

    A dual-frame video coder employs two past reference frames for motion compensated prediction. Compared to conventional single frame prediction, the dual-frame encoder can have advantages both in distortion-rate performance and in error resilience. In previous work, it was shown that optimal mode selection can enhance the performance of a dual-frame encoder. In another strand of previous work, it was shown that uneven assignment of quality to frames, to create high-quality (HQ) long-term reference frames, can enhance the performance of a dual-frame encoder. In this letter, we combine these two strands and demonstrate the performance advantages of optimal mode selection among HQ frames for video transmission over noisy channels. View full abstract»

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  • Estimation of speech presence probability in the field of microphone array

    Publication Year: 2004 , Page(s): 956 - 959
    Cited by:  Papers (13)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (848 KB) |  | HTML iconHTML  

    The subject of this work is the robust estimation of speech presence probability of every spectral component of a speech signal impinging on a linear microphone array. The approach is based on the generalized likelihood ratio test (GLRT) applied to the multichannel framework and far-field, wideband sources. It is shown that under certain distributional assumptions the GLRT provides a framework for speech presence detection by exploiting both the spatial localization and spectral content of the speech signal. The efficiency of the approach and its superiority over a state-of-the-art one-channel speech presence estimation technique is illustrated when additive white Gaussian noise is present in the acoustical field in low signal-to-noise ratio (SNR). View full abstract»

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  • List of reviewers

    Publication Year: 2004 , Page(s): 960 - 966
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  • IEEE Signal Processing Letters Information for authors

    Publication Year: 2004 , Page(s): 967 - 968
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  • Special issue on genomic signal processing

    Publication Year: 2004 , Page(s): 969
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  • 2005 IEEE Signal Processing Society membership application

    Publication Year: 2004 , Page(s): 970
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  • 2004 Index

    Publication Year: 2004 , Page(s): 971 - 996
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  • IEEE Signal Processing Society Information

    Publication Year: 2004 , Page(s): c3
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  • Blank page [back cover]

    Publication Year: 2004 , Page(s): c4
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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
Peter Willett
University of Connecticut
Storrs, CT 06269
peter.willett@uconn.edu