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Signal Processing Letters, IEEE

Issue 12 • Date Dec. 2005

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Displaying Results 1 - 25 of 25
  • Table of contents

    Publication Year: 2005 , Page(s): c1 - c4
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  • IEEE Signal Processing Letters publication information

    Publication Year: 2005 , Page(s): c2
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  • Discontinuity-embedded deformable models for surface reconstruction from range images

    Publication Year: 2005 , Page(s): 805 - 808
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB) |  | HTML iconHTML  

    Surface reconstruction is a critical step in three-dimensional image processing and understanding. In this letter, a discontinuity-embedded deformable model has been developed to model surfaces with discontinuities. Governed by the Lagrange motion equation, a finite-element representation of the model can dynamically fit the data in both continuous and discontinuous components, reaching its equilibrium in response to induced forces. Experimental results on synthetic and range images demonstrate a significant improvement in preserving depth discontinuities over conventional approaches. View full abstract»

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  • On the output SNR of the speech-distortion weighted multichannel Wiener filter

    Publication Year: 2005 , Page(s): 809 - 811
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB) |  | HTML iconHTML  

    In this letter, we prove that the output signal-to-noise ratio (SNR) after noise reduction with the speech-distortion weighted multichannel Wiener filter is always larger than or equal to the input SNR, for any filter length, for any value of the tradeoff parameter between noise reduction and speech distortion, and for all possible speech and noise correlation matrices. View full abstract»

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  • Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction

    Publication Year: 2005 , Page(s): 812 - 815
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB) |  | HTML iconHTML  

    Heart sounds (HS) obscure the interpretation of lung sounds (LS). This letter presents a new method to detect and remove this undesired disturbance. The HS detection algorithm is based on a recurrence time statistic that is sensitive to changes in a reconstructed state space. Signal segments that are found to contain HS are removed, and the arising missing parts are replaced with predicted LS using a nonlinear prediction scheme. The prediction operates in the reconstructed state space and uses an iterated integrated nearest trajectory algorithm. The HS detection algorithm detects HS with an error rate of 4% false positives and 8% false negatives. The spectral difference between the reconstructed LS signal and an LS signal with removed HS was 0.34±0.25, 0.50±0.33, 0.46±0.35, and 0.94±0.64 dB/Hz in the frequency bands 20-40, 40-70, 70-150, and 150-300 Hz, respectively. The cross-correlation index was found to be 99.7%, indicating excellent similarity between actual LS and predicted LS. Listening tests performed by a skilled physician showed high-quality auditory results. View full abstract»

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  • H adaptive filters for eye blink artifact minimization from electroencephalogram

    Publication Year: 2005 , Page(s): 816 - 819
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB) |  | HTML iconHTML  

    Two adaptive algorithms (time varying and exponentially weighted) based on the H principles are proposed for the minimization of electrooculogram (EOG) artifacts from corrupted electroencephalographic signals. Performance of the proposed algorithms are compared with the least-mean-square (LMS) algorithm. Improvements in the output signal-to-noise ratio along with time plots are used for the comparison. It is found that the H-based algorithms effectively minimize the EOG artifacts and always outperform the LMS algorithm. View full abstract»

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  • Turbo DFE algorithm with imperfect decision feedback

    Publication Year: 2005 , Page(s): 820 - 823
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB) |  | HTML iconHTML  

    In this letter, we propose a new turbo decision feedback equalizer (DFE) algorithm that takes into account decision feedback error propagation. We derive the exact mathematical expression for the probability density function (pdf) of soft decision feedback symbols, assuming that soft outputs from channel decoder are independent identically distributed Gaussian random variables with known mean and variance. We find a new set of "imperfect" turbo minimum mean-square error DFE coefficients based on the derived pdf. The proposed turbo detector outperforms other turbo equalization algorithms of similar computational complexity in terms of bit-error rate. The achieved improvement is up to 3.8 dB for severe frequency-selective channels. View full abstract»

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  • Low-complexity bit-allocation algorithm for MPEG AAC audio coders

    Publication Year: 2005 , Page(s): 824 - 826
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB) |  | HTML iconHTML  

    This letter presents a method for estimating the quantization noise introduced by a nonuniform quantizer, like those used in the family of MPEG-2/4 AAC audio coders. The method is generalized for the case of estimating the mean squared or the maximum value of the quantization noise. Its use will allow the bit-allocation algorithm to be adapted to different coding scenarios, depending on the available number of bits. Using the proposed method, it is possible to implement a loopless bit-allocation algorithm, without the need for using any kind of iteration loops. This helps to dramatically reduce the computational complexity of the bit-allocation algorithm, making it easier to implement in real-time applications where computational power is limited. View full abstract»

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  • A generalized MVDR spectrum

    Publication Year: 2005 , Page(s): 827 - 830
    Cited by:  Papers (36)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    The minimum variance distortionless response (MVDR) approach is very popular in array processing. It is also employed in spectral estimation where the Fourier matrix is used in the optimization process. First, we give a general form of the MVDR where any unitary matrix can be used to estimate the spectrum. Second and most importantly, we show how the MVDR method can be used to estimate the magnitude squared coherence function, which is very useful in so many applications but so few methods exist to estimate it. Simulations show that our algorithm gives much more reliable results than the one based on the popular Welch's method. View full abstract»

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  • Wavelet transform-based interferometric SAR coherence estimator

    Publication Year: 2005 , Page(s): 831 - 834
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (808 KB) |  | HTML iconHTML  

    A novel method to estimate interferometric coherence in synthetic aperture radar interferometry is proposed. It is demonstrated that this approach is not affected by the terrain topography, contrary to multilook techniques. In addition, since the method is based on the two-dimensional discrete wavelet packet transform, it allows recovering coherence information with a high spatial resolution. Results derived from simulated and experimental ESAR-DLR X- and L-band interferograms corroborate the performance of the proposed technique. View full abstract»

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  • Zero-pinning the Bernstein polynomial: a simple design technique for orthonormal wavelets

    Publication Year: 2005 , Page(s): 835 - 838
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB) |  | HTML iconHTML  

    A novel technique is presented for designing finite impulse response orthonormal wavelet filters. The filters are obtained from the spectral factorization of an appropriately designed parametric Bernstein polynomial. We show that by strategically "pinning" some of the zeros of the polynomial, the nonnegativity requirement on the polynomial, which is mandatory for orthonormal filter design, can be easily achieved. Filters with a high number of vanishing moments and sharper frequency response (but lower vanishing moments) than the maximally flat Daubechies filters can be easily designed. The technique is simple as it only involves solving linear equations yet is versatile as filters with different characteristics can be obtained with ease. View full abstract»

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  • Fast image and video denoising via nonlocal means of similar neighborhoods

    Publication Year: 2005 , Page(s): 839 - 842
    Cited by:  Papers (166)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1248 KB) |  | HTML iconHTML  

    In this letter, improvements to the nonlocal means image denoising method introduced by Buades et al. are presented. The original nonlocal means method replaces a noisy pixel by the weighted average of pixels with related surrounding neighborhoods. While producing state-of-the-art denoising results, this method is computationally impractical. In order to accelerate the algorithm, we introduce filters that eliminate unrelated neighborhoods from the weighted average. These filters are based on local average gray values and gradients, preclassifying neighborhoods and thereby reducing the original quadratic complexity to a linear one and reducing the influence of less-related areas in the denoising of a given pixel. We present the underlying framework and experimental results for gray level and color images as well as for video. View full abstract»

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  • MLC: a novel image coder based on multitree local cosine dictionaries

    Publication Year: 2005 , Page(s): 843 - 846
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4264 KB)  

    We build a multitree dictionary of local cosine bases and develop a novel image coder that extracts the best basis in such a dictionary with respect to a rate-distortion cost. This dictionary is much larger than standard quadtree-based dictionaries, and therefore, our algorithm needs more overhead bits to encode the basis selection. Despite this, we show that the resulting algorithm outperforms an existing quadtree local cosine image compression algorithm. We also show that our multitree local cosine coder outperforms both SPIHT and a multitree block-DCT method previously developed by us, on several textured images. View full abstract»

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  • Frequency-domain methods for demosaicking of Bayer-sampled color images

    Publication Year: 2005 , Page(s): 847 - 850
    Cited by:  Papers (44)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB) |  | HTML iconHTML  

    This letter presents a new and simplified derivation of the frequency-domain representation of color images sampled with the Bayer color filter array. Two new demosaicking algorithms based on the frequency-domain representation are described and shown to give excellent results. View full abstract»

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  • Mean-square performance of data-reusing adaptive algorithms

    Publication Year: 2005 , Page(s): 851 - 854
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB) |  | HTML iconHTML  

    This letter provides a unified mean-square performance analysis of the class of data reusing adaptive algorithms. The derivation relies on energy conservation arguments, and it does not restrict the regression data to being Gaussian. Simulation results show that there is a relatively good match between theory and practice. View full abstract»

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  • Cramer-Rao lower bound for parameter estimation in nonlinear systems

    Publication Year: 2005 , Page(s): 855 - 858
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB) |  | HTML iconHTML  

    Calculation of the Cramer-Rao lower bound, i.e., the inverse of the Fisher information matrix, for output data sets of a general nonlinear system is a challenging problem and is considered in this letter. It is shown that the Fisher information matrix for a data set generated by a nonlinear system with additive Gaussian measurement noise can be expressed in terms of the outputs of its derivative system that is also a nonlinear system. An example is considered arising from surface plasmon resonance experiments to determine the dynamic parameters of molecular interactions. View full abstract»

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  • A new minor component analysis method based on Douglas-Kung-Amari minor subspace analysis method

    Publication Year: 2005 , Page(s): 859 - 862
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    This letter presents a new minor component analysis algorithm that is based on the transformation of the known minor subspace analysis algorithm. The minor subspace analysis method that is adopted is the one proposed by Douglas, Kung, and Amari. The proposed minor component analysis algorithm extracts N minor components of the K-dimensional vector stationary random process N View full abstract»

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  • Online adaptive blind deconvolution based on third-order moments

    Publication Year: 2005 , Page(s): 863 - 866
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB) |  | HTML iconHTML  

    Traditional methods for online adaptive blind deconvolution using higher order statistics are often based on even-order moments, due to the fact that the systems considered commonly feature symmetric source signals (i.e., signals having a symmetric probability density function). However, asymmetric source signals facilitate blind deconvolution based on odd-order moments. In this letter, we show that third-order moments give the benefits of faster convergence of algorithms and increased robustness to additive Gaussian noise. The convergence rates for two algorithms based on third- and fourth-order moments, respectively, are compared for a simulated ultra-wideband communication channel. View full abstract»

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  • A quantitative assessment of the importance of tone in mandarin speech recognition

    Publication Year: 2005 , Page(s): 867 - 870
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB) |  | HTML iconHTML  

    How important is tone to Mandarin speech recognition? Because contextual information can resolve some lexical ambiguities, the question has been raised as to whether a strong language model obviates the need for explicit tone modeling. This letter addresses that question by evaluating the effect of tone information on word perplexity under different conditions, including knowledge of the correct tone sequence, perfect acoustic information, and imperfect syllable and tone information. Results show that conditioning on tone information can reduce word uncertainty in conversational speech by 11%-20%, depending on the accuracy of syllable and tone recognition. View full abstract»

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  • Bayesian fusion of confidence measures for speech recognition

    Publication Year: 2005 , Page(s): 871 - 874
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB) |  | HTML iconHTML  

    The application of Bayesian fusion of confidence measures to speech recognition is proposed. Feature level, decision level, and hybrid fusion are considered under the Bayesian framework. The use of speaker-adapted feature-level Bayesian fusion reduced the error rate by 19.4% as compared to the conventional single feature-based confidence scoring in an isolated word out-of-vocabulary rejection test. The decision-level Bayesian fusion also showed better performance than the majority rule. Finally, hybrid Bayesian fusion, which can combine both confidence measure features and local decisions, achieved the best performance. View full abstract»

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  • Correction to "Nonstationary Noise Estimation Using Low-Frequency Regions for Spectral Subtraction"

    Publication Year: 2005 , Page(s): 875
    Cited by:  Papers (1)
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  • List of reviewers

    Publication Year: 2005 , Page(s): 876 - 883
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  • IEEE Signal Processing Letters Information for authors

    Publication Year: 2005 , Page(s): 884 - 885
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  • 2005 Index

    Publication Year: 2005 , Page(s): 886 - 908
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  • IEEE Signal Processing Society Information

    Publication Year: 2005 , Page(s): c3
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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