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Signal Processing Letters, IEEE

Issue 12 • Date Dec. 2006

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Displaying Results 1 - 21 of 21
  • Table of contents

    Page(s): C1 - C4
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  • IEEE Signal Processing Letters publication information

    Page(s): C2
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  • Blind Near-MAP Selection Diversity With Multiuser Detection for Multiuser OFDM

    Page(s): 717 - 720
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB) |  | HTML iconHTML  

    This letter proposes a receiver algorithm for orthogonal frequency division multiplexing (OFDM) with receiver diversity that uses a new multiuser generalization of the maximum a posteriori probability (MAP) selection diversity combining followed by successive interference cancellation with least-square projection for multiuser detection. Simulation results show that the proposed approach achieves near-maximal-ratio-combining performance at a much lower complexity View full abstract»

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  • Fast Computation of Partial DFT for Comb Spectrum Evaluation

    Page(s): 721 - 724
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB) |  | HTML iconHTML  

    A comb spectrum evaluation problem arises in the channel estimation of pilot symbol-assisted modulation (PSAM) systems and also in the (de)modulation of multichannel communication system based on orthogonal frequency division multiplexing (OFDM). In this letter, we decompose an M-component comb spectrum evaluation with transform length N into 1) a fast Fourier transform evaluation of transform length M of a length M vector, 2) which in turn is obtained from the lengthN input vector (by folding and scaling). This decomposition allows for the application of split-radix and radix-4 algorithms for evaluation of M length transform and efficient computation of the length M vector from the length N input vector, which is classically termed as "pruning." When N=2p, the comb spectrum computation requires only N/8+M/3log2 M nontrivial complex multiplications, if N/Mges8. In addition, conditions under which comb spectrum evaluation can be done in O(MlogM) complex multiplies are identified View full abstract»

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  • Concerning continued fractions representation of noninteger order digital differentiators

    Page(s): 725 - 728
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (199 KB) |  | HTML iconHTML  

    The discretization of a fractional-order differentiator snu , where nu is a real number 0<nu<1, is an important issue in digital signal processing. This letter gives the analytical expression of the convergents of a continued fraction expansion of the binomial (1+s)nu to get a rapidly convergent, stable, minimum-phase approximation of digital differentiators View full abstract»

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  • Memory Extraction From Dynamic Scattering Junctions in Wave Digital Structures

    Page(s): 729 - 732
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (235 KB) |  | HTML iconHTML  

    In this letter, we show that a computable tree-like interconnection of parallel/series wave digital (WD) adaptors with memory (i.e., characterized by reflection filters instead of reflection coefficients) is equivalent to a like interconnection of standard (memoryless) adaptors whose peripheral ports are connected to mutators (two-port adaptors with memory). In proving all this, we provide a methodology for "extracting the memory" from a macro-adaptor, which can be fruitfully employed to simplify the implementation of WD structures View full abstract»

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  • On Interpolation and Resampling of Discrete Data

    Page(s): 733 - 736
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (135 KB) |  | HTML iconHTML  

    This letter introduces a new representation of discrete signals based on the mathematical notions of functionals and continuous dual spaces. A new and more general sampling theorem is also suggested. Next, the problems of interpolating and resampling discrete signals are addressed; and a general solution using functional interpolation-which is applicable to many different settings-is proposed. Families of resampling filters dubbed de Boor-Ron filters that use de Boor-Ron interpolation are introduced, and their numerical realization is discussed. Some applications of this research are suggested View full abstract»

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  • Accurate Video Alignment Using Phase Correlation

    Page(s): 737 - 740
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (201 KB) |  | HTML iconHTML  

    In this letter, we present an accurate technique for temporally aligning two video sequences of the same scene captured by nonsynchronized cameras. An iterative procedure is proposed to successively align the sequences in space and time; and the existing two-dimensional phase-correlation method is generalized into three dimensions to achieve subframe accuracy. The ground-truth of subframe temporal alignment is obtained by using supplementary audio signals sampled at a much higher rate. The accuracy of our technique is demonstrated by experimental results using real-world sequences View full abstract»

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  • Binary Image Authentication With Tampering Localization by Embedding Cryptographic Signature and Block Identifier

    Page(s): 741 - 744
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (399 KB) |  | HTML iconHTML  

    This letter proposes a novel two-layer blind binary image authentication scheme, in which the first layer is targeted at the overall authentication and the second layer is targeted at identifying the tampering locations. The "flippability" of a pixel is determined by the "connectivity-preserving" transition criterion. The image is partitioned into multiple macro-blocks that are subsequently classified into eight categories. The block identifier is defined adaptively for each class and embedded in those "qualified" and "self-detecting" macro-blocks in order to identify the tampered locations. Experimental results validate the arguments made View full abstract»

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  • Blind Equalization of Cross-QAM Signals

    Page(s): 745 - 748
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (297 KB) |  | HTML iconHTML  

    This letter presents two new blind equalization algorithms that are specifically designed for cross-QAM signals. Proposed algorithms minimize the dispersion of the equalizer output with respect to single or multiple cross-shaped zero error contour(s). Simulations and analysis demonstrate the good performance of the proposed algorithms View full abstract»

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  • Postprocessing With Wiener Filtering Technique for Reducing Residual Crosstalk in Blind Source Separation

    Page(s): 749 - 751
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (267 KB) |  | HTML iconHTML  

    In this letter, a postprocessing method using the Wiener filtering technique is proposed to reduce the residual crosstalk in frequency-domain independent component analysis (FDICA). By the proposed method, the target signal components remain with little attenuation while the interference components are suppressed. The experimental results show that the proposed method reduces the residual crosstalk and slightly improves the separation performance over the postprocessing using the normalized least-mean-square (NLMS) algorithm by about 1-2 dB with much less computation View full abstract»

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  • Moment Estimation and Dithered Quantization

    Page(s): 752 - 755
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (335 KB) |  | HTML iconHTML  

    This letter examines the influence of low-bit quantization on moment estimators with special emphasis on the 1-bit case. Moment estimators are especially useful if no prior knowledge on the distribution of the observations is available or if an ML approach is analytically intractable or computationally infeasible. In order to arrive at analytical results for this very general case, we focus on a dithered quantization scheme that allows us to specify and analyze its asymptotic behavior. We show that consistency can be retained under mild conditions, and furthermore, we quantify the asymptotic variance. Additionally, we illustrate how to find an estimator that achieves the best performance possible in this scenario. Finally, we bolster our analytical results with simulations for the illustrative case of an AR(1) process and provide a comparison with undithered schemes. A conclusion summarizes this letter's contribution and explores possible areas of application View full abstract»

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  • Computing Nonlinear \tau -Estimation Based on Dynamic Differential Evolution Strategy

    Page(s): 756 - 759
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (142 KB) |  | HTML iconHTML  

    A novel algorithm named NTDDE to compute the nonlinear tau-estimation based on the dynamic differential evolution strategy is proposed in this letter. We construct a new updating stage for this dynamic differential evolution strategy to generate a population with better performance than before. The experimental evidence has been gathered to show that the proposed algorithm is capable of computing the nonlinear tau-estimation efficiently View full abstract»

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  • Minimization of Utterance Verification Error Rate as a Constrained Optimization Problem

    Page(s): 760 - 763
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (116 KB) |  | HTML iconHTML  

    Since utterance verification (UV) may be treated as a two-class classification problem, it may be improved with discriminative training such as minimum verification error training or minimum verification error rate training. However, since in practice, one usually has to pick a specific false-acceptance or false-rejection rate for one's system, it is more desirable to optimize UV performance at a particular operating point. In this letter, we show that further improvement can be achieved by treating UV at a specific operating point as a constrained optimization problem View full abstract»

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  • List of Reviewers

    Page(s): 764 - 771
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  • IEEE Signal Processing Letters Information for authors

    Page(s): 772 - 773
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  • IEEE Transactions on Multimedia

    Page(s): 774
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  • 2007 International Conference on Multimedia & Expo (ICME)

    Page(s): 775
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  • Special issue on music information retrieval (MIR)

    Page(s): 776
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  • 2006 Index

    Page(s): 777 - 796
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  • IEEE Signal Processing Society Information

    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.

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Meet Our Editors

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