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Time-Frequency and Time-Scale Analysis, 1998. Proceedings of the IEEE-SP International Symposium on

Date 9-9 Oct. 1998

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  • Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)

    Publication Year: 1998
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    Freely Available from IEEE
  • Author index

    Publication Year: 1998, Page(s):xii - xiv
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    Freely Available from IEEE
  • Time-frequency distributions of subdural EEG at epileptic seizure onset

    Publication Year: 1998, Page(s):73 - 76
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (440 KB)

    A high-frequency signal occurring at epileptic seizure onset is investigated using time-frequency methods. This signal is extracted from the background activity by repeated forward and inverse Gabor transformations. The generation sites of this signal are determined by displaying the average signal power values with a 3-D anatomical image obtained from MRI scans View full abstract»

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  • Estimating neural sources from each time-frequency component of magnetoencephalographic data

    Publication Year: 1998, Page(s):69 - 72
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    We have developed a method that incorporates the time-frequency characteristics of neural sources into magnetoencephalographic (MEG) source estimation. This method calculates a time-frequency matrix in which diagonal and off-diagonal terms are the auto- and cross-time-frequency distributions of multi-channel MEG recordings, respectively. The method averages this matrix over the time-frequency regi... View full abstract»

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  • Wavelet transform-based strain estimator for medical imaging

    Publication Year: 1998, Page(s):65 - 68
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    A new signal processing algorithm based on a wavelet transform (WT) is proposed for instantaneous strain estimation in acoustic elastography, where the interior elasticity distribution of a biological tissue is imaged. The proposed estimator weights ultrasonic echo signals acquired before tissue compression by a Gaussian window function and uses the resulting waveform as a mother wavelet to calcul... View full abstract»

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  • Two-dimensional nonseparable multiwavelet transform and its application

    Publication Year: 1998, Page(s):61 - 64
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    Two-dimensional compactly supported, orthogonal non-separable multiwavelets and filter-banks are presented. We investigate the general subset of multiwavelets with a corresponding polyphase matrix that can be factored as a product of degree-1 factors in one variable. We consider in particular multiwavelets with vanishing moments. The number of vanishing moments that can be achieved increases with ... View full abstract»

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  • On modeling of self-similar random processes in discrete-time

    Publication Year: 1998, Page(s):333 - 336
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (436 KB)

    Novel models of stochastic self-similar processes in the discrete-time domain are presented. The results developed are based on the definition of a discrete-time scaling (dilation) operation through a mapping between the discrete and continuous frequencies. It is shown that it is possible to have continuous scaling factors through this operation even though the signal itself is discrete. White noi... View full abstract»

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  • Spatio-temporal continuous wavelets for the analysis of motion on manifolds

    Publication Year: 1998, Page(s):57 - 60
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    This paper presents kinematical Lie algebras and Lie groups that describe motion on differentiable spatiotemporal manifolds. Motion is assumed to be translational and rotational with position, velocity and acceleration. The general kinematical groups that are derived have action that depends up the local chart and the local curvature. Squared integrable representations of these Lie groups define c... View full abstract»

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  • Comparative analysis of the performance of the time-frequency distributions with knee joint vibroarthrographic signals

    Publication Year: 1998, Page(s):273 - 276
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB)

    Vibroarthrographic (VAG) signals emitted by human knee joints can be used to develop a non-invasive diagnostic tool to detect articular cartilage degeneration. VAG signals are nonstationary and multicomponent in nature; time-frequency distributions (TFDs) provide powerful means to analyze such signals. The objective of this paper is to determine the TFD suitable for identification and extraction o... View full abstract»

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  • The slantlet transform

    Publication Year: 1998, Page(s):53 - 56
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    The discrete wavelet transform (DWT) is usually carried out by filter bank iteration, however, for a fixed number of zero moments, this does not yield a discrete-time basis that is optimal with respect to time-localization. This paper discusses the implementation and properties of an orthogonal DWT, with two zero moments and with improved time-localization. The basis is not based on filter bank it... View full abstract»

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  • Signal synthesis and positive time frequency distributions

    Publication Year: 1998, Page(s):17 - 20
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    A method for obtaining a generalized transfer function (GTF) of a linear time-varying system based on the evolutionary spectral theory is proposed. This GTF can be used to synthesize the signal, and its magnitude squared function results in the signal's positive time frequency distribution that satisfies the marginals (i.e., a Cohen-Posch (1995) TFD). The procedure allows any prior estimate of the... View full abstract»

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  • Adaptive time-frequency distributions via the shift-invariant wavelet packet decomposition

    Publication Year: 1998, Page(s):645 - 648
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    Utilizing the shift-invariant wavelet packet decomposition (SIWPD), various useful properties relevant to time-frequency analysis, including high energy concentration and suppressed interference terms, can be achieved simultaneously in the Wigner domain. A prescribed signal is expanded on its best basis and transformed into the Wigner domain. Subsequently, the interference terms are eliminated by ... View full abstract»

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  • Performance analysis of the DS/SS communications receiver implementing a short time Fourier transform interference excision system

    Publication Year: 1998, Page(s):393 - 396
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    The short-time Fourier transform (STFT) is employed for nonstationary jammer excision in direct sequence spread spectrum (DS/SS) communication systems. The received signal is first analyzed by the STFT. The localized interferers in the time-frequency (t-f) domain are then removed by binary excisions. Finally, the synthesized signal is correlated with the PN sequence and passed to the detector. The... View full abstract»

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  • Lifting construction of non-linear wavelet transforms

    Publication Year: 1998, Page(s):49 - 52
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (516 KB)

    This paper analyzes non-linear wavelet transforms using the lifting construction. The lifting construction exploits a spatial-domain, prediction-error interpretation of the wavelet transform and provides a powerful framework for designing customized transforms. We use the lifting construction to better understand the performance of wavelet transforms that utilize median and Volterra filters View full abstract»

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  • A multifractal wavelet model for positive processes

    Publication Year: 1998, Page(s):341 - 344
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    In this paper, we describe a new multiscale model for characterizing positive-valued and long-range dependent data. The model uses the Haar wavelet transform and puts a constraint on the wavelet coefficients to guarantee positivity, which results in a swift O(N) algorithm to synthesize N-point data sets. We elucidate our model's ability to capture the covariance structure of real data, study its m... View full abstract»

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  • Invertible time-frequency surfaces

    Publication Year: 1998, Page(s):13 - 16
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    A classical problem in time-frequency (TF) analysis is the inversion of a TF surface to recover a signal whose TF representation is that surface. A class of invertible surfaces is presented. In this class, simple processes may be used to recover the signal and “spectrum” directly from the surface. These surfaces are linear generalizations of one-dimensional linear transforms, and may b... View full abstract»

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  • Wavelet-based empirical Wiener filtering

    Publication Year: 1998, Page(s):641 - 644
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (380 KB)

    Existing denoising schemes rarely use multiple-bases representations and if they do, they do not address the choice of the different bases. We present a new denoising scheme based on multiple bases processing. The multiple bases used in the denoising algorithm are generated via unitary transforms. These unitary transforms also allow the construction of new wavelet bases. In the new domains spanned... View full abstract»

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  • Interference-resistant detection based on time-frequency subspaces

    Publication Year: 1998, Page(s):389 - 392
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    The difficulty of modeling interference is one of the main problems in constructing an efficient interference-resistant detector. We present a new detector which exploits the signal correlation structure to account for interference. In order to make a decision between two composite hypotheses, our detector uses the generalized likelihood ratio test. Preliminary results suggest that the resulting d... View full abstract»

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  • A nonuniform, shift-invariant, and optimal algorithm for Malvar's wavelet decomposition

    Publication Year: 1998, Page(s):45 - 48
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    In this article, we propose a new decomposition scheme for Malvar's wavelet representation. Our algorithm is nonuniform, shift-invariant and minimal for an information cost function, contrary to the shift-invariant algorithm of Cohen. We propose some restrictions to our algorithm in order to reduce the complexity and permitting us to provide some partitions of the signal in agreement with its stru... View full abstract»

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  • Design of optimal lifting wavelet filters for data compression

    Publication Year: 1998, Page(s):337 - 340
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    This paper presents a new method to design wavelet filters optimized for time-series data compression. The features of these filters, called signal adapting lifting wavelet filters, are to vanish the wavelet coefficients, adapting to the input signals by tuning free parameters contained in the lifting scheme. Newly constructed filters are almost compactly supported and are perfect reconstruction f... View full abstract»

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  • On the dimension of the discrete Wigner-Ville transform range space: application to time-frequency based detectors design

    Publication Year: 1998, Page(s):5 - 8
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    The information conveyed by the discrete Wigner-Ville representations of real, complex or analytic signals is highly redundant, each time-frequency location being related to others via non-obvious relationships. In this paper, we demonstrate that there also exists a large amount of linear relationships between time-frequency samples. This implies that a whole discrete Wigner-Ville representation c... View full abstract»

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  • A channelized cross spectral method for improved frequency resolution

    Publication Year: 1998, Page(s):101 - 104
    Cited by:  Papers (2)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    A common problem in signal processing is the detection of weak tones in noise. Most tone recovery methods assume the presence of a single tone, or that the existing tones are sparse and well separated in frequency. In this paper, it is shown that tones may be detected and accurately estimated by first estimating a frequency error using the cross-spectral phase. The signal is then heterodyned by th... View full abstract»

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  • A new complexity prior for multiresolution image denoising

    Publication Year: 1998, Page(s):637 - 640
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (512 KB)

    Application of the minimum description length (MDL) principle to multiresolution image denoising has been somewhat unsuccessful to date. This disappointing performance is due to the crudeness of the underlying prior image models, which lead to overly sparse solutions. We propose a new family of complexity priors based on Rissanen's (1984, 1992) universal prior for integers, which produces estimate... View full abstract»

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  • Trained wavelets used to detect epileptic spikes

    Publication Year: 1998, Page(s):285 - 288
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    Although many authors developed different methods for automatic detection of epileptic spikes, so far a method for clinical routine has not yet evolved. Moreover the ambiguous definition of these waves makes the detection more difficult. This paper presents a new procedure to automatically detect and localise the interictal epileptic spikes based on their shape and duration. We used the discrete w... View full abstract»

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  • Modulation and warping operators in joint signal analysis

    Publication Year: 1998, Page(s):9 - 12
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (380 KB)

    We define two broad classes of unitary operator families termed modulation and warping operators. Some fundamental relations connecting these operators are shown. Application of the characteristic function method and the covariance method to modulation and warping operators yields joint (a, b), (α, β), and time-frequency signal representations that satisfy marginal and covariance proper... View full abstract»

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