Proceedings of Third International Symposium on Time-Frequency and Time-Scale Analysis (TFTS-96)

18-21 June 1996

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  • Proceedings of Third International Symposium on Time-Frequency and Time-Scale Analysis (TFTS-96)

    Publication Year: 1996
    Request permission for commercial reuse | PDF file iconPDF (699 KB)
    Freely Available from IEEE
  • Ridges associated to continuous linear time-frequency representations of asymptotic and transient signals

    Publication Year: 1996, Page(s):177 - 180
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (393 KB)

    In most fields of experimental physics, signals to be considered possess evolutive spectral characteristics. This situation is encountered for instance when one deals with acoustic signals, from musical sounds to nondestructive evaluation (Guillemain and Kronland-Martinet, 1996). The characterization of such signals is improved if time-frequency techniques are used. The representations obtained th... View full abstract»

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  • Using Malvar wavelets for transient detection

    Publication Year: 1996, Page(s):229 - 232
    Cited by:  Papers (2)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (317 KB)

    This paper is devoted to the detection of transient acoustic signals in very low signal-to-noise ratio contexts. The proposed algorithm uses the adaptive Malvar wavelet transform. It leads to a partition of the signal which is "optimal" according to a criteria that tests the Gaussian nature of the segments. A statistic based on the kurtosis is computed from this segmentation. View full abstract»

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  • Redundancy in a frame of wavelets-based matched-filter

    Publication Year: 1996, Page(s):257 - 260
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    We propose in this paper a formulation for the matched-filter (MF) based on the frame of wavelets. We precisely compare the performance of the time-domain MF to that of this wavelet-based MF, with respect to the level of redundancy of the sampling of the time-scale plane, or equivalently, of the frame. The main result is that the redundancy of the discrete wavelet transform, instead of improving t... View full abstract»

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  • Multiresolution image reconstruction by wavelet decomposition

    Publication Year: 1996, Page(s):281 - 284
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (551 KB)

    We present a method of image reconstruction based on wavelet decomposition. The method seeks to overcome the problem of noise amplification during the image reconstruction process. We decompose the raw image to be reconstructed into several wavelet planes and a residual image, we reconstruct each one independently using an iterative maximum likelihood algorithm. To control the process, we stop the... View full abstract»

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  • Abrupt changes detection in the time-frequency plane

    Publication Year: 1996, Page(s):285 - 288
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (387 KB)

    This paper deals with a comparison between two new non-parametric methods for detecting abrupt spectral changes in non-stationary signals. The first one consists in comparing two smoothed time-frequency representations (TFRs), as well as for parametric approaches, a long-time and a short-time model are compared. In front of abrupt changes, the instantaneous distance between the two TFRs will sharp... View full abstract»

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  • High-speed moving sources analysis

    Publication Year: 1996, Page(s):397 - 400
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    This article describes the first step of moving acoustic sources analysis. Time-frequency and time-scale tools are used to characterize the signal received on a fixed microphone. It permits one to improve localisation methods. Simulations are presented in case of a sinusoidal source. An experiment with a known source fixed on a high speed train (TGV) is carried out. Then, the signal of a TGV comin... View full abstract»

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  • An efficient subband decomposition based on the Hilbert transform for high-resolution spectral estimation

    Publication Year: 1996, Page(s):409 - 412
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    This paper deals with high-resolution frequency estimation for narrow-band plane waves. We propose an approach based on subband decomposition in the spectral domain to improve the performance of high-resolution analysis. This decomposition is based on the Hilbert transform for one and two-dimensional signals. This improvement is tested on ESPRIT and MEMP techniques. We first present the subband de... View full abstract»

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  • Classification of power distribution system fault currents using wavelets associated to artificial neural networks

    Publication Year: 1996, Page(s):421 - 424
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (401 KB)

    In a power distribution system with a resonant neutral grounding, traditional protection algorithms based on a steady state analysis are no longer adapted. Hence a good use of transients becomes essential. This paper deals with the possibility of using wavelet transform as a preprocess for artificial neural networks (ANN) in the algorithm of power system relays. The ANN decides, after training, if... View full abstract»

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  • Ultrasonic crack detection and modelization by wavelet analysis

    Publication Year: 1996, Page(s):485 - 488
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (311 KB)

    Wavelet analysis has been applied as a signal processing tool for ultrasonic crack detection at an interface. The basic idea is to discriminate between signatures in the time-frequency frame, precisely in the time-scale frame. The tool is also shown to be a good one to qualify modelizations of the interaction between waves and flaws. It also allows one to reject parasitic distorted signals. View full abstract»

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  • Multiresolution analysis scheme for ERS-1 image segmentation

    Publication Year: 1996, Page(s):489 - 492
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (568 KB)

    We exploit the speckle information to provide ERS-1 images segmentation into regions, with reference to roughness. We describe a new segmentation scheme by using multi-scale information related to multifractal dimensions. We show that two different natural regions will give on radar imaging different roughness. The roughness characteristic may be considered as preliminary segmentation criterion. T... View full abstract»

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  • Instantaneous frequency tracking of a sine wave phase modulation signal

    Publication Year: 1996, Page(s):501 - 504
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    When a signal is modulated by a sine with a low index of modulation, the tracking of the instantaneous frequency encounters many difficulties. In the application of acoustic velocity measurement by means of laser Doppler anemometry, the limitations appear quite rapidly with the signal processing now available. The approaches, proposed assume a knowledge of the modulation frequency and need several... View full abstract»

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  • Supervised time-frequency reassignment

    Publication Year: 1996, Page(s):517 - 520
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (384 KB)

    The reassignment method has been proved to improve the time-frequency representation of deterministic signals and especially of "chirp-like" FM signals. Unfortunately, reassignment presents some limitations when broadband noise is present. In this case, the squeezing process yields peaked areas in noise-only regions: this drawback should be avoided, since a rather flat energy distribution should b... View full abstract»

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  • Index

    Publication Year: 1996
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    Freely Available from IEEE
  • Smooth multiwavelets based on two scaling functions

    Publication Year: 1996, Page(s):309 - 312
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    In this paper new multiwavelets based on several scaling functions are designed. The resulting wavelets exhibit the following properties: compact support, symmetry and orthogonality, arbitrary approximation order as well as good frequency resolution. The new bases are quite similar to the well known splines and also have close relationships to multirate filterbanks (multiwavelets based on one scal... View full abstract»

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  • Wigner-Ville distribution decomposition via wavelet packet transform

    Publication Year: 1996, Page(s):413 - 416
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    A new time-frequency distribution is proposed in this paper. It is based on a combination of the Wigner-Ville distribution (WVD) decomposition and the wavelet packet transform. First, the input signal is optimally decomposed into frequency bands by a best basis selection. Then, each subsignal within a frequency band is represented by the WVD decomposition. Finally, the proposed decomposition is ob... View full abstract»

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  • Analysis of inherent limitations in localizing step-like singularities in a continuous signal

    Publication Year: 1996, Page(s):21 - 24
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB)

    The Cramer-Rao lower bound (CRLB) on the estimation error of the time of arrival of a continuous waveform with step-like singularities cannot be evaluated directly. Other performance bounds result in expressions which ignore the effect of finite processing band on the achievable performance. This paper presents a close-form expression for a Cramer-Rao type bound which describes the achievable perf... View full abstract»

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  • Variable-delay dyadic wavelets

    Publication Year: 1996, Page(s):305 - 308
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    Signal processing based on the wavelet transform is a new tool for signal approximation. It finds applications in signal compression, adaptation, classification and enhancement. The overall delay in a conventional wavelet system is fixed since it depends on the symmetry point of a linear-phase halfband filter. In this paper, we introduce the theory and design of a new filter bank and wavelet syste... View full abstract»

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  • Maximum-likelihood estimation of multiscale stochastic model parameters

    Publication Year: 1996, Page(s):17 - 20
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    We consider the class of multiscale stochastic models developed by Chou, Willsky and Benveniste (see IEEE Trans. on Automatic Control, vol.39, no.3, 1994) and by Luettgen, Karl, Willsky and Tenney (see IEEE Trans. Signal Processing, vol.41, no.12, 1993) for signal and image modeling. These are Markov random field models on trees that describe signals in a scale-recursive way. In particular, they a... View full abstract»

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  • New properties for discrete, bilinear time-frequency distributions

    Publication Year: 1996, Page(s):505 - 508
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    The most straightforward discrete implementation of bilinear time-frequency distributions (TFDs) are aliased in frequency, so as a result many different discrete TFDs have been developed. The traditional viewpoint in constructing discrete TFDs is that they should be samples of continuous TFDs. This paper introduces a second viewpoint: that discrete TFDs are inherently different, and thus, while ha... View full abstract»

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  • An operator theory approach to discrete time-frequency distributions

    Publication Year: 1996, Page(s):521 - 524
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    The theoretical link between a discrete-time sequence and its discrete-time/discrete-frequency representation has heretofore been established via a uniform sampling of their continuous-time counterparts. We provide a direct link between the two which we establish using the concepts of operator theory. We see that many similarities, but also some important differences, exist between the results of ... View full abstract»

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  • Convex multiresolution analysis

    Publication Year: 1996, Page(s):301 - 304
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    A standard wavelet multiresolution analysis can be defined via a sequence of projection operators onto a monotone sequence of closed vector subspaces possessing suitable invariance properties. We propose an extension of this framework in which the linear projection operators are replaced by nonlinear retractions onto convex sets. These retractions are chosen so as to provide a recursive, monotone ... View full abstract»

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  • Orthogonal wavelets and stochastic gradient-based algorithms

    Publication Year: 1996, Page(s):405 - 408
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    Orthogonal wavelets have been used successfully to improve the convergence of the least mean squares (LMS) algorithm. This gave rise to the wavelet transform-domain LMS algorithm (WTDLMS). In this paper a fast version of this algorithm is presented. This algorithm is then applied to the problem of adaptive channel equalization View full abstract»

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  • Discrete rotational Gabor transform

    Publication Year: 1996, Page(s):169 - 172
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    In this paper, we present a discrete rotational Gabor transform and apply it to signal representation on a non-rectangular time-frequency plane tiling. We use a modified version of the recently proposed discrete rotational Fourier transform. The rotational Gabor transform decomposes a signal using as basis functions scaled, translated and modulated by linear chirps windows. As a result, the time-v... View full abstract»

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  • New method of linear time-frequency analysis for signal detection

    Publication Year: 1996, Page(s):13 - 16
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    Previous work on standard signal detection via linear time-frequency (TF) transforms has focused on detectors based on the standard linear TF transforms: the short-time Fourier transform (STFT), the Gabor transform, and the wavelet transform (WT). This paper examines two methods of improving linear-TF-based detection. The first method uses the Coifman-Meyer-Wickerhauser (see IEEE Transactions on I... View full abstract»

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