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
  • Signal waveform restoration by wavelet denoising

    Publication Year: 1996, Page(s):89 - 92
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (252 KB)

    In this paper, we first establish an approximated sampling theorem for an arbitrary continuous signal which is essential for wavelet analysis. The differences and similarities between quadrature mirror filter decomposition and wavelet decomposition are contrasted. We then propose an efficient way to recover a source signal buried in white noise by using wavelet denoising. The method is capable of ... View full abstract»

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  • Reconstruction of missing speech frames using sub-band excitation

    Publication Year: 1996, Page(s):277 - 280
    Cited by:  Papers (11)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (336 KB)

    A new reconstruction method for frame erasures in speech transmission is presented which is based on parameterization of the speech signal by means of linear prediction (LPC) and voicing analysis. The problem of generating partially voiced substitute speech signals is solved by performing separate voicing decisions in sub-bands. The method yields considerable improvements compared with silence sub... View full abstract»

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  • Diagonalization of the auto-correlation functions of random signals in terms of Cauchy wavelets using operator algebra

    Publication Year: 1996, Page(s):85 - 88
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (296 KB)

    The eigenfunction system of a kind of operator is identical to the over-complete Cauchy wavelet system, as has been shown previously. In this presentation, the re-ordering problem among this operator and its adjoint is investigated. Then, an application of this re-ordering problem to the pseudo-diagonalization problem of the autocorrelation function of a stochastic process is proposed 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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  • Pseudo-periodic 1/f-like noise

    Publication Year: 1996, Page(s):121 - 124
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (300 KB)

    This paper presents a new model for the synthesis of pseudo-periodic signals, based on self-similar noise processes that can be generated by computing the inverse multiplexed wavelet transform (MWT) of seed and characteristic sequences. These processes, which exhibit an approximate 1/f behavior near the harmonics of the fundamental frequency, are shown to be samples of a self-similar random field.... View full abstract»

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  • Wavelet filter design for image compression

    Publication Year: 1996, Page(s):273 - 276
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (248 KB)

    A new approach to wavelet filters optimized for image compression is proposed. Since the dyadic wavelet transform corresponds to convolutions of a signal with a high-pass and a low-pass filter in the time domain, it is useful to design the filters in the time domain aiming at a high energy compaction. The design technique introduced is based on a signal decomposition into suitable base functions. ... View full abstract»

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  • Analysing heart murmurs using time-frequency methods

    Publication Year: 1996, Page(s):385 - 388
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (848 KB)

    Discusses the use of time-frequency methods in the detection and analysis of heart murmurs in Phono-CardioGraphic (PCG) signals. These heart sounds can yield important diagnostic information and are measured in a non-invasive fashion. The methods employed are developed heuristically based on a model of heart sounds, but their connection to existing techniques is also presented. The method exploits... View full abstract»

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  • Optimal reduced-rank time-frequency/time-scale quadratic detectors

    Publication Year: 1996, Page(s):209 - 212
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (408 KB)

    Optimal detectors based on time-frequency/time-scale representations (TFRs/TSRs) admit a representation in terms of a bank of spectrograms/scalograms that yields a large class of detectors. These range from the conventional matched filter to the more complex higher-rank detectors offering a superior performance in a wider variety of detection situations. In this paper, we optimize this complexity ... View full abstract»

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  • Real-time prototype for microcracks detection on ceramic materials

    Publication Year: 1996, Page(s):469 - 472
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (260 KB)

    The control of quality in industrial plants is an emerging field for signal processing applications. Among the numerous techniques utilised for detecting defects in materials are ultrasonics. We present a real-time prototype for the detection of microcracks in tiles of wet ceramic by means of ultrasonics. This non-destructive evaluation needs processing of the ultrasonic signals due to noise assoc... View full abstract»

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  • An iterated rational filter bank for audio coding

    Publication Year: 1996, Page(s):81 - 84
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (336 KB)

    This paper proposes a regular third-of-an-octave filter bank for high fidelity audio coding. The originality here is twofold: first, the filter bank is an iterated orthonormal rational filter bank for which the generating filters have been designed so that its outputs closely approximate a wavelet transform. This is different from the known coding algorithms which all use an integer filter bank, a... View full abstract»

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  • Power class time-frequency representations: interference geometry, smoothing, and implementation

    Publication Year: 1996, Page(s):193 - 196
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (516 KB)

    The nth power class (PCn) of quadratic time-frequency representations (QTFRs) is specifically suited for the multiresolution analysis of signals passing through systems whose dispersion characteristic is approximately fκ. This paper considers several aspects of PC analysis important in applications. We discuss the geometry of PC auto terms and cross terms, and we propos... View full abstract»

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