Proceedings of IEEE-SP International Symposium on Time- Frequency and Time-Scale Analysis

25-28 Oct. 1994

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Displaying Results 1 - 25 of 165
  • Wigner distribution and continuous wavelet transforms for image analysis: relationships and interpretation

    Publication Year: 1994, Page(s):314 - 317
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (334 KB)

    In this paper we discuss the relationships between space-scale, and space-frequency representations for 2D images. We compare the interpretation of the two representations and show that the affine smoothed Wigner distribution class may also be advantageously used in image processing.<> View full abstract»

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  • Non stationary signals classification using time-frequency distributions

    Publication Year: 1994, Page(s):233 - 236
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (313 KB)

    The paper deals with a comparison between different non-parametric classification methods of non stationary signals. The first ones, consider the time frequency representation (TFR) of the signal as the code itself and the decision is taken following the value of a dissimilarity index between the TFRs. In the other methods, the authors compute the instantaneous log-deviation between the (positive)... View full abstract»

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  • The why and how of time-frequency reassignment

    Publication Year: 1994, Page(s):197 - 200
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (400 KB)

    A general methodology providing a better readability of any bilinear distribution has been proposed. This methodology, referred to as reassignment, is essentially a generalization of an improvement of the spectrogram proposed by Kodera, Gendrin and de Villedary (1978). After a presentation of this original work, its generalization to a wide range of distributions is shown. The close connections of... View full abstract»

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  • Detection of stop consonants with the wavelet transform

    Publication Year: 1994, Page(s):612 - 615
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (331 KB)

    We present the burst detection of stop consonants in the French language with the wavelet transform. The system is based on the study of normalized correlation functions between the modulus of the impulse wavelet transform and the same transform of the speech signal. Every correlation function presents a minimum before each maximum, where that maximum is synchronous with the burst. Two signals S/s... View full abstract»

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  • Geometry of affine distributions

    Publication Year: 1994, Page(s):80 - 83
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (319 KB)

    Bilinear affine distributions are considered from the point of view of their geometry in the time-frequency plane. General construction rules are established for interference terms, with further interpretations in terms of localization properties and generalized means. In the case of frequency modulated signals, it is shown how the pointwise application of these rules can be refined by the study o... View full abstract»

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  • Time-frequency based distance and divergence measures

    Publication Year: 1994, Page(s):64 - 67
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (330 KB)

    A study of the phase and amplitude sensitivity of the Renyi (1961) time-frequency information measure leads to the introduction of a new "Jensen-like" divergence measure. While this quantity promises to be a useful indicator of the distance between two time-frequency distributions, it is limited to the analysis of positive definite TFDs. In spite of this rather severe limitation, this measure coul... View full abstract»

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  • Proceedings of IEEE-SP International Symposium on Time- Frequency and Time-Scale Analysis

    Publication Year: 1994
    Request permission for commercial reuse | |PDF file iconPDF (20 KB)
    Freely Available from IEEE
  • Phase space localization operators: asymptotics of singular values

    Publication Year: 1994, Page(s):194 - 196
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (196 KB)

    The Weyl correspondence is a convenient and practical way to define a broad class of time-frequency localization operators. Given a region Ω in the time-frequency (or phase) plane R2 , and a distribution P(ξ, x) in the Cohen's (1989) class, the Weyl correspondence defines an operator LΩP on L2(R) which essentially localiz... View full abstract»

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  • A fast wavelet algorithm on the interval

    Publication Year: 1994, Page(s):287 - 289
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (156 KB)

    The Franklin system is an orthonormal basis of L2[0,1]. The authors give a multiresolution analysis of L2[0,1] using the Faber-Schauder system. Exact reconstruction is now allowed; the authors perform a comparison with the Stromberg system (on [0,1]) where an edge error appears when the reconstruction is made. They derive a fast algorithm which enables one to analyze and synt... View full abstract»

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  • Positive time-scale distributions

    Publication Year: 1994, Page(s):201 - 204
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (272 KB)

    We define the class of positive time-scale distributions (TSDs), and give a general method for constructing such functions. We explore various properties and moments of these distributions. Examples, of both synthetic and real signals, are given View full abstract»

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  • Robust knot detection and spline approximation using wavelet transform extrema and multi-target tracking

    Publication Year: 1994, Page(s):290 - 293
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (268 KB)

    Mallat and Hwang (1992) and Mallat and Zhong (1992) describe a novel algorithm both for signal compression and noise removal based on the extraction of the extrema of continuous wavelet transforms (CWTs) at a dyadic sequence of scales, the chaining of the extrema across scale that come from the same feature in the original signal, and the separation of noise from signal through the estimation of t... View full abstract»

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  • Study of chaotic dynamical systems via time-frequency analysis

    Publication Year: 1994, Page(s):357 - 360
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (256 KB)

    Time-frequency representation is helpful in studying the frequency pattern of nonlinear dynamical systems. Specifically, the Wigner-Gabor-Qian (WGQ) spectrogram, a synthesis of the Wigner distribution and the Gabor expansion through time-frequency distribution series, is a very useful tool because it achieves a good solution in time-frequency representation as well as few cross-interferences. The ... View full abstract»

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  • Astronomical image coding using an edge and texture model

    Publication Year: 1994, Page(s):148 - 151
    Cited by:  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (384 KB)

    Presents an image coding model that separates edge information from texture information. Edges are detected by means of a wavelet transform modulus. An image approximation is reconstructed from edges selected by a threshold operation. A texture image is obtained by subtracting the reconstructed image from the original one. The texture information is decomposed using a scheme based on an orthonorma... View full abstract»

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  • Time-frequency kernel design by the two-dimensional frequency transformation method

    Publication Year: 1994, Page(s):92 - 95
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (356 KB)

    A subclass of Cohen's class of time-frequency (t-f) distributions is introduced in which t-f distribution kernels are characterized by finite extent in time and frequency and thereby referred to as finite time-frequency (FTF) kernels. FTF kernels are provided via the frequency transformation method (FTM), used in two-dimensional (2-D) filter design View full abstract»

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  • On the construction of self-similar rational models for power-law processes

    Publication Year: 1994, Page(s):440 - 443
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (316 KB)

    The rational modelling of power-law processes is equivalent to finding a linear time-invariant system described by a rational function H(s) with a power-law magnitude response. The construction of such systems is based on the notion of scale-invariance for a specific scale change formalized by the γ-homogeneity principle. The scale-invariant nature of these systems is reflected not only in t... View full abstract»

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  • Scale domain analysis of a bat sonar signal

    Publication Year: 1994, Page(s):373 - 376
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (268 KB)

    Scale domain signal analysis has been developed in response to the need to analyse Doppler-tolerant waveforms or self-similar random signals. Following Cohen's concept of scale representations, this paper introduces the concept of higher-order scale-spectra and investigates advantages and drawbacks of scale domain versus the traditional frequency domain analysis. Several scale-domain methods are a... View full abstract»

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  • Smoothed time/frequency features for vowel classification

    Publication Year: 1994, Page(s):592 - 595
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (280 KB)

    A novel signal modeling technique is described to compute smoothed time-frequency features for encoding speech information. These time-frequency features compactly and accurately model phonetic information, while accounting for the main effects of contextual variations. These segment-level features are computed such that more emphasis is given to the center of the segment and less to the end regio... View full abstract»

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  • A recursive wavelet transform analysis of earth fault currents in Petersen-coil-protected power distribution networks

    Publication Year: 1994, Page(s):162 - 165
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (264 KB)

    Earth-phase faults are the most frequent faults likely to occur in a power distribution network. In the case of Petersen-coil-protected power networks, meaningful information is contained in the transient fault signals and should be used in the protections to increase their speed and accuracy. An earth-phase fault is simulated with EMTP (ElectroMagnetic Transient Program). Then, a recursive wavele... View full abstract»

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  • Oversampled finite-discrete Gabor transforms

    Publication Year: 1994, Page(s):276 - 279
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (400 KB)

    This paper considers the construction and fast computation of non-periodic discretizations of the Gabor transform. We first derive a reasonable finite version of the continuous transform by discretizing the integrals over regular in the time-frequency domain. We next apply the novel decomposition of the Gabor transform presented by Redding and Newsam (see Proceedings of the International Conferenc... View full abstract»

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  • Design of time-frequency representations using multiform, tiltable kernels

    Publication Year: 1994, Page(s):205 - 208
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (320 KB)

    The problem addressed in this paper is that of formulating novel Cohen's class time-frequency representations (TFRs) with multiform, tiltable kernels capable of attaining a wide diversity of shapes in the ambiguity function (AF) plane, e.g., parallel strips, crosses, tilted and untilted ellipses, diamonds, hyperbolas, rectangles, etc. We derive closed form design equations for an exponential or Bu... View full abstract»

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  • Block data flow implementation of the 2-D discrete wavelet transform

    Publication Year: 1994, Page(s):294 - 297
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (316 KB)

    Implements the 2D discrete wavelet transform (DWT) for real time image processing applications. The algorithms for the 2D wavelet transform can also be viewed as subband filter banks. The authors propose a block data flow architecture (BDFA) for the 2D product separable filter which is used for the DWT. The BDFA uses block data processing and the block data flow paradigm to minimize system managem... View full abstract»

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  • Nonuniform sampling/oversampling and extensions for wavelet subspaces

    Publication Year: 1994, Page(s):385 - 388
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (324 KB)

    In this paper, we generalize existing sampling theory for wavelet subspaces, in several directions. These new schemes allow for compactly supported synthesizing and scaling functions, which was not possible before. All the problems are treated in a unified way using multirate filter banks. This offers simple and efficient implementations of the algorithms. This new possibility of having compactly ... View full abstract»

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  • Wavelet decomposition of global solar oscillations

    Publication Year: 1994, Page(s):152 - 153
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (120 KB)

    The authors have calculated the wavelet transform of so-called helio-seismological data from the IPHIR experiment onboard the Soviet Phobos spacecraft. The mother wavelet was a modified Morlet-Grossmann wavelet. The results show that the solar oscillations have a non-stationary character, with global oscillation modes being excited and damped out at apparently random times View full abstract»

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  • Adaptive RID kernels which minimize time-frequency uncertainty

    Publication Year: 1994, Page(s):96 - 99
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (400 KB)

    The reduced interference distribution (RID) satisfies many of the desirable properties of time-frequency distributions (TFDs), including reduced interference. Using simple rules, it is possible to define kernels which guarantee the RID properties. A primitive h(t) is the starting point for kernel design. Starting with this primitive h(t), one may evolve a RID which enjoys all of the desirable prop... View full abstract»

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  • A simple model for fractional non-Gaussian processes

    Publication Year: 1994, Page(s):444 - 447
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (336 KB)

    Fractionally differenced Gaussian noise processes have been found to be useful for modeling the long-term dependencies exhibited by many real processes. Non-Gaussian processes have also been observed which exhibit long-term dependencies, but simple models have been lacking. A simple model which is a generalization of the fractionally differenced Gaussian noise process is proposed. The model should... View full abstract»

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