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
  • Adaptive filtering based on wavelet decomposition

    Publication Year: 1994, Page(s):260 - 263
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    Addresses a novel, wavelet decomposition based adaptive filtering technique. The input signal is decomposed into octave-bands and the adaptive filtering is performed on those signals using a hierarchical structure. The signal error is decomposed and used in the adaptation process. Using this technique, considerable computational reduction is achieved over the full-band scheme. Simulations show tha... View full abstract»

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  • Improved time-frequency filtering using an STFT analysis-modification-synthesis method

    Publication Year: 1994, Page(s):264 - 267
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    Time-frequency representations provide a convenient method for analyzing signals whose frequency content changes with time, and specifically those signals with components that overlap in time and/or frequency. In this paper we suggest a technique for optimally concentrating components of a signal in the time-frequency plane via a particular choice of analysis window for the short-time Fourier tran... View full abstract»

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  • Time-limited signals and Gabor expansion

    Publication Year: 1994, Page(s):268 - 271
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    Gabor (1946) expansion suffers from the consequences of the zero theorem which states that all continuous functions have a zero on the unit square in the Zak space. In particular the Gaussian function routinely selected for a window in the Gaborian analysis has a zero at (1/2,1/2). As a result a zero-matching scheme between the signal and the window must be employed, which limits the class of sign... View full abstract»

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  • Joint distributions for arbitrary variables

    Publication Year: 1994, Page(s):520 - 523
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    We compare the methods of Cohen (1971) and of Baraniuk and Jones (see Proc. IEEE ICASSP-93, p.320-323, 1993) for obtaining joint distributions for arbitrary variables. We show that the two methods produce identical results for variables whose associated operators are obtained via a unitary transformation of the time and frequency operators. In addition, we generalize this result and show that all ... View full abstract»

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  • Wavelets for image compression

    Publication Year: 1994, Page(s):338 - 341
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    The wavelet transform is becoming increasingly important in image compression applications because of its flexibility in representing nonstationary signals. Current techniques use exhaustive search procedures that are computationally intensive to find the “optimal” basis (type, order, tree). In this paper, we propose some guidelines based on the statistics of the image to be coded, for... View full abstract»

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  • The computation of Weyl-Heisenberg coefficients for critically sampled and oversampled signals

    Publication Year: 1994, Page(s):272 - 275
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (212 KB)

    We present algorithms and implementations for Weyl-Heisenberg (W-H) coefficient computation of critically sampled and oversampled periodic discrete signals. In the oversampled case, both integer oversampling and fractional oversampling are investigated. Implementation results on single RISC processor of i860 and the Paragon parallel multiprocessor system are given for sampling sizes both of powers... View full abstract»

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  • Unified theory of displacement-covariant time-frequency analysis

    Publication Year: 1994, Page(s):524 - 527
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    Presents a theory of linear and quadratic time-frequency representations (TFRs) that are covariant to time-frequency displacement operators. The theory unifies important TFR classes (short-time Fourier transform, wavelet transform; Cohen's, affine, hyperbolic, and power classes), and it allows the systematic construction of new TFRs that are covariant to a given operator View full abstract»

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  • Variable block size wavelet video coding

    Publication Year: 1994, Page(s):342 - 345
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    A new and efficient video coding algorithm is described. It is based on the wavelet decomposition of video signals using orthonormal and biorthogonal filter banks. The motion compensated error images are represented by variable size blocks. To improve the coding efficiency and to minimize the border effects associated to the wavelet transform, a new quadtree based merging algorithm was developed. ... 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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  • Warped perspectives in time-frequency analysis

    Publication Year: 1994, Page(s):528 - 531
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (388 KB)

    Unitary similarity transformations furnish a simple yet powerful vehicle for generating new classes of joint distributions based on concepts different from time, frequency, and scale. These new signal representations focus on the critical characteristics of large classes of signals and, hence, prove useful for representing and processing signals that are not well matched by current techniques. In ... View full abstract»

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  • Speech signal processing using a time-frequency distribution of Cohen's class

    Publication Year: 1994, Page(s):624 - 627
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    It is well known that the standard methods for spectral estimation of speech signals, such as spectrograms, suffer from trade-offs between time and frequency resolution. These methods usually have difficulty isolating closely spaced formants and tracking rapidly changing spectral peaks and fundamental frequency (pitch). The authors use a time-frequency distribution with compound kernel function of... View full abstract»

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  • Compound wavelets: wavelets for speech recognition

    Publication Year: 1994, Page(s):600 - 603
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    Describes a method for generating a wavelet set that requires a specific time-bandwidth product. This allows independent control of the time resolution and the number of wavelets per time sample of the sampled continuous wavelet transform to accurately parameterise speech for speech recognition. The proposed method increases the bandwidth of a wavelet without significantly affecting the time domai... View full abstract»

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  • Time-frequency analysis and observation synthesis of non-radial oscillations of white dwarfs

    Publication Year: 1994, Page(s):349 - 352
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB)

    We reconstruct temporal spectra obtained from incomplete light-curve records of white dwarfs. The regularization of the corresponding inverse problem refers to band-limited interpolation and matching pursuit. A crucial point is the choice of the frequency support of the deconvolution. We show that matching pursuit, used as a complement to Fourier analysis, is a powerful tool for discriminating the... View full abstract»

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  • Oversampling in Gabor's signal expansion by an integer factor

    Publication Year: 1994, Page(s):280 - 283
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    Gabor's (1946) expansion of a signal into a discrete set of shifted and modulated versions of an elementary signal is reviewed and its relation to sampling of the sliding-window spectrum is shown. It is indicated how Gabor's expansion coefficients can be found as samples of the sliding-window spectrum, where the window function, which still has to be determined, is related to the elementary signal... View full abstract»

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  • Application of wavelet transforms to ultrasonic NDE and remote-sensing signal analysis

    Publication Year: 1994, Page(s):472 - 475
    Cited by:  Papers (7)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    The use of discrete wavelet transforms and the discrete Gabor transforms in the ultrasonic NDE (nondestructive evaluation) and remote-sensing signal characterization and/or classification is considered. Both the NDE and the remote-sensing signals are likely to have multiple components which may be quite suitable for wavelet analysis. For the ultrasonic NDE signals, both the hidden geometrical defe... View full abstract»

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  • Discrete Cohen's class of distributions

    Publication Year: 1994, Page(s):532 - 535
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    An alias-free discrete-Cohen's class of distributions for finite discrete signals is defined. Based on this definition, the authors derive desirable distribution properties and the corresponding kernel constraints that show strong similarity with the continuous case. They also present: (a) transformations of kernels to different domains; (b) sampling schemes for discretizing continuous kernels; an... View full abstract»

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  • Nonstationary waveform analysis and synthesis using generalized harmonic analysis

    Publication Year: 1994, Page(s):429 - 432
    Cited by:  Papers (6)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    This article presents a new method of spectrum analysis for nonstationary signals, the generalized harmonic analysis (GHA) method. The short-time Fourier transform suffers from truncation effects in spectrum analysis; however, GHA using almost-periodic functions can analyze and synthesize signals without the truncation effects. We have applied GHA to nonstationary signals, such as a piano tone and... View full abstract»

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  • Near-best basis selection algorithms with non-additive information cost functions

    Publication Year: 1994, Page(s):13 - 16
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB)

    Search algorithms for finding signal decompositions called near-best bases using decision criteria called non-additive information costs are proposed for selecting bases in wavelet packet transforms. These new methods are compared with the best bases and additive information costs of Coifman and Wickerhauser (see IEEE Trans. Information Theory, vol.38, p.713-18, 1992). All near-best and best bases... View full abstract»

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