Pub Date : 1992-10-04DOI: 10.1109/TFTSA.1992.274224
H. Krim, K. Drouiche, J. Pesquet
A statistical method for detecting and/or localizing nonstationarities in a process observed over a time interval T is presented. Stationarity is induced by taking a wavelet transform of the process. A parametric model is fitted to the result. The error incurred in fitting the model is shown to preserve the singularity manifested in the transform. The error is then used to establish a statistical detection test that is free of any prior knowledge about the class of signals being analyzed, and of any user input.<>
{"title":"Multiscale detection of nonstationary signals","authors":"H. Krim, K. Drouiche, J. Pesquet","doi":"10.1109/TFTSA.1992.274224","DOIUrl":"https://doi.org/10.1109/TFTSA.1992.274224","url":null,"abstract":"A statistical method for detecting and/or localizing nonstationarities in a process observed over a time interval T is presented. Stationarity is induced by taking a wavelet transform of the process. A parametric model is fitted to the result. The error incurred in fitting the model is shown to preserve the singularity manifested in the transform. The error is then used to establish a statistical detection test that is free of any prior knowledge about the class of signals being analyzed, and of any user input.<<ETX>>","PeriodicalId":105228,"journal":{"name":"[1992] Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125956127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-04DOI: 10.1109/TFTSA.1992.274122
Y.M. Zhu, Y. Gao, R. Goutte
The generic issue of texture discrimination using spectral methods is addressed. A computational method based on exploiting local spectral information of the image is presented. The method is based on the use of a two-dimensional Wigner distribution which allows a precise tracking in space of the frequency characteristics of an image. Performance is illustrated for a synthesized image and for natural textures. Potential applications are discussed.<>
{"title":"An investigation of the Wigner model for texture discrimination","authors":"Y.M. Zhu, Y. Gao, R. Goutte","doi":"10.1109/TFTSA.1992.274122","DOIUrl":"https://doi.org/10.1109/TFTSA.1992.274122","url":null,"abstract":"The generic issue of texture discrimination using spectral methods is addressed. A computational method based on exploiting local spectral information of the image is presented. The method is based on the use of a two-dimensional Wigner distribution which allows a precise tracking in space of the frequency characteristics of an image. Performance is illustrated for a synthesized image and for natural textures. Potential applications are discussed.<<ETX>>","PeriodicalId":105228,"journal":{"name":"[1992] Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis","volume":"566 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116244198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-04DOI: 10.1109/TFTSA.1992.274215
K. Nayebi, I. Sodagar, T. Barnwell
Time-varying filter banks and wavelets are studied, and a design procedure is presented. In the resulting analysis-synthesis structures, the analysis filters and the corresponding synthesis filters change with time. Equivalently, these structures can be considered as time-frequency transforms with a corresponding time-varying tiling of the time-frequency plane and with corresponding time-varying basis functions. This formulation is based on the time domain analysis of the time-varying analysis-synthesis structures. The design procedure can be used to design time-varying perfectly invertible transformations with a finite number of distinct analysis structures.<>
{"title":"The wavelet transform and time-varying tiling of the time-frequency plane","authors":"K. Nayebi, I. Sodagar, T. Barnwell","doi":"10.1109/TFTSA.1992.274215","DOIUrl":"https://doi.org/10.1109/TFTSA.1992.274215","url":null,"abstract":"Time-varying filter banks and wavelets are studied, and a design procedure is presented. In the resulting analysis-synthesis structures, the analysis filters and the corresponding synthesis filters change with time. Equivalently, these structures can be considered as time-frequency transforms with a corresponding time-varying tiling of the time-frequency plane and with corresponding time-varying basis functions. This formulation is based on the time domain analysis of the time-varying analysis-synthesis structures. The design procedure can be used to design time-varying perfectly invertible transformations with a finite number of distinct analysis structures.<<ETX>>","PeriodicalId":105228,"journal":{"name":"[1992] Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis","volume":"2 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120908909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-04DOI: 10.1109/TFTSA.1992.274145
L. G. Weiss, R. K. Young
A wideband spatial processor for a near-field array of spatially separated and possibly moving sensors is described. The sensors are assumed to be imaging an environment containing spatially distributed, and possibly moving, sources. The processor combines several temporal and spatial wavelet transforms to produce a high-resolution spatial image of the environment. It removes the conventional (narrowband) assumptions, so that many more environments can be imaged. Rapidly moving, near-field sources can be localized with high resolution by using this method. Adding sensors to the array to view the environment yields further improvements in resolution. Each sensor added provides an additional degree of information about the environment.<>
{"title":"Wideband nearfield array processing and wavelet transforms","authors":"L. G. Weiss, R. K. Young","doi":"10.1109/TFTSA.1992.274145","DOIUrl":"https://doi.org/10.1109/TFTSA.1992.274145","url":null,"abstract":"A wideband spatial processor for a near-field array of spatially separated and possibly moving sensors is described. The sensors are assumed to be imaging an environment containing spatially distributed, and possibly moving, sources. The processor combines several temporal and spatial wavelet transforms to produce a high-resolution spatial image of the environment. It removes the conventional (narrowband) assumptions, so that many more environments can be imaged. Rapidly moving, near-field sources can be localized with high resolution by using this method. Adding sensors to the array to view the environment yields further improvements in resolution. Each sensor added provides an additional degree of information about the environment.<<ETX>>","PeriodicalId":105228,"journal":{"name":"[1992] Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116179962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-04DOI: 10.1109/TFTSA.1992.274236
J. Benedetto, A. Teolis
A time-scale representation of (acoustic) signals, motivated by the structure of the mammalian auditory system, is presented. Drawing from the theory of irregular sampling and frames, a theoretical framework is developed in which iterative algorithms for reconstruction are constructed. Numerical examples are included which illustrate the validity of such a representation for new and effective methods of data compression and noise suppression.<>
{"title":"An auditory motivated time-scale signal representation","authors":"J. Benedetto, A. Teolis","doi":"10.1109/TFTSA.1992.274236","DOIUrl":"https://doi.org/10.1109/TFTSA.1992.274236","url":null,"abstract":"A time-scale representation of (acoustic) signals, motivated by the structure of the mammalian auditory system, is presented. Drawing from the theory of irregular sampling and frames, a theoretical framework is developed in which iterative algorithms for reconstruction are constructed. Numerical examples are included which illustrate the validity of such a representation for new and effective methods of data compression and noise suppression.<<ETX>>","PeriodicalId":105228,"journal":{"name":"[1992] Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis","volume":"895 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132422582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-04DOI: 10.1109/TFTSA.1992.274243
P. Tyack, W. J. Williams, G. Cunningham
Data indicating that whistles of bottlenosed dolphins Tursiops truncatus are not simple tonal signals are presented. Whistles are not simply sinsoidal signals with rather slowly varying frequency contours, but also include more complex attributes, which may be related to a short-duration phenomenon, perhaps akin to a rapid frequency modulation of the basic tonal components. These subtle fluctuations are not revealed by spectrogram analysis. It is shown that methods of time-frequency analysis such as the reduced interference distribution (RID) reveal both the tonal structure and the more subtle modulation structure.<>
{"title":"Time-frequency fine structure of dolphin whistles","authors":"P. Tyack, W. J. Williams, G. Cunningham","doi":"10.1109/TFTSA.1992.274243","DOIUrl":"https://doi.org/10.1109/TFTSA.1992.274243","url":null,"abstract":"Data indicating that whistles of bottlenosed dolphins Tursiops truncatus are not simple tonal signals are presented. Whistles are not simply sinsoidal signals with rather slowly varying frequency contours, but also include more complex attributes, which may be related to a short-duration phenomenon, perhaps akin to a rapid frequency modulation of the basic tonal components. These subtle fluctuations are not revealed by spectrogram analysis. It is shown that methods of time-frequency analysis such as the reduced interference distribution (RID) reveal both the tonal structure and the more subtle modulation structure.<<ETX>>","PeriodicalId":105228,"journal":{"name":"[1992] Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis","volume":"273 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134262390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-04DOI: 10.1109/TFTSA.1992.274228
G. Jones, B. Boashash
Aspects of generating spectrograms which may be used in the preliminary steps of time-frequency analysis are discussed. It is shown that the major problem with the application of the spectrogram is its nonunique nature, i.e., the use of an arbitrary window for analysis. The concept of window matching is introduced, whereby the selection of the window used for analysis depends on the instantaneous signal characteristics at the given time-frequency point under analysis. Generalized instantaneous parameters are derived and subsequently used to demonstrate how the window matching may be applied. An adaptive window-matched spectrogram is generated. Practical data results are given.<>
{"title":"Window matching in the time-frequency plane and the adaptive spectrogram","authors":"G. Jones, B. Boashash","doi":"10.1109/TFTSA.1992.274228","DOIUrl":"https://doi.org/10.1109/TFTSA.1992.274228","url":null,"abstract":"Aspects of generating spectrograms which may be used in the preliminary steps of time-frequency analysis are discussed. It is shown that the major problem with the application of the spectrogram is its nonunique nature, i.e., the use of an arbitrary window for analysis. The concept of window matching is introduced, whereby the selection of the window used for analysis depends on the instantaneous signal characteristics at the given time-frequency point under analysis. Generalized instantaneous parameters are derived and subsequently used to demonstrate how the window matching may be applied. An adaptive window-matched spectrogram is generated. Practical data results are given.<<ETX>>","PeriodicalId":105228,"journal":{"name":"[1992] Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134265754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-04DOI: 10.1109/TFTSA.1992.274204
Y. C. Pati, P. Krishnaprasad
Frame decompositions of the Hardy space H/sup 2/( Pi /sup +/) are investigated as a means of constructing rational approximations to a class of nonrational transfer functions. The frames of interest are generated via dilations and translations of a single real-rational analyzing wavelet. The compactness of the time-frequency localized representation is exploited in constructing low-order rational approximants.<>
{"title":"Rational wavelet decompositions and finite-dimensional approximations of a class of infinite-dimensional systems","authors":"Y. C. Pati, P. Krishnaprasad","doi":"10.1109/TFTSA.1992.274204","DOIUrl":"https://doi.org/10.1109/TFTSA.1992.274204","url":null,"abstract":"Frame decompositions of the Hardy space H/sup 2/( Pi /sup +/) are investigated as a means of constructing rational approximations to a class of nonrational transfer functions. The frames of interest are generated via dilations and translations of a single real-rational analyzing wavelet. The compactness of the time-frequency localized representation is exploited in constructing low-order rational approximants.<<ETX>>","PeriodicalId":105228,"journal":{"name":"[1992] Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134413941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-04DOI: 10.1109/TFTSA.1992.274244
C. Herley, J. Kovačević, K. Ramchandran, M. Vetterli
Expansions which give arbitrarily orthonormal tilings of the time-frequency plane are considered. These differ from the short-time Fourier transform, wavelet transform, and wavelet packets tilings in that they change over time. It is shown how orthonormal tilings can be achieved using time-varying orthogonal tree structures, which preserve orthogonality, even across transitions. One method is based on lapped orthogonal transforms, which makes it possible to change the number of channels in the transform. A second method is based on the construction of boundary filters and gives arbitrary tilings. An algorithm is presented which for a given signal decides on the best binary segmentation and which tree split to use for each segment. It is optimal in a rate-distortion sense. The results of experiments on test signals are presented.<>
{"title":"Arbitrary orthogonal tilings of the time-frequency plane","authors":"C. Herley, J. Kovačević, K. Ramchandran, M. Vetterli","doi":"10.1109/TFTSA.1992.274244","DOIUrl":"https://doi.org/10.1109/TFTSA.1992.274244","url":null,"abstract":"Expansions which give arbitrarily orthonormal tilings of the time-frequency plane are considered. These differ from the short-time Fourier transform, wavelet transform, and wavelet packets tilings in that they change over time. It is shown how orthonormal tilings can be achieved using time-varying orthogonal tree structures, which preserve orthogonality, even across transitions. One method is based on lapped orthogonal transforms, which makes it possible to change the number of channels in the transform. A second method is based on the construction of boundary filters and gives arbitrary tilings. An algorithm is presented which for a given signal decides on the best binary segmentation and which tree split to use for each segment. It is optimal in a rate-distortion sense. The results of experiments on test signals are presented.<<ETX>>","PeriodicalId":105228,"journal":{"name":"[1992] Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis","volume":"10 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130818449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-10-04DOI: 10.1109/TFTSA.1992.274209
J. Stach, S. Shaw
A relational tree (RT) is a signal representation used to discriminate between multidimensional signals with arbitrary nonlinear monotonic distortion. The use of RTs is limited by noise. Scale-space filtering takes advantage of the inherently scale-like properties of an RT to provide a more robust signal representation across distortions. Some methods and properties of Gaussian scale-space filtering of RTs are examined. Scale trees (STs) and conventionally filtered (fixed-scale) RTs have been shown to be subsets of this process. Since the effect of scale-space filtering is to move segmentation uncertainty toward the leaves of the tree, other operations performed in the tree domain, such as filtering, can be optimized as well.<>
{"title":"Robust relational trees by scale-space filtering","authors":"J. Stach, S. Shaw","doi":"10.1109/TFTSA.1992.274209","DOIUrl":"https://doi.org/10.1109/TFTSA.1992.274209","url":null,"abstract":"A relational tree (RT) is a signal representation used to discriminate between multidimensional signals with arbitrary nonlinear monotonic distortion. The use of RTs is limited by noise. Scale-space filtering takes advantage of the inherently scale-like properties of an RT to provide a more robust signal representation across distortions. Some methods and properties of Gaussian scale-space filtering of RTs are examined. Scale trees (STs) and conventionally filtered (fixed-scale) RTs have been shown to be subsets of this process. Since the effect of scale-space filtering is to move segmentation uncertainty toward the leaves of the tree, other operations performed in the tree domain, such as filtering, can be optimized as well.<<ETX>>","PeriodicalId":105228,"journal":{"name":"[1992] Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114867220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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