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# Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)

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Displaying Results 1 - 25 of 170
• ### Proceedings of the IEEE-SP International Symposium on Time-Frequency and Time-Scale Analysis (Cat. No.98TH8380)

Publication Year: 1998
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• ### Author index

Publication Year: 1998, Page(s):xii - xiv
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• ### Automatic classification of the temporomandibular joint sounds using scale and time-shift invariant representation of their time-frequency distributions

Publication Year: 1998, Page(s):265 - 268
Cited by:  Papers (2)
| | PDF (320 KB)

Stethoscope auscultation can ascertain the presence of abnormal temporomandibular joint (TMJ) sounds, but auscultatory findings are inherently subjective and difficult to document for accurate comparison of diagnoses among different clinicians, or within the same patient over time. Time-frequency analysis of the TMJ sounds using reduced interference distributions (RIDs) indicate that several types... View full abstract»

• ### Canonical time-frequency processing for broadband signaling over dispersive channels

Publication Year: 1998, Page(s):369 - 372
| | PDF (332 KB)

Even though broadband signaling and reception is often employed in practice for communication over time- and frequency-dispersive channels, existing receiver designs do not fully exploit the advantage of broadband signaling. We introduce a framework for time-frequency processing that is dictated by a canonical characterization of linear dispersive channels and fully utilizes the advantage of broad... View full abstract»

• ### Signal correction in magnetic resonance spectroscopy

Publication Year: 1998, Page(s):261 - 264
Cited by:  Papers (1)
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Two methods of adaptive, non-linear filtering in Fourier- and wavelet-space are presented and applied to the correction of baseline and phase distortion of magnetic resonance spectroscopic signals. Both methods consist of estimating the model parameters describing the signal and constructing a multiplicative filter based on these estimations. While the Fourier filter method can be used for baselin... View full abstract»

• ### Enhanced PN code tracking and detection using wavelet packet denoising

Publication Year: 1998, Page(s):365 - 368
Cited by:  Papers (3)
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In an effort to transmit information over communication channels that contain both Gaussian and non-Gaussian noise components, military and commercial applications frequently rely upon the use of direct sequence spread spectrum (DSSS) techniques. Whilst DSSS is an interference tolerant modulation scheme, situations may be encountered when the processing gain offered by the pseudonoise (PN) spreadi... View full abstract»

• ### Precise determination of starting time of epileptic seizures using subdural EEG and wavelet transforms

Publication Year: 1998, Page(s):257 - 260
Cited by:  Papers (2)  |  Patents (1)
| | PDF (512 KB)

Biorthogonal wavelet transforms are applied to multichannel subdural electroencephalographic data to determine the time of epileptic seizure onset. A soft-thresholding technique is utilized to separate the ictal activity using a set of threshold values computed from manually selected training segments. The time points of seizure onset are detected by a new data integration procedure View full abstract»

• ### Modulated fractional Gaussian noise: a process with non-Gaussian wavelet details

Publication Year: 1998, Page(s):361 - 364
Cited by:  Papers (2)
| | PDF (288 KB)

The aim of this article is to propose a very simple model that is able to reproduce both scaling laws and scale dependent non-Gaussian wavelet details. It is based on the modulated version of a fractional Gaussian noise. Its power spectrum and the probability density functions of its discrete wavelet details are investigated and illustrated. Some examples based on simulated and real data are also ... View full abstract»

• ### Wavelet transform-based strain estimator for medical imaging

Publication Year: 1998, Page(s):65 - 68
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A new signal processing algorithm based on a wavelet transform (WT) is proposed for instantaneous strain estimation in acoustic elastography, where the interior elasticity distribution of a biological tissue is imaged. The proposed estimator weights ultrasonic echo signals acquired before tissue compression by a Gaussian window function and uses the resulting waveform as a mother wavelet to calcul... View full abstract»

• ### A new complexity prior for multiresolution image denoising

Publication Year: 1998, Page(s):637 - 640
Cited by:  Papers (1)
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Application of the minimum description length (MDL) principle to multiresolution image denoising has been somewhat unsuccessful to date. This disappointing performance is due to the crudeness of the underlying prior image models, which lead to overly sparse solutions. We propose a new family of complexity priors based on Rissanen's (1984, 1992) universal prior for integers, which produces estimate... View full abstract»

• ### Wavelet and principal component subspace analysis for function approximation and data compression

Publication Year: 1998, Page(s):409 - 412
| | PDF (380 KB)

A method for a wavelet analysis of time series or image data is presented in which correlation among the data component is used to increase the efficiency of function approximation and data compression. For this purpose, the sub-space analysis of the principal components is utilized. Wavelet coefficients belonging to the first component are derived and stored for function reconstruction. A residua... View full abstract»

• ### Trained wavelets used to detect epileptic spikes

Publication Year: 1998, Page(s):285 - 288
Cited by:  Papers (2)
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Although many authors developed different methods for automatic detection of epileptic spikes, so far a method for clinical routine has not yet evolved. Moreover the ambiguous definition of these waves makes the detection more difficult. This paper presents a new procedure to automatically detect and localise the interictal epileptic spikes based on their shape and duration. We used the discrete w... View full abstract»

• ### The analysis of dynamic EEG signals by using wavelet packets decomposition

Publication Year: 1998, Page(s):85 - 88
| | PDF (304 KB)

Wavelet transformation is employed to investigate the nonstationarity of clinical EEG signals and other medical signals. In order to detect 4 kinds of EEG rhythms, wavelet packet analysis is used for designing filters with different frequency characteristics. Two kinds of EEG data with different brain function states are analyzed and compared. It is indicated from the experimental results that the... View full abstract»

• ### Instantaneous changes in the heart rate variability during head-up tilt revealed by positive time-frequency distribution

Publication Year: 1998, Page(s):253 - 256
| | PDF (260 KB)

Energy distribution of the heart rate variability signal is perturbed in patients with impaired cardiac function compared to normal subjects (Li et al., 1997). We hypothesized that the energy distribution reflects the changes in autonomic regulation that are not exposed by conventional methods estimating the power in the empirically defined frequency ranges. To test this hypothesis instantaneous p... View full abstract»

• ### Construction of local bases

Publication Year: 1998, Page(s):185 - 188
| | PDF (312 KB)

A local signal analysis represents the properties of a signal on selected bounded domains. In the one-dimensional case, the local signal analysis can be based on orthogonal projections which are related to the subdivision into intervals. The multidimensional situation is more difficult to analyze. Some ideas of how to transfer the one-dimensional case to the multidimensional one are considered, re... View full abstract»

• ### Denoising of non-stationary signals using optimized Karhunen-Loeve expansion

Publication Year: 1998, Page(s):621 - 624
Cited by:  Papers (1)
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We show that denoising a non-stationary signal is possible by means of a Karhunen-Loeve (KL) expansion optimized by an entropy criterion. This criterion is used to segment the noisy signal and to choose the most parsimonious KL representation possible for each segment. The entropy of the KL coefficients for different window lengths determines the appropriate number and the lengths of the windows. ... View full abstract»

• ### Computing derivatives of scaling functions and wavelets

Publication Year: 1998, Page(s):357 - 360
Cited by:  Papers (1)
| | PDF (288 KB)

This paper provides a general approach to the computation, for sufficiently regular multiresolution analyses, of scaling functions and wavelets and their derivatives. Two distinct iterative schemes are used to determine the multiresolution functions, the so-called cascade' algorithm and an eigenvector-based method. We present a novel development of these procedures which not only encompasses both... View full abstract»

• ### Signal reconstruction from the reassigned spectrogram

Publication Year: 1998, Page(s):21 - 24
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The problem of recovering the original time series from the time-frequency representation (TFR) created by the reassigned spectrogram is considered. It is shown that the original time series can be recovered (to within a multiplicative constant) given certain conditions on the overlap used to create the original short-time Fourier transform (ST-FT) upon which the reassigned spectrogram is based. T... View full abstract»

• ### Optimum filter design for thea trous algorithm

Publication Year: 1998, Page(s):125 - 128
| | PDF (224 KB)

Thea trous algorithm is an efficient method to compute the continuous wavelet transform at dyadic scale. It consists of a bandpass and a lowpass filter. The bandpass filter is the dilated by two mother wavelet samples and the lowpass filter is a trous. The computation accuracy of the algorithm is dependent on the choice of the lowpass filter. This paper derives a closed-form solution for the lowpa... View full abstract»

• ### Two-dimensional nonseparable multiwavelet transform and its application

Publication Year: 1998, Page(s):61 - 64
| | PDF (536 KB)

Two-dimensional compactly supported, orthogonal non-separable multiwavelets and filter-banks are presented. We investigate the general subset of multiwavelets with a corresponding polyphase matrix that can be factored as a product of degree-1 factors in one variable. We consider in particular multiwavelets with vanishing moments. The number of vanishing moments that can be achieved increases with ... View full abstract»

• ### The time-dependent weighted average instantaneous frequency

Publication Year: 1998, Page(s):97 - 100
Cited by:  Papers (4)  |  Patents (1)
| | PDF (288 KB)

It is often claimed that instantaneous frequency, taken as the derivative of the phase of the signal, is appropriate' or meaningful' only for monocomponent signals, and that for multicomponent signals a weighted average of the individual instantaneous frequencies should be used. That is fine as a definition, but generally difficult to do in practice because there is no systematic and general met... View full abstract»

• ### Analysis of multiresolution image denoising schemes using generalized-Gaussian priors

Publication Year: 1998, Page(s):633 - 636
Cited by:  Papers (10)
| | PDF (452 KB)

We investigate various connections between wavelet shrinkage methods in image processing and Bayesian estimation using generalized-Gaussian priors. We present fundamental properties of the shrinkage rules implied by the generalized-Gaussian and other heavy-tailed priors. This allows us to show a simple relationship between differentiability of the log prior at zero and the sparsity of the estimate... View full abstract»

• ### On the extension for the orthogonalization' of continuous wavelet transformation

Publication Year: 1998, Page(s):137 - 140
| | PDF (232 KB)

The wavelet systems with continuous parameters used in continuous wavelet transform are not orthogonal. However, by extending the function space by tensor product into the function space of the functions with two variables, we can orthogonalize this function system in a sense. In this paper, a systematic method for this kind of orthogonalization is proposed, by using the eigenfunction problem of a... View full abstract»

• ### Time-frequency signal analysis of the acoustic emission of Formula 1 engines

Publication Year: 1998, Page(s):441 - 444
Cited by:  Papers (2)  |  Patents (1)
| | PDF (308 KB)

Presents the application of frequency domain signal analysis methods to estimation of engine performance parameters from measurements of sound intensity. The method is applied to measurements obtained from Formula 1 (F1) race cars during practice and race conditions. The paper begins by summarizing the issues of interest in the analysis of engine noise from high-performance engines, the informatio... View full abstract»

• ### Research of stationary partitions in nonstationary processes by measurement of spectral distance with the help of nondyadic Malvar's decomposition

Publication Year: 1998, Page(s):429 - 432
Cited by:  Papers (2)
| | PDF (316 KB)

In this article, we propose a simple algorithm allowing the research of stationary partitions in locally stationary processes, by use of adapted local bases like the local DCT or the short-time Fourier transform. The algorithm aims at finding some windows of which width is adapted to the rate of change in the spectrum. A similar approach was proposed by Adak (1995), who detected changes over time ... View full abstract»