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Harmonic wavelet transform

About: Harmonic wavelet transform is a research topic. Over the lifetime, 9602 publications have been published within this topic receiving 247336 citations.


Papers
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Proceedings ArticleDOI
26 Aug 2001
TL;DR: In this article, the dynamic range of wavelet transform coefficients and computational complexity of the wavelet transforms in JPEG-2000 Part-1 standard were examined, and their effect on coding efficiency was investigated.
Abstract: Numerous issues associated with wavelet transforms in the JPEG-2000 Part-1 standard (i.e., ISO/IEC 15444-1) are studied. The dynamic range of wavelet transform coefficients and computational complexity of wavelet transforms are examined. Also, the effect of wavelet transforms on coding efficiency is investigated. The information presented may prove beneficial to those developing JPEG-2000 codec implementations.

51 citations

Journal ArticleDOI
TL;DR: In this paper, a wavelet packet transform (WPT) based approach is proposed for filtering of short-period seismic signals. But it is not suitable for the analysis of nonstationary signals like seismograms.
Abstract: The wavelet packet transform gives information in both the time and frequency domains, and it is very useful for describing nonstationary signals like seismograms. Moreover, this structure is dependent on the signal under study; hence we can choose the time-frequency decomposition more appropriate for every signal. In this article, we propose a new method for filtering based on the wavelet packet transform. This approach uses different parameters for filtering, depending on the band of frequencies that we are analyzing. This filtering is employed in order to achieve a high signal-to-noise ratio (SNR) and low distortion. We first apply the method to synthetic signals that we have contaminated with noise. In this way, the shape of the whole output signal and the onset time of the first pulse can be compared to the ideal signal. Finally, we apply it to short-period seismograms recorded at the local seismic network of the University of Alicante in southeastern Spain. The method proposed is compared with conventional passband filters and other methods based on wavelets. The comparison demonstrates that our method achieves a higher SNR without introducing noticeable distortion.

51 citations

Journal ArticleDOI
TL;DR: In this paper, the authors propose a method to map instantaneous polarization attributes of seismic signals in the wavelet domain and explicitly relate these attributes with the Wavelet-transform coefficients of the analyzed signal.
Abstract: Complex-trace analysis is the method of choice for analyzing polarized data. Because particle motion can be represented by instantaneous attributes that show distinct features for waves of different polarization characteristics, it can be used to separate and characterize these waves. Traditional methods of complex-trace analysis only give the instantaneous attributes as a function of time or frequency. However, for transient wave types or seismic events that overlap in time, an estimate of the polarization parameters requires analysis of the time-frequency dependence of these attributes. We propose a method to map instantaneous polarization attributes of seismic signals in the wavelet domain and explicitly relate these attributes with the wavelet-transform coefficients of the analyzed signal. We compare our method with traditional complex-trace analysis using numerical examples. An advantage of our method is its possibility of performing the complete wave-mode separation/filtering process in the wavelet ...

51 citations

Journal ArticleDOI
TL;DR: An efficient algorithm is developed for computing the continuous wavelet transform or wideband ambiguity function on a grid whose samples are spaced uniformly in time but placed arbitrarily in scale.
Abstract: An efficient algorithm is developed for computing the continuous wavelet transform or wideband ambiguity function on a grid whose samples are spaced uniformly in time but placed arbitrarily in scale. The method is based on the chirp z transform and requires the same order of computation as constant-bandwidth analysis techniques, such as the shorttime Fourier transform and narrowband ambiguity function.

50 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202323
202274
20213
20207
20196
201831