Sharp Detection of Event’s Onset in Seismic Signals With Asymmetrical Kaiser Window-Based S-Transform

2019 ◽  
Vol 16 (10) ◽  
pp. 1620-1624 ◽  
Author(s):  
Neha Singh ◽  
Pyari Mohan Pradhan
Author(s):  
Aleksander S. Serdyukov ◽  
Anton V. Azarov ◽  
Aleksander V. Yablokov ◽  
Tatiana V. Shilova ◽  
Valery D. Baranov
Keyword(s):  

2019 ◽  
Author(s):  
Aleksander S. Serdyukov ◽  
Aleksander V. Yablokov ◽  
Anton V. Azarov ◽  
Tatiana V. Shilova
Keyword(s):  

2017 ◽  
Vol 13 (3) ◽  
Author(s):  
Sunil Datt Sharma ◽  
Rajiv Saxena ◽  
Sanjeev Narayan Sharma

AbstractIn computational biology the development of algorithms for the identification of tandem repeats in DNA sequences is a challenging problem. Tandem repeats identification is helpful in gene annotation, forensics, and the study of human evolution. In this work a signal processing algorithm based on adaptive S-transform, with Kaiser window, has been proposed for the exact and approximate tandem repeats detection. Usage of Kaiser window helped in identifying short as well as long tandem repeats. Thus, the limitation of earlier S-transform based algorithm that identified only microsatellites has been alleviated by this more versatile algorithm. The superiority of this algorithm has been established by comparative simulation studies with other reported methods.


2020 ◽  
Vol 8 (4) ◽  
pp. T793-T801
Author(s):  
Nanke Wu ◽  
Huailai Zhou ◽  
Yuanjun Wang ◽  
Bo Zhang ◽  
Haitao Yan ◽  
...  

The synchrosqueezing generalized S-transform (SSGST) is commonly used to generate an isofrequency component of a signal by squeezing the decomposed frequency components of the signal. However, for seismic signals, the single-trace process can have a lack of lateral information in the squeezed results and lead to some discontinuous geologic information that will mislead the interpreter. Thus, to improve the stability of SSGST, we have developed a multichannel seismic trace squeezing method. Multichannel SSGST (MSSGST) considers the decomposed frequency components of neighboring traces of the analysis seismic trace and then reconstructs the center trace. Therefore, compared with SSGST, the multichannel processing improves the stability of the squeezing and produces more laterally continuous results that properly follow the geologic phenomenon. The effectiveness of MSSGST is validated using various field data. We use the application to demonstrate the potential of multichannel squeezing to perform well at (1) improving the energy focusing and continuity of the decomposed frequency components, (2) depicting the boundaries of geologic structures, and (3) identifying the thin layers.


2016 ◽  
Vol 59 (1) ◽  
pp. 43-53 ◽  
Author(s):  
DENG Gong ◽  
LIANG Feng ◽  
LI Xiao-Ting ◽  
ZHAO Jun-Meng ◽  
LIU Hong-Bing ◽  
...  

Geophysics ◽  
2017 ◽  
Vol 82 (5) ◽  
pp. O71-O81 ◽  
Author(s):  
Lin Wu ◽  
John Castagna

The S-transform is one way to transform a 1D seismogram into a 2D time-frequency analysis. We have investigated its use to compute seismic interpretive attributes, such as peak frequency and bandwidth. The S-transform normalizes a frequency-dependent Gaussian window by a factor proportional to the absolute value of frequency. This normalization biases spectral amplitudes toward higher frequency. At a given time, the S-transform spectrum has similar characteristics to the Fourier spectrum of the derivative of the waveform. For narrowband signals, this has little impact on the peak frequency of the time-frequency analysis. However, for broadband seismic signals, such as a Ricker wavelet, the S-transform peak frequency is significantly higher than the Fourier peak frequency and can thus be misleading. Numerical comparisons of spectra from a variety of waveforms support the general rule that S-transform peak frequencies are equal to or greater than Fourier-transform peak frequencies. Comparisons on real seismic data suggest that this effect should be considered when interpreting S-transform spectral decompositions. One solution is to define the unscaled S-transform by removing the normalization factor. Tests comparing the unscaled S-transform with the S-transform and the short-windowed Fourier transform indicate that removing the scale factor improves the time-frequency analysis on reflection seismic data. This improvement is most relevant for quantitative applications.


Author(s):  
Chengbin Liang ◽  
Zhaosheng Teng ◽  
Jianmin Li ◽  
Wenxuan Yao ◽  
Shiyan Hu ◽  
...  

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