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Spectral decomposition and de‐noising via time‐frequency and space‐wavenumber reassignment
Author(s) -
Han Li,
Sacchi Mauricio D.,
Han Liguo
Publication year - 2014
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/1365-2478.12088
Subject(s) - deconvolution , thresholding , energy (signal processing) , computer science , seismic trace , frequency domain , noise (video) , algorithm , seismic migration , time domain , time–frequency analysis , passive seismic , geology , mathematics , seismology , artificial intelligence , telecommunications , statistics , computer vision , image (mathematics) , radar , wavelet
The reassignment method remaps the energy of each point in a time‐frequency spectrum to a new coordinate that is closer to the actual time‐frequency location. Two applications of the reassignment method are developed in this paper. We first describe time‐frequency reassignment as a tool for spectral decomposition. The reassignment method helps to generate more clear frequency slices of layers and therefore, it facilitates the interpretation of thin layers. The second application is to seismic data de‐noising. Through thresholding in the reassigned domain rather than in the Gabor domain, random noise is more easily attenuated since seismic events are more compactly represented with a relatively larger energy than the noise. A reconstruction process that permits the recovery of seismic data from a reassigned time‐frequency spectrum is developed. Two approaches of the reassignment method are used in this paper, one of which is referred to as the trace by trace time reassignment that is mainly used for seismic spectral decomposition and another that is the f − x spatial reassignment that is mainly used for seismic de‐noising. Synthetic examples and two field data examples are used to test the proposed method. For comparison, the Gabor transform method, inversion‐based method and common f − x deconvolution method are also used in the examples.