Abstract:In view of the constant deviation of the soft threshold function and the discontinuity of the hard threshold function, which results in low accuracy of signal denoising and pseudo-Gibbs phenomena, we propose an improved threshold function. We further prove its continuity, gradualness and deviation mathematically. When used with the four simulated signals with Gaussian white noise, we find that it not only improves the signal-to-noise ratio of the signal, but also compensates for the signal distortion caused by the soft and hard threshold functions. The threshold function proposed in this paper is applied to the air-gun artificial seismic source, and a conclusion consistent with the simulated signal is obtained. At the same time, compared with band-pass filtering, the method proposed in this paper can completely retain the phase and amplitude information of the signal, which proves that the improved threshold function has certain feasibility in improving the signal-to-noise ratio of the air-gun artificial source signal.
ZHOU Yunyao,WANG Haibin,XIANG Ya et al. Application of Lifting Wavelet with Improved Threshold Function in Artificial Seismic Source[J]. jgg, 2021, 41(6): 639-645.