基于VMD与改进小波阈值的地震信号去噪方法研究

Seismic signal denoising method based on VMD and improved wavelet threshold

地震资料通常包含大量噪声,为了有效去除噪声,提高地震信号的信噪比,这里提出一种联合变分模态分解(VMD)与改进小波阈值去噪的方法。相比于传统的小波阈值函数,新构造的阈值函数克服了硬阈值函数的不连续性问题和软阈值函数中小波系数的恒定偏差问题,同时能根据实际情况灵活调节两个参数,以实现较好的阈值去噪效果。而VMD对非平稳信号分解具备较好的自适应性,能很好地应用于地震信号。将两种方法相结合可以获得更好的去噪效果。用本文提出的方法对仿真信号以及实际地震资料进行处理后,信噪比明显优于传统单一去噪方法。

Seismic data usually contain a lot of noise.In order to effectively remove noise and improve the signal-to-noise ratio of seismic signal,this paper proposes a method of combining Variational mode decomposition(VMD)with improved wavelet threshold denoising.Compared with the traditional wavelet threshold function,the new threshold function overcomes the discontinuity problem of hard threshold function and the constant deviation of wavelet coefficients in soft threshold function.At the same time,it can adjust two parameters flexibly according to the size of noise to achieve better threshold denoising effect.And VMD has good adaptability to non-stationary signal decomposition and can be applied to seismic signal.The combination of the two methods can obtain better denoising effect.The simulation signal processed by the method proposed show that the signal-to-noise ratio is obviously better than the traditional single denoising method in this paper.