改进小波阈值滤波融合VMD的地震事件信号随机噪声压制方法OA

To address the limitations of traditional single denoising method when processing nonlinear and non-stationary seismic signals,we propose a joint denoising method based on variational mode decomposition(VMD)and an improved wavelet threshold decomposition(IWTD).First,a standard VMD decomposition is performed on the seismic signal based on the pre-set number of mode decomposition layers and penalty factors.Second,the intrinsic modal functions(IMFs)obtained from the VMD decomposition are filtered using cross-correlation coefficients to precisely separate signal-dominated components and noise-dominated components.Next,a continuously differentiable improved wavelet threshold function is constructed to perform secondary refined denoising of the selected noise-dominated IMFs,thereby addressing the inherent shortcomings of tradi-tional hard threshold function(discontinuity)and soft threshold function(constant bias).Finally,a weighted comprehensive evaluation scheme for signal denoising is designed to comprehensively assess multiple critical indicators,including effective bandwidth envelope consistency,noise suppression rate,power spectrum consis-tency,signal kurtosis,and arrival time detection accuracy.The experimental results of both synthetic signals and actual seismic signals demonstrate that,this method achieves comprehensive scores of 76.299 8 and 76.227 2,respectively,exceeding other models by up to 29.782 5 and 27.177 1 compared to empirical mode decomposition(EMD),Wiener filtering,and wavelet threshold filtering.It better preserves the amplitude-frequency characteristics and effective energy of seismic signals,providing a more reliable data foundation for subsequent high-precision phase picking and seismic sequence analysis.