The research on noise reduction of ground target vibration signal based on wavelet decomposition and EMD

Abstract

In order to solve the problems of identifying the remote ground vibration signals with complex signal components and low signal-to-noise ratio, this paper proposes a denoising method combining wavelet transform and empirical mode decomposition: Wavelet EMD Denoising. First, wavelet transform is applied to the noisy signal for initial noise reduction, then empirical mode decomposition is applied to the signal after initial noise reduction, then wavelet decomposition is applied to the sub signal for noise reduction again, and then the sub signal is filtered and synthesized to obtain a signal with high signal-to-noise ratio for subsequent processing and analysis. In this paper, EMD synthesis and wavelet EMD noise reduction processing are respectively carried out for the collected long-distance personnel vibration signal and vehicle vibration signal, and the time-frequency domain of the results of both are analyzed. It is proved that the wavelet EMD noise reduction proposed in this paper can effectively reduce the noise of this type of signal compared with EMD synthesis, and its frequency domain energy is more concentrated: the energy proportion of the frequency band where the effective signal of vehicle signal is located is increased by 29%, The proportion of energy in the frequency band where the effective signal of personnel signal is located is increased by 51%. The noise reduction effect is better than the traditional EMD synthesis algorithm.