On EMD based adaptive de-noising method for signal processing

Abstract

In this paper, Empirical Mode Decomposition (EMD) is employed to eliminate noises existing in experimentally acquired ultrasonic guided Lamb wave signals. The detailed procedures are provided and several examples involving both narrowband and wideband signals are given to show the validity of the proposed de-noising method. Comparisons are made with the results obtained by the well-known Wavelet method. It is found that both EMD-based and Wavelet-based de-noising methods can yield acceptable results. It is also found that EMD-based de-noising method can separate noises from noise-polluted signals more efficiently due to its adaptive nature in the de-noising process, and that less empirical information is required as compared with the Wavelet-based de-noising method. Based on the results reported herein, one may conclude that EMD-based de-nosing method can be effectively used to get a clear and significant response signal, an important step in the area of structural health monitoring. Further research should be made to establish a reliable criterion for separating a useful IMF from noise components in general cases.