Research on Signal Processing Technology of Ultrasonic Non‐Destructive Testing Based on EEMD Combined with Wavelet Packet

Abstract

When processing ultrasonic non‐destructive testing signals, the ensemble empirical mode decomposition (EEMD) method can eliminate the phenomenon of modal aliasing, and the processing effect is better than the empirical mode decomposition (EMD) method. However, in signal reconstruction, the intrinsic mode function (IMF) will be eliminated directly, resulting in the loss of some signals and errors. Therefore, a signal processing method of ultrasonic non‐destructive testing based on EEMD combined with wavelet packet is proposed in this paper. In this method, the signal is preprocessed by wavelet packet, and then decomposed by EEMD. The correlation coefficient method is used in reconstruction. This method not only retains the advantages of EEMD, but also uses the characteristics of wavelet packet decomposition of high frequency and low frequency to ensure the integrity of the signal. Finally, the simulation and actual measurement signals are used for verification. Compared with the EEMD algorithm, the signal‐to‐noise ratio is increased by 31.60% and the root mean square error is reduced by 31.63%, and the cross‐correlation coefficient is increased by 22.09%. This method is more suitable for ultrasonic non‐destructive testing signal processing. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.