Research on Noise Reduction Method of Underwater Ultrasonic Echo Signal Based on EWT-FastICA
Aiming at the problem that underwater ultrasonic non-destructive testing is susceptible to noise signal interference,resulting in low defect detection accuracy,an underwater ultrasonic echo signal detection method based on empirical wavelet transform combined with fast independent component analysis is proposed.First,the EWT algorithm is used to decompose the ultrasonic echo signal to obtain the intrinsic mode function(IMF)of different scales;then the fuzzy entropy value of each modal component is calculated by the fuzzy entropy algorithm,and the required modal components are screened out;finally the FastICA operation is performed to reconstruct the screened IMF,and the blind source separation of the ultrasonic echo signal and the noise signal is realized,and a pure ultrasonic echo signal is obtained in the end.The simulation and experimental examples show that the noise reduction method combined with EWT-FastICA improves the mode mixing,endpoint effect,over-envelope and under-envelope phenomena that occur in traditional empirical mode decomposition,the noise reduction process is faster and more accurate,and can be applied to similar underwater ultrasonic detection signal noise reduction processing.
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