Research and application of ultrasonic signal detection based-on wavelet-time entropy

Ultrasonic signal detection is one kind of the non-destructive testing methods, and it can be non-destructive inspection of the internal defects of materials or mechanical components. One of the difficulties of ultrasonic signal detection is the detection of the echo signal in the ultrasonic signal. With the wavelet transform and Shannon entropy theory, the wavelet-time entropy algorithm is introduced in this paper. And the numerical simulations are carried out to prove the feasibility of this algorithm in abnormal signal detection. An improved wavelet-time entropy algorithm is put forward in this paper. The high-frequency coefficients of wavelet transform are replaced by the low-frequency coefficients, and the optimal width of window is worked out for actual ultrasonic signal. The results show that this improved wavelet-time entropy algorithm can effectively detect the echo signal in ultrasonic signal.