A wide adaptability deconvolution technique for ultrasonic nondestructive testing
YANG Ke-ji1, FANG Wen-ping1, HUANG Yi-chun2, QIAO Hua-wei1
(1. State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou 310027, China;
2. Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China)
A new wide adaptability deconvolution technique based on wavelet transform and particle swarm optimization (PSO) was developed to increase the resolution of ultrasonic nondestructive testing (UNDT) of composite materials. The original ultrasonic echo signal was de-noised and the position set of ultrasonic reflection coefficient was determined by using wavelet transform multi-resolution analysis. Then PSO was adopted to solve the ultrasonic reflection coefficient amplitudes corresponding to the position set, so as to eliminate the distorted wavelets smoothness effect and improve the detection resolution. Mean while, limitations of the traditional methods, such as only suitable for stationary ultrasonic signal, white noise and prior knowledge provided beforehand, were broken through by the new technique. Simulation and experimental results showed that the new method could greatly improve the ultrasonic testing resolution compared with the conventional deconvolution technique, and its wide adaptability as well as strong robustness was demonstrated．
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