DocumentCode :
3141157
Title :
Application of Stationary Wavelet Transforms to Ultrasonic Crack Detection
Author :
Fan, Xianfeng ; Zuo, Ming J. ; Wang, Xiaodong
Author_Institution :
Dept. of Mech. Eng., Alberta Univ., Edmonton, Alta.
fYear :
2006
fDate :
38838
Firstpage :
1432
Lastpage :
1436
Abstract :
Ultrasonic-based pulse-echo technique has been widely used for non-destructive crack detection. The noisy ultrasonic signals reflected by inhomogeneous materials and other effects add difficulty to pulse echo extraction. In order to address this issue, a method is proposed in this paper to remove noise. Firstly, the raw signal is processed using stationary wavelet transform. Secondly, kurtosis is employed as a criterion to retain the appropriate wavelet coefficients on a specific scale, and to zeroize all wavelet coefficients on other scales. Thirdly, the remaining wavelet coefficients are shrunken by a soft- threshold rule using universal threshold sigmaradic2log(n), the maximum standard deviation of wavelet coefficients on all scales before being zeroized, and n is the data length. Fourthly, cross-correlation analysis between the de-noised signal and the transmitted pulse signal is conducted. Finally, the time-of-flight of the pulse in a material is measured and the flight distance is calculated. Experimental results indicate that the proposed method can detect the crack position effectively
Keywords :
correlation methods; crack detection; signal denoising; ultrasonic reflection; wavelet transforms; cross-correlation analysis; inhomogeneous materials; noisy ultrasonic signals reflection; pulse-echo technique; signal denoising; stationary wavelet transform; time-of-flight; ultrasonic crack detection; Continuous wavelet transforms; Discrete wavelet transforms; Noise reduction; Pulse measurements; Signal analysis; Signal processing; Ultrasonic variables measurement; Wavelet analysis; Wavelet coefficients; Wavelet transforms; Stationary wavelet transform; crack detection; cross-correlation analysis; de-noising; ultrasonic signal;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Electrical and Computer Engineering, 2006. CCECE '06. Canadian Conference on
Conference_Location :
Ottawa, Ont.
Print_ISBN :
1-4244-0038-4
Electronic_ISBN :
1-4244-0038-4
Type :
conf
DOI :
10.1109/CCECE.2006.277532
Filename :
4054905
Link To Document :
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