Transient-Spatial Pattern Mining of Eddy Current Pulsed Thermography Using Wavelet Transform

Yang Hailong, Gao Bin, Tian Guiyun, Ren Wenwei, Woo Wai Lok

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

Eddy current pulsed thermography(ECPT) is an emerging Non-destructive testing and evaluation(NDT & E) technique, which uses hybrid eddy current and thermography NDT & E techniques that enhances the detectability from their compensation. Currently, this technique is limited by the manual selection of proper contrast frames and the issue of improving the efficiency of defect detection of complex structure samples remains a challenge. In order to select a specific frame from transient thermal image sequences to maximize the contrast of thermal variation and defect pattern from complex structure samples, an energy driven approach to compute the coefficient energy of wavelet transform is proposed which has the potential of automatically selecting both optimal transient frame and spatial scale for defect detection using ECPT. According to analysis of the variation of different frequency component and the comparison study of the detection performance of different scale and wavelets, the frame at the end of heating phase is automatically selected as an optimal transient frame for defect detection. In addition, the detection capabilities of the complex structure samples can be enhanced through proper spatial scale and wavelet selection. The proposed method has successfully been applied to low speed impact damage detection of carbon fibre reinforced polymer(CFRP) composite as well as providing the guidance to improve the detectability of ECPT technique.
Original languageEnglish
Pages (from-to)768-778
JournalChinese Journal of Mechanical Engineering
Volume27
Issue number4
Early online date25 Jul 2014
DOIs
Publication statusPublished - Jul 2014

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