Comparison of Fourier and wavelet analyses for defect detection in lock-in and pulse phase thermography

This paper demonstrates how the wavelet analysis can be used as an alternative tool to fast Fourier transform in case of lock-in thermography (giving similar qualitative results) and pulse phase thermography method (where the time information is of consideration) in order to improve its analysis capabilities for the price of higher computational cost. Besides of theoretical information about application of those transforms, for both of them qualitative experimental results are shown. This paper presents the chosen results of experiments realized at the Institute of Electronics, Technical University of Lodz.