Time Aliasing Problem in Pulsed Phased Thermography

摘要

Pulsed phased thermography (PPT) is a well-known processing method of non-destructive testing (NDT) by infrared thermography. This method is based on the frequency analysis of the images obtained from pulsed infrared thermography. The Fast Fourier Transform (FFT) is generally used for this technique. Such a method faces important time aliasing problems. Particularly important when slow infrared cameras are used and also in case of inspection of high thermal conductivity material like aluminum. Moreover, the oddness of the phase function, which is often the interesting part of the frequency response of the experiment increases dramatically this problem.