Contrast enhancement in crack detection by stimulated differential infrared radiometry: modelisation and experiments

Abstract Usually sample surface structures generate large flunctuations of the photothermal response due to local variations of optical, thermal and geometrical properties which mask the crack signal when using single detection ir radiometry. Demonstrated experimentally and theoretically is the ability of a differential stimulated ir detection scheme to obtain a better contrast in crack detection on real samples. A finite element simulation confirms the magnitude and shape of the signals for vertical and slanted cracks.