INVERSE SCATTERING ALGORITHM APPLIED TO INFRARED THERMAL-WAVE IMAGES

We present an inverse scattering algorithm that makes possible the inv ersion of experimental thermal wave images of planar subsurface defect s. The method is based on a Green's function technique. It significant ly improves the spatial resolution and removes the blurring which is o therwise characteristic of thermal wave images. The method has been ap plied to materials ranging from plastics (diffusivity approximately 0. 001 cm2/s) to aluminum alloys (diffusivity approximately 0.5 cm2/s), a nd for depths ranging up to a few mm.