Reconstruction of the defect shape from lock-in thermography phase images

We present a method for reconstructing the shape of buried planar defects supposed to be infinitely thick front optical lock-in thermography phase images. Several image processing algorithms are combined, to extract quantitative defect information from a series of phase images (phasegram) in a semi-automatic way. It is shown, that the depth and the shape of a planar defect can be retrieved.