Subfringe holographic interferometry by computer-based spatial-carrier fringe-pattern analysis

A computer-based technique for the highly sensitive holographic interferometry has been proposed and verified by experiment. In contrast to the conventional contour-fringe technique, a carrier-fringe pattern is Fourier transformed and processed in its spatial frequency domain as well as in its spatial signal domain. The technique has a much higher sensitivity than the conventional contour fringe technique and is capable of fully automatic distinction of the sign of the deformation.