Spatial phase-shift interferometry: implementation of an effective phase-recovery algorithm

Thanks to its robustness and reduced sensitivity to vibrations and air turbulence, spatial phase-shift interferometry (SPSI) is a measuring technique of particular value in industrial environments. Making use of a commercial CCD camera connected with a PC we have set up an essential system that acquires and processes the fringe pattern, extracting the relevant features of the phenomenon being observed. The basic algorithms for phase recovery are available from the literature. Here we present a variant of one of such algorithms and describe in detail its implementation in our SPSI system. Experimental results are presented, showing the effectiveness of the overall measuring chain.