Phase-stepping DSPI and its applications

The use of phase-stepping technique in speckle interferometry allows a quantitative evaluation of the interference phase with high accuracy and offers the possibility of automated interferogram processing. In this paper, an automated measuring system based on this technique is described. The effects of system parameters on the phase extraction are discussed, some applications in the fields of transient event analysis, in-plane deformation measurement, vibration analysis and nondestructive testing are presented.