An instantaneous phase shifting ESPI system for dynamic deformation measurement

Abstract

In this study, an ESPI measurement system which is capable of grabbing four phase-shifted interferometric images instantaneously (or simultaneously) is developed for out-of-plane dynamic deformation measurement. A new polarization phase-shifting interferometric system is designed. The system constructed allows the four phase-shifted images to be grabbed by four CCD simultaneously. And digital image correlation method was applied to correct the pixel position mismatch among the four images. Thereafter, the phase at each pixel can be calculated for further obtaining the out-of-plane displacement. Test of the system on an edge-clamped circular plate heated from behind is demonstrated. The results reveal that the proposed system is applicable for the dynamic deformation measurement.