Development of a phase (contrast) reversal speckle interferometric system for in-plane displacement measurement with twofold sensitivity

摘要

A phase reversal speckle interferometric (PRSI) system is developed for precise measurement of in-plane displacement component of a deformation vector with twofold measuring sensitivity. In the system, the phase (contrast) reversal is accomplished by varying the pressure within a air filled quartz cell inserted in one of the observation arms of a dual beam symmetric illumination-observation arrangement. The work reported here is classified into two parts: The first part illustrates a novel real-time phase reversal speckle photography (PRSP) technique for exact n-phase shift calibration using a two wave coupling arrangement in a BaTiO_3 photorefractive crystal as a recording medium. The second part consists of simultaneously providing object deformation and an exact phase shift of re between the exposures using PRSI system to achieve twofold measuring sensitivity