The compensation of deformation measurement in large field of View based on Digital Speckle Pattern Interferometry

Digital speckle pattern interferometry (DSPI) is a high-precision measurement method for measuring the surface deformation of an object. Compared with other measurement techniques, it has the advantages of full-field measurement, real-time, non-contact, high precision and high sensitivity, which has made the technology widely concerned by the measurement community since its birth.However, the application calculation of most of the existing digital speckle interference is based on the paraxial and approximate vertical calculations, ignoring the large fluctuation range of the angle between the laser illumination direction and the CCD observation direction. It makes the measurement error of large field of view larger when the size of the object is large. Therefore, when measuring a large field of view, it is necessary to correct the existing measurement formula. This paper proposes a new method for applying digital speckle interference to large field of view measurement. Based on the basic principle of digital speckle interferometry, the corresponding compensation coefficient is obtained through mathematical relationship to compensate the measurement result of large field of view.