Inverse algorithm for out-of-plane deformation in shearography

Shearography directly measures the first derivative of the object deformation, but cannot directly obtain the deformation distribution of the object, which brings much inconvenience to the analysis of the mechanical properties of the material. This paper introduces a phase reconstruction method based on image-side shearing amount and shearing direction, which can inversely calculate the object’s out-of-plane deformation distribution. The imaging area and imaging center of the measured object are determined through image segmentation and edge detection technology, and the shearing size and direction as well as the interference area can be accurately extracted. The experimental results show that the method can calculate the out-of-plane deformation distribution of shearography and the relative error of the maximum deformation value is about 1.65%.