An improved shearography technique for dynamic deformation measurement

Abstract

Dynamic deformation measurement is a hot topic in optical interferometry research. Currently, most proposed solutions in this field cannot simultaneously meet the fundamental requirements of accuracy and robustness, because these methods assume that the speckle field is constant during deformation or utilize iteration algorithm that generates a great deal of computation. In this paper, an improved shearography technique is presented. The fringe pattern is generated by the product of the speckle images preprocessed by frequency filter, and then the phase related to the deformation can be extracted from fringe pattern. Since only one image in deformed stage is used, the proposed method can be well applied for dynamic deformation measurement. Moreover, the proposed method has much more immunity to the fluctuation of speckle field compared with conventional method.