Digital image correlation method (DICM) application in speckle phase-shift of shear speckle defect detection

摘要

The laser shear speckle technique has a distinct advantage in non-destructive testing (NDT) field. Our main objective of our investigation has been to obtain some knowledge of digital image correlation method (DICM) applicated in speckle shearing phase-shift for damage detection. In many cases it uses laser speckle shearing technique with subtract to gain the fringe pattern, which method processes fast, but it can only gain low quality image. Meanwhile, the method of subtraction requires high quality of the original image, these features make it not suitable for high precision applications in many situations. This paper brought forth a method, which combined digital image correlation method (DICM) and phase-shifting method, to achieve shearography speckle phase shifting image in the tire defect detection according according to phase shifting image. The digital image speckle correlation technique can greatly reduce the requirements on original image quality and the number of the original images, and these features makes it easier to gain clear phase image combined with phase-shifting technique.