Improving time-dependent deformation measurement

Phase-shifted digital speckle shearography (PSDSS) is a technique that uses the interference patterns of light waves to measure the slope of a deformed surface. It shows promise for non-destructive testing of aircraft structures, specifically for strain analysis and noncontact flaw detection. Yet because it requires at least three consecutive images, it is more applicable for measuring static shape changes. Recently, researchers have focused on expanding the technique to capture deformations occurring over time. One such approach, the phase of difference method, takes one image of an object after deformation and several beforehand. We adopted this method to PSDSS, but noise reduced the image quality. For this system to be effective, new algorithms are needed to process the images.A new method for characterizing shape changes over time may improve nondestructive testing.