A wave propagation-based model for diffuse illumination digital shearography

Abstract

Conventional digital shearography of rough objects uses plane wave illumination. For highly reflecting test objects, application of shearography is hampered because saturation in the speckle intensity results in loss of information. Here, a mathematical model for diffuse illumination digital shearography is presented. The numerical model incorporates the diffuse illumination of a test object and the processing of the scattered light by a Michelson-type shearography setup. The main advantage of diffuse illumination is the avoidance of image saturations resulting in enhanced strain measurements.