Non-destructive surface inspection by shearing speckle interferometry

摘要

The apparatus for non-destructive surface inspection using Speckle Pattern Shearing Interferometry (Shearography) of an object (2) illuminates the object with coherent light from light source (1), which is diffusely reflected and passed through a Shearing arrangement (3) and an optical system to form a Null Shearogram and having a Loading Shearogram to produce in-plane or out-of-plane deviations by selection in the optical elements (11, 12). The object surface is illuminated from two or more directions (+Oxz, -Oxz with relation to +Oyz, -Oyz) sequentially and the pure in-plane and out-of-plane deviations are computer-generated by combining the resulting Shearograms.