Digital shearography for slope measurement

This paper presents an electronic speckle shearing interferometry optical method for the full field measurement of the slope of an object. The object under study is placed on a rotatable platform and illuminated by an expanded laser beam. Its image is recorded by a shearing CCD camera and stored directly into a computer. By recording the two images before and after giving the object a small angle of rotation, the resulting correlation fringe pattern which represents the object surface slope can be obtained. Theory of the new method and some experimental results are presented.