Digital processing of dual-plate speckle photography data.

Dual-plate speckle photography provides a technique for canceling rigid body displacements of an object by recording the images that correspond to the two deformation states on separate photographic plates. When both plates are positioned with a glass base between the emulsions and illuminated by a laser beam, a pattern of circular fringes is formed. Speckle displacement can be determined by measuring the distance between the fringe pattern center and the undiffracted laser beam. The performance of an algorithm for automatic analysis of these fringes is evaluated by using computer-generated fringe patterns. Accuracy is determined for different values of speckle displacements and fringe visibilities.