Automatic specklegram fringe analysis by using symmetry evaluation of the Θ-scanning function

Abstract

New approaches are applied to overcome the difficulty of accurate angle measurements in specklegram information processing by introducing a prism rotator for compensation and by using symmetry evaluation. Together with slit scanning and the fast Fourier transform procedure, speckle random noise has been effectively suppressed, and accurate measurements of Theta and s are achieved. The method we present makes it possible to process the specklegram information automatically. The experimental setup is described in detail. The principles and experimental curves are given.