Axial localization of phase objects using a statistical contrast algorithm

Abstract

A novel technique for the localization of refractive test objects using the axial variation of a reconstructed wavefront is presented. The wavefront phase is plotted at equally-spaced axial planes within the wavelength of the light source used. For each transverse phase plot, standard deviation (SD) values are obtained. The axial variation of the SD values yield a contrast map showing the spatial features of the wavefront. To locate the test object along the axial direction, the contrast maps are correlated to a Gaussian test function. The correlation yields a well-behaved curve facilitating the enhanced localization of the test object.