Fourier phase shift location estimation of unfocused optical point spread functions

摘要

Many applications in machine vision require the subpixel evaluation of the position of the center of a patch in a sampled image. The usual technique of calculation relies on the ‘centroid’ method (CCM) but it has been recently shown that this method is very sensitive to additive perturbations of the signal (distortions, noise, DC-offset etc.). Another method (FPS) has been proposed which stems from the frequency dependence of the argument of the Fourier transform. It has been demonstrated in the case of a focused Airy pattern that such a method is performed better and is also largely immune to perturbations. The aim of this paper is to show from a computer simulation that the advantages of FPS over CCM still hold when dealing with ring patterns (internal oscillations) such as those involved in defocused point source images.