Sub-pixel Profiling

A procedure is described that enables a high resolution profile to be obtained across an edge or line. The method works by first performing a sub-pixel estimation of each point on the edge or line assuming a parabolic sub-pixel profile. A second stage fits a high order model along the length of the line, allowing any bias in the original sub-pixel fit to be estimated by applying a low order model to the residuals. Successive rows within the image are then fused to increase the sample rate and provide a sub-pixel profile of the line. The procedure is illustrated by obtaining the profile of a noisy edge