Fundamental limits in estimating light pattern position

Abstract

Expressions for the minimum number of photons required to measure the position of a light pattern on a noncoherent detector array with a desired accuracy are obtained from the Cramér–Rao lower bounds. The dependence of the Cramér–Rao bound on the shape, on the statistical properties of the intensity, on spatial sampling by the detector array, and on the array area is examined quantitatively. Examples of linear and nonlinear algorithms for measuring the pattern position with accuracies approaching the Cramér–Rao bound are presented. The analysis is carried out for photon statistics modeled as conditional Poisson processes.