Image Moment based Wavefront Sensing for In situ Full-field Image Quality Assessment

A new concept of using focus-diverse point spread functions (PSF) for modal wavefront sensing (WFS) is explored. This concept is based on relatively straightforward image moment analysis of measured PSFs, which differentiates it from other focal-plane WFS techniques. The presented geometric analysis shows that the image moments are nonlinear functions of wave aberration coefficients but notes that focus diversity essentially decouples the coefficients of interest from others, resulting in a set of linear equations whose solution corresponds to modal coefficient estimates. The presented simulations suggest the potential of this method in in-situ full field image quality assessment and deterministic alignment control of wide field imaging systems.