Subaperture testing approaches: a comparison

Abstract

Two methods of reducing subaperture interferograms to produce full aperture aberration coefficients now exist: the Kwon-Thunen and the simultaneous fit method. The results of a numerical comparison show that for no flat-to-flat alignment the two work equally well and are equally sensitive to both higher-order noise and random noise. For ideal flat-to-flat alignment the Kwon-Thunen approach is less sensitive to noise by a factor of ~3. The simultaneous fit method requires fewer sample points and runs faster than the Kwon-Thunen method.