The accuracy of the Shack-Hartmann wavefront sensor for measuring the wavefront distortion is mainly dependent upon the measuring accuracy of the centroid of each spot. A modified center detection algorithm, which uses some power from the photon events of
Li, H ,Song, H ,Rao, C ,et al. Accuracy analysis of centroid calculated by a modified center detection algorithm for Shack-Hartmann wavefront sensor[J]. OPTICS COMMUNICATIONS,2008,281(4):750-755 FEB 15.