Transfer function estimation for spaceborne telescopes

The on-orbit calibration of the transfer function (TF) of a spaceborne optical telescope is of paramount importance for the restoration of its recorded images. The authors propose a novel method based on a physical modeling of the TF and on the automatic extraction from the image of sub-images containing appropriate patterns such as step functions. A least-square criterion is computed with all the extracted subimages, and is minimized as a function of the unknowns, which are the TF parameters and the step parameters. The simulation results validate the method and show a precise estimation of the full 2D TF