A reduced order point spread function model for physical optical systems

A reduced order point spread function (PSF) model for physical optical systems is developed for the space variant (SV) PSF of undercorrected imaging optical systems with a rectangular aperture. The model accommodates broadening and shifting of the central lobe as field angle increases. Diffraction-based PSF models exhibit these effects. The model is adapted to PSFs developed from diffraction theory using an adaptive system with gradient descent parameter adjustment. Consequently, the model is useful for applying certain SV digital image restoration methods because it significantly reduces the memory required to store PSF sample functions. Data is presented that confirms the accuracy and the computational advantage of the model by quantifying its adaptation to several physical PSFs, over a range of field angles, arising from a simple imaging optical system.