Systems and methods for computationally simulating an optical image are provided. The systems and methods generate a simulated scene having at least one variable optical property, compute an optical transfer function (OTF) via at least one computed phase screen, express the OTF as a sum of at least one separable OTF, convolve the at least one separable OTF with the simulated scene to simulate electromagnetic (EM) fields of the optical image, and compute image intensities of the optical image from the simulated EM fields of the optical image.