Angular-motion OTF model

A new model for the optical transfer function (OTF) of an imaging system during angular motion is presented. In the traditional analysis, the optic's point spread function (PSF) is assumed to be fixed and therefore, cascading the motion OTF with the optics' OTF is allowed. However, this method is found to be not accurate in the situation of varying viewing angle, which occurs during an angular motion of the imager. In angular motion conditions, the image is affected by space-variant wavefront aberrations, space-variant motion blur and space-variant defocus. The proposed model considers these effects and formulates a combined space-variant OTF obtained from the angle-dependent optics' PSF and the motion PSF which acts as a weighing function. Results of comparison between the new angular motion-dependent OTF and the traditional OTF show significant differences when the imaged object points are apart from the optical axis. To simplify the proposed OTF model, an efficient approximation is suggested and evaluated.