Method to control point spread function of an image

摘要

A method of controlling the point spread function of an image projected with said image being diffused by a filter; said point spread function is a result of the application of spatial filter(s) on said image; with said control of the point spread function effected by varying the distance between such image and said spatial filter(s) and varying the bidirectional scattering transmission function of the spatial filter(s). Said spatial filter may be a holographic diffuser, which by method of manufacture has a ell defined bi-directional scattering transmission spread function. Control of said spread function is particularly useful to maintain image quality while abating moiré interference in situations where two periodic patterns are layered causing moiré interference.