US Patent 7092016 Method and system for motion image digital processing

A method for digitally processing motion image signals comprises the steps of: (a) obtaining digital motion image signals that originated from a sequence of motion picture frames; (b) using a frame averaging technique to reduce noise in the digital motion image signals, thereby producing noise-processed motion image signals; and (c) producing output digital motion image signals by sharpening the noise-processed motion image signals with a sharpening filter designed in the spatial domain with a 2D kernel that increases the noise in order to provide a desired grain response.