Technique for simulating film grain using frequency filtering

Abstract From the Canadian patent

Simulation of film grain in an image can occur by compressing a video image then transmitting compressed video together with a message containing at least one parameter indicative of the original film grain to a decoder, and , restoring the original grainy appearance of images by having the decoder simulating film grain based on the content of the film grain message. To improve efficiency, one or more parameters of film grain information undergo scaling in accordance with a target pixel block size for pixel blocks in the image. Such scaling allows for the use of conventional circuitry for performing block-based operations in connection with the film grain simulation.