Technique for bit-accurate film grain simulation
View Patent ↗The simulation of film grain in an image makes use of parameters contained in a Supplemental Enhancement Information (SEI) message that accompanies the image upon transmission. The SEI message specifies film grain simulation parameters such as the film simulation model, the blending mode, and color space.
1. In combination with a film grain generation apparatus, a method for simulating bit accurate film grain in an image block, comprising the steps of:
computing, via the film grain generation apparatus, the average of the pixel values within the image block;
randomly selecting, as a function of the average value of the image block, a block of bit accurate film grain from among a pool of previously established blocks of bit accurate film grain via the film grain generation apparatus.
2. The method according to claim 1 further including the step of blending, via the film grain generation apparatus, each pixel in the selected film grain block with a corresponding pixel in the image block.
3. The method according to claim 2 further comprising the step of populating the look-up table, via the film grain generation apparatus, in advance of film grain simulation with random numbers generated by a random number generator.
4. The method according to claim 1 wherein the step of randomly selecting a film grain block further includes the step of accessing a look up table containing random numbers to obtain a random number via the film grain generation apparatus.
5. Apparatus for simulating bit accurate film grain in an image block, comprising:
means for computing the average of the pixel values within the block;
means for randomly selecting, as a function of the average value of the image block, a block of bit accurate film grain from among a pool of previously established blocks of bit accurate film grain; and
means for blending each pixel in the selected block of bit accurate film grain with a corresponding pixel in the image block.
6. The apparatus according to claim 5 wherein the means for randomly selecting a film grain block further comprises a look up table containing random numbers.