DIGITAL IMAGE PROCESSING METHOD FOR DEGRAINING OF FILM IMAGES USING DISTANCE WEIGHTED AVERAGING OF TARGET PIXEL CODE VALUES

A method of digital image processing for degraining (smoothing) of images based on selected averaging of pixels in a neighborhood of pixels surrounding a target pixel to be recalculated. Improvement in the application of the selected average method to images of higher graininess such as might be obtained from higher speed films is achieved by weighting the difference in code values between each neighborhood pixel and the target pixel in accordance with a function that is related to physical distance between the neighborhood pixel and the target pixel. After all target pixels are recalculated using a selected fraction of pixel elements based on their distance weighted difference values, the process is iterated for each target pixel "n" number of times to achieve a desired relative code value of the target pixel to surrounding background pixel code values whereupon a final unweighted averaging operation is performed to achieve the final recalculated value of the target pixel.