Patent ID: 7643696

Claim:
An image processing method for restricting granular noise present in photographic image data obtained by digitization of an image by a weighted average filtering operation, the method comprising the steps of: setting one target pixel after another from a group of pixels together constituting said photographic image data stored in a memory by target pixel setting section of image processing unit; calculating a difference value between a pixel value of said target pixel and each peripheral pixel present within a calculating area centering about said target pixel and used for the weighted average filtering operation by a difference value calculation section of said image processing unit; determining a weight coefficient for use in the weighted average filtering operation in accordance with said difference value by a weight coefficient determining section of said image processing unit; said weight coefficient having a defined range from 0 to 1, being set to 1 when said difference value is 0, being selected from a group of values wherein said weight coefficient is set to decrease monotonously from 1 with increasing absolute value of said difference value and then increase monotonously to 1 when said difference value is greater than 0 and smaller than a predetermined threshold value, and being set to 0 or being selected from a group of values wherein said weight coefficient is set to decrease monotonously from 1 with increasing absolute value of said difference value when absolute value of said difference value is equal to or greater than said threshold; obtaining a corrected pixel value for said target pixel by effecting the weighted average filtering operation with using weight coefficient by filtering operation section of said image processing unit; and storing said corrected pixel value in said memory by said image processing unit.