1. An image processing method comprising the steps of: defining a local region containing a pixel of interest in an original image; defining in a plurality of modes a pixel group consisting of a plurality of pixels containing said pixel of interest and a pixel group(s) consisting of a plurality of pixels not overlapping those in the former pixel group, in said region; selecting a pixel group mode from said defined plurality of pixel group modes which best fits a structure of said original image in said region; and producing an image using an average pixel value of said pixel group containing the pixel of interest in said selected pixel group mode, as a new pixel value for said pixel of interest.