1. An image processing method, implemented in a calculator, the method comprising steps of: applying a process by group of pixels to an original image to obtain a final image signal, for each group of pixels, calculating a cumulative sum of value or position differences of the pixels of the group of pixels, for each group of pixels, allocating in the final image signal a pixel position of the group of pixels to each pixel value of the group of pixels, so as to minimize the cumulative sum of differences calculated for the group of pixels, and/or for each group of pixels, determining a filtering intensity according to the cumulative sum of differences calculated for the group of pixels, and applying to the group of pixels a filtering having the filtering intensity.