1. An image processing method, comprising: a detecting step detecting a characteristic area for each of three or more shot images having a common graphic pattern in part thereof, the pixels in the region of one shot image specified by its corresponding characteristic area being significantly different from the pixels in the corresponding region of each of the other shot images; a generation step generating a distribution map based on the detected characteristic areas and a threshold such that each pixel of the distribution map has a value that identifies one of the shot images or is a particular value; a filtering step performing filter processing on the distribution map by replacing a pixel value of a focused pixel with a most common pixel value within a determined neighborhood of said focused pixel if the most common pixel value is not the same as the particular value and replacing the pixel value of the focused pixel with a second most common pixel value in said neighborhood otherwise; and a combining step extracting a partial image from each of the three or more shot images according to the distribution map generated by performing the filter processing and combining these partial images into one image.