A digital camera of the following type is known from Patent Reference #1. When creating a single image by superimposing a plurality of images that have been captured by multiple exposure, addition averaging processing is performed by, after having added together the image data for each shot, dividing the result by the number of shots.
Furthermore, with the digital camera of Patent Reference #1, a multiple exposure photographic image is created by superimposing a plurality of images, this multiple exposure photographic image is stored, and unnecessary original images are deleted.
Yet further, a technique of obtaining a multiple photography image in which a plurality of photographic images are superimposed is known from Patent Reference #2.    Patent Reference #1: Japanese Laid-Open Patent Publication 2003-69888.    Patent Reference #2: Japanese Laid-Open Patent Publication 2003-298925.
USPTO Backgrounds
USPTO Backgrounds