In conventional apparatus with recorded images or video, in order to detect significant differences between two arbitrary images or detect points of video scene changes, the images and video have had to be selected by manual input operations and the differences have had to be confirmed by human sight, which required much time and effort. 
In order to solve these problems, methods for finding transitional scenes (referred to as scene changes below) in video have been proposed (see, for example, Patent Documents 1, 2, and 3).  Patent Document 1 discloses a method in which the sum of the absolute values of differences in histogram levels between two images that are successive with each other temporally is calculated in a video signal pre-processing apparatus in a stage preceding an encoder that performs encoding, and if the calculated sum exceeds a given threshold value, it is decided that a scene change has occurred.  Patent Document 2 discloses a method of determining scene changes by reading video data accumulated in storage media, such as HDDs.  Patent Document 3 shows a method of dividing image data, in which scene changes are to be detected, into blocks and detecting scene changes in each block. 
Patent Document 1: Japanese Patent Application
Publication No.  2004-282318 (p. 7, FIG.  2)
Patent Document 2: Japanese Patent Application
Publication No.  2002-064823 (p. 5, FIG.  1)
Patent Document 3: Japanese Patent Application
Publication No.  H5-284369 (p. 4, FIG.  1)