1. An image processing apparatus comprising: a storage unit comprising a structure that stores corresponding information, wherein the corresponding information is previously generated as follows: taking a dynamic image of an object that comprises a total number n of sequential frame images F n , wherein n =2,3,. .. n; generating a calculation middle image formed from a plurality of the frame images; integrating the calculation middle image into a single calculation result image by obtaining for each pixel of the calculation middle image a statistic value in a pixel region of each pixel and then mapping the statistic values into a corresponding pixel of the single calculation result image; and generating the corresponding information by determining information that corresponds each pixel region of the single calculation result image to one of the frame images F n or the calculation middle image of which a pixel value is employed in the mapping of the statistic value corresponding to the pixel region; a specification unit comprising a structure that specifies one of the pixel regions in the single calculation result image; and a determination unit comprising a structure that determines an output image based on the corresponding information corresponding to the pixel region specified by the specification unit.