First ROI pixel values of a first region of interest 101 of an intensity distribution image 10, and second ROI pixel values of a second region of interest 102 of the intensity distribution image 10, are acquired. One of the first and second regions of interest is set to be at a position, or vicinity thereof, where a phase difference in the intensity modulation period within the intensity distribution image, with respect to the other region of interest, becomes À/2. Next, an elliptical locus obtained by plotting the first and second ROI pixel values for each intensity distribution image is determined. k angle region images are then acquired using the intensity distribution images corresponding to at least k angle regions that have been obtained by dividing the elliptical locus for each given angle. A radiographic image is then generated using the k angle region images. k is an integer of three or more.
