An image acquisition unit acquires first and second radiographic images acquired by irradiating a first radiation detector and a second radiation detector which overlaps the first radiation detector so as to deviate from the first radiation detector by a half pixel with radiation which has been emitted from a radiation source and transmitted through an object. A corresponding positional relationship acquisition unit acquires a corresponding positional relationship between the position of pixels of the first radiographic image and the position of pixels of the second radiographic image. A resolution enhancement unit estimates a pixel value corresponding to a position between the pixels of the first radiographic image, on the basis of the corresponding positional relationship, a pixel value of the first radiographic image, and a pixel value of the second radiographic image, and generates a processed radiographic image having a higher resolution than the first and second radiographic images.
