The amount of time spent extracting linear noise components is reduced, when removing linear noise components from an image. A reduced image is generated, by reducing a radiation image in at least one of the vertical and horizontal directions. A linear noise image that represents linear noise components in the Y direction is generated, by extracting linear noise components from the reduced image. Thereafter, the generated linear noise image is enlarged to the image size of the original image the linear noise components are removed from the radiation image, employing the enlarged linear noise image.
