1. A method comprising: obtaining projective transformations corresponding to images to be joined together; calculating, by a computer including at least one processor and at least one memory device, distortion information based on data corresponding to the images; selecting, based on the calculated distortion information, one of the images to be a reference image for remaining ones of the images; setting a projective transformation of the reference image according to a group transform; correcting remaining projective transformations of the remaining images in accordance with the setting the projective transformation of the reference image; and making the images and the corrected remaining projective transformations available for further processing and output.