Computer correction of projective distortions in dental radiographs.

Distortions in radiographic images caused by changes in shape and position of the film relative to the x-ray beam can result in registration artifacts which interfere with interpretation of subtracted images. A warping transformation is described which maps known points of reference in one image into homologous points in another. The corrected image pair can then be superimposed and subtracted with significantly-reduced differences in registration to facilitate the detection of localized changes of diagnostic interest.