Detection and correction of geometrical distortion in x-ray fluoroscopic images.

Abstract The use of X-ray fluoroscopy with the image intensifier in radiological work has become routine in most departments of radiology in Britain. The problem of image distortion is rarely highlighted. A method has been devised to identify and correct distorted images using a computer programme after digitisation of the bony outline. The programme re-plots each digitised point, allows good correction of pin-cushion, barrel, trapezoidal and non-linear distortion and permits accurate measurements to be made from the images produced by a low X-ray exposure image intensifier. The method has been used successfully in a study of biplanar radiography of the moving shoulder girdle.