Registration of digital subtraction peripheral angiography images

Computer algorithms for automatic translational registration are investigated. Sometimes patient movement is not simply translational (this often occurs in the foot, for example) requiring the mask frame to be warped. Two methods of warping are investigated: (1) segmented registration where the mask frame is segmented and each segment is registered; (2) subpixel warp where, for each pixel in the contrast frame, the nearest neighbors in the mask frame are searched for the best subpixel match. The study indicates that automatic registration is feasible for angiography images of the legs and can probably be done in a reasonable amount of time if special hardware is utilized. In all cases, results match those obtained by a human operator