1. A tomographic method comprising the steps of: (a) using a radiation source to take a series of co-planar images of a subject from different, predetermined locations, (b) forming first order clarified images for each of a plurality of parallel planes through the subject by shifting and superimposing the co-planar images for each such plane to cause all of the corresponding points in each such plane to be approximately coincident, (c) for each one of a selected number of planes, forming smeared, first order clarified images by reproducing a predetermined number of times the first order clarified image for the selected plane, and superimposing each of said reproduced first order clarified images shifted in different positions in said selected plane as a function of the distance between the radiation source and said selected plane, the distance between said selected plane and the co-planar images, the same distances but with respect to a particular plane of interest, and the distances traveled by the radiation source in producing the series of co-planar images, and (d) multiplying the smeared images by appropriate coefficients and then subtracting them from the first order clarified image of said particular plane of interest to form a second order clarified image of the particular plane of interest.