1. A tomographic apparatus for testing an object material which is either a reference sample or an inspection sample, comprising: scanner means for generating and scanning a radiation beam within a given plane in which said object material is located, and providing a scanner output containing radiation absorption information of a given slice of said object material; reconstruction means, coupled to said scanner means, for reconstructing a tomographic image from said scanner output to provide reference image data and inspection image data, for storing said reference image data, and for providing tomographic image data corresponding to the stored reference image data and said inspection image data wherein said reference image data lacks information corresponding to said inspection image data, said inspection image data lacks information corresponding to said reference image data, and said tomographic image data corresponds to the combination of said reference image data and said inspection image data; and a display means coupled to said reconstruction means for displaying a tomographic image of said inspection sample in accordance with said tomographic image data.