Abstract
Both X-ray image subtraction and CT are very useful for imaging inner structures of materials and components, and also for determination quantitatively the dimensions of those structures with fairly higher accuracy. In this paper we report the examples of sizing the diameters of pores in Si3N4 ceramics from the obtained images by both X-ray methods and compare them for discussion of the precision of those data. With the obtained data, both methods are confirmed to be very accurate to determine the sizes of inner structures.
