VERFAHREN ZUR GEWINNUNG VON INFORMATION UEBER DIE GRENZE EINES OBJEKTES BEI DER COMPUTERISIERTEN TOMOGRAPHIE MIT BEGRENZTEM WINKEL

摘要

A method is developed to construct the convex hull of an object in limited-angle x-ray computerized tomography. The convex hull is the smallest convex region containing the object, and therefore it can serve as a prior information on the object exterior boundary in reconstructing the object by an iterative limited-angle reconstruction procedure. The convex hull is the same as the exterior boundary of many convex objects and is a good approximation if the shape is not too concave. Greater accuracy is achieved by doing curve fitting near the edges of the x-ray projection data to determine the end points, and performing a low energy x-ray exposure at every scan angle in addition to the usual CT energy one. Over-attenuated x-ray data has utility in constructing the convex hull.