Abstract
The spatial resolution and the relative density resolution are the two most critical indicators in CT system. The method recommended in the ASTM E1695-95 and GJB 5311-2004 is only suitable to the fan-beam CT system. In this paper, for industrial cone-beam micro CT system, we will adopt the edge response function (ERF) created by the step edges of a steel ball to measure the system 3D PSF and MTF. To describe the contrast discrimination function more accurately, we will first propose to extend the two-dimensional measurement region to the three-dimensional space. Our experimental spatial resolution is (55.56±0.56) lp/mm and the relative density resolution is 1% within 300 μm×300 μm×300 μm according to the 3σ rule.