A Novel Designed Small Angle CT System based on Overlay Rotation

摘要

A small angle CT system is unable to scan a big object, which is larger than the field of view. In order to make full use of this kind of systems, several methods have been proposed to solve this problem, such as Half-Covered Helical CT, but additional scan process is also needed. This paper describes a novel designed rotation system to apply the small angle system for large object testing, whose scan process is as same as the conventional CT system. In this newly designed overlay rotation CT scanning system, two turntables are used to make up a two-degree-of-freedom system. These two turntables rotate at constant rotation rates and projection data is collected at the same time. In this paper, new projection data rebinning method is adopted and the reconstructed algorithm is also described. Numerical experiments are taken to test a simple prototype and verify the feasibility of this CT system. In conclusion, this novel designed overlay rotation CT system is effective to get enough projection data for reconstruction.