一种基于正弦图的工业CT系统转台旋转中心自动确定方法  

Method for Automatic Determination of Center of Rotation in Industrial Computed Tomography Systems Based on Sinogram

作　　者：李保磊[1] 傅健[1] 黄巧珍[1] 陈浩[2] 王远[2] 

机构地区：[1]北京航空航天大学机械工程及自动化学院,北京100191 [2]中国工程物理研究院应用电子学研究所,四川绵阳621900

出　　处：《航空学报》2009年第7期1341-1345,共5页Acta Aeronautica et Astronautica Sinica

基　　金：航空科学基金(20070951013);航天科技创新基金(CASC0410);北京市科技新星基金(2005A14)

摘　　要：构建一个工业CT成像系统,转台旋转中心的确定是非常关键的步骤,其定位误差会引起CT图像上的伪影。本文在详细分析了现存旋转中心确定方法不足的基础上,提出了一种新方法,该方法利用隐含在正弦图中的对称投影信息,并根据经过旋转中心的射线束在两个对称投影视角下透过的物体路径相同这一规律来定位旋转中心。相对现有算法,该方法适用于射线源与旋转中心的连线不严格垂直于探测器的情形,无需使用模体,亦无需知晓任何几何参数,实时且基本不受随机噪声影响。实验数据验证了该方法的有效性。For setting up an industrial computed tomography （ICT） imaging system, the determination of the center of the rotation （COR） of the rotating table is of critical importance as errors of the COR can lead to artifacts in CT images. In this article, the current methods for COR determination are described and their disad- vantages are analyzed. Based on the analysis, a novel method is put forward. The proposed algorithm is based on the symmetry projection information implied in the sinogram and the following law： in relation to the two symmetrical projection views, the transmission path of the X-ray which passes through the COR of the rotating table is the same. Compared with the current methods, the proposed algorithm is applicable for the situation in which the tie line of the X-ray source and the COR is not strictly perpendicular to the detector. It does not need any phantom or geometry parameters, and is hardly affected by random noise. The feasibility of the method is validated by the experiment data.

关 键 词：工业CT 成像系统 旋转中心 正弦图 对称投影 无损检测 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]