扇束CT探测器偏转的重建图像伪影校正  

The Correction of Fan-beam CT Image Artifacts Induced by Deflection of Linear-detectors

作　　者：李忠传 孟凡勇[2] 杨民[1] 

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]中国科学院过程工程研究所多相复杂系统国家重点实验室,北京100190

出　　处：《CT理论与应用研究（中英文）》2014年第2期237-248,共12页Computerized Tomography Theory and Applications

基　　金：国家自然科学基金(21106158;21376245;11275019;61077011);中国科学院战略性先导科技专项(XDA07080104);多相复杂系统国家重点实验室开放课题(MPCS-2011-D-03)

摘　　要：对于CT扇束扫描,射线源焦点与被测工件旋转中心的连线不垂直于探测器所在直线时,采用标准的滤波反投影重建算法重建出的图像会存在伪影,降低图像质量。本文基于经典滤波反投影重建算法理论,分析了此类伪影形成的原因,给出了利用投影原始数据(正弦图)计算校正算法所必需的几何参数的方法。本方法无需专用模体,不必进行二次扫描,方便、快捷并有效。计算机仿真及实验结果证明本方法的有效性。Artifacts will be introduced into the reconstruction for fan-beam CT system if the central X-ray is not perpendicular to the detector array, and the image quality will degrade consequently. In this study, the reasons for the formation of such artifacts are analyzed based on the classic theory of filtered back projection algorithm, and a novel method is proposed to calculate the geometric parameters necessary based on sinogram features. The image quality can be improved when we put these parameters into the revised algorithm. The newly proposed method requires no correction phantom, thus avoiding twice scan. Computer simulation and experimental results demonstrate that the method is easy, fast, and effective for practical utilization.

关 键 词：CT 探测器偏转 伪影 旋转中心 正弦图 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]