一种新的三维CT扫描系统投影坐标原点的高精度测量方法  

A New Method of Measuring the Origin of the 3D-CT Scanning System Projection Coordinates with High Accuracy

作　　者：杨民[1] 孙晶晶[1] 王钢[1] 吴文晋[1] 

机构地区：[1]北京航空航天大学机械工程及自动化学院,北京100083

出　　处：《上海交通大学学报》2008年第4期590-593,598,共5页Journal of Shanghai Jiaotong University

基　　金：国家自然科学基金(60402042);航天科技创新基金(CASC0410);北京市科技新星基金(2005A14)资助项目

摘　　要：针对实际的三维CT扫描成像系统射线源焦点和探测器成像面的位置不能直接测量的问题,提出了一种简单易行的投影坐标系原点位置精确测量方法.利用双圆目标体二次成像获得的DR(Digital Radiography)图像,配合图像、图形处理方法和最小二乘拟合技术求取不同成像位置下的目标体圆心投影坐标,然后求解方程组得到投影坐标系的原点坐标.实验结果表明,所提出方法的测量精度达到了实际扫描系统的重建要求,并且实现简单、具有较强的抗噪能力.In the three dimensional computed tomography imaging system, it is impossible to measure the position of the X-ray focus and imaging plane of the detector by direct means. A simple and feasible method to measure the origin of the projection coordinates with high accuracy is proposed. Through acquiring the DR（digital radiography） images of the double-circled object at two imaging positions, the image and graphics processing methods and the least square fitting method are used so as to get the coordinates of the two circles＇ projection center. Then through solving equations, the value of the origin of the projection coordinates is finally obtained. The experimental results prove that the accuracy of this method can satisfy the requirements of the practical scanning system, meanwhile it is easy to realize and of high anti-noise ability.

关 键 词：三维计算机断层扫描 投影坐标原点 最小二乘拟合 射线检测 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]