三维显微CT扫描系统的X射线源焦点投影坐标测量方法  

Measurement Method of X-ray Focus Projection Coordinates of Three-Dimensional Micro-Computerized Tomography Scanning System

作　　者：杨民[1] 刘静华[1] 李保磊[1] 吴文晋[1] 王钢[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

出　　处：《光学学报》2009年第5期1275-1280,共6页Acta Optica Sinica

基　　金：国家自然科学基金(60872080);北京市教育委员会共建项目专项资助;航天科技创新基金(CASC0410);北京市科技新星基金(2005A14)资助课题

摘　　要：针对实际的三维显微CT成像系统射线源焦点和探测器成像面位置不能直接测量的问题,提出了一种简单易行的射线源焦点投影坐标精确测量方法。基于球体在锥束射线场中的投影为椭圆的原理,利用双球目标体成像获得的数字射线投影图像,配合图像、图形处理方法和最小二乘拟合技术求取二椭圆的长轴交点,该点坐标即为射线源焦点的投影坐标。实验结果表明,所提出方法的测量精度达到了实际显微CT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 micro-computerized tomography scanning system, it is impossible to measure the positions of the X-ray focus and imaging plane of the detector by direct means. A simple and feasible method to measure the X-ray focus projection coordinates with high accuracy is proposed. This method is based on the theory that the projection of the sphere object in the cone-beam field is an ellipse. Through acquiring the digital radiography images of the double sphere objects, the image and graphics processing methods and the least square fitting method are used to get the intersection point of the major axis of the two ellipses. The intersection point is also the X-ray focus projection on imaging plane of the detector. The experimental results prove that the accuracy of this method can satisfy the requirements of the practical micro-comptuterized tomography scanning system, and is easy to realize with high anti-noise ability.

关 键 词：图象处理 三维显微CT 焦点投影坐标 最小二乘拟合 X射线检测 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]