CT系统参数标定及成像问题研究

文章对CT系统参数标定及成像问题进行了系统的分析。首先建立了平面几何模型,由标定模板小圆的实际直径和投影长度不变建立对应关系,得到每个探测单元的间距e=0.2758mm。利用初始状态和射线与椭圆短轴垂直位置之间的几何关系,推导出初始状态射线与X轴负半轴的夹角为θ=60.1°,CT系统旋转中心坐标O'(-9.2070,6.0154)。由CT系统初始状态和终止状态模板椭圆的投影长度相等,得到CT系统180次旋转了180°,则每一次旋转1°,从而得到CT系统使用的X射线的180个方向。

In this paper, the parameters calibration and imaging of CT system are systematically analyzed. Firstly, the plane ge-ometry model is established, and the corresponding relationship between the actual diameter and projection length of the small circle of the calibration template is established, and the e=0.2758mm between each detection unit is obtained. Based on the geometric rela- tionship between the initial state and the vertical position of the ray and the short axis of the ellipse, the angle between the initial state ray and the negative half axis of the X axis is 0=60.1° CT, the rotation center coordinate of the CT system （-9.2070, 6.0154）. The projection length of the initial state and the terminal state template ellipse of CT system is equal, the 180 times of rotation of the CT system make 180., the rotation of each time is 1., and the 180 directions of X ray used in CT system are obtained.