工业CT二维空间分辨力的校准方法

A Method of Calibrating Spatial Resolution of Industrial CT

工业CT的空间分辨力是指从CT图像中能够分辨特定的最小几何细节的能力,是评价一台工业CT系统测量能力的重要参数之一.为了提升工业CT的测量能力及成像质量,需要对其空间分辨力进行校准实验.针对这一问题设计出栅格形及交叉形分辨力线对卡,使用光刻工艺完成其研制过程,并基于此结合本底校正等图像处理方法进行了系统二维空间分辨力校准实验,通过调制传递函数MTF计算出实验系统的空间分辨力数值,验证了此方法可用于校准CT分辨力的实验意义.最后,对如何提升测量准确度的问题进行了探讨.

Spatial resolution of industrial CT indicates the ability to distinguish the minimum specific geometric details from CT images,which represents one of the most important parameters of measurement capability assessment of an industrial CT. Spatial resolution of industrial CT demands calibration in order to enhance the measurement capability and image quality of industrial CT. Regarding this problem,a set of grid and cross resolution line pairs cards were designed and manufactured via lithography,and on that basis,the 2 D system spatial resolution was calibrated with specific image processing methods such as background correction. Experimental results prove that this method can be applied to calibrating spatial resolution of industrial CT by calculation of system spatial resolution through modulation transfer function. At last,some issues on improving measurement accuracy were discussed.