CT系统安装时往往存在误差，从而影响成像质量，因此需要对安装好的CT系统进行参数标定，即借助于已知结构的样品（称为模板）标定CT系统的参数，并据此对未知结构的样品进行成像。(CT system installation errors often occur, thus affecting the image quality, therefore need calibration of CT system installed parameters, which is based on the known structure of the sample (called template) calibration of CT system, and the sample of unknown structure based on imaging.)