针对扇束计算机层析成像(CT)不闭合的扫描数据，提出一种基于非线性优化模型的CT 几何伪影校正方法。该方法对标志物细丝与被测物体同时扫描，通过求解基于细丝断层投影数据的非线性优化模型，精确估计CT 系统的所有几何参数，进而校正包括扫描数据不闭合等几何参数误差引起的CT 图像伪影。仿真和实测数据验证结果表明，利用本方法可有效消除不闭合扫描数据引起的CT图像几何伪影。

For the unclosed scanning data of fan-beam computerized tomography (CT) , a correction method of geometrical artifacts based on nonlinear optimization model is proposed. The marked and measured objects are scanned by this method, and the geometric parameters of the CT system are precisely estimated by solving nonlinear optimization model which is based on the scanning data. The geometric artifacts caused by geometric parameters and the unclosed scanning data are corrected. Simulation and experimental results verify that the correction method effectively decrease the gometric artifacts of CT images for the unclosed CT data.