中文摘要：

计算机层析成像（CL）系统对于扁平状物体的检测具有独特的优势,几何参数标定是CL系统获得高质量图像的重要步骤。现有CL系统几何参数标定方法仅能标定部分几何参数,难以一次完成所有几何参数的标定。借鉴计算机断层成像（CT）系统几何参数标定方法,提出了一种高精度的迭代标定方法,利用简单体模快速标定CL系统的所有几何参数。对CT系统几何参数标定方法用于CL系统的有效性进行分析,确定对CT系统几何参数标定方法敏感的CL系统几何参数;根据CL系统投影几何关系,构建新的反映CL实际系统与理想系统间误差的非线性最小二乘目标函数,利用迭代法不断优化敏感参数和其他关键参数。实验结果表明,本文方法能够有效标定CL系统所有几何参数,敏感参数以及受敏感参数影响的其他几何参数标定精度均有明显提升。利用已标定的几何参数重建三维Shepp-Logan体模和印刷电路板体模,重建图像中没有几何伪影,验证了算法的有效性。

英文摘要：

Computed laminography（CL）has a unique advantage for the inspection of flat objects.Geometric parameter calibration of the CL system is an important step in acquiring high quality reconstruction images.However,the existing calibration methods for the CL system can not solve all parameters in one calibration.A novel iterative geometric parameter calibration method based on the classical method for computed tomography（CT）is proposed,which can calibrate all geometric parameters by using a simple phantom.Firstly,the CT calibration method is applied to the CL system to determine the parameter sensitive to the CT method.Secondly,a new non-linear least square cost function according to the error between the practical system and the ideal system is presented,thus the sensitive parameter and other parameters are optimized by the iterative method.Experimental results prove that the proposed method can accurately calibrate all the geometric parameters,and the precision of the sensitive parameter as well as those affected by the sensitive parameter are all significantly improved.Meanwhile,the corrected geometric parameters are used to reconstruct the Shepp-Logan phantom and the printed circuit board phantom,and there are no geometric artifacts in the reconstructed images,which prove the validity of the proposed method.