一种混合CBCT成像系统标定方法

发布时间：2018-04-12 10:56

本文选题：锥形束计算机体层摄影术 + 成像系统　；参考：《中国医学影像技术》2014年01期

【摘要】：目的建立一种混合锥形束CT(CBCT)成像系统标定方法,以提高CBCT成像系统参数标定精度,突破现有算法须已知标定模型中各小球相对中平面位置的限制。方法针对CBCT成像系统建立坐标系,推导光锥不同旋转角度下标定模型中小球中心空间坐标与其在投影图像中投影平面坐标之间的几何关系,提出解析+迭代混合标定方法。将标定模型置于CBCT成像系统中,获取各个旋转角度下的投影图像;提取投影图像中各小球投影的质心坐标,套用上述方法计算出标定参数。对小鼠标本模型进行相同扫描,采用已求标定参数用FDK算法进行3D重建。结果解析+迭代混合法对于成像系统参数D的标定精度较高;参数R的标定不直接受D的影响。结论解析+迭代混合法可提高部分成像参数的标定精度,且突破了须事先知晓小球相对于中平面的空间位置及受旋转半径影响较大的限制。
[Abstract]:Objective to establish a calibration method for CBCT imaging system with mixed conical beam in order to improve the calibration accuracy of the parameters, and to break through the limitation of the position of each sphere relative to the middle plane in the calibration model.Methods the coordinate system of CBCT imaging system was established and the geometric relationship between the space coordinates of the small and medium spherical center and the coordinate of the projection plane in the projection image was deduced under the different rotation angles of the optical cone. An analytical iterative mixed calibration method was proposed.The calibration model is placed in the CBCT imaging system to obtain the projection images at various rotation angles, and the centroid coordinates of each sphere projection in the projection image are extracted, and the calibration parameters are calculated using the above method.The mouse specimen model was scanned with the same scan, and the calibrated parameters were reconstructed by FDK algorithm.Results the accuracy of the analytical iterative mixing method for the calibration of the imaging system parameter D is high, and the calibration of the parameter R is not directly affected by D.Conclusion the analytical iterative mixing method can improve the calibration accuracy of some imaging parameters and break through the limitation of knowing the space position of the sphere relative to the middle plane and being greatly affected by the radius of rotation.
【作者单位】：上海理工大学医疗器械与食品学院;
【基金】：国家自然科学基金(61003119)
【分类号】：R318.6

【共引文献】