CAJ | 학술논문

为了解决锥束CT（ computed tomography ）成像系统中几何参数不能直接测量的问题，提出了一种适用于螺旋扫描轨迹的几何参数标定方法。该方法根据金属钢球的投影轨迹与系统几何参数的关系，构建了仅依赖5个几何参数的非线性最小二乘模型。然后利用Levenberg-Marquardt （ L-M）算法求解该优化模型从而得到系统几何参数的最优解。该方法实现简单，校正体模仅需一个固定在有机玻璃内的金属钢球，而无需专用的校正体模，对校正体模的加工精度要求较低。计算机数值仿真和实际实验的结果表明，该方法具有较高的测量精度，能满足实际应用中高精度重建的需求。
위료해결추속CT（ computed tomography ）성상계통중궤하삼수불능직접측량적문제，제출료일충괄용우라선소묘궤적적궤하삼수표정방법。해방법근거금속강구적투영궤적여계통궤하삼수적관계，구건료부의뢰5개궤하삼수적비선성최소이승모형。연후이용Levenberg-Marquardt （ L-M）산법구해해우화모형종이득도계통궤하삼수적최우해。해방법실현간단，교정체모부수일개고정재유궤파리내적금속강구，이무수전용적교정체모，대교정체모적가공정도요구교저。계산궤수치방진화실제실험적결과표명，해방법구유교고적측량정도，능만족실제응용중고정도중건적수구。
In cone-beam CT imaging system , it is difficult to measure the geometry parameters in a direct way . We propose a novel method for misalignment estimation of cone -beam CT scanners using non -line least square estimation that does not rely on dedicated calibration phantoms .According to the relationship between projection of the metal ball and geometrical parameters , a nonlinear least square model is derived depending on 5 geometrical parameters .The Levenberg-Marquardt ( L-M) algorithm is applied to minimize the optimiza-tion problem .The method is easy to implement and the calibration phantom just need a metal ball in organic glass.Numerical simulation and real experiment results indicate that the method is with high measurement pre -cision and can satisfy the demand of high precision reconstruction in practical application .