板状物成像方法研究

Research on Imaging Method of Flat Plate

在工业CT成像应用中,板状物结构件受形状、结构、组分等特征的限制,使得射线能量与有效厚度不匹配,常规的扫描方式易使投影数据缺失,投影数据完备性较差。为此,讨论了一种基于倾斜圆扫描轨迹和代数迭代重建技术的CT成像模式。首先,在倾斜圆轨迹的基础上进行投影几何关系建模,结合空间几何知识完成投影矩阵的刻画;其次,基于迭代重建算法对轨迹的无约束化,研究任意扫描轨迹的迭代重建算法;最后通过板状物成像仿真实验,验证了算法的正确性和可行性。对于板状物结构件,该方法相对于传统的圆轨迹扫描,投影数据更完备,CT重建质量高。

In the application of industrial CT imaging,the X-ray energy mismatch to the effective thickness and traditional scanning is difficult to preserve the data integrity of projection due to the limit of tabular-structure＇s shape,structure and so on.In order to make up for the deficiency of projection data,a method based on the cone beam inclined circle scanning and the algebraic reconstruction technique（ART） is proposed.First of all,in the base of inclined circle scanning,the knowledge of analytic geometry with the projection is combined to obtain the projection matrix.The second,the iterative reconstruction algorithm is not binding to some trajectory,so we study the iterative reconstruction algorithm along a general scanning trajectory.Finally,according to the numerical simulation of tabular-structure the correctness and feasibility of the algorithm is verified.For the tabular-structure,compared to the traditional circle scanning,this method is better for preserving the data integrity of projection and improving the quality of reconstructed image.