一种新的TR层析扫描投影重排算法  

A New Method of Rebinning Projections for TR Tomographic Scanning

作　　者：孙亮[1] 籍雁翔 宋鑫 杨民[1] SUN Liang;JI Yanxiang;SONG Xin;YANG Min(School of Mechanical Engineering &Automation,Beihang University Beijing 100191,China)

机构地区：[1]北京航空航天大学机械工程及自动化学院

出　　处：《航空制造技术》2019年第14期76-82,共7页Aeronautical Manufacturing Technology

基　　金：国家重大科学仪器设备开发专项(2014YQ240445);装备预先研究项目(41423030512)

摘　　要：TR层析扫描可对超出射束范围的大尺寸构件进行检测,在工业CT领域有着重要的应用。目前使用的一种重建方法是在忽略扇角的影响下,将TR扫描正弦图直接重排成标准平行束正弦图,然后使用平行束的重建方法进行重建,这样导致重建图像存在一定误差。提出一种新的重排算法,通过坐标转换和插值计算,得到平行束正弦图中的各采样点在TR扫描正弦图中对应的映射点坐标及灰度信息,进而得到完整的平行束正弦图。通过仿真和试验,发现应用新算法得到的正弦图和重建图像均消除了边缘不光滑和伪影现象。新的重排算法能够消除现有重排算法的误差,使得TR扫描方法在扇束角较大时也能实现正确CT重建。TR tomographic scanning can detect large-scale components beyond the beam range,and has important applications in the field of ICT.One of the current reconstruction methods is to directly rebinding TR scan sinogram into standard parallel-beam sinogram without considering the influence of sector angle,and then reconstruct them using parallel-beam reconstruction method,which results in some errors in the reconstructed images.In this paper,a new rebinding algorithm is proposed.Through the coordinate transformation and interpolation calculation,the coordinates and gray scale information of the corresponding mapping points of the sampling points in the parallel sinogram are obtained in the TR scan sinogram.In this way,a complete parallel beam sinogram is obtained.Through simulations and experiments,it is found that the edge smoothness and artifacts are eliminated in both the sinogram and the reconstructed image obtained by the improved algorithm.The new rebinding algorithm can eliminate the errors of the existing rebinding algorithm.The TR scanning method can also achieve correct CT reconstruction when the fan beam angle is large.

关 键 词：TR层析扫描 正弦图 投影重排 坐标转换 CT重建 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]