基于电子束扫描阵列微焦点射线源的倒置结构Micro-CT成像研究  

Imaging Property of Inverse Geometry Micro-CT with Micro Multi-focus X-ray Source Based on Electron Beam Scanning

作　　者：周日峰 唐杰[1,2] 胡小龙[1,2] 谢东洋[1,2] 刘瑜川 ZHOU Rifeng;TANG Jie;HU Xiaolong;XIE Dongyang;LIU Yuchuan(Engineering Research Center of Industrial CT Nondestructive Testing of Ministry of Education,Chongqing 400044,China;ICT Research Center,Key Lab of Optoelectronic Technology and Systems,Ministry of Education,Chongqing University,Chongqing 400044,China;State Key Laboratory of Mechanical Transmission,Chongqing University,Chongqing 400044,China)

机构地区：[1]工业CT无损检测教育部工程研究中心,重庆400044 [2]重庆大学光电技术及系统教育部重点实验室ICT研究中心,重庆400044 [3]重庆大学机械传动国家重点实验室,重庆400044

出　　处：《原子能科学技术》2021年第12期2374-2381,共8页Atomic Energy Science and Technology

基　　金：国家自然科学基金重大科研仪器研制项目(11827809);国家重大科学仪器设备开发专项(2013YQ030629)。

摘　　要：倒置几何结构CT成像系统理论上具有扫描视场大、图像信噪比好、锥束伪影小等优点,但其多焦点、稀疏角的扫描模式亦会带来投影数据截断、稀疏和局部数据冗余等问题。本文利用电子束扫描阵列微焦点射线源和高分辨率小面积探测器等构建了一种新型高分辨率、大视场的倒置几何结构Micro-CT实验系统(IG-Micro-CT)。针对该系统多焦点、稀疏角扫描模式下的投影数据截断和稀疏等特点,提出一种图像先验约束的全变分正则化SART迭代CT图像重建算法。首先通过仿真实验对图像重建算法进行了验证,并对阵列微焦点数量、旋转扫描分度数量等扫描参数进行优化,最后在IG-Micro-CT实验系统上获得了高分辨的Micro-CT测试图像。实验结果表明,本文提出的算法适用于IG-Micro-CT系统,解决了投影数据截断、稀疏采样和局部数据冗余带来的条状等伪影问题,并验证了IG-Micro-CT这种新型成像方式的可行性。In theory,inverse geometry CT has the advantages of larger scanning field,higher signal-to-noise ratio and fewer cone beam artifacts.However,in the multi-focus and sparse angle scanning mode,the projection data also has some problems such as data truncation,sparseness and local redundancy.An inverse geometry Micro-CT experimental system(IG-Micro-CT)with high resolution and large field of view was constructed by using electron beam scanning array micro multi-focal X-ray source and small area high-resolution detector.In view of the characteristics of multi-focal,sparse angle scanning mode projection data truncation and sparseness,a relative prior image guided SART iterative CT image reconstruction algorithm was proposed.Firstly,the algorithm was verified by simulation experiments,and the scanning parameters such as the number of ray source focus were optimized.Finally,high-resolution Micro-CT test images were obtained on the IG-Micro-CT experimental system.The experimental results show that the proposed algorithm can solve the problems of strip and truncation artifacts caused by projection data truncation,sparse sampling and local data redundancy.Besides,the feasibility of this new imaging method of IG-Micro-CT was verified,which lays a foundation for the practical application of IG-Micro-CT system.

关 键 词：MICRO-CT 倒置几何结构CT 电子束扫描阵列微焦点射线源 CT图像重建 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]