CT重建图像质量的优化算法  

Optimization algorithm of CT reconstruction image quality

作　　者：孙尔雁[1] 何高魁[1] 张向阳[1] 张思颖 SUN Eryan;HE Gaokui;ZHANG Xiangyang;ZHANG Siying(Nuclear Electronics and Detector Research Laboratory,China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院核电子学与探测器研究室,北京102413

出　　处：《无损检测》2025年第2期33-40,共8页Nondestructive Testing

基　　金：国家自然科学基金资助项目(U2341252)。

摘　　要：综述了CT成像算法的基本原理,基于计算机模拟试验的方法研究了Ramp滤波器和Shepp-Logan滤波器对成像质量的影响。鉴于Ramp滤波器高频增益过大,而Shepp-Logan滤波器又对高频增益抑制太大,致使边缘保持性指标过小,修正了Shepp-Logan滤波器,新修正的滤波器各方面评价指标都优于Shepp-Logan滤波器指标。此外,还研究了扫描投影数目与伪影产生的相关联情况。试验结果表明,对滤波后投影数据角积分公式的分析中,发现像素值是滤波后投影数据所在的笛卡尔坐标系中像素坐标(x,y)与原点(0,0)距离为直径的圆的线密度积分。This paper provided an overview of the basic principles of CT imaging algorithms.Based on computer simulation experiments,it investigated the effects of Ramp and Shepp-Logan filters on imaging quality.Given that the Ramp filter had excessive high-frequency gain and the Shepp-Logan filter suppressed high-frequency gain too much,resulting in a small edge preservation index,this paper proposed a modification to the Shepp-Logan filter.The newly modified filter performed better than the Shepp-Logan filter in all aspects of evaluation criteria.Additionally,the paper explored the correlation between the number of scan projections and the generation of artifacts.In the analysis of the integral formula for angle integration of filtered projection data,it was found that the pixel value was the line integral along the diameter of a circle with the Cartesian coordinate system of the filtered projection data at pixel coordinates(x,y)and the origin point(0,0).

关 键 词：CT成像 RADON变换 滤波反投影 Ramp滤波器 修正的Shepp-Logan滤波器 

分 类 号：TL99[核科学技术—核技术及应用] TG115.28[金属学及工艺—物理冶金]