基于斜孔散射校正板的锥束X射线CT散射校正方法  

Scattering correction method for cone-beam X-ray CT based on slanted-hole scattering correction plate

作　　者：郭成龙 倪培君[1] 齐子诚[1] 付康 Guo Chenglong;Ni Peijun;Qi Zicheng;Fu Kang(The Ningbo Branch of Ordnance Science Institute of China,Ningbo 315000,China)

机构地区：[1]中国兵器科学研究院(宁波分院),浙江宁波315000

出　　处：《强激光与粒子束》2024年第7期76-84,共9页High Power Laser and Particle Beams

基　　金：国家重点研发计划项目(2022YFB602500);国家高技术发展计划项目。

摘　　要：锥束X射线CT和二维扇束、平行束CT系统相比具有扫描速度快、射线利用率高、重建图像轴向分辨率和水平分辨率一致等优点,是当前工业CT技术发展的重点。然而,由于散射线的存在,其成像质量受到影响。为了减小散射线对图像质量的影响,提出一种新的基于斜孔散射校正板的散射校正方法,对该方法的原理和实现进行了深入的研究,通过获取原始扫描数据以及斜孔散射校正板后的扫描数据,利用插值和平滑处理的方法获得散射场数据。然后,通过将原始数据减去散射场数据后进行重建,即可得到无散射的CT图像。通过与光栅式散射校正板校正方法进行对比,结果表明,该方法应用于涡轮叶片的锥束CT扫描结果校正,典型区域(叶片内冷却通道及叶片内壁)对比度噪声比分别提升了14.2%和56.8%,而光栅式散射校正板校正后,同一位置对比度噪声比分别仅提升了5.6%和27.6%,验证了基于斜孔散射校正板散射校正方法的优越性。Compared with two-dimensional fan-beam and parallel-beam CT systems,cone-beam X-ray CT has advantages such as fast scanning speed,high X-ray utilization efficiency,consistent axial and horizontal resolution of reconstructed images,and is the focus of current industrial CT technology development.However,the imaging quality is affected by the presence of scattered radiation.To reduce the impact of scattered radiation on image quality,this paper proposes a new scatter correction method based on a slanted-hole scatter correction plate.The principle and implementation of this method are thoroughly investigated.By acquiring the raw scan data and the scan data after using the slanted-hole scatter correction plate,scatter field data is obtained using interpolation and smoothing techniques.Then,by subtracting the scatter field data from the original data and performing reconstruction,scatter-free CT images can be obtained.Compared with the grating-based scatter correction plate method,the results show that in cone-beam CT scans of turbine blades,the contrast-to-noise ratio of typical regions(the cooling channels within the blades and the inner walls of the blades)is improved by 14.2%and 56.8%respectively with the slanted-hole scatter correction plate method,whereas with the grating-based scatter correction plate method,the same positions only show an improvement of 5.6%and 27.6%respectively.This validates the superiority of the slanted-hole scatter correction plate scatter correction method.

关 键 词：X射线 锥束计算机断层扫描 散射校正 伪像 斜孔散射校正板 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]