基于散射校正板和ADMM算法的锥束CT散射校正  

CT Scatter Correction Based on Beam-hole Array and ADMM Algorithm

作　　者：赵浩翔 赵晓杰 陈平[1,2] 魏交统 ZHAO Haoxiang;ZHAO Xiaojie;CHEN Ping;WEI Jiaotong(College of Information and Communication Engineering,North University of China,Taiyuan 030051,China;Shanxi Key Laboratory of Information Detection and Processing,Taiyuan 030051,China)

机构地区：[1]中北大学信息与通信工程学院,太原030051 [2]信息探测与处理山西省重点实验室,太原030051

出　　处：《CT理论与应用研究(中英文)》2025年第2期225-234,共10页Computerized Tomography Theory and Applications

基　　金：国家自然科学基金(面向黄土质煤岩层孔裂隙结构动态表征的宽视场高分辨动态CT成像研究(U23A20285);面向航发叶片残芯影像表征的X射线多谱CT成像方法研究(62301508);基于X射线投影图像盲分离的预设能量CT成像算法研究(62201520));国家重点研发计划(半导体器件封装质量智能检测关键技术研究与应用示范(2023YFE0205800));山西省自然科学基金(面向碳封存的煤岩盖层孔隙结构X射线多谱CT多尺度表征方法(202203021222052))。

摘　　要：在锥束计算机断层扫描(CBCT)系统中,散射信号的存在会导致图像产生伪影,影响图像质量,降低图像的对比度和信噪比。为了精确估计散射信号以抑制散射伪影,提出一种基于散射校正板和交替方向乘子法(ADMM)的锥束CT散射校正方法。基于射束孔阵列(BHA)散射校正板的校正原理,在待测工件和探测器之间添加散射校正板对工件进行扫描,获取投影数据并计算射束孔中心处散射信号。同时,结合压缩感知理论,建立L1范数约束模型,采用交替方向乘子法获取完整散射场分布,并通过扫描角度插值算法,减少全角度散射场重构所需时间。去除散射后进行重建即可得散射校正后的CT图像。通过数据分析对重建切片的图像质量进行评估,分析结果表明,基于BHA散射校正板的散射校正方法有效提升图像对比度,减少散射伪影,改进的散射信号重构方法进一步提高散射信号的准确性,散射抑制效果更为明显。同时,使用扫描角度插值算法提高散射场重构效率;采用BHA与ADMM相结合的方法能够更好的去除散射,图像质量得到进一步改善。In cone-beam computed tomography(CT) systems,scatter signals can result in artifacts in images,thus adversely affecting image quality by reducing the contrast and signal-to-noise ratio.To accurately estimate and suppress scatter artifacts,a new scattercorrection method for cone-beam CT based on a beam-hole array(BHA) scatter-correction plate and the alternating direction method of multipliers(ADMM) are proposed.Based on the correction principle of the BHA scatter-correction plate,the plate is placed between the object under test and the detector during scanning.This setup captures projection data and computes scatter signals at the centers of the beam holes.Simultaneously,by incorporating the theory of compressed sensing,an L1-norm constrained model is established,and the ADMM is utilized to obtain a complete scatter-field distribution.Using an interpolation algorithm to scan angles reduces the time required for a full-angle reconstruction of the scatter field.Post-scatter removal and reconstruction yield scattercorrected CT images.Data analysis of the reconstructed slices reveals the image quality,which indicates that the scatter-correction method based on the BHA plate effectively enhances the image contrast and reduces scatter artifacts.The improved scatter-signal reconstruction method further increases the accuracy of scatter-signal estimation,thus rendering scatter suppression more pronounced.Furthermore,using scanning-angle interpolation algorithms improves the efficiency of scatter-field reconstruction.The combined use of BHA and ADMM provides better scatter removal and further improvement in image quality.

关 键 词：CT 散射校正板 散射校正 ADMM算法 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术] O242[自动化与计算机技术—计算机科学与技术]