变电压CT成像中角度间扫描电压预测方法研究  

Research on the Prediction Method of Inter⁃Angle Scanning Voltage in Variable Voltage CT Imaging

作　　者：魏交统 WEI Jiaotong(School of Information and Communication Engineering,North University of China,Taiyuan 030051,China)

机构地区：[1]中北大学信息与通信工程学院,山西太原030051

出　　处：《测试技术学报》2024年第5期481-486,共6页Journal of Test and Measurement Technology

基　　金：国家自然科学基金资助项目(62201520,62122070,62301508,U23A20285);国家重点研发计划课题(2023YFE0205800);山西省自然科学基金资助项目(202203021222052,202303021222096,202303021222095)。

摘　　要：复杂结构件在CT成像时,不同投影角度等效厚度差异较大,需要匹配不同透照电压。因此,投影扫描中需要进行变电压成像,这需要对角度间的透照电压进行预测。对此,提出了一种适用于变电压CT成像的角度间扫描电压预测方法。利用负指数函数描述等效衰减系数与电压的关系,代入基于等效衰减系数表示的不同电压下X射线透过率关系式中,得到不同透过率对应电压之间的经验公式。在角度间电压预测中,不断更新公式中参数。对铝楔形块实验,与文献方法相比,所有测试点电压预测的最大相对误差由6.24%下降到3.91%。对铝模体进行了变电压扫描CT成像实验,验证了预测方法的可行性。实验结果表明,提出的电压预测方法可用于变电压CT成像中的角度间扫描电压预测。For CT imaging of a complex structural part,the equivalent thicknesses of different projection angles have large differences.So matched voltages are different for different projection angles.Variable voltage scanning is essential in the CT imaging of complex structural parts.A method for predicting scan-ning voltages at different angles was proposed for variable voltage CT imaging.The negative exponential function was used to describe the change of the equivalent attenuation coefficient with the imaging volt-age.It is substituted into the function relationship of X-ray transmission rates of different voltages repre-sented by equivalent attenuation coefficients.The empirical function relationship of different voltages with corresponding X-ray transmission rates was derived.The parameters were constantly updated for the func-tion relationship with projection angle change in scanning voltage prediction.In the experiment of alumi-num wedge block,compared with a method of literature,the max relative error of predicted voltage with the proposed method for all test points was decreased from 6.24%to 3.91%.The experiment of variable voltage CT imaging of aluminum phantom showed the effectiveness of the proposed method for scanning voltage prediction.From the experiments,the proposed method for scanning voltage prediction is suitable for the scanning voltage prediction of different angles in variable voltage CT imaging.

关 键 词：X射线成像 变电压 CT成像 透过率 扫描电压预测 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]