针孔相机全场X射线荧光成像的模拟研究  

Simulation study of full-field X-ray fluorescence imaging with a pinhole camera

作　　者：何泽[1] 黄宁[1] 王鹏[1] 陈子晗 彭博[1] He Ze;Huang Ning;Wang Peng;Cheng Zihan;Peng Bo(Key Laboratory of Radiation Physics and Technology of the Ministry of Education,Institute of Nuclear Science and Technology,Sichuan University,Chengdu 610064,China)

机构地区：[1]四川大学原子核科学技术研究所,辐射物理与技术教育部重点实验室,成都610064

出　　处：《强激光与粒子束》2021年第11期180-188,共9页High Power Laser and Particle Beams

基　　金：四川省重大科技专项(2020ZDZX0004)。

摘　　要：为解决全场X射线荧光(XRF)成像中针孔形状和尺寸的选取问题,采用Geant4软件,模拟了6种不同类型针孔和4种不同的针孔孔径,分析了这些参数对点扩散函数和调制传递函数的影响;模拟了不同能量X射线荧光平面源的成像过程,并用均值滤波和Richardson迭代法对图像进行处理,分析了图像处理的效果。模拟结果表明:对于能量小于20 keV的荧光X射线,双锥孔结合直孔模型的点扩散函数尖锐性和等晕性更好,调制传递函数的截止频率更大,空间分辨更好,更适合做全场XRF成像的针孔;均值滤波结合Richardson迭代法的图像处理算法对全场XRF图像处理的效果较好。To solve the problem of selecting shape and size of the pinhole in the full-field X-ray fluorescence(XRF)imaging,the Geant4 Monte Carlo simulation software was used to simulate pinholes of 6 different types and 4 different diameters.The effects of the parameters on the spatial resolution which referred to the point spread function and the modulation transfer function were analyzed.The imaging process of different energy fluorescence X-ray plane sources is simulated,and the performance of image processing was analyzed by mean filter and the Richardson iteration method.The simulation results show that the pinhole model of the double conical-hole combined with the straight-hole has better sharpness and isoplanatism of the point spread function,a higher cut-off frequency of modulation transmission function,and better spatial resolution for X-ray of the energy less than 20 keV,which meant it is more suitable for full-field XRF imaging;the algorithm of mean filtering combined with the Richardson iteration performs better in full-field XRF image processing.

关 键 词：全场XRF Geant4模拟 空间分辨 图像处理 

分 类 号：O657.34[理学—分析化学]