一种基于改进的多层法和GPU加速的透射电镜图像模拟算法和程序  

A GPU accelerated image simulation program based on improved multislice algorithm in (scanning) transmission electron microscopy

作　　者：明文全 陈江华 牛凤姣 沈若涵 何玉涛 陈志逵 MING Wen-quan;CHEN Jiang-hua;NIU Feng-jiao;SHEN Ruo-han;HE Yu-tao;CHEN Zhi-kui(Center for High-Resolution Electron Microscopy,College of Materials Science and Engineering,Hunan University,Changsha Hunan 410082,China)

机构地区：[1]湖南大学材料科学与工程学院高分辨电镜中心,湖南长沙410082

出　　处：《电子显微学报》2018年第5期427-435,共9页Journal of Chinese Electron Microscopy Society

基　　金：国家重大科研仪器研制项目(No.11427806);国家自然科学基金资助项目(No.51471067)

摘　　要：透射电镜高角环形暗场图像由于易于直观解释,已成为材料结构表征的重要手段。借助图像模拟技术对图像进行定量研究,可以获得材料中原子的三维排列和成分的信息。但由于高角环形暗场图像模拟计算量太大,其计算速度非常缓慢,限制了该技术的应用。本文提出一种改进的而且可用图像处理单元加速的图像模拟算法和程序,该算法通过使用图像处理硬件单元对矩阵进行并行计算,提高了图像模拟的速度。另外,通过缩小入射电子束矩阵的大小,可以在保证计算精度的同时减小图像的计算量。研究发现使用较小的入射电子束矩阵会在会聚束电子衍射低散射角区域引入明显误差,但对高角度散射的影响较小。针对低电压(扫描)透射电镜图像模拟,本算法采用了球面传播矫正多片层法以及全矫正多片层法,从而保证了低电压电镜图像模拟的精确计算。基于该改进的图像模拟计算方法,作者发展和编制了C++语言程序。该程序拥有简单易用的操作界面,也可以作为插件在Gatan Microscopy Suit图像处理程序中调用。High angle annular dark field scanning transmission electron microscopy has been becoming one of the most important characterization methods for materials research, due to the easy interpretation of its images in relation to the atomic structures of materials. With the aid of image simulation technique, the experimentally acquired images can even be interpreted quantitatively in terms of three-dimensional atomic structures and chemistry. However, the scanning transmission electron microscopy image simulation is generally very time-consuming in computing, which limits its application. In the present study, we established an accelerated image simulation program based on an improved multislice algorithm and graphic processing unit hardware which accelerates the calculation process. Meanwhile, by evaluating the influence of smaller probe matrix size on the convergent beam electron diffraction, it is found that this image simulation program can be accelerated further by using a smaller probe matrix size, but with high precision retained, since the error of the method occurs mostly at low angle scattering region. For high angle electron scattering, its error can be ignored. Besides, the spherical-propagation-corrected multislice method and the fully-corrected multislice method are also implemented in the program to simulate the dynamic electron-material interaction for both high-and low-energy（scanning） transmission electron microscopy. The algorithm is programmed in C＋＋ language with user-friendly interface, which can even serve as a plugin of the widely used Gatan Microscopy Suit software.

关 键 词：图像模拟 GPU加速 高角环形暗场像 低能电子衍射 

分 类 号：TP391[自动化与计算机技术—计算机应用技术] TG115.215.3[自动化与计算机技术—计算机科学与技术]