基于代数重建算法的高能电子三维成像研究

本工作将代数重建算法应用于新兴发展的高能电子成像技术开展三维成像研究，实现对样品靶物质内部结构信息的精确诊断。通过蒙特卡罗程序及粒子追踪程序模拟高能电子成像过程，包括电子束与靶物质相互作用过程，获得样品靶物质成像角度下的高能电子二维成像结果。利用代数迭代重建ART(Algebraic Reconstruction Technique)算法和滤波反投影算法分别进行了高能电子三维成像仿真测试，重建出靶物质的三维图像，并将两种算法重建的断层图像用图像评价指标进行了定量对比分析。结果表明:在投影角度数为180个的条件下，ART的重建结果更接近靶物质原图，能有效抑制伪影，图像保真度较高。为进一步验证模拟结果，展开了实际实验，得到的结论与模拟结果相同。本研究结果为后续高能电子三维成像重建算法的优化提供了依据。

Study on Three-dimensional High Energy Electron Radiography Based on Algebraic Reconstruction Algorithm

In this paper, the algebraic reconstruction algorithm is applied to the newly developed High Energy Electron Radiography(HEER) technology to carry out three-dimensional imaging research, which realizes the accurate diagnosis of the internal structure information of the sample material. The Monte Carlo program and the particle tracking program are used to simulate the high-energy electron imaging process, including the interaction process between the electron beam and the target substance, and obtain the high-energy electron two-dimensional imaging results under the imaging angle of the sample. The ART(Algebraic Reconstruction Technique) algorithm and the Filtered Back Projection (Filtered Back Projection) algorithm were used to simulate experiment of Three-Dimensional High Energy Electron Radiography(TDHEER) respectively, and the three-dimensional images of the sample were reconstructed. These images have been quantitatively compared and analyzed through evaluation indexes. The results show that under the condition that the angle number of projection is 180, the reconstruction results of ART are closer to the original image of the sample, which have higher fidelity and fewer image artifacts. In order to further verify the simulation results, actual experiments were carried out, and the conclusions are the same as the simulation. The results of this study provide a basis for the optimization of the subsequent TDHEER.