利用交叠成像技术的表面微观轮廓检测的研究

发布时间：2018-07-09 13:52

本文选题：交叠成像技术 + 表面微观轮廓　；参考：《南京理工大学》2017年硕士论文

【摘要】：交叠成像技术(ptychography)具有典型的无透镜成像特点,其成像系统结构简单,并且具有成像范围可扩展,成像分辨率高等优点。本文围绕交叠成像技术展开表面微观轮廓检测研究,提出了一种基于交叠成像技术的表面微观轮廓检测方法。从交叠成像技术的基本原理出发,通过数理分析论证了采集多幅交叠相干衍射图可以实现相位恢复的正确性。总结了交叠成像技术的特征与发展历程,掌握 ePIE 算法(extended ptychographic iterative engine),为利用交叠成像的表面微观轮廓检测研究奠定理论基础。基于待测物的表面微观轮廓对入射照明光的调制作用,设计一个改进的交叠成像系统,利用可变光阑与透镜的组合方式控制照明光场,便于满足不同检测需求。模拟仿真了台阶高度与噪声对纯相位台阶板复原结果的影响,结果表明对于相位台阶板检测的台阶高度不能超过1.5λ,相干衍射图的随机噪声低于5%时复原质量较高。光学实验中选取计算全息板(CGH)为样品,通过照明光场的改变实现了表面微观轮廓的检测与相位台阶特征尺寸的提取。利用精确度较高的白光干涉轮廓仪检测CGH,将基于交叠成像技术的表面微观轮廓检测结果与之比较,台阶高度的误差小于30nm,验证了本文提出的检测系统有着较高的检测精度及可靠性。针对交叠成像技术中扫描位移误差问题,本文引入一种位置误差校正模拟退火算法,仿真与实验表明该算法可以提高复原结果的分辨率,位置误差可降低到亚像素级别。
[Abstract]:Overlapping imaging technology (ptychography) has the advantages of typical lensless imaging, simple structure and high imaging resolution. This paper focuses on the research of surface micro-contour detection based on overlapping imaging technology, and proposes a surface micro-contour detection method based on overlapping imaging technology. Based on the basic principle of overlapping imaging technology, the correctness of phase recovery by collecting multiple overlapping coherent diffraction patterns is proved by mathematical analysis. In this paper, the characteristics and development of overlapping imaging technology are summarized. Grasping the EPI algorithm (extended ptychographic iterative engine), lays a theoretical foundation for the research of surface micro-contour detection using overlapping imaging. Based on the modulating effect of the microscopic profile of the surface of the object under test on the incident illumination, an improved overlapping imaging system is designed. The illumination field is controlled by the combination of the variable aperture and the lens, which is convenient to meet the different detection requirements. The effect of step height and noise on the restoration results of pure phase step plate is simulated. The results show that the step height detected by phase step plate can not exceed 1.5 位, and the recovery quality is higher when the random noise of coherent diffraction pattern is lower than 5. In the optical experiment, the CGH is selected as the sample, and the detection of the surface microscopic profile and the extraction of the phase step feature size are realized by changing the illumination light field. Using the high-precision white light interferometric profilometer to detect CGH, the surface micro-contour detection results based on overlapping imaging technology are compared. The error of step height is less than 30 nm, which verifies the high accuracy and reliability of the proposed detection system. In order to solve the problem of scanning displacement error in overlapping imaging, a position error correction simulated annealing algorithm is introduced in this paper. Simulation and experiments show that the algorithm can improve the resolution of the restoration results, and the position error can be reduced to sub-pixel level.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O439

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