Yan Feng, Tao Xiaoping
Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, China.
Appl Opt. 2012 Apr 10;51(11):1749-56. doi: 10.1364/AO.51.001749.
Wavefront coding (WFC) is a kind of computational imaging technique that controls defocus and defocus related aberrations of optical systems by introducing a specially designed phase distribution to the pupil function. This technology has been applied in many imaging systems to improve performance and/or reduce cost. The application of WFC technology in an off-axis three mirror anastigmatic (TMA) system has been proposed, and the design and optimization of optics, the restoration of degraded images, and the manufacturing of wavefront coded elements have been researched in our previous work. In this paper, we describe the alignment, the imaging experiment, and the image restoration of the off-axis TMA system with WFC technology. The ideal wavefront map is set to be the system error of the interferometer to simplify the assembly, and the coefficients of certain Zernike polynomials are monitored to verify the result in the alignment process. A pinhole of 20 μm diameter and the third plate of WT1005-62 resolution patterns are selected as the targets in the imaging experiment. The comparison of the tail lengths of point spread functions is represented to show the invariance of the image quality in the extended depth of focus. The structure similarity is applied to estimate the relationship among the captured images with varying defocus. We conclude that the experiment results agree with the earlier theoretical analysis.
波前编码（WFC）是一种计算成像技术，它通过向光瞳函数引入特殊设计的相位分布来控制光学系统的离焦和与离焦相关的像差。该技术已应用于许多成像系统，以提高性能和/或降低成本。此前已有文献提出将WFC技术应用于离轴三镜消像散（TMA）系统，并且我们之前的工作已经对光学系统的设计与优化、退化图像的恢复以及波前编码元件的制造进行了研究。在本文中，我们描述了采用WFC技术的离轴TMA系统的装调、成像实验以及图像恢复。将理想波前图设为干涉仪的系统误差以简化装调过程，并在装调过程中监测某些泽尼克多项式的系数以验证结果。在成像实验中，选择直径为20μm的针孔和WT1005 - 62分辨率图案的第三块板作为目标。通过比较点扩散函数的尾部长度来展示在扩展焦深范围内图像质量的不变性。应用结构相似性来估计不同离焦情况下所采集图像之间的关系。我们得出实验结果与早期理论分析一致的结论。
