Stašík Marek, Psota Pavel, Lédl Vít, Kredba Jan
Appl Opt. 2021 Sep 20;60(27):8556-8568. doi: 10.1364/AO.433312.
Measurement of large or aspheric optical surface shapes as a single aperture using interferometry is problematic for many reasons. A typical problem is the numerical aperture limitation of the interferometer transmission element and the surface slope deviation of aspheres. This deviation typically causes vignetting and spatial aliasing on the camera. A solution is subaperture measurement and subsequent subaperture stitching. A stitching algorithm, in principle, uses overlaps between subapertures to eliminate aberrations of each subaperture to obtain a full aperture for further analysis. This process is computation time demanding and requires optimization in order to obtain a result in a reasonable time to reduce, in turn, the overall manufacturing time. In this paper, a novel, to the best of our knowledge, and fast stitching method based on a system of linear equations is proposed and mathematically described. The developed method was compared with other algorithms, and theoretical computation complexity was calculated and compared. The method was tested practically, with real data measured on spherical surfaces using QED ASI (QED Technologies aspheric stitching interferometer) and an experimental interferometer, and the results are presented. Stitching quality was quantified for results and compared to other algorithms.
使用干涉测量法将大型或非球面光学表面形状作为单个孔径进行测量存在诸多问题。一个典型问题是干涉仪传输元件的数值孔径限制以及非球面的表面斜率偏差。这种偏差通常会导致相机上出现渐晕和空间混叠。一种解决方案是子孔径测量及随后的子孔径拼接。拼接算法原则上利用子孔径之间的重叠来消除每个子孔径的像差，以获得完整孔径用于进一步分析。此过程对计算时间要求很高，并且需要进行优化，以便在合理时间内获得结果，进而减少整体制造时间。本文提出并从数学角度描述了一种据我们所知新颖且快速的基于线性方程组系统的拼接方法。将所开发的方法与其他算法进行了比较，并计算和比较了理论计算复杂度。使用QED ASI（QED技术非球面拼接干涉仪）和一台实验干涉仪对球面进行实际测量得到真实数据，对该方法进行了实际测试，并展示了结果。对结果的拼接质量进行了量化，并与其他算法进行了比较。
