Hu Yao, Wang Shaopu, Cheng Xuemin, Xu Chengqiang, Hao Qun
Beijing Key Lab. for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China.
Beijing Institute of Spacecraft Environment Engineering, Beijing 100094, China.
Sensors (Basel). 2020 Feb 26;20(5):1278. doi: 10.3390/s20051278.
The deformation measurement of a specular surface is of great importance during the quality inspection and installation of optical elements or wafers, especially those with large apertures. We propose a deflectometry method with speckle digital image correlation (DeSDIC) to realize the dynamic and high-accuracy measurement of the deformation on specular surfaces, with a simple system structure and robustness to noises and environmental vibrations. Random speckle pattern displayed on liquid crystal display is reflected by the original surface under test (SUT), and the distorted pattern is recorded by a camera. This originally distorted pattern is taken as the reference image, and the patterns captured afterwards are digitally correlated with the reference image to calculate the gradient change and deformation of the SUT. The theoretical relationships and an experimental one-step calibration scheme are proposed. Both static and dynamic deformations of a deformable mirror were experimentally measured to demonstrate the feasibility and accuracy of DeSDIC, which is comparable to phase-measuring deflectometry and interferometry.
在光学元件或晶圆的质量检测和安装过程中，尤其是对于大口径的元件或晶圆，镜面表面的变形测量至关重要。我们提出了一种基于散斑数字图像相关的偏折测量方法（DeSDIC），以实现对镜面表面变形的动态高精度测量，该方法具有简单的系统结构，并且对噪声和环境振动具有鲁棒性。液晶显示器上显示的随机散斑图案由原始被测表面（SUT）反射，变形后的图案由相机记录。这个最初变形的图案被用作参考图像，随后捕获的图案与参考图像进行数字相关，以计算SUT的梯度变化和变形。提出了理论关系和实验一步校准方案。通过实验测量了变形镜的静态和动态变形，以证明DeSDIC的可行性和准确性，其与相位测量偏折术和干涉测量法相当。
