基于曲率/斜率混合传感的镜面视宁度检测方法

随着光学元件的口径增加，无论是在加工检测还是在站址观测过程中，镜面视宁度的影响已经越来越难以忽略。在此情况下，研究可以定量测量镜面视宁度的方法与设备就显得十分重要。基于曲率/斜率混合传感策略，结合冷冻湍流假设实现镜面视宁度评价在时-空域上的转化，实现对镜面视宁度大动态范围的检测。首先，对曲率/斜率混合传感的基本方法进行了理论推导，并以标准化点源敏感性作为评价指标进一步分析了检测过程中的镜面视宁度变化。实验结果显示，在热扰动流场较为均匀时，镜面视宁度的影响较流场反复变化时小，由于湍流不稳定所引入点源敏感性（PSSn）为0.971 8。实验结果证明基于曲率/斜率混合传感的方法可以定量分析大口径光学元件镜面视宁度，对于后续开展的大口径系统设计优化与检测加工具有很好的指导意义。

Detection method of mirror seeing based on curvature/ slope hybrid sensing

With the increase of aperture of optical elements, the influence of mirror seeing has become more and more difficult to ignore in the process of processing inspection and observation. For strong turbulence, slope detection is used to qualitatively analyze low order components. After the airflow is stable, curvature sensor can be used for fine measurement. After the slope detection, the back-end optical path of the autocollimator can be focused, and the system can be defocused to a certain amount (the defocusing direction of the two autocollimators is opposite), that is, the estimation of wavefront curvature can be obtained by the differential of wavefront along the optical axis. After obtaining the data, the results can be statistically analyzed based on point source sensitivity (PSSn) theory. Firstly, the basic method of curvature/slope hybrid sensing was deduced theoretically. The normalized PSSn was proposed by the US 30-meter telescope (TMT) to evaluate the overall performance, shape and distribution of systematic error and the change of mirror tranquility in the detection process were further analyzed with the PSSn as the evaluation index, the PSSn introduced by turbulence is 0.9718. The experimental results show that when the thermal disturbance flow field is relatively uniform, the influence of specular visibility on the flow field changes little with repeated changes. The work can quantitatively analyze the specular visibility of large-aperture optical elements, which is of great guiding significance for the optimization of large-aperture system design and detection processing.