基于相位偏折术的天文光学镜面面形检测技术

项目名称： 基于相位偏折术的天文光学镜面面形检测技术

项目编号： No.11303068

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 李博

作者单位： 中国科学院国家天文台南京天文光学技术研究所

项目金额： 27万元

中文摘要： 先进天文望远镜中广泛使用的自由曲面镜面具有非旋转对称或高非球面度的特点，难以采用传统检测手段测量面形。相位偏折术是一种通过探测标准条纹经过被测镜面反射后的变形量进行面形检测的技术，因兼具灵活性、测量效率和测量精度，可用于自由曲面的测量。然而，该技术尚存在Gamma畸变、成像畸变校正以及从梯度恢复原始相位等难点，严重限制了其测试精度和应用范围。为此，本课题以相位偏折术为研究对象，引入载频交叠重构术抑制Gamma畸变，并提出虚拟补偿法以保留更多的高频有效信息；提出以合成孔径投影法为大口径在线标定提供标靶，以建立相机畸变模型，从而校正系统成像畸变；提出以相位延拓法对区域重构法进行改进，解决由梯度恢复原始面形时孔径边缘误差较大的问题。基于以上方案，通过对不同面形镜面的测量研究，完善相位偏折术的理论和技术，以满足天文光学镜面检测对于灵活性、精度和效率的要求。

中文关键词： 镜面检测；自由曲面；载频交叠重构术；相位恢复；

英文摘要： The free-form mirrors widely used in the advanced astronomic telescope are usually rotational asymmetrical or highly aspherical, therefore their surface shapes are hard to measure by the traditional methods. The phase measuring deflection (PMD) technology is suitable for the free-form testing due to its flexibility, efficiency and accuracy, which is based on the deformation detection of the reflection image of the standard fringes by the test mirror. However, its accuracy and application is affected by the difficulties of the Gamma distortion correction, the imaging distortion correction and the shape retrieving from the slope data. To solve these problems, the PMD will be researched in the project, and the carrier squeezing interferometry is introduced to suppress the gamma distortion, while the virtual compensation method is proposed to reserve more valid information with high frequency. The stitching aperture method is proposed to generate standard markers to construct the distortion model so the imaging distortion can be corrected, which is especially useful when measuring the large mirror. Besides, the phase expanding method is proposed to improve the zonal reconstruction algorithm when retrieving the shape from the slope data so that the serious error around the aperture edge can be evaded. These theories

英文关键词： mirror testing；free-form surface；carrier squeezing interferometry；phase retrieving；