基于椭圆检测的离轴抛物镜定心装调方法

Assemble method for off-axis parabolic mirror based on ellipse detecting

针对一种高精度线偏振辐射计的离轴抛物镜定心装调问题,提出了基于椭圆检测的定心装调方法。逆光路使视场光阑在相机焦面成像为光斑,采集视频图像,使用基于最小二乘拟合法的椭圆检测方法得到光斑中心运动轨迹,从而得到离轴抛物镜的光轴倾斜误差。编写装调专用辅助软件用于相机控制和图像的处理、显示,实现定心装调的定量化可视化。技师通过观察软件界面中的光斑中心轨迹的变化,判断装调的方向和力度。经验证,该方法使定心装调误差检测精度不再受限于人眼观察,有效地指导了技师装调,最终装调误差由1.33°降到0.3°,满足装调需求。

An assembling method for off-axis parabolic mirror of a high-precision polarimeter based on ellipse detecting was put forward.Using the reversing light path,the light field diaphragm could be imaged to be a focusing spot on camera.The ellipse detecting means based on least square method was adopted to trace the focusing spot and get the moving track of the center of the spot,so as to measure the shift-error of the optic axis.A special assistant-software was developed to control camera and process image.The spot's moving track was shown on the software interface,thus technicians can judge how to adjust mirror's position according to how the track is changing.It is verified that this method can guide technician assembling effectively and the shift-error of the optic axis can be detected out accurately.Finally,the assembling error is corrected from 1.33°to 0.3°which meets requirement.