光学 精密工程, 2014, 22 (3): 602, 网络出版: 2014-04-24
大视场时间延迟积分CCD遥感相机的精密定焦
Precise focusing for TDICCD camera with wide field of view
遥感相机 大视场 时间延长积分CCD(TDICCD) 精密定焦 remote sensing camera wide field of view Time Delay Integration(TDI) CCD precise focusing
摘要
介绍一种可以广泛应用的时间延迟积分(TDI)CCD拼接型焦面的精密定焦技术。首先, 在恒温、隔振条件下将满足拼接精度要求的TDICCD焦面组件粗装至相机相应的设计位置; 然后, 通过数据采集与处理系统获得相机成像的调制传递函数(MTF), 并通过调焦机构进行调焦, 测得每片TDICCD所成像的MTF调焦量曲线, 进而得到每片TDICCD的最佳像面位置; 最后, 根据8片TDICCD各自的最佳像面位置拟合出共同的相机最佳像面, 并依此确定焦面组件外接口的修调量, 完成相机焦面的精密定焦与装调。对定焦精度的分析表明, 定焦误差为9.1 μm, 与焦深的相对误差为4.4%。最终的MTF测试实验表明,8片TDICCD的MTF值比较平均, 符合相机光学镜头的MTF变化规律并且远远高于该相机全视场静态MTF≥0.2的技术指标要求。本文所介绍的大视场TDICCD遥感相机的精密定焦技术可以为同类遥感相机的研制提供借鉴。
Abstract
A precise focusing technology for a spliced TDICCD camera was introduced. Firstly, the components of focal plane were assembled to the designed locations on the camera under the circumstance of a constant temperature and vibration-isolation. Then, the Modulation Transfer Function(MTF) of the camera image was obtained through a data acquisition and processing system, the curve of MTF-focus value of every TDICCD image was plotted, and the optimum imaging plane of every TDICCD was obtained. Finally, the common optimum imaging plane of the 8 chips for TDICCD was fitted according to the every single optimum imaging plane obtained above, and then the machining values of the external interfaces of the focal plane components were derived to finish the assembly and adjustment. Precision analysis on the focusing shows that the focusing error is 9.1 μm and the relative error to the depth of field is 4.4%. The MTF test indicates that the 8 chips of TDICCD have approximately even MTF values, which are high than the camera′s static MTF requirement of 0.2. Obtained results coincide with the variation regularity of the camera′s optical MTF values and can provide references for the precise focusing technologies of the same kinds of remote sensing cameras.
孙继明, 郭疆, 邵明东, 杨近松, 朱磊, 龚大鹏, 齐洪宇. 大视场时间延迟积分CCD遥感相机的精密定焦[J]. 光学 精密工程, 2014, 22(3): 602. SUN Ji-ming, GUO Jiang, SHAO Ming-dong, YANG Jin-song, ZHU Lei, GONG Da-peng, Qi Hong-yu. Precise focusing for TDICCD camera with wide field of view[J]. Optics and Precision Engineering, 2014, 22(3): 602.