基于光学自准直的航空相机自动调焦系统  

Autofocusing system based on optical autocollimating for aerial camera

作　　者：许兆林[1] 赵育良[1] 张玉叶[1] 

机构地区：[1]海军航空工程学院青岛分院,山东青岛266041

出　　处：《光学仪器》2011年第2期52-56,共5页Optical Instruments

摘　　要：分析了摄影环境的大气压力和温度的变化对航空相机离焦的影响,介绍了基于光学自准直的自动调焦系统的硬件电路原理和软件流程设计。基于光学自准直的检焦技术,选用两种图像清晰度评价函数,运用爬山搜索法采用变步长进行检焦控制,不仅有效地节省了检焦时图像处理的时间,而且提高了检焦的精度。通过引入高度和摄影角度数据,进行离焦量计算,通过控制驱动电路调整CCD的位置来完成自动调焦过程。经过光学测试和试飞证明,该系统满足了航空相机调焦精度要求。For the out of focus in aerial camera caused by the changes of atmospheric pressure and temperature during aerial photograph is analyzed. The principle of hardware theoretic electric circuit and the software design of autofocusing system based on optical autoeollimating are introduced. The autofocusing method based on optical autocollimating choosed step length changing control by employing the hill-climbing algorithm with two image definition criterion function, which not only reduces the load for data processing, but also enhances the accuracy of focusing. By receiving the data of altitude and photographic angle to calculate out of focus, the system can adjust the CCD position to realize autofocusing by controlling a driving circuit. The conclusion of the optical measurement and flight indicates that the system meets the requirements of the accuracy of focusing of aerial camera.

关 键 词：航空相机 离焦 自动调焦 自准直 图像清晰度评价函数 

分 类 号：V475.3[航空宇航科学与技术—飞行器设计] TP391[自动化与计算机技术—计算机应用技术]