摘要
为了补偿航空相机在高空中由于气压、温度等环境变化引起的离焦,本文设计了一个基于光电自准直方法的航空相机自动检调焦系统。利用相机内部高对比度光栅进行调焦,有效避免了基于图像处理的调焦系统在目标物对比度较低时调焦失败的情况。采用物方光栅、像方光栅和反射镜摆扫的方式对光强信号进行调制,利于信号的分析处理;采用粗/精结合的遍历搜索策略进行检调焦,保证了结果的准确性。实验结果证明:整个调焦过程在20s之内完成,具有较好的快速性;重复定位精度小于1/2焦深,满足航空相机成像要求。
For compensating the defocus caused by the changes of temperature, pressure and other environmental parameters of an aerial camera in the air, an autofocusing system for aerial camera based on opto-eletronic auto-collimation method was designed. Utilizing raster with high contrast in the camera, this system avoided the situation that autofocusing based on image processing technology failed when object is with low contrast. Modulated by raster in object space, image space and the swing of reflector, the signal of light intensity was easy to be processed. Combined coarseness with fine searching strategy, the system guaranteed the validity of adjustment result. Experimental results show that the autofocusing process is accomplished in less than 20 s, and the repeatability is less than half focus depth, which satisfies the focusing requirement of aerial camera.
出处
《光电工程》
CAS
CSCD
北大核心
2011年第3期35-39,共5页
Opto-Electronic Engineering
基金
中国科学院前沿课题基金资助项目(ck0308)
关键词
航空相机
光电自准直
检调焦
aerial camera
opto-electronic auto-collimation
focus-detecting and refocusing
