异相差分滤波效应的航空相机图像检焦方法  

Aerial camera image focusing method based on out-of-phase differential filtering effect

作　　者：康琦 郑丽娜[1] 王海江 Kang Qi;Zheng Lina;Wang Haijiang(Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [2]中国科学院大学,北京100049

出　　处：《红外与激光工程》2021年第8期229-237,共9页Infrared and Laser Engineering

摘　　要：针对航空相机焦面检测的问题,提出了一种基于异相差分滤波器的航空相机焦面检测方法。首先对空间滤波效应自动检焦原理进行介绍;其次使用异相差分检波算法设计异相差分滤波器消除空间滤波信号中的基频成分,增大信号信噪比与振幅,提高检焦精度,并对异相差分滤波器输出信号的频谱进行分析;最后设计成像实验,在5~53.2 mm/s之间根据典型速高比设置导轨移速,进行25次像面检测并选用传统图像检焦算子与差分滤波法的检焦效果进行比较。结果表明:差分滤波检焦法的场景适应性强、灵敏度高,且检焦系统最大误差为45.18μm,小于光学系统的允许误差76.8μm,满足工程需求。Aiming at the problem of aerial camera focal plane detection, an aerial camera focal plane detection method based on out-of-phase difference filter was proposed. Firstly, the principle of automatic focus detection by spatial filtering effect was introduced. Secondly, the out-of-phase differential detection algorithm was used to design out-of-phase differential filters in order to eliminate the fundamental frequency components in the spatially filtered signal, increased the signal-to-noise ratio and amplitude, and improved the focus accuracy. The frequency spectrum of the out-of-phase differential filter’s output signal was analyzed. Finally, guide rail speed between5-53.2 mm/s according to the typical speed-to-height ratio was set to perform 25 image plane inspections, and the focusing effects of traditional image focusing operators was compared with differential filtering methods. The results show that the differential filter focusing method has strong scene adaptability and high sensitivity, and the maximum error of the focusing system is 45.18 μm, which is less than the allowable error of the optical system of76.8 μm and meets the engineering requirements.

关 键 词：航空相机 图像检焦 差分滤波器 空间滤波效应 

分 类 号：V248.1[航空宇航科学与技术—飞行器设计]