机载设备安装姿态视觉校准中的靶板标定

Target plate calibration for vision-based airborne equipment mounted attitude boresight

基于飞机机载设备安装姿态视觉校准系统Archer-M的研发,提出针对系统中姿态测量辅助靶板的标定方法.首先,利用摄像机从不同方位拍摄靶板图像,在相差一个尺度因子的情况下确定靶点位置关系.然后,利用单个发光二极管（LED）靶点的多次精确移动和图像叠加的方法恢复绝对尺度,求解靶点的相对关系.最后,通过精确控制靶板的位姿运动,利用运动前后各坐标系之间的相对关系,求解出“靶/座”相对位姿,并进一步针对只用于物体姿态测量的靶板,提出了分别沿两个垂直方向运动的简化“靶/座”标定方法,从而大大降低了标定过程中对标定设备的要求.实验结果表明：距离为3～12 m时,姿态角度的测量标准差为0.004～0.017°,姿态测量精度与激光跟踪仪相当.

On the basis of the development of a novel vision-based airborne equipment mounted an attitude boresight system, a calibration method of the target plate for measurement of the object position and attitude was proposed. Firstly, the coordinates of target points on the target plate were acquired from multiple directions by using a camera, and target point locations were determined in a condition of one scale factor difference. Then, the absolute scale factor was recovered by using the multiple accurate movement of a single IR-LED and an image overlay method, and target point locations were obtained. Finally, the ＂target/base＂ relative position and attitude were solved by precisely controlling the target plate movement and by using each coordinate relationship before and after the movements. Furthermore, aimed at the target plate for the object attitude measurement, a simplified ＂target/base＂ calibration method based on movement along two vertical directions was proposed separately to reduce the equipment requirements in the calibration. Experimental results indicate that at the distance of 3--12 m, the standard deviations of attitude angle measurement are 0. 004--0. 017~, and the attitude measurement accuracy is the same as that from the laser tracker_