摘要
空间机械臂可见光测量相机参数标定是制约空间合作目标三维位姿测量精度的关键技术和重要前提,它直观表征了视觉标记三维坐标与对应的二维图像坐标之间正确的映射函数。针对现有相机内外参标定方法操作步骤繁琐、积累误差大、标定精度低等工程问题,文章提出一种空间机械臂可见光测量相机内外参标定方法,引入高精度二维棋盘格标定靶与基准镜共同作为转换中介,且在相机有效观测视场内随意移动标定靶,分布式解算相机内参和外参。试验表明,相机内参离散度均不超过±0.3像元,角点重投影误差均不超过±0.5像元;外参六自由度分量标准差均不超过(0.6mm,0.05°)。上述标定方法具有较强的可操作性,极大简化了坐标转换计算复杂性,有效降低了标定过程中产生的积累误差,为机械臂实施视觉闭环自主捕获合作目标提供了可靠依据。
Parameter calibration is the key technique in measuring 3D pose of cooperative object by visible photographic camera for space manipulator,which can be used to represent a correct mapping function between 3D coordinates of visual target and its corresponding 2D image coordinates.The relateded coefficient matrix of characteristic parameters involves the estimation of intrinsic and extrinsic parameters calibration of photographic camera.To solve problems existed in the traditional calibrating technique,such as complicated operating steps,large accumulating error and poor accuracy,a novel approach is proposed by introducing a measuring reference combining a precise 2D planar target with a known checkerboard pattern and a datum mirror,which can accurately calculate intrinsic and extrinsic parameters step by step.Experimental results have shown that the standard deviation of intrinsic parameters lies in±0.3pixel,with the re-projection error of corners not exceeding±0.5pixel and the standard deviation of six degrees of freedom less than(0.6mm,0.05°).Accordingly,the proposed approach has obvious advantages at good maneuverability,fewer computing steps and smaller accumulating error,which can provide reliable 3D pose to assist space manipulator to capture the cooperative object.
作者
谭启蒙
贾馨
陈磊
张运
蔡铮
TAN Qimeng;JIA Xin;CHEN Lei;ZHANG Yun;CAI Zheng(Beijing Key Laboratory of Intelligent Space Robotic System Technology and Applications,Institute of Spacecraft System Engineering,CAST,Beijing 100094,China;Beijing Institute of Space Mechanics&Electricity,Beijing 100094,China)
出处
《航天返回与遥感》
CSCD
2018年第5期113-122,共10页
Spacecraft Recovery & Remote Sensing
关键词
可见光测量相机
内外参标定
平面标定靶
基准镜
空间机械臂
photographic camera with visible light
calibration of intrinsic and extrinsic parameters
planar target
datum mirror
space manipulator
