【作者】 尚洋；

【导师】 于起峰；

【作者基本信息】 国防科学技术大学 ， 航空宇航科学与技术， 2006， 博士

【摘要】 本文以空间舱对接和空间机器人基于视觉对空间目标进行观测为背景,研究了测量目标位置和姿态的有关方法,并进行了地面模拟实验。由于空间的温差巨大等恶劣环境,而且存在着许多不可预知因素,使得测量系统的参数易受扰动并严重影响测量结果。为消除扰动影响,本文重点研究了抗扰动地测量目标位置姿态的方法和算法。本文开展了以下的研究工作。1).分析了像机模型参数冗余的现象,归纳出7种保持精度的简化像机模型,使摄像测量的许多方法和算法能够在保持精度的条件下得到简化,并降低了对求解条件的要求。2).对像机标定方法和算法进行了研究并提出多种标定方法。基于保持精度的简化像机模型,提出了一种基于共面控制点两步迭代标定像机的方法和一种基于共面控制直线标定像机线性参数的方法。共面特征较之异面特征更易于构造,因而这两种标定方法便于工程实施。对于像机相对于基准系外参数的标定,提出了一种借助辅助像机的全视场法和一种适用于合作目标对接问题的模拟对接测定法。还提出了一种直接求解线性方程的两步法手眼定标算法,作为对两步法手眼定标的改进,求解更加直观和简易。3).对扫描图像畸变进行了分析,提出了一种用分布于扫描图像四周的标准正交网格对全场进行标定和修正的方法,使普通扫描仪可用于精密测量。4).研究了测量目标位置姿态的方法和算法,尤其是抗扰动的测量方法。提出了一种在目标偏航角和俯仰角较小的条件下,从3个特征点单目线性粗估合作目标位置姿态的补点法,可为平差优化提供初值。提出了下述两种抗扰动地测量目标位置姿态的方法。固连修正像机的方法,通过与测量像机固连的修正像机实时监测测量像机外参数所受扰动情况,进而对其进行修正。基于光束法平差的方法,将易受扰动的测量系统参数作为平差参数与目标位置姿态参数共同进行优化求解。在单目或双目测量合作或非合作目标位置姿态时,不需对硬件进行改造,而完全从算法上实现了对像机内参数、像差系数、双像机间相对位置姿态参数以及目标结构参数所受扰动的修正。通过上述的抗扰动测量方法,能够有效解决测量系统参数扰动影响测量精度的难题,在测量系统参数受扰动的情况下,仍能得到与未受扰动时精度相当的测量结果。5).开发了空间舱对接和空间机器人视觉观测的地面模拟实验系统,设计了观测方案,并进行了数字仿真和实物仿真实验。本文所研究的方法和算法也可以在其它对摄像测量有需求的场合进行应用。更多还原

【Abstract】 In this dissertation, the methods and algorithms of vision based targets’ pose measurements are studied and ground simulation experiments are conducted. The background of the works is to measure space targets’ relative distance and attitudes for the two projects of space cabin docking and space robot application.Because of the harsh environment and lots of unknown factors in the space, videogrammetric system parameters tend to be disturbed. The disturbance will badly impact the results. To remove the infections of the disturbance, disturbance-rejecting methods of pose measurements are studied especially.The main contents of the works in this dissertation are as follows.1). Camera parameters’ redundancy is analyzed. 7 kinds of precision-reserved simplified imaging models are concluded. By using these simplified models, lots of methods and algorithms in videogrammetry can be simplified without loss of precision. With these models, the requirement on control conditions can be reduced.2). Methods and algorithms of camera calibration are studied. Several new methods of calibration are proposed.Based on the precision-reserved simplified imaging models, a method of camera calibration by two iterated steps from coplanar control points and a method to calibrate a camera’s linear parameters from coplanar control lines are proposed. Coplanar signatures are easier to be prepared than non-coplanar signatures. Thus the proposed two calibration methods are more convenient to be applied.For the calibration of cameras’ exterior parameters relative to the basic coordinate system, a panorama method by using an assistant camera and a simulated docking method which is adapted to the docking application are preposed. For the two-step method of eye-hand calibration, an algorithm by resolving linear equations is proposed. This algorithm is intuitionistic and simple.3). The aberration of scan images by a common scanner is analyzed. Then a method to calibrate a scan image by distributing standard orthogonal griddings around the scan image is presented. This method makes normal scanners be used for accuracy measurement.4). Methods and algorithms, especially the disturbance-rejecting methods of targets’ pose measurements are studied.A point filling method to estimate a cooperative target’s pose linearly and roughly from 3 points is prposed. When the target’s yaw angle and pitching angle are small, this method can provide initial values for adjustment.The following two kinds of disturbance-rejecting methods of pose measurements are proposed.One method is to fix the measuring camera with an assistant camera that observes the disturbace of the measuring camera’s exterior parameters and corrects them in real time.The other method is to take the disturbed parameters as adjusted values and modify them by bundle adjustment. By using this method to measure cooperative or uncooperative targets’ pose by monocular or binocular videogrammetric system, the disturbance on the cameras’ interior parameters, aberration coefficients and relative pose parameters between the two cameras can be removed. These disturbance-rejecting functions are realized by arithmetic-software and do not require any change on the hardware system.By the above disturbance-rejecting methods, the problems fetched from the disturbance on the videogrammetric system parameters are solved. Thus accurate measurements can be reached even if the system parameters are disturbed.5). Ground experimental systems of vision-based pose measurements for space cabin docking and space robot systems are developed. Observe systems’ schemes are designed and the data and physical simulation experiments are conducted.The methods and algorithms studied in this dissertation can also be applied on other videogrammetry tasks.更多还原