交比不变获取标定点的不确定性分析

在基于交比不变原理基础上，提出了一种估计光平面上标定特征点的世界坐标的多组取平均的方法。利用多于3组4个共线已知坐标的特征点，分别估计光平面上标定特征的世界坐标，然后取平均值作为标定特征点的世界坐标，可以有效地获取高精度的结构光标定特征点。分析了影响特征点估计精度的不确定性因素，并给出了估计不确定度的评定方案。通过仿真实验验证了所提出的基于交比不变标定特征点估计不确定度评定方案的有效性，并对多种特征点什计方法进行了试验与比较，提出了进一步提高估计精度的措施，为交比不变在计算机视觉领域的应用奠定了基础。

Uncertainty Analysis of Constructing Calibration Points Based on Invariance of Cross Ratio

Based on the invariance of cross ratio, an effective method that employs more than three groups with four collinear feature points to compute accurate coordinates of the feature points falling on the light stripe plane is discussed,and the factors that may effect on the coordinates estimation accuracy are analyzed in detail. A solution to evaluate the uncertainty of constructing the feature points with invariant cross ratio is proposed. The simulation experiments reveal that the proposed approach is valid and feasible for the structured light vision sensor calibration. Furthermore, compared different methods to construct feature points with coordinate estimation uncertainty,the effective method to generate high accurate feature points is proposed, it is shown that the invariance of cross ratio can be applied more broadly in the filed of computer vision.