College of Automation, Nanjing University of Aeronautics and Astronautics, Jiangjun Road, Nanjing 211106, China.
School of Computer Science and Communication Engineering, Jiangsu University, Xuefu Road, Zhenjiang 212013, China.
Sensors (Basel). 2023 Jun 26;23(13):5929. doi: 10.3390/s23135929.
The line structured light plane calibration method using a plane target cannot produce satisfactory calibration results due to inaccurate positioning of the calibrated points. Field of view noise and sensor noise affect the target light stripe extraction and camera parameter calculation during the calibration process. These factors will cause the calculation of the coordinates of the calibrated point to deviate, and thus affect the light plane calibration. To solve this problem, we propose a new method to calculate the calibrated point based on spatial geometry. Firstly, for the projection line corresponding to the feature point on the light stripe and the corresponding line on the target, a common perpendicular of these two lines above is established, and since the sum of the squares of the distances from the midpoint to the two straight lines is the smallest, the midpoint of the common perpendicular is taken as the calibrated point. Secondly, the target is moved to different positions, and the non-collinear calibrated points are calculated. Finally, the parameters of the light plane are obtained by fitting these calibrated points. This method requires only a checkerboard target, and has a simple calibration process. The experimental results show that the average error of the calibration method proposed in this paper is 0.011 mm, which is less than the 0.031 mm of the calibration method based on the plane target with cross-ratio invariant.
基于平面靶标的线结构光平面标定方法，由于标定点定位不准确，无法得到满意的标定结果。视场噪声和传感器噪声会影响标定过程中的目标光条纹提取和相机参数计算，这些因素会导致标定点坐标的计算产生偏差，从而影响光平面标定。为了解决这个问题，我们提出了一种基于空间几何的新的标定点计算方法。首先，对于光条纹上特征点对应的投影线和目标上对应的线，建立这两条线的公共垂线，由于从中点到两条直线的距离的平方和最小，所以取公共垂线的中点作为标定点。其次，移动目标到不同的位置，计算非共线的标定点。最后，通过拟合这些标定点得到光平面的参数。该方法仅需要一个棋盘格目标，标定过程简单。实验结果表明，本文提出的标定方法的平均误差为 0.011mm，小于基于交比不变的平面靶标标定方法的 0.031mm。
