大视场线结构光视觉传感器的现场标定

针对大视场线结构光视觉传感器的现场标定,提出了一种基于自由组合一维靶标的标定方法。自由组合多个一维靶标并固定,其中每个一维靶标至少包含3个共线特征点。靶标在传感器测量空间内自由摆放至少两次。以一维靶标两两之间夹角恒定为约束求解摄像机内部参数;由一维靶标消影点性质和特征点之间距离约束,求解各特征点在摄像机坐标系下的空间坐标;根据交比不变计算光平面与各一维靶标交点的摄像机坐标,拟合出光平面方程。实验表明,该方法可获得与平面靶标相当的标定精度,具有靶标加工容易、精度高、摆放次数少的特点,适合大视场线结构光视觉传感器的现场标定。

A Field Calibration Method for Line Structured Light Vision Sensor with Large FOV

A calibration method for line structured light vision sensor with large Field of View (FOV) by using 1D target with unconstrained combination is proposed. Several 1D targets, each of which has at least 3 feature-points aligned on a feature-line, are combined freely according to the measuring range of the sensor. All primitive parameters of the line structured light vision sensor are determined with observation of the target shown at a few (at least two) different viewpoints. The intrinsic parameters are solved using the invariability of angle between every two one-dimensional targets in different views. The coordinates of feature-points in the camera coordinate frame are computed in accordance with the property of the vanishing point and the known distance between the feature points. The coordinates of the control points which are the intersection points of the light plane and the feature lines are obtained based on the cross-ratio invariability. The light plane is fitted with at least three nonlinear control points. The experimental results show that the proposed approach can achieve the same calibration accuracy as the planar-target-calibration approach. Compared with existing methods, the proposed method is fast with high accuracy, which is suitable for the field calibration of line structured light vision sensor with large FOV.