自由双目立体视觉摄像机动态外参数的获取

Acquisition of camera dynamic extrinsic parameters in free binocular stereo vision system

针对自由双目立体视觉中由于摄像机旋转导致的摄像机外参数变化的问题,提出一种基于旋转轴标定的动态外参数获取方法。在多个不同位置,立体标定得到多组旋转平移矩阵,利用最小二乘法求解旋转轴参数;结合初始位置左右摄像机的内、外参数及旋转角度,实时获取左右摄像机的外参数。利用所提方法获取动态外参数,并对棋盘角点进行三维重建,平均误差为0.241 mm,标准差为0.156 mm;与基于多平面标靶的标定方法相比,精度高且操作简单。所提方法无需实时标定,可完成摄像机旋转情况下动态外参数的获取。

Aiming to solve the change of the extrinsic parameters between the two cameras in free binocular stereo vision system caused by the rotation of the cameras, a method for acquiring the dynamic extrinsic parameters based on calibration of rotation axis was proposed. Multiple rotation and translation matrixes were obtained by the calibration at different positions, then the parameters of rotation axis could be calculated by using least square method. Combined with the intrinsic and extrinsic parameters at initial position and rotation angle, the dynamic extrinsic parameters between the two cameras could be calculated in real time. The chessboard corners were reconstructed with the dynamic extrinsic parameters calculated by the proposed method, the result showed that the average error was 0.241 mm and the standard deviation was 0. 156 mm. Compared with the calibration method based on multiple-plane calibration target, the proposed method is easier to implement and has higher precision, where dynamic extrinsic parameters can be acquired without real-time calibration.