大视场双目立体视觉的摄像机标定

Camera calibration of binocular stereo vision with large field of view

针对大视场视觉测量应用,在分析摄像机成像模型的基础上,设计制作了可自由转动的十字靶标,实现了大视场双目视觉摄像机的精确标定。将十字靶标在测量空间内多次均匀摆放,两摄像机同步拍摄多幅靶标图像。由本质矩阵得到摄像机参数的初始值,采用自检校光束法平差得到摄像机参数的最优解。该方法不要求特征点共面,仅需要知道特征点之间的物理距离,降低了靶标制作难度。采用TN3DOMS.S进行了实测,在1500mm×1500mm的测量范围内测试标准标杆,误差均方值为0.06mm。

Aiming at the application of vision measurement in large field of view, an accurate field calibration method of binocular stereo vision camera for large field of view is proposed. A calibration cross is used to be the calibration object. This method only requires the cameras to observe the calibration cross shown at a few different orientations. Then based on the essential matrix of the two cameras, all initial values of camera parameters can be acquired. The self calibration bundle adjustment algorithm is used to optimize the calibration parameters. The coded points are not required to be planar and only the distance between two ring coded points needs measuring. So the fabrication difficulty of the calibration cross is reduced The experiment result shows that the predicted accuracy with the proposed model is 0.06 mm in the measurement range of 1500 mm× 1500 mm by using TN3DOMS.S.