为实现大空间复杂工件的准确测量, 精确校准立体视觉系统变得越来越重要。提出了一种利用光学参考棒, 基于单位四元数法的灵活、有效的立体视觉测量系统现场校准技术。该方法以光学参考棒为校准靶标, 以参考棒上的三个共线的距离已知的红外LED作为特征点, 通过在测量范围内不同位置对光学参考棒上特征点成像, 灵活、有效地实现两摄像机之间的外参校准。参数校准过程中, 自动地控制光强, 优化曝光时间, 从而使得不同位置处光点图像的强度一致, 并且可以获得高的信噪比, 提高校准精度。实验结果表明该方法具有相当高的在线校准精度, 在实际应用中能获得很好的效果, 最大测量误差为0.15 mm, 最大标准差为0.11 mm。

To carry out the precise measurement of large-scale complex workpieces, accurate calibration of the stereo vision measurement system has been becoming more and more important. This paper proposes a flexible and reliable camera calibration of stereo vision measurement system based on unit quaternions with optical reference bar, which has three small collinear infrared LED feature points and the lengths between these feature points have been precisely calibrated. By imaging the optical reference bar at different locations and orientations over the measurement volume, we can calibrate the stereo vision measurement systems. During the calibration process, we can automatically control the light intensity and optimize the exposure time to get uniform intensity profile of the image points at different distance and obtain higher signal-to-noise ratio. The experiment alresult proves that the proposed calibration method can obtain good results in the application, the maximum measurement error is 0.15 mm and the maximum standard deviation is 0.11 mm.