双目视觉法测量接触线几何参数的误差与灵敏度分析

Error and Sensitivity Analysis to Measure the Geometrical Parameter of Contact Wire By Binocular Vision

给出了双目视觉法测量接触线几何参数的数学模型,系统地分析了双目测量系统的结构参数和相机光学参数与测量误差及灵敏度之间的关系,并应用Matlab进行仿真计算。结果表明,双目视觉系统对接触线高度变化的灵敏度远低于对拉出值变化的灵敏度,故导高测量误差远大于拉出值测量误差。要同时提高二者的测量精度,一是通过图像处理实现亚像素分辨;二是适当增加两相机CCD光敏面中心距离2L以增大相机光轴相对垂直平面的倾斜角α,并增大相机焦距f以提高测量灵敏度,减小测量误差。

Mathematical model of binocular vision method for measuring the contact line geometry is established.The binocular measurement system structure parameters and camera optical parameters and the measurement error and the relationship between the sensitivity were systematically analyzed,and simulated by use of MATLAB.The results show that the binocular visual system sensitivity to changes in contact wire height is much lower than the sensitivity of the stagger values change,so the measuring error of contact wire＇s height is far more than the error of stagger value.In order to raise the measuring accuracy for both height and stagger value,one method is to achieve sub-pixel resolution;the second is appropriate to increase 2L,the distance between the two cameras CCD photosensitive surface center,to increase the angle of camera optical axis relative to the vertical plane,and to increase the camera focal length to improve measurement sensitivity,reduce the measurement error.