基于双目视觉的轨道纵向位移测量方法

Track Longitudinal Displacement Measurement Method Based on Binocular Vision

轨道纵向位移测量是保证铁路安全运营的一项重要检测项。针对一般非接触式视觉测量技术无法区分不同轨道监测点的问题,提出一种基于双目视觉的轨道纵向位移测量方法。首先设计一种带编码的标志物,并将其固定在多个监测点的轨腰处,使用双目相机拍摄编码标志物位移前后图像。在算法实现方面,通过零均值归一化互相关法和坐标系转换模型,求出模板中心的空间坐标,以测量轨道的纵向位移。同时,提出一种一维像素扫描的方法,解析标志物所带的编码信息,以识别不同轨道监测点对应的编码值。在实验室进行合理有效的模拟试验,结果表明,本文方法在2.0 m的工作距离,测量轨道纵向位移平均误差率为1.90%,编码识别率为100%,证明了该方法的准确性和可行性,为后续开展轨道几何整体平顺性评估奠定了基础。

Longitudinal displacement measurement of track is an important inspection item to ensure the safe operation of railway. In order to solve the problem that the general non-contact vision measurement technology cannot distinguish different track monitoring points, a method for measuring the longitudinal displacement of the track was proposed based on binocular vision. Firstly, a coded marker was designed and fixed at the waist of the track at several monitoring points. Binocular camera was used to take images of the coded marker before and after displacement. In terms of algorithm realization, the spatial coordinates of the center of the template are obtained by means of zero-mean normalized cross-correlation method and coordinate system conversion model to measure the longitudinal displacement of the track. At the same time, a one-dimensional pixel scanning method is proposed to analyze the coding information carried by markers to identify the coding values corresponding to different orbital monitoring points. A reasonable and effective simulation test was carried out in the laboratory. The results show that the average error rate of the proposed method is 1.90% and the coding recognition rate is 100% at the working distance of 2.0 m, which proves the accuracy and feasibility of the proposed method and lays a foundation for the subsequent evaluation of the overall ride comfort of orbit geometry.