High Iron Contact Line Parameter Detection Technique Based On Binocular Vision

Contact wire is an important part of the catenary of high-speed railway. The geometric parameters, such as the height, the stretch value and the wear status of the contact wire, are very important for train running safety. Therefore, it is necessary to measure the wire’s geometric parameters regularly, so as to find the security risks timely and ensure train running safety.This thesis makes a relatively comprehensive and in-depth analysis on the catenary structure, the contact wire’s geometry parameters, and the research status of the catenary detection technology and equipment, and a portable device to measure the wire’s geometric parameters based on binocular vision principle has been developed and tested under laboratory conditions.First of all, aimed at the problem that the complexity of binocular vision image processing varies greatly under different conditions, the measurement has be divided into two modes:one is texture-based automatic measurement mode, the other one is manual intervention image processing mode, which ensures the feasibility and accuracy requirements of the measuring system.Secondly, based on comprehensive analysis on binocular system’s structure parameters, two cameras’optical parameters, and the positional parameters of the measured object, the mathematical models of "texture-based automatic measurement mode" and "manual intervention image processing mode" have been established according to geometrical optics imaging principle, and the formulas to calculate geometric parameters are presented.Thirdly, according to the analysis on the characteristics of "texture-based automatic measurement mode" and "manual intervention image processing mode", the thesis presents a self-designed image processing method. Especially, the technical problem to match a characteristic point’s two images in the left camera and right camera rapidly has been solved.Fourthly, the3D design software SolidWorks has been used to accomplish the mechanical design of the portable system, which integrates gauge measurements function. The measuring system’s software is developed on the basis of the visual library OpenCV and MFC base class library under the VC++circumstances.Finally, a self-designed experimental device has been built up, and the experiments are carried out on the device according to "texture-based automatic measurement mode" and "manual intervention image processing mode" respectively, and the results have proven the feasibility and effectiveness of the measuring methods and system design.