AUTOMATIC MEASURING SYSTEM FOR RAILROAD WHEELS

Abstract

This paper presents a vision system to measure the wear of the railroad wheels, developed for the Portuguese railway company, CP - Comboios Portugal. The developed system is based on image processing techniques to measure automatically the railroad wheels. The wheel’s profile is acquired by the illumination of the wheel through a secant horizontal light plane. The profile’s image is processed by identifying the line of the greatest light gradient. The gradient’s profile is then converted to the wheel’s radial profile by means of a coordinate transformation model, which transforms the image plane into the wheel’s radial plane A 1:1 scale static prototype is built and the calibration and testing procedures are shown. Experimental results are presented and discussed. Future improvements on the developed prototype will allow dynamic measurements at slow speeds (5km/h), as the present developed image system was designed to eliminate distortions due to the wheel’s movement.