Measurement of the position of the overhead electric-railway line using the stereo images

Abstract

In this paper, we propose a method that measures the height and stagger of an overhead electric-railway line using the stereo images. Two 1624 × 1236 pixel area scanner CCD cameras are used. To quickly and accurately extract, from a photographed image, the area of the overhead line on which the line laser is shone, we consider the established fact that the overhead line is the lowest among the electric wires. And to precisely measure the height and stagger in low resolution, sub-pixel and line fitting methods are used. Also, because of the different pixel resolution of the camera according to the overhead line position, we compensate the measurement result through camera calibration. We aimed for a measurement accuracy of 1mm error and indeed our experimental results show that the proposed method achieves that.