An imaging system for visual inspection and structural condition monitoring of railway tunnels

This paper details a complete hardware and software system designed to aid in the visual inspection and structural condition monitoring of railway tunnels. The system consists of two main components; an image acquisition system for data collection and an image processing software package for data analysis. The image acquisition system consists of an array of cameras with overlapping fields of view, a uniform lighting solution and a computer to control recording mounted on a rail trolley. The software package carries out operations such as image registration and stitching, 3D reconstruction and change detection. This software package is designed to generate and present image information in a manner which is most useful to structural examiners. The overall system aims to reduce the time taken to carry out visual inspection of tunnels while increasing the overall accuracy of inspections. Our preliminary findings indicate that the system directly benefits examiners when carrying out visual tunnel inspections.