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

Abstract

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.

Vision-Based Tunnel Lining Health Monitoring via Bi-Temporal Image Comparison and Decision-Level Fusion of Change Maps

“…However, literature on the detection of changes on tunnel linings is still lacking, possibly due to the challenges encountered in this area. Some of these can be referred to in [10][11][12][13][14]. A system aimed at supporting structural inspectors to monitor the condition of railway tunnels is presented in [10].…”

“…Some of these can be referred to in [10][11][12][13][14]. A system aimed at supporting structural inspectors to monitor the condition of railway tunnels is presented in [10]. An array of cameras with uniform lighting is used to capture the image data that are registered and stitched to allow tunnel inspectors to examine for defects with reference to their location.…”

Deformation Detection Method of Mine Tunnel Based on Mobile Detection System

“…Du et al [ 28 , 29 , 30 , 31 ] analyzed the cross-section deformation of a shield tunnel from the aspects of tunnel section extraction, convergence diameter calculation, and generated a gray image of a tunnel point cloud using a mobile laser scanning system that integrated scanner and odometer. Researchers have obtained tunnel information via laser point clouds and have attained certain achievements in the development of digital imaging technology [ 32 , 33 , 34 ]. However, owing to the complexity of digital image acquisition, the accuracy of tunnel structure data cannot be guaranteed and the lack of light in tunnels will also have a certain impact on data acquisition.…”

Concrete Preliminary Damage Inspection by Classification of Terrestrial Laser Scanner Point Clouds through Systematic Threshold Definition

“…Consequently, damage occurring to any part of the structure can be detected and localized. For instance, Jenkins et al [16] performed visual inspection and structural condition monitoring of railway tunnels based on imagery data and an image processing software package carrying out operations such as image registration and stitching, 3D reconstruction and change detection. Image-based health monitoring techniques to acquire 3D point clouds (PCs) on real scenes are low-cost and very precise, but the quality of the images is significantly affected by the surrounding environmental conditions and exhaustive images are needed to achieve the required resolution [17].…”