Civil Engineering May 2021 | Vol 29 No 4

34 May 2021 Civil Engineering the trial installation and that the next step of developing an autonomous track defect detector is now much closer. MAPPING AND HOVERING WITH DRONES AND LiDAR Recent additions to state-of-the-art moni- toring and mapping equipment in UP’s Department of Civil Engineering include that of the Emesent Hovermap LiDAR system, infrared thermoIMAGER camera and the DJI Matrice M300 UAV, all of which have opened a realm of opportuni- ties for application in the railway sector. Hovermap is a mobile LiDAR scanning system where data capture can take the form of handheld, vehicle- or drone- mounted scans. An onboard computer encased within the Hovermap allows simultaneous localisation and mapping (SLAM) algorithms to generate point clouds of the scanned environment. The real-time processing of this data has changed the way one operates drones, with autonomous functions now available that enable programmable flights in GPS- denied environments, collision avoidance and position hold. The Hovermap, initially intended for underground mining, is easy to use and comes with 480 GB onboard storage, allowing a full day of scanning to be re- corded and downloaded at the end of the day. The final product is a high-resolution, data-rich point cloud that can be exported in non-proprietary, open-source formats (.las .laz .ply .dxf) for post-processing in third party software. Work currently underway aims to conduct a full performance evaluation of the Hovermap system in terms of its accuracy, data density, and object detec- tion capabilities. This evaluation will prompt future railway research and assist in understanding the capabilities of the Hovermap system. This will allow users to further exploit its advantages in the space of railways. Emesent’s recent release of the GoPro attachment enables colourisation of point clouds, increasing the possibilities of data capture and analysis. The thermoIMAGER infrared camera, another recently acquired item in the rail department, provides high resolution non-contact temperature measurements. The compact size of this high-resolution camera makes it an ideal attachment for drones. It can perform both static and in-motion scans of different object surfaces, with the ability to measure temperatures accurately at millisecond intervals (80 Hz). The integration of thermal and colour- isation information into 3D point clouds obtained from the Matrice M300 drone and Hovermap system (see Figure 5), will be used to conduct bridge and tunnel inspections in difficult to reach places or areas that are too dangerous for personnel to access. The study forms part of a bigger end goal which is to combine various tools, scanners, and sensors to achieve a complete condition monitoring system that will form part of or be fitted to the RRV for both road and rail infrastructure inspections and condition monitoring. SMART DIAGNOSTICS WITH CLEVER TRACK COMPONENTS Structural health monitoring in railway infrastructure is not a new concept, but the application of fibre optic sensors (FOS), for the purpose of monitoring, Figure 5 DJI Matrice M300 drone with Hovermap LiDAR system and GoPro colourisation