Infrastructure inspection aims to automate or remotely perform inspection on infrastructure that would have otherwise been manually done in a safer and more cost-efficient manner. These inspections can be part of routine inspections or repairs. Using drones equiped with cameras, inspections can be done more cheaply and more safely than having trained repair teams go to the site to conduct manual inspections, while coordinating with shut down schedules. Machine vision, LIDAR, and other image gathering and image recognition technologies are used to generate models of the infrastructure. Auto-navigation and guiding systems are used guide the unmanned vehicles, especially under bridges or in tunnels where GPS coverage can be limited. Usually infrastructure inspection is combined with condition monitoring systems that send alerts when a specific fault is detected.
Drones make inspections easier and cheaper without disturbing daily traffic. Traditionally, bridge inspections were done with the help of “snooper trucks” – vehicles with a ﬂexible crane to move an inspection engineer alongside and underneath the bridges. The vehicles are expensive to buy and costly to maintain. They also cause massive road obstructions so signs need to be erected and staff allocated to direct trafc – in many cases the bridge must be closed down completely for inspections that can take hours. Consequently, the work was often conducted at night, which made it even harder to detect problems. Using inspection drones allows inspection during daytime hours without causing any disruption. Instead of needing a team of seven to 10 specialists, a bridge can now be inspected by two staﬀ, and in much less time.