Auto inspection system using a mobile robot for detecting concrete cracks in a tunnel

To assess the safety of concrete structures, cracks are periodically measured and recorded by inspectors who observe cracks with their naked eye. However, manual inspection is slow and yields subjective results. Therefore, this study proposes a system for inspecting and measuring cracks in concrete structures to provide objective crack data to be used in evaluating safety. The system consists of a mobile robot system and a crack detection system. The mobile robot system is controlled to maintain a constant distance from walls while acquiring image data with a Charged Couple Device (CCD) camera. The crack detection system extracted crack information from the acquired image using image processing. To ensure accurate crack recognition, the geometric properties and patterns of cracks in a structure were applied to the image processing routine. The proposed system was verified with laboratory and field experiments.