Towards fully automated unmanned aerial vehicle-enabled bridge inspection: Where are we at?

In recent years, Unmanned Aerial Vehicles (UAVs) have been increasingly used for bridge inspection. Although UAVs are expected to automate the whole bridge inspection process ranging from data collection and analysis to decision-making, most existing efforts still require substantial human intervention. There is currently no study that examines the state-of-the-art of automated UAV-enabled bridge inspection (UBI). This study conducts a systematic review of 115 journal articles published from 2007 to 2021 to understand the level of automation (LoA) of existing UBI approaches, highlight challenges and guide future research. The data collected was coded through a template analysis and assessed against a pre-designed LoA scale for UBI. Bibliometric and LoA analyses present in-depth insights into UBI both quantitatively and qualitatively. Furthermore, relevant challenges and future research opportunities towards fully automated UBI are discussed.