Scheimpflug Camera–Based Technique for Multipoint Displacement Monitoring of High-Speed Railway Bridges

Conventional cameras, constrained by their field of view (FOV) and depth of field (DOF), face significant challenges in achieving high-precision, synchronous multipoint displacement monitoring of large-scale bridges using a single unit. The Scheimpflug camera, which can simultaneously measure multipoint displacement, provides a promising solution for monitoring extensive bridge structures with one device. However, existing methods that employ the Scheimpflug camera for this purpose have not yet been validated in real-world bridge monitoring scenarios. Building on current approaches, this study develops a monitoring system that integrates a Scheimpflug camera, dedicated targets, train detection equipment, and a displacement calculation terminal. Deployed to monitor the dynamic displacements of simply supported beam structures under high-speed railway conditions in Xianning, Hubei Province, China, the system effectively performed multipoint vertical displacement assessments. It provided detailed insights into the spatiotemporal deformation evolution of the bridges during train transits. Results confirmed that the system can accurately measure multipoint vertical displacements across the entire bridge span. Comparison with measurements from an LVDT at the midspan revealed high consistency. The system achieved a root-mean-square error (RMSE) of less than 0.03 mm and a maximum error below 0.1 mm. This Scheimpflug camera–based system presents a groundbreaking approach for precise displacement monitoring and safety evaluations of large-scale bridges.