Development of a digital close-range photogrammetric bridge deflection measurement system

This paper introduces a new close-range photogrammetric bridge deflection measurement system that has high accuracy and efficiency, and can be conveniently used by engineers without help from professional surveyors. After a general description of a photogrammetric bridge deflection measurement system, four critical components of the system are addressed in detail: camera selection and settings; camera calibration; network control (reference system and scale); and camera placement. The system configuration is introduced and the system is verified through the laboratory and field tests.