A monocular vision-based system and method for high-accuracy structural displacement monitoring

Abstract

Structural displacement monitoring is essential for evaluating the safety and performance of civil infrastructure. This paper presents a monocular-vision-based displacement monitoring system consisting of an industrial camera, a telephoto lens, and a specially designed artificial target. A displacement calculation method combining edge detection, centroid extraction, and rotational transformation is proposed to achieve accurate two-dimensional displacement measurement. The system was validated through controlled experiments at a distance of 100 m with stepwise movements. Results show that the system can effectively track displacement changes with a root mean square error of 0.4 mm, although high-frequency noise and dynamic overshoot were observed. The proposed method offers a low-cost, non-contact solution for structural health monitoring and provides a foundation for further improvements in measurement accuracy and stability.