Cost-effective long-range measurement of structural displacement using a two-stage method integrating...

Displacement is an imperative metric for assessing structural performance. However, the accuracy of structural displacement measurement is constrained by the physical resolution of the camera, particularly in long-range monitoring scenarios. To address these constraints, a cost-effective long-range structural displacement measurement system based on a two-stage method integrating super-resolution reconstruction and sub-pixel registration (SRSR) is proposed in this study. Initially, the proposed method achieves texture detail enhancement of low-resolution images through super-resolution reconstruction, thus improving the accuracy of visual tracking. Subsequently, a continuous convolution operator based on natural texture on the structural surface is utilized to achieve accurate sub-pixel registration. Finally, the performance of the proposed methodology is verified with field tests on a scaled truss bridge and a cable-stayed bridge. The displacement measurement accuracy is significantly enhanced through the implementation of a two-stage technique based on SRSR (including steps I and II), in comparison to the utilization of the sub-pixel registration (step II only) in isolation. The cost-effective vision-based system developed in this study provides an alternative for long-range structural displacement measurement.