Method for measuring multi-point displacements of structures using Hough transform and optical flow tracking

In structural health monitoring (SHM), recent advancements in computer vision measurement techniques have superseded the constraints imposed by conventional sensors. This paper introduces a multi-point displacement measurement method that integrates the Hough transform with the optical flow method. The technique detects circular markers, extracts the centre of the circle using the Hough transform and utilises optical flow to track the centre of the circle, enabling multi-point displacement measurement. This approach is not only applicable to translational targets but also to rotational targets. To enhance marker recognition and tracking accuracy, super-resolution generative adversarial network (SRGAN) preprocessing is introduced to improve image details. The maximum vibration error during the shaker test was 0.09 mm. The experimental results demonstrate that the proposed method achieves high accuracy and stability under different vibration frequencies, rendering it suitable for non-contact dynamic monitoring of complex structures.