Equation Chapter 1 Section 1 nontarget-based displacement measurement using LiDAR and camera

The nontarget-based displacement measurement approaches that use structural features have been developed for the wider adoption of computer vision-based methods in real-world applications. However, nontarget-based approaches still require the target or known structural metric information to obtain the displacement. This study proposes a nontarget-based displacement measurement method using LiDAR combined with a camera. The displacement calculation from the acquired image and point cloud information was presented based on coordinate transforms from the image to the world coordinate system. The proposed method was also designed to compensate measurement errors caused by out-of-plane motion. The proposed method was validated in two laboratory experiments and field testing using a full-scale railway bridge.