When measuring large, elongated structures such as tunnels, the integration of the local three-dimensional (3D) shapes measured at multiple points using tools such as laser scanners is necessary. However, because tunnel interiors often have smooth, texture-less surfaces, estimating the relative pose between measurement points is difficult. This paper proposes a lightweight 3D measurement method using a single camera and laser projection. The system performs cross-sectional shape measurements using the light-section method and pose estimation using the projected laser features. By introducing a scale optimization approach that minimizes the nearest-neighbor distances between point clouds, accurate global 3D reconstruction is achieved without relying on external sensors. The proposed method enables efficient and precise measurements, even in featureless environments.
Higuchi et al. (2026) studied this question.