Rigid-body Deformation Monitoring of Buildings Based on Terrestrial Laser Scanning (TLS) Technology

Terrestrial laser scanning (TLS) as potential approach for rigid-body deformation monitoring has various attractive characteristics', such as the direct measurement of three-dimensional (3-D) coordinates, the high degree of automation, the massive sampling capability and non-prism measurement, etc. This paper develops a new method for rigid-body deformation monitoring based on repeated TLS scans. The main ideal of the approach is the establishment of feature coordinate system based on principal component analysis (PCA) algorithm and the rigid-body deformation calculation of buildings according to transformation of feature coordinate system. Using the point cloud data of TLS, the proposed approach can not only quickly extract spatial attitudes of all monitoring body, but also provide fully 3-D deformation analysis. From the analysis of the correctness and effectiveness of proposed approach according to engineering project, the errors are no more 2 mm in the displacements and about 0.001 degrees in the rotations. The feasibility of the proposed approach in buildings monitoring is verified.