A review of terrestrial laser scanning (TLS)-based technologies for deformation monitoring in engineering

Terrestrial laser scanning (TLS) has gained prominence as a deformation monitoring technology in various fields such as bridges and tunnels. This paper offers a comprehensive overview of TLS-based deformation monitoring, covering measurement principles, stochastic models, registration, change detection, and practical applications. We systematically classify, detail, and compare methods for change detection, registration, and georeferencing, shedding light on their strengths, weaknesses, and applicability. The paper also provides an extensive comparison of deformation detection techniques for structures like bridges and tunnels, as well as ground deformation in landslides and unstable rock masses. Challenges related to achieving high-precision, reliable, and efficient deformation monitoring are discussed, and avenues for future research are outlined. Emphasis is placed on the importance of measurement planning to ensure data accuracy and support informed decision-making, particularly for large or spatially constrained structures. Future research should explore leveraging geometric constraints for more accurate change detection and enhancing deformation analysis reliability.