Insights of TLS-MLS Current Technology and Foresight for Future Development and Applications

This paper presents a critical overview of commercial solutions for terrestrial laser scanning (TLS) and portable mobile laser scanning (MLS). A review of current technology is reported, with emphasis on some key functions implemented in the latest-generation sensors. In the case of TLS, evidence is given to platforms for data sharing during acquisition, the support to the construction sector, the HDR imaging, the multiple georeferencing options, the enhancement of point-cloud quality, and the integration between range-measurement techniques. In the case of MLS, the highlight is on the contribution of AI, the imaging solutions, the development of long-range sensors, and the solutions for forestry. The paper also discusses the technology foresight, including aspects such as scan planning, accuracy evaluation, the growing use of AI in data processing, and the development of multispectral LiDAR for terrestrial platforms. A case study involving a complex historical building enables the assessment of both metric and operational performance of TLS and MLS approaches, highlighting strengths and limitations under specific survey conditions.