Automated Building Monitoring System Based on Reflectorless Measurements: A Case Study of the IMSGeo System

Automatic geodetic monitoring systems allow for real-time monitoring of an object's condition. The article presents the IMSGeo system (Intelligent Monitoring System for Threatened Objects based on Automatic Non-invasive Measurements), which meets three fundamental efficiency criteria of a monitoring system: reliability, affordability, and the clarity of interpreted results. In this system, the surface is measured using reflectorless methods, and surface changes are determined based on the analysis of normal vectors. The studies were carried out for five typical surfaces: concrete, expanded polystyrene, tiles, brick, and metal. The experiment included two key aspects: analysis of measurement repeatability within accepted accuracy limits and analysis of geometry change determination using a proprietary algorithm. In the first case, a direct comparison of points was made using threshold alerts depending on the repeatability of the measurement. The differences generally did not exceed 5 mm. In the second case, the results showed that the maximum differences for brick and metal surfaces did not exceed 2 mm. For the polystyrene-covered surface, differences for 89% of measurements did not exceed 2 mm; for the tiled surface, 84% did not exceed 2 mm; and for the concrete surface, 97% did not exceed 5 mm.