DEPHOS Group were probably the first company in Poland to use a terrestrial laser scanning system on its projects. Mounted on a survey tripod, a terrestrial laser scanning system uses a laser that emits up to 2 millions of light pulses per second. These are distributed across the scene using the combination of a spinning mirror and a motorized head unit. The time taken for each pulse to hit a surface in the scene and be reflected to the scanning system is measured and a 3D coordinate for the location of that point relative to the scanner is computed.
This mechanism produces a point cloud, typically in 360-degrees around the scanner. To collect data on all sides of the objects in a scene, the scanner is moved to different scan positions to collect a series of overlapping point clouds. These point clouds are aligned to produce one consistent point cloud of the site, which is then used as the base 3D survey dataset of subsequent modelling applications.
Terrestrial laser scanners are used to collect point clouds of both the interior and exterior detail of buildings, engineered structures, rock slope monitoring or calculating the volume of quarries and open-pit mines. DEPHOS Group is well known for its work applying terrestrial laser scanning to heritage preservation projects.