LaserScanners

Laserscanners, also called laser scanners, are devices that capture the three-dimensional geometry of a scene by projecting laser light and measuring the distance to surfaces. Most systems determine distance by either time-of-flight, where the travel time of a released laser pulse is measured, or phase shift, where the phase difference between emitted and received light is used. Some devices use triangulation or structured light. Collecting a sequence of distance measurements as the scanner sweeps the scene yields a 3D point cloud. Color information can be captured by a co-registered camera and mapped onto the points.

Types include terrestrial (static or handheld), mobile (mounted on a vehicle), and airborne systems (lidar). Line scanners collect data along a line, while 3D scanners acquire dense data by rotating around the scene. Range can extend from a few meters to hundreds of meters, with accuracies from millimeters in high-end terrestrial scanners to centimeters elsewhere.

Outputs: point clouds, meshes, and textures; common file formats include LAS/LAZ, PLY, OBJ, E57. Scanners are used in architecture, engineering, construction, surveying, archaeology, cultural heritage, robotics, manufacturing inspection, and autonomous navigation.

Limitations: performance depends on surface properties; transparent, reflective, or dark materials may cause errors. Ambient light, weather, and occlusions can reduce data quality. Registration of multiple scans requires alignment; software may use iterative closest point (ICP) algorithms or SLAM. Practical use requires calibration and proper scanning strategy.

Safety and standards: many scanners are eye-safe (Class 1 or Class 1M) at typical operating ranges, but some configurations may require safety precautions. Data quality depends on scanner specifications and operator technique.