In modern surveying, the general meaning of laser scanning is the controlled deflection of laser beams, visible or invisible. Within the field of 3D object scanning, laser scanning combines controlled steering of laser beams with a laser rangefinder. By taking a distance measurement at every direction the scanner rapidly captures the surface shape of objects, buildings and landscapes. Construction of a full 3D model involves combining multiple surface models obtained from different viewing angles, or of other known constraints. Small objects can be placed on a revolving pedestal, in a technique akin to photogrammetry.
The benefits of Laser Scanning:
• It’s ideal when access is of a limited duration e.g. railway track possession or crime scene.
• Laser scanning can be used where features can be seen but not physically accessed, so a cliff face, retained façade or ceiling details.
• It can be used where complex detail is required, so in historic buildings featuring ornate moulding or structures with complex steel detail.
• It’s ideal in BIM projects where 3D models are required as a deliverable.
• Where night work only is allowed, laser scanning can be used in the dark.
• Comprehensive data collection allows desktop studies using the point cloud information and can improve decision making without return site visits.