LiDAR means light detection and ranging. Thousands to millions of range measurements per second build a point cloud, a set of 3D dots that outlines walls, shelves, people and vehicles. Because it measures distance directly, it works in darkness and does not care about texture, unlike a normal camera.
Flat 2D scanners sweep one horizontal plane and are the classic safety sensor on AGVs and mobile robots; safety-rated versions stop the vehicle when someone enters a defined protective field. 3D units, either spinning or solid state, are used on autonomous vehicles and for mapping.
Weaknesses: glass and shiny surfaces reflect badly, heavy rain, dust and fog scatter the beam, and high-resolution units are still comparatively expensive.
