LiDAR

A sensor that fires lasers and times their return to measure distance, scanning out a 3D point cloud of its surroundings.

Lidar sends out laser pulses and measures how long the light takes to bounce off an object and return, computing distance from that time; rotating or scanning the beam then covers a wide field of view, producing a 3D point cloud of the surroundings. The first system of this kind was built by Hughes Aircraft Company in 1961, shortly after the laser was invented. Lidar comes in three basic designs: fully mechanical units that spin the whole sensor, semi-solid-state units that scan with a rotating mirror or a MEMS micro-mirror, and solid-state units with no moving parts at all; by beam count, it's either a 2D single-line unit that scans a single plane or a multi-line 3D unit. Compared with a depth camera, lidar measures farther, is more accurate at range, and is less affected by ambient light, so it keeps working reliably outdoors in direct sunlight, though its points are sparser, carry no color, and cost more. On robots it is used mainly for SLAM mapping and localization, navigation and obstacle avoidance, and terrain sensing, and is common on self-driving cars, quadrupeds, and humanoids.

ExampleThe Livox Mid-360 is a common 3D lidar on mobile robots, with a 360° horizontal and 59° vertical field of view; it can measure a target with 10% reflectivity out to 40 meters, with a minimum range of 0.1 meters.

Also called

Light Detection and Ranging, Laser Scanner, 3D LiDAR

Related

Point Cloud · LiDAR Channels · Solid-State LiDAR · LiDAR SLAM · Time of Flight · Livox Mid-360

Sources

Wikipedia: Lidar
Livox Mid-360 产品页 (Chinese)