LiDAR

LiDAR fires invisible laser light in every direction very quickly, and calculates distance from the time it takes to hit an object and come back. Gather the many points measured this way, and the cars, people and buildings around you appear as three-dimensional shapes.

Its strength is that it measures distance accurately even on a dark night. In return, it costs more than a camera, and its performance drops in heavy rain or fog. In self-driving, one side has long argued that LiDAR is a must, while the other says cameras and AI are enough.

It is similar to how a bat knows the distance to a wall from the echo of its own sound coming back. LiDAR uses light instead of sound.

It is the key to understanding why each self-driving car company has a different sensor setup. It is also widely used in robot vacuums, logistics robots, drones and map making.