LiDAR

Lidar is a method for determining ranges (variable distance) by targeting an object with a laser and measuring the time for the reflected light to return to the receiver. LiDAR is an active remote sensing system – the system itself generates energy – in this case, light – to measure things on the ground. In a LiDAR system, light is emitted from a rapidly firing laser.  This light travels to the ground and reflects off of objects. The reflected light energy then returns to the LiDAR sensor where it is recorded.

https://en.wikipedia.org/wiki/Lidar https://www.neonscience.org/resources/learning-hub/tutorials/lidar-basics

https://www.neonscience.org/resources/learning-hub/tutorials/lidar-basics