Concept
The HDL-64E operates by pulsing a laser diode for a short duration (typically 4 nanoseconds) and precisely measuring
the amount of time it takes for the pulse to travel to an object, reflect off and return to a highly sensitive
photodetector. This is called time of flight (TOF) measurement. In practice, Velodyne uses multiple pulses and a
careful analysis of the returns from each pulse, also noting the intensity of the return.
The idea and deployment of TOF systems is not new-if you've ever been caught in a LIDAR speed trap this same
technology was in use. Velodyne's unique contribution to the state-of-the art in sensing comes from its approach
of using multiple emitter/detector pairs and rotating the entire unit.