Flash Vs. Scan
A LiDAR system can observe the complete field of view (FOV) at once, called Flash systems. Flash typically works well for short to mid-range (0-100m), and by capturing the complete scene at once also objects with high relative speeds can be detected properly. Another implementation is to focus on a subset of the FOV, consequentially look at the next subsets, until the complete FOV is covered, called Scanning. Scanning can focus the light on the subset instead of the full FOV, and therefore can do object detection at a longer range compared to Flash.
