Lidar (also called LIDAR, LiDAR, and LADAR) is a sensor that measures distance to a target by illuminating the target with a laser light and measures the reflected pulses with appropriate data acquisition electronics. To form a 3D image, either multiple beams of light can be rotated with the corresponding receiver and data acquisition circuitry generating the point cloud data, or a single beam can be swept across the scene at very high speed. The latter is generally used for Lidar that capture only a window of scene data ahead of the sensor.