LIDAR (Light Detection and Ranging) is a remote sensing method that uses laser light to measure distances to objects. A LIDAR sensor emits rapid laser pulses (often in the near-infrared spectrum) and measures the time it takes for each pulse to bounce off a surface and return (time-of-flight), converting this to distance. By sweeping the laser or using multiple laser beams (in modern 3D LIDAR), the sensor collects a dense set of distance measurements in all directions, forming a point cloud of the environment. In autonomous vehicles, for example, a spinning LIDAR unit on the roof provides a 360-degree 3D scan of the surroundings, which can be used for mapping, object detection, and navigation. LIDAR can provide very accurate 3D information and works in various lighting conditions (including night). However, heavy rain/fog can attenuate the laser. LIDAR data is typically processed with algorithms to cluster points (to find obstacles), or combined with cameras for sensor fusion.