Light Detection and Ranging (LIDAR) is a ranging technique that typically uses the Time-of-Flight (ToF) of emitted, reflected and detected light. LIDAR does not require infrastructure to be installed on the remote object. LIDARs operate by “scanning” the environment to generate a 2D or 3D geometric and, in some cases, visual representation of the environment.
Working Principles
ToF-based LIDAR emit focused beams of light energy in a specific direction; the light is reflected from surfaces in the environment and detected by detectors within the LIDAR sensor. LIDARs typically operate in the near infrared light spectrum, which is not observable by humans. Scanning is performed by rotating mirrors or by rotating the actual emitter and detector in the LIDAR sensor. 3D scanning is performed by rotating the emitter and detector in different axes or by using multiple emitter and detector pairs. As a LIDAR scans an environment, they create a geometric (range-based) and visual (intensity-based) representation of the environment.
The visual and geometric data produced by LIDARs are known as point clouds. Proximity Detection Systems (PDS) need to process the point cloud data to detect, classify and track remote objects.
Advantages
- No infrastructure is required on remote objects (reflective markers may be used to enhance performance)
- Does not rely on external infrastructure
- Most LIDARs can scan the environment with a large (up to 360 degree) Field-of-View (FOV)
- Relatively accurate ranging performance
- Suitable for both surface and underground applications
Limitations
- Most LIDARs are likely to be affected by harsh environmental conditions
- The performance of LIDAR depends on the material properties of the surfaces in the scene
- LIDAR sensors may require additional maintenance to clear dirt and other debris from their lenses
- Detection, classification and tracking, in some cases, can be computationally expensive
- Detection of a remote object requires Line-of-Sight