Lidar can be divided into wire beams from multi-wire laser pointer radars, which are mainly used in the automotive industry. There are 16-wire, 32-wire and 64-wire laser radars. If divided systematically, there are mainly direct detection lidar and coherent detection lidar. In fact, what we have mentioned so far, including lidar used in autonomous driving, robotics, and mapping, basically belong to this type of direct detection lidar.
Some special radars, such as wind and speed sensors, usually adopt a coherent system. According to application classification, we can divide more, such as: laser rangefinder, laser three-dimensional imaging radar, laser speed radar, laser atmospheric detection radar, and so on. According to the principle of distance measurement, there are two ways: 1. One is TOF technology, which is Time of Flight. It is a way to make time measurements of light flight. In this way, as the name implies, a laser is emitted, and then a diode is used for laser echo detection.
We then use a very high-precision timer to measure the time difference between the light wave emitted to the target and the feedback that comes back. However, we all know that the speed of light in the green laser pointer is constant, and the time difference can be multiplied to obtain the distance of the target. 2. There is another brand-new measuring method-triangle ranging method. Like the somatosensory cameras we can hear, triangulation is also used.