Lidar is a kind of high-precision, high-resolution and high-reliability measurement equipment, which is widely used in the fields of automatic driving, terrain measurement, industrial inspection and so on. This article will briefly describe the structure, principle, classification and characteristics of LiDAR.
I. Structure of LiDAR
LiDAR is usually composed of laser, optical system, control system, receiver, signal processor and so on.
1, laser: laser is the core component of LIDAR, usually using semiconductor lasers or solid-state lasers, capable of transmitting high-power, high-frequency laser beams.
2, optical system: the optical system includes the transmitting optical system and receiving optical system. The transmitting optical system is responsible for focusing the laser beam into a fine beam so that the laser beam is precisely directed to the target object. The receiving optical system is responsible for collecting the laser signal reflected back from the target object and converting it into an electrical signal.
3, control system: the control system is the intelligent core of LIDAR, responsible for controlling the transmission and reception of the laser, as well as the focusing and scanning of the laser beam.
4, receiver: the receiver is another core component of LIDAR, responsible for receiving laser signals reflected back from the target object and converting them into electrical signals. The performance of the receiver directly affects the accuracy and resolution of LIDAR.
5, signal processor: the signal processor is responsible for processing and analyzing the received laser signals, extracting the target object's position, distance, speed and other information, and transferring it to the control system for the next step.
Two, the principle of LIDAR
The principle of LIDAR is to use the interaction between the laser beam and the target object to determine the position, distance, speed and other information of the target object by measuring the reflection or scattering of the laser beam.
When a laser beam is directed at a target object, part of the laser beam is absorbed by the target object and part of the laser beam is reflected or scattered by the target object. After the receiver collects the reflected or scattered laser signals, the distance and speed of the target object can be determined by calculating the propagation time and speed of the laser beam.
At the same time, by analyzing the reflected or scattered characteristics of the laser beam, the position, shape and other information of the target object can be determined.
Three, the classification of LiDAR
LiDAR can be categorized according to the type of laser used, scanning method, working principle and other ways. The following is a common classification:
1, laser type: according to the different types of lasers, LiDAR can be divided into solid LiDAR and semiconductor LiDAR. Solid LIDAR usually uses solid material as the laser medium, with high power, high frequency and other advantages; semiconductor LIDAR usually uses semiconductor material as the laser medium, with small size, low power consumption and other advantages.
2, scanning mode: according to the different scanning mode, LIDAR can be divided into mechanical scanning LIDAR and solid-state scanning LIDAR.
Mechanical scanning LIDAR usually use rotating lenses or rotating prisms and other mechanical structures for scanning, with a large scanning range, high reliability and other advantages; solid-state scanning LIDAR usually use electronic scanning or optical scanning and other technologies for scanning, with high speed, high accuracy and other advantages.
3, working principle: according to the different working principles, LIDAR can be divided into pulsed LIDAR and continuous wave LIDAR. Pulsed LiDAR usually uses short pulse laser for measurement, with high precision, high resolution and other advantages; continuous wave LiDAR usually uses continuous wave laser for measurement, with high speed, high reliability and other advantages.
Four, the characteristics of LiDAR
LiDAR has the following characteristics:
1, high precision: LiDAR has a high-precision measurement capability, can achieve sub-millimeter level measurement accuracy.
2, high resolution: LiDAR has the ability of high resolution, can realize sub-centimeter level resolution.
3, high reliability: LiDAR has the characteristics of high reliability, can work stably in harsh environments.
4, a large amount of data: LiDAR can quickly collect a large number of three-dimensional data, for the subsequent data processing and analysis provides a wealth of data support.
5, easy to integrate: LiDAR can be integrated with other sensors, controllers and other equipment to achieve multi-sensor information fusion.
Laser radar's role
1, auxiliary car planning line
Laser radar in the auxiliary car planning line plays an important role, it can autonomously plan the route, control the car to reach the intended target, but also according to the laser encountered an obstacle after the turn time to measure the target and their own distance, helping the vehicle recognition system to better recognize the street.
2, assisted driving safety
Lidar plays an important role in assisted driving safety. It can assume redundancy to achieve a higher level of safety, especially under the influence of bright light, LiDAR can provide a more accurate perception of the ability to provide more comprehensive security for assisted driving. In addition, LiDAR can assist cars in avoiding obstacles and provide more accurate driving path planning and navigation information.
Through the use of LiDAR, the functions of an autonomous driving system can be realized, providing drivers with a safer and more efficient travel experience.
3. Sensing the external environment
LIDAR emits laser beams and converts them into electrical signals, which are then processed by computers to obtain images, sounds and other information about the external environment.
In this way, LIDAR can sense the changes in the external environment, such as the condition of the road, the position of pedestrians and so on. In this way, we can use LiDAR to predict and deal with these changes, so as to better cope with traffic, safety and other issues.