Lasers are widely used in the detection field, with rich technical content and obvious impact on social production and life. Laser ranging is one of the earliest applications of lasers. The principle and application of laser ranging sensor is also a concern of many people. The laser measuring principle is a non-contact measuring principle. This type of sensor is particularly suitable for measuring rapid displacement changes without exerting an external force on the measured object. Non-contact measurement is of great significance for applications where contact is not allowed on the surface to be measured, or for applications that require a long sensor life.
Working principle of laser ranging sensor
When the transit time laser sensor works, the laser diode is aimed at the target to emit laser pulses. After being reflected by the target, the laser light is scattered in all directions. Part of the scattered light returns to the sensor receiver, where it is picked up by the optical system and imaged onto the avalanche photodiode. An avalanche photodiode is an optical sensor with an internal amplification function, so it can detect extremely weak light signals. The distance to the target can be determined by recording and processing the time elapsed from when the light pulse is sent to when it is received back. Transit time Laser sensors must measure transit time extremely precisely because the speed of light is so fast.
Application of laser ranging sensor
Car Collision Avoidance Detector: Generally speaking, most existing car collision prevention system laser ranging sensors use a laser beam in a non-contact manner to identify the distance between the target car in the front or rear situation, when the car When the distance is less than the predetermined safe distance, the car anti-collision system will make emergency braking to the car, or send an alarm to the driver, or make an instant judgment and response to the car driving based on the target car speed, car distance, car braking distance, response time, etc. It can greatly reduce driving accidents. When used on the highway, its advantages are more obvious.
Traffic flow monitoring: The use method is generally fixed to the gantry of high-speed or important intersections, the laser emission and reception are perpendicular to the ground, aiming at the middle of a lane. When there are vehicles passing through, the laser ranging sensor can output the measured data in real time. The relative change value of the obtained distance value, and then the outline of the measured vehicle is depicted. This measurement method generally uses a ranging range of less than 30 meters, and requires a relatively high laser ranging rate, generally requiring 100 Hz. This can achieve good results for monitoring in important road sections, and can distinguish various models. The sampling rate of the vehicle height scan can reach 10 cm per point (at 40Km/h, the sampling rate is 11 cm per point). It can distinguish the height limit, length limit, vehicle type, etc. of traffic flow in real time, and can quickly output the results.
Principle and Application of Gauging Meter Laser Module
2022 08/26