safety laser scanners how they work, many people are not very clear, here I give a case
Generally, in order to count the vehicles passing through the highway bayonet within a certain period of time, it is necessary to make accurate judgments on passing vehicles, which is a test of the accuracy of the detection products. In the past, everyone was not familiar with the application of safety laser scanners in traffic flow statistics. We can understand through a practical case.
Practical application case
Figure 1 outdoor safety laser scanner
Installation real picture (shared from real customers)
working principle
Install the safety laser sensor directly above the lane to make it detect vertically downwards, as shown in Figure 1.
When no vehicle is passing by, the distance from the safety laser sensor to the ground is detected, which is assumed to be X
When a vehicle passes under the safety laser sensor, the distance from the safety laser sensor to the top of the vehicle is detected, which is assumed to be Z
The value of X must be greater than the value of Z. At this time, it can be distinguished from the data whether there are vehicles passing by, so as to cooperate with the system to realize the statistics of traffic flow.
In addition, according to the difference of the Z value, the lidar can also cooperate with the system to determine the height of the vehicle, so as to roughly realize the judgment of the size of the car.
Figure 2 Safety laser sensor host computer interface illustration
It is worth mentioning that the 2d lidar sensors can not only count the traffic flow, but also trigger the camera to take pictures.
Figure 3 The laser scanner detects that the vehicle has passed once and can trigger the camera to take pictures
Ranging principle
2D safety laser scanner applications, based on TOF (Time-of-Flight), the principle of time-of-flight, adopts the phase method to realize the ranging function. Specifically, safety laser scanner technology emits modulated near-infrared light, which is reflected after encountering an object. The sensor calculates the phase difference between the emission and reflection of the modulated infrared light to convert the distance to the measured target object to generate depth Information (refer to the following schematic diagram of ranging principle)
Figure 5 Another installation method of lidar with statistical traffic flow
Efficient and stable
Lidar can operate efficiently all-weather with strong stability
High accuracy
Through the self-developed self-adaptive algorithm of the lidar, the accuracy rate of traffic statistics reaches 99%
Simple operation and easy integration
Lidar is easy to operate, easy to integrate into the system to collect data
Actual application products
The low cost safety laser scanner used by the customer for traffic statistics is a TOF single-point ranging laser scanner that Cyndar has already mass-produced, with a range of up to 5m/20m and more stable ranging performance. The shell material is made of high-strength anti-corrosion material, which improves the adaptability to the harsh outdoor environment. At the same time, combined with innovative production technology and multiple optimizations of software and hardware, the multi-zone safety laser scanner has truly reached the consumer level, occupying the safety laser scanner market.
Figure 6 Laser TF02 single-point ranging laser scanner product actual picture
