CN209821384U

CN209821384U - Range finding alarm device based on laser radar

Info

Publication number: CN209821384U
Application number: CN201920363672.7U
Authority: CN
Inventors: 陈浩; 韩雪非; 周玉栋; 罗杰; 陈向成; 杨旭; 胡锦敏
Original assignee: Shenzhen Luchang Science and Technology Co Ltd; Shenzhen Lu Chang Intelligent Technology Co Ltd
Current assignee: Shenzhen Luchang Science and Technology Co Ltd; Shenzhen Lu Chang Intelligent Technology Co Ltd
Priority date: 2019-03-21
Filing date: 2019-03-21
Publication date: 2019-12-20
Anticipated expiration: 2029-03-21

Abstract

The utility model discloses a range finding alarm device based on laser radar, which belongs to the technical field of range finding, comprising a laser radar and an alarm, wherein the laser radar comprises a signal processor, a clock chip, a transmitter for transmitting laser signals to a target object and a laser signal receiver for receiving the laser signals reflected by the target object, and the input end of the signal processor is connected with the output end of the receiver; the signal processor comprises a single-threshold comparator and an automatic gain control unit, the output end of the automatic gain control unit and the clock chip are both connected with the input end of the single-threshold comparator, and the output end of the single-threshold comparator is connected with an alarm. The automatic gain control unit is arranged to eliminate errors caused by inconsistent amplitude, the whole scheme has the advantages of high dynamic range, wide frequency band, no need of complex devices, and high cost and volume.

Description

Range finding alarm device based on laser radar

Technical Field

The utility model relates to a range finding technical field, in particular to range finding alarm device based on laser radar.

Background

With the development of urban traffic, traffic facilities such as overpasses, pedestrian overpasses, tunnels and the like are continuously increased, the traffic capacity of highway traffic is improved, but the road conditions are more complicated, the height and the width of a road are limited, so that traffic accidents such as truck jamming, collision and the like are frequent, and vehicles and drivers are not protected. Although some road signs with limited height and width, various traffic accidents caused by the fact that the actual height and width and the identification are obtained due to maintenance or other temporary events and the uncertainty of the vehicle parameters of the driver cause great personal and property loss.

The traditional photogrammetry method needs various hardware and software such as a high-definition camera and an image processing algorithm, and at present, due to the limitation of a database and the algorithm, a large error exists in the measurement of the size and the distance. The method of visual judgment of the vehicle driver and the like also depends on the experience of the driver and the familiarity of the driver with the road conditions, and certain defects exist.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a laser radar's range finding alarm device to the realization is to the width of measuring vehicle the place ahead road and the accurate measurement of barrier height.

In order to achieve the above purpose, the utility model discloses a range finding alarm device of laser radar, including laser radar and alarm, the laser radar includes signal processor, clock chip, is used for to the transmitter of target object transmission laser signal and is used for receiving the laser signal receiver that the target object reflects back, the input of signal processor is connected with the output of receiver;

the signal processor comprises a single-threshold comparator and an automatic gain control unit, the output end of the automatic gain control unit and the clock chip are both connected with the input end of the single-threshold comparator, and the output end of the single-threshold comparator is connected with an alarm.

Further, an amplifier is arranged between the single threshold comparator and the automatic gain control unit.

Further, the laser radar is an all-solid-state laser radar.

Further, the transmitter comprises a transmitting diode and a first optical lens, the receiver comprises a receiving diode and a second optical lens, the first optical lens is arranged on the path of the transmitting light of the transmitting diode, and the second optical lens is arranged on the path of the laser light reflected back by the target object.

Further, the first optical lens and the second optical lens are both plastic optical lenses.

Further, the deviation of this range finding alarm device installation back and plantago to the axis is within 50mm, and the facula of controlling the passageway is followed down apart from short-range laser radar body horizontal distance and is 6.5m, and the middle channel facula is followed down apart from short-range laser radar body horizontal distance and is 10.5 m.

Compared with the prior art, the utility model discloses there are following technological effect: the utility model discloses a width and the barrier height that set up laser radar real-time detection vehicle the place ahead road to carry out the early warning, remind overrun vehicle driver's safety, also ensured the safety of road setting.

Drawings

The following detailed description of the embodiments of the present invention is made with reference to the accompanying drawings:

FIG. 1 is a schematic structural diagram of a range finding alarm device based on a laser radar;

FIG. 2 is a schematic block diagram of a lidar based range alarm apparatus;

FIG. 3 is a schematic diagram of a prior art signal processor;

fig. 4 is a schematic diagram of a signal processor according to this embodiment;

FIG. 5 is a schematic diagram of a laser radar probe spot;

fig. 6 is a schematic diagram of the lidar detection principle.

Detailed Description

To further illustrate the features of the present invention, please refer to the following detailed description and accompanying drawings. The drawings are for reference and illustration purposes only and are not intended to limit the scope of the present disclosure.

As shown in fig. 1, fig. 2 and fig. 4, the present embodiment discloses a ranging alarm device based on a laser radar, which includes: the laser radar and alarm device 50, the laser radar includes the signal processor 10, the clock chip 20, the launcher 30 used for sending the laser signal to the target object and the laser signal receiver 40 used for receiving the target object and reflecting back, the input end of the signal processor 10 is connected with output end of the receiver 40;

the signal processor 10 comprises a single threshold comparator 11 and an automatic gain control unit 12, an output end of the automatic gain control unit 12 and a clock chip 20 are both connected with an input end of the single threshold comparator 11, and an output end of the single threshold comparator 11 is connected with an alarm 50.

It should be noted that, the emitter emits diode and optical lens, the receiver includes receiving diode and optical lens, the high-precision clock chip provides the flight time timing function for the above-mentioned detection signal, the laser emitting part emits pulse laser, at this moment, the chip starts timing, and the timing stops after the receiving part receives the laser echo signal. The output end of the receiving diode is connected with an automatic gain control unit, the automatic gain control unit adjusts the reflected laser signals, the signals with different amplitudes are adjusted into signals with consistent amplitudes, then the signals enter a single threshold comparator, the reflected signal waveforms are compared with the transmitting signal waveforms, the time difference between transmitting and returning is obtained, and therefore the distance information of the detected object is indirectly obtained, and judgment is given according to the set safety value. And if the detected height and width information of the vehicle does not accord with the preset safety value, immediately triggering an audible and visual alarm to prompt a vehicle driver to pay attention to the road condition information.

It should be noted that the principle OF calculating TIME-OF-FLIGHT (TOF-FLIGHT) in the prior art is to calculate the TIME difference between the reflected signal and the transmitted signal to obtain the TIME OF FLIGHT OF the probe light, thereby indirectly calculating the FLIGHT distance. The most ideal state for calculating TOF is that the information contained in the transmitted signal is related to the detection distance, but not related to other forms of the object to be measured (for example, factors affecting the signal strength), and the conventional method is to use a single threshold comparator to perform digital processing on the reflected signal, and the specific implementation method is shown in fig. 3. The intensity of the reflected signal is different due to different detected distances or different reflectivities of the detected objects, and if Vin1 and Vin2 in fig. 3 are reflected signals of two targets with different reflectivities at the same distance, two time points t1 and t2 are generated when the two signals are compared with the same threshold value due to different intensities, and the difference between the two time points is an error caused by the circuit, and the error needs a large number of algorithms and fitting to be eliminated, so that the post-processing is very complex. In order to eliminate the error from hardware, a constant ratio timing method is adopted in some schemes, but the constant ratio timing method needs complex delay line devices and attenuation devices, and has poor frequency domain applicability, high cost and large volume. As shown in fig. 4, in this embodiment, the automatic gain control unit is arranged to eliminate the error caused by the inconsistent amplitude, so that the whole scheme has high dynamic range, wide frequency band, no need of complex devices, and advantages in cost and volume.

Further, an amplifier 13 is disposed between the automatic gain control unit 12 and the single threshold comparator 11.

Further, the laser radar in this embodiment is an all-solid-state laser radar, and the refractive optical lens is used to shape the light emitted from the laser into a light spot with a certain shape, which covers a predetermined detection field of view and has a certain horizontal and vertical resolution, and the technique does not need to use a scanning structure with a moving element, and thus is purely solid-state, thereby reducing the cost and greatly improving the reliability, and improving the data refresh rate (over 100 Hz).

Further, the receiver comprises a receiving diode and a first optical lens, the first optical lens is arranged on a path of the emitted light of the emitting diode, and the second optical lens is arranged on a path of the laser light reflected by the target object. The first optical lens is a plastic lens with collimation and beam expansion functions, the distribution area of three light spots is shown in figure 5, the middle light spot detects a high obstacle at a short distance, and the light spots at two sides detect a low obstacle and an ultra-wide obstacle; at far distances, the intermediate spot is already spread out and therefore assumes the function of detecting all obstacles.

As the three light spots shown in fig. 5 are distributed in three positions of the detection front view field, the three light spots can distinguish the height, left, middle and right position information (length information of two dimensions) of the detected object in the detection view field, and the detection light spots can also detect the depth information of the detected object in the emission direction, so that the laser radar can simultaneously obtain the length information of the three dimensions of the detected object, and the information can be used for simple height and width and position budget of the obstacle for discriminating the type of the obstacle.

Furthermore, the first optical lens and the second optical lens are plastic optical lenses made of PC materials, so that the cost can be greatly reduced while the performance is ensured.

Further, as shown in fig. 6, the deviation between the distance measurement alarm device and the vehicle front axis is within ± 50mm after installation, the horizontal distance between the lower edge of the light spot of the left channel and the lower edge of the light spot of the right channel and the short-distance laser radar body is 6.5m, and the horizontal distance between the lower edge of the light spot of the middle channel and the short-distance laser radar body is 10.5 m. According to the arrangement, the laser radar can achieve a better field angle and a better detection direction; the short-range laser radar range finder transmits laser signals which accord with the Class 1M laser of human eye safety level and returns the detected distance information in real time.

Further, the alarm in this embodiment is an audible and visual alarm, and the signal processor determines the detected distance to the obstacle and a set safety value, and if the detected height and width information of the vehicle do not meet the preset safety value, the audible and visual alarm is immediately triggered to give an alarm to prompt the driver of the vehicle to pay attention to the road condition information.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. The utility model provides a range finding alarm device based on laser radar which characterized in that includes: the laser radar comprises a signal processor, a clock chip, a transmitter and a laser signal receiver, wherein the transmitter is used for transmitting laser signals to a target object, the laser signal receiver is used for receiving the laser signals reflected by the target object, and the input end of the signal processor is connected with the output end of the receiver;

2. The lidar-based range finder alarm apparatus of claim 1, wherein an amplifier is further disposed between said single threshold comparator and said automatic gain control unit.

3. The lidar-based range finder alarm apparatus of claim 1, wherein said lidar is an all-solid-state lidar.

4. The lidar-based range finder alarm device of claim 3, wherein said transmitter comprises a transmitting diode and a first optical lens, and said receiver comprises a receiving diode and a second optical lens, the first optical lens being disposed in the path of the transmitted light from the transmitting diode and the second optical lens being disposed in the path of the laser light reflected back from said target object.

5. The lidar-based range finder alarm device of claim 4, wherein said first and second optical lenses are plastic optical lenses.

6. A lidar based range finding alarm device according to any one of claims 1 to 5, wherein the range finding alarm device is mounted within ± 50mm from the vehicle front direction axis, the horizontal distance from the lower edge of the light spot of the left and right channels to the short range lidar body is 6.5m, and the horizontal distance from the lower edge of the light spot of the middle channel to the short range lidar body is 10.5 m.