Intelligent laser radar optical path calibration system based on image recognition

Abstract

The invention relates to the technical field of laser radars, and discloses a laser radar light path intelligent calibration system based on image recognition, which comprises a laser transmitter used for transmitting laser and a reflector used for reflecting the laser transmitted by the laser transmitter. The laser radar light path intelligent calibration system based on image identification can identify and compare the position of a light spot in a reference image on a reflector and the position of a light spot in a real-time image on the reflector through an image identification unit, determine the offset of the positions of the light spots in the two images and judge whether the offset is greater than a set threshold value or not; therefore, whether the position of the light path needs to be calibrated and adjusted or not is judged on the basis, the calibration and adjustment basis can be prevented from being influenced by the change of the atmospheric environment during collection, the accuracy of the obtained calibration and adjustment basis is ensured, the misjudgment rate is effectively reduced, and the calibration reliability and accuracy of the intelligent calibration system for the light path are improved.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and in particular to an intelligent laser radar optical path calibration system based on image recognition. Background Art

[0002] Portable aerosol lidar is mainly used to monitor aerosol concentration, particle distribution and real-time tracking of pollution sources in the atmosphere. This device is based on the principle of laser scattering. It analyzes physical elements in the atmosphere, such as aerosol concentration and particle size, by emitting laser pulses and receiving signals scattered back by aerosols and other components. Therefore, it is increasingly used in environmental protection, meteorology and transportation fields.

[0003] The main application scenarios of portable aerosol lidar are the 24-hour unattended state of fixed-point radar scanning and the vehicle-mounted mobile navigation state. Since the radar is in motion in the above two application scenarios, the optical path of the lidar will be offset by the vibration during the movement, affecting the accuracy of the detection data. Therefore, lidar optical path calibration is very important for the detection performance of lidar. In order to ensure the accuracy of the data detected by the portable aerosol lidar, it is necessary to timely detect the optical path of the lidar and make timely optical path alignment adjustments after determining that the optical path is offset.

[0004] The existing optical path automatic alignment system transmits by emitting laser from a light source into the atmosphere. The echo signal generated by the interaction between the laser and the atmosphere is collected and analyzed by the signal collection and analysis system of the laser radar. If it is determined according to the analysis result that the optical path of the transceiver system is not the best, a corresponding adjustment action will be made to adjust the direction of the emitted laser, that is, through continuous "judgment-adjustment-re-judgment-re-adjustment" repeated operations until the best is reached. However, the above-mentioned optical path automatic alignment system uses a signal judgment system to judge whether the echo signal is the best. However, the atmospheric echo signal in a clear and clean weather is completely different from the atmospheric echo signal in heavily polluted weather. Therefore, the judgment of the echo signal as the basis for adjustment is often affected by changes in the atmospheric environment and misjudgment occurs. At the same time, the specific optical path offset status cannot be obtained by judging whether the echo signal is the best, so it is impossible to quickly determine in which direction the optical path needs to be adjusted and the amount of adjustment, which leads to low adjustment efficiency. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a laser radar optical path intelligent calibration system based on image recognition, which solves the problems mentioned in the above background.

[0006] The present invention provides the following technical solution: a laser radar optical path intelligent calibration system based on image recognition, comprising:

[0007] A laser transmitter, used for emitting laser;

[0008] A reflector, used for reflecting the laser emitted by the laser transmitter;

[0009] A telescope, used to send the laser reflected by the reflector to the detection area;

[0010] An optical path image acquisition unit, used to photograph the laser emission direction and acquire an image of the laser emission direction;

[0011] An image recognition unit, used to identify and analyze the laser emission direction image;

[0012] A motion control unit, used for adjusting the position of the reflector;

[0013] The echo acquisition and analysis unit is used to collect and analyze the signals scattered back by aerosols and other components in the atmosphere after the laser emitted by the telescope irradiates the atmosphere of the detection area, and is connected to the micro control unit;

[0014] The microcontroller unit is used to receive control instructions and issue execution instructions.

[0015] Preferably, the image recognition unit recognizes and analyzes the laser emission direction image by comparing the real-time laser irradiation position image with the reference irradiation position image taken in advance to determine whether the optical path is seriously offset.

[0016] Preferably, the laser irradiation position image is an image of the position of the light spot formed by the laser irradiation on the reflector. The advantage of this arrangement is that the image of the position of the light spot formed by the laser irradiation on the reflector is used as the basis for judging the degree of optical path deviation, thereby avoiding interference caused by changes in the atmospheric environment, thereby avoiding misjudgment problems when automatically detecting the laser optical path deviation condition, and effectively improving the accuracy of the calibration work of the optical path intelligent calibration system.

[0017] Preferably, the optical path image acquisition unit is a high-definition camera, which can be used to capture the laser irradiation position image as the spot position formed by the laser irradiation on the reflector to form a clear image. The optical path image acquisition unit is connected to the image recognition unit. The advantage of such a setting is that a clear spot position image can be obtained, thereby facilitating the subsequent recognition and analysis work of the image recognition unit, and further improving the accuracy and reliability of the calibration work of the optical path intelligent calibration system.

[0018] Preferably, the reference image of the laser irradiation direction is acquired by irradiating the laser onto a reflector which is at an angle of forty-five degrees to the laser direction through a laser transmitter, and the optical axis direction of the telescope is perpendicular to the laser irradiation direction, and then the image recognition unit acquires the image of the spot position formed by the laser on the reflector at this time, which is the required reference image of the laser irradiation direction. The advantage of such a setting is that it can ensure that the laser irradiation direction reflected by the reflector is perpendicular to the optical axis direction of the telescope, thereby ensuring that the laser radar can reliably perform detection work.

[0019] Preferably, when obtaining the reference image of the laser irradiation direction, the irradiation direction of the laser after being reflected by a reflector with an inclination of forty-five degrees is vertically toward the sky, and the signal scattered back from a height of three kilometers is collected and analyzed by the echo signal collection and analysis unit. When the signal-to-noise ratio of the echo signal reaches the best, the spot position image formed by the laser irradiation on the reflector can be used as the reference image of the laser irradiation direction. The advantage of such a setting is that it ensures the acquisition of the clearest and most reliable reference image of the laser irradiation direction, thereby providing the best comparison basis for the subsequent optical path deviation degree, which greatly improves the accuracy and reliability of the calibration work of the optical path intelligent calibration system.

[0020] Preferably, the motion control unit is composed of an optical motion component and a motion control unit circuit module, and the motion control unit is connected to a micro control unit. The advantage of such an arrangement is that the position of the reflector can be adjusted timely and accurately through the optical motion component by the micro control unit and the motion control unit circuit module, thereby ensuring the speed and accuracy of the optical path position adjustment and improving the calibration efficiency and reliability of the optical path intelligent calibration system.

[0021] Preferably, the motion control unit can adjust the horizontal and vertical positions of the reflector. The advantage of such a setting is that the real-time light spot position on the reflector can be quickly and accurately adjusted to a position consistent with the light path position in the reference image, effectively improving the reliability of the light path intelligent calibration system.

[0022] Preferably, the image recognition unit is an image recognition comparison algorithm, and the image recognition unit is connected to a microcontroller unit. The advantage of such a setting is that it can accurately and effectively compare and determine the reference image and the implementation image, ensuring that the optical path position can be accurately adjusted, thereby ensuring the accuracy and reliability of the optical path intelligent calibration system.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The laser radar optical path intelligent calibration system based on image recognition uses an image recognition unit to identify and compare the position of the light spot on the reflector in the reference image and the position of the light spot on the reflector in the real-time image, and determines the offset of the light spot position in the two images and judges whether the offset is greater than the set threshold, so as to judge whether the optical path position needs to be calibrated and adjusted based on this. In this way, the basis for calibration adjustment can be avoided from being affected by changes in the atmospheric environment during collection, thereby ensuring the accuracy of the obtained calibration adjustment basis, thereby effectively reducing the misjudgment rate and improving the calibration reliability and accuracy of the optical path intelligent calibration system.

[0025] 2. The laser radar optical path intelligent calibration system based on image recognition is equipped with a motion control unit, which is composed of optical motion components and motion control unit circuit modules, and the motion control unit is connected to the micro control unit. In this way, the position of the reflector can be adjusted timely and accurately through the optical motion components, thereby ensuring the speed and accuracy of the optical path position adjustment and improving the calibration efficiency and reliability of the optical path intelligent calibration system.

[0026] 3. The laser radar optical path intelligent calibration system based on image recognition can obtain clear light spot position images through the high-definition camera, thereby facilitating the recognition and analysis work of the subsequent image recognition unit, and further improving the accuracy and reliability of the calibration work of the optical path intelligent calibration system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A structural diagram of the laser radar optical path intelligent calibration system based on image recognition provided by the present invention;

[0028] Figure 2 A flowchart of the laser radar optical path intelligent calibration system based on image recognition provided by the present invention;

[0029] Figure 3 A control circuit diagram of a motion control unit circuit module provided by the present invention;

[0030] Figure 4 The piezoelectric sensor driver chip and supporting circuit diagram provided by the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] See also Figure 1-Figure 4 , a laser radar optical path intelligent calibration system based on image recognition, comprising:

[0033] A laser transmitter, used for emitting laser;

[0034] A reflector, used for reflecting the laser emitted by the laser transmitter;

[0035] A telescope, used to send the laser reflected by the reflector to the detection area;

[0036] An optical path image acquisition unit, used to photograph the laser emission direction and acquire an image of the laser emission direction;

[0037] An image recognition unit, used to identify and analyze the laser emission direction image;

[0038] A motion control unit, used for adjusting the position of the reflector;

[0039] The echo acquisition and analysis unit is used to collect and analyze the signals scattered back by aerosols and other components in the atmosphere after the laser emitted by the telescope irradiates the atmosphere of the detection area, and is connected to the micro control unit;

[0040] Microcontroller unit, also called MCU, is used to receive control instructions and issue execution instructions.

[0041] Preferably, the microcontroller unit selects the mature, inexpensive and stable stm32F103 series controller.

[0042] The image recognition unit recognizes and analyzes the laser emission direction image by comparing the real-time laser irradiation position image with the reference irradiation position image taken in advance to determine whether the optical path is seriously offset.

[0043] The laser irradiation position image is an image of the position of the light spot formed by the laser irradiation on the reflector.

[0044] Specifically, using the image of the position of the light spot formed by the laser irradiation on the reflector as the basis for judging the degree of optical path deviation can avoid the interference caused by changes in the atmospheric environment, thereby avoiding misjudgment problems when automatically detecting the laser optical path deviation condition, thereby effectively improving the accuracy of the calibration work of the optical path intelligent calibration system.

[0045] The optical path image acquisition unit is a high-definition camera, which can be used to capture the laser irradiation position image as the spot position formed by the laser irradiation on the reflector to form a clear image. The optical path image acquisition unit is connected to the image recognition unit.

[0046] Specifically, a clear light spot position image can be obtained, thereby facilitating the subsequent recognition and analysis work of the image recognition unit, and further improving the accuracy and reliability of the calibration work of the optical path intelligent calibration system.

[0047] The reference image of the laser irradiation direction is obtained by irradiating the laser onto a reflector at a 45-degree angle to the laser direction through a laser transmitter, and the optical axis direction of the telescope is perpendicular to the laser irradiation direction, and then the image recognition unit is used to obtain the image of the spot position formed by the laser on the reflector at this time, which is the required reference image of the laser irradiation direction;

[0048] Furthermore, the acquisition of the reference image needs to be completed at night, in a dry environment with excellent air quality. Preferably, the air humidity is less than 30%, and preferably, the PM10 is less than 50ug / m3. This can further reduce the interference of other components in the atmosphere, making the acquired reference image clearer and more reliable, ensuring that the subsequent comparison with the real-time image can be carried out accurately and reliably, thereby further improving the accuracy and reliability of the calibration work of the optical path intelligent calibration system.

[0049] Specifically, it can ensure that the irradiation direction of the laser reflected by the reflector is perpendicular to the optical axis direction of the telescope, thereby ensuring that the laser radar can perform detection work reliably.

[0050] Among them, when obtaining the reference image of the laser irradiation direction, the irradiation direction of the laser after being reflected by a reflector with an inclination of forty-five degrees is vertically toward the sky, and the signal scattered back from a height of three kilometers is collected and analyzed by the echo signal collection and analysis unit. When the signal-to-noise ratio of the echo signal reaches the best, the spot position image formed by the laser irradiation on the reflector can be used as the reference image of the laser irradiation direction.

[0051] Specifically, it ensures that the clearest and most reliable reference image of the laser irradiation direction is obtained, thereby providing the best comparison basis for the subsequent optical path deviation degree, greatly improving the accuracy and reliability of the calibration work of the optical path intelligent calibration system.

[0052] See also Figure 3 The motion control unit is composed of an optical motion component and a motion control unit circuit module, and the motion control unit is connected to a micro control unit.

[0053] Specifically, the position of the reflector can be adjusted timely and accurately through the optical motion components by the micro control unit and the motion control unit circuit module, thereby ensuring the speed and accuracy of the optical path position adjustment and improving the calibration efficiency and reliability of the optical path intelligent calibration system.

[0054] Wherein, the motion control unit is capable of adjusting the horizontal and vertical positions of the reflector.

[0055] Specifically, the real-time spot position on the reflector can be quickly and accurately adjusted to a position consistent with the light path position in the reference image, effectively improving the reliability of the light path intelligent calibration system;

[0056] The optical motion component includes a piezoelectric inertial driver, the output end of the piezoelectric inertial driver is connected to an adjustment frame, the adjustment frame is connected to a movable part, and the reflector is installed on the movable part, so that when the microprocessor unit transmits the current laser position offset direction and offset calculated by the image recognition unit to the motion control unit, the motion control unit will control the two piezoelectric inertial drivers to make corresponding motion displacements, thereby driving the adjustment frame to move and cooperating with the movable part to drive the reflector to move to adjust the position of the laser spot on the reflector, thereby realizing fast and accurate optical path calibration, thereby improving the calibration efficiency and reliability of the optical path intelligent calibration system;

[0057] Specifically, the driver chip determines the corresponding driving signals to A1+, A1-, B1+, and B1- respectively through the signals sent by the three MCUs, SC1 IN2, SC1 ENA, and SC1 IN1, to achieve horizontal adjustment of the reflected laser; the driver chip determines the corresponding driving signals to A2+, A2-, B2+, and B2- respectively through the signals sent by the three MCUs, SC2 IN2, SC2 ENA, and SC2 IN1, to achieve vertical adjustment of the reflected laser. Through adjustment in these two directions, the laser is finally adjusted to the correct position.

[0058] Wherein, the image recognition unit is an image recognition comparison algorithm, and the image recognition unit is connected to a micro control unit.

[0059] Specifically, the reference image and the implementation image can be compared and determined accurately and effectively, ensuring that the optical path position can be accurately adjusted, thereby ensuring the accuracy and reliability of the optical path intelligent calibration system.

[0060] Preferably, the image recognition comparison algorithm adopts a histogram algorithm, specifically a grayscale histogram, so that the light spot positions in the reference image and the real-time image can be compared more reliably, ensuring the accuracy of the calculation of the optical path offset, thereby ensuring the accuracy and reliability of the subsequent optical path calibration adjustment, and ensuring that the laser radar can perform detection work efficiently and reliably.

[0061] Working principle: First, the high-definition camera is controlled to capture the spot position of the current laser spot on the laser 45° reflector, and the reference spot position image is retrieved at the same time. The laser spot coordinate position in the two pictures is identified through the image recognition algorithm, and it is analyzed whether the current spot position deviation is greater than the set threshold. When it is greater than the threshold, the offset direction and offset will be further confirmed. Finally, the image recognition unit will combine the offset direction, that is, the offset data, and send the direction and displacement of the piezoelectric inertial driver to the motion control unit. After the piezoelectric inertial driver moves, the MCU of the piezoelectric inertial driver will control the high-definition camera to capture the spot position of the current laser spot on the laser 45° reflector until the spot offset is less than the set threshold. If the spot offset is less than the set threshold, wait for the next set time and then control the camera to capture the laser spot position, and then make a comparison and judgment.

[0062] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A laser radar optical path intelligent calibration system based on image recognition, characterized in that: include: A laser transmitter, used for emitting laser; A reflector, used for reflecting the laser emitted by the laser transmitter; A telescope, used to send the laser reflected by the reflector to the detection area; An optical path image acquisition unit, used to photograph the laser emission direction and acquire an image of the laser emission direction; An image recognition unit, used to identify and analyze the laser emission direction image; A motion control unit, used for adjusting the position of the reflector; The echo acquisition and analysis unit is used to collect and analyze the signals scattered back by aerosols and other components in the atmosphere after the laser emitted by the telescope irradiates the atmosphere of the detection area, and is connected to the micro control unit; The microcontroller unit is used to receive control instructions and issue execution instructions.

2. According to the image recognition-based laser radar optical path intelligent calibration system of claim 1, it is characterized in that: The image recognition unit recognizes and analyzes the laser emission direction image by comparing the real-time laser irradiation position image with the reference irradiation position image taken in advance to determine whether the optical path is seriously offset.

3. The laser radar optical path intelligent calibration system based on image recognition according to claim 2 is characterized in that: The laser irradiation position image is an image of the position of the light spot formed on the reflector by laser irradiation.

4. The laser radar optical path intelligent calibration system based on image recognition according to claim 3 is characterized in that: The optical path image acquisition unit is a high-definition camera, which can be used to capture the laser irradiation position image as the spot position formed by the laser irradiation on the reflector to form a clear image. The optical path image acquisition unit is connected to the image recognition unit.

5. The laser radar optical path intelligent calibration system based on image recognition according to claim 4 is characterized in that: The method for acquiring the reference image of the laser irradiation direction is to irradiate the laser onto a reflector at a forty-five degree angle to the laser direction through a laser transmitter, and the optical axis direction of the telescope is perpendicular to the laser irradiation direction, and then the image recognition unit is used to acquire the image of the spot position formed by the laser on the reflector at this time, which is the required reference image of the laser irradiation direction.

6. The laser radar optical path intelligent calibration system based on image recognition according to claim 5 is characterized in that: When obtaining the reference image of the laser irradiation direction, the irradiation direction of the laser after being reflected by a reflector with an inclination of forty-five degrees is vertically toward the sky, and the signal scattered back from a height of three kilometers is collected and analyzed by the echo signal collection and analysis unit. When the signal-to-noise ratio of the echo signal reaches the best, the spot position image formed by the laser irradiation on the reflector can be used as the reference image of the laser irradiation direction.

7. The laser radar optical path intelligent calibration system based on image recognition according to claim 1 is characterized in that: The motion control unit is composed of an optical motion component and a motion control unit circuit module, and the motion control unit is connected to a micro control unit.

8. The laser radar optical path intelligent calibration system based on image recognition according to claim 7 is characterized in that: The motion control unit is capable of adjusting the horizontal and vertical positions of the reflector.

9. The laser radar optical path intelligent calibration system based on image recognition according to claim 8, characterized in that: The image recognition unit is an image recognition comparison algorithm, and the image recognition unit is connected to the micro control unit.

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