Multi-distance laser radar illumination compensation calibration system and method

Abstract

The invention relates to a multi-distance laser radar illumination compensation calibration system and method, and the system comprises a radar installation platform which is used for fixing a to-be-measured laser radar and can rotate in the horizontal and pitching directions; a plurality of targets, wherein each target is provided with a light source with controllable light intensity and incident angle and a reflecting plate; the targets are deployed with the radar installation platform as the center, and the distances between the targets and the to-be-measured laser radar are different; the visual identification camera is used for acquiring the position of a radar laser spot; and the upper computer reads image data of the visual identification camera, controls the rotation of the radar installation platform in the horizontal and pitching directions and the light intensity and the incident angle of the light source on the target, and completes illumination compensation calibration and test of the laser radar under multiple distances. Compared with the prior art, the illumination intensity compensation table of the laser radar ranging values under different distances and different illumination environments can be accurately obtained, and the ranging precision under different illumination intensities can be effectively improved by adopting the illumination intensity compensation table for compensation.

Description

Technical Field

[0001] The present invention relates to the technical field of laser radar compensation calibration, and in particular to a multi-range laser radar illumination compensation calibration system and method. Background Art

[0002] With the rapid development of smart devices in recent years, LiDAR, as a simple and cost-effective sensor solution, has been applied from simple indoor environments to complex outdoor environments. The resulting scene changes have also put forward higher requirements for the relevant performance of LiDAR. Among them, the ability to resist light interference, as an unavoidable problem in outdoor scene applications, has become an important indicator for LiDAR to move towards outdoor applications.

[0003] Currently, laser radars increase their ability to resist light interference mostly by optimizing the hardware, which fundamentally improves the light resistance performance. However, this method is costly and it is not easy to further reduce the ranging error. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a system and method for compensating ranging values ​​for different distances and different ambient light illumination conditions during the production process of laser radar.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] As a first aspect of the present invention, a multi-range laser radar illumination compensation calibration system is provided, the system comprising:

[0007] The radar installation platform is used to fix the laser radar to be measured and can rotate in the horizontal and elevation directions;

[0008] A plurality of targets, each of which is provided with a light source and a reflector with controllable light intensity and incident angle; the plurality of targets are arranged with the radar installation platform as the center, each target is at a different distance from the laser radar to be measured, and the reflector plane of each target is perpendicular to the line connecting the center of the reflector and the horizontal rotation axis of the radar installation platform;

[0009] A visual recognition camera, which is mounted on the radar mounting platform and moves synchronously with the laser radar to be measured, and is used to obtain the position of the radar laser spot;

[0010] The host computer is connected to the radar installation platform, each target and the visual recognition camera signal respectively. It is used to read the image data of the visual recognition camera. Based on the position of the laser spot relative to the center of the target reflector, it controls the horizontal and pitch rotation of the radar installation platform and the light intensity and incident angle of the light source on the target to complete the illumination compensation calibration and testing of the laser radar at multiple distances.

[0011] As a preferred technical solution, the radar installation platform includes a radar fixing tool, a pitch rotation mechanism and a horizontal rotation mechanism;

[0012] The pitch rotation mechanism comprises a horizontally arranged pitch rotation motor, the output end of which is connected to the radar fixing tooling, and the pitch direction of the laser radar to be measured is adjusted by the pitch rotation motor;

[0013] The horizontal rotation mechanism includes a vertically arranged horizontal rotation motor, the output end of which is connected to the pitch rotation mechanism, and the horizontal orientation of the laser radar to be measured is adjusted by the horizontal rotation motor.

[0014] As a preferred technical solution, the radar fixing tool is provided with a quick-release mechanism for fixing and installing the laser radar to be measured.

[0015] As a preferred technical solution, the visual recognition camera is installed on the radar fixing tooling.

[0016] As a preferred technical solution, the light source with controllable light intensity and incident angle on the target includes a halogen lamp arranged on the target and an illumination pitch motor for controlling the rotation of the halogen lamp.

[0017] As a preferred technical solution, the target also includes a voltage regulating module for adjusting the brightness of the halogen lamp.

[0018] As a preferred technical solution, the target is also provided with a Bluetooth module, and is wirelessly connected to a host computer via the Bluetooth module.

[0019] As a second aspect of the present invention, a multi-range laser radar illumination compensation calibration method is provided, the method using the multi-range laser radar illumination compensation calibration system as described above, the steps comprising:

[0020] Perform system initialization and related self-tests;

[0021] Install the laser radar to be measured on the radar fixing fixture and perform spot calibration;

[0022] After completing the spot calibration of all position targets, the formal calibration procedure begins. The spot is controlled to fall on the target target according to the calibration position, and the ranging data and light intensity are collected. At the same time, the upper computer sends instructions for the change of luminous intensity and incident angle, the voltage regulating module starts to adjust the brightness of the halogen lamp, and the illumination pitch motor controls the halogen lamp to perform a cyclic up and down pitch movement. When the data collection of this position is completed, the data collection of the next position target is transferred to;

[0023] When all target data are collected, the collected data is processed and the calibration process ends.

[0024] As a preferred technical solution, the self-test includes brightness control of the halogen lamp, incident angle control of the halogen lamp light, and self-test of the horizontal and pitch directions of the radar mounting platform to ensure that the entire system is not restricted during movement.

[0025] As a preferred technical solution, the specific steps of the light spot calibration include:

[0026] Set the target to be measured, and the radar installation platform drives the laser radar to be measured toward the target through the horizontal rotation motor;

[0027] The host computer reads the image data of the visual recognition camera, obtains the position of the light spot relative to the center of the target reflector, and then adjusts the horizontal rotation motor and the pitch rotation motor so that the light spot falls on the center of the reflector;

[0028] After recording the position information, the spot calibration of the next target is carried out.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention proposes a laser radar illumination compensation calibration system under multiple distances, which utilizes the rotation of a halogen lamp to simulate different illumination incident angles, and controls the halogen lamp to change light and dark through a voltage regulator to simulate different illumination intensities. At the same time, the laser radar is placed on a rotating platform, and the targets at different distances are measured by the rotation of the rotating platform, and then the visual recognition system is used to ensure that the radar ranging spot is in the correct position of the target. In the above manner, the deviation between the laser radar ranging value and the actual distance value under different distances and different illumination environments can be accurately collected, and software can be used for fitting to generate an illumination intensity compensation table, and then the ranging value is compensated to obtain high-precision ranging data. It is possible to achieve a refined correction of the ranging value after reading the illumination intensity, which can effectively improve the ranging accuracy under different illumination intensities. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the structure of the multi-range laser radar illumination compensation calibration system of the present invention;

[0032] Figure 2 A top view of the structure of the multi-range laser radar illumination compensation calibration system of the present invention;

[0033] Figure 3 A stereoscopic diagram of the radar installation platform structure of the present invention;

[0034] Figure 4 It is a schematic diagram of the illumination compensation calibration system of the multi-range laser radar of the present invention;

[0035] Figure 5 This is a program flow chart of the multi-range laser radar illumination compensation calibration system of the present invention;

[0036] The numbers in the figure are as follows: 1. Workbench, 2. Radar installation platform, 3. Target, 4. Lighting pitch motor, 5. Halogen lamp, 6. Reflector, 7. Multi-target deployment position, 8. Quick release mechanism, 9. Visual recognition camera, 10. Radar fixing tooling, 11. Pitch rotation motor, 12. Horizontal rotation motor. DETAILED DESCRIPTION

[0037] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0038] Example 1

[0039] The present invention proposes a laser radar illumination compensation calibration system under multiple distances, which is used to test the illumination compensation of ranging values ​​and ranging accuracy under different distances and different ambient light conditions during the laser radar production process. It utilizes the rotation of a halogen lamp to simulate different light incident angles, and controls the halogen lamp to change light and dark through a voltage regulator to simulate different light intensities. At the same time, the laser radar is placed on a rotating platform, and the targets at different distances are measured by the rotation of the rotating platform, and then the visual recognition system is used to ensure that the radar ranging spot is in the correct position of the target. In the above manner, the deviation between the laser radar ranging value and the actual distance value under different distances and different lighting environments can be accurately collected, and the software can be used for fitting to generate a light intensity compensation table, and then the ranging value is compensated to obtain high-precision ranging data.

[0040] like Figure 1 As shown, the present invention includes a workbench 1, a radar installation platform 2, a plurality of targets 3 and a host computer, wherein the radar installation platform 2 is installed and fixed above the workbench 1, and the targets 3 are sequentially deployed around the workbench 1, and the number can be increased or decreased according to demand.

[0041] The radar installation platform 2 is installed above the workbench 1 to fix the laser radar to be measured; the periphery of the workbench 1 is as follows Figure 2 As shown, several targets 3 are deployed, and each group of targets 3 has a different distance from the laser radar to be measured, so as to obtain radar ranging data at different distances; a reflector 6 is installed on the target 3, and the halogen lamp 5 is controlled by the illumination pitch motor 4 to rotate in the pitch direction to simulate different illumination incident angles, and the brightness of the halogen lamp 5 is controlled to simulate different illumination intensities.

[0042] The specific deployment method of multiple targets 3 refers to Figure 2 As shown, the plane of the reflector plate 6 on each target 3 needs to be perpendicular to the line connecting the center of the plate and the horizontal rotation axis of the radar mounting platform, and the length of the line is used as the actual distance from the position target 3 to the laser radar to be measured.

[0043] Schematic diagram of radar installation platform 2 Figure 3 As shown, it includes a quick-release mechanism 8 and a radar fixing fixture 10 for fixing the laser radar to be measured. The visual recognition camera 9 is installed above the radar fixing fixture 10 to obtain the position of the laser spot. The horizontal rotation motor 12 can adjust the horizontal direction of the entire radar installation platform 2 so that it faces the targets 3 at different positions. It can also be combined with the visual acquisition information to adjust the position of the radar laser spot on the reflector 6 together with the pitch rotation motor 11. The radar installation platform 2 can rotate in the horizontal and pitch directions, and can cooperate with the visual recognition camera 9 to adjust the spot to the center of the reflector 6, and ensure that the spot is shot to targets at different distances according to the test requirements.

[0044] like Figure 4 As shown, the target 3 is installed with an illumination pitch motor 4, a halogen lamp 5, a reflector 6 and related controllers, a Bluetooth module, etc., wherein the illumination pitch motor 4 can drive the halogen lamp 5 to rotate, so that the light of the halogen lamp 5 can hit the reflector 6 at different incident angles.

[0045] Example 2

[0046] As another implementation of the present application, this embodiment also provides a calibration method for the multi-range laser radar illumination compensation calibration system using the above embodiment, such as Figure 5 As shown, the specific steps are as follows:

[0047] First, the system is initialized and related self-tests are performed, including the brightness control of the halogen lamp, the incident angle control of the halogen lamp light, the horizontal and pitch movement self-test of the radar installation platform, etc., to ensure that the entire system is not restricted during movement.

[0048] After the self-test is completed, the laser radar to be measured is installed on the radar fixing tooling 10, and the light spot calibration is performed: after setting the target 3 to be measured, the horizontal rotation motor 12 of the radar mounting platform 2 is rotated until the laser radar to be measured is facing the target target, and then the upper computer reads the image data of the visual recognition camera 9 to obtain the position of the light spot relative to the center of the target reflector, and then adjusts the horizontal and pitch motors so that the light spot falls on the center position of the reflector 3. After recording the position information, the light spot calibration of the next target 3 is performed.

[0049] After completing the calibration of the target spot at all positions, the formal calibration procedure is entered. The spot is controlled to fall on the target target according to the calibration position, and the ranging data and light intensity are collected. At the same time, the upper computer sends the instructions for the change of luminous intensity and incident angle, the voltage regulating module starts to adjust the brightness of the halogen lamp 5, and the illumination pitch motor 4 controls the halogen lamp 5 to perform a cyclic up and down pitch movement. When the data collection of this position is completed, the data collection of the target at the next position is transferred. When all the target data are collected, the collected data is processed, and the calibration or test process is ended.

[0050] Through the above method, the radar measurement data under different light intensities, different light incident angles and different distances can be obtained, and the light compensation and accuracy test of the lidar can be realized in combination with the actual distance information.

[0051] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A multi-range laser radar illumination compensation calibration system, characterized in that: The system comprises: A radar mounting platform (2), used to fix the laser radar to be measured, capable of rotating in horizontal and elevation directions; A plurality of targets (3), each of which is provided with a light source and a reflector (6) with controllable light intensity and incident angle; the plurality of targets (3) are deployed with the radar installation platform (2) as the center, each target (3) is at a different distance from the laser radar to be measured, and the reflector plane of each target (3) is perpendicular to a line connecting the center of the reflector (6) and the horizontal rotation axis of the radar installation platform (2); A visual recognition camera (9) is mounted on the radar mounting platform (2) and moves synchronously with the laser radar to be measured, and is used to obtain the position of the radar laser spot; The host computer is respectively connected to the radar installation platform (2), each target (3) and the visual recognition camera (9) by signal, and is used to read the image data of the visual recognition camera (9), and based on the position of the laser spot relative to the center of the target reflection plate, control the rotation of the radar installation platform (2) in the horizontal and pitch directions and the light intensity and incident angle of the light source on the target (3), so as to complete the illumination compensation calibration and test of the laser radar at multiple distances.

2. A multi-range laser radar illumination compensation calibration system according to claim 1, characterized in that: The radar installation platform (2) comprises a radar fixing tool (10), a pitch rotation mechanism and a horizontal rotation mechanism; The pitch rotation mechanism comprises a pitch rotation motor (11) arranged horizontally, the output end of the pitch rotation motor (11) is connected to a radar fixing tool (10), and the pitch direction of the laser radar to be measured is adjusted by the pitch rotation motor (11); The horizontal rotation mechanism comprises a vertically arranged horizontal rotation motor (12), the output end of the horizontal rotation motor (12) is connected to the pitch rotation mechanism, and the horizontal orientation of the laser radar to be measured is adjusted by the horizontal rotation motor (12).

3. A multi-range laser radar illumination compensation calibration system according to claim 2, characterized in that: The radar fixing tool (10) is provided with a quick-release mechanism (8) for fixing and installing the laser radar to be measured.

4. The multi-range laser radar illumination compensation calibration system according to claim 2, characterized in that: The visual recognition camera (9) is installed on the radar fixing tool (10).

5. The multi-range laser radar illumination compensation calibration system according to claim 1, characterized in that: The light source with controllable light intensity and incident angle on the target (3) comprises a halogen lamp (5) arranged on the target (3) and an illumination pitch motor (4) for controlling the rotation of the halogen lamp (5).

6. The multi-range laser radar illumination compensation calibration system according to claim 5, characterized in that: The target (3) also includes a voltage regulating module for adjusting the brightness of the halogen lamp (5), and a controller for controlling the illumination pitch motor (4).

7. The multi-range laser radar illumination compensation calibration system according to claim 6, characterized in that: The target (3) is also provided with a Bluetooth module, and the Bluetooth module is respectively connected to the voltage regulating module and the controller via serial port communication, and is wirelessly connected to the host computer.

8. A multi-range laser radar illumination compensation calibration method, characterized in that: The method utilizes the multi-range laser radar illumination compensation calibration system as described in any of claims 1 to 7, and the steps include: Perform system initialization and self-test; The laser radar to be measured is installed on a radar fixing fixture (10) to calibrate the light spot of each target (3); After the spot calibration of all position targets (3) is completed, the illumination compensation calibration program is entered, and the spot is controlled to fall on the target target in sequence according to the spot calibration position; the upper computer sends instructions for changes in luminous intensity and incident angle, and the voltage regulating module starts to adjust the brightness of the halogen lamp (5), and the illumination pitch motor (4) controls the halogen lamp (5) to perform cyclic up and down pitch movements, while collecting the laser radar ranging data and illumination intensity to be measured; After all target data are collected, the deviation between the LiDAR ranging value and the actual distance value under different distances and lighting environments is obtained, and a light intensity compensation table is fitted to complete the LiDAR light compensation calibration under multiple distances.

9. A multi-range laser radar illumination compensation calibration method according to claim 8, characterized in that: The self-test includes the brightness control of the halogen lamp, the incident angle control of the halogen lamp light, and the horizontal and pitch direction movement self-test of the radar installation platform to ensure that the entire system is not restricted during movement.

10. The multi-range laser radar illumination compensation calibration method according to claim 8, characterized in that: The specific steps of the light spot calibration include: A target (3) to be measured is set, and the radar installation platform (2) is rotated by a horizontal rotary motor (12) to drive the laser radar to be measured toward the target; The host computer reads the image data of the visual recognition camera (9), obtains the position of the light spot relative to the center of the target reflector, and then adjusts the horizontal rotation motor (12) and the pitch rotation motor (11) so that the light spot falls on the center of the reflector; after recording the position information, the light spot calibration of the next target (3) is carried out.

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