A laser radar optical axis consistency correction system and method

Abstract

The application relates to a laser radar optical axis consistency correction system and method, which comprises a laser radar product to be corrected, a simulated target point adjusting device, a conversion plate, a laser light spot recording device and a sighting telescope. The simulated target point adjusting device is used for determining the position of a simulated target point according to the distance of a detected target point of the laser radar product to be corrected. The conversion plate is located at the position of the simulated target point and is used for photoelectrically converting the emitted laser of the laser radar product to be corrected to obtain a coarsely adjusted light spot position. The laser light spot recording device is used for finely adjusting the coarsely adjusted light spot position to obtain accurate light spot position information. The sighting telescope is distributed at intervals from the laser radar product to be corrected and is used for determining the result of the optical axis consistency correction of the laser receiving end of the laser radar product to be corrected based on the optical axis position consistency relationship among the sighting telescope, the simulated target point adjusting device and the conversion plate. The laser radar optical axis consistency correction system provided by the application is simple to operate, high in correction efficiency and applicable to batch production.

Description

Technical Field

[0001] This invention relates to the field of lidar technology, and in particular to a lidar optical axis consistency correction system and method. Background Technology

[0002] LiDAR is an active range detection device that uses a laser as the emission light source and employs photoelectric detection technology. It has the advantages of small size and high measurement accuracy, and is widely used in fields such as autonomous driving, automated guided vehicles, and robots.

[0003] Currently used lidar uses a non-coaxial design for its transmitting and receiving beams. This design does not pose a threat to the photoelectric receiver. To ensure that the transmitting and receiving beams remain coaxial or parallel, the transmitting and receiving components need to be calibrated. The traditional calibration method involves calibrating outdoors using a physical target, emitting a laser beam from the transmitting component, observing and measuring the target at a limited distance, adjusting the laser emission plate to meet the required spot size, and then measuring the electrical signal at the lidar receiver using an oscilloscope. The probe is moved back and forth to find the point of maximum pulse, thus completing the calibration of the lidar transmitting and receiving components. This method is time-consuming, labor-intensive, inefficient, and unsuitable for mass production. Summary of the Invention

[0004] In view of this, it is necessary to provide a lidar optical axis consistency correction system and method to solve the problem that the correction efficiency of lidar transmitting and receiving components is low and cannot be adapted to mass production in the prior art.

[0005] This invention provides a lidar optical axis consistency correction system, comprising: a lidar product to be corrected, a simulated target point adjustment device, a conversion plate, a laser spot recording device, and a sight;

[0006] The simulated target point adjustment device is spaced apart from the lidar product to be calibrated, and is used to receive the laser emitted by the lidar product to be calibrated, and determine the position of the simulated target point according to the detection target point distance of the lidar product to be calibrated.

[0007] The conversion board is located at the simulated target point and is used to receive the laser emitted by the lidar product to be calibrated and to perform photoelectric conversion on the laser emitted by the lidar product to be calibrated to obtain the position of the coarse adjustment spot.

[0008] The laser spot recording device is spaced apart from the conversion plate to acquire the coarse adjustment spot position on the conversion plate and to fine adjust the coarse adjustment spot position to obtain accurate spot position information.

[0009] The sight and the lidar product to be calibrated are spaced apart, and are used to determine the result of optical axis consistency calibration of the laser receiver of the lidar product to be calibrated based on the optical axis position consistency relationship of the sight, the simulated target point adjustment device and the conversion plate.

[0010] Furthermore, the simulated target point adjustment device includes a collimator and an electronic front mirror. The collimator is distributed along the laser light path direction emitted by the lidar product to be calibrated, and the collimator is spaced apart from the lidar product to be calibrated. The electronic front mirror is spaced apart from the collimator.

[0011] Furthermore, the collimator is an off-axis reflective collimator.

[0012] Furthermore, the collimator is distributed parallel to the laser emission direction of the lidar product to be calibrated.

[0013] Furthermore, the laser spot recording device includes an emission light recording unit; the emission light recording unit includes a first infrared acquisition device and a first analysis device, the first infrared acquisition device is used to acquire the coarse adjustment spot position on the conversion board; the first analysis device is communicatively connected to the first acquisition device, and the first analysis device is used to analyze and process the coarse adjustment spot position to obtain precise spot position information, and save the precise spot position information.

[0014] Furthermore, the sight is a visible light sight.

[0015] Furthermore, it also includes an adjustment bracket, which is fixedly installed on the calibration system test platform. The adjustment bracket has multiple degrees of freedom, and the lidar product to be calibrated and the sight are fixedly installed on the adjustment bracket.

[0016] Furthermore, the adjustment bracket includes a first adjustment part and a second adjustment part, the first adjustment part and the second adjustment part having relatively independent rotational degrees of freedom, the lidar product to be calibrated is fixedly installed on the first adjustment part, and the sight is fixedly installed on the second adjustment part.

[0017] Furthermore, it also includes a rhomboid prism, which is spaced apart from the electronic front sight and is located between the aiming scope and the electronic front sight.

[0018] Secondly, the present invention also provides a method for laser radar optical axis consistency correction, applied to a laser radar optical axis consistency correction system as described in any of the above claims, the method comprising:

[0019] Obtain the target calibration distance of the lidar product to be calibrated;

[0020] Based on the target correction distance, adjust the focus position of the simulated target point adjustment device to determine the simulated target point position;

[0021] Based on the laser spot recording device, the precise spot position information when the laser spot energy on the conversion plate is at its maximum is obtained and marked as the first spot position information;

[0022] The lasers from each laser source in the lidar product to be calibrated are emitted cyclically, and the precise spot position is acquired in real time through the laser spot recording device and marked as the second spot position information.

[0023] Based on the overlap between the first spot position information and the second spot position information, the correction result of the transmitter of the lidar product to be corrected is determined;

[0024] Based on the aiming scope, the precise spot position information when the laser spot energy on the conversion board is at its maximum is obtained, and the correction result of the receiving end of the lidar product to be corrected is determined.

[0025] The lidar optical axis consistency correction system and method employed in this invention, compared with existing technologies, utilizes a simulated target point adjustment device. This device's focal point is adjusted based on the distance to the target point detected by the lidar product, thus determining the position of a simulated target point close to the lidar product. This simulated target point position replaces the infinitely distant target point position used during lidar product correction, freeing the lidar correction from the limitations of site size. Furthermore, the simulated target point positioning is fast and accurate, improving the efficiency of lidar correction. Simultaneously, a conversion plate performs photoelectric conversion, transforming the laser emitted by the lidar product into a visible light spot. Finally, a laser spot recording device records, analyzes, and monitors the data in real time, guiding adjustments to the lidar product's emitting plate to maximize spot energy for correction. The system also records the spot position at maximum energy, further improving the efficiency and reliability of lidar correction. Moreover, the system is suitable for mass production and application.

[0026] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0027] Figure 1 A schematic diagram of an embodiment of the lidar optical axis consistency correction system provided by the present invention;

[0028] Figure 2 This is a schematic diagram of an embodiment of the lidar optical axis consistency correction method provided by the present invention. Detailed Implementation

[0029] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0030] The lidar optical axis consistency correction system provided in this embodiment of the invention is described in detail below. Figure 1 It includes: 1. LiDAR product to be calibrated, 2. Simulated target point adjustment device, 3. Conversion plate, 4. Laser spot recording device, and 5. Sight scope;

[0031] The simulated target point adjustment device 2 is spaced apart from the lidar product 1 to be calibrated, and is used to receive the laser emitted by the lidar product 1 to be calibrated, and determine the position of the simulated target point according to the detection target point distance of the lidar product 1 to be calibrated.

[0032] The conversion board 3 is located at the simulated target point and is used to receive the laser emitted by the lidar product 1 to be calibrated, and to perform photoelectric conversion on the laser emitted by the lidar product 1 to obtain the position of the coarse adjustment spot.

[0033] The laser spot recording device 4 is spaced apart from the conversion plate 3, and is used to acquire the coarse adjustment spot position on the conversion plate 3, and to fine adjust the coarse adjustment spot position to obtain accurate spot position information.

[0034] The aiming scope 5 and the lidar product 1 to be calibrated are spaced apart, and are used to determine the result of the optical axis consistency correction of the laser receiver of the lidar product 1 to be calibrated based on the optical axis position consistency relationship of the aiming scope 5, the simulated target point adjustment device 2 and the conversion plate 3.

[0035] In this embodiment, by setting up a simulated target point adjustment device 2, the focal position of the simulated target point adjustment device 2 is adjusted according to the distance of the detection target point of the lidar product, thereby determining the position of the simulated target point close to the lidar product. This simulated target point position replaces the infinitely distant target point position during lidar product calibration, thus freeing lidar calibration from the limitations of site size. Simultaneously, the simulated target point positioning is fast and accurate, improving the efficiency of lidar calibration. Furthermore, a conversion board 3 performs photoelectric conversion, converting the laser emitted by the lidar product into a visible light spot. Finally, a laser spot recording device 4 records, analyzes, and guides the adjustment of the lidar product's emitting board to maximize the light spot energy, thereby calibrating the lidar product. The system also records the position of the light spot when the energy is at its maximum, further improving the efficiency and reliability of lidar calibration. Moreover, the system can be used for mass production and application.

[0036] It should be noted that the lidar product 1 to be calibrated can be any product on the market that requires laser calibration. The laser model and quantity of its transmitter board, as well as the laser model and data of its receiver board, are not restricted. If there are multiple lasers on the transmitter board, the laser axes are calibrated in sequence until all lasers meet the calibration requirements.

[0037] Furthermore, while performing photoelectric conversion, the conversion plate 3 can also coarsely adjust the position of the light spot, so that the approximate position of the light spot is visible, which facilitates the positioning and acquisition by the laser light plate recording device.

[0038] In some embodiments, the simulated target point adjustment device 2 includes a collimator 21 and an electronic front mirror 22. The collimator 21 is distributed along the laser light path direction emitted by the lidar product 1 to be calibrated. The collimator 21 and the lidar product 1 to be calibrated are distributed at intervals. The electronic front mirror 22 and the collimator 21 are distributed at intervals.

[0039] In this embodiment, based on the distance that needs to be detected during the calibration of the lidar product 1, the focal position of the collimator 21 and the electronic front mirror 22 is calculated. The positions of the collimator 21 and the electronic front mirror 22 are adjusted according to the focal position, so that the focal position is used as the simulated target point position to replace the target point at a finite distance, thus solving the problem of calibration being limited by the environmental position.

[0040] Furthermore, by using the simulated target point adjustment device 2, the position of the target object at a limited distance is transferred to the vicinity of the lidar product 1 to be calibrated, thus removing the site restrictions during lidar product calibration. Moreover, the position of the simulated target point can be arbitrarily set according to actual needs, either close to the lens of the lidar product or distributed at intervals.

[0041] In one specific embodiment, the simulated target point adjustment device 2 needs to simulate the focal point movement of a 200m target by 5mm and 0.1mm respectively. The focal point of the collimator 21 is shifted 5mm towards the reflecting mirror, and the reticle in the electronic front mirror 22 is shifted 0.1mm towards the objective lens to complete the simulation of a finite distance target.

[0042] The collimator 21 can be a cassette type, an off-axis reflective type, or a transmissive type. In order to achieve better focusing effect, and to bring the simulated target point closer to the lidar product location, and to facilitate installation, in this embodiment, the collimator 21 is an off-axis reflective type collimator 21.

[0043] The optical path receiving direction of the collimator 21 can be parallel to the laser emission direction of the lidar, or it can be obliquely distributed to the laser emission direction of the lidar. In order to reduce the difficulty of focal point calculation caused by the oblique distribution of the collimator 21 to the laser emission direction of the lidar, which would result in a certain angle between the light rays, the collimator 21 and the laser emission direction of the lidar product 1 to be calibrated, in this embodiment, the collimator 21 is distributed parallel to the laser emission direction of the lidar product 1 to be calibrated.

[0044] In some embodiments, the electronic front-facing lens 22 is a 120mm electronic front-facing lens 22. It is understood that in different embodiments, the electronic front-facing lens 22 may have different lens parameters.

[0045] In some embodiments, the laser spot recording device 4 includes an emission light recording unit 41;

[0046] The emitted light recording unit includes a first infrared acquisition device 411 and a first analysis device 412. The first infrared acquisition device is used to acquire the position of the coarse adjustment spot on the conversion plate 3. The first analysis device is communicatively connected to the first acquisition device. The first analysis device is used to analyze and process the position of the coarse adjustment spot to obtain precise spot position information and save the precise spot position information.

[0047] In this embodiment, the emitted light recording unit can analyze when the light spot energy is at its maximum, thereby accurately locating the position of the light spot when the light spot energy is at its maximum.

[0048] In one specific embodiment, the first infrared acquisition device is an infrared camera, and the first analysis device is a laptop computer.

[0049] In some embodiments, the aiming scope 5 is a visible light aiming scope 5.

[0050] In this embodiment, by setting the aiming scope 5 as a visible light aiming scope 5, observation becomes visible to the naked eye, improving detection efficiency. In this embodiment, the aiming scope 5 is a white light aiming scope 5.

[0051] In some embodiments, an adjustment bracket 6 is also included, which is fixedly installed on the calibration system test platform. The adjustment bracket 6 has multiple degrees of freedom, and the lidar product 1 to be calibrated and the aiming scope 5 are fixedly installed on the adjustment bracket.

[0052] In this embodiment, by setting an adjustment bracket 6 and fixing the lidar product 1 to be calibrated and the aiming scope 5 on the adjustment bracket 6, the pitch and swing of the lidar product 1 to be calibrated and the aiming scope 5 can be adjusted by the adjustment bracket 6.

[0053] In some embodiments, the adjustment bracket 6 includes a first adjustment part and a second adjustment part, the first adjustment part and the second adjustment part having relatively independent rotational degrees of freedom, the lidar product to be calibrated being fixedly installed on the first adjustment part, and the sight being fixedly installed on the second adjustment part.

[0054] In this embodiment, the adjustment bracket 6 is configured as a first adjustment part and a second adjustment part, and both the first adjustment part and the second adjustment part have relatively independent rotational degrees of freedom, which can adjust the installation angle of the lidar product 1 to be calibrated and the aiming scope 5 respectively, so as to realize the optical axis calibration of the lidar product 1 to be calibrated.

[0055] In some embodiments, the system further includes an oblique prism 9, which is spaced apart from the electronic front sight 22 and is located between the aiming scope 5 and the electronic front sight 22.

[0056] In this embodiment, by setting an orthorhombic prism, the accuracy of the received light correction can be improved.

[0057] Based on the aforementioned lidar optical axis consistency correction system, this invention also provides a lidar optical axis consistency correction method. Please refer to [link to relevant documentation]. Figure 2 The methods include:

[0058] S201. Obtain the target calibration distance of the lidar product to be calibrated;

[0059] S202. Adjust the focus position of the simulated target point adjustment device according to the target correction distance to determine the simulated target point position;

[0060] S203. Based on the laser spot recording device, obtain the precise spot position information when the laser spot energy on the conversion plate is at its maximum, and mark it as the first spot position information;

[0061] S204. Continuously emit lasers from each laser source in the lidar product to be calibrated, and obtain the precise spot position in real time through the laser spot recording device, and mark it as the second spot position information;

[0062] S205. Based on the overlap between the first spot position information and the second spot position information, determine the correction result of the transmitter of the lidar product to be corrected;

[0063] S206. Based on the aiming scope, obtain the precise spot position information when the laser spot energy on the conversion board is at its maximum, and determine the correction result of the receiving end of the lidar product to be corrected.

[0064] In one specific embodiment, the lidar product to be calibrated includes a transmitter board 1 and a transmitter board 2. The transmitter board 1 includes laser LDs numbered 1 to 16, and the transmitter board 2 includes laser LDs numbered 17 to 32.

[0065] In this embodiment, the laser emitted by the LD numbered 8 in the emitting board 1 is controlled by the software of the lidar product to be calibrated, so that the laser passes through the emitting cylindrical mirror optical system and is in working state; the emitted laser is focused by the off-axis reflective collimator 21 to the focal position of the simulated 200m target. Since the laser is 905nm, a conversion board is placed at the focal position of the simulated 200m target so that the laser conversion board displays the laser spot, which is convenient for initial debugging.

[0066] Furthermore, a laser spot recording device, constructed using an infrared lens, tooling line 1, an infrared camera, and a laptop computer, observes the laser emitted by LD No. 8, which is focused by an off-axis reflective collimator 21 onto a spot at a simulated 200m target focal position. By adjusting the position of the laser emitting plate 1 of the lidar product to be calibrated, the observed laser spot energy is maximized, and the spot position is recorded.

[0067] Furthermore, the lasers emitted by the LDs numbered 12 and 24 in the emitter board 1 and emitter board 2 are controlled by the software of the lidar product to be calibrated. The laser convergence spot of the LDs numbered 12 and 24 is observed with a laptop computer. The position of the laser emitter board of the lidar product to be calibrated is adjusted to maximize the energy of the convergence laser spot emitted by the LDs 12 and 24, and the spot position is recorded.

[0068] Furthermore, by switching the software of the lidar product to be calibrated between the emitters 8, 12 and 24 in emitter board 1 and emitter board 2, the laser beams are displayed on the laptop screen. The energy of the converged laser beams emitted by LDs 8, 12 and 24 is observed to be the maximum, and whether the position is the same as the previous record. If they are different, the position of the laser emitter board of the lidar product to be calibrated is adjusted so that the energy of the converged laser beams of the three beams is the maximum, and the position is the same as the previous record. Based on the principle that three points form a plane, the position of the 32 LDs is determined.

[0069] Furthermore, by switching the software between the lidar products to be calibrated, the LDs numbered 14 and 26 in the transmitter board 1 and transmitter board 2 are controlled to emit lasers, so that the laser spots are displayed on the laptop. The convergence spot energy of the LDs numbered 14 and 26 is verified to be the maximum, that is, the laser emission system of the lidar product to be calibrated is calibrated.

[0070] Furthermore, by adjusting the position of the white light sight, it is aimed at the laser spot on the off-axis reflective collimator 21 and the conversion plate, so that the laser spot can be seen, i.e., the white light sight and the laser emission system of the product under test are coaxial; the laser radar product to be calibrated and the white light sight are placed in front of the optical platform built by the rhomboid prism, the 120mm electronic front mirror, the tooling line 2, and the display, and the white light sight is aligned with the simulated target reticle at 200m in the 120mm electronic front mirror, so that the optical axes of the 120mm electronic front mirror and the white light sight are coaxial; by adjusting the position of the receiver board, i.e., the 32 APDs, in the laser radar product to be calibrated, the display can see the laser spot. Observe the receiving board carefully; since an LD is installed at position 24 of the APD on the receiving board, the LD can be controlled by the software of the lidar product to be calibrated to emit light, which is then focused on position 24 of the LD on the transmitting board 2 after passing through the transmitting and receiving systems. This means that the laser receiving calibration of the lidar product to be calibrated is complete. The white light sight and the laser transmitting system of the lidar product to be calibrated are coaxial, the optical axis of the white light sight and the 120mm electronic front sight are coaxial, and the 120mm electronic front sight and the 32 APD laser receiving systems in the lidar product to be calibrated are coaxial. This means that the transmitting axis and the receiving axis of the lidar product to be calibrated are coaxial, and the lidar optical axis consistency calibration is complete.

[0071] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A lidar optical axis consistency correction system, characterized in that, include: The lidar product to be calibrated, the simulated target point adjustment device, the conversion board, the laser spot recording device, and the aiming scope; The simulated target point adjustment device is spaced apart from the lidar product to be calibrated, and is used to receive the laser emitted by the lidar product to be calibrated, and determine the position of the simulated target point according to the detection target point distance of the lidar product to be calibrated. The conversion board is located at the simulated target point and is used to receive the laser emitted by the lidar product to be calibrated and to perform photoelectric conversion on the laser emitted by the lidar product to be calibrated to obtain the position of the coarse adjustment spot. The laser spot recording device is spaced apart from the conversion plate to acquire the coarse adjustment spot position on the conversion plate and to fine adjust the coarse adjustment spot position to obtain accurate spot position information. The laser spot recording device includes an emitted light recording unit; The emitted light recording unit includes a first infrared acquisition device and a first analysis device. The first infrared acquisition device is used to acquire the position of the coarse adjustment spot on the conversion board. The first analysis device is communicatively connected to the first infrared acquisition device. The first analysis device is used to analyze and process the position of the coarse adjustment spot to obtain precise spot position information and save the precise spot position information. The sight and the lidar product to be calibrated are spaced apart, which is used to determine the result of optical axis consistency calibration of the laser receiver of the lidar product to be calibrated based on the optical axis position consistency relationship of the sight, the simulated target point adjustment device and the conversion plate. The simulated target point adjustment device includes a collimator and an electronic front mirror. The collimator is distributed along the laser light path direction emitted by the lidar product to be calibrated. The collimator is spaced apart from the lidar product to be calibrated. The electronic front mirror is spaced apart from the collimator. It also includes a rhombus prism, which is spaced apart from the electronic front sight and is located between the aiming scope and the electronic front sight.

2. The lidar optical axis consistency correction system according to claim 1, characterized in that, The collimator is an off-axis reflective collimator.

3. The lidar optical axis consistency correction system according to claim 2, characterized in that, The collimator is distributed parallel to the laser emission direction of the lidar product to be calibrated.

4. The lidar optical axis consistency correction system according to claim 1, characterized in that, The sight is a visible light sight.

5. The lidar optical axis consistency correction system according to claim 1, characterized in that, It also includes an adjustment bracket, which is fixedly installed on the calibration system test platform. The adjustment bracket has multiple degrees of freedom, and the lidar product to be calibrated and the aiming scope are fixedly installed on the adjustment bracket.

6. The lidar optical axis consistency correction system according to claim 5, characterized in that, The adjustment bracket includes a first adjustment part and a second adjustment part, the first adjustment part and the second adjustment part having relatively independent rotational degrees of freedom. The lidar product to be calibrated is fixedly installed on the first adjustment part, and the sight is fixedly installed on the second adjustment part.

7. A method for calibrating the optical axis consistency of a lidar, applied to the lidar optical axis consistency calibration system as described in any one of claims 1-6, characterized in that, The method includes: Obtain the target calibration distance of the lidar product to be calibrated; Based on the target correction distance, adjust the focus position of the simulated target point adjustment device to determine the simulated target point position; Based on the laser spot recording device, the precise spot position information when the laser spot energy on the conversion plate is at its maximum is obtained and marked as the first spot position information; The lasers from each laser source in the lidar product to be calibrated are emitted cyclically, and the precise spot position is acquired in real time through the laser spot recording device and marked as the second spot position information. Based on the overlap between the first spot position information and the second spot position information, the correction result of the transmitter of the lidar product to be corrected is determined; Based on the aiming scope, the precise spot position information when the laser spot energy on the conversion board is at its maximum is obtained, and the correction result of the receiving end of the lidar product to be corrected is determined.

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