A calibration device and method for LiDAR used in architectural design

Abstract

This invention relates to the field of laser detection technology, specifically to a laser radar calibration device and method for architectural design. The laser radar calibration device includes a cylindrical base with a laser radar positioned in the center. N calibration plates are evenly distributed along the circumference of the base's outer perimeter. The calibration plates are rotatably mounted on the base and have corresponding first and second operating states before and after rotation. In the first operating state, the distances between the N calibration plates and the laser radar are equal or continuously changing. In the second operating state, the laser beam emitted by the laser radar is reflected back to the laser radar after passing through at least two calibration plates. The laser radar calibration method includes calibrating the laser radar using either the first or second operating mode depending on the situation, enabling the laser radar to obtain multiple sets of measurement data in a single measurement, thus shortening the calibration time and improving the calibration efficiency.

Description

Technical Field

[0001] This invention relates to the field of laser detection technology, and in particular to a laser radar calibration device and calibration method for architectural design. Background Technology

[0002] A lidar is a radar system that uses laser beams to detect the position, velocity, and other characteristics of a target. Its working principle is to first emit a detection laser beam towards the target, then compare the received signal reflected back from the target with the emitted signal, and after appropriate processing, obtain relevant information about the target.

[0003] Traditional lidar calibration methods typically take place in an enclosed room with minimal electromagnetic interference and obstructions. In practice, the same test board is placed at different locations from the lidar to be calibrated. The lidar then detects the board and collects data. This data is subsequently analyzed and processed, and the parameters of the laser emitter are adjusted accordingly to complete the lidar calibration. However, in practice, moving the test board between different distances often relies on manual handling or AGV transport. This method has significant drawbacks: manual operation is prone to inaccurate placement due to operational errors and fatigue; AGVs may also encounter path planning errors and operational instability, preventing the test board from reaching the ideal calibration position, ultimately resulting in a significant reduction in calibration accuracy. Furthermore, the frequent movement and repositioning of the test board between different distances greatly increases the time cost of the entire calibration process, leading to low calibration efficiency.

[0004] To improve the accuracy and efficiency of lidar calibration, Chinese patent CN109001713B discloses a ranging accuracy calibration system. This system keeps the lidar and reflector in a fixed vertical position during the lidar calibration process, thus eliminating the need to repeatedly move the reflector in the direction of the lidar's light path. Furthermore, it achieves rapid calibration of lidar ranging by changing the receiving area of ​​the reflector.

[0005] However, the above-mentioned ranging accuracy calibration system also has some problems in actual use: it can only acquire one set of data at a time, and lacks other data for comparison and verification, making it difficult to guarantee the reliability of the data. It can easily cover up measurement errors caused by individual differences in equipment, accidental environmental factors, etc., thus affecting the calibration efficiency and final calibration accuracy of the lidar. Summary of the Invention

[0006] Therefore, it is necessary to provide a calibration device and method for LiDAR used in architectural design to address the problems of low efficiency and poor accuracy in the current calibration process of LiDAR.

[0007] The above objectives are achieved through the following technical solutions:

[0008] A lidar calibration device for architectural design, the lidar calibration device for architectural design comprising:

[0009] The laser radar is coaxially mounted on the top of the cylindrical base and can rotate around its own axis during use.

[0010] The calibration plate comprises N calibration plates, which are evenly distributed along the circumferential direction on the outer peripheral wall of the base. Each calibration plate is set at the same height as the lidar and can slide along the radial direction of the base. The calibration plate is used to reflect the laser beam emitted by the lidar back to the lidar so that the lidar can measure the laser beam and obtain measurement parameters.

[0011] The calibration plate is rotatably mounted on the base along a first axis and has a first working state and a second working state before and after rotation. The first axis is parallel to the axis of the base. Before rotation, the reflective surface of the calibration plate is perpendicular to the laser beam emitted by the lidar. The calibration plate is in the first working state, and the calibration distance between N calibration plates and the lidar is equal or the distance between N calibration plates and the lidar continuously changes to the calibration distance. After rotation, the calibration plate is in the second working state, and the laser beam emitted by the lidar returns to the lidar after being reflected by at least two calibration plates.

[0012] Furthermore, the measurement parameters include at least the time of flight of the laser beam.

[0013] Furthermore, the laser radar calibration device for architectural design also includes a driving element for providing a driving force for the calibration plate to slide along the radial direction of the base.

[0014] This invention also provides a method for calibrating a lidar for architectural design, employing a lidar calibration device for architectural design, wherein the radius of the base is r; the distance between the calibration plate and the outer peripheral wall of the base is S, and the minimum value of S is... The maximum value of S is The minimum distance between the calibration board and the lidar is The maximum distance is The calibration distance between the calibration board and the lidar is... The laser radar calibration method for architectural design includes the following steps:

[0015] Step S100: Determine whether the first relation is true. The first relation is: ;

[0016] Step S200: When the first relation is true, determine whether the second relation is true. The second relation is... ;

[0017] Step S300: If successful, calibrate the lidar according to the first working mode;

[0018] If step S400 is not successful, the lidar is calibrated according to the second working mode.

[0019] Furthermore, in the first operating mode, the distance between each calibration board and the lidar is the calibration distance. When this happens, follow these steps:

[0020] In step S310, the lidar rotates while emitting a laser beam;

[0021] Step S320: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar.

[0022] Step S330: After the lidar rotates a preset number of times, the lidar is calibrated.

[0023] Furthermore, in the first operating mode, the distance between the N calibration boards and the lidar continuously changes to the calibration distance. At that time, the distance that the calibration plate slides in one radial direction along the base is set to be Initially, the distance between the first calibration board and the lidar is... Along the same circumferential direction of the base, the distance between the i-th calibration plate and the lidar is i = 1, 2 to N; and follow these steps:

[0024] In step S340, the lidar rotates while emitting a laser beam, and after the lidar scans the i-th calibration plate again, the i-th calibration plate slides a distance away from the axis of the base along the radial direction of the base. , i=1, 2 to N;

[0025] Step S350: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar.

[0026] Step S360, when At that time, the lidar is calibrated.

[0027] Furthermore, in the second operating mode, the distance between each calibration board and the lidar is the calibration distance. At that time, the distance between the first calibration board and the lidar is set to... The distance between the q-th calibration plate and the lidar is The distance between the first calibration plate and the qth calibration plate is The central angle formed by the first calibration plate and the qth calibration plate is the largest, and this central angle is... , Initially, the distance between all the calibration boards and the lidar is... ,but , And follow these steps:

[0028] Step S410, when hour,

[0029] Calculate the included angle ;

[0030] Step S420, calculate the included angle ;

[0031] Step S430, when At that time, the distance the q-th calibration plate slides along the radial direction of the base. ,at this time At this time, the distance between the q-th calibration plate and the lidar is , , This is the distance between the first calibration plate and the qth calibration plate at this time, and Calculate the included angles A and B;

[0032] Step S431: Adjust the angle between the reflective surfaces of all the calibration plates and the laser beam emitted by the lidar according to angles A and B;

[0033] In step S440, the lidar rotates while emitting a laser beam;

[0034] Step S441: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar.

[0035] Step S442: After the lidar rotates a preset number of times, the lidar is calibrated.

[0036] Furthermore, the radius of the lidar is After step S410, the method further includes:

[0037] Step S411: Calculate the perpendicular distance from the laser radar to the line connecting the first calibration plate and the qth calibration plate. ;

[0038] Step S412, when When calculating the included angle ;

[0039] Step S413, when At that time, the central angle formed by the first calibration plate and the (q-1)th calibration plate is , The distance between the first calibration plate and the lidar The distance between the (q-1)th calibration plate and the lidar The distance between the first calibration plate and the (q-1)th calibration plate Proceed through steps S410 to S442.

[0040] Furthermore, in the second operating mode, the distance between the N calibration boards and the lidar continuously changes to the calibration distance. At that time, the distance that the calibration plate slides in one radial direction along the base is set to be Initially, the distance between all the calibration boards and the lidar is... The distance between the first calibration board and the lidar is The distance between the q-th calibration plate and the lidar is The distance between the first calibration plate and the qth calibration plate is The central angle formed by the first calibration plate and the qth calibration plate is the largest, and this central angle is... , Initially, the distance between all the calibration boards and the lidar is... ,but , And follow these steps:

[0041] Step S450, when hour,

[0042] Calculate the included angle ;

[0043] Step S460, calculate the included angle ;

[0044] Step S470, when At that time, the distance the first calibration plate slides along the radial direction of the base. ,at this time , , This is the distance between the first calibration plate and the qth calibration plate at this time, and Calculate the included angles A and B;

[0045] Step S471: Adjust the angle between the reflective surfaces of all the calibration plates and the laser beam emitted by the lidar according to angles A and B;

[0046] In step S480, the lidar rotates while emitting a laser beam; and after the lidar scans the i-th calibration plate again, the i-th calibration plate slides a distance away from the axis of the base along the radial direction of the base. , i=1, 2 to N;

[0047] Step S481: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar.

[0048] Step S482, when At that time, the lidar is calibrated.

[0049] Furthermore, the calibration method for the lidar includes calculating the difference between the flight time of the laser beam after being reflected by each calibration plate and returning to the lidar and the corresponding theoretical flight time, and calibrating the lidar based on the difference.

[0050] The beneficial effects of this invention are:

[0051] This invention relates to a calibration device and method for lidar used in architectural design. In the calibration process, when the calibration distance is short, the calibration plates are in their first working state. When the distances between N calibration plates and the lidar are equal, the lidar can obtain N sets of measurement data in one rotation. Furthermore, with the distance between the calibration plates and the lidar remaining constant, the N sets of data can be cross-referenced, resulting in high reliability. This shortens the lidar calibration time and improves calibration efficiency. When the distances between the N calibration plates and the lidar change continuously, the lidar can obtain N sets of continuously changing measurement data in one rotation, thus facilitating the calibration of lidar at different distances. This improves the calibration accuracy of the lidar while realistically simulating operating conditions. When the calibration distance is long, the calibration plate is in a second working state, allowing the laser beam emitted by the lidar to return to the lidar after being reflected by at least two calibration plates. This increases the measurement distance and makes the operating conditions more realistic, thus helping to improve the calibration accuracy of the lidar. The lidar calibration method for architectural design includes calibrating the lidar according to the first working mode when the second working mode is true, provided that the first relation holds. When the second relation does not hold, the lidar is calibrated according to the second working mode. This allows for different working modes to be adopted according to different situations, thereby improving the applicability of the lidar calibration method for architectural design. Attached Figure Description

[0052] Figure 1 This is a three-dimensional structural schematic diagram of a lidar calibration device for architectural design provided in an embodiment of the present invention;

[0053] Figure 2 To simplify the operation of the laser radar calibration device for architectural design when the number of calibration plates provided in one embodiment of the present invention is ten. Figure 1 ;

[0054] Figure 3 To simplify the operation of the laser radar calibration device for architectural design when the number of calibration plates provided in one embodiment of the present invention is ten. Figure 2 ;

[0055] Figure 4 To simplify the operation of the laser radar calibration device for architectural design when the number of calibration plates provided in one embodiment of the present invention is ten. Figure 3 ;

[0056] Figure 5 This is a flowchart illustrating a laser radar calibration method for architectural design, provided in an embodiment of the present invention.

[0057] in:

[0058] 100. Base; 101. Cylinder block;

[0059] 200. LiDAR; 201. Transmitter; 202. Receiver;

[0060] 300, bracket; 301, calibration plate. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0062] The serial numbers assigned to components in this document, such as "first," "second," etc., are merely used to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0063] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0064] like Figure 1As shown, an embodiment of the present invention provides a calibration device for a laser radar 200 used for architectural design. In this embodiment, the calibration device includes a cylindrical base 100, a laser radar 200, and calibration plates 301. The laser radar 200 is cylindrical and is coaxially mounted on the top of the base 100 during use, and can rotate around its own axis. A transmitter 201 and a receiver 202 are provided on the peripheral wall of the laser radar 200. The transmitter 201 and the receiver 202 are set at the same height. The transmitter 201 is used to emit a laser beam, and the receiver 202 is used to receive the laser beam and measure the laser beam to obtain measurement parameters. There are N calibration plates 301, which are evenly distributed along the circumferential direction on the outer peripheral wall of the base 100. Each calibration plate 301 is set at the same height as the transmitter 201, and each calibration plate 301 can rotate around its own axis. Sliding along the radial direction of the base 100, the calibration plate 301 is used to reflect the laser beam emitted by the lidar 200 back to the lidar 200, so that the lidar 200 can measure the laser beam and obtain measurement parameters. The calibration plate 301 is rotatably mounted on the base 100 along a first axis and has corresponding first and second working states before and after rotation. The first axis is parallel to the axis of the base 100. Before rotation, the reflective surface of the calibration plate 301 is perpendicular to the laser beam emitted by the lidar 200, and the calibration plate 301 is in the first working state. The calibration distance between N calibration plates 301 and the lidar 200 is equal or the distance between N calibration plates 301 and the lidar 200 continuously changes to the calibration distance. After rotation, the calibration plate 301 is in the second working state, and the laser beam emitted by the lidar 200 returns to the lidar 200 after being reflected by at least two calibration plates 301.

[0065] Taking a calibration plate 301 with ten plates as an example, during the calibration of the lidar 200, when the calibration distance is short, the calibration plate 301 is in its first working state, with the reflective surfaces of all ten calibration plates 301 perpendicular to the laser beam emitted by the lidar 200. The distance between the ten calibration plates 301 and the lidar 200 can be adjusted as needed to be equal to the calibration distance, or the distance between the ten calibration plates 301 and the lidar 200 can be continuously varied to reach the calibration distance. When the distance between the ten calibration plates 301 and the lidar 200 is equal... At the calibration distance, the lidar 200 emits a laser beam through the transmitter 201 while rotating. During the rotation of the lidar 200, when the laser beam is perpendicular to the reflective surface of any one of the calibration plates 301, the laser beam is reflected back to the lidar 200 from the surface of that calibration plate 301. Simultaneously, the lidar 200 receives the laser beam through the receiver 202 and measures it to obtain measurement parameters. After the lidar 200 completes one rotation, the receiver 202 receives a total of ten sets of measurement parameters. Furthermore, under the premise that the distance between the calibration plate 301 and the lidar 200 remains constant, the ten sets of data can be compared with each other, resulting in high reliability. This shortens the calibration time of the lidar 200 while improving its calibration efficiency. When the distance between the ten calibration plates 301 and the lidar 200 continuously changes to the calibration distance, the lidar 200 rotates while emitting a laser beam through the transmitter 201. During the rotation of the lidar 200, when the lidar 200 rotates to the point where the laser beam reflects off any one of the calibration plates 301... When the surface is perpendicular, the laser beam is reflected from the surface of the calibration plate 301 back to the lidar 200. At the same time, the lidar 200 receives the laser beam through the receiver 202 and measures it to obtain measurement parameters. When the lidar 200 rotates to the calibration distance between the calibration plate 301 and the lidar 200, the receiver 202 receives multiple sets of continuously changing measurement data, which helps to calibrate the lidar 200 at different distances. This improves the calibration accuracy of the lidar 200 while realistically simulating the working conditions.

[0066] When the calibration distance is relatively far, the calibration plate 301 is in the second working state, which allows the laser beam emitted by the lidar 200 to return to the lidar 200 after being reflected by at least two calibration plates 301. This increases the measurement distance and makes the operating conditions more realistic, thereby helping to improve the calibration accuracy of the lidar 200.

[0067] Specifically, to facilitate the connection between the calibration plate 301 and the base 100, N cylinders 101 are evenly distributed on the outer peripheral wall of the base 100. Each cylinder 101 extends radially along the base 100. A bracket 300 is slidably inserted into each cylinder 101. The bracket 300 is L-shaped and has a horizontal section and a vertical section perpendicular to the horizontal section. The horizontal section is inserted into the cylinder 101, and the vertical section is set vertically upwards with the end of the vertical section away from the horizontal section at the same height as the transmitter 201. The calibration plate 301 and the bracket 300 are arranged in a one-to-one correspondence. The middle of both ends of the calibration plate 301 along the vertical direction is hinged to the end of the vertical section away from the horizontal section. The first axis is the line connecting the middle of the two ends of the calibration plate 301 along the vertical direction. The axis of rotation of the calibration plate 301 is parallel to the axis of the base 100.

[0068] Specifically, to provide the driving force for the LiDAR 200 to rotate, a drive motor is provided at the top center of the base 100. The output shaft of the drive motor is set upward and a rotating disk is sleeved on it. The top of the rotating disk is provided with a groove that engages with the bottom of the LiDAR 200 to drive the LiDAR 200 to rotate.

[0069] In some embodiments, the measurement parameters include at least the flight time of the laser beam; the flight time error can be obtained based on the flight time of the laser beam and the corresponding theoretical flight time, and the lidar 200 can be calibrated based on the error.

[0070] In this embodiment, multiple measurements can be taken to obtain multiple time-of-flight errors under a certain beam pulse time width. By subtracting the maximum and minimum values ​​of the time-of-flight errors under the same beam pulse time width, the jitter value of the time-of-flight error under a certain beam pulse time width can be obtained. Thus, the dispersion of single-point measurement of the lidar 200 under different beam pulse time widths can be obtained, which is convenient for calibrating the lidar 200.

[0071] In some embodiments, the laser radar calibration device for architectural design is further configured to include a driving member, which provides a driving force for the calibration plate 301 to slide radially along the base 100. In this embodiment, the driving member is configured as a hydraulic cylinder or a pneumatic cylinder, which is used to inject or depress hydraulic oil or gas between the cylinder body 101 and the support 300 to drive the calibration plate 301 to slide radially along the base 100 via the support 300, thereby changing the distance between the calibration plate 301 and the laser radar 200. In use, when the hydraulic cylinder or pneumatic cylinder injects hydraulic oil or gas between the cylinder body 101 and the support 300, the hydraulic or pneumatic cylinder provides a driving force for the calibration plate 301 to slide radially along the base 100, thereby changing the distance between the calibration plate 301 and the laser radar 200. Under the action of the support 300, the support 300 moves away from the base 100. The support 300 simultaneously drives the calibration plate 301 to move away from the base 100 to increase the distance between the calibration plate 301 and the lidar 200. When the hydraulic cylinder or pneumatic cylinder draws hydraulic oil or gas from between the cylinder body 101 and the support 300, the pressure outside the cylinder body 101 is greater than the pressure inside the cylinder body 101. Under the action of the pressure difference between the inside and outside of the cylinder body 101, the support 300 moves closer to the base 100. The support 300 simultaneously drives the calibration plate 301 to move closer to the base 100 to decrease the distance between the calibration plate 301 and the lidar 200.

[0072] In other embodiments, the driving component can also be an electric cylinder, which is disposed inside the cylinder body 101 to provide driving force for the calibration plate 301 to slide in the radial direction of the base 100. The end of the electric cylinder away from the output shaft is fixedly connected to the end of the cylinder body 101 near the base 100 by bolts. The output shaft of the electric cylinder extends in the radial direction of the base 100 and is fixedly connected to the end of the bracket 300 away from the calibration plate 301. In use, when the output shaft of the electric cylinder extends, it drives the bracket 300 to move away from the base 100. The bracket 300 simultaneously drives the calibration plate 301 to move in the direction away from the base 100 to increase the distance between the calibration plate 301 and the lidar 200. When the output shaft of the electric cylinder retracts, it drives the bracket 300 to move in the direction closer to the base 100. The bracket 300 simultaneously drives the calibration plate 301 to move in the direction closer to the base 100 to decrease the distance between the calibration plate 301 and the lidar 200.

[0073] like Figure 5 As shown, one embodiment of the present invention also provides a calibration method for a lidar used in architectural design, employing a lidar calibration device for architectural design, with the radius of the base set as r, as follows... Figure 2 As shown, taking a calibration plate count of ten as an example, the included angle between adjacent calibration plates is... The distance between the calibration plate and the outer peripheral wall of the base is S, and the minimum value of S is The maximum value of S is The minimum distance between the calibration board and the lidar is The maximum distance is The calibration distance between the calibration board and the lidar is... The calibration method for LiDAR used in architectural design includes the following steps:

[0074] Step S100: Determine whether the first relation is true. The first relation is: ;

[0075] Specifically, The closest test distance that a lidar calibration device used in architectural design can measure. To achieve the maximum central angle formed by the calibration plates refracting twice, when N equals ten, This is the farthest test distance at which the laser beam emitted by the lidar can undergo two reflections, obtained according to the law of cosines. When the first relationship holds true, it means that the calibration distance between the calibration plate and the lidar is within the test range of the lidar calibration device for architectural design, and the lidar calibration device for architectural design can calibrate the lidar. When the first relationship does not hold true, it means that the calibration distance between the calibration plate and the lidar is outside the test range of the lidar calibration device for architectural design, and the lidar calibration device for architectural design cannot calibrate the lidar.

[0076] Step S200: When the first relation is true, determine whether the second relation is true. The second relation is... ;

[0077] Specifically, assuming the first relation holds, this indicates that the calibration distance between the calibration plate and the lidar is within the test range of the lidar calibration device for architectural design, and the lidar calibration device for architectural design can calibrate the lidar. In this case, it is necessary to... The size determines the operating mode of the lidar calibration device used in architectural design, among which The farthest test distance that a lidar calibration device for architectural design can measure in the first operating mode.

[0078] Step S300: If successful, calibrate the lidar according to the first working mode;

[0079] Specifically, when Upon its establishment, it was stated that the LiDAR calibration device for architectural design was capable of calibrating the LiDAR in its first operating mode. The value is relatively small, so the lidar is calibrated according to the first working mode.

[0080] If step S400 is not successful, the lidar is calibrated according to the second working mode.

[0081] Specifically, when If this condition is not met, it indicates that the lidar calibration device for architectural design cannot calibrate the lidar in the first operating mode. The value is relatively large, so the lidar is calibrated according to the second working mode.

[0082] In a further embodiment, in the first operating mode, the distance between each calibration board and the lidar is the calibration distance. When this happens, follow these steps:

[0083] In step S310, the lidar rotates while emitting a laser beam;

[0084] Specifically, the calibration plate is moved by the bracket until the distance between the calibration plate and the lidar is... Then, while rotating, the lidar emits a laser beam through the transmitter. During the rotation of the lidar, when the lidar rotates to the point where the laser beam is perpendicular to the reflective surface of any of the calibration plates, the laser beam is reflected back to the lidar from the surface of that calibration plate.

[0085] Step S320: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar.

[0086] Specifically, the lidar receives the laser beam through a receiver and measures the laser beam to obtain the time of flight of the laser beam.

[0087] Step S330: After the lidar rotates a preset number of times, the lidar is calibrated.

[0088] Specifically, after the lidar rotates a preset number of times, it obtains a set of measurement data in the form of ten preset circles. Under the premise that the distance between the calibration plate and the lidar remains unchanged, the measurement data in the form of ten preset circles can be compared with each other, and the reliability is high. At this time, calibrating the lidar helps to improve the calibration efficiency of the lidar.

[0089] In other embodiments, in the first operating mode, the distance between the N calibration boards and the lidar continuously varies to the calibration distance. At that time, the distance the calibration plate slides in the radial direction along the base in one go is set as follows: Initially, the distance between the first calibration board and the lidar is... Along the same circumferential direction of the base, the distance between the i-th calibration plate and the lidar is Let i = 1, 2 to N; taking ten calibration boards as an example, the calibration boards are moved by the bracket so that the distance between the first calibration board and the lidar is... And along the clockwise direction of the base, the distance between the second calibration plate and the lidar is... The distance between the third calibration board and the lidar is The distance between the fourth calibration board and the lidar is The distance between the fifth calibration board and the lidar is The distance between the sixth calibration board and the lidar is The distance between the seventh calibration board and the lidar is The distance between the eighth calibration board and the lidar is The distance between the ninth calibration board and the lidar is The distance between the tenth calibration board and the lidar is .

[0090] And follow these steps:

[0091] In step S340, the lidar rotates while emitting a laser beam, and after the lidar scans the i-th calibration plate again, the i-th calibration plate slides a distance away from the axis of the base along the radial direction of the base. , i=1, 2 to N;

[0092] Specifically, the calibration plates are moved by the support frame. The lidar rotates clockwise while emitting a laser beam through the transmitter. During the lidar's rotation, when the laser beam is perpendicular to the reflective surface of any one of the calibration plates, the laser beam is reflected back to the lidar from that surface. Furthermore, after the lidar scans the i-th calibration plate again, the i-th calibration plate slides a distance along the radial direction of the base away from the axis of the base. Taking the first calibration plate as an example, when the lidar scans the first calibration plate again, the distance the first calibration plate slides along the radial direction of the base away from the axis of the base is... The distance between the first calibration board and the lidar is... This allows the distance between the calibration board and the lidar to change continuously.

[0093] Step S350: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar.

[0094] Specifically, the lidar receives the laser beam through a receiver and measures the laser beam to obtain the time of flight of the laser beam.

[0095] Step S360, when At that time, the lidar is calibrated.

[0096] Specifically, during the rotation of the lidar, the distance between the calibration plate it scans and the lidar changes accordingly. When the distance between the calibration board and the lidar is at the calibration distance, the receiver receives multiple sets of continuously changing measurement data, thus achieving a true simulation of the operating conditions. Calibrating the lidar at this time helps improve its calibration accuracy.

[0097] In other embodiments, the second operating mode is the calibration distance between each calibration board and the lidar. At that time, the distance between the first calibration board and the lidar was set to... The distance between the q-th calibration board and the lidar is The distance between the first calibration plate and the qth calibration plate is The central angle formed by the first calibration plate and the q-th calibration plate is the largest, and this central angle is... , Initially, the distance between all calibration boards and the lidar was... ,but According to the Law of Cosines, we can obtain Taking a calibration board quantity of ten as an example, such as Figure 2 As shown, the central angle formed by the first calibration plate and the fifth calibration plate in the counterclockwise direction is the largest. And the distance between the first calibration board and the lidar is The distance between the fifth calibration plate and the lidar in the counterclockwise direction is The distance between the first calibration plate and the fifth calibration plate in the counterclockwise direction is The distance between the ten calibration plates and the lidar is adjusted to be equal using a bracket. Following step S400, the following steps are also included:

[0098] Step S410, when hour,

[0099] Calculate the included angle ;

[0100] Specifically, when This means that the distance traveled by the laser beam emitted by the lidar after being reflected by the first calibration plate and the fifth calibration plate in a counter-clockwise direction is the calibration distance. At this point, the angle B between the line connecting the first calibration plate and the fifth calibration plate in the counterclockwise direction and the line connecting the fifth calibration plate and the lidar in the counterclockwise direction can be calculated using the law of cosines.

[0101] Step S420, calculate the included angle ;

[0102] Specifically, the angle A between the line connecting the first calibration plate and the fifth calibration plate in the counterclockwise direction and the line connecting the first calibration plate and the lidar can be calculated using the law of cosines.

[0103] Step S430, when At that time, the distance the q-th calibration plate slides along the radial direction of the base. ,at this time At this time, the distance between the q-th calibration plate and the lidar is , , This is the distance between the first calibration plate and the qth calibration plate at this time, and Calculate the included angles A and B;

[0104] Specifically, when At times, such as Figure 3 As shown, the distance by which the q-th calibration plate slides along the radial direction of the base can be adjusted to increase the... The value of is such that the distance the laser beam emitted by the lidar travels after being reflected by the first calibration plate and the fifth calibration plate in a counterclockwise direction is the calibration distance. Set the distance the q-th calibration plate slides along the radial direction of the base. ,at this time , = ,at this time , then according to Calculate The value, and then can be based on The values ​​of angle A and angle B are calculated using the law of cosines.

[0105] Step S431: Adjust the angle between the reflective surfaces of all the calibration plates and the laser beam emitted by the lidar according to angles A and B;

[0106] Specifically, the angle between the reflective surfaces of the first, second, third, and fourth calibration plates (counterclockwise), and the laser beam emitted by the lidar is adjusted according to angle A. Similarly, the angle between the reflective surfaces of the fifth, sixth, seventh, and eighth calibration plates (counterclockwise), and the laser beam emitted by the lidar is adjusted according to angle B. This ensures that the laser beam emitted by the lidar is reflected by the first calibration plate to the fifth calibration plate (counterclockwise). The light is reflected from the fifth calibration plate in a counter-clockwise direction and returns to the lidar. It is then reflected from the second calibration plate in a counter-clockwise direction to the sixth calibration plate in a counter-clockwise direction, and then reflected from the sixth calibration plate in a counter-clockwise direction and returns to the lidar. It is then reflected from the third calibration plate in a counter-clockwise direction to the seventh calibration plate in a counter-clockwise direction, and then reflected from the seventh calibration plate in a counter-clockwise direction and returns to the lidar. Finally, it is reflected from the fourth calibration plate in a counter-clockwise direction to the eighth calibration plate in a counter-clockwise direction and returns to the lidar.

[0107] In step S440, the lidar rotates while emitting a laser beam;

[0108] Specifically, the lidar emits a laser beam through its transmitter while rotating. During the lidar's rotation, when the laser beam contacts the reflective surfaces of the first, second, third, and fourth calibration plates (counterclockwise), it is reflected back to the corresponding calibration plate's reflective surface, and then reflected again to return to the lidar. Similarly, when the laser beam contacts the reflective surfaces of the fifth, sixth, seventh, and eighth calibration plates (counterclockwise), it is reflected back to the corresponding calibration plate's reflective surface, and then reflected again to return to the lidar.

[0109] Step S441: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar.

[0110] Specifically, the lidar receives the laser beam through a receiver and measures the laser beam to obtain the time of flight of the laser beam.

[0111] Step S442: After the lidar rotates a preset number of times, the lidar is calibrated.

[0112] Specifically, after the lidar rotates a preset number of times, multiple sets of measurement data can be obtained. Under the premise that the distance between the calibration plate and the lidar remains unchanged, the multiple sets of measurement data can be compared with each other, and the reliability is high. At this time, calibrating the lidar helps to improve the calibration efficiency of the lidar.

[0113] In a further embodiment, the radius of the lidar is set to... After step S410, the method further includes:

[0114] Step S411: Calculate the perpendicular distance from the laser radar to the line connecting the first calibration plate and the qth calibration plate. ;

[0115] Specifically, because the lidar itself has dimensions, to avoid the lidar itself blocking the laser beam emitted by the lidar, it is necessary to calculate the perpendicular distance from the lidar to the line connecting the first calibration plate and the qth calibration plate, such as... Figure 1 As shown, .

[0116] Step S412, when When calculating the included angle ;

[0117] Specifically, when When this occurs, it indicates that the laser beam emitted by the lidar will not be blocked by the lidar, and the angle can then be calculated. .

[0118] Step S413, when At that time, the central angle formed by the first calibration plate and the (q-1)th calibration plate is , The distance between the first calibration plate and the lidar The distance between the (q-1)th calibration plate and the lidar The distance between the first calibration plate and the (q-1)th calibration plate Proceed through steps S410 to S442.

[0119] Specifically, when This indicates that the laser beam emitted by the lidar will be blocked by the lidar. In this case, it is necessary to change the calibration plate to the one to which the laser beam arrives after being reflected from the first calibration plate. Taking ten calibration plates as an example, ... Figure 4 As shown, the central angle formed by the first calibration plate and the fourth calibration plate in the counterclockwise direction is... The distance between the first calibration board and the lidar The distance between the (q-1)th calibration board and the lidar Furthermore, the distance between the first calibration plate and the (q-1)th calibration plate can be obtained using the law of cosines. Then, by executing steps S410 to S442, multiple sets of measurement data can be obtained.

[0120] In other embodiments, the second operating mode continuously varies the distance between the N calibration boards and the lidar to the calibration distance. At that time, the distance between the first calibration board and the lidar was set to... The distance between the q-th calibration board and the lidar is The distance between the first calibration plate and the qth calibration plate is The central angle formed by the first calibration plate and the q-th calibration plate is the largest, and this central angle is... , Initially, the distance between all calibration boards and the lidar was... ,but According to the Law of Cosines, we can obtain Taking a calibration board quantity of ten as an example, such as Figure 2 As shown, the central angle formed by the first calibration plate and the fifth calibration plate in the counterclockwise direction is the largest. And the distance between the first calibration board and the lidar is The distance between the fifth calibration plate and the lidar in the counterclockwise direction is The distance between the first calibration plate and the fifth calibration plate in the counterclockwise direction is When the distance between the ten calibration plates and the lidar is continuously varied by adjusting the bracket, the second working mode also includes the following steps:

[0121] Step S450, when hour,

[0122] Calculate the included angle ;

[0123] Specifically, when When the laser beam emitted by the lidar is reflected by the first calibration plate and the fifth calibration plate in a counterclockwise direction, the distance the laser beam travels is _____. At this point, the angle B between the line connecting the first calibration plate and the fifth calibration plate in the counterclockwise direction and the line connecting the fifth calibration plate and the lidar in the counterclockwise direction can be calculated using the law of cosines.

[0124] Step S460, calculate the included angle ;

[0125] Specifically, the angle A between the line connecting the first calibration plate and the fifth calibration plate in the counterclockwise direction and the line connecting the first calibration plate and the lidar can be calculated using the law of cosines.

[0126] Step S470, when At that time, the distance the first calibration plate slides along the radial direction of the base. ,at this time , , This is the distance between the first calibration plate and the qth calibration plate at this time, and Calculate the included angles A and B;

[0127] Specifically, when At this point, the distance by which the first calibration plate slides radially along the base can be increased. The value of is such that the distance traveled by the laser beam emitted by the lidar after reflection from the first calibration plate and the fifth calibration plate in the counterclockwise direction is . Set the distance the first calibration plate slides radially along the base. ,at this time , = ,at this time , then according to Calculate The value, and then can be based on The values ​​of angle A and angle B are calculated using the law of cosines.

[0128] Step S471: Adjust the angle between the reflective surfaces of all the calibration plates and the laser beam emitted by the lidar according to angles A and B;

[0129] Specifically, the angle between the reflective surfaces of the first, second, third, and fourth calibration plates (counterclockwise), and the laser beam emitted by the lidar is adjusted according to angle A. Similarly, the angle between the reflective surfaces of the fifth, sixth, seventh, and eighth calibration plates (counterclockwise), and the laser beam emitted by the lidar is adjusted according to angle B. This ensures that the laser beam emitted by the lidar is reflected by the first calibration plate to the fifth calibration plate (counterclockwise), and then... The laser beam reflects off the first calibration plate and returns to the lidar. It then reflects off the second calibration plate (counter-clockwise) and reaches the sixth calibration plate (counter-clockwise). After reflecting off the sixth calibration plate, it returns to the lidar. It then reflects off the third calibration plate (counter-clockwise) and reaches the seventh calibration plate (counter-clockwise). After reflecting off the seventh calibration plate, it returns to the lidar. It then reflects off the fourth calibration plate (counter-clockwise) and reaches the eighth calibration plate (counter-clockwise). Finally, the laser beam travels a distance between the first calibration plate and the fifth calibration plate (counter-clockwise). The distance traveled on the second calibration plate and the sixth calibration plate in the counterclockwise direction is... The distance traveled on the third calibration plate and the seventh calibration plate in the counterclockwise direction is... The distance traveled on the fourth calibration plate and the eighth calibration plate in the counterclockwise direction is... , and so on, in a loop.

[0130] In step S480, the lidar rotates while emitting a laser beam; and after the lidar scans the i-th calibration plate again, the i-th calibration plate slides a distance away from the axis of the base along the radial direction of the base. , i=1, 2 to N;

[0131] Specifically, the calibration plates are moved by the support bracket. The lidar rotates clockwise while emitting a laser beam through the transmitter. During the lidar's rotation, when the laser beam contacts the reflective surfaces of the first, second, third, and fourth calibration plates (counterclockwise), it is reflected to the corresponding reflective surface of the calibration plate, and then reflected back to the lidar. Similarly, when the laser beam contacts the reflective surfaces of the fifth, sixth, seventh, and eighth calibration plates (counterclockwise), it is reflected to the corresponding reflective surface of the calibration plate, and then reflected back to the lidar.

[0132] And when the lidar scans the i-th calibration plate again, the distance the i-th calibration plate slides along the radial direction of the base away from the axis of the base is... Let i = 1, 2 to N. Taking the first calibration plate as an example, when the lidar scans the first calibration plate again, the distance the first calibration plate slides along the radial direction of the base away from the axis of the base is... The distance between the first calibration board and the lidar is... This allows the distance between the calibration board and the lidar to change continuously.

[0133] Step S481: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar.

[0134] Specifically, the lidar receives the laser beam through a receiver and measures the laser beam to obtain the time of flight of the laser beam.

[0135] Step S482, when At that time, the lidar is calibrated.

[0136] Specifically, during the rotation of the lidar, the distance between the calibration plate it scans and the lidar changes accordingly. When the distance between the calibration board and the lidar is at the calibration distance, the receiver receives multiple sets of continuously changing measurement data, thus achieving a true simulation of the operating conditions. Calibrating the lidar at this time helps improve its calibration accuracy.

[0137] In other embodiments, steps S411 to S413 can be performed similarly to prevent the laser beam emitted by the lidar from being blocked by the lidar itself.

[0138] In a further embodiment, the lidar is calibrated by calculating the difference between the flight time of the laser beam after reflection from each calibration plate and its return to the lidar and the corresponding theoretical flight time, and then calibrating the lidar based on this difference.

[0139] In this embodiment, multiple measurements can be taken to obtain multiple time-of-flight errors under a certain beam pulse time width. By subtracting the maximum and minimum values ​​of the time-of-flight errors under the same beam pulse time width, the jitter value of the time-of-flight error under a certain beam pulse time width can be obtained. Thus, the dispersion of single-point measurement of the lidar under test under different beam pulse time widths can be obtained, which is convenient for calibrating the lidar.

[0140] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0141] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for calibrating a lidar system used in architectural design, characterized in that, A lidar calibration device for architectural design is adopted, the lidar calibration device for architectural design comprising: The laser radar is coaxially mounted on the top of the cylindrical base and can rotate around its own axis during use. The calibration plate comprises N calibration plates, which are evenly distributed along the circumferential direction on the outer peripheral wall of the base. Each calibration plate is set at the same height as the lidar and can slide along the radial direction of the base. The calibration plate is used to reflect the laser beam emitted by the lidar back to the lidar so that the lidar can measure the laser beam and obtain measurement parameters. The calibration plate is rotatably mounted on the base along a first axis and has corresponding first and second working states before and after rotation. The first axis is parallel to the axis of the base. Before rotation, the reflective surface of the calibration plate is perpendicular to the laser beam emitted by the lidar. The calibration plate is in the first working state, and the calibration distance between N calibration plates and the lidar is equal or the distance between N calibration plates and the lidar continuously changes to the calibration distance. After rotation, the calibration plate is in the second working state, and the laser beam emitted by the lidar returns to the lidar after being reflected by at least two calibration plates. Wherein, the radius of the base is r; the distance between the calibration plate and the outer peripheral wall of the base is S, and the minimum value of S is... The maximum value of S is The minimum distance between the calibration board and the lidar is The maximum distance is The calibration distance between the calibration board and the lidar is... The laser radar calibration method for architectural design includes the following steps: Step S100: Determine whether the first relation is true. The first relation is: ; Step S200: When the first relation is true, determine whether the second relation is true. The second relation is... ; Step S300: If successful, calibrate the lidar according to the first working mode; In the first operating mode, the distance between each calibration board and the lidar is the calibration distance. When this happens, follow these steps: In step S310, the lidar rotates while emitting a laser beam; Step S320: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar. Step S330: After the lidar rotates a preset number of times, the lidar is calibrated. If step S400 is not successful, the lidar is calibrated according to the second working mode; In the second operating mode, the distance between the first calibration board and the lidar is set to... The distance between the q-th calibration plate and the lidar is The distance between the first calibration plate and the qth calibration plate is The central angle formed by the first calibration plate and the qth calibration plate is the largest, and this central angle is... , Initially, the distance between all the calibration boards and the lidar is... ,but , And follow these steps: Step S410, when hour, Calculate the included angle ; Step S420, calculate the included angle ; Step S430, when At that time, the distance the q-th calibration plate slides along the radial direction of the base. ,at this time At this time, the distance between the q-th calibration plate and the lidar is , , This is the distance between the first calibration plate and the qth calibration plate at this time, and Calculate the included angles A and B; Step S431: Adjust the angle between the reflective surfaces of all the calibration plates and the laser beam emitted by the lidar according to angles A and B; In step S440, the lidar rotates while emitting a laser beam; Step S441: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar. Step S442: After the lidar rotates a preset number of times, the lidar is calibrated.

2. The laser radar calibration method for architectural design according to claim 1, characterized in that, In the first operating mode, the distance between the N calibration boards and the lidar continuously changes to the calibration distance. At that time, the distance that the calibration plate slides in one radial direction along the base is set to be Initially, the distance between the first calibration board and the lidar is... Along the same circumferential direction of the base, the distance between the i-th calibration plate and the lidar is i = 1, 2 to N; and follow these steps: In step S340, the lidar rotates while emitting a laser beam, and after the lidar scans the i-th calibration plate again, the i-th calibration plate slides a distance away from the axis of the base along the radial direction of the base. , i=1, 2 to N; Step S350: Record the flight time of the laser beam emitted by the lidar after being reflected by each of the calibration plates and returning to the lidar. Step S360, when At that time, the lidar is calibrated.

3. The laser radar calibration method for architectural design according to claim 1, characterized in that, The radius of the lidar is ; Following step S410, the method further includes: Step S411: Calculate the perpendicular distance from the laser radar to the line connecting the first calibration plate and the qth calibration plate. ; Step S412, when When calculating the included angle ; Step S413, when At that time, the central angle formed by the first calibration plate and the (q-1)th calibration plate is , The distance between the first calibration plate and the lidar The distance between the (q-1)th calibration plate and the lidar The distance between the first calibration plate and the (q-1)th calibration plate Proceed through steps S410 to S442.

4. The laser radar calibration method for architectural design according to claim 1, characterized in that, The calibration method for the lidar includes calculating the difference between the flight time of the laser beam after being reflected by each calibration plate and returning to the lidar and the corresponding theoretical flight time, and calibrating the lidar based on the difference.

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