Test method, test system and computer readable storage medium
By introducing a target board and a rangefinder into the lidar system and dynamically calibrating the ranging error, the reliability problem of lidar distance accuracy testing was solved, accurate ranging was achieved under pose deviation conditions, and the safety performance of autonomous driving was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HESAI TECH CO LTD
- Filing Date
- 2024-11-12
- Publication Date
- 2026-05-12
AI Technical Summary
Existing LiDAR distance accuracy testing methods have biases, affecting the accuracy of ranging performance judgments. In particular, when there is a deviation between the target board pose and the preset pose, the test results are not reliable enough.
By introducing a target board and a rangefinder into the lidar system, the range and distance calibration values are determined using points in the lidar point cloud. Combined with the distance values measured by the rangefinder, the ranging error of the lidar is dynamically calibrated in real time. The test method is executed by a controller to reduce manpower and equipment costs.
It improves the accuracy and reliability of lidar ranging results, and can accurately determine ranging errors when the target board's pose is deviated, thereby enhancing perception accuracy and safety performance in scenarios such as autonomous driving.
Smart Images
Figure CN122017802A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of lidar, and more particularly to a test method, a test system, and a computer-readable storage medium. Background Technology
[0002] LiDAR (Light Detection and Ranging) is a radar system that uses laser beams to detect the position, velocity, and other characteristics of targets. It is an advanced detection method that combines laser technology with photoelectric detection technology. Due to its advantages such as high resolution, good concealment, strong resistance to active interference, good low-altitude detection performance, small size, and light weight, LiDAR is widely used in fields such as autonomous driving, transportation communication, drones, intelligent robots, and resource exploration.
[0003] Before a lidar device leaves the factory, its distance accuracy can be tested. This test determines whether the lidar's performance meets the usage standards. If the distance accuracy testing method itself is flawed, it will directly affect the judgment of the lidar's distance accuracy performance. Therefore, a more reliable lidar ranging accuracy testing method is urgently needed.
[0004] The content of the background section is merely the technology known to the inventor and does not necessarily represent the prior art in this field. Summary of the Invention
[0005] To address one or more of the problems existing in the prior art, this disclosure provides a testing method for a lidar, comprising: determining a ranging value based on points in the lidar point cloud; determining a distance calibration value based on a first distance from a first measurement point to a target board and a second distance from a second measurement point to the target board; and determining the ranging error of the lidar based on the ranging value and the distance calibration value.
[0006] Optionally, determining the distance calibration value includes: determining the perpendicular distance between the lidar and the target plate based on the first distance and the second distance; and determining the distance calibration value based on the perpendicular distance and the included angle, wherein the included angle is the angle between the direction vector of the point and the direction vector of the perpendicular.
[0007] Optionally, determining the perpendicular distance between the lidar and the target plate includes: determining the perpendicular distance based on the first distance, the second distance, and the third distance, wherein the third distance is the distance between the first measurement point and the second measurement point.
[0008] Optionally, the testing method further includes: determining the included angle, including: determining a first coordinate value of the point in the lidar coordinate system; determining a second coordinate value of the perpendicular foot in the lidar coordinate system; and determining the included angle based on the first coordinate value and the second coordinate value.
[0009] Optionally, the lidar includes a detection channel, the point cloud includes points corresponding to the detection channel, and determining the ranging error of the lidar includes determining the ranging error of the detection channel.
[0010] Optionally, the point cloud includes multiple points corresponding to the detection channel, and determining the ranging error of the detection channel includes: determining the average value and / or root mean square error of the difference between the ranging value and the distance calibration value of the multiple points corresponding to the detection channel; and determining the ranging error of the detection channel based on the average value and / or root mean square error.
[0011] Optionally, the lidar includes multiple detection channels, and determining the ranging error of the detection channels includes determining the ranging error of the multiple detection channels.
[0012] Optionally, the testing method further includes: determining the performance parameters of the lidar based on the ranging error, wherein the performance parameters include at least one of distance accuracy or distance precision.
[0013] Optionally, the testing method further includes: measuring the first distance using a first rangefinder whose light emission direction is parallel to the positive emission direction of the lidar; and measuring the second distance using a second rangefinder whose light emission direction is parallel to the positive emission direction of the lidar.
[0014] Optionally, the first rangefinder and the second rangefinder are symmetrically arranged on both sides of the lidar.
[0015] This disclosure also provides a testing system for a lidar, comprising: a target board located in the light emission direction of the lidar; a rangefinder disposed on the side of the lidar; and a controller; the controller being configured to perform the testing method described above.
[0016] This disclosure also provides a computer-readable storage medium including computer-executable instructions stored thereon, which, when executed by a processor, perform the test method described above.
[0017] The testing method disclosed herein determines the ranging value based on points in the LiDAR point cloud. It accurately determines the distance calibration value based on a first distance from a first measurement point to the target board and a second distance from a second measurement point to the target board. By combining the ranging value and the accurate distance calibration value, the accuracy of the LiDAR's ranging error can be improved. Based on the accurate ranging error, the ranging performance of the LiDAR can be accurately corrected and compensated, improving the accuracy and reliability of the LiDAR ranging results. When LiDAR is applied in scenarios such as autonomous driving, it helps the LiDAR accurately perceive the environment, enhancing the safety performance of autonomous driving.
[0018] The test method disclosed herein can still dynamically and accurately determine the distance calibration value between the target board and the lidar when there is a deviation between the pose of the target board and the preset pose. This allows for accurate determination of the lidar's ranging error, thereby improving the reliability, flexibility, and robustness of lidar accuracy testing.
[0019] The test system disclosed herein can dynamically track the attitude of the target board in real time. Even if there is a deviation between the pose of the target board and the preset pose, it can still accurately determine the distance calibration value between the target board and the lidar. This helps to achieve accurate, reliable and robust lidar accuracy testing or calibration, and reduces the manpower and equipment cost input in the testing process. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be introduced as examples below. The drawings described below are merely embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. The drawings are used to provide a further understanding of this disclosure and constitute a part of the specification. They are used together with the embodiments of this disclosure to explain this disclosure and do not constitute a limitation of this disclosure. In the drawings:
[0021] Figure 1 A flowchart illustrating an exemplary test method consistent with some embodiments of this disclosure is shown.
[0022] Figure 2 A schematic diagram of an exemplary test system consistent with some embodiments of this disclosure is shown.
[0023] Figure 3 A partial schematic diagram of an exemplary test system consistent with some embodiments of the present disclosure is shown.
[0024] Figure 4 This diagram illustrates an exemplary target board whose pose, consistent with some embodiments of the present disclosure, does not deviate from a preset pose.
[0025] Figure 5 This diagram illustrates a deviation between the pose of an exemplary target board consistent with some embodiments of the present disclosure and a preset pose.
[0026] Figure 6 A schematic diagram illustrating an exemplary determination of distance calibration values is shown, consistent with some embodiments of this disclosure.
[0027] Figure 7 This diagram illustrates the lidar ranging results when the pose of an exemplary target board consistent with some embodiments of the present disclosure does not deviate from a preset pose.
[0028] Figure 8 This diagram illustrates the ranging results without range measurement performance correction compensation for the lidar when the pose of an exemplary target board, consistent with some embodiments of this disclosure, deviates from a preset pose.
[0029] Figure 9 This diagram illustrates the ranging results of correcting and compensating the ranging performance of a lidar using the ranging error determined by this disclosure when the pose of an exemplary target plate, consistent with some embodiments of this disclosure, deviates from a preset pose. Detailed Implementation
[0030] In the following description, only certain exemplary embodiments are shown. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this disclosure. Therefore, the drawings and description are to be considered exemplary in nature and not restrictive.
[0031] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship according to the accompanying drawings, and are only for the convenience of describing this disclosure and 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, and therefore should not be construed as a limitation of this disclosure. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.
[0032] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "coupling" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or connections that allow for communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.
[0033] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0034] The following provides numerous different embodiments or examples for implementing various structures of this disclosure. To simplify this disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit this disclosure. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, this disclosure provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0035] The following description, in conjunction with the accompanying drawings, illustrates some embodiments of this disclosure. It should be understood that the embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this disclosure.
[0036] This disclosure provides a testing method and testing system for lidar.
[0037] In the pre-shipment testing of lidar, distance accuracy testing is a crucial component. In some embodiments, a target plate can be used to test or calibrate the lidar's distance accuracy. The target plate can be a planar plate structure, with a preset reflectivity on the side facing the lidar. The target plate is placed at a certain distance from the lidar. The lidar initiates a scan to obtain the test distance of the target plate. The true distance between the target plate and the lidar can be determined using other precise ranging instruments. By comparing the deviation between the test distance and the true distance, the distance accuracy of the lidar can be determined. Optionally, the target plate can be mounted on a track, and the distance between the target plate and the lidar can be adjusted by controlling the track's movement, allowing for accuracy testing or calibration of the lidar at different distances. Optionally, multiple target plates can be used, each with different reflectivity settings, allowing for accuracy testing or calibration of the lidar at different reflectivity levels. During testing, the target plate can maintain a preset pose with the lidar, for example, the light emitted from the lidar's test channel is directly incident on the target plate, or forms a certain angle with the normal to the target plate. During the process of moving or switching target boards, the actual pose of the target board may deviate from the preset pose when it moves to the target position. This deviation will affect the true distance between the target board and the lidar, and thus affect the accuracy of the lidar distance accuracy test.
[0038] This disclosure provides a testing method and system for lidar. The testing method includes: determining a ranging value based on points in the lidar point cloud; determining a distance calibration value based on a first distance from a first measurement point to a target board and a second distance from a second measurement point to the target board; and determining the ranging error of the lidar based on the ranging value and the distance calibration value. The testing system includes: a lidar, a target board, a rangefinder, and a controller. The target board is located in the light emission direction of the lidar. The rangefinder is mounted on the side of the lidar. The controller can execute the testing method. The testing method and system of this disclosure can reliably test or calibrate the ranging accuracy of the lidar even when there is a deviation between the actual pose and the preset pose of the target board, and can reduce the manpower and equipment costs in the testing process. Details are described below.
[0039] Figure 1 A flowchart illustrating an exemplary test method 100 consistent with some embodiments of this disclosure is shown. Figure 1As shown, test method 100 includes steps S110 to S130. Step S110: Determine the ranging value based on points in the lidar point cloud. Step S120: Determine the distance calibration value based on a first distance from a first measurement point to the target board and a second distance from a second measurement point to the target board. Step S130: Determine the ranging error of the lidar based on the ranging value and the distance calibration value. The test method disclosed herein can accurately determine the ranging error of the lidar.
[0040] Figure 2 A schematic diagram of an exemplary test system 200 consistent with some embodiments of this disclosure is shown. Figure 2 As shown, the test system 200 includes a target board 210, a rangefinder, and a controller 230. The rangefinder may include a first rangefinder 220-1 and a second rangefinder 220-2. This test system can be used to test a lidar 300. The target board 210 is located within the detection range of the lidar 300. The target board 210 can be mounted on a track (not shown). This facilitates moving the target board's position. The controller 230 can control the target board 210 to move along the track, thereby changing the distance between the lidar 300 and the target board 210. This facilitates testing the lidar's ranging accuracy at different distances. In some embodiments, the lidar 300 can be mounted on a track. The controller 230 can control the lidar 300 to move along the track, thereby changing the distance between the lidar 300 and the target board 210. In some embodiments, the target board 210 or the lidar 300 can be mounted on a track, and the controller 230 can control the track to move, thereby changing the distance between the lidar 300 and the target board 210.
[0041] The first rangefinder 220-1 and the second rangefinder 220-2 can be positioned on opposite sides of the lidar 300. Optionally, the distance between the first rangefinder 220-1 and the lidar, and the distance between the second rangefinder 220-2 and the lidar, can be equal. This simplifies calculations. Alternatively, the distances between the first rangefinder 220-1 and the lidar, and the distances between the second rangefinder 220-2 and the lidar, can also be unequal. The first rangefinder 220-1 and the second rangefinder 220-2 can be laser rangefinders, lidar, or similar devices. The light emission direction of the rangefinders can be parallel to the positive emission direction of the lidar 300. The first rangefinder 220-1 can measure a first distance from a first measurement point (e.g., the position of the first rangefinder 220-1) to the target plate. The second rangefinder 220-2 can measure a second distance from a second measurement point (e.g., the position of the second rangefinder 220-2) to the target plate.
[0042] It should be noted that, Figure 2The first rangefinder 220-1 and the second rangefinder 220-2 shown are merely illustrative examples, and this disclosure is not intended to limit them. In some embodiments, a rangefinder can be used to measure a first distance from a first measuring point to a target board and a second distance from a second measuring point to a target board, all of which are within the scope of this disclosure.
[0043] The controller 230 can be a controller installed on equipment such as a lidar, vehicle, server, or computer. The controller 230 can execute test method 100 and its various steps.
[0044] In some embodiments, some or all units or modules of the controller 230 may be located inside the lidar, or some or all units or modules of the controller 230 may be located outside the lidar. Regarding the various modules / units included in the test system described in the above embodiments, they may be software modules / units, hardware modules / units, or a combination of both.
[0045] In some embodiments, the controller 230 may include control circuitry, a central processing unit (CPU), a micro control unit (MCU), a digital signal processor (DSP), other general-purpose processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and other components and circuits.
[0046] The following section, using the test system 200 and two rangefinders as examples, details each step of the test method 100.
[0047] In some embodiments, in step S110, the controller 230 can determine the ranging value based on the points in the lidar point cloud. Figure 3 A partial schematic diagram of an exemplary test system consistent with some embodiments of this disclosure is shown. Figure 3As shown, the target board 210 is located within the field of view of the lidar 300. The lidar 300 scans the field of view and can generate a point cloud. The lidar 300 includes a transmitter 310, a receiver 320, and a processor 330. The transmitter 310 can emit a probe beam L. The receiver 320 can receive the echo E reflected from the probe beam L on the target board 210 and generate an electrical signal. The processor 330 is coupled to the receiver 320 and can generate a point cloud based on the electrical signal. The controller 230 is communicatively connected to the processor 330 and can acquire the point cloud collected by the lidar from the processor 330. The point cloud includes one or more points corresponding to the target board 210. These one or more points include the distance information of the target board 210 measured by the lidar 300. The controller 230 can determine a ranging value dmeasure based on one or more points in the lidar point cloud. The ranging value dmeasure is the distance between the lidar 300 and the target board 210 as measured by the lidar 300. The controller 230 can select one or more specific points from a frame of point cloud from the lidar and use the distance information contained in these one or more points as the ranging value dmeasure.
[0048] In some embodiments, transmitter 310 may include one or more lasers (not shown). The lasers may include laser emitting circuitry, vertical-cavity surface-emitting lasers (VCSELs), edge-emitting lasers (EELs), distributed feedback lasers (DFBs), fiber lasers, or similar devices. Multiple lasers may be arranged in a one-dimensional or two-dimensional array.
[0049] In some embodiments, receiver 320 may include one or more detectors (not shown). Detectors may include photodetector circuitry, single-photon avalanche diodes (SPADs), avalanche photodiodes (APDs), silicon photomultipliers (SiPMs), or similar devices. Multiple detectors may be arranged in a one-dimensional or two-dimensional array.
[0050] In some embodiments, the processor 330 may include processing circuitry, CPU, MCU, DSP, other general-purpose processors, ASIC, FPGA, CPLD or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and other components and circuits.
[0051] It should be noted that, Figure 3The controller 230 shown is located outside the lidar 300, but this disclosure is not limited thereto. Some or all of the units or modules of the controller 230 may be located inside the lidar, or some or all of the units or modules of the controller may be located outside the lidar, all of which are within the protection scope of this disclosure.
[0052] In some embodiments, a lidar includes detection channels. The point cloud includes points corresponding to the detection channels. Lasers and detectors can constitute one or more detection channels of the lidar. A detection channel can include one or more lasers. A detection channel can include one or more detectors. The echo generated by the detection beam emitted by the laser in a detection channel can be received by the detector in that detection channel. The processor can generate points corresponding to a detection channel based on the electrical signals generated by the echo received by the detector in that detection channel. A detection channel can correspond to one or more points. A point in the point cloud can include information such as ranging values and reflectivity values.
[0053] In some embodiments, in step S110, the controller 230 can determine the ranging value of the point corresponding to the detection channel based on the points in the lidar point cloud. The controller 230 can determine the ranging value of one point corresponding to one detection channel. Alternatively, the controller 230 can determine the ranging values of multiple points corresponding to one detection channel. Or, the controller 230 can determine the ranging values of one or more points corresponding to multiple detection channels.
[0054] Ideally, after the target board is placed in the preset position, it has a preset positional attitude relative to the lidar, and thus a preset pose. Optionally, the preset pose can be that the target board is perpendicular to the ground and facing the lidar, with the normal direction of the target board parallel to the positive emission direction of the lidar. Figure 4 This diagram illustrates an exemplary target board whose pose, consistent with some embodiments of the present disclosure, does not deviate from a preset pose. For example, such as... Figure 4 As shown, the preset pose of the target plate 210 can be that the target plate 210 is perpendicular to the ground and directly facing the lidar 300. The laser beam emitted by the lidar 300 in the positive emission direction can be perpendicularly incident on the target plate 210 to form an incident point C. The direction vector (vector T3-C) of the incident point C and the direction vector (vector T3-R) of the perpendicular foot R do not form an angle. The incident point C coincides with the perpendicular foot R. The distance Dc between the lidar 300 and the incident point C, and the perpendicular distance Dr between the lidar 300 and the perpendicular foot R are equal, and are also equal to the first distance D1 and the second distance D2.
[0055] In some cases, after the target board is placed in a preset position, its pose may deviate from the preset pose. For example, the normal direction of the target board may form an angle with the positive emission direction of the lidar (e.g., Figure 5 The included angle α is shown to be ≠ 0. Figure 5 This diagram illustrates a deviation between the pose of an exemplary target board consistent with some embodiments of this disclosure and a preset pose. For example... Figure 5 As shown, the laser beam emitted by the lidar 300 in the forward direction forms an angle α (α≠0) between the direction vector of the incident point C (vector T3-C) on the target plate 210 and the direction vector of the perpendicular foot R (vector T3-R). In this case, the true distance between the target plate and the lidar will be affected, thus affecting the accuracy of the lidar distance accuracy test.
[0056] This disclosure can accurately determine the true distance between the target board and the lidar when there is a deviation between the target board's pose and the preset pose, thereby improving the accuracy of measuring the lidar's ranging error.
[0057] In some embodiments, in step S120, the controller 230 determines a distance calibration value based on a first distance from the first measurement point to the target board and a second distance from the second measurement point to the target board. The distance calibration value is the true distance between the lidar and the target board. The true distance value is associated with a point in the point cloud. For example, the point cloud corresponds to multiple points on the target board, and each point has a true distance value (distance calibration value). As mentioned earlier, a point includes ranging information. Based on the ranging value and the distance calibration value of that point, the ranging error of the detection channel acquired by the lidar at that point can be determined. The true distance values of different points can be the same or different, depending on the relative attitude between the target board and the lidar.
[0058] Figure 6 A schematic diagram illustrating an exemplary determination of distance calibration values according to some embodiments consistent with this disclosure is shown. For example... Figure 6As shown, the first rangefinder 220-1 and the second rangefinder 220-2 can be symmetrically arranged on both sides of the lidar 300, located at the first measurement point T1 and the second measurement point T2, respectively. The lidar 300 is located at the third measurement point T3. The light emission directions of the first rangefinder 220-1 and the second rangefinder 220-2 are parallel to the positive emission direction of the lidar 300. The first rangefinder 220-1 is used to measure the first distance D1 from the first measurement point T1 to the target plate 210. The second rangefinder 220-2 is used to measure the second distance D2 from the second measurement point T2 to the target plate 210. The first rangefinder 220-1 and the second rangefinder 220-2 can be connected to the controller 230 and send the measured first distance D1 and second distance D2 to the controller 230. The controller 230 can determine the distance calibration value dreal based on the first distance D1 and the second distance D2. In this way, the controller 230 can determine the distance calibration value of one or more points corresponding to the detection channel of the lidar test. It is understood that the first rangefinder 220-1 and the second rangefinder 220-2 are not necessarily connected to the controller 230. Alternatively, the controller 230 may receive user input commands via a human machine interface (HMI) (not shown) to obtain a first distance D1 and a second distance D2, and thereby determine a distance calibration value dreal based on the first distance D1 and the second distance D2.
[0059] In some embodiments, determining the distance calibration value includes: determining the perpendicular distance between the lidar and the target board based on a first distance and a second distance; and determining the distance calibration value based on the perpendicular distance and the included angle. This included angle is the angle between the direction vector of the incident point formed by the laser beam emitted by the lidar on the target board and the direction vector of the perpendicular. Figure 2 and Figure 6 As shown, the controller 230 can determine the perpendicular distance Dr between the lidar 300 and the target plate 210 based on the first distance D1 and the second distance D2. Based on the perpendicular distance Dr and the included angle θ, the distance calibration value dreal can be determined. The included angle θ is the angle between the direction vector of point Q (vector T3-Q) and the direction vector of the perpendicular R (vector T3-R). Point Q is an incident point formed on the target plate 210 by a laser beam emitted from any direction in the detection channel of the lidar 300. It should be noted that... Figure 6 An incident point Q is illustrated as an example. It should be understood that the laser beam emitted by the laser of one detection channel of the lidar 300 can form one or more incident points on the target plate, and the laser beams emitted by multiple detection channels can form multiple incident points on the target plate. According to the method of this disclosure, distance calibration values for multiple incident points can be determined.
[0060] This disclosure allows for the measurement of a first distance D1 and a second distance D2 using a rangefinder. Based on the first distance D1 and the second distance D2, the perpendicular distance Dr and the included angle θ are determined. Based on the perpendicular distance Dr and the included angle θ, the distance calibration value dreal of the lidar can be determined. Based on the distance calibration value dreal and the distance measurement value dmeasure, the ranging error derror of the lidar can be accurately determined. This allows for the correction of the ranging error derror when the target board deviates from its preset pose.
[0061] The following section will introduce the specific process for determining the perpendicular distance Dr.
[0062] In some embodiments, determining the perpendicular distance between the lidar and the target plate includes: determining the perpendicular distance based on a first distance, a second distance, and a third distance, wherein the third distance is the distance between the first measurement point and the second measurement point. Figure 5 As shown, the distance between the first measurement point T1 and the second measurement point T2 is the third distance D3. The third distance D3 can be known or determined by measurement. The controller 230 can determine the perpendicular distance Dr between the lidar 300 and the target plate 210 based on the first distance D1, the second distance D2, and the third distance D3.
[0063] The controller 230 can determine the distance Dc between the lidar 300 and point C based on the first distance D1 and the second distance D2. The first measurement point T1 and the second measurement point T2 can be symmetrically set about the third measurement point T3. According to geometric relationships, the distance Dc is half the sum of the first distance D1 and the second distance D2. The controller 230 can determine the distance Dc according to equation (1).
[0064]
[0065] The controller 230 can determine the angle α between the direction vector of point C (vector T3-C) and the direction vector of the perpendicular foot R (vector T3-R) based on the first distance D1, the second distance D2, and the third distance D3. According to the geometric relationship, the controller 230 can determine the angle α according to equation (2).
[0066]
[0067] The controller 230 can determine the perpendicular distance Dr based on the distance Dc and the included angle α. According to the geometric relationship, the controller 230 can determine the perpendicular distance Dr according to equation (3).
[0068]
[0069] When the target plate's pose deviates from the preset pose, the controller determines the distance Dc between the incident point of the laser beam emitted from the lidar in the forward direction and the lidar on the target plate, based on the first distance from the first measurement point to the target plate and the second distance from the second measurement point to the target plate. Then, based on the third distance between the first and second measurement points, the controller determines the angle α between the direction vector of the incident point of the laser beam emitted from the lidar in the forward direction and the direction vector of the perpendicular. Based on the distance Dc and the angle α, the controller determines the perpendicular distance Dr of the lidar to the target plate.
[0070] After determining the perpendicular distance Dr, the controller can accurately determine the distance calibration value dreal of the lidar based on the perpendicular distance Dr and the included angle θ. The specific process of determining the included angle θ is described below.
[0071] In some embodiments, the controller 230 can determine the angle θ between the direction vector (vector T3-Q) of the incident point Q formed on the target plate 210 by the laser beam emitted in any direction from the detection channel of the lidar 300 in the following manner: the direction vector (vector T3-R) of the perpendicular foot R. The controller 230 can determine a first coordinate value A of point Q in the lidar coordinate system; determine a second coordinate value B of the perpendicular foot R in the lidar coordinate system; and determine the angle θ based on the first coordinate value A and the second coordinate value B.
[0072] The first coordinate value A and the second coordinate value B can be polar coordinates. The polar coordinate representation of the second coordinate value B is (azi, ele, droot). Here, azi is the horizontal angle, ele is the pitch angle, and droot is the perpendicular distance. For example, the horizontal angle azi can be determined as angle α after calibration with a rangefinder using the aforementioned method. For example, when the target board is set perpendicular to the ground, the pitch angle ele is 0. When the target board is not set perpendicular to the ground, it can also be determined using a rangefinder or a goniometer.
[0073] Based on the first polar coordinates A, the controller 230 can determine the first unit vector p of the direction vector of point Q. a The controller 230 can determine the second unit vector p of the direction vector with perpendicular foot R based on the second polar coordinate B. b The controller 230 determines the first unit vector p. a Second unit vector p b The included angle θ can be determined.
[0074] First unit vector p a It can be represented by equation (4).
[0075]
[0076] In equation (4), azi a p is the first unit vector a Horizontal angular component; ele a p is the first unit vector a The pitch angle component.
[0077] Second unit vector p b It can be represented by equation (5).
[0078]
[0079] The controller 230, based on the first unit vector p a Second unit vector p b The first unit vector p can be determined. a Second unit vector p b The Euclidean distance d0 is given. Based on the Euclidean distance d0, the included angle θ can be determined.
[0080] The Euclidean distance d0 can be expressed by equation (6).
[0081]
[0082] In equation (6), i is an integer from 1 to 3.
[0083] The controller 230 can determine the radians of the included angle θ based on the Euclidean distance d0. Based on the radians of the included angle θ, the angle angle θ can be determined.
[0084] The angle θ in radians can be expressed by equation (7).
[0085]
[0086] The angle θ can be expressed by equation (8).
[0087] angleθ=degrees(angle_radians)......(8).
[0088] The angle θ can be expressed by equation (9).
[0089]
[0090] In this way, controller 230 can determine the angle angle θ. Controller 230 can determine the distance calibration value dreal based on the perpendicular distance Dr and the angle angle θ. The distance calibration value dreal can be expressed by equation (10).
[0091] dreal=Dr / cos(angleθ)……(10).
[0092] The above example, using point Q, illustrates a method for a controller to determine the distance calibration value of a point in a lidar point cloud. The controller can determine the first coordinate value of a point in the lidar point cloud within the lidar coordinate system and the second coordinate value of its perpendicular point within the lidar coordinate system. Based on the first and second coordinate values, the angle between the point cloud vector and the perpendicular point vector can be determined. Based on the angle and the perpendicular distance, the distance calibration value of that point in the point cloud can be determined. This distance calibration value is the precise distance from the incident point of the probe beam on the target plate to the lidar. Using this method or similar approaches, the controller can determine the distance calibration values for multiple points corresponding to the currently tested detection channel.
[0093] In step S130, the controller 230 can determine the ranging error of the lidar based on the ranging value and the distance calibration value. In some embodiments, determining the ranging error of the lidar includes determining the ranging error of the detection channel. The controller 230 can determine the ranging error of a single detection channel. For example, a single detection channel can correspond to a point. The controller 230 can determine the ranging value and the distance calibration value of that point, and based on the ranging value and the distance calibration value of that point, it can determine the ranging error of that detection channel. For example, a single detection channel can correspond to multiple points. The controller 230 can determine the ranging values and the distance calibration values of the multiple points, and based on the ranging values and the distance calibration values of the multiple points, it can determine the ranging error of that detection channel. Optionally, the lidar includes multiple detection channels, and the controller 230 can determine the ranging errors of multiple detection channels. Optionally, the ranging error can include at least one of ranging accuracy error and ranging precision error.
[0094] For example, a single detection channel can correspond to a single point. The controller 230 can determine the difference between the distance measurement value dmeasure and the distance calibration value dreal at that point, and use this difference as the distance measurement error derror of that detection channel. This distance measurement error derror can be expressed by equation (11). It should be understood that when a single detection channel corresponds to a single point, the distance measurement accuracy error and the distance measurement precision error of the single detection channel are the same, and both can be expressed by equation (11).
[0095] derror=dmeasure﹣dreal……(11).
[0096] For example, a single detection channel can correspond to multiple points. The controller 230 can determine the average and / or root mean square deviation of the differences between the ranging values and distance calibration values for these multiple points; based on this average and / or root mean square deviation, the ranging error of the detection channel is determined. Alternatively, the controller 230 can determine the average and / or root mean square deviation of the ranging errors for the multiple points corresponding to the detection channel; based on this average and / or root mean square deviation, the ranging error of the detection channel is determined. The ranging error includes ranging accuracy error and / or ranging precision error. The controller 230 can determine the average of the ranging errors for multiple points and use this average as the ranging accuracy error of the detection channel. The controller 230 can determine the root mean square deviation of the ranging errors for multiple points and use this root mean square deviation as the ranging precision error of the detection channel.
[0097] The controller 230 can determine the ranging error of multiple detection channels. The controller 230 can determine the ranging accuracy error of each of the multiple detection channels. Alternatively, the controller 230 can determine the ranging precision error of each of the multiple detection channels. Or, the controller 230 can determine both the ranging accuracy error and the ranging precision error of each of the multiple detection channels.
[0098] In some embodiments, the controller 230 can determine the overall ranging error of multiple detection channels. The overall ranging error may include an overall ranging accuracy error and / or an overall ranging precision error. The controller 230 can determine the ranging accuracy error and / or ranging precision error of one detection channel. A detection channel may be assigned a corresponding weight. The controller 230 can determine the overall ranging accuracy error of multiple detection channels based on the individual ranging accuracy errors and weights of each detection channel. Alternatively, the controller 230 can determine the overall ranging precision error of multiple detection channels based on the individual ranging precision errors and weights of each detection channel. Alternatively, the controller 230 can determine the overall ranging accuracy error and overall ranging precision error of multiple detection channels based on their respective overall ranging accuracy errors, overall ranging precision errors, and weights. Different detection channels may have the same weight. In this case, the average of the ranging accuracy errors of multiple detection channels is the overall ranging accuracy error. The average of the ranging precision errors of multiple detection channels is the overall ranging precision error. Alternatively, different detection channels may have different weights. For example, the weight of the detection channel corresponding to the ROI (Region of Interest) of the LiDAR (e.g., the central field of view) can be set higher, while the weight of the detection channel corresponding to the non-ROI (e.g., the edge area) can be set lower, and vice versa. In practical applications, the weight of the detection channel can be set according to requirements.
[0099] In some embodiments, the controller 230 can determine the performance parameters of the lidar based on the ranging error. The performance parameters include at least one of range accuracy or range precision. For example, based on the ranging precision error, the controller 230 can determine the range precision of the lidar; the ranging precision error can be used as the range precision. Based on the ranging precision error of one detection channel, the controller 230 can determine the range precision of that detection channel. Based on the ranging precision errors of multiple detection channels, the controller 230 can determine the individual range precision of each of the multiple detection channels. Based on the combined ranging precision error of the multiple detection channels, the controller 230 can determine the combined range precision of the multiple detection channels.
[0100] For example, the controller 230 can determine the distance accuracy of the lidar based on the ranging accuracy error, which can be used as the distance accuracy. Based on the ranging accuracy error of one detection channel, the controller 230 can determine the distance accuracy of that detection channel. Based on the ranging accuracy errors of multiple detection channels, the controller 230 can determine the distance accuracy of each of the multiple detection channels. Based on the combined ranging accuracy errors of the multiple detection channels, the controller 230 can determine the combined distance accuracy of the multiple detection channels.
[0101] For example, controller 230 can determine the range accuracy and range precision of the lidar based on the ranging accuracy error and ranging precision error. Based on the ranging accuracy error and ranging precision error of a single detection channel, controller 230 can determine the range accuracy and range precision of that single detection channel. Based on the ranging accuracy error and ranging precision error of multiple detection channels, controller 230 can determine the individual range accuracy and range precision of each of the multiple detection channels. Based on the combined ranging accuracy error and combined ranging precision error of the multiple detection channels, controller 230 can determine the combined range accuracy and combined range precision of the multiple detection channels.
[0102] For example, the controller 230 can determine the overall ranging performance of the lidar based on the ranging errors of multiple detection channels. For instance, the controller 230 can determine the overall range accuracy of the lidar based on the ranging accuracy errors of multiple detection channels. The controller 230 can also determine the overall range accuracy of the lidar based on the ranging precision errors of multiple detection channels.
[0103] After determining the performance parameters of the lidar, the controller 230 can determine the lidar's ranging performance based on these parameters. The controller 230 can determine at least one of the lidar's ranging accuracy or ranging precision.
[0104] In some embodiments, the controller 230 can determine the ranging accuracy of the lidar. For example, the controller 230 can compare the ranging accuracy error of a single detection channel with an accuracy error threshold. When the ranging accuracy error is less than or equal to the accuracy error threshold, the controller determines that the ranging accuracy of the single detection channel is high. When the ranging accuracy error is greater than the accuracy error threshold, the controller determines that the ranging accuracy of the single detection channel is low. As another example, the controller 230 can compare the combined ranging accuracy error of multiple detection channels with an accuracy error threshold. When the combined ranging accuracy error is less than or equal to the accuracy error threshold, the controller determines that the combined ranging accuracy of the multiple detection channels is high. When the combined ranging accuracy error is greater than the accuracy error threshold, the controller determines that the combined ranging accuracy of the multiple detection channels is low.
[0105] In some embodiments, the controller 230 can determine the ranging accuracy of the lidar. For example, the controller 230 can compare the ranging accuracy error of a single detection channel with an accuracy error threshold. When the ranging accuracy error is less than or equal to the accuracy error threshold, the controller determines that the distance accuracy of the single detection channel is high. When the ranging accuracy error is greater than the accuracy error threshold, the controller determines that the distance accuracy of the single detection channel is low. As another example, the controller 230 can compare the combined ranging accuracy error of multiple detection channels with an accuracy error threshold. When the combined ranging accuracy error is less than or equal to the accuracy error threshold, the controller determines that the combined distance accuracy of the multiple detection channels is high. When the combined ranging accuracy error is greater than the accuracy error threshold, the controller determines that the combined distance accuracy of the multiple detection channels is low.
[0106] In some embodiments, the controller 230 can use ranging errors to correct and compensate for the ranging performance of the lidar. For example, the controller 230 can use ranging accuracy errors to compensate and correct the ranging values of the lidar's detection channels. This can improve the accuracy and reliability of the lidar ranging results.
[0107] Figure 7 This diagram illustrates the lidar ranging results when the pose of an exemplary target board consistent with some embodiments of the present disclosure does not deviate from a preset pose. Figure 8 This diagram illustrates the ranging results without range measurement performance correction compensation for the lidar when the pose of an exemplary target board, consistent with some embodiments of the present disclosure, deviates from a preset pose. Figure 9 This diagram illustrates the ranging results of correcting and compensating the ranging performance of a lidar using the ranging error determined by this disclosure when the pose of an exemplary target plate, consistent with some embodiments of this disclosure, deviates from a preset pose. Figures 7 to 9 In the diagram, the horizontal axis represents the detection channels of the lidar, the vertical axis represents the measurement distance corresponding to each detection channel, and the dashed line represents the baseline. For example... Figure 7 and Figure 8As shown, when the target board's pose deviates from the preset pose, and when no ranging performance correction compensation is applied to the lidar, the ranging results of each detection channel of the lidar are too high. Figure 7 and Figure 9 As shown, when the target board's pose deviates from the preset pose, and when the ranging error determined in this disclosure is used to correct and compensate for the ranging performance of the lidar, the ranging results of each detection channel of the lidar are basically consistent with the ranging results when the target board's pose does not deviate from the preset pose. The testing method of this disclosure can improve the accuracy of the lidar's ranging error. Using accurate ranging errors, the ranging performance of the lidar can be corrected and compensated, thereby improving the accuracy of the lidar's ranging results.
[0108] The testing method disclosed herein determines the ranging value based on points in the LiDAR point cloud. It then accurately determines the distance calibration value based on a first distance from the first measurement point to the target board and a second distance from the second measurement point to the target board. Finally, it determines the accurate ranging error based on the ranging value and the accurate distance calibration value. This improves the accuracy of measuring the ranging error of the LiDAR. Based on the accurate ranging error, the ranging performance of the LiDAR can be corrected and compensated. This enhances the accuracy and reliability of the LiDAR ranging results. When LiDAR is applied in scenarios such as autonomous driving, it helps the LiDAR accurately perceive the environment, improving the safety performance of autonomous driving.
[0109] The test method disclosed herein can dynamically and accurately determine the distance calibration value between the target board and the lidar when there is a deviation between the pose of the target board and the preset pose, thereby accurately determining the ranging error of the lidar and improving the reliability, flexibility and robustness of lidar accuracy testing.
[0110] The test system disclosed herein can dynamically track the attitude of the target board in real time. When there is a deviation between the pose of the target board and the preset pose, it can automatically and accurately determine the distance calibration value between the target board and the lidar based on the actual pose of the target board, thereby accurately determining the ranging error of the lidar. This helps to achieve accurate, reliable and robust lidar accuracy testing or calibration, and reduces the manpower input and equipment cost input in the testing process.
[0111] In some embodiments, the test system disclosed herein may include a memory. The memory may store information such as the ranging error of the lidar and the measurement distance corresponding to each detection channel. The memory may include random access memory (RAM) or non-volatile memory. Further, the memory may include at least one of the following: phase-change random access memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), read-only memory (ROM), and electrically erasable programmable read-only memory (EEPROM).
[0112] In some embodiments, the test system disclosed herein may include a display screen (not shown). The display screen may be coupled to a controller for visualizing output test results. The display screen may include an LCD (liquid-crystal display), an LED (light emitting diode), an OLED (organic light emitting diode), or the like.
[0113] This disclosure also provides a computer-readable storage medium. The computer-readable storage medium includes computer-executable instructions stored thereon, which, when executed by a processor, perform the test method 100 as described above.
[0114] In some embodiments, the processor may include components or circuits such as processing circuits, CPU, MCU, DSP, other general-purpose processors, ASIC, FPGA, CPLD or other programmable logic devices, discrete gate or transistor logic devices, and discrete hardware components.
[0115] This disclosure can take the form of a computer program product implemented on one or more storage media containing program code. Computer storage media include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to: PRAM, SRAM, DRAM, other types of RAM, ROM, EEPROM, flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital video disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.
[0116] It should be noted that this specification provides method operation steps as shown in the embodiments or diagrams, but based on conventional or non-inventive labor, more or fewer operation steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many steps and does not represent the only execution order. In actual system or device products, the methods shown in the embodiments or flowcharts can be executed sequentially or in parallel.
[0117] It should be noted that although several modules of the lidar / test system have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules described above can be implemented in one module. Conversely, the features and functions of one module described above can be further divided and embodied by multiple modules.
[0118] It should be noted that this disclosure may only include Figure 1-9 Any one or more features of any one or more embodiments. In other words, not all features shown need to be implemented simultaneously in the test methods and test systems of this disclosure.
[0119] Finally, it should be noted that the above descriptions are merely some embodiments of this disclosure and are not intended to limit this disclosure. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.
Claims
1. A testing method for lidar, characterized in that, include: The ranging value is determined based on the points in the lidar point cloud; The distance calibration value is determined based on the first distance from the first measurement point to the target board and the second distance from the second measurement point to the target board; and The ranging error of the lidar is determined based on the ranging value and the distance calibration value.
2. The test method according to claim 1, characterized in that, Determining the distance calibration value includes: Based on the first distance and the second distance, determine the perpendicular distance between the laser radar and the target plate; and The distance calibration value is determined based on the perpendicular distance and the included angle, wherein the included angle is the angle between the direction vector of the point and the direction vector of the perpendicular.
3. The test method according to claim 2, characterized in that, Determining the perpendicular distance between the lidar and the target plate includes: The perpendicular distance is determined based on the first distance, the second distance, and the third distance, wherein the third distance is the distance between the first measurement point and the second measurement point.
4. The test method according to claim 2, characterized in that, Also includes: Determining the included angle includes: Determine the first coordinate value of the point in the lidar coordinate system; Determine the second coordinate value of the perpendicular foot in the lidar coordinate system; and The included angle is determined based on the first coordinate value and the second coordinate value.
5. The test method according to claim 1, characterized in that, The lidar includes a detection channel, the point cloud includes points corresponding to the detection channel, and determining the ranging error of the lidar includes: Determine the ranging error of the detection channel.
6. The test method according to claim 5, characterized in that, The point cloud includes multiple points corresponding to the detection channel, and the ranging error for determining the detection channel includes: Determine the average and / or root mean square error of the differences between the ranging values and distance calibration values of the plurality of points corresponding to the detection channel; and The ranging error of the detection channel is determined based on the average value and / or the root mean square deviation.
7. The test method according to claim 6, characterized in that, The lidar includes multiple detection channels, and determining the ranging error of the detection channels includes determining the ranging error of the multiple detection channels.
8. The test method according to any one of claims 1-7, characterized in that, Also includes: Based on the ranging error, the performance parameters of the lidar are determined, and the performance parameters include at least one of distance accuracy or distance precision.
9. The test method according to any one of claims 1-7, characterized in that, Also includes: The first distance is measured by a first rangefinder whose light emission direction is parallel to the positive emission direction of the lidar. and The second distance is measured by a second rangefinder whose light emission direction is parallel to the positive emission direction of the lidar.
10. The test method according to claim 9, characterized in that, The first rangefinder and the second rangefinder are symmetrically arranged on both sides of the lidar.
11. A testing system for lidar, characterized in that, include: The target board is located in the light emission direction of the lidar; A rangefinder is mounted on the side of the lidar, and The controller is configured to perform the test method as described in any one of claims 1-10.
12. A computer-readable storage medium, characterized in that, It includes computer-executable instructions stored thereon, which, when executed by a processor, implement the test method as described in any one of claims 1-10.