Laser radar calibration method and device, electronic equipment and storage medium

Abstract

The invention provides a laser radar calibration method, a laser radar calibration device, electronic equipment and a storage medium. Acquiring a first point cloud when the vehicle runs, and performing data fitting to determine a correction difference value of a course angle of the to-be-calibrated laser radar and a first translation amount of a coordinate system y axis of the to-be-calibrated laser radar relative to a preset whole vehicle coordinate system y axis; when it is detected that a second calibration device is located in the recognition range of the to-be-calibrated laser radar, obtaining a second point cloud when the vehicle runs, and performing data fitting to determine a second translation amount of the x axis of the coordinate system of the to-be-calibrated laser radar relative to the x axis of the preset whole vehicle coordinate system, and calibrating the to-be-calibrated laser radar based on the correction difference value, the first translation amount and the second translation amount. The to-be-calibrated laser radar is calibrated in a low-cost and fast mode, the positioning accuracy of the automatic driving vehicle is improved, and the obstacle missing report and false report frequency in the vehicle driving process is reduced.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and in particular to a laser radar calibration method, device, electronic equipment and storage medium. Background Art

[0002] LiDAR is an important environmental perception sensor on autonomous vehicles and is widely used for object detection and ranging. The number of LiDARs installed on autonomous vehicles ranges from single to multiple. Before use, the installation position of the LiDAR needs to be calibrated, that is, all LiDAR point cloud coordinates are converted to the same selected coordinate system.

[0003] Currently, a common calibration method is to use a special calibration plate covered with calibration points with known geometric features. The calibration plate is scanned by the lidar, and then a specific algorithm is used to analyze the results of the lidar scan and the geometric features of the calibration plate to determine the parameters of the lidar. However, this method requires the use of a special calibration plate, which will increase additional costs and operational complexity, and has high environmental requirements. It needs to be operated in a controlled indoor environment to ensure the accuracy of the calibration results. At the same time, it is also difficult to accurately obtain the actual x-axis and y-axis translation of the lidar relative to the vehicle coordinate system, resulting in deviations in the registration of the point clouds of each lidar in the x-axis and y-axis directions. Therefore, how to accurately obtain the actual x-axis and y-axis translation of the lidar relative to the vehicle coordinate system and calibrate the lidar is a problem that needs to be solved urgently. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a laser radar calibration method, device, electronic device and storage medium to solve the problem that the installation position of the vehicle-mounted radar is difficult to calibrate.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] The first aspect of the present invention discloses a laser radar calibration method, which is applied to a vehicle controller in a straight-moving vehicle, wherein the laser radar to be calibrated is installed at the front position of the vehicle and the positive direction of a coordinate axis in the coordinate system of the laser radar to be calibrated is consistent with the straight-moving direction of the vehicle; a first calibration device in the form of a continuous flat strip is placed along a straight road, and the first calibration device is parallel to the driving direction of the vehicle; a second calibration device in the form of a continuous flat strip is placed along the straight road, and the second calibration device is perpendicular to the driving direction of the vehicle. The method comprises:

[0007] When it is detected that the first calibration device is located within the recognition range of the laser radar to be calibrated, obtaining a first point cloud when the vehicle is traveling in a straight line;

[0008] Performing data fitting based on the first point cloud to obtain slopes and first intercepts of all fitting straight lines corresponding to the first point cloud;

[0009] Calculate the correction difference of the heading angle of the laser radar to be calibrated according to the arc tangent values ​​of all slopes, where the heading angle refers to the angle between the positive direction of the x-axis of the coordinate system of the laser radar to be calibrated and the positive direction of the x-axis of the preset vehicle coordinate system;

[0010] Calculate the average value of all first intercepts to obtain a first translation of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system;

[0011] When it is detected that the second calibration device is located within the recognition range of the laser radar to be calibrated, obtaining a second point cloud when the vehicle is traveling in a straight line;

[0012] Performing data fitting based on the second point cloud to obtain second intercepts of all fitting lines corresponding to the second point cloud;

[0013] Calculate the average value of all second intercepts to obtain a second translation amount of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system;

[0014] The laser radar to be calibrated is calibrated based on the correction difference of the heading angle, the first translation and the second translation.

[0015] Preferably, performing data fitting based on the first point cloud to obtain the slopes and first intercepts of all fitting lines corresponding to the first point cloud includes:

[0016] Filtering out a target point cloud located within the recognition range of the laser radar to be calibrated from the first point cloud;

[0017] Performing plane fitting on all point clouds in the target point cloud to obtain a fitting plane model;

[0018] Determining the interior points of the fitting plane model as the point cloud to be fitted;

[0019] A straight line fitting is performed for each frame of the point cloud to be fitted, and the slopes and first intercepts of all the fitted straight lines are obtained.

[0020] Preferably, the calculation of the correction difference of the heading angle of the laser radar to be calibrated according to the arc tangent values ​​of all slopes includes:

[0021] Calculate the average of the inverse tangents of all slopes;

[0022] For each inverse tangent value of the slope, calculating the difference between the inverse tangent value and the average value;

[0023] When the difference is greater than a preset threshold, the arc tangent value of the slope corresponding to the difference is eliminated;

[0024] When the difference is not greater than the preset threshold, marking the inverse tangent value of the slope corresponding to the difference as a target inverse tangent value;

[0025] Calculate the average of all target arc tangent values ​​to get the corrected difference in heading angle.

[0026] Preferably, the method further comprises:

[0027] When a new laser radar to be calibrated is detected, a target translation amount between a coordinate system of the new laser radar to be calibrated and a coordinate system of the laser radar that has been calibrated is calculated according to installation information, wherein the installation information is installation detailed information when each laser radar is installed on the vehicle;

[0028] Calculate the translation between the coordinate system of the laser radar that has been calibrated and the coordinate system of the whole vehicle and the target translation to obtain the calibration translation between the coordinate system of the new laser radar to be calibrated and the coordinate system of the whole vehicle;

[0029] The new laser radar to be calibrated is calibrated based on the calibration translation.

[0030] The second aspect of the present invention discloses a laser radar calibration device, which is applied to a vehicle controller in a straight-moving vehicle, wherein the laser radar to be calibrated is installed at the front position of the vehicle and the positive direction of a coordinate axis in the coordinate system of the laser radar to be calibrated is consistent with the straight-moving direction of the vehicle; a first calibration device in the form of a continuous flat strip is placed along a straight road, and the first calibration device is parallel to the driving direction of the vehicle; a second calibration device in the form of a continuous flat strip is placed along a straight road, and the second calibration device is perpendicular to the driving direction of the vehicle, and the device comprises:

[0031] A first acquisition unit, configured to acquire a first point cloud when the vehicle is traveling in a straight line when it is detected that the first calibration device is located within the recognition range of the laser radar to be calibrated;

[0032] a first fitting unit, configured to perform data fitting based on the first point cloud to obtain slopes and first intercepts of all fitting straight lines corresponding to the first point cloud;

[0033] A first calculation unit is used to calculate the correction difference of the heading angle of the laser radar to be calibrated according to the arc tangent values ​​of all slopes, where the heading angle refers to the angle between the positive direction of the x-axis of the coordinate system of the laser radar to be calibrated and the positive direction of the x-axis of the preset vehicle coordinate system;

[0034] A second calculation unit is used to calculate the average value of all the first intercepts to obtain a first translation amount of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system;

[0035] A second acquisition unit is used to acquire a second point cloud when the vehicle is traveling in a straight line when it is detected that the second calibration device is located within the recognition range of the laser radar to be calibrated;

[0036] A second fitting unit, configured to perform data fitting based on the second point cloud to obtain second intercepts of all fitting lines corresponding to the second point cloud;

[0037] A third calculation unit is used to calculate the average value of all the second intercepts to obtain a second translation amount of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system;

[0038] The first calibration unit is used to calibrate the laser radar to be calibrated based on the correction difference of the heading angle, the first translation and the second translation.

[0039] Preferably, the first fitting unit includes:

[0040] A screening module, used to screen out target point clouds within the recognition range of the laser radar to be calibrated from the first point cloud;

[0041] A plane fitting module, used for performing plane fitting on all point clouds in the target point cloud to obtain a fitting plane model;

[0042] A determination module, used for determining the inner points of the fitting plane model as the point cloud to be fitted;

[0043] The straight line fitting module is used to perform straight line fitting on each frame of the point cloud to be fitted, and obtain the slope and the first intercept of all fitted straight lines.

[0044] Preferably, the first computing unit comprises:

[0045] A first calculation module is used to calculate the average value of the arc tangent values ​​of all slopes;

[0046] A second calculation module, configured to calculate, for each inverse tangent value of the slope, a difference between the inverse tangent value and the average value;

[0047] A removal module, configured to remove the arc tangent value of the slope corresponding to the difference when the difference is greater than a preset threshold;

[0048] A marking module, configured to mark the inverse tangent value of the slope corresponding to the difference as a target inverse tangent value when the difference is not greater than the preset threshold;

[0049] The third calculation module is used to calculate the average value of all target arc tangent values ​​to obtain the correction difference of the heading angle.

[0050] Preferably, the device further comprises:

[0051] a fourth calculation unit, configured to calculate, when a new laser radar to be calibrated is detected, a target translation amount between a coordinate system of the new laser radar to be calibrated and a coordinate system of the laser radar that has been calibrated according to installation information, wherein the installation information is installation detailed information when each laser radar is installed on the vehicle;

[0052] a fifth calculation unit, configured to calculate, according to the translation between the coordinate system of the calibrated laser radar and the coordinate system of the vehicle and the target translation, to obtain a calibration translation between the coordinate system of the new laser radar to be calibrated and the coordinate system of the vehicle;

[0053] The second calibration unit is used to calibrate the new laser radar to be calibrated based on the calibration translation.

[0054] A third aspect of the present invention discloses an electronic device, comprising: a memory and a processor;

[0055] Wherein, the memory is used to store programs;

[0056] The processor is used to execute the program, and when the program is executed, it is specifically used to implement the laser radar calibration method disclosed in the first aspect of the present invention.

[0057] The fourth aspect of the present invention discloses a computer storage medium for storing a computer program. When the computer program is executed, it is used to implement the laser radar calibration method disclosed in the first aspect of the present invention.

[0058] Based on the laser radar calibration method, device, electronic device and storage medium provided by the above embodiment of the present invention, when it is detected that the first calibration device is located within the recognition range of the laser radar to be calibrated, the first point cloud when the vehicle is driving is obtained and data fitting is performed to determine the correction difference of the heading angle of the laser radar to be calibrated and the first translation of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system; when it is detected that the second calibration device is located within the recognition range of the laser radar to be calibrated, the second point cloud when the vehicle is driving is obtained and data fitting is performed to determine the second translation of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system, and the laser radar to be calibrated is calibrated based on the correction difference of the heading angle, the first translation and the second translation. Combined with the first calibration device and the second calibration device, the translation of the laser radar to be calibrated relative to the x-axis and y-axis of the preset vehicle coordinate system is calculated, and the laser radar to be calibrated is calibrated in a low-cost and fast manner, which effectively improves the positioning accuracy of the autonomous driving vehicle and reduces the frequency of missed and false alarms of obstacles during vehicle driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0060] Figure 1 A schematic diagram of a layout scenario of a vehicle and a calibration device provided in an embodiment of the present invention;

[0061] Figure 2 A flowchart of a laser radar calibration method provided by an embodiment of the present invention;

[0062] Figure 3 A method flow for calculating the slope and the first intercept provided by an embodiment of the present invention;

[0063] Figure 4 A structural block diagram of a laser radar calibration device provided by an embodiment of the present invention;

[0064] Figure 5 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0067] As can be seen from the background technology, the current calibration method is difficult to accurately obtain the actual x-axis and y-axis translation of the lidar relative to the vehicle coordinate system, resulting in deviations in the alignment of the point clouds of each lidar in the x-axis and y-axis directions.

[0068] Therefore, the embodiment of the present invention provides a laser radar calibration method, device, electronic device and storage medium. When it is detected that the first calibration device is located within the recognition range of the laser radar to be calibrated, the first point cloud when the vehicle is driving is obtained and data fitting is performed to determine the correction difference of the heading angle of the laser radar to be calibrated and the first translation of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system; when it is detected that the second calibration device is located within the recognition range of the laser radar to be calibrated, the second point cloud when the vehicle is driving is obtained and data fitting is performed to determine the second translation of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system, and the laser radar to be calibrated is calibrated based on the correction difference of the heading angle, the first translation and the second translation. The laser radar to be calibrated is calibrated in a low-cost and fast way, which effectively improves the positioning accuracy of the autonomous driving vehicle and reduces the frequency of missed and false alarms of obstacles during vehicle driving.

[0069] See also Figure 1, shows a schematic diagram of the arrangement scenario of a vehicle and a calibration device provided in an embodiment of the present invention, wherein at least one laser radar is arranged on the vehicle, and the laser radar (for example, a first laser radar and a second laser radar) is arranged at the front position of the vehicle, wherein the positive direction of a coordinate axis in the coordinate system of the laser radar is consistent with the direction in which the vehicle travels in a straight line. The first calibration device (calibration device A) is in the shape of a continuous flat long strip, has no protruding parts, and is placed along a straight road. The first calibration device (calibration device A) is parallel to the driving direction of the vehicle. The second calibration device (calibration device B) is in the shape of a continuous flat long strip, has no protruding parts, and is placed along a straight road. The second calibration device (calibration device B) is perpendicular to the driving direction of the vehicle. In the specific laser radar calibration process, the vehicle travels in a straight line along the first calibration device (calibration device A) to the second calibration device (calibration device B).

[0070] It should be noted that a second calibration device (calibration device B) is placed perpendicular to the first calibration device (calibration device A) along the rear end of the first calibration device (calibration device A), so as to ensure that when the vehicle travels in a straight line along the first calibration device (calibration device A) to the rear end of the first calibration device (calibration device A), the laser radar can detect the second calibration device (calibration device B) perpendicular to the vehicle body.

[0071] It can be understood that in the embodiment of the present invention, all coordinate systems are right-handed coordinate systems, the forward axis is recorded as the positive direction of the x-axis, the lateral left is recorded as the positive direction of the y-axis, and the longitudinal direction is recorded as the positive direction of the z-axis.

[0072] In a specific application, the height of the first calibration device (calibration device A) is at least higher than 20 cm and the length is at least longer than 100 m, for example, a common single-layer guardrail beside a road, the height of the single-layer guardrail is about 1 m, the length is more than 50 m, and it is placed along a straight one-way road. When the vehicle is traveling in a straight line, the vehicle body and the first calibration device (calibration device A) are parallel to each other, the laser radar on the vehicle can identify the first calibration device (calibration device A), and there is no obstruction between the vehicle body and the first calibration device (calibration device A), for example, the parallel distance between the first calibration device (calibration device A) and the vehicle body is 1 m to 1.5 m.

[0073] It should be noted that the height of the second calibration device (calibration device B) is at least higher than 20 cm and the length is at least longer than 10 m, for example: a single-layer guardrail beside the road, a curb or a flat wall.

[0074] See also Figure 2 , shows a flow chart of a laser radar calibration method provided by an embodiment of the present invention, the method is applied to a vehicle controller in a straight-line vehicle, and the following is combined with the above Figure 1 The schematic diagram of the arrangement scenario of the vehicle and the calibration device is shown to explain the calibration method.

[0075] Step S201: When it is detected that the first calibration device is located within the recognition range of the laser radar to be calibrated, a first point cloud when the vehicle is traveling in a straight line is obtained.

[0076] It should be noted that the recognition range of the laser radar to be calibrated, ie, the region of interest (ROI) of the point cloud, is set in advance according to the horizontal distance between the laser radar to be calibrated and the first calibration device.

[0077] For example: set the recognition range of the laser radar to be calibrated to x(1, 1.5), y(-10, 10); then the range of 1m to 1.5m in the x-axis direction and -10m to 10m in the y-axis direction of the laser radar to be calibrated is the recognition range of the laser radar to be calibrated.

[0078] In the process of specifically implementing step S201, when it is detected that the number of point clouds within the recognition range of the laser radar to be calibrated exceeds the preset point cloud number threshold, it indicates that the first calibration device (calibration device A) is located within the recognition range (point cloud area of ​​interest) of the laser radar to be calibrated. At this time, the first point cloud is obtained when the vehicle is driving in a straight line along the first calibration device (calibration device A).

[0079] It should be noted that the first point cloud includes many frame point clouds generated when the vehicle is driving in a straight line, and each frame point cloud includes multiple point clouds.

[0080] Step S202: performing data fitting based on the first point cloud to obtain the slopes and first intercepts of all fitting lines corresponding to the first point cloud.

[0081] In the process of specifically implementing step S202, the first point cloud is preprocessed, a plane fitting is performed based on the preprocessed first point cloud to obtain a fitting plane model, a point cloud to be fitted is determined based on the fitting plane model, a straight line fitting is performed on the point cloud to be fitted, and the slopes and first intercepts of all fitting straight lines are obtained.

[0082] Optionally, in another embodiment of the present application, the specific implementation of step S202 is as follows: Figure 3 As shown, the following steps are included:

[0083] Step S301: Filter out target point clouds within the recognition range of the laser radar to be calibrated from the first point cloud.

[0084] In the process of implementing step S301, the point clouds in the first point cloud that are outside the recognition range of the laser radar to be calibrated (the point cloud area of ​​interest) are filtered out, and the target point clouds that are within the recognition range of the laser radar to be calibrated (the point cloud area of ​​interest) are screened out from the first point cloud.

[0085] Step S302: performing plane fitting on all point clouds in the target point cloud to obtain a fitting plane model.

[0086] In the process of implementing step S302, plane fitting is performed on all point clouds in the target point cloud, for example, a RANSAC algorithm is used to perform plane fitting on all point clouds in the target point cloud to obtain a fitting plane model.

[0087] It can be understood that the basic idea of ​​the RANSAC algorithm is to establish a candidate plane model by randomly selecting sample points (i.e., any point cloud in the target point cloud), and then determine whether other data points are consistent with the model by calculating the distance from the plane. According to the set threshold, the data points consistent with the plane are marked as inliers, and the data points inconsistent with the plane are marked as outliers. Then, this process is repeated many times, and the model with the largest number of inliers is selected as the final fitting result. In the embodiment of the present invention, this model is recorded as the fitting plane model.

[0088] Step S303: determining the inner points of the fitted plane model as the point cloud to be fitted.

[0089] In the specific implementation of step S303 , the inner points in the fitting plane model obtained by plane fitting using the RANSAC algorithm are determined as the point cloud to be fitted.

[0090] Step S304: performing straight line fitting for each frame of the point cloud to be fitted, and obtaining the slopes and first intercepts of all fitted straight lines.

[0091] In the specific process of implementing step S304, a least square method is used to perform straight line fitting on each frame of the point cloud to be fitted, and the slopes and first intercepts of all fitted straight lines are obtained.

[0092] For example: the point cloud to be fitted contains many frame point clouds, each frame point cloud contains n point clouds, and the coordinates of the point cloud are (x i ,y i ), the fitted straight line obtained after straight line fitting is recorded as x=k*y+b, and the least squares method is used to perform straight line fitting on each frame of the point cloud to be fitted, and the process of obtaining the slope k and the first intercept b of all the fitted straight lines is shown in the following formulas (1) to (7).

[0093]

[0094] The sum of the x-coordinate values ​​of all the point cloud coordinates in a frame is calculated by formula (1); the sum of the y-coordinate values ​​of all the point cloud coordinates in a frame is calculated by formula (2).

[0095]

[0096] theta=n*sumXX-sumX*sumX(5)

[0097] The sum of the products of the x-coordinate values ​​and the y-coordinate values ​​of all the point cloud coordinates in a frame is calculated by formula (3); the sum of the products of the x-coordinate values ​​and the x-coordinate values ​​of all the point cloud coordinates in a frame is calculated by formula (4).

[0098] k=(n*sumXY-sumX*sumY) / theta(6)

[0099] b=(sumXX*sumY-sumXY*sumX) / theta (7)

[0100] Refer to formula (6), and calculate the slope k of all fitted straight lines in a frame by the least squares method; refer to formula (7), and calculate the first intercept b of all fitted straight lines in a frame by the least squares method.

[0101] Step S203: Calculate the correction difference of the heading angle of the laser radar to be calibrated according to the arc tangent values ​​of all slopes.

[0102] It should be noted that the heading angle refers to the angle between the positive direction of the x-axis of the coordinate system of the laser radar to be calibrated and the positive direction of the x-axis of the preset vehicle coordinate system.

[0103] In the specific implementation of step S203, the correction difference of the heading angle of the laser radar to be calibrated is obtained by calculating the arc tangent value of the slope of all the fitting lines.

[0104] In some specific embodiments, in order to improve the accuracy of the correction difference of the heading angle, the average value of the inverse tangent values ​​of all slopes is calculated; for each inverse tangent value of the slope, the difference between the inverse tangent value and the average value is calculated; when the difference is greater than a preset threshold, the inverse tangent value of the slope corresponding to the difference is eliminated; when the difference is not greater than the preset threshold, the inverse tangent value of the slope corresponding to the difference is marked as the target inverse tangent value; the average value of all target inverse tangent values ​​is calculated to obtain the correction difference of the heading angle.

[0105] It can be understood that, according to the relationship between the arctangent values ​​of each slope and the average value of the arctangent values ​​of all slopes, the arctangent values ​​with a larger difference from the average value are proposed, which reduces the influence of outliers on the final average value and improves the accuracy of the correction difference of the heading angle.

[0106] Step S204: Calculate the average value of all first intercepts to obtain the first translation of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system.

[0107] In some specific embodiments, similar to the principle of improving the accuracy of the correction difference of the heading angle in the above-mentioned step S203, in order to improve the accuracy of the first translation, the average value of all the first intercepts is first calculated, and the difference between each first intercept and the average value is compared to see whether it is greater than a preset threshold value. When the difference between any first intercept and the average value is greater than the preset threshold value, the current first intercept is eliminated, and the first intercept whose difference with the average value is not greater than the preset threshold value is retained and recorded as the target first intercept. The average value is calculated based on all the target first intercepts to obtain a higher-precision first translation of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system.

[0108] Step S205: When it is detected that the second calibration device is within the recognition range of the laser radar to be calibrated, a second point cloud is obtained when the vehicle is traveling in a straight line.

[0109] In the process of implementing step S205, when it is detected that the number of point clouds within the recognition range of the laser radar to be calibrated exceeds the preset point cloud number threshold, it indicates that the second calibration device (calibration device B) is located within the recognition range of the laser radar to be calibrated (point cloud area of ​​interest). At this time, the second point cloud is obtained when the vehicle is driving in a straight line along the second calibration device (calibration device B).

[0110] It should be noted that the second point cloud includes many frame point clouds generated when the vehicle is driving in a straight line, and each frame point cloud includes multiple point clouds.

[0111] Step S206: performing data fitting based on the second point cloud to obtain second intercepts of all fitting lines corresponding to the second point cloud.

[0112] In the process of specifically implementing step S206, the point clouds in the second point cloud that are outside the recognition range of the laser radar to be calibrated (the point cloud area of ​​interest) are filtered out, and the point clouds within the recognition range of the laser radar to be calibrated (the point cloud area of ​​interest) are screened out from the second point cloud. Plane fitting is performed based on the screened point clouds to obtain a fitting plane model corresponding to the second point cloud. A new point cloud to be fitted is determined based on the fitting plane model corresponding to the second point cloud. A straight line fitting is performed on the new point cloud to be fitted to obtain the second intercepts of the fitting straight lines of all new point clouds to be fitted.

[0113] It should be noted that the specific implementation method of calculating the second intercept is similar to the specific implementation method of step S202, that is, the second intercept is calculated by formula (1) to formula (5) and formula (7), and the specific implementation process will not be repeated here.

[0114] Step S207: Calculate the average value of all second intercepts to obtain the second translation of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system.

[0115] It can be understood that the X-axis in the coordinate system of the laser radar to be calibrated is calibrated by calculating the distance between the laser radar to be calibrated and the second calibration device (calibration device B).

[0116] In combination with the method of improving accuracy proposed in the above steps S203 and S204, in the process of implementing step S207, the average value of all second intercepts is calculated, and the difference between each second intercept and the average value is compared to see whether it is greater than a preset threshold value. When the difference between any second intercept and the average value is greater than the preset threshold value, the current second intercept is eliminated, and the second intercept whose difference with the average value is not greater than the preset threshold value is retained and recorded as the target second intercept. The average value is calculated based on all target second intercepts to obtain a second translation amount of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system with higher accuracy.

[0117] Step S208: Calibrate the laser radar to be calibrated based on the correction difference of the heading angle, the first translation and the second translation.

[0118] In the specific implementation of step S208, the original heading angle parameters pre-set in the vehicle and the corrected heading angle difference are used for calculation to obtain new heading angle parameters of the vehicle, and the laser radar to be calibrated is calibrated based on the first translation and the second translation of the new heading angle parameters.

[0119] In some specific embodiments, when there are multiple laser radars to be calibrated in a vehicle, after the calibration of the first laser radar to be calibrated is completed, a new laser radar to be calibrated can be calibrated according to the laser radar that has been calibrated.

[0120] That is to say, when a new laser radar to be calibrated is detected, the target translation between the coordinate system of the new laser radar to be calibrated and the coordinate system of the laser radar that has been calibrated is calculated according to the installation information, wherein the installation information is the installation details when each laser radar is installed on the vehicle; the calibration translation between the coordinate system of the laser radar that has been calibrated and the coordinate system of the whole vehicle is calculated according to the translation and target translation, and the new laser radar to be calibrated is calibrated based on the calibration translation.

[0121] In an embodiment of the present invention, when it is detected that the first calibration device is located within the identification range of the laser radar to be calibrated, the first point cloud when the vehicle is traveling is obtained and data fitting is performed to determine the correction difference of the heading angle of the laser radar to be calibrated and the first translation of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system; when it is detected that the second calibration device is located within the identification range of the laser radar to be calibrated, the second point cloud when the vehicle is traveling is obtained and data fitting is performed to determine the second translation of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system, and the laser radar to be calibrated is calibrated based on the correction difference of the heading angle, the first translation and the second translation. The laser radar to be calibrated is calibrated in a low-cost and fast way, which effectively improves the positioning accuracy of the autonomous driving vehicle and reduces the frequency of missed and false alarms of obstacles during vehicle driving.

[0122] Corresponding to the laser radar calibration method provided in the above embodiment of the present invention, see Figure 4 , shows a structural block diagram of a laser radar calibration device provided in an embodiment of the present invention, which is applied to a vehicle controller in a straight-line vehicle, and includes: a first acquisition unit 401, a first fitting unit 402, a first calculation unit 403, a second calculation unit 404, a second acquisition unit 405, a second fitting unit 406, a third calculation unit 407 and a first calibration unit 408.

[0123] The first acquisition unit 401 is used to acquire a first point cloud when the vehicle is traveling in a straight line when it is detected that the first calibration device is located within the recognition range of the laser radar to be calibrated.

[0124] The first fitting unit 402 is used to perform data fitting based on the first point cloud to obtain the slopes and first intercepts of all fitting lines corresponding to the first point cloud.

[0125] The first calculation unit 403 is used to calculate the correction difference of the heading angle of the laser radar to be calibrated according to the arc tangent values ​​of all slopes, and the heading angle refers to the angle between the positive direction of the x-axis of the coordinate system of the laser radar to be calibrated and the positive direction of the x-axis of the preset vehicle coordinate system.

[0126] The second calculation unit 404 is used to calculate the average value of all the first intercepts to obtain the first translation amount of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system.

[0127] The second acquisition unit 405 is used to acquire a second point cloud when the vehicle is traveling in a straight line when it is detected that the second calibration device is located within the recognition range of the laser radar to be calibrated.

[0128] The second fitting unit 406 is used to perform data fitting based on the second point cloud to obtain second intercepts of all fitting lines corresponding to the second point cloud.

[0129] The third calculation unit 407 is used to calculate the average value of all the second intercepts to obtain the second translation amount of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system.

[0130] The first calibration unit 408 is used to calibrate the laser radar to be calibrated based on the correction difference of the heading angle, the first translation amount and the second translation amount.

[0131] In an embodiment of the present invention, when it is detected that the first calibration device is located within the identification range of the laser radar to be calibrated, the first point cloud when the vehicle is traveling is obtained and data fitting is performed to determine the correction difference of the heading angle of the laser radar to be calibrated and the first translation of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system; when it is detected that the second calibration device is located within the identification range of the laser radar to be calibrated, the second point cloud when the vehicle is traveling is obtained and data fitting is performed to determine the second translation of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system, and the laser radar to be calibrated is calibrated based on the correction difference of the heading angle, the first translation and the second translation. The laser radar to be calibrated is calibrated in a low-cost and fast way, which effectively improves the positioning accuracy of the autonomous driving vehicle and reduces the frequency of missed and false alarms of obstacles during vehicle driving.

[0132] Combination Figure 4 As shown in the content, the first fitting unit 402 includes: a screening module, a plane fitting module, a determination module and a straight line fitting module.

[0133] The screening module is used to screen out target point clouds within the recognition range of the laser radar to be calibrated from the first point cloud.

[0134] The plane fitting module is used to perform plane fitting on all point clouds in the target point cloud to obtain a fitting plane model.

[0135] The determination module is used to determine the inner points of the fitted plane model as the point cloud to be fitted.

[0136] The straight line fitting module is used to perform straight line fitting for each frame of the point cloud to be fitted, and obtain the slope and the first intercept of all fitted straight lines.

[0137] Combination Figure 4 As shown in the content, the first calculation unit 403 includes: a first calculation module, a second calculation module, a removal module, a marking module and a third calculation module.

[0138] The first calculation module is used to calculate the average value of the arc tangent values ​​of all slopes.

[0139] The second calculation module is used to calculate the difference between the arctangent value and the average value for each arctangent value of the slope.

[0140] The elimination module is used to eliminate the arc tangent value of the slope corresponding to the difference when the difference is greater than a preset threshold.

[0141] The marking module is used to mark the arc tangent value of the slope corresponding to the difference as the target arc tangent value when the difference is not greater than a preset threshold.

[0142] The third calculation module is used to calculate the average value of all target arc tangent values ​​to obtain the correction difference of the heading angle.

[0143] Combination Figure 4 As shown in the figure, the calibration device further includes: a fourth calculation unit, a fifth calculation unit and a second calibration unit.

[0144] a fourth calculation unit, configured to calculate, when a new laser radar to be calibrated is detected, a target translation amount between a coordinate system of the new laser radar to be calibrated and a coordinate system of the laser radar that has been calibrated according to installation information, wherein the installation information is installation detailed information when each laser radar is installed on the vehicle;

[0145] A fifth calculation unit is used to calculate, according to the translation amount between the coordinate system of the calibrated laser radar and the coordinate system of the whole vehicle and the target translation amount, to obtain a calibration translation amount between the coordinate system of the new laser radar to be calibrated and the coordinate system of the whole vehicle;

[0146] The second calibration unit is used to calibrate the new laser radar to be calibrated based on the calibration translation.

[0147] Another embodiment of the present application provides an electronic device, such as Figure 5 As shown, it includes: a memory 501 and a processor 502.

[0148] The memory 501 is used to store programs.

[0149] The processor 502 is used to execute the program. When the program is executed, it is specifically used to implement the laser radar calibration method provided in any one of the above embodiments.

[0150] Another embodiment of the present application provides a computer storage medium for storing a computer program. When the computer program is executed, it is used to implement the laser radar calibration method provided in any one of the above embodiments.

[0151] Computer storage media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0152] In summary, the present invention provides a laser radar calibration method, device, electronic device and storage medium, which are combined with a first calibration device and a second calibration device to calculate the translation amount of the laser radar to be calibrated relative to the x-axis and y-axis of a preset vehicle coordinate system, so as to calibrate the laser radar to be calibrated in a low-cost and fast manner, effectively improve the positioning accuracy of the autonomous driving vehicle, and reduce the frequency of obstacle omissions and false alarms during vehicle driving.

[0153] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0154] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0155] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A laser radar calibration method, characterized in that: A vehicle controller applied to a vehicle traveling in a straight line, wherein a laser radar to be calibrated is installed at the front position of the vehicle and the positive direction of a coordinate axis in the coordinate system of the laser radar to be calibrated is consistent with the direction in which the vehicle is traveling in a straight line; a first calibration device in the form of a continuous flat strip is placed along a straight road, and the first calibration device is parallel to the direction in which the vehicle is traveling; a second calibration device in the form of a continuous flat strip is placed along a straight road, and the second calibration device is perpendicular to the direction in which the vehicle is traveling, and the method comprises: When it is detected that the first calibration device is located within the recognition range of the laser radar to be calibrated, obtaining a first point cloud when the vehicle is traveling in a straight line; Performing data fitting based on the first point cloud to obtain slopes and first intercepts of all fitting straight lines corresponding to the first point cloud; Calculate the correction difference of the heading angle of the laser radar to be calibrated according to the arc tangent values ​​of all slopes, where the heading angle refers to the angle between the positive direction of the x-axis of the coordinate system of the laser radar to be calibrated and the positive direction of the x-axis of the preset vehicle coordinate system; Calculate the average value of all first intercepts to obtain a first translation of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system; When it is detected that the second calibration device is located within the recognition range of the laser radar to be calibrated, obtaining a second point cloud when the vehicle is traveling in a straight line; Performing data fitting based on the second point cloud to obtain second intercepts of all fitting straight lines corresponding to the second point cloud; Calculate the average value of all second intercepts to obtain a second translation amount of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system; The laser radar to be calibrated is calibrated based on the correction difference of the heading angle, the first translation and the second translation.

2. The method according to claim 1, characterized in that The performing data fitting based on the first point cloud to obtain the slopes and first intercepts of all fitting lines corresponding to the first point cloud includes: Filtering out a target point cloud located within the recognition range of the laser radar to be calibrated from the first point cloud; Performing plane fitting on all point clouds in the target point cloud to obtain a fitting plane model; Determining the interior points of the fitting plane model as the point cloud to be fitted; A straight line fitting is performed for each frame of the point cloud to be fitted, and the slopes and first intercepts of all the fitted straight lines are obtained.

3. The method according to claim 1, characterized in that The step of calculating the correction difference of the heading angle of the laser radar to be calibrated according to the arc tangent values ​​of all slopes includes: Calculate the average of the inverse tangents of all slopes; For each inverse tangent value of the slope, calculating the difference between the inverse tangent value and the average value; When the difference is greater than a preset threshold, the arc tangent value of the slope corresponding to the difference is eliminated; When the difference is not greater than the preset threshold, marking the inverse tangent value of the slope corresponding to the difference as a target inverse tangent value; Calculate the average of all target arc tangent values ​​to get the corrected difference in heading angle.

4. The method according to claim 1, characterized in that: The method further comprises: When a new laser radar to be calibrated is detected, a target translation amount between a coordinate system of the new laser radar to be calibrated and a coordinate system of the laser radar that has been calibrated is calculated according to installation information, wherein the installation information is installation detailed information when each laser radar is installed on the vehicle; Calculate the translation between the coordinate system of the laser radar that has been calibrated and the coordinate system of the whole vehicle and the target translation to obtain the calibration translation between the coordinate system of the new laser radar to be calibrated and the coordinate system of the whole vehicle; The new laser radar to be calibrated is calibrated based on the calibration translation.

5. A laser radar calibration device, characterized in that: A vehicle controller for a vehicle traveling in a straight line, wherein a laser radar to be calibrated is installed at the front of the vehicle and the positive direction of a coordinate axis in the coordinate system of the laser radar to be calibrated is consistent with the direction in which the vehicle is traveling in a straight line; a first calibration device in the form of a continuous flat strip is placed along a straight road, and the first calibration device is parallel to the direction in which the vehicle is traveling; a second calibration device in the form of a continuous flat strip is placed along a straight road, and the second calibration device is perpendicular to the direction in which the vehicle is traveling, and the device comprises: A first acquisition unit, configured to acquire a first point cloud when the vehicle is traveling in a straight line when it is detected that the first calibration device is located within the recognition range of the laser radar to be calibrated; a first fitting unit, configured to perform data fitting based on the first point cloud to obtain slopes and first intercepts of all fitting straight lines corresponding to the first point cloud; A first calculation unit is used to calculate the correction difference of the heading angle of the laser radar to be calibrated according to the arc tangent values ​​of all slopes, where the heading angle refers to the angle between the positive direction of the x-axis of the coordinate system of the laser radar to be calibrated and the positive direction of the x-axis of the preset vehicle coordinate system; A second calculation unit is used to calculate the average value of all the first intercepts to obtain a first translation amount of the y-axis of the coordinate system of the laser radar to be calibrated relative to the y-axis of the preset vehicle coordinate system; A second acquisition unit is used to acquire a second point cloud when the vehicle is traveling in a straight line when it is detected that the second calibration device is located within the recognition range of the laser radar to be calibrated; A second fitting unit, configured to perform data fitting based on the second point cloud to obtain second intercepts of all fitting lines corresponding to the second point cloud; A third calculation unit is used to calculate the average value of all the second intercepts to obtain a second translation amount of the x-axis of the coordinate system of the laser radar to be calibrated relative to the x-axis of the preset vehicle coordinate system; The first calibration unit is used to calibrate the laser radar to be calibrated based on the correction difference of the heading angle, the first translation and the second translation.

6. The device according to claim 5, characterized in that The first fitting unit comprises: A screening module, used to screen out target point clouds within the recognition range of the laser radar to be calibrated from the first point cloud; A plane fitting module, used for performing plane fitting on all point clouds in the target point cloud to obtain a fitting plane model; A determination module, used for determining the inner points of the fitting plane model as the point cloud to be fitted; The straight line fitting module is used to perform straight line fitting on each frame of the point cloud to be fitted, and obtain the slope and the first intercept of all fitted straight lines.

7. The device according to claim 5, characterized in that The first computing unit comprises: A first calculation module is used to calculate the average value of the arc tangent values ​​of all slopes; A second calculation module, configured to calculate, for each inverse tangent value of the slope, a difference between the inverse tangent value and the average value; A removal module, configured to remove the arc tangent value of the slope corresponding to the difference when the difference is greater than a preset threshold; A marking module, configured to mark the inverse tangent value of the slope corresponding to the difference as a target inverse tangent value when the difference is not greater than the preset threshold; The third calculation module is used to calculate the average value of all target arc tangent values ​​to obtain the correction difference of the heading angle.

8. The device according to claim 5, characterized in that The device also includes: a fourth calculation unit, configured to calculate, when a new laser radar to be calibrated is detected, a target translation amount between a coordinate system of the new laser radar to be calibrated and a coordinate system of the laser radar that has been calibrated according to installation information, wherein the installation information is installation detailed information when each laser radar is installed on the vehicle; a fifth calculation unit, configured to calculate, according to the translation between the coordinate system of the calibrated laser radar and the coordinate system of the vehicle and the target translation, to obtain a calibration translation between the coordinate system of the new laser radar to be calibrated and the coordinate system of the vehicle; The second calibration unit is used to calibrate the new laser radar to be calibrated based on the calibration translation.

9. An electronic device, characterized in that: include: Memory and processor; Wherein, the memory is used to store programs; The processor is used to execute the program, and when the program is executed, it is specifically used to implement the laser radar calibration method as described in any one of claims 1 to 4.

10. A computer storage medium, characterized in that: Used to store a computer program, which, when executed, is used to implement the laser radar calibration method as described in any one of claims 1 to 4.

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