Fine adjustment method and detection system for ranging error of laser radar

Abstract

The invention provides a laser radar ranging error fine tuning method and a detection system. The method comprises the following steps: acquiring distance measurement data of test points in a test area of a calibrated test board at a plurality of preset positions, wherein the distance measurement data is acquired by a laser radar; based on the distance measurement data of all the test points in the test area of each test board, determining a first distance measurement error of the calibration distance of the laser radar corresponding to each test board; and performing polynomial fitting based on the first distance measurement error corresponding to the calibration distance of each test board, and determining a second distance measurement error of the calibration distance of the laser radar corresponding to each test board based on the obtained fitting polynomial. According to the invention, when the ranging errors corresponding to different calibration distances of the laser radar are determined, the ranging errors can be finely adjusted, so that a unified standard is adopted for ranging error detection of environment objects with different gray levels, the product quality can be directly judged according to the detection result, and the detection efficiency is improved. And the production efficiency and the ex-factory qualified rate of mass production of laser radars can be improved.

Description

Technical Field

[0001] The present application relates to the field of laser radar detection technology, and in particular to a technology for fine-tuning laser radar ranging errors. Background Art

[0002] In recent years, with the technological development in surveying and mapping, robot navigation, intelligent driving and other fields, as well as the rapid development of lidar technology, the application of lidar in these fields has become more and more popular.

[0003] In order to ensure the effects of mapping, navigation, route planning, etc., the LiDAR needs to collect stable point cloud data, and having relatively accurate performance parameters is a prerequisite. Therefore, in the production process of LiDAR, each LiDAR needs to be tested for performance parameters (such as ranging range, ranging error, ranging accuracy, ranging temperature drift, etc.) to ensure the quality of each LiDAR shipped. In the existing factory inspection for ranging errors, there is no unified standard for the detection of environmental objects adapted to different grayscales, and thus the product quality cannot be determined based on the test results, which affects the production efficiency of mass-produced LiDARs and also affects the factory pass rate. Summary of the invention

[0004] The purpose of this application is to provide a fine-tuning method and detection system for laser radar ranging errors, so as to at least partially solve the technical problem in the prior art of factory detection of laser radar ranging errors, that there is no unified standard for the detection of environmental objects with different grayscales.

[0005] According to one aspect of the present application, a method for fine-tuning a laser radar ranging error is provided, wherein the method comprises:

[0006] Obtaining ranging data of test points in a test area of ​​a calibrated test board at a plurality of preset positions collected by a laser radar;

[0007] Determine a first ranging error of the laser radar corresponding to the calibrated distance of each test board based on the ranging data of all test points in the test area of ​​each test board;

[0008] Based on the first ranging error corresponding to the calibrated distance of each test plate, a polynomial fitting is performed, and based on the obtained fitting polynomial, the second ranging error of the laser radar corresponding to the calibrated distance of each test plate is determined.

[0009] Optionally, the determining the first ranging error of the laser radar corresponding to the calibrated distance of each test board based on the ranging data of all test points in the test area of ​​each test board includes:

[0010] Determine the average distance of the test board based on the acquired ranging data of all test points in the test area of ​​the same test board, and determine the first ranging error of the laser radar corresponding to the calibrated distance of the test board based on the average distance and the calibrated distance of the test board;

[0011] Traverse each test board and determine the first ranging error of the laser radar corresponding to the calibration distance of each test board.

[0012] Optionally, the determining, based on the obtained fitting polynomial, a second ranging error of the laser radar corresponding to the calibrated distance of each test plate comprises:

[0013] The calibrated distance of each test plate is substituted into the obtained fitting polynomial, and the obtained result is determined as the second ranging error of the laser radar corresponding to the calibrated distance of the test plate.

[0014] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0015] The laser radar is placed in a temperature box where the temperature inside the box is not lower than a first preset temperature threshold for not less than a first preset time threshold, then taken out, placed on a test bench and calibrated;

[0016] Collecting the ranging data of all the test points in the test area of ​​each test board, and determining the fitting distance of each test point in the test area of ​​each test board and the high temperature mode average distance of each test board based on the ranging data of all the test points in the test area of ​​each test board, and determining the high temperature mode ranging error of the laser radar corresponding to the calibrated distance of each test board based on the high temperature mode average distance of each test board;

[0017] Based on the fitted distance of each test point in the test area of ​​each test board and the average distance in the high temperature mode, the high temperature mode ranging accuracy of the laser radar corresponding to the calibrated distance of each test board is determined.

[0018] Optionally, the determining the fitting distance of each test point in the test area of ​​each test board based on the distance measurement data of all test points in the test area of ​​each test board comprises:

[0019] Based on the acquired distance measurement data of all test points in the test area of ​​the same test board, linear fitting is performed to obtain a fitting straight line corresponding to the test board, and based on the fitting straight line corresponding to the test board, a fitting distance of each test point in the test area of ​​the test board is determined;

[0020] Each test board is traversed to determine the fitting distance for each test point in the test area of ​​each test board.

[0021] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0022] The high temperature mode ranging error quality level of the lidar is determined based on the high temperature mode ranging error of the lidar corresponding to the calibrated distance of each test plate.

[0023] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0024] The high temperature mode ranging accuracy quality level of the lidar is determined based on the high temperature mode ranging accuracy of the lidar corresponding to the calibrated distance of each test plate.

[0025] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0026] The laser radar is placed in a temperature box where the temperature inside the box is not higher than a second preset temperature threshold for not less than a second preset time threshold, then taken out, placed on a test bench and calibrated;

[0027] Collecting the ranging data of all the test points in the test area of ​​each test board, and determining the fitting distance of each test point in the test area of ​​each test board and the low temperature mode average distance of each test board based on the ranging data of all the test points in the test area of ​​each test board, and determining the low temperature mode ranging error of the laser radar corresponding to the calibrated distance of each test board based on the low temperature mode average distance of each test board;

[0028] Based on the fitted distance of each test point in the test area of ​​each test board and the low-temperature mode average distance, the low-temperature mode ranging accuracy of the laser radar corresponding to the calibrated distance of each test board is determined.

[0029] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0030] Obtain the scanning speed corresponding to when the laser radar collects the ranging data of all test points in the test area of ​​each test board;

[0031] The low temperature mode ranging error quality level of the lidar is determined based on the low temperature mode ranging error and the scanning speed of the lidar corresponding to the calibrated distance of each test plate.

[0032] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0033] Obtain the scanning speed corresponding to when the laser radar collects the ranging data of all test points in the test area of ​​each test board;

[0034] The low-temperature mode ranging accuracy quality level of the lidar is determined based on the low-temperature mode ranging accuracy and scanning speed of the lidar corresponding to the calibrated distance of each test plate.

[0035] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0036] The quality level of the laser radar’s ranging temperature drift is determined based on the average distance in high temperature mode and the average distance in low temperature mode of each test board.

[0037] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0038] The fitting polynomial is written into the lidar.

[0039] According to another aspect of the present application, a laser radar ranging error detection system is provided, which implements the method of the above embodiment and / or optional embodiment, wherein the system includes:

[0040] Test bench, several test boards, controllable power supply, temperature chamber and host computer; among them,

[0041] The test bench comprises: a test bench, a laser beam capture camera, an adjustment mechanism and a defogging device;

[0042] The host computer is electrically connected to the test bench and the controllable power supply, respectively, and is used to control the adjustment mechanism, collect laser radar ranging data, and control the laser beam capture camera, the defogger and the controllable power supply, and process the laser radar ranging data;

[0043] The controllable power supply is used to supply power to the test bench and the temperature box.

[0044] Compared with the prior art, the present application provides a method and detection system for fine-tuning the laser radar ranging error. The method includes: obtaining ranging data of test points in a test area of ​​a calibrated test board at a plurality of preset positions collected by the laser radar; determining the first ranging error of the laser radar corresponding to the calibrated distance of each test board based on the ranging data of all test points in the test area of ​​each test board; performing polynomial fitting based on the first ranging error corresponding to the calibrated distance of each test board, and determining the second ranging error of the laser radar corresponding to the calibrated distance of each test board based on the obtained fitting polynomial.

[0045] The technical effect brought by a laser radar ranging error fine-tuning method and detection system provided in the present application is: the laser radar ranging error can be fine-tuned to adapt to the use of a unified standard for ranging error detection of environmental objects with different grayscales, and then the product quality can be directly determined based on the detection results, which can improve the production efficiency and factory qualification rate of mass-produced laser radars. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0047] Attached Figure 1 A schematic diagram showing a LiDAR environment map;

[0048] Attached Figure 2 A schematic diagram showing an exemplary LiDAR range error test board arrangement;

[0049] Attached Figure 3 A schematic diagram showing an exemplary lidar calibration environment;

[0050] Attached Figure 4 A schematic diagram showing an exemplary farthest test plate calibration position;

[0051] Attached Figure 5 A schematic diagram showing a method for fine-tuning a laser radar ranging error according to one aspect of the present application is shown;

[0052] Attached Figure 6 A schematic diagram of the structure of a laser radar ranging error detection system according to another aspect of the present application is shown;

[0053] The same or similar reference numerals in the drawings represent the same or similar components. DETAILED DESCRIPTION

[0054] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0055] As attached Figure 1 As shown, the laser radar A1 emits a laser beam A2, rotates and scans the surrounding environment, and obtains point cloud data based on the received reflected laser beam. 2D plane mapping can be performed to obtain a plane topographic map A4 in the wall A3 of the environment where the current laser radar A1 is located. Using the plane topographic map A4, mapping can be performed in the world coordinate system A5 of the laser radar A1, which can be used for navigation, route planning, etc. In order to ensure the effects of mapping, navigation, and route planning, the laser radar needs to be able to obtain stable and accurate point cloud data, where the point cloud data of each test point obtained includes the distance measurement data, angle data, etc. of the test point, which depends on the relevant parameter indicators determined by the laser radar when it leaves the factory. The quality level of the laser radar can be determined based on the relevant parameter indicators, where the distance measurement error and distance measurement accuracy are important parameter indicators.

[0056] The present application provides a method and a detection system for fine-tuning the laser radar ranging error. The detection system includes: a test bench, several test boards, a controllable power supply, a temperature box, and a host computer. Before using the detection system to detect the laser radar ranging error, calibration is required. Figure 2 , Attachment Figure 3 , Attachment Figure 4As shown, first, the laser radar B1 is placed on the pitch angle adjustment seat B2 of the test bench (the pitch angle adjustment seat is fixed on the test bench B4), and the pitch angle of the laser radar B1 can be adjusted by the pitch angle fine-tuning stepper motor B3; secondly, according to the ranging range of the laser radar B1, the farthest test board B6 is set at the farthest point in the ranging range just in front of the laser beam emission baseline of the laser radar, and the board surface of the test board B6 is adjusted to make it perpendicular to the laser beam emission baseline of the laser radar B1; then, the laser radar B1 is started, and the specific position scanning trajectory C1 reflected by the test board B6 is captured by the laser beam capture camera B7, wherein a high reflectivity area C2 is provided on the board edge of the test board B6, and by adjusting the pitch angle of the laser radar B1, the laser beam capture camera B7 captures the overlapping position C3 of the scanning trajectory C1 and area C2 as the vertical center position of C2, so as to ensure that the scanning trajectory of the laser radar when scanning the farthest test board B6 is the horizontal center line position of B6, so as to complete the scanning positioning and angle determination of the test board B6. The surfaces of other test boards (E1 to E17) are perpendicular to the laser beam emission baseline of the laser radar B1 and their horizontal center lines are in the same horizontal plane as the horizontal center line of the farthest test board B6, so there is no need to calibrate them one by one.

[0057] After completing the calibration of the detection system, the host computer can issue instructions to control the controllable power supply and power on each part. After each part and system completes initialization and self-test, the host computer can obtain the point cloud data of each test board collected by the laser radar, process the point cloud data, calculate the ranging error, and also calculate the ranging accuracy, angular resolution, number of points, laser radar scanning speed, etc. Among them, the ranging data is obtained from the point cloud data, the ranging error of the calibration record of each test board is calculated, and fine-tuning can be performed to determine the ranging error at different distances within the laser radar ranging range to eliminate errors caused by human factors. The ranging data of each test board collected by the laser radar in different temperature modes is also obtained and processed to determine the ranging error and ranging accuracy of different temperature modes.

[0058] In order to further explain the technical means adopted by the present application and the effects achieved, the technical solution of the present application is clearly and completely described below in combination with the accompanying drawings and embodiments and / or optional embodiments.

[0059] In a typical configuration of each embodiment of the present application, the host computer may include one or more types of sensors, one or more processors (CPU), input / output interface, network interface and memory, and corresponding hardware and software. Among them, the memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium. Among them, computer-readable media include permanent and non-permanent, removable and non-removable media can be implemented by any method or technology to store information. Information can be computer program instructions, data structures, modules of programs 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 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 non-transitory media such as modulated data signals and carrier waves.

[0060] Among them, in the calibrated laser radar ranging error detection system, first power on, perform initialization and self-test and other necessary work to ensure that there are no communication connection errors during the operation of the entire system and that the system is powered on normally. Then, the laser radar ranging error can be detected according to the settings in the detection program. Since it is usually necessary to adapt to environmental objects with different grayscales, there is no unified standard for ranging error detection in the prior art, and the product quality cannot be directly determined based on the detection results. In this application, the method for detecting ranging errors can be fine-tuned, and the fine-tuned ranging error can be used to uniformly adapt the ranging error correction of objects with different grayscales. During factory inspection of mass production in factories, the consistency of ranging error performance detection can be guaranteed, thereby improving the factory qualification rate and production efficiency.

[0061] Attached Figure 5 A flow chart of a method for fine-tuning a laser radar ranging error according to one aspect of the present application is shown, wherein the method of an embodiment includes:

[0062] S501 obtains ranging data of test points in a test area of ​​a calibrated test board at a plurality of preset positions collected by a laser radar;

[0063] S502 determines a first ranging error of the laser radar corresponding to a calibrated distance of each test board based on ranging data of all test points in the test area of ​​each test board;

[0064] S503 performs polynomial fitting based on the first ranging error corresponding to the calibrated distance of each test plate, and determines the second ranging error of the laser radar corresponding to the calibrated distance of each test plate based on the obtained fitting polynomial.

[0065] In this embodiment, in step S501, the ranging data of the test points in the test area of ​​the calibrated test board at several preset positions collected by the laser radar can be obtained through the host computer.

[0066] Among them, the host computer obtains and processes the point cloud data of the calibrated test board test area set at several preset positions collected by the laser radar through the communication link between the laser radar, and can obtain the ranging data of the test points in the test area of ​​each test board.

[0067] Among them, at least one side of the test board facing the laser radar includes a test area with a certain size and reflectivity, and the distance between the center position of each test board and the laser radar can be considered as the calibration distance of the test board. Among them, in order to ensure that the ranging data of sufficient test points can be obtained, when calibrating the test board, the radar scanning angle for the test board can be determined according to the test area of ​​the test board, and the point cloud data actually collected including the preset range before and after the calibration distance of the test board is used as the point cloud data of the test area of ​​the test board.

[0068] Continuing with this embodiment, in step S502, the host computer determines the first ranging error of the laser radar corresponding to the calibrated distance of each test board based on the ranging data of all test points in the test area of ​​each test board.

[0069] The host computer can determine the first ranging error of the laser radar corresponding to the calibration distance of the test board based on the ranging data of all test points in the test area of ​​the same test board. By traversing each test board, the first test error of the laser radar corresponding to the calibration distance of each test board can be determined.

[0070] Optionally, the step S502 includes:

[0071] Determine the average distance of the test board based on the acquired ranging data of all test points in the test area of ​​the same test board, and determine the first ranging error of the laser radar corresponding to the calibrated distance of the test board based on the average distance and the calibrated distance of the test board;

[0072] Traverse each test board and determine the first ranging error of the laser radar corresponding to the calibration distance of each test board.

[0073] Among them, the host computer can determine the average distance of the test board based on the ranging data of all test points in the test area of ​​the same test board, wherein the corresponding ranging distance can be determined based on the ranging data of each test point, and the arithmetic mean of the ranging distances of all test points is used as the average distance of the test board. Then, based on the average distance and the calibration distance of the test board, the first ranging error of the laser radar corresponding to the calibrated distance of the test board is determined, wherein the difference between the average distance of the test board and the calibration distance can be determined as the first ranging error corresponding to the calibrated distance of the test board. Then, by traversing each test board, the first ranging error corresponding to the calibrated distance of each test board can be determined.

[0074] Continuing with this embodiment, in step S503, the host computer may perform polynomial fitting according to the first ranging error corresponding to the calibrated distance of each test plate, and determine the second ranging error of the laser radar corresponding to the calibrated distance of each test plate based on the obtained fitting polynomial.

[0075] The host computer can perform polynomial fitting according to the first ranging error corresponding to the calibrated distance of each test board, wherein the order of the polynomial is related to the number of test boards. Exemplarily, the least square method can be used to perform polynomial fitting so that the sum of the squares of the difference between the first ranging error of the calibrated distance of each test board and the polynomial is minimized, thereby determining each coefficient of the fitting polynomial, and the fitting polynomial can be expressed as formula (1):

[0076] P(x)= a N *x N + a N-1 *x N-1 + … + a1*x + a0 (1)

[0077] Among them, after obtaining the fitting polynomial, the second ranging error of the laser radar corresponding to the calibrated distance of each test board can be determined according to the calibrated distance of each test board. In this way, the ranging error distribution of different calibrated distances is relatively uniform within the ranging range of the laser radar, and the second ranging error can be used to uniformly adapt the ranging error correction of objects with different grayscales. Not only can the unified standard of ranging error of environmental objects with different grayscales be adapted, but also the consistency of ranging error performance detection can be ensured during factory batch production and factory inspection, thereby improving the factory qualification rate and production efficiency.

[0078] Optionally, the determining, based on the obtained fitting polynomial, a second ranging error of the laser radar corresponding to the calibrated distance of each test plate comprises:

[0079] The calibrated distance of each test plate is substituted into the obtained fitting polynomial, and the obtained result is determined as the second ranging error of the laser radar corresponding to the calibrated distance of the test plate.

[0080] Among them, after obtaining the fitting polynomial, the calibrated distance of each test plate can be used as x, substituted into the obtained fitting polynomial, and the result is calculated, and the obtained result is determined as the second ranging error of the laser radar corresponding to the calibrated distance of the test plate.

[0081] In order to meet the applicability requirements under different temperature environments, optionally, the method for fine-tuning the laser radar ranging error further includes:

[0082] The laser radar is placed in a temperature box where the temperature inside the box is not lower than a first preset temperature threshold for not less than a first preset time threshold, then taken out, placed on a test bench and calibrated;

[0083] Collecting the ranging data of all the test points in the test area of ​​each test board, and determining the fitting distance of each test point in the test area of ​​each test board and the high temperature mode average distance of each test board based on the ranging data of all the test points in the test area of ​​each test board, and determining the high temperature mode ranging error of the laser radar corresponding to the calibrated distance of each test board based on the high temperature mode average distance of each test board;

[0084] Based on the fitted distance of each test point in the test area of ​​each test board and the average distance in the high temperature mode, the high temperature mode ranging accuracy of the laser radar corresponding to the calibrated distance of each test board is determined.

[0085] In order to determine the ranging error of the laser radar in a high temperature environment, the laser radar can also be placed in a temperature box first, the temperature in the box is not lower than the first preset temperature threshold, and the placement time is not less than the first preset time threshold, and then taken out, placed and fixed on the test bench of the test bench and calibrated to ensure that when the laser beam of the laser radar scans the farthest test board, the scanning track is at its horizontal center line position. After completing power-on, initialization and self-test, the host computer obtains the ranging data of all test points in the test area of ​​each test board collected by the current laser radar, and determines the fitting distance of each test point in the test area of ​​the test board and the average distance of the test board based on the ranging data of all test points in the test area of ​​each test board (the average distance of the test board currently determined can be considered as the average distance of the high temperature mode of the test board), and determines the high temperature mode ranging error of the laser radar corresponding to the calibration distance of the test board based on the average distance of the high temperature mode of each test board.

[0086] Among them, the upper computer can also calculate the difference between the fitting distance of each test point and the average distance of the high temperature mode according to the fitting distance of each test point in the test area of ​​each test board and the average distance of the high temperature mode, and determine the difference with the largest absolute value as the high temperature mode ranging accuracy of the laser radar corresponding to the calibration distance of the test board, so as to determine the ranging accuracy of the laser radar in a high temperature environment.

[0087] Optionally, the determining the fitting distance of each test point in the test area of ​​each test board based on the distance measurement data of all test points in the test area of ​​each test board comprises:

[0088] Based on the acquired distance measurement data of all test points in the test area of ​​the same test board, linear fitting is performed to obtain a fitting straight line corresponding to the test board, and based on the fitting straight line corresponding to the test board, a fitting distance of each test point in the test area of ​​the test board is determined;

[0089] Each test board is traversed to determine the fitting distance for each test point in the test area of ​​each test board.

[0090] Among them, for the same test board, linear fitting is performed based on the distance measurement data of all test points in the test area of ​​the test board to obtain a fitting straight line (for example, the least squares method can be used to fit so that the sum of the squares of the vertical distances from each test point in the test area of ​​the test board to the fitting straight line is minimized). Then the vertical distance from each test point in the test area of ​​the test board to the fitting straight line is calculated as the fitting distance of the corresponding test point in the test area of ​​the test board. By traversing each test board, the fitting distance of each test point in the test area of ​​each test board can be determined.

[0091] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0092] The high temperature mode ranging error quality level of the lidar is determined based on the high temperature mode ranging error of the lidar corresponding to the calibrated distance of each test plate.

[0093] Among them, the high temperature mode ranging error quality level of the laser radar can be determined based on the high temperature mode ranging error of the determined laser radar corresponding to the calibration distance of each test plate, and compared with the established high temperature mode ranging error quality level standard (for example, the value of the high temperature mode ranging error of any calibration distance of the laser radar does not exceed the preset threshold).

[0094] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0095] The high temperature mode ranging accuracy quality level of the lidar is determined based on the high temperature mode ranging accuracy of the lidar corresponding to the calibrated distance of each test plate.

[0096] Among them, the high-temperature mode ranging accuracy quality level of the laser radar can be determined based on the high-temperature mode ranging accuracy of the laser radar corresponding to the calibration distance of each test plate, and compared with the established high-temperature mode ranging accuracy quality level standard (for example, the value of the high-temperature mode ranging accuracy of any calibration distance of the laser radar does not exceed the preset threshold).

[0097] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0098] The laser radar is placed in a temperature box where the temperature inside the box is not higher than a second preset temperature threshold for not less than a second preset time threshold, then taken out, placed on a test bench and calibrated;

[0099] Collecting the ranging data of all the test points in the test area of ​​each test board, and determining the fitting distance of each test point in the test area of ​​each test board and the low temperature mode average distance of each test board based on the ranging data of all the test points in the test area of ​​each test board, and determining the low temperature mode ranging error of the laser radar corresponding to the calibrated distance of each test board based on the low temperature mode average distance of each test board;

[0100] Based on the fitted distance of each test point in the test area of ​​each test board and the low-temperature mode average distance, the low-temperature mode ranging accuracy of the laser radar corresponding to the calibrated distance of each test board is determined.

[0101] In order to determine the ranging error of the laser radar in a low temperature environment, the laser radar can also be placed in a temperature box first, the temperature in the box is not higher than the second preset temperature threshold, and the placement time is not less than the second preset time threshold, and then taken out, placed and fixed on the test bench of the test bench and calibrated to ensure that when the laser beam of the laser radar scans the farthest test board, the scanning trajectory is at its horizontal center line position. After completing power-on, initialization and self-test, the host computer obtains the ranging data of all test points in the test area of ​​each test board collected by the current laser radar, and determines the fitting distance of each test point in the test area of ​​the test board and the average distance of the test board based on the ranging data of all test points in the test area of ​​each test board (the average distance of the test board currently determined can be considered as the average distance of the low temperature mode of the test board), and determines the low temperature mode ranging error of the laser radar corresponding to the calibration distance of the test board based on the average distance of the low temperature mode of each test board. The detection system is equipped with a defogging device to ensure that the laser beam transmitting and receiving window of the laser radar in the low temperature mode will not fog.

[0102] Among them, the upper computer can also calculate the difference between the fitting distance of each test point and the average distance of the low-temperature mode according to the fitting distance of each test point in the test area of ​​each test board and the average distance of the low-temperature mode, and determine the difference with the largest absolute value as the low-temperature mode ranging accuracy of the laser radar corresponding to the calibration distance of the test board, so as to determine the ranging accuracy of the laser radar in a low-temperature environment.

[0103] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0104] Obtain the scanning speed corresponding to when the laser radar collects the ranging data of all test points in the test area of ​​each test board;

[0105] The low temperature mode ranging error quality level of the lidar is determined based on the low temperature mode ranging error and the scanning speed of the lidar corresponding to the calibrated distance of each test plate.

[0106] Among them, the upper computer can also obtain the scanning speed corresponding to the ranging data of all test points in the test area of ​​each test board collected by the laser radar, and determine the low-temperature mode ranging error quality level of the laser radar according to the low-temperature mode ranging error of the calibrated distance of each test board and the scanning speed corresponding to the test board, and compare with the established low-temperature mode ranging error quality level standard (for example, at the prescribed scanning speed, the value of the low-temperature mode ranging error of any calibrated distance of the laser radar does not exceed the preset threshold),

[0107] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0108] Obtain the scanning speed corresponding to when the laser radar collects the ranging data of all test points in the test area of ​​each test board;

[0109] The low-temperature mode ranging accuracy quality level of the lidar is determined based on the low-temperature mode ranging accuracy and scanning speed of the lidar corresponding to the calibrated distance of each test plate.

[0110] Among them, the upper computer can also obtain the scanning speed corresponding to the distance measurement data of all test points in the test area of ​​each test board collected by the laser radar, and determine the low-temperature mode ranging accuracy quality level of the laser radar according to the low-temperature mode ranging accuracy of the calibrated distance of each test board and the scanning speed corresponding to the test board, and compare with the established low-temperature mode ranging accuracy quality level standard (for example, at the prescribed scanning speed, the value of the low-temperature mode ranging accuracy of any calibrated distance of the laser radar does not exceed the preset threshold),

[0111] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0112] The quality level of the laser radar’s ranging temperature drift is determined based on the average distance in high temperature mode and the average distance in low temperature mode of each test board.

[0113] Among them, the host computer can also compare the average distance in high temperature mode and the average distance in low temperature mode of the calibration distance corresponding to each test board of the laser radar, calculate the difference between the two, and compare with the established ranging temperature drift quality level standard (for example, the difference between the average distance in high temperature mode and the average distance in low temperature mode of any calibration distance of the laser radar does not exceed the preset threshold) to determine the ranging temperature drift quality level of the laser radar.

[0114] Optionally, the method for fine-tuning a laser radar ranging error further includes:

[0115] The fitting polynomial is written into the lidar.

[0116] Among them, the host computer also writes the obtained fitting polynomial into the laser radar, which can also be used to correct the ranging error of the laser radar at different ranging distances within the ranging range in actual application scenarios.

[0117] Figure 6 A laser radar ranging error detection system according to another aspect of the present application is shown, which is used to implement the above method embodiment and / or optional embodiment, wherein the system of one embodiment includes:

[0118] Test bench 610, several test boards 620, controllable power supply 630, temperature box 640 and host computer 650; wherein,

[0119] The test bench 610 includes: a test bench 611, a laser beam capture camera 612, an adjustment mechanism 613 and a defogging device 614;

[0120] The host computer 650 is electrically connected to the test bench 610 and the controllable power supply 630, respectively, and is used to control the adjustment mechanism 613, collect the laser radar ranging data, and control the laser beam capture camera 612, the defogging device 614 and the controllable power supply 630, and process the laser radar ranging data;

[0121] The controllable power supply 630 is used to supply power to the test bench 610 and the temperature chamber 640 .

[0122] Before the detection system starts working, calibration is performed first, wherein the laser beam reflected by the farthest test board 620 is captured by the laser beam capture camera 612 to obtain corresponding image data. The upper computer determines whether the laser beam trajectory of the laser radar is at the horizontal center line position of the farthest test board 620 based on the acquired image data. If not, the adjustment mechanism 613 is adjusted to ensure that the laser beam trajectory of the laser radar is at the horizontal center line position of the farthest test board 620 (the horizontal center line of the test board 620 at other calibration positions is in the same horizontal plane as the horizontal center line of the farthest test board 620), and the calibration is completed.

[0123] Among them, the controllable power supply 630 is used to power the test bench 610 (including the laser radar placed on the test bench 611) and the temperature box 640. The system is first powered on and started, and the initialization and self-test are completed, including the control information of the controllable power supply 630, the interface connection communication of the laser radar, the image capture information of the laser beam capture camera 612, the control information of the adjustment mechanism 613, and the network connection information, etc., to ensure that there are no errors in the communication connection during the operation of the entire system and to ensure the normal power supply of the system. As an exemplary example, the host computer 650 can send control instructions to the controllable power supply 630 through a network that supports the modbus protocol, and control the controllable power supply 630 to power the test bench 610 and the temperature box 640.

[0124] Among them, in the calibration stage, the host computer 650 can obtain the image data collected by the laser beam capture camera 612 through the USB interface or other methods, and process it to determine whether the scanning trajectory of the laser beam scanning at the farthest test board B6 is in the horizontal center line position. If not, it can send a control instruction to the adjustment mechanism 613 through the network (an exemplary network that supports the modbus protocol) to control the adjustment mechanism 613 to adjust the pitch angle of the laser radar so that the scanning trajectory of the laser beam scanning at the farthest test board B6 is in the horizontal center line position to complete the calibration. Then, the host computer 650 can obtain the point cloud data of each test board 620 collected by the laser radar through a virtual serial port or other methods, including the ranging data of all test points in the test area of ​​each test board 620 (the distance and angle from the test point to the laser radar), calculate the ranging error, ranging accuracy, etc., and can determine the quality level of the relevant parameter indicators in combination with the scanning speed of the corresponding laser radar. It can also be fine-tuned for the ranging error to eliminate the error caused by human factors. Furthermore, the ranging error and ranging accuracy under different temperature environments can be detected, and the ranging error quality level, ranging accuracy quality level, and ranging temperature drift quality level in high temperature mode and low temperature mode can be determined. In the low temperature mode, a defogger 614 can also be used to prevent the window from fogging when the laser radar is working. The specific detection method steps can refer to the above method embodiments and / or optional embodiments, and will not be elaborated here.

[0125] According to another aspect of the present application, a computer-readable medium is provided, wherein the computer-readable medium stores computer program instructions, and the computer program instructions can be executed by a processor to cooperate in implementing the aforementioned method embodiments and / or optional embodiments.

[0126] It should be noted that each method embodiment and / or optional embodiment in the present application can be implemented in software and / or a combination of software and hardware. The software program involved in the present application can be executed by a processor to implement the steps or functions of the above-mentioned embodiments. Similarly, the software program (including related data structures) of the present application can be stored in a computer-readable recording medium.

[0127] In addition, a part of the present application may be applied as a computer program product, such as a computer program instruction and / or a computer program interface, which, when executed by a computer, can call or provide the method and / or technical solution according to the present application through the operation of the computer. The program instruction for calling the method of the present application may be stored in a fixed or removable recording medium, and / or transmitted through a data stream in a broadcast or other signal-bearing medium, and / or stored in a working memory of a computer device that runs according to the program instruction.

[0128] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices stated in the device claim can also be implemented by one unit or device through software and / or hardware. The words first, second, etc. are used to indicate names, and do not indicate any particular order.

Claims

1. A method for fine-tuning laser radar ranging error, characterized in that: The method comprises: Obtaining ranging data of test points in a test area of ​​a calibrated test board at a plurality of preset positions collected by a laser radar; Determine a first ranging error of the laser radar corresponding to the calibrated distance of each test board based on the ranging data of all test points in the test area of ​​each test board; Based on the first ranging error corresponding to the calibrated distance of each test plate, a polynomial fitting is performed, and based on the obtained fitting polynomial, the second ranging error of the laser radar corresponding to the calibrated distance of each test plate is determined.

2. The method according to claim 1, characterized in that: Determining the first ranging error of the laser radar corresponding to the calibrated distance of each test board based on the ranging data of all test points in the test area of ​​each test board includes: Determine the average distance of the test board based on the acquired ranging data of all test points in the test area of ​​the same test board, and determine the first ranging error of the laser radar corresponding to the calibrated distance of the test board based on the average distance and the calibrated distance of the test board; Traverse each test board and determine the first ranging error of the laser radar corresponding to the calibration distance of each test board.

3. The method according to claim 1, characterized in that Determining the second ranging error of the laser radar corresponding to the calibrated distance of each test plate based on the obtained fitting polynomial includes: The calibrated distance of each test plate is substituted into the obtained fitting polynomial, and the obtained result is determined as the second ranging error of the laser radar corresponding to the calibrated distance of the test plate.

4. The method according to claim 1, characterized in that: The method further comprises: The laser radar is placed in a temperature box where the temperature inside the box is not lower than a first preset temperature threshold for not less than a first preset time threshold, then taken out, placed on a test bench and calibrated; Collecting the ranging data of all the test points in the test area of ​​each test board, and determining the fitting distance of each test point in the test area of ​​each test board and the high temperature mode average distance of each test board based on the ranging data of all the test points in the test area of ​​each test board, and determining the high temperature mode ranging error of the laser radar corresponding to the calibrated distance of each test board based on the high temperature mode average distance of each test board; Based on the fitted distance of each test point in the test area of ​​each test board and the average distance in the high temperature mode, the high temperature mode ranging accuracy of the laser radar corresponding to the calibrated distance of each test board is determined.

5. The method according to claim 4, characterized in that Determining the fitting distance of each test point in the test area of ​​each test board based on the distance measurement data of all test points in the test area of ​​each test board includes: Based on the acquired distance measurement data of all test points in the test area of ​​the same test board, linear fitting is performed to obtain a fitting straight line corresponding to the test board, and based on the fitting straight line corresponding to the test board, a fitting distance of each test point in the test area of ​​the test board is determined; Each test board is traversed to determine the fitting distance for each test point in the test area of ​​each test board.

6. The method according to claim 4, characterized in that The method further comprises: The high temperature mode ranging error quality level of the lidar is determined based on the high temperature mode ranging error of the lidar corresponding to the calibrated distance of each test plate.

7. The method according to claim 4, characterized in that The method further comprises: The high temperature mode ranging accuracy quality level of the lidar is determined based on the high temperature mode ranging accuracy of the lidar corresponding to the calibrated distance of each test plate.

8. The method according to claim 4, characterized in that The method further comprises: The laser radar is placed in a temperature box where the temperature inside the box is not higher than a second preset temperature threshold for not less than a second preset time threshold, then taken out, placed on a test bench and calibrated; Collecting the ranging data of all the test points in the test area of ​​each test board, and determining the fitting distance of each test point in the test area of ​​each test board and the low temperature mode average distance of each test board based on the ranging data of all the test points in the test area of ​​each test board, and determining the low temperature mode ranging error of the laser radar corresponding to the calibrated distance of each test board based on the low temperature mode average distance of each test board; Based on the fitted distance of each test point in the test area of ​​each test board and the low-temperature mode average distance, the low-temperature mode ranging accuracy of the laser radar corresponding to the calibrated distance of each test board is determined.

9. The method according to claim 8, characterized in that The method further comprises: Obtain the scanning speed corresponding to when the laser radar collects the ranging data of all test points in the test area of ​​each test board; The low temperature mode ranging error quality level of the lidar is determined based on the low temperature mode ranging error and the scanning speed of the lidar corresponding to the calibrated distance of each test plate.

10. The method according to claim 8, characterized in that The method further comprises: Obtain the scanning speed corresponding to when the laser radar collects the ranging data of all test points in the test area of ​​each test board; The low-temperature mode ranging accuracy quality level of the lidar is determined based on the low-temperature mode ranging accuracy and scanning speed of the lidar corresponding to the calibrated distance of each test plate.

11. The method according to claim 8, characterized in that The method further comprises: The quality level of the laser radar’s ranging temperature drift is determined based on the average distance in high temperature mode and the average distance in low temperature mode of each test board.

12. The method according to claim 1, characterized in that The method further comprises: The fitting polynomial is written into the lidar.

13. A detection system for implementing the method according to any one of claims 1 to 12, characterized in that: The system comprises: Test bench, several test boards, controllable power supply, temperature chamber and host computer; among them, The test bench comprises: a test bench, a laser beam capture camera, an adjustment mechanism and a defogging device; The host computer is electrically connected to the test bench and the controllable power supply, respectively, and is used to control the adjustment mechanism, collect laser radar ranging data, and control the laser beam capture camera, the defogger and the controllable power supply, and process the laser radar ranging data; The controllable power supply is used to supply power to the test bench and the temperature box.

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