Laser radar calibration method and device, equipment and storage medium

Abstract

The invention discloses a laser radar calibration method, device and equipment and a storage medium, and relates to the technical field of distance calibration, and the method comprises the steps that a laser radar is controlled to emit laser scanning points and receive distance measurement data, the laser radar is located on a rotatable turntable, and the turntable is located in a room with four walls being reflecting surfaces; acquiring a real distance value between the central position of the rotary table and the reflecting surface; acquiring a laser reflection pulse energy value set and a distance measurement value set of the laser scanning point according to the distance measurement data; determining a calibration compensation amount set of the laser scanning point according to the distance measurement data, the real distance value and the distance measurement value set; and establishing a calibration mapping table according to the calibration compensation amount set, the laser reflection pulse energy value set and the ranging value set, and realizing calibration of the laser radar according to the calibration mapping table. According to the invention, the laser radar calibration efficiency can be improved.

Description

Technical Field

[0001] This application relates to the field of distance calibration technology, and in particular to a calibration method, apparatus, device, and storage medium for lidar. Background Art

[0002] Currently, lidar calibration technology requires the use of complex equipment such as guide rails to determine the compensation parameters of the lidar at different distances. Due to the limited movement speed of the guide rails, the calibration process is time-consuming and inefficient. Therefore, improving the efficiency of lidar calibration remains a problem that needs to be solved. Summary of the Invention

[0003] The main objective of this application is to provide a calibration method, apparatus, device, and storage medium for lidar, aiming to solve the technical problem of how to improve the efficiency of lidar calibration.

[0004] To achieve the above objectives, this application proposes a calibration method for lidar, the method comprising:

[0005] The system controls a lidar to emit laser scanning points and receive ranging data. The lidar is located on a rotatable turntable in a room where all four walls are reflective surfaces.

[0006] Obtain the actual distance between the center position of the turntable and the reflective surface;

[0007] Based on the ranging data, obtain the set of laser reflection pulse energy values ​​and the set of ranging values ​​for the laser scanning point;

[0008] The calibration compensation set of the laser scanning point is determined based on the ranging data, the actual distance value, and the set of ranging values.

[0009] A calibration mapping table is established based on the calibration compensation set, the laser reflection pulse energy value set, and the ranging value set, and the calibration of the lidar is achieved based on the calibration mapping table.

[0010] In one embodiment, the step of determining the calibration compensation set of the laser scanning point based on the ranging data, the actual distance value, and the set of ranging values ​​includes:

[0011] Determine the local extreme range laser scanning point based on the ranging data;

[0012] The angle between the emission paths of other laser points and the emission path of the local extreme laser scanning point is determined based on the ranging data.

[0013] The true distance value is used as the actual distance value of the local ranging extreme value laser scanning point, and the set of actual distance values ​​of other laser points is determined based on the actual distance value and the included angle.

[0014] The calibration compensation set is determined based on the set of actual distance values ​​and the set of distance measurements.

[0015] In one embodiment, the step of determining the local extreme value laser scanning point based on the ranging data includes:

[0016] The target distance values ​​at different times of the laser scanning point are compared based on the distance measurement data.

[0017] When the target ranging value is detected to decrease and then increase again, the laser scanning point corresponding to the minimum ranging value after the decrease is taken as the local ranging extreme value laser scanning point.

[0018] If the target ranging value is detected to increase and then increase again, the laser scanning point corresponding to the maximum ranging value after the increase is taken as the local ranging extreme value laser scanning point.

[0019] In one embodiment, the step of determining the angle between the emission paths of other laser points and the emission path of the local ranging extreme value laser scanning point based on the ranging data includes:

[0020] Other laser points are classified, and the laser scanning points emitted by the transmitter of the local ranging extreme value laser scanning point are classified as the first type of laser scanning points, and the remaining laser scanning points are classified as the second type of laser scanning points.

[0021] Calculate the horizontal angle between the emission path of the first type of laser scanning point and the emission path of the local extreme laser scanning point based on the ranging data;

[0022] Calculate the horizontal and vertical angles between the emission path of the second type of laser scanning point and the emission path of the local ranging extreme value laser scanning point based on the ranging data.

[0023] In one embodiment, the step of determining the set of actual distance values ​​for other laser points based on the actual distance value and the included angle includes:

[0024] The calculation method is determined based on the local extreme value laser scanning points for ranging.

[0025] The actual distance value and the included angle are calculated according to the calculation method to obtain a set of actual distance values.

[0026] In one embodiment, the step of determining the calibration compensation set based on the actual distance value set and the ranging value set includes:

[0027] Determine the correspondence between distance value elements in the actual distance value set and distance value elements in the distance measurement value set;

[0028] Based on the correspondence, subtract the corresponding distance value element from each of the ranging value elements to obtain the calibration compensation set.

[0029] In one embodiment, the step of establishing a calibration mapping table based on the calibration compensation set, the laser reflection pulse energy value set, and the ranging value set includes:

[0030] The calibration compensation amount, laser reflection pulse energy value, and ranging value of all laser scanning points are determined based on the calibration compensation amount set, the laser reflection pulse energy value set, and the ranging value set.

[0031] Record the calibration compensation values ​​corresponding to the laser reflection pulse energy values ​​and ranging values ​​of all the laser scanning points to obtain a calibration mapping table.

[0032] Furthermore, to achieve the above objectives, this application also proposes a calibration device for a lidar, the lidar calibration device comprising:

[0033] A transmitting module is used to control the lidar to emit laser scanning points and receive ranging data. The lidar is located on a rotatable turntable, which is located in a room with four reflective walls.

[0034] The acquisition module is used to acquire the actual distance between the center position of the turntable and the reflective surface;

[0035] The calculation module is used to obtain the set of laser reflection pulse energy values ​​and the set of distance values ​​of the laser scanning point based on the ranging data;

[0036] The determination module is used to determine the calibration compensation set of the laser scanning point based on the ranging data, the actual distance value, and the ranging value set;

[0037] The calibration module is used to establish a calibration mapping table based on the calibration compensation set, the laser reflection pulse energy value set, and the ranging value set, and to calibrate the lidar based on the calibration mapping table.

[0038] In addition, to achieve the above objectives, this application also proposes a calibration device for lidar, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the lidar calibration method described above.

[0039] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the lidar calibration method described above.

[0040] In addition, to achieve the above objectives, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the lidar calibration method described above.

[0041] This application provides a calibration method for a lidar. The method involves controlling the lidar to emit laser scanning points and receive ranging data. The lidar is located on a rotatable turntable in a room with four reflective walls. The method involves obtaining the true distance between the center of the turntable and the reflective surfaces; acquiring a set of laser reflection pulse energy values ​​and a set of ranging values ​​for the laser scanning points based on the ranging data; determining a set of calibration compensation values ​​for the laser scanning points based on the ranging data, the true distance values, and the set of ranging values; establishing a calibration mapping table based on the calibration compensation table, the set of laser reflection pulse energy values, and the set of ranging values; and calibrating the lidar based on the calibration mapping table.

[0042] In summary, this application uses a turntable to carry the lidar, automatically selects the calibration record position based on the extreme distance measurement point during the rotation process, and constructs a calibration mapping table by combining the laser reflection pulse energy and the measured distance for calibration, thereby improving the efficiency of lidar calibration. Attached Figure Description

[0043] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A schematic flowchart of the calibration method for the lidar in this application is provided in Embodiment 1.

[0046] Figure 2 A schematic diagram of a calibration scenario provided for Embodiment 1 of the calibration method for the lidar of this application;

[0047] Figure 3A schematic diagram of the reflective surface provided in Embodiment 1 of the calibration method for the lidar of this application;

[0048] Figure 4 A schematic flowchart illustrating the calibration method for the lidar in Embodiment 2 of this application;

[0049] Figure 5 This is a schematic diagram of the module structure of the lidar calibration device according to an embodiment of this application;

[0050] Figure 6 This is a schematic diagram of the device structure of the hardware operating environment involved in the calibration method of the lidar in this application embodiment.

[0051] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0052] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0053] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0054] The main solution of this application is to control a lidar to emit laser scanning points and receive ranging data. The lidar is located on a rotatable turntable in a room with four reflective walls. The solution involves: obtaining the true distance between the center of the turntable and the reflective surfaces; obtaining a set of laser reflection pulse energy values ​​and a set of ranging values ​​for the laser scanning points based on the ranging data; determining a set of calibration compensation values ​​for the laser scanning points based on the ranging data, the true distance values, and the set of ranging values; establishing a calibration mapping table based on the calibration compensation value set, the set of laser reflection pulse energy values, and the set of ranging values; and calibrating the lidar based on the calibration mapping table.

[0055] Currently, lidar calibration technology requires the use of complex equipment such as guide rails to determine the compensation parameters of the lidar at different distances. Due to the limited movement speed of the guide rails, the calibration process is time-consuming and inefficient. Therefore, improving the efficiency of lidar calibration remains a problem that needs to be solved.

[0056] This application uses a turntable to carry the lidar, automatically selects the calibration record position based on the extreme distance measurement point during the rotation process, and constructs a calibration mapping table by combining the laser reflection pulse energy and the measured distance for calibration, thereby improving the efficiency of lidar calibration.

[0057] Based on this, embodiments of this application provide a calibration method for lidar, referring to... Figure 1, Figure 1 This is a flowchart illustrating the first embodiment of the lidar calibration method of this application.

[0058] In this embodiment, the calibration method for the lidar includes steps S10 to S50:

[0059] Step S10: Control the lidar to emit laser scanning points and receive ranging data, wherein the lidar is located on a rotatable turntable, and the turntable is located in a room with four walls that are reflective.

[0060] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or an electronic device capable of performing the above functions, such as a lidar calibration device. The following description uses a lidar calibration device as an example to illustrate this embodiment and the subsequent embodiments.

[0061] It should be noted that in this embodiment, the lidar is located on a rotatable turntable, which is situated in a room where all four walls are reflective surfaces. (See reference...) Figure 2 , Figure 2 This is a schematic diagram of the calibration scenario. Figure 2 This is a top-down view. The lidar is located on a turntable. The line connecting the center point of the lidar and the center point of the turntable is parallel to the Z-axis of the room, which is perpendicular to the page. The lidar can rotate around the Z-axis. The lidar and the turntable are located in a room with reflective surfaces on all four sides. Multiple laser scanning lines emitted by the lidar measure the distance to the reflective surfaces for calibration. The reflective surfaces installed on the four walls can be referenced. Figure 3 , Figure 3 This is a schematic diagram of the reflective surface. Figure 3 The reflective surfaces include three reflectivity levels: 80%, 10%, and greater than 100%.

[0062] Step S20: Obtain the actual distance between the center position of the turntable and the reflective surface;

[0063] Understandably, the actual distance between the center of the turntable and the reflective surface is obtained using a measuring tape or rangefinder, and can be considered an accurate value. The lidar will then be calibrated based on this actual distance.

[0064] Step S30: Obtain the set of laser reflection pulse energy values ​​and the set of distance values ​​for the laser scanning point based on the ranging data;

[0065] Understandably, all data collected by lidar is ranging data, which includes at least the lidar's measured distance, horizontal angle, vertical angle, and laser reflection pulse energy value.

[0066] Step S40: Determine the calibration compensation set for the laser scanning point based on the ranging data, the actual distance value, and the set of ranging values;

[0067] Understandably, given the ranging data, the actual distance value, and the set of ranging values, the calibration compensation amount for each laser scanning point can be calculated, and the calibration compensation amounts for all laser scanning points constitute the calibration compensation amount set.

[0068] Step S50: Establish a calibration mapping table based on the calibration compensation set, the laser reflection pulse energy value set, and the ranging value set, and calibrate the lidar based on the calibration mapping table.

[0069] Understandably, when using lidar for actual ranging, the compensation value can be determined by using a calibration mapping table based on the lidar's ranging value and the laser reflection pulse energy, thus achieving lidar calibration.

[0070] In one feasible approach, the step of establishing a calibration mapping table based on the calibration compensation set, the laser reflection pulse energy value set, and the ranging value set includes: determining the calibration compensation amount, laser reflection pulse energy value, and ranging value of all the laser scanning points based on the calibration compensation set, the laser reflection pulse energy value set, and the ranging value set; recording the calibration compensation amount corresponding to the laser reflection pulse energy value and the ranging value of all the laser scanning points to obtain the calibration mapping table.

[0071] It should be noted that the calibration mapping table in this embodiment is the corresponding compensation value when the lidar ranging value and the laser reflection pulse energy are determined.

[0072] This embodiment controls a lidar to emit laser scanning points and receive ranging data. The lidar is located on a rotatable turntable in a room with four reflective walls. The true distance between the center of the turntable and the reflective surfaces is obtained. Based on the ranging data, a set of laser reflection pulse energy values ​​and a set of ranging values ​​for the laser scanning points are obtained. A set of calibration compensation values ​​for the laser scanning points is determined based on the ranging data, the true distance values, and the set of ranging values. A calibration mapping table is established based on the calibration compensation value set, the set of laser reflection pulse energy values, and the set of ranging values, and the lidar is calibrated according to the calibration mapping table.

[0073] In summary, this embodiment uses a turntable to carry the lidar, automatically selects the calibration recording position based on the extreme distance measurement point during the rotation process, and constructs a calibration mapping table by combining the laser reflection pulse energy and the measured distance for calibration, thereby improving the efficiency of lidar calibration.

[0074] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment described above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 4 Step S40 further includes steps S401 to S404:

[0075] Step S401: Determine the local extreme range laser scanning point based on the ranging data;

[0076] Understandably, local ranging extreme values ​​of laser scanning points include both maximum and minimum values. When the lidar rotates, the ranging value of each laser scanning line will have 8 extreme values. Within the rectangular space formed by the four reflectors, when the laser scanning line measures the distance to the vertex, it obtains 4 local maximum values; when the laser scanning line is perpendicular to the four panels, it obtains 4 local minimum values.

[0077] In one feasible approach, the step of determining the local extreme range laser scanning point based on the ranging data includes: comparing the target ranging value of the laser scanning point at different times based on the ranging data; when it is detected that the target ranging value decreases and then increases again, the laser scanning point corresponding to the minimum ranging value after the decrease is taken as the local extreme range laser scanning point; when it is detected that the target ranging value increases and then increases again, the laser scanning point corresponding to the maximum ranging value after the increase is taken as the local extreme range laser scanning point.

[0078] It should be noted that when determining the local extreme value laser scanning point from the collected ranging data, it can be determined based on the target ranging value at different times. When the target ranging value first decreases and then increases, the local extreme value laser scanning point can be determined based on the minimum ranging value, which is the local minimum value. When the target ranging value first increases and then decreases, the local extreme value laser scanning point can be determined based on the maximum ranging value, which is the local maximum value.

[0079] Step S402: Determine the angle between the emission paths of other laser points and the emission path of the local ranging extreme value laser scanning point based on the ranging data;

[0080] It should be noted that since the true distance of the local ranging extreme value laser scanning point can be obtained, it is only necessary to obtain the angle between the emission path of other laser points and the emission path of the local ranging extreme value laser scanning point to calculate the true distance of all laser scanning points.

[0081] In one feasible approach, the step of determining the angle between the emission paths of other laser points and the emission path of the local extreme range laser scanning point based on the ranging data includes: classifying the other laser points, designating the laser scanning points emitted by the transmitter of the local extreme range laser scanning point as first-class laser scanning points, and the remaining laser scanning points as second-class laser scanning points; calculating the horizontal angle between the emission paths of the first-class laser scanning points and the emission path of the local extreme range laser scanning point based on the ranging data; and calculating the horizontal and vertical angles between the emission paths of the second-class laser scanning points and the emission path of the local extreme range laser scanning point based on the ranging data.

[0082] Understandably, the horizontal angle θ(t, n) between the scanning point in a single laser scanning line and the local extreme laser scanning point can be obtained from the ranging data, where t is the time and n is the laser scanning line n where the local extreme laser scanning point is located; the vertical angle ω(n, m) between other lines m and line n can also be obtained from the ranging data.

[0083] Step S403: Use the true distance value as the actual distance value of the local ranging extreme value laser scanning point, and determine the set of actual distance values ​​of other laser points based on the actual distance value and the included angle;

[0084] It should be noted that for local extreme distance laser scanning points, the actual distance value measured by the measuring tape can be used as the actual distance value, while for other laser points, the corresponding set of actual distance values ​​can be calculated based on the included angle and the actual distance value.

[0085] In one feasible approach, the step of determining the set of actual distance values ​​of other laser points based on the actual distance value and the included angle includes: determining a calculation method based on the local ranging extreme value laser scanning point; and calculating the actual distance value and the included angle based on the calculation method to obtain the set of actual distance values.

[0086] It should be noted that since the local ranging extreme value laser scanning point is divided into two cases: maximum and minimum, the calculation methods are also different. This embodiment takes the minimum value as an example, that is, when the local ranging extreme value laser scanning point is perpendicular to the reflecting surface, the actual distance value is calculated as r(t, n) = r × cos(θ(t, n)) for the first type of laser scanning point, and as r(t, m) = r × cos(ω(n, m)) × cos(θ(t, m)) for the second type of laser scanning point. If the local ranging extreme value laser scanning point is a maximum value, the included angle value needs to be converted to supplementary angle before calculation.

[0087] Step S404: Determine the calibration compensation set based on the actual distance value set and the distance measurement value set.

[0088] In one feasible approach, the step of determining the calibration compensation set based on the actual distance value set and the ranging value set includes: determining the correspondence between distance value elements in the actual distance value set and ranging value elements in the ranging value set; and subtracting the corresponding distance value element from each ranging value element according to the correspondence to obtain the calibration compensation set.

[0089] It should be noted that if the measured values ​​of each laser scanning line are d(t,n) and d(t,m), and the laser pulse reflection energy values ​​of each laser scanning line are e(t,n) and e(t,m), then the calibration compensation amounts are c(t,n) = d(t,n) - r(t,n) and c(t,m) = d(t,m) - r(t,m). After the lidar rotates one revolution, each laser scanning line obtains multiple sets of (d, e, c) data, thus obtaining the calibration compensation amount set.

[0090] This embodiment determines the local extreme range laser scanning point based on the ranging data; it determines the angle between the emission paths of other laser points and the emission path of the local extreme range laser scanning point based on the ranging data; it uses the true distance value as the actual distance value of the local extreme range laser scanning point, and determines the set of actual distance values ​​of other laser points based on the actual distance value and the angle; it determines the set of calibration compensation values ​​based on the set of actual distance values ​​and the set of ranging values. This embodiment obtains the compensation value of a laser scanning point by measuring data with a measuring tape, and calculates the compensation values ​​of all laser scanning points based on the angle, which can quickly obtain the set of calibration compensation values ​​for laser scanning points, thereby improving the calibration efficiency of the lidar.

[0091] This application also provides a calibration device for lidar, please refer to... Figure 5 The calibration device for the lidar includes:

[0092] The transmitting module 10 is used to control the lidar to emit laser scanning points and receive ranging data. The lidar is located on a rotatable turntable, which is located in a room where all four walls are reflective surfaces.

[0093] The acquisition module 20 is used to acquire the actual distance value between the center position of the turntable and the reflective surface;

[0094] Calculation module 30 is used to obtain the set of laser reflection pulse energy values ​​and the set of distance values ​​of the laser scanning point based on the ranging data;

[0095] The determining module 40 is used to determine the calibration compensation set of the laser scanning point based on the ranging data, the actual distance value, and the ranging value set;

[0096] The calibration module 50 is used to establish a calibration mapping table based on the calibration compensation set, the laser reflection pulse energy value set, and the ranging value set, and to calibrate the lidar based on the calibration mapping table.

[0097] This embodiment controls a lidar to emit laser scanning points and receive ranging data. The lidar is located on a rotatable turntable in a room with four reflective walls. The true distance between the center of the turntable and the reflective surfaces is obtained. Based on the ranging data, a set of laser reflection pulse energy values ​​and a set of ranging values ​​for the laser scanning points are obtained. A set of calibration compensation values ​​for the laser scanning points is determined based on the ranging data, the true distance values, and the set of ranging values. A calibration mapping table is established based on the calibration compensation value set, the set of laser reflection pulse energy values, and the set of ranging values, and the lidar is calibrated according to the calibration mapping table.

[0098] In summary, this embodiment uses a turntable to carry the lidar, automatically selects the calibration recording position based on the extreme distance measurement point during the rotation process, and constructs a calibration mapping table by combining the laser reflection pulse energy and the measured distance for calibration, thereby improving the efficiency of lidar calibration.

[0099] In one embodiment, the determining module 40 is further configured to: determine a local extreme laser scanning point based on the ranging data; determine the angle between the emission paths of other laser points and the emission path of the local extreme laser scanning point based on the ranging data; use the true distance value as the actual distance value of the local extreme laser scanning point, and determine a set of actual distance values ​​of other laser points based on the actual distance value and the angle; and determine a set of calibration compensation amounts based on the set of actual distance values ​​and the set of ranging values.

[0100] In one embodiment, the determining module 40 is further configured to compare the target ranging value of the laser scanning point at different times based on the ranging data; when it is detected that the target ranging value decreases and then increases, the laser scanning point corresponding to the minimum ranging value after the decrease is taken as the local ranging extreme laser scanning point; when it is detected that the target ranging value increases and then increases, the laser scanning point corresponding to the maximum ranging value after the increase is taken as the local ranging extreme laser scanning point.

[0101] In one embodiment, the determining module 40 is further configured to classify other laser points, designating the laser scanning points emitted by the transmitter of the local ranging extreme laser scanning point as first-class laser scanning points and the remaining laser scanning points as second-class laser scanning points; calculating the horizontal angle between the emission path of the first-class laser scanning points and the emission path of the local ranging extreme laser scanning point based on the ranging data; and calculating the horizontal and vertical angles between the emission path of the second-class laser scanning points and the emission path of the local ranging extreme laser scanning point based on the ranging data.

[0102] In one embodiment, the determining module 40 is further configured to determine a calculation method based on the local ranging extreme value laser scanning point; and to calculate the actual distance value and the included angle based on the calculation method to obtain a set of actual distance values.

[0103] In one embodiment, the determining module 40 is further configured to determine the correspondence between distance value elements in the actual distance value set and distance value elements in the distance measurement value set; and subtract the corresponding distance value element from the distance measurement value element according to the correspondence to obtain a calibration compensation set.

[0104] In one embodiment, the calibration module 50 is further configured to determine the calibration compensation amount, laser reflection pulse energy value, and ranging value of all the laser scanning points based on the calibration compensation amount set, the laser reflection pulse energy value set, and the ranging value set; record the calibration compensation amount corresponding to the laser reflection pulse energy value and the ranging value of all the laser scanning points to obtain a calibration mapping table.

[0105] The lidar calibration device provided in this application, employing the lidar calibration method described in the above embodiments, can solve the technical problem of how to improve the efficiency of lidar calibration. Compared with the prior art, the beneficial effects of the lidar calibration device provided in this application are the same as those of the lidar calibration method provided in the above embodiments, and other technical features in the lidar calibration device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0106] This application provides a calibration device for a lidar, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which are executed by the at least one processor to enable the at least one processor to perform the lidar calibration method in Embodiment 1 above.

[0107] The following is for reference. Figure 6The diagram illustrates a structural schematic of a calibration device suitable for implementing the embodiments of this application for LiDAR. The calibration device for LiDAR in the embodiments of this application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), in-vehicle terminals (e.g., in-vehicle navigation terminals), and fixed terminals such as digital TVs and desktop computers. Figure 6 The lidar calibration device shown is merely an example and should not be construed as limiting the functionality and scope of the embodiments of this application.

[0108] like Figure 6 As shown, the lidar calibration device may include a processing unit 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in ROM (Read Only Memory) 1002 or a program loaded from storage device 1003 into RAM (Random Access Memory) 1004. RAM 1004 also stores various programs and data required for the operation of the lidar calibration device. The processing unit 1001, ROM 1002, and RAM 1004 are interconnected via bus 1005. Input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to I / O interface 1006: input devices 1007 including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 1008 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1003 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1009. Communication device 1009 allows the lidar calibration equipment to communicate wirelessly or wiredly with other devices to exchange data. While the figures show lidar calibration equipment with various systems, it should be understood that implementing or having all of the systems shown is not required. More or fewer systems may be implemented alternatively.

[0109] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from ROM 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0110] The lidar calibration device provided in this application, employing the lidar calibration method described in the above embodiments, can solve the technical problem of how to improve the efficiency of lidar calibration. Compared with the prior art, the beneficial effects of the lidar calibration device provided in this application are the same as those of the lidar calibration method provided in the above embodiments, and other technical features of this lidar calibration device are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0111] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0112] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0113] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the lidar calibration method in the above embodiments.

[0114] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0115] The aforementioned computer-readable storage medium may be included in the calibration equipment of the lidar; or it may exist independently and not assembled into the calibration equipment of the lidar.

[0116] The aforementioned computer-readable storage medium carries one or more programs that, when executed by a lidar calibration device, cause the lidar calibration device to: control the lidar to emit laser scanning points and receive ranging data, wherein the lidar is located on a rotatable turntable in a room with four reflective walls; acquire the true distance value between the center position of the turntable and the reflective surfaces; acquire a set of laser reflection pulse energy values ​​and a set of ranging values ​​for the laser scanning points based on the ranging data; determine a set of calibration compensation values ​​for the laser scanning points based on the ranging data, the true distance values, and the set of ranging values; establish a calibration mapping table based on the calibration compensation value set, the set of laser reflection pulse energy values, and the set of ranging values, and perform lidar calibration based on the calibration mapping table.

[0117] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0118] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0119] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0120] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described lidar calibration method, thereby solving the technical problem of how to improve the efficiency of lidar calibration. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the lidar calibration method provided in the above embodiments, and will not be repeated here.

[0121] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the lidar calibration method described above.

[0122] The computer program product provided in this application solves the technical problem of how to improve the efficiency of lidar calibration. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the lidar calibration method provided in the above embodiments, and will not be repeated here.

[0123] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A calibration method for a lidar, characterized in that, The method includes: The system controls a lidar to emit laser scanning points and receive ranging data. The lidar is located on a rotatable turntable in a room where all four walls are reflective surfaces. Obtain the actual distance between the center position of the turntable and the reflective surface; Based on the ranging data, obtain the set of laser reflection pulse energy values ​​and the set of ranging values ​​for the laser scanning point; The calibration compensation set of the laser scanning point is determined based on the ranging data, the actual distance value, and the set of ranging values. A calibration mapping table is established based on the calibration compensation set, the laser reflection pulse energy value set, and the ranging value set, and the calibration of the lidar is achieved based on the calibration mapping table.

2. The method as described in claim 1, characterized in that, The step of determining the set of calibration compensation values ​​for the laser scanning point based on the ranging data, the actual distance value, and the set of ranging values ​​includes: Determine the local extreme range laser scanning point based on the ranging data; The angle between the emission paths of other laser points and the emission path of the local extreme laser scanning point is determined based on the ranging data. The true distance value is used as the actual distance value of the local ranging extreme value laser scanning point, and the set of actual distance values ​​of other laser points is determined based on the actual distance value and the included angle. The calibration compensation set is determined based on the set of actual distance values ​​and the set of distance measurements.

3. The method as described in claim 2, characterized in that, The step of determining the local extreme laser scanning point based on the ranging data includes: The target distance values ​​at different times of the laser scanning point are compared based on the distance measurement data. When the target ranging value is detected to decrease and then increase again, the laser scanning point corresponding to the minimum ranging value after the decrease is taken as the local ranging extreme value laser scanning point. If the target ranging value is detected to increase and then increase again, the laser scanning point corresponding to the maximum ranging value after the increase is taken as the local ranging extreme value laser scanning point.

4. The method as described in claim 2, characterized in that, The step of determining the angle between the emission path of other laser points and the emission path of the local ranging extreme value laser scanning point based on the ranging data includes: Other laser points are classified, and the laser scanning points emitted by the transmitter of the local ranging extreme value laser scanning point are classified as the first type of laser scanning points, and the remaining laser scanning points are classified as the second type of laser scanning points. Calculate the horizontal angle between the emission path of the first type of laser scanning point and the emission path of the local extreme laser scanning point based on the ranging data; Calculate the horizontal and vertical angles between the emission path of the second type of laser scanning point and the emission path of the local ranging extreme value laser scanning point based on the ranging data.

5. The method as described in claim 2, characterized in that, The step of determining the set of actual distance values ​​for other laser points based on the actual distance value and the included angle includes: The calculation method is determined based on the local extreme value laser scanning points for ranging. The actual distance value and the included angle are calculated according to the calculation method to obtain a set of actual distance values.

6. The method as described in claim 2, characterized in that, The step of determining the calibration compensation set based on the actual distance value set and the ranging value set includes: Determine the correspondence between distance value elements in the actual distance value set and distance value elements in the distance measurement value set; Based on the correspondence, subtract the corresponding distance value element from each of the ranging value elements to obtain the calibration compensation set.

7. The method as described in claim 1, characterized in that, The step of establishing a calibration mapping table based on the calibration compensation set, the laser reflection pulse energy value set, and the ranging value set includes: The calibration compensation amount, laser reflection pulse energy value, and ranging value of all laser scanning points are determined based on the calibration compensation amount set, the laser reflection pulse energy value set, and the ranging value set. Record the calibration compensation values ​​corresponding to the laser reflection pulse energy values ​​and ranging values ​​of all the laser scanning points to obtain a calibration mapping table.

8. A calibration device for a lidar, characterized in that, The device includes: A transmitting module is used to control the lidar to emit laser scanning points and receive ranging data. The lidar is located on a rotatable turntable, which is located in a room with four reflective walls. The acquisition module is used to acquire the actual distance between the center position of the turntable and the reflective surface; The calculation module is used to obtain the set of laser reflection pulse energy values ​​and the set of distance values ​​of the laser scanning point based on the ranging data; The determination module is used to determine the calibration compensation set of the laser scanning point based on the ranging data, the actual distance value, and the ranging value set; The calibration module is used to establish a calibration mapping table based on the calibration compensation set, the laser reflection pulse energy value set, and the ranging value set, and to calibrate the lidar based on the calibration mapping table.

9. A calibration device for lidar, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the calibration method for a lidar as described in any one of claims 1 to 7.

10. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the calibration method of the lidar as described in any one of claims 1 to 7.

Images