Frequency-modulated continuous-wave lidar calibration method and frequency-modulated continuous-wave lidar system

Abstract

The embodiment of the application provides a frequency-modulated continuous wave laser radar correction method and a frequency-modulated continuous wave laser radar system, the method comprising: acquiring a current scanning angle sequence determined by a current point cloud sequence, the current point cloud sequence being obtained by rotating a mechanical scanning device in response to a control pulse sequence, a sub-time period in a current scanning period, a control pulse in the control pulse sequence and a control driving capability value in a control driving capability sequence corresponding to each other, the control driving capability value in the control driving capability sequence being used for indicating a number of times of rotating the mechanical scanning device in the corresponding sub-time period by the corresponding control pulse; determining a parameter value of an angle change parameter corresponding to each sub-time period based on the current scanning angle sequence; and correcting the control driving capability value corresponding to each sub-time period based on a difference between the parameter value of the angle change parameter corresponding to each sub-time period and a preset parameter value.

Description

Technical Field

[0001] This application relates to the field of lidar, and more specifically, to a frequency-modulated continuous wave lidar correction method and a frequency-modulated continuous wave lidar system. Background Technology

[0002] For FMCW (Frequency Modulated Continuous Wave) lidar, the scanning device used can be a mechanical scanning device. As the equipment is used or its status changes, the scanning device will change, and the scanning frequency will be inconsistent, resulting in non-repeating points in consecutive frames, which will affect the accuracy of target detection.

[0003] Therefore, it can be seen that the frequency-modulated continuous wave lidar system in the relevant technology has the problem of low target detection accuracy due to the presence of non-repeating points in the scanning device in consecutive frames. Summary of the Invention

[0004] This application provides a frequency-modulated continuous wave lidar correction method and a frequency-modulated continuous wave lidar system to at least solve the technical problem of low target detection accuracy in related technologies caused by non-repeating points appearing in consecutive frames of the scanning device.

[0005] According to one aspect of the embodiments of this application, a frequency-modulated continuous wave (FM-CW) lidar correction method is provided. The FM-CW lidar is equipped with a mechanical scanning device. The method includes: acquiring a current scanning angle sequence corresponding to the current scanning period of the mechanical scanning device, wherein the current scanning angle sequence is a scanning angle sequence determined by a current point cloud sequence corresponding to the current scanning period, the current point cloud sequence is obtained by the mechanical scanning device rotating M times in response to a control pulse sequence, the current scanning period is divided into N sub-time periods, the sub-time periods in the N sub-time periods, the control pulses in the control pulse sequence, and the control drive capability values ​​in the control drive capability sequence are in one-to-one correspondence. The control pulses are used to indicate the number of times the mechanical scanning device is rotated within the corresponding sub-time period. M and N are both positive integers greater than or equal to 2, and M ≥ N. Based on the current scanning angle sequence, the parameter value of the angle change parameter corresponding to each of the N sub-time periods is determined. The angle change parameter corresponding to each sub-time period is used to describe the change of the scanning angle of the mechanical scanning device within each sub-time period. Based on the difference between the parameter value of the angle change parameter corresponding to each sub-time period and the preset parameter value, the control drive capability value corresponding to each sub-time period is corrected. The corrected control drive capability sequence is used to regenerate the control pulse sequence for the next scanning cycle of the current scanning cycle.

[0006] According to another aspect of the embodiments of this application, a frequency-modulated continuous wave lidar system is also provided, comprising: a mechanical scanning device and a control component; wherein, the mechanical scanning device is used to rotate M times in response to a control pulse sequence within a current scanning period to obtain a current point cloud sequence, wherein the current scanning period is divided into N sub-time periods, the sub-time periods in the N sub-time periods, the control pulses in the control pulse sequence, and the control drive capability values ​​in the control drive capability sequence correspond one-to-one, the control drive capability values ​​in the control drive capability sequence are used to indicate the number of times the corresponding control pulse controls the mechanical scanning device to rotate within the corresponding sub-time period, M and N are both positive integers greater than or equal to 2, and M≥N; the control component is used to acquire the current scanning angle sequence of the mechanical scanning device corresponding to the current scanning period, wherein... The current scanning angle sequence is a scanning angle sequence determined by the current point cloud sequence. Based on the current scanning angle sequence, parameter values ​​of angle change parameters corresponding to each of the N sub-time periods are determined, wherein the angle change parameters corresponding to each sub-time period are used to describe the change in the scanning angle of the mechanical scanning device within each sub-time period. Based on the difference between the parameter values ​​of the angle change parameters corresponding to each sub-time period and the preset parameter values, the control drive capability value corresponding to each sub-time period is corrected, wherein the corrected control drive capability sequence is used to regenerate the control pulse sequence for the next scanning cycle of the current scanning cycle. The mechanical scanning device is also used to rotate M times in response to the control of the regenerated control pulse sequence in the next scanning cycle of the current scanning cycle.

[0007] This application employs a method of correcting the control drive capability value. It obtains the current scanning angle sequence corresponding to the current scanning cycle of the mechanical scanning device. The current scanning angle sequence is determined by the current point cloud sequence corresponding to the current scanning cycle. The current point cloud sequence is obtained by the mechanical scanning device rotating M times in response to the control pulse sequence. The current scanning cycle is divided into N sub-time periods. Each of the N sub-time periods, the control pulses in the control pulse sequence, and the control drive capability value in the control drive capability sequence corresponds one-to-one. The control drive capability value in the control drive capability sequence indicates the number of times the corresponding control pulse controls the mechanical scanning device to rotate within the corresponding sub-time period. M and N are both positive integers greater than or equal to 2, and M ≥ N. Based on the current scanning angle sequence, the corresponding N sub-time periods are determined. The parameter values ​​of the angle change parameters corresponding to each sub-time period are used to describe the change of the scanning angle of the mechanical scanning device within each sub-time period. Based on the difference between the parameter values ​​of the angle change parameters corresponding to each sub-time period and the preset parameter values, the control drive capability value corresponding to each sub-time period is corrected. The corrected control drive capability sequence is used to regenerate the control pulse sequence for the next scanning cycle of the current scanning cycle. Since the actual rotation angle value is compared with the theoretical value, and the control drive capability value is adjusted based on the comparison result for correction, the technical problem of low target detection accuracy caused by non-repeating points in consecutive frames of the scanning device in the related technology of frequency-modulated continuous wave lidar system can be solved, thereby achieving the technical effect of improving the accuracy of target detection. Attached Figure Description

[0008] Figure 1 This is a schematic diagram illustrating an application scenario of a frequency-modulated continuous wave lidar correction method according to an embodiment of this application;

[0009] Figure 2 This is a schematic flowchart of an optional frequency-modulated continuous wave lidar correction method according to an embodiment of this application;

[0010] Figure 3 This is a schematic diagram of an optional frequency-modulated continuous wave lidar correction method according to an embodiment of this application;

[0011] Figure 4 This is a schematic diagram of another optional frequency-modulated continuous wave lidar correction method according to an embodiment of this application;

[0012] Figure 5 This is a schematic diagram of another optional frequency-modulated continuous wave lidar correction method according to an embodiment of this application;

[0013] Figure 6This is a schematic diagram of another optional frequency-modulated continuous wave lidar correction method according to an embodiment of this application;

[0014] Figure 7 This is a schematic diagram of another optional frequency-modulated continuous wave lidar correction method according to an embodiment of this application;

[0015] Figure 8 This is a structural block diagram of an optional frequency-modulated continuous wave lidar system according to an embodiment of this application;

[0016] Figure 9 This is a computer system architecture block diagram of an optional electronic device according to an embodiment of this application. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0018] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] According to one aspect of the embodiments of this application, a frequency-modulated continuous wave lidar correction method is provided. Optionally, in this embodiment, the above-described frequency-modulated continuous wave lidar correction method may be applied, but is not limited to, to applications such as... Figure 1 The diagram shows a hardware environment including LiDAR 102 and server 104. LiDAR 102 is a mechanical LiDAR. Server 104 can connect to LiDAR 102 via a network and can be used to provide services (e.g., application services) to LiDAR 102 or clients installed on LiDAR 102. A database can be set up on or independently of server 104 to provide data storage services to server 104.

[0020] The aforementioned lidar 102 can be an frequency-modulated continuous wave lidar, which is equipped with a mechanical scanning device. This mechanical scanning device uses a stepper motor and other mechanical control components to control the scanning angle. The aforementioned network can include, but is not limited to, at least one of the following: wired network and wireless network. The aforementioned wired network can include, but is not limited to, at least one of the following: wide area network (WAN), metropolitan area network (MAN), and local area network (LAN). The aforementioned wireless network can include, but is not limited to, at least one of the following: Wi-Fi (Wireless Fidelity) and Bluetooth. The server 104 can be, but is not limited to, a cloud server, a server cluster, or other server types.

[0021] The frequency-modulated continuous wave lidar correction method of this application embodiment can be executed by lidar 102, or it can be jointly executed by lidar 102 and server 104. Alternatively, the lidar 102 can execute the frequency-modulated continuous wave lidar correction method of this application embodiment by a control component mounted thereon.

[0022] Taking the frequency-modulated continuous wave lidar correction method in this embodiment, executed by lidar 102, as an example, Figure 2 This is a schematic flowchart of an optional frequency-modulated continuous wave lidar correction method according to an embodiment of this application, as shown below. Figure 2 As shown, the process of this method may include the following steps:

[0023] Step S202: Obtain the current scanning angle sequence corresponding to the current scanning cycle of the mechanical scanning device. The current scanning angle sequence is determined by the current point cloud sequence corresponding to the current scanning cycle. The current point cloud sequence is obtained by the mechanical scanning device rotating M times in response to the control pulse sequence. The current scanning cycle is divided into N sub-time periods. The sub-time periods in the N sub-time periods, the control pulses in the control pulse sequence, and the control drive capability values ​​in the control drive capability sequence correspond one-to-one. The control drive capability values ​​in the control drive capability sequence are used to indicate the number of times the corresponding control pulse controls the mechanical scanning device to rotate in the corresponding sub-time period. M and N are both positive integers greater than or equal to 2, and M≥N.

[0024] Step S204: Based on the current scanning angle sequence, determine the parameter value of the angle change parameter corresponding to each of the N sub-time periods, wherein the angle change parameter corresponding to each sub-time period is used to describe the change of the scanning angle of the mechanical scanning device in each sub-time period.

[0025] Step S206: Based on the difference between the parameter value of the angle change parameter corresponding to each sub-time period and the preset parameter value, the control drive capability value corresponding to each sub-time period is corrected. The corrected control drive capability sequence is used to regenerate the control pulse sequence for the next scan cycle of the current scan cycle.

[0026] The frequency-modulated continuous wave (FM-CW) lidar correction method in this embodiment can be applied to the lidar field, specifically to scenarios involving the correction of mechanical scanning devices on lidar systems. FM-CW lidar is a radar system that measures the distance, velocity, and angle of a target using frequency-modulated continuous wave laser signals. It is commonly used in automotive, drone, industrial automation, scientific research, and military fields, and boasts advantages such as simple structure, low power consumption, and high precision. The ranging principle of FM-CW lidar is as follows: Figure 3 As shown, the modulated laser emits laser light with a continuously and periodically changing frequency. After the echo is isolated by the isolator, it is split into two laser beams by the coupler. One beam is used as the test optical path and the other is used as the reference optical path. The signal of the test optical path is focused by the focusing system and then acts on the target object. It returns to the circulator along the original path and undergoes optical interference in the coupler. Finally, it is collected by the balanced detector.

[0027] In related technologies, lidar can be categorized into mechanical lidar, semi-solid-state lidar, and solid-state lidar based on the method of beam control. Mechanical lidar, which scans by mechanically rotating a laser and receiver, can achieve 360° omnidirectional scanning. Mechanical lidar offers advantages such as high precision, fast scanning, a small receiving field of view, and the ability to withstand high laser power. However, due to its rotating structure, mechanical lidar is susceptible to mechanical wear during long-term operation, and the scanning frequency may become inconsistent with changes in equipment usage or condition.

[0028] To at least partially address the aforementioned technical problems, in this embodiment, the changes in the scanning angle of the mechanical scanning device can be determined based on its current scanning angle sequence, and compared with the theoretical value of the angle change to correct the control and driving capability of the mechanical scanning device. By correcting the control and driving capability, the radar scanning frequency can be stabilized, the scanning angle can be made more uniform, and thus the success rate of point cloud matching between consecutive frames can be improved.

[0029] Optionally, the mechanical scanning device can be a scanning device that uses a stepper motor or other rotation control component to control the scanning angle. A stepper motor is an electric motor that converts electrical pulse signals into corresponding angular or linear displacement. The stepper motor controls its rotation by controlling a sequence of currents (i.e., electrical pulse signals). For each input pulse signal, the rotor rotates by a fixed angle or moves forward one step. Its output angular or linear displacement is proportional to the number of input pulses, and its rotational speed is proportional to the pulse frequency; therefore, it is also called a pulse motor. Because the rotation angle of a stepper motor strictly corresponds to the number of input pulses, it has extremely high positioning accuracy. However, after prolonged use, the control and drive capability of the stepper motor may deteriorate, causing the rotation angle of each rotation to deviate from the expected value.

[0030] To correct the control and drive capability of the rotation control component, the current scanning angle sequence corresponding to the current scanning cycle of the mechanical scanning device can be obtained. This current scanning angle sequence is determined by the current point cloud sequence corresponding to the current scanning cycle. The current point cloud sequence is obtained by the mechanical scanning device rotating M times in response to the control pulse sequence. That is, the mechanical scanning device rotates a total of M times in the current scanning cycle, obtaining M detection points. The current point cloud sequence indicates the order in which the M detection points are acquired. The scanning angle is calculated based on each detection point to obtain the current scanning angle sequence containing M scanning angles. For example, if there are two control pulses in the control pulse sequence in the current scanning cycle, controlling the mechanical scanning device to rotate 2 times and then 3 times respectively, then the mechanical scanning device will respond to these control pulses by rotating 2 times and then 3 times, for a total of 5 rotations. The current scanning angle sequence contains these 5 scanning angles. Here, the interval between all adjacent angles in the current scanning angle sequence is theoretically equal; that is, theoretically, the angle of each rotation should be equal.

[0031] Furthermore, the current scanning cycle can be divided into N sub-time periods. Each of these N sub-time periods corresponds to a sub-time period, a control pulse in the control pulse sequence, and a control drive capability value in the control drive capability sequence. The control drive capability value in the control drive capability sequence indicates the number of times the corresponding control pulse controls the mechanical scanning device to rotate within the corresponding sub-time period. M and N are both positive integers greater than or equal to 2, and M ≥ N. Here, each sub-time period corresponds to one control pulse. For example, if there are two control pulses in the control pulse sequence within the current scanning cycle, controlling the mechanical scanning device to rotate 2 times and 3 times respectively, then there are two sub-time periods, i.e., N is 2. The first sub-time period corresponds to the first control pulse, in which the mechanical scanning device rotates 2 times in response to the first control pulse, resulting in 2 scanning angles. The second sub-time period corresponds to the second control pulse, in which the motor rotates 3 times in response to the second control pulse, resulting in 3 scanning angles.

[0032] After obtaining the current scanning angle sequence, the parameter values ​​of the angle change parameters corresponding to each of the N sub-time periods can be determined based on the current scanning angle sequence. The angle change parameters corresponding to each sub-time period describe the change in the scanning angle of the mechanical scanning device within each sub-time period.

[0033] After determining the parameter values ​​of the angle change parameters corresponding to each sub-time period, the control drive capability value corresponding to each sub-time period can be corrected based on the difference between the parameter values ​​and the preset parameter values. Here, the preset parameter values ​​are the theoretical parameter values ​​of the angle change parameters, and each sub-time period has its corresponding preset parameter value. For example, within a certain sub-time period, if the parameter value of the angle change parameter corresponding to that sub-time period is greater than the preset parameter value, the control drive capability value can be adjusted downwards accordingly; if the parameter value of the angle change parameter corresponding to that sub-time period is less than the preset parameter value, the control drive capability value can be adjusted upwards accordingly to correct the control drive capability. Here, the corrected control drive capability sequence can be used to regenerate the control pulse sequence for the next scan cycle of the current scan cycle.

[0034] For example, such as Figure 4 As shown, Figure 4 To avoid the potential issues that might arise from not calibrating the motor, the resulting point cloud will exhibit uneven distribution of scan line points, with non-repeating points appearing between consecutive frames. This uneven distribution of probe points in the point cloud can lead to missed detections in practical applications, resulting in inaccurate ranging of critical objects. The point cloud effect after motor calibration is as follows: Figure 5 As shown, the detection points in the visible point cloud are evenly distributed, thus solving the aforementioned problem.

[0035] The embodiments provided in this application obtain a current scanning angle sequence corresponding to the current scanning cycle of the mechanical scanning device. This current scanning angle sequence is determined by a current point cloud sequence corresponding to the current scanning cycle. The current point cloud sequence is obtained by the mechanical scanning device rotating M times in response to a control pulse sequence. The current scanning cycle is divided into N sub-time periods. Each of the N sub-time periods, the control pulses in the control pulse sequence, and the control drive capability values ​​in the control drive capability sequence correspond one-to-one. The control drive capability values ​​in the control drive capability sequence indicate the number of times the corresponding control pulse controls the mechanical scanning device to rotate within the corresponding sub-time period. M and N are both positive integers greater than or equal to 2, and M ≥ N. Given the current scanning angle sequence, the parameter values ​​of the angle change parameters corresponding to each of the N sub-time periods are determined. These angle change parameters describe the changes in the scanning angle of the mechanical scanning device within each sub-time period. Based on the difference between the parameter values ​​of the angle change parameters corresponding to each sub-time period and the preset parameter values, the control drive capability value corresponding to each sub-time period is corrected. The corrected control drive capability sequence is used to regenerate the control pulse sequence for the next scanning cycle of the current scanning cycle. This solves the technical problem of low target detection accuracy in frequency-modulated continuous wave lidar systems due to non-repeating points appearing in consecutive frames of the scanning device, thus improving the accuracy of target detection.

[0036] In an exemplary embodiment, determining the parameter value of the angle change parameter corresponding to each of the N sub-time periods based on the current scanning angle sequence includes: determining the angle difference between the last scanning angle and the first scanning angle in each sub-time period in the current scanning angle sequence as the parameter value of the angle change parameter corresponding to each sub-time period.

[0037] To determine the parameter value of the angle change parameter corresponding to each sub-time period, the angle difference between the last scan angle and the first scan angle in each sub-time period can be determined as the parameter value of the angle change parameter corresponding to each sub-time period.

[0038] For example, in the current scanning angle sequence, there are seven scanning angles: angle 1, angle 2, angle 3, angle 4, angle 5, angle 6, and angle 7. Angles 1 and 2 are in the first sub-time period, angles 3, 4, and 5 are in the second sub-time period, and angles 6 and 7 are in the third sub-time period. Here, the parameter value for the angle change parameter corresponding to the first sub-time period is the angle difference between angle 2 and angle 1; the parameter value for the angle change parameter corresponding to the second sub-time period is the angle difference between angle 5 and angle 3; and the parameter value for the angle change parameter corresponding to the third sub-time period is the angle difference between angle 7 and angle 6.

[0039] In this embodiment, the angle difference between the last scanning angle and the first scanning angle in each sub-time period is determined as the parameter value of the angle change parameter corresponding to each sub-time period. This parameter value can be compared with the theoretical value to correct the control drive capability value and improve the accuracy of target detection.

[0040] In an exemplary embodiment, the control drive capability value corresponding to each sub-time period is corrected based on the difference between the parameter value of the angle change parameter corresponding to each sub-time period and the preset parameter value. This includes: performing the following correction operation on each sub-time period as the current sub-time period to obtain a corrected control drive capability sequence, wherein the parameter value of the angle change parameter corresponding to the current sub-time period is the current parameter value, and the control drive capability value corresponding to the current sub-time period in the control drive capability sequence is the current control drive capability value: if the current parameter value is greater than the preset parameter value, the current control drive capability value is decreased; if the current parameter value is less than the preset parameter value, the current control drive capability value is increased.

[0041] To correct the control drive capability value, each sub-time period can be sequentially taken as the current time period, and the correction operation can be performed on the control drive capability value corresponding to each current time period to obtain the corrected control drive capability sequence. Here, the parameter value of the angle change parameter corresponding to the current sub-time period is the current parameter value, and the control drive capability value in the control drive capability sequence corresponding to the current sub-time period is the current control drive capability value.

[0042] In this embodiment, there are two correction operations depending on the magnitude of the current parameter value and the preset parameter value: if the current parameter value is greater than the preset parameter value, the current control drive capability value is reduced; if the current parameter value is less than the preset parameter value, the current control drive capability value is increased.

[0043] For example, taking a stepper motor as an example, there are M scanning angles in the current scanning angle sequence, which is {ang_1, ang_2, ang_3,..., ang_M}. There are N control pulses in the corresponding control pulse sequence, which is {m1, m2,..., mN}, and the control driving ability sequence corresponding to the control pulse sequence is {F1, F2,..., FN}. Among them, the relationship between the number of control pulses in the control pulse sequence and the number of scanning angles is shown in formula (1):

[0044] m1 + m2 + m3 +... + mN = M (1)

[0045] Here, the value of each control pulse in the control pulse sequence is a constant, and its value corresponds to the number of times the motor rotates indicated by the control pulse. For example, if the first control pulse m1 indicates that the motor rotates 2 times and the second control pulse m2 indicates that the motor rotates 3 times, then the value of m1 is 2, and there are 2 scanning angles, ang_1 and ang_2, in the first sub-time period; the value of m2 is 3, and there are 3 scanning angles, ang_3, ang_4, and ang_5, in the second sub-time period. The sum of the values of all control pulses is equal to the number of scanning angles.

[0046] After that, the parameter values of the angle change parameters corresponding to each sub-time period can be calculated to obtain the parameter value sequence of the angle change parameters {S1, S2,..., SN}, where S1 = ang_m1 - ang_1 (that is, the angle value of the m1-th scanning angle minus the angle value of the first scanning angle), S2 = ang_(m1 + m2) - ang_(m1 + 1) (that is, the angle value of the m1 + m2-th scanning angle minus the angle value of the m1 + 1-th scanning angle), and the other parameter values of the parameter value sequence of the angle change parameters can be deduced by analogy.

[0047] By comparing the size of the parameter value sequence S of the angle change parameter with the preset parameter value ST, the control driving ability sequence F corresponding to the control pulse m sequence can be adjusted to obtain the corrected control driving ability sequence. For example, if S1 > ST, then F1 can be correspondingly reduced. Similarly, if SN < ST, then FN can be correspondingly increased.

[0048] It should be noted that the corresponding relationship between the detection point number and the scanning angle can be a linear relationship (a straight line with a constant slope), as Figure 6 shown, and the corresponding relationship diagram as Figure 7 shown is likely to occur during actual use. Correcting the control driving ability is to correct the corresponding relationship as Figure 7 shown to be closer to the corresponding relationship as Figure 6 shown.

[0049] In this embodiment, by adjusting the current control drive capability value based on the relationship between the current parameter value and the preset parameter value, a corrected control drive capability sequence can be obtained, thereby achieving the correction of the control drive capability value.

[0050] In one exemplary embodiment, when the current parameter value is greater than a preset parameter value, decreasing the current control drive capability value includes: when the current parameter value is greater than the preset parameter value, adjusting the current control drive capability value by the adjustment value corresponding to the current parameter difference according to a preset correspondence between parameter difference and adjustment value, wherein the current parameter difference is the absolute value of the parameter difference between the current parameter value and the preset parameter value; when the current parameter value is less than the preset parameter value, increasing the current control drive capability value includes: when the current parameter value is less than the preset parameter value, adjusting the current control drive capability value by the adjustment value corresponding to the current parameter difference according to a preset correspondence between parameter difference and adjustment value, wherein the current parameter difference is the absolute value of the parameter difference between the current parameter value and the preset parameter value.

[0051] In this embodiment, after determining the adjustment direction of the current control drive capability value based on the relationship between the current parameter value and the preset parameter value, the specific value of the current control drive capability value adjustment can also be determined based on the current parameter difference. Here, the current parameter difference is the absolute value of the parameter difference between the current parameter value and the preset parameter value.

[0052] When the current parameter value is greater than the preset parameter value, the current control drive capability value is reduced by the adjustment value corresponding to the current parameter difference, according to the preset correspondence between parameter difference and adjustment value. When the current parameter value is less than the preset parameter value, the current control drive capability value is increased by the adjustment value corresponding to the current parameter difference, according to the preset correspondence between parameter difference and adjustment value. The preset correspondence between parameter difference and adjustment value can be determined in advance through experiments. Its form can be a functional relationship between parameter difference and adjustment value, a table containing each parameter difference and its corresponding adjustment value, or a calculation formula for obtaining the adjustment value from the parameter difference. In this embodiment, there is no limitation on this.

[0053] This embodiment allows the control drive capability value to be adjusted to a suitable value based on the correspondence between preset parameter differences and adjustment values, thereby improving the rationality and efficiency of drive capability adjustment.

[0054] In an exemplary embodiment, obtaining the current scanning angle sequence corresponding to the current scanning cycle of the mechanical scanning device includes: generating the current scanning angle sequence based on the modulation ranging number of each detection point in the current point cloud sequence and the angle code disk information of each detection point, wherein the modulation ranging number of each detection point is used to indicate the order of scanning to each detection point, and the angle code disk information of each detection point is used to indicate the scanning angle corresponding to each detection point.

[0055] To obtain the current scanning angle sequence, it can be generated based on the modulation ranging number of each detection point in the current point cloud sequence and the angle code information of each detection point. The modulation ranging number of each detection point indicates the order in which each detection point is scanned, and the angle code information of each detection point indicates the scanning angle corresponding to that detection point. For example, the first scanning angle in the current scanning angle sequence, i.e., the scanning angle of the first detection point in the detection point cloud sequence, has a modulation ranging number of 1, and its angle code information is the angle value of that scanning angle; the nth scanning angle in the current scanning angle sequence, i.e., the scanning angle of the nth detection point in the detection point cloud sequence, has a modulation ranging number of n, and its angle code information is the angle value of that scanning angle.

[0056] In this embodiment, the current scanning angle sequence is generated based on the modulation ranging number of each detection point and the angle code disk information of each detection point. This ensures the accuracy of the current scanning angle sequence generation and improves the accuracy of the scanning device calibration.

[0057] In one exemplary embodiment, obtaining the current scanning angle sequence corresponding to the current scanning cycle of the mechanical scanning device further includes: obtaining the detection points scanned by the mechanical scanning device in the current scanning cycle from the mechanical scanning device through an external module of the mechanical scanning device, thereby obtaining the current point cloud sequence.

[0058] To obtain the current scanning angle sequence, an external module can be attached to the mechanical scanning device. This external module can collect the modulation ranging number and angle code disk information of each detection point scanned by the mechanical scanning device in the current scanning cycle, and use them to generate a detection point cloud sequence.

[0059] It should be noted that the aforementioned external module is only used to collect information from the detection points of the mechanical scanning device; adjustments to the mechanical scanning device are made by the mechanical scanning device itself.

[0060] In this embodiment, the current point cloud sequence is acquired through an external module of the mechanical scanning device, which improves the flexibility of point cloud sequence acquisition. At the same time, it can also reduce the hardware and software requirements of the frequency-modulated continuous wave lidar and reduce the cost of the frequency-modulated continuous wave lidar.

[0061] In an exemplary embodiment, after determining the parameter value of the angle change parameter corresponding to each of the N sub-time periods based on the current scanning angle sequence, the method further includes: generating an abnormal prompt message if there is a parameter value greater than or equal to a preset parameter threshold among the parameter values ​​of the angle change parameter corresponding to each sub-time period, wherein the abnormal prompt message is used to provide an abnormal reminder to the mechanical scanning device.

[0062] To ensure accurate target detection, if the deviation of the mechanical scanning device is too large—that is, if any parameter value in the angle change parameters corresponding to each sub-time period is greater than or equal to a preset parameter threshold—calibrating the LiDAR may not solve the problem. Therefore, an anomaly alert can be generated to relevant personnel. This anomaly alert is used to indicate anomalies in the mechanical scanning device, and the preset parameter threshold can be set empirically, representing the maximum range of calibration capability for the LiDAR.

[0063] Here, there are various ways to provide the above-mentioned abnormal prompt information. For example, it can be done through the sound device on the lidar, or it can output a text-formatted abnormal prompt information at the same time as the lidar outputs the scanning results. In this embodiment, there is no limitation on this.

[0064] In this embodiment, when the deviation of the mechanical scanning device is too large and the correction result cannot be guaranteed, an abnormal prompt message is generated to remind users of the error, which can improve the reliability of the scanning results and enhance the user experience.

[0065] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0066] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM (Read-Only Memory) / RAM (Random Access Memory), magnetic disk, optical disk), and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of this application.

[0067] According to another aspect of the embodiments of this application, a frequency-modulated continuous wave lidar system is also provided. This frequency-modulated continuous wave lidar system can be used to implement the frequency-modulated continuous wave lidar correction method provided in the above embodiments, and details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0068] Figure 8 This is a structural block diagram of an optional frequency-modulated continuous wave lidar system according to an embodiment of this application, such as... Figure 8 As shown, the frequency-modulated continuous wave lidar system includes: a mechanical scanning device 802 and a control component 804, wherein,

[0069] The mechanical scanning device 802 is used to rotate M times in response to the control pulse sequence within the current scanning cycle to obtain the current point cloud sequence. The current scanning cycle is divided into N sub-time periods. The sub-time periods, control pulses in the control pulse sequence, and control drive capability values ​​in the control drive capability sequence correspond one-to-one. The control drive capability values ​​in the control drive capability sequence are used to indicate the number of times the corresponding control pulse controls the mechanical scanning device 802 to rotate within the corresponding sub-time period. M and N are both positive integers greater than or equal to 2, and M≥N.

[0070] The control unit 804 is used to acquire the current scanning angle sequence of the mechanical scanning device 802 corresponding to the current scanning cycle, wherein the current scanning angle sequence is the scanning angle sequence determined by the current point cloud sequence; based on the current scanning angle sequence, it determines the parameter value of the angle change parameter corresponding to each of the N sub-time periods, wherein the angle change parameter corresponding to each sub-time period is used to describe the change of the scanning angle of the mechanical scanning device 802 in each sub-time period; based on the difference between the parameter value of the angle change parameter corresponding to each sub-time period and the preset parameter value, it corrects the control drive capability value corresponding to each sub-time period, wherein the corrected control drive capability sequence is used to regenerate the control pulse sequence for the next scanning cycle of the current scanning cycle;

[0071] The mechanical scanning device 802 is also used to rotate M times in response to the control of a newly generated control pulse sequence in the next scan cycle of the current scan cycle.

[0072] It should be noted that the control component 804 in this embodiment can be used to execute steps S202, S204 and S206 in the foregoing embodiment.

[0073] The embodiments provided in this application obtain a current scanning angle sequence corresponding to the current scanning cycle of the mechanical scanning device. This current scanning angle sequence is determined by a current point cloud sequence corresponding to the current scanning cycle. The current point cloud sequence is obtained by the mechanical scanning device rotating M times in response to a control pulse sequence. The current scanning cycle is divided into N sub-time periods. Each of the N sub-time periods, the control pulses in the control pulse sequence, and the control drive capability values ​​in the control drive capability sequence correspond one-to-one. The control drive capability values ​​in the control drive capability sequence indicate the number of times the corresponding control pulse controls the mechanical scanning device to rotate within the corresponding sub-time period. M and N are both positive integers greater than or equal to 2, and M ≥ N. Given the current scanning angle sequence, the parameter values ​​of the angle change parameters corresponding to each of the N sub-time periods are determined. These angle change parameters describe the changes in the scanning angle of the mechanical scanning device within each sub-time period. Based on the difference between the parameter values ​​of the angle change parameters corresponding to each sub-time period and the preset parameter values, the control drive capability value corresponding to each sub-time period is corrected. The corrected control drive capability sequence is used to regenerate the control pulse sequence for the next scanning cycle of the current scanning cycle. This solves the technical problem of low target detection accuracy in frequency-modulated continuous wave lidar systems due to non-repeating points appearing in consecutive frames of the scanning device, thus improving the accuracy of target detection.

[0074] In one exemplary embodiment, the control component is further configured to determine the angle difference between the last scanning angle in each sub-time period and the first scanning angle in each sub-time period in the current scanning angle sequence as the parameter value of the angle change parameter corresponding to each sub-time period.

[0075] In an exemplary embodiment, the control unit is further configured to perform the following correction operation on each sub-time period as the current sub-time period to obtain a corrected control drive capability sequence, wherein the parameter value of the angle change parameter corresponding to the current sub-time period is the current parameter value, and the control drive capability value corresponding to the current sub-time period in the control drive capability sequence is the current control drive capability value: if the current parameter value is greater than a preset parameter value, the current control drive capability value is decreased; if the current parameter value is less than a preset parameter value, the current control drive capability value is increased.

[0076] In one exemplary embodiment, the control unit is further configured to, when the current parameter value is greater than a preset parameter value, adjust the current control drive capability value by decreasing the adjustment value corresponding to the current parameter difference according to a preset correspondence between parameter difference and adjustment value, wherein the current parameter difference is the absolute value of the parameter difference between the current parameter value and the preset parameter value; and when the current parameter value is less than the preset parameter value, adjust the current control drive capability value by increasing the adjustment value corresponding to the current parameter difference according to a preset correspondence between parameter difference and adjustment value, wherein the current parameter difference is the absolute value of the parameter difference between the current parameter value and the preset parameter value.

[0077] In one exemplary embodiment, the control component is further configured to generate a current scanning angle sequence based on the modulation ranging number of each detection point in the current point cloud sequence and the angle code information of each detection point, wherein the modulation ranging number of each detection point is used to indicate the order of scanning to each detection point, and the angle code information of each detection point is used to indicate the scanning angle corresponding to each detection point.

[0078] In one exemplary embodiment, the frequency modulated continuous wave lidar system further includes an external module for acquiring the detection points scanned by the mechanical scanning device during the current scanning cycle, thereby obtaining a detection point cloud sequence.

[0079] In an exemplary embodiment, the control unit 804 is further configured to, after determining the parameter value of the angle change parameter corresponding to each of the N sub-time periods based on the current scanning angle sequence, generate an abnormal prompt message if there is a parameter value greater than or equal to a preset parameter threshold among the parameter values ​​of the angle change parameter corresponding to each sub-time period, wherein the abnormal prompt message is used to provide an abnormal reminder to the mechanical scanning device.

[0080] It should be noted that the above modules can be implemented by software or hardware. For the latter, they can be implemented in the following ways, but are not limited to: all the above modules are located in the same processor; or, the above modules are located in different processors in any combination.

[0081] According to another aspect of the embodiments of this application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein the program executes the steps in any of the above method embodiments when it is run.

[0082] In one exemplary embodiment, the aforementioned computer-readable storage medium may include, but is not limited to, various media capable of storing computer programs, such as USB flash drives, ROMs, RAMs, portable hard drives, magnetic disks, or optical disks.

[0083] According to another aspect of the embodiments of this application, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor is configured to perform the steps of any of the method embodiments described above via the computer program. In an exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0084] Specific examples in this embodiment can be found in the examples described in the above embodiments and exemplary implementations, and will not be repeated here.

[0085] According to another aspect of the embodiments of this application, a computer program product is also provided, comprising a computer program / instructions containing program code for performing the methods shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via a communication section 909, and / or installed from a removable medium 911. When the computer program is executed by a central processing unit 901, it performs various functions provided in the embodiments of this application. The sequence numbers of the embodiments of this application above are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0086] Figure 9 A schematic block diagram of a computer system architecture for implementing embodiments of the present application is shown. Figure 9As shown, the computer system 900 includes a CPU (Central Processing Unit) 901, which can perform various appropriate actions and processes based on programs stored in ROM 902 or programs loaded into RAM 903 from storage section 908. Random access memory 903 also stores various programs and data required for system operation. The CPU 901, ROM 902, and RAM 903 are interconnected via bus 904. An I / O (Input / Output) interface 905 is also connected to bus 904.

[0087] The following components are connected to I / O interface 905: input section 906 including keyboard, mouse, etc.; output section 907 including CRT (Cathode Ray Tube), LCD (Liquid Crystal Display), etc., and speakers, etc.; storage section 908 including hard disk, etc.; and communication section 909 including network interface card, modem, etc. Communication section 909 performs communication processing via a network such as the Internet. Drive 910 is also connected to I / O interface 905 as needed. Removable media 911, such as disk, optical disk, magneto-optical disk, semiconductor memory, etc., are installed on drive 910 as needed so that computer programs read from them can be installed into storage section 908 as needed.

[0088] Specifically, according to embodiments of this application, the processes described in the various method flowcharts can be implemented as computer software programs. For example, embodiments of 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 communication section 909, and / or installed from removable medium 911. When the computer program is executed by central processing unit 901, it performs various functions defined in the system of this application.

[0089] It should be noted that, Figure 9 The computer system 900 of the electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0090] Obviously, those skilled in the art should understand that the modules or steps of this application described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, this application is not limited to any particular combination of hardware and software.

[0091] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A frequency-modulated continuous wave lidar calibration method, characterized by, The frequency-modulated continuous wave lidar is equipped with a mechanical scanning device, and the method includes: Obtain the current scanning angle sequence corresponding to the current scanning cycle of the mechanical scanning device. The current scanning angle sequence is determined by the current point cloud sequence corresponding to the current scanning cycle. The current point cloud sequence is obtained by the mechanical scanning device rotating M times in response to the control pulse sequence. The current scanning cycle is divided into N sub-time periods. The sub-time periods in the N sub-time periods, the control pulses in the control pulse sequence, and the control drive capability values ​​in the control drive capability sequence are in one-to-one correspondence. The control drive capability values ​​in the control drive capability sequence are used to indicate the number of times the corresponding control pulse controls the mechanical scanning device to rotate within the corresponding sub-time period. M and N are both positive integers greater than or equal to 2, and M≥N. Based on the current scanning angle sequence, determine the parameter value of the angle change parameter corresponding to each of the N sub-time periods, wherein the angle change parameter corresponding to each sub-time period is used to describe the change of the scanning angle of the mechanical scanning device in each sub-time period; Based on the difference between the parameter value of the angle change parameter corresponding to each sub-time period and the preset parameter value, the control drive capability value corresponding to each sub-time period is corrected, wherein the corrected control drive capability sequence is used to regenerate the control pulse sequence for the next scan cycle of the current scan cycle.

2. The method according to claim 1, characterized in that, The step of determining the parameter value of the angle change parameter corresponding to each of the N sub-time periods based on the current scanning angle sequence includes: The angle difference between the last scanning angle and the first scanning angle in each sub-time period in the current scanning angle sequence is determined as the parameter value of the angle change parameter corresponding to each sub-time period.

3. The method according to claim 1, characterized in that, The step of correcting the control drive capability value corresponding to each sub-time period based on the difference between the parameter value of the angle change parameter corresponding to each sub-time period and the preset parameter value includes: Each sub-time period is treated as the current sub-time period, and the following correction operation is performed to obtain the corrected control drive capability sequence, wherein the parameter value of the angle change parameter corresponding to the current sub-time period is the current parameter value, and the control drive capability value corresponding to the current sub-time period in the control drive capability sequence is the current control drive capability value: If the current parameter value is greater than the preset parameter value, the current control drive capability value is reduced. If the current parameter value is less than the preset parameter value, the current control drive capability value is increased.

4. The method according to claim 3, characterized in that, The step of reducing the current control drive capability value when the current parameter value is greater than the preset parameter value includes: when the current parameter value is greater than the preset parameter value, adjusting the current control drive capability value to a value corresponding to the current parameter difference according to a preset correspondence between parameter difference and adjustment value, wherein the current parameter difference is the absolute value of the parameter difference between the current parameter value and the preset parameter value; The step of increasing the current control drive capability value when the current parameter value is less than the preset parameter value includes: when the current parameter value is less than the preset parameter value, increasing the current control drive capability value by an adjustment value corresponding to the current parameter difference according to a preset correspondence between parameter difference and adjustment value, wherein the current parameter difference is the absolute value of the parameter difference between the current parameter value and the preset parameter value.

5. The method according to claim 1, characterized in that, The step of obtaining the current scanning angle sequence corresponding to the current scanning cycle of the mechanical scanning device includes: The current scanning angle sequence is generated based on the modulation ranging number of each detection point in the current point cloud sequence and the angle code information of each detection point by the mechanical scanning device. The modulation ranging number of each detection point is used to indicate the order in which each detection point is scanned, and the angle code information of each detection point is used to indicate the scanning angle corresponding to each detection point.

6. The method according to claim 5, characterized in that, The step of obtaining the current scanning angle sequence corresponding to the current scanning cycle of the mechanical scanning device further includes: The current point cloud sequence is obtained by acquiring the detection points scanned by the mechanical scanning device within the current scanning cycle through an external module of the mechanical scanning device.

7. The method according to any one of claims 1 to 6, characterized in that, After determining the parameter values ​​of the angle change parameters corresponding to each of the N sub-time periods based on the current scanning angle sequence, the method further includes: If any parameter value among the angle change parameters corresponding to each sub-time period is greater than or equal to a preset parameter threshold, an abnormality prompt message is generated. The abnormality prompt message is used to provide an abnormality reminder to the mechanical scanning device.

8. A frequency-modulated continuous wave lidar system, characterized in that, include: Mechanical scanning device and control components; wherein, The mechanical scanning device is used to rotate M times in response to a control pulse sequence within the current scanning cycle to obtain the current point cloud sequence. The current scanning cycle is divided into N sub-time periods. The sub-time periods, control pulses in the control pulse sequence, and control drive capability values ​​in the control drive capability sequence correspond one-to-one. The control drive capability values ​​in the control drive capability sequence are used to indicate the number of times the corresponding control pulse controls the mechanical scanning device to rotate within the corresponding sub-time period. M and N are both positive integers greater than or equal to 2, and M≥N. The control unit is configured to acquire the current scanning angle sequence corresponding to the mechanical scanning device and the current scanning cycle, wherein the current scanning angle sequence is a scanning angle sequence determined by the current point cloud sequence; based on the current scanning angle sequence, determine the parameter value of the angle change parameter corresponding to each of the N sub-time periods, wherein the angle change parameter corresponding to each sub-time period is used to describe the change of the scanning angle of the mechanical scanning device in each sub-time period; based on the difference between the parameter value of the angle change parameter corresponding to each sub-time period and the preset parameter value, correct the control drive capability value corresponding to each sub-time period, wherein the corrected control drive capability sequence is used to regenerate the control pulse sequence for the next scanning cycle of the current scanning cycle; The mechanical scanning device is further configured to rotate M times in response to the control of the regenerated control pulse sequence in the next scanning cycle of the current scanning cycle.

9. The system according to claim 8, characterized in that, The control component is further configured to determine the angle difference between the last scanning angle and the first scanning angle in each sub-time period in the current scanning angle sequence as the parameter value of the angle change parameter corresponding to each sub-time period.

10. The system according to claim 8 or 9, characterized in that, The control unit is further configured to perform the following correction operation on each sub-time period as the current sub-time period to obtain the corrected control drive capability sequence, wherein the parameter value of the angle change parameter corresponding to the current sub-time period is the current parameter value, and the control drive capability value corresponding to the current sub-time period in the control drive capability sequence is the current control drive capability value: if the current parameter value is greater than the preset parameter value, the current control drive capability value is decreased; if the current parameter value is less than the preset parameter value, the current control drive capability value is increased.

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