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

Abstract

This application provides a frequency-modulated continuous wave (FM-CW) lidar calibration method and a FM-CW lidar system. The method includes: when calibrating a scanning device for an FM-CW lidar, controlling the scanning device to point towards a preset fiber optic monitoring link; transmitting a detection signal to the fiber optic monitoring link through the scanning device, and determining the actual detection distance corresponding to the fiber optic monitoring link based on the echo signal from the fiber optic monitoring link; and calibrating specified device parameters of the scanning device based on the actual detection distance and the preset detection distance corresponding to the fiber optic monitoring link to obtain the calibrated specified device parameters. This application solves the problems of high structural complexity and high cost of FM-CW lidar calibration methods in related technologies, thereby achieving the technical effect of reducing the structural complexity and cost of lidar.

Description

Technical Field

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

[0002] In FMCW (Frequency Modulated Continuous Wave) lidar, the laser linewidth and DDS (Direct Digital Synthesis) hardware circuitry are affected by different environments, leading to a decrease in measurement accuracy. Related technologies can employ additional optical paths for distance calculation, and then use the calculated distance results to calibrate the relevant devices.

[0003] However, adding extra optical paths not only increases the structural complexity of lidar but also raises its cost, making it difficult to widely apply in multi-laser systems. Therefore, the frequency-modulated continuous wave lidar correction method in related technologies suffers from both high structural complexity and high cost. 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 problems of high structural complexity and high cost of lidar in the frequency-modulated continuous wave lidar correction methods of related technologies.

[0005] According to one aspect of the embodiments of this application, a frequency-modulated continuous wave lidar calibration method is provided, comprising: when a scanning device of the frequency-modulated continuous wave lidar is to be calibrated, controlling the scanning device to point to a preset fiber optic monitoring link; transmitting a detection signal to the fiber optic monitoring link through the scanning device, and determining an actual detection distance corresponding to the fiber optic monitoring link based on the echo signal of the fiber optic monitoring link; and calibrating specified device parameters of the scanning device based on the actual detection distance and the preset detection distance corresponding to the fiber optic monitoring link to obtain the calibrated specified device parameters.

[0006] According to another aspect of the embodiments of this application, a frequency-modulated continuous wave lidar system is also provided, comprising: a scanning component, an optical fiber monitoring link, and a control component, wherein the control component is configured to: control the scanning device to point towards the optical fiber monitoring link when the scanning device is to be calibrated; control the scanning device to transmit a detection signal to the optical fiber monitoring link, and determine the actual detection distance corresponding to the optical fiber monitoring link based on the echo signal of the optical fiber monitoring link; calibrate specified device parameters of the scanning device based on the actual detection distance and a preset detection distance corresponding to the optical fiber monitoring link, to obtain the calibrated specified device parameters; the scanning component is configured to: respond to the control of the control component to point towards the optical fiber monitoring link; transmit the detection signal to the optical fiber monitoring link, and receive the echo signal of the optical fiber monitoring link.

[0007] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, wherein a computer program is stored in the computer program, and the computer program is configured to perform the steps in any of the above method embodiments when it is run.

[0008] According to another aspect of the embodiments of this application, a computer program product or computer program is provided, the computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, causing the computer device to perform the steps in any of the method embodiments described above.

[0009] According to another aspect of the embodiments of this application, an electronic device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to perform the steps of any of the above method embodiments through the computer program.

[0010] This application proposes a method that adds a reflection loop at a fixed location inside the device. When calibrating a scanning device for a frequency-modulated continuous wave lidar, the scanning device is controlled to point towards a preset fiber optic monitoring link. The scanning device then transmits a detection signal to the fiber optic monitoring link to obtain its echo signal. Based on the echo signal, the actual detection distance corresponding to the fiber optic monitoring link can be determined by analyzing the frequency data. By comparing the actual detection distance with the preset detection distance corresponding to the fiber optic monitoring link, the current value of the calibration parameters can be calculated to calibrate the specified device parameters of the scanning device, thereby obtaining the calibrated specified device parameters. Since a fixed reflection loop is set inside the device, which is the fiber optic monitoring link (e.g., a section of optical fiber), complex optical path components can be saved. This not only reduces the structural complexity of the lidar but also reduces the calibration cost, thus solving the technical problems of high structural complexity and high cost of lidar in related frequency-modulated continuous wave lidar calibration methods. Attached Figure Description

[0011] 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;

[0012] Figure 2 This is a schematic flowchart of an optional frequency-modulated continuous wave lidar correction method according to an embodiment of this application;

[0013] Figure 3 This is a schematic diagram of an optional frequency-modulated continuous wave lidar correction method according to an embodiment of this application;

[0014] Figure 4 This is a schematic diagram of another optional frequency-modulated continuous wave lidar correction method according to an embodiment of this application;

[0015] Figure 5 This is a structural block diagram of an optional frequency-modulated continuous wave lidar system according to an embodiment of this application;

[0016] Figure 6 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 scanning control method for a lidar is provided. Optionally, in this embodiment, the above-described lidar scanning control method may be applied, but is not limited to, to applications such as... Figure 1 The hardware environment shown includes LiDAR 102 and server 104. Server 104 can be connected to LiDAR 102 via a network and can be used to provide services (e.g., application services) to LiDAR 102 or terminal devices associated with LiDAR 102. A database can be set up on or independently of server 104 to provide data storage services for server 104.

[0020] The aforementioned network may include, but is not limited to, at least one of the following: wired network and wireless network. The aforementioned wired network may 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 may include, but is not limited to, at least one of the following: Wi-Fi (Wireless Fidelity) and Bluetooth. The LiDAR 102 may be, but is not limited to, a mechanical LiDAR, a semi-solid-state LiDAR, or a solid-state LiDAR. The server 104 may 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 executed jointly by lidar 102 and server 104. Taking the frequency-modulated continuous wave lidar correction method of 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:

[0022] Step S202: When the scanning device of the frequency modulated continuous wave lidar is to be calibrated, control the scanning device to point to the preset fiber optic monitoring link.

[0023] Step S204: A detection signal is transmitted to the fiber optic monitoring link through a scanning device, and the actual detection distance corresponding to the fiber optic monitoring link is determined based on the echo signal of the fiber optic monitoring link.

[0024] Step S206: Based on the actual detection distance and the preset detection distance corresponding to the fiber optic monitoring link, the specified device parameters of the scanning device are corrected to obtain the corrected specified device parameters.

[0025] The frequency-modulated continuous wave (FMCW) lidar correction method described in this application can be applied to the lidar field, specifically to scenarios involving area detection using FMCW lidar. FMCW lidar is a lidar system utilizing frequency-modulated continuous wave technology. Its core principle involves transmitting and receiving continuous laser beams, interfering the echo signal with the local oscillator signal, and using frequency mixing detection technology to measure the frequency difference between the transmitted and received signals. Based on this frequency difference, information such as the target's distance and velocity is calculated. Factors affecting the beat frequency information between the echo signal and the local oscillator signal include the lidar's transmit power, receive gain, environmental factors, and the light source. In the design of frequency-modulated continuous wave lidar, performance factors such as transmit power, receive gain, and the light source are considered. However, under different environments (e.g., different ambient temperatures), the laser's linewidth and the DDS hardware circuitry of the FMCW lidar are affected, leading to a decrease in measurement accuracy.

[0026] In related technologies, an additional optical path (monitoring optical path) is needed for distance calculation in order to calibrate the relevant components of the FMCW lidar. For example... Figure 3As shown, an FMCW lidar includes a laser, isolator, coupler, time-delay fiber, circulator, and optical components. Additionally, it may include devices such as an ADC (Analog-to-Digital Converter, used to convert analog signals to digital signals) and a PD (Photo Detector, used to convert optical signals to electrical signals). Adding these additional optical path correction components increases the structural complexity of the lidar and also increases its cost.

[0027] To at least partially solve the aforementioned technical problems, in this embodiment, a reflective loop is added at a fixed location inside the device. This reflective loop is a fiber optic monitoring link. When calibration of the lidar is required, the scanning device is controlled to point towards the fiber optic monitoring link at the fixed location. By comparing the difference between the actual detection distance and the expected detection distance, the scanning device is calibrated. Figure 3 The complex monitoring optical path shown can be simplified by eliminating some complex optical path components, which can not only reduce the structural complexity of the lidar, but also reduce the calibration cost of the lidar.

[0028] Frequency-modulated continuous wave lidar may include a scanning device, which may be a component that emits a detection laser. This device can detect targets by emitting a frequency-modulated continuous wave signal and receiving its echo signal. Optionally, the scanning device may include a transmitter that can generate a continuous wave signal with a frequency that varies linearly with time through an internal signal source, and then transmit the generated continuous wave signal through an antenna.

[0029] When calibrating the scanning device, it can be controlled to point towards the aforementioned fiber optic monitoring link. The scanning device transmits a detection signal to the fiber optic monitoring link, and the actual detection distance corresponding to the fiber optic monitoring link is determined based on the echo signal from the link. Since the fiber optic monitoring link is located in a fixed position inside the device, the control parameters of the scanning device can be preset. By directly controlling the scanning device to point towards a fixed spatial orientation based on these preset parameters, it can be directed towards the aforementioned fiber optic monitoring link.

[0030] Since the fiber optic monitoring link is located inside the equipment and in a fixed position, the distance between the scanning equipment and the fiber optic monitoring link is fixed. Therefore, the distance between the scanning equipment and the fiber optic monitoring link can be preset, i.e., the preset detection distance. The degree of difference between the actual detection distance and the preset detection distance can characterize the degree of environmental influence on the scanning equipment. Based on the actual detection distance and the preset detection distance corresponding to the fiber optic monitoring link, specified equipment parameters of the scanning equipment can be corrected. These specified equipment parameters affect distance detection; they can affect the transmission process of the detection signal or the distance calculation process. The correction of the specified equipment parameters can be performed according to a preset correction strategy. That is, the preset correction strategy can specify the equipment parameters to be corrected for different actual detection distances, as well as the method of parameter correction.

[0031] After calibrating the specified device parameters, the scanning device can be controlled to point towards the space to be probed, and target detection can be performed by sending a detection signal to the space to be probed. If the calibration conditions (which are the conditions corresponding to the environmental parameters and required for calibrating the scanning device) are met again, the calibration can be performed again in the same or similar manner as described above, as already explained, and will not be repeated here.

[0032] The embodiments provided in this application, when calibrating a scanning device for a frequency-modulated continuous wave lidar, control the scanning device to point towards a preset fiber optic monitoring link; transmit a detection signal to the fiber optic monitoring link through the scanning device, and determine the actual detection distance corresponding to the fiber optic monitoring link based on the echo signal of the fiber optic monitoring link; based on the actual detection distance and the preset detection distance corresponding to the fiber optic monitoring link, calibrate the specified device parameters of the scanning device to obtain the calibrated specified device parameters. This solves the problems of high structural complexity and high cost of lidar in the frequency-modulated continuous wave lidar calibration methods in related technologies, and reduces the structural complexity and cost of lidar.

[0033] In an exemplary embodiment, the method further includes: obtaining the ambient temperature of the scanning device acquired at the current acquisition time to obtain the current ambient temperature; and determining that the scanning device needs to be calibrated if the temperature difference between the current ambient temperature and the reference ambient temperature is greater than or equal to a preset temperature difference threshold, wherein the reference ambient temperature is the ambient temperature of the scanning device acquired at the previous acquisition time at the current acquisition time.

[0034] Ambient temperature is a crucial factor affecting the hardware circuitry of FMCW lidar. Different temperatures can influence both the laser linewidth and the DDS (Digital Down Converter) hardware circuitry. In FMCW lidar, the laser linewidth represents its coherence, determining the theoretical detection range and accuracy. Temperature changes can cause thermal expansion or contraction in components such as the laser's gain medium and resonant cavity, affecting light propagation and reflection, thus impacting the linewidth. The DDC hardware circuitry generates the frequency-modulated continuous wave signal and controls its frequency and phase. Temperature variations can alter the performance of electronic components in the DDC circuitry, causing drift in parameters such as resistors and capacitors. These changes can lead to deviations in the frequency and phase of the generated signal, consequently affecting the ranging accuracy and velocity resolution of the FMCW lidar.

[0035] In this embodiment, the need for calibration of the scanning device can be determined based on its ambient temperature. To this end, the ambient temperature of the scanning device, acquired at the current acquisition time, can be obtained. Acquiring the ambient temperature can be done periodically, in response to a received calibration command, or based on other execution conditions. After obtaining the current ambient temperature, it can be analyzed to determine whether calibration of the scanning device is necessary. Analyzing the current ambient temperature can involve inputting it into a preset analytical model (a neural network model, which could be a classification model), and then having the preset analytical model combine this with other environmental factors to determine whether calibration of the scanning device is required.

[0036] To improve operational convenience and reduce the storage and computing resource consumption of equipment calibration, a temperature difference threshold can be preset. If the temperature difference between the current ambient temperature and the reference ambient temperature is greater than or equal to the preset temperature difference threshold, it can be determined that the scanning equipment needs calibration; if the temperature difference is less than the preset temperature difference threshold, it can be determined that no calibration is required. Alternatively, if the temperature difference is less than the preset temperature difference threshold, other environmental factors can be analyzed to further determine whether calibration is necessary.

[0037] For example, the current temperature T can be obtained, and the temperature change ΔT between the current temperature and the previous acquisition time can be calculated. If ΔT is greater than a set temperature difference threshold, the scanning device needs to be calibrated. For instance, the preset temperature difference threshold is 3℃. After the FMCW lidar is started, the ambient temperature is acquired every 5 minutes. If the current ambient temperature acquired at a certain moment is 21℃, and the previous ambient temperature was 19℃, the temperature difference is 2℃, which is less than 3℃, then no calibration of the scanning device is needed. If the previous ambient temperature was 15℃, the temperature difference is 6℃, which is greater than 3℃, then calibration of the scanning device is needed.

[0038] In this embodiment, determining whether the scanning device needs to be calibrated based on whether the change in the ambient temperature of the scanning device reaches a set temperature difference threshold can improve the convenience of operation and reduce the occupation of storage and computing resources for device calibration.

[0039] In an exemplary embodiment, the method further includes: after obtaining the ambient temperature of the scanning device acquired at the current acquisition time and obtaining the current ambient temperature, adjusting the acquisition frequency of the scanning device to a target acquisition frequency corresponding to the current ambient temperature according to a preset correspondence between ambient temperature and acquisition frequency; obtaining the ambient temperature of the scanning device acquired at the next acquisition time corresponding to the target acquisition frequency, obtaining the next ambient temperature, and determining whether to calibrate the scanning device based on the temperature difference between the next ambient temperature and the current ambient temperature.

[0040] Different environments have varying effects on scanning equipment. Generally, higher ambient temperatures have a greater impact on the laser linewidth and DDS hardware circuitry. If a uniform acquisition frequency is used, equipment calibration may be delayed or only performed after multiple judgment operations. To improve the rationality of ambient temperature acquisition, this embodiment can preset the correspondence between ambient temperature and acquisition frequency, and dynamically adjust the ambient temperature acquisition frequency according to the set correspondence.

[0041] For the current ambient temperature, the sampling frequency of the scanning device can be adjusted to a target sampling frequency corresponding to the current ambient temperature, according to a preset correspondence between ambient temperature and sampling frequency. Here, the correspondence between ambient temperature and sampling frequency can be represented by a curve, a temperature range corresponding to a sampling frequency, or other forms. This embodiment does not limit this. Based on the target sampling frequency, the next sampling time can be determined, and the ambient temperature of the scanning device collected at the next sampling time corresponding to the target sampling frequency is obtained as the next ambient temperature. The temperature difference between the next ambient temperature and the current ambient temperature is used to determine whether to calibrate the scanning device. The determination method is similar to that described above and will not be repeated here.

[0042] For example, when the ambient temperature is between 15℃ and 20℃, the sampling frequency is once every 15 minutes; when the ambient temperature is between 20℃ and 25℃, the sampling frequency is adjusted to once every 10 minutes; and when the ambient temperature exceeds 25℃, the sampling frequency is increased to once every 5 minutes. If the current ambient temperature is 23℃, based on the preset correspondence between ambient temperature and sampling frequency, the ambient temperature sampling frequency is set to once every 10 minutes. After 10 minutes, the ambient temperature of the scanning device is 25℃. The difference between this and the current ambient temperature (23℃) is 2℃, which is less than the temperature difference threshold of 3℃. Therefore, it is determined that no calibration of the scanning device is required.

[0043] In this embodiment, the sampling frequency of ambient temperature is dynamically adjusted according to the set correspondence between ambient temperature and sampling frequency, which can improve the rationality of ambient temperature sampling.

[0044] In an exemplary embodiment, determining the actual detection distance corresponding to the fiber optic monitoring link based on the echo signal of the fiber optic monitoring link includes: performing beat frequency processing on the echo signal and the local oscillator signal to obtain a beat frequency signal, wherein the local oscillator signal and the detection signal are two signals obtained by splitting the same laser beam generated by the scanning device by a beam splitter; performing frequency analysis on the beat frequency signal, and determining the actual detection distance corresponding to the fiber optic monitoring link based on the analyzed frequency information.

[0045] When the scanning device transmits a probe signal to the fiber optic monitoring link, it can split the laser beam using an internal beam splitter to obtain two signals: a probe signal and a local oscillator signal. The probe signal is transmitted to the fiber optic monitoring link by the transmitting antenna, and after being reflected by the fiber optic monitoring link, it is received by the receiving antenna to obtain the aforementioned echo signal. The received echo signal and the local oscillator signal are then subjected to beat frequency processing to obtain a beat frequency signal. This beat frequency processing can be performed by inputting both signals into a mixer. Since the frequency of the echo signal changes due to propagation distance and time delay, while the frequency of the local oscillator signal remains stable, the mixture produces a difference frequency signal, i.e., the beat frequency signal.

[0046] The beat frequency signal contains the frequency difference between the echo signal and the local oscillator signal. This frequency difference is related to the distance between the target object and the target. Therefore, by performing frequency analysis on the beat frequency signal, the actual detection distance corresponding to the fiber optic monitoring link can be determined based on the analyzed frequency information. For example, spectrum analysis can be performed on the beat frequency signal, and the actual detection distance can be calculated based on the relationship between the peak frequency and the target distance, as well as the peak frequency in the analyzed spectrum.

[0047] In this embodiment, by performing beat frequency processing on the local oscillator signals of the echo signal and the detection signal to obtain the beat frequency signal, performing frequency analysis on the beat frequency signal, and determining the actual detection distance based on the analyzed frequency information, the accuracy of the actual detection distance calculation can be guaranteed.

[0048] In an exemplary embodiment, when the scanning device of the frequency modulated continuous wave lidar is to be calibrated, controlling the scanning device to point to a preset fiber optic monitoring link includes: when the scanning device is to be calibrated, controlling the collimation and focusing of the scanning device to point to a specified angle so as to point the scanning device to the fiber optic monitoring link.

[0049] In this embodiment, the aforementioned optical device is a collimating and focusing component. Here, collimation refers to adjusting the light beam to make it as parallel as possible after being emitted from a light source, and focusing refers to concentrating the light beam to a point or a small area. The collimating and focusing component may include, but is not limited to, at least one of the following: a lens, a mirror, a beam expander, a filter, etc. To improve the convenience of device control, the angular direction of the fiber optic monitoring link relative to the scanning device can be configured, i.e., a specified angle can be specified. When the scanning device needs to be calibrated, the collimating and focusing of the scanning device can be directly controlled to point to the specified angle, thus pointing the scanning device towards the fiber optic monitoring link.

[0050] For example, if ΔT is greater than the temperature threshold, the scanning device is controlled to point at a fixed angle (ang) and emitted into the optical fiber monitoring link in space. Then, the distance D_CUR (i.e., the actual detection distance) is calculated, and the calculation is performed based on D_CUR and the set physical distance (preset detection distance).

[0051] In this embodiment, when a scanning device needs to be calibrated, the collimation and focusing of the scanning device can be controlled to point at a specified angle so that the scanning device is pointed at the fiber optic monitoring link. This can improve the convenience of device control and thus improve the efficiency of device calibration.

[0052] In an exemplary embodiment, the specified device parameters of the scanning device are corrected based on the actual detection distance and the preset detection distance corresponding to the fiber optic monitoring link to obtain the corrected specified device parameters. This includes determining the ratio between the actual detection distance and the preset detection distance as the current parameter value of the distance correction parameter of the scanning device to obtain the corrected distance correction parameter.

[0053] In this embodiment, the specified device parameters may include distance correction parameters, which are used to correct the distance detected by the scanning device. When correcting the specified device parameters, a difference analysis can be performed between the actual detection distance and the preset detection distance to determine the current value of the distance correction parameters. The difference between the actual detection distance and the preset detection distance can be the ratio between them. First, the ratio between the actual detection distance and the preset detection distance is calculated. Then, the calculated ratio is used as the current value of the distance correction parameters of the scanning device, resulting in the corrected distance correction parameters. Alternatively, the ratio between the actual detection distance and the preset detection distance can be calculated, and the product of this ratio and the current value of the distance correction parameters of the scanning device can be used to determine the corrected current parameter value. Other correction methods can also be used, as long as the corrected detection accuracy is higher than the original detection accuracy. Here, after calculating the current distance correction parameters (i.e., the corrected distance correction parameters), the calculated current distance correction parameters can be used to update the distance correction parameters.

[0054] In this embodiment, by calculating the ratio of the actual detection distance to the preset detection distance as the basis for updating the distance correction parameters, the convenience of equipment calibration can be improved, thereby maintaining the accuracy and reliability of the measurement results.

[0055] In one exemplary embodiment, when there are multiple scanning devices, each scanning device can be configured with a corresponding fiber optic monitoring link. However, multiple fiber optic monitoring links not only increase the complexity of the lidar structure but also increase the cost of the lidar. To reduce the complexity and cost of the lidar structure, multiple scanning devices can share the same fiber optic monitoring link, allowing only one scanning device to use the fiber optic monitoring link at any given time, with different scanning devices corresponding to different enable time periods.

[0056] Correspondingly, the above method also includes: determining whether to perform calibration on each scanning device within the enable time period corresponding to each scanning device. The enable time periods of two adjacent scanning devices can be adjacent or non-adjacent, as long as it is ensured that only one scanning device is allowed to use the fiber optic monitoring link at the same time, so as to realize the monitoring and correction function of multiple lasers under a single optical path.

[0057] For example, such as Figure 4 As shown, the FMCW lidar includes three scanning devices: Scanning Device A, Scanning Device B, and Scanning Device C. Each scanning device has an enable period of 10 minutes. Scanning Device A is enabled from 10:00 to 10:10, Scanning Device B from 10:10 to 10:20, and Scanning Device C from 10:20 to 10:30. The three scanning devices cycle sequentially. Within their respective enable periods, the scanning devices can perform calibration operations using the fiber optic monitoring link.

[0058] In this embodiment, multiple scanning devices share the same set of fiber optic monitoring links, which can reduce the complexity and cost of the lidar structure while enabling the calibration of multiple scanning devices. At the same time, different scanning devices correspond to different enable time periods (i.e., the time periods during which the fiber optic monitoring links are allowed to be used), which can avoid signal interference between different scanning devices.

[0059] 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.

[0060] 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 described in the various embodiments of this application.

[0061] 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.

[0062] Figure 5 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 5 As shown, the frequency-modulated continuous wave lidar system includes: a scanning component 502, an optical fiber monitoring link 504, and a control component 506. The control component 502 is used to control the scanning device to point towards the optical fiber monitoring link 504 when calibration is required; to control the scanning device to transmit a detection signal to the optical fiber monitoring link 504, and to determine the actual detection distance corresponding to the optical fiber monitoring link 504 based on the echo signal from the optical fiber monitoring link 504; to calibrate specified device parameters of the scanning device based on the actual detection distance and the preset detection distance corresponding to the optical fiber monitoring link, thereby obtaining the calibrated specified device parameters; the scanning component 502 is used to respond to the control of the control component by pointing towards the optical fiber monitoring link; to transmit a detection signal to the optical fiber monitoring link; and to receive the echo signal from the optical fiber monitoring link.

[0063] It should be noted that the control unit 506 in this embodiment can be used to execute steps S202, S204 and S206 in the foregoing embodiments.

[0064] The embodiments provided in this application, when calibrating a scanning device for a frequency-modulated continuous wave lidar, control the scanning device to point towards a preset fiber optic monitoring link; transmit a detection signal to the fiber optic monitoring link through the scanning device, and determine the actual detection distance corresponding to the fiber optic monitoring link based on the echo signal of the fiber optic monitoring link; based on the actual detection distance and the preset detection distance corresponding to the fiber optic monitoring link, calibrate the specified device parameters of the scanning device to obtain the calibrated specified device parameters. This solves the problems of high structural complexity and high cost of lidar in the frequency-modulated continuous wave lidar calibration methods in related technologies, and reduces the structural complexity and cost of lidar.

[0065] In one exemplary embodiment, the system further includes a temperature sensor for monitoring the ambient temperature of the scanning device; the control unit is further configured to acquire the ambient temperature of the scanning device monitored by the temperature sensor at the current acquisition time to obtain the current ambient temperature; and determine that the scanning device needs to be calibrated if the temperature difference between the current ambient temperature and the reference ambient temperature is greater than or equal to a preset temperature difference threshold, wherein the reference ambient temperature is the ambient temperature of the scanning device acquired at the previous acquisition time at the current acquisition time.

[0066] In an exemplary embodiment, the control component is further configured to determine the ratio between the actual detection distance and the preset detection distance as the current parameter value of the distance correction parameter of the scanning device, thereby obtaining the corrected distance correction parameter, wherein the specified device parameter includes the distance correction parameter, which is a parameter used to correct the distance detected by the scanning device.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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 communication section 609, and / or installed from removable medium 611. When the computer program is executed by central processing unit 601, 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.

[0073] Figure 6 A schematic block diagram of a computer system architecture for implementing embodiments of the present application is shown. Figure 6 As shown, the computer system 600 includes a CPU (Central Processing Unit) 601, which can perform various appropriate actions and processes based on programs stored in ROM 602 or programs loaded into RAM 603 from storage section 608. Random access memory 603 also stores various programs and data required for system operation. The CPU 601, ROM 602, and RAM 603 are interconnected via bus 604. An I / O (Input / Output) interface 605 is also connected to bus 604.

[0074] The following components are connected to I / O interface 605: an input section 606 including a keyboard, mouse, etc.; an output section 607 including CRT (Cathode Ray Tube), LCD (Liquid Crystal Display), and speakers, etc.; a storage section 608 including a hard disk, etc.; and a communication section 609 including a network interface card, such as a LAN card or modem, etc. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to I / O interface 605 as needed. A removable medium 611, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 610 as needed so that computer programs read from it can be installed into storage section 608 as needed.

[0075] 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 609, and / or installed from removable medium 611. When the computer program is executed by central processing unit 601, it performs various functions defined in the system of this application.

[0076] It should be noted that, Figure 6 The computer system 600 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.

[0077] 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.

[0078] 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 method for correcting a frequency-modulated continuous wave lidar, characterized in that, include: When the scanning device of the frequency modulated continuous wave lidar needs to be calibrated, the scanning device is controlled to point to a preset fiber optic monitoring link. The scanning device transmits a detection signal to the optical fiber monitoring link and determines the actual detection distance corresponding to the optical fiber monitoring link based on the echo signal of the optical fiber monitoring link. Based on the actual detection distance and the preset detection distance corresponding to the optical fiber monitoring link, the specified device parameters of the scanning device are corrected to obtain the corrected specified device parameters.

2. The method according to claim 1, characterized in that, The method further includes: Obtain the ambient temperature of the scanning device at the current acquisition time to obtain the current ambient temperature; If the temperature difference between the current ambient temperature and the reference ambient temperature is greater than or equal to a preset temperature difference threshold, it is determined that the scanning device needs to be calibrated, wherein the reference ambient temperature is the ambient temperature of the scanning device acquired at the previous acquisition time.

3. The method according to claim 2, characterized in that, After obtaining the ambient temperature of the scanning device acquired at the current acquisition time, the method further includes: According to the preset correspondence between ambient temperature and acquisition frequency, the acquisition frequency for acquiring the ambient temperature of the scanning device is adjusted to the target acquisition frequency corresponding to the current ambient temperature; The ambient temperature of the scanning device is acquired at the next acquisition time corresponding to the target acquisition frequency, the next ambient temperature is obtained, and a determination is made on whether to calibrate the scanning device based on the temperature difference between the next ambient temperature and the current ambient temperature.

4. The method according to claim 1, characterized in that, The determination of the actual detection distance corresponding to the optical fiber monitoring link based on the echo signal of the optical fiber monitoring link includes: The echo signal and the local oscillator signal are subjected to beat frequency processing to obtain a beat frequency signal. The local oscillator signal and the detection signal are two signals obtained by splitting the same laser beam generated by the scanning device by a beam splitter. The beat frequency signal is analyzed for frequency, and based on the analyzed frequency information, the actual detection distance corresponding to the optical fiber monitoring link is determined.

5. The method according to claim 1, characterized in that, When the scanning device of the frequency-modulated continuous wave lidar is to be calibrated, controlling the scanning device to point to a preset fiber optic monitoring link includes: When the scanning device needs to be calibrated, the collimation and focusing of the scanning device is controlled to point at a specified angle so that the scanning device is pointed at the optical fiber monitoring link, wherein the optical fiber monitoring link is located in the specified angle direction of the scanning device.

6. The method according to claim 1, characterized in that, The step of correcting specified device parameters of the scanning device based on the actual detection distance and the preset detection distance corresponding to the fiber optic monitoring link to obtain the corrected specified device parameters includes: The ratio between the actual detection distance and the preset detection distance is determined as the current parameter value of the distance correction parameter of the scanning device, and the corrected distance correction parameter is obtained. The specified device parameter includes the distance correction parameter, which is a parameter used to correct the distance detected by the scanning device.

7. The method according to any one of claims 1 to 6, characterized in that, The number of scanning devices is multiple; the method further includes: During the enable time period corresponding to each of the scanning devices, it is determined whether to calibrate each of the scanning devices. The fiber optic monitoring link is shared by multiple scanning devices, and the fiber optic monitoring link is only allowed to be used by one of the scanning devices at any given time.

8. A frequency-modulated continuous wave lidar system, characterized in that, include: Scanning components, fiber optic monitoring links, and control components, among which, The control component is used to control the scanning device to point to the optical fiber monitoring link when the scanning device needs to be calibrated; control the scanning device to transmit a detection signal to the optical fiber monitoring link, and determine the actual detection distance corresponding to the optical fiber monitoring link based on the echo signal of the optical fiber monitoring link; and calibrate the specified device parameters of the scanning device based on the actual detection distance and the preset detection distance corresponding to the optical fiber monitoring link to obtain the calibrated specified device parameters. The scanning component is configured to, in response to the control of the control component, point to the optical fiber monitoring link; transmit the detection signal to the optical fiber monitoring link; and receive the echo signal from the optical fiber monitoring link.

9. The system according to claim 8, characterized in that, The system also includes a temperature sensor, wherein... The temperature sensor is used to monitor the ambient temperature of the scanning device; The control component is further configured to acquire the ambient temperature of the scanning device monitored by the temperature sensor at the current acquisition time, and obtain the current ambient temperature; if the temperature difference between the current ambient temperature and the reference ambient temperature is greater than or equal to a preset temperature difference threshold, determine that the scanning device needs to be calibrated, wherein the reference ambient temperature is the ambient temperature of the scanning device acquired at the previous acquisition time at the current acquisition time.

10. The system according to claim 8, characterized in that, The control component is further configured to determine the ratio between the actual detection distance and the preset detection distance as the current parameter value of the distance correction parameter of the scanning device, thereby obtaining the corrected distance correction parameter. The specified device parameter includes the distance correction parameter, which is a parameter used to correct the distance detected by the scanning device.

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