Ranging method and ranging system based on frequency-modulated continuous-wave lidar

Abstract

This application provides a ranging method and system based on a frequency-modulated continuous wave (FM-CW) lidar. The method includes: when using an FM-CW lidar to measure distance at a specified scanning angle, during a first ranging period, scanning at least one scanning angle within a specified angle range using the FM-CW lidar to obtain at least one ranging signal segment. The first ranging period corresponds to the specified scanning angle, and the specified angle range includes the specified scanning angle. Distance calculation is performed on the first ranging signal in the at least one ranging signal segment, and the calculated ranging result is determined as the first ranging result corresponding to the specified scanning angle. The signal-to-noise ratio (SNR) of the first ranging signal is greater than or equal to a SNR threshold. This application solves the problem of poor ranging accuracy due to poor speckle morphology in related ranging methods based on FM-CW lidar.

Description

Technical Field

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

[0002] In FMCW (Frequency Modulated Continuous Wave) lidar ranging, the surface roughness of objects can cause speckle patterns. These speckles affect the phase consistency and intensity of the echo signal, thus impacting ranging capability. Poor speckle patterns may even result in no echo signal.

[0003] Therefore, it can be seen that the ranging method based on frequency-modulated continuous wave lidar in related technologies suffers from poor ranging accuracy due to the poor speckle morphology. Summary of the Invention

[0004] This application provides a ranging method and system based on frequency-modulated continuous wave lidar, which at least solves the technical problem of poor ranging accuracy caused by poor speckle morphology in the ranging method based on frequency-modulated continuous wave lidar in the related art.

[0005] According to one aspect of the embodiments of this application, a ranging method based on a frequency-modulated continuous wave lidar is provided, comprising: when using the frequency-modulated continuous wave lidar to measure distance at a specified scanning angle, during a first ranging period, using the frequency-modulated continuous wave lidar to scan at least one scanning angle within a specified angle range to obtain at least one ranging signal, wherein the first ranging period corresponds to the specified scanning angle, and the specified angle range includes the specified scanning angle; performing distance calculation on a first ranging signal in the at least one ranging signal, and determining the calculated ranging result as a first ranging result corresponding to the specified scanning angle, wherein the signal-to-noise ratio of the first ranging signal is greater than or equal to a signal-to-noise ratio threshold.

[0006] According to another aspect of the embodiments of this application, a ranging system based on a frequency-modulated continuous wave lidar is also provided, comprising: a control unit and a frequency-modulated continuous wave lidar; wherein, the control unit is configured to, when using the frequency-modulated continuous wave lidar to measure distance at a specified scanning angle, scan at least one scanning angle within a specified angle range using the frequency-modulated continuous wave lidar within a first ranging period, to obtain at least one ranging signal, wherein the first ranging period corresponds to the specified scanning angle, and the specified angle range includes the specified scanning angle; perform distance calculation on a first ranging signal in the at least one ranging signal, and determine the calculated ranging result as a first ranging result corresponding to the specified scanning angle, wherein the signal-to-noise ratio of the first ranging signal is greater than or equal to a signal-to-noise ratio threshold; the frequency-modulated continuous wave lidar is configured to perform a scanning operation in response to the control of the control unit.

[0007] This application employs a method of dynamically scanning an angle range near a specified scanning angle and selecting the ranging result based on the signal-to-noise ratio (SNR) of the obtained ranging signal. When using a frequency-modulated continuous wave (FMCH) lidar to measure distances at a specified scanning angle, within a first ranging cycle, the FMCH lidar scans at least one scanning angle within the specified angle range to obtain at least one ranging signal segment. The first ranging cycle corresponds to the specified scanning angle, and the specified angle range includes the specified scanning angle. Distance calculation is performed on the first ranging signal within the at least one ranging signal segment, and the calculated ranging result is determined as the first ranging result corresponding to the specified scanning angle. The SNR of the first ranging signal is greater than or equal to a SNR threshold. By scanning at least one scanning angle within an angle range near the specified scanning angle and selecting the scanning angle with better speckle morphology based on the SNR of the scanning result as the scanning result corresponding to the specified scanning angle, the quality of the speckle morphology can be guaranteed, thereby improving the ranging accuracy. This solves the problem of poor ranging accuracy caused by poor speckle morphology in related ranging methods based on FMCH lidar. Attached Figure Description

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

[0009] Figure 2 This is a flowchart illustrating an optional ranging method based on frequency-modulated continuous wave lidar according to an embodiment of this application.

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

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

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

[0013] Figure 6 This is a structural block diagram of an optional ranging system based on frequency-modulated continuous wave lidar according to an embodiment of this application;

[0014] Figure 7 This is a computer system architecture block diagram of an optional electronic device according to an embodiment of this application. Detailed Implementation

[0015] 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.

[0016] 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.

[0017] According to one aspect of the embodiments of this application, a ranging method based on a frequency-modulated continuous wave lidar is provided. Optionally, in this embodiment, the above-described ranging method based on a frequency-modulated continuous wave lidar can be applied, but is not limited to, to applications such as... Figure 1The 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, etc.) 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 for server 104.

[0018] 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. Optionally, the LiDAR 102 may be an FMCW LiDAR, and the server 104 may be, but is not limited to, a cloud server, a server cluster, or other server types.

[0019] The ranging method based on frequency-modulated continuous wave lidar in this application embodiment can be executed by lidar 102 alone, or by lidar 102 and server 104 jointly. Alternatively, the ranging method based on frequency-modulated continuous wave lidar in this application embodiment can be executed by a control component integrated on lidar 102.

[0020] Taking the ranging method based on frequency-modulated continuous wave lidar in this embodiment, executed by lidar 102, as an example, Figure 2 This is a schematic flowchart of an optional ranging method based on frequency-modulated continuous wave lidar according to an embodiment of this application, as shown below. Figure 2 As shown, the process of this method may include the following steps:

[0021] Step S202: When using a frequency-modulated continuous wave lidar to measure the distance at a specified scanning angle, during the first ranging cycle time, the frequency-modulated continuous wave lidar is used to scan at least one scanning angle within the specified angle range to obtain at least one ranging signal. The first ranging cycle time corresponds to the specified scanning angle, and the specified angle range includes the specified scanning angle.

[0022] Step S204: Perform distance calculation on the first ranging signal in at least one ranging signal segment, and determine the calculated ranging result as the first ranging result corresponding to the specified scanning angle, wherein the signal-to-noise ratio of the first ranging signal is greater than or equal to the signal-to-noise ratio threshold.

[0023] The ranging method based on frequency-modulated continuous wave (FMCW) lidar in this embodiment can be applied to the lidar field, in scenarios requiring high-precision ranging, object detection in complex environments, and sensitivity to speckle effects. Taking autonomous driving as an example, in autonomous vehicles, lidar is used for distance measurement. Its working principle is as follows: FMCW lidar emits a continuous beam of light, and the frequency modulates linearly with time. The distance to the target can be determined by measuring the frequency difference between the emitted signal and the received echo signal.

[0024] In FMCW lidar ranging, when laser light illuminates a surface with a roughness greater than the laser wavelength, the laser light is reflected and scattered, forming an uneven, granular distribution, known as the speckle effect. The speckle effect causes changes in the phase and amplitude of the reflected light wave, thus reducing the accuracy and reliability of ranging. For example, the speckle effect may cause uneven intensity distribution of the laser signal, affecting the receiving sensitivity of the ranging system and making the ranging signal unstable; the speckle effect may also cause changes in the laser illumination position, increasing the noise level of the ranging system and reducing ranging accuracy; the speckle effect may also cause some fringes in the interference pattern to disappear completely, i.e., fringe loss, leading to errors in the ranging results; the speckle effect can also introduce additional phase errors and time delay errors, thus affecting the accuracy of the ranging results.

[0025] To at least partially solve the above-mentioned technical problems, in this embodiment, a method is adopted to dynamically scan the angle range near the specified scanning angle and select the ranging result based on the signal-to-noise ratio of the obtained ranging signal. Since at least one scanning angle in the angle range near the specified scanning angle is scanned, and the scanning angle with better speckle morphology is selected as the scanning result corresponding to the specified scanning angle based on the signal-to-noise ratio of the scanning result, the purpose of ensuring speckle morphology quality can be achieved, thereby improving the technical effect of ranging accuracy.

[0026] In FMCW lidar ranging, the scanning results at angles near a specified scanning angle are strongly correlated with the scanning results at that specified scanning angle and can represent the situation at that specified scanning angle. The signal-to-noise ratio (SNR) directly reflects the ratio of effective information to noise in the received signal. A high SNR means that the received signal contains a higher proportion of effective information and less noise interference, resulting in higher ranging accuracy. Therefore, selecting measurement results with an SNR greater than a threshold from at least one scanning angle within a certain angle range near the specified scanning angle for calculation can improve ranging accuracy.

[0027] In this embodiment, when using a frequency-modulated continuous wave lidar to measure distances at a specified scanning angle, within the first ranging cycle, the frequency-modulated continuous wave lidar can scan at least one scanning angle within the specified angle range to obtain at least one ranging signal. The ranging signal can reflect the intensity and phase information of the reflected signal of the target object at different angles.

[0028] FMCW lidar can perform ranging operations periodically. That is, within one ranging cycle, a scan is performed at a specific scanning angle (the scan lasts for a certain period), and then within the next ranging cycle, a scan is performed at the next scanning angle. The ranging cycle time corresponding to the specified scanning angle is defined as the first ranging cycle time. The length of the first ranging cycle time can be set based on the FMCW lidar's performance parameters and ranging method, external environmental parameters, detection task requirements, and the operator's experience.

[0029] The specified angle range mentioned above includes the specified scanning angle, which can be the scanning angle range obtained by shifting a certain angle to the left or right with the specified scanning angle as the center, or the scanning angle range obtained by shifting a certain angle to the left or right with the specified scanning angle as the boundary.

[0030] Optionally, the FMCW lidar can be an OPA lidar. It can be based on an OPA array and move randomly or systematically within a scanning angular resolution range. An OPA array is a technique that uses phase control of light waves to achieve beam direction adjustment. By adjusting the phase of each element in the array, the direction and shape of the output beam can be precisely controlled. The scanning angular resolution is the smallest angular difference that the OPA array can resolve; that is, it determines the accuracy of beam direction adjustment.

[0031] For example, if the scanning angle resolution of the FMCW lidar is 1 degree and the specified scanning angle is 10 degrees, then the specified angle range can be from 9.5 degrees to 10.5 degrees. Within the specified angle range, the FMCW lidar scans at least one scanning angle within the 9.5-10.5 degree angle range to obtain at least one range signal.

[0032] If at least one ranging signal contains a ranging result with a signal-to-noise ratio greater than or equal to the signal-to-noise ratio threshold, any ranging result or a specified ranging result can be used to calculate the distance to obtain the ranging result for distance calculation. The calculated ranging result is then determined as the first ranging result corresponding to the specified scanning angle.

[0033] The signal-to-noise ratio threshold can be set according to the actual application environment and the performance parameters of the FMCW lidar to ensure that the selected signal has sufficient reliability and accuracy. The distance calculation method for the selected first ranging signal can be: analyzing the frequency information and determining the distance between the target object and the lidar based on the analyzed frequency information.

[0034] Here, when calculating the ranging signal, an FFT (Fast Fourier Transform) transformation can be performed on the ranging signal to obtain its frequency domain information; the calculated distance can be obtained by finding peak values ​​in the frequency domain information. FFT is a fast calculation method that generates a power spectrum based on the 2nd to nth power data points of a waveform. The frequency domain waveform will differ under different FFT integration times. When the integration time is short, i.e., the number of data points collected is small, the frequency resolution of the FFT analysis will decrease; when the integration time is long, i.e., the number of data points collected is large, the frequency resolution of the FFT analysis will increase.

[0035] The embodiments provided in this application, when using a frequency-modulated continuous wave lidar to measure distances at a specified scanning angle, involve scanning at least one scanning angle within a specified angle range using the frequency-modulated continuous wave lidar within a first ranging period to obtain at least one ranging signal. The first ranging period corresponds to the specified scanning angle, and the specified angle range includes the specified scanning angle. Distance calculation is performed on the first ranging signal within the at least one ranging signal, and the calculated ranging result is determined as the first ranging result corresponding to the specified scanning angle. The signal-to-noise ratio (SNR) of the first ranging signal is greater than or equal to a SNR threshold. This solves the problem of poor ranging accuracy caused by poor speckle morphology in related ranging methods based on frequency-modulated continuous wave lidar, thereby improving ranging accuracy.

[0036] In an exemplary embodiment, in order to perform fine-grained multi-segment scanning within a first ranging cycle time to obtain ranging signals at at least one scanning angle, the first ranging cycle time (which can be denoted as N) can be divided into M sub-segments (M is a positive integer greater than or equal to 2). Then, the time of each small ranging cycle is N / M. For example, if the first ranging cycle time is 100ms and M is set to 5, then the length of each sub-segment is 100ms / 5, or 20ms.

[0037] Correspondingly, during the first ranging cycle, the frequency-modulated continuous wave lidar is used to scan at least one scanning angle within a specified angle range to obtain at least one ranging signal, including: during each of the M sub-time periods, the frequency-modulated continuous wave lidar is used to scan one scanning angle within a specified angle range to obtain a ranging signal corresponding to each sub-time period.

[0038] Within each of the M sub-time periods, an FMCW lidar can be used to scan a specified angle range to obtain a ranging signal corresponding to each sub-time period. At least one ranging signal segment includes the ranging signal corresponding to each sub-time period. The scanning angles corresponding to different sub-time periods can be the same or different.

[0039] For example, at least one scanning angle within the angular range of 9.5 degrees to 10.5 degrees can be scanned. Within each 20ms sub-time period, the lidar can scan a specific scanning angle within the angular range of 9.5 degrees to 10.5 degrees to obtain the ranging signal corresponding to that scanning angle.

[0040] In this embodiment, the ranging cycle time is divided into M sub-time periods, and a scanning angle within a specified angle range is scanned in each sub-time period. This can improve the convenience and stability of the lidar ranging (the scanning of each scanning angle can last for a certain period of time).

[0041] In an exemplary embodiment, within each of the M sub-time periods, a frequency-modulated continuous wave lidar is used to scan a scanning angle within a specified angle range to obtain a ranging signal corresponding to each sub-time period. This includes: within each sub-time period, a frequency-modulated continuous wave lidar is used to scan a random scanning angle within a specified angle range to obtain a ranging signal corresponding to each sub-time period.

[0042] In this embodiment, a scanning angle (i.e., a random scanning angle) can be randomly selected from a specified angular range within each sub-time period for ranging, thereby obtaining a ranging signal corresponding to each sub-time period. Randomly selecting the scanning angle can cover more possibilities of scanning angles, avoiding the influence of speckle effect at specific angles on the ranging results. Through random scanning, even in complex environments, it can be guaranteed that a ranging signal with a good signal-to-noise ratio can be scanned within a specified angular range. This random scanning strategy increases the probability of obtaining high-quality data.

[0043] Optionally, a random algorithm can be combined with the lidar control strategy to randomly select a scanning angle from a specified angular range for ranging within each sub-time period. In the lidar control strategy, a specific command or parameter can be designed to instruct the lidar to perform random angle scanning. This command can be predefined; for example, sending a specific scanning command allows the lidar to automatically select a random angle within the specified angular range for scanning.

[0044] For example, such as Figure 3 As shown, within each 20ms sub-time period, the lidar can scan a random scanning angle within the angle range of 9.5 degrees to 10.5 degrees, and obtain the ranging signals corresponding to 5 random scanning angles.

[0045] In this embodiment, a random scan is performed on a specified angle range within each sub-time period. Randomly selecting the scanning angle can cover more possibilities of the scanning angle, thereby improving the performance of lidar ranging.

[0046] In one exemplary embodiment, each of the M sub-time periods corresponds to a scanning angle obtained by equally dividing a specified angle range. For different angle division strategies, the scanning angle corresponding to the same sub-time period can be different. Angle division strategies can be, but are not limited to, one of the following: including two endpoint angles, with the specified angle range equally divided into M-1 parts; including the minimum angle, with the specified angle range equally divided into M parts; including the maximum angle, with the specified angle range equally divided into M parts; not including two endpoint angles, with the specified angle range equally divided into M+1 parts.

[0047] In this embodiment, within each of the M sub-time periods, a frequency-modulated continuous wave lidar is used to scan a scanning angle within a specified angle range to obtain a ranging signal corresponding to each sub-time period. This includes: within each sub-time period, a frequency-modulated continuous wave lidar is used to scan a scanning angle corresponding to each sub-time period to obtain a ranging signal corresponding to each sub-time period.

[0048] Since each sub-time period corresponds to a scanning angle, the angle difference between the scanning angles of two adjacent sub-time periods can be the same or different. That is, the scanning angles corresponding to each sub-time period can increase or decrease sequentially, or the scanning angles corresponding to each sub-time period can be randomly selected sequentially from the divided scanning angles. This embodiment does not impose any limitations on this. Here, using scanning angles obtained by equally dividing a specified angle range for scanning can improve the convenience of lidar scanning control.

[0049] For example, the angle division strategy could be: including the minimum angle, the specified angle range is divided into 5 equal parts. The angle range of 9.5 degrees to 10.5 degrees is divided into 5 equal parts. Within each 20ms sub-time period, the lidar can scan a certain equally divided scanning angle within the 9.5 degrees to 10.5 degrees angle range, obtaining the ranging signals corresponding to the 5 scanning angles, such as... Figure 4 As shown.

[0050] This embodiment improves the convenience of lidar scanning control by dividing the specified angle range into equal parts within each sub-time period.

[0051] In one exemplary embodiment, during a first ranging period, a frequency-modulated continuous wave lidar is used to scan at least one scanning angle within a specified angle range to obtain at least one ranging signal. The method further includes: if the signal-to-noise ratio of the ranging signal corresponding to the Nth sub-time period in the M sub-time periods is greater than or equal to a signal-to-noise ratio threshold, and the Nth sub-time period is not the last sub-time period of the M sub-time periods, controlling the scanning angle of the frequency-modulated continuous wave lidar to remain at the scanning angle corresponding to the Nth sub-time period.

[0052] Within each sub-time period, the lidar scans an angle within a specified angular range. Signal-to-noise ratio (SNR) analysis is performed on the acquired ranging signal to determine if its signal quality is greater than or equal to a preset SNR threshold. By real-time detection of the ranging signal SNR, subsequent scanning angles can be dynamically adjusted to quickly locate and focus on high-signal-quality scanning angles in complex environments.

[0053] If the signal-to-noise ratio (SNR) of the ranging signal corresponding to the Nth sub-time period out of M sub-time periods is greater than or equal to the SNR threshold, and the Nth sub-time period is not the last sub-time period of the M sub-time periods, then its scanning strategy can be adjusted. Specifically, the scanning angle of the frequency-modulated continuous wave lidar can be controlled to remain at the scanning angle corresponding to the Nth sub-time period, thereby increasing the scanning time at the scanning angle corresponding to the Nth sub-time period. A longer scanning time results in more ranging signals being acquired, leading to higher accuracy and efficiency in the calculation.

[0054] Here, the adjustment method of the above scanning strategy applies to both random scanning and evenly distributed scanning. The scanning angle corresponding to the sub-time period after the Nth sub-time period is the same as the scanning angle corresponding to the Nth sub-time period, and the first ranging signal includes the ranging signal corresponding to the Nth sub-time period and the ranging signal corresponding to the sub-time period after the Nth sub-time period.

[0055] For example, if the set signal-to-noise ratio (SNR) threshold is 3dB, and the SNR of the ranging signal corresponding to the third sub-time period is greater than or equal to the SNR threshold, then the scanning angles corresponding to the fourth and fifth sub-time periods are both 9.9°. Figure 5 As shown.

[0056] In this embodiment, by enhancing the scanning angle with a better spot shape, it is possible to focus on a high signal-to-noise ratio angle, thereby improving the reliability of lidar ranging.

[0057] In an exemplary embodiment, after scanning at least one scanning angle within a specified angle range using a frequency-modulated continuous wave lidar during a first ranging period, the method further includes: if the signal-to-noise ratio (SNR) of the ranging signal with the highest SNR in at least one ranging signal is greater than or equal to a SNR threshold, then the ranging signal with the highest SNR is determined as the first ranging signal.

[0058] After scanning at least one angle within a specified angular range during the first ranging cycle, the acquired ranging signal can be analyzed based on the signal-to-noise ratio (SNR). The signal with the highest SNR can be selected as the first ranging signal for distance calculation to ensure the accuracy and reliability of the ranging results.

[0059] Optionally, all acquired ranging signals can be sorted in descending order of signal-to-noise ratio (SNR), and the ranging signal with the highest SNR can be selected. The selected ranging signal with the highest SNR can then be verified. If the SNR of the ranging signal with the highest SNR is greater than or equal to a SNR threshold, it can be determined as the first ranging signal for distance calculation.

[0060] In this embodiment, by selecting the ranging signal with the highest signal-to-noise ratio as the ranging signal used for distance calculation, the influence of speckle effect is reduced, thereby improving the accuracy and reliability of ranging.

[0061] In an exemplary embodiment, the specified angle range is the angle range obtained by offsetting the specified scanning angle to the left and right by half the scanning angle resolution of the frequency-modulated continuous wave lidar, with the specified scanning angle as the center. The first ranging signal corresponds to the target scanning angle within the specified angle range.

[0062] In this embodiment, historical information from angle scanning can be referenced for subsequent angle ranging. Correspondingly, after determining the calculated ranging result as the first ranging result corresponding to the specified scanning angle, the method further includes: when using a frequency-modulated continuous wave lidar to measure the distance to the specified scanning angle again, during a second ranging cycle, using a frequency-modulated continuous wave lidar to scan the target scanning angle to obtain a second ranging signal, wherein the second ranging cycle corresponds to the specified scanning angle; and when the signal-to-noise ratio of the second ranging signal is greater than or equal to a signal-to-noise ratio threshold, performing distance calculation on the second ranging signal to obtain the second ranging result corresponding to the specified scanning angle.

[0063] In this embodiment, if ranging is performed again at the specified scanning angle, the target scanning angle can be directly scanned using a frequency-modulated continuous wave lidar within the second ranging cycle time to obtain a second ranging signal. The second ranging cycle time is the ranging cycle time corresponding to the previous specified scanning angle. Here, scanning the target scanning angle can continue for the entire second ranging cycle time or for a sub-time period.

[0064] If the signal-to-noise ratio (SNR) of the second ranging signal is greater than or equal to the SNR threshold, the distance can be calculated from the second ranging signal to obtain the second ranging result corresponding to the specified scanning angle. If the SNR of the second ranging signal is less than the SNR threshold, the specified angle range can be randomly scanned or evenly scanned in the same or similar manner as described above. This has already been explained and will not be repeated here.

[0065] By referencing the ranging results of historical ranging cycles in this embodiment, the scanning angle used for angle scanning during the current ranging cycle can be selected, ensuring the effectiveness of angle scanning control and thus improving the accuracy and reliability of lidar ranging.

[0066] 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.

[0067] 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.

[0068] According to another aspect of the embodiments of this application, a ranging system based on frequency-modulated continuous wave lidar is also provided. This ranging system can be used to implement the ranging method based on frequency-modulated continuous wave lidar provided in the above embodiments, and will not be repeated hereafter. 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.

[0069] Figure 6 This is a structural block diagram of an optional ranging system based on a frequency-modulated continuous wave lidar according to an embodiment of this application, such as... Figure 6 As shown, the ranging system based on frequency-modulated continuous wave lidar includes: a control unit 602 and a frequency-modulated continuous wave lidar 604; wherein, the control unit 602 is used to, when using the frequency-modulated continuous wave lidar to measure distance at a specified scanning angle, scan at least one scanning angle within a specified angle range using the frequency-modulated continuous wave lidar within a first ranging period, to obtain at least one ranging signal, wherein the first ranging period corresponds to the specified scanning angle, and the specified angle range includes the specified scanning angle; perform distance calculation on the first ranging signal in the at least one ranging signal, and determine the calculated ranging result as the first ranging result corresponding to the specified scanning angle, wherein the signal-to-noise ratio of the first ranging signal is greater than or equal to a signal-to-noise ratio threshold; the frequency-modulated continuous wave lidar 604 is used to perform scanning operations in response to the control of the control unit.

[0070] It should be noted that the control unit 602 in this embodiment can be used to execute steps S202 and S204 in the foregoing embodiments.

[0071] The embodiments provided in this application, when using a frequency-modulated continuous wave lidar to measure distances at a specified scanning angle, involve scanning at least one scanning angle within a specified angle range using the frequency-modulated continuous wave lidar within a first ranging period to obtain at least one ranging signal. The first ranging period corresponds to the specified scanning angle, and the specified angle range includes the specified scanning angle. Distance calculation is performed on the first ranging signal within the at least one ranging signal, and the calculated ranging result is determined as the first ranging result corresponding to the specified scanning angle. The signal-to-noise ratio (SNR) of the first ranging signal is greater than or equal to a SNR threshold. This solves the problem of poor ranging accuracy caused by poor speckle morphology in related ranging methods based on frequency-modulated continuous wave lidar, thereby improving ranging accuracy.

[0072] In one exemplary embodiment, the first ranging cycle time is divided into M sub-time periods, where M is a positive integer greater than or equal to 2. The control unit is further configured to, within each of the M sub-time periods, use a frequency-modulated continuous wave lidar to scan a scanning angle within a specified angle range to obtain a ranging signal corresponding to each sub-time period, wherein at least one segment of the ranging signal includes the ranging signal corresponding to each sub-time period.

[0073] In one exemplary embodiment, the control unit is further configured to scan a random scanning angle within a specified angle range using a frequency-modulated continuous wave lidar within each sub-time period to obtain a ranging signal corresponding to each sub-time period.

[0074] In one exemplary embodiment, each of the M sub-time periods corresponds to a scanning angle obtained by equally dividing a specified angle range. The control unit is further configured to scan the scanning angle corresponding to each sub-time period using a frequency-modulated continuous wave lidar within each sub-time period to obtain a ranging signal corresponding to each sub-time period.

[0075] In one exemplary embodiment, the control unit is further configured to control the scanning angle of the frequency-modulated continuous wave lidar to remain at the scanning angle corresponding to the Nth sub-time period when the signal-to-noise ratio of the ranging signal corresponding to the Nth sub-time period in the M sub-time periods is greater than or equal to a signal-to-noise ratio threshold and the Nth sub-time period is not the last sub-time period of the M sub-time periods. The scanning angles corresponding to sub-time periods after the Nth sub-time period are all the scanning angles corresponding to the Nth sub-time period. The first ranging signal includes the ranging signal corresponding to the Nth sub-time period and the ranging signal corresponding to sub-time periods after the Nth sub-time period.

[0076] In one exemplary embodiment, the control unit is further configured to, after scanning at least one scanning angle within a specified angle range using a frequency-modulated continuous wave lidar during a first ranging period, determine the ranging signal with the highest signal-to-noise ratio as the first ranging signal if the signal-to-noise ratio of the ranging signal with the highest signal-to-noise ratio among at least one ranging signal is greater than or equal to a signal-to-noise ratio threshold.

[0077] In an exemplary embodiment, the specified angle range is an angle range obtained by offsetting the specified scanning angle to the left and right by half the scanning angle resolution of the frequency-modulated continuous wave lidar, with the specified scanning angle as the center. The first ranging signal corresponds to the target scanning angle within the specified angle range. The control unit is further configured to, after determining the calculated ranging result as the first ranging result corresponding to the specified scanning angle, and when using the frequency-modulated continuous wave lidar to measure the specified scanning angle again, scan the target scanning angle using the frequency-modulated continuous wave lidar within a second ranging cycle time to obtain a second ranging signal, wherein the second ranging cycle time corresponds to the specified scanning angle; and if the signal-to-noise ratio of the second ranging signal is greater than or equal to a signal-to-noise ratio threshold, perform distance calculation on the second ranging signal to obtain the second ranging result corresponding to the specified scanning angle.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] According to another aspect of the embodiments of this application, a scanning 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.

[0082] 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.

[0083] 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 709, and / or installed from removable medium 711. When the computer program is executed by central processing unit 701, 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.

[0084] Figure 7 This is a computer system architecture block diagram of an optional electronic device according to an embodiment of this application. For example... Figure 7 As shown, the computer system 700 includes a CPU (Central Processing Unit) 701, which can perform various appropriate actions and processes based on programs stored in ROM 702 or programs loaded into RAM 703 from storage section 708. Random access memory 703 also stores various programs and data required for system operation. The CPU 701, ROM 702, and RAM 703 are interconnected via bus 704. An I / O (Input / Output) interface 705 is also connected to bus 704.

[0085] The following components are connected to the I / O interface 705: an input section 706 including a keyboard, mouse, etc.; an output section 707 including a CRT (Cathode Ray Tube), LCD (Liquid Crystal Display), etc., and speakers, etc.; a storage section 708 including a hard disk, etc.; and a communication section 709 including a network interface card such as a LAN card, modem, etc. The communication section 709 performs communication processing via a network such as the Internet. A drive 710 is also connected to the I / O interface 705 as needed. A removable medium 711, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on the drive 710 as needed so that computer programs read from it can be installed into the storage section 708 as needed.

[0086] 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 709, and / or installed from removable medium 711. When the computer program is executed by central processing unit 701, it performs various functions defined in the system of this application.

[0087] It should be noted that, Figure 7 The computer system 700 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.

[0088] 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 described herein, 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.

[0089] 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 ranging method based on frequency-modulated continuous-wave lidar, characterized by, include: When using the frequency-modulated continuous wave lidar to measure distance at a specified scanning angle, during a first ranging period, the frequency-modulated continuous wave lidar is used to scan at least one scanning angle within the specified angle range to obtain at least one ranging signal, wherein the first ranging period corresponds to the specified scanning angle, and the specified angle range includes the specified scanning angle. Distance calculation is performed on the first ranging signal in the at least one ranging signal, and the calculated ranging result is determined as the first ranging result corresponding to the specified scanning angle, wherein the signal-to-noise ratio of the first ranging signal is greater than or equal to the signal-to-noise ratio threshold.

2. The method of claim 1, wherein, The first ranging cycle time is divided into M sub-time periods, where M is a positive integer greater than or equal to 2; During the first ranging period, the frequency-modulated continuous wave lidar is used to scan at least one scanning angle within a specified angle range to obtain at least one ranging signal, including: Within each of the M sub-time periods, the frequency-modulated continuous wave lidar is used to scan a scanning angle within the specified angle range to obtain a ranging signal corresponding to each sub-time period, wherein the at least one ranging signal includes the ranging signal corresponding to each sub-time period.

3. The method of claim 2, wherein, Within each of the M sub-time periods, the frequency-modulated continuous wave lidar is used to scan a scanning angle within the specified angle range to obtain a ranging signal corresponding to each sub-time period, including: Within each sub-time period, the frequency-modulated continuous wave lidar is used to scan a random scanning angle within the specified angle range to obtain a ranging signal corresponding to each sub-time period.

4. The method of claim 2, wherein, Each of the M sub-time periods corresponds to a scanning angle obtained by equally dividing the specified angle range; Within each of the M sub-time periods, the frequency-modulated continuous wave lidar is used to scan a scanning angle within the specified angle range to obtain a ranging signal corresponding to each sub-time period, including: Within each sub-time period, the frequency-modulated continuous wave lidar is used to scan the scanning angle corresponding to each sub-time period to obtain a ranging signal corresponding to each sub-time period.

5. The method of claim 2, wherein, The step of using the frequency-modulated continuous wave lidar to scan at least one scanning angle within a specified angle range during the first ranging period to obtain at least one ranging signal further includes: If the signal-to-noise ratio (SNR) of the ranging signal corresponding to the Nth sub-time period in the M sub-time periods is greater than or equal to the SNR threshold, and the Nth sub-time period is not the last sub-time period of the M sub-time periods, the scanning angle of the frequency-modulated continuous wave lidar is controlled to remain at the scanning angle corresponding to the Nth sub-time period. The scanning angles corresponding to sub-time periods after the Nth sub-time period are all the scanning angles corresponding to the Nth sub-time period. The first ranging signal includes the ranging signal corresponding to the Nth sub-time period and the ranging signal corresponding to the sub-time periods after the Nth sub-time period.

6. The method of claim 1, wherein, After scanning at least one scanning angle within a specified angle range using the frequency-modulated continuous wave lidar during the first ranging period, the method further includes: If, among the at least one ranging signal, the ranging signal with the highest signal-to-noise ratio has a signal-to-noise ratio greater than or equal to the signal-to-noise ratio threshold, then the ranging signal with the highest signal-to-noise ratio is determined as the first ranging signal.

7. The method according to any one of claims 1 to 6, characterized in that, The specified angle range is the angle range obtained by offsetting the specified scanning angle to the left and right by half the scanning angle resolution of the frequency-modulated continuous wave lidar, with the specified scanning angle as the center. The first ranging signal corresponds to the target scanning angle within the specified angle range. After determining the calculated ranging result as the first ranging result corresponding to the specified scanning angle, the method further includes: When the frequency-modulated continuous wave lidar is used to measure the distance to the specified scanning angle again, the frequency-modulated continuous wave lidar is used to scan the target scanning angle during the second ranging cycle to obtain a second ranging signal, wherein the second ranging cycle corresponds to the specified scanning angle. If the signal-to-noise ratio of the second ranging signal is greater than or equal to the signal-to-noise ratio threshold, the distance of the second ranging signal is calculated to obtain a second ranging result corresponding to the specified scanning angle.

8. A ranging system based on frequency modulated continuous wave lidar, characterized in that, include: Control components and frequency-modulated continuous wave lidar; among which, The control unit is configured to, when using the frequency-modulated continuous wave lidar to measure distance at a specified scanning angle, within a first ranging period, scan at least one scanning angle within a specified angle range using the frequency-modulated continuous wave lidar to obtain at least one ranging signal, wherein the first ranging period corresponds to the specified scanning angle, and the specified angle range includes the specified scanning angle; perform distance calculation on the first ranging signal in the at least one ranging signal, and determine the calculated ranging result as the first ranging result corresponding to the specified scanning angle, wherein the signal-to-noise ratio of the first ranging signal is greater than or equal to a signal-to-noise ratio threshold; The frequency-modulated continuous wave lidar is used to perform scanning operations in response to the control of the control unit.

9. The ranging system of claim 8, wherein, The first ranging cycle time is divided into M sub-time periods, where M is a positive integer greater than or equal to 2; the control unit is further configured to use the frequency-modulated continuous wave laser radar to scan a scanning angle within the specified angle range in each of the M sub-time periods to obtain a ranging signal corresponding to each sub-time period, wherein the at least one ranging signal includes a ranging signal corresponding to each sub-time period.

10. The ranging system according to claim 9, characterized in that, The control unit is further configured to, within each sub-time period, use the frequency-modulated continuous wave lidar to scan a random scanning angle within the specified angle range to obtain a ranging signal corresponding to each sub-time period; or... Each of the M sub-time periods corresponds to a scanning angle obtained by equally dividing the specified angle range; the control unit is further configured to use the frequency-modulated continuous wave lidar to scan the scanning angle corresponding to each sub-time period within each sub-time period to obtain a ranging signal corresponding to each sub-time period.

Images