LiDAR Scanning Method, Control Device, and LiDAR

Abstract

The present invention relates to the technical field of lidar, in particular to a lidar scanning method, a control device, and a lidar. Among them, the lidar scanning method includes: performing rotational scanning on the environment where the lidar is located with a preset initial scanning accuracy to obtain scanning data, preprocessing the scanning data within a preset scanning period to determine the degree of change of the environment corresponding to each scanning angle, and adjusting the scanning accuracy at the scanning angle corresponding to the environment in real time according to the degree of change of the environment. The present invention can adaptively adjust the scanning frequency and sampling rate according to the change of the target area environment, so that the lidar can maintain a high scanning accuracy in various complex environments.

Description

Technical Field

[0001] The present invention relates to the technical field of lidar, and in particular to a lidar scanning method, a control device, and a lidar. Background Art

[0002] Lidar is often applied to scenarios such as the autonomous driving system of vehicles and building mapping, which require obtaining the accurate position or speed of an object.

[0003] Existing lidar realizes laser scanning through mechanical rotation to obtain depth images of the object to be measured or the surrounding environment. However, in the research and practice of the prior art, the inventors of the present invention found that some target environments are stable, while some are changing in real time. For stable target environments, if the scanning frequency and sampling rate of the lidar are too high, the device will have too much computing pressure and excessive energy consumption. For target area environments with rapid changes, such as abnormal environments or the presence of fast-moving objects, if the scanning frequency and sampling rate of the lidar are too low, effective scanning data cannot be obtained for accurate mapping. Summary of the Invention

[0004] Based on the problems and disadvantages existing in the above-mentioned prior art, the present invention provides a lidar scanning method, a control device, and a lidar, which can adaptively adjust the scanning frequency and sampling rate according to the change of the target area environment, so that the lidar can maintain a high scanning accuracy in various complex environments.

[0005] An embodiment of the present application provides a lidar scanning method, including:

[0006] A lidar scanning method, including:

[0007] Performing rotational scanning on the environment where the lidar is located with a preset initial scanning accuracy to obtain scanning data;

[0008] Preprocessing the scanning data within a preset scanning period to determine the degree of change of the environment corresponding to each scanning angle;

[0009] According to the degree of change of the environment, the scanning accuracy at the scanning angle corresponding to the environment is adjusted in real time.

[0010] Optionally, the preprocessing the scanning data within a preset scanning period to determine the degree of change of the environment corresponding to each scanning angle includes:

[0011] Within a preset period, calculating the variance of the distance values of multiple sampling points at each scanning angle according to the scanning data, and further calculating the average variance corresponding to the multiple sampling points at each scanning angle;

[0012] Determine the degree of change of the environment corresponding to each scanning angle according to the positive correlation between the preset mean variance and the degree of change.

[0013] Optionally, within the preset period, each of the sampling points corresponds to at least two distance values.

[0014] Optionally, the scanning period is a scanning time period or a scanning rotation period.

[0015] Optionally, the real-time adjustment of the scanning accuracy at the scanning angle corresponding to the environment according to the degree of change of the environment further includes:

[0016] When the degree of change of the environment is less than or equal to a first preset threshold, adjust the scanning accuracy at the scanning angle corresponding to the environment to the initial scanning accuracy;

[0017] When the degree of change of the environment is greater than the first preset threshold, increase the scanning accuracy at the scanning angle corresponding to the environment.

[0018] Optionally, increasing the scanning accuracy at the scanning angle corresponding to the environment includes:

[0019] Reduce the scanning frequency at the scanning angle corresponding to the environment and keep the sampling rate unchanged; or

[0020] Keep the scanning frequency at the scanning angle corresponding to the environment unchanged and increase the sampling rate; or

[0021] Reduce the scanning frequency at the scanning angle corresponding to the environment and increase the sampling rate.

[0022] Optionally, when the degree of change of the environment is greater than the first preset threshold, increasing the scanning accuracy at the scanning angle corresponding to the environment includes:

[0023] When the degree of change of the environment is greater than the first preset threshold and less than or equal to a second preset threshold, keep the scanning frequency at the scanning angle corresponding to the environment unchanged and increase the sampling rate;

[0024] When the degree of change of the environment is greater than the second preset threshold, reduce the scanning frequency at the scanning angle corresponding to the environment and increase the sampling rate.

[0025] Based on the same inventive concept, an embodiment of the present application further provides a lidar scanning device, including a control unit, as well as a processing unit and a scanning unit electrically connected to the control unit;

[0026] The scanning unit is configured to perform rotational scanning on the environment where the lidar is located with a preset initial scanning accuracy to obtain scanning data;

[0027] The processing unit is configured to preprocess the scan data within a preset scan period to determine the degree of change in the environment corresponding to each scan angle;

[0028] The control unit is configured to adjust the scan accuracy at the scan angle corresponding to the environment in real time according to the degree of change in the environment.

[0029] Based on the same inventive concept, an embodiment of the present application further provides a computer storage medium, which is used to store program data. When the program data is executed by a processor, it is used to implement the lidar scanning method as described above.

[0030] Based on the same inventive concept, an embodiment of the present application further provides a lidar, including the computer storage medium as described above.

[0031] One of the above technical solutions has the following advantages and beneficial effects:

[0032] In each embodiment of the present application, the scan data is preprocessed to determine the change information of the target area environment, and then the scan frequency and sampling rate are adaptively adjusted according to the change situation of the target area environment indicated by the change information, so that the lidar can maintain a high scan accuracy in various complex environments. Description of the Drawings

[0033] The present application will describe the embodiments in conjunction with the drawings. The drawings of the present application are only for describing the embodiments and are for display purposes. Without departing from the principles of the present application, those skilled in the art can easily make other embodiments according to the following description.

[0034] Figure 1 It is a schematic flowchart of the lidar scanning method in an embodiment of the present application;

[0035] Figure 2 It is a schematic structural diagram of the lidar scanning control device in an embodiment of the present application. Detailed Embodiments

[0036] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. It can be understood that the specific embodiments described herein are only used to explain the present application, rather than limiting the present application. Additionally, it should be noted that for the sake of description, only parts related to the present application are shown in the drawings rather than all the structures. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0037] The terms "first", "second", etc. in this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally further include steps or units not listed, or may optionally further include other steps or units inherent to these processes, methods, products or devices.

[0038] Referring to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appearing in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0039] The following explains some of the technical terms involved herein to facilitate understanding by those skilled in the art.

[0040] Lidar: Light detection and ranging. Lidar measures parameters such as the distance, azimuth, speed, and attitude of a target object by emitting a laser beam towards the target object and receiving the reflected laser beam, and uses means such as the TOF (Time of Flight) method to detect, track, and identify targets such as obstacles and moving objects.

[0041] Classification is based on the imaging scanning method of Lidar:

[0042] Mechanical rotation type (hybrid solid state): It uses mechanical 360° rotation scanning technology in the horizontal direction and electronic scanning technology in the pitch / vertical direction. Main advantages: high single-point measurement accuracy, strong anti-interference ability, and can withstand high laser power; the disadvantage is that the installation and adjustment workload is large and the structure is complex.

[0043] MEMS (Micro-Electro Mechanical System) type: It uses MEMS micro mirrors to integrate all mechanical components into a single chip and adopts semiconductor manufacturing processes. Advantages: high integration, small size, and low power consumption; chip-level process, suitable for mass production. Disadvantages: difficult to control high-precision high-frequency vibration, high manufacturing precision requirements, and cannot achieve 360° scanning, and needs to be used in combination.

[0044] Solid-State Lidar: Similar to phased array radar, it changes the emission angle of the laser by adjusting the phase difference of each emission unit in the emission array. Advantages: Fast scanning speed (MHz), high scanning accuracy (on the order of μrad), and good controllability.

[0045] In one embodiment, the present application provides a lidar scanning method. Taking the mechanical rotation type as an example, the lidar uses mechanical 360° rotation scanning technology in the horizontal direction and electronic scanning technology in the pitch / vertical direction.

[0046] As Figure 1 shown, the lidar scanning method includes steps S100 - S300.

[0047] Step S100: Perform rotational scanning on the environment where the lidar is located with a preset initial scanning accuracy to obtain scanning data;

[0048] It can be understood that at the moment of starting the scanning, the lidar is controlled to scan the target environment with an initial scanning frequency and an initial sampling rate. During the continuous scanning process, since the lidar is controlled to perform adaptive scanning, the scanning frequency and sampling rate of the lidar at the current moment are related to the change situation of the target environment at the current moment, rather than a fixed scanning frequency or a fixed sampling rate.

[0049] Among them, the target area environment should be understood as the area environment where the lidar performs the scanning action, and the scanning data should be understood as the data related to distance, azimuth, speed, attitude, etc. collected during the process of detecting, tracking, and identifying the target area environment.

[0050] Exemplarily, it can be understood that the scanning data is point cloud data and can be used to calculate the coordinate information of the corresponding points in the target environment.

[0051] Step S200: Preprocess the scanning data within a preset scanning period to determine the degree of change of the environment corresponding to each scanning angle;

[0052] In one embodiment of the present application, the scanning period is a scanning time period or a scanning rotation period.

[0053] In one embodiment, the preprocessing of the scanning data includes calculating the variance of part or all of the scanning data to obtain change information that can indicate whether the target area environment has changed.

[0054] Exemplarily, the scan data includes coordinate information of corresponding points in the target environment, and the distance information from the points to the lidar can be calculated through the coordinate information of the points. The scan data in a certain time interval / laser radar rotation scan interval is intercepted, and the variances of the distance information of several captured points are calculated respectively. For example, when the lidar rotates to the Nth circle, the distance information of K points in the target environment is captured, and when the lidar rotates to the (N + M)th circle, the distance information of K points in the target area is captured. It should be noted that the K points captured in the Nth circle and the K points captured in the (N + M)th circle should be points corresponding to the same target object / target position, or points corresponding to the same azimuth. The change information indicating whether the target area environment has changed is obtained by calculating the variance of the scan data in the interval from the Nth circle to the (N + M)th circle.

[0055] It should be noted that when calculating the scan data in the interval from the Nth circle to the (N + M)th circle, M is set according to specific circumstances. The larger M is, the larger the amount of data to be calculated.

[0056] Variance is a measure of the degree of dispersion when measuring a random variable or a set of data in probability theory and statistical variance, and is used to represent the degree of deviation. The magnitude of the variance calculated according to the above can more accurately judge the magnitude of the change in the target environment.

[0057] In an embodiment of the present application, the step S200 includes:

[0058] Step S210: Within a preset period, calculate the variance of the distance values of multiple sampling points at each scan angle according to the scan data, and then calculate the average variance corresponding to the multiple sampling points at each scan angle;

[0059] In an embodiment of the present application, within the preset period, each of the sampling points corresponds to at least two distance values.

[0060] Step S220: Determine the degree of change of the environment corresponding to each scan angle according to the positive correlation between the preset average variance and the degree of change.

[0061] Step S300: According to the degree of change of the environment, adjust the scanning accuracy at the scanning angle corresponding to the environment in real time.

[0062] It can be understood that by adjusting the scanning frequency and sampling rate in the direction of the local environment, and if the environment in other directions has not changed, the scanning frequency and sampling rate in other directions will be restored to the initial scanning frequency and initial sampling rate, so as to realize the adaptive adjustment of the scanning frequency and sampling rate to meet the precise scanning of the lidar under various changes in the target area environment.

[0063] In an embodiment of the present application, the step S300 further includes:

[0064] Step S310: When the degree of change of the environment is less than or equal to a first preset threshold, adjust the scanning accuracy at the scanning angle corresponding to the environment to the initial scanning accuracy;

[0065] It should be understood that based on the above embodiments, it can be set that when the variance of the scanning data in the interval from the Nth circle to the (N + M)th circle is calculated to be zero or less than a preset value, it is determined that the environment of the target area has not changed. At this time, the current scanning frequency and sampling rate are restored to the initial scanning frequency and initial sampling rate, which can reduce energy consumption on the one hand and reduce the amount of calculation and improve the calculation speed on the other hand.

[0066] In an embodiment of the present application, the step S310 includes:

[0067] Step S311: Reduce the scanning frequency at the scanning angle corresponding to the environment and keep the sampling rate unchanged; or

[0068] Step S312: Keep the scanning frequency at the scanning angle corresponding to the environment unchanged and increase the sampling rate; or

[0069] Step S313: Reduce the scanning frequency at the scanning angle corresponding to the environment and increase the sampling rate.

[0070] Step S320: When the degree of change of the environment is greater than the first preset threshold, increase the scanning accuracy at the scanning angle corresponding to the environment.

[0071] In an embodiment of the present application, the step S320 includes:

[0072] Step S321: When the degree of change of the environment is greater than the first preset threshold and less than or equal to a second preset threshold, keep the scanning frequency at the scanning angle corresponding to the environment unchanged and increase the sampling rate;

[0073] Step S322: When the degree of change of the environment is greater than the second preset threshold, reduce the scanning frequency at the scanning angle corresponding to the environment and increase the sampling rate.

[0074] In the case of adopting the mechanical 360° rotary scanning technology, when a local environment changes, the variance result of the scanning data in the interval from the Nth circle to the (N + M)th circle can accurately indicate that a local environment has changed and the degree of change, and the position information of a local environment can be determined according to the distance information of the corresponding points.

[0075] It can be understood that the first preset threshold and the second preset threshold are related to the threshold values calibrated according to the prior physical size when the lidar adopts the mechanical 360° rotation scanning technology. In addition to accurately defining the degree of change in the target area environment, the first preset threshold and the second preset threshold can also prevent the system from jittering near the threshold value, which affects the scanning effect of the lidar.

[0076] As described above, each embodiment of the present application preprocesses the scanning data to determine the change information of the target area environment, and then adaptively adjusts the scanning frequency and sampling rate according to the change situation of the target area environment indicated by the change information, so that the lidar can maintain a high scanning accuracy in various complex environments.

[0077] As Figure 2 shown, based on the same inventive concept, an embodiment of the present application further provides a lidar scanning control device, including a scanning module 10, a preprocessing module 20, and a control module 30.

[0078] The scanning module 10 is configured to obtain scanning data for scanning the target area environment.

[0079] It can be understood that at the moment of starting the scanning, the lidar is controlled to scan the target environment at the initial scanning frequency and the initial sampling rate. During the continuous scanning process, since the lidar is controlled to perform adaptive scanning, the scanning frequency and sampling rate of the lidar at the current moment are related to the change situation of the target environment at the current moment, rather than a fixed scanning frequency or a fixed sampling rate.

[0080] Among them, the target area environment should be understood as the area environment where the lidar performs the scanning action, and the scanning data should be understood as the data related to distance, azimuth, speed, attitude, etc. collected during the process of detecting, tracking, and identifying the target area environment. Exemplarily, it can be understood that the scanning data is point cloud data, which can be used to calculate the coordinate information of the corresponding points in the target environment.

[0081] The preprocessing module 20 is configured to preprocess the scanning data to determine the change information of the target area environment.

[0082] In one embodiment, the preprocessing module 20 is configured to calculate the variance of part or all of the scanning data to obtain change information that can indicate whether the target area environment has changed.

[0083] Exemplarily, the scan data includes the coordinate information of the corresponding points in the target environment, and the distance information from the points to the lidar can be calculated through the coordinate information of the points. The scan data in a certain time interval / lidar rotation scan interval is intercepted, and the variances of the distance information of several captured points are calculated respectively. For example, when the lidar rotates to the Nth circle, the distance information of K points in the target environment is captured, and when the lidar rotates to the (N + M)th circle, the distance information of K points in the target area is captured. It should be noted that the K points captured in the Nth circle and the K points captured in the (N + M)th circle should be the points corresponding to the same target object / target position, or the points corresponding to the same azimuth. The change information indicating whether the target area environment has changed is obtained by calculating the variance of the scan data in the interval from the Nth circle to the (N + M)th circle.

[0084] It should be noted that when calculating the scan data in the interval from the Nth circle to the (N + M)th circle, M is set according to specific circumstances. The larger M is, the larger the amount of data to be calculated.

[0085] Variance is a measure of the degree of dispersion when measuring a random variable or a set of data in probability theory and statistical variance, and is used to represent the degree of deviation. The size of the variance calculated according to the above can accurately judge the degree of change of the target environment.

[0086] The control module 30 is used to adjust the current scan frequency and sampling rate according to the change information, and use the adjusted scan frequency and sampling rate.

[0087] Exemplarily, the control module 30 is used to restore the current scan frequency and sampling rate to the initial scan frequency and initial sampling rate when it is determined according to the change information that the target area environment has not changed.

[0088] It should be understood that based on the above embodiments, it can be set that when the variance of the scan data in the interval from the Nth circle to the (N + M)th circle is calculated to be zero, or less than a preset value, it is determined that the target area environment has not changed. At this time, restoring the current scan frequency and sampling rate to the initial scan frequency and initial sampling rate can, on the one hand, reduce energy consumption, and on the other hand, reduce the amount of calculation and improve the calculation speed.

[0089] Exemplarily, the control module 30 is further used to determine the position information and the corresponding degree of change of at least one local environment that has changed in the target area environment when it is determined according to the change information that the target area environment has changed; and adjust the scan frequency and sampling rate in the direction where the local environment is located according to the position information and the corresponding degree of change of the local environment.

[0090] In the case of adopting the mechanical 360° rotation scanning technology, when a local environment changes, calculating the variance result of the scanning data in the interval from the Nth circle to the (N + M)th circle can accurately indicate the change and the degree of change of a local environment, and determine the position information of a local environment according to the distance information of the corresponding points.

[0091] It can be understood that by adjusting the scanning frequency and sampling rate in the direction where the local environment is located, and since the environments in other directions remain unchanged, the scanning frequency and sampling rate in other directions will be restored to the initial scanning frequency and initial sampling rate, thereby realizing the adaptive adjustment of the scanning frequency and sampling rate to meet the precise scanning of the lidar under various changes in the target area environment.

[0092] Exemplarily, the control module 30 determines that if the degree of change of the local environment is less than or equal to the first preset threshold, the current scanning frequency and sampling rate will be restored to the initial scanning frequency and initial sampling rate.

[0093] The control module 30 determines that if the degree of change of the local environment is less than or equal to the second preset threshold and greater than the first preset threshold, the current scanning frequency remains unchanged and the current sampling rate is increased.

[0094] The control module 30 determines that if the degree of change of the local environment is greater than the second preset threshold, the current scanning frequency is decreased and the sampling rate is increased.

[0095] It can be understood that the first preset threshold and the second preset threshold are related to the threshold values calibrated according to the prior physical size when the lidar adopts the mechanical 360° rotation scanning technology. In addition to accurately defining the degree of change of the target area environment, the first preset threshold and the second preset threshold can also prevent the system from jittering near the threshold values, which affects the scanning effect of the lidar.

[0096] In summary, through preprocessing the scanning data in the embodiments of the present application to determine the change information of the target area environment, and then adaptively adjusting the scanning frequency and sampling rate according to the change situation of the target area environment indicated by the change information, the lidar can maintain a high scanning accuracy in various complex environments.

[0097] Based on the same inventive concept, an embodiment of the present application also provides a lidar that performs scanning by applying the above-mentioned lidar scanning method.

[0098] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A lidar scanning method, characterized in that, Including: Performing rotational scanning on the environment where the lidar is located at a preset initial scanning accuracy to obtain scanning data; Preprocessing the scanning data within a preset scanning period to determine the degree of environmental change corresponding to each scanning angle; According to the degree of environmental change, adjusting the scanning accuracy at the scanning angle corresponding to the environment in real time; Among them, the preprocessing the scanning data within a preset scanning period to determine the degree of environmental change corresponding to each scanning angle includes: Within a preset period, calculating the variance of the distance values for multiple sampling points at each scanning angle based on the scanning data, and then calculating the average variance corresponding to the multiple sampling points at each scanning angle; Determining the degree of environmental change corresponding to each scanning angle according to the positive correlation between the preset average variance and the degree of change.

2. The lidar scanning method according to claim 1, wherein Within the preset period, each of the sampling points corresponds to at least two distance values.

3. The lidar scanning method according to any one of claims 1-2, characterized in that, The scanning period is a scanning time period or a scanning rotation period.

4. The lidar scanning method according to claim 1, wherein The adjusting the scanning accuracy at the scanning angle corresponding to the environment in real time according to the degree of environmental change further includes: When the degree of environmental change is less than or equal to a first preset threshold, adjusting the scanning accuracy at the scanning angle corresponding to the environment to the initial scanning accuracy; When the degree of environmental change is greater than the first preset threshold, increasing the scanning accuracy at the scanning angle corresponding to the environment.

5. The lidar scanning method according to claim 4, wherein The increasing the scanning accuracy at the scanning angle corresponding to the environment includes: Reducing the scanning frequency at the scanning angle corresponding to the environment and keeping the sampling rate unchanged; or Keeping the scanning frequency at the scanning angle corresponding to the environment unchanged and increasing the sampling rate; or Reducing the scanning frequency at the scanning angle corresponding to the environment and increasing the sampling rate.

6. The lidar scanning method according to claim 3, wherein When the degree of environmental change is greater than the first preset threshold, increasing the scanning accuracy at the scanning angle corresponding to the environment includes: When the degree of environmental change is greater than the first preset threshold and less than or equal to a second preset threshold, keeping the scanning frequency at the scanning angle corresponding to the environment unchanged and increasing the sampling rate; When the degree of environmental change is greater than the second preset threshold, reducing the scanning frequency at the scanning angle corresponding to the environment and increasing the sampling rate.

7. A lidar scanning device, characterized in that, Including a control unit, as well as a processing unit and a scanning unit electrically connected to the control unit; The scanning unit is configured to perform rotational scanning on the environment where the lidar is located at a preset initial scanning accuracy to obtain scanning data; The processing unit is configured to preprocess the scanning data within a preset scanning period to determine the degree of environmental change corresponding to each scanning angle; The control unit is configured to adjust the scanning accuracy at the scanning angle corresponding to the environment in real time according to the degree of environmental change; Among them, the processing unit is specifically configured to: within a preset period, calculate the variance of the distance values for multiple sampling points at each scanning angle based on the scanning data, and then calculate the average variance corresponding to the multiple sampling points at each scanning angle; determine the degree of environmental change corresponding to each scanning angle according to the positive correlation between the preset average variance and the degree of change.

8. A computer storage medium, characterized in that, The computer storage medium is used for storing program data, and when the program data is executed by a processor, it is used to implement the lidar scanning method according to any one of claims 1-6.

9. A lidar, characterized in that, It includes the computer storage medium according to claim 8.

Images