Laser radar detection method and detection device

Abstract

The present application provides a detection method and detection device of a laser radar, the method comprising: a transmitting module outputs two adjacent detection lasers with a preset delay time; a scanning module receives the detection laser and emits the detection laser to a preset area, the scanning module scans the preset area using a preset scanning mode corresponding to the preset area, the scanning module also receives the echo laser reflected from the preset area, and outputs the echo laser; the receiving detection module receives the echo laser and converts it into an electrical signal; the signal acquisition and processing module acquires the electrical signal, and processes the electrical signal to obtain the detection information of the preset area. The present application obtains more point cloud information in the preset area, improves the scanning resolution capability of the laser radar for the preset area, and improves the detection capability of the laser radar in different application scenarios.

Description

Technical Field

[0001] This application belongs to the technical field of lidar detection, and particularly relates to a detection method and a detection device for a lidar. Background Art

[0002] Currently, lidars are used in the fields of intelligent transportation, autonomous driving, assisted driving, navigation, mapping, meteorology, aerospace, robotics, etc. For each frame of detection light emitted by the scanning module of a traditional semi-solid lidar, after the scanning working mode of the lidar is determined, the lidar can only adopt a fixed scanning resolution for the same scanning area, resulting in poor flexibility of the laser scanning of the lidar, insufficient scanning resolution ability, and inability to meet the detection requirements of different application scenarios.

[0003] For different application scenarios, the existing lidars have problems of insufficient scanning resolution ability and insufficient detection ability in each application scenario. Summary of the Invention

[0004] The embodiments of this application provide a detection method and a detection device for a lidar, which solve the problem of insufficient scanning resolution ability of the lidar in each application scenario, thereby resulting in insufficient detection ability.

[0005] The first aspect of the embodiments of this application provides a detection method for a lidar, including:

[0006] The emission module outputs adjacent two detection lasers with a preset delay time;

[0007] The scanning module accesses the detection laser, emits the detection laser to a preset area, the scanning module scans the preset area with a preset scanning mode corresponding to the preset area, the scanning module also receives the echo laser reflected from the preset area, and outputs the echo laser;

[0008] The receiving and detecting module receives the echo laser and converts it into an electrical signal;

[0009] The signal acquisition and processing module acquires the electrical signal and processes the electrical signal to obtain the detection information of the preset area.

[0010] In one of the embodiments, the scanning direction of the scanning module includes at least one of a first scanning direction and a second scanning direction, the first scanning direction and the second scanning direction form a preset angle, and the preset angle is less than or equal to 180 degrees;

[0011] The scanning module scans the preset area with a preset scanning mode corresponding to the preset area, and further includes:

[0012] The scanning module scans the preset area in the first scanning direction by using the preset scanning mode corresponding to the preset area; or

[0013] The scanning module scans the preset area in the second scanning direction by using the preset scanning mode corresponding to the preset area.

[0014] In one embodiment, the preset area includes at least one preset sub-area;

[0015] Before the emitting module outputs the detection laser twice at a preset delay time, the detection method includes:

[0016] The lidar acquires the scanning area corresponding to the detection field of view angle of the scanning module;

[0017] The lidar acquires the preset sub-area where the scanning area is located;

[0018] The lidar acquires the scanning density corresponding to the preset sub-area;

[0019] The lidar controls the emitting module to output the detection laser at a preset delay time corresponding to the scanning density based on the scanning density.

[0020] In one embodiment, the scanning module scans the preset area by using the preset scanning mode corresponding to the preset area, including:

[0021] The scanning module acquires the preset scanning mode corresponding to the scanning density;

[0022] The scanning module scans the preset sub-area by using the preset scanning mode.

[0023] In one embodiment, the preset scanning mode is to scan the preset sub-area by using the inter-group interval of the scanning group corresponding to the preset sub-area, the scanning group is N scanning lines formed by the detection laser emitted by the emitting module at one time, and the inter-group interval is the inter-group interval angle between two adjacent scans of the scanning group;

[0024] The calculation formula of the inter-group interval is:

[0025]

[0026] Wherein, δβ is the inter-group interval;

[0027] δθ is the interval angle between the scanning lines in the scanning group;

[0028] N is the number of scanning lines in each scanning group, and N is an integer;

[0029] n is the multiple of the scanning line encryption corresponding to the preset sub-region, and n is a real number and n≥0.

[0030] In one embodiment, the preset scanning mode further includes scanning the preset sub-region at the scanning speed of the scanning group corresponding to the preset sub-region, and determining the scanning speed corresponding to the preset sub-region based on the preset delay time, the inter-group interval, and the preset delay time and the inter-group interval. Wherein, the scanning group is N scanning lines formed by the detection laser emitted by the emission module at one time, N is an integer, and the inter-group interval is the inter-group interval angle between two adjacent emissions of the scanning group.

[0031] In one embodiment, the calculation formula of the inter-group interval is further:

[0032]

[0033] Wherein, δβ is the inter-group interval;

[0034] α period is the angle scanned by the scanning group in one scanning period in the second scanning direction;

[0035] α FOV is the detection field of view angle in the second scanning direction, and α period >α FOV ;

[0036] ω 1 is the first scanning speed in the first scanning direction;

[0037] ω 2 is the second scanning speed in the second scanning direction.

[0038] In one embodiment, the emission module includes at least one emission group;

[0039] The emission module outputs adjacent detection lasers with a preset delay time, including:

[0040] The same emission group of the emission module outputs adjacent detection lasers with the preset delay time; or

[0041] Each emission group of the emission module outputs adjacent detection lasers with the preset delay time.

[0042] In a second aspect, an embodiment of the present application provides a detection device for a lidar, including:

[0043] An emission module for the emission module to output adjacent detection lasers with a preset delay time;

[0044] A transmitting optical path module for accessing the detection laser and outputting the detection laser;

[0045] A scanning module for accessing the detection laser, emitting the detection laser to a preset area, scanning the preset area in a preset scanning mode corresponding to the preset area, receiving the echo laser reflected from the preset area by the scanning module, and outputting the echo laser;

[0046] A receiving detection module for receiving the echo laser and converting it into an electrical signal;

[0047] A signal acquisition and processing module for acquiring the electrical signal and processing the electrical signal to obtain detection information of the preset area.

[0048] In one embodiment, the transmitting optical path module includes a coaxial first lens, a second lens, and a third lens;

[0049] The first lens accesses the detection laser output by the transmitting module and converts the detection laser in the horizontal emission direction into parallel light;

[0050] The second lens accesses the parallel light, transmits the parallel light to the third lens, and the second lens also refracts the detection laser in the vertical emission direction to the third lens;

[0051] The third lens accesses the parallel light and transmits it to the scanning module, and the third lens also converts the detection laser in the vertical emission direction into collimated laser and transmits it to the scanning module;

[0052] Wherein, the second lens and the third lens form a long focal length optical path;

[0053] The equivalent focal length of the long focal length optical path is greater than or equal to 50 mm.

[0054] It can be understood that the beneficial effects of the second aspect above can be referred to the relevant descriptions in the first aspect above, and will not be elaborated here.

[0055] The beneficial effects of the embodiments of the present application compared with the prior art are:

[0056] Embodiments of the present application provide a detection method and a detection device for a lidar. The emission module outputs adjacent detection lasers twice with a preset delay time, scans a preset area according to a preset scanning mode corresponding to the preset area for different application scenarios, the scanning module also receives the echo laser reflected from the preset area and outputs the echo laser, the receiving detection module receives the echo laser and converts it into an electrical signal, and the signal acquisition and processing module acquires the electrical signal and processes the electrical signal to obtain the detection information of the preset area, so as to obtain a high-density scanned point cloud of the preset area, obtain more point cloud detection information, thereby improving the scanning resolution of the lidar for the preset area, enhancing the scanning flexibility of the lidar for different preset areas, and further enhancing the detection ability of the lidar in different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0058] Figure 1 is a schematic flowchart of a detection method for a lidar provided by an embodiment of the present application;

[0059] Figure 2 is a schematic diagram of a scanning mode with a fixed step size of a lidar provided by an embodiment of the present application;

[0060] Figure 3 is a schematic flowchart of a detection method before the emission module outputs adjacent detection lasers twice with a preset delay time provided by an embodiment of the present application;

[0061] Figure 4 is a schematic flowchart of the scanning module scanning a preset area according to a preset scanning mode corresponding to the preset area provided by an embodiment of the present application;

[0062] Figure 5 is a schematic diagram of a scanning module obtaining a preset scanning mode corresponding to a scanning density provided by an embodiment of the present application;

[0063] Figure 6-1 is a schematic diagram of the emitter arrangement of an emission board provided by an embodiment of the present application;

[0064] Figure 6-2 is a schematic diagram of the emitter arrangement of an emission board provided by another embodiment of the present application;

[0065] Figure 7-1It is a schematic diagram of the cross-section of an irregular rotating mirror provided by an embodiment of the present application;

[0066] Figure 7-2 It is a schematic diagram of the field of view angle of an irregular rotating mirror provided by an embodiment of the present application;

[0067] Figure 7-3 It is a schematic diagram of the cross-section of a regular rotating mirror provided by another embodiment of the present application;

[0068] Figure 7-4 It is a schematic diagram of the field of view angle of a regular rotating mirror provided by another embodiment of the present application;

[0069] Figure 8 It is a schematic diagram of a process in which a scanning module in an embodiment of the present application accesses a detection laser, emits the detection laser to a preset area, and the scanning module scans the preset area using a preset scanning mode corresponding to the preset area;

[0070] Figure 9 It is another schematic diagram of a process in which a scanning module in an embodiment of the present application accesses a detection laser, emits the detection laser to a preset area, and the scanning module scans the preset area using a preset scanning mode corresponding to the preset area;

[0071] Figure 10 It is a schematic diagram of the structure of a lidar provided by an embodiment of the present application;

[0072] Figure 11 It is a schematic diagram of the structure of the emission optical path module of a lidar provided by an embodiment of the present application;

[0073] Figure 12 It is a schematic diagram of the structure of the scanning module of a lidar provided by an embodiment of the present application. Detailed implementation manners

[0074] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are put forward in order to thoroughly understand the embodiments of the present application. However, those skilled in the art should understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, modules, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0075] It should be understood that when used in the specification and appended claims of the present application, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0076] It should also be understood that the term "and / or" used in the specification and appended claims of this application refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0077] In addition, in the description of the specification and appended claims of this application, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0078] The reference to "one embodiment" or "some embodiments" etc. described in the specification of this application means that a specific feature, structure or characteristic described in connection with the embodiment is included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments" etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0079] The technical solution of this application will be described below through specific embodiments.

[0080] Since lidar needs to adapt to various application scenarios, the ranging ranges of current various lidars are about 200m (at 10% reflectivity), and the number of lines is mainly 128 lines. For different application scenarios, after the scanning working mode of the lidar is determined, for each frame of detection light emitted by the scanning module of the traditional semi-solid state lidar, the lidar can only adopt a fixed scanning resolution for the same area, resulting in relatively poor laser scanning flexibility of the lidar, insufficient scanning resolution ability, inability to meet the detection requirements of different application scenarios, and insufficient to support the lidar to fully detect the surrounding environment, and it is necessary to further improve the detection ability of the lidar in different application scenarios.

[0081] To solve the problems of insufficient scanning resolution and insufficient detection capabilities in various application scenarios of lidar, the detection method according to the embodiments of the present application outputs detection lasers twice in succession with a preset delay time through a transmitting module, scans a preset area according to a preset scanning mode corresponding to the preset area in different application scenarios, the scanning module also receives the echo laser reflected from the preset area and outputs the echo laser, the receiving detection module receives the echo laser and converts it into an electrical signal, and the signal acquisition and processing module acquires the electrical signal and processes the electrical signal to obtain the detection information of the preset area, so as to obtain a high-density scanned point cloud of the preset area and obtain more point cloud detection information, thereby improving the scanning resolution of the lidar for each preset area, enhancing the scanning flexibility of the lidar for different preset areas, and further enhancing the detection capabilities of the lidar in different application scenarios.

[0082] It should be noted that the preset area is the area corresponding to the detection field of view of the lidar. The preset area scanned by the laser can also be referred to as the field of view (FOV), which refers to the scanning range that the lidar can cover. Among them, the scanning directions of the scanning module include a first scanning direction and a second scanning direction. The first scanning direction and the second scanning direction form a preset angle, and the preset angle is less than or equal to 180 degrees. The scanning in both scanning directions is independently controlled. For example, the first scanning direction is a vertical scan (also called column scan) in the up-and-down direction relative to the target object, and the second scanning direction is a horizontal scan (also called row scan) in the left-and-right direction relative to the target object in the preset area. At this time, the preset angle formed by the first scanning direction and the second scanning direction is 90°. The preset angle formed by the two scanning directions is set according to the needs of the lidar. For example, it can also be 30°, 60°, 120°, and 150°.

[0083] The scanning device in the first direction can be, for example, any one of a galvanometer mirror, a one-dimensional galvanometer, and a rotating platform. The scanning device in the second direction can also be, for example, any one of a galvanometer mirror, a one-dimensional galvanometer, and a rotating platform. The present application does not limit the type of the scanning device in any of the two scanning directions. It can be understood that the types of the scanning devices in the first scanning direction and the second scanning direction can be the same or different, and the present application does not make any restrictions. As a preferred embodiment, the scanning devices in the two scanning directions can be independently controlled.

[0084] The Region Of Interest (ROI) refers to the area that needs to be focused on in the preset area scanned by the lidar. In the embodiments of the present application, the preset area may include at least one preset sub-area. As an alternative embodiment, when the preset area may include multiple preset sub-areas. For example, the preset area includes at least two preset sub-areas. For instance, it can be 2, 3, 4, 5, etc. The embodiments of the present application do not limit the number of preset sub-areas included in the preset area. It can be understood that multiple preset sub-areas may partially be in the ROI of the radar and partially be in other areas outside the ROI of the radar, that is, the general detection area.

[0085] It should be noted that the ROI is the area that the radar pays more attention to, and the user can set the target detection according to their own needs. Usually, the scanning resolution requirement for the ROI is relatively high, and the corresponding scanning lines are relatively denser, that is, the scanning density is high, while the scanning resolution requirement for other areas (general detection area) of the lidar detection field of view outside the ROI is relatively low, and the corresponding scanning lines are relatively sparser, that is, the scanning density is low.

[0086] It should be noted that the angular range of the detection field of view corresponding to the preset area of the lidar includes the angular range of the horizontal detection field of view and the angular range of the vertical detection field of view. The vertical detection field of view corresponds to the vertical scan (also called column scan) in the up and down direction relative to the target object, and the horizontal detection field of view corresponds to the horizontal scan (also called row scan) in the left and right direction relative to the target object.

[0087] In one embodiment, the angular range of the horizontal detection field of view of the detection field of view of the lidar is -60° to 60°, and the angular range of the vertical detection field of view of the detection field of view of the lidar is -12.5° to 12.5°. In this embodiment, no specific limitations are imposed on the upper and lower limits of the angular range. For example, the angular range of the horizontal detection field of view of the detection field of view can also be various angular ranges such as -30° to 30°, -45° to 45°, and -75° to 75°, and the angular range of the vertical detection field of view of the detection field of view can also be various angular ranges such as -10° to 10°, -15° to 15°, -20° to 20°, and -30° to 30°. The upper and lower limits of the angular range are set according to the maximum detection range that the scanning module of the lidar can perform.

[0088] It should be noted that the field of view angle corresponding to a complete scan by the scanning module is greater than or equal to the total detection field of view angle of the radar. And the field of view angle corresponding to each step of the radar scanning module is less than or equal to the total detection field of view angle of the radar, and the specific angular range of the field of view angle corresponding to each step of the scanning module is set according to the specific requirements of the scanning resolution of the scanning module, and no limitation is imposed in this embodiment.

[0089] As Figure 1 shown, the first aspect of the embodiment of the present application provides a detection method for a lidar, including:

[0090] S100, the emission module outputs detection lasers twice in succession with a preset delay time.

[0091] In one embodiment, the emission module includes at least one emission group, that is, the emission module can include one emission group or multiple emission groups. The emission module outputs detection lasers twice in succession with a preset delay time, including:

[0092] The same emission group of the emission module outputs detection lasers twice in succession with a preset delay time; or

[0093] Each emission group of the emission module outputs detection lasers twice in succession with a preset delay time.

[0094] Wherein, the preset delay time is the time interval between two consecutive emissions of detection lasers by the same emission group, or the preset delay time is the time interval corresponding to two consecutive emissions of detection lasers by different emission groups.

[0095] Since the same emission group outputs detection lasers twice in succession with a preset delay time, or each emission group outputs detection lasers twice in succession with a preset delay time, the scanning resolution of the lidar can be adjusted by controlling the time interval between two consecutive emissions of the emission module and the scanning step amount of the scanning module according to the scanning resolution requirements of the lidar. Among them, when the same preset delay time is set and the emission module includes multiple emission groups, the scanning lines of the detection lasers emitted to the preset area each time will be more and denser, so that more echo lasers in the preset area can be obtained, and then a higher density of scanning point clouds in the preset area can be obtained, more point cloud detection information can be obtained, the scanning resolution ability of the lidar for the preset area is improved, the scanning flexibility of the lidar for different preset areas is enhanced, and the detection ability of the lidar in different application scenarios is enhanced. The number of emission groups of the emission module and the number of lasers included in each emission group are not specifically limited in this embodiment and are set according to the detection performance requirements of the lidar.

[0096] In one embodiment, the emission group includes a transmitter, which can be a Vertical-Cavity Surface-Emitting Laser (VCSEL) or an Edge Emitting Laser (EEL). Optionally, it can also be fiber laser light output, and an output array is formed through a specific beam splitting method. The type of the transmitter is not limited in this embodiment. It can be understood that multiple emission groups can be arranged in a column or in multiple columns, and the specific arrangement of multiple emission groups is not limited in this embodiment. As an optional embodiment, the physical spacing distances in the transverse and longitudinal directions of the lasers in multiple emission groups can be equal or unequal. The physical spacing distance is not specifically limited in this embodiment, and the physical spacing distances of the lasers are set according to the scanning requirements of the lidar.

[0097] In one embodiment, the emission module outputs detection lasers at adjacent times with a preset delay time, that is, after the emission module outputs a detection laser, when the interval time is the preset delay time T0, it outputs a detection laser again. Each time the detection laser is emitted, a scan group is formed. The scan group is N scan lines formed by the detection lasers emitted by the emission module once, and N is an integer. In addition, the inter-group interval angle between the scan groups emitted by the emission module adjacent twice is also called the inter-group interval. As an optional embodiment of the present application, when the lidar includes two scanning directions and the interval of the scan lines can be realized by the scanning of a scanning device in one dimension direction, the inter-group interval is also called the step size of the scanning device.

[0098] It should be noted that when controlling the emission module to output detection lasers with a preset delay time T 0 the power of the detection lasers output by the emission module within the preset delay time T 0 can be variably powered or output with a constant power according to the requirements of lidar scanning, without specific limitation. In one embodiment, the power of the detection lasers output by one emission group or multiple emission groups within the preset delay time T 0 is output with a constant power.

[0099] Such as Figure 2As shown, when the transmitting module outputs the detection laser twice at a fixed time interval, in the figure, the same line type represents 8 detection laser scan lines output by the transmitting module of the lidar at one time to form a scan group. Four line types indicate that the transmitting module has successively output four groups of detection lasers, namely A, B, C, and D. The scan group performs vertical scanning according to a fixed scanning mode (i.e., a fixed scanning speed and a fixed scanning step size). The number of scan lines in each scan group is 8, and the interval angle between the scan lines is δθ. At time t1, the A scan group outputs 8 detection laser scan lines of group A from top to bottom at a fixed frequency, and the scanning module continues to scan downward with a fixed step size of 8×δθ; when the scanning module completes the fixed step size of 8×δθ at time t2, the B scan group outputs 8 detection laser scan lines of group B from top to bottom and continues to scan; when the scanning module completes the fixed step size of 8×δθ at time t3, the C scan group outputs 8 detection laser scan lines of group C from top to bottom and continues to scan until the scanning of the entire space area is formed, and scan lines with a resolution of δθ are formed in the entire space. The delay time between when the scanning module starts from time t1 and when it completes the fixed step size of 8×δθ at time t2, or the delay time between when the scanning module starts from time t2 and when it completes the fixed step size of 8×δθ at time t3, is both a fixed delay time T. It can be understood that when the transmitting module scans at a fixed time interval and the scanning module scans in a fixed scanning mode, a scanning field of view with uniform scanning density can be formed.

[0100] In one embodiment, when the preset area includes at least one preset sub-area, that is, when the preset area includes one or more preset sub-areas, and the scanning density of each preset sub-area is different, that is, when the scanning field of view is non-uniform, as Figure 3 shown, before the transmitting module outputs the detection laser twice at a preset delay time, the detection method further includes:

[0101] S110, the lidar obtains the scanning area corresponding to the detection field of view angle of the scanning module.

[0102] S120, the lidar obtains the preset sub-area where the scanning area is located.

[0103] S130, the lidar obtains the scanning density corresponding to the preset sub-area.

[0104] S140, the lidar controls the transmitting module to output the detection laser at the preset delay time corresponding to the scanning density based on the scanning density.

[0105] Among them, since the preset area includes at least one preset sub-area, before the lidar outputs the detection laser in the scanning module, it first obtains the scanning area corresponding to the detection field of view angle of the scanning module, and then obtains the preset sub-area of the total detection field of view of the lidar where the scanning area is located, and obtains the scanning density corresponding to the preset sub-area. Thus, the lidar controls the emission module to output the detection laser at the preset delay time corresponding to the scanning density of the preset sub-area based on the obtained scanning density of the preset sub-area. Therefore, the lidar scans the preset sub-area with the preset delay time corresponding to the scanning density based on the scanning density required by the preset sub-area's scanning resolution, thereby improving the flexibility of the lidar to scan the preset area. For multiple preset sub-areas of the preset area, the scanning density of each preset sub-area can be equal or different, and the scanning densities of multiple preset sub-areas can be partially equal. Specifically, the scanning density of the preset sub-area is set according to the detection requirements of the lidar.

[0106] S200. The scanning module accesses the detection laser, emits the detection laser to the preset area, the scanning module scans the preset area using a preset scanning mode corresponding to the preset area, the scanning module also receives the echo laser reflected from the preset area, and outputs the echo laser.

[0107] The scanning module scans the preset area using a preset scanning mode corresponding to the preset area, and can scan using different preset scanning modes according to the scanning resolution requirements of the preset area, improving the flexibility of the lidar to use different scanning resolutions for different preset areas, and enhancing the detection ability of the lidar in different application scenarios.

[0108] In one embodiment, as Figure 4 shown, the scanning module scans the preset area using a preset scanning mode corresponding to the preset area, including:

[0109] S210. The scanning module obtains the preset scanning mode corresponding to the scanning density.

[0110] As Figure 5 shown, since the scanning density is manifested as the superposition degree of the scanning lines of each scanning group in the preset sub-area. For example, the preset sub-area 61 is the partial superposition of the scanning lines of scanning group A and scanning group B, the preset sub-area 63 is the partial superposition of the scanning lines of scanning group C and scanning group D. The scanning lines of the preset sub-area 61 and the preset sub-area 63 are relatively sparse, and the scanning density is low, while the preset sub-area 62 is the area where scanning groups A, B, C, and D are superposed with each other, and the scanning lines of the preset sub-area 62 are relatively dense, and the scanning density is high. It shows that the preset sub-area 62 is the area of interest, and the preset sub-areas 61 and 63 are secondary areas of interest. The scanning module obtains the preset scanning mode corresponding to the high scanning density, or obtains the preset scanning mode with low scanning density.

[0111] Specifically, the scanning density is expressed as the number of scanning lines in a preset area. It can be understood that the number of scanning lines in the preset area can be the number of scanning lines formed by the superposition of the scanning lines of multiple scanning groups. Calculate the quotient of the number of scanning lines X in the preset area and the number of scanning lines N in each emission group to obtain the scanning density of the preset area (i.e., the point cloud encryption multiple or the scanning line encryption multiple of the preset area) n = X / N.

[0112] S200, the scanning module scans the preset sub-area in a preset scanning mode.

[0113] The scanning module scans the preset sub-area in a preset scanning mode corresponding to the scanning density of the preset sub-area. By scanning according to the targeted preset scanning mode based on the scanning density of each preset sub-area, the flexibility of controlling the scanning resolution of the lidar is improved, thus adapting to the requirements of different application scenarios.

[0114] In one embodiment, as Figure 5 shown, after obtaining the preset scanning mode corresponding to the scanning density, the scanning module scans the preset sub-area 62 in the preset scanning mode with a high scanning density, and the scanning module scans the preset sub-areas 61 and 63 in the preset scanning mode with a low scanning density.

[0115] It can be understood that the higher the scanning density, the smaller the interval between groups of the scanning group, and the faster the stepping speed of the scanning module; the lower the scanning density, the larger the interval between groups of the scanning group, and the slower the stepping speed of the scanning module.

[0116] In one embodiment, the preset scanning mode is to scan the preset sub-area with the interval between groups of the scanning group corresponding to the preset sub-area, and the calculation formula for the interval between groups of the scanning group is:

[0117]

[0118] where δβ is the interval between groups;

[0119] δθ is the interval angle between each scanning line in the scanning group;

[0120] N is the number of scanning lines in each scanning group, and N is an integer;

[0121] n is the multiple of the scanning line encryption corresponding to the preset sub-area, n is an integer and n ≥ 0.

[0122] As Figure 2As shown, since the number of scan lines N in each scan group is 8 and the angular interval between the scan lines in the scan group is δθ, and since each scan group emits the outgoing laser for the next scan only after the previous scan group has completed its scan, it is assumed that the multiple n of the scan line encryption corresponding to the preset sub-region is 1. Then, the inter-group interval δβ of each scan group in the figure is 8×δθ, and the preset sub-region in the figure is the general detection region.

[0123] As Figure 5 shown, there are four scan groups. Since the number of scan lines N in each scan group is 8 and the angular interval between the scan lines in the scan group is δθ, if the multiple n of the scan line encryption corresponding to the preset sub-region 62 is set to 2, then the inter-group interval The improvement of the scan density is achieved by controlling the cooperation between the two emission times of the emission module and the step size of the scan module.

[0124] Among them, it can be understood that the angular interval δθ between the scan lines in the scan group can be achieved by setting the interval of the emitter arrangement, or by controlling the interval emission of the lasers in some areas or all areas. It should be noted that the scan line interval δθ can be achieved by means not limited to the above description. Among them, it can be understood that the same emission group can be arranged in a column or in different columns. It can be understood that when the same emission group is arranged in two columns, as Figure 6-1 shown, all the emitters in the same emission group can be arranged in a staggered manner, which can reduce δθ. Optionally, the emitters can also be arranged in a staggered manner in some areas to reduce δθ in the target area. Through this design, the point cloud density in the target area can be further improved without changing the settings of the scanning device. Among them, it can be understood that when the emitters of the same emission group are arranged in a column, the interval between the edges of the emitters and the interval in the central area can also be set to be unequal, so as to make the point cloud in the target area denser. As Figure 6-2 shown, the interval between the edge emitters in the same emission group is δθ1, and the interval between the central emitters is δθ2, where δθ1≥δθ2.

[0125] It can be understood that the scanning speed of the scanning module is determined by setting the preset delay time and the inter-group interval. When the step size is the same, that is, the longer the preset delay time, the faster the scanning speed, and the shorter the preset delay time, the slower the scanning speed. Generally speaking, when the scanning module has the same step size, the slower the scanning speed of the scanning module of the lidar, the higher the scanning resolution, and the more detection information is obtained. The faster the scanning speed of the lidar, the lower the scanning resolution, and the less detection information is obtained.

[0126] In another embodiment, the preset scanning mode further scans the preset sub-region at the scanning speed of the scanning group corresponding to the preset sub-region. Among them, the preset region can be classified according to the scanning density corresponding to the preset sub-region to determine that the preset sub-region is the target region of interest, the secondary region of interest or the general region of interest. The scanning step size and the step time of the scanning module are set according to the scanning density of different preset sub-regions, and the scanning speed of the scanning module in different regions is controlled. Among them, by setting the scanning step size and the step time of the scanning module for each level of region, different scanning speeds can be used to scan the preset sub-region of the target region of interest, the preset sub-region of the secondary region of interest, and the preset sub-region of the general detection region. For example, as a preferred embodiment, a uniform speed scanning with an appropriate speed is used for the preset sub-region of the target region of interest, and the scanning speed is gradually increased for the preset sub-region of the secondary region of interest and the general detection region. Therefore, multiple scanning speeds can be used to scan according to the interest situation of the preset sub-region, so that the detection situation of the region of interest can be obtained to the greatest extent, and the detection efficiency of the lidar is improved.

[0127] Since the scanning direction of the scanning module includes the first scanning direction (i.e., the vertical scanning direction) and the second scanning direction (i.e., the horizontal scanning direction), it can be understood that when the scanning of the entire horizontal detection field of view and the vertical detection field of view is completed simultaneously, it is called a scanning cycle. It can be understood that when the scanning device in the first direction is used as the step size implementation device, the scanning cycle of completing one scan can be controlled by controlling the scanning time of the scanning device in the second direction. The scanning cycle of one scan is equal to the preset delay of two transmissions and is also equal to the time for the scanning device in the first dimension to complete one step.

[0128] In one embodiment, during a scanning cycle in the second scanning direction, the scanning group of the scanning module scans an angle of α period , and the horizontal detection field of view angle in the second scanning direction is α FOV , and at this time, there is α period ≧α FOV . In yet another embodiment, when the first direction is used as the step size implementation device, the inter-group interval δβ can be obtained through the scanning field of view angle of the scanning plane in the second scanning direction and the scanning speed of the second scanning plane. Among them, ideally, the calculation formula for the inter-group interval is also:

[0129]

[0130] Among them, δβ is the inter-group interval;

[0131] α period is the angle scanned by the scanning group in a scanning cycle in the second scanning direction;

[0132] ω1 The first scanning speed in the first scanning direction;

[0133] ω 2 The second scanning speed in the second scanning direction.

[0134] In yet another embodiment, in a scanning period, the angle α scanned by the scanning group of the scanning module in the second scanning direction period is greater than the horizontal detection field of view angle α in the second scanning direction FOV , that is, α period > α FOV , that is, the scanning module in the second direction reserves some angles as a redundancy amount, and the light-emitting module does not emit light within the redundant angles, avoiding the corners of the surface in the scanning device in the second scanning direction that may cause the emitted laser to be uncontrollable, resulting in stray light in the cavity. Therefore, the scanning module in the first direction can quickly rotate instantaneously when the light-emitting module does not emit light to achieve the stepping of the scanning device in this direction. Therefore, the calculation formula for the inter-group interval is still:

[0135]

[0136] where δβ is the inter-group interval;

[0137] α period is the angle scanned by the scanning group in a scanning period in the second scanning direction;

[0138] α FOV is the detection field of view angle in the second scanning direction, and α period > α FOV ;

[0139] ω 1 is the first scanning speed in the first scanning direction;

[0140] ω 2 is the second scanning speed in the second scanning direction.

[0141] The inter-group intervals in the above embodiments are all obtained by adjusting the scanning step amount of the scanning device in the first scanning direction in the scanning module, and the scanning period is realized by the scanning detection field of view angle and scanning speed of the scanning device in the second scanning direction, which is beneficial to setting the lidar detection point cloud in a more reasonable form and facilitating the processing of lidar data.

[0142] In another embodiment, when the scanning module enters another preset sub-region from one preset sub-region for scanning and the scanning density changes greatly between the two preset sub-regions, the variation time of the step size can be increased by increasing the redundant angle of the scanning device in the second scanning direction. For example, if the scanning device in the second direction is a multi-faceted rotating mirror, the variation time of the inter-group interval can be increased by increasing the empty scanning surface of the multi-faceted rotating mirror, so that the scanning speed change of the scanning module is as uniform as possible, reducing the motion vibration caused by the speed change of the scanning device in the first direction and maintaining the stability of the scanning motion of the scanning device in the first direction. Therefore, the calculation formula for the inter-group interval is still:

[0143]

[0144] where δβ is the inter-group interval;

[0145] α period is the scanning angle of a scanning group in one scanning period in the second scanning direction;

[0146] α FOV is the detection field of view angle in the second scanning direction;

[0147] α is the field of view angle corresponding to each face of the multi-faceted rotating mirror;

[0148] k is the number of faces of the multi-faceted rotating mirror;

[0149] ω 1 is the first scanning speed in the first scanning direction;

[0150] ω 2 is the second scanning speed in the second scanning direction.

[0151] It can be understood that in another scanning mode of the lidar, the scanning module can also scan in the following manner.

[0152] Among them, the multi-faceted rotating mirror can be a regular rotating mirror or an irregular rotating mirror. A regular rotating mirror is a rotating mirror with equal central angles corresponding to each face, and an irregular rotating mirror is a rotating mirror with at least one face having a central angle different from that of the other faces.

[0153] It can be understood that by setting the empty scanning surface and the size of the central angle corresponding to the scanning surface of the scanning device in the second direction, the scanning speed change of the scanning device in the first direction can be made as uniform as possible, ensuring the stability of the motion of the scanning device in the first dimension.

[0154] Such as Figure 7-1As shown in the figure, a sectional view of an irregular hexahedron mirror is shown, where surface A and surface D are the first scanning surfaces, and the included angles corresponding to the center of the rotating mirror are the same. Surfaces B, C, D, and E are the second scanning surfaces, and the included angles corresponding to the center of the rotating mirror are the same. Considering the width of the light beam, a redundant angle of 10 degrees is set, with 5 degrees on each side.

[0155] As Figure 7-2 shown, where surface A corresponds to the largest detection field of view, that is, the total detection field of view, and the field of view angle is 120 degrees. Therefore, it can be determined that the included angle of surface A corresponding to the center of the rotating mirror is 120 / 2 + 10 = 70 degrees, and 60 degrees of it is used for scanning here. Similarly, the included angle of surface D corresponding to the center of the rotating mirror is 70 degrees. The field of view angle of surface F corresponds to the detection field of view angle of one of the preset sub-regions. It can be seen that the field of view angle corresponding to surface F is 90 degrees, and the included angle of surface F corresponding to the center of the rotating mirror is 55 degrees. Similarly, the included angles of surfaces B, C, E, and F corresponding to the center of the rotating mirror are all 55 degrees. It can be understood that the irregular rotating mirror is symmetrically arranged along the middle axis to ensure the stability of the scanning rotation.

[0156] As Figure 7-3 shown, a sectional view of a regular tetrahedron mirror is shown in the figure, where surfaces A, B, C, and D have the same included angle corresponding to the center of the rotating mirror, which is 90 degrees. Considering the width of the light beam, a redundant angle of 20 degrees is set, with 10 degrees on each side. Therefore, the total achieved detection field of view angle is 140 degrees, as Figure 7-4 shown.

[0157] Among them, the redundant angle corresponding to the scanning surface is related to the size of the light spot and the proportion of the light spot occupying the entire scanning surface. It can be understood that the larger the light spot, the larger the set redundant angle; the larger the proportion of the light spot occupying the entire scanning surface, the larger the redundant angle that needs to be set. It can be understood that by reasonably setting the redundant angle, the interference of stray light in the cavity can be better reduced.

[0158] In one embodiment, as Figure 8 shown, the scanning module accesses the detection laser and emits the detection laser to a preset area. The scanning module scans the preset area using a preset scanning mode corresponding to the preset area, including:

[0159] S221, if the detection laser enters the first field of view angle corresponding to the first preset area, the emission module outputs the detection laser twice in succession with a first preset delay time.

[0160] Set the first field of view angle to the angle value within the first detection field of view angle range corresponding to the first preset area. If the detection laser enters within the first field of view angle, that is, it enters the first preset area of the region of interest in the preset area, the emission module outputs the detection laser for two adjacent times with a first preset delay time. In this way, the lidar outputs the detection laser for two adjacent times with different preset delay times in a new scene, changing the scanning resolution and enhancing the flexibility of the scanning resolution of the lidar.

[0161] In one embodiment, when the scanning module scans the first preset area, the emission module changes from the original preset delay time T 0 to output the detection laser for two adjacent times with the first preset delay time T 1 . Among them, the original preset delay time T 0 is greater than the first preset delay time T 1 ; or the original preset delay time T 0 is equal to the first preset delay time T 1 . If the first preset delay time T 1 is less than the original preset delay time T 0 , then the detection laser scan lines corresponding to the first preset area are denser than before, improving the scanning resolution for the first preset area and enhancing the detection ability of the lidar. If the first preset delay time T 1 is equal to the original preset delay time T 0 , then the scanning resolution of the lidar remains unchanged. It should be noted that the specific value of the first preset delay time T 1 in this embodiment is not limited and can be set according to the scanning resolution required in actual applications.

[0162] S222. The scanning module accesses the detection laser and emits the detection laser to the first preset area.

[0163] S223. If the first field of view angle meets the first preset condition, the scanning module scans the first preset area in the first preset scanning mode, where the preset scanning mode includes the first preset scanning mode and the preset condition includes the first preset condition.

[0164] In one embodiment, the first preset condition is that the first field of view angle is less than or equal to the detection field of view angle. Since the region of interest is generally less than or equal to the preset area, the first field of view angle corresponding to the first preset area is also less than or equal to the detection field of view angle. How to obtain the specific first preset area and the first field of view angle is not limited in this embodiment and is set according to the scanning requirements of the lidar.

[0165] In one embodiment, the angular range of the first field of view angle is the angular range of the detection field of view angle at a preset ratio. In a specific embodiment, the preset ratio is less than or equal to 50%. For example, when the preset ratio is 50%, if the angular range of the horizontal detection field of view angle of the detection field of view angle is -60° to 60°, the angular range of the horizontal detection field of view angle of the first field of view angle is -30° to 30°. Another example is that when the preset ratio is 36%, if the angular range of the vertical detection field of view angle of the detection field of view angle is -12.5° to 12.5°, the angular range of the vertical detection field of view angle of the first field of view angle is -4.5° to 4.5°. In this embodiment, the preset ratio is not specifically limited. For example, it can also be 30%, 45%, 60%, 75%, etc. The specific parameter settings are determined according to the scanning resolution ability of the scanning module for the first preset area.

[0166] In one embodiment, the first preset scanning mode is that the scanning group scans the first preset area with a first preset step size, where the scanning group is N scanning lines formed by the detection laser emitted by the emission module at one time, and N is an integer.

[0167] In a specific embodiment, as Figure 5 shown, the first preset step size is where n1 is a positive integer that cannot be divided evenly by N and n1 < N, and δθ is the scanning interval angle between each scanning line in the scanning group. The scanning module uses the first preset scanning mode with the first preset step size of to scan the first preset area to obtain the echo laser of the first preset area. Compared with the fixed scanning mode, since the step size changes according to the scanning density n1, the receiving module can obtain echo laser information that matches the scanning requirements of the first preset area. After processing the echo laser information, point cloud information such as distance information, speed information, azimuth information, shape information, and reflectivity information that matches the requirements of the first preset area is obtained.

[0168] In a specific embodiment, the first preset delay time T 1 is equal to the time required for the scanning group to complete the first preset step size. In this way, if the detection laser enters the first field of view angle corresponding to the first preset area, the emission module outputs the detection laser twice at adjacent times with the first preset delay time T 1 Since the first preset step size Less than the fixed step size N×δθ. Since the step size of the first preset sub-region is greater than that of the second preset sub-region, if the step time, i.e., the preset delay time, is the same, then the step speed of the first preset sub-region is greater than that of the second preset sub-region. The step speed of the first scanning component will change significantly, which will cause the scanning module to vibrate greatly and affect the lifespan of the device. Therefore, by controlling the step time of the large step size region, the step speed of the large step size region can be effectively controlled, the scanning stability of the scanning module can be improved, and the lifespan of the scanning module can be extended.

[0169] As Figure 5 shown, in a specific embodiment, the region 62 with dense scanning lines is the first preset region of the region of interest. In the figure, the same line type represents N detection laser scanning lines output by the emission module of the lidar at one time to form a scanning group. Four line types indicate that the emission module sequentially outputs four groups of detection laser scanning groups A, B, C, and D for vertical scanning. The number of scanning lines in each scanning group is N, and the interval angle between adjacent scanning lines is δθ. At time t1, the A scanning group outputs N detection laser scanning lines of group A from top to bottom at a fixed frequency, and the scanning module continues to scan downward with a first preset step size; when the scanning module reaches the moment t2 after completing the first preset step size, the B scanning group outputs N detection laser scanning lines of group B from top to bottom and continues to scan; when the scanning module reaches the moment t3 after completing the first preset step size, the C scanning group outputs N detection laser scanning lines of group C from top to bottom and continues to scan until the scanning of the entire space region is completed. The overlapping region of the intermediate scanning lines forms a resolution, realizing the key scanning of the first preset region of the region of interest by the scanning module in the lidar. The delay time between the time t1 when the scanning module starts and the moment t2 when it completes the first preset step size, or the delay time between the time t2 when the scanning module starts and the moment t3 when it completes the first preset step size, is the first preset delay time T 1 .

[0170] In a specific embodiment, the detection laser output by the emission module each time forms a scanning group. When the number of scanning lines in each scanning group is 4, the interval angle δθ between adjacent scanning lines is 0.1°. Let a positive integer n1 that cannot be divided evenly by N be 3, then the first preset step size of each scanning group is about 0.133°. Then, in the first preset region of the region of interest with dense scanning lines, a resolution of 0.1° / 3 = 0.033° can be achieved, and the time required for the laser scanning line to complete the first preset step size of 0.133° is the first preset delay time T1 Since the first preset delay time T 1 The corresponding first preset step size is 0.133°. Compared with the fixed delay time larger than the first preset delay time T 1 For the large fixed delay time, the lidar outputs denser scan lines to the first preset area of the area of interest in the first preset scan mode. Therefore, denser echo laser information of the scanned area of interest is obtained. After processing the information carried by the echo laser, point cloud information with more distance information, speed information, azimuth information, shape information, and reflectivity information of the first preset area of the area of interest is obtained, thereby improving the scanning resolution of the lidar.

[0171] It should be noted that in this embodiment, the specific values of the number of scan lines N in each scan group, the interval angle δθ between each scan line, and the positive integer n1 are not limited and can be set according to the scanning resolution required in actual applications.

[0172] In this embodiment, the position information of the first preset area of the area of interest and the position information of the preset area are not limited. For example, the position information of the first preset area of the area of interest may include the coordinates of the boundary points of the area of interest, and the position information of the preset area scanned by the laser may include the coordinates of the boundary points of the preset area scanned by the laser.

[0173] In the above embodiment, when the detection laser enters the first preset area of the area of interest, the emission module outputs the detection laser twice at adjacent times with the first preset delay time T 1 While the scanning module scans the first preset area in the first preset scan mode with the first preset step size, it can indeed improve the scanning resolution of the first preset area and enhance the detection ability of the first preset area. However, there is a technical problem that it is difficult to further improve the scanning resolution of the lidar for more important areas within the first preset area.

[0174] In another embodiment, as Figure 9 shown, the scanning module accesses the detection laser and emits the detection laser to the preset area. The scanning module scans the preset area in the preset scan mode corresponding to the preset area, and further includes:

[0175] S231, if the detection laser enters the second field of view angle corresponding to the second preset area, the emission module outputs the detection laser twice at adjacent times with the second preset delay time, where the second preset delay time is less than the first preset delay time.

[0176] S232, the scanning module accesses the detection laser and emits the detection laser to the second preset area.

[0177] S233, if the second field of view angle meets the second preset condition, the scanning module scans the second preset area in the second preset scanning mode, where the preset scanning mode includes the second preset scanning mode and the preset condition includes the second preset condition.

[0178] In one embodiment, the second preset condition is that the second field of view angle is less than the first field of view angle, and the second preset scanning mode is that the scanning group sequentially scans the second preset area with a second preset step size, where the scanning group is N scanning lines formed by the detection laser emitted by the emission module at one time, N is an integer, and the second preset step size is where n2 is an integer that cannot be divided evenly by N and n1 < n2 < N, and δθ is the scanning interval angle between each pair of scanning lines.

[0179] In a specific embodiment, as Figure 3 shown, the area denser than the scanning line dense area 62 is the second preset area (not shown in the figure), and the second preset step size is where n2 is a positive integer that cannot be divided evenly by N and n1 < n2 < N, and δθ is the scanning interval angle between each pair of scanning lines in the scanning group. The scanning module uses the second preset scanning mode with the second preset step size of to scan the second preset area to obtain the echo laser of the second preset area. Compared with the first preset scanning mode, since the second preset step size is less than the first step size therefore, the scanning module emits a larger number of detection lasers than the first scanning mode to scan the second preset area, and can obtain denser echo laser information of the second preset area. After processing the echo laser information, more point cloud information of distance information, speed information, azimuth information, shape information, and reflectivity information of the second preset area is obtained.

[0180] In a specific embodiment, the second preset delay time T 2 is equal to the time required for the scanning group to complete the second preset step size. In this way, if the detection laser enters the second field of view angle corresponding to the second preset area, the emission module outputs adjacent detection lasers with the second preset delay time T 2 Since the second preset step size is less than the first step size therefore, the second preset delay time T 2 is less than the first preset delay time T 1 When the emission module outputs adjacent detection lasers with the second preset delay time T 2 in this way, the lidar outputs adjacent detection lasers with a smaller delay time when scanning the second preset area, thereby improving the scanning resolution of the lidar and enhancing the detection ability of the lidar.

[0181] In addition, when lidar uses the direct detection principle to detect the laser reflected by an object, due to the overlap of the preset areas of laser scanning, the situation where the preset area of laser scanning and the receiving detection module cannot correspond occurs, resulting in signal crosstalk of the echo laser. The information carried by the crosstalk echo laser will become false point cloud information after being processed, forming false targets.

[0182] To adapt to various application scenarios, in this embodiment, the preset step size needs to be smaller than the crosstalk range angle of each application scenario. In this way, when optical signal crosstalk of the echo laser reflected by a high-speed moving target at a short distance occurs, the phenomenon of crosstalk occurring once only affects the scanning range of the same group of scan lines, reducing the impact of the crosstalk problem on the lidar, thereby avoiding the situation of false targets occurring multiple times, improving the resolution ability of the lidar in the spatial area, and preventing traffic safety accidents caused by misjudgment.

[0183] In one embodiment, the crosstalk range angle of each application scenario is set to be less than or equal to 2°, that is, the interval angle δθ of the scan lines is set to δθ≦0.2°, which can improve the crosstalk resistance ability of the lidar and further improve the detection ability of the lidar.

[0184] In a specific embodiment, the interval angle of each scan line is set to 0.2°. The scan line combination scheme of the lidar includes: the scan lines are 128 lines, 8 scan groups are set, and the 8 groups of scan lines form a 1.6° spatial area. Each group performs 16 scans, that is, when a single detection laser output by each emission module completes a complete horizontal field of view or vertical field of view scanning cycle, a frame of point cloud image is formed. The spatial area corresponding to this frame of point cloud image is 1.6°, that is, within the 1.6° spatial area, the detection laser output by the emission module of the lidar once forms 16 detection laser scan lines.

[0185] In another specific embodiment, the interval angle of each scan line is set to 0.1°. The scan line combination scheme of the lidar includes: the scan lines are 256 lines, 16 scan groups are set, and the 16 groups of scan lines form a 1.6° spatial area. Each group performs 16 scans, that is, when a single detection laser output by each emission module completes a complete horizontal field of view or vertical field of view scanning cycle, a frame of point cloud image is formed. The spatial area corresponding to this frame of point cloud image is 1.6°, and within the 1.6° spatial area, the detection laser output by the emission module of the lidar once forms 16 detection laser scan lines.

[0186] In yet another specific embodiment, the interval angle between each scanning line is set to 0.1°. The scanning line combination scheme of the lidar includes: there are 260 scanning lines, 20 scanning groups are set, and the 20 scanning lines form a 2.0° spatial region. Each group performs 13 scans. That is, when a single detection laser output by each emission module completes a full horizontal field of view or vertical field of view scanning cycle, a frame of point cloud image is formed. The spatial region corresponding to this frame of point cloud image is 1.6°. Within the 1.6° spatial region, the detection laser output by the emission module of the lidar once forms 13 detection laser scanning lines.

[0187] It can be understood that in this application, only the time interval between two adjacent emissions of the same emission group is set, and no specific restrictions are imposed on the time interval between two non-adjacent emissions of the same group. There are also no specific restrictions on the total number of scanning lines, no specific restrictions on the interval angle between each scanning line, and no specific restrictions on the range of the spatial region of each frame of cloud image. In specific implementations, corresponding settings are made according to the detection requirements of the lidar.

[0188] In a specific embodiment, when the number of scanning lines N in each scanning group is 4 and the angular interval angle δθ between each scanning line is 0.1°, the fixed step amount for each scan of the scanning group is 4×0.1°, approximately 0.4°. Then, a resolution of 0.1° can also be achieved in other preset regions where the scanning lines are sparse. The scanning module scans other preset regions outside the region of interest in a fixed scanning mode to obtain the echo laser of other preset regions, and obtains relatively sparse echo laser of other preset regions. After processing the information carried by the echo laser, less point cloud information such as distance information, velocity information, azimuth information, shape information, and reflectivity information of other preset regions can be obtained. In this way, when scanning other preset regions outside the region of interest, the power of the lidar can be reduced, and the amount of data processed by the lidar can be reduced, thereby saving the energy consumed by the lidar.

[0189] S300, the receiving detection module receives the echo laser and converts it into an electrical signal.

[0190] Specifically, the receiving detection module receives the reflected echo laser and converts the echo laser signal into an electrical signal that is convenient for processing.

[0191] S400, the signal acquisition and processing module acquires the electrical signal and processes the electrical signal to obtain the detection information of the preset region.

[0192] Specifically, the signal acquisition and processing module acquires the electrical signal output by the receiving detection module and processes the electrical signal to obtain at least one of the distance information, velocity information, azimuth information, shape information, and reflectivity information of the preset region, and synthesizes it into point cloud information, thereby improving the detection ability of the lidar in various application scenarios.

[0193] The beneficial effects of this embodiment compared with the prior art are as follows:

[0194] This embodiment provides a detection method for a lidar. The emission module outputs adjacent detection lasers with a preset delay time. The preset area is set as the area corresponding to the detection field of view of the lidar. The preset area is scanned using a preset scanning mode corresponding to the preset area. The scanning module also receives the echo laser reflected from the preset area and outputs the echo laser. The receiving and detecting module receives the echo laser and converts it into an electrical signal. The signal acquisition and processing module acquires the electrical signal and processes the electrical signal to obtain the detection information of the preset area, so as to obtain a high-density scanned point cloud of the preset area, obtain more point cloud detection information, thereby improving the scanning resolution ability of the lidar for each preset area, enhancing the scanning flexibility of the lidar for different preset areas, and further enhancing the detection ability of the lidar in different application scenarios.

[0195] In another scanning mode, since the preset delay time is less than the fixed delay time and the preset scanning mode has a higher resolution than the fixed scanning mode, a higher-density scanned point cloud of the preset area can be obtained, thereby obtaining more point cloud detection information, improving the scanning resolution ability of the lidar for the preset area, enhancing the scanning flexibility of the lidar for different preset areas, and further enhancing the detection ability of the lidar in different application scenarios.

[0196] As Figure 10 shown, the second aspect of the embodiment of the present application also provides a detection device for a lidar, including:

[0197] The emission module 1 is used for the emission module to output adjacent detection lasers with a preset delay time;

[0198] The emission optical path module 2 is used for accessing the detection laser and outputting the detection laser;

[0199] The scanning module 3 is used for accessing the detection laser, emitting the detection laser to the preset area, scanning the preset area using a preset scanning mode corresponding to the preset area, and the scanning module is also used for receiving the echo laser reflected from the preset area and outputting the echo laser;

[0200] The receiving and detecting module 4 is used for receiving the echo laser and converting it into an electrical signal;

[0201] The signal acquisition and processing module 5 is used for acquiring the electrical signal and processing the electrical signal to obtain the detection information of the preset area.

[0202] It should be noted that the embodiments of the present application do not limit other components that the lidar further includes, nor do they limit the names of each component in the lidar. It should be noted that the embodiments of the present application do not limit the application scenarios of the lidar. For example, the lidar can be applied in the fields of intelligent transportation, autonomous driving, assisted driving, navigation, mapping, meteorology, aerospace, robotics, etc., for realizing spatial scanning, obstacle avoidance, route planning, meteorological prediction, etc.

[0203] In one embodiment, the emission group in the emission module is a light source. Since improving the output signal-to-noise ratio of the lidar can increase the ranging range of the lidar, different from the existing lidar that improves the ranging range by increasing the emission power of the lidar and improves the resolution by increasing the number of scan line channels. In this embodiment, based on the output signal-to-noise ratio formula of the lidar, while keeping the emission power of the lidar unchanged, keeping the number of scan line channels unchanged (i.e., keeping the channel coefficient unchanged), and keeping the area of the receiving mirror unchanged, the output signal-to-noise ratio of the lidar is improved by reducing the light source interval of the light source in the horizontal and vertical directions, reducing the divergence angle of the detection laser in the horizontal and vertical directions, reducing the angular power of the light source, and increasing the power density of the light source, thereby increasing the ranging range of the lidar and improving the ranging ability of the lidar. At the same time, the overall power consumption of the lidar is also reduced, which is beneficial to environmental protection and energy conservation, and also reduces the requirement for heat dissipation, improving the reliability of the entire lidar.

[0204] The output signal-to-noise ratio formula of the lidar is:

[0205]

[0206] Wherein, SNR is the output signal-to-noise ratio of the lidar;

[0207] P t is the emission power of the lidar;

[0208] S mirrpr is the area of the receiving mirror;

[0209] P θ is the angular power of the light source;

[0210] δθ x is the light source interval in the horizontal direction x;

[0211] δθ y is the light source interval in the vertical direction y.

[0212] θ divx is the divergence angle of the detection laser in the horizontal direction x;

[0213] θ divy is the divergence angle of the detection laser in the vertical direction y;

[0214] P density is the power density of the light source;

[0215] C channel is the channel ratio coefficient between the multi-channel light spot and the single-channel light spot. The more channels there are, the larger the C channel coefficient.

[0216] Among them, based on the divergence angle calculation formula, the divergence angle of the detection laser in the horizontal and vertical directions can be reduced by reducing the light-emitting area of the light source and increasing the equivalent focal length of the emission optical path module of the lidar; based on the calculation formula of the scan line channel interval (also known as the scan line interval), the scan line interval can be reduced by increasing the equivalent focal length of the emission optical path module of the lidar and reducing the light source interval between the light sources.

[0217] The divergence angle calculation formula is:

[0218]

[0219] where θ div is the divergence angle of the detection laser in the horizontal or vertical direction;

[0220] f is the equivalent focal length of the emission optical path module of the lidar;

[0221] L is the length or width of the light-emitting light source of the light source.

[0222] The scan line interval calculation formula is:

[0223]

[0224] where α is the scan line interval;

[0225] f is the equivalent focal length of the emission optical path module of the lidar;

[0226] δθ is the light source interval of each light source in the horizontal or vertical direction.

[0227] In this embodiment, the horizontal direction is the left-right direction relative to the target object in the spatial region, and the vertical direction is the up-down direction relative to the target object in the spatial region.

[0228] In one embodiment, the transmitting module 1 includes at least two light sources and a driving module for driving each light source to output detection laser with a preset delay time. When the lidar detects a target area, the driving module is used to drive multiple light sources in the transmitting module 1 to output detection laser with a preset delay time. Optionally, the length or width L of the emitting light source is less than or equal to 0.2 mm. Further, the length or width L of the emitting light source is less than or equal to 0.1 mm. The preset light source interval δθ of each light source in the horizontal or vertical direction is less than or equal to 0.4 mm. Further, the preset light source interval δθ of each light source in the horizontal or vertical direction is less than or equal to 0.1 mm.

[0229] In one embodiment, at least two light sources in the transmitting module 1 are distributed on a straight line at a preset light source interval. The plane where the light source straight line is located is perpendicular to the normal line of the light emitting direction of the light source. The direction of the straight line is the vertical direction, that is, the up and down direction relative to the target object in the spatial area. Setting the light sources in the vertical direction is beneficial to accelerating the scanning speed of the lidar in the horizontal scanning direction and expanding the scanning field of view in the vertical direction.

[0230] In one embodiment, the light source is a power laser device, and the power laser device is at least one of an edge emitting laser (EEL) or a vertical-cavity surface-emitting laser (VCSEL). The output power of the high-power laser device is greater than or equal to 1000 W / mm 2 . By increasing the output power of the laser device, when the preset ranging range is satisfied, the length or width of the emitting light source can be reduced, thereby reducing the light emitting area of the light source, and further reducing the divergence angle of the detection laser.

[0231] In one embodiment, the power laser device can also form an array laser light source, which can further reduce the light source interval between each light source, further reduce the channel interval of the scanning lines, and improve the resolution of the lidar laser.

[0232] In one embodiment, as Figure 11 shown, the transmitting lens 2 includes a coaxial first lens 21, a second lens 22, and a third lens 23.

[0233] Among them, the first lens 21 receives the detection laser and converts the detection laser in the horizontal light emitting direction into parallel light.

[0234] The second lens 22 receives the parallel light and transmits the parallel light to the third lens 23. The second lens 22 also refracts the detection laser in the vertical light emitting direction to the third lens 23.

[0235] The third lens 23 receives parallel light and transmits it to the scanning module 3. The third lens 23 also converts the detection laser in the direction perpendicular to the emission direction in the detection laser into collimated laser and transmits it to the scanning module 3.

[0236] It should be noted that through the focal length design formed by the second lens and the third lens, the divergence angle of the emitted laser can be effectively reduced, so that the divergence angle θ of the detection laser in the horizontal direction or the vertical direction div and the scanning line interval α can be of the same order of magnitude, which can meet the requirement that the divergence angle θ of the detection laser div is 0.1°, and can also meet the requirement that the scanning line interval α is 0.1°.

[0237] In one embodiment, as Figure 12 shown, a radar system includes a transmitting channel and a receiving channel. A first mirror 31 and a mirror 32 with a through hole are arranged on the transmitting channel. A mirror 32 with a through hole and a second transmitting mirror 35 are arranged on the receiving channel. The scanning module includes a one-dimensional galvanometer 33 in the first scanning direction and a rotating mirror 34 in the second scanning direction.

[0238] The emitted laser is reflected by the first mirror 31 and passes through the mirror 32 with a through hole, and is incident on the one-dimensional galvanometer 33. The one-dimensional galvanometer 33 deflects the emitted laser to the rotating mirror 34, and the emitted laser is reflected by the rotating mirror 34 to the detection field of view;

[0239] The echo laser is first deflected by the rotating mirror 34 to the one-dimensional galvanometer 33, deflected by the one-dimensional galvanometer 33 to the receiving channel, deflected by the mirror 32 with a through hole to the second mirror 35, and deflected by the second mirror 35 to the receiver so that the receiver receives the echo laser.

[0240] It should be noted that in this radar system, by setting the first mirror 31 and the transmitting mirror 32 with a through hole, the transmitting optical path of the radar system forms a long focal length optical path, thereby reducing the far-field divergence angle of the emitted laser and improving the detection ability. At the same time, by setting the mirror 32 with a through hole and the second mirror, the receiving optical path of the radar system forms a long focal length optical path, thereby reducing the FOV on the receiving side and reducing the noise interference on the receiving side, and further improving the ranging. The scanning module of the lidar in this embodiment can achieve a resolution of less than or equal to 0.1° and less than or equal to 0.04° through a preset scanning mode corresponding to a preset delay time, improving the detection ability of far-field targets and the detection ability of the ground line, and thus obtaining higher-resolution point cloud information in the spatial area and improving the resolution ability of the lidar for different areas.

[0241] In one embodiment, the correspondence between the transmitting device and the receiving device of the lidar is one transmit and multiple receives, that is, 1 laser corresponds to multiple receiving detectors. Under the same resolution requirement, by increasing the number of receiving devices corresponding to one transmitting device, the number of parallel transmitting channels corresponding to one transmission is reduced, the width of the light spot in the vertical direction is reduced, so the area of the through holes on the mirror 32 with through holes is reduced, the receiving aperture is increased, and then the area of the received light spot is increased, which is beneficial to improving the ranging performance. In addition, since the number of transmitting channels is reduced, the complexity of the lidar optical path design is reduced and the cost is reduced. It is also possible to further compress the interval between the laser light sources to reduce the interval between the scanning lines, thereby reducing the crosstalk effect caused by the optical signal. Further, the receiving detection module includes a silicon photomultiplier (SiPM) array. When the number of laser light sources in the vertical direction is set to 4, the silicon photomultiplier array distributed in the vertical direction includes 8 silicon photomultiplier units, realizing a one-transmit-two-receive transceiver mode.

[0242] In the above embodiments, the descriptions of the respective embodiments have their own focuses. For the parts not detailed or recorded in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0243] In the embodiments provided in the present application, it should be understood that the disclosed modules and methods can be implemented in other ways. For example, the module embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0244] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A laser radar detection method, characterized in that: include: The transmitting module outputs two consecutive detection lasers with a preset delay time; The scanning module is connected to the detection laser and emits the detection laser to a preset area. The scanning module scans the preset area using a preset scanning mode corresponding to the preset area. The scanning module also receives the echo laser reflected from the preset area and outputs the echo laser. The preset area includes at least one preset sub-area. The scanning direction of the scanning module includes a first scanning direction and a second scanning direction. The receiving detection module receives the echo laser and converts it into an electrical signal; The signal acquisition and processing module acquires the electrical signal and processes the electrical signal to obtain the detection information of the preset area; The preset scanning mode is to scan the preset sub-area using the scanning speed of the scanning group corresponding to the preset sub-area, and determine the scanning speed corresponding to the preset sub-area based on the preset delay time, the inter-group interval, and the preset delay time and the inter-group interval, wherein the scanning group is N scanning lines formed by the detection laser emitted by the emission module once, N is an integer, and the inter-group interval is the inter-group interval angle between the scanning groups emitted in two adjacent times; The calculation formula for the inter-group interval is: in, is the interval between the groups; An angle scanned by the scanning group in one scanning period of the second scanning direction; is the detection field angle of the second scanning direction, and > ; is a first scanning speed in the first scanning direction; is the second scanning speed in the second scanning direction.

2. The detection method according to claim 1, characterized in that: The first scanning direction and the second scanning direction form a preset angle, and the preset angle is less than or equal to 180 degrees; The scanning module scans the preset area using a preset scanning mode corresponding to the preset area, and further includes: The scanning module scans the preset area in the first scanning direction using the preset scanning mode corresponding to the preset area; or The scanning module scans the preset area in the second scanning direction by using the preset scanning mode corresponding to the preset area.

3. The detection method according to claim 2, characterized in that: Before the transmitting module outputs two adjacent detection lasers with a preset delay time, the detection method includes: The laser radar obtains a scanning area corresponding to the detection field of view angle of the scanning module; The laser radar obtains the preset sub-area where the scanning area is located; The laser radar obtains a scanning density corresponding to the preset sub-area; The laser radar controls the transmitting module based on the scanning density to output the detection laser at a preset delay time corresponding to the scanning density.

4. The detection method according to claim 3, characterized in that: The scanning module scans the preset area using a preset scanning mode corresponding to the preset area, including: The scanning module obtains a preset scanning mode corresponding to the scanning density; The scanning module scans the preset sub-area using the preset scanning mode.

5. The detection method according to claim 4, characterized in that: The preset scanning mode is also to scan the preset sub-area using the inter-group interval of the scanning group corresponding to the preset sub-area, the scanning group is N scanning lines formed by the detection laser emitted by the emission module once, and the inter-group interval is the inter-group interval angle between the scanning groups emitted in two adjacent times; The calculation formula of the inter-group interval is also: in, is the interval between the groups; is the spacing angle between the scan lines in the scan group; N is the number of scan lines of each scan group, and N is an integer; n is a multiple of the scan line encryption corresponding to the preset sub-area, n is a real number and n≥0.

6. The detection method according to claim 1, characterized in that: The transmitting module includes at least one transmitting group; The transmitting module outputs two consecutive detection lasers with a preset delay time, including: The same transmitting group of the transmitting module outputs two consecutive detection lasers with the preset delay time; or Each of the emission groups of the emission module outputs two adjacent detection lasers with the preset delay time.

7. A laser radar detection device, characterized in that: include: A transmitting module, used for the transmitting module to output two adjacent detection lasers with a preset delay time; An emission optical path module, used for receiving the detection laser and outputting the detection laser; A scanning module, used for receiving the detection laser and emitting the detection laser to a preset area, wherein the scanning module scans the preset area using a preset scanning mode corresponding to the preset area, and further receives an echo laser reflected from the preset area and outputs the echo laser; the preset area includes at least one preset sub-area; and the scanning direction of the scanning module includes a first scanning direction and a second scanning direction; A receiving detection module, used for receiving the echo laser and converting it into an electrical signal; A signal acquisition and processing module, used to acquire the electrical signal and process the electrical signal to obtain detection information of the preset area; The preset scanning mode is to scan the preset sub-area using the scanning speed of the scanning group corresponding to the preset sub-area, and determine the scanning speed corresponding to the preset sub-area based on the preset delay time, the inter-group interval, and the preset delay time and the inter-group interval, wherein the scanning group is N scanning lines formed by the detection laser emitted by the emission module once, N is an integer, and the inter-group interval is the inter-group interval angle between the scanning groups emitted in two adjacent times; The calculation formula for the inter-group interval is: in, is the interval between the groups; An angle scanned by the scanning group in one scanning period of the second scanning direction; is the detection field angle of the second scanning direction, and > ; is a first scanning speed in the first scanning direction; is the second scanning speed in the second scanning direction.

8. The detection device according to claim 7, characterized in that The emission optical path module includes a coaxial first lens, a second lens and a third lens; The first lens is connected to the detection laser output by the transmitting module, and converts the detection laser in the horizontal emitting direction of the detection laser into parallel light; The second lens receives the parallel light and transmits the parallel light to the third lens, and the second lens further refracts the detection laser light in the vertical light-emitting direction of the detection laser light to the third lens; The third lens receives the parallel light and transmits it to the scanning module. The third lens also converts the detection laser in the vertical light emission direction into collimated laser and transmits it to the scanning module. Wherein, the second lens and the third lens form a telephoto optical path; The equivalent focal length of the telephoto optical path is greater than or equal to 50 mm.

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