Control Method of LiDAR and LiDAR

Abstract

The present invention provides a control method for a lidar, wherein the lidar includes a laser array having N lasers, and the control method includes: S101: controlling n lasers to emit first detection laser beams, and controlling k lasers among them to emit second detection laser beams; where n ≤ N, the k lasers are selected from the n lasers, k < n, and the optical intensity of the first detection laser beam is greater than that of the second detection laser beam; S102: receiving the echoes reflected by the first detection laser beam and the second detection laser beam on the target; S103: calculating the distance of the target according to the echoes; and S104: when a target is detected within a preset distance, reducing the emission optical intensity of at least some of the n lasers emitting the first detection laser beam within the range corresponding to the target in the next detection period.

Description

Technical Field

[0001] The present disclosure relates to the field of optoelectronic detection technologies, and in particular, to a control method and a lidar for reducing the emission light intensity of a lidar without weakening the short-distance detection ability. Background Art

[0002] Lidar is a general term for laser active detection sensor devices, and its working principle is roughly as follows: The transmitter of the lidar emits a laser beam. After the laser beam encounters an object, it is diffusely reflected and returns to the laser receiver. The radar module multiplies the time interval between the transmitted and received signals by the speed of light and then divides by 2 to calculate the distance between the transmitter and the object. According to the number of laser beams, there are usually, for example, single-line lidars, 4-line lidars, 8 / 16 / 32 / 64-line lidars, etc. The higher the number of beams, the more complex the structure of the lidar and the higher the integration level. For a lidar with a high integration level, it is necessary to minimize the power consumption as much as possible.

[0003] In many actual installation and use processes, there may be some deliberately set obstacles very close to the lidar, such as some beams being blocked by the vehicle body at certain horizontal angles; for another example, only a part of the detection range of the horizontal angles of the lidar is used, and other angles are blocked. At the same time, in the use environment of the lidar, there are often some targets very close to the lidar (such as ≤ 3 m). The detection of these short-distance targets can be achieved without too high detection light intensity, thus power consumption can be saved. In some lidar solutions, according to the detection results of the lidar, if an object is detected nearby, the emission light intensity is reduced when the same angular range is scanned next time, only meeting the light intensity requirements for near measurement, thereby reducing power consumption. However, although this strategy reduces the emission light intensity, it may result in the situation that nearby objects cannot be detected.

[0004] Reference Figure 1A As shown, the emission light intensity is very high during the first detection, and an object is detected nearby; reference Figure 1B As shown, when scanning the angular range of the nearby object for the second time, the emission light intensity is reduced, but the echo intensity after reflection from the nearby object may not reach the threshold Th, resulting in the nearby object not being detected during the second scan. Therefore, although the power consumption is reduced, the short-distance detection ability is weakened or even lost.

[0005] Figure 1C explains the reason why a lidar with non-coaxial transceiver weakens or even loses the short-distance detection ability while reducing power consumption. In a lidar, a laser and a detector set for matching the far-field view form a channel, as Figure 1CAs shown, for channels A and B of the lidar, when the lidar is used to detect distant objects, after the detection laser beam L0 emitted by the laser in channel A is reflected by the distant target object OB1, the lidar echo is close to parallel light and will irradiate the detector D1 in channel A, as Figure 1C shown in the upper left of Figure 1C which is an ideal situation. When the lidar is used to detect nearby objects OB2, after the detection laser beam L0 emitted by the laser in channel A is reflected by the nearby target object, the lidar echo cannot be approximated as parallel light, and spot offset and dispersion occur when it reaches the focal plane where the detector is located, and it will irradiate the detector D2 in channel B next to the detector in channel A, as shown in the lower left of

[0006]

[0007] The content in the background technology section is only the technology known to the applicant and does not necessarily represent the prior art in this field. Summary of the Invention

[0008] The present invention provides a control method and a lidar for reducing the light intensity of the lidar emission without weakening the near-distance detection ability.

[0009] The present invention provides a control method for a lidar, wherein the lidar includes a laser array having N lasers, and the control method includes:

[0010] S301: Control n lasers to emit a first detection laser beam, and control k lasers among them to emit a second detection laser beam; where n ≤ N, the k lasers are selected from the n lasers, k < n, and the light intensity of the first detection laser beam is greater than the light intensity of the second detection laser beam;

[0011] S302: Receive the echoes reflected by the first detection laser beam and the second detection laser beam on the target object;

[0012] S303: Calculate the distance of the target object according to the echo; and

[0013] S304: When a target is detected within a preset distance, in the next detection cycle, reduce the luminous intensity of at least some of the n lasers that emit the first detection laser beam within the range corresponding to the target.

[0014] According to one aspect of the present invention, the step S304 includes: obtaining the angular range of the target within the preset distance according to the distance of the target, and reducing the luminous intensity of the lasers within the angular range among the n lasers that emit the first detection laser beam in the next detection cycle.

[0015] According to one aspect of the present invention, the step S304 includes: obtaining the angular range of the target within the preset distance according to the distance of the target, and turning off some of the lasers within the angular range among the n lasers in the next detection cycle.

[0016] According to one aspect of the present invention, p lasers and one detector form a detection channel, p≥1, and the step S304 includes: when a target within a preset distance is detected by one of the detection channels, controlling the lasers of the detection channels within a preset range around the detection channel to reduce the luminous intensity of the lasers that emit the first detection laser beam in the next detection cycle.

[0017] According to one aspect of the present invention, the preset range is divided according to the midline between two near measurement point clouds.

[0018] According to one aspect of the present invention, the step S304 includes: correcting the angular range in the next detection cycle according to one or more of the type of the target, the motion parameters, and the detection parameters of the lidar.

[0019] According to one aspect of the present invention, compared with the second detection laser beam, the first detection laser beam is used to measure a target at a farther distance, and the N lasers are divided into m groups to emit light in sequence, m is an integer and m>1, and the step S301 includes:

[0020] At each horizontal angle position of the lidar, controlling n lasers in each group of laser arrays to emit the first detection laser beam;

[0021] At the same horizontal angle position, controlling the k lasers in the laser array to emit the second detection laser beam before or after emitting the first detection laser beam.

[0022] According to one aspect of the present invention, the first detection laser beam and the second detection laser beam have different pulse codes;

[0023] Step S303 includes: determining whether the echo corresponds to the first detection laser beam or the second detection laser beam according to different pulse codings, and calculating the distance of the target object according to the time point when the first detection laser beam or the second detection laser beam is emitted.

[0024] According to one aspect of the present invention, step S303 includes:

[0025] Judging whether the echo corresponds to the first detection laser beam or the second detection laser beam through the time window for receiving the echo, and calculating the distance of the target object according to the time point when the first detection laser beam or the second detection laser beam is emitted.

[0026] According to one aspect of the present invention, step S303 includes:

[0027] Respectively calculating the possible distances between the target object and the lidar according to the detected echo and the time points when the first detection laser beam and the second detection laser beam are emitted;

[0028] Judging whether the echo signal corresponds to the first detection laser beam or the second detection laser beam, and determining the distance of the target object.

[0029] The present invention also provides a lidar, including:

[0030] A laser array having N lasers, configured to emit detection laser beams;

[0031] A receiving unit, including a detector array, configured to receive the echo reflected by the detection laser beam on the target object and convert it into an electrical signal; and

[0032] A control unit, coupled to the laser array and the receiving unit, configured to calculate the distance of the target object according to the electrical signal, and configured to control n lasers to emit the first detection laser beam, and control k lasers among them to emit the second detection laser beam; where n ≤ N, the k lasers are selected from the n lasers, k < n, and the light intensity of the first detection laser beam is greater than the light intensity of the second detection laser beam; wherein the control unit is configured to: when a target object is detected within a preset distance, reduce the light intensity of at least some of the n lasers emitting the first detection laser beam within the range corresponding to the target object in the next detection cycle.

[0033] According to one aspect of the present invention, the control unit is configured to: obtain the angular range of the target object within the preset distance according to the distance of the target object, and reduce the light intensity of the lasers within the angular range among the n lasers emitting the first detection laser beam in the next detection cycle.

[0034] According to one aspect of the present invention, the control unit is configured to: obtain an angular range of the target objects within a preset distance according to the distance of the target objects, and turn off the emission of the first detection laser beam by some of the n lasers within the angular range in the next detection cycle.

[0035] According to one aspect of the present invention, p lasers and one detector form a detection channel, where p≥1, and the control unit is configured to: when one of the detection channels detects a target object within a preset distance, control the lasers of the detection channels within a preset range around the detection channel to reduce the emission light intensity of the first detection laser beam in the next detection cycle.

[0036] According to one aspect of the present invention, the preset range is divided according to the midline between two near-measurement point clouds.

[0037] According to one aspect of the present invention, the control unit is configured to: obtain an angular range of the target objects within a preset distance according to the distance of the target objects output by the control unit, and reduce the emission light intensity of the lasers within the angular range and within a preset range adjacent to the angular range in the far-measurement mode in the next detection cycle.

[0038] According to one aspect of the present invention, the control unit is configured to: correct the angular range in the next detection cycle according to one or more of the type of the target object, the motion parameters, and the detection parameters of the lidar.

[0039] According to one aspect of the present invention, compared with the second detection laser beam, the first detection laser beam is used to measure target objects at a farther distance. The N lasers are divided into m groups and emit light in sequence, where m is an integer and m>1. The control unit is configured to: at each horizontal angle position of the lidar, control n lasers in each group of laser arrays to emit the first detection laser beam; at the same horizontal angle position, control the k lasers in the laser array to emit the second detection laser beam before or after emitting the first detection laser beam.

[0040] According to one aspect of the present invention, the first detection laser beam and the second detection laser beam have different pulse codings;

[0041] The control unit is configured to: determine whether the echo corresponds to the first detection laser beam or the second detection laser beam according to different pulse codings, and calculate the distance of the target object according to the time point of emitting the first detection laser beam or the second detection laser beam.

[0042] According to one aspect of the present invention, the control unit is configured to: determine whether the echo corresponds to the first detection laser beam or the second detection laser beam by receiving the time window of the echo, and calculate the distance of the target object according to the time point when the first detection laser beam or the second detection laser beam is emitted.

[0043] According to one aspect of the present invention, the control unit is configured to: respectively calculate the possible distances between the target object and the lidar according to the detected echo and the time points when the first detection laser beam and the second detection laser beam are emitted; determine whether the echo signal corresponds to the first detection laser beam or the second detection laser beam, and determine the distance of the target object.

[0044] The present invention also provides a computer-readable storage medium, including computer-executable instructions stored thereon, and the executable instructions implement the control method as described above when executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The schematic embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation to the present disclosure. In the drawings:

[0046] Figure 1A and Figure 1B shows a schematic diagram of the strategy of reducing the emission light intensity when there is an object nearby adopted by the lidar;

[0047] Figure 1C explains the reason for reducing power consumption while weakening or even losing the near-distance detection ability;

[0048] Figure 2 shows a schematic diagram of the emission unit of the lidar according to an embodiment of the present invention;

[0049] Figure 3 shows a schematic diagram of the laser array according to an embodiment of the present invention;

[0050] Figure 4A shows the trajectories of the laser beams scanned on the distant target object by the lidar;

[0051] Figure 4B shows a schematic diagram of the stacking and redundancy of the light spots on the near target object by the lidar;

[0052] Figure 5 shows the logical arrangement (emission timing) of multiple lasers of the laser array according to an embodiment of the present invention;

[0053] Figure 6 shows the emission timings of the first mode and the second mode according to an embodiment of the present invention;

[0054] Figure 7 Shows the emission timing of the first mode and the second mode according to another embodiment of the present invention;

[0055] Figure 8 Shows the logical arrangement (emission timing) of the laser array at adjacent horizontal angular positions according to an embodiment of the present invention;

[0056] Figure 9 Shows a schematic diagram of a lidar according to an embodiment of the present invention;

[0057] Figure 10A Shows a schematic diagram of a method for distance measurement using a lidar according to an embodiment of the present invention;

[0058] Figure 10B Shows a schematic diagram of a method for distance measurement using a lidar according to another embodiment of the present invention;

[0059] Figure 11 Shows a flowchart of a control method for a lidar according to an embodiment of the present invention;

[0060] Figure 12a Shows a schematic diagram of the emission intensity of a lidar according to the second aspect of the present invention;

[0061] Figure 12b Shows the use of Figure 12a A schematic diagram of the lidar point cloud of the scheme;

[0062] Figure 13a And 13b Shows a schematic diagram of the first detection and the second detection of a lidar according to an embodiment of the present invention;

[0063] Figure 14 Shows a working method of a lidar according to an embodiment of the present invention;

[0064] Figure 15 Shows a schematic diagram of the division of the influence domain according to an embodiment of the present invention;

[0065] Figure 16 Shows a detection schematic diagram for reducing the horizontal angular resolution according to an embodiment of the present invention; and

[0066] Figure 17 Shows a detection schematic diagram for reducing the vertical angular resolution according to an embodiment of the present invention. Detailed implementation manners

[0067] In the following text, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present invention. Therefore, the drawings and the description are considered to be exemplary in nature rather than restrictive.

[0068] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0069] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a connection capable of mutual communication; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0070] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath", and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0071] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0072] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0073] The first aspect

[0074] The first aspect of the present invention relates to a laser emission unit, which can be used as a laser emission unit of a lidar, and will be described in detail below with reference to the accompanying drawings.

[0075] As Figure 2 shown, the emission unit 100 includes: a laser array 101 and a control unit 102. The laser array 101 includes a plurality of lasers, which are arranged on one or more substrates, and each laser can be individually driven and controlled to emit light. Figure 2 schematically shows a schematic diagram of a plurality of lasers included in the laser array 101 arranged on a single substrate (such as a circuit board). The laser array 101 includes, for example, four columns of lasers, a total of 30 lasers. It is easy for those skilled in the art to understand that the present invention is not limited thereto. The laser array 101 may include more or fewer lasers, and the physical arrangement of the lasers can be arbitrarily set according to needs. For example, it can also be conceived to arrange a plurality of lasers on a plurality of substrates, as Figure 3 shown. According to an embodiment of the present invention, the emission unit 100 further includes an emission lens (not shown), which is used to modulate (collimate) each laser beam emitted by the laser into a parallel light and emit it into the ambient space around the lidar. Each laser in the laser array 101 is preferably located at different heights on the focal plane of the emission lens, and after passing through the emission lens, it corresponds to different vertical fields of view.

[0076] Figure 3 shows a laser array 101 according to another embodiment of the present invention. The laser array 101 includes a plurality of substrates 1012 and lasers 1011 arranged on each substrate 1012. Each laser 1011 is at a different height on the focal plane of the emission lens, corresponding to different vertical fields of view of the lidar respectively.

[0077] As Figure 2 shown, the control unit 102 is coupled to the laser array 101 and configured to control the lasers in the laser array 101 to emit light. The control unit 102 may include a high-voltage unit and a logic control unit, where the high-voltage unit is used to generate the high voltage required to drive the lasers to emit light, and the logic control unit is used to control the light-emitting timing and logic of the laser array 101. Details are described below.

[0078] In one example, the lidar of the present invention is angle-triggered. At each horizontal angle position of the lidar, the lidar completes a complete ranging process. For example, the horizontal angle resolution of the lidar is 0.2°. Each horizontal angle of the lidar, that is, every 0.2°, starting from 0°, performs an angle trigger at 0°, 0.2°, 0.4°... to complete a complete ranging process. Taking a rotation speed of 10 Hz, a horizontal angle resolution of 0.2°, and a ranging distance of 200 m as an example, the flight time for one ranging is 1.34 us, and the time taken to turn 0.2° is 55.6 us. That is to say, at most 41 times of light emission and reception are allowed within this time (55.6 / 1.34 = 41.5). For mid- and high-line-number lidars, such as 64-line and 128-line lidars, to meet the requirements of high horizontal angle resolution and long-distance ranging, multiple channels need to emit light simultaneously. Moreover, the higher the horizontal angle resolution and the farther the ranging requirement, the more the number of simultaneously emitting channels. The inventors of the present invention found that for high-line-beam lidars, the channel arrangement is dense, and the more the number of simultaneously emitting channels, the more likely optical crosstalk occurs. This crosstalk has an acceptable impact on detecting distant targets, but when measuring nearby targets, the mutual interference between channels is very serious. From the perspective of the point cloud, it means that the ranging of targets is inaccurate and the channel consistency is poor at close range.

[0079] As Figure 4A and 4B shown, when all channels of a high-line-beam lidar emit light for ranging when detecting nearby targets, both the vertical and horizontal angle resolutions are excessive. As Figure 4A shown, since the different lines of the lidar are radially divergent, when detecting distant targets, due to the far distance, the laser spots scanned on the target can be clearly separated. Due to the far distance, the laser reflected back to the lidar is basically parallel light, and the position of the spot on the focal plane is less affected by the distance. Therefore, for the scanning of distant objects, all channels of the lidar and its maximum performance can be maximally utilized at this time. When detecting nearby targets, the radially divergent distance of the laser beam is short. Therefore, the trajectories scanned by each laser beam on the target are dense, so there is serious spot stacking and redundancy. Considering the drift and dispersion of the near-range spots, it not only wastes the laser beam but also affects the measurement accuracy of the lidar.

[0080] Therefore, according to an embodiment of the present invention, the control unit 102 is configured to emit light from a relatively large number of lasers in the first mode to improve the resolution of a distant target; meanwhile, in the second mode, a relatively small number of channels are used to measure a nearby target, and the number of simultaneously emitting channels is minimized when measuring the nearby target, preferably a single channel, to reduce the interference between the simultaneously emitting channels, thereby greatly improving the accuracy of the nearby measurement. Specifically, the first mode includes: controlling n lasers in the laser array 101 to emit light, where n is less than or equal to N, and N is the total number of lasers in the laser array; the second mode includes controlling k lasers in the laser array to emit light, where the k lasers are selected from the n lasers and k is less than n. Preferably, n is equal to the total number of lasers N in the laser array. Preferably, the second mode is single-channel light emission. Preferably, the n lasers emit light simultaneously, and the k lasers also emit light simultaneously. In an embodiment of the present invention, for example, the total number of lasers in the laser array 101 is 8 (N = 8). In the first mode, 8 lasers in the laser array 101 are controlled to emit light, preferably the 8 lasers emit light simultaneously. In the second mode, 2 lasers in the laser array 101 are controlled to emit light, preferably the 2 lasers emit light simultaneously, or preferably, in the second mode, 1 laser in the laser array 101 emits light in a single channel, further reducing channel crosstalk.

[0081] In an embodiment of the present invention, the first mode includes: at each horizontal angle position of the lidar, controlling the n lasers in the laser array to emit light; the second mode includes: at the same horizontal angle position as the first mode, controlling the k lasers in the laser array to emit light. For example, as described above, the horizontal angle resolution of the lidar is 0.2°. Each horizontal angle of the lidar, that is, every 0.2°, starts from 0° and triggers at angles such as 0°, 0.2°, 0.4°... That is, at each angle of 0°, 0.2°, 0.4°..., the laser array 101 performs light emission ranging in the first mode and the second mode. Of course, the horizontal angle resolution of the lidar can also be 0.1° or other angles, which is set according to the detection requirements.

[0082] In the above description, only the case where the laser array 101 includes 8 lasers is used as an example to simply illustrate the first mode and the second mode. High-line lidars can usually achieve 40, 64, 128, and even higher line numbers. Due to the constraints of the detection distance and the horizontal angle resolution, high-line lidars usually need to emit light in multiple groups in sequence, and each group of laser arrays is a sub-laser array.

[0083] According to a preferred embodiment of the present invention, the laser array is divided into m groups that emit light sequentially, where m is an integer and m > 1. The control unit is configured to control each group of the laser array to emit a first detection laser beam in a first mode, and is configured to control each group of the laser array to emit a second detection laser beam in a second mode before or after emitting the first detection laser beam in the first mode. At each horizontal angle position of the lidar, the m sub-laser arrays all complete light emission according to the mode. Preferably, the order of the first mode and the second mode of these m sub-arrays is the same. For example, for these m sub-laser arrays, the first mode is performed first and then the second mode. The m groups emitting light sequentially means that in chronological order, after one group is completed, the next group of operations is carried out. Preferably, in each sub-laser array, the lasers emitting light in each mode can emit light simultaneously, and the lasers emitting light in the second mode can emit light simultaneously. According to an embodiment of the present invention, when the number of grouped m is relatively large, the number of lasers emitting light in the second mode in some sub-laser arrays can be equal to 0.

[0084] The following will be described in detail with reference to the accompanying drawings.

[0085] Figure 5 The logical arrangement (light emission timing sequence) of multiple lasers of the laser array 101 is shown, where the laser array 101 includes 128 lasers as an example for illustration. Generally, for lidars with high beam numbers, when controlling the light emission timing sequence, multiple lasers need to emit light in parallel. As Figure 3 shown, 128 lasers can be divided into 16 groups, with 8 lasers in each group emitting light simultaneously, and a total of 16 emissions can complete the emission of 128 lasers. Figure 5 In the horizontal direction is the order of the light emission moments. The lasers are divided into 16 groups, with 8 lasers in each group. For convenience, the numbers of the 8 lasers emitting light at the first moment are 1-1, 1-2, …, 1-7, 1-8, and the numbers of the 8 lasers emitting light at the 16th moment are 16-1, 16-2, …, 16-7, 16-8. The lasers emitting light at the remaining moments are numbered similarly, which will not be elaborated here. The 128 lasers are triggered by the same horizontal angle.

[0086] According to an embodiment of the present invention, the laser array 101 is a laser array formed by a single laser or a linear array laser or a planar array laser, and the laser includes an edge-emitting laser or a vertical cavity surface-emitting laser or a combination of both.

[0087] Those skilled in the art can easily understand that Figure 5 the lasers are numbered and arranged according to the logical order of light emission therein, and it can be consistent or inconsistent with the Figure 2 and Figure 3 shown physical arrangement of the lasers. For example Figure 2Two lasers in the same column can have different emission times in Figure 5 which are all within the protection scope of the present invention.

[0088] In the present invention, the first mode and the second mode are relative concepts, and the number of lasers used in the first mode is more than that used in the second mode. According to a preferred embodiment of the present invention, the first mode is a long-distance measurement mode, and all the lasers in the laser array 101 are used to emit light alternately for detection; the second mode is a short-distance measurement mode, and some of the lasers in the laser array 101 are used to emit light alternately for detection. It is easy for those skilled in the art to understand that even in the first mode, instead of using all the lasers to emit light alternately, some lasers can be used to emit light (i.e., n is less than N), as long as the number of emitting lasers in the first mode is more than that in the second mode. For convenience and clarity, in the following description, the case where all the lasers are used to emit light in the first mode will be taken as an example for illustration.

[0089] According to an embodiment of the present invention, the control unit 102 can control the k lasers in the laser array, so that these k lasers emit a second detection laser beam in the second mode before or after emitting a first detection laser beam in the first mode. The control unit 102 can preset a selection method to select or randomly select the k lasers that emit light in the second mode, and perform an emission according to the second mode once before or after the k lasers emit light in the first mode.

[0090] Figure 5 The situation where the emission in the second mode is after the emission in the first mode is shown. Figure 5 In the shown emission unit including 128 lasers, 8 lasers are selected, and their numbers are 1-1, 3-1, 4-2, 5-3, 7-4, 9-5, 10-3, and 12-1 respectively. During the normal long-distance measurement (first mode), after these 8 lasers complete the long-distance measurement, an additional short-distance emission (second mode) is performed. Figure 6 The long-distance emission and short-distance emission of one of the lasers are shown therein, where the green block is the long-distance light emission time window, and the yellow block is the short-distance light emission time window. Therefore, 8 short-distance emissions are inserted during the rotation of light emission for long-distance measurement in 128 channels. In addition, each short-distance emission is preferably single-channel light emission, that is, only one laser emits light according to the second mode at the same moment.

[0091] In addition, the present invention is not limited to the number of the selected partial lasers. Figure 5Eight lasers are shown for emitting the second detection laser beam. The specific number can be more than eight or less than eight, which is determined according to the desired horizontal angular resolution for near-distance measurement. In addition, the part of the lasers emitted in the second mode can be pre-set or generated in real time. For example, for the eight lasers at each emission moment in Figure 5 , one laser can be randomly selected from them to implement the emission in the second mode, and all these are within the protection scope of the present invention.

[0092] Figure 5 and Figure 6 shows that for the k lasers, the emission in the second mode is after the emission in the first mode. Alternatively, the emission in the second mode can also be carried out before the emission in the first mode, as shown in Figure 7 . Before the k lasers emit according to the first mode, they first emit according to the second mode to detect nearby targets. This will not be elaborated here.

[0093] In an embodiment of the present invention, when the distance between the target and the lidar is 5 - 200 m, it is in the far-distance measurement mode (i.e., the ranging result is used to provide the three-dimensional point cloud data for lidar far-distance measurement), and the number of lasers emitted in the far-distance measurement mode is large. When the distance between the target and the lidar is within 5 m, it is in the near-distance measurement mode (i.e., the ranging result is used to provide the three-dimensional point cloud data for lidar near-distance measurement), and the number of lasers emitted in the near-distance measurement mode is small. The present invention is not limited to the above specific values and can also be modified and adjusted according to specific situations. For example, the distance preset value is determined according to the spot offset and dispersion degree varying with distance obtained from the lens parameters of the lidar and the system's recognition ability for the detector output signal. The setting of the distance preset value is used as a reference for the lidar to output three-dimensional point cloud data, which will be described in detail below.

[0094] According to a preferred embodiment of the present invention, in order to distinguish the first detection laser beam emitted in the first mode and the second detection laser beam emitted in the second mode, the first detection laser beam and the second detection laser beam can have different pulse codings. For example, both the first detection laser beam and the second detection laser beam can adopt double pulses, but the double pulses of the two have different time intervals for coding, so that at the receiving end, it can be distinguished whether the echo corresponds to the first detection laser beam or the second detection laser beam according to the interval of the echo pulses. Preferably, the first detection laser beam and the second detection laser beam can also adopt triple pulses.

[0095] In addition, the first detection laser beam and the second detection laser beam can also be distinguished by the signals read through different time windows reserved by the detectors corresponding to each channel. For example, in the case where the second mode follows the first mode, if the first detection laser beam in the first mode is used for long-distance measurement, the detector (after the laser in this channel emits light in the first mode) reserves a relatively long first time window for receiving the echo reflected by the first detection laser beam from the target. After the first mode completes the long-distance measurement, a relatively short second time window is reserved for receiving the echo of the second detection laser beam for short-distance measurement in the second mode. Therefore, the first detection laser beam and the second detection laser beam are distinguished by reading the signals of the first time window and the second time window of the detectors in each channel. Then, according to the time point when the first detection laser beam or the second detection laser beam is emitted, the time of flight TOF is obtained, multiplied by the speed of light c and then divided by 2, and the distance between the target and the lidar can be obtained. The long-distance measurement mode is, for example, > 3m, corresponding to a tof time (time window) of t > 20ns, while the short-distance measurement mode is, for example, ≤ 3m, corresponding to a tof time (time window) of t ≤ 20ns.

[0096] According to another embodiment of the present invention, the possible distances between the target and the lidar can also be calculated respectively based on the detected echo and the time points when the first detection laser beam and the second detection laser beam are emitted. Then, it is determined whether the echo signal corresponds to the first detection beam or the second detection beam (for example, it can be determined according to the specific expected detection distance corresponding to each detection beam), and the distance of the target is determined from the two possible distances.

[0097] The lidar usually has a rotating shaft and can rotate in a plane around the rotating shaft. For convenience, the description is made with the lidar vertically installed, that is, the rotating shaft is along the vertical direction, the lidar can rotate in the horizontal plane, and during the rotation process, the driving laser emits a detection laser beam. The lidar has a certain angular resolution, for example, 0.1° or 0.2°, and a detection laser beam is emitted at each horizontal angular position of the lidar (for example, at intervals of the horizontal angular resolution of the lidar). Figure 8 It shows that the angular resolution of the lidar is 0.1°, that is, detection is performed every 0.1°.

[0098] According to a preferred embodiment of the present invention, the first mode includes: controlling the n lasers in the laser array to emit light at each horizontal angular position of the lidar; the second mode includes: controlling some of the lasers in the laser array to emit light at the same horizontal angular positions as the first mode. As Figure 8 (a)-(d) shows, at each horizontal angular position of the lidar, in addition to performing the light emission detection in the first mode, the light emission detection in the second mode is also performed through the k lasers.

[0099] As Figure 8 described in [reference], 128 lasers are divided into 16 groups for emitting light, and each group of laser arrays (i.e., sub-laser arrays) includes 8 lasers. In the first mode, n lasers in each group of laser arrays are controlled to emit light, where the maximum value of n is the total number of lasers in each group of laser arrays (sub-laser arrays). For example, in the first mode, all 8 lasers in this group are controlled to emit light. Subsequently, in the second mode, only a few lasers in each group of laser arrays emit light, such as 1 laser. In chronological order, after one group is completed, the next group is operated. Taking Figure 8 (a) as an example, the laser numbers in the second mode are 1-1, 3-1, 4-2, 5-3, 7-4, 9-5, 10-3, 12-1 (refer to Figure 5 ), and the lasers in the second mode are all selected from different groups, thereby further reducing the possibility of optical crosstalk. In this embodiment, 128 lasers are evenly grouped. Of course, they can also be non-uniformly grouped according to actual situations, that is, the number of lasers in each group of laser arrays can be different.

[0100] Additionally, preferably, at two adjacent horizontal angle positions of the lidar, the partial lasers emitting the second detection laser beam are different from each other, and the second mode cycles with s horizontal angles of the lidar as a period, where s is an integer greater than or equal to 2. As shown in Figure 8 (a), the partial laser numbers at 0.0° are 1-1, 3-1, 4-2, 5-3, 7-4, 9-5, 10-3, 12-1; as shown in Figure 8 (b), the partial laser numbers at 0.1° are 1-2, 2-7, 3-6, 5-5, 7-2, 10-7, 13-4, 14-6. Among them, the partial lasers emitting light in the second mode at 0.0 and 0.1° do not overlap. The selection method of the second-mode lasers tries to ensure that different-position lasers among the 128 lasers are utilized in batches as fully as possible, so as to fully guarantee the field of view and resolution of near-distance detection.

[0101] Taking Figure 8Taking the lidar with 128 lines shown as an example, 8 channels emit light simultaneously, for a total of 16 times, and the horizontal resolution is 0.1°. When measuring distance normally, after the distance measurement is completed on certain specific channels, a close-range measurement is added once. 8 close-range measurements are inserted during each round of light emission for distance measurement by 128 channels. Each close-range measurement preferably emits light through a single channel. Among four 0.1° intervals, 8 different close-range measurement channels are selected. In this way, within a 0.4° cycle, the signal transmission and reception of 32 close-range measurement channels are completed. Therefore, the distance measurement of this lidar is 128 lines, with a horizontal angular resolution of 0.1°, while the close-range measurement is 32 lines, with a horizontal angular resolution of 0.4°. Different coded pulses can be used for distance measurement and close-range measurement to distinguish the echo signals of distance measurement and close-range measurement and avoid misidentification. Figure 8 The light emission sequence arrangement for close-range measurement and distance measurement of the 128-line lidar is illustrated. The green blocks are the time windows for distance measurement light emission, and the yellow blocks are the time windows for close-range measurement light emission. The close-range measurement is arranged to emit light once again for close-range measurement after the distance measurement is completed on this channel.

[0102] Alternatively, 16 close-range measurements are inserted during each round of light emission for distance measurement by 128 channels. Each close-range measurement preferably emits light through a single channel. Among two 0.1° intervals, 16 different close-range measurement channels are selected. In this way, within a 0.2° cycle, the signal transmission and reception of 32 close-range measurement channels are completed. Therefore, the distance measurement of this lidar is 128 lines, with a horizontal angular resolution of 0.1°, while the close-range measurement is 32 lines, with a horizontal angular resolution of 0.2°.

[0103] The second mode may not be 32 lines, but a higher or lower number of lines, which is set according to the actual situation.

[0104] Those skilled in the art understand that in the present invention, the high-line laser does not necessarily emit light in groups sequentially, but can also emit light simultaneously. For example, in one case, the laser array 101 includes 128 lasers. In the first mode, for example, 128 lasers can simultaneously emit the first detection laser beam (through appropriate optoelectronic isolation, used to provide distance measurement data (with relatively less influence on distance measurement optical crosstalk)), and in the second mode, for example, multiple lasers (such as 8, 16, less than 128 with relatively separated vertical fields of view) are selected to emit the second detection laser beam, for example, for close-range measurement (to provide close-range measurement data). Such an embodiment is also within the protection scope of the present invention.

[0105] Based on the above analysis, an embodiment of the present invention proposes a solution in which the long-distance and short-distance measurements of the lidar are independently alternated. When measuring long distances, all channels (or most channels) are opened to measure medium and far targets; when measuring short distances, only some channels are opened, and the horizontal scanning frequency is reduced, so that only a few channels or even a single channel emit light simultaneously each time, which can greatly reduce the near-distance optical crosstalk, or even completely avoid the optical crosstalk. In this way, the lidar has a high number of beams and high horizontal angular resolution when measuring medium and long distances, and a low number of beams and low horizontal angular resolution when measuring short distances. However, this does not significantly reduce the resolution ability of nearby targets, because the detection and recognition of nearby targets themselves require a low number of beams and angular resolution. Excessive number of beams and excessive horizontal angular resolution may even form spot stacking and generate redundancy at close range.

[0106] The present invention also relates to a lidar, as Figure 9 shown, which will be described below with reference to the drawings.

[0107] As Figure 9 shown, the lidar 10 includes the above-mentioned transmitting unit 100, receiving unit 120, and control unit 130. The transmitting unit 100 can alternately transmit the first detection laser beam and the second detection laser beam L1 / L2 to the outside of the lidar 10 according to a first mode and a second mode, where the number of lasers used in the first mode is more than the number of lasers used in the second mode, for example, for measuring long distances and short distances respectively. The first detection laser beam and the second detection laser beam are diffusely reflected on the target OB, and the radar echoes L1' / L2' return to the lidar and are received by the receiving unit 120. The receiving unit 200 includes a detector array, such as an array of detectors such as APD, SiPM, SPAD, etc. The detector array is configured to receive the echoes after the first detection laser beam and the second detection laser beam are reflected by the target and convert the echoes into electrical signals. The control unit 130 is coupled to the detector array and is configured to read the electrical signals output by the detector array, determine whether the electrical signals correspond to the first detection laser beam or the second detection laser beam, calculate the distance of the target according to the electrical signals, and generate point cloud data according to the distance and the determination result.

[0108] Those skilled in the art can easily understand that the receiving unit 120 and the control unit 130 can be configured as separate modules or integrated into an overall module, and these are all within the protection scope of the present invention. In addition, in order to calculate the distance between the target and the lidar based on the time-of-flight ranging method (TOF), the control unit 130 can be coupled to the transmitting unit 100, so as to record the emission times of the first detection laser beam and the second detection laser beam. Of course, it is also feasible to obtain the emission time by other means, which will not be elaborated here.

[0109] According to the lidar of the present invention, the long-range and short-range measurements of the high-line-beam lidar can be independently and alternately performed. When performing long-range measurement, the highest line beam and angular resolution are adopted, while when performing short-range measurement, a lower line beam and angular resolution are adopted, so that the number of simultaneously emitting channels during short-range measurement is reduced, thereby reducing the optical crosstalk at close range.

[0110] The present invention also relates to a ranging method 200 using the lidar 10 as described above, as Figure 10A shown and will be described below with reference to the accompanying drawings.

[0111] In step S201: Control the laser array to emit a first detection laser beam in a first mode, where the first mode includes: controlling n lasers in the laser array to emit light, n is less than or equal to N, and N is the total number of lasers in the laser array; the first mode is, for example, a long-range measurement mode, and preferably all the lasers in the laser array are enabled to sequentially emit the first detection laser beam.

[0112] In step S202: Control some of the lasers in the laser array to emit a second detection laser beam in a second mode before or after emitting the first detection laser beam in the first mode. The second mode includes controlling k lasers in the laser array to emit light, where the k lasers are selected from the n lasers and k is less than n; the second mode is, for example, a short-range measurement mode, and for example, some of the lasers in the laser array can be enabled to sequentially emit the second detection laser beam.

[0113] Preferably, the n is equal to the total number N of lasers in the laser array. Preferably, the second mode is single-channel light emission. Preferably, the n lasers emit light simultaneously, and the k lasers also emit light simultaneously.

[0114] In step S203: Receive the echo of the detection laser beam reflected by the target and convert the echo into an electrical signal, and calculate the distance between the target and the lidar according to the electrical signal. For example, according to the reception time of the echo and the emission time of the detection laser beam, based on the time-of-flight ranging method (TOF, distance = time of flight * speed of light / 2), the distance between the target and the lidar can be obtained.

[0115] In step S204: Determine whether the electrical signal corresponds to the first detection laser beam or the second detection laser beam.

[0116] In step S205: Generate point cloud data based on the distance and the judgment result. For example, when it is determined that the electrical signal corresponds to the first detection laser beam (long-distance measurement mode), if the distance between the target object and the lidar calculated based on this electrical signal is less than the preset distance value (for example, 5 meters), since this electrical signal is used for long-distance measurement, this electrical signal can be selected not to be used or discarded and not used for generating point cloud data. Conversely, when it is determined that the electrical signal corresponds to the second detection laser beam (short-distance measurement mode), if the distance between the target object and the lidar calculated based on this electrical signal is greater than the preset distance value (for example, 5 meters), since this electrical signal is used for short-distance measurement, this electrical signal can be selected not to be used or discarded and not used for generating point cloud data. Use the data stitching of the long-distance and short-distance measurement modes to generate more accurate three-dimensional point cloud data.

[0117] According to an embodiment of the present invention, step S202 includes: controlling the k lasers in the laser array to emit a second detection laser beam in a second mode after emitting a first detection laser beam in the first mode, as Figure 5 and Figure 6 shown. Alternatively, step S202 includes: controlling some of the lasers in the laser array to emit a second detection laser beam in a second mode before emitting a first detection laser beam in the first mode, as Figure 7 shown.

[0118] According to an embodiment of the present invention, the first mode includes: controlling the n lasers in the laser array to emit light at each horizontal angle position of the lidar; the second mode includes: controlling the k lasers in the laser array to emit light at the same horizontal angle position as the first mode. According to an embodiment of the present invention, the laser array is divided into m groups that emit light in sequence, where m is an integer and m>1. Control each group of the laser array to emit a first detection laser beam in the first mode, and control each group of the laser array to emit a second detection laser beam in the second mode before or after emitting the first detection laser beam in the first mode.

[0119] According to an embodiment of the present invention, at two adjacent horizontal angle positions of the lidar, the partial lasers that emit the second detection laser beam are different from each other, and the second mode cycles with s horizontal angles of the lidar as a period, where s is an integer greater than or equal to 2.

[0120] According to an embodiment of the present invention, the first detection laser beam and the second detection laser beam have different pulse codings, so that according to different pulse codings, at the receiving end, it can be distinguished whether the radar echo corresponds to the first detection laser beam or the second detection laser beam, and corresponding processing operations can be performed.

[0121] According to an embodiment of the present invention, the step S204 includes: judging whether the electrical signal corresponds to the first detection laser beam or the second detection laser beam through the time window for receiving the echo.

[0122] In order to distinguish the first detection laser beam and the second detection laser beam, the first detection laser beam and the second detection laser beam may have different pulse codings. For example, both the first detection laser beam and the second detection laser beam can adopt double pulses, but the double pulses of the two have different time intervals for coding, so that at the receiving end, according to the interval of the echo pulses, it can be distinguished whether the echo corresponds to the first detection laser beam or the second detection laser beam. In addition, the first detection laser beam and the second detection laser beam can also be distinguished by the signals read through different time windows reserved by the detectors corresponding to each channel. For example, for the case where the second mode is after the first mode, the first detection laser beam of the first mode is used for distance measurement, then the detector (after the laser of this channel emits light according to the first mode) reserves a longer first time window for receiving the echo reflected from the target by the first detection laser beam, and reserves a shorter second time window for receiving the echo of the second detection laser beam for short-distance measurement in the second mode after the first mode completes distance measurement. Therefore, the first detection laser beam and the second detection laser beam are distinguished by reading the signals of the first time window and the second time window of the detectors of each channel.

[0123] Figure 10B Another method 200' for ranging using the lidar 10 as described above is shown, in which the first detection laser beam and the second detection laser beam with different pulse codings are used. The following will be described with reference to Figure 10B in detail.

[0124] Step S201' and step S202' are respectively substantially the same as Figure 10A steps S201 and S202 in, and will not be elaborated here.

[0125] In step S203', according to the pulse coding of the echo, it is determined whether the echo corresponds to the first detection laser beam or the second detection laser beam. Since the first detection laser beam and the second detection laser beam have different pulse codings, the echoes generated by the first detection laser beam and the second detection laser beam also have corresponding pulse codings, and according to the pulse coding, it can be distinguished whether the echo corresponds to the first detection laser beam or the second detection laser beam.

[0126] In step S204', according to the judgment result of step S203', the distance of the target is calculated according to the time point when the first detection laser beam or the second detection laser beam is emitted. If the echo corresponds to the first detection laser beam, the emission time point of the first detection laser beam is used to calculate the flight time and the distance of the target; otherwise, the emission time point of the second detection laser beam is used to calculate the flight time and the distance of the target.

[0127] In step S205', point cloud data is generated according to the distance.

[0128] Based on the above analysis, the present invention proposes a solution of independently and alternately performing long-distance measurement and short-distance measurement of a lidar. When performing long-distance measurement, all channels are opened to measure medium and far targets; when performing short-distance measurement, only some channels are opened and the horizontal scanning frequency is reduced, so that only a few channels or even a single channel emit light simultaneously each time, which can greatly reduce the near-distance optical crosstalk and even completely avoid optical crosstalk. In this way, the lidar has a high beam number and high horizontal angular resolution when measuring medium and long distances, and a low beam number and low horizontal angular resolution when measuring short distances. However, this does not significantly reduce the resolution ability of nearby targets, because the detection and recognition of nearby targets themselves require a low beam number and low horizontal angular resolution. Excessively high beam numbers and high angular resolutions may even form spot stacking and generate redundancy at close range.

[0129] When performing long-distance measurement, all channels being opened can be understood as all lasers emitting light in turn during long-distance measurement, and within the range of this long-distance measurement, the detectors of all channels obtain valid data corresponding to the time window. When performing short-distance measurement, opening some channels can be understood as some lasers emitting light in turn during short-distance measurement, and within the range of this short-distance measurement, the detectors of some channels obtain valid data corresponding to the time window. Different encodings can be used during long-distance and short-distance measurements to distinguish the echo signals of long-distance and short-distance measurements and avoid misidentification.

[0130] The present invention independently and alternately performs long-distance measurement and short-distance measurement of a high-beam-number lidar. When performing long-distance measurement, the highest beam number and resolution are used, while when performing short-distance measurement, a lower beam number and resolution are used, so that the number of channels emitting light simultaneously during short-distance measurement is reduced, thereby reducing the optical crosstalk at close range. For example: The long-distance measurement and short-distance measurement of a high-beam-number lidar are independently and alternately performed. When performing long-distance measurement, the highest beam number and resolution are used, while when performing short-distance measurement, a lower beam number and resolution are used, so that the number of channels emitting light simultaneously during short-distance measurement is reduced.

[0131] From the above facts, it can be inferred that a lidar can use a large number of channels to emit light in parallel to improve the resolution of distant targets; at the same time, a small number of channels are used to measure nearby targets, and the number of channels emitting light simultaneously during short-distance measurement is minimized as much as possible to reduce the interference between channels emitting light simultaneously, greatly improving the accuracy of near-distance measurement.

[0132] The second aspect

[0133] Based on the first aspect of the present invention, according to the results of the lidar's close-range detection, the far-field light intensity when the lidar scans the same position or a nearby position next time can be feedback-controlled, which can significantly reduce the light intensity of the lasers in the far-field mode or even turn off the light emission in the far-field mode to reduce the power consumption of the lidar. The following is a detailed description.

[0134] In the embodiments of the present invention, when the lidar detects a target object at close range, the light emission of the lasers in the far-field mode has a relatively small effect compared to the light emission of the lasers in the close-range mode. Therefore, reducing the light intensity of the far-field mode and keeping the light intensity of the close-range mode unchanged can reduce the overall power consumption of the lidar without affecting the close-range detection ability. Specifically, according to the results of the close-range detection during the first detection, when scanning the corresponding angular range next time, the light intensity of the lasers in the far-field mode can be significantly reduced or even turned off, which can reduce the power consumption of the lidar when there is a target object at close range. The following is a detailed description with reference to the accompanying drawings.

[0135] Figure 11 A control method 300 of a lidar according to an embodiment of the present invention is shown. The control method 300 can be implemented by the lidar described in the first aspect of the present invention. More specifically, the lidar implementing the control method 300 includes a laser array having N lasers. The control method 300 includes the following steps.

[0136] In step S301: Control n lasers to emit a first detection laser beam, and control k lasers among them to emit a second detection laser beam; where n ≤ N, and the k lasers are selected from the n lasers, and k < n. In a specific implementation, the first detection laser beam can be emitted before the second detection laser beam or after the second detection laser beam. If the first detection laser beam is used for far-field detection, the light intensity of the first detection laser beam can be greater than that of the second detection laser beam.

[0137] Taking the horizontal angular resolution of the lidar as 0.2° as an example, starting from 0°, the lidar triggers at angles of 0°, 0.2°, 0.4°... respectively, and performs a cycle of detection (detection cycle) at each angle. During each cycle, the lidar executes as Figure 5The light detection shown. It is also easy to understand that at each angle of the lidar, multiple lasers of the lidar emit light, preferably in groups in sequence. However, since the switching speed of multiple groups of lasers to emit light is significantly higher than the rotation speed of the lidar, it is approximately that multiple lasers emit light at this angle (although there is actually a certain angular displacement). The first detection laser beams emitted by the n lasers usually have a higher intensity, so they are used for the long-distance measurement mode (the first mode), and the second detection laser beams emitted by the k lasers have a lower intensity and are usually used for the short-distance measurement mode (the second mode).

[0138] Reference Figure 5 , in the emission unit including 128 lasers, 8 lasers are selected, and their numbers are 1-1, 3-1, 4-2, 5-3, 7-4, 9-5, 10-3, 12-1 respectively. After the emission in the normal long-distance measurement mode, these 8 lasers all append an emission in the short-distance measurement mode. Therefore, 8 short-distance measurements are inserted during the rotation of 128 channels to emit light for long-distance measurement. In addition, Figure 5 , in [reference], for the selected 8 lasers, the emission of the first detection laser beam is after the emission of the second detection laser beam. The present invention is not limited to this, and the emission of the first detection laser beam can also be before the emission of the second detection laser beam, as shown in Figure 7 .

[0139] In step S302: Receive the echoes reflected by the first detection laser beam and the second detection laser beam on the target object.

[0140] After the first detection laser beam and the second detection laser beam are diffusely reflected on the target object, part of the reflected light beams (echoes) return to the lidar and are received by the detectors of the receiving unit of the lidar and converted into electrical signals.

[0141] In step S303: Calculate the distance of the target object according to the echo.

[0142] According to the echo and the emission time point of the detection laser beam corresponding to the echo, the distance of the target object can be calculated.

[0143] The first detection laser beam and the second detection laser beam may have different pulse codings. For example, both the first detection laser beam and the second detection laser beam can adopt double pulses, but the double pulses of the two have different time intervals for coding. Thus, at the receiving end, according to the interval of the echo pulses, it can be determined whether the echo corresponds to the first detection laser beam or the second detection laser beam. Then, according to the time point when the first detection laser beam or the second detection laser beam is emitted, the distance of the target object can be calculated. For example, both the first detection laser beam and the second detection laser beam are double pulses. The time interval between the first pulse p1 and the second pulse p2 of the first detection laser beam is Δt1, and the time interval between the first pulse p1 and the second pulse p2 of the second detection laser beam is Δt2. If two pulses with an interval of Δt1 are received before and after, it can be determined that they correspond to the first detection laser beam; similarly, if two pulses with an interval of Δt2 are received before and after, it can be determined that they correspond to the second detection laser beam. Another example, for instance, both the first detection laser beam and the second detection laser beam are triple pulses. The time interval between the first pulse p1 and the second pulse p2 of the first detection laser beam is Δt1, and the time interval between the second pulse p2 and the third pulse p3 of the first detection laser beam is Δt1”. The time interval between the first pulse p1 and the second pulse p2 of the second detection laser beam is Δt2, and the time interval between the second pulse p2 and the third pulse p3 of the second detection laser beam is Δt2”. If three pulses are received before and after, with intervals of Δt1 and Δt1” in sequence, it can be determined that they correspond to the first detection laser beam; similarly, if three pulses are received before and after, with intervals of Δt2 and Δt2” in sequence, it can be determined that they correspond to the second detection laser beam.

[0144] Alternatively, the first detection laser beam and the second detection laser beam can also be distinguished by the signals read through different time windows reserved by the detectors corresponding to each channel. For example, in the case where the second detection laser beam is emitted after the first detection laser beam, the detector can reserve a longer first time window (after the first detection laser beam is emitted from the laser of this channel) for receiving the echo reflected from the target object by the first detection laser beam, and then reserve a shorter second time window for receiving the echo of the second detection laser beam. Therefore, through the first time window and the second time window of the detectors of each channel, it can be determined whether the echo corresponds to the first detection laser beam or the second detection laser beam. Then, according to the time point when the first detection laser beam or the second detection laser beam is emitted, the time of flight TOF is obtained, multiplied by the speed of light c and then divided by 2, and the distance between the target object and the lidar can be obtained. According to a preferred embodiment of the present invention, the long-distance measurement and the short-distance measurement can be decomposed by 3 meters. When the distance between the target object and the lidar is greater than 3 meters, it belongs to long-distance measurement, corresponding to a TOF time of more than 20 ns. When the distance between the target object and the lidar is less than 3 meters, it belongs to short-distance measurement, corresponding to a TOF time within 20 nm.

[0145] Preferably, n = N. In the long - range detection mode, all the lasers in the laser array emit light alternately for detection. Correspondingly, the receiving end starts to receive the echo signal, but the signals within a duration of TOF ≤ 20 ns are directly filtered out without further processing. In the short - range detection mode: some of the lasers in the laser array 101 emit light alternately for detection. Correspondingly, the receiving end starts to receive the echo signal, but only the signals within a duration of TOF ≤ 20 ns are received, and based on these signals, further processing is carried out to detect the actual distance and reflectivity of possible objects within 3 m from the lidar.

[0146] According to another embodiment of the present invention, the possible distance between the target object and the lidar can also be calculated respectively based on the detected echo and the time points when the first detection laser beam and the second detection laser beam are emitted. Then, it is determined whether the echo signal corresponds to the first detection beam or the second detection beam (for example, judged according to the specific expected detection distance corresponding to each detection beam), and the distance of the target object is determined from the two possible distances.

[0147] In step S304: when a target object is detected within a preset distance, in the next detection cycle, the luminous intensity of at least some of the n lasers emitting the first detection laser beam is reduced within the range corresponding to the target object.

[0148] When it is detected that the target object is within the preset distance, it indicates that there is a short - range target object. Therefore, in the next detection cycle, when the lidar rotates to the angular range corresponding to this target object, the luminous intensity of at least some of the n lasers emitting the first detection laser beam in the long - range detection mode can be reduced, thereby saving power consumption and reducing crosstalk. Regarding the range of the preset distance, it can be determined according to the usage scenario and technical parameters of the lidar. For example, within 5 meters from the lidar can be considered within the preset distance, and beyond 5 meters is outside the preset distance.

[0149] According to a preferred embodiment of the present invention, the angular range approximately corresponding to the next scan of the same object can also be predicted based on the type and motion parameters of the target object and the detection parameters of the lidar, and the luminous intensity of the first detection laser beam is reduced within the predicted angular range. For example, according to the type of the target object (dynamic or static), motion speed, direction, rotation speed of the lidar, or the angular velocity of the internal galvanometer / mirror in the lidar, etc., the angular range when the lidar scans the object next time can be predicted, and the luminous intensity of the first detection laser beam is reduced.

[0150] Therefore, according to the second aspect of the present invention, the first detection laser beam in the long-range detection mode and the second detection laser beam in the short-range detection mode can be independently separated. According to the feedback of the detection result, the emission intensity of the first detection laser beam is adjusted accordingly (for example, if there is an object at a short distance, the light intensity of the first detection laser beam is reduced; if there is no object, the light intensity of the first detection laser beam remains unchanged), while the emission intensity of the second detection laser beam can be not adjusted. In this way, the luminous power consumption of long-range detection can be reduced without weakening the short-range detection ability.

[0151] Figure 12a The detection strategy of the lidar according to the second aspect of the present invention is shown. Figure 12a The top view of the lidar is shown, where the lidar rotates in the plane of the paper along the direction indicated by the arrow. Figure 12a Multiple lines in it represent the detection laser beams emitted when the lidar rotates to different positions (angles). Among them, the thick solid line represents the first detection laser beam (strong) with a higher emission intensity, the thin solid line represents the first detection laser beam (weak) with a lower emission intensity, and the dashed line represents the second detection laser beam. As shown in Figure 12a When detecting for the first time, the lidar emits the first detection laser beam with a normal relatively high emission intensity. At the same time, for some of the lasers, the second detection laser beam is emitted before or after the emission of the first detection laser beam, and according to the echo, it is determined that there is an object at a position relatively close to the lidar. Correspondingly, when the lidar rotates to the position corresponding to the target object next time, the lidar can reduce the light intensity of the first detection laser beam emitted by the lasers. In this way, the power consumption of the lidar is reduced, while the emission intensity of the second detection laser beam in the short-range detection mode is not affected, and it is still possible to ensure that objects nearby can be detected. Therefore, as shown in Figure 12b it is still possible to ensure that the echo generated by the reflection of the nearby object is higher than the threshold Th.

[0152] According to a preferred embodiment of the present invention, according to the distance of the target object, the angular range α of the target object within the preset distance is obtained (as shown in Figure 12b ), and the emission light intensity of the lasers within the angular range α among the n lasers for emitting the first detection laser beam in the next detection cycle is reduced. After one detection cycle of the lidar, according to the point cloud, the angular range α of the target object can be roughly judged. For example, at the edge position of the angular range α (as shown in Figure 12bAt the left and right edges of the middle angular range α, the distance corresponding to the point cloud changes abruptly, that is, the distances of the points within this angular range are smaller, and outside this angular range, the distances of the points suddenly increase. In this way, the angular range of the nearby object can be roughly outlined. Alternatively, in the next detection cycle, some of the n lasers within the angular range α can be turned off. Figure 12b Only the angular range α of the target object in the horizontal direction is shown in the figure, and the angular range of the target object in the vertical direction can also be obtained, which will not be elaborated here.

[0153] According to the method for controlling a lidar proposed in the second aspect of the present invention, if an object is detected nearby during the first scan, when the same angle is scanned the next time (the second time), the light intensity of the first detection laser beam is reduced to reduce the radar power consumption, while not reducing the light intensity for detecting nearby objects by the radar. Therefore, whether it is the first detection or the second detection, nearby objects can be detected. According to a preferred embodiment of the present invention, the normal light emission intensity of the first detection laser beam in the far-detection mode ( Figure 12a In the left figure, the far-detection laser (strong)) is twice the light emission intensity of the second detection laser beam in the near-detection mode. When designing the working parameters of the lidar, it can be ensured that the light emission intensity of the second detection laser beam is lower than the human eye safety threshold, and the light emission intensity of the second detection laser beam is higher than the light intensity of the reduced first detection laser beam ( Figure 12a In the right figure, the far-detection laser (weak)).

[0154] In the lidar according to the second aspect of the present invention, if there is an object within a preset distance from the lidar, then the second detection laser beam emitted by the laser will detect the object. As Figure 13a shown, which shows that the first detection laser beam and the second detection laser beam emitted during the first detection detect an object at a short distance, where the size of the light spot is used to characterize the relative size of the laser light intensity, which may not match or may match the actual size of the emitted light spot. The detected point cloud map can continue to refer to the above Figure 12b . It can be seen that the lateral (horizontal direction) and longitudinal (vertical direction) resolutions generated by the second detection laser beam are very likely to be lower than those generated by the first detection laser beam. Specifically, in the Figure 13a right-side scan light spot map, it can be seen that within the range of the nearby object, the lateral resolution generated by the second detection laser beam is approximately half (3 / 7) of the lateral resolution generated by the first detection laser beam, and the longitudinal resolution generated by the second detection laser beam is approximately half (2 / 4) of the longitudinal resolution generated by the first detection laser beam.

[0155] Based on the detection results of the lidar, the angular range (horizontal angle and vertical angle) of nearby objects can be calculated, and then the luminous intensity when all channels within this angular range emit the first detection laser beam is reduced. For example, Figure 13b as shown, when the position corresponding to the nearby target object is scanned for the second time, the luminous intensity of the first detection laser beam is reduced. However, since the luminous intensity of the second detection laser beam remains unchanged, the point cloud map obtained from the second detection can still be used for the above Figure 12b , so it is possible to ensure that the lidar does not lose its detection ability at close range while reducing power consumption.

[0156] Regarding step S304, preferably, the angular range of nearby objects can be outlined by calculating the influence domain of each near-measurement point cloud. The so-called influence domain can be the range of the point cloud (or beam bundle) affected by the near-distance detection results of each near-measurement point cloud. In a lidar, one (or more) lasers and one detector form a detection channel. For example, when a certain detection channel detects an object at close range at a certain horizontal angle position in the near-measurement mode, then this detection channel will transmit this information to the surrounding detection channels, conveying the information of "there is an object at close range at the current position" to the surrounding detection channels. Then, after these surrounding detection channels receive this information, they will reduce the luminous intensity of the long-distance measurement within this angular range. As follows Figure 15 shown. The division of the influence domain can be made using the midline between two near-measurement point clouds, so that the position of each long-distance measurement point cloud can be notified.

[0157] In addition, since the nearby objects detected by the lidar may be living beings, according to an embodiment of the present invention, the strategy of reducing the luminous intensity of the long-distance measurement mode can be adopted in advance and cancelled later. In other words, before reaching the angular range of the near-distance object, the luminous intensity of the long-distance measurement can be reduced in advance, and when the angular range of the near-distance object has been left, a relatively low luminous intensity of the long-distance measurement is still maintained. The advance and delay ranges can be set in a preset manner.

[0158] Figure 14 shows the working method 400 of the lidar.

[0159] In step S401, the lidar performs the first detection, emitting detection laser beams in the long-distance measurement mode + near-measurement mode respectively.

[0160] In step S402, it is determined whether there are nearby objects. If there are nearby objects, it proceeds to step S403; otherwise, it proceeds to step S405. Regarding the range of close distance, it can be determined according to the usage scenario and technical parameters of the lidar. For example, within 5 meters from the lidar can be considered as close range, and beyond 5 meters is not considered as close range.

[0161] In step S403, calculate the angular range of the nearby object, such as the angular range in the horizontal direction and the angular range in the vertical direction.

[0162] In step S404, perform a second detection. That is, when the lidar rotates to the angular range of the nearby object next time, reduce the emission intensity of the long-range detection mode, and emit detection laser beams in the long-range detection mode + short-range detection mode.

[0163] In step S405, if there is no nearby object, when the lidar rotates to the same angular range next time, there is no need to change the emission intensity of the long-range detection mode, and still emit detection laser beams in the combination of the long-range detection mode + short-range detection mode.

[0164] Regarding step S403, preferably, the influence domain of each short-range point cloud can be calculated to outline the angular range of the nearby object. The so-called influence domain can be the range of the point cloud (or beam bundle) affected by the short-range detection result of each short-range point cloud. In a lidar, a laser and a detector form a detection channel. For example, if a certain detection channel detects a nearby object at a certain horizontal angular position in the short-range detection mode, then this detection channel will transmit this information to the surrounding detection channels, conveying the information of "there is a nearby object at the current position" to the surrounding detection channels. Then, after these surrounding detection channels receive this information, they will reduce the long-range light intensity within this angular range. As follows Figure 15 shown. The division of the influence domain can be made using the midline between two short-range point clouds so that the position of each long-range point cloud can be notified.

[0165] In addition, since the nearby object detected by the lidar may be a living body, therefore, according to an embodiment of the present invention, the strategy of reducing the emission light intensity of the long-range detection mode can be adopted in advance and cancelled later. In other words, before reaching the angular range of the nearby object, the long-range light intensity can be reduced in advance, and when leaving the angular range of the nearby object, a relatively low long-range light intensity can still be maintained. The advance and delay ranges can be set in a preset manner.

[0166] According to an embodiment of the present invention, during the second detection, within the angular range of the nearby object, some long-range channels can be selected to be turned off (or the horizontal angular resolution can be reduced, refer to Figure 16 ), or the vertical angular resolution can be reduced, refer to Figure 17 , rather than reducing the emission light intensity of the long-range detection mode of all lasers. It is also possible to combine reducing the horizontal angular resolution and reducing the vertical angular resolution at the same time.

[0167] The second aspect of the present invention also relates to a lidar, the structure of which is shown in FIG. 10, including a transmitting unit 100 (including a laser array 101 composed of N lasers), a receiving unit 120, and a control unit 130. The laser array 101 is configured to emit detection laser beams. The receiving unit 120 includes a detector array, which can receive the echo reflected by the detection laser beam on the target and convert it into an electrical signal. The control unit is coupled to the laser array and the receiving unit, and is configured to calculate the distance of the target according to the electrical signal, and can control n lasers to emit the first detection laser beam, and control k lasers among them to emit the second detection laser beam; where n≤N, the k lasers are selected from the n lasers, k < n, and the optical intensity of the first detection laser beam is greater than that of the second detection laser beam; where the control unit is configured to: when a target is detected within a preset distance, reduce the emission optical intensity of at least some of the n lasers emitting the first detection laser beam within the range corresponding to the target in the next detection cycle..

[0168] The control unit 130 can execute the control method of the lidar as described above. For example, the control unit can obtain the angular range of the target within the preset distance according to the distance of the target output by the control unit, and reduce the emission optical intensity of the lasers within the angular range among the n lasers emitting the first detection laser beam in the next detection cycle. The control unit can obtain the angular range of the target within the preset distance according to the distance of the target output by the control unit, and turn off the emission of the first detection laser beam of some of the lasers within the angular range among the n lasers in the next detection cycle.

[0169] According to a preferred embodiment of the present invention, p lasers and one detector form a detection channel, p≥1, and the control unit is configured to: when a target within a preset distance is detected in one of the detection channels, control the lasers of the detection channels within a preset range around the detection channel to reduce the emission optical intensity of the first detection laser beam in the next detection cycle.

[0170] According to a preferred embodiment of the present invention, the preset range is divided according to the midline between two near-measurement point clouds.

[0171] According to a preferred embodiment of the present invention, the control unit is configured to: obtain the angular range of the target within the preset distance according to the distance of the target output by the control unit, and reduce the emission optical intensity of the lasers within the angular range and within a preset range adjacent to the angular range emitting the first detection laser beam in the next detection cycle.

[0172] According to a preferred embodiment of the present invention, the control unit is configured to: correct the angular range in the next detection period according to one or more of the type of the target object, the motion parameters, and the detection parameters of the lidar.

[0173] According to an embodiment of the present invention, compared with the second detection laser beam, the first detection laser beam is used to measure a target object at a farther distance. The N lasers are divided into m groups and emit light in sequence, where m is an integer and m > 1. The control unit is configured to: at each horizontal angle position of the lidar, control n lasers in each group of laser arrays to emit the first detection laser beam; at the same horizontal angle position, control the k lasers in the laser array to emit the second detection laser beam before or after emitting the first detection laser beam.

[0174] According to an embodiment of the present invention, the first detection laser beam and the second detection laser beam have different pulse codings;

[0175] The control unit is configured to: determine that the echo corresponds to the first detection laser beam or the second detection laser beam according to different pulse codings, and calculate the distance of the target object according to the time point of emitting the first detection laser beam or the second detection laser beam.

[0176] According to an embodiment of the present invention, the control unit is configured to: judge whether the echo corresponds to the first detection laser beam or the second detection laser beam through the time window for receiving the echo, and calculate the distance of the target object according to the time point of emitting the first detection laser beam or the second detection laser beam.

[0177] According to an embodiment of the present invention, the control unit is configured to: respectively calculate the possible distances between the target object and the lidar according to the detected echo and the time points of emitting the first detection laser beam and the second detection laser beam; judge whether the echo signal corresponds to the first detection laser beam or the second detection laser beam, and determine the distance of the target object.

[0178] The present invention also relates to a computer-readable storage medium, including computer-executable instructions stored thereon, and the executable instructions implement the control method as described above when executed by a processor.

[0179] Through the embodiments of the present invention, when using the short-distance detection result to feedback the next time scanning to the nearby position, the light intensity of the laser for measuring the distance can be greatly reduced or even turned off, and the radar power consumption can be reduced in the case of having a target object at a short distance.

[0180] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A control method for a lidar, wherein the lidar includes a laser array having N lasers, and the control method comprises: S301: Controlling n lasers to emit first detection laser beams, and controlling k lasers among them to emit second detection laser beams; where n ≤ N, the k lasers are selected from the n lasers, k < n, and the optical intensity of the first detection laser beam is greater than that of the second detection laser beam; S302: Receiving the echoes reflected by the first detection laser beam and the second detection laser beam on the target; S303: Calculating the distance of the target according to the echo; and S304: When a target is detected within a preset distance, reducing the emission optical intensity of at least some of the n lasers emitting the first detection laser beam within the range corresponding to the target in the next detection cycle.

2. The control method according to claim 1, wherein the step S304 comprises: Obtaining the angular range of the target within the preset distance according to the distance of the target, and reducing the emission optical intensity of the lasers within the angular range among the n lasers emitting the first detection laser beam in the next detection cycle.

3. The control method according to claim 1 or 2, wherein the step S304 comprises: Obtaining the angular range of the target within the preset distance according to the distance of the target, and turning off some of the lasers within the angular range among the n lasers in the next detection cycle.

4. The control method according to claim 2, wherein p lasers and one detector form a detection channel, p ≥ 1, and the step S304 comprises: When a target within the preset distance is detected in one of the detection channels, controlling the lasers of the detection channels within a preset range around the detection channel to reduce the emission optical intensity of the first detection laser beam in the next detection cycle.

5. The control method according to claim 4, wherein the preset range is divided according to the midline between two near-point clouds.

6. The control method according to claim 1, wherein the step S304 comprises: Correcting the angular range corresponding to the target in the next detection cycle according to one or more of the type of the target, the motion parameters, and the detection parameters of the lidar.

7. The control method according to claim 1, wherein the N lasers are divided into m groups and emit light in sequence, m is an integer and m > 1, and the step S101 comprises: At each horizontal angular position of the lidar, controlling n lasers in each group of the laser array to emit first detection laser beams; At the same horizontal angular position, controlling the k lasers in the laser array to emit second detection laser beams before or after emitting the first detection laser beams.

8. The control method according to claim 1, wherein the first detection laser beam and the second detection laser beam have different pulse encodings; Step S303 includes: determining, according to different pulse codings, that the echo corresponds to the first detection laser beam or the second detection laser beam, and calculating the distance of the target object according to the time point when the first detection laser beam or the second detection laser beam is emitted.

9. The control method according to claim 1, wherein the step S303 includes: Judging, through the time window for receiving the echo, whether the echo corresponds to the first detection laser beam or the second detection laser beam, and calculating the distance of the target object according to the time point when the first detection laser beam or the second detection laser beam is emitted.

10. The control method according to claim 1, wherein the step S303 includes: Respectively calculating the possible distances between the target object and the lidar according to the detected echo and the time points when the first detection laser beam and the second detection laser beam are emitted; Judging whether the echo corresponds to the first detection laser beam or the second detection laser beam, and determining the distance of the target object.

11. A lidar, comprising: A laser array having N lasers, configured to emit detection laser beams; A receiving unit, including a detector array, configured to receive the echo reflected by the detection laser beam on the target object and convert it into an electrical signal; and A control unit, coupled to the laser array and the receiving unit, configured to calculate the distance of the target object according to the electrical signal, and control n lasers to emit the first detection laser beam, and control k lasers among them to emit the second detection laser beam; where n ≤ N, the k lasers are selected from the n lasers, k < n, and the optical intensity of the first detection laser beam is greater than that of the second detection laser beam; wherein the control unit is configured to: when a target object is detected within a preset distance, reduce the optical intensity of at least some of the n lasers emitting the first detection laser beam within the range corresponding to the target object in the next detection cycle.

12. The lidar according to claim 11, wherein the control unit is configured to: obtain the angular range of the target object within the preset distance according to the distance of the target object, and reduce the optical intensity of the lasers within the angular range among the n lasers emitting the first detection laser beam in the next detection cycle.

13. The lidar according to claim 11 or 12, wherein the control unit is configured to: obtain the angular range of the target object within the preset distance according to the distance of the target object, and turn off the emission of the first detection laser beam of some of the n lasers within the angular range in the next detection cycle.

14. The lidar according to claim 12 or 13, wherein p lasers and one detector form a detection channel, p ≥ 1, and the control unit is configured to: when a target object within the preset distance is detected by one of the detection channels, control the lasers of the detection channels within a preset range around the detection channel to reduce the optical intensity of the first detection laser beam emitted in the next detection cycle.

15. The lidar according to claim 14, wherein the preset range is divided according to the midline between two adjacent point clouds.

16. The lidar according to claim 12, wherein the control unit is configured to: obtain an angular range of the target object within a preset distance according to the distance of the target object output by the control unit, and reduce the emission intensity of the lasers within the angular range and within a preset range adjacent to the angular range in the long-range detection mode in the next detection cycle.

17. The lidar according to claim 13, wherein the control unit is configured to: correct the angular range in the next detection cycle according to one or more of the type of the target object, the motion parameters, and the detection parameters of the lidar.

18. The lidar according to claim 12, wherein compared with the second detection laser beam, the first detection laser beam is used to measure a target object at a farther distance, the N lasers are divided into m groups and emit light in sequence, m is an integer and m>1, and the control unit is configured to: at each horizontal angular position of the lidar, control n lasers in each group of laser arrays to emit the first detection laser beam; at the same horizontal angular position, control the k lasers in the laser array to emit the second detection laser beam before or after emitting the first detection laser beam.

19. The lidar according to claim 12, wherein the first detection laser beam and the second detection laser beam have different pulse codings; The control unit is configured to: determine that the echo corresponds to the first detection laser beam or the second detection laser beam according to different pulse codings, and calculate the distance of the target object according to the time point of emitting the first detection laser beam or the second detection laser beam.

20. The lidar according to claim 11, wherein the control unit is configured to: judge whether the echo corresponds to the first detection laser beam or the second detection laser beam through the time window for receiving the echo, and calculate the distance of the target object according to the time point of emitting the first detection laser beam or the second detection laser beam.

21. The lidar according to claim 11, wherein the control unit is configured to: respectively calculate the possible distances between the target object and the lidar according to the detected echo and the time points of emitting the first detection laser beam and the second detection laser beam; judge whether the echo corresponds to the first detection laser beam or the second detection laser beam, and determine the distance of the target object.

22. A computer-readable storage medium, including computer-executable instructions stored thereon, the executable instructions, when executed by a processor, implement the control method according to any one of claims 1-10.

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