WO2022042079A1 - 激光雷达及其发射模组、接收模组、探测方法 - Google Patents

激光雷达及其发射模组、接收模组、探测方法 Download PDF

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Publication number
WO2022042079A1
WO2022042079A1 PCT/CN2021/105551 CN2021105551W WO2022042079A1 WO 2022042079 A1 WO2022042079 A1 WO 2022042079A1 CN 2021105551 W CN2021105551 W CN 2021105551W WO 2022042079 A1 WO2022042079 A1 WO 2022042079A1
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WIPO (PCT)
Prior art keywords
laser
wavelength
lasers
lidar
module
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PCT/CN2021/105551
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English (en)
French (fr)
Inventor
刘兴伟
孙恺
朱雪洲
向少卿
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上海禾赛科技有限公司
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Publication of WO2022042079A1 publication Critical patent/WO2022042079A1/zh

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G01S7/4811—Constructional features, e.g. arrangements of optical elements common to transmitter and receiver
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/42—Simultaneous measurement of distance and other co-ordinates
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Definitions

  • the embodiments of this specification relate to the technical field of laser radar, and in particular, to a transmitting module, a receiving module, a related control method, and a laser radar.
  • the laser beam (ie the detection beam) is emitted through the transmitting module, and the laser beam (ie the echo beam) reflected by the target is received by the receiving module, and the receiving module converts the optical signal of the echo beam After being an electrical signal, three-dimensional point cloud data can be obtained through signal processing.
  • the lasers in the transmitting module are located at different positions of the transmitting focal plane, and the detectors in the receiving module are correspondingly located at different positions on the receiving focal plane. Therefore, the lasers can emit beams of different angles to the outside world, and the detectors can receive The beams reflected from different angles from the outside world, so as to realize the spatial measurement of different angles.
  • the transmitting module needs to activate multiple lasers, and correspondingly, the receiving module needs to activate multiple detectors. Based on the distribution positions of the activated detectors, the echo beams of the corresponding lasers can be respectively received.
  • the laser wavelengths emitted by each laser in the lidar transmitting module are the same, and there may be crosstalk between multiple detectors activated at the same time, so that the detection unit in one detector may also receive other simultaneously activated channel bands. The interference noise of the same wavelength will cause a ranging error.
  • the embodiments of this specification provide a transmitting module, a receiving module, a detection method, and a laser radar, which can improve the anti-interference ability between multiple detectors and effectively ensure the signal receiving performance of the laser radar.
  • the embodiments of this specification provide a laser radar transmitter module, including: a plurality of lasers, the emission wavelengths of the lasers include a first wavelength and a second wavelength, and the lasers suitable for simultaneous emission have different emission wavelengths.
  • a plurality of lasers with the same wavelength constitute a laser group, and the number of the laser group is determined based on the highest number of beams simultaneously emitted by the lidar.
  • the lasers in the same laser group do not fire simultaneously.
  • the laser includes one or more light-emitting units, which are adapted to emit laser beams, and the wavelengths of the multiple lasers emitted at the same time are different.
  • the laser includes: one or more light-emitting units and a wavelength converter, wherein: the wavelength converter is adapted to convert the wavelength of the laser beam emitted by the light-emitting unit to a wavelength required by the corresponding laser.
  • the arrangement of the plurality of lasers includes: arranging in a linear array; arranging in a rectangular array.
  • the wavelength of each laser is positively related to the distance between the laser and a designated position, and the designated position is located in a plane perpendicular to the horizontal central axis of the lidar.
  • the wavelength of the laser close to the designated position is lower than the wavelength of the laser relatively far from the designated position.
  • the wavelength difference of the plurality of lasers and the wavelength deviation error of the lasers with temperature satisfy the following relationship:
  • ⁇ 1 and ⁇ 2 are the first wavelength and the second wavelength of the laser, respectively, ⁇ is the temperature drift coefficient of the laser, ⁇ T is the maximum temperature difference in the working process of the laser, and ⁇ is the spectral width of the laser.
  • the wavelength difference of the plurality of lasers and the bandwidth of the filter in the receiving module of the laser radar satisfy the following relationship:
  • ⁇ 1 and ⁇ 2 are the first wavelength and the second wavelength of the laser, respectively, ⁇ 0 is the filter bandwidth of the filter, and ⁇ is the spectral width of the laser.
  • Embodiments of the present specification further provide a receiving module for a laser radar, including: a plurality of detectors, each of which is suitable for an echo beam of a laser beam emitted by a corresponding laser in the above-mentioned transmitting module and reflected by a target.
  • the receiving module further includes a filter, and the filter transmits a laser beam having the same wavelength as the corresponding laser in the incident light.
  • the filter bandwidth of the filter is set according to the wavelength of the corresponding laser and the maximum drift error of the wavelength.
  • the arrangement of the detectors includes: arranging in a linear array; arranging in a rectangular array.
  • Embodiments of this specification further provide a laser radar, including the above-mentioned laser radar transmitting module, the above-mentioned laser radar receiving module, and a controller, wherein: the controller is adapted to control one or more of the lasers Each emits laser beams, and controls one or more corresponding detectors to receive echo beams of the laser beams reflected by the target.
  • the relative arrangement position of the lasers in the transmitting module is consistent with the relative arrangement position of the corresponding detector in the receiving module.
  • the embodiments of this specification also provide a detection method for a laser radar, which is applied to the above-mentioned laser radar.
  • the detection method includes: A1) Based on the wavelength and position information corresponding to each of the lasers, control the laser according to a preset emission control sequence Emitting light to ensure that the lasers emitted at the same time can emit laser beams of different wavelengths; A2) Control each detector in the receiving module to receive incident light that matches the wavelength of the corresponding laser.
  • Embodiments of this specification further provide a lidar, including: a memory, adapted to store one or more computer-executable instructions; a controller, adapted to call one or more computer-executable instructions in the memory to execute the above-mentioned Detection method steps.
  • the transmitting module in the lidar may include multiple lasers, and the emitting wavelengths of the lasers include a first wavelength and a second wavelength, wherein the laser that emits a laser beam of the first wavelength is the first laser , the laser that emits the laser beam of the second wavelength is the second laser, and the first laser and the second laser are suitable for emitting light simultaneously, so that the simultaneously emitting lasers can emit laser beams of different wavelengths;
  • the receiving module in the lidar may include A plurality of detectors, wherein the detectors can receive incident light corresponding to the emission wavelength of the laser.
  • the detector can only receive the echo beams that match the emitting wavelengths of the corresponding lasers.
  • the echoes caused by receiving beams from other lasers can be avoided. Therefore, the crosstalk between the simultaneously activated detectors can be avoided, and the interference noise caused by the external ambient light can be reduced, thereby improving the anti-interference ability between multiple detectors and effectively ensuring the signal receiving performance of the lidar.
  • FIG. 1 is a schematic structural diagram of a transmitting and receiving module of a laser radar in an embodiment of the present specification.
  • FIG. 2 is a schematic structural diagram of another transmitting and receiving module of a laser radar in an embodiment of the present specification.
  • FIG. 3 is a schematic diagram of an arrangement of lasers in a linear array according to an embodiment of the present specification.
  • FIG. 4 is a schematic diagram of a laser arrangement in a rectangular array according to an embodiment of the present specification.
  • FIG. 5 is a schematic diagram of a staggered arrangement of lasers in an embodiment of the present specification.
  • FIG. 6a is a schematic diagram of a wavelength setting method of a laser group in an embodiment of the present specification.
  • FIG. 6b is a schematic diagram of the laser groups in FIG. 6a being arranged in a staggered manner.
  • FIG. 7 is a schematic diagram of a staggered arrangement of laser mounting boards in an embodiment of the present specification.
  • FIG. 8 is a schematic structural diagram of a receiving module in an embodiment of the present specification.
  • FIG. 9 is a schematic structural diagram of a laser radar in an embodiment of the present specification.
  • FIG. 10 is a flowchart of a method for controlling a transmitting module of a laser radar in an embodiment of the present specification.
  • FIG. 11 is a flowchart of a method for controlling a receiving module of a laser radar in an embodiment of the present specification.
  • the laser beam is emitted by the transmitting module, and the laser beam (ie the echo beam) reflected by the target is received by the receiving module.
  • the receiving module converts the optical signal of the echo beam into an electrical signal, After signal processing, 3D point cloud data can be obtained.
  • the lasers in the transmitting module are located at different positions of the transmitting focal plane, and the detectors in the receiving module are correspondingly located at different positions on the receiving focal plane. Therefore, the lasers can emit light beams of different angles to the outside world, and the detectors can Receive light beams reflected from different angles from the outside world, so as to realize spatial measurement of different angles.
  • a diaphragm can be set on the receiving focal plane to filter out stray light, and detectors can be set behind the diaphragm along the downstream of the optical path to reduce noise and improve the signal-to-noise ratio.
  • the transmitting module needs to activate multiple lasers at the same time to emit multiple laser beams at the same time.
  • the receiving module needs to activate multiple detectors at the same time to receive the laser beams emitted by the corresponding lasers respectively.
  • the receiving optical components in the lidar are not ideal, there may be crosstalk between multiple detectors activated at the same time, so that the detectors may also receive echo beams corresponding to other detectors, increasing the interference noise; The echo beams corresponding to other detectors misjudge the target echo beams obtained by the detection beam of the laser corresponding to this detector, causing defects such as ghost images.
  • lasers 1 and 2 are activated to emit laser beams at the same time, and detectors 1 and 2 respectively receive the echo beams corresponding to laser 1 (that is, the laser beams emitted by laser 1 are reflected by the target and return to the lidar) and the corresponding laser beams.
  • the echo beam of 2 (that is, the laser beam emitted by the laser 2 is reflected by the target and returned to the laser beam of the lidar), when the detector 1 receives the echo beam corresponding to the laser 1, the other detector 2 can also receive it.
  • a small amount corresponds to the stray light of the echo beam of the laser 1 .
  • Detector 1 can be regarded as the interference source channel
  • Detector 2 can be regarded as the interfered channel
  • Detector 2 is affected by the interference of Detector 1, and there is crosstalk between Detector 1 and Detector 2.
  • the stronger the intensity of the optical signal received by the interference source channel the greater the degree of influence of the interference on the interfered channel.
  • the interfered channel may receive strong interference noise from the interference source.
  • a strong interference noise may cause interference to multiple detectors activated at the same time; on the other hand, if the interference noise is strong enough to exceed the echo detection threshold of the interfered channel, it will cause " False points", the combination of multiple false points will form ghost images.
  • the wavelength of the laser beam emitted by the laser is the same, the wavelength of the echo beam that the disturbed channel actually needs to obtain and the stray light of the disturbing source channel are the same. echo information, which in turn leads to errors in the determination of flight time, resulting in a decrease in measurement accuracy.
  • the embodiments of this specification provide a laser radar transceiver solution.
  • the laser radar transmitter module includes multiple lasers, and the laser beams emitted by the lasers emitted at the same time have different wavelengths; the laser radar receiver module can be The corresponding activation detectors receive incident light, and each detector only receives a laser beam that matches the wavelength of the corresponding laser.
  • the stray light incident on the detector can be made different from the wavelength of the echo beam of the corresponding laser by emitting laser beams of different wavelengths by the lasers emitted at the same time. Filter out the stray light and only receive the laser beam echo of the corresponding laser, thus avoiding the crosstalk between the detectors activated at the same time, and can reduce the interference noise caused by the external ambient light, thereby improving the anti-interference between multiple detectors It can effectively guarantee the signal receiving performance of lidar.
  • FIG. 1 is a schematic structural diagram of a transmitting and receiving module of a laser radar in an embodiment of the present specification.
  • the lidar 10 may include: a transmitting module 11 and a receiving module 12 .
  • the laser emission and reception operations can be performed respectively through the emission module 11 and the reception module 12 .
  • the emission module 11 may include: n lasers 111, 112-11n and an emission optical assembly 11a.
  • the emission module 11 is provided with lasers of two wavelengths, wherein the laser 111 can output a laser beam 11A with a wavelength of ⁇ 1 when activated, and the laser 112 can output a laser beam 11B with a wavelength of ⁇ 2 when activated,
  • the lasers 113 and 114 to 11n can output a laser beam 11A with a wavelength of ⁇ 1 when activated.
  • the laser beam After the activated laser outputs a laser beam, the laser beam is collimated by the transmitting optical component 11a, and then emitted to the outside world. After being reflected by the external target 1x, the reflected echo beam enters the receiving module 12.
  • the laser emitted by the laser in the transmitting module 11 has two wavelengths ⁇ 1 and ⁇ 2, there are two lasers in the transmitting module 11 that are suitable for simultaneous emission, and can simultaneously activate two lasers outputting laser beams of different wavelengths.
  • the lasers 111 and 112 emit light at different wavelengths, then the lasers 111 and 112 can be activated to emit simultaneously, so that the laser 111 emits a laser beam 11A with a wavelength of ⁇ 1, and the laser 112 emits a wavelength of ⁇ 2. the laser beam 11B.
  • the laser beam with wavelength ⁇ 1 and the laser beam with wavelength ⁇ 2 are collimated by the emission optical component 11a, they are emitted to the outside world.
  • the reflected laser beam with wavelength ⁇ 1 and the laser beam with wavelength ⁇ 2 are reflected.
  • the laser beam enters the receiving module 12 .
  • the laser 112 is different from the lasers 111, 113-11n. Therefore, any one of the laser 112 and the lasers 111, 113-11n can be activated at the same time, so that the two lasers emitted at the same time emit Laser beams of different wavelengths.
  • the receiving module 12 may also receive external ambient light and stray light caused by echoes of the corresponding wavelengths of other detectors. Therefore, the incident light of the receiving module 12 may also include: interference noise from ambient light and other detections. interference noise from the device.
  • the receiving module 12 may include m detectors 121-12m and a receiving optical assembly 12a, wherein the detectors 121-12m can receive incident incident light obtained by focusing processing by the optical assembly 12a.
  • Light 12A The lasers 111 to 11n and the detectors 121 to 12m have a corresponding relationship of sending and receiving, that is, according to the activated lasers, the corresponding activated detectors can be determined. According to the corresponding relationship between the laser and the detector, the corresponding activation detector can be used to receive the laser beam matching the wavelength of the laser.
  • the laser 111 corresponds to the detector 121, and if the laser 111 is activated, the corresponding activation detector 121 is used to receive a laser beam matching the wavelength ⁇ 1 of the laser 111; the laser 112 corresponds to the detector 122, and if the laser 112 is activated, the corresponding The activation detector 122 is used to receive a laser beam matching the wavelength ⁇ 2 of the laser 112 .
  • the lidar 20 may include: a transmitting module 21 and a receiving module 22 .
  • the laser transmitting and receiving operations can be carried out respectively through the transmitting module 21 and the receiving module 22 .
  • the difference between the lidar 20 shown in FIG. 2 is that it includes a plurality of lasers with different wavelengths.
  • the laser 211 can output a laser beam with a wavelength of ⁇ 1 when activated
  • the laser 212 can output a laser beam with a wavelength of ⁇ 2 when activated
  • the laser 213 can output a laser beam with a wavelength of ⁇ 3 when activated...
  • the laser 21n is activated It can output a laser beam with a wavelength of ⁇ n; ⁇ 1 ⁇ n are all different wavelength length values, that is, ⁇ 1 ⁇ n are not equal to each other.
  • the emitting module 21 is provided with n lasers with wavelengths ⁇ 1 to ⁇ n, there are at most n lasers in the emitting module 21 that are suitable for simultaneous emission.
  • the multiple lasers emitted at the same time can emit laser beams of different wavelengths, thus, the incident light received by the receiving module 22 includes corresponding laser beams of different wavelengths .
  • the wavelength of the laser beam 21B output by the laser 211 is ⁇ 1
  • the wavelength of the laser beam 21A output by the laser 212 is ⁇ 2. Therefore, when the lasers 211 and 212 are activated for simultaneous emission, the lasers 211 and 212 The laser beams of different wavelengths are respectively emitted. After the laser beam with wavelength ⁇ 1 and the laser beam with wavelength ⁇ 2 are collimated by the transmitting optical component 21a, they are emitted to the outside world. After being reflected by the external target 2x, the reflected laser beam with wavelength ⁇ 1 and the laser beam with wavelength ⁇ 2 are reflected. The laser beam enters the receiving module 22 .
  • the wavelength of the laser beam 21B output by the laser 212 is ⁇ 2
  • the wavelength of the laser beam 21C output by the laser 213 is ⁇ 3
  • the wavelength of the laser beam 21D output by the laser 214 is ⁇ 4
  • the wavelengths are respectively ⁇ 2
  • the laser beams of ⁇ 3 and ⁇ 4 are collimated by the transmitting optical component 215, they are emitted to the outside world.
  • the reflected wavelengths are respectively ⁇ 2, ⁇ 3 and ⁇ 4.
  • the laser beams enter the receiving module twenty two.
  • the receiving module 22 may also receive external ambient light and stray light caused by echoes of the corresponding wavelengths of other detectors. Therefore, the incident light of the receiving module 22 may also include: interference noise from ambient light and other detections. interference noise from the device.
  • the receiving module 22 may include m detectors 221-22m and a receiving optical assembly 22a, wherein the detectors 221-22m can receive incident incident light obtained by focusing processing by the optical assembly 22a.
  • Light 22A There is a corresponding relationship between the lasers 211-21n and the detectors 221-22m, that is, according to the activated lasers, the corresponding activated detectors can be determined. According to the corresponding relationship between the laser and the detector, the corresponding activation detector can be used to receive the laser beam matching the wavelength of the laser.
  • the laser 211 corresponds to the detector 221. If the laser 211 is activated, the corresponding activation detector 221 is used to receive a laser beam matching the wavelength ⁇ 1 of the laser 211; the laser 212 corresponds to the detector 222, and if the laser 212 is activated, it corresponds to The activation detector 222 is used to receive a laser beam matching the wavelength ⁇ 2 of the laser 212 .
  • the incident light may include multiple laser beams with different wavelengths, and each detector in the multiple simultaneously activated detectors only receives the wavelength matching the corresponding laser. Therefore, through wavelength matching, it can avoid receiving stray light from the corresponding lasers of other detectors.
  • the ambient light is usually visible light, its wavelength is usually different from the wavelength of the laser beam. Therefore, after setting the wavelength matching the detector, the interference of the ambient light to the detector can be reduced.
  • the number of detectors is the same as the number of lasers, that is, the lasers and the detectors are in one-to-one correspondence, and the wavelength of the laser beam emitted by the laser in the same transceiver channel as the detector is configured as the wavelength of the laser beam emitted by the detector. matching wavelength.
  • the number of wavelengths corresponding to the emission module can be configured according to requirements.
  • the number of wavelengths can be the same as the number of lasers, or less than the number of lasers.
  • the wavelengths of each laser do not need to be different, and some lasers with the same wavelength may exist, which is not limited in this embodiment of the present specification.
  • grouping can also be performed according to the number of lasers that are emitted at the same time. For details, please refer to the descriptions in the following relevant parts, which will not be repeated here.
  • the lidar can set the activation of lasers and detectors when performing laser transceiver operations according to actual application scenarios and requirements. quantity.
  • the number of lidar lasers and detectors, as well as the wavelengths corresponding to the lasers and detectors can also be set according to actual application scenarios and requirements. There is no specific limitation on this in the embodiments of the present specification.
  • the lidar may also include other hardware modules, hardware circuits, etc., for example, the lidar may also include a control module, a scanning module, and The adaptation circuit of each module, etc., wherein the adaptation circuit may include: a signal reading circuit and a power supply circuit that provides power for each module, etc.
  • the specific structure of the lidar is not limited in this specification.
  • the laser radar provided by the embodiments of the present specification includes a transmitting part and a receiving part.
  • the transmitting part of the laser radar is first described below.
  • the laser includes one or more light-emitting units adapted to emit a laser beam.
  • the light-emitting unit includes at least one of the following types: 1) Vertical-Cavity Surface-Emitting Laser (VCSEL); 2) Edge Emitting Laser (EEL).
  • VCSEL Vertical-Cavity Surface-Emitting Laser
  • EEL Edge Emitting Laser
  • a laser can include a VCSEL array formed by multiple VCSELs, and emit light by activating multiple VCSELs in the VCSEL array at the same time, and shaping into a laser beam through the emission optical component
  • the luminous efficiency of a single EEL is relatively high, and when a single EEL meets the lighting requirements, a laser may contain one EEL.
  • a plurality of lasers can be arranged in a regular arrangement, and can also be arranged in an irregular arrangement, for example, a plurality of lasers are arranged in a linear array or in a matrix, thereby obtaining a laser array;
  • a plurality of lasers are arranged in an irregular arrangement in the vertical direction with dense distances in the middle and sparse ends at both ends.
  • the plurality of lasers may be arranged at a fixed pitch or may be arranged at a non-fixed pitch. This manual does not set the arrangement of multiple lasers.
  • the wavelength of the laser beam emitted by the laser has a certain distribution range, that is, the spectral width of the laser.
  • the wavelength with the maximum optical energy is set as the center wavelength of the laser, that is, the wavelength of the laser.
  • a laser marked to emit a laser beam with a wavelength of 1550 nm may actually have a wavelength distribution range of 1549-1551 nm, with a central wavelength of 1550 nm.
  • the center wavelength of the laser beam actually output by the laser will drift with the temperature change.
  • the wavelength of the laser beam actually output by each laser undergoes temperature drift. It may be that lasers originally corresponding to different wavelengths have the same wavelength of the laser beam output under the influence of temperature, so that in the lasers emitted at the same time, There may be lasers that output the same wavelength after temperature drift.
  • the wavelength spacing between different wavelengths can be greater than the maximum wavelength drift error of the emission module with temperature changes, so as to ensure that when the wavelength of the laser output laser beam has temperature drift, the drifted The wavelength is also different from the wavelength of the laser beam output by other lasers.
  • the temperature drift coefficient of VCSEL is 0.07nm/C°. If the temperature range of the laser is [-40°C, +120°C] during the operation of the lidar, the maximum wavelength drift of the laser with temperature changes is 11.2nm , the wavelength spacing between different wavelengths is greater than 11.2nm, which can ensure that the wavelength of the laser beam output by the laser is also different from the wavelength of the laser beam output by other lasers after drift.
  • the wavelength-dependent offset error can be determined by the wavelength-temperature drift and the spectral width in a certain temperature range.
  • the temperature drift coefficient of VCSEL is 0.07nm/C°. If the temperature range is [-40°C, +120°C], the maximum wavelength drift of the laser with temperature changes is 11.2nm, and the spectral width is 1nm, then the laser The wavelength shift error with temperature changes is 12.2nm, and the wavelength spacing between different wavelengths is greater than 12.2nm to ensure that the wavelength of the laser output laser beam is different from the wavelength of the laser beam output by other lasers after the drift.
  • the wavelength spacing and the laser wavelength deviation error with temperature satisfy the following relationship:
  • ⁇ 1 and ⁇ 2 are the first wavelength and the second wavelength of the laser, respectively, ⁇ is the temperature drift coefficient of the laser, ⁇ T is the maximum temperature difference in the working process of the laser, and ⁇ is the spectral width of the laser.
  • the wavelength spacing can be an integer, such as 15nm, 20nm, 25nm, etc.
  • the light-emitting unit corresponding to the wavelength can be selected according to the wavelength spacing. For example, if the wavelength spacing of the laser is 20nm, the wavelength used by each laser can be They are 850nm, 870nm, 890nm, etc. respectively. Moreover, after the wavelength spacing between the detectors satisfies the condition of being greater than the maximum drift error of the wavelength, the wavelength spacing between the detectors can be different. For example, the maximum drift error is 12.2 nm, and the wavelengths used by the laser can be 850 nm, 870nm, 905nm, 940nm. This specification does not set the specific value of the wavelength spacing.
  • some of the lasers in the transmitting module can emit laser beams of the same wavelength.
  • the lasers in the transmitting module can be grouped.
  • the laser group includes at least one laser.
  • the emission wavelengths of the laser groups are different, the emission wavelengths of the lasers in the same laser group are the same, and the lasers in the same laser group do not emit simultaneously.
  • the lasers in each laser group can use a round-robin method to activate and output laser beams in sequence.
  • the number of lines of the lidar corresponds to the number of lasers.
  • an N-line lidar corresponds to N lasers and N corresponding detectors.
  • the lidar can be started in stages.
  • the laser emits light to realize N-line point cloud data acquisition in one acquisition frame, wherein the way the lidar starts the laser in stages is determined by the acquisition parameters of the lidar, and N is a positive integer; the number of laser groups is based on the lidar.
  • the maximum number of harnesses for a single simultaneous launch is determined.
  • the lidar can be a multi-line mechanical radar.
  • the horizontal angular resolution of the lidar is 0.2°
  • the range is 200m
  • the round-trip flight time of the light is 1.34 ⁇ s
  • the speed of the lidar is 10Hz
  • the time required for the lidar to rotate 0.2° is 55.6 ⁇ s, that is, each acquisition frame
  • the acquisition time interval between them is 55.6 ⁇ s.
  • the way to start the lasers in stages can be as follows: in one acquisition frame, the laser beam is emitted 32 times, and two lasers are activated each time to emit the laser beam. That is, the maximum number of beams emitted by the lidar at a single time is 2, and the lasers can be divided into two groups to meet the current number of lidar lines.
  • the way to start the lasers in stages can be: 40 times of laser beam emission in one acquisition frame, and one laser is activated for laser beam emission each time; or, 32 times in one acquisition frame 8 times for laser beam emission, of which 8 times for activating two lasers for laser beam emission, and 24 times for activating a single laser for laser beam emission. That is, the maximum number of beams emitted by the lidar at a single time is 2, and the lasers can be divided into two groups to meet the current number of lidar lines.
  • the laser beam output is performed 32 times in one acquisition frame, and four lasers are activated each time for laser beam emission. That is, the maximum number of beams emitted by the lidar at a single time is 4, and the lasers can be divided into four groups to meet the current number of lidar lines.
  • the arrangement of the lasers may include: 1) arranging in a linear array and 2) arranging in a matrix.
  • FIG. 3 and FIGS. 6a-6b it is a schematic diagram of a kind of lasers arranged in a linear array.
  • M laser groups may be included, that is, the laser groups 31-3M.
  • the lasers in each laser group All are arranged in a linear array.
  • multiple laser groups are arranged in a linear array.
  • the transmitting module 40 may include 2P laser groups, that is, laser groups 411 to 41P and laser groups 421 to 42P.
  • the lasers are arranged in a rectangular array.
  • multiple laser groups are arranged in a rectangular array.
  • the transmitting module 50 may include two laser groups, ie, laser groups 51 to 52 . Lasers in different laser groups are staggered in a rectangular array.
  • the photon detection probability (PDE) of the Si-based detector for the common wavelength range of lidar decreases with the wavelength. . That is, for the laser light in the wavelength range from 850 nm to 1550 nm, the longer the laser wavelength is, the lower the detection probability of the Si-based detector for the laser light of that wavelength is. Therefore, according to the actual application scenario of the lidar and the external environment corresponding to each laser, a specified position is selected in the lidar, and the wavelength corresponding to each laser group is positively correlated with the distance between the laser group and the specified position.
  • the designated position may be located in a plane perpendicular to the central axis of the lidar.
  • the lidar can be mounted on a mobile platform (such as an unmanned vehicle, etc.), the mobile platform is driving on the road, and the horizontal axis of the lidar is similar to the height of the mobile platform.
  • the detector with the emission angle closer to the horizontal central axis can collect more important point cloud data than other detectors with the emission angle farther from the horizontal central axis.
  • a specified position is selected in the vertical plane of the horizontal central axis.
  • the corresponding wavelength of each detector group becomes longer in turn, that is, the emitting unit with longer wavelength is used, so that it is located in the horizontal central axis.
  • Nearby detectors can obtain a higher detection probability, thereby increasing the amount of signals received and processed by the detectors and achieving better detection results.
  • the signal of the reflected laser beam is not strong (such as the low reflectivity of the target, the long distance between the target and the lidar, etc., the signal of the reflected laser beam is not strong), increase the detection.
  • the amount of point cloud data that can be collected by the device.
  • other types of detectors may be selected for photoelectric conversion, and the corresponding relationship between PDE and laser wavelength may be different from that of Si-based detectors. Therefore, in a plane perpendicular to the central axis of the lidar, a specified position is selected, and the laser wavelength emitted by the laser group closest to the specified position corresponds to the highest PDE of the detector, so that the detectors located near the horizontal central axis can obtain higher The detection probability is increased, and the amount of signals received and processed by the detector is increased to achieve a better detection effect.
  • the transmitting module 60 includes six laser groups 61-66, and the designated position is S. According to the distance between each laser group and the designated position, it can be determined that the laser group 64 sets the shortest Wavelength, for example, the laser group 64 can output a laser beam with a wavelength of 850 nm.
  • the laser group 61 can output a laser beam with a wavelength of 925nm
  • the laser group 62 can output a laser beam with a wavelength of 895nm
  • the laser group 63 can output a laser beam with a wavelength of 865 nm
  • the laser group 65 can output a laser beam with a wavelength of 880 nm
  • the laser group 66 can output a laser beam with a wavelength of 910 nm.
  • each laser group in Fig. 6 is arranged in a staggered manner.
  • the lasers can be arranged in a linear array (not shown), thereby narrowing the vertical spacing between the laser groups and making the number of lines more dense.
  • each laser mounting board is provided with non-emitting areas on the upper and lower edges of the laser lines. If, as shown in FIG. 6a, multiple laser chips are arranged on the same straight line in the vertical direction, it is difficult to achieve the highest luminous density in the vertical direction. Therefore, in this embodiment, as shown in Fig.
  • each laser group is staggered one by one, and the non-light-emitting area of the laser mounting board overlaps the light-emitting area of another laser mounting board in the horizontal direction, thereby improving the vertical direction.
  • the density of the light-emitting area on the lidar is beneficial to increase the vertical angular resolution of the lidar.
  • multiple lasers on the same mounting board can be mounted at different vertical angles to increase the vertical field of view of the lidar.
  • the light-emitting direction of the laser is not limited in the present invention.
  • a laser or laser group is provided on the laser mounting board 71 to form a light-emitting area 711 and a non-light-emitting area 712 that does not include lasers, and is also provided on the adjacent laser mounting board 72
  • different laser groups can output laser beams with different wavelengths in at least one of the following manners.
  • the lasers 111, 113-11n are the same laser group, and the laser 112 is another laser group.
  • the lasers 111, 113-11n are the first laser group
  • the laser 112 is the second laser group.
  • the first laser group ie, the lasers 111 , 113 to 11n
  • a light-emitting unit that emits a laser beam with a wavelength of ⁇ 1 is provided, and a light-emitting unit that emits a laser beam with a wavelength of ⁇ 2 is provided in the second laser group (ie, the laser 112 ).
  • the lasers 111 to 11n are respectively different laser groups.
  • the laser 111 is the first laser group
  • the laser 112 is the second laser group
  • the laser 11n is the second laser group.
  • the first laser group ie, the laser 111
  • a light-emitting unit that emits a laser beam with a wavelength of ⁇ 1 is provided in the second laser group (ie, the laser 112 ).
  • the nth laser group That is, the laser 11n
  • the laser 11n is provided with a light-emitting unit that emits a laser beam with a wavelength of ⁇ n.
  • the wavelengths of the laser beams emitted by the light-emitting units of each laser may be the same, that is, the wavelengths of the laser beams emitted by the light-emitting units of the multiple lasers that are simultaneously emitted are the same.
  • one laser group can correspond to one wavelength converter; if the laser group is arranged in a linear array In order to avoid confusing the laser beams, one laser corresponds to one wavelength converter.
  • the laser radar receiving part is described below.
  • the wavelength of the echo beam received by the detector matches the wavelength of the corresponding laser
  • the wavelength spacing of the laser is greater than the wavelength shift error of the laser as a function of temperature
  • the laser obtained by the corresponding detector The wavelength spacing between the beams is larger than the wavelength shift error of the laser with temperature.
  • the receiving module may include a filter, and the filter transmits a laser beam matching the wavelength of the corresponding laser in the incident light.
  • the detector includes one or more detection units, which are adapted to perform photoelectric signal conversion on the laser beam transmitted by the filter.
  • the receiving module 80 may include a filter 81 and a detector 82 disposed on the substrate 83 .
  • the filter 81 makes the incident light 8A A laser beam with a wavelength matching the corresponding laser is transmitted through, for example, a laser beam with a wavelength of ⁇ in FIG.
  • the detector 82 performs photoelectric signal conversion on the laser beam with a wavelength of ⁇ , thereby obtaining a corresponding electrical signal for subsequent data processing.
  • the receiving module may include a diaphragm, the diaphragm is arranged on the receiving focal plane, and each detector is arranged behind the diaphragm along the downstream of the optical path.
  • the incident light can be transmitted through the laser beam whose wavelength is matched with the corresponding laser, thereby reducing noise and improving the signal-to-noise ratio.
  • the wavelength output by the emission module has the characteristics of temperature drift, that is, the higher the temperature, the longer the actual output wavelength of the emission module; the lower the temperature, the longer the actual output wavelength of the emission module. shorter.
  • the filter band of the filter is narrow, the wavelength of the temperature-shifted laser beam exceeds the acceptable band-pass range and is filtered out by the filter as an interference signal, thereby reducing the efficiency of laser point cloud data collection.
  • the filter bandwidth of the filter can be set according to the wavelength of the corresponding laser and the offset error of the wavelength with temperature. This ensures that after the wavelength of the laser output shifts with temperature, the receiving channel can still transparently transmit the laser beam corresponding to the wavelength shift of the laser.
  • the wavelength shift error with temperature is 12.2nm
  • the wavelength of the laser is 850nm
  • the center wavelength of the filter is 850nm
  • the filter bandwidth of the filter is 15nm.
  • the wavelength of the laser beam that can pass through the filter is The range is: [850-7.5, 850+7.5] nm
  • the filter can still transmit the laser beam shifted by the corresponding laser in the incident light to the detection device.
  • the wavelength difference of the plurality of lasers and the bandwidth of the filter in the receiving module of the lidar satisfy the following relationship:
  • ⁇ 1 and ⁇ 2 are the first wavelength and the second wavelength of the laser, respectively, ⁇ 0 is the filter bandwidth of the filter, and ⁇ is the spectral width of the laser.
  • the detector may include one or more detection units, and the detection units may be at least one of the following types: 1) a single photon avalanche photodiode (SPAD); 2) an avalanche photodiode ( Avalanche Photo Diode, APD).
  • a single photon avalanche photodiode SPAD
  • avalanche photodiode Avalanche Photo Diode, APD
  • a laser can contain a SPAD array formed by multiple SPADs, and photoelectric conversion is performed by activating multiple SPADs in the SPAD array at the same time; an APD.
  • the detection devices of the plurality of detectors may be arranged in a regular arrangement, or may be arranged in an irregular arrangement, for example, the plurality of detection devices are arranged in a linear array or in a matrix array, Thereby, an array of detection devices is obtained; for another example, a plurality of detection devices are arranged in an irregular arrangement with dense distances in the middle and sparse ends at both ends in the vertical direction.
  • the plurality of detection devices may be arranged at fixed intervals or may be arranged at non-fixed intervals. This manual does not set the arrangement of multiple detection devices.
  • the light-emitting units in the lasers and the detection units in the detectors that have a corresponding relationship are arranged in the same manner.
  • the relative position of the light source in the laser is consistent with the relative position of the detection device in the detector, and the light source and the detection device can be one-to-one or one-to-many. The embodiments of the present specification do not limit this.
  • some lasers in the transmitting module can emit laser beams of the same wavelength, and correspondingly, some detectors in the receiving module have the same wavelength. In order to facilitate the management of the detectors, avoid activating the corresponding wavelengths.
  • Detectors of the same wavelength can receive simultaneously, and the detectors in the receiving module can be grouped.
  • the receiving module can include multiple detector groups, and the detector groups can include at least one detector. The detector groups respectively obtain laser beams matching the wavelengths of the corresponding lasers from the incident light, and the detectors in the detector groups do not receive them simultaneously.
  • the detectors in each detector group can use a round-robin method to activate and receive laser beams in sequence.
  • the number of the detector groups is determined based on the maximum number of beams emitted by the lidar at a single time, and the method of determining the maximum number of beams emitted by the lidar at a single time can refer to the relevant content in the transmitting section. This will not be repeated here.
  • the number of laser groups is also determined based on the highest number of beams emitted by the lidar at a single time, the number of laser groups is the same as the number of detector groups.
  • the arrangement of the detectors in the same detector group may include: 1) Arrangement in a linear array. For details, reference may be made to FIG. 3 and FIGS. 6 a to 6 b , which will not be repeated here. 2) Arranged in a rectangular array. For details, reference may be made to FIG. 4 and FIG. 5 , which will not be repeated here.
  • the laser radar 90 includes the transmitting module 91 of any of the above-mentioned laser radars and the receiving module 92 of any of the above-mentioned laser radars , and a controller 93, wherein: the controller 93 can control one or more lasers in the transmitting module 91 to emit, and control one or more detectors corresponding to the receiving module 92 to receive.
  • the controller 93 can control one or more lasers in the transmitting module 91 to emit, and control one or more detectors corresponding to the receiving module 92 to receive.
  • the relative arrangement position of the lasers in the transmitting module 91 is consistent with the relative arrangement position of the corresponding detector in the receiving module 92 .
  • This specification also provides a control method corresponding to the above-mentioned lidar, which will be described in detail below with reference to the accompanying drawings through specific embodiments. It should be known that the content of the control method described below can be referred to in correspondence with the content of the lidar described above.
  • the control method of the transmitting module can be applied to any of the above-mentioned lidars.
  • all The detection method of the lidar may include: A1) based on the wavelength and position information corresponding to each of the lasers, according to a preset emission control sequence, controlling the laser to emit light, so as to ensure that the simultaneously emitted lasers can emit laser beams of different wavelengths; A2 ) controls each detector in the receiving module to receive incident light matching the wavelength of the corresponding laser.
  • step A1) may further include step A11) and step A12).
  • the location information may include: address information of each laser connected to the controller on the lidar hardware, and the address information may be represented by pins connected between the laser and the controller.
  • an emission control command is generated and output to the emission module, so as to control the wavelengths of the laser beams emitted by the multiple lasers emitted at the same time to be different .
  • the transmitter module and the receiver module can perform light alignment operations to determine the channel emission control sequence of the laser and ensure that the correct laser is activated at the corresponding moment.
  • step A2) may further include step A21) and step A22).
  • the transmitter module and the receiver module can perform light alignment operations to determine the corresponding relationship between the laser and the detector.
  • the address information of each detector connected to the controller on the lidar hardware can be determined, and the address information can be represented by the pins connected between the detector and the controller.
  • a receiving control command is generated and output to the receiving module to control the receiving module to receive incident light at the same time, and obtain and correspond to the incident light from the incident light
  • the wavelength of the laser matches the laser beam.
  • the emission control instruction can control the activation of one or more lasers in the emission module.
  • the emission control instruction ensures that the wavelengths of the laser beams emitted by the multiple lasers emitted at the same time are different.
  • corresponding detectors can be activated for simultaneous reception by receiving control instructions, and the activated detectors can obtain laser beams matching the wavelengths of the corresponding lasers from the incident light.
  • the incident light received by the detector can contain echo beams of different wavelengths, and by matching the wavelengths, the laser beams corresponding to the lasers can be obtained from the incident light,
  • crosstalk between simultaneously activated detectors can be avoided, and the interference noise caused by external ambient light can be reduced, thereby improving the anti-interference ability between multiple detectors, effectively ensuring the signal receiving performance of the lidar, and reducing processing.
  • the need for jamming signals thereby reducing the difficulty of hardware design and software control of lidar.
  • the lasers in the emission module may be grouped, and thus, the step A12) may include steps A121) and A122).
  • A122 According to the identification information of the laser, select a laser, or select a laser from two or more of the laser groups respectively, and output the emission control instruction to control the selected laser to output a laser beam.
  • the arrangement of the lasers in the same laser group may include: 1) arranging in a linear array; 2) arranging in a rectangular array.
  • the arrangement of the detectors in the same detector group may include: 1) arrangement in a linear array; 2) arrangement in a rectangular array.
  • Embodiments of this specification also provide a lidar, which may include a memory and a controller, wherein the memory is adapted to store one or more computer-executable instructions; the controller is adapted to call one or more computer-executable instructions in the memory instructions to perform the steps of any of the above methods.
  • the lidar may further include a communication interface, and the lidar may be communicatively connected with other devices through the communication interface.
  • the other devices may include: a server, a terminal, a display device, and the like.

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Abstract

激光雷达（10）及其发射模组（11）、接收模组（12）、探测方法，激光雷达（10）的发射模组（11）包括：多个激光器（111~11n），激光器（111~11n）的发光波长包括第一波长和第二波长，适于同时发光的激光器（111~11n）具备不同的发光波长；激光雷达（10）的接收模组（12）包括：多个探测器（121~12m），每个探测器（121~12m）适于接收发射模组（11）中对应的激光器（111~11n）发出的激光光束被目标物（1x）反射的回波光束。能够提高多个探测器（121~12m）之间的抗干扰能力，有效保障激光雷达（10）的信号接收性能。

Description

激光雷达及其发射模组、接收模组、探测方法 技术领域
本说明书实施例涉及激光雷达技术领域，尤其涉及一种发射模组、接收模组、相关控制方法、激光雷达。
 背景技术
在激光雷达中，通过发射模组射出激光光束（即探测光束），并通过接收模组接收经过目标物反射回来的激光光束（即回波光束），接收模组将回波光束的光信号转换为电信号后，经过信号处理可以得到三维点云数据。
其中，发射模组中的各激光器处于发射焦平面的不同位置，接收模组中的各探测器相应处于接收焦平面的不同位置，因此，激光器可以向外界发射不同角度的光束，探测器可以接收外界不同角度反射回来的光束，从而在实现不同角度的空间测量。
目前，在一些场景中，发射模组需要激活多个激光器，对应地，接收模组需要激活多个探测器，基于激活的探测器的分布位置，可以分别接收对应激光器的回波光束。然而，激光雷达发射模组中各激光器发出的激光波长都是相同的，同时激活的多个探测器之间可能存在串扰，使得一个探测器中的探测单元还可能接收到其他同时激活的通道带来的波长相同的干扰噪声，造成测距误差。
 技术问题
因此，如何解决多个探测器之间存在的串扰成为了本领域技术人员亟待解决的问题。
 技术解决方案
有鉴于此，本说明书实施例提供一种发射模组、接收模组、探测方法、激光雷达，能够提高多个探测器之间的抗干扰能力，有效保障激光雷达的信号接收性能。
本说明书实施例提供一种激光雷达的发射模组，包括：多个激光器，所述激光器的发光波长包括第一波长和第二波长，适于同时发光的激光器具备不同的发光波长。
可选地，波长相同的多个激光器构成一个激光器组，所述激光器组的数量基于所述激光雷达同时发射的最高线束数量确定。
可选地，同一激光器组中的激光器不同时发射。
可选地，所述激光器包括一个或多个发光单元，适于发出激光光束，同时发射的多个激光器的波长不同。
可选地，所述激光器包括：一个或多个发光单元和波长转换器，其中：所述波长转换器，适于将所述发光单元发射的激光光束的波长转换至对应激光器所需的波长。
可选地，多个激光器的排列方式包括：按照线性阵列排布；按照矩形阵列排布。
可选地，各激光器的波长与所述激光器和指定位置之间的距离正相关，所述指定位置位于与所述激光雷达的水平中轴线垂直的平面。
可选地，靠近所述指定位置的激光器的波长，低于相对远离所述指定位置的激光器的波长。
可选地，所述多个激光器的波长差与所述激光器的波长随温度偏移误差满足如下关系：|λ1-λ2|≥α·ΔT+Δλ。
式中，λ1和λ2分别为所述激光器的第一波长和第二波长，α为所述激光器的温度漂移系数，ΔT为激光器工作过程最大温差，Δλ为激光器的光谱宽度。
可选地，所述多个激光器的波长差与所述激光雷达的接收模组中滤波器的带宽满足如下关系：|λ1-λ2|≥λ 0±Δλ。
式中，λ1和λ2分别为所述激光器的第一波长和第二波长，λ 0为所述滤波器的滤波带宽，Δλ为所述激光器的光谱宽度。
本说明书实施例还提供一种激光雷达的接收模组，包括：多个探测器，每个探测器适于上述发射模组中对应的激光器发出的激光光束被目标物反射的回波光束。
可选地，所述接收模组还包括滤波器，所述滤波器使所述入射光中与对应激光器的波长相同的激光光束透过。
可选地，所述滤波器的滤波带宽根据对应的激光器的波长和所述波长最大漂移误差设置。
可选地，所述探测器的排列方式包括：按照线性阵列排布；按照矩形阵列排布。
本说明书实施例还提供一种激光雷达，包括上述激光雷达的发射模组、上述激光雷达的接收模组、以及控制器，其中：所述控制器，适于控制所述激光器中的一个或多个发射激光光束，并控制所述探测器对应的一个或多个接收所述激光光束被目标物反射的回波光束。
可选地，所述激光器在所述发射模组的相对排布位置与对应探测器在所述接收模组的相对排布位置一致。
本说明书实施例还提供一种激光雷达的探测方法，应用于上述激光雷达，所述探测方法包括：A1）基于各所述激光器对应的波长及位置信息，按照预设的发射控制时序，控制激光器发光，以确保同时发射的激光器能发出不同波长的激光光束；A2）控制所述接收模组中每个探测器接收与对应激光器的波长匹配的入射光。
本说明书实施例还提供一种激光雷达，包括：存储器，适于存储一条或多条计算机可执行指令；控制器，适于调用所述存储器中的一条或多条计算机可执行指令，以执行上述探测方法步骤。
 有益效果
采用本说明书实施例的激光雷达方案，激光雷达中的发射模组可以包括多个激光器，激光器发光波长包括第一波长和第二波长，其中，发出第一波长的激光束的激光器为第一激光器，发出第二波长的激光束的激光器为第二激光器，第一激光器和第二激光器适于同时地发光，使得同时发光的激光器能够发出不同波长的激光光束；激光雷达中的接收模组可以包括多个探测器，其中探测器可接收对应激光器发光波长的入射光。由上述方案可知，通过同时发射的激光器发出不同波长的激光光束，可以使探测器仅接收与对应激光器发光波长相匹配的回波光束，通过匹配波长，能够避免接收其他激光器发出的光束造成的回波，从而避免同时激活的探测器之间的串扰，并能够降低外界环境光带来的干扰噪声，从而提高多个探测器之间的抗干扰能力，有效保障激光雷达的信号接收性能。
 附图说明
为了更清楚地说明本说明书实施例的技术方案，下面将对本说明书实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本说明书的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是本说明书实施例中一种激光雷达的发射接收模组的结构示意图。
图2是本说明书实施例中另一种激光雷达的发射接收模组的结构示意图。
图3是本说明书实施例中一种激光器按照线性阵列排布的示意图。
图4是本说明书实施例中一种激光器按照矩形阵列排布的示意图。
图5是本说明书实施例中一种激光器按照交错排列方式排布的示意图。
图6a是本说明书实施例中一种激光器组的波长设定方式示意图。
图6b是图6a中激光器组按照交错排列方式排布的示意图。
图7是本说明书实施例中一种激光器安装板按照交错排列方式排布的示意图。
图8是本说明书实施例中一种接收模组的结构示意图。
图9是本说明书实施例中一种激光雷达的结构示意图。
图10是本说明书实施例中一种激光雷达的发射模组控制方法的流程图。
图11是本说明书实施例中一种激光雷达的接收模组控制方法的流程图。
 本发明的实施方式
在激光雷达中，通过发射模组射出激光光束，并通过接收模组接收经过目标物反射回来的激光光束（即回波光束），接收模组将回波光束的光信号转换为电信号后，经过信号处理可以得到三维点云数据。
优选地，发射模组中的各激光器处于发射焦平面的不同位置，接收模组中的各探测器相应处于接收焦平面的不同位置，因此，激光器可以向外界发射不同角度的光束，探测器可以接收外界不同角度反射回来的光束，从而在实现不同角度的空间测量。
作为另一优选方案，可在接收焦平面设置光阑，滤除杂散光，沿光路下游在光阑后设置各探测器，以降低噪声，达到提高信噪比的目的。
目前，在一些场景中，发射模组需要同时激活多个激光器，用于同时发射多束激光光束，对应地，接收模组需要同时激活多个探测器，用于分别接收对应激光器发出的激光光束被目标物反射的回波光束。
然而，由于激光雷达中的接收光学组件是非理想性的，同时激活的多个探测器之间可能存在串扰，使得探测器还可能接收到其他探测器对应的回波光束，增加干扰噪声；甚至将其他探测器对应的回波光束误判为本探测器对应激光器的探测光束获得的目标物回波光束，造成鬼影等缺陷。
例如，激活激光器1和2同时发射激光光束，探测器1和2分别接收对应激光器1的回波光束（即激光器1射出的激光光束经过目标物反射后，返回激光雷达的激光光束）和对应激光器2的回波光束（即激光器2射出的激光光束经过目标物反射后，返回激光雷达的激光光束），在探测器1接收对应激光器1的回波光束时，另一个探测器2也能接收到少量对应激光器1的回波光束的杂散光。换而言之，可以将探测器1视为干扰源通道，探测器2视为被干扰通道，探测器2受到了探测器1的干扰影响，探测器1和探测器2之间存在串扰。
在实际应用中，干扰源通道接收的光信号强度越强，被干扰通道上的受到干扰的影响程度越大。例如，干扰源通道对应高反射率近距离的目标物反射回来的回波光束时，可能造成被干扰通道接收到来自干扰源的较强干扰噪声。一方面，强度较强的干扰噪声可能对同时激活的多个探测器造成干扰；另一方面，如果干扰噪声的强度足够强，以至于超过了被干扰通道的回波检测阈值，则会引起“假点”，多个假点组合起来会形成鬼影。
并且，由于激光器射出的激光光束的波长相同，被干扰通道实际需要获取的回波光束和干扰源通道的杂散光的波长相同，当二者叠加在一起时，探测装置无法从中区分出所要获取的回波信息，进而导致飞行时间的判定出现误差，引起测量精度下降。
由上可知，探测器之间存在串扰的情况将会对激光雷达的工作性能产生不良影响。因此，如何解决多个探测器之间的干扰成为了本领域技术人员亟待解决的问题。
针对上述问题，本说明书实施例提供了一种激光雷达的收发方案，激光雷达的发射模组包括多个激光器，且同时发射的激光器发出的激光光束的波长不相同；激光雷达的接收模组可以对应激活探测器接收入射光，且每个探测器只接收与对应激光器的波长匹配的激光光束。
由上述方案可知，通过同时发射的激光器发出不同波长的激光光束，可以使入射到探测器的杂散光与其对应激光器的回波光束波长不同，通过匹配波长，能够从入射到接收模组的光中滤除杂散光，只接收对应激光器的激光光束回波，从而避免同时激活的探测器之间的串扰，并能够降低外界环境光带来的干扰噪声，从而提高多个探测器之间的抗干扰能力，有效保障激光雷达的信号接收性能。
为使本领域技术人员更加清楚地了解及实施本发明的构思、实现方案及优点，以下参照附图，通过具体实施例进行详细说明。
在一个实施例中，参照图1所示的本说明书实施例中一种激光雷达的发射接收模组的结构示意图。在本说明书实施例中，如图1所示，所述激光雷达10可以包括：发射模组11和接收模组12。通过发射模组11和接收模组12可以分别进行激光发射和接收操作。
从发射模组11的角度进行描述，所述发射模组11可以包括：n个激光器111、112~11n和发射光学组件11a。
继续参照图1，发射模组11中设置有两种波长的激光器，其中，激光器111在激活时可以输出波长为λ1的激光光束11A，激光器112在激活时可以输出波长为λ2的激光光束11B，激光器113、114~11n在激活时可以输出波长为λ1的激光光束11A。
激活的激光器输出激光光束后，激光光束经过发射光学组件11a准直处理后，向外界发射出去，经过外界的目标物1x反射后，反射的回波光束射入接收模组12。
由于发射模组11中激光器发出的激光有两种波长λ1和λ2，因此，发射模组11存在两个激光器适于同时发射，可以同时激活两个输出不同波长的激光光束的激光器。
例如，在图1所示的实施例中，激光器111和112发光波长不同，则可以同时激活激光器111和112同时发射，使得激光器111发出波长为λ1的激光光束11A，且激光器112发出波长为λ2的激光光束11B。波长为λ1激光光束和波长为λ2的激光光束经过发射光学组件11a进行准直处理后，向外界发射出去，经过外界的目标物1x反射后，反射的波长为λ1的激光光束和波长为λ2的激光光束射入接收模组12。
以此类推，在本实施例中，激光器112与激光器111、113~11n均不相同，因此，可以同时激活激光器112和激光器111、113~11n中任意一个，从而使得同时发射的两个激光器发出不同波长的激光光束。
此外，接收模组12还可能接收外界的环境光和其他探测器对应波长的回波造成的杂散光，因此，接收模组12的入射光还可以包括：来自环境光的干扰噪声和来自其他探测器的干扰噪声。
从接收模组12的角度进行描述，所述接收模组12可以包括：m个探测器121~12m和接收光学组件12a，其中，探测器121~12m可以接收光学组件12a进行聚焦处理得到的入射光12A。激光器111~11n与探测器121~12m之间具有收发对应关系，即根据激活的激光器，可以确定对应激活的探测器。根据激光器与探测器的对应关系，对应激活探测器可以用于接收与激光器的波长匹配的激光光束。
例如，激光器111对应于探测器121，若激活激光器111，则对应激活探测器121用于接收与激光器111的波长λ1匹配的激光光束；激光器112对应于探测器122，若激活激光器112，则对应激活探测器122用于接收与激光器112的波长λ2匹配的激光光束。
在另一个实施例中，参照图2所示另一种激光雷达的发射接收模组的结构示意图。在本说明书实施例中，如图2所示，所述激光雷达20可以包括：发射模组21和接收模组22。通过发射模组21和接收模组22可以分别进行激光发射和接收操作。与图1相比，图2所示的激光雷达20的区别在于：包括多个不同的波长的激光器。
具体而言，激光器211在激活时可以输出波长为λ1的激光光束，激光器212在激活时可以输出波长为λ2的激光光束，激光器213在激活时可以输出波长为λ3的激光光束…激光器21n在激活时可以输出波长为λn的激光光束；λ1~λn均为不同的波长长度值，即λ1~λn互不相等。
由于发射模组21中设置有n种波长λ1~λn的激光器，因此，发射模组21最多存在n个激光器适于同时发射。当n个激光器211~21n中任意多个激光器激活时，同时发射的多个激光器能够发出不同波长的激光光束，由此，接收模组22接受到的入射光中包括对应的不同波长的激光光束。
例如，激活激光器211和212，则激光器211输出的激光光束21B的波长为λ1，激光器212输出的激光光束21A的波长为λ2，因此，在激活激光器211和212进行同时发射时，激光器211和212分别发出不同波长的激光光束。波长为λ1激光光束和波长为λ2的激光光束经过发射光学组件21a进行准直处理后，向外界发射出去，经过外界的目标物2x反射后，反射的波长为λ1的激光光束和波长为λ2的激光光束射入接收模组22。
又例如，激活激光器212~214，则激光器212输出的激光光束21B的波长为λ2，激光器213输出的激光光束21C的波长为λ3，激光器214输出的激光光束21D的波长为λ4，波长分别为λ2、λ3和λ4的激光光束经过发射光学组件215进行准直处理后，向外界发射出去，经过外界的目标物2x反射后，反射的波长分别为λ2、λ3和λ4的激光光束射入接收模组22。
此外，接收模组22还可能接收外界的环境光和其他探测器对应波长的回波造成的杂散光，因此，接收模组22的入射光还可以包括：来自环境光的干扰噪声和来自其他探测器的干扰噪声。
从接收模组22的角度进行描述，所述接收模组22可以包括：m个探测器221~22m和接收光学组件22a，其中，探测器221~22m可以接收光学组件22a进行聚焦处理得到的入射光22A。激光器211~21n与探测器221~22m之间具有对应关系，即根据激活的激光器，可以确定对应激活的探测器。根据激光器与探测器的对应关系，对应激活探测器可以用于接收与激光器的波长匹配的激光光束。
例如，激光器211对应于探测器221，若激活激光器211，则对应激活探测器221用于接收与激光器211的波长λ1匹配的激光光束；激光器212对应于探测器222，若激活激光器212，则对应激活探测器222用于接收与激光器212的波长λ2匹配的激光光束。
由图1和图2及相关描述内容可知，当n个激光器中至少两个激光器激活进行同时发射时，所述m个探测器中对应的至少两个探测器激活接收入射光。由于同时发射的多个激光器输出不同波长的激光光束，因此，所述入射光可以包括多个波长不同的激光光束，同时激活的多个探测器中每个探测器只接收与其对应激光器的波长匹配的激光光束，由此，通过波长匹配可以避免接收其他探测器对应激光器的杂散光。并且由于环境光通常为可见光，其波长通常与激光光束的波长不相同，因此，在设定探测器匹配的波长后，可以降低环境光对探测器的干扰。
作为一种优选示例，探测器个数与激光器的个数相同，即激光器与探测器一一对应，将与探测器所处同一收发通道的激光器所发出激光光束的波长，配置为该探测器所匹配的波长。
需要说明的是，上述示例仅为示意说明，在实际应用中，可以根据需求配置发射模组对应波长的种类数量，波长的种类数量可以与激光器的数量相同，也可以小于激光器的数量，换而言之，无需每个激光器的波长都不相同，可以存在部分波长相同的激光器，本说明书实施例对此不做限制。此外，还可以根据同时发射的激光器个数进行分组，具体可参考以下相关部分的描述，在此不再赘述。
可以理解的是，上述实施例仅为示例说明激活多个激光器和探测器的情况，在实际应用时，激光雷达可以根据实际应用场景和需求设定进行激光收发操作时激活的激光器和探测器的数量。并且，激光雷达激光器和探测器的数量，以及激光器和探测器对应的波长也可以根据实际应用场景和需求进行设定。本说明书实施例对此均不作具体限制。
还可以理解的是，本说明书实施例的附图仅为示例说明，根据实际应用场景，激光雷达还可以包括其他硬件模块、硬件电路等，例如，激光雷达还可以包括控制模块、扫描模块、以及各模块的适配电路等，其中，适配电路可以包括：信号读取电路和为各模块提供电源的电源供给电路等，本说明书对于激光雷达的具体结构不做限制。
继续参考图1可知，本说明书实施例提供的激光雷达包括发射部分和接收部分，为了便于本领域的技术人员理解和实施，以下先对激光雷达的发射部分进行描述。
在具体实施中，所述激光器包括一个或多个发光单元，适于发出激光光束。其中，所述发光单元包括以下至少一种类型：1）垂直腔面发射激光器（Vertical-Cavity Surface-Emitting Laser，VCSEL）；2）边缘发射激光器（Edge Emitting Laser ，EEL）。
根据实际需求，可以选择不同类型的发光单元，且激光器包含的发光单元的数量与发光功率需求以及发光单元的类型有关。例如，由于单个VCSEL发光率较低，为了符合发光需求，一个激光器中可以包含多个VCSEL形成的VCSEL阵列，通过同时激活VCSEL阵列中多个VCSEL进行发光，并通过发射光学组件整形为一束激光；又例如，单个EEL发光率较高，在单个EEL符合发光需求时，一个激光器中可以包含一个EEL。
在具体实施中，多个激光器可以按照规则的排列方式排布，也可以按照不规则的排列方式排布，例如，多个激光器按照线性阵列排布或者按照矩阵排布，从而得到激光器阵列；又例如，多个激光器在竖直方向按照中间距离密、两端疏的不规则排列方式排布。并且，多个激光器可以按照固定间距进行排列，也可以按照不固定间距进行排列。本说明书对于多个激光器的排布不做设定。
在实际应用中，激光器发出的激光光束的波长存在一定的分布范围，即激光器的光谱宽度（spectral width）。在波长分布范围中，将光能量最大的波长设为该激光器的中心波长，也即激光器的波长。例如，标注发出波长为1550nm（纳米）的激光光束的激光器，其实际发出的激光光束的波长分布范围可能为1549～1551nm，中心波长为1550nm。
在具体实施中，激光器实际输出的激光光束的中心波长会随着温度变化有所漂移，例如，温度上升，激光器实际输出的中心波长变长；温度下降，激光器实际输出的中心波长变短。由此，随着温度的变化，各激光器实际输出的激光光束的波长发生温度漂移，可能原本对应不同波长的激光器，在温度影响下输出的激光光束的波长相同，从而在同时发射的激光器中，可能存在温度漂移后输出相同波长的激光器。
为了避免温度偏移对激光器的影响，不同波长之间的波长间距可以大于所述发射模组随温度变化的波长最大漂移误差，从而确保激光器输出激光光束的波长存在温度漂移时，其漂移后的波长也与其他激光器输出的激光光束的波长不相同。
例如，VCSEL的温度漂移系数为0.07nm/C°，若在激光雷达工作过程中激光器的温度区间为[-40°C，+120°C]，则激光器随温度变化的波长最大漂移为11.2nm，将不同波长之间波长间距大于11.2nm，可以确保激光器输出激光光束的波长在漂移后也与其他激光器输出的激光光束的波长不相同。
进一步地，考虑到发光单元的光谱宽度，所述波长随温度偏移误差可以由一定温度区间下的波长温度漂移和光谱宽度决定。例如，VCSEL的温度漂移系数为0.07nm/C°，若温度区间为[-40°C，+120°C]，则激光器随温度变化的波长最大漂移为11.2nm，光谱宽度为1nm，则激光器随温度变化的波长偏移误差为12.2nm，将不同波长之间波长间距大于12.2nm，可以确保激光器输出激光光束的波长在漂移后也与其他激光器输出的激光光束的波长不相同。
可选的，所述波长间距与激光器波长随温度偏移误差满足如下关系：|λ1-λ2|≥α·ΔT+Δλ。
式中，λ1和λ2分别为所述激光器的第一波长和第二波长，α为激光器的温度漂移系数，ΔT为激光器工作过程最大温差，Δλ为激光器的光谱宽度。
为了便于设置各激光器的波长，波长间距可以取整数，如15nm、20nm、25nm等，根据波长间距可以选取对应波长的发光单元，例如，若激光器的波长间距为20nm，则各激光器采用的波长可以分别为850nm、870nm、890nm等。并且，各探测器之间的波长间距在满足大于波长最大漂移误差条件后，各探测器之间的波长间距可以不相同，例如，最大漂移误差为12.2nm，激光器采用的波长可以分别为850nm、870nm、905nm、940nm。本说明书对于波长间距的具体取值不做设定。
在具体实施中，所述发射模组中的部分激光器可以发出相同波长的激光光束，为了便于激光器的管理，避免波长相同的激光器激活进行同时发射，可以对发射模组中的激光器进行分组，各激光器组包括至少一个激光器。各所述激光器组的发光波长不同，同一激光器组中的激光器的发光波长相同，同一激光器组中的激光器不同时发射。
其中，各激光器组内的激光器可以采用轮巡的方式，依照次序激活并输出激光光束。
在具体实施中，所述激光雷达的线数与激光器的数量对应，如N线激光雷达对应N个激光器和N个相应的探测器，在激光雷达的一个采集帧中，激光雷达可以分次启动激光器进行发光，从而在一个采集帧中实现N线点云数据采集，其中，激光雷达分次启动激光器的方式由激光雷达的采集参数决定，N为正整数；激光器组的数量基于所述激光雷达单次同时发射的最高线束数量确定。此外，激光雷达可以为多线机械雷达。
例如，激光雷达的水平角分辨率为0.2°，测距200m，光的往返飞行时间为1.34μs，激光雷达的转速10Hz，则激光雷达转过0.2°的耗时为55.6μs，即各采集帧之间的采集时间间隔为55.6μs，在一个采集时间间隔内，激光雷达的发光最大次数为：55.6/1.34=41.5，也就是说，在一个采集时间间隔内，激光雷达最多能够进行41次激光光束发射。
对于64线的激光雷达而言，分次启动激光器的方式可以为：在一个采集帧中按32次进行激光光束发射，每次激活两个激光器进行激光光束发射。即激光雷达单次同时发射的最高线束数量为2，激光器分两组即可满足目前的激光雷达线数需求。
对于40线的激光雷达而言，分次启动激光器的方式可以为：在一个采集帧中按40次进行激光光束发射，每次激活一个激光器进行激光光束发射；或者，在一个采集帧中按32次进行激光光束发射，其中，8次激活两个激光器进行激光光束发射，24次激活单个激光器进行激光光束发射。即激光雷达单次同时发射的最高线束数量为2，激光器分两组即可满足目前的激光雷达线数需求。
对于128线的激光雷达而言，在一个采集帧中按32次进行激光光束输出，每次激活四个激光器进行激光光束发射。即激光雷达单次同时发射的最高线束数量为4，激光器分四组即可满足目前的激光雷达线数需求。
在具体实施中，激光器的排列方式可以包括：1）按照线性阵列排布和2）按照矩阵排布。
1）按照线性阵列排布。如图3和图6a-6b所示，为一种激光器按照线性阵列排布的示意图，在发射模组30中，可以包括M个激光器组，即激光器组31~3M，各激光器组中的激光器均按照线性阵列排布。同样的，多个激光器组按线性阵列排布。
2）按照矩阵排布。如图4所示，为一种激光器按照矩形阵列排布的示意图，在发射模组40中，可以包括2P个激光器组，即激光器组411~41P以及激光器组421~42P，各激光器组中的激光器按照矩形阵列排布。同样的，多个激光器组按矩形阵列排布。
如图5所示，为一种激光器按照交错排列方式排布的示意图，在发射模组50中，可以包括2个激光器组，即激光器组51~52。不同激光器组中的激光器按照矩形阵列交错排布。
可以理解的是，上述实施例仅为示例说明，在实际应用中，本说明书所述的激光器的排列方式可以结合具体情景，合理地进行交叉选用。
在具体实施中，在探测器采用常用的Si（硅）基探测器进行光电转换的情况下，Si基探测器对激光雷达常用波长范围的激光光子探测概率（Photon Detection Efficiency，PDE）随波长降低。即、对于从850nm至1550nm波长范围的激光，激光波长越长，Si基探测器对该波长激光的探测概率越低。因此，结合激光雷达实际应用场景，以及各激光器对应的外界环境，在激光雷达中选择一指定位置，各所述激光器组对应的波长与所述激光器组和指定位置之间的距离正相关。
可选地，所述指定位置可以位于与所述激光雷达中轴线垂直的平面。例如，激光雷达可装载于一移动平台上（如无人车等），移动平台在马路上行驶，激光雷达水平中轴线与移动平台的高度相近，在水平中轴线对应的视场中，存在较多物体的概率更大，因此，发射角度越靠近水平中轴线的探测器相对于其他发射角度远离水平中轴线的探测器，能够采集到更加重要的点云数据。
由此，在水平中轴线的垂直平面中选择一指定位置，从与指定位置最近的激光器组开始，各探测器组对应波长依次变长，即采用波长更长的发射单元，使得位于水平中轴线附近的探测器能够获得更高的探测概率，进而增大探测器所接收和处理的信号量，实现更好的探测效果。并且，在反射回来的激光光束的信号不强的情况下（如目标物的反射率较低，目标物与激光雷达的距离较远等原因导致反射回来的激光光束的信号不强），增加探测器能够采集到点云数据量。
在另一实施例中，可选择其他类型的探测器进行光电转换，其PDE与激光波长的对应关系可能与Si基探测器不同。因此，在与激光雷达中轴线垂直的平面，选择一指定位置，与指定位置距离最近的激光器组所发出的激光波长对应探测器最高的PDE，使得位于水平中轴线附近的探测器能够获得更高的探测概率，进而增大探测器所接收和处理的信号量，实现更好的探测效果。
在按照指定位置设定各探测器组的波长时，各探测器组之间对应的波长间距可以不相同，但是必须大于波长最大漂移误差。例如，如图6a所示，所述发射模组60中包括6 个激光器组61~66，指定位置为S，根据各激光器组和指定位置之间的距离，可以确定激光器组64设定最短的波长，如激光器组64可以输出波长为850nm的激光光束，若波长间距为15nm，则将850nm作为初始波长，按照激光器组的数量，依次增加15nm，得到其余5个激光器组的波长可以为：865nm、880nm、895nm、910nm和925nm，如图6a所示，按照其余各激光器组和指定位置之间的距离，激光器组61可以输出波长为925nm的激光光束，激光器组62可以输出波长为895nm的激光光束，激光器组63可以输出波长为865nm的激光光束，激光器组65可以输出波长为880nm的激光光束，激光器组66可以输出波长为910nm的激光光束。
在具体实施中，为了增加激光器在竖直方向上的排布紧密度，如图6b所示，与图6a相比，图6中各激光器组采用交错排列的方式进行排布，各激光器组中激光器可以以线形阵列排布（图未示），从而缩小竖直方向上各激光器组之间的间隔，使线数更加密集。
如图6b所示的实施例中，一个激光器组的多个波长相同的激光器设置在同一安装板（如印刷线路板，PBC）上，多个激光器组的激光器安装板在竖直方向上排列，每个激光器安装板上的多个激光器也在竖直方向排列成线列。为便于激光器封装，每个激光器安装板上在激光器线列的上下边缘均设有非发光区。若如图6a所示，多个激光器芯片在竖直方向排列在同一直线上，难以在竖直方向上达到最高的发光密度。因此，在本实施例中，如图6b所示，将各激光器组一一交错排布，激光器安装板的非发光区与另一激光器安装板的发光区在水平方向重叠，从而提高竖直方向上的发光区密度，有利于增大激光雷达的垂直角分辨率。
作为优选，同一安装板上的多个激光器可朝向不同竖直角度装配，以增大激光雷达的垂直视场角。激光器的发光方向本发明不做限定。
在一示例中，如图7所示，在激光器安装板71上设置有激光器或激光器组，从而形成发光区711和不包括激光器的非发光区712，在相邻的激光器安装板72上也设置有激光器或激光器组，从而形成包括激光器的发光区721和不包括激光器的非发光区722；激光器安装板71和72沿垂直于纸面方向发射激光光束，则将激光器安装板71上非发光区与激光器安装板72的非光区在平行于纸面的方向上进行重叠，从而在垂直于纸面的出光方向上，两个激光器安装板的发光区间距大大缩小。
在具体实施中，不同激光器组可以采用以下至少一种方式输出不同波长的激光光束。
1）通过设置发射不同波长的激光光束的激光器，确保进行同时发射的多个激光器中的发光单元发出的激光光束的波长不同。
例如，参考图1，激光器111、113~11n为同一激光器组，激光器112为另一激光器组，为了便于描述，以激光器111、113~11n为第一激光器组，激光器112为第二激光器组。在第一激光器组（即激光器111、113~11n）中设置发射λ1波长的激光光束的发光单元，在第二激光器组（即激光器112）中设置发射λ2波长的激光光束的发光单元。
又例如，参考图2，激光器111~11n分别为不同激光器组，为了便于描述，以激光器111为第一激光器组，激光器112为第二激光器组，以此类推，激光器11n为第二激光器组。第一激光器组（即激光器111）中设置发射λ1波长的激光光束的发光单元，在第二激光器组（即激光器112）中设置发射λ2波长的激光光束的发光单元……在第n激光器组（即激光器11n）中设置发射λn波长的激光光束的发光单元。
2）采用波长转换器，将各激光器中发光单元发射的激光光束的波长转换至对应激光器所需的波长，确保进行同时发射的多个激光器中的发光单元发出的激光光束的波长不同。
采用波长转换器的方案中，各激光器的发光单元发射的激光光束的波长可以相同，即同时发射的多个激光器中的发光单元发出的激光光束的波长相同。采用这样的方案，无需在一个激光雷达中装配多种不同波长的激光器，有利于降低生产成本。波长转换器与激光器的对应关系由激光器实际采用的排列方式，例如，若激光器组中各激光器按照线性阵列排布，则为了降低成本缩小空间，可以一个激光器组对应一个波长转换器；若激光器组中各激光器与其他激光器组中的激光器按照交错排列方式排布，则为了不混淆激光光束，一个激光器对应一个波长转换器。
结合上述激光雷达发射部分的描述，以下对激光雷达接收部分进行描述。
在具体实施中，由于探测器接收的回波光束的波长与对应激光器的波长匹配，因此，在激光器的波长间距大于所述激光器随温度变化的波长偏移误差时，对应的探测器获取的激光光束之间的波长间距大于激光器随温度变化的波长偏移误差。不同波长之间的波长间距的设置方式可以具体参照激光雷达发射部分的相关描述，在此不再赘述。
在具体实施中，所述接收模组可以包括滤波器，所述滤波器使所述入射光中与对应激光器的波长匹配的激光光束透过。此外，所述探测器包括一个或多个探测单元，适于对滤波器传递的激光光束进行光电信号转换。
在一示例中，如图8所示，接收模组80可以包括滤波器81和设置于基板83上的探测器82，入射光8A经过滤波器81时，滤波器81使所述入射光8A中与对应激光器的波长匹配的激光光束透过，如图8中波长为λ的激光光束透过滤波器81，射入探测器82。探测器82对波长为λ的激光光束进行光电信号转换，从而得到相应的电信号，用于后续的数据处理。
可选地，接收模组中可以包括光阑，光阑设置于接收焦平面，沿光路下游在光阑后设置各探测器，光阑可以过滤入射光中不符合指定方向的光束，滤波器则可以使所述入射光与对应激光器的波长匹配的激光光束透过，从而能够降低噪声，提高信噪比。
在具体实施中，由发射部分相关内容可知，发射模组输出的波长具有温度漂移的特性，即温度越高，发射模组实际输出的波长越长；温度越低，发射模组实际输出的波长越短。若滤波器的滤波带通过窄，则温度偏移后的激光光束的波长超出可以带通范围，被滤波器当作干扰信号滤除，从而降低激光点云数据采集效率。为了避免温度偏移对探测器的影响，所述滤波器的滤波带宽可以根据对应的激光器的波长和所述波长随温度偏移误差设置。由此确保激光器输出的波长随温度发生偏移后，接受通道仍然可以透传对应激光器波长偏移后的激光光束。
例如，波长随温度偏移误差为12.2nm，激光器的波长为850nm，则滤波器的中心波长为850nm，滤波器的滤波带宽为15nm，换而言之，能够透过滤波器的激光光束的波长范围为：[850-7.5，850+7.5] nm，若激光器输出的激光光束的波长的偏移范围在[850-7.5，850+7.5] 区间内，则滤波器仍然可以将入射光中对应激光器偏移后的激光光束透传至探测装置。
在一实施例中，多个激光器的波长差与所述激光雷达的接收模组中滤波器的带宽满足如下关系：|λ1-λ2|≥λ 0±Δλ。
式中，λ1和λ2分别为所述激光器的第一波长和第二波长，λ 0为滤波器的滤波带宽，Δλ为激光器的光谱宽度。
在具体实施中，所述探测器可以包括一个或多个探测单元，探测单元可以为以下至少一种类型：1）单光子雪崩光电二极管（Single Photon Avalanche Diode，SPAD）；2）雪崩光电二极管（Avalanche Photo Diode，APD）。
根据实际需求，可以选择不同类型的探测单元，且激光器包含的探测单元的数量与探测单元的类型有关。例如，由于单个SPAD体积较小，一个激光器中可以包含多个SPAD形成的SPAD阵列，通过同时激活SPAD阵列中多个SPAD进行光电转换；又例如，单个APD光敏面较大，一个激光器中可以包含一个APD。
在具体实施中，多个探测器的探测装置可以按照规则的排列方式排布，也可以按照不规则的排列方式排布，例如，多个探测装置按照线性阵列排布或者按照矩阵阵列排布，从而得到探测装置阵列；又例如，多个探测装置按照竖直方向中间距离密、两端疏的不规则排列方式排布。并且，多个探测装置可以按照固定间距进行排列，也可以按照不固定间距进行排列。本说明书对于多个探测装置的排布不做设定。
可选地，存在对应关系的激光器中的发光单元与探测器中的探测单元采用相同的排列方式。并且，光源在激光器中的相对位置与探测装置在探测器中的相对位置一致，光源和探测装置可以一对一，也可以一对多。本说明书实施例对此不做限制。
在具体实施中，所述发射模组中的部分激光器可以发射相同波长的激光光束，相应地，所述接收模组中的部分探测器对应的波长相同，为了便于探测器的管理，避免激活对应相同波长的探测器进行同时接收，可以对接收模组中的探测器进行分组，所述接收模组可以包括多个探测器组，所述探测器组可以包括至少一个探测器，各所述探测器组分别从所述入射光中获取与对应激光器的波长匹配的激光光束，所述探测器组中的探测器不同时接收。
其中，各探测器组内的探测器可以采用轮巡的方式，依照次序激活并接收激光光束。
在具体实施中，所述探测器组的数量基于所述激光雷达单次同时发射的最高线束数量确定，其中，确定激光雷达单次同时发射的最高线束数量的方式可参考发射部分相关内容，在此不再赘述。并且，由于激光器组的数量也是基于所述激光雷达单次同时发射的最高线束数量确定，因此，激光器组的数量与探测器组的数量相同。
在具体实施中，同一探测器组中的探测器的排列方式可以包括：1）按照线性阵列排布。具体可参考图3和图6a~6b，在此不再赘述。2）按照矩形阵列排布。具体可参考图4和图5，在此不再赘述。
可以理解的是，上述实施例仅为示例说明，在实际应用中，本说明书所述的探测器的排列方式可以结合具体情景，合理地进行交叉选用。
在具体实施中，如图9所示，为一种激光雷达的结构示意图，在激光雷达90中，包括上述任一种激光雷达的发射模组91、上述任一种激光雷达的接收模组92、以及控制器93，其中：所述控制器93可以控制所述发射模组91中的一个或多个激光器发射，并控制所述接收模组92对应的一个或多个探测器接收。激光雷达的发射模组和接收模组的内容可参考上述相关部分的描述，在此不再赘述。
其中，所述激光器在所述发射模组91的相对排布位置与对应探测器在所述接收模组92的相对排布位置一致。
可以理解的是，上文描述了本说明书提供的多个实施例方案，各实施例方案介绍的各可选方式可在不冲突的情况下相互结合、交叉引用，从而延伸出多种可能的实施例方案，这些均可认为是本说明书披露、公开的实施例方案。
本说明书还提供了与上述激光雷达对应的控制方法，以下参照附图，通过具体实施例进行详细介绍。需要知道的是，下文描述的控制方法的内容，可与上文描述的激光雷达的内容相互对应参照。
参照图10所示的本说明书实施例中一种激光雷达的探测方法的流程图，所述发射模组控制方法可应用于上述任一种所述的激光雷达，在本说明书实施例中，所述激光雷达的探测方法可以包括：A1）基于各所述激光器对应的波长及位置信息，按照预设的发射控制时序，控制激光器发光，以确保同时发射的激光器可发出不同波长的激光光束；A2）控制所述接收模组中每个探测器接收与对应激光器的波长匹配的入射光。
具体的，步骤A1）可进一步包括步骤A11）和步骤A12）。
A11）获取所述发射模组中各激光器对应的波长及位置信息。
其中，所述位置信息可以包括：各激光器在激光雷达硬件上与控制器连接的地址信息，所述地址信息可以通过激光器与控制器连接的管脚进行表征。
A12）基于各所述激光器对应的波长及位置信息，按照预设的通道发射控制时序，生成发射控制指令，输出至所述发射模组，以控制同时发射的多个激光器发出的激光光束波长不同。
在激光雷达装调过程中，发射模组与接收模组可以进行对光操作，从而确定激光器的通道发射控制时序，确保相应时刻激活正确的激光器。
相应地，参照图11所示，步骤A2）可进一步包括步骤A21）和步骤A22）。
A21）获取所述接收模组中各探测器与所述激光雷达的激光器的选址对应关系。
在激光雷达装调过程中，发射模组与接收模组可以进行对光操作，从而确定激光器与探测器的对应关系。并根据激光雷达的硬件结构，可以确定各探测器在激光雷达硬件上与控制器连接的地址信息，所述地址信息可以通过探测器与控制器连接的管脚进行表征。通过建立激光器与对应的探测器在地址信息上的关联，可以得到选址对应关系，便于后续生成接收控制指令。
A22）基于同时发射的激光器和所述选址对应关系，生成接收控制指令，输出至所述接收模组，以控制所述接收模组同时接收入射光，并从所述入射光中获取与对应激光器的波长匹配的激光光束。
在实际应用中，发射控制指令可以控制发射模组中的一个或多个激光器激活，在多个激光器进行同时发射时，发射控制指令确保同时发射的多个激光器发出的激光光束波长不同。在激活多个激光器时，相应地，通过接收控制指令可以激活对应的探测器进行同时接收，激活的探测器可以从所述入射光中获取与对应激光器的波长匹配的激光光束。
由上述方案可知，通过同时发射的激光器输出不同波长的激光光束，可以使探测器接收的入射光中包含不同波长的回波光束，通过匹配波长，能够从入射光中获取对应激光器的激光光束，从而避免同时激活的探测器之间的串扰，并能够降低外界环境光带来的干扰噪声，从而提高多个探测器之间的抗干扰能力，有效保障激光雷达的信号接收性能，并且可以减少处理干扰信号的需求，从而降低激光雷达的硬件设计难度和软件控制难度。
在具体实施中，为了便于激光器的管理，避免波长相同的激光器激活进行同时发射，可以对发射模组中的激光器进行分组，由此，所述步骤A12）可以包括步骤A121）和A122）。
A121）基于各所述激光器对应的波长，确定属于同一组的激光器，得到多个激光器组。
A122）根据激光器的标识信息，选取一个激光器，或从两个以上所述激光器组中分别选取一个激光器，输出所述发射控制指令，以控制所选择的激光器输出激光光束。
在具体实施中，由上述相关部分可知，同一激光器组中的激光器的排列方式可以包括：1）按照线性阵列排布；2）按照矩形阵列排布。
同样地，由上述相关部分可知，同一探测器组中的探测器的排列方式可以包括：1）按照线性阵列排布；2）按照矩形阵列排布。
可以理解的是，上文描述了本说明书提供的多个实施例方案，各实施例方案介绍的各可选方式可在不冲突的情况下相互结合、交叉引用，从而延伸出多种可能的实施例方案，这些均可认为是本说明书披露、公开的实施例方案。
本说明书实施例还提供一种激光雷达，可以包括存储器和控制器，其中，存储器适于存储一条或多条计算机可执行指令；控制器适于调用所述存储器中的一条或多条计算机可执行指令，以执行上述任一种方法的步骤。
在具体实施中，所述激光雷达还可以包括通信接口，通过通信接口所述激光雷达可以与其他装置进行通信连接。所述其他装置可以包括：服务器、终端、显示装置等。
虽然本说明书实施例披露如上，但本说明书实施例并非限定于此。任何本领域技术人员，在不脱离本说明书实施例的精神和范围内，均可作各种更动与修改，因此本说明书实施例的保护范围应当以权利要求所限定的范围为准。

Claims (18)

  1. 一种激光雷达的发射模组，其特征在于，包括：多个激光器，所述激光器的发光波长包括第一波长和第二波长，适于同时发光的激光器具备不同的发光波长。
  2. 根据权利要求1所述的激光雷达的发射模组，其特征在于，波长相同的多个激光器构成一个激光器组，所述激光器组的数量基于所述激光雷达同时发射的最高线束数量确定。
  3. 根据权利要求2所述的激光雷达的发射模组，其特征在于，同一激光器组中的激光器不同时发射。
  4. 根据权利要求1所述的激光雷达的发射模组，其特征在于，所述激光器包括一个或多个发光单元，适于发出激光光束，同时发射的多个激光器的波长不同。
  5. 根据权利要求1所述的激光雷达的发射模组，其特征在于，所述激光器包括：一个或多个发光单元和波长转换器，其中：
    所述波长转换器，适于将所述发光单元发射的激光光束的波长转换至对应激光器所需的波长。
  6. 根据权利要求1所述的激光雷达的发射模组，其特征在于，多个激光器的排列方式包括：
    按照线性阵列排布；
    按照矩形阵列排布。
  7. 根据权利要求1所述的激光雷达的发射模组，其特征在于，各激光器的波长与所述激光器和指定位置之间的距离正相关，所述指定位置位于与所述激光雷达的水平中轴线垂直的平面。
  8. 根据权利要求7所述的激光雷达的发射模组，其特征在于，靠近所述指定位置的激光器的波长，低于相对远离所述指定位置的激光器的波长。
  9. 根据权利要求1所述的激光雷达的发射模组，其特征在于，所述多个激光器的波长差与所述激光器的波长随温度偏移误差满足如下关系：
    |λ1-λ2|≥α·ΔT+Δλ，
    式中，λ1和λ2分别为所述激光器的第一波长和第二波长，α为所述激光器的温度漂移系数，ΔT为所述激光器工作过程最大温差，Δλ为所述激光器的光谱宽度。
  10. 根据权利要求1所述的激光雷达的发射模组，其特征在于，所述多个激光器的波长差与所述激光雷达的接收模组中滤波器的带宽满足如下关系：
    |λ1-λ2|≥λ 0±Δλ，
    式中，λ1和λ2分别为所述激光器的第一波长和第二波长，λ 0为所述滤波器的滤波带宽，Δλ为所述激光器的光谱宽度。
  11. 一种激光雷达的接收模组，其特征在于，包括：多个探测器，每个探测器适于接收权利要求1-10任一项所述的发射模组中对应的激光器发出的激光光束被目标物反射的回波光束。
  12. 根据权利要求11所述的激光雷达的接收模组，其特征在于，所述接收模组还包括滤波器，所述滤波器使入射光中与对应激光器的波长相同的激光光束透过。
  13. 根据权利要求12所述的激光雷达的接收模组，其特征在于，所述滤波器的滤波带宽根据对应的激光器的波长和波长最大漂移误差设置。
  14. 根据权利要求11所述的激光雷达的接收模组，其特征在于，所述探测器的排列方式包括：
    按照线性阵列排布；
    按照矩形阵列排布。
  15. 一种激光雷达，其特征在于，包括上述1-10任一项所述的激光雷达的发射模组、上述11-14任一项所述的激光雷达的接收模组、以及控制器，其中：
    所述控制器，适于控制激光器中的一个或多个发射激光光束，并控制探测器对应的一个或多个接收所述激光光束被目标物反射的回波光束。
  16. 根据权利要求15所述的激光雷达，其特征在于，所述激光器在所述发射模组的相对排布位置与对应探测器在所述接收模组的相对排布位置一致。
  17. 一种激光雷达的探测方法，其特征在于，应用于上述权利要求15-16任一项所述的激光雷达，所述探测方法包括：
    A1）基于各所述激光器对应的波长及位置信息，按照预设的发射控制时序，控制激光器发光，以确保同时发射的激光器能发出不同波长的激光光束；
    A2）控制所述接收模组中每个探测器接收与对应激光器的波长匹配的入射光。
  18. 一种激光雷达，其特征在于，包括：
    存储器，适于存储一条或多条计算机可执行指令；
    控制器，适于调用所述存储器中的一条或多条计算机可执行指令，以执行如权利要求17所述的方法步骤。
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