WO2023133963A1 - 激光雷达系统及其控制方法 - Google Patents

激光雷达系统及其控制方法 Download PDF

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WO2023133963A1
WO2023133963A1 PCT/CN2022/076479 CN2022076479W WO2023133963A1 WO 2023133963 A1 WO2023133963 A1 WO 2023133963A1 CN 2022076479 W CN2022076479 W CN 2022076479W WO 2023133963 A1 WO2023133963 A1 WO 2023133963A1
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time
photodetector
laser
units
unit
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PCT/CN2022/076479
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French (fr)
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常健忠
寿翔
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杭州宏景智驾科技有限公司
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    • 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
    • G01S7/495—Counter-measures or counter-counter-measures using electronic or electro-optical means
    • 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
    • G01S7/4802—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section

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  • the present disclosure relates to lidar technology, and in particular to an anti-jamming method and system for lidar.
  • Environmental light sources generally include three types: light sources with the same frequency as the lidar, light sources with different frequencies from the lidar, and light sources with random frequencies.
  • the lasers emitted by multiple identical lidars belong to the same frequency light source, and the light sources emitted by different lidars belong to different frequency light sources. light source.
  • the present disclosure improves the laser radar related technology and makes further improvements, so as to improve the convenience and accuracy of the laser radar system.
  • a control method for a laser radar system comprising:
  • each sequence time in the time sequence is the sum of the recurring cycle time and randomly generated random time, and is separated into multiple time units;
  • the random time of the first sequence time of said time series is replaced with zero.
  • the cycle time is greater than or equal to the cumulative duration of the preset multiple time units.
  • the photodetector is a single photon avalanche diode chip.
  • the pixel unit is a single pixel of the photodetector.
  • the pixel unit is two or more pixels of the photodetector.
  • the predetermined pixel unit is a single pixel unit of the photodetector.
  • the predetermined pixel unit is two or more pixel units of the photodetector.
  • the time unit with the highest total amount of the optical excitation signal is selected as the echo reflection time.
  • the first time is greater than or equal to the cumulative duration of the preset multiple time units.
  • the photodetector is a single photon avalanche diode chip.
  • the pixel unit is a single pixel of the photodetector.
  • the pixel unit is two or more pixels of the photodetector.
  • the predetermined pixel units are all pixel units of the photodetector.
  • the predetermined pixel unit is two or more pixel units of the photodetector.
  • a laser radar system comprising:
  • a laser configured to emit laser pulses into the detection area
  • a photodetector configured to generate a photoexcitation signal upon receipt of a photon signal
  • a controller configured to generate a plurality of time sequences of laser pulse emission timings for controlling the laser, each time sequence comprising a plurality of repeated cycle times and a plurality of randomly generated random times;
  • a collector which is configured to record the number of optical excitation signals that occur in predetermined pixel units of the photodetector within a plurality of preset time units each time the laser emits laser pulses according to the plurality of time sequences;
  • a comparator which is configured to count the total amount of optical excitation signals generated by predetermined pixel units of the photodetector within each time unit after the laser pulse emission of the plurality of time sequences is completed, and for each predetermined pixel unit, The time unit with the highest total amount of optical excitation signal is selected as the echo reflection time.
  • the pixel unit is a single pixel of the photodetector.
  • the pixel unit is two or more pixels of the photodetector.
  • the predetermined pixel units are all pixel units of the photodetector.
  • an electronic device including: at least one processor and a memory communicatively connected to the at least one processor, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor.
  • the at least one processor is executed to perform the method described in the present invention.
  • FIG. 1 shows a structural block diagram of an embodiment of a lidar system according to one or more embodiments
  • FIG. 2 shows a flowchart of a control method for a lidar system according to one or more embodiments
  • Fig. 3 shows a pixel schematic diagram of a single-photon avalanche diode (Single-Photon Avalanche Diode, hereinafter referred to as SPAD) sensor applied according to one or more embodiments;
  • SPAD Single-Photon Avalanche Diode
  • FIG. 4 shows another ambient light perception method for a lidar system according to one or more embodiments
  • FIG. 5 shows a schematic diagram of the steps of acquiring the number of optical excitation signals of a predetermined pixel unit in one or more examples of the method shown in FIG. 4 .
  • Fig. 1 shows a structural block diagram of an embodiment of a lidar system according to one or more embodiments, in which only some components, electronic devices or functional modules of the lidar system are shown.
  • Those skilled in the art can imagine that after understanding the corresponding principles, in order to realize related content, other related units, devices or modules need or can be added to the system in the figure.
  • the laser radar system includes a laser 1 and a controller 2, wherein the laser 1 emits a laser pulse to the detection area 3 under the control of the controller 2, and the laser pulse forms a diffuse reflection echo on the surface of the detection area in the form of a laser beam and is detected by the laser. Radar system detection for functions such as distance measurement of the detection area.
  • the laser 1 may be any form of laser known in the art, such as a semiconductor laser such as a distributed feedback laser or a vertical cavity surface emitting laser.
  • the controller sends a pulse signal to the laser according to a preset time sequence, and the laser emits a laser pulse to the detection area after receiving the pulse signal.
  • the controller 2 is used to send work instructions to the laser, such as pulse signals, to realize functions such as turning on and off the laser and adjusting laser pulse width, repetition frequency, and energy parameters.
  • the controller can be a dedicated electronic control device, or the control function can be realized through a central processing unit.
  • the controller is provided with a time control unit, which generates multiple time sequences for controlling laser pulse emission time points of the laser, each time sequence includes multiple repeated cycle times and multiple randomly generated random times.
  • the cycle time is set to recurring ⁇ T, and the random time is randomly generated ⁇ T 1 , ⁇ T 2 , ⁇ T 3 . . .
  • each time in this sequence is the time point when the laser starts to send laser pulses, n or the number of laser pulses sent in the sequence can be adjusted as needed set up.
  • the lidar system also includes a photodetector 4, which is configured to generate a light excitation signal when receiving an external light wave.
  • the photodetector 4 is, for example, a CCD light sensor, a CMOS sensor, a PD photodiode, an APD avalanche diode, a SPAD single photon avalanche diode, and the like.
  • the present invention employs a SPAD chip (Single Photon Avalanche Diode) as a photodetection sensor.
  • the SPAD chip is a digital chip with a pixel array composed of multiple pixels.
  • Each pixel is in an avalanche state under an external high voltage difference (in some special scenarios, its magnification is not the maximum state, and it can also be in a linear magnification state. Geiger pattern).
  • the avalanche state when each pixel receives the photon signal of laser diffuse reflection echo or external ambient light, it is excited and discharged by the photon signal, and the output value is "1". If it does not receive the laser diffuse reflection echo or external ambient light It is not excited, does not output any value or the output value is "0".
  • the laser radar system also includes a collector 5, which is configured to record the predetermined pixel units of the photodetectors within a plurality of preset time units during the process of the laser emitting each laser pulse according to the time sequence.
  • the number of photoexcitation signals For example, it can be set that each time the laser emitting module emits a beam of laser pulses to the detection area, start timing, every other time unit T unit , the output of the light excitation signal of each predetermined pixel unit of the photodetector within the time unit The situation is collected and recorded, a total of M time units, a total of Tsum time is required, and the results of M time units are stored in a register, for example.
  • the collector 5 includes a TDC circuit (Time-Distance Convert, time-distance conversion), which is connected with the SPAD chip to determine whether the laser is emitted and the SPAD photodetector detects the diffuse reflection echo of the laser
  • the time difference is used to calculate the distance from the detection area to the lidar.
  • the TDC circuit directly calculates the time difference of the laser pulse from emitting the laser to receiving the diffuse echo as the distance between the lidar system and the detection area, eliminating the need for optical signals-analog signals-digital signals when using other photosensitive elements
  • the signal change process has higher execution efficiency.
  • the lidar system also includes a comparator 6, which is configured to count the total amount of optical excitation signals generated by the predetermined pixel unit of the photodetector within each time unit after the laser pulse emission of the plurality of time sequences is completed , and for each predetermined pixel unit, the time unit with the highest total amount of optical excitation signal is selected as the echo reflection time, which is used, for example, to calculate the distance between the monitoring point and the emitting point.
  • a comparator 6 is configured to count the total amount of optical excitation signals generated by the predetermined pixel unit of the photodetector within each time unit after the laser pulse emission of the plurality of time sequences is completed , and for each predetermined pixel unit, the time unit with the highest total amount of optical excitation signal is selected as the echo reflection time, which is used, for example, to calculate the distance between the monitoring point and the emitting point.
  • the lidar system further includes a memory 7, which is, for example, a non-volatile computer-readable storage medium for storing non-volatile software programs, non-volatile computer-executable programs, modules, and the like.
  • the non-volatile software programs, instructions and modules stored in the memory are run by the controller or other processors to execute various functional applications and data processing of the system.
  • the memory may include a program storage area and a data storage area, wherein the program storage area may store, for example, an operating system, an application program required by at least one function, etc.; the data storage area may store, for example, an option list, a light intensity threshold table, and the like.
  • the memory may include memory that is remotely located relative to the processor, and these remote memories may be connected to external devices through a network. Examples of the network include but are not limited to the Internet, intranets, local area networks, mobile communication networks, and its combination.
  • Fig. 2 shows a kind of ambient light perception method for lidar system according to the present invention, and this method comprises:
  • the timing control unit in the controller of the lidar system generates a plurality of time sequences for controlling the emission timing of laser pulses emitted by the laser, each time sequence including a plurality of repeated cycle times and a plurality of A randomly generated random time.
  • the cycle time is set to recurring ⁇ T, and the random time is randomly generated ⁇ T 1 , ⁇ T 2 , ⁇ T 3 . . . ⁇ T 2 ), ( ⁇ T+ ⁇ T 3 )...( ⁇ T+ ⁇ T n ), each time in the sequence, that is, the sequence time is the time point when the laser starts to send laser pulses, n or the number of laser pulses sent in the sequence can be determined according to Settings are required.
  • S102 Transmit laser pulses to the detection area sequentially according to the time sequence.
  • the laser pulse can be a laser pulse emitted separately for detecting ambient light, or it can be a laser pulse emitted by the lidar in actual detection work.
  • the laser of the lidar system emits a laser pulse to the detection area under the control of the controller, and the laser pulse forms a diffuse reflection echo on the surface of the detection area in the form of a laser beam and is received by the photodetector A photoexcitation signal occurs.
  • the laser starts to work at a predetermined time, and emits a laser beam with predetermined parameters such as pulse width, repetition frequency, and energy.
  • the controller controls the laser to emit laser pulses to the detection area multiple times according to a pre-generated time sequence. For example, the first laser pulse is emitted in the time sequence ( ⁇ T+ ⁇ T 1 ), and then the second laser pulse is emitted in the time sequence ( ⁇ T+ ⁇ T 2 ), until the last laser pulse is completed in the time sequence ( ⁇ T+ ⁇ T n ). Laser pulses are emitted.
  • S103 Record the number of light excitation signals respectively generated by predetermined pixel units of the photodetector within each time unit.
  • a photodetector is generally provided with a plurality of pixel units.
  • the pixel unit is arranged, for example, as a single pixel on a photodetector.
  • the pixel unit is configured as two or more pixels on a photodetector, for example.
  • each pixel receives a photon signal, it is excited by the photon signal to generate an electrical signal, that is, an optical excitation signal.
  • the optical excitation signal can be detected and accumulated by a suitable collector.
  • Each time the laser emits laser pulses according to the time sequence is divided into multiple time units, and the collector detects and records the optical excitation signal of each pixel in each time unit. For example, it can be set that each time the laser emitting module emits a beam of laser pulses to the detection area, start timing, and check whether each predetermined pixel unit of the photodetector generates an optical excitation signal for each time unit T unit and record.
  • Fig. 3 shows the pixel schematic diagram of a kind of specific photodetector that the present invention is applied, and this photodetector is SPAD sensor for example, and this sensor is provided with pixel array (20 * 10), comprises 20 pixel units 42, each The pixel unit includes 10 pixels 41.
  • each pixel receives the photon signal of the laser diffuse reflection echo or the external ambient light, it is excited by the photon signal to discharge and output, and the output value is "1". If it is not excited, it is not Output any value or the output value is "0".
  • S104 Count the total amount of the optical excitation signal in each time unit, and select the time unit with the highest total amount of the optical excitation signal as the echo reflection time.
  • the total amount of optical excitation signals generated by the predetermined pixel units of the photodetector in each time unit is counted, and for each predetermined pixel unit, the highest total amount of optical excitation signals is selected respectively
  • the time unit of is used as the echo reflection time.
  • Fig. 4 shows another kind of ambient light perception method for lidar system according to the present invention, and this method comprises:
  • S201 Control the laser to emit the first laser pulse after the first time, and record the number of optical excitation signals respectively generated by the predetermined pixel unit of the photodetector within a plurality of preset time units;
  • S202 Control the laser to emit a second laser pulse after a second time, the second time is the sum of the first time and a randomly generated time, and record the predetermined pixel unit of the photodetector at the preset The number of photoexcitation signals occurring in multiple time units respectively;
  • FIG. 5 shows a schematic diagram of the steps of acquiring the number of optical excitation signals of a predetermined pixel unit in one or more examples of the method shown in FIG. 4 .
  • the time control unit generates the first time sequence ⁇ T, and sends the first pulse signal to the laser emitting module, and the laser emits the first laser pulse to the detection area.
  • the process of the first laser pulse emission is divided into 16 time units T unit .
  • TDC starts counting, every other time unit T unit , the output of each SPAD photodetector pixel in the time unit is recorded, totaling M time units, a total of T sum time is required, and Store the M time unit results eg in a register.
  • the time control unit generates a second time sequence ⁇ T+ ⁇ T1', and sends out a second signal pulse after the second time sequence.
  • the process of the second laser pulse emission is divided into 16 time units T unit .
  • the TDC starts to count, every other time unit T unit , the output of each SPAD photodetector pixel in the time unit is collected and recorded, a total of M time units, a total of T sum time is required, And store the results of M time units, for example, into a register.
  • the laser radar After the laser radar sends out n pulse signals, read the output of the optical excitation signal of each time unit of each pixel and perform cumulative calculations to generate a histogram, and select the time corresponding to the highest value in the histogram as the target echo Reflection time, and converted to distance.
  • the time series of the above steps include the recurring cycle time ⁇ T and random production time ⁇ T 1 ′, ⁇ T 2 ′, ⁇ T 3 ′... ⁇ T n-1 ′ , thus forming the time series ( ⁇ T+ ⁇ T 1 ′ ), ( ⁇ T+ ⁇ T 2 '), ( ⁇ T+ ⁇ T 3 ')...( ⁇ T+ ⁇ T n-1 '), each sequence time in this sequence is the time point when the laser starts to send laser pulses, n or laser pulses in the sequence The number of pulses sent can be set as required.
  • the signal light interference problem caused by three different interference light sources has a good anti-interference effect.
  • This solution does not need to encode the laser pulse signal, nor does it need to judge whether the code of the signal received by the photoelectric sensor matches the laser pulse code, so it greatly simplifies the process of testing the target area of the laser radar, making the laser radar more efficient, accurate and Greater stability.
  • This solution also does not need to set a threshold for the received echo signal, so there is no need to adjust the threshold according to the intensity of the random light source, and the lidar is easy to use, which increases the convenience of the lidar.
  • the storage medium includes: various media capable of storing program codes such as U disk, mobile hard disk, read-only memory, random access memory, magnetic disk or optical disk.

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  • Computer Networks & Wireless Communication (AREA)
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  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
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Abstract

一种用于激光雷达系统的控制方法，包括：生成用于控制激光脉冲发射时点的时间序列（S101），该时间序列中的每个序列时间为重复出现的周期时间和随机产生的随机时间之和、并且分隔为多个时间单元；根据该时间序列依次向探测区域发射激光脉冲（S102）；在每次发射激光脉冲的过程中，记录光电探测器的预定像素单元在多个时间单元内分别发生的光激发信号数量（S103）；在根据该时间序列完成全部激光脉冲发射后，统计预定像素单元在各个时间单元内所发生的光激发信号总量，并针对各个预定像素单元，分别选取光激发信号总量最高的时间单元作为回波反射时间（S104）。

Description

激光雷达系统及其控制方法
本申请要求于2022年1月13日递交的中国专利申请第202210034785.9号的优先权，在此全文引用上述中国专利申请公开的内容以作为本申请的一部分。
技术领域
本公开涉及激光雷达技术，尤其涉及激光雷达的抗干扰方法和系统。
背景技术
激光雷达在实际使用中，会受到环境光源的干扰。环境光源一般包含三类：与所述激光雷达同频光源、与所述激光雷达不同频光源、以及随机频率的光源。例如多个相同激光雷达所发出的激光属于同频光源，不同的激光雷达发出的光源属于不同频光源，路上的路灯、太阳光、建筑灯光等其它发光体发出的光源具有随机性，为随机频率的光源。
现有技术对同频光源和不同频光源，通常在激光雷达的发射端加入编码以判断接收的回波信号是否为自身激光雷达发射的信号。这种做法的关键之处在于获得目标点反射回来的激光脉冲，以识别其脉冲编码，并与发射端编码进行比较。然而，激光雷达会受到环境光和目标点的影响，并不能准确检测到回波激光脉冲，且在比较脉冲编码时容易造成误差，影响雷达的准确性。另外，就随机频率光源所产生的干扰，现有技术一般对回波信号设置阈值以过滤干扰。但是，所述阈值需要根据随机光源的强度进行设置。由于随机光 源的强度会随时变换，阈值也需要相应地做出调整，从而会增加激光雷达的使用难度。
发明内容
本公开针对现有技术的缺陷，改进了激光雷达的相关技术做进一步改进，以提高激光雷达系统的便利性和准确性。
一方面，提供一种用于激光雷达系统的控制方法，该方法包括：
生成用于控制激光脉冲发射时点的时间序列，该时间序列中的每个序列时间为重复出现的周期时间和随机产生的随机时间之和、并且分隔为多个时间单元；
根据所述时间序列依次向探测区域发射激光脉冲；
在每次发射激光脉冲的过程中，记录光电探测器的预定像素单元在所述多个时间单元内分别发生的光激发信号数量；
在根据所述时间序列完成全部激光脉冲发射后，统计所述预定像素单元在各个时间单元内所发生的光激发信号总量，并针对各个预定像素单元，分别选取光激发信号总量最高的时间单元作为回波反射时间。
有益的是，所述时间序列的第一个序列时间的随机时间被替换为零。
有益的是，所述周期时间大于或等于所述预设的多个时间单元的累积时长。
有益的是，所述光电探测器为单光子雪崩二极管芯片。
有益的是，所述像素单元为所述光电探测器的单个像素。
有益的是，所述像素单元为所述光电探测器的两个或两个以上像素。
有益的是，所述预定像素单元为光电探测器的单个像素单元。
有益的是，所述预定像素单元为光电探测器的两个或两个以上像素单元。
另一方面，提供另一种用于激光雷达系统的控制方法，该方法包括：
控制激光器在第一时间后发射第一次激光脉冲，并记录光电探测器的预定像素单元在预设的多个时间单元内分别发生的光激发信号数量；
控制激光器在第二时间后发射第二次激光脉冲，该第二时间为所述第一时间和一个随机生成的时间之和，并记录光电探测器的预定像素单元在所述预设的多个时间单元内分别发生的光激发信号数量；
重复前一步骤至预定次数后，统计光电探测器的预定像素单元在各个时间单元内所发生的光激发信号总量；
针对各个预定像素单元，分别选取光激发信号总量最高的时间单元作为回波反射时间。
有益的是，所述第一时间大于或等于所述预设的多个时间单元的累积时长。
有益的是，所述光电探测器为单光子雪崩二极管芯片。
有益的是，所述像素单元为所述光电探测器的单个像素。
有益的是，所述像素单元为所述光电探测器的两个或两个以上像素。
有益的是，所述预定像素单元为光电探测器的所有像素单元。
有益的是，所述预定像素单元为光电探测器的两个或两个以上像素单元。
又一方面，提供一种激光雷达系统，包括：
激光器，其被设置为向探测区域发射激光脉冲；
光电探测器，其被设置为在接收到光子信号时发生光激发信号；
控制器，其被设置为生成用于控制激光器的激光脉冲发射时点的多个时间序列，每个时间序列包括多个重复的周期时间和多个随机产生的随机时间；
采集器，其被设置为在每次激光器根据所述多个时间序列发射激光脉冲的过程中，记录光电探测器的预定像素单元在预设的多个时间单元内分别发生的光激发信号数量；
比较器，其被设置为在完成所述多个时间序列的激光脉冲发射后，统计光电探测器的预定像素单元在各个时间单元内所发生的光激发信号总量，并且针对各个预定像素单元，分别选取光激发信号总量最高的时间单元作为回波反射时间。
有益的是，所述像素单元为所述光电探测器的单个像素。
有益的是，所述像素单元为所述光电探测器的两个或两个以上像素。
有益的是，所述预定像素单元为光电探测器的所有像素单元。
又一方面，提供一种电子设备，包括：至少一个处理器以及与所述至少一个处理器通信连接的存储器，该存储器存储有可被所述至少一个处理器执行的指令，所述指令被所述至少一个处理器执行以执行本发明所述的方法。
附图说明
以下将结合附图进一步详细介绍本公开方案的其他细节和优点，其中：
图1示出了根据一个或多个实施例的激光雷达系统的实施例的结构框图；
图2示出了根据一个或多个实施例的用于激光雷达系统的控制方法流程图；
图3示出了根据一个或多个实施例所应用的一种单光子雪崩二极管 (Single-Photon Avalanche Diode,下称SPAD)传感器的像素示意图；
图4示出了根据一个或多个实施例的另一种用于激光雷达系统的环境光感知方法；
图5示出了图4所示方法的一个或多个实例中获取预定像素单元的光激发信号数量的步骤示意图。
具体实施方式
图1示出了根据一个或多个实施例的激光雷达系统的实施例的结构框图，图中仅示出了激光雷达系统的部分组成单元、电子器件或者功能模块。本领域技术人员在明白相应原理后可以想到，为了实现相关内容，图中系统需要或者可以增加其他相关的单元、器件或者模块。
所述激光雷达系统包括激光器1和控制器2，其中激光器1在控制器2的控制下向探测区域3发射激光脉冲，该激光脉冲以激光束的形式在检测区域表面形成漫反射回波被激光雷达系统检测，以实现例如探测区域的距离测量等功能。
所述激光器1可以为本领域已知的任何形式的激光器，例如分布式反馈激光器或垂直腔面发射激光器等半导体激光器。在一个或多个实例中，控制器根据预设的时间序列向激光器发出脉冲信号，激光器在收到脉冲信号后向探测区域发射激光脉冲。
所述控制器2用于向激光器发出工作指令，例如脉冲信号等，以实现激光器的开启、关闭以及调节激光脉宽、重频、能量参数等功能。所述控制器可以为专用的电子控制器件，也可以通过中央处理器来实现所述控制功能。 尤其是，所述控制器设置时间控制单元，其生成用于控制激光器的激光脉冲发射时点的多个时间序列，每个时间序列包括多个重复的周期时间和多个随机产生的随机时间。例如，所述周期时间被设置为重复出现的ΔT，而所述随机时间为随机产生的ΔT 1、ΔT 2、ΔT 3……ΔT n,,从而构成时间序列(ΔT+ΔT 1)、(ΔT+ΔT 2)、(ΔT+ΔT 3)……(ΔT+ΔT n)，该序列中的每个时间为激光器开始发送激光脉冲的时点，序列中n或者激光脉冲的发送次数可以根据需要进行设定。
所述激光雷达系统还包括光电探测器4，其被设置为在接收到外部光波时发生光激发信号。所述光电探测器4例如为CCD光传感器、CMOS传感器、PD光电二极管、APD雪崩二极管、SPAD单光子雪崩二极管等。在一个或多个实例中，本发明采用SPAD芯片(单光子雪崩二极管)作为光电探测传感器。SPAD芯片是一种数字芯片，具有由多个像素组成的像素阵列，每个像素在外加高电压差下，处于雪崩状态(在一些特殊场景下其放大倍数非最大状态，也可以为线性放大状态的盖革模式)。在雪崩状态下，各个像素在接收到激光漫反射回波或者外部环境光的光子信号时，被光子信号激发放电，输出值为“1”，如果没有接收激光漫反射回波或者外在环境光则不被激发，不输出任何值或输出值为“0”。
所述激光雷达系统还包括采集器5，其被设置为在激光器根据所述时间序列发射每次激光脉冲的过程中，记录光电探测器的预定像素单元在预设的多个时间单元内分别发生的光激发信号数量。例如，可以设置每次激光发射模块向探测区域发射一束激光脉冲时，开始计时，每隔一个时间单元T unit，对该时间单元内光电探测器的每个预定像素单元的光激发信号的输出情况进行采 集记录，总计M个时间单元，共需Tsum时间，并将M个时间单元结果例如存入寄存器。
在一个或多个实例中，所述采集器5包括TDC电路(Time-Distance Convert，时间距离转换)，其与SPAD芯片连接，以确定激光发射以及SPAD光电探测器检测到激光漫反射回波的时间差，以计算出探测区域到激光雷达的距离，计算公式为：S＝光速×时间差/2。TDC电路通过将激光脉冲从发射激光至收到漫反射回波的时间差直接计算成激光雷达系统与检测区域之间的距离，省去使用其他感光元件时所需的光信号-模拟信号-数字信号的信号变化流程，具有更高的执行效率。
所述激光雷达系统还包括比较器6，其被设置为在完成所述多个时间序列的激光脉冲发射后，统计光电探测器的预定像素单元在各个时间单元内所发生的光激发信号总量，并且针对各个预定像素单元，分别选取光激发信号总量最高的时间单元作为回波反射时间，用于例如计算监测点相距发射点的距离。
所述激光雷达系统还包括存储器7，其例如为一种非易失性计算机可读存储介质，用于存储非易失性软件程序、非易失性计算机可执行程序以及模块等。存储在存储器中的非易失性软件程序、指令以及模块等由控制器或者其他的处理器运行，以执行系统的各种功能应用以及数据处理。存储器可以包括程序存储区和数据存储区，其中，程序存储区可存储例如操作系统、至少一个功能所需要的应用程序等；数据存储区可存储例如选项列表、光强阈值表等。在一些实施例中，存储器可包括相对于处理器远程设置的存储器，这些远程存储器可以通过网络连接至外接设备，所述网络的实例包括但不限于 互联网、企业内部网、局域网、移动通信网及其组合。
图2示出了根据本发明的一种用于激光雷达系统的环境光感知方法，该方法包括：
S101：生成时间序列。
在一个或多个实例中，激光雷达系统的控制器中的时间控制单元生成用于控制激光器发射激光脉冲的发射时点的多个时间序列，每个时间序列包括多个重复的周期时间和多个随机产生的随机时间。
例如，所述周期时间被设置为重复出现的ΔT，所述随机时间为随机产生的ΔT 1、ΔT 2、ΔT 3……ΔT n,,从而构成时间序列(ΔT+ΔT 1)、(ΔT+ΔT 2)、(ΔT+ΔT 3)……(ΔT+ΔT n)，该序列中的每个时间即序列时间为激光器开始发送激光脉冲的时点，序列中n或者激光脉冲的发送次数可以根据需要进行设定。
S102：根据时间序列依次向探测区域发射激光脉冲。
激光脉冲作为检测信号源，可以是为了检测环境光而单独发射的激光脉冲，也可以是激光雷达在实际探测工作中所发射的激光脉冲。在一个或多个实例中，激光雷达系统的激光器在控制器的控制下向探测区域发射激光脉冲，该激光脉冲以激光束的形式在检测区域表面形成漫反射回波并被光电探测器接收而发生光激发信号。例如，根据激光雷达系统的控制器发出的工作指令，激光器在预定时间开始工作，发出具有预定脉宽、重频、能量等参数的激光束。
尤其是，控制器控制激光器根据预先产生的时间序列多次向探测区域发射激光脉冲。例如，首先在时间序列(ΔT+ΔT 1)发射第一束激光脉冲，然后 在时间序列(ΔT+ΔT 2)发射第二束激光脉冲，一直到在时间序列(ΔT+ΔT n)完成最后一次激光脉冲发射。
S103：记录光电探测器的预定像素单元在各个时间单元内分别发生的光激发信号数量。
光电探测器一般设置有多个像素单元。在一个或多个实例中，所述像素单元例如被设置为光电探测器上的单个像素。在另一个或多个实例中，所述像素单元例如被设置为光电探测器上的两个或两个以上像素。每个像素在接收到光子信号时，被光子信号激发产生电信号，即光激发信号，该光激发信号可以被合适的采集器进行检测和累加统计。
在激光器每一次根据所述时间序列发射激光脉冲的过程划分为多个时间单元，采集器在每个时间单元对各个像素的光激发信号进行检测和纪录。例如，可以设置每次激光发射模块向探测区域发射一束激光脉冲时，开始计时，对每个隔一个时间单元T unit，对光电探测器的每个预定像素单元是否产生光激发信号进行检测和纪录。
图3示出了本发明所应用的一种具体光电探测器的像素示意图，该光电探测器例如为SPAD传感器，该传感器设置有像素阵列(20×10)，包括20个像素单元42，每个像素单元包括10个像素41，每个像素在接收到激光漫反射回波或者外在环境光的光子信号时，被光子信号激发放电输出，输出值为“1”，如果没有被激发，则不输出任何值或输出值为“0”。如图中所示，在一个特定时间序列的激光发射过程的特定时间单元，所述像素单元内的10个像素被光信号激光，采集器采集每个像素每个时间单元内的激光量。其他的像素单元也以同样的方法进行检测，以确定各个像素单元在该时间序列的激光发射过 程的特定时间单元的光激发信号数量。
S104：统计各个时间单元内的光激发信号总量，并分别选取光激发信号总量最高的时间单元作为回波反射时间。
在根据所述时间序列完成全部激光脉冲发射后，统计光电探测器的预定像素单元在各个时间单元内所发生的光激发信号总量，并针对各个预定像素单元，分别选取光激发信号总量最高的时间单元作为回波反射时间。
图4示出了根据本发明的另一种用于激光雷达系统的环境光感知方法，该方法包括：
S201：控制激光器在第一时间后发射第一次激光脉冲，并记录光电探测器的预定像素单元在预设的多个时间单元内分别发生的光激发信号数量；
S202：控制激光器在第二时间后发射第二次激光脉冲，该第二时间为所述第一时间和一个随机生成的时间之和，并记录光电探测器的预定像素单元在所述预设的多个时间单元内分别发生的光激发信号数量；
S203:重复前一步骤S202至预定次数后，统计光电探测器的预定像素单元在各个时间单元内所发生的光激发信号总量；
S204：针对各个预定像素单元，分别选取光激发信号总量最高的时间单元作为回波反射时间。
图5示出了图4所示方法的一个或多个实例中获取预定像素单元的光激发信号数量的步骤示意图。
首先，时间控制单元产生第一时间序列ΔT，并向激光发射模块发出第一次脉冲信号，激光器向探测区域发射第一次激光脉冲。该第一次激光脉冲发射的过程被分隔成16个时间单元T unit。从开始发射激光脉冲时，TDC开始计 时，每隔一个时间单元T unit，对该时间单元内每一个SPAD光电探测器像素的输出情况进行记录，总计M个时间单元，共需T sum时间，并将M个时间单元结果例如存入寄存器。
之后，时间控制单元产生第二时间序列ΔT+ΔT1＇，并在该第二时间序列后发出第二次信号脉冲。与前一步骤一样，该第二次激光脉冲发射的过程被分隔成16个时间单元T unit。从开始发射激光脉冲时，TDC开始计时，每隔一个时间单元T unit，对该时间单元内每一个SPAD光电探测器像素的输出情况进行采集记录，总计M个时间单元，共需T sum时间，并将M个时间单元结果例如存入寄存器。
重复前一步骤n-1次，以完成预定的n次激光脉冲发射测试。
在激光雷达发出n次脉冲信号后，读取每一像素的每个时间单元的光激发信号输出情况并进行累加运算，生成直方图，选取直方图中最高的值所对应的时间为目标回波反射的时间，并换算成距离。
以上步骤的时间序列包括重复出现的周期时间ΔT和随机生产的随机时间ΔT 1＇、ΔT 2＇、ΔT 3＇……ΔT n-1＇ ,,从而构成时间序列(ΔT+ΔT 1＇)、(ΔT+ΔT 2＇)、(ΔT+ΔT 3＇)……(ΔT+ΔT n-1＇)，该序列中的每个序列时间为激光器开始发送激光脉冲的时点，序列中n或者激光脉冲的发送次数可以根据需要进行设定。
在本实施例中，对三种不同的干扰光源所造成的信号光干扰问题，都有很好的抗干扰效果。本方案无需对激光脉冲信号进行编码，对光电传感器接收到的信号也无需判断其编码是否与激光脉冲编码匹配，因此大大简化了激光雷达测试目标区域的流程，使激光雷达更高效，准确性和稳定性更高。本 方案也无需对接收的回波信号设置阈值，因此不用根据随机光源的强度调整阈值，激光雷达使用简单，增加了激光雷达的使用便利性。
本领域技术人员可以明白，实现上述实施例方法中的全部或部分步骤可以通过程序来指令相关的硬件予以执行，该程序存储在存储介质中，包括若干指令以使得一个设备(可以是单片机，芯片等)或处理器执行本申请各实施例所述方法的全部或部分步骤。所述存储介质包括：U盘、移动硬盘、只读存储器、随机存取存储器、磁碟或者光盘等各种能够存储程序代码的介质。

Claims (20)

  1. 一种用于激光雷达系统的控制方法，该方法包括：
    生成用于控制激光脉冲发射时点的时间序列，该时间序列中的每个序列时间为重复出现的周期时间和随机产生的随机时间之和、并且分隔为多个时间单元；
    根据所述时间序列依次向探测区域发射激光脉冲；
    在每次发射激光脉冲的过程中，记录光电探测器的预定像素单元在所述多个时间单元内分别发生的光激发信号数量；
    在根据所述时间序列完成全部激光脉冲发射后，统计所述预定像素单元在各个时间单元内所发生的光激发信号总量，并针对各个预定像素单元，分别选取光激发信号总量最高的时间单元作为回波反射时间。
  2. 根据权利要求1所述的控制方法，其特征在于，所述时间序列的第一个序列时间的随机时间被替换为零。
  3. 根据权利要求1所述的控制方法，其特征在于，所述周期时间大于或等于所述预设的多个时间单元的累积时长。
  4. 根据权利要求1所述的控制方法，其特征在于，所述光电探测器为单光子雪崩二极管芯片。
  5. 根据权利要求1所述的控制方法，其特征在于，所述像素单元为所述光电探测器的单个像素。
  6. 根据权利要求1所述的控制方法，其特征在于，所述像素单元为所述光电探测器的两个或两个以上像素。
  7. 根据权利要求1所述的控制方法，其特征在于，所述预定像素单元为光电探测器的单个像素单元。
  8. 根据权利要求1所述的控制方法，其特征在于，所述预定像素单元为光电探测器的两个或两个以上像素单元。
  9. 一种用于激光雷达系统的控制方法，该方法包括：
    控制激光器在第一时间后发射第一次激光脉冲，并记录光电探测器的预定像素单元在预设的多个时间单元内分别发生的光激发信号数量；
    控制激光器在第二时间后发射第二次激光脉冲，该第二时间为所述第一时间和一个随机生成的时间之和，并记录光电探测器的预定像素单元在所述预设的多个时间单元内分别发生的光激发信号数量；
    重复前一步骤至预定次数后，统计光电探测器的预定像素单元在各个时间单元内所发生的光激发信号总量；
    针对各个预定像素单元，分别选取光激发信号总量最高的时间单元作为回波反射时间。
  10. 根据权利要求9所述的控制方法，其特征在于，所述第一时间大于或等于所述预设的多个时间单元的累积时长。
  11. 根据权利要求9所述的控制方法，其特征在于，所述光电探测器为单光子雪崩二极管芯片。
  12. 根据权利要求9所述的控制方法，其特征在于，所述像素单元为所述光电探测器的单个像素。
  13. 根据权利要求9所述的控制方法，其特征在于，所述像素单元为所述光电探测器的两个或两个以上像素。
  14. 根据权利要求9所述的控制方法，其特征在于，所述预定像素单元为光电探测器的所有像素单元。
  15. 根据权利要求9所述的控制方法，其特征在于，所述预定像素单元为光电探测器的两个或两个以上像素单元。
  16. 一种激光雷达系统，包括：
    激光器，其被设置为向探测区域发射激光脉冲；
    光电探测器，其被设置为在接收到光子信号时发生光激发信号；
    控制器，其被设置为生成用于控制激光器的激光脉冲发射时点的多个时间序列，每个时间序列包括多个重复的周期时间和多个随机产生的随机时间；
    采集器，其被设置为在每次激光器根据所述多个时间序列发射激光脉冲的过程中，记录光电探测器的预定像素单元在预设的多个时间单元内分别发生的光激发信号数量；
    比较器，其被设置为在完成所述多个时间序列的激光脉冲发射后，统计光电探测器的预定像素单元在各个时间单元内所发生的光激发信号总量，并且针对各个预定像素单元，分别选取光激发信号总量最高的时间单元作为回波反射时间。
  17. 根据权利要求16所述的激光雷达系统，其特征在于，所述像素单元为所述光电探测器的单个像素。
  18. 根据权利要求16所述的激光雷达系统，其特征在于，所述像素单元为所述光电探测器的两个或两个以上像素。
  19. 根据权利要求16所述的激光雷达系统，其特征在于，所述预定像素单元为光电探测器的所有像素单元。
  20. 一种电子设备，包括：至少一个处理器以及与所述至少一个处理器通信连接的存储器，该存储器存储有可被所述至少一个处理器执行的指令，其特征在于，所述指令被所述至少一个处理器执行以执行权利要求1-15中任一项所述的方法。
PCT/CN2022/076479 2022-01-13 2022-02-16 激光雷达系统及其控制方法 WO2023133963A1 (zh)

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