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CN117665762A - Laser radar and emission energy adjusting method and system thereof - Google Patents

Laser radar and emission energy adjusting method and system thereof Download PDF

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Publication number
CN117665762A
CN117665762A CN202211007769.7A CN202211007769A CN117665762A CN 117665762 A CN117665762 A CN 117665762A CN 202211007769 A CN202211007769 A CN 202211007769A CN 117665762 A CN117665762 A CN 117665762A
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intensity
light intensity
laser
light
detector
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Inventor
梁峰
向少卿
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Hesai Technology Co Ltd
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Hesai Technology Co Ltd
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Priority to CN202211007769.7A priority Critical patent/CN117665762A/en
Priority to PCT/CN2023/078500 priority patent/WO2024040899A1/en
Publication of CN117665762A publication Critical patent/CN117665762A/en
Pending legal-status Critical Current

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483Details of pulse systems
    • G01S7/484Transmitters
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S17/00Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06Systems determining position data of a target
    • G01S17/08Systems determining position data of a target for measuring distance only
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S17/00Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88Lidar systems specially adapted for specific applications
    • G01S17/93Lidar systems specially adapted for specific applications for anti-collision purposes
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/4802Details 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
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02ATECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Electromagnetism (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

Laser radar, and emission energy adjusting method and system thereof, wherein the method comprises the following steps: according to the intensity of the echo signal preset and received by the detector, calculating the luminous intensity which is adopted next time by the corresponding laser; the calculated light intensity is compared with the threshold light intensity of the laser, the light intensity of a detection signal emitted next time by the laser is determined based on a comparison result, and the threshold light intensity of the laser is larger than the lower limit light intensity of the laser, so that deterioration conditions such as unstable light emission and the like of the laser are reduced or even avoided, and the accuracy of laser radar detection can be effectively improved.

Description

Laser radar and emission energy adjusting method and system thereof
Technical Field
The embodiment of the specification relates to the technical field of laser radars, in particular to a laser radar and a method and a system for adjusting emission energy of the laser radar.
Background
The laser radar is a commonly used ranging sensor, has the advantages of long detection distance, high resolution, small volume, light weight and the like, and is widely applied to the fields of intelligent robots, unmanned aerial vehicles, automatic driving and the like. As a three-dimensional measurement system, a lidar achieves three-dimensional coverage of a Field of View (FOV) of a measurement through an acquired point cloud. Since the reflectivity of different obstacles and the relative distance to the lidar may vary greatly, the echo signal received by the receiver may be small or large. In order to make the received signal in a preferred operation area of a receiver, many high-performance lidars support a function of dynamically adjusting the emitted light intensity. In a measurement scene with high reflectivity or relatively close obstacles, the adjustment scheme often requires that the laser emits light with smaller light intensity.
However, in practical application, the stability, consistency, temperature drift characteristics and other performances of the emission power are significantly deteriorated after the emission energy of the laser is reduced to a certain extent. Specifically, if a laser is driven electrically with a small power, the emitted light power actually emitted therefrom is dithered greatly. And the statistical dispersion of the power performance of the emergent light of different lasers is increased when the light intensity is small, and in addition, the temperature drift coefficient of the emergent power of the lasers is larger when the light intensity is small. Both of these conditions may result in poor accuracy of the distance and reflectivity of the radar to the target reflector.
The matters in the background section are only those known to the public and do not, of course, represent prior art in the field.
Disclosure of Invention
In view of this, the embodiments of the present disclosure provide a laser radar, and a method and a system for adjusting emission energy thereof, which can reduce or even avoid deterioration such as unstable light emission of a laser, and effectively improve the accuracy of laser radar detection.
First, an embodiment of the present specification provides a method for adjusting emission energy of a lidar, the method including:
according to the intensity of the echo signal preset and received by the detector, calculating the light intensity of the corresponding laser which emits light next time;
And comparing the calculated light intensity with the threshold light intensity of the laser, and determining the light intensity of the detection signal emitted next time by the laser based on the comparison result, wherein the threshold light intensity of the laser is higher than the lower limit light intensity of the laser.
Optionally, when the intensity of the echo signal received by the detector is within the preset intensity of the echo signal received by the detector, the detection efficiency of the detector is greater than a preset efficiency threshold.
Optionally, calculating the light intensity of the next light emission of the corresponding laser according to the intensity of the echo signal preset and received by the detector includes:
determining that the intensity of the preset received echo signal is between a first intensity and a second intensity, wherein the first intensity is larger than the second intensity;
and calculating the light intensity of the next light emission of the corresponding laser according to the first intensity, the second intensity, the current light emission intensity of the laser and the current received echo intensity of the detector.
Optionally, the calculating the light intensity of the next light emission of the corresponding laser according to the first intensity, the second intensity, the current light emission intensity of the laser, and the current intensity of the echo received by the detector respectively includes:
Calculating the first emission light intensity of the corresponding laser according to the first intensity, the current luminous intensity of the laser and the current intensity of the echo received by the detector;
calculating second emission light intensity of the corresponding laser according to the second intensity, the current luminous intensity of the laser and the current intensity of the echo received by the detector;
according to the relation among the first emission light intensity of the laser obtained by calculation of the first intensity, the second emission light intensity of the laser obtained by calculation of the second intensity, the upper limit light intensity and the lower limit light intensity of the laser, the first light intensity and the second light intensity are obtained by calculation respectively, the first light intensity is higher than the second light intensity, and the first emission light intensity and the second emission light intensity are both located between the first light intensity and the second light intensity.
Optionally, the calculating according to the relation between the first emission light intensity of the laser calculated by using the first intensity, the second emission light intensity of the laser calculated by using the second intensity, the upper limit light intensity and the lower limit light intensity of the laser, respectively, obtains the first light intensity and the second light intensity, includes:
selecting the smaller one of the first emission light intensity of the laser obtained by calculation by adopting the first intensity and the upper limit light intensity of the laser, and then comparing the selected smaller one with the larger one of the lower limit light intensity of the laser to obtain the first light intensity;
And selecting the larger one of the second emission light intensity of the laser obtained by calculation by adopting the second intensity and the lower limit light intensity of the laser, and comparing the selected larger one with the smaller one of the upper limit light intensity of the laser to obtain the second light intensity.
Optionally, the comparing the calculated emitted light intensity with the threshold light intensity of the laser, and determining the light intensity of the detection signal emitted by the laser next time based on the comparison result includes:
comparing the relation between the threshold light intensity of the laser and the first light intensity and the second light intensity;
and if the threshold light intensity of the laser is between the first light intensity and the second light intensity, determining the light intensity of the detection signal transmitted by the laser next time as the threshold light intensity.
Optionally, the method further comprises:
if the threshold light intensity of the laser is not between the first light intensity and the second light intensity, selecting the light intensity of the detection signal emitted by the laser next time as the light intensity of the detection signal which is closer to the threshold light intensity in the first light intensity and the second light intensity.
Optionally, the selecting, as the light intensity of the detection signal emitted next by the laser, a light intensity closer to the threshold light intensity from among the first light intensity and the second light intensity includes:
And selecting the larger one of the threshold light intensity and the second light intensity, and comparing the selected larger one with the smaller one of the first light intensity to be used as the light intensity of the detection signal emitted by the laser next time.
Optionally, the method further comprises:
and setting the lower limit light intensity of the laser, so that the intensity of the received echo signal is smaller than a preset receiving intensity threshold when the detector detects that the reflectivity exceeds the preset reflectivity threshold.
Correspondingly, the embodiment of the invention also provides a laser radar emission energy adjusting system, which comprises:
the emitted light intensity calculating unit is suitable for calculating the light intensity of the corresponding laser which emits light next time according to the preset intensity of the received echo signal of the detector;
and the emitted light intensity determining unit is suitable for comparing the calculated light intensity with the threshold light intensity of the laser, and determining the light intensity of the detection signal emitted next time by the laser based on the comparison result, wherein the threshold light intensity of the laser is higher than the lower limit light intensity of the laser.
Correspondingly, the embodiment of the invention also provides a laser radar, which comprises:
a laser adapted to emit a detection signal;
The detector is suitable for receiving echo signals of the detection signals reflected by the obstacle;
the processor is suitable for presetting the intensity of the received echo signal according to the preset detector and calculating the light intensity of the corresponding laser emitted next time; and comparing the calculated light intensity with the threshold light intensity of the laser, and determining the light intensity of the detection signal emitted next time by the laser based on the comparison result, wherein the threshold light intensity of the laser is greater than the lower limit light intensity of the laser.
Optionally, when the intensity of the echo signal received by the detector is within the preset intensity of the echo signal received by the detector, the detection efficiency of the detector is greater than a preset efficiency threshold.
Optionally, the processor is adapted to determine that the intensity of the preset received echo signal is between a first intensity and a second intensity, where the first intensity is greater than the second intensity, and calculate the intensity of the next light emission of the corresponding laser according to the first intensity, the second intensity, the current light emission intensity of the laser, and the current intensity of the echo received by the detector, respectively.
Optionally, the processor is adapted to calculate the first emission light intensity of the corresponding laser according to the first intensity, the current light emission intensity of the laser, and the current intensity of the echo received by the detector; calculating second emission light intensity of the corresponding laser according to the second intensity, the current luminous intensity of the laser and the current intensity of the echo received by the detector; and respectively calculating the first light intensity and the second light intensity according to the relation among the emission light intensity of the laser obtained by calculating the first intensity, the emission light intensity of the laser obtained by calculating the second intensity and the upper limit light intensity and the lower limit light intensity of the laser.
Optionally, the processor is adapted to select a smaller one of the first emission light intensity of the laser obtained by calculation using the first intensity and the upper limit light intensity of the laser, and then compare the selected smaller one with a larger one of the lower limit light intensity of the laser to obtain the first light intensity; and selecting the larger one of the second emission light intensity of the laser obtained by calculation by adopting the second intensity and the lower limit light intensity of the laser, and comparing the selected larger one with the smaller one of the upper limit light intensity of the laser to obtain the second light intensity.
Optionally, the processor is adapted to compare a threshold light intensity of the laser with the first light intensity and the second light intensity; if the threshold light intensity of the laser is between the first light intensity and the second light intensity, determining the light intensity of the detection signal emitted by the laser next time as the threshold light intensity; otherwise, selecting the light intensity of the detection signal emitted by the laser next time as the light intensity of the detection signal which is closer to the threshold light intensity in the first light intensity and the second light intensity.
By adopting the laser radar and the emission energy adjustment scheme thereof provided by the embodiment of the specification, when the determination of the light intensity of the next luminescence is carried out, the working characteristics of the laser and the detector are comprehensively considered, and specifically: on one hand, the intensity of the light emitted by the corresponding laser next time is calculated according to the preset echo intensity received by the detector next time, so that the calculated emitted light intensity considers the working characteristic of the detector; on the other hand, the light intensity of the detection signal emitted by the laser next time is determined by comparing the calculated light intensity of the laser with the threshold light intensity of the laser, wherein the threshold light intensity of the laser is larger than the lower limit light intensity of the laser, and when the emitted light intensity of the laser is larger than the threshold light intensity, the laser cannot emit light under the condition of poor stability and consistency, so that the light intensity of the detection signal emitted by the laser next time can meet the performance requirement of the laser, the occurrence of performance deterioration caused by unstable light emission, poor consistency and the like of the laser is reduced or even avoided, and the overall measurement accuracy of the laser radar can be effectively improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present description, the drawings that are required to be used in the embodiments of the present description or the description of the prior art will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present description, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 shows a schematic view of a laser radar structure and detection scenario;
FIG. 2 is a flow chart of a method for adjusting the transmit energy of a lidar according to an embodiment of the present invention;
fig. 3A to 3C are schematic diagrams showing possible values of the light intensity of a detection signal emitted by a laser according to an embodiment of the present invention;
FIG. 4 is a schematic diagram showing a graph of a method for adjusting the transmitted energy of a lidar according to an embodiment of the present invention;
FIG. 5 is a schematic diagram showing the structure of a laser radar emission energy adjustment system according to an embodiment of the present invention;
fig. 6 shows a schematic structural diagram of a lidar according to an embodiment of the present invention.
Detailed Description
In order to improve the accuracy of the laser radar in the measurement distance and the reflectivity of a high-reflectivity scene, the embodiment of the invention provides a transmission energy adjustment scheme of the laser radar, and comprehensively considers the working characteristics of a laser and a detector so as to reduce or even avoid the problem of light-emitting instability caused by using extremely small light intensity (even lower limit light intensity) as much as possible, thereby improving the stability and consistency of the whole transmission energy of the laser radar and further effectively improving the measurement accuracy of the laser radar.
Specifically, in the embodiment of the invention, the intensity of the corresponding laser can be calculated according to the intensity of the echo signal preset and received by the detector, and then the calculated emission intensity is compared with the threshold intensity of the laser, and the intensity of the detection signal emitted next time by the laser is determined based on the comparison result, so that the laser uses the lower limit intensity as little as possible.
In a specific implementation, when the intensity of the echo signal received by the detector is within the preset intensity of the echo signal, the detection efficiency is relatively high, and may be greater than a preset efficiency threshold, such as greater than 75%, which indicates that 75% of photons incident on the photosensitive surface of the detector may be converted into an electrical signal and output from the detector. On the basis, the calculated emitted light intensity is compared with the threshold light intensity of the laser, the light intensity of the detection signal emitted next time by the laser is determined, the threshold light intensity of the laser is larger than the lower limit light intensity of the laser, the condition that the laser emits light by adopting extremely small light intensity (even the lower limit light intensity) can be reduced, and therefore the stability and consistency of the light emission of the laser can be improved, the accuracy of measuring distance and reflectivity of the laser radar under the scenes can be improved, and the overall measuring accuracy of the laser radar can be effectively improved.
In order to enable those skilled in the art to better understand and implement the invention, the technical conception, technical scheme, principle, effect and the like of the embodiments of the present invention are described in detail below with reference to the accompanying drawings in combination with specific examples and application scenarios.
Fig. 1 shows a schematic view of the structure and detection of a lidar. The lidar 10 is a detection system that can emit a laser beam to detect a characteristic amount such as a position, a speed, or the like of the obstacle 20. The working principle is that a laser beam (detection signal or laser signal) is emitted to the outside, then the received detection result (reflection signal or echo signal) reflected from the obstacle 20 is processed properly, and then the flight time difference and power of the detection signal are determined, so that the relevant information of the obstacle, such as the distance, azimuth, altitude, speed, gesture, even shape and other parameters of the obstacle 20 relative to the laser radar 10, can be obtained, and the detection, tracking and identification of the obstacle are completed.
The lidar 10 may generate point cloud data, and a frame of point cloud data may include a plurality of laser point data, where each laser point data may include X, Y, Z three-dimensional coordinate information after comprehensively considering the world coordinate system. Wherein the obstacle 20 may be any form of object within a certain distance of the lidar 10. For example, in an autopilot scenario, the obstacle 20 may be a vehicle, building, pedestrian, etc. in the vicinity of the lidar 10. For another example, in a 3D scan scene, the obstacle 20 may be any form of building in the scene in which the lidar 10 is located. This distance is the range limit of the lidar 10 and may be, for example, 200m, 250m, 300m or more.
With continued reference to fig. 1, lidar 10 may include a transmitting end TX and a receiving end RX. The transmitting terminal TX may include a plurality of lasers 11 and other transmitting lens groups (not shown) for collimating and the like, which are used for collimating and the like, the light beams emitted from the lasers 11, and the receiving terminal RX may include a plurality of detectors 12 and receiving lens groups (not shown) for converging and the like, which are used for converging echo signals.
More specifically, the Emitting terminal may employ any one or more types of light Emitting devices, for example, a vertical cavity surface Emitting Laser (Vertical Cavity Surface Emitting Laser, VCSEL), a photonic crystal structure surface Emitting semiconductor Laser (Photonic Crystal Surface-Emitting Laser, PCSEL), an edge Emitting Laser (Edge Emitting Laser, EEL), or the like. Similarly, the receiving end may employ any one or more types of photo-detecting devices, such as silicon photomultiplier (Silicone Photomultiplier, siPM), single photon avalanche diode (Single Photon Avalanche Diode, SPAD), avalanche photodiode (Avalanche Photo Diode, APD), etc.
It should be understood that the specific examples of light emitting devices and light detecting devices in the embodiments are not intended to limit the scope of the present invention, but are merely illustrative examples for facilitating understanding of the context of specific applications. In some embodiments of the present invention, the light emitting device may specifically include a plurality of light emitting units, each of which may include one or more light emitting points. The light detecting device may include: the plurality of detection units, and at least one detection unit and one light-emitting unit may constitute one detection channel. The laser signal beams emitted by the lasers of the laser radar are deflected by the emission lens (group), and are emitted to different directions when emitted from the laser radar. Each detection channel may be responsible for detection of a vertical orientation. The vertical orientation may be a direction parallel to the axis of rotation of the deflectable member in the lidar. The horizontal orientation may be a direction perpendicular to the laser radar axis of rotation.
As described above, in order to effectively improve the measurement accuracy of the lidar, in some embodiments of the present invention, an emission energy adjustment scheme capable of satisfying performance requirements of the laser and the detector is adopted, and referring to the flowchart of the emission energy adjustment method shown in fig. 2, the method specifically may include the following steps:
s01, calculating the light intensity of the corresponding laser which emits light next time according to the intensity of the echo signal received by the detector in a preset mode.
And when the intensity of the signal received by the detector is the preset received echo signal, the detection efficiency of the detector is larger than a preset efficiency threshold. In a specific implementation, the intensity of the preset received echo signal may be a range or interval of intensities, and when the intensity of the signal received by the detector is within the range of the preset received echo signal, the detection efficiency of the detector may be greater than a preset efficiency threshold, such as greater than 60% or greater than 75% or greater than 90%, and so on. Accordingly, in some embodiments of the present invention, two signal intensities are selected, one referred to as a first intensity and the other as a second intensity, the first intensity being greater than the second intensity, and the echo intensity of the echo signal expected or desired to be received by the probe may lie between the first intensity and the second intensity.
Therefore, if the intensity of the signal received by the detector is located between the first intensity and the second intensity when the laser radar is detected next time, the detector can be in higher photoelectric efficiency, and thus the sensitivity and the accuracy of the whole detection of the radar can be improved. For the detection of the lidar at different times, the nth time is referred to as the current time and the (n+1) th time is referred to as the next time for the sake of description accuracy and convenience.
In addition, under the condition that the distance between the obstacle and the laser radar is unchanged, a certain corresponding relation exists between the emitted light intensity of the laser and the intensity of the echo signal received by the detector in a certain detection, namely if the intensity of the echo signal of the detector in the (n+1) th detection is expected to be a certain value, the laser corresponds to the light intensity required in the (n+1) th detection, or the light intensity in the light emission. In addition, according to the preset received echo intensity range of the detector, the calculated luminous intensity of the laser may also be a threshold range, and may be set between the first light intensity and the second light intensity.
Therefore, in some embodiments of the present invention, when it is determined that the intensity of the preset received echo signal is between the first intensity and the second intensity, the intensity of the next light emitted by the corresponding laser may be calculated according to the first intensity, the second intensity, the current light emission intensity of the laser, and the current intensity of the echo signal received by the detector, respectively.
As a more specific example, the first emission light intensity of the corresponding laser may be calculated according to the first intensity, the current emission light intensity of the laser, and the current intensity of the echo signal received by the detector; and calculating the second emission light intensity of the corresponding laser according to the second intensity, the current light emission intensity of the laser and the current received echo signal intensity of the detector. Furthermore, the relation between the first emission light intensity of the laser obtained by calculating the first intensity, the second emission light intensity of the laser obtained by calculating the second intensity, and the upper limit light intensity and the lower limit light intensity of the laser can be used to calculate the first light intensity and the second light intensity respectively, and the first light intensity is larger than the second light intensity.
In a specific implementation, a smaller one of the first emission light intensity of the laser obtained by the calculation using the first intensity and the upper limit light intensity of the laser may be selected, and then the selected smaller one is compared with a larger one of the lower limit light intensity of the laser to obtain the first light intensity. And selecting the larger one of the second emission light intensity of the laser obtained by calculation by adopting the second intensity and the lower limit light intensity of the laser, and comparing the selected larger one with the smaller one of the upper limit light intensity of the laser to obtain the second light intensity.
S02, comparing the calculated light intensity with the threshold light intensity of the laser, and determining the light intensity of the detection signal emitted by the laser next time based on the comparison result.
By the step S02, the situation that the laser emits light with extremely small light intensity (for example, lower limit light intensity) can be reduced, and deterioration such as unstable light emission can occur.
As described in the background art, when the emission energy of the laser is reduced to a certain extent, the stability, consistency, temperature drift characteristics and the like of the emission power are significantly deteriorated. To avoid this problem, in the embodiment of the present invention, the threshold light intensity of the laser may be determined, where the threshold light intensity is greater than the lower limit light intensity that the laser may emit, that is, if the laser emits light with an emission light intensity that is not less than the threshold light intensity, the stability, consistency, or temperature drift characteristic will not deteriorate.
To reduce this degradation to avoid affecting radar ranging, as an alternative example, a relationship of a threshold light intensity of the laser to the first and second light intensities may be compared, and if the threshold light intensity of the laser is between the first and second light intensities, it is determined that the light intensity of the laser at (n+1) -th detection of the transmitted signal adopts the threshold light intensity; otherwise, as an alternative example, a closer one of the first light intensity and the second light intensity than the threshold light intensity may be selected as the light intensity of the detection signal to be emitted next by the laser. Therefore, the laser can be reduced to emit light with small light intensity, the stability and consistency of the laser are improved, and the radar detection stability is improved.
In order for those skilled in the art to better understand and practice the transmit energy modulation method illustrated in fig. 2, a specific embodiment of the present invention is described below in terms of the following description.
In some embodiments of the present invention, for step S01, the core approach is to preset a range of expected echo intensities, i.e., to determine two echo intensity thresholds, i.e., a first intensityAnd a second intensity->The two echo intensity thresholds may be the upper and lower limits of the range of the probe in which the probe is at the preferred efficiency threshold, in other words, from the perspective of the probe, the range of the intensity of the echo signal corresponding to the preferred working range (which may be simply referred to as the echo intensity range) is determined
When the echo intensity received by the detector is between the first intensity and the second intensity, the photoelectric efficiency of the detector is greater than a preset threshold, for example, greater than 60%, 75% or 90%, or the like, or may be other values, and the specific threshold of the efficiency may be determined according to needs, which is not limited in the present application. For example, if the same 100 photons are incident on the detector, the detector may respond to 60 photons if at 60% efficiency, thereby outputting an electrical signal proportional to 60 photons; if at 75% efficiency, the detector may respond to 75 photons, thereby outputting an electrical signal proportional to 75 photons; if at 90% efficiency, the detector may respond to 90 photons, thereby outputting an electrical signal proportional to 90 photons.
When the echo signal intensity range of the detector with better photoelectric efficiency is determined in step S01, in order to comprehensively consider the factors at the receiving and transmitting ends of the laser radar, the emission light intensity range matched with the laser can be obtained through the echo signal intensity range relative to the detector. For example, a smaller one of the first emission light intensity of the laser and the upper limit light intensity of the laser calculated by using the first intensity may be selected, and then the selected smaller one is compared with a larger one of the lower limit light intensity of the laser to be used as the first light intensity; and selecting the larger one of the second emission light intensity of the laser obtained by calculation by adopting the second intensity and the lower limit light intensity of the laser, and comparing the selected larger one with the smaller one of the upper limit light intensity of the laser to obtain the second light intensity.
Specifically, first, the first intensity may be calculatedThe corresponding emitted light intensity is set as the first light intensitySecond intensity->The corresponding emitted light intensity is set to be the second light intensity +.>As previously described, there is a correspondence between the laser and the detector, and in order to allow the respective constraints of the laser and the detector to be matched, the same unit may be scaled, where the emitted light intensity of the laser may be scaled, where as an alternative example:
Wherein,the receiving intensity adopted in the detector is +.>In the case of (a), according to the corresponding relation between the current emitted light intensity of the laser and the current received echo intensity of the detector, namely(the physical meaning is that the nth and the (n+1) th can detect the same obstacle at the same distance, so that the ratio of the transmitting end to the receiving end at the nth and the (n+1) th is the same), and the value of the next emission light intensity corresponding to the theoretically expected laser is directly calculated, so that the first emission light intensity can be called for convenience of description;is the upper limit light intensity that the laser can emit; />Is the lower limit light intensity that the laser can emit.
In the laser radar field, since the frame frequency of the point cloud is high and the laser radar is expected to detect a longer distance, the laser is required to emit light with a relatively larger light intensity multiple times within a period of time, where the upper limit light intensity may be the maximum light intensity that the laser can emit, or may be slightly less than the maximum light intensity, such as 90% of the maximum light intensity, which is not limited herein, and only needs to be greater than the threshold light intensity.
Similarly, the lower limit light intensity that the laser can emit is a value greater than zero, and is not necessarily the minimum value of the physical limit that the laser can emit light, and if the laser emits light with an intensity less than a certain value for a period of time, the light emission stability, consistency or temperature drift characteristic deterioration occurs, this intensity value is the lower limit light intensity.
In addition, the time is not less than that of the laser for one-time lighting and meets the outside of the range limit of the laser radarThe obstacle of the boundary is reflected back, and the time spent by the corresponding detector is received, namely the time spent by the detection channel where the laser is located to finish one distance measurement. For step S02, a threshold light intensity of a laser is setWherein,in specific implementation, the lower limit value of the light intensity interval with stable light emitting performance of the laser can be selected as the threshold light intensity +.>
As described above, the light intensity with excellent light emission efficiency or operation state also exists for the laser, that is, if the laser emits light with an intensity greater than a certain intensity for a period of time, there is no deterioration in stability, uniformity or temperature drift characteristics, and this intensity value may be the threshold light intensity. At the same time, the emission light intensity of the laser has a constraint range, wherein, by the formula 1), the emission light intensity can be ensuredUpper limit light intensity emitted at the laser +.>And lower limit light intensity->Between them.
Correspondingly, the lower threshold value of the expected next luminous intensity of the laser, namely the second luminous intensity, can be calculated
Wherein,the (n+1) th time of the detector is adopted, the receiving intensity is +. >According to the corresponding relation between the nth emission light intensity of the laser and the echo intensity of the detector, namely +.>The value of the emission light intensity corresponding to the theoretically expected laser obtained through direct calculation can be called as second emission light intensity for convenience of description; />Is the upper limit light intensity that the laser can emit; />Is the lower limit light intensity that the laser can emit.
Similarly, the emitted light intensity of the laser has a constraint range, wherein, by the formula 2), it can be ensured thatUpper limit light intensity emitted at the laser +.>And lower limit light intensity->Between them.
Further, when the intensity values corresponding to the respective preferred working states of the detector and the laser are determined and converted to the emitted light intensity of the laser, the first light intensity, the second light intensity and the threshold light intensity can be comprehensively comparedThe final decision radar is based on the emitted light intensity of the laser used in the (n+1) th detection.
In particular, the first light intensity may be adjustedAnd said second light intensity->With threshold light intensity of the laserComparing if the threshold light intensity of the laser is +.>Between said first light intensity->And said second light intensity->And then determining the light intensity of the detection signal emitted next time by the laser >For the threshold light intensity +.>
Otherwise, the first light intensity may be selectedAnd said second light intensity->Of which the two are separated from the threshold light intensity +.>Light that is relatively closer in valueIntensity of the signal emitted by the laser in the (n+1) -th detection is determined as +.>This selection method can be expressed by the following formula:
the light intensity adjusting scheme in the embodiment of the invention also takes into account the stable operation of the laser and the power consumption factor of the whole radar, namely, the power consumption of the radar system is reduced while the stable light emission of the laser is ensured. In particular, for lidar, on the one hand the emitted light intensity of the laser is expected to be greater than the threshold light intensityThereby improving the stability and uniformity of the luminescence, so that in a specific implementation the threshold light intensity +.>The value of (2) can be the lower limit value of the light intensity interval in which the laser keeps the stable light emitting performance in one ranging. On the other hand, for the laser radar complete machine system provided with the laser, in order to further save electricity and power consumption, the laser can be expected to detect with smaller light intensity on the premise of meeting detection performance.
In the course of the specific implementation of this embodiment,can consider the factors of the luminescence stability of the laser, in The two take larger values; second, go up>Calculation of the minimum valueIs a factor of reducing power consumption of the laser radar as a whole, at +.>Both of which are smaller.
In this way, in combination with the above light intensity selection step, the scheme of the embodiment of the invention is that when the light intensity adopted by the laser radar in the (n+1) th detection is determined, the working efficiency of the detector and the laser is comprehensively considered, so that the detector is ensured to be in a better photoelectric efficiency, the light emitting scene of the laser with smaller light intensity is reduced, the stability and consistency of light emission are ensured, and meanwhile, the use of higher light intensity is avoided to save the power consumption of the radar, thereby improving the overall detection efficiency of the laser radar.
For a more visual understanding of the method of selecting the light intensity corresponding to equation 3), reference may be made to fig. 3A to 3C, which show schematic diagrams of possible values of the light intensity of the detection signal emitted by the laser, from which it can be seenAnd (3) withDifferent relative magnitude relations, wherein, in the emitted light intensity +.>The performance of the laser is good, namely the stability and consistency of luminescence are good; while at the emission intensity +.>In this case, the laser performance is lowered, and for example, stability and uniformity of light emission and a decrease in temperature drift characteristics may occur.
According to the above formula 3), the light intensity of the detection signal emitted next time by the laser under the corresponding conditions of 3A to 3C can be obtainedIs a value of (a).
Specifically, referring first to fig. 3A, wherein,that is to say,not located at->And->In the detection of the nth time, the echo intensity of the echo signal received by the radar detector is pre-pushed, when the (n+1) th time is detected, the laser and the detector cannot be simultaneously in the respective better working states, namely, the photoelectric efficiency of the detector is preferentially considered to improve the detection accuracy according to the formula 3), so that the light intensity of the detection signal emitted by the laser is improved when the laser radar performs the (n+1) th time detection>Taking outMiddle->More recent values, i.e. take +.>Light intensity as the next light emission +.>
Referring next to fig. 3B, wherein,i.e. < ->Is positioned at->And->In the detection of the nth time, the echo intensity of the echo signal received by the radar detector is pre-pushed, and when the (n+1) th time is detected, the laser and the detector are simultaneously in the respective better working states, so that the light intensity of the detection signal emitted by the laser next time is less than>Get->Thus the overall detection efficiency of the radar can be greatly improved.
Referring finally to fig. 3C, wherein,i.e. < ->Is not located atAnd->Between, and->And->Are all greater than->This is indicated byAccording to the nth detection, the echo intensity of the echo signal received by the radar detector is pre-pushed by only selecting +.>And->Any value in the range is used as the light intensity detected in the (n+1) th detection, the laser can stably emit light, the photoelectric efficiency of the detector is larger than a preset value, and the detector is in a preferred state, so that the power consumption of the radar is considered, namely the power consumption of the radar is reduced as much as possible on the premise of ensuring the detection performance of the radar, the light intensity of a detection signal emitted by the laser can be according to a formula 3) when the (n+1) th detection is carried outGet-> The two are separated from each other>A closer value, then->Get->
In order to more clearly show the relationship between the above parameters and the effect of the light intensity selection scheme according to the embodiment of the present invention, fig. 4 is a schematic diagram showing the relationship between the curves of the lidar emission energy adjustment method according to the embodiment of the present invention, including two sub-graphs of fig. 4 a) and fig. 4 b). In particular, the two sub-graphs of fig. 4 a) and 4 b) lie on a common horizontal axis(in the nth detection of the radar, the echo intensities of the echo signals received by the detector correspond to each other, that is, the horizontal axes of the two figures are the same.
In FIG. 4 a), the longitudinal axis of the laser radar (at the transmitting end, also denoted as TX) is the light intensity of the probe signal to be transmitted when the n+1th measurement is takenThe straight line shows the echo intensity of the current (i.e. nth) receipt of the probe +.>And the intensity of light emitted next (i.e. n+1th time) by the laser +.>Is a relationship of (3).
In FIG. 4 b), the vertical axis is the (n+1) th measurement, the intensity of the echo signal received by the detector of the laser radar (at the receiving end, also denoted as RX end)The straight line shows the echo intensity of the current (i.e. nth) receipt of the probe +.>And the echo intensity of the next (i.e. n+1th) reception by the detector +.>For any one laser, its luminous intensity has upper and lower limits, which may be maximum and minimum.
In the case of figure 4 a) of the drawings,indicating the upper limit light intensity that a certain laser can emit,/->Indicating the lower limit light intensity that a certain laser can emit. For any detector, the operating efficiency is high when the received signal strength is at a certain value, i.e. above a preset value, such as above 75%.
In FIG. 4 b), use is made ofRepresenting the corresponding lower limit of the echo intensity when the detector efficiency is high,/- >Representing the corresponding upper limit of echo intensity when the detector efficiency is high, and at the same time +.>It is also the range of intensities of echoes that the detector receives at the next radar detection. />The echo intensities expected to be received by the detector in the (n+1) th detection using prior art schemes are shown in FIG. 4 b) and can be understood as +.>
In addition, the solid line represents the relation among the parameters when the prior art scheme is adopted; the dashed lines correspond to the relationships between the above parameters when the embodiments of the present invention are adopted.
In order to more clearly explain the reason why the relationship among the 3 factors of the echo intensity of the echo signal received by the radar at the nth (i.e. when the probe is detected), the emission intensity of the laser at the (n+1) th (i.e. when the probe is detected) and the echo intensity of the echo signal received by the (n+1) th (i.e. when the probe is detected) is shown in fig. 4 a) and 4 b), the drawing is divided into five sections according to the magnitude of the echo intensity received by the probe, and further, in different sections, different linkage correspondence relationships exist among the above factors.
Specifically:
at the position ofSegments, possibly because of the extremely small reflectivity R of external obstacles, such as low reflection areas; or because the external obstacle is far away from the radar, when the (n+1) th scanning is performed, the laser emits light even if the laser directly adopts the maximum light intensity, and the corresponding (n+1) th echo signal receiving intensity still does not reach the expected target intensity value >When the TX-side laser maintains the upper limit light intensity, the intensity of the echo signal received by the detector at the time (n-th time) is continuously increased, which indicates that the reflectivity R of the obstacle is possibly increased and/or the distance between the obstacle and the radar is reduced until the reflectivity R of the obstacle is increased to a certain value and/or the distance between the obstacle and the radar is reduced to a certain value, at the moment, the first inflection point P1 is reached, and the intensity of the echo signal received by the detector at the time of (n+1) -th scanning reaches the target intensity value%>Also is
At the position ofThe section, the luminous intensity of the laser is from +.>Starts to gradually decrease and becomes smaller, and the receiving intensity of the echo signal corresponding to the moment is maintained to be the expected target intensity value +.>This indicates the reflectivity R of the external obstacle and/or the distance to the radarThe relation of separation is moderate. Thus, by adjusting the emitted light intensity of the laser at the TX end, the echo intensity of the echo signal at the RX end can be always maintained at the target intensity value +.>I.e. < ->In other words, the intensity of the echo signal received at the next detection is equal to the expected intensity. Meanwhile, referring to FIG. 4 a), the pulse intensity emitted from the laser is not less than +.>No deterioration of stability and consistency occurs.
At the position ofIn the paragraph, reference is made to the solid lines in fig. 4 a) and 4 b), which shows that if the prior art solution is adopted, in order to continue to maintain the detector still at the target intensity value +.>The intensity of the light emitted by the laser is reduced until +.>And is always maintained at +.>In this way, in this section, the laser emits light due to too small light intensity, so that problems such as stability, consistency and abnormal temperature drift characteristics occur, and the accuracy of radar detection is reduced.
With reference to the dashed lines in fig. 4 a) and 4 b), the laser may then be maintained using the scheme of the present embodimentIs luminous up to->Is not slowly decreased until +.>Only decrease to->As can be seen from comparing the adjustment results of the prior art scheme shown by the solid line, the lower limit light intensity of the laser is +.>The use interval of the laser can be obviously shortened, and the lower limit light intensity is only used in the interval after the reflectivity is larger than P5, so that the scene of the deterioration of the working state of the laser is greatly reduced. At the same time->The radar predicts the (n+1) th detection, and the echo intensity of the echo signal received by the detector is always maintained at +. >Indicating that the photoelectric efficiency of the detector is relatively high and thus the overall detection efficiency of the radar is high.
At the position ofThe section, along with the integral rising trend of the received echo signal intensity in the nth scanning, the light intensity of the transmitting end laser remains unchanged, even if the TX end laser already adopts the lower limit light intensity in the (n+1) th scanning>Emits light, and the echo intensity of the echo signal received in the (n+1) th scanning exceeds the target intensity valueIndicating that the reflectivity of the external obstacle is increasing and/or that the distance between the obstacle and the radar is shrinking.
From the above, by adopting the embodiment of the invention, the use range of the lower limit light intensity of the laser can be reduced (fromReduced to->) The laser radar has the advantages that larger emission light intensity, such as the threshold light intensity of the laser, is used in as many detection scenes as possible, so that the stability and consistency of the light emission of the laser in the medium-high reflectivity detection scenes can be improved, and the measurement accuracy and accuracy of the laser radar to the target with the medium-high reflectivity can be improved.
In addition, as the lower limit light intensity is only used when the obstacle with extremely high reflectivity is adopted, such as a guideboard made of a corner reflector, for the objects, the echo signal is extremely strong, the reflectivity is saturated, so that the precision and the accuracy of specific numerical values of measurement can be ignored, and at the moment, the problem of poor stability, consistency and temperature drift characteristics when the laser works under the lower limit light intensity can not greatly influence the measurement result of the laser radar.
Thus, in an implementation, the lower limit light intensity of the laser may be further reducedThe strength of the echo signal of the object with extremely high reflectivity is reduced, the crosstalk characteristic of the laser radar can be improved, and the measurement performance of the laser radar is further improved. For example, the small light intensity of the laser may be set such that the intensity of the received echo signal is still less than a preset receive intensity threshold when the detector detects that the reflectivity exceeds a preset reflectivity threshold (corresponding to an extremely high reflectivity object).
In order to implement the method for adjusting the emission energy according to the embodiment, the embodiment of the invention further provides a corresponding system for adjusting the emission energy of the laser radar, wherein the laser radar comprises a laser and a detector, and the method comprises the following steps: the laser is adapted to emit a detection signal, and the detector is adapted to receive an echo signal of the detection signal after reflection by an obstacle. In an embodiment of the present invention, referring to fig. 5, an emission energy adjustment system 50 may include: an emission light intensity calculation unit 51 and an emission light intensity determination unit 52, wherein:
the emitted light intensity calculating unit 51 is adapted to calculate the light intensity of the next light emission of the corresponding laser according to the intensity of the echo signal preset received by the detector;
The emitted light intensity determining unit 52 is adapted to compare the calculated light intensity with a threshold light intensity of the laser, and to determine the light intensity of the detection signal emitted next time by the laser based on the comparison result, the threshold light intensity of the laser being higher than the lower limit light intensity of the laser.
In a specific implementation, when the intensity of the echo signal is the preset intensity of the echo signal, the detection efficiency of the detector is greater than a preset efficiency threshold.
In a specific implementation, the specific implementation and principles of the emission energy adjustment system may be described with reference to the foregoing embodiments, where the emission energy adjustment system may be obtained by a processor through program running operation.
The embodiment of the present invention further provides a corresponding lidar, referring to the structural schematic diagram of the lidar shown in fig. 6, the lidar 60 includes a laser 61, a detector 62 and a processor 63, where:
the laser 61 is adapted to emit a detection signal;
the detector 62 is adapted to receive an echo signal of the detected signal after being reflected by an obstacle;
the processor 63 is adapted to calculate the light intensity of the corresponding laser 61 when emitting light next time according to the preset intensity of the echo signal received by the preset detector 62; and comparing the calculated light intensity with a threshold light intensity of the laser 61, and determining the light intensity of the detection signal emitted next time by the laser 61 based on the comparison result, wherein the threshold light intensity of the laser 61 is higher than the lower limit light intensity of the laser 61.
To complete the nth ranging, referring to fig. 6, under the control of the processor 63, the laser 61 may emit a detection signal with a certain intensity (i.e., the intensity of the next light emission), and if an obstacle is encountered within the range of the ranging limit, the detection signal is reflected by the obstacle, and a part of the detection signal returns to the lidar, the detection signal may be received by the detector 62 as an echo signal, and the intensity of the echo signal is the intensity of the echo signal received for the nth time. The processor 63 then reads the signal output from the detector 62 and performs further processing, such as amplification, filtering, peak calculation, etc., to obtain the distance and reflectivity information of the obstacle, which may be used as a result of the laser radar detection at the nth time.
In order to improve the ranging accuracy and efficiency of the radar during the (n+1) th detection, the processor 63 may calculate the intensity of the corresponding laser 61 when emitting light next according to the preset intensity of the echo signal received next by the detector 62, compare the calculated intensity with the threshold intensity of the laser 61, and finally determine the intensity of the detection signal emitted next by the laser 61 based on the comparison result.
The processor 63 may then control the laser 61 to emit light in accordance with the determined intensity of light emitted next time for the next ranging. Specifically, the laser 61 may further retransmit a detection signal according to the determined light intensity, and then the detector 62 may receive an echo signal after the retransmitted detection signal is reflected by an obstacle, and accordingly, the processor may process the received echo signal again to obtain the distance and reflectivity information of the obstacle as a detection result of the (n+1) th time.
In summary, by adopting the laser radar, the light intensity of the detection signal emitted by the laser can meet the performance requirements of the detector and the laser, so that the scene of the laser regulated to the lower limit light intensity is greatly reduced, the problem of unstable light emission of the laser caused by the use of the lower limit light intensity to emit the detection signal can be avoided in a plurality of scenes, the accuracy of measuring the distance and the reflectivity of the laser radar in the scenes can be improved, and the overall measuring accuracy of the laser radar can be effectively improved.
In a specific implementation, the processor 63 is adapted to determine that the intensity of the preset received echo signal is between a first intensity and a second intensity, where the first intensity is greater than the second intensity, and calculate the light intensity of the corresponding laser 61 when emitting light next time according to the first intensity, the second intensity, the light emitting intensity of the laser 61 next time, and the intensity of the echo received by the detector 62 next time, respectively.
As an alternative example, the processor 63 is adapted to calculate the first emission intensity of the corresponding laser 61 according to the first intensity, the current emission intensity of the laser 61 and the current intensity of the echo received by the detector 62; calculating a second emission light intensity of the corresponding laser 61 according to the second intensity, the current luminous intensity of the laser 61 and the current intensity of the echo received by the detector 62; the first light intensity and the second light intensity are calculated according to the relation between the first emission light intensity of the laser 61 calculated by the first intensity, the second emission light intensity of the laser 61 calculated by the second intensity, and the upper limit light intensity and the lower limit light intensity of the laser 61.
As an alternative example, the processor 63 is adapted to select the smaller of the first emission intensity of the laser calculated by using the first intensity and the upper limit intensity of the laser 61, and then compare the selected smaller with the larger of the lower limit intensities of the laser 61 as the first intensity; and selecting the larger one of the second emission light intensity of the laser 61 and the lower limit light intensity of the laser 61 obtained by calculation using the second intensity, and comparing the selected larger one with the smaller one of the upper limit light intensity of the laser 61 to obtain the second light intensity.
In a specific implementation, the processor 63 is adapted to compare a threshold light intensity of the laser 61 with the first light intensity and the second light intensity; and if the threshold light intensity of the laser 61 is between the first light intensity and the second light intensity, determining that the light intensity of the detection signal emitted by the laser 61 next time is the threshold light intensity; otherwise, the one of the first light intensity and the second light intensity that is closer to the threshold light intensity is selected as the light intensity of the detection signal emitted next by the laser 61.
In a specific implementation, with continued reference to fig. 6, the processor 63 is further adapted to set the lower limit light intensity of the laser 61, so that the intensity of the echo signal received by the detector 62 when the reflectivity is detected to exceed the preset reflectivity threshold is still smaller than the preset receiving intensity threshold, and by setting the lower limit light intensity of the laser 61 to meet the above condition, crosstalk can be reduced, and the detection performance of the laser radar 60 is further improved.
The specific adjustment scheme, principle, effect and the like of the emission energy of the laser radar in the embodiment of the invention can be described with reference to the previous embodiment.
It should be noted that, in the embodiment of the present invention, the emitted light intensity of the laser and the echo signal intensity of the detector are used to represent the emitted energy and the received energy respectively, and in the specific implementation, power, energy or other physical parameters capable of representing the energy or physical parameters having a corresponding relationship with the energy characteristics may be used, which are all within the protection scope of the present invention.
Although the embodiments of the present specification are disclosed above, the present specification is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention is therefore intended to be limited only by the appended claims.

Claims (16)

1. A method of adjusting the transmitted energy of a lidar, the method comprising:
according to the intensity of the echo signal preset and received by the detector, calculating the light intensity of the corresponding laser which emits light next time;
and comparing the calculated light intensity with the threshold light intensity of the laser, and determining the light intensity of the detection signal emitted next time by the laser based on the comparison result, wherein the threshold light intensity of the laser is higher than the lower limit light intensity of the laser.
2. The method of claim 1, wherein the detection efficiency of the detector is greater than a preset efficiency threshold when the intensity of the echo signal received by the detector is within the preset intensity of the echo signal received.
3. The method according to claim 1, wherein calculating the intensity of the next light emission of the corresponding laser according to the intensity of the echo signal preset by the detector comprises:
Determining that the intensity of the preset received echo signal is between a first intensity and a second intensity, wherein the first intensity is larger than the second intensity;
and calculating the light intensity of the next light emission of the corresponding laser according to the first intensity, the second intensity, the current light emission intensity of the laser and the current received echo signal intensity of the detector.
4. A method according to claim 3, wherein calculating the intensity of the next light emission of the corresponding laser according to the first intensity, the second intensity, the current light emission intensity of the laser, and the current intensity of the echo received by the detector, respectively, comprises:
calculating the first emission light intensity of the corresponding laser according to the first intensity, the current luminous intensity of the laser and the current intensity of the echo signal received by the detector;
calculating second emission light intensity of the corresponding laser according to the second intensity, the current luminous intensity of the laser and the current intensity of the echo signal received by the detector;
according to the relation among the first emission light intensity of the laser obtained by calculation of the first intensity, the second emission light intensity of the laser obtained by calculation of the second intensity, the upper limit light intensity and the lower limit light intensity of the laser, the first light intensity and the second light intensity are obtained by calculation respectively, the first light intensity is higher than the second light intensity, and the first emission light intensity and the second emission light intensity are both located between the first light intensity and the second light intensity.
5. The method of claim 4, wherein calculating the first light intensity and the second light intensity based on a relationship between the first emission light intensity of the laser calculated using the first intensity, the second emission light intensity of the laser calculated using the second intensity, and the upper limit light intensity and the lower limit light intensity of the laser, respectively, comprises:
selecting the smaller one of the first emission light intensity of the laser obtained by calculation by adopting the first intensity and the upper limit light intensity of the laser, and then comparing the selected smaller one with the larger one of the lower limit light intensity of the laser to obtain the first light intensity;
and selecting the larger one of the second emission light intensity of the laser obtained by calculation by adopting the second intensity and the lower limit light intensity of the laser, and comparing the selected larger one with the smaller one of the upper limit light intensity of the laser to obtain the second light intensity.
6. The method according to claim 4 or 5, wherein comparing the calculated emitted light intensity with a threshold light intensity of the laser, and determining the light intensity of the detection signal emitted next by the laser based on the comparison result, comprises:
comparing the relation between the threshold light intensity of the laser and the first light intensity and the second light intensity;
And if the threshold light intensity of the laser is between the first light intensity and the second light intensity, determining the light intensity of the detection signal transmitted by the laser next time as the threshold light intensity.
7. The method as recited in claim 6, further comprising:
if the threshold light intensity of the laser is not between the first light intensity and the second light intensity, selecting the light intensity of the detection signal emitted by the laser next time as the light intensity of the detection signal which is closer to the threshold light intensity in the first light intensity and the second light intensity.
8. The method of claim 7, wherein the selecting the closer of the first light intensity and the second light intensity to the threshold light intensity as the light intensity of the detection signal emitted next by the laser comprises:
and selecting the larger one of the threshold light intensity and the second light intensity, and comparing the selected larger one with the smaller one of the first light intensity to be used as the light intensity of the detection signal emitted by the laser next time.
9. The method as recited in claim 1, further comprising:
and setting the lower limit light intensity of the laser, so that the intensity of the received echo signal is smaller than a preset receiving intensity threshold when the detector detects that the reflectivity exceeds the preset reflectivity threshold.
10. A transmit energy adjustment system for a lidar, comprising:
the emitted light intensity calculating unit is suitable for calculating the light intensity of the corresponding laser which emits light next time according to the preset intensity of the received echo signal of the detector; and the emitted light intensity determining unit is suitable for comparing the calculated light intensity with the threshold light intensity of the laser, and determining the light intensity of the detection signal emitted next time by the laser based on the comparison result, wherein the threshold light intensity of the laser is higher than the lower limit light intensity of the laser.
11. A lidar, comprising:
a laser adapted to emit a detection signal;
the detector is suitable for receiving echo signals of the detection signals reflected by the obstacle;
the processor is suitable for presetting the intensity of the received echo signal according to the preset detector and calculating the light intensity of the corresponding laser emitted next time; and comparing the calculated light intensity with the threshold light intensity of the laser, and determining the light intensity of the detection signal emitted next time by the laser based on the comparison result, wherein the threshold light intensity of the laser is greater than the lower limit light intensity of the laser.
12. The lidar of claim 11, wherein the detection efficiency of the detector is greater than a preset efficiency threshold when the intensity of the echo signal received by the detector is within the preset intensity of the received echo signal.
13. The lidar according to claim 11, wherein the processor is adapted to determine that the intensity of the preset received echo signal is between a first intensity and a second intensity, and that the first intensity is greater than the second intensity, and to calculate the intensity of the next light emission of the corresponding laser based on the first intensity, the second intensity, the intensity of the current light emission of the laser, and the intensity of the echo received by the detector, respectively.
14. The lidar of claim 13, wherein the processor is adapted to calculate a first intensity of the corresponding laser based on the first intensity, the current intensity of the laser light, and the current intensity of the echo received by the detector; calculating second emission light intensity of the corresponding laser according to the second intensity, the current luminous intensity of the laser and the current intensity of the echo received by the detector; and respectively calculating the first light intensity and the second light intensity according to the relation among the first emission light intensity of the laser obtained by calculating the first intensity, the second emission light intensity of the laser obtained by calculating the second intensity and the upper limit light intensity and the lower limit light intensity of the laser.
15. The lidar of claim 14, wherein the processor is adapted to select a smaller of the first intensity of the laser and an upper intensity of the laser calculated using the first intensity, and then compare the selected smaller with a larger of a lower intensity of the laser as the first intensity; and selecting the larger one of the second emission light intensity of the laser obtained by calculation by adopting the second intensity and the lower limit light intensity of the laser, and comparing the selected larger one with the smaller one of the upper limit light intensity of the laser to obtain the second light intensity.
16. The lidar according to claim 14 or 15, wherein the processor is adapted to compare a threshold light intensity of the laser to the first light intensity and the second light intensity; if the threshold light intensity of the laser is between the first light intensity and the second light intensity, determining the light intensity of the detection signal emitted by the laser next time as the threshold light intensity; otherwise, selecting the light intensity of the detection signal emitted by the laser next time as the light intensity of the detection signal which is closer to the threshold light intensity in the first light intensity and the second light intensity.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5163063A (en) * 1990-02-07 1992-11-10 Copal Co., Ltd. Semiconductor laser driving circuit
CN102761053A (en) * 2011-04-26 2012-10-31 厦门优迅高速芯片有限公司 Automatic power control method and device of laser
EP3516415B1 (en) * 2016-09-22 2024-12-04 Apple Inc. Adaptive transmission power control for a lidar
CN109870678B (en) * 2018-12-06 2024-02-20 苏州镭图光电科技有限公司 Laser radar transmitting power and echo gain automatic adjusting method and adjusting device
CN111551951B (en) * 2020-06-18 2024-11-15 北京微厘光电技术有限公司 A laser Doppler velocimeter with automatic signal size adjustment and its signal size control strategy
CN112764049A (en) * 2021-01-29 2021-05-07 深圳清华大学研究院 Laser ranging device and signal adjusting method and signal adjusting circuit thereof

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