WO2020220275A1 - Circuit de détection, procédé de détection, appareil de télémétrie et plateforme mobile - Google Patents

Circuit de détection, procédé de détection, appareil de télémétrie et plateforme mobile Download PDF

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Publication number
WO2020220275A1
WO2020220275A1 PCT/CN2019/085221 CN2019085221W WO2020220275A1 WO 2020220275 A1 WO2020220275 A1 WO 2020220275A1 CN 2019085221 W CN2019085221 W CN 2019085221W WO 2020220275 A1 WO2020220275 A1 WO 2020220275A1
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WIPO (PCT)
Prior art keywords
threshold
pulse signal
time information
noise
electrical pulse
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PCT/CN2019/085221
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English (en)
Chinese (zh)
Inventor
陈涵
梅雄泽
龙承辉
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深圳市大疆创新科技有限公司
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Application filed by 深圳市大疆创新科技有限公司 filed Critical 深圳市大疆创新科技有限公司
Priority to PCT/CN2019/085221 priority Critical patent/WO2020220275A1/fr
Priority to CN201980008851.1A priority patent/CN112236687A/zh
Publication of WO2020220275A1 publication Critical patent/WO2020220275A1/fr

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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
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves

Definitions

  • the invention relates to the technical field of laser radar, in particular to a detection circuit, a detection method, a ranging device, and a mobile platform.
  • the laser ranging system is a perceptual sensor that can obtain three-dimensional information of the scene. Its basic principle is to actively emit a laser pulse signal to the detected object and obtain the reflected pulse signal, according to the time difference between the transmitted signal and the received signal Calculate the depth information of the distance detector of the measured object; obtain the angle information of the measured object relative to the laser ranging system based on the known emission direction of the laser ranging system; combine the aforementioned depth and angle information to obtain a large number of detection points (called Point cloud), based on the point cloud, the spatial three-dimensional information of the measured object relative to the laser ranging system can be reconstructed.
  • Point cloud detection points
  • a certain threshold is usually preset in the laser ranging system.
  • the threshold is triggered by the optical pulse signal to generate Corresponding trigger signal, the threshold is usually fixed, resulting in a mismatch of false alarm rate and range under different ambient light noise levels, which often increases the false alarm rate to an unacceptable level. Therefore, the above-mentioned problems existing at present are improved.
  • the first aspect of the present invention provides a detection circuit, which includes:
  • the comparing unit is used to receive the electrical pulse signal converted from the optical pulse signal and perform a comparison operation between the electrical pulse signal and a threshold value set, and collect time information corresponding to the electrical pulse signal, wherein the threshold value set
  • Each threshold is divided into multiple threshold groups in descending order, and each threshold group contains at least one threshold;
  • the judging unit is configured to filter out non-noise time information according to the minimum value in the threshold group triggered by the electrical pulse signal and the noise level;
  • the calculation unit is configured to calculate the pulse information of the electrical pulse signal according to the filtered time information.
  • the present invention also provides an optical signal detection method, including:
  • the electrical pulse signal is compared with a threshold value set, and time information corresponding to the electrical pulse signal is collected.
  • Each threshold value in the threshold value set is divided into multiple threshold value groups in ascending order. There is at least one threshold in each threshold group;
  • the pulse information of the electrical pulse signal is calculated according to the filtered time information.
  • the present invention also provides a distance measuring device, including:
  • Light emitting circuit used to emit light pulse signals
  • a light conversion circuit for receiving at least a part of the laser signal reflected by the object from the laser pulse signal emitted by the light emitting circuit, and converting the received laser signal into an electrical pulse signal;
  • the aforementioned detection circuit is used to sample the electrical signal from the laser receiving circuit to obtain pulse information of the electrical pulse signal;
  • the arithmetic circuit is used to calculate the distance between the object and the distance measuring device according to the pulse information.
  • the present invention also provides a mobile platform, including:
  • the platform body, the light emitting circuit of the distance measuring device is installed on the platform body.
  • the mobile platform includes at least one of an unmanned aerial vehicle, a car, and a robot.
  • the present invention provides the above-mentioned detection circuit, detection method, distance measuring device and mobile platform.
  • the detection circuit can dynamically abandon the low threshold grouping that does not meet the requirements according to the external light noise by grouping preset thresholds to ensure the lowest threshold Always above the noise amplitude, so as to optimize the lowest threshold of TDC so that under different ambient light noise levels, the laser ranging system can reach the widest detection range.
  • FIG. 1 is a schematic diagram of the structure of a sampling signal obtained by a time-to-digital conversion method in an embodiment of the prior art
  • FIG. 3 is a schematic diagram of the structure of the detection circuit for pulse division in an embodiment of the present invention.
  • FIG. 4 is a schematic frame diagram of a distance measuring device provided by an embodiment of the present invention.
  • Fig. 5 is a schematic diagram of an embodiment in which a distance measuring device provided by an embodiment of the present invention adopts a coaxial optical path.
  • the detection circuit provided by each embodiment of the present invention may be applied to a distance measuring device, and the distance measuring device may be electronic equipment such as laser radar and laser distance measuring equipment.
  • the distance measuring device is used to sense external environmental information, for example, distance information, orientation information, reflection intensity information, speed information, etc. of environmental targets.
  • the distance measuring device can detect the distance from the probe to the distance measuring device by measuring the time of light propagation between the distance measuring device and the probe, that is, the time-of-flight (TOF).
  • the ranging device can also detect the distance from the detected object to the ranging device through other technologies, such as a ranging method based on phase shift measurement, or a ranging method based on frequency shift measurement. There is no restriction.
  • the distance and azimuth detected by the ranging device can be used for remote sensing, obstacle avoidance, surveying and mapping, modeling, navigation, etc.
  • the distance measuring device of the embodiment of the present invention can be applied to a mobile platform, and the distance measuring device can be installed on the platform body of the mobile platform.
  • a mobile platform with a distance measuring device can measure the external environment, for example, measuring the distance between the mobile platform and obstacles for obstacle avoidance and other purposes, and for two-dimensional or three-dimensional mapping of the external environment.
  • the mobile platform includes at least one of an unmanned aerial vehicle, a car, a remote control car, a robot, and a camera.
  • the ranging device is applied to an unmanned aerial vehicle, the platform body is the fuselage of the unmanned aerial vehicle.
  • the platform body When the distance measuring device is applied to a car, the platform body is the body of the car.
  • the car can be a self-driving car or a semi-automatic driving car, and there is no restriction here.
  • the platform body When the distance measuring device is applied to a remote control car, the platform body is the body of the remote control car.
  • the platform body When the distance measuring device is applied to a robot, the platform body is a robot.
  • the distance measuring device When the distance measuring device is applied to a camera, the platform body is the camera itself.
  • the distance measuring device 100 may include a transmitting circuit 110, a receiving circuit 120, a detecting circuit 130, and an arithmetic circuit 140.
  • the transmitting circuit 110 may emit a light pulse sequence (for example, a laser pulse sequence).
  • the receiving circuit 120 can receive the light pulse sequence reflected by the object to be detected, and perform photoelectric conversion on the light pulse sequence to obtain an electrical signal. After processing the electrical signal, the electrical signal can be output to the detection circuit 130.
  • the detection circuit 130 may sample the electrical signal to obtain the sampling result.
  • the arithmetic circuit 140 may determine the distance between the distance measuring device 100 and the detected object based on the sampling result of the detection circuit 130.
  • the distance measuring device 100 may further include a control circuit 150, which can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.
  • a control circuit 150 can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.
  • the distance measuring device shown in FIG. 4 includes a transmitting circuit, a receiving circuit, a detection circuit, and an arithmetic circuit for emitting a beam for detection
  • the embodiment of the present application is not limited to this, the transmitting circuit
  • the number of any one of the receiving circuit, the detection circuit, and the arithmetic circuit can also be at least two, which are used to emit at least two light beams in the same direction or in different directions respectively; wherein, the at least two light paths can be simultaneous Shooting can also be shooting at different times.
  • the light-emitting chips in the at least two transmitting circuits are packaged in the same module.
  • each emitting circuit includes a laser emitting chip, and the dies in the laser emitting chips in the at least two emitting circuits are packaged together and housed in the same packaging space.
  • the distance measuring device 100 may further include a scanning module for changing the propagation direction of at least one laser pulse sequence emitted by the transmitting circuit.
  • the module including the transmitting circuit 110, the receiving circuit 120, the detection circuit 130, and the operation circuit 140, or the module including the transmitting circuit 110, the receiving circuit 120, the detection circuit 130, the operation circuit 140, and the control circuit 150 may be referred to as the measurement circuit.
  • the distance module the distance measurement module can be independent of other modules, for example, scanning module.
  • a coaxial optical path can be used in the distance measuring device, that is, the light beam emitted from the distance measuring device and the reflected light beam share at least part of the optical path in the distance measuring device.
  • the distance measuring device may also adopt an off-axis optical path, that is, the light beam emitted by the distance measuring device and the reflected light beam are respectively transmitted along different optical paths in the distance measuring device.
  • Fig. 5 shows a schematic diagram of an embodiment in which the distance measuring device of the present invention adopts a coaxial optical path.
  • the ranging device 200 includes a ranging module 210, which includes a transmitter 203 (which may include the above-mentioned transmitting circuit), a collimating element 204, a detector 205 (which may include the above-mentioned receiving circuit, detection circuit, and arithmetic circuit) and Light path changing element 206.
  • the ranging module 210 is used to emit a light beam, receive the return light, and convert the return light into an electrical signal.
  • the transmitter 203 can be used to emit a light pulse sequence.
  • the transmitter 203 may emit a sequence of laser pulses.
  • the laser beam emitted by the transmitter 203 is a narrow-bandwidth beam with a wavelength outside the visible light range.
  • the collimating element 204 is arranged on the exit light path of the emitter, and is used to collimate the light beam emitted from the emitter 203, and collimate the light beam emitted from the emitter 203 into parallel light and output to the scanning module.
  • the collimating element is also used to condense at least a part of the return light reflected by the probe.
  • the collimating element 204 may be a collimating lens or other elements capable of collimating light beams.
  • the transmitting light path and the receiving light path in the distance measuring device are combined before the collimating element 204 through the light path changing element 206, so that the transmitting light path and the receiving light path can share the same collimating element, so that the light path More compact.
  • the transmitter 203 and the detector 205 may respectively use their own collimating elements, and the optical path changing element 206 is arranged on the optical path behind the collimating element.
  • the light path changing element can use a small area mirror to The transmitting light path and the receiving light path are combined.
  • the light path changing element may also use a reflector with a through hole, where the through hole is used to transmit the emitted light of the emitter 203 and the reflector is used to reflect the return light to the detector 205. In this way, the shielding of the back light by the bracket of the small mirror in the case of using the small mirror can be reduced.
  • the optical path changing element deviates from the optical axis of the collimating element 204.
  • the optical path changing element may also be located on the optical axis of the collimating element 204.
  • the distance measuring device 200 further includes a scanning module 202.
  • the scanning module 202 is placed on the exit light path of the distance measuring module 210.
  • the scanning module 202 is used to change the transmission direction of the collimated beam 219 emitted by the collimating element 204 and project it to the external environment, and project the return light to the collimating element 204 .
  • the returned light is collected on the detector 205 via the collimating element 204.
  • the scanning module 202 may include at least one optical element for changing the propagation path of the light beam, wherein the optical element may change the propagation path of the light beam by reflecting, refracting, or diffracting the light beam.
  • the scanning module 202 includes a lens, a mirror, a prism, a galvanometer, a grating, a liquid crystal, an optical phased array (Optical Phased Array), or any combination of the foregoing optical elements.
  • at least part of the optical elements are moving.
  • a driving module is used to drive the at least part of the optical elements to move.
  • the moving optical elements can reflect, refract, or diffract the light beam to different directions at different times.
  • the multiple optical elements of the scanning module 202 may rotate or vibrate around a common axis 209, and each rotating or vibrating optical element is used to continuously change the propagation direction of the incident light beam.
  • the multiple optical elements of the scanning module 202 may rotate at different speeds or vibrate at different speeds.
  • at least part of the optical elements of the scanning module 202 may rotate at substantially the same rotation speed.
  • the multiple optical elements of the scanning module may also be rotated around different axes.
  • the multiple optical elements of the scanning module may also rotate in the same direction or in different directions; or vibrate in the same direction, or vibrate in different directions, which is not limited herein.
  • the scanning module 202 includes a first optical element 214 and a driver 216 connected to the first optical element 214.
  • the driver 216 is used to drive the first optical element 214 to rotate around the rotation axis 209 to change the first optical element 214.
  • the direction of the beam 219 is collimated.
  • the first optical element 214 projects the collimated light beam 219 to different directions.
  • the angle between the direction of the collimated beam 219 changed by the first optical element and the rotation axis 209 changes as the first optical element 214 rotates.
  • the first optical element 214 includes a pair of opposed non-parallel surfaces through which the collimated light beam 219 passes.
  • the first optical element 214 includes a prism whose thickness varies in at least one radial direction.
  • the first optical element 214 includes a wedge prism, and the collimated beam 219 is refracted.
  • the scanning module 202 further includes a second optical element 215, the second optical element 215 rotates around the rotation axis 209, and the rotation speed of the second optical element 215 is different from the rotation speed of the first optical element 214.
  • the second optical element 215 is used to change the direction of the light beam projected by the first optical element 214.
  • the second optical element 115 is connected to another driver 217, and the driver 217 drives the second optical element 215 to rotate.
  • the first optical element 214 and the second optical element 215 can be driven by the same or different drivers, so that the rotation speed and/or rotation of the first optical element 214 and the second optical element 215 are different, so as to project the collimated light beam 219 to the outside space Different directions can scan a larger space.
  • the controller 218 controls the drivers 216 and 217 to drive the first optical element 214 and the second optical element 215, respectively.
  • the rotational speeds of the first optical element 214 and the second optical element 215 may be determined according to the area and pattern expected to be scanned in actual applications.
  • the drivers 216 and 217 may include motors or other drivers.
  • the second optical element 215 includes a pair of opposite non-parallel surfaces through which the light beam passes. In one embodiment, the second optical element 215 includes a prism whose thickness varies in at least one radial direction. In one embodiment, the second optical element 215 includes a wedge prism.
  • the scanning module 202 further includes a third optical element (not shown) and a driver for driving the third optical element to move.
  • the third optical element includes a pair of opposite non-parallel surfaces, and the light beam passes through the pair of surfaces.
  • the third optical element includes a prism whose thickness varies in at least one radial direction.
  • the third optical element includes a wedge prism. At least two of the first, second, and third optical elements rotate at different rotation speeds and/or rotation directions.
  • each optical element in the scanning module 202 can project light to different directions, such as the direction of the projected light 211 and the direction 213, so that the space around the distance measuring device 200 is scanned.
  • the light 211 projected by the scanning module 202 hits the detection object 201, a part of the light is reflected by the detection object 201 to the distance measuring device 200 in a direction opposite to the projected light 211.
  • the return light 212 reflected by the probe 201 is incident on the collimating element 204 after passing through the scanning module 202.
  • the detector 205 and the transmitter 203 are placed on the same side of the collimating element 204, and the detector 205 is used to convert at least part of the return light passing through the collimating element 204 into an electrical signal.
  • an anti-reflection film is plated on each optical element.
  • the thickness of the antireflection coating is equal to or close to the wavelength of the light beam emitted by the emitter 203, which can increase the intensity of the transmitted light beam.
  • a filter layer is plated on the surface of an element located on the beam propagation path in the distance measuring device, or a filter is provided on the beam propagation path for transmitting at least the wavelength band of the beam emitted by the transmitter, Reflect other bands to reduce the noise caused by ambient light to the receiver.
  • the transmitter 203 may include a laser diode through which nanosecond laser pulses are emitted.
  • the laser pulse receiving time can be determined, for example, the laser pulse receiving time can be determined by detecting the rising edge time and/or the falling edge time of the electrical signal pulse. In this way, the distance measuring device 200 can calculate the TOF using the pulse receiving time information and the pulse sending time information, so as to determine the distance between the probe 201 and the distance measuring device 200.
  • the lowest threshold on the one hand determines the smallest pulse signal that can be detected, that is, determines the range of the laser ranging system, on the other hand, determines the probability of the detector's false detection of ambient light noise, that is, it determines The false alarm rate of the laser ranging system is improved.
  • the threshold used to detect the received pulse signal is usually fixed, resulting in a mismatch of false alarm rate and range under different ambient light noise levels.
  • the set threshold 1 is taken as the lowest threshold, an acceptable false alarm rate and range can be obtained in the darkroom environment, but under the sun (the noise level is several times or even ten times that of the darkroom) This increases the false alarm rate to an unacceptable level. Therefore, the set threshold 3 is fixed as the lowest threshold to ensure the false alarm rate and range under the sun, at this time the range of the darkroom will be sacrificed.
  • the present invention provides a detection circuit. It can be understood that the detection circuit provided by the present invention is not limited to the ranging system described above, and can also be used in ranging systems with other structures or other functions, or in other applications with the same problems or the same requirements. In the system, there is no restriction here.
  • the detection circuit includes:
  • the comparing unit is configured to receive the electrical pulse signal converted from the optical pulse signal and perform a comparison operation between the electrical pulse signal and a threshold value set, and collect time information corresponding to the electrical pulse signal, wherein, in the threshold value set
  • Each threshold is divided into multiple threshold groups in ascending order, and each threshold group contains at least one threshold;
  • the judging unit is configured to filter out non-noise time information according to the minimum value in the threshold group triggered by the electrical pulse signal and the noise level;
  • the calculation unit is configured to calculate the pulse information of the electrical pulse signal according to the filtered time information.
  • the comparison unit includes a plurality of time-to-digital converters (Time-to-Digital Converter, TDC), and the plurality of TDCs respectively have different thresholds;
  • TDC Time-to-Digital Converter
  • the TDC is used to output trigger time information when the received electrical pulse signal triggers a corresponding threshold.
  • the number of time information corresponding to the electrical pulse signals collected by the comparison unit is 0-2N.
  • the comparison unit can collect N time information, and the electrical pulse signal can trigger all thresholds and collect the rising edge information and the falling edge information.
  • edge information the comparison unit can collect 2N time information.
  • the time information collected by the comparison unit is not necessarily all triggered by electrical pulse signals, and may also be triggered by noise signals. Therefore, the number of time information output by the comparison unit may be greater than 2N, even in When the number is less than 2N, there may also be time information triggered by noise signals.
  • the judgment unit filters out the non-noise time information from all the time information collected by the comparison unit, and calculates the electrical pulse based on the filtered time information and the corresponding trigger threshold.
  • the pulse information of the signal For example, at least one of the waveform, amplitude, and spread of the electrical pulse signal is calculated.
  • multiple different thresholds are set within the dynamic range of the received pulse signal in the comparison unit.
  • 12 thresholds are set in the comparison unit, namely T1, T2,..., T12, and the size of the preset thresholds is T1 ⁇ T2 ⁇ ... ⁇ T12, as shown in Figure 3.
  • each preset threshold in the threshold set is divided into at least two threshold groups in descending order, and each threshold group includes at least one threshold.
  • the threshold values are different between the threshold value groups.
  • the threshold grouping can be flexibly adjusted according to the designer's classification requirements and the total number of thresholds.
  • the number of groups depends on the preset number of noise levels. For example, if n levels of noise levels are set according to the light intensity of the use environment, all thresholds in the threshold set can be divided into n threshold groups or n+1 threshold groups when threshold grouping is set.
  • the n threshold groups respectively correspond to each of the preset n noise levels.
  • the noise level in the threshold value group with a larger threshold value is greater than the noise level in the threshold value group with a smaller threshold value, and the minimum threshold value in each threshold value group meets the false alarm rate required by the system under the corresponding noise level.
  • the third gear noise levels con1, con2, and con3 are sequentially reduced.
  • the three threshold values of T3, T2 and T1 are carefully designed according to the level of natural light noise, which can ensure that when the natural light noise is con1, the lowest threshold is set to the false alarm rate that T3 meets the system requirements; when the natural light noise is con2, The lowest threshold is set to the false alarm rate that T2 meets the system requirements; when the natural light noise is con3, the lowest threshold is set to the false alarm rate that T1 meets the system requirements.
  • the above 12 thresholds are divided into four groups, namely:
  • CaseB T3; a total of 1 threshold
  • T1 has 1 threshold.
  • the above 12 thresholds are divided into three groups, which are divided into:
  • this grouping example is only exemplary. In actual applications, grouping can be performed as needed.
  • the number of groups is not limited to a certain numerical range, and the number of thresholds contained in each threshold group is not limited to a certain range. A range of values. Generally, a threshold group with a larger threshold has a larger number of thresholds, and a threshold group with a smaller threshold has a smaller number of thresholds.
  • a threshold can be added between T1 and T2, and the added threshold can be grouped with T1 when grouping, or a threshold can be added between T2 and T3, and the threshold can be added during grouping.
  • the added threshold is grouped with T2, or a threshold can be added between T3 and T4, and the added threshold is grouped with T3 when grouping.
  • grouping by threshold can decouple the collected data and pulse segmentation. After the data is collected, the effective data is filtered out, and the pulse segmentation is performed according to the effective data. If not grouped, the collected data and pulse segmentation are coupled together That is, each TDC does not know how many TDC data it needs to collect, and it needs to perform the cycle of "collection-pulse segmentation-judge whether to discard-judge whether to continue collecting" in real time. The logic to implement in TDC is more complicated.
  • the judging unit determines whether the electrical pulse signal is noise according to the minimum value in the threshold value group triggered by the received electrical pulse signal combined with the noise level, so as to filter out non-noise time information.
  • the judging unit is configured to filter time information belonging to non-noise in an order from the largest threshold group to the smallest threshold group. After the judging unit receives all the time information sent by the comparing unit, it first selects the non-noise time information according to the largest threshold group. When it is determined that the non-noise time information cannot be filtered out according to the largest threshold group, then Filter out non-noise time information according to the second largest threshold group, and so on.
  • the judging unit is configured to determine that the electrical pulse signal is not noise when the minimum value in the maximum threshold group, that is, the first threshold value is triggered by the electrical pulse signal.
  • the minimum value in the maximum threshold value group is also relatively large, it is generally determined that the electrical pulse signal is not noise when the first threshold value is triggered by the electrical pulse signal.
  • the detection circuit also presets the noise level corresponding to the maximum threshold value group, and the judging unit is also used to compare the noise level with the maximum threshold value when the first threshold value is triggered by the electrical pulse signal.
  • the noise levels corresponding to the groups are compared. When the noise level is less than the noise level corresponding to the first threshold, it is determined that the electrical pulse signal is not noise, and the first threshold is the minimum value in the maximum threshold group.
  • the noise level used for comparison with the preset noise level corresponding to the threshold value group may be measured by a real-time noise measurement device set in the ranging system, for example, an additional setting for receiving noise in the ranging system.
  • the ambient light noise is measured by a photoelectric sensor; or, it can also be measured by using the DC component of the optical signal detected by the detection circuit, which is not limited here.
  • the judging unit is configured to filter out time information that triggers other threshold groups when there is time information that triggers the first threshold, and then calculate the pulse information of the electrical pulse signal according to the first threshold.
  • the non-noise time information is filtered from the time information of the second largest threshold group triggered, that is, the time information belonging to the second largest threshold group is filtered out Non-noise time information.
  • the filtering time information belonging to non-noise from the time information of the second largest threshold group triggering includes: when there is time information for triggering the second largest threshold group, and the noise level is less than that corresponding to the second largest threshold group In the case of noise level, it is determined that the electrical pulse signal is not noise.
  • the time information of the second largest threshold group triggered is the time information of noise
  • the time information belonging to the non-noise is filtered from the time information of the third largest threshold group triggered, and when there is the time information of the third largest threshold group Time information and when the noise level is less than the noise level corresponding to the third largest threshold group, it is determined that the electrical pulse signal is not noise.
  • TDCs with different thresholds are set within the dynamic range of the circuit (thresholds are T1, T2,..., T12), and
  • the preset threshold height is T1 ⁇ T2 ⁇ ... ⁇ T12, as shown in Figure 3.
  • CaseA contains T4,...,T12, a total of 9 thresholds;
  • CaseB contains T3, a total of 1 threshold;
  • CaseC Contains 1 threshold for T2;
  • CaseD Contains 1 threshold for T1.
  • the values of the three thresholds T3, T2 and T1 are designed according to the three noise levels Con1, Con2, and Con3 respectively, that is, when the noise is Con1, the lowest threshold is set to the false alarm rate that T3 meets the system requirements; when the noise is When Con2, the lowest threshold is set to the false alarm rate that T2 meets the system requirements; when the noise is Con3, the lowest threshold is set to the false alarm rate that T1 meets the system requirements.
  • the determining unit is used to determine that the electrical pulse signal is not noise when there is time information that triggers the minimum threshold T4 in CaseA, and calculate the pulse of the electrical pulse signal according to the time information that triggers the minimum threshold T4 information.
  • the judging unit determines whether there is time information that triggers T3 in CaseB. If it exists, and the measured noise level is less than the time information that triggers the threshold T3 in CaseB. When the noise level is Con1, it is determined that the electrical pulse signal is not noise, and the pulse information of the electrical pulse signal is calculated according to the time information of the trigger T3. When there is time information for triggering T3 but the measured noise level is less than the noise level Con1 corresponding to the time information for triggering T3 in CaseB, it is determined that no non-noise signal is detected.
  • the judging unit determines whether there is time information that triggers T2 in CaseC, if it exists, and the measured noise level is less than that corresponding to the time information that triggers the threshold T2 in CaseC
  • the noise level is Con2
  • the pulse information of the electrical pulse signal is calculated according to the time information of the trigger T2.
  • the judging unit determines whether there is time information that triggers T1 in CaseD, if it exists, and the measured noise level is less than that corresponding to the time information that triggers the threshold T1 in CaseD
  • the noise level is Con3
  • the pulse information of the electrical pulse signal is calculated according to the time information of the trigger T1.
  • the calculation unit is configured to calculate at least one of the waveform, amplitude, and expansion of the electrical pulse signal according to the filtered time information and the corresponding threshold.
  • the calculation unit is configured to restore the electrical pulse signal to a waveform diagram of the light pulse according to the triggered threshold and the time information corresponding to the electrical pulse signal, so as to obtain the waveform, amplitude, and value on the waveform diagram. At least one of the widening.
  • the transmitter 203 emits a light pulse signal at regular intervals, and the light pulse signal to be collected by the detection circuit encounters the object and is reflected back. It must be located after the transmitter emits the optical pulse signal and between the emission of the next optical pulse signal. For the convenience of description, this period of time is taken as the collection time window. Therefore, the whole set of steps of collecting time information-filtering time information belonging to non-noise-calculating pulse information performed by the detection circuit is repeated in each collection time window.
  • twelve channels of TDC (T1, T2,..., T12) of different heights are set within the dynamic range of the circuit, and the preset threshold height has T1 ⁇ T2 ⁇ ... ⁇ T12, as shown in the figure 3 shown.
  • the time information is filtered according to the Case A, Case B, Case C, and Case D groups shown in Figure 2.
  • the comparison circuit acquires multiple time points as shown in Figure 3.
  • the calculation unit can obtain waveforms such as pulse 3 and pulse 4, pulse 1 and 2 will Filter out as noise.
  • the comparison circuit In another case, within one acquisition time window, the comparison circuit only acquires the 6 time points on the left shown in FIG. 3 (that is, the 6 time points corresponding to pulse 1 and pulse 2 in the figure). In this case, if you cannot find any useful data with Case A and Case B, you can return to case C to check whether there is time information that triggers Case C, and then you can see the 4 time points corresponding to T2. When it is determined that the current noise level is lower than For Con 2 corresponding to T2, pulse 1 and pulse 2 are simulated using these 4 time points.
  • the judging unit does not start searching from whether the minimum value in the maximum threshold group is triggered by the electrical pulse signal, but the judging unit directly starts from the electrical pulse Among the time information of the largest threshold group triggered by the signal, the non-noise time information is filtered out.
  • the judgment unit is configured to compare the noise level with the noise level corresponding to the largest threshold value group triggered by the electrical pulse signal to determine the electrical Whether the pulse signal is noise.
  • the judging unit determines that the electrical pulse signal is not noise; when the noise level is greater than the noise level corresponding to the threshold group , The determining unit determines that the electrical pulse signal is noise.
  • the time information belonging to non-noise is filtered out .
  • the filtering method is the same as the method for filtering time information belonging to non-noise in the largest threshold group and the second largest threshold group, and will not be repeated here.
  • the present invention also provides an optical signal detection method, including:
  • Step S1 receiving an electrical pulse signal converted from an optical pulse signal
  • Step S2 Perform a comparison operation between the electrical pulse signal and a threshold value set, and collect time information corresponding to the electrical pulse signal, wherein each threshold value in the threshold value set is divided into multiple threshold value groups in ascending order , Include at least one threshold in each threshold group;
  • Step S3 Filter out non-noise time information according to the minimum value in the threshold group triggered by the electrical pulse signal and the noise level;
  • Step S4 Calculate the pulse information of the electrical pulse signal according to the filtered time information.
  • the filtering out non-noise time information includes:
  • the first threshold When the first threshold is triggered by the electrical pulse signal, it is determined that the electrical pulse signal is not noise, and the first threshold is the minimum value in the maximum threshold group.
  • the filtering out non-noise time information includes:
  • the first threshold When the first threshold is triggered by the electrical pulse signal and the noise level is less than the noise level corresponding to the first threshold, it is determined that the electrical pulse signal is not noise, and the first threshold is the value in the maximum threshold group. Minimum value.
  • the filtering out non-noise time information includes:
  • the time information that triggers other threshold groups is filtered out.
  • the filtering out non-noise time information includes:
  • the non-noise time information is filtered from the time information of the second-largest threshold group that is triggered.
  • the selection of non-noise time information from the time information of the second-largest threshold group triggering includes:
  • the filtering out non-noise time information includes:
  • the non-noise time information is filtered out.
  • the filtering out non-noise time information includes:
  • the noise level is set to the noise corresponding to the largest threshold value group triggered by the electrical pulse signal Level comparison determines whether the electrical pulse signal is noise.
  • the determining unit determines that the electrical pulse signal is not noise
  • the judgment unit determines that the electrical pulse signal is noise.
  • the time information of the largest threshold group triggered by the electrical pulse signal is all noise
  • the time information of the second largest threshold group triggered by the electrical pulse signal filter out Non-noise time information
  • the thresholds in the threshold set are divided into at least three threshold groups in descending order.
  • the calculating the pulse information of the electrical pulse signal according to the filtered time information includes:
  • At least one of the waveform, amplitude, and expansion of the electrical pulse signal is calculated according to the filtered time information and the corresponding threshold.
  • step S1 and step S2 can be implemented by the comparison unit in the detection circuit of the foregoing embodiment
  • step S3 can be implemented by the judgment unit in the detection circuit of the foregoing embodiment
  • step S4 can be implemented by the detection circuit of the foregoing embodiment.
  • the present invention provides the above-mentioned detection circuit, detection method, distance measuring device and mobile platform.
  • the detection circuit receives an electrical pulse signal converted from an optical pulse signal and integrates the electrical pulse signal with a preset threshold. Perform a comparison operation, and divide each preset threshold in the preset threshold set into multiple threshold groups in descending order, and each threshold group contains at least one preset threshold; The minimum value in the threshold group triggered by the pulse signal and the noise level determine whether the electrical pulse signal is noise.
  • the determining unit determines that the electrical pulse signal is not noise, it will be based on the triggered threshold and the electrical
  • the time information corresponding to the pulse signal calculates the pulse information of the electrical pulse signal.
  • the low threshold grouping that does not meet the requirements can be dynamically abandoned according to the external light noise situation, ensuring that the lowest threshold is always above the noise amplitude, so as to optimize the lowest threshold of TDC so that under different ambient light noise levels, laser The ranging system can reach the widest detection range.

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

Abstract

L'invention concerne un circuit de détection (130), un procédé de détection, un appareil de télémétrie (200) et une plateforme mobile. Le circuit de détection (130) comprend : une unité de comparaison, utilisée pour recevoir un signal d'impulsion électrique converti à partir d'un signal d'impulsion optique, effectuer une opération de comparaison entre le signal d'impulsion électrique et un ensemble de seuils, et acquérir des informations de temps correspondant au signal d'impulsion électrique, des seuils de l'ensemble de seuils étant classés en une pluralité de groupes de seuils dans un ordre décroissant, et chaque groupe de seuils comprenant au moins un seuil ; une unité de détermination, utilisée pour obtenir des informations temporelles de non-bruit au moyen d'une sélection en fonction de la valeur minimale dans le groupe de seuils déclenché par le signal d'impulsion électrique et d'un niveau de bruit ; et une unité de calcul, utilisée pour calculer des informations d'impulsion du signal d'impulsion électrique en fonction des informations temporelles obtenues par sélection. En groupant des seuils prédéfinis, un seuil minimal de TDC est optimisé, de sorte que, sous différents niveaux de lumière ambiante et de bruit, un système laser de mesure de distance peut atteindre la plage de détection la plus grande.
PCT/CN2019/085221 2019-04-30 2019-04-30 Circuit de détection, procédé de détection, appareil de télémétrie et plateforme mobile WO2020220275A1 (fr)

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PCT/CN2019/085221 WO2020220275A1 (fr) 2019-04-30 2019-04-30 Circuit de détection, procédé de détection, appareil de télémétrie et plateforme mobile
CN201980008851.1A CN112236687A (zh) 2019-04-30 2019-04-30 一种探测电路、探测方法及测距装置、移动平台

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Families Citing this family (1)

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Publication number Priority date Publication date Assignee Title
CN115144863A (zh) * 2021-03-31 2022-10-04 上海禾赛科技有限公司 确定噪声水平的方法、激光雷达以及测距方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN207601308U (zh) * 2016-08-05 2018-07-10 上海思岚科技有限公司 一种激光测距装置
CN108401444A (zh) * 2017-03-29 2018-08-14 深圳市大疆创新科技有限公司 一种激光雷达以及基于激光雷达的时间测量方法
CN109085606A (zh) * 2017-06-14 2018-12-25 欧姆龙汽车电子株式会社 测距装置
US20190025413A1 (en) * 2017-07-20 2019-01-24 SZ DJI Technology Co., Ltd. Systems and methods for optical distance measurement
CN109597057A (zh) * 2018-12-06 2019-04-09 苏州镭图光电科技有限公司 一种激光回波测距方法及测距装置
CN109669188A (zh) * 2019-01-17 2019-04-23 杜鑫 多沿触发时间鉴别方法和脉冲式激光测距方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10585174B2 (en) * 2017-03-10 2020-03-10 Sensl Technologies Ltd. LiDAR readout circuit
WO2018176290A1 (fr) * 2017-03-29 2018-10-04 SZ DJI Technology Co., Ltd. Circuit de traitement de signaux de détection et télémétrie par ondes lumineuses (lidar)

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN207601308U (zh) * 2016-08-05 2018-07-10 上海思岚科技有限公司 一种激光测距装置
CN108401444A (zh) * 2017-03-29 2018-08-14 深圳市大疆创新科技有限公司 一种激光雷达以及基于激光雷达的时间测量方法
CN109085606A (zh) * 2017-06-14 2018-12-25 欧姆龙汽车电子株式会社 测距装置
US20190025413A1 (en) * 2017-07-20 2019-01-24 SZ DJI Technology Co., Ltd. Systems and methods for optical distance measurement
CN109597057A (zh) * 2018-12-06 2019-04-09 苏州镭图光电科技有限公司 一种激光回波测距方法及测距装置
CN109669188A (zh) * 2019-01-17 2019-04-23 杜鑫 多沿触发时间鉴别方法和脉冲式激光测距方法

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