WO2022209310A1 - 計測装置、およびプログラム - Google Patents

計測装置、およびプログラム Download PDF

Info

Publication number
WO2022209310A1
WO2022209310A1 PCT/JP2022/004779 JP2022004779W WO2022209310A1 WO 2022209310 A1 WO2022209310 A1 WO 2022209310A1 JP 2022004779 W JP2022004779 W JP 2022004779W WO 2022209310 A1 WO2022209310 A1 WO 2022209310A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
frequency
mode
frequency range
range
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2022/004779
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
宏幸 高木
安寿 稲田
泰宏 壁谷
弓子 加藤
建治 鳴海
孝平 菊池
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Intellectual Property Management Co Ltd
Original Assignee
Panasonic Intellectual Property Management Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Panasonic Intellectual Property Management Co Ltd filed Critical Panasonic Intellectual Property Management Co Ltd
Priority to JP2023510588A priority Critical patent/JPWO2022209310A1/ja
Priority to CN202280020085.2A priority patent/CN117015723A/zh
Priority to EP22779539.0A priority patent/EP4318042A4/en
Publication of WO2022209310A1 publication Critical patent/WO2022209310A1/ja
Priority to US18/468,720 priority patent/US20240004042A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/491—Details of non-pulse systems
    • G01S7/4911—Transmitters
    • 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
    • G01S17/32—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S17/34—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • 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
    • G01S17/50—Systems of measurement based on relative movement of target
    • G01S17/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/491—Details of non-pulse systems
    • G01S7/4912—Receivers
    • G01S7/4917—Receivers superposing optical signals in a photodetector, e.g. optical heterodyne detection
    • 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
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
    • G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles

Definitions

  • the present disclosure relates to measuring devices and programs.
  • LiDAR Light Detection and Ranging
  • a typical example of a measurement device using LiDAR technology comprises a light source, a photodetector, and a processing circuit.
  • a light source emits light for illuminating an object.
  • the photodetector detects a reflected wave from an object and outputs a signal corresponding to the time delay of the reflected wave.
  • the processing circuit acquires data on the distance and velocity of the object based on the signal output from the photodetector, for example, by FMCW (Frequency Modulated Continuous Wave) technology.
  • FMCW Frequency Modulated Continuous Wave
  • the present disclosure provides a measuring device that can acquire measurement data of an object by appropriately changing the ranging range.
  • a measurement device emits light for irradiating an object, a light source capable of changing the frequency of the light, separates the light into reference light and irradiation light, an interference optical system for generating interference light by causing interference between the reflected light generated by the reflected light from the object and the reference light; and receiving the interference light and outputting a signal corresponding to the intensity of the interference light.
  • a photodetector for controlling the light source and generating and outputting data relating to the distance and/or velocity of the object based on the signal output from the photodetector, wherein the processing circuit operates in a first mode and a second mode, causes the light source to emit light whose frequency changes with time within a first frequency range in the first mode, and emits light in the first frequency range and the first frequency range in the second mode.
  • the absolute value of the rate of frequency change over time in the first frequency range is the absolute value of the rate of change over time in the second frequency range
  • the center frequency of the first frequency range is different from the center frequency of the second frequency range
  • the lower limit of the first frequency range is different from the lower limit of the second frequency range.
  • a device may consist of one or more devices. When the device is composed of two or more devices, the two or more devices may be arranged in one device, or may be divided and arranged in two or more separate devices. As used herein and in the claims, a "device" can mean not only one device, but also a system of multiple devices. A plurality of devices included in a "system” may include devices installed in remote locations away from other devices and connected via a communication network.
  • FIG. 1 is a block diagram that schematically shows the configuration of a measurement device according to an exemplary embodiment of the present disclosure.
  • FIG. 2A is a diagram schematically showing temporal changes in the frequencies of reference light and reflected light when an object is stationary.
  • FIG. 2B is a diagram schematically showing temporal changes in the frequencies of reference light and reflected light when an object approaches the measuring device.
  • FIG. 3 is a graph showing the relationship between the distance from the measuring device to the object and the beat frequency.
  • FIG. 4 is a diagram schematically showing the relationship between the injection current value and the frequency of laser light in a distributed feedback laser diode.
  • FIG. 5 is a diagram for explaining the correspondence relationship between the current value range and the frequency range in the graph shown in FIG. FIG.
  • FIG. 6A is a diagram schematically showing the relationship between the frequency of laser light and time in a narrow range mode and a wide range mode.
  • FIG. 6B is a diagram schematically showing the relationship between laser light intensity and time in the narrow-range mode and the wide-range mode.
  • FIG. 7A is a flowchart illustrating an example of operations performed by a processing circuit.
  • FIG. 7B is a flow chart showing an example of the operation performed by the processing circuitry in step S101 shown in FIG. 7A.
  • FIG. 7C is a flow chart showing an example of operations performed by the processing circuitry in step S104 shown in FIG. 7A.
  • FIG. 8 is a perspective view schematically showing an example of a vehicle having a measuring device mounted on its front surface.
  • FIG. 9A is a diagram schematically showing an example of emitting flash light toward a target scene.
  • FIG. 9B is a diagram schematically showing the relationship between the intensity of the beat signal and the range-finding distance in the example shown in FIG. 9A.
  • FIG. 10A is a diagram schematically showing an example of emitting a plurality of line beams toward a target scene.
  • FIG. 10B is a diagram schematically showing the relationship between the strength of the beat signal and the measured distance in the example shown in FIG. 10A.
  • FIG. 11A is a diagram schematically showing an example of emitting a plurality of irradiation lights toward a target scene.
  • FIG. 11B is a diagram schematically showing the relationship between the strength of the beat signal and the range-finding distance in the example shown in FIG.
  • FIG. 12 is a flowchart illustrating an example of operations performed by a processing circuit in measuring an object in a target scene.
  • FIG. 13 is a flow chart showing another example of the operation of the processing circuit in measuring an object in the target scene.
  • FIG. 14A is a diagram showing an application example in which the measuring device is applied to in-vehicle equipment.
  • FIG. 14B is a diagram showing an application example in which the measuring device is applied to in-vehicle equipment.
  • FIG. 15A is a diagram showing an application example in which the measuring device is applied to an autonomous mobile body.
  • FIG. 15B is a diagram showing an application example in which the measuring device is applied to an autonomous mobile body.
  • FIG. 16A is a diagram showing an application example in which the measuring device is applied to a robot arm.
  • FIG. 16B is a diagram showing an application example in which the measuring device is applied to a robot arm.
  • all or part of a circuit, unit, device, member or section, or all or part of a functional block in a block diagram is, for example, a semiconductor device, a semiconductor integrated circuit (IC), or an LSI (large scale integration). ) may be performed by one or more electronic circuits.
  • An LSI or IC may be integrated on one chip, or may be configured by combining a plurality of chips.
  • functional blocks other than memory elements may be integrated into one chip.
  • LSIs or ICs may be called system LSIs, VLSIs (very large scale integration), or ULSIs (ultra large scale integration) depending on the degree of integration.
  • a Field Programmable Gate Array (FPGA), which is programmed after the LSI is manufactured, or a reconfigurable logic device that can reconfigure the connection relationships inside the LSI or set up the circuit partitions inside the LSI can also be used for the same purpose.
  • FPGA Field Programmable Gate Array
  • circuits, units, devices, members or parts can be executed by software processing.
  • the software is recorded on one or more non-transitory storage media, such as ROMs, optical discs, hard disk drives, etc., such that when the software is executed by a processor, the functions specified in the software are performed. It is executed by processors and peripherals.
  • a system or apparatus may include one or more non-transitory storage media on which software is recorded, a processor, and required hardware devices such as interfaces.
  • light refers not only to visible light (having a wavelength of about 400 nm to about 700 nm), but also to electromagnetic waves including ultraviolet rays (having a wavelength of about 10 nm to about 400 nm) and infrared rays (having a wavelength of about 700 nm to about 1 mm).
  • ultraviolet light may be referred to as “ultraviolet light”
  • infrared light may be referred to as "infrared light”.
  • Patent Documents 1 to 4 disclose measuring devices that adjust the range and accuracy of ranging by monotonically increasing or decreasing the frequency of light or millimeter waves over time.
  • monotonically increasing frequency with time is referred to as “up-chirp”
  • monotonically decreasing frequency with time is referred to as “down-chirp”.
  • the device disclosed in Patent Document 1 acquires measurement data of an object using light.
  • the frequency range and time range for the next down-chirp period are determined based on the measurement result in the up-chirp period. Further, the frequency range and time range for the next up-chirp period are determined based on the measurement results during the down-chirp period. In this way the ranging range and accuracy are adjusted.
  • the devices disclosed in Patent Documents 2 to 4 acquire measurement data of an object using millimeter waves.
  • the frequency of the millimeter wave periodically changes with time in a triangular waveform.
  • the range and accuracy of ranging are adjusted by changing the frequency range of the triangular wave or changing the transmission power of the millimeter wave.
  • the ranging range and accuracy are adjusted by changing the frequency range and time range for each cycle of the triangular wave.
  • the center frequency of the frequency range is constant.
  • the range and accuracy of distance measurement are adjusted by changing the frequency range for each cycle of the triangular wave in three stages, large, medium, and small.
  • the lower limit of the frequency range is constant.
  • a metrology device utilizes FMCW-LiDAR technology.
  • the measuring device measures an object by switching between two modes. As a result, the measurement data of the object can be obtained by appropriately changing the distance measurement range.
  • a measuring device according to an embodiment of the present disclosure and a program used for the measuring device will be described below.
  • a measurement device emits light for irradiating an object, a light source capable of changing the frequency of the light, separates the light into reference light and irradiation light, and An interference optical system that generates interference light by causing interference between the reflected light generated by the light reflected by the object and the reference light, and light that receives the interference light and outputs a signal corresponding to the intensity of the interference light.
  • a detector and processing circuitry for controlling the light source and for generating and outputting data relating to the distance and/or velocity of the object based on the signal output from the photodetector.
  • the processing circuit operates in a first mode and a second mode, causes the light source to emit light whose frequency changes with time within a first frequency range in the first mode, The light source emits light whose frequency changes with time within a second frequency range different from the frequency range.
  • the absolute value of the time rate of frequency change in the first frequency range is different from the absolute value of the time rate of frequency change in the second frequency range.
  • the center frequency of the first frequency range is different than the center frequency of the second frequency range.
  • the lower limit of the first frequency range is different from the lower limit of the second frequency range.
  • the measuring device is the measuring device according to the first item, wherein the frequency of the light in the first mode and the frequency of the light in the second mode periodically change with time.
  • a period of frequency change of the light in the first mode is equal to a period of frequency change of the light in the second mode.
  • the change in the amount of heating of the active layer contained in the laser diode due to the increase or decrease of the applied current becomes constant, and the frequency is linearly increased or decreased with time. can be maintained.
  • a measuring device is the measuring device according to the first or second item, wherein the absolute value of the rate of change over time of the frequency in the first frequency range is the rate of change over time of the frequency in the second frequency range. and the center frequency of the first frequency range is higher than the center frequency of the second frequency range.
  • This measuring device can accurately measure a narrow ranging range in the first mode, and can measure a wide ranging range with a certain degree of accuracy in the second mode. Furthermore, when a laser diode having a negative rate of change in the frequency of light with respect to the applied current value is used as the light source, the intensity of light in the second mode can be made higher than the intensity of light in the first mode.
  • a measuring device is the measuring device according to any one of the first to third items, wherein each cycle of the frequency change of the light in the first mode includes a first up-chirp period and a first a down-chirp period, and each period of frequency change of the light in the second mode includes a second up-chirp period and a second down-chirp period.
  • the frequency monotonically increases from the lower limit value to the upper limit value of the first frequency range, and during the first down-chirp period, the frequency increases from the upper limit value to the lower limit value of the first frequency range.
  • the frequency monotonically increases from the lower limit value to the upper limit value of the second frequency range, and during the second down-chirp period, the frequency increases from the upper limit value to the lower limit value of the second frequency range. monotonically decreasing to
  • the frequency can be changed over time like a triangular wave.
  • the measuring device is the measuring device according to the fourth item, wherein in the first mode, the signal is the first signal corresponding to the intensity of the interference light based on the light in the first up-chirp period. and a second signal component corresponding to the intensity of the interference light based on the light during the first down-chirp period, and in the second mode, the signal is the A third signal component corresponding to the intensity of the interfering light based on the light and a fourth signal component corresponding to the intensity of the interfering light based on the light during the second down-chirp period are included.
  • the processing circuit in the first mode, generates and outputs the data relating to the distance and/or velocity of the object based on the first signal component and the second signal component, and in the second mode, Generating and outputting said data relating to the distance and/or velocity of said object based on said third signal component and said fourth signal component.
  • this measuring device can generate not only data on the distance of an object but also data on its velocity.
  • a measuring device is the measuring device according to the fourth or fifth item, wherein the length of the first up-chirp period and the length of the first down-chirp period are equal to each other, and the length of the second up-chirp period is equal to each other. The length of the period and the length of the second down-chirp period are equal to each other.
  • This measurement device is advantageous in maintaining the operation of increasing and decreasing the frequency linearly with time.
  • a measuring device is the measuring device according to any one of the first to sixth items, wherein the processing circuit detects the frequency of the light in each of the first mode and the second mode. It may be changed into a triangular wave shape.
  • a computer program according to the eighth item is a computer program executed by a computer in a system including a measuring device.
  • the measuring device emits light for irradiating an object, a light source capable of changing the frequency of the light, and separates the light into reference light and irradiation light, and the irradiation light irradiates the object.
  • an interference optical system for generating interference light by causing the reflected light and the reference light to interfere with each other; and a photodetector for receiving the interference light and outputting a signal corresponding to the intensity of the interference light.
  • the computer program causes the computer to emit light whose frequency changes with time in a first frequency range in the first mode, and whose frequency changes with time in a second frequency range in the second mode.
  • the absolute value of the time rate of frequency change in the first frequency range is different from the absolute value of the time rate of frequency change in the second frequency range.
  • the center frequency of the first frequency range is different than the center frequency of the second frequency range.
  • the lower limit of the first frequency range is different from the lower limit of the second frequency range.
  • FIG. 1 is a block diagram that schematically shows the configuration of a measurement device according to an exemplary embodiment of the present disclosure.
  • FIG. 1 shows an object 10 to be measured.
  • the measurement apparatus 100 shown in FIG. 1 includes a light source 20, an interference optical system 30, a beam shaper 40, an optical deflector 50, a photodetector 60, a processing circuit 70, and a memory 72.
  • the thick line arrows shown in FIG. 1 represent the flow of light.
  • the thin line arrows shown in FIG. 1 represent transmission and reception of signals.
  • the light source 20 emits a laser beam 20L0 whose frequency can be changed.
  • the frequency can be time-varying, for example, in a triangular or sawtooth shape with a constant time period.
  • the time period of frequency change may vary.
  • the time period of the frequency can be, for example, greater than or equal to 1 microsecond and less than or equal to 10 milliseconds.
  • the frequency width of the frequencies may be, for example, 100 MHz or more and 1 THz or less.
  • the wavelength of the laser light can be included in the near-infrared wavelength range of 700 nm or more and 2000 nm or less, for example.
  • the amount of near-infrared light is less than that of visible light, so if near-infrared light is used as the laser light 20L0 , the influence of sunlight as noise can be reduced.
  • the wavelength of the laser light 20L 0 may be included in the visible light wavelength range of 400 nm or more and 700 nm or less, or may be included in the ultraviolet light wavelength range.
  • Light source 20 may include, for example, a distributed feedback laser diode or an external cavity laser diode. These laser diodes are inexpensive and small, are capable of single-mode oscillation, and can change the frequency of laser light according to the amount of current applied. The relationship between the applied current value and the frequency of the laser light 20L0 will be described later.
  • Interference optics 30 includes a first fiber splitter 32 , a second fiber splitter 34 and an optical circulator 36 .
  • the first fiber splitter 32 splits the laser light 20L 0 emitted from the light source 20 into a reference light 20L 1 and an illumination light 20L 2 .
  • the first fiber splitter 32 inputs the reference light 20L 1 into the second fiber splitter 34 and the illumination light 20L 2 into the optical circulator 36 .
  • Optical circulator 36 inputs illumination light 20L 2 to beam shaper 40 .
  • the optical circulator 36 illuminates the object 10 with the illumination light 20L 2 and inputs the reflected light 20L 3 to the second fiber splitter 34 .
  • the second fiber splitter 34 inputs to the photodetector 60 an interference light 20L 4 obtained by superimposing and interfering the reference light 20L 1 and the reflected light 20L 3 .
  • the beam shaper 40 adjusts the spot shape of the irradiation light 20L2 emitted from the interference optical system 30.
  • the illuminating light 20L2 after beam shaping can be, for example, a flash light, a line beam, or a point beam.
  • Beam shaper 40 may include, for example, a collimating lens.
  • the optical deflector 50 changes the direction of the illumination light 20L 2 emitted from the beam shaper 40 .
  • the light deflector 50 allows the target scene, including the object 10, to be scanned with the illumination light 20L2 .
  • the optical deflector 50 may include, for example, a MEMS (Micromechanical Electrosystem) mirror or a galvanomirror.
  • the optical deflector 50 may be a beam scanning device using optical phased arrays and slow light waveguides, as described in WO2019/130720.
  • a photodetector 60 detects the interference light 20L4 .
  • Photodetector 60 includes one or more photodetection elements. The photodetector outputs a signal corresponding to the intensity of the interference light 20L4 based on the laser light 20L0.
  • the optical path of the irradiation light 20L2 from the interference optical system 30 to the object 10 and the optical path of the reflected light 20L3 from the object 10 to the interference optical system 30 overlap each other.
  • the configuration of the measurement apparatus 100 can be simplified, and stable measurement can be achieved.
  • the two optical paths may be designed so as not to overlap each other.
  • a processing circuit 70 controls the operation of the light source 20 , the beam shaper 40 , the optical deflector 50 and the photodetector 60 .
  • Processing circuitry 70 processes the signal output from photodetector 60 using FMCW-LiDAR technology.
  • the processing circuit 70 generates and outputs measurement data regarding the distance and/or speed of the object 10 based on the signal. Details of the operation of the processing circuit 70 will be described later.
  • measurement device 100 comprises a processing unit including processing circuitry 70 and memory 72 .
  • the processing circuitry 70 and memory 72 may be integrated on one circuit board or provided on separate circuit boards.
  • the control and signal processing functions of processing circuit 70 may be distributed over multiple circuits.
  • the processor is remotely located away from other components and controls the operation of light source 20, beam shaper 40, optical deflector 50, and photodetector 60 via a wired or wireless communication network.
  • FIG. 2A is a diagram schematically showing temporal changes in the frequencies of the reference light 20L1 and the reflected light 20L3 when the object 10 is stationary.
  • a solid line represents the reference beam and a dashed line represents the reflected beam.
  • the frequency of the reference light 20L1 shown in FIG. 2A repeats a triangular wave-like temporal change. That is, the frequency of the reference light 20L1 repeats up-chirp and down-chirp. The increase in frequency in up-chirp and the decrease in frequency in down-chirp are equal to each other.
  • the frequency of reflected light 20L3 shifts along the time axis compared to the frequency of reference light 20L1 .
  • the amount of time shift of the reflected light 20L- 3 is equal to the time it takes for the illumination light 20L- 2 to be emitted from the measuring device 100, reflected by the object 10, and returned as the reflected light 20L- 3 .
  • the interference light 20L- 4 obtained by superimposing and interfering with the reference light 20L- 1 and the reflected light 20L- 3 has a frequency corresponding to the difference between the frequency of the reflected light 20L- 3 and the frequency of the reference light 20L- 1 .
  • a double arrow shown in FIG. 2A represents the difference between the two frequencies.
  • the photodetector 60 outputs a signal indicative of the intensity of the interference light 20L4 .
  • the signal is called a beat signal.
  • the frequency of the beat signal, ie the beat frequency is equal to the above frequency difference.
  • Processing circuitry 70 can generate data regarding the distance of object 10 from the beat frequencies.
  • FIG. 2B is a diagram schematically showing temporal changes in the frequencies of the reference light 20L1 and the reflected light 20L3 when the object 10 approaches the measuring device 100.
  • FIG. When the object 10 approaches, due to the Doppler shift, the frequency of the reflected light 20L3 shifts in an increasing direction along the frequency axis compared to when the object 10 is stationary. The amount by which the frequency of reflected light 20L3 shifts depends on the component of the velocity vector of object 10 projected in the direction of reflected light 20L3 .
  • the beat frequency differs between the up-chirp period and the down-chirp period of the reference light 20L1 and the reflected light 20L3 . In the example shown in FIG.
  • processing circuitry 70 can generate data about the velocity of object 10 from the difference in beat frequencies due to Doppler shift. In addition, the processing circuit 70 can generate data regarding the distance of the object 10 from the average values of the beat frequencies during the up-chirp and down-chirp periods.
  • ⁇ f is the frequency range in the up-chirp period or down-chirp period
  • ⁇ t is the time required to change ⁇ f
  • c is the speed of light
  • d is the distance from the measuring device 100 to the object 10
  • the beat frequency f beat is given by the following equation ( 1).
  • the beat frequency f beat in equation (1) is obtained by multiplying the time rate of change ⁇ f/ ⁇ t of the frequency by the round-trip time (2d/c) from the measuring device 100 to the object 10 .
  • FIG. 3 is a graph showing the relationship between the distance d from the measuring device 100 to the object 10 and the beat frequency f beat according to Equation (1).
  • the thin horizontal dashed line is an example of the maximum measurable value of the beat frequency f beat , which is 75 MHz.
  • the distance measurement range d increases as the time rate of change ⁇ f/ ⁇ t of the frequency decreases.
  • the range d is 9 m in the mode with a high rate of frequency change over time, and 100 m in the mode with a low rate of change over time. is.
  • a mode with a high rate of frequency change over time is a mode with a narrow ranging range, that is, a narrow range mode.
  • a mode with a low rate of frequency change over time is a mode with a wide ranging range, that is, a wide range mode.
  • the accuracy of distance measurement is improved as the time rate of frequency change increases. This is because the higher the time rate of change ⁇ f/ ⁇ t of the frequency, the greater the amount of change in the beat frequency f beat with respect to the amount of change in the distance d.
  • the beat frequency f beat is obtained by Fourier transforming the beat signal with respect to time. The greater the amount of change in the beat frequency f beat compared to the frequency resolution of the Fourier transform, the greater the accuracy of ranging. In the example shown in FIG. 3, when distance measurement is performed with a frequency resolution of 800 Hz, the distance measurement accuracy is about 0.1 mm in the narrow range mode and about several mm in the wide range mode. The distance measurement accuracy is 50 repetition accuracy.
  • the beat frequency f beat obtained by adding the amount of change due to the Doppler shift is required to be equal to or less than the maximum measurable value.
  • the narrow range mode can be applied, for example, when generating accurate measurement data of the object 10 at a short distance.
  • the short distance can be, for example, 0 m or more and 10 m or less.
  • the wide range mode may be applied, for example, when generating measurement data of objects 10 at near and far distances with some degree of accuracy.
  • the far distance can be, for example, greater than 10m and less than or equal to 200m.
  • the time rate of change of frequency in the narrow-range mode and the wide-range mode are determined by the maximum measurable value of the beat frequency f beat in equation (1) and the near and far distances d, respectively.
  • the narrow range mode is also called "first mode”
  • the wide range mode is also called "second mode".
  • FIG. 4 is a diagram schematically showing the relationship between the applied current value and the frequency of the laser light 20L0 in the distributed feedback laser diode.
  • the frequency of the laser light changes nonlinearly with respect to the applied current value. Even if the applied current changes linearly with time, the frequency of the laser light does not actually change linearly. Therefore, unlike the example shown in FIG. 2A, the actually measured beat frequency f beat is not constant over time. Using such a beat frequency f beat will reduce the accuracy of ranging. A decrease in ranging accuracy can be improved by, for example, the following two methods.
  • the frequency of the laser light can be changed linearly by monitoring the change in the frequency of the laser light due to the applied current value with a measuring instrument and feeding back the results to adjust the applied current value.
  • Another method is as follows.
  • the applied current is periodically changed in a triangular waveform over time, and the time change of the beat signal vibrating following the change is plotted. From the plotted results, the applied current value is associated with the round trip time during which the beat signal oscillates once with respect to the current value.
  • the correction ratio of the round trip time to the applied current value can be found.
  • a correction table indicating the correction ratio is stored in a storage device (not shown) provided separately in the measurement apparatus 100 .
  • the processing circuit 70 refers to the correction table and multiplies the round-trip time of the beat signal by a correction ratio according to the applied current value, that is, rescaling, thereby correcting the time change of the beat signal.
  • a correction ratio according to the applied current value, that is, rescaling, thereby correcting the time change of the beat signal.
  • the rescaling method does not require a separate measuring device, and signal processing can improve the reduction in distance measurement accuracy.
  • the cost can be reduced by the amount that the measuring equipment is not required.
  • the lower the nonlinearity of the frequency of the laser light with respect to the applied current value the less the deterioration of the distance measurement accuracy can be improved. If rescaling does not improve the deterioration of the ranging accuracy, the ranging accuracy does not improve even if the time rate of change ⁇ f/ ⁇ t of the frequency is high.
  • the portion where the frequency of the laser light changes nonlinearly with respect to the current value is used for the narrow range mode and the wide range mode. Furthermore, the DC component of the current value is the same in the narrow range mode and the wide range mode.
  • the frequency range in narrow range mode includes the frequency range in wide range mode. In other words, the upper limit of the frequency range in the narrow range mode is higher than the upper limit of the frequency range in the wide range mode, and the lower limit of the frequency range in the narrow range mode is lower than the lower limit of the frequency range in the wide range mode.
  • FIG. 5 is a diagram for explaining the correspondence relationship between the current value range and the frequency range in the graph shown in FIG. 5
  • ⁇ I 1 , ⁇ I 2 , and ⁇ I 3 are continuously arranged in this order in the direction in which the current value increases.
  • ⁇ f 1 , ⁇ f 2 , and ⁇ f 3 are continuously arranged in this order in the direction of decreasing frequency.
  • ⁇ f 1 , ⁇ f 2 , and ⁇ f 3 are the ranges of frequencies obtained when the current values vary through the ranges of ⁇ I 1 , ⁇ I 2 , and ⁇ I 3 , respectively.
  • the graph shown in FIG. 5 is divided into a first correspondence between ⁇ I1 and ⁇ f1, a second correspondence between ⁇ I2 and ⁇ f2, and a third correspondence between ⁇ I3 and ⁇ f3.
  • Each correspondence is approximately linear. Therefore, feedback or rescaling by the monitor is not necessary. Even when the applied current value is adjusted by feedback from the monitor, since the corresponding relationship is almost linear, it is possible to improve the decrease in distance measurement accuracy with a slight adjustment.
  • the width of the range of current values satisfies the relationship of ⁇ I 1 > ⁇ I 2 > ⁇ I 3
  • the width of the frequency range satisfies the relationship of ⁇ f 2 > ⁇ f 3 > ⁇ f 1 .
  • the ratio of the frequency range to the current value range satisfies the relationship ⁇ f 3 / ⁇ I 3 > ⁇ f 2 / ⁇ I 2 > ⁇ f 1 / ⁇ I 1 .
  • the range of current values in which linearity is obtained is the widest among the three correspondences, but the frequency range is the narrowest among the three correspondences.
  • the range of current values in which linearity is obtained is narrower than in the first correspondence, but the frequency range is the widest among the three correspondences.
  • the range of current values in which linearity is obtained is the narrowest among the three correspondences, but the frequency range is wider than that of the first correspondence.
  • the second correspondence relationship when the applied current is changed with time in a triangular waveform with the same period 2 ⁇ t, the second correspondence relationship can be applied to the narrow range mode, and the first and third correspondence relationships are applicable to the wide range mode. can be applied to This is because the time rate of frequency change in the second correspondence relationship is higher than the time rate of frequency change in the first and third correspondence relationships.
  • a higher intensity of the illumination light 20L2 can obtain effective reflected light 20L3 from the object 10 at a long distance.
  • the intensity of the laser light 20L0 emitted from the light source 20 increases with the applied current value.
  • the third correspondence relationship is more suitable for the wide-range mode than the first correspondence relationship in terms of obtaining a higher - intensity illumination light 20L2.
  • the intensity of the irradiation light 20L2 is equal to or less than a predetermined intensity regardless of the wide range mode or the narrow range mode. This is because it is assumed that a person suddenly enters a short distance, or that a person observes the object with binoculars from a long distance. If the wavelength is 1550 nm and the period 2 ⁇ t of the triangular wave is long enough to be 10 sec or more in continuous emission, the intensity of the illumination light 20L2 can be, for example, 10 mW or less. Objects 10 with low reflectance may exist even at short distances. Therefore, it is advantageous for the intensity of the illumination light 20L2 to be as high as possible within 10 mW, regardless of the wide range mode and the narrow range mode.
  • FIG. 6A is a diagram schematically showing the relationship between the frequency and time of the laser light 20L0 in narrow range mode and wide range mode.
  • FIG. 6B is a diagram schematically showing the relationship between the intensity of the laser light 20L0 and time in the narrow range mode and the wide range mode.
  • the narrow range modes shown in FIGS. 6A and 6B are based on the second correspondence shown in FIG.
  • the wide range mode shown in FIGS. 6A and 6B is based on the third correspondence shown in FIG.
  • the frequency of the laser light 20L 0 in the narrow range mode periodically changes with time within the frequency range ⁇ f 2
  • the frequency of the laser light 20L 0 in the wide range mode changes within the frequency range ⁇ f 3 .
  • the period 2 ⁇ t of the frequency change of the laser light 20L0 in the narrow range mode and the wide range mode are equal to each other.
  • Each period of frequency change in the narrow range mode includes the following first up-chirp period and second up-chirp period.
  • the frequency monotonously increases from the lower limit to the upper limit of the frequency range ⁇ f2
  • the frequency monotonously decreases from the upper limit to the lower limit of the frequency range ⁇ f2.
  • Each period of frequency change in the wide range mode includes the following second up-chirp period and second down-chirp period.
  • the frequency monotonously increases from the lower limit to the upper limit of the frequency range ⁇ f3
  • the second down-chirp period the frequency monotonously decreases from the upper limit to the lower limit of the frequency range ⁇ f3 .
  • first up-chirp period and the first down-chirp period are equal to each other, and the second up-chirp period ⁇ t and the second down-chirp period are equal to each other, it is advantageous to maintain the aforementioned linear increase and decrease of the frequency. .
  • first up-chirp period and the second up-chirp period are equal to each other, and the first down-chirp period and the second down-chirp period are equal to each other, it is further advantageous to maintain the aforementioned linear increase and decrease of the frequency. be.
  • the first up-chirp period, the first down-chirp period, the second up-chirp period, and the second down-chirp period are all ⁇ t.
  • the signal output from the photodetector 60 in the narrow range mode includes a first signal component during the first up-chirp period and a second signal component during the first down-chirp period.
  • Processing circuitry 70 generates and outputs measurement data based on the first and second signal components.
  • the signal output from photodetector 60 in the wide range mode includes a third signal component during the second up-chirp period and a fourth signal component during the second down-chirp period.
  • Processing circuitry 70 generates and outputs measurement data based on the third and fourth signal components.
  • the measurement data in the narrow-range mode and the wide-range mode generated as described above include not only data regarding the distance of the object 10 but also data regarding its velocity.
  • the width of the frequency range ⁇ f2 in the narrow range mode is wider than the width of the frequency range ⁇ f3 in the wide range mode.
  • the frequency range ⁇ f 2 in the narrow range mode and the frequency range ⁇ f 3 in the wide range mode do not overlap each other except for the following frequencies.
  • This frequency is a frequency at which the lower limit value of the frequency range ⁇ f2 in the narrow range mode and the upper limit value of the frequency range ⁇ f3 in the wide range mode match.
  • the absolute value ⁇ f 2 / ⁇ t of the frequency time change rate within the frequency range ⁇ f 2 in the narrow range mode is the absolute value ⁇ f 3 / ⁇ t of the frequency time change rate within the frequency range ⁇ f 3 in the wide range mode.
  • the center frequency of the frequency range ⁇ f2 in the narrow range mode is higher than the center frequency of the frequency range ⁇ f3 in the wide range mode.
  • the upper and lower limits of the frequency range ⁇ f2 in the narrow range mode are respectively higher than the upper and lower limits of the frequency range ⁇ f3 in the wide range mode.
  • the frequencies in the narrow range mode are equal to or higher than the frequencies in the wide range mode.
  • the width of the frequency range ⁇ f2 in the narrow range mode is different from the width of the frequency range ⁇ f3 in the wide range mode.
  • the absolute value of the time rate of frequency change within the frequency range ⁇ f2 in the narrow range mode is different from the absolute value of the time rate of frequency change within the frequency range ⁇ f2 in the wide range mode.
  • the center frequency of the frequency range ⁇ f2 in the narrow range mode is different from the center frequency of the frequency range ⁇ f3 in the wide range mode.
  • the upper and lower limits of the frequency range ⁇ f2 in the narrow range mode are different from the upper and lower limits of the frequency range ⁇ f3 in the wide range mode.
  • the width of the intensity range in the narrow range mode is wider than the width of the intensity range in the wide range mode.
  • the intensity range in narrow-range mode and the intensity range in wide-range mode do not overlap each other, except for the following intensities.
  • the intensity is an intensity at which the upper limit value of the intensity range in the narrow range mode and the lower limit value of the intensity range in the wide range mode match.
  • the absolute value of the time rate of change of intensity within the intensity range in the narrow range mode is higher than the absolute value of the time rate of change of intensity within the intensity range in the wide range mode.
  • the central intensity of the intensity range in the narrow range mode is lower than the central intensity of the intensity range in the wide range mode.
  • the upper and lower limits of the intensity range in the narrow range mode are respectively lower than the upper and lower limits of the intensity range in the wide range mode.
  • the intensity in the wide-range mode is greater than or equal to the intensity in the narrow-range mode. Therefore, effective reflected light 20L 3 can be obtained from distant object 10 in wide range mode. If the intensity in the narrow range mode is also high enough, a useful reflected light 20L3 can be obtained even from a low reflectance object 10 at a short distance.
  • the intensity in the narrow range mode can be, for example, ⁇ 1 mW and ⁇ 6 mW.
  • the intensity in wide range mode can be, for example, ⁇ 6 mW and ⁇ 10 mW.
  • the width of the intensity range in the narrow range mode is different from the width of the intensity range in the wide range mode.
  • the absolute value of the time rate of change of intensity within the intensity range in the narrow range mode differs from the absolute value of the time rate of change of intensity within the intensity range in the wide range mode.
  • the central intensity of the intensity range in the narrow range mode is different from the central intensity of the intensity range in the wide range mode.
  • the upper and lower limits of the intensity range in the narrow range mode are different from the upper and lower limits of the intensity range in the wide range mode, respectively.
  • the range of current values ⁇ I1 to ⁇ I3 shown in FIG. 5 is an example. Unlike the example shown in FIG. 5, the current value ranges ⁇ I1 and ⁇ I2 may partially overlap each other, and the current value ranges ⁇ I2 and ⁇ I3 may partially overlap each other. They may overlap. For example, if the current value ranges ⁇ I2 and ⁇ I3 partially overlap each other, the lower limit of the current value range ⁇ I2 ⁇ the lower limit of the current value range ⁇ I3 ⁇ the upper limit of the current value range ⁇ I2 The relation of value ⁇ the upper limit of the current value range ⁇ I3 is satisfied.
  • the frequency range ⁇ f2 in the narrow range mode and the frequency range ⁇ f3 in the wide range mode partially overlap each other , and the lower limit of the frequency range ⁇ f3 ⁇ the lower limit of the frequency range ⁇ f2 ⁇ the frequency range ⁇ f3 ⁇ the upper limit of the frequency range ⁇ f 2 is satisfied.
  • the intensity range in the narrow-range mode and the intensity range in the wide-range mode partially overlap each other, and the lower limit of the intensity range in the narrow-range mode ⁇ the lower limit of the intensity range in the wide-range mode ⁇ the intensity in the narrow-range mode
  • the relationship of upper limit of range ⁇ upper limit of intensity range in wide range mode is satisfied.
  • FIG. 7A is a flow chart illustrating an example of operations performed by processing circuitry 70 .
  • the processing circuit 70 performs the operations of steps S101 to S105 shown in FIG. 7A.
  • 7B and 7C are flow charts showing examples of operations performed by processing circuitry 70 in steps S101 and S104 shown in FIG. 7A, respectively.
  • Processing circuitry 70 measures objects 10 at long range or near range in wide range mode. The details of this operation are as shown in FIG. 7B.
  • the processing circuit 70 causes the light source 20 to emit the laser light 20L0 whose frequency changes with time in the wide range mode (step S101A).
  • the processing circuit 70 causes the photodetector 60 to detect the interference light 20L4 (step S101B).
  • Processing circuit 70 generates and outputs measurement data relating to the distance and speed of object 10 based on the signal output from photodetector 60 (step S101C).
  • Step S102> The processing circuit 70 determines whether the object 10 is at a short distance from the measurement result in step S101. A measurement result by another measurement sensor may be used instead of the measurement result in step S101. If the determination is Yes, processing circuit 70 performs the operation of step S103. If the determination is No, processing circuit 70 performs the operation of step S101.
  • Processing circuitry 70 determines if it is possible to measure in narrow range mode. In the narrow range mode, if the beat frequency including the Doppler shift is below the measurable upper limit, the measurement can be performed in the narrow range mode. If the determination is Yes, processing circuit 70 performs the operation of step S104. If the determination is No, processing circuit 70 performs the operation of step S101.
  • Processing circuitry 70 measures objects 10 at close range in narrow range mode. The details of this operation are as shown in FIG. 7C.
  • the processing circuit 70 causes the light source 20 to emit the laser light 20L0 whose frequency changes with time in the narrow range mode (step S104A).
  • the processing circuit 70 causes the photodetector 60 to detect the interference light 20L4 (step S104B).
  • Processing circuit 70 generates and outputs measurement data relating to the distance and speed of object 10 based on the signal output from photodetector 60 (step S104C).
  • the ranging accuracy in the narrow range mode in step S104 is improved compared to the ranging accuracy in the wide range mode in step S101.
  • Step S105 Processing circuitry 70 determines whether to end the measurement. If the determination is Yes, processing circuitry 70 terminates the measurement operation. If the determination is No, processing circuit 70 performs the operation of step S102. However, in step S102, the processing circuit 70 determines whether the object 10 is at a short distance based on the distance measurement result in step S104 instead of the measurement result in step S101.
  • the measurement data of the object 10 is acquired by appropriately changing the range and accuracy of distance measurement and the intensity of the irradiation light 20L2 . can do.
  • the processing circuitry 70 In measuring an object in a scene of interest, the processing circuitry 70 generates measurement data for the object in wide range mode or narrow range mode, as shown in FIG. 7A. If an object is present at a short distance and can be measured in narrow range mode, processing circuitry 70 switches from wide range mode to narrow range mode.
  • FIG. 8 is a perspective view schematically showing an example of a vehicle 200 having the measuring device 100 mounted on its front surface.
  • the traveling direction of the vehicle 200 is parallel to the X direction
  • the vehicle height direction is parallel to the Y direction
  • the crossing direction is parallel to the Z direction.
  • the vehicle height direction is a direction perpendicular to the road surface and a direction away from the road surface.
  • the measuring device 100 in the vehicle 200 emits the irradiation light 10L2 toward the target scene in front of the vehicle 200.
  • the irradiation light 20L2 is flash light, but it may be a line beam or a point beam.
  • the illuminating light will be referred to as “flash light”, “line beam” or “point beam”.
  • the mounting position of the measuring device 100 on the vehicle 200 is not limited to its front surface, but may be its upper surface, side surface, or rear surface. The mounting position is appropriately determined depending on where the target scene is.
  • photodetector 60 which includes a single photodetector element, detects interfering light 20L4 .
  • FIG. 9A is a diagram schematically showing an example of emitting the flash light 20L2 toward the target scene.
  • a rectangular area surrounded by a thick solid line represents the target scene ahead as seen from the vehicle 200 traveling on the road.
  • the preceding vehicle is running on the road, and there are pedestrians on the sidewalk on the side of the road. There are three trees along the sidewalk.
  • the five objects in the target scene are, in descending order of distance, a pedestrian, three roadside trees, and a preceding vehicle.
  • the distances to the pedestrian, the leftmost, middle, and rightmost street trees, and the preceding vehicle are d1 to d5 , respectively .
  • the dashed rectangle shown in FIG. 9A represents the illuminated spot of flash light 20L2 .
  • the illuminated spot of flash light 20L2 shown in FIG. 9A includes five objects in the target scene.
  • photodetector 60 which includes a single photodetector element, detects interfering light 20L4 .
  • the road surface when looking forward from the vehicle 200, the road surface gradually changes toward the vehicle height direction. A road surface changes continuously, whereas an object such as a person or a vehicle on the road surface changes discontinuously with respect to the road surface. Therefore, by illuminating an object with the flash light 20L2 , it is possible to detect the object.
  • FIG. 9B is a diagram schematically showing the relationship between the strength of the beat signal and the range-finding distance in the example shown in FIG. 9A.
  • Five peaks appear due to irradiation with flash light 20L2 .
  • the distances to the five objects can be measured at once.
  • a single photodetector can quickly determine the distances of five objects.
  • FIG. 10A is a diagram schematically showing an example of emitting a plurality of line beams 20L2 toward a target scene.
  • the dashed ellipses shown in FIG. 10A represent irradiation spots of the first line beam 20L 2a to the fourth line beam 20L 2d emitted at four different angles along the Z direction.
  • the distances at the top, middle, and bottom within the illumination spot of line beam 20L2 do not change significantly as its exit angle changes along the Z direction. Therefore, when scanning the target scene in the horizontal direction with the line beam 20L2 extending in the vertical direction, there is an advantage that the distance resolution in the horizontal direction is high.
  • the irradiation spot of the first line beam 20L 2a includes the leftmost street tree.
  • the irradiation spot of the second line beam 20L 2b includes the central street tree.
  • the irradiation spot of the third line beam 20L 2c includes the pedestrian and the rightmost street tree.
  • the irradiation spot of the fourth line beam 20L2d includes the preceding vehicle.
  • the first line beam 20L 2a to the fourth line beam 20L 2d may be emitted toward the target scene in this order or in the reverse order.
  • the first line beam 20L 2a to the fourth line beam 20L 2d are irregular like the third line beam 20L 2c , the second line beam 20L 2b , the fourth line beam 20L 2d and the first line beam 20L 2a . can be emitted in any order.
  • FIG. 10B is a diagram schematically showing the relationship between the strength of the beat signal and the measured distance in the example shown in FIG. 10A.
  • the four diagrams in FIG. 10B show beat signals generated by the irradiation of the first line beam 20L 2a to the fourth line beam 20L 2d .
  • Single peaks appear at distances d 2 , d 3 and d 5 respectively due to the irradiation of the first line beam 20L 2a , the second line beam 20L 2b and the fourth line beam 20L 2d .
  • two peaks appear at distances d1 and d4 due to the irradiation of the third line beam 20L2c .
  • the measuring apparatus 100 can measure the distances to the plurality of objects at once by irradiating the plurality of objects with one line beam 20L2 . From the known exit angles of the first line beam 20L 2a to the fourth line beam 20L 2d , a single photodetector element can quickly know the rough positions of five objects.
  • FIG. 11A is a diagram schematically showing an example of emitting a plurality of point beams 20L2 toward a target scene.
  • the dashed ellipses shown in FIG. 11A represent the irradiation spots of the fifth point beam 20L 2e to the ninth point beam 20L 2i emitted at five different angles along the Y direction.
  • FIG. 11B is a diagram schematically showing the relationship between the strength of the beat signal and the range-finding distance in the example shown in FIG. 11A.
  • the five diagrams of FIG. 11B show the beat signal resulting from the illumination of the fifth point beam 20L 2e to the ninth point beam 20L 2i .
  • a single peak at distance d4 appears due to the illumination of the fifth point beam 20L 2e to the seventh point beam 20L 2g .
  • the illumination of the eighth point beam 20L 2h and the ninth point beam 20L 2i causes a single peak at distance d1 to appear. From the known exit angles of the fifth point beam 20L 2e to the ninth point beam 20L 2i , the three-dimensional position of the object can be known more accurately.
  • FIG. 12 is a flow chart showing an example of operations performed by the processing circuitry 70 in measuring an object within a target scene.
  • the processing circuit 70 executes the operations of steps S201 to S207 below.
  • Processing circuitry 70 uses the wide range mode to illuminate and measure the target scene with flash light 20L2 .
  • Step S202> The processing circuit 70 determines whether an object exists at a close distance based on the measurement result in step S201.
  • the close distance is, for example, the distance from the vehicle 200 to the object of 0 m or more and 5 m or less. If the determination is Yes, processing circuit 70 performs the operation of step S203. If the determination is No, processing circuit 70 performs the operation of step S204.
  • Step S203 The processing circuit 70 transmits a collision avoidance signal to the processing circuit of the vehicle 200 . Even if it is not known where the object exists in the target scene, collision avoidance behavior such as stopping can prevent the vehicle 200 from colliding with the object.
  • Step S204> The processing circuit 70 determines whether to improve the spatial resolution in the Z direction based on the measurement result in step S201. If the determination is Yes, processing circuit 70 performs the operation of step S205. If the determination is No, processing circuit 70 performs the operation of step S201. If the object is not at close range but at close range, processing circuitry 70 may improve the spatial resolution in the Z direction. If there are no objects in the scene of interest, or if the objects are far away rather than near, the processing circuit 70 does not necessarily need to improve the spatial resolution in the Z direction.
  • Step S205> The processing circuitry 70 illuminates and measures the scene of interest with the line beam 20L2 using either the wide range mode or the narrow range mode. Processing circuitry 70 measures in a wide range mode and possibly in a narrow range mode, as shown in FIG. 7A.
  • Step S206> The processing circuit 70 determines whether to improve the spatial resolution in the Y direction based on the measurement result in step S205. If the determination is Yes, processing circuitry 70 performs the operation of step S207. If the determination is No, processing circuit 70 performs the operation of step S205. If the illumination spot of line beam 20L2 includes multiple objects, processing circuitry 70 may improve the spatial resolution in the Y direction. Otherwise, processing circuitry 70 need not necessarily improve the spatial resolution in the Y direction.
  • Processing circuitry 70 illuminates and measures the scene of interest with point beam 20L2 using wide range mode or narrow range mode. Processing circuitry 70 measures in a wide range mode and possibly in a narrow range mode, as shown in FIG. 7A.
  • FIG. 13 is a flow chart showing another example of the operation of the processing circuit 70 in scanning the target scene.
  • the processing circuit 70 executes the operations of steps S301 to S306 below.
  • Processing circuitry 70 uses the wide range mode to illuminate and measure the target scene with point beam 20L2 .
  • Step S302 The processing circuit 70 determines whether an object exists at a close distance based on the distance measurement result in step S301. If the determination is Yes, processing circuit 70 performs the operation of step S303. If the determination is No, processing circuit 70 performs the operation of step S304.
  • Step S303 The operation of step S303 is the same as the operation of step S203 shown in FIG.
  • Processing circuitry 70 determines if it is possible to measure in narrow range mode. If the determination is Yes, processing circuitry 70 performs the operation of step S306. If the determination is No, the processing circuitry 70 performs the operation of step S301.
  • Processing circuitry 70 uses the narrow range mode to illuminate the scene of interest with a point beam 20L2 to measure objects at close range.
  • FIG. 14A and 14B are diagrams showing application examples in which the measuring device according to the embodiment of the present disclosure is applied to onboard equipment.
  • Measuring device 100 is mounted on the front surface of vehicle 200 .
  • the measurement device 100 switches the measurement range according to the vehicle speed of the vehicle 200 .
  • a predetermined threshold value for example, 10 km/h
  • the measuring device 100 performs distance measurement in wide range mode.
  • the predetermined threshold for example, 10 km/h
  • the measuring device 100 performs distance measurement in the narrow range mode.
  • the criteria for switching measurement ranges are not limited to vehicle speed.
  • the measuring device 100 may measure distance in the wide range mode, and if the environment is an urban area, the measuring device 100 may measure distance in the narrow range mode.
  • the environment in which the vehicle 200 travels can be obtained from the navigation system.
  • the 15A and 15B are diagrams showing application examples in which the measuring device according to the embodiment of the present disclosure is applied to an autonomous mobile body.
  • the autonomous mobile body 300 is, for example, an AGV (Automatic Guided Vehicle) or an AGF (Automated Guided Forklift) for automatically transporting packages in a warehouse.
  • the measuring device 100 is mounted on the body of the autonomous mobile body 300 .
  • the measuring device 100 when the distance to the target object 400 is greater than or equal to a predetermined threshold value (for example, 10 m) while traveling, the measuring device 100 performs distance measurement in wide range mode.
  • a predetermined threshold value for example, 10 m
  • the measuring device 100 performs range finding in the narrow range mode. For example, if the target 400 is the charging base of the autonomous mobile body 300, the range can be measured with mm accuracy in the narrow range mode, so the autonomous mobile body 300 can be correctly connected to the charging base.
  • the operation of the measurement device 100 when switching between the wide range mode and the narrow range mode is the same as the operation shown in FIG. 7A.
  • 16A and 16B are diagrams showing application examples in which the measuring device according to the embodiment of the present disclosure is applied to a robot arm.
  • the measuring device 100 is mounted on the tip of the arm of the robot arm 500 .
  • the robot arm 500 picks up the part 600, if the distance from the tip of the arm to the object is greater than or equal to a predetermined threshold value (for example, 30 cm) as shown in FIG. I do.
  • a predetermined threshold value for example, 30 cm
  • the measuring apparatus 100 performs distance measurement in the narrow range mode.
  • the narrow range mode distance measurement with mm accuracy is possible, so the position and orientation of the component 600 can be accurately measured, and the arm can correctly pick up the component 600 .
  • the operation of the measurement device 100 when switching between the wide range mode and the narrow range mode is the same as the operation shown in FIG. 7A.
  • the switching of the measurement range is not limited to two-step switching between the narrow range mode and the wide range mode, and may be switching between three or more modes. Alternatively, the switching may be stepless.
  • the measuring device can be used, for example, for a ranging system mounted on a vehicle such as an automobile, UAV (Unmanned Aerial Vehicle), or AGV (Automated Guided Vehicle), or for vehicle detection.
  • a vehicle such as an automobile, UAV (Unmanned Aerial Vehicle), or AGV (Automated Guided Vehicle), or for vehicle detection.
  • UAV Unmanned Aerial Vehicle
  • AGV Automatic Guided Vehicle
  • object 20 light source 20L 0 laser light 20L 1 reference light 20L 2 irradiation light 20L 3 reflected light 20L 4 interference light 30 interference optical system 40 beam shaper 50 optical deflector 60 photodetector 70 processing circuit 72 memory 100 measuring device 200 vehicle

Landscapes

  • 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)
PCT/JP2022/004779 2021-03-30 2022-02-08 計測装置、およびプログラム Ceased WO2022209310A1 (ja)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP2023510588A JPWO2022209310A1 (https=) 2021-03-30 2022-02-08
CN202280020085.2A CN117015723A (zh) 2021-03-30 2022-02-08 计测装置及程序
EP22779539.0A EP4318042A4 (en) 2021-03-30 2022-02-08 MEASURING DEVICE AND PROGRAM
US18/468,720 US20240004042A1 (en) 2021-03-30 2023-09-17 Measuring device and non-transitory computer-readable medium

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021-057409 2021-03-30
JP2021057409 2021-03-30

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/468,720 Continuation US20240004042A1 (en) 2021-03-30 2023-09-17 Measuring device and non-transitory computer-readable medium

Publications (1)

Publication Number Publication Date
WO2022209310A1 true WO2022209310A1 (ja) 2022-10-06

Family

ID=83455867

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/004779 Ceased WO2022209310A1 (ja) 2021-03-30 2022-02-08 計測装置、およびプログラム

Country Status (5)

Country Link
US (1) US20240004042A1 (https=)
EP (1) EP4318042A4 (https=)
JP (1) JPWO2022209310A1 (https=)
CN (1) CN117015723A (https=)
WO (1) WO2022209310A1 (https=)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07139907A (ja) * 1993-11-12 1995-06-02 Sharp Corp レーザ測距方法および信号処理回路
JPH085733A (ja) 1994-06-22 1996-01-12 Hitachi Ltd レーダ装置
JP2002071792A (ja) 2000-08-30 2002-03-12 Hitachi Ltd レーダ装置および自動車制御システム
US20190064358A1 (en) * 2017-08-23 2019-02-28 Mezmeriz Inc. Coherent Optical Distance Measurement Apparatus and Method
WO2019130720A1 (ja) 2017-12-26 2019-07-04 パナソニックＩｐマネジメント株式会社 光スキャンデバイス、光受信デバイス、および光検出システム
US20190310372A1 (en) 2016-11-30 2019-10-10 Blackmore Sensors and Analytics Inc. Method and System for Doppler Detection and Doppler Correction of Optical Chirped Range Detection

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020018805A1 (en) * 2018-07-18 2020-01-23 Bridger Photonics, Inc. Methods and apparatuses for range peak pairing and high-accuracy target tracking using fmcw ladar measurements

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07139907A (ja) * 1993-11-12 1995-06-02 Sharp Corp レーザ測距方法および信号処理回路
JPH085733A (ja) 1994-06-22 1996-01-12 Hitachi Ltd レーダ装置
JP2002071792A (ja) 2000-08-30 2002-03-12 Hitachi Ltd レーダ装置および自動車制御システム
US20190310372A1 (en) 2016-11-30 2019-10-10 Blackmore Sensors and Analytics Inc. Method and System for Doppler Detection and Doppler Correction of Optical Chirped Range Detection
US20190064358A1 (en) * 2017-08-23 2019-02-28 Mezmeriz Inc. Coherent Optical Distance Measurement Apparatus and Method
WO2019130720A1 (ja) 2017-12-26 2019-07-04 パナソニックＩｐマネジメント株式会社 光スキャンデバイス、光受信デバイス、および光検出システム

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CHRISTOPHER V. POULTON ET AL.: "Frequency-modulated Continuous-wave LIDAR Module in Silicon Photonics", OFC2016, 2016
See also references of EP4318042A4

Also Published As

Publication number Publication date
US20240004042A1 (en) 2024-01-04
EP4318042A4 (en) 2024-09-11
JPWO2022209310A1 (https=) 2022-10-06
CN117015723A (zh) 2023-11-07
EP4318042A1 (en) 2024-02-07

Similar Documents

Publication Publication Date Title
KR101877128B1 (ko) 동적 제어를 이용한 적응형 발광 신호의 광량 제어장치
EP4256368B1 (en) Enhancement of lidar road detection
EP1966627B1 (en) Device and method for measuring relative movement
JP7762858B2 (ja) 対象物の距離および／または速度を計測する装置および方法
CN112368627B (zh) 光扫描仪
KR20180049934A (ko) 동적 제어를 이용한 적응형 수광 신호의 감도 제어장치
KR20210065259A (ko) 레이더 장치 및 그 동작 방법
US12061291B2 (en) Systems and methods for controlling laser power in light detection and ranging (LiDAR) systems
US11236988B2 (en) Laser distance measuring apparatus
WO2022209310A1 (ja) 計測装置、およびプログラム
US20220003841A1 (en) Dynamic laser power control for lidar system
US20230366984A1 (en) Dual emitting co-axial lidar system with zero blind zone
US20220334223A1 (en) Dynamic pulse control for lidar light source
WO2023220316A1 (en) Dual emitting co-axial lidar system with zero blind zone
US20250283981A1 (en) Measuring apparatus
JP2025162810A (ja) 対象物の距離および／または速度を計測する装置および方法
EP4462156A1 (en) Method and device for performing scanning fmcw lidar range measurements
WO2025169637A1 (ja) 計測装置
JP7647037B2 (ja) 投光装置、物体検出装置、移動体、投光方法及びプログラム
WO2021241101A1 (ja) 計測装置、計測装置の制御方法、およびプログラム
JP2019007892A (ja) 情報取得装置、プログラムおよび情報取得システム
WO2025154381A1 (ja) 計測装置
US20220120904A1 (en) Imaging lidar
WO2022260758A9 (en) Dynamic pulse control for lidar light source
WO2025142188A1 (ja) 計測装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22779539

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 202280020085.2

Country of ref document: CN

WWE Wipo information: entry into national phase

Ref document number: 2023510588

Country of ref document: JP

WWE Wipo information: entry into national phase

Ref document number: 2022779539

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2022779539

Country of ref document: EP

Effective date: 20231030

WWW Wipo information: withdrawn in national office

Ref document number: 2022779539

Country of ref document: EP