WO2021095601A1 - Dispositif de mesure de distance - Google Patents

Dispositif de mesure de distance Download PDF

Info

Publication number
WO2021095601A1
WO2021095601A1 PCT/JP2020/041197 JP2020041197W WO2021095601A1 WO 2021095601 A1 WO2021095601 A1 WO 2021095601A1 JP 2020041197 W JP2020041197 W JP 2020041197W WO 2021095601 A1 WO2021095601 A1 WO 2021095601A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
unit
histogram
noise floor
receiving array
Prior art date
Application number
PCT/JP2020/041197
Other languages
English (en)
Japanese (ja)
Inventor
善英 立野
Original Assignee
株式会社デンソー
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 株式会社デンソー filed Critical 株式会社デンソー
Publication of WO2021095601A1 publication Critical patent/WO2021095601A1/fr

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
    • 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
    • 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
    • G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
    • G01S17/894—3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
    • 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
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/487—Extracting wanted echo signals, e.g. pulse detection

Definitions

  • the present disclosure relates to a distance measuring device that irradiates light and measures the distance to an object that reflects the light.
  • Patent Document 1 describes a distance for measuring the time from irradiation to light reception by irradiating light and receiving reflected light from an object, and measuring the distance to an object that reflects light based on this time. It is described that a measuring device uses a plurality of avalanche photodiodes operating in Geiger mode to detect light.
  • This disclosure improves the accuracy of distance measurement.
  • One aspect of the present disclosure is a distance measuring device including an irradiation unit, a light receiving array unit, a histogram creation unit, a noise floor calculation unit, a variation calculation unit, a threshold value calculation unit, and a distance calculation unit.
  • the irradiation unit is configured to irradiate pulsed pulsed light.
  • the light receiving array unit includes a plurality of photodetectors that output a pulse signal when a photon is incident.
  • the histogram creation unit is configured to create a histogram showing the time change of the amount of light received by the light receiving array unit according to a plurality of pulse signals output from the light receiving array unit.
  • the noise floor calculation unit is configured to calculate the background light noise floor indicating the light reception level of the background light detected by the light receiving array unit based on the histogram created by the histogram creation unit.
  • the variation calculation unit is configured to calculate a variation parameter indicating the degree of variation in the background light noise floor based on the histogram created by the histogram creation unit.
  • the threshold value calculation unit detects the pulsed light emitted by the irradiation unit in the histogram based on the background light noise floor calculated by the noise floor calculation unit and the variation parameter calculated by the variation calculation unit. It is configured to calculate a threshold for determining whether or not.
  • the distance calculation unit is configured to calculate the distance to the object that reflected the pulsed light based on the threshold value calculated by the threshold value calculation unit.
  • the distance measuring device of the present disclosure configured in this way calculates a threshold value based on the background light noise floor and the variation parameter of the background light noise floor. Therefore, the distance measuring device of the present disclosure can change the threshold value according to the magnitude of the variation of the background light noise floor (that is, the magnitude of the standard deviation of the background light noise floor). As a result, the distance measuring device of the present disclosure may erroneously detect the background light as pulsed light reflected by an object (hereinafter referred to as reflected light), or may not be able to detect the reflected light from the object. Can be suppressed and the distance measurement accuracy can be improved.
  • the distance measuring device 1 of the present embodiment is mounted on a vehicle and measures the distance to various objects existing around the vehicle.
  • the distance measuring device 1 includes an irradiation unit 2, a light receiving array unit 3, a counting unit 4, and a signal processing unit 5.
  • the irradiation unit 2 repeatedly irradiates the pulsed laser beam at preset intervals, and notifies the counting unit 4 and the signal processing unit 5 of the irradiation timing.
  • the cycle of irradiating the laser beam is referred to as a measurement cycle.
  • the light receiving array unit 3 has a plurality of pixel units P1, P2, ..., Pk. k is an integer greater than or equal to 2.
  • Each pixel unit Pi includes N photodetectors 31. N is an integer greater than or equal to 2. When a photon is incident, the photodetector 31 outputs a pulse signal having a preset pulse width.
  • the counting unit 4 includes a plurality of adders A1, A2, ..., Ak and a plurality of histogram memories M1, M2, ..., Mk.
  • the adders A1, A2, ..., Ak are connected to the pixel units P1, P2, ..., Pk, respectively.
  • the adder Ai outputs an adder signal indicating the total value (hereinafter, the number of pulse inputs) of the pulse signals input from the N photodetectors 31 constituting the pixel unit Pi. i is an integer from 1 to k.
  • Histogram memories M1, M2, ..., Mk are connected to adders A1, A2, ..., Ak, respectively. Then, the histogram memory Mi sets the number of pulse inputs indicated by the addition signal input from the adder Ai to the latest each time a preset acquisition cycle elapses starting from the latest irradiation timing notified from the irradiation unit 2. It is stored in association with the number of times the acquisition cycle has arrived from the irradiation timing of. Further, the histogram memories M1, M2, ..., Mk are connected to the signal processing unit 5.
  • the signal processing unit 5 is an electronic control device mainly composed of a microcomputer equipped with a CPU 51, a ROM 52, a RAM 53, and the like.
  • Various functions of the microcomputer are realized by the CPU 51 executing a program stored in a non-transitional substantive recording medium.
  • the ROM 52 corresponds to a non-transitional substantive recording medium in which the program is stored.
  • the method corresponding to the program is executed.
  • a part or all of the functions executed by the CPU 51 may be configured in hardware by one or a plurality of ICs or the like. Further, the number of microcomputers constituting the signal processing unit 5 may be one or a plurality.
  • the light receiving array unit 3 includes a light receiving surface 3a formed by arranging a plurality of pixel units P1, P2, ..., Pk in a two-dimensional matrix.
  • the photodetector 31 includes a SPAD 61, a quench resistor 62, an inverting circuit 63, a D flip-flop circuit (hereinafter, DFF circuit) 64, and a delay circuit 65.
  • SPAD is an abbreviation for Single Photon Avalanche Diode.
  • SPAD61 is an avalanche photodiode that operates in Geiger mode and can detect the incident of a single photon.
  • the anode is connected to the negative power supply and the cathode is connected to the positive power supply via the quench resistor 62.
  • the quench resistor 62 applies a reverse bias voltage to the SPAD 61. Further, the quench resistor 62 stops the Geiger discharge of the SPAD 61 by the voltage drop generated by the current flowing through the SPAD 61 when the photon is incident on the SPAD 61 and the SPAD 61 is broken down.
  • the quench resistance 62 a resistance element having a predetermined resistance value, a MOSFET whose on-resistance can be set by the gate voltage, or the like is used.
  • An inverting circuit 63 is connected to the cathode of the SPAD61.
  • the input of the inverting circuit 63 is at a high level.
  • a current flows through the quench resistor 62, so that the input of the inverting circuit 63 changes to a low level.
  • the DFF circuit 64 the output of the inverting circuit 63 changes to a high level at a rising edge where the output changes from a low level to a high level.
  • the output of the DFF circuit 64 is connected to the reset terminal of the DFF circuit 64 via the delay circuit 65.
  • the delay circuit 65 causes the output of the DFF circuit 64 to be input to the reset terminal by inverting the signal level and delaying the output by a preset delay time. As a result, the output of the DFF circuit 64 changes to the low level by resetting the DFF circuit 64 when the delay time elapses after changing to the high level.
  • the pixel histogram created by the stored data stored in the histogram memory Mi has the time starting from the latest irradiation timing as the horizontal axis and the number of pulse inputs as the vertical axis, and the number of pulse inputs. It is a histogram showing the time change.
  • the maximum value on the vertical axis is N.
  • the pixel histogram shows the number of pulse inputs for each time bin Tbin.
  • the time bin Tbin is a time range that serves as a unit scale of the pixel histogram.
  • the length of the time bin Tbin is equal to the acquisition cycle described above.
  • the time bin Tbin is numbered 1, 2, 3, ... In order from the latest irradiation timing.
  • the time bin Tbin whose identification number is from 1 to m corresponds to the background light noise floor calculation period Tb.
  • the time bin Tbin whose identification number is (m + 1) or later corresponds to the distance calculation period Tr.
  • m is an integer of 2 or more.
  • the heights of bars B1, B2, and B3 in the pixel histogram shown in FIG. 3 indicate the number of pulse inputs due to the light reflected by the object and the background light.
  • the heights of the bars other than the bars B1, B2, and B3 indicate the number of pulse inputs by the background light.
  • the distance measurement process is a process that is repeatedly executed every time the measurement cycle elapses when the irradiation unit 2 is irradiating the laser beam.
  • the CPU 51 stores 1 in the pixel indicated value i provided in the RAM 53 in S10 as shown in FIG.
  • the CPU 51 acquires the stored data from the histogram memory Mi in S20.
  • the CPU 51 creates a pixel histogram of the i-th pixel unit Pi using the stored data acquired in S20 in S30.
  • the CPU 51 calculates the background light noise floor BGND in S40.
  • the background light noise floor is a light receiving level of light (that is, background light) detected by the light receiving array unit 3 when the laser light emitted from the irradiation unit 2 is not received by the light receiving array unit 3.
  • the CPU 51 calculates the background light noise floor BGND by the following equation (1), where the number of pulse inputs corresponding to the time bin Tbin whose identification number is j is BGND_j.
  • the CPU 51 calculates the background light standard deviation ⁇ _BGND in S50 by the following equation (2).
  • the parameters of the photodetector 31 used in the background light standard deviation ⁇ _BGND are theoretically based on the definition formula of the binomial distribution.
  • the probability density function of the binomial distribution determined by the two parameters n and p is expressed by the following equation (3).
  • the following equation (3) shows the probability of success k times when an independent Bernoulli trial with a success probability p is tried n times.
  • the response probability p of one SPAD61 is expressed by the following equation (7).
  • the number of trials n is expressed by the following equation (8).
  • r is the ideal count rate
  • ⁇ P is the dead time of SPAD61
  • A is the number of SPADs responded (that is, the expected value of background light)
  • N is per pixel. The number of SPADs.
  • the response probability p of one SPAD61 can be replaced with "the probability that A SPAD61 out of N SPAD61 will respond".
  • Equation (1) shows the average value of the number of pulse inputs in the time bin Tbin whose identification number is from 1 to m, and equation (1) corresponds to the following equation (9).
  • the standard deviation ⁇ [X] is expressed by the following equation (10).
  • the standard deviation ⁇ [X] represented by the following equation (10) corresponds to the background light standard deviation ⁇ _BGND represented by the equation (2).
  • the CPU 51 calculates the threshold value Th by the following equation (11) in S60.
  • a in the following equation (11) is a preset false positive tolerance coefficient. The larger the erroneous detection tolerance coefficient a, the less frequently the background light is erroneously detected as the detection of the light reflected by the object.
  • the curve D1 shown in FIG. 3 shows a normal distribution in which the average value is the background light noise floor BGND and the standard deviation is the background light standard deviation ⁇ _BGND.
  • the CPU 51 calculates the distance to the object that reflects light (hereinafter, the object distance) by using the pixel histogram created in S30 and the threshold value Th calculated in S60 in S70.
  • the CPU 51 first transitions from a state in which the number of pulse inputs is less than the threshold value Th to a state in which the number of pulse inputs is greater than or equal to the threshold value Th in the distance calculation period Tr.
  • the time bin Tbin is specified as the rise time bin.
  • the time bin Tbin corresponding to the bar B1 is the rise time bin.
  • the CPU 51 specifies the time bin Tbin at the time of transition from the state where the number of pulse inputs is equal to or more than the threshold value Th to the state where the number of pulse inputs is less than the threshold value Th in the distance calculation period Tr as the fall time bin.
  • the time bin Tbin corresponding to the bar B4 is the fall time bin.
  • the CPU 51 calculates as a signal detection time an intermediate time between the rise time corresponding to the rise time bin and the fall time corresponding to the fall time bin.
  • the time Tu from the irradiation timing to the time bin Tbin corresponding to the bar B1 is the rise time
  • the time Td from the irradiation timing to the time bin Tbin corresponding to the bar B4 is the fall time. ..
  • the CPU 51 calculates the object distance based on the calculated signal detection time.
  • the CPU 51 determines in S80 whether or not the value stored in the pixel indicated value i is the total number of pixels k or more.
  • the CPU 51 adds 1 to the value stored in the pixel indicated value i in S90. It is stored in the pixel indicated value i and shifts to S20.
  • the CPU 51 ends the distance measurement process.
  • the distance measuring device 1 configured in this way includes an irradiation unit 2, a light receiving array unit 3, a counting unit 4, and a signal processing unit 5.
  • the irradiation unit 2 irradiates a pulsed pulsed light.
  • the light receiving array unit 3 includes a plurality of photodetectors 31 that output a pulse signal when a photon is incident.
  • the counting unit 4 and the signal processing unit 5 create a pixel histogram showing the time change of the amount of light received by the light receiving array unit 3 according to the plurality of pulse signals output from the light receiving array unit 3.
  • the signal processing unit 5 calculates the background light noise floor BGND indicating the light receiving level of the background light detected by the light receiving array unit 3 based on the created pixel histogram.
  • the signal processing unit 5 calculates the light reception level of the light detected by the light receiving array unit 3 when the pulsed light irradiated by the irradiation unit 2 is not received by the light receiving array unit 3 as the background light noise floor BGND. ..
  • the signal processing unit 5 calculates the background light standard deviation ⁇ _BGND based on the created pixel histogram. Whether the signal processing unit 5 has detected the pulsed light emitted by the irradiation unit 2 in the pixel histogram based on the calculated background light noise floor BGND and the calculated background light standard deviation ⁇ _BGND by the light receiving array unit 3.
  • the threshold value Th for determining whether or not to use is calculated.
  • the signal processing unit 5 calculates the distance to the object that reflected the pulsed light based on the calculated threshold value Th.
  • the distance measuring device 1 calculates the threshold value Th based on the background light noise floor BGND and the background light standard deviation ⁇ _BGND. Therefore, the distance measuring device 1 can change the threshold value Th according to the magnitude of the variation of the background light noise floor BGND (that is, the magnitude of the background light standard deviation ⁇ _BGND). As a result, the distance measuring device 1 suppresses the occurrence of a situation in which the background light is erroneously detected as pulsed light reflected by an object (hereinafter referred to as reflected light) or the reflected light from the object cannot be detected. However, the distance measurement accuracy can be improved.
  • the light receiving array unit 3 is configured such that a plurality of photodetectors 31 form one pixel, and includes k pixels.
  • the signal processing unit 5 calculates the background light standard deviation ⁇ _BGND based on the calculated background light noise floor BGND and the number N of the photodetectors 31 constituting one pixel. As a result, the distance measuring device 1 can easily calculate the background light standard deviation ⁇ _BGND, and the processing load of the signal processing unit 5 can be reduced.
  • the counting unit 4, S20, and S30 correspond to the processing as the histogram creation unit
  • the pixel histogram corresponds to the histogram
  • S40 corresponds to the processing as the noise floor calculation unit
  • S50 corresponds to the variation calculation. It corresponds to the processing as a part
  • the background light standard deviation ⁇ _BGND corresponds to the variation parameter.
  • S60 corresponds to the processing as the threshold value calculation unit
  • S70 corresponds to the processing as the distance calculation unit
  • the pixel unit Pi corresponds to the pixel.
  • the distance measuring device 1 of the second embodiment is different from the first embodiment in that the distance measuring process is changed.
  • the CPU 51 adds 1 to the value stored in the addition number count provided in the RAM 53 in S210 as shown in FIG. Store in the count of additions.
  • the CPU 51 acquires stored data from all the histogram memories M1, M2, ..., Mk in S220.
  • the CPU 51 creates integrated pixel histograms of all the pixel units P1, P2, ..., Pk in S230 using the stored data acquired in S220.
  • the CPU 51 first creates a pixel histogram of the pixel unit P1 using the stored data of the histogram memory M1 acquired in S220. Then, the CPU 51 adds the pixel histogram of the created pixel unit P1 to the integrated pixel histogram of the pixel unit P1 stored in the RAM 53. That is, the CPU 51 adds the number of pulse inputs of the time bin Tbin having the same identification number to the pixel histogram of the pixel unit P1 and the integrated pixel histogram of the pixel unit P1, and uses this added value as the new integrated pixel histogram. Let it be the number of pulse inputs. Then, the CPU 51 stores in the RAM 53 a new integrated pixel histogram created for the pixel unit P1. When the integrated pixel histogram of the pixel unit P1 is not stored in the RAM 53, the CPU 51 stores the created pixel histogram of the pixel unit P1 in the RAM 53 as a new integrated pixel histogram.
  • the CPU 51 also creates an integrated pixel histogram for the pixel units P2, ..., Pk in the same manner as the pixel unit P1 and stores them in the RAM 53.
  • the CPU 51 determines whether or not the value stored in the addition count Count is equal to or greater than the upper limit number n. Here, if the value stored in the addition count is less than the upper limit n, the CPU 51 ends the distance measurement process.
  • the CPU 51 stores 0 in the addition count Count in S250.
  • an integrated pixel histogram is created by repeating the upper limit number of times n and adding the pixel histograms.
  • the integrated pixel histograms of all the pixel units P1, P2, ..., Pk have pulse inputs with the time starting from the irradiation timing as the horizontal axis and the number of pulse inputs as the vertical axis. It is a histogram which shows the time change of the number.
  • the maximum value on the vertical axis is N ⁇ n.
  • the integrated pixel histogram shows the number of pulse inputs for each time bin Tbin.
  • the time bins Tbin are numbered 1, 2, 3, ... In order from the latest irradiation timing.
  • the time bin Tbin whose identification number is from 1 to m corresponds to the background light noise floor calculation period Tb.
  • the time bin Tbin whose identification number is (m + 1) or later corresponds to the distance calculation period Tr.
  • m is an integer of 2 or more.
  • the heights of bars B11, B12, and B13 in the pixel histogram shown in FIG. 6 indicate the number of pulse inputs due to the light reflected by the object and the background light.
  • the heights of the bars other than the bars B11, B12, and B13 indicate the number of pulse inputs by the background light.
  • the CPU 51 stores 1 in the pixel indicated value i provided in the RAM 53 in S260 as shown in FIG.
  • the CPU 51 acquires the integrated pixel histogram of the pixel unit Pi from the RAM 53 in S270.
  • the CPU 51 calculates the background light noise floor BGND_n of the integrated pixel histogram of the pixel unit Pi in S280. Specifically, the CPU 51 calculates the background light noise floor BGND_n by the following equation (12), where the number of pulse inputs corresponding to the time bin Tbin whose identification number is j is BGND_n_j.
  • the CPU 51 calculates the background light standard deviation ⁇ _BGND_n in S290 by the following equation (13).
  • the number of trials n is expressed by the following equation (14).
  • the Count in the formula (14) is the number of additions described above.
  • Equation (12) shows the average value of the number of pulse inputs in the time bin Tbin whose identification number is from 1 to m, and equation (12) corresponds to the following equation (15).
  • the standard deviation ⁇ [X] is expressed by the following equation (16).
  • the standard deviation ⁇ [X] represented by the following equation (16) corresponds to the background light standard deviation ⁇ _BGND_n represented by the equation (13).
  • the CPU 51 calculates the threshold value Th_n in S300 by the following equation (17).
  • the curve D2 shown in FIG. 6 shows a normal distribution in which the average value is the background light noise floor BGND_n and the standard deviation is the background light standard deviation ⁇ _BGND_n.
  • the CPU 51 calculates the object distance in S310 by using the integrated pixel histogram of the pixel unit Pi acquired in S270 and the threshold value Th_n calculated in S300.
  • the CPU 51 first transitions from a state in which the number of pulse inputs is less than the threshold value Th_n to a state in which the number of pulse inputs is greater than or equal to the threshold value Th_n in the distance calculation period Tr.
  • the time bin Tbin is specified as the rise time bin.
  • the time bin Tbin corresponding to the bar B11 is the rise time bin.
  • the CPU 51 specifies the time bin Tbin when the number of pulse inputs is less than the threshold Th_n from the state where the number of pulse inputs is less than the threshold Th_n in the distance calculation period Tr as the fall time bin.
  • the time bin Tbin corresponding to the bar B14 is the fall time bin.
  • the CPU 51 calculates as a signal detection time an intermediate time between the rise time corresponding to the rise time bin and the fall time corresponding to the fall time bin.
  • the time Tu from the irradiation timing to the time bin Tbin corresponding to the bar B11 is the rise time
  • the time Td from the irradiation timing to the time bin Tbin corresponding to the bar B14 is the fall time. is there.
  • the CPU 51 calculates the object distance based on the calculated signal detection time.
  • the CPU 51 determines in S320 whether or not the value stored in the pixel indicated value i is the total number of pixels k or more.
  • the CPU 51 adds 1 to the value stored in the pixel indicated value i in S330. It is stored in the pixel indicated value i and shifts to S270.
  • the CPU 51 in S340 when the value stored in the pixel indicated value i is the total number of pixels k or more, the CPU 51 in S340, all the pixel units P1, P2, ..., Pk stored in the RAM 53. The integrated pixel histogram of the above is erased from the RAM 53, and the distance measurement process is completed.
  • the distance measuring device 1 configured in this way includes an irradiation unit 2, a light receiving array unit 3, a counting unit 4, and a signal processing unit 5.
  • the irradiation unit 2 irradiates a pulsed pulsed light.
  • the light receiving array unit 3 includes a plurality of photodetectors 31 that output a pulse signal when a photon is incident.
  • the counting unit 4 and the signal processing unit 5 create an integrated pixel histogram showing the time change of the amount of light received by the light receiving array unit 3 according to the plurality of pulse signals output from the light receiving array unit 3.
  • the counting unit 4 and the signal processing unit 5 detect n times obtained by executing the light detection operation n times from the irradiation unit 2 irradiating the pulsed light to the light receiving array unit 3 detecting the pulsed light. By integrating the results, an integrated pixel histogram is created.
  • the signal processing unit 5 calculates the background light noise floor BGND_n indicating the light receiving level of the background light detected by the light receiving array unit 3 based on the created integrated pixel histogram.
  • the signal processing unit 5 calculates the background light standard deviation ⁇ _BGND_n based on the created integrated pixel histogram. Based on the calculated background light noise floor BGND_n and the calculated background light standard deviation ⁇ _BGND_n, the signal processing unit 5 detected the pulsed light emitted by the irradiation unit 2 in the integrated pixel histogram in the light receiving array unit 3. The threshold value Th_n for determining whether or not it is calculated is calculated.
  • the signal processing unit 5 calculates the distance to the object that reflected the pulsed light based on the calculated threshold value Th_n.
  • the distance measuring device 1 calculates the threshold value Th_n based on the background light noise floor BGND_n and the background light standard deviation ⁇ _BGND_n. Therefore, the distance measuring device 1 can change the threshold value Th_n according to the magnitude of the variation of the background light noise floor BGND_n (that is, the magnitude of the background light standard deviation ⁇ _BGND_n). As a result, the distance measuring device 1 can improve the distance measurement accuracy by suppressing the occurrence of a situation in which the background light is erroneously detected as the reflected light or the reflected light from the object cannot be detected. it can.
  • the light receiving array unit 3 is configured such that a plurality of photodetectors 31 form one pixel, and includes k pixels.
  • the signal processing unit 5 obtains the calculated background light noise floor BGND_n, the number N of the photodetectors 31 constituting one pixel, and the detection result of n times obtained by executing the light detection operation n times.
  • the background light standard deviation ⁇ _BGND_n is calculated based on the number of integrations n of the integrated pixel histogram created by the integration. As a result, the distance measuring device 1 can easily calculate the background light standard deviation ⁇ _BGND_n, and can reduce the processing load of the signal processing unit 5.
  • the distance measuring device 1 creates an integrated pixel histogram by integrating n pixel histograms. By increasing the number of pulsed lights used in one distance measurement in this way, the SN ratio in the integrated pixel histogram can be improved, and the distance measurement accuracy can be further improved.
  • the counting unit 4 and S210 to S250 correspond to the processing as the histogram creation unit
  • the integrated pixel histogram corresponds to the histogram
  • S280 corresponds to the processing as the noise floor calculation unit
  • S290 varies. It corresponds to the processing as a calculation unit
  • the background light standard deviation ⁇ _BGND_n corresponds to the variation parameter.
  • S300 corresponds to the processing as the threshold value calculation unit
  • S310 corresponds to the processing as the distance calculation unit.
  • the distance measuring device 1 of the third embodiment is different from the second embodiment in that the distance measuring process is changed.
  • the distance measurement process of the third embodiment is different from the second embodiment in that the process of S305 is executed instead of S300.
  • the CPU 51 calculates the threshold Th_n in S305 with reference to the threshold table TB1 stored in the ROM 52, and shifts to S310.
  • the threshold table TB1 sets the correspondence between the background light noise floor BGND_n and the threshold Th_n. Specifically, the threshold table TB1 stores the thresholds Th_n when the background light noise floor BGND_n is 0, 1, ..., N ⁇ n as the thresholds th_BGND_0, th_BGND_1, ..., th_BGND_N ⁇ n, respectively. To do.
  • the threshold value th_BGND_x is a value calculated by the following equation (18). x is an integer from 0 to N ⁇ n.
  • S305 corresponds to the processing as the threshold value calculation unit.
  • the background light noise floors BGND and BGND_n are calculated as the average value of the number of pulse inputs in the background light noise floor calculation period Tb.
  • the background light noise floors BGND and BGND_n may be calculated as the median number of pulse inputs in the background light noise floor calculation period Tb.
  • the threshold value Th_n is calculated with reference to the threshold value table TB1.
  • the threshold value Th of the first embodiment may be calculated by referring to the threshold value table TB2 shown in FIG.
  • the threshold table TB2 sets the correspondence between the background light noise floor BGND and the threshold Th.
  • the threshold table TB1 stores the threshold Th when the background light noise floor BGND is 0, 1, ..., N as the thresholds th_BGND_0, th_BGND_11, ..., th_BGND_N, respectively.
  • the threshold value th_BGND_y is a value calculated by the following equation (19). y is an integer from 0 to N.
  • the background light noise floors BGND and BGND_n are calculated based on the number of pulse inputs in the background light noise floor calculation period Tb.
  • the background light noise floors BGND and BGND_n may be calculated by also using the number of pulse inputs in the distance calculation period Tr.
  • the signal processing unit 5 and its method described in the present disclosure are provided by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. , May be realized.
  • the signal processing unit 5 and its method described in the present disclosure may be realized by a dedicated computer provided by configuring the processor with one or more dedicated hardware logic circuits.
  • the signal processing unit 5 and its method described in the present disclosure include a processor and memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. It may be realized by one or more dedicated computers configured by a combination.
  • the computer program may also be stored on a computer-readable non-transitional tangible recording medium as an instruction executed by the computer.
  • the method for realizing the functions of each unit included in the signal processing unit 5 does not necessarily include software, and all the functions may be realized by using one or a plurality of hardware.
  • a plurality of functions possessed by one component in the above embodiment may be realized by a plurality of components, or one function possessed by one component may be realized by a plurality of components. Further, a plurality of functions possessed by the plurality of components may be realized by one component, or one function realized by the plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. In addition, at least a part of the configuration of the above embodiment may be added or replaced with the configuration of the other above embodiment.
  • a system having the distance measuring device 1 as a component, a program for operating a computer as the distance measuring device 1, a non-transitional substantive record such as a semiconductor memory in which this program is recorded In addition to the above-mentioned distance measuring device 1, a system having the distance measuring device 1 as a component, a program for operating a computer as the distance measuring device 1, a non-transitional substantive record such as a semiconductor memory in which this program is recorded.
  • the present disclosure can also be realized in various forms such as a medium and a distance measuring method.

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)

Abstract

L'invention concerne un dispositif de mesure de distance (1) comprenant une unité d'irradiation (2), une unité de réseau de réception de lumière (3), des unités de création d'histogramme (4, S20, S30, S210-S250), des unités de calcul de bruit de fond CME (S40, S280), des unités de calcul de variation (S50, S290) et des unités de calcul de valeur de seuil (S60, S300, S305). Les unités de création d'histogramme créent des histogrammes qui indiquent le changement dans le temps de la quantité de lumière reçue par l'unité de réseau de réception de lumière. Les unités de calcul de bruit de fond CME calculent un bruit de fond CME de lumière de fond indiquant le niveau de réception de lumière pour la lumière de fond détectée par l'unité de réseau de réception de lumière. Les unités de calcul de variation calculent des paramètres de variation indiquant des degrés de variation du bruit de fond CME de lumière de fond. Les unités de calcul de valeur de seuil calculent une valeur de seuil pour déterminer si une lumière pulsée a été détectée dans l'histogramme par l'unité de réseau de réception de lumière.
PCT/JP2020/041197 2019-11-12 2020-11-04 Dispositif de mesure de distance WO2021095601A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2019204613A JP7388141B2 (ja) 2019-11-12 2019-11-12 距離測定装置
JP2019-204613 2019-11-12

Publications (1)

Publication Number Publication Date
WO2021095601A1 true WO2021095601A1 (fr) 2021-05-20

Family

ID=75897569

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2020/041197 WO2021095601A1 (fr) 2019-11-12 2020-11-04 Dispositif de mesure de distance

Country Status (2)

Country Link
JP (1) JP7388141B2 (fr)
WO (1) WO2021095601A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114114300B (zh) * 2022-01-25 2022-05-24 深圳市灵明光子科技有限公司 一种散点重分布测距装置和激光探测系统

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010091377A (ja) * 2008-10-07 2010-04-22 Toyota Motor Corp 光学式測距装置及び方法
JP2012037267A (ja) * 2010-08-04 2012-02-23 Hitachi High-Technologies Corp 光量検出方法及びその装置
JP2016161438A (ja) * 2015-03-03 2016-09-05 株式会社デンソー 演算装置
US20170176578A1 (en) * 2015-12-18 2017-06-22 Stmicroelectronics (Research & Development) Limited Ranging apparatus
CN107015234A (zh) * 2017-05-19 2017-08-04 中国科学院国家天文台长春人造卫星观测站 嵌入式卫星激光测距控制系统
JP2018091760A (ja) * 2016-12-05 2018-06-14 株式会社豊田中央研究所 光学測定装置、光学測定方法、及び光学測定プログラム
JP2019100919A (ja) * 2017-12-05 2019-06-24 シャープ株式会社 受光素子、飛行時間測定装置及び光レーダー装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010091377A (ja) * 2008-10-07 2010-04-22 Toyota Motor Corp 光学式測距装置及び方法
JP2012037267A (ja) * 2010-08-04 2012-02-23 Hitachi High-Technologies Corp 光量検出方法及びその装置
JP2016161438A (ja) * 2015-03-03 2016-09-05 株式会社デンソー 演算装置
US20170176578A1 (en) * 2015-12-18 2017-06-22 Stmicroelectronics (Research & Development) Limited Ranging apparatus
JP2018091760A (ja) * 2016-12-05 2018-06-14 株式会社豊田中央研究所 光学測定装置、光学測定方法、及び光学測定プログラム
CN107015234A (zh) * 2017-05-19 2017-08-04 中国科学院国家天文台长春人造卫星观测站 嵌入式卫星激光测距控制系统
JP2019100919A (ja) * 2017-12-05 2019-06-24 シャープ株式会社 受光素子、飛行時間測定装置及び光レーダー装置

Also Published As

Publication number Publication date
JP2021076517A (ja) 2021-05-20
JP7388141B2 (ja) 2023-11-29

Similar Documents

Publication Publication Date Title
CN109100702B (zh) 用于测量到对象的距离的光电传感器和方法
JP6863342B2 (ja) 光測距装置
US10612973B2 (en) Light detection device
US11668826B2 (en) Photodetector
US10304877B2 (en) Circuit and method for controlling and selectively enabling photodiode cells
JP6443132B2 (ja) 演算装置
JP6849125B2 (ja) 光計測装置
CN110622038B (zh) 光传感器、电子设备、运算装置及对光传感器与检测对象物之间的距离进行测量的方法
JP7501289B2 (ja) 距離測定装置
JP2020112443A (ja) 距離測定装置及び距離測定方法
JP7180398B2 (ja) 光測距装置およびその制御方法
WO2021095601A1 (fr) Dispositif de mesure de distance
CN116338711A (zh) 光学测量装置
WO2019050024A1 (fr) Procédé de mesure de distance et dispositif de mesure de distance
KR102198941B1 (ko) TOF(Time of Flight)를 이용한 거리 측정 장치 및 방법
KR20230113154A (ko) 측정 장치 및 측정 방법
CN113614566B (zh) 测距方法、测距装置以及程序记录介质
CN110799854B (zh) 光测距装置
JP2017003489A (ja) レーザレーダ装置
US20240210532A1 (en) Optoelectronic device with time-of-flight sensor using dynamic time windows
US20240125933A1 (en) Ranging device
US20240036198A1 (en) Optical Ranging Device
US20240022831A1 (en) Ranging device
US20230057944A1 (en) Image capturing apparatus having photon detection and control method therefor
Ma et al. Modeling and Analysis of Noise Reduction Method in SPAD-Based LiDAR System

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: 20886890

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20886890

Country of ref document: EP

Kind code of ref document: A1