WO2021248292A1 - 基于飞行时间的测距方法和相关测距系统 - Google Patents

基于飞行时间的测距方法和相关测距系统 Download PDF

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Publication number
WO2021248292A1
WO2021248292A1 PCT/CN2020/095029 CN2020095029W WO2021248292A1 WO 2021248292 A1 WO2021248292 A1 WO 2021248292A1 CN 2020095029 W CN2020095029 W CN 2020095029W WO 2021248292 A1 WO2021248292 A1 WO 2021248292A1
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sampling
time
pulse
signal
flight
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PCT/CN2020/095029
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English (en)
French (fr)
Inventor
杨孟达
李宗德
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深圳市汇顶科技股份有限公司
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Priority to PCT/CN2020/095029 priority Critical patent/WO2021248292A1/zh
Priority to EP20922497.1A priority patent/EP3951432A4/en
Priority to US17/468,062 priority patent/US20210405162A1/en
Publication of WO2021248292A1 publication Critical patent/WO2021248292A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/486—Receivers
    • G01S7/4861—Circuits for detection, sampling, integration or read-out
    • 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
    • G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
    • 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
    • G01S7/4868—Controlling received signal intensity or exposure of sensor
    • 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
    • G01S7/4861—Circuits for detection, sampling, integration or read-out
    • G01S7/4863—Detector arrays, e.g. charge-transfer gates

Definitions

  • This application relates to distance measurement and depth sensing technology, and more particularly to a distance measurement method based on flight time, and a related distance measurement system.
  • pulse modulation measures the distance of the target through the time difference between the transmission and reception of optical pulses, and has a relatively simple measurement mechanism. Pulse modulation has higher requirements for time measurement accuracy.
  • high dynamic range the existing technology still has considerable room for improvement in the range that can be covered by the distance measurement and the degree of influence of the remote information on the background light. .
  • An embodiment of the present application discloses a time-of-flight-based ranging method, including: intermittently sending a plurality of first pulses from a pulse generating unit, wherein the plurality of first pulses are reflected by a target to generate a plurality of first pulses.
  • a first reflection signal enabling the time-of-flight sensor to selectively perform first signal sampling or second signal sampling on the plurality of first reflection signals to generate a first sampling result, wherein the start time point of the first signal sampling There is a first time difference with the corresponding sending time point of the first pulse, and the first signal sampling lasts for a first predetermined time, and the start time point of the second signal sampling and the corresponding first pulse
  • the sending time point has a second time difference, and the second signal sampling lasts for a second predetermined time, and the first time difference is smaller than the second time difference; according to the first sampling result, the multiple first pulses are detected
  • the flight time from the pulse generating unit to the flight time sensor; and the distance between the target and the reference position is determined according to the flight time.
  • a time-of-flight-based ranging system including: a pulse generating unit; a control circuit, coupled to the pulse generating unit, for controlling the pulse generating unit to intermittently send multiple First pulses, wherein the plurality of first pulses are reflected by the target to generate a plurality of first reflection signals; and a time-of-flight sensor, which is controlled by the control circuit, is configured to respond to the plurality of first reflection signals Respectively selectively performing first signal sampling or second signal sampling to generate a first sampling result, wherein the start time point of the first signal sampling and the corresponding sending time point of the first pulse have a first time difference, and The first signal sampling lasts for a first predetermined time, and the start time point of the second signal sampling and the corresponding sending time point of the first pulse have a second time difference, and the first time difference is less than the first time difference.
  • the second signal sampling lasts for a second predetermined time, and according to the first sampling result, detecting the flight time of the plurality of first pulses from the pulse generating unit to the flight time sensor, and The distance between the target object and the reference position is determined according to the flight time.
  • Yet another embodiment of the present application discloses a time-of-flight-based ranging method, including: intermittently sending a plurality of pulse groups from a pulse generating unit, wherein each pulse group includes a first pulse and a second pulse. The intensity of the first pulse and the intensity of the second pulse are different, and the multiple pulse groups are reflected by the target to generate multiple reflected signal groups; the time-of-flight sensor is made to perform signal sampling on the multiple reflected signal groups respectively To generate a sampling result, wherein the signal sampling lasts for a predetermined time; according to the sampling result, detecting the flight time of the plurality of pulse groups from the pulse generating unit to the flight time sensor; and measuring according to the flight time The distance between the target and the reference position.
  • a time-of-flight-based ranging system including: a pulse generating unit; a control circuit, coupled to the pulse generating unit, for controlling the pulse generating unit to intermittently send A plurality of pulse groups, wherein each pulse group includes a first pulse and a second pulse, the intensity of the first pulse and the intensity of the second pulse are different, and the plurality of pulse groups are reflected by the target to generate a plurality of A reflection signal group; and a time-of-flight sensor, controlled by the control circuit, for performing signal sampling on the multiple reflection signal groups to generate sampling results, wherein the signal sampling lasts for a predetermined time; the time-of-flight sensor The flight time of the plurality of pulse groups from the pulse generating unit to the flight time sensor is also detected according to the sampling result, and the distance between the target and the ranging system is measured according to the flight time .
  • the time-of-flight-based ranging method and related ranging system disclosed in the present application can improve the performance of high dynamic range sampling by adjusting the sampling interval or pulse pattern.
  • Fig. 1 is a functional block diagram of an embodiment of a distance measurement system based on flight time according to the present application.
  • FIG. 2 is a schematic diagram of an embodiment of the circuit structure of a single pixel in the pixel array of the distance measuring system shown in FIG. 1.
  • FIG. 3 is a schematic diagram of an embodiment of signal timing related to the pixel shown in FIG. 2.
  • FIG. 4 is a schematic diagram of another embodiment of signal timing related to the pixel shown in FIG. 2.
  • FIG. 5 is a schematic diagram of still another embodiment of the signal timing involved in the pixel shown in FIG. 2.
  • FIG. 6 is a schematic diagram of still another embodiment of the signal timing involved in the pixel shown in FIG. 2.
  • first and second features are in direct contact with each other; and may also include
  • additional components are formed between the above-mentioned first and second features, so that the first and second features may not be in direct contact.
  • present disclosure may reuse component symbols and/or labels in multiple embodiments. Such repeated use is based on the purpose of brevity and clarity, and does not in itself represent the relationship between the different embodiments and/or configurations discussed.
  • spatially relative terms here such as “below”, “below”, “below”, “above”, “above” and similar, may be used to facilitate the description of the drawing in the figure The relationship between one component or feature relative to another component or feature is shown.
  • the original meaning of these spatially-relative vocabulary covers not only the orientation shown in the figure, but also the various orientations in which the device is in use or operation.
  • the device may be placed in other orientations (for example, rotated 90 degrees or in other orientations), and these spatially-relative description vocabulary should be explained accordingly.
  • the time-of-flight ranging solution disclosed in this application can send pulses intermittently from the pulse generating unit, and continuously perform multiple signal samplings during the time-of-flight sensor to obtain the corresponding reflected signal (the single target is reflected by the target). Pulse-based sampling results, so as to realize the pulse modulation-based analog continuous wave modulation (continuous wave modulation) sensing mechanism.
  • the first solution of the present application is to adjust the sampling interval of the time-of-flight sensor
  • the second solution of the present application is to adjust the pulse type, and its purpose is to improve the performance of high dynamic range sampling, which is further described as follows.
  • Fig. 1 is a functional block diagram of an embodiment of a distance measurement system based on flight time according to the present application.
  • the ranging system 100 can be used to detect the distance between the target 102 and the ranging system 100. It should be noted that the distance between the target 102 and the ranging system 100 should be less than or equal to the maximum measurement distance of the ranging system 100.
  • the ranging system 100 may be a three-dimensional imaging system, which may use a time-of-flight method to measure the distance of surrounding objects, thereby obtaining depth of field and three-dimensional image information.
  • the ranging system 100 can be implemented as a variety of different types of time-of-flight ranging systems, such as a time-of-flight-based optical ranging system, a time-of-flight-based acoustic ranging system, and a time-of-flight-based radar ranging system. , Or other types of time-of-flight ranging systems.
  • time-of-flight ranging solution of the present application by taking the example of the ranging system 100 implemented as an optical ranging system.
  • the time-of-flight ranging solution of the present application can be applied to any time-of-flight ranging system.
  • the ranging system 100 may include (but is not limited to) a pulse generating unit 110, a control circuit 120, and a time-of-flight sensor 130.
  • the pulse generating unit 110 is used to send pulses intermittently, and has a pulse length T. After sending a pulse, the pulse generating unit 110 will stop sending the pulse for a period of time, and this period of time can be much longer or longer than the pulse length T. Until the next startup, the pulse generating unit 110 can send a pulse again.
  • the ranging system 100 may be an optical ranging system based on time of flight. Therefore, the pulse generating unit 110 may be implemented by a light pulse generating unit to generate a pulsed light signal EL.
  • the pulsed light signal EL may be a single light pulse that is generated intermittently. That is, the light pulse generating unit may intermittently send a single light pulse as a single pulse generated by the pulse generating unit 110 intermittently.
  • the pulse generating unit 110 may include (but is not limited to) a driving circuit and a light emitting unit (not shown in FIG. 1). The driving circuit is used to drive the light-emitting unit so that the light-emitting unit emits a single light pulse intermittently.
  • the light-emitting unit may be (but is not limited to) a semiconductor laser (also known as a laser diode (LD)), a light emitting diode (LED) or other light-emitting unit that can generate light pulses.
  • a semiconductor laser also known as a laser diode (LD)
  • LED light emitting diode
  • the semiconductor laser The generated light pulse is coherent light, and the light pulse generated by the light emitting diode is incoherent light.
  • the pulse generating unit 110 may generate other types of pulses, such as acoustic wave pulses or electromagnetic wave pulses.
  • the pulse generating unit 110 may be implemented by an acoustic wave pulse generator.
  • the sonic pulse generator is used to intermittently send a single sonic pulse (such as an ultrasonic pulse) as a single pulse generated by the pulse generating unit 110 intermittently.
  • the pulse generating unit 110 may be implemented by an electromagnetic wave pulse generator.
  • the electromagnetic wave pulse generator is used to intermittently send a single electromagnetic wave pulse as a single pulse generated by the pulse generating unit 110 intermittently.
  • the control circuit 120 is coupled to the pulse generating unit 110 for controlling the pulse generating unit 110 to generate a pulsed light signal EL.
  • the control circuit 120 may control the pulse generating unit 110 to send a single light pulse intermittently.
  • the control circuit 120 may control the driving circuit included in the pulse generating unit 110 so that the light emitting unit included in the driving circuit driving the pulse generating unit 110 sends a single light pulse intermittently.
  • the time-of-flight sensor 130 is controlled by the control circuit 120 to sample a reflected signal RL to detect the distance between the ranging system 100 (or the time-of-flight sensor 130) and the target 102, wherein the reflected signal RL is pulsed light
  • the signal EL is generated by being reflected by the target 102.
  • the control circuit 120 may be the main control unit in the terminal device and need not be included in the ranging system 100.
  • the time-of-flight sensor 130 continuously executes the signal multiple times according to a sampling time interval within the adjustable predetermined time TR (for the convenience of explanation, it is represented by the waveform marked with the time length as TR). Sampling is used to generate a sampling result of the reflection signal RL. In other words, the reflection signal RL that reaches the time-of-flight sensor 130 within the predetermined time TR can be sensed.
  • the predetermined time TR is set to be greater than or equal to the pulse length T, for example, greater than or equal to The pulse length T is several times, so that the reflected signal RL from near and far can be captured, but the disadvantage is that the amount of information received from near is often far more than the amount of information from far, resulting in far The amount of information is easily affected by the background light, causing shot noise. Therefore, the predetermined time TR in this application is adjustable, and the details are described later.
  • the time-of-flight sensor 130 may calculate the phase shift between the reflected signal RL and the pulsed light signal EL sent by the pulse generating unit 110 according to the sampling result .
  • the time-of-flight sensor 130 may include (but is not limited to) a pixel array 132 and a processing circuit 134.
  • the pixel array 132 includes a plurality of pixels (not shown in FIG. 1), and each pixel may include a light sensor (not shown in FIG. 1) to generate a photo response signal in response to the reflected signal RL.
  • the control circuit 120 can enable the photosensor of each pixel to selectively output the corresponding light response signal of each pixel to the processing circuit 134.
  • the processing circuit 134 can sample the output of each pixel (such as the photoresponse signal of each pixel) at intervals of the sampling time interval in the predetermined time TR according to a sampling control signal SC (which can be generated by the control circuit 120), Based on this, a sampling result SR is generated. Next, the processing circuit 134 may perform signal processing on the sampling result SR, such as mixing processing and discrete Fourier transform, to calculate the reflected signal RL received by each pixel and the pulse sent by the pulse generating unit 110
  • the phase shift between the light signals EL is used to detect the flight time of the pulsed light signal EL, and calculate the distance between the target 102 and the reference position based on the flight time.
  • the reference position may be (but is not limited to) the position of the ranging system 100.
  • Fig. 2 is a schematic diagram of an embodiment of the circuit structure of a single pixel in the pixel array 132 shown in Fig. 1. Please refer to Figure 2 together with Figure 1.
  • the pixel 332 includes (but is not limited to) a photosensor PD, a first readout circuit (such as a photoelectric readout circuit) 333, and a second readout circuit (such as a photoelectric readout circuit) 334.
  • the light sensor PD (such as a photodiode) is used for light sensing operation.
  • the photosensor PD can sense the reflected signal RL to correspondingly generate a photo response signal PR, where the photo response signal PR can be output by at least one of the first readout circuit 333 and the second readout circuit 334.
  • the photosensor PD can convert the received light signal into a photocurrent signal of a corresponding size, that is, the photoresponse signal PR can be a current signal that characterizes the magnitude of the light signal, and the first readout circuit 333/second readout The output circuit 334 is used to read the photocurrent signal.
  • the first readout circuit 333 can selectively transmit the light response signal PR generated by the photosensor PD according to a first control signal TX1 to generate a first pixel output PO1, wherein the first control signal TX1 can be provided by the control circuit 120 .
  • the pixel 332 can selectively transmit the light response signal PR to the processing circuit 130 through the first readout circuit according to the first control signal TX1 to generate the first pixel output PO1 and output it to the processing circuit 130.
  • the second readout circuit 334 can selectively transmit the light response signal PR generated by the photosensor PD according to a second control signal TX2 to generate a second pixel output PO2, wherein the second control signal TX2 can be provided by the control circuit 120 , And have a different phase from the first control signal TX1.
  • the pixel 332 can selectively transmit the photoresponse signal PR to the processing circuit 130 through the second readout circuit according to the second control signal TX2 to generate a second pixel output PO2 and output it to the processing circuit 130.
  • the first control signal TX1 and the second control signal TX2 can be provided by the control circuit 120 shown in FIG. 1.
  • the first readout circuit 333 may include (but is not limited to) a first reset transistor MR1, a first transfer transistor MT1, a first output transistor MF1, and a first read transistor MW1.
  • the second readout circuit 334 includes (but is not limited to) a second reset transistor MR2, a second transfer transistor MT2, a second output transistor MF2, and a second read transistor MW2.
  • the first reset transistor MR1 and the second reset transistor MR2 both reset a first floating diffusion node FD1 and a second floating diffusion node FD2 according to a reset signal RST, wherein the reset signal RST can be provided by the control circuit 120.
  • the first transfer transistor MT1 and the second transfer transistor MT2 are both coupled to the photosensor PD, and are turned on according to the first control signal TX1 and the second control signal TX2 respectively, that is, the first transfer transistor MT1 and the second transfer transistor MT2 are respectively subjected to It is controlled by the first control signal TX1 and the second control signal TX2 to realize the connection and disconnection with the photosensor PD.
  • the first output transistor MF1 and the first output transistor MF2 are respectively used to amplify the voltage signals of the first floating diffusion node FD1 and the second floating diffusion node FD2 to generate a first pixel output PO1 and a second pixel output PO2, respectively.
  • the first reading transistor MW1 and the second reading transistor MW2 both selectively output the first pixel output PO1 and the second pixel output PO2 according to a selection signal SEL, wherein the selection signal SEL can be provided by the control circuit 120.
  • FIG. 3 is a schematic diagram of an embodiment of signal timing related to the pixel 332 shown in FIG. 2.
  • the pulse generating unit 110 sends a total of two pulses PE.
  • the sensor 130 will sample twice. The two sampling methods are roughly the same, but the time points are different, so that the previous sample can be used for the reflected signal RL.
  • the part that is reflected to the sensor 130 faster is sampled, and the latter sampling can be performed for the part of the reflected signal RL that is reflected to the sensor 130 slowly.
  • the first pulse PE after the first pulse PE is emitted at time t1, it is reflected to become the reflected signal RL, because the reflected signal RL carries the energy reflected back from different depths by the first pulse PE , The energy reflected from near will reach the pixel 332 faster than the energy reflected from far away. That is to say, in theory, any time after the time point t1 may have the energy of the reflected signal RL of the first pulse PE (please refer to the indication of the reflected signal RL after the time point t1 in FIG. 3).
  • the length of the predetermined time TR for each sampling can be increased, so that the amount of information sampled corresponds to a wider depth range. However, the information reflected from the distance will be far away from the sampled information. Is less than the information reflected from near, which makes the information reflected from far away susceptible to noise interference.
  • different target depth samples are performed for different pulse PEs.
  • the control circuit 120 causes the sensor 130 to sample the first signal within the time range of the predetermined time TR1; for the second pulse PE in FIG. 3, the control circuit 120 causes the sensor 130 to The second signal sampling is performed within the time range of the predetermined time TR2.
  • the predetermined time TR1 is later than the emission time of the first pulse PE by the first time difference tX
  • the predetermined time TR2 is later than the emission time of the second pulse PE by the first time difference tX+2TN
  • the predetermined time TR1 and the predetermined time TR2 The length is the same.
  • the first signal sampling can sample the energy of the first pulse PE reflected back to the sensor 130 in the predetermined time TR1; the second signal sampling can sample the second pulse in the predetermined time TR2
  • the PE reflects the energy back to the sensor 130 from a far distance, and the target sampling depths of the two are different and do not repeat.
  • multiple pulses PE are emitted (for example, thousands of times), and the first signal sampling or the second signal sampling is performed according to a predetermined time TR1 or a predetermined time TR2, for example, according to a predetermined ratio
  • the pulse PE allocated multiple times corresponds to the first signal sample or the second signal sample respectively, wherein the number of pulse PE allocated corresponding to the first signal sample is less than the number of pulse PE allocated corresponding to the second signal sample
  • the number of pulse PEs is used to balance the energy from near and far, so that the energy from the near will not be overexposed, and to increase the energy from the far. For example, 80% of the pulse PE corresponds to the second signal sample to sample the remote information; the remaining 20% of the pulse PE corresponds to the first signal sample to sample the incoming information.
  • the predetermined ratio can be adjusted according to the required dynamic range.
  • the first time difference tX in FIG. 3 can be set to, for example, half of the pulse length T, but the application is not limited thereto.
  • the difference between the first time difference and the second time difference can also be greater or less than the two sampling intervals TN, but should not be less than the sampling interval TN.
  • the predetermined time TR1 may include two sampling intervals TN (that is, time point t2 to time point t4 and time point t4 to time point t6); the predetermined time TR2 may include two sampling intervals TN (that is, time point t10 to time point t12 and time point From point t12 to time point t14), the time length of each sampling interval TN is equal to the pulse length T.
  • the first control signal TX1 has the same waveform in each sampling interval TN; the second control signal TX2 has the same waveform in each sampling interval TN. There may be a 180 degree phase difference between the second control signal TX2 and the first control signal TX1.
  • the length of the predetermined time can be adjusted according to the required dynamic range, for example, the predetermined time TR1 is changed to the predetermined time TR3, and the predetermined time TR3 can be used for the third signal sampling.
  • the predetermined time TR3 may include 4 sampling intervals TN, for example, the predetermined time TR3 starts from the time point t2 and lasts for 4 sampling intervals TN, so the predetermined time TR3 may include both the predetermined time TR1 and the predetermined time TR2.
  • Dynamic Range Therefore, multiple pulse PEs can be allocated to correspond to different types of signal samples arbitrarily according to the requirements of the dynamic range. For example, in some embodiments, 15% of the pulse PE can be allocated to the third according to the predetermined ratio. Signal sampling, 85% of the pulse PE corresponds to the second signal sample; or 10% of the pulse PE corresponds to the first signal sample, 10% of the pulse PE corresponds to the third signal sample, and 80% of the pulse PE corresponds to the second signal sample The second signal is sampled.
  • each pixel is sampled once every sampling time interval in each sampling interval TN, where the sampling time interval may be a quarter of the pulse length T.
  • the sampling time interval may also be one-eighth or one-sixteenth of the pulse length T.
  • the pulse generating unit 110 will intermittently send multiple pulses PE with a phase of 0 degrees, then intermittently send multiple pulses PE with a phase of 90 degrees, and then intermittently send multiple pulses of phase PE. 180-degree pulse PE, and then intermittently send multiple 270-degree pulse PE.
  • the first control signal TX1 and the second control signal TX2 can be adjusted for pulses PE of different phases. For example, for the pulse PE with phases of 0 degrees and 90 degrees, the first control signal TX1 and the second control signal TX2 of the same waveform can be used; for the pulse PE with phases of 180 degrees and 270 degrees, the first control signal TX1 and the second control signal TX2 can be used.
  • the control signal TX1 and the second control signal TX2 are swapped and moved back by tX, as shown in FIG. 5, so that the start time point t6 of the predetermined time TR corresponding to the 180-degree pulse PE and the transmission of the 180-degree pulse PE
  • the time point t5 still has the first time difference tX. If this adjustment is not performed, the start time point of the predetermined time TR corresponding to the pulse PE with a phase of 180 degrees will be at t5, so that the predetermined time TR needs to be extended by tX to maintain the dynamic range.
  • the second solution of the present application is roughly the same as the first solution above, except that in the second solution, the predetermined time TR4 of the time-of-flight sensor 130 is a fixed length, for example, the predetermined time TR4 is four times the length of the sampling interval TN , But not limited to this.
  • the control circuit 120 controls the pulse generating unit 110 to send pulse groups intermittently to replace the single pulse in the first solution.
  • the pulse group includes a first pulse PE1 and a second pulse PE2.
  • the pulse length of the first pulse PE1 and the pulse length of the second pulse PE2 are the same, and both are T.
  • the transmission time of the second pulse PE2 is at least the pulse length T behind the first pulse PE1 in the same pulse group. In other words, the transmission time of the second pulse PE2 can be more than 2 pulse lengths T behind the first pulse PE1 in the same pulse group.
  • the intensity of the first pulse PE1 is different from the intensity of the second pulse PE2.
  • the intensity of the first pulse PE1 is deliberately made higher than the intensity of the second pulse PE2, and the start time point of the predetermined time TR4 is at least backward It is extended to the sending time point of the second pulse PE2. Roughly speaking, the energy reflected back to the time-of-flight sensor 130 in the first pulse PE1 before the start of the predetermined time TR4 is too late to be sampled.
  • the time-of-flight sensor 130 will only receive the first pulse PE1 which is reflected back slowly. The energy of the time-of-flight sensor 130 (i.e.
  • the time-of-flight sensor 130 will only receive the energy reflected back to the time-of-flight sensor 130 (i.e. near information) in the second pulse PE2. ). Since the intensity of the first pulse PE1 is relatively high, the far information energy of the first pulse PE1 can be increased to balance the energy of the near information of the second pulse PE2. Therefore, by designing the intensities of the first pulse PE1 and the second pulse PE2 to have different magnitudes, the energy of the far information and the near information received in the predetermined time TR4 can be controlled to be approximately the same.

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  • Computer Networks & Wireless Communication (AREA)
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  • Optical Radar Systems And Details Thereof (AREA)

Abstract

一种基于飞行时间的测距方法和基于飞行时间的测距系统。包括：从脉冲产生单元(110)间歇性地发送多个第一脉冲(PE)，其中多个第一脉冲(PE)被目标物反射而产生多个第一反射信号(RL)；使飞行时间传感器对多个第一反射信号(RL)分别选择性地执行第一信号采样或第二信号采样以产生第一采样结果，其中第一信号采样的开始时间点(t2)和对应的第一脉冲的发送时间点(t1)具有第一时间差(tX)，且第一信号采样持续第一预定时间(TR1)，以及第二信号采样的开始时间点(t10)和对应的第一脉冲的发送时间点(t7)具有第二时间差(tX+2TN)，且第二信号采样持续第二预定时间(TR2)，且第一时间差小于第二时间差。

Description

基于飞行时间的测距方法和相关测距系统 技术领域
本申请涉及测距和深度传感技术，尤其涉及一种基于飞行时间的测距方法，及其相关的测距系统。
背景技术
基于飞行时间(time of flight，TOF)的距离测量技术中，脉冲调制(pulse modulation)通过光脉冲发送和接收的时间差来测量目标物的距离，具备了较简单的测量机制。脉冲调制对时间测量精度要求较高。然而，在高动态范围(high dynamic range,HDR)的应用中，现有的技术对于距离测量所能覆盖的范围，以及远处信息受背景光的影响程度的调控，仍有相当大的改善空间。
发明内容
本申请的一实施例公开了一种基于飞行时间的测距方法，包括：从脉冲产生单元间歇性地发送多个第一脉冲，其中所述多个第一脉冲被目标物反射而产生多个第一反射信号；使飞行时间传感器对所述多个第一反射信号分别选择性地执行第一信号采样或第二信号采样以产生第一采样结果，其中所述第一信号采样的开始时间点和对应的所述第一脉冲的发送时间点具有第一时间差，且所述第一信号采样持续第一预定时间，以及所述第二信号采样的开始时间点和对应的所述第一脉冲的发送时间点具有第二时间差，且所述第二信号采样持续第二预定时间，且所述第一时间差小于所述第二时间差；根据所述第一采样结果，检测所述多个第一脉冲从所述脉冲产生单元到所述飞行时间传感器的飞行时间；以及根据所述飞行时间判断 所述目标物与参考位置之间的距离。
本申请的另一实施例公开了一种基于飞行时间的测距系统，包括：脉冲产生单元；控制电路，耦接于所述脉冲产生单元，用以控制所述脉冲产生单元间歇性地发送多个第一脉冲，其中所述多个第一脉冲被目标物反射而产生多个第一反射信号；以及飞行时间传感器，由所述控制电路所控制，用以对所述多个第一反射信号分别选择性地执行第一信号采样或第二信号采样以产生第一采样结果，其中所述第一信号采样的开始时间点和对应的所述第一脉冲的发送时间点具有第一时间差，且所述第一信号采样持续第一预定时间，以及所述第二信号采样的开始时间点和对应的所述第一脉冲的发送时间点具有第二时间差，且所述第一时间差小于所述第二时间差，且所述第二信号采样持续第二预定时间，并根据所述第一采样结果，检测所述多个第一脉冲从所述脉冲产生单元到所述飞行时间传感器的飞行时间，以及根据所述飞行时间判断所述目标物与参考位置之间的距离。
本申请的又另一实施例公开了一种基于飞行时间的测距方法，包括：从脉冲产生单元间歇性地发送多个脉冲组，其中各脉冲组包括第一脉冲和第二脉冲，所述第一脉冲的强度和所述第二脉冲的强度不同，且所述多个脉冲组被目标物反射而产生多个反射信号组；使飞行时间传感器对所述多个反射信号组分别执行信号采样以产生采样结果，其中所述信号采样持续预定时间；根据所述采样结果，检测所述多个脉冲组从所述脉冲产生单元到所述飞行时间传感器的飞行时间；以及根据所述飞行时间测量所述目标物与参考位置之间的距离。
本申请的又另一实施例公开了一种基于飞行时间的测距系统，包括：脉冲产生单元；控制电路，耦接于所述脉冲产生单元，用以控制所述脉冲产生单元间歇性地发送多个脉冲组，其中各脉冲组包括第一脉冲和第二脉冲，所述第一脉冲的强度和所述第二脉冲的强度不同，且所述多个脉冲组被目标物反射而产生多个反射信号组； 以及飞行时间传感器，由所述控制电路所控制，用以对所述多个反射信号组分别执行信号采样以产生采样结果，其中所述信号采样持续预定时间；所述飞行时间传感器还根据所述采样结果检测所述多个脉冲组从所述脉冲产生单元到所述飞行时间传感器的飞行时间，以及根据所述飞行时间测量所述目标物与所述测距系统之间的距离。
本申请所公开的基于飞行时间的测距方法及相关测距系统可以通过对采样区间或脉冲型态的调控，来提升高动态范围采样的效能。
附图说明
图1是本申请基于飞行时间的测距系统的一实施例的功能方框示意图。
图2是图1所示的测距系统的像素阵列中单个像素的电路结构的一实施例的示意图。
图3是图2所示的像素所涉及的信号时序的一实施例的示意图。
图4是图2所示的像素所涉及的信号时序的另一实施例的示意图。
图5是图2所示的像素所涉及的信号时序的又另一实施例的示意图。
图6是图2所示的像素所涉及的信号时序的又另一实施例的示意图。
具体实施方式
以下揭示内容提供了多种实施方式或例示，其能用以实现本揭示内容的不同特征。下文所述之组件与配置的具体例子系用以简化本揭示内容。当可想见，这些叙述仅为例示，其本意并非用于限制本揭示内容。举例来说，在下文的描述中，将一第一特征形成于一第二特征上或之上，可能包括某些实施例其中所述的第一与第二特征彼此直接接触；且也可能包括某些实施例其中还有额外的组件形 成于上述第一与第二特征之间，而使得第一与第二特征可能没有直接接触。此外，本揭示内容可能会在多个实施例中重复使用组件符号和/或标号。此种重复使用乃是基于简洁与清楚的目的，且其本身不代表所讨论的不同实施例和/或组态之间的关系。
再者，在此处使用空间上相对的词汇，譬如「之下」、「下方」、「低于」、「之上」、「上方」及与其相似者，可能是为了方便说明图中所绘示的一组件或特征相对于另一或多个组件或特征之间的关系。这些空间上相对的词汇其本意除了图中所绘示的方位之外，还涵盖了装置在使用或操作中所处的多种不同方位。可能将所述设备放置于其他方位(如，旋转90度或处于其他方位)，而这些空间上相对的描述词汇就应该做相应的解释。
虽然用以界定本申请较广范围的数值范围与参数皆是约略的数值，此处已尽可能精确地呈现具体实施例中的相关数值。然而，任何数值本质上不可避免地含有因个别测试方法所致的标准偏差。在此处，「相同」通常系指实际数值在一特定数值或范围的正负10％、5％、1％或0.5％之内。或者是，「相同」一词代表实际数值落在平均值的可接受标准误差之内，视本申请所属技术领域中具有通常知识者的考虑而定。当可理解，除了实验例之外，或除非另有明确的说明，此处所用的所有范围、数量、数值与百分比(例如用以描述材料用量、时间长短、温度、操作条件、数量比例及其他相似者)均经过「相同」的修饰。因此，除非另有相反的说明，本说明书与附随申请专利范围所揭示的数值参数皆为约略的数值，且可视需求而更动。至少应将这些数值参数理解为所指出的有效位数与套用一般进位法所得到的数值。在此处，将数值范围表示成由一端点至另一端点或介于二端点之间；除非另有说明，此处所述的数值范围皆包括端点。
本申请所公开的飞行时间测距方案可通过从脉冲产生单元间歇性地发送脉冲，并且在飞行时间传感器持续执行多次的信号采样，以得到相对应的反射信号(由目标物反射所述单个脉冲而产生)的 采样结果，从而实现基于脉冲调制的模拟连续波调制(continuous wave modulation)的传感机制。本申请的第一种方案为调整飞行时间传感器的采样区间，本申请的第二种方案为调整脉冲的型态，其目的皆为了提升高动态范围采样的效能，进一步的说明如下。
图1是本申请基于飞行时间的测距系统的一实施例的功能方框示意图。测距系统100可用于探测目标物102与测距系统100之间的距离，需注意的是，目标物102与测距系统100之间的距离应小于或等于测距系统100的最大测量距离。举例来说(但本申请不限于此)，测距系统100可以是三维成像系统，其可采用时间飞行法来测量周遭目标物的距离，从而获得景深和三维图像信息。
值得注意的是，测距系统100可实施为多种不同类型的飞行时间测距系统，诸如基于飞行时间的光学测距系统、基于飞行时间的声波测距系统、基于飞行时间的雷达测距系统，或其他类型的飞行时间测距系统。为简洁起见，以下以测距系统100实施为光学测距系统的实施例来说明本申请的飞行时间测距方案。然而，本领域所属技术人员应可了解本申请的飞行时间测距方案可应用于任何基于飞行时间的测距系统。
测距系统100可包括(但不限于)一脉冲产生单元110、一控制电路120和一飞行时间传感器130。脉冲产生单元110用以间歇性地发送脉冲，其具有一脉冲长度T。在发送出一个脉冲之后，脉冲产生单元110会停止发送脉冲一段时间，而这段时间可远大于或大于脉冲长度T。一直到下一次启动时，脉冲产生单元110可再次发送一个脉冲。
于本申请中，测距系统100可以是基于飞行时间的光学测距系统，因此，脉冲产生单元110可由一光脉冲产生单元来实施，以产生一脉冲光信号EL。在本申请的第一种方案中，脉冲光信号EL可以是间歇产生的单个光脉冲。也就是说，所述光脉冲产生单元可间歇性地发送单个光脉冲，作为脉冲产生单元110间歇产生的单个脉冲。举例来说，脉冲产生单元110可包括(但不限于)一驱动电路 和一发光单元(图1未示)。所述驱动电路用以驱动所述发光单元，使所述发光单元间歇性地发出单个光脉冲。所述发光单元可以是(但不限于)半导体激光器(又可称作激光二极管(laser diode，LD))、发光二极管(light emitting diode，LED)或其他可以产生光脉冲的发光单元，其半导体激光器所产生的光脉冲是相干光(coherent light)，而发光二极管所产生的光脉冲是非相干光(incoherent light)。
值得注意的是，脉冲产生单元110可产生其他类型的脉冲，诸如声波脉冲或电磁波脉冲。例如，在测距系统100实施为声波测距系统的实施例中，脉冲产生单元110可由一声波脉冲产生器来实施。所述声波脉冲产生器用以间歇性地发送单个声波脉冲(诸如超声波脉冲)，作为脉冲产生单元110间歇产生的单个脉冲。又例如，在测距系统100实施为雷达测距系统的实施例中，脉冲产生单元110可由一电磁波脉冲产生器来实施。所述电磁波脉冲产生器用以间歇性地发送单个电磁波脉冲，作为脉冲产生单元110间歇产生的单个脉冲。
控制电路120耦接于脉冲产生单元110，用以控制脉冲产生单元110产生脉冲光信号EL。例如，控制电路120可控制脉冲产生单元110间歇性地发送单个光脉冲。又例如，控制电路120可控制脉冲产生单元110所包括的驱动电路，使所述驱动电路驱动脉冲产生单元110所包括的发光单元间歇性地发送单个光脉冲。飞行时间传感器130由控制电路120所控制，用以对一反射信号RL进行采样，以检测测距系统100(或飞行时间传感器130)与目标物102之间的距离，其中反射信号RL是脉冲光信号EL被目标物102反射而产生。在另外的实施例中，控制电路120可以是终端设备中的主控单元而不必包含在测距系统100之中。
于本申请的第一种方案中，飞行时间传感器130在可调控的预定时间TR(为方便说明，以时间长度标记为TR的波形来表示)内持续地根据一采样时间间隔执行多次的信号采样，以产生反射信号 RL的采样结果，换句话说，在预定时间TR的范围内抵达飞行时间传感器130的反射信号RL均可被感测到。一般来说，由于从近处和远处反射回来的反射信号RL会具有不同的到达时间，因此一般为了提升动态范围，会将预定时间TR设定为大于或等于脉冲长度T，例如大于或等于脉冲长度T的若干倍，使来自近处和远处的反射信号RL都能被捕获，但缺点是所收到的来自近处的信息量往往远多于来自远处的信息量，造成远处的信息量容易受到背景光的影响，引发散粒噪声(shot noise)。因此，本申请中的预定时间TR为可调控的，其细节说明于后。
在执行多次的所述信号采样以产生所述采样结果之后，飞行时间传感器130可根据所述采样结果计算出反射信号RL与脉冲产生单元110所发送的脉冲光信号EL之间的相位偏移。举例来说，飞行时间传感器130可包括(但不限于)一像素阵列132和一处理电路134。像素阵列132包括多个像素(图1未示)，各像素可包括一光传感器(图1未示)以回应反射信号RL产生一光响应信号(photo response signal)。控制电路120可使各像素的光传感器选择性地将各像素相应的光响应信号输出到处理电路134。
处理电路134可根据一采样控制信号SC(其可由控制电路120所产生)，于预定时间TR中每隔所述采样时间间隔对各像素的输出(诸如各像素的光响应信号)进行一次采样，并据以产生一采样结果SR。接下来，处理电路134可对采样结果SR进行信号处理，这些信号处理可以是诸如混频处理和离散傅里叶变换，以计算各像素所接收的反射信号RL与脉冲产生单元110所发送的脉冲光信号EL之间的相位偏移，从而检测出脉冲光信号EL的飞行时间，以及根据飞行时间计算出目标物102与参考位置的距離。所述参考位置可以是(但不限于)测距系统100的位置。
为了方便说明，以下采用一种像素电路的实施方式来说明本申请所公开的飞行时间测距方案。然而，本发明并不以此为限。图2是图1所示的像素阵列132中单个像素的电路结构的一实施例的示 意图。请连同图1参阅图2。于此实施例中，像素332包括(但不限于)一光传感器PD、一第一读出电路(诸如光电读出电路)333和一第二读出电路(诸如光电读出电路)334。光传感器PD(诸如光电二极管)用以进行光传感操作。例如，光传感器PD可传感反射信号RL以对应地产生一光响应信号PR，其中光响应信号PR可通过第一读出电路333和第二读出电路334其中的至少一个读出电路输出。在一些实施例中，光传感器PD可将接收到的光信号转换成对应大小的光电流信号，即光响应信号PR可以是表征光信号大小的电流信号，第一读出电路333/第二读出电路334用于读出所述光电流信号。
第一读出电路333可根据一第一控制信号TX1选择性地传输光传感器PD所产生的光响应信号PR，以产生一第一像素输出PO1，其中第一控制信号TX1可由控制电路120来提供。也就是说，像素332可根据第一控制信号TX1选择性地将光响应信号PR通过所述第一读出电路传送到处理电路130，以产生第一像素输出PO1并输出至处理电路130。第二读出电路334可根据一第二控制信号TX2选择性地传输光传感器PD所产生的光响应信号PR，以产生一第二像素输出PO2，其中第二控制信号TX2可由控制电路120来提供，并具有与第一控制信号TX1不同的相位。像素332可根据第二控制信号TX2选择性地将光响应信号PR通过所述第二读出电路传送到处理电路130，以产生第二像素输出PO2并输出至处理电路130。在此实施例中，第一控制信号TX1和第二控制信号TX2可由图1所示的控制电路120来提供。
于此实施例中，第一读出电路333可包括(但不限于)一第一复位晶体管MR1、一第一传输晶体管MT1、一第一输出晶体管MF1和一第一读取晶体管MW1。第二读出电路334包括(但不限于)一第二复位晶体管MR2、一第二传输晶体管MT2、一第二输出晶体管MF2和一第二读取晶体管MW2。第一复位晶体管MR1和第二复位晶体管MR2均根据一复位信号RST来分别复位一第一浮动扩散节点FD1和一第二浮动扩散节点FD2，其中复位信号RST可由控制电路120 来提供。第一传输晶体管MT1和第二传输晶体管MT2均耦接于光传感器PD，分别根据第一控制信号TX1和第二控制信号TX2来导通，即第一传输晶体管MT1和第二传输晶体管MT2分别受控于第一控制信号TX1和第二控制信号TX2，以实现与光传感器PD的连接与断开。第一输出晶体管MF1和第一输出晶体管MF2分别用以放大第一浮动扩散节点FD1和第二浮动扩散节点FD2的电压信号，以分别产生一第一像素输出PO1和一第二像素输出PO2。第一读取晶体管MW1和第二读取晶体管MW2均根据一选择信号SEL，分别将第一像素输出PO1和第二像素输出PO2选择性地输出，其中选择信号SEL可由控制电路120来提供。
请一并参阅图1、图2和图3。图3是图2所示的像素332所涉及的信号时序的一实施例的示意图。图3中，脉冲产生单元110共发送两次脉冲PE，对应地，传感器130会进行两次的采样，两次采样的方式大致相同，但时间点不同，使前一次采样可针对反射信号RL中较快反射至传感器130的部分进行采样，后一次采样可针对反射信号RL中较慢反射至传感器130的部分进行采样。
进一步来说，以第一个脉冲PE来说，第一个脉冲PE于时间点t1发出后，经过反射成为反射信号RL，由于反射信号RL带有第一个脉冲PE从不同深度反射回来的能量，从近处反射回来的能量会较从远处反射回来的能量更快抵达像素332。也就是说，理论上从时间点t1之后任何时间都有可能带有第一个脉冲PE的反射信号RL的能量(请参考图3中反射信号RL在时间点t1之后的标示)。一般在高动态范围的应用中，可以增加每次采样的预定时间TR的长度，使采样到的信息量对应更广的深度范围，但采样到的信息中，反射自远处的信息会远远的少于反射自近处的信息，造成反射自远处的信息容易受到噪声干扰。
本实施例中，针对不同的脉冲PE进行不同的目标深度采样。例如针对图3中的第一个脉冲PE，控制电路120使传感器130对在预定时间TR1的时间范围内进行第一信号采样；对图3中的第二个脉 冲PE，控制电路120使传感器130对在预定时间TR2的时间范围内进行第二信号采样。其中预定时间TR1相对于第一个脉冲PE的发出时间晚了第一时间差tX，预定时间TR2相对于第二个脉冲PE的发出时间晚了第一时间差tX+2TN，预定时间TR1和预定时间TR2的长度相同。因此，所述第一信号采样可以在预定时间TR1中采样到第一个脉冲PE从较近处反射回传感器130的能量；所述第二信号采样可以在预定时间TR2中采样到第二个脉冲PE从较远处反射回传感器130的能量，两者的目标采样深度不同且不重复。
在本实施例中，会发射多次的脉冲PE(例如上千次)，并依据预定时间TR1或预定时间TR2来进行所述第一信号采样或所述第二信号采样，例如可以依据预定比例来分配多次的脉冲PE分别对应所述第一信号采样或所述第二信号采样，其中被分配对应所述第一信号采样的脉冲PE的数目少于被分配对应所述第二信号采样的脉冲PE的数目，以平衡来自近处和远处的能量，使来自近处的能量不会过度曝光，并拉高来自远处的能量。举例来说，80％的脉冲PE对应所述第二信号采样来针对远处信息进行采样；剩下20％的脉冲PE对应所述第一信号采样来针对进处信息进行采样。所述预定比例可以依据所需要的动态范围进行调整。
图3中第一时间差tX可设定为例如脉冲长度T的一半，但本申请不以此限。所述第一时间差和所述第二时间差的差也可以大于或小于两个采样区间TN，但应不小于采样区间TN。预定时间TR1可以包含两个采样区间TN(即时间点t2至时间点t4和时间点t4至时间点t6)；预定时间TR2可以包含两个采样区间TN(即时间点t10至时间点t12和时间点t12至时间点t14)，其中各采样区间TN的时间长度等于脉冲长度T。第一控制信号TX1于各采样区间TN的波形相同；第二控制信号TX2于各采样区间TN的波形相同。第二控制信号TX2和第一控制信号TX1之间可具有180度的相位差。在某些实施例中，可以依据所需要的动态范围调整预定时间的长度，例如将预定时间TR1改为预定时间TR3，预定时间TR3可用于第三信号采样。
请参考图4，预定时间TR3可以包含4个采样区间TN，例如预定时间TR3从时间点t2开始持续4个采样区间TN，因此预定时间TR3便可以同时包括预定时间TR1和预定时间TR2所针对的动态范围。因此，可以任意地依动态范围的需求来分配多次的脉冲PE去对应不同类型的信号采样，例如在某些实施例中可以依据所述预定比例来分配15％的脉冲PE对应所述第三信号采样，85％的脉冲PE对应所述第二信号采样；或分配10％的脉冲PE对应所述第一信号采样，10％的脉冲PE对应所述第三信号采样，80％的脉冲PE对应所述第二信号采样。
另外，于各采样区间TN中每隔所述采样时间间隔对各像素的输出进行一次采样，其中所述采样时间间隔可以是脉冲长度T的四分之一。然而，本申请并不以此为限，所述采样时间间隔也可以是脉冲长度T的八分之一或十六分之一。
在本申请中，脉冲产生单元110会间歇性地发送多个相位为0度的脉冲PE，之后再间歇性地发送多个相位为90度的脉冲PE，之后再间歇性地发送多个相位为180度的脉冲PE，之后再间歇性地发送多个相位为270度的脉冲PE。在某些实施例中，可以针对不同相位的脉冲PE调整第一控制信号TX1和第二控制信号TX2。举例来说，对于相位为0度和90度的脉冲PE，可以使用相同波型的第一控制信号TX1和第二控制信号TX2；对于相位为180度和270度的脉冲PE，可以将第一控制信号TX1和第二控制信号TX2对调并往后移动tX，如图5所示，使对应相位为180度的脉冲PE的预定时间TR的开始时间点t6和相位为180度的脉冲PE的发送时间点t5仍具有第一时间差tX。若不进行此调整，对应相位为180度的脉冲PE的预定时间TR的开始时间点会在t5，使得预定时间TR需要延长tX以保持动态范围。
本申请的第二种方案和上述第一种方案大致相同，差别在于，在第二种方案中飞行时间传感器130的预定时间TR4为固定长度，例如，预定时间TR4为四倍采样区间TN的长度，但不以此限。另外， 控制电路120控制脉冲产生单元110间歇性地发送脉冲组来取代上述第一种方案中的单一脉冲。如图6所示，所述脉冲组包括第一脉冲PE1和第二脉冲PE2，第一脉冲PE1的脉冲长度和第二脉冲PE2的脉冲长度相同，皆为T。第二脉冲PE2的发送时间较同一脉冲组中的第一脉冲PE1落后至少脉冲长度T。也就是说，第二脉冲PE2的发送时间可以较同一脉冲组中的第一脉冲PE1落后2个脉冲长度T以上。
第一脉冲PE1的强度和第二脉冲PE2的强度不同，在本实施例中，刻意使第一脉冲PE1的强度高于第二脉冲PE2的强度，并让预定时间TR4的开始时间点至少往后延到第二脉冲PE2的发送时间点。大致来看，第一脉冲PE1中在预定时间TR4开始之前反射回飞行时间传感器130的能量来不及被采样，在预定时间TR4中，飞行时间传感器130仅会接收到第一脉冲PE1中较慢反射回飞行时间传感器130的能量(即远处信息)；同理，在预定时间TR4中，飞行时间传感器130仅会接收到第二脉冲PE2中较快反射回飞行时间传感器130的能量(即近处信息)。由于第一脉冲PE1的强度较高，因此可提升第一脉冲PE1的远处信息能量，使其和第二脉冲PE2的近处信息能量平衡。因此，通过将第一脉冲PE1和第二脉冲PE2的强度设计为不同大小，可将预定时间TR4中接收到的远处信息能量和近处信息控制在大致相同的程度。
上文的叙述简要地提出了本申请某些实施例的特征，使本领域的技术人员可更全面地理解本申请的多个层面。本领域的技术人员应可了解，其可轻易地利用本申请作为基础，来设计或更动其他流程与结构，以实现与上文所述的实施方式相同的目的和/或达到相同的优点。本领域的技术人员应当明白，这些等效的实施方式仍属于本申请的精神与范围，且其可进行各种改变、替代与更改，而不会悖离本申请的精神与范围。

Claims (42)

  1. 一种基于飞行时间的测距方法，其特征在于，包括：
    从脉冲产生单元间歇性地发送多个第一脉冲，其中所述多个第一脉冲被目标物反射而产生多个第一反射信号；
    使飞行时间传感器对所述多个第一反射信号分别选择性地执行第一信号采样或第二信号采样以产生第一采样结果，其中所述第一信号采样的开始时间点和对应的所述第一脉冲的发送时间点具有第一时间差，且所述第一信号采样持续第一预定时间，以及所述第二信号采样的开始时间点和对应的所述第一脉冲的发送时间点具有第二时间差，且所述第二信号采样持续第二预定时间，且所述第一时间差小于所述第二时间差；
    根据所述第一采样结果，检测所述多个第一脉冲从所述脉冲产生单元到所述飞行时间传感器的飞行时间；以及
    根据所述飞行时间判断所述目标物与参考位置之间的距离。
  2. 如权利要求1所述的测距方法，其中所述第一预定时间包括相邻所述第一预定时间的开始时间点的至少一采样区间；所述第二预定时间包括相邻所述第二预定时间的开始时间点的至少一所述采样区间，所述采样区间具有固定的时间长度。
  3. 如权利要求2所述的测距方法，其中所述采样区间的时间长度等于所述第一脉冲的脉冲长度。
  4. 如权利要求3所述的测距方法，其中所述第二时间差和所述第一时间差的差至少为所述采样区间的时间长度。
  5. 如权利要求3所述的测距方法，其中所述第一预定时间和所述第二预定时间包括相同数目的所述采样区间。
  6. 如权利要求5所述的测距方法，其中所述第一预定时间包括的所述采样区间的数目大于所述第二预定时间包括的所述采样区间的数目。
  7. 如权利要求1所述的测距方法，其中使所述飞行时间传感器对所述多个第一反射信号分别选择性地执行所述第一信号采样或所述第二信号采样的步骤包括：
    依据预定比例来分配所述多个第一反射信号分别对应所述第一信号采样或所述第二信号采样，其中被分配对应所述第一信号采样的所述多个第一反射信号的数目少于被分配对应所述第二信号采样的所述多个第一反射信号的数目。
  8. 如权利要求2至7中任一项所述的测距方法，其中使所述飞行时间传感器产生所述第一采样结果的步骤包括：
    对所述多个第一反射信号分别进行传感以产生响应信号；
    于所述采样区间中，根据第一控制信号选择性地通过第一读出电路接收所述响应信号以产生第一像素输出，以及根据第二控制信号选择性地通过第二第一电路接收所述响应信号以产生第二像素输出，其中所述第二控制信号和所述第一控制信号具有不同的相位；以及
    每隔采样时间间隔采样所述第一像素输出和所述第二像素输出，以根据所述第一像素输出和所述第二像素输出产生所述第一采样结果。
  9. 如权利要求8所述的测距方法，其中所述第一控制信号和所述第二控制信号的相位差是180度。
  10. 如权利要求8所述的测距方法，其中所述采样时间间隔是所述脉冲长度的1/4倍。
  11. 如权利要求1所述的测距方法，另包括：
    从所述脉冲产生单元间歇性地发送多个第二脉冲，其中所述多个第二脉冲被所述目标物反射而产生多个第二反射信号，且所述第二脉冲和所述第一脉冲的相位差是180度；以及
    使所述飞行时间传感器对所述多个第二反射信号分别选择性地执行所述第一信号采样或所述第二信号采样以产生第二采样结果，其中所述第一信号采样的开始时间点和对应的所述第二脉冲的发送时间点具有所述第一时间差，且所述第一信号采样持续所述第一预定时间，以及所述第二信号采样的开始时间点和对应的所述第二脉冲的发送时间点具有所述第二时间差，且所述第二信号采样持续所述第二预定时间。
  12. 如权利要求11所述的测距方法，其中根据所述第一采样结果，检测所述多个第一脉冲从所述脉冲产生单元到所述飞行时间传感器的所述飞行时间的步骤包括：
    根据所述第一采样结果和所述第二采样结果，检测所述飞行时间。
  13. 一种基于飞行时间的测距系统，其特征在于，包括：
    脉冲产生单元；
    控制电路，耦接于所述脉冲产生单元，用以控制所述脉冲产生单元间歇性地发送多个第一脉冲，其中所述多个第一脉冲被目标物反射而产生多个第一反射信号；以及
    飞行时间传感器，由所述控制电路所控制，用以对所述多个第一反射信号分别选择性地执行第一信号采样或第二信号采样以产生第一采样结果，其中所述第一信号采样的开始时间点和对应的所述第一脉冲的发送时间点具有第一时间差，且所述第一信号采样持续第一预定时间，以及所述第二信号采样的开始时间点和对应的所述第一脉冲的发送时间点具有第二时间差，且所述第一时间差小于所述第二时间差，且所述第二信号采样持续第二预定时间，并根据所述第一采样结果，检测所述多个第一脉冲从所述脉冲产生单元到所述飞行时间传感器的飞行时间，以及根据所述飞行时间判断所述目标物与参考位置之间的距离。
  14. 如权利要求13所述的测距系统，其中所述第一预定时间包括相邻所述第一预定时间的开始时间点的至少一采样区间；所述第二预定时间包括相邻所述第二预定时间的开始时间点的至少一所述采样区间，所述采样区间具有固定的时间长度。
  15. 如权利要求14所述的测距系统，其中所述采样区间的时间长度等于所述第一脉冲的脉冲长度。
  16. 如权利要求15所述的测距系统，其中所述第二时间差和所述第一时间差的差至少为所述采样区间的时间长度。
  17. 如权利要求15所述的测距系统，其中所述第一预定时间和所述 第二预定时间包括相同数目的所述采样区间。
  18. 如权利要求17所述的测距系统，其中所述第一预定时间包括的所述采样区间的数目大于所述第二预定时间包括的所述采样区间的数目。
  19. 如权利要求13所述的测距系统，其中所述飞行时间传感器进一步依据预定比例来分配所述多个第一反射信号分别对应所述第一信号采样或所述第二信号采样，其中被分配对应所述第一信号采样的所述多个第一反射信号的数目少于被分配对应所述第二信号采样的所述多个第一反射信号的数目。
  20. 如权利要求14至19中任一项所述的测距系统，其中所述飞行时间传感器包括：
    像素阵列，包括多个像素，其中各像素包括：
    光传感器，用以对所述多个第一反射信号分别进行传感以产生响应信号；
    第一读出电路，用以于所述采样区间中，根据所述控制电路所产生的第一控制信号选择性地传输所述响应信号以产生第一像素输出；以及
    第二读出电路，用以于所述采样区间中，根据所述控制电路所产生的第二控制信号选择性地传输所述响应信号以产生第二像素输出，其中所述第二控制信号和所述第一控制信号具有不同的相位；以及
    处理电路，耦接于所述像素阵列和所述控制电路，用以根据所述控制电路所产生的采样控制信号，每隔采样时间间隔采样所述第一像素输出和所述第二像素输出，以根据所述第一像 素输出和所述第二像素输出产生所述第一采样结果；
  21. 如权利要求20所述的测距系统，其中所述第一控制信号和所述第二控制信号的相位差是180度。
  22. 如权利要求20所述的测距系统，其中所述采样时间间隔是所述脉冲长度的1/4倍。
  23. 如权利要求13所述的测距系统，其中：
    所述控制电路进一步控制所述脉冲产生单元间歇性地发送多个第二脉冲，其中所述多个第二脉冲被所述目标物反射而产生多个第二反射信号，且所述第二脉冲和所述第一脉冲的相位差是180度；以及
    所述飞行时间传感器进一步用以对所述多个第二反射信号分别选择性地执行所述第一信号采样或所述第二信号采样以产生第二采样结果，其中所述第一信号采样的开始时间点和对应的所述第二脉冲的发送时间点具有所述第一时间差，且所述第一信号采样持续所述第一预定时间，以及所述第二信号采样的开始时间点和对应的所述第二脉冲的发送时间点具有所述第二时间差，且所述第二信号采样持续所述第二预定时间。
  24. 如权利要求23所述的测距系统，其中所述飞行时间传感器进一步用以根据所述第一采样结果和所述第二采样结果，检测所述飞行时间。
  25. 一种基于飞行时间的测距方法，其特征在于，包括：
    从脉冲产生单元间歇性地发送多个脉冲组，其中各脉冲组包括第一脉冲和第二脉冲，所述第一脉冲的强度和所述第二脉冲的强度不同，且所述多个脉冲组被目标物反射而产生多个反射信号组；
    使飞行时间传感器对所述多个反射信号组分别执行信号采样以产生采样结果，其中所述信号采样持续预定时间；
    根据所述采样结果，检测所述多个脉冲组从所述脉冲产生单元到所述飞行时间传感器的飞行时间；以及
    根据所述飞行时间测量所述目标物与参考位置之间的距离。
  26. 如权利要求25所述的测距方法，其中所述第一脉冲的强度高于所述第二脉冲的强度。
  27. 如权利要求26所述的测距方法，其中所述预定时间的开始时间点不早于对应的所述脉冲组中的第二脉冲的发送时间点。
  28. 如权利要求27所述的测距方法，其中所述第一脉冲的脉冲长度和所述第二脉冲的脉冲长度相同。
  29. 如权利要求28所述的测距方法，其中所述第二脉冲的发送时间较同一脉冲组中的所述第一脉冲落后不小于所述脉冲长度。
  30. 如权利要求28至29中任一项所述的测距方法，其中所述预定时间包括相邻的第一采样区间和第二采样区间，所述第一采样区间的时间长度和所述第二采样区间的时间长度均等于所述脉 冲长度；使所述飞行时间传感器对所述多个反射信号组分别执行所述信号采样以产生所述采样结果的步骤包括：
    传感所述多个反射信号组以产生响应信号；
    于所述采样区间中，根据第一控制信号选择性地通过第一传输路径接收所述响应信号以产生第一像素输出，以及根据第二控制信号选择性地通过第二传输路径接收所述响应信号以产生第二像素输出，其中所述第二控制信号和所述第一控制信号具有不同的相位，以及至少会有所述第一传输路径或所述第二传输路径接收所述响应信号；以及
    每隔采样时间间隔采样所述第一像素输出和所述第二像素输出，以根据所述第一像素输出和所述第二像素输出产生所述采样结果。
  31. 如权利要求30所述的测距方法，其中所述第一控制信号和所述第二控制信号的相位差是180度。
  32. 如权利要求30所述的测距方法，其中所述第一控制信号于所述第一采样区间和所述第二采样区间具有相同的波形，以及所述第二控制信号于所述第一采样区间和所述第二采样区间具有相同的波形。
  33. 如权利要求30所述的测距方法，其中所述采样时间间隔是所述脉冲长度的1/4倍。
  34. 一种基于飞行时间的测距系统，其特征在于，包括：
    脉冲产生单元；
    控制电路，耦接于所述脉冲产生单元，用以控制所述脉冲产生单元间歇性地发送多个脉冲组，其中各脉冲组包括第一脉冲和第二脉冲，所述第一脉冲的强度和所述第二脉冲的强度不同，且所述多个脉冲组被目标物反射而产生多个反射信号组；以及
    飞行时间传感器，由所述控制电路所控制，用以对所述多个反射信号组分别执行信号采样以产生采样结果，其中所述信号采样持续预定时间；所述飞行时间传感器还根据所述采样结果检测所述多个脉冲组从所述脉冲产生单元到所述飞行时间传感器的飞行时间，以及根据所述飞行时间测量所述目标物与所述测距系统之间的距离。
  35. 如权利要求34所述的测距系统，其中所述第一脉冲的强度高于所述第二脉冲的强度。
  36. 如权利要求35所述的测距系统，其中所述预定时间的开始时间点不早于对应的所述脉冲组中的第二脉冲的发送时间点。
  37. 如权利要求34所述的测距系统，其中所述第一脉冲的脉冲长度和所述第二脉冲的脉冲长度相同。
  38. 如权利要求37所述的测距系统，其中所述第二脉冲的发送时间较同一脉冲组中的所述第一脉冲落后不小于所述脉冲长度。
  39. 如权利要求37至38中任一项所述的测距系统，其中所述飞行时间传感器包括：
    像素阵列，包括多个像素，其中各像素包括：
    传感器，用以传感所述多个反射信号组以产生响应信号；
    第一读出电路，用以于所述预定时间包括的相邻的第一采样区间和第二采样区间的各采样区间中，根据所述控制电路所产生的第一控制信号选择性地传输所述响应信号以产生第一像素输出，其中所述采样区间的时间长度等于所述脉冲长度；以及
    第二读出电路，用以于所述采样区间中，根据所述控制电路所产生的第二控制信号选择性地传输所述响应信号以产生第二像素输出，其中所述第二控制信号和所述第一控制信号具有不同的相位，以及于所述采样区间中，至少会有所述第一读出电路或所述第二读出电路对所述响应信号进行传输；以及
    处理电路，耦接于所述像素阵列和所述控制电路，用以根据所述控制电路所产生的采样控制信号，每隔采样时间间隔采样所述第一像素输出和所述第二像素输出，以及根据所述第一像素输出和所述第二像素输出产生所述采样结果；
  40. 如权利要求39所述的测距系统，其中所述第一控制信号和所述第二控制信号的相位差是180度。
  41. 如权利要求39所述的测距系统，其中所述第一控制信号于所述第一采样区间和所述第二采样区间具有相同的波形，以及所述第二控制信号于所述第一采样区间和所述第二采样区间具有相同的波形。
  42. 如权利要求39所述的测距系统，其中所述采样时间间隔是所述 脉冲长度的1/4倍。
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101034155A (zh) * 2006-03-07 2007-09-12 徕卡测量系统股份有限公司 提高飞行时间测量设备的测量速率
CN109313264A (zh) * 2018-08-31 2019-02-05 深圳市汇顶科技股份有限公司 基于飞行时间的测距方法和测距系统
CN110361715A (zh) * 2019-08-21 2019-10-22 深圳市镭神智能系统有限公司 一种脉冲编码装置、编码方法及激光雷达系统
US20190346541A1 (en) * 2018-05-14 2019-11-14 Rockwell Automation Technologies, Inc. Time of flight system and method using multiple measuring sequences
CN110632578A (zh) * 2019-08-30 2019-12-31 深圳奥锐达科技有限公司 用于时间编码时间飞行距离测量的系统及方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10386487B1 (en) * 2015-12-30 2019-08-20 Argo AI, LLC Geiger-mode LiDAR system having improved signal-to-noise ratio
CN113260874A (zh) * 2018-11-20 2021-08-13 感觉光子公司 用于空间分布式选通的方法和系统

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101034155A (zh) * 2006-03-07 2007-09-12 徕卡测量系统股份有限公司 提高飞行时间测量设备的测量速率
US20190346541A1 (en) * 2018-05-14 2019-11-14 Rockwell Automation Technologies, Inc. Time of flight system and method using multiple measuring sequences
CN109313264A (zh) * 2018-08-31 2019-02-05 深圳市汇顶科技股份有限公司 基于飞行时间的测距方法和测距系统
CN110361715A (zh) * 2019-08-21 2019-10-22 深圳市镭神智能系统有限公司 一种脉冲编码装置、编码方法及激光雷达系统
CN110632578A (zh) * 2019-08-30 2019-12-31 深圳奥锐达科技有限公司 用于时间编码时间飞行距离测量的系统及方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3951432A4 *

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