WO2021248892A1 - 一种距离测量系统及测量方法 - Google Patents

一种距离测量系统及测量方法 Download PDF

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WO2021248892A1
WO2021248892A1 PCT/CN2020/141729 CN2020141729W WO2021248892A1 WO 2021248892 A1 WO2021248892 A1 WO 2021248892A1 CN 2020141729 W CN2020141729 W CN 2020141729W WO 2021248892 A1 WO2021248892 A1 WO 2021248892A1
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Prior art keywords
time
pulse
distance measurement
control
processing circuit
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PCT/CN2020/141729
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English (en)
French (fr)
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李国花
何燃
苏健
朱亮
闫敏
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深圳奥锐达科技有限公司
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Publication of WO2021248892A1 publication Critical patent/WO2021248892A1/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
    • 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
    • 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
    • G01S7/495—Counter-measures or counter-counter-measures using electronic or electro-optical means

Definitions

  • This application relates to the field of optical measurement technology, and in particular to a distance measurement system and measurement method.
  • the time of flight principle can be used to measure the distance of the target to obtain a depth image containing the target depth value.
  • the distance measurement system based on the time of flight principle has been widely used in consumer electronics, unmanned aerial vehicles, AR/VR and other fields.
  • a distance measurement system based on the time-of-flight principle usually includes a transmitter and a collector. The transmitter emits a pulsed beam to illuminate the target field of view and the collector uses the collector to collect the reflected beam reflected by the object in the target field of view, and calculate the beam from emission to reflection Receive the time required to calculate the distance to the target object.
  • the collector includes a pixel array, especially a pixel array including a single-photon avalanche photodiode (SPAD).
  • SPAD single-photon avalanche photodiode
  • the photon in the front part of the reflected beam The faster incidence into the SPAD array saturates multiple SPADs, and the subsequent incident photons are less likely to be collected by the SPAD, leading to the advancement of the pulse peak position. Or, under strong ambient light conditions, a large number of ambient photons are incident on the SPAD array to saturate multiple SPADs, and then the probability of signal photons being collected by the SPAD is reduced, resulting in distortion of the formed received waveform and inability to obtain accurate flight time. The resulting distortion of the received waveform is collectively called the pile-up phenomenon.
  • the purpose of the present application is to provide a distance measurement system and measurement method to solve at least one of the above-mentioned background technical problems.
  • An embodiment of the present application provides a distance measurement system, including: a transmitter configured to emit a time-coded optical signal pulse train; a collector configured to collect photons in the optical signal pulse train reflected back by an object Control and processing circuit, connected with the transmitter and the collector, synchronize the trigger signal of the transmitter and the collector, and generate a timing signal synchronized with the trigger signal to regulate the timing of the TDC circuit, and record all
  • the incident time of the photons is used to form a frame period single photon counting sequence; wherein the control and processing circuit controls the emission time of the optical signal pulse train to have a misalignment time with respect to the timing signal, and is based on the frame period single photon count sequence. Count the time series to draw a histogram to determine the flight time.
  • the misalignment time is random and obeys a Gaussian distribution
  • the standard deviation of the Gaussian distribution is configured as a random number of the pulse width of the light pulse.
  • the transmitter is configured as a light source array composed of a plurality of light sources, and each light source in the light source array emits light signal pulse trains with different time codes.
  • control and processing circuit performs convolution calculation cross-correlation based on the pre-stored time-coded filter kernel and the drawn histogram to determine the pulse peak position, and determines the flight time according to the pulse peak position; Or, based on the time coding mode of the optical signal pulse, a histogram is drawn by a time coding continuous single photon count and superposition mode, and the flight time is determined according to the pulse peak value in the histogram.
  • the transmitter emits an optical signal pulse train with a double random or pseudo-random time code, the emission pulse is divided into a plurality of pulse groups, and each of the pulse groups contains a plurality of pulses, the pulse The groups are transmitted in the form of a first random time code; the pulse groups are transmitted in the form of a second random time code.
  • control and processing circuit controls the transmitter to have a misalignment time relative to the timing signal when emitting each group of light pulses, and the misalignment time is in an encoding mode.
  • the embodiment of the present application also provides a distance measurement method, which includes the following steps:
  • control and processing circuit controls the emission time of the optical signal pulse train to have a misalignment time with respect to the timing signal, and draws a histogram based on the frame period single photon count time sequence to determine the flight time.
  • the misalignment time is random and obeys a Gaussian distribution
  • the standard deviation of the Gaussian distribution is configured as a random number of the pulse width of the light pulse.
  • the transmitter emits an optical signal pulse train with a double random or pseudo-random time code, the emission pulse is divided into a plurality of pulse groups, and each of the pulse groups contains a plurality of pulses, the pulse The groups are transmitted in the form of a first random time code; the pulse groups are transmitted in the form of a second random time code.
  • the method further includes the step of pre-storing a filter core based on time coding, the control and processing circuit performs convolution calculation cross-correlation based on the filter core and the drawn histogram to determine the pulse peak position, and according to the The pulse peak position determines the flight time; or, the control and processing circuit draws a histogram based on the time-coding mode of the optical signal pulse by using the time-coded continuous single-photon count superposition method, and determines the flight according to the pulse peak value in the histogram time.
  • An embodiment of the present application provides a distance measurement system, including: a transmitter configured to emit a time-coded optical signal pulse train; a collector configured to collect photons in the reflected optical signal pulse train; control and processing
  • the circuit is connected to the transmitter and the collector, synchronizes the trigger signal of the transmitter and the collector, generates a timing signal synchronized with the trigger signal to regulate the timing of the TDC circuit, and records the incident time of photons to form a frame period single photon counting timing string; among them,
  • the control and processing circuit controls the emission time of the optical signal pulse train to have a misalignment time relative to the timing signal, and draws a histogram based on the single photon count sequence of the frame period to determine the flight time.
  • the embodiments of the application ensure that all pulse trains in a single frame period will be received and there will be no impulse response in adjacent frame periods, improve the anti-interference ability of the system, and adjust the relative timing signal of the optical pulse after the timing is started Dislocation emission can effectively solve the pile-up phenomenon.
  • Fig. 1 is a schematic diagram of a distance measurement system according to an embodiment of the present application.
  • Fig. 2 is a schematic diagram of a staggered emission time-coded pulse modulation scheme of a distance measurement system according to an embodiment of the present application.
  • Fig. 3 is a schematic diagram of another dislocation transmission time-coded pulse modulation scheme of the distance measurement system according to an embodiment of the present application.
  • Fig. 4 is a flowchart of a distance measurement method according to another embodiment of the present application.
  • connection can be used for fixing or circuit connection.
  • first and second are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with “first” and “second” may explicitly or implicitly include one or more of these features. In the description of the embodiments of the present application, "a plurality of” means two or more than two, unless otherwise specifically defined.
  • FIG. 1 is a schematic diagram of a distance measurement system according to an embodiment of the application.
  • the distance measurement system 10 includes a transmitter 11, a collector 12 and a control and processing circuit 13.
  • the transmitter 11 is used to emit a light beam 30 to the target area 20.
  • the light beam is emitted into the target area space to illuminate the target object in the space. At least part of the emitted light beam 30 is reflected by the target area 20 to form a reflected light beam 40.
  • the reflected light beam 40 At least part of the light beam in is received by the collector 12, and the control and processing circuit 13 is connected to the transmitter 11 and the collector 12 respectively, and synchronizes the trigger signal of the transmitter 11 and the collector 12 to calculate the time required for the beam from emission to reception, That is, the flight time t between the emitted light beam 30 and the reflected light beam 40, and further, the distance D of the corresponding point on the target object can be calculated by the following formula:
  • the transmitter 11 includes a light source 111, a transmitting optical element 112, a driver 113, and the like.
  • the light source 111 may be a light emitting diode (LED), a laser diode (LD), an edge emitting laser (EEL), a vertical cavity surface emitting laser (VCSEL), etc., or a one-dimensional or two-dimensional light source array composed of multiple light sources;
  • the light source array is a VCSEL array light source chip formed by generating multiple VCSEL light sources on a single semiconductor substrate, and the arrangement of the light sources in the light source array may be regular or irregular.
  • the light beam emitted by the light source 111 may be visible light, infrared light, ultraviolet light, or the like.
  • the light source 111 emits light beams outward under the control of the driver 113.
  • the light source 111 emits a pulsed beam at a certain frequency (pulse period) under the control of the driver 113, which can be used in direct time-of-flight (Direct TOF) measurement, and the frequency is set according to the measurement distance.
  • a part of the control and processing circuit 13 or a sub-circuit independent of the control and processing circuit 13 can also be used to control the light source 111 to emit light beams.
  • the emitting optical element 112 receives the light beam emitted from the light source 111, shapes it and projects it to the target area.
  • the transmitting optical element 112 receives the pulsed beam from the light source 111, and performs optical modulation of the pulsed beam, such as diffraction, refraction, reflection, etc., and then emits the modulated beam into the space, such as a focused beam, Flood light beam, structured light beam, etc.
  • the transmitting optical element 112 may be one or more combinations of lenses, liquid crystal elements, diffractive optical elements, microlens arrays, metasurface optical elements, masks, mirrors, MEMS galvanometers, and the like.
  • the collector 12 includes a pixel unit 121, a filter unit 122, and a receiving optical element 123.
  • the receiving optical element 123 is used to receive at least part of the light beam reflected by the target and guide it to the pixel unit 121.
  • the filter unit 122 is used to filter out background light or Stray light.
  • the pixel unit 121 includes a two-dimensional pixel array composed of multiple pixels; in some embodiments, the pixel unit 121 is a pixel array composed of a single photon avalanche photodiode (SPAD), and the SPAD can respond to incident single photons and output instructions
  • the signal of the corresponding arrival time of the received photons at each SPAD is realized by using, for example, the time-correlated single photon counting method (TCSPC) to realize the collection of the weak light signal and the calculation of the flight time.
  • TCSPC time-correlated single photon counting method
  • the control and processing circuit 13 synchronizes the trigger signals of the transmitter 11 and the collector 12, processes the photon signal of the pixel collection beam, and calculates the distance information of the target to be measured based on the flight time of the reflected beam.
  • the SPAD outputs a photon signal in response to a single incident photon
  • the control and processing circuit 13 receives the photon signal and performs signal processing to obtain the flight time of the light beam.
  • the control and processing circuit 13 calculates the number of collected photons to form continuous time bins. These time bins are connected together to form a statistical histogram for reproducing the time series of the reflected light beam. Peak matching and filter detection are used to identify the reflected light beam from Flight time from transmission to reception.
  • control and processing circuit 13 includes a readout circuit composed of one or more of a signal amplifier, a time-to-digital converter (TDC), a digital-to-analog converter (ADC) and other devices (not shown in the figure). ). These circuits can be integrated with the pixels, and can also be used as a part of the control and processing circuit 13. For ease of description, they will be collectively regarded as a part of the control and processing circuit 13. It can be understood that the control and processing circuit 13 may be an independent dedicated circuit, such as a dedicated SOC chip, an FPGA chip, an ASIC chip, etc., and may also include a general-purpose processing circuit.
  • the distance measurement system 10 further includes a memory for storing a pulse encoding program, and the encoding program is used to control the excitation time, emission frequency, etc. of the light beam emitted by the light source 111.
  • the distance measurement system 10 may also include a color camera, an infrared camera, an IMU, and other devices.
  • the combination of these devices can achieve richer functions, such as 3D texture modeling, infrared face recognition, SLAM and other functions.
  • the transmitter 11 and the collector 12 can also be arranged in a coaxial form, that is, the two are realized by optical devices with reflection and transmission functions, such as a half mirror.
  • Fig. 2 is a schematic diagram of the dislocation transmission time-coded pulse modulation of the distance measurement system according to an embodiment of the present application.
  • the control and processing circuit 13 includes a TDC circuit and a histogram circuit for drawing a histogram reflecting the pulse waveform emitted by the light source in the transmitter. Further, the flight time can also be calculated based on the histogram, and finally the result Perform output.
  • the received waveform reflecting the pulse waveform emitted by the light source in the transmitter is drawn.
  • the received waveform is basically similar in shape to the transmitted pulse waveform.
  • the received waveform represents the number of photons in the reflected pulse incident on the pixel array.
  • the SPAD array since the SPAD array enters the dead time after receiving the photons and no longer detects the photons, it is easy to cause the distortion of the formed received waveform to produce pile-up phenomenon. The following will describe how to solve this problem through some embodiments to improve the distance measurement system Accuracy.
  • the transmitter 21 is configured to transmit an optical signal pulse train with a time code toward the target area, where the time code can be a regular time code or a random time code; it can be a single time code or a double time code.
  • the time coding technology used can refer to the relevant content in Chinese Patent Application Publication No. CN201910814078.X, which will not be repeated in the embodiments of this application).
  • the collector 22 is configured to collect part of the photons in the light signal pulse train reflected back from the target.
  • the TDC circuit processes and records the corresponding incident time of each incident photon to form a frame period single photon counting sequence; the histogram circuit is based on the frame period Single-photon counting time series draws a histogram; the control and processing circuit is used to determine the pulse peak position of the pulse waveform in the histogram, and determine the flight time according to the pulse peak position.
  • the control and processing circuit 13 synchronizes the trigger signals of the transmitter 21 and the collector 22 to calculate the time required for the light beam from emission to reception, and generates a timing signal synchronized with the trigger signal to regulate the TDC circuit to start timing, which is used to record the pulses in the pulse beam. The time taken by a photon from emission to reception.
  • the control and processing circuit 13 controls the transmitter 21 to emit the optical signal pulse train in a staggered position relative to the timing signal after receiving the trigger signal, that is, the emission time of the optical signal pulse train is staggered with respect to the timing signal.
  • the dislocation time is random (pseudo-random), and the dislocation time obeys a Gaussian distribution, and the standard deviation of the Gaussian distribution is configured as a random number of the pulse width of the light pulse.
  • the light pulse presents a Gaussian distribution in time.
  • the misalignment time is set to obey the Gaussian distribution to ensure that a large number of photons in the front of the light pulse can still be drawn in the histogram circuit. Meet the histogram of Gaussian distribution, which can locate the wave crest and effectively solve the pile-up phenomenon.
  • the frame period T is set to That is, when the largest target is located at the maximum measurement distance, the time required for the last pulse in the pulse train from the start of transmission by the transmitter 21 to the end of the reception by the collector 22 is exactly t 1 , which ensures that it is in a single frame period All the bursts within will be received and there will be no impulse response in adjacent frame periods.
  • control and processing circuit 13 controls the transmitter 21 to emit the light signal pulse train when there is a misalignment time R 1 relative to the timing signal, and the collector starts to collect the reflected photons after receiving the trigger signal, and the timing signal of the synchronization trigger signal controls the TDC circuit Start timing and record the time from emission to reception of photons in the light pulse, so as to ensure that all photons in the reflected light pulse can be detected.
  • the filter core based on time coding is pre-stored, and the control and processing circuit 13 performs convolution calculation cross-correlation based on the filter core and the histogram drawn in the histogram circuit to determine the pulse peak position, and determine the pulse peak position according to the pulse peak position. flight duration.
  • the histogram circuit draws the histogram according to the time coding mode of the transmitted light signal pulse by using the time coding continuous single photon count superposition method, that is, the current histogram to be drawn is used as the starting unit, and the time coding is used to draw the histogram.
  • the photon count value of the corresponding time unit in the time series string is superimposed, and the superimposed photon count is the photon count value of the starting time unit.
  • the time code of the transmitted light signal pulse train is [ ⁇ t 1 , ⁇ t 1 + ⁇ t 2 , ⁇ t 1 + ⁇ t 2 + ⁇ t 3 ,..., ⁇ t 1 + ⁇ t 2 ...+ ⁇ t (n-1) ].
  • the time unit to be drawn is the starting unit, and the subsequent sequence string is separated from the starting unit by ⁇ t 1 , ⁇ t 1 + ⁇ t 2 , ⁇ t 1 + ⁇ t 2 + ⁇ t 3 , ..., ⁇ t 1 + ⁇ t 2 ... + ⁇ t
  • the photon count values of all time units of n-1) are sequentially superimposed with the initial photon count value, and the superimposed photon count is used as the value of the time unit in the histogram. Determine the pulse peak position in the histogram, and determine the flight time based on the pulse peak position.
  • Fig. 3 is a schematic diagram of a staggered emission time-coded pulse modulation according to another embodiment of the present application.
  • the transmitter 31 transmits an optical signal pulse train with double random (pseudo-random) time coding (the time coding technology used can refer to the relevant content in Chinese Patent Application Publication No.
  • each pulse group contains multiple pulses
  • the collector 32 will successively receive the photons in the pulse train reflected by the target after t time, in order to ensure that the pulse beams in the adjacent two frame periods are prevented from interacting with each other.
  • the frame period T is set to That is, when the largest target is located at the maximum measurement distance, the time required for the last pulse in the pulse train from the start of transmission by the transmitter 31 until the end of the reception by the collector 32 is exactly t 1 , which ensures that it is in a single frame period All the bursts within will be received and there will be no impulse response in adjacent frame periods.
  • the filter core based on dual time coding is pre-stored, and the control and processing circuit 13 performs convolution calculation cross-correlation based on the filter core and the histogram drawn in the histogram circuit to determine the pulse peak position, and according to the pulse peak position Determine the flight time.
  • the histogram is drawn by the mode of time coding superimposed and then fused. That is to say, it is divided into two steps for drawing (the two steps are in no order).
  • the first step is to superimpose the photon counts of the corresponding time units between the single photon counting sequence series of N pulse group cycles; the second step is to add the The total time sequence obtained is superimposed according to the first time code of the transmitted pulse in the pulse group.
  • the transmitter is configured as a light source array composed of multiple light sources.
  • the light pulses emitted by adjacent light sources will also produce crosstalk when they are reflected by the target and received by the collector.
  • each light source can be set to emit Different time-coded optical signal pulse trains.
  • the light source is configured to emit a light signal pulse train with a double time code, wherein the pulse group emits the pulse train with the same first random time code, and the group has a different random time code form to change the group to the group. Realizing that each light source emits light signal pulse trains with different time codes can also effectively avoid crosstalk.
  • the control and processing circuit controls the transmitter to adjust the time when the light pulse is emitted relative to the timing signal after receiving the trigger signal, which can solve the pile-up problem.
  • FIG. 4 is a flowchart of the distance measurement method. The method includes the following steps:
  • the timing signal of the control and processing circuit is used to regulate the timing of the TDC circuit, and the incident time of the photons is recorded to form a single-photon counting sequence string in the frame period;
  • control and processing circuit controls the emission time of the optical signal pulse train to have a misalignment time relative to the timing signal, and draws a histogram based on the single photon counting sequence of the frame period to determine the flight time.
  • the misalignment time is random and obeys the Gaussian distribution
  • the standard deviation of the Gaussian distribution is configured as a random number of the pulse width of the light pulse.
  • the transmitter emits a light signal pulse train with a double random or pseudo-random time code
  • the transmitted pulses are divided into multiple pulse groups, each pulse group contains multiple pulses, and the pulse group is coded with a first random time Transmit in the form of a second random time code between the pulse groups; among them, the control and processing circuit controls the transmitter to have a relative timing signal misalignment time when emitting each group of light pulses, and the misalignment time is also in the encoding mode ,
  • the misalignment time is random (pseudo-random), and the misalignment time obeys a Gaussian distribution, and the standard deviation of the Gaussian distribution is configured as a random number of the pulse width of the light pulse.
  • the method further includes the step of pre-storing a filter core based on time coding, and the control and processing circuit performs convolution calculation based on the filter core and the drawn histogram to determine the pulse peak position, and determine the flight according to the pulse peak position. time;
  • the distance measurement method of this embodiment adopts the above-mentioned distance measurement system for distance measurement, and its technical solution is the same as the above-mentioned distance measurement system, so it will not be repeated here.
  • this application further proposes a solution to the pile-up phenomenon on the basis of effectively solving the interference problem, which improves the accuracy of the distance measurement system, and at the same time enhances the anti-interference characteristics of the system and effectively increases the frame rate. .
  • the implementation of this application also provides a storage medium for storing a computer program, which at least executes the distance measurement method described in the foregoing embodiment when the computer program is executed.
  • the storage medium may be implemented by any type of volatile or non-volatile storage device, or a combination thereof.
  • the non-volatile memory can be read-only memory (ROM, Read Only Memory), programmable read-only memory (PROM, Programmable Read-Only Memory), and erasable programmable read-only memory (EPROM, Erasable Programmable Read-Only).
  • Memory Electrically Erasable Programmable Read-Only Memory (EEPROM, Electrically Erasable Programmable Read-Only Memory), Magnetic Random Access Memory (FRAM, Ferromagnetic Random Access Memory), Flash Memory (Flash Memory), Magnetic Surface Memory, Optical Disk, Or CD-ROM (Compact Disc Read-Only Memory); magnetic surface memory can be disk storage or tape storage.
  • the volatile memory may be a random access memory (RAM, Random Access Memory), which is used as an external cache.
  • RAM random access memory
  • SRAM static random access memory
  • SSRAM synchronous static random access memory
  • DRAM Dynamic Random Access Memory
  • SDRAM Synchronous Dynamic Random Access Memory
  • DDRSDRAM Double Data Rate Synchronous Dynamic Random Access Memory
  • ESDRAM Enhanced Synchronous Dynamic Random Access Memory Access memory
  • SLDRAM synchronous connection dynamic random access memory
  • SyncLink Dynamic Random Access Memory direct memory bus random access memory
  • DRRAM Direct Rambus Random Access Memory
  • the storage media described in the embodiments of the present application are intended to include, but are not limited to, these and any other suitable types of storage.
  • An embodiment of the present application also provides a computer device, the computer device including a memory, a processor, and a computer program stored on the memory and running on the processor, wherein the processor executes the computer
  • the program implements at least the distance measurement method described in the foregoing embodiment scheme.

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Abstract

一种距离测量系统及方法，该距离测量系统（10）包括：发射器（11），经配置以发射具有时间编码的光信号脉冲串；采集器（12），经配置以采集反射回的光信号脉冲串中的光子；控制和处理电路（13），与发射器（11）和采集器（12）连接，同步发射器（11）与采集器（12）的触发信号，产生与触发信号同步的计时信号调控TDC电路计时，记录光子的入射时间以形成帧周期单光子计数时序串；其中，控制和处理电路（13）控制光信号脉冲串的发射时间相对计时信号存在错位时间，并基于帧周期单光子计数时序串绘制直方图，以确定飞行时间。该系统确保在单帧周期内所有的脉冲串均会被接收且不会有相邻帧周期内的脉冲响应，提高了系统的抗干扰能力，且通过开始计时后调控光脉冲相对计时信号错位发射，可有效解决pile-up现象。

Description

一种距离测量系统及测量方法
本申请要求于2020年6月12日提交中国专利局，申请号为202010537808.9，发明名称为“一种距离测量系统及测量方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及光学测量技术领域，尤其涉及一种距离测量系统及测量方法。
背景技术
利用飞行时间原理(TOF，Time of Flight)可以对目标进行距离测量，以获取包含目标深度值的深度图像，而基于飞行时间原理的距离测量系统已被广泛应用于消费电子、无人架驶、AR/VR等领域。基于飞行时间原理的距离测量系统通常包括发射器和采集器，利用发射器发射脉冲光束照射目标视场并利用采集器采集被目标视场中的物体反射回的反射光束，计算光束由发射到反射接收所需要的时间来计算目标物体的距离。
目前基于飞行时间原理的距离测量系统中，采集器包括有像素阵列，特别是包括单光子雪崩光电二极管(SPAD)的像素阵列，当发射光束中的一个光子入射到SPAD时，即可触发雪崩事件输出信号用于记录光子到达SPAD的时间，基于此计算光束从发射到接收所需要的时间。但是由于SPAD接收一个光子后需要等待死区时间(deadtime)再接收下一个光子，当待测目标离SPAD阵列距离较近时，或者待测目标具有高反射率时，反射光束中前部的光子更快的入射到SPAD阵列中使多个SPAD饱和，而后续入射的光子被SPAD采集到的概率降低，导致脉冲峰值位置提前。或者，在强环境光条件下，大量的环境光子入射到SPAD阵列中使多个SPAD饱和，而后信号光子被SPAD采集到的概率降低， 导致形成的接收波形失真，无法获得准确的飞行时间，以上产生的接收波形失真的情况统称为pile-up(堆积)现象。
发明内容
本申请的目的在于提供一种距离测量系统及测量方法，以解决上述背景技术问题中的至少一种问题。
本申请实施例提供一种距离测量系统，包括：发射器，经配置以发射具有时间编码的光信号脉冲串；采集器，经配置以采集被物体反射回的所述光信号脉冲串中的光子；控制和处理电路，与所述发射器以及所述采集器连接，同步所述发射器与所述采集器的触发信号，并产生与所述触发信号同步的计时信号调控TDC电路计时，记录所述光子的入射时间以形成帧周期单光子计数时序串；其中，所述控制和处理电路控制所述光信号脉冲串的发射时间相对所述计时信号存在错位时间，并基于所述帧周期单光子计数时序串绘制直方图，以确定飞行时间。
在一些实施例中，所述错位时间是随机的，且服从高斯分布，所述高斯分布的标准差被配置为所述光脉冲的脉冲宽度的随机数。
在一些实施例中，所述发射器被配置为由多个光源组成的光源阵列，所述光源阵列中的每个光源均发射具有不同时间编码的光信号脉冲串。
在一些实施例中，所述控制和处理电路基于预存储的基于时间编码的滤波核与绘制的直方图进行卷积计算互相关以确定脉冲峰值位置，并根据所述脉冲峰值位置确定飞行时间；或者，基于所述光信号脉冲的时间编码方式，采用时间编码连续单光子计数叠加的方式绘制直方图，根据直方图中的脉冲峰值确定飞行时间。
在一些实施例中，所述发射器发射具有双重随机或伪随机时间编码的光信号脉冲串，所述发射脉冲分成多个脉冲组，每个所述脉冲组内包含多个脉冲，所述脉冲组以第一随机时间编码的形式发射；所述脉冲组之间以第二随机时间 编码的形式进行发射。
在一些实施例中，所述控制和处理电路控制发射器在发射每组光脉冲时具有相对计时信号的错位时间，所述错位时间呈编码模式。
本申请实施例还提供一种距离测量方法，包括如下步骤：
S40、控制发射器发射具有时间编码的光信号脉冲串；
S41、控制采集器采集被物体反射回的光信号脉冲串中的光子；
S42、通过控制和处理电路产生计时信号调控TDC电路计时，记录所述光子的入射时间以形成帧周期单光子计数时序串；
其中，控制和处理电路控制所述光信号脉冲串的发射时间相对所述计时信号存在错位时间，并基于所述帧周期单光子计数时序串绘制直方图，以确定飞行时间。
在一些实施例中，所述错位时间是随机的，且服从高斯分布，高斯分布的标准差被配置为光脉冲的脉冲宽度的随机数。
在一些实施例中，所述发射器发射具有双重随机或伪随机时间编码的光信号脉冲串，所述发射脉冲分成多个脉冲组，每个所述脉冲组内包含多个脉冲，所述脉冲组以第一随机时间编码的形式发射；所述脉冲组之间以第二随机时间编码的形式进行发射。
在一些实施例中，还包括步骤：预存储基于时间编码的滤波核，所述控制和处理电路基于所述滤波核与绘制的直方图进行卷积计算互相关以确定脉冲峰值位置，并根据所述脉冲峰值位置确定飞行时间；或者，所述控制和处理电路基于所述光信号脉冲的时间编码方式，采用时间编码连续单光子计数叠加的方式绘制直方图，根据直方图中的脉冲峰值确定飞行时间。
本申请实施例提供一种距离测量系统，包括：发射器，经配置以发射具有时间编码的光信号脉冲串；采集器，经配置以采集反射回的光信号脉冲串中的光子；控制和处理电路，与发射器和采集器连接，同步发射器与采集器的触发信号，产生与触发信号同步的计时信号调控TDC电路计时，记录光子的入射时 间以形成帧周期单光子计数时序串；其中，控制和处理电路控制光信号脉冲串的发射时间相对计时信号存在错位时间，并基于帧周期单光子计数时序串绘制直方图，以确定飞行时间。本申请实施例确保了在单帧周期内所有的脉冲串均会被接收且不会有相邻帧周期内的脉冲响应，提高系统的抗干扰能力，且通过开始计时后调控光脉冲相对计时信号错位发射，可有效解决pile-up现象。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1是根据本申请一个实施例距离测量系统的示意图。
图2是根据本申请一个实施例距离测量系统的错位发射时间编码脉冲调制方案的示意图。
图3是根据本申请一个实施例距离测量系统的另一错位发射时间编码脉冲调制方案的示意图。
图4根据本申请另一个实施例距离测量方法的流程图示。
具体实施方式
为了使本申请实施例所要解决的技术问题、技术方案及有益效果更加清楚明白，以下结合附图及实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本申请，并不用于限定本申请。
需要说明的是，当元件被称为“固定于”或“设置于”另一个元件，它可以直接在另一个元件上或者间接在该另一个元件上。当一个元件被称为是“连接于”另一个元件，它可以是直接连接到另一个元件或间接连接至该另一个元件上。另外，连接即可以是用于固定作用也可以是用于电路连通作用。
需要理解的是，术语“长度”、“宽度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请实施例和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多该特征。在本申请实施例的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
图1所示为本申请一个实施例的距离测量系统示意图，该距离测量系统10包括发射器11、采集器12以及控制和处理电路13。其中，发射器11用于向目标区域20发射光束30，该光束发射至目标区域空间中以照明空间中的目标物体，至少部分发射光束30经目标区域20反射后形成反射光束40，反射光束40中的至少部分光束被采集器12接收，控制和处理电路13分别与发射器11以及采集器12连接，同步发射器11与采集器12的触发信号以计算光束从发射到接收所需要的时间，即发射光束30与反射光束40之间的飞行时间t，进一步，目标物体上对应点的距离D可由下式计算出：
D＝c·t/2       (1)
其中，c为光速。
发射器11包括光源111、发射光学元件112以及驱动器113等。光源111可以是发光二极管(LED)、激光二极管(LD)、边发射激光器(EEL)、垂直腔面发射激光器(VCSEL)等，也可以是由多个光源组成的一维或二维光源阵列；优选地，光源阵列是在单块半导体基底上生成多个VCSEL光源以形成的VCSEL阵列光源芯片，光源阵列中光源的排列方式可以是规则的也可以是不规则的。光源111所发射的光束可以是可见光、红外光、紫外光等。光源111在驱动器113的控制下向外发射光束。在一些实施例中，光源111在驱动器113的控制下以一 定频率(脉冲周期)向外发射脉冲光束，可以用于直接飞行时间(Direct TOF)测量中，频率根据测量距离进行设定。可以理解的是，还可以利用控制和处理电路13中的一部分或者独立于控制和处理电路13存在的子电路来控制光源111发射光束。
发射光学元件112接收来自光源111发射的光束并整形后投射到目标区域。在一些实施例中，发射光学元件112接收来自光源111的脉冲光束，并将脉冲光束进行光学调制，比如衍射、折射、反射等调制，随后向空间中发射被调制后的光束，比如聚焦光束、泛光光束、结构光光束等。发射光学元件112可以是透镜、液晶元件、衍射光学元件、微透镜阵列、超表面(Metasurface)光学元件、掩膜板、反射镜、MEMS振镜等形式中的一种或多种组合。
采集器12包括像素单元121、过滤单元122和接收光学元件123，接收光学元件123用于接收由目标反射回的至少部分光束并引导到像素单元121上，过滤单元122用于滤除背景光或杂散光。像素单元121包括由多个像素组成的二维像素阵列；在一些实施例中，像素单元121是由单光子雪崩光电二极管(SPAD)组成像素阵列，SPAD可以对入射的单个光子进行响应并输出指示所接收光子在每个SPAD处相应到达时间的信号，利用诸如时间相关单光子计数法(TCSPC)实现对微弱光信号的采集以及飞行时间的计算。
控制和处理电路13同步发射器11与采集器12的触发信号，对像素采集光束的光子信号进行处理，并基于反射光束的飞行时间计算出待测目标的距离信息。在一些实施例中，SPAD对入射的单个光子进行响应而输出光子信号，控制和处理电路13接收光子信号并进行信号处理获取光束的飞行时间。具体的，控制和处理电路13计算采集光子的数量形成连续的时间bin，这些时间bin连在一起形成统计直方图用于重现反射光束的时间序列，利用峰值匹配和滤波检测识别出反射光束从发射到接收的飞行时间。在一些实施例中，控制和处理电路13包括信号放大器、时数转换器(TDC)、数模转换器(ADC)等器件中的一种或多种组成的读出电路(图中未示出)。这些电路即可以与像素整合在一起， 也可以作为控制和处理电路13的一部分，为便于描述，将统一视作控制和处理电路13的一部分。可以理解的是，控制和处理电路13可以是独立的专用电路，比如专用SOC芯片、FPGA芯片、ASIC芯片等等，也可以包含通用处理电路。
在一些实施例中，距离测量系统10还包括存储器，用于存储脉冲编码程序，利用编码程序控制光源111发射光束的激发时间、发射频率等。
在一些实施例中，距离测量系统10还可以包括彩色相机、红外相机、IMU等器件，与这些器件的组合可以实现更加丰富的功能，比如3D纹理建模、红外人脸识别、SLAM等功能。
在一些实施例中，发射器11与采集器12也可以被设置成共轴形式，即二者之间通过具备反射及透射功能的光学器件来实现，比如半透半反镜等。
图2所示是本申请一个实施例距离测量系统错位发射时间编码脉冲调制的示意图。在一些实施例中，控制和处理电路13包括TDC电路和直方图电路，用于绘制反映发射器中光源所发射脉冲波形的直方图，进一步地，也可以根据直方图计算飞行时间，最后将结果进行输出。
在直方图电路中绘制出反映发射器中光源所发射脉冲波形的接收波形，通常接收波形与发射的脉冲波形在形状上基本相似，接收波形表示入射到像素阵列中的反射脉冲中的光子数量。但是，由于SPAD阵列在接收光子后进入死区时间而不再检测光子，容易导致形成的接收波形失真产生pile-up现象，下面将通过一些实施例描述如果解决这一问题，以提高距离测量系统的准确性。
具体的，发射器21经配置以朝向目标区域发射具有时间编码的光信号脉冲串，其中时间编码可以是规则时间编码的也可以是随机时间编码；可以是单重时间编码也可以是双重时间编码(所用时间编码技术可以参考中国专利申请公开第CN201910814078.X号中的相关内容，在本申请实施例中不再赘述)。采集器22经配置以采集从目标反射回的光信号脉冲串中的部分光子，TDC电路处理并记录每个入射光子的相应入射时间以形成帧周期单光子计数时序串；直方图电路基于帧周期单光子计数时序串绘制直方图；控制和处理电路用于确定直方 图中脉冲波形的脉冲峰值位置，并根据脉冲峰值位置确定飞行时间。控制和处理电路13同步发射器21与采集器22的触发信号以计算光束从发射到接收所需要的时间，并且产生与触发信号同步的计时信号调控TDC电路开始计时，用于记录脉冲光束中的光子从发射到被接收所用的时间。
控制和处理电路13控制发射器21在接收到触发信号后相对计时信号错位发射光信号脉冲串，即光信号脉冲串的发射时间相对计时信号存在错位时间。其中，错位时间是随机(伪随机)的，并且该错位时间服从高斯分布，高斯分布的标准差被配置为光脉冲的脉冲宽度的随机数。光脉冲在时间上呈现高斯分布，当采集器接收到大量的脉冲前部的光子数时，导致直方图电路中绘制的直方图波形过窄而不满足高斯分布，无法准确进行波峰定位。因此，在本申请实施例中通过开始计时后调控光脉冲相对计时信号错位发射，将错位时间设置为服从高斯分布以确保在直方图电路中接收到大量光脉冲前部的光子时仍能够绘制出满足高斯分布的直方图，从而可以进行波峰定位，有效的解决pile-up现象。
在一些实施例中，如图2所示，发射器21发射具有随机(伪随机)时间编码的光信号脉冲串，该随机时间编码为[Δt 1，Δt 1+Δt 2，Δt 1+Δt 2+Δt 3，…，Δt 1+Δt 2…+Δt (n-1)]，其中，Δt i表示第i个脉冲与第(i+1)个脉冲的时间间隔，i＝1，2，…(n-1)。若被测目标在D处，对应的飞行时间是t，则在t时间后采集器22将相继接收到被目标反射的脉冲串中的光子。为了保证避免相邻两帧周期中脉冲光束的相互影响，帧周期T设置成
Figure PCTCN2020141729-appb-000001
即当最大目标位于最大测量距离处时，脉冲串中的最后一个脉冲从被发射器21发射开始直到被采集器22接收到结束所需要的时间正好是t 1，这样就确保了在单帧周期内所有的脉冲串均会被接收且不会有相邻帧周期内的脉冲响应。通过配置发射具有时间编码的光信号脉冲串，有效提高了帧率，同时可以提升距离测量系统的抗干扰能力。并且，控制和处理电路13控制发射器21发射光信号脉冲串的时间相对计时信号存在错位时间R 1，而采集器在收到触发信号后开始采集反射光子，同步触发信号的计时信号控制TDC电路开始计时，记录光脉冲中的光子从发射到接收的 时间，这样确保反射的光脉冲中的光子均能被检测到。
在一些实施例中，预存储基于时间编码的滤波核，控制和处理电路13基于滤波核与直方图电路中绘制的直方图进行卷积计算互相关以确定脉冲峰值位置，并根据脉冲峰值位置确定飞行时间。
在一些实施例中，直方图电路根据发射光信号脉冲的时间编码方式，采用时间编码连续单光子计数叠加的方式绘制直方图，即以当前要绘制的直方图为起始单元，根据时间编码将时序串中相应时间单元的光子计数值进行叠加，叠加后的光子计数为起始时间单元的光子计数数值。例如，发射光信号脉冲串的时间编码为[Δt 1，Δt 1+Δt 2，Δt 1+Δt 2+Δt 3，…，Δt 1+Δt 2…+Δt (n-1)]时，以当前要绘制的时间单元为起始单元，将时序串后续中与该起始单元相隔Δt 1，Δt 1+Δt 2，Δt 1+Δt 2+Δt 3，…，Δt 1+Δt 2…+Δt (n-1)的所有时间单元的光子计数值与起始的光子计数值依次叠加，叠加后的光子计数作为直方图中该时间单元的数值。确定直方图中的脉冲峰值位置，并根据脉冲峰值位置确定飞行时间。
图3所示是本申请另一个实施例的错位发射时间编码脉冲调制示意图。如图3所示，发射器31发射具有双重随机(伪随机)时间编码的光信号脉冲串(所用时间编码技术可以参考中国专利申请公开第CN201910814076.0号中的相关内容)，所发射脉冲分成多个脉冲组，每个脉冲组内包含多个脉冲，脉冲组以第一随机时间编码[Δt 1，Δt 1+Δt 2，Δt 1+Δt 2+Δt 3，…，Δt 1+Δt 2…+Δt (n-1)]的形式发射，其中，Δt i表示第i个脉冲与第(i+1)个脉冲的时间间隔，i＝1，2，…(n-1)；组与组之间以第二随机时间编码[ΔT 1，ΔT 1+ΔT 2，ΔT 1+ΔT 2+ΔT 3，…，ΔT 1+ΔT 2…+ΔT (N-1)]的形式进行发射，ΔT j表示第j个脉冲组与第(j+1)个脉冲组的时间间隔，j＝1,2,…(N-1)，N代表脉冲组的数量。若被测目标在D处，对应的飞行时间是t，则在t时间后采集器32将相继接收到被目标反射的脉冲串中的光子，为了保证避免相邻两帧周期中脉冲光束的相互影响，帧周期T设置成
Figure PCTCN2020141729-appb-000002
Figure PCTCN2020141729-appb-000003
即当最大目标位于最大测量距离处时，脉冲串中的最后一个脉冲从被发射器31发射开始直到被采集器32接收到结束所需要的时间正好是t 1，这 样就确保了在单帧周期内所有的脉冲串均会被接收且不会有相邻帧周期内的脉冲响应。
与图2所示不同的是，控制和处理电路13控制发射器31在发射每组光脉冲时都具相对计时信号的错位时间，该错位时间也呈编码模式，即错位时间编码[R 1，R 1+R 2，R 1+R 2+R 3，…，R 1+R 2…+R N]，N代表脉冲组的数量，R k表示第k个脉冲组相对计时信号的错位时间，k＝1,2,…N，该错位时间是随机(伪随机)的，并且该错位时间R k服从高斯分布，高斯分布的标准差被配置为光脉冲的脉冲宽度的随机数。
在一些实施例中，预存储基于双重时间编码的滤波核，控制和处理电路13基于滤波核与直方图电路中绘制的直方图进行卷积计算互相关以确定脉冲峰值位置，并根据脉冲峰值位置确定飞行时间。
在一些实施例中，根据发射光信号脉冲的时间编码方式，采用时间编码叠加后再融合的方式绘制直方图。即分成两步进行绘制(两步无分先后)，第一步即为将N个脉冲组周期单光子计数时序串之间相应时间单元的光子计数进行叠加；第二步将第一步中所得到的的总时序串根据脉冲组内发射脉冲的第一时间编码进行叠加。确定直方图中的脉冲峰值位置，并根据脉冲峰值位置确定飞行时间
可以理解的是，配置发射器发射基于时间编码的光信号脉冲串，可以有效的提高距离测量系统的抗干扰能力，但在一些实施例中，发射器被配置为由多个光源组成的光源阵列，以同时发射多个光信号脉冲串，相邻光源发射的光脉冲被目标反射后被采集器接收时也会产生串扰现象，为解决系统自身引起的干扰问题，可设置每个光源均发射具有不同时间编码的光信号脉冲串。或者，在一些实施例中，配置光源发射具有双重时间编码的光信号脉冲串，其中脉冲组以相同的第一随机时间编码发射脉冲串，改变组与组之间具有不同的随机时间编码形式以实现每个光源发射具有不同时间编码的光信号脉冲串，也可以有效避免产生串扰的情况。同时，控制和处理电路控制发射器在接收到触发信号后 调控光脉冲的发射相对计时信号存在错位时间，可解决pile-up的问题。
参照图4所示，作为本申请另一实施例，本申请还提出了一种距离测量方法，图4为距离测量方法的流程图示，方法包括如下步骤：
S40、控制发射器发射具有时间编码的光信号脉冲串；
S41、控制采集器采集被物体反射回的光信号脉冲串中的光子；
S42、通过控制和处理电路产生计时信号调控TDC电路计时，记录光子的入射时间以形成帧周期单光子计数时序串；
其中，控制和处理电路控制光信号脉冲串的发射时间相对计时信号存在错位时间，并基于帧周期单光子计数时序串绘制直方图，以确定飞行时间。
在本申请实施例中，错位时间是随机的，且服从高斯分布，高斯分布的标准差被配置为光脉冲的脉冲宽度的随机数。
在一些实施例中，发射器发射具有双重随机或伪随机时间编码的光信号脉冲串，所发射脉冲分成多个脉冲组，每个脉冲组内包含多个脉冲，脉冲组以第一随机时间编码的形式发射；脉冲组之间以第二随机时间编码的形式进行发射；其中，控制和处理电路控制发射器在发射每组光脉冲时具有相对计时信号的错位时间，其中错位时间也呈编码模式，该错位时间是随机(伪随机)的，并且该错位时间服从高斯分布，高斯分布的标准差被配置为光脉冲的脉冲宽度的随机数。
在一些实施例中，还包括步骤：预存储基于时间编码的滤波核，控制和处理电路基于滤波核与绘制的直方图进行卷积计算互相关以确定脉冲峰值位置，并根据脉冲峰值位置确定飞行时间；
需要说明的是，本实施例的距离测量方法采用上述的距离测量系统进行距离测量，其技术方案与上述距离测量系统相同，故在此不再重复赘述。
可以理解的是，本申请在有效解决干扰问题的基础上进一步提出了解决pile-up现象的方案，提高了距离测量系统的准确性，同时增强了系统的抗干扰特性并有效的提高了帧率。
本申请实施还提供一种存储介质，用于存储计算机程序，该计算机程序被执行时至少执行前述实施例所述的距离测量方法。
所述存储介质可以由任何类型的易失性或非易失性存储设备、或者它们的组合来实现。其中，非易失性存储器可以是只读存储器(ROM，Read Only Memory)、可编程只读存储器(PROM，Programmable Read-Only Memory)、可擦除可编程只读存储器(EPROM，ErasableProgrammable Read-Only Memory)、电可擦除可编程只读存储器(EEPROM，ElectricallyErasable Programmable Read-Only Memory)、磁性随机存取存储器(FRAM，FerromagneticRandom Access Memory)、快闪存储器(Flash Memory)、磁表面存储器、光盘、或只读光盘(CD-ROM，Compact Disc Read-Only Memory)；磁表面存储器可以是磁盘存储器或磁带存储器。易失性存储器可以是随机存取存储器(RAM，Random Access Memory)，其用作外部高速缓存。通过示例性但不是限制性说明，许多形式的RAM可用，例如静态随机存取存储器(SRAM，Static Random Access Memory)、同步静态随机存取存储器(SSRAM，SynchronousStatic Random Access Memory)、动态随机存取存储器(DRAM，Dynamic Random AccessMemory)、同步动态随机存取存储器(SDRAM，Synchronous Dynamic Random AccessMemory)、双倍数据速率同步动态随机存取存储器(DDRSDRAM，Double Data RateSynchronous Dynamic Random Access Memory)、增强型同步动态随机存取存储器(ESDRAM，Enhanced Synchronous Dynamic Random Access Memory)、同步连接动态随机存取存储器(SLDRAM，SyncLink Dynamic Random Access Memory)、直接内存总线随机存取存储器(DRRAM，Direct Rambus Random Access Memory)。本申请实施例描述的存储介质旨在包括但不限于这些和任意其它适合类型的存储器。
本申请实施例还提供一种计算机设备，所述计算机设备包括存储器、处理器以及存储在所述存储器上并可在所述处理器上运行的计算机程序，其中，所述处理器执行所述计算机程序时至少实现前述实施例方案中所述的距离测量方法。
可以理解的是，以上内容是结合具体/优选的实施方式对本申请所作的进一步详细说明，不能认定本申请的具体实施只局限于这些说明。对于本申请所属技术领域的普通技术人员来说，在不脱离本申请构思的前提下，其还可以对这些已描述的实施方式做出若干替代或变型，而这些替代或变型方式都应当视为属于本申请的保护范围。在本说明书的描述中，参考术语“一种实施例”、“一些实施例”、“优选实施例”、“示例”、“具体示例”、或“一些示例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本申请的至少一个实施例或示例中。
在本说明书中，对上述术语的示意性表述不必须针对的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任一个或多个实施例或示例中以合适的方式结合。此外，在不相互矛盾的情况下，本领域的技术人员可以将本说明书中描述的不同实施例或示例以及不同实施例或示例的特征进行结合和组合。尽管已经详细描述了本申请的实施例及其优点，但应当理解，在不脱离由所附权利要求限定的范围的情况下，可以在本文中进行各种改变、替换和变更。
此外，本申请的范围不旨在限于说明书中所述的过程、机器、制造、物质组成、手段、方法和步骤的特定实施例。本领域普通技术人员将容易理解，可以利用执行与本文所述相应实施例基本相同功能或获得与本文所述实施例基本相同结果的目前存在的或稍后要开发的上述披露、过程、机器、制造、物质组成、手段、方法或步骤。因此，所附权利要求旨在将这些过程、机器、制造、物质组成、手段、方法或步骤包含在其范围内。

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  1. 一种距离测量系统，其特征在于，包括：
    发射器，经配置以发射具有时间编码的光信号脉冲串；
    采集器，经配置以采集被物体反射回的所述光信号脉冲串中的光子；
    控制和处理电路，与所述发射器以及所述采集器连接，同步所述发射器与所述采集器的触发信号，并产生与所述触发信号同步的计时信号调控TDC电路计时，记录所述光子的入射时间以形成帧周期单光子计数时序串；
    其中，所述控制和处理电路控制所述光信号脉冲串的发射时间相对所述计时信号存在错位时间，并基于所述帧周期单光子计数时序串绘制直方图，以确定飞行时间。
  2. 如权利要求1所述的距离测量系统，其特征在于：所述错位时间是随机的，且服从高斯分布，所述高斯分布的标准差被配置为所述光脉冲的脉冲宽度的随机数。
  3. 如权利要求1所述的距离测量系统，其特征在于：所述发射器被配置为由多个光源组成的光源阵列，所述光源阵列中的每个光源均发射具有不同时间编码的光信号脉冲串。
  4. 如权利要求1所述的距离测量系统，其特征在于：所述控制和处理电路基于预存储的基于所述时间编码的滤波核与绘制的所述直方图进行卷积计算互相关以确定脉冲峰值位置，并根据所述脉冲峰值位置确定飞行时间；或者，
    基于所述光信号脉冲串的所述时间编码方式，采用时间编码连续单光子计数叠加的方式绘制所述直方图，根据所述直方图中的脉冲峰值确定飞行时间。
  5. 如权利要求1所述的距离测量系统，其特征在于：所述发射器发射具有双重随机时间编码的光信号脉冲串，所述发射脉冲分成多个脉冲组，每个所述脉冲组内包含多个脉冲，所述脉冲组以第一随机时间编码的形式发射；所述脉冲组之间以第二随机时间编码的形式进行发射。
  6. 如权利要求5所述的距离测量系统，其特征在于：所述控制和处理电路 控制所述发射器在发射每组光脉冲时具有相对所述计时信号的所述错位时间，所述错位时间呈编码模式。
  7. 一种距离测量方法，其特征在于，包括如下步骤：
    S40、控制发射器发射具有时间编码的光信号脉冲串；
    S41、控制采集器采集被物体反射回的所述光信号脉冲串中的光子；
    S42、通过控制和处理电路产生计时信号调控TDC电路计时，记录所述光子的入射时间以形成帧周期单光子计数时序串；
    其中，所述控制和处理电路控制所述光信号脉冲串的发射时间相对所述计时信号存在错位时间，并基于所述帧周期单光子计数时序串绘制直方图，以确定飞行时间。
  8. 如权利要求7所述的距离测量方法，其特征在于：所述错位时间是随机的，且服从高斯分布，所述高斯分布的标准差被配置为所述光脉冲的脉冲宽度的随机数。
  9. 如权利要求7所述的距离测量方法，其特征在于：所述发射器发射具有双重随机时间编码的光信号脉冲串，所述发射脉冲分成多个脉冲组，每个所述脉冲组内包含多个脉冲，所述脉冲组以第一随机时间编码的形式发射；所述脉冲组之间以第二随机时间编码的形式进行发射。
  10. 如权利要求7所述的距离测量方法，其特征在于，还包括步骤：预存储基于所述时间编码的滤波核，所述控制和处理电路基于所述滤波核与绘制的所述直方图进行卷积计算互相关以确定脉冲峰值位置，并根据所述脉冲峰值位置确定飞行时间；或者，
    所述控制和处理电路基于所述光信号脉冲串的所述时间编码方式，采用时间编码连续单光子计数叠加的方式绘制所述直方图，根据所述直方图中的脉冲峰值确定飞行时间。
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