CN111487637B - Distance measurement system and method based on time delay - Google Patents
Distance measurement system and method based on time delay Download PDFInfo
- Publication number
- CN111487637B CN111487637B CN202010311685.7A CN202010311685A CN111487637B CN 111487637 B CN111487637 B CN 111487637B CN 202010311685 A CN202010311685 A CN 202010311685A CN 111487637 B CN111487637 B CN 111487637B
- Authority
- CN
- China
- Prior art keywords
- time
- delay
- pulse
- histogram
- pixel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000005259 measurement Methods 0.000 title claims abstract description 30
- 230000003111 delayed effect Effects 0.000 claims abstract description 72
- 238000012545 processing Methods 0.000 claims abstract description 66
- 230000008569 process Effects 0.000 claims abstract description 13
- 230000003287 optical effect Effects 0.000 claims description 17
- 230000001934 delay Effects 0.000 claims description 12
- 238000000691 measurement method Methods 0.000 claims description 10
- 238000001914 filtration Methods 0.000 description 16
- 230000001276 controlling effect Effects 0.000 description 10
- 238000010586 diagram Methods 0.000 description 10
- 238000011084 recovery Methods 0.000 description 7
- 230000001360 synchronised effect Effects 0.000 description 7
- 238000001514 detection method Methods 0.000 description 6
- 238000004364 calculation method Methods 0.000 description 4
- 230000006870 function Effects 0.000 description 4
- 230000001105 regulatory effect Effects 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 230000001788 irregular Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 230000003068 static effect Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000001208 nuclear magnetic resonance pulse sequence Methods 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 230000002123 temporal effect Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000004422 calculation algorithm Methods 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000004590 computer program Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- 238000001161 time-correlated single photon counting Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- 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
- G01S7/484—Transmitters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Electromagnetism (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
The invention discloses a distance measurement system based on time delay, which comprises: a transmitter, a collector, and control and processing circuitry; the emitter is used for emitting pulse light beams, and at least part of the pulse light beams are reflected by the target area to form reflected light beams; the collector receives at least part of pulse light beams in the reflected light beams, comprises a pixel unit composed of a plurality of pixels, collects photons in the light pulses through the pixels, and outputs photon signals indicating the collected photons; and the control and processing circuit performs delay processing on the photon signals to obtain delayed photon signals with time delay, obtains delay flight time, and processes the delay flight time according to the delay time of the delayed photon signals to obtain flight time corresponding to the light pulse collected by each pixel. The delay control circuit is used for applying time delay to the photon signals to obtain delay photon signals, so that the situation that the flight time cannot be accurately identified due to wave crest overlapping in the histogram can be avoided.
Description
Technical Field
The invention relates to the technical field of laser ranging, in particular to a distance measuring system and method based on time delay.
Background
The distance measurement can be performed on the target by utilizing the Time of Flight (Time) principle and the structured light principle to obtain a depth image containing the depth value of the target, and further based on the depth image, the functions of three-dimensional reconstruction, face recognition, human-computer interaction and the like can be realized, and the related distance measurement system is widely applied to the fields of consumer electronics, unmanned aerial vehicle driving, AR/VR and the like. The distance measuring system based on the time-of-flight principle generally comprises a transmitter and a collector, wherein the transmitter transmits a pulse beam to irradiate a target view field, the pulse beam irradiates the target view field and then is reflected by a target object, the collector collects reflected light beams reflected back, and the time required for the light beams to be transmitted to be received back is calculated to calculate the distance of the object; the structured light distance measurement system calculates the distance of the object by processing the reflected beam pattern and using trigonometry.
In a distance measurement system based on the time of flight principle, a single photon avalanche photodiode (SPAD) is a detector capable of capturing individual photons with very high time-of-arrival resolution on the order of tens of picoseconds. SPAD based detector arrays may be fabricated in dedicated semiconductor processes or in standard CMOS technology. In a direct time-of-flight measurement system using SPADs, a single photon incident to SPAD will cause an avalanche and pass the avalanche signal into a TDC circuit, the time of photon emission to avalanche is detected by the TDC circuit, and the time interval is subjected to histogram statistics through multiple detections to recover the waveform of the entire pulse signal. However, the circuit for processing the photon signal generated by the photon detection of the SPAD includes a large number of TDC and histogram circuits, which occupies a large chip area, and is not beneficial to miniaturization design, but if a plurality of pixels share one TDC and histogram circuit, the waveform of the characterization pulse signal generated after each pixel collects the light beam will have the situation that the peaks overlap after the statistics of the histogram circuit, so that a specific plurality of flight times and a specific pixel unit for which each flight time is generated by collecting the photon cannot be accurately identified.
The foregoing background is only for the purpose of providing an understanding of the inventive concepts and technical aspects of the present application and is not necessarily prior art to the present application and is not intended to be used as an aid in the evaluation of the novelty and creativity of the present application in the event that no clear evidence indicates that such is already disclosed at the date of filing of the present application.
Disclosure of Invention
The application aims to provide a distance measurement system and a distance measurement method based on time delay, which are used for solving at least one of the problems in the background technology.
In order to achieve the above object, the technical solution of the embodiment of the present application is as follows:
a time delay based distance measurement system comprising:
an emitter for emitting a pulsed light beam towards a target area; wherein at least part of the pulse light beam is reflected by the target area to form a reflected light beam;
a collector for receiving at least part of the pulse light beams in the reflected light beams, wherein the collector comprises a pixel unit composed of a plurality of pixels, photons in the light pulses are collected through the pixels, and photon signals indicating the collected photons are output;
the control and processing circuit is connected with the emitter and the collector to delay the photon signals generated by the photons received by the pixels to obtain delayed photon signals with time delay, the delayed photon signals of the pixels are collected through the TDC circuit to obtain photon counting strings, a histogram is drawn based on the photon counting strings, the delay flight time corresponding to each pixel is determined according to the histogram, and the delay flight time is processed according to the delay time of the delayed photon signals to obtain the flight time corresponding to the light pulses collected by each pixel.
In some embodiments, the transmitter is configured to transmit a time-coded optical pulse train towards a target area; wherein the time code is a single time code or multiple time codes.
In some embodiments, the emitter is configured as a light source array composed of a plurality of light sources, the light source array having a one-to-one correspondence with the pixel units.
In some embodiments, the control and processing circuitry controls the light sources corresponding to the respective pixels to emit coded pulse beams of different time codes, denoted coded pulse trains, respectively.
In some embodiments, the control and processing circuitry controls the emitters to sequentially emit light pulses having different encoding modes while controlling portions of the pixels to be on and other pixels to be off.
In some embodiments, the control and processing circuitry looks up in the histogram from the encoded pulse waveform to obtain a pulse waveform matching the encoded pulse waveform, and obtains the delay time of flight from the matching pulse waveform.
The other technical scheme of the embodiment of the invention is as follows:
a distance measurement method based on time delay comprises the following steps:
S1, controlling an emitter to emit a pulse light beam towards a target area, wherein at least part of the pulse light beam is reflected by the target area to form a reflected light beam;
s2, receiving at least part of pulse light beams in the reflected light beams through a collector, wherein the collector comprises a pixel unit consisting of a plurality of pixels, receiving photons in the light pulses through the pixels, and outputting photon signals indicating the collected photons;
step S3, a control and processing circuit carries out delay processing on photon signals generated by photons received by the pixels to obtain delayed photon signals with time delay, the delayed photon signals of a plurality of pixels are collected through a TDC circuit to obtain photon counting strings, a histogram is drawn based on the photon counting strings, and delay flight time corresponding to each pixel is determined according to the histogram;
and S4, performing time restoration according to the delay flight time and the delay time of the delay photon signal to obtain the flight time corresponding to the light pulse received by each pixel.
In some embodiments, the control and processing circuitry includes delay control circuitry, TDC circuitry, and histogram circuitry; the delay control circuit is connected with pixels in the pixel units to process photon signals generated by photons received by the pixels, so as to obtain delayed photon signals with time delay; the TDC circuitry is configured to collect the delayed photon signals of a plurality of pixels to obtain the photon counting string; the histogram circuit is used for drawing the histogram according to the photon counting string.
In some embodiments, the emitter is configured as a light source array composed of a plurality of light sources, the light source array having a one-to-one correspondence with the pixel units; the control and processing circuit respectively controls each light source corresponding to each pixel to emit coded pulse light beams with different codes, each pixel receives different coded light pulses, corresponding matching waveforms are searched in the histogram according to each coded pulse waveform, and the delay flight time is determined according to the waveforms.
In some embodiments, the control and processing circuitry controls the emitters to sequentially emit light pulses having different encoding modes while controlling portions of the pixels to be on and other pixels to be off.
The technical scheme of the invention has the beneficial effects that:
according to the distance measurement system based on time delay, the time delay is applied to the photon signals through the delay control circuit to obtain the delayed photon signals, a plurality of misaligned pulse waveforms can be obtained in the histogram through the delayed photon signals, a plurality of delay flight times are obtained according to the pulse waveforms, and further time recovery is carried out according to the delay time set by the delay control circuit to obtain the accurate flight time corresponding to each target point, so that the situation that the flight time cannot be accurately identified due to the fact that peaks overlap in the histogram can be avoided.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.
FIG. 1 is a schematic diagram of a time delay based distance measurement system according to one embodiment of the invention.
Fig. 2 is a schematic diagram of the control and processing circuitry of the time delay based distance measurement system of the embodiment of fig. 1.
FIG. 3 is a schematic diagram of a histogram formed by the time delay of the time delay based distance measurement system of FIG. 1.
Fig. 4 is a flow chart of a distance measurement method based on time delay according to one embodiment of the invention.
Fig. 5 is a schematic diagram of a control and processing circuit of a time delay based distance measurement system according to another embodiment of the invention.
FIG. 6 is a schematic diagram of a histogram formed by the time delay of the time delay based distance measurement system of FIG. 5.
Fig. 7 is a flowchart of a distance measurement method based on time delay according to another embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved by the embodiments of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and the embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. In addition, the connection may be for a fixing function or for a circuit communication function.
It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing embodiments of the invention and to simplify the description by referring to the figures, rather than to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the invention.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless explicitly defined otherwise.
Fig. 1 is a schematic diagram of a distance measuring system according to an embodiment of the present invention, the distance measuring system 10 comprising a transmitter 11, a collector 12 and a control and processing circuit 13. Wherein the emitter 11 is configured to emit a light beam 30 toward the target area 20, the light beam 30 is emitted into the target area space to illuminate a target object in the space, at least a portion of the emitted light beam 30 is reflected by the target area 20 to form a reflected light beam 40, and at least a portion of the reflected light beam 40 is received by the collector 12; the control and processing circuit 13 is connected to the emitter 11 and the collector 12, respectively, and synchronizes the trigger signals of the emitter 11 and the collector 12 to calculate the time required for the light beam to be received from emission to reflection, that is, the time of flight t between the emitted light beam 30 and the reflected light beam 40, further, according to the time of flight t, the distance D of the corresponding point on the target object can be calculated by the following formula:
D＝c·t/2 (1)
Wherein c is the speed of light.
The emitter 11 includes a light source 111, an emitting 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), or the like, or may be a one-or two-dimensional light source array composed of a plurality of light sources. Preferably, the light source array is a VCSEL array light source chip formed by generating a plurality of 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 a light beam outwards under the control of the driver 113. In one embodiment, the light source 111 emits a pulsed light beam outwards at a frequency (pulse period) under control of the driver 113 for use in Direct time of flight (Direct TOF) measurements, wherein the frequency may be set according to the measured distance. It will be appreciated that a portion of the control and processing circuitry 13 or sub-circuitry present independently of the control and processing circuitry 13 may also be used to control the light source 111 to emit a light beam.
The emission optical element 112 receives the light beam emitted from the light source 111 and projects the shaped light beam onto a target area. In one embodiment, the transmitting optical element 112 receives the pulsed light beam from the light source 111 and optically modulates the pulsed light beam, such as diffracting, refracting, reflecting, etc., and then transmits the modulated light beam, such as a focused light beam, a flood light beam, a structured light beam, etc., into space. The emission optical element 112 may be a combination of one or more of a lens, a liquid crystal element, a diffractive optical element, a microlens array, a Metasurface (Metasurface) optical element, a mask, a mirror, a MEMS galvanometer, and the like.
The collector 12 includes a pixel unit 121, a filter unit 122, and a receiving optical element 123; wherein the receiving optical element 123 is configured to receive at least part of the light beam reflected by the target and guide the light beam onto the pixel unit 121; the filtering unit 122 is used for filtering out background light or stray light. Pixel cell 121 comprises a two-dimensional array of pixels, in one embodiment, pixel cell 121 may be a pixel array of single photon avalanche photodiodes (SPADs) that can respond to an incident single photon and output a signal indicative of the arrival time of the received photon at each SPAD, with the collection of weak optical signals and calculation of time of flight being accomplished using, for example, time-dependent single photon counting (TCSPC).
The control and processing circuit 13 synchronizes the trigger signals of the emitter 11 and the collector 12, processes the photon signals of the light beams collected by the pixel units, and calculates the distance information of the object to be measured based on the flight time from the emission to the reflection of the light beams back to the received light beams. In one embodiment, the SPAD outputs a photon signal in response to an incident single photon, and the control and processing circuitry 13 receives the photon signal and performs signal processing to obtain the time of flight of the beam.
In particular, the control and processing circuit 13 calculates the number of collected photons to form successive time bins which are linked together to form a statistical histogram to reproduce the time sequence of reflected light pulses, the time of flight of the pulsed light beam from emission to reception being identified by peak matching and filtering detection. In some embodiments, the control and processing circuitry 13 includes signal amplifiers, time-to-digital converters (TDCs), digital-to-analog converters (ADCs), and the like. It will be appreciated that the control and processing circuitry 13 may be a separate dedicated circuit, such as a dedicated SOC chip, FPGA chip, ASIC chip, etc., or may comprise general purpose processing circuitry.
In some embodiments, the distance measurement system 10 further includes a memory for storing a pulse code program that is used to control the firing time, firing frequency, etc. of the light beam emitted by the light source 111.
Fig. 2 is a schematic diagram of the control and processing circuitry of a time delay based distance measurement system according to one embodiment of the invention. In the embodiment of the present invention, the control and processing circuit 22 includes a delay control circuit 221, a TDC circuit 222, and a histogram circuit 223. Wherein the delay control circuit 221 is connected to the pixels in the pixel unit 121 to process the photon signals generated by the photons received by the pixels, and obtain delayed photon signals with time delay; the TDC circuitry 222 is configured to acquire delayed photon signals of a plurality of pixels to obtain a photon count string; the histogram circuit 223 draws a histogram from the photon count string; wherein a plurality of pulse waveforms appear in the histogram, the control and processing circuit 22 determines the time corresponding to the pulse waveforms in the histogram by using methods such as peak matching and filtering detection, determines the delay flight time corresponding to each pixel based on the time corresponding to the pulse waveforms, performs time restoration according to the delay flight time of each pixel and the delay time of the delay photon signal, and determines the flight time corresponding to the light pulse collected by each pixel.
Fig. 3 shows a histogram formed by a time delay of a time delay based distance measurement system according to an embodiment of the present invention, and in combination with fig. 2, it is assumed that a TDC circuit and a histogram circuit are shared by every four pixels in the embodiment of the present invention. As shown in fig. 2, the first pixel 211, the second pixel 212, the third pixel 213, and the fourth pixel 214 respectively collect distance information of four closely spaced target points D1, D2, D3, and D4 in the target area, and the calculated time of flight t1, t2, t3, and t4 after each corresponding pixel receives the reflected photon will be very close.
To distinguish the corresponding flight time of each pixel, a time delay is applied to the photon signal by the delay control circuit 221 to obtain a delayed photon signal, a plurality of misaligned pulse waveforms can be obtained in the histogram by the delayed photon signal, and a plurality of delayed flight times are obtained according to the pulse waveforms; and the corresponding relation between the delay flight time and the pixels is determined by controlling the time delay, and the time recovery is further carried out according to the delay time set by the delay control circuit, so that the accurate flight time corresponding to each target point is obtained.
As shown in fig. 2, the first pixel 211 is connected to a first delay control circuit 221, and the first photon signal passes through a first delay time Δt 1 After forming a first delayed photon signal, the first delayed photon signal is input to the TDC circuit 222, the TDC circuit 222 records the incident time of the photon according to the first delayed photon signal, and the first delayed flight time, i.e. t, is obtained by filtering after drawing a histogram in the histogram circuit 223 1 +Δt 1 The method comprises the steps of carrying out a first treatment on the surface of the The second pixel 212 is connected to the second delay control circuit 231, and the second photon signal is delayed by a second delay time Δt 2 A second delayed photon signal is formed, and a second delayed flight time, i.e. t, is obtained by filtering after drawing a histogram in the histogram circuit 223 2 +Δt 2 The method comprises the steps of carrying out a first treatment on the surface of the Similarly, the photon signal output by the third pixel 213 passes through the third delay control circuit 241 to obtain a third delay time of flight, i.e. t, in the histogram circuit 223 3 +Δt 3 The method comprises the steps of carrying out a first treatment on the surface of the The photon signal output by the fourth pixel 213 passes through the fourth delay control circuit 251 and then obtains a fourth delay time of flight, i.e. t, in the histogram circuit 223 4 +Δt 4 。
By a delay time Deltat 1 ，Δt 2 ，Δt 3 ，Δt 4 The control is carried out to ensure that the delay time is different and gradually increases, thereby achieving the purposes of controlling the signals generated by four pixels to collect photons to correspond to the waveforms obtained in the histogram without overlapping phenomenon, and being capable of being pressed as follows Arranged in the desired order, as shown in FIG. 3, i.e., t 1 +Δt 1 ＜t 2 +Δt 2 ＜t 3 +Δt 3 ＜t 4 +Δt 4 . The control and processing circuit 22 performs time repair based on the delay time corresponding to each delay time of flight to obtain an accurate time of flight t 1 、t 2 、t 3 、t 4 。
It will be appreciated that the difference of the four delay times may be controlled so that the difference is large to ensure that the four peaks formed in the histogram do not coincide, and that by controlling the difference of the delay times of adjacent pixels, the first peaks in the pulse waveform formed by the light pulses collected by each pixel in the histogram are arranged in sequence, so that the time of flight can be determined by determining the position of the first peak in the pulse waveform. However, if Δt 4 When the setting is too large, the storage time bin of the corresponding histogram circuit can be correspondingly increased, so that the calculation amount of the histogram circuit is increased, the occupied chip area is correspondingly increased, and the miniaturization is not facilitated. Therefore, in practical applications, a specific delay time needs to be designed according to specific situations. It should be understood that the number in this embodiment is only specifically described, and should not be taken as limiting the invention.
In some embodiments, the transmitter 11 may be configured to transmit a time-coded optical pulse train towards the target area, wherein the time coding may be regular or irregular, may be a single time coding or a multiple time coding. For example, in one embodiment, the light source is positioned at a predetermined distance less than the maximum detection range D max Corresponding time of flight t=2d max The pulse interval deltat of/c is transmitted for n pulses to form a pulse train, and the frame period T is set to be T (n-1) x deltat+t in order to ensure that the mutual influence of the light pulses in two adjacent frame periods is avoided. Correspondingly, the collector 21 is activated to collect a portion of photons reflected back by the target, forming a counting timing string with the time the TDC circuit collects the incident photons, the control and processing circuit 22 drawing a histogram based on the timing string in the histogram circuit 223.
The followingTaking the first pixel 211 and the second pixel 212 as examples, it is assumed that the first pulse in the pulse train is transmitted to the target D1 and is collected by the first pixel 211 after the flight time t1, and is delayed by Δt by the first delay control circuit 1 After that, the TDC circuit 222 records the photon incidence time according to the first delayed photon signal, draws a histogram in the histogram circuit 223, and obtains the first delayed flight time through filtering; similarly, the first pulse is transmitted to the target D2 and is collected by the second pixel 212 after the flight time t2, and is delayed by Δt by the second delay control circuit 2 After that, the TDC circuit 222 records the time of photon incidence from the second delayed photon signal, draws a histogram in the histogram circuit 223, and obtains the second delayed flight time through filtering processing. In one embodiment, after n pulse periods Δt, the histogram is drawn in the histogram circuit, and then a higher value is obtained on a plurality of time units, so as to form a waveform diagram reflecting the pulse shape, and two groups of pulse waveforms are obtained after filtering processing, wherein each group of pulse waveforms corresponds to the first pixel and the second pixel respectively. Determining the position of a wave crest in the pulse waveform, and calculating to obtain flight time t corresponding to the first pixel and the second pixel respectively 1 +Δt 1 、t 2 +Δt 2 And restoring the flight time according to the delay time of the delay control circuit. In some embodiments, Δt is controlled by the delay control circuit 221 1 ＜Δt 2 To distinguish between time of flight t1 and t2, Δt can be set, for example 2 Is delta t 1 Is a multiple of (2). In one embodiment, for example, [ delta ] t can be controlled 1 ＜(n-1)Δt]＜Δt 2 The TDC circuit is used for collecting photon counting of the first pixel and then collecting photon counting of the second pixel after the photon counting of the first pixel is finished, and two groups of pulse waveforms drawn in the histogram circuit are not overlapped. To reduce the amount of computation and memory required in histogram rendering, the size of the smallest time unit of the histogram is adjusted to be an integer multiple of each time unit in the frame period single photon count timing string. It will be appreciated that the delay time may be arbitrarily set depending on the particular system parameters. By configuring the light source to emit a time-coded pulsed light beam, the pulsed light beam can be provided withThe frame rate and the accuracy of distance measurement are effectively improved.
In some embodiments, the emitter 11 is configured as a light source array composed of a plurality of light sources having a one-to-one correspondence with the pixel units, preferably, the light sources are VCSEL array light source chips formed by generating a plurality of VCSEL light sources on a monolithic semiconductor substrate. Continuing with the description below taking the first pixel 211 and the second pixel 212 as examples, the control and processing circuit 22 controls the first light source corresponding to the first pixel 211 and the second light source corresponding to the second pixel 212 to emit coded pulse beams of different time codes, respectively, as a first coded pulse train and a second coded pulse train. Wherein the first encoding pulse train is collected by the first pixel 211 after the time t1 passes after the target D1 is irradiated to output a first photon signal indicating the collected photons, and the first photon signal is output with a first delay time Δt after passing through the first delay control circuit 1 Is a first delayed photon signal of (a); the second encoded pulse train is collected by the second pixel 212 after an elapsed time t2 after being irradiated to the target D2 to output a second photon signal indicative of the collected photon, and the second photon signal is output after being passed through the second delay control circuit with a second delay time Deltat 2 Is included in the first delayed photon signal. The TDC circuit receives the first delay photon signal and the second delay photon signal and records the time of collecting the incident photons to form a time sequence string, and the histogram circuit draws a histogram based on the time sequence string. After counting, the obtained histogram can be seen to have higher values in a plurality of time units, a waveform diagram of the pulse shape of the reaction part is formed, and after filtering processing, the histogram is searched according to the first coding pulse waveform and the second coding pulse waveform to find a group of pulse waveforms matched with the first coding pulse waveform and a group of pulse waveforms matched with the second coding pulse waveform. For example, the first code pulse waveform and the waveform in the histogram can be subjected to convolution calculation cross-correlation by the filter kernel to find the corresponding matched waveform, the first delay flight time is obtained by determining the peak position by using the first pulse waveform in the matched waveform group, and the time recovery is performed according to the first delay time correspondingly set by the first pixel A first time of flight. By setting each pixel to receive different coded light pulses, only a smaller delay time is required to distinguish corresponding pulse waveforms in the histogram, the formed pulse waveforms are not required to be regulated and controlled to be arranged in a certain sequence, the corresponding waveforms formed by each pixel to receive the coded pulses are calculated through a correlation matching algorithm, the delay flight time is determined according to the waveforms, and the first flight time is determined by time restoration based on the delay time.
In some embodiments, the emitter 11 may be a light source or an array of light sources for emitting a flood beam towards the target area. The control and processing circuit 22 controls the emitter to emit light pulses of different temporal coding modes in sequence, while controlling part of the pixels to be on and the other pixels to be in an off state. For example, when the transmitter is controlled to emit a light pulse train with a first coding mode, the first pixel 211 is turned on, the other pixels are turned off, and the first pixel 211 receives the first coded light pulse train reflected from the target D1 and delays the first coded light pulse train by a first delay control circuit by Δt 1 And outputting a first delay photon signal, wherein the TDC circuit receives the photon signal record to obtain a frame period single photon counting string, and the histogram circuit draws a first histogram according to the counting string. The control and processing circuit 22 controls the transmitter to emit light pulses having a second encoding mode to turn on the second pixel 212 and turn off the other pixels, the second pixel 212 receiving the second encoded light pulses reflected from the target D2 for a delay Δt by the second delay control circuit 2 And outputting a second delayed photon signal, wherein the TDC circuit receives the photon signal record to obtain a frame period single photon counting string, and the histogram circuit draws a second histogram on the basis of the first histogram according to the counting string. Similarly, the delay flight time is determined according to the histogram, and further time reduction is performed to determine the first flight time, and the specific implementation method is the same as the foregoing method, and will not be described herein again.
As another embodiment of the present invention, there is also provided a distance measurement method based on time delay, referring to fig. 4, the method includes the steps of:
s1, controlling an emitter to emit a pulse beam towards a target area, wherein at least part of the pulse beam is reflected by the target area to form a reflected beam;
specifically, the emitter comprises a light source, an emitting optical element, and a driver; the light source is controlled by the driver to emit a pulsed light beam outwards at a frequency (pulse period). In some embodiments, the transmitter may be configured to transmit a time-coded optical pulse train towards the target area, wherein the time coding may be regular or irregular, may be a single time coding or a multiple time coding.
S2, receiving at least part of pulse light beams in the reflected light beams through a collector, and outputting photon signals indicating collected photons;
specifically, the collector includes a pixel unit including a pixel array composed of a plurality of pixels, and photons in the pulse beam are collected by the pixels, and a photon signal indicating the collected photons is output. In one embodiment, the pixel cell is a pixel array comprised of single photon avalanche photodiodes (SPADs) that are responsive to an incident single photon and output signals indicative of the arrival time of the received photon response at each SPAD.
Step S3, the control and processing circuit carries out delay processing on photon signals generated by received photons of pixels to obtain delayed photon signals with time delay, the delayed photon signals of a plurality of pixels are collected through the TDC circuit to obtain photon counting strings, a histogram is drawn based on the photon counting strings, time corresponding to pulse waveforms in the histogram is determined according to the histogram, and delay flight time corresponding to each pixel is determined based on the time corresponding to the pulse waveforms;
specifically, the control and processing circuit comprises a delay control circuit, a TDC circuit and a histogram circuit; the delay control circuit is connected with pixels in the pixel unit to process photon signals generated by photons received by the pixels, and delay photon signals with time delay are obtained; the TDC circuitry is configured to collect delayed photon signals of a plurality of pixels to obtain a photon counting string; the histogram circuit draws a histogram according to the photon counting string; wherein a plurality of pulse waveforms appear in the histogram, the control and processing circuit determines the time corresponding to the pulse waveforms in the histogram by using methods such as peak matching and filtering detection, and determines the delay flight time corresponding to each pixel based on the time corresponding to the pulse waveforms.
And S4, performing time restoration according to the delay flight time and the delay time of the delay photon signal to obtain the flight time corresponding to the light pulse acquired by each pixel.
In some embodiments, the emitter is configured as a light source array composed of a plurality of light sources, the light source array having a one-to-one correspondence with the pixel units; the control and processing circuit respectively controls each light source corresponding to each pixel to emit coded pulse light beams with different codes, each pixel receives different coded light pulses, a corresponding matching waveform is found in the histogram according to each coded pulse waveform, delay flight time is determined according to the waveform, and time recovery is performed based on the delay time to determine the flight time.
In some embodiments, the control and processing circuitry controls the emitter to sequentially emit light pulses having different temporal coding modes while controlling portions of the pixels to be on and other pixels to be in an off state. For example, when the transmitter is controlled to transmit the first coded light pulse train, the first pixel is turned on and the other pixels are in the off state, and the first pixel receives the first coded light pulse train reflected from the target D1 and delays the first coded light pulse train by a delay of Δt by the first delay control circuit 1 And outputting a first delay photon signal, wherein the TDC circuit receives the photon signal record to obtain a frame period single photon counting string, and the histogram circuit draws a first histogram according to the counting string. The control and processing circuit controls the transmitter to transmit a second coded light pulse train, turns on a second pixel, turns off other pixels, and the second pixel receives the second coded light pulse train reflected from the target D2 and delays the second coded light pulse train by deltat through a second delay control circuit 2 And outputting a second delayed photon signal, wherein the TDC circuit receives the delayed photon signal and records to obtain a frame period single photon counting string, and the histogram circuit draws a second histogram on the basis of the first histogram according to the counting string. Similarly, the delay flight time is determined according to the histogram, and further time reduction is performed to determine the flight time, and the detailed method is the same as that described in the foregoing scheme, so that the description is omitted.
Fig. 5 is a schematic diagram of a control and processing circuit of a distance measurement system based on a time delay according to yet another embodiment of the present invention. The control and processing circuit 42 includes a delay control circuit, a TDC circuit 422, and a histogram circuit 423. The transmitter 11 is configured to transmit a pulse beam, and reflect from a target area and then receive the pulse beam by a collector, where the collector includes a pixel unit 41, and in this embodiment, a TDC circuit 422 and a histogram circuit 423 are used for every two pixels in the pixel unit 41. The delay control circuit is connected with pixels (411, 412) in the pixel unit 41, and processes the first photon signal generated by the received photons of each pixel to obtain delayed photon signals with different time delays; the TDC circuit 422 is configured to acquire delayed photon signals of a plurality of pixels to obtain a photon count string; the histogram circuit 423 draws a histogram from the photon count string.
Specifically, pulse waveforms based on a time coding mode are stored in the control and processing circuit 42 in advance, the control and processing circuit 42 performs different time coding regulation on each delayed photon signal to obtain different delayed photon signal strings, when matching calculation is performed, the cross correlation can be calculated by using filtering processing to convolve the pulse waveforms of the time coding mode and waveforms in the histogram to determine corresponding matching waveforms in the histogram, the peak position determination is performed by using the first pulse waveform in the group of matching waveforms to obtain the delay flight time corresponding to each pixel, and the delay flight time is restored according to the delay time correspondingly set by the pixel to obtain the flight time of each pixel acquisition light pulse. The time codes are time intervals between the delay photon signal strings, the time intervals can be periodically changed or randomly changed, and the time intervals between the delay photon signal strings corresponding to each pixel in the periodic change are different.
In one embodiment, the delay control circuit includes a plurality of sub-delay control circuits, the first pixel 411 outputs a first photon signal after collecting photons, and the first photon signal is input into the first delay control circuit 421 and outputs a plurality of first delayed photon signals by applying different delay times to different sub-delay control circuits 4210, so as to form a delayed photon signal string with a first coding mode, namely a first delayed photon signal string; similarly, the second pixel 412 outputs a second photon signal after collecting photons, and the second photon signal is input to the second delay control circuit 424 to output a plurality of second delayed photon signals with different delay times, so as to form a delayed photon signal string with a second coding mode, i.e. a second delayed photon signal string. The photon signal string regulated by time coding is sampled and recorded in the TDC circuit 422 to form a single photon counting string, and a histogram circuit 423 is used for drawing a histogram to form a corresponding coding waveform.
Fig. 6 is a histogram formed after a time delay of the time delay based distance measurement system of the embodiment of fig. 5. The control and processing circuit 42 performs different time-coded modulation on each delayed photon signal to obtain a second, different delayed photon signal train, records the time of incidence of the corresponding photon by the TDC circuit to form a frame-period single photon count time series, and draws a histogram in the histogram circuit based on the time series.
In some embodiments, the pulse beam is emitted to the target D1 in one frame period, and the first pixel 411 collects and outputs a first photon signal after the time of flight t1, and the first photon signal outputs a plurality of first delayed photon signals after being delayed by a plurality of sub-delay control circuits in the first delay control circuit 421. In one embodiment, the delay of each sub-delay control circuit is periodically varied, such as by a first sub-delay control circuit delay Δt through a first delay control circuit 421 1 Post-input to TDC circuit 422; the second sub-delay control circuit through the first delay control circuit 421 delays by 2Δt 1 Post-input TDC circuit 422; the third sub-delay control circuit through the first delay control circuit 421 delays by 3 Δt 1 The post-input TDC circuit 422. Similarly, the pulsed light beam is emitted to the target D2, and after the time of flight t2, the second pixel 412 collects the second photon signal to form a second photon signal, where the second photon signal is delayed by a plurality of sub-delay control circuits in the second delay control circuit 422 to output a plurality of second delayed photon signals, for example: after passing through the first sub-delay control circuit of the second delay control circuit 422 Δt 2 Input to the TDC circuit 422; the second sub-delay control circuit via the second delay control circuit 422 delays by 2 Δt 2 Input to the TDC circuit 422; the third sub-delay control circuit via the second delay control circuit 422 delays by 3 Δt 2 The TDC circuit 422 is input.
It will be appreciated that a photon signal input to the TDC circuit will have a count value of "1" in the corresponding time unit; similarly, the delayed photon signal encoded by the delay control circuit can be regarded as a pixel collecting an optical pulse train containing n pulses; wherein the pulse period of the laser pulse train collected by the first pixel is delta t 1 The pulse period of the laser pulse string collected by the second pixel is delta t 2 Setting Δt 1 ＜Δt 2 To distinguish between the photon signal corresponding to the first pixel and the photon signal corresponding to the second pixel. In the embodiment of the invention, assuming that n is 3, a histogram is drawn in a histogram circuit, and two groups of pulse waveforms are formed in the histogram. The control and processing circuit 42 performs a filtering process on the waveforms in the histogram and the pulse sequence formed based on the encoding mode of the delay control circuit stored in advance. It can be understood that different encoding modes correspond to different filtering kernels, a first group of pulse waveforms corresponding to a first encoding mode and a second group of pulse waveforms corresponding to a second encoding mode are distinguished, the peak position of the first pulse waveform in the pulse waveforms is determined so as to obtain the delay flight time of each pixel, and time recovery is performed according to the delay time corresponding to each pixel to obtain the flight time.
In one embodiment, 3 Δt is set 1 ＜Δt 2 The first group of pulse waveforms formed by the encoded photon signals corresponding to the first pixels and the second group of pulse waveforms formed by the encoded photon signals corresponding to the second pixels are controlled to be sequentially arranged in the histogram, and no overlapping condition occurs.
In one embodiment, the delay time coding modes in the first delay control circuit and the second delay control circuit may be set to be different, for example, the delay time in each delay control circuit is randomly coded, after the TDC circuit records the time of the incident photon, a histogram is drawn in the histogram circuit, pulse waveforms corresponding to different pixels are distinguished through filtering processing, the delay flight time is determined by using the peak position, and the flight time is obtained after time recovery is performed according to the delay flight time.
In some embodiments, the distance measurement system may further include a time coding circuit, where the first photon signal output by each pixel passes through the delay control circuit to output delayed photon signals with different delay times, and each delayed photon signal is regulated by the time coding circuit to generate a plurality of delayed photon signals with time intervals, that is, form a delayed photon signal string with a time coding mode. The time interval can be periodically changed or randomly changed, and the histogram is drawn in the histogram circuit after the time of the incident photon is recorded by the TDC circuit. The control and processing circuit processes and distinguishes the pulse corresponding to each pixel according to the time coding mode and the pulse waveform in the histogram, and then determines the delay flight time by utilizing the peak position, and obtains the flight time after time recovery of the delay flight time.
In some embodiments, the time encoding circuit may be disposed in the delay control circuit, or may be disposed in the TDC circuit or the histogram circuit, and the logic implemented in the embodiments is different, but the first photon signal generated by each pixel may be finally processed in a series of processes to form a set of pulse waveforms with time encoding in the histogram, and the pulse waveforms corresponding to each pixel are distinguished by matching the time encoding mode with the waveforms, so as to determine the flight time of the light pulse collected by each pixel.
As another embodiment of the present invention, there is also provided a distance measurement method based on time delay, referring to fig. 7, the method includes the steps of:
step S20, controlling the emitter to emit a pulse beam towards a target area, wherein at least part of the pulse beam is reflected by the target area to form a reflected beam;
specifically, the emitter comprises a light source, an emitting optical element, and a driver; the light source is controlled by the driver to emit a pulsed light beam outwards at a frequency (pulse period).
S21, receiving at least part of pulse light beams in the reflected light beams through a collector, and outputting photon signals indicating collected photons;
specifically, the collector includes a pixel unit including a pixel array composed of a plurality of pixels, and photons in the pulse beam are collected by the pixels, and a photon signal indicating the collected photons is output. In one embodiment, the pixel cell is a pixel array comprised of single photon avalanche photodiodes (SPADs) that are responsive to an incident single photon and output signals indicative of the arrival time of the received photon response at each SPAD.
Step S22, the control and processing circuit delays photon signals generated by the received photons of the pixels to obtain delayed photon signals with time delay, and different time coding regulation and control are carried out on each delayed photon signal to obtain different delayed photon signal strings; collecting delay photon signal strings of a plurality of pixels through a TDC circuit to obtain photon counting strings, and drawing a histogram based on the photon counting strings;
specifically, the control and processing circuit comprises a delay control circuit, a TDC circuit and a histogram circuit; the delay control circuit comprises a plurality of sub-delay control circuits, photon signals output after the pixels collect photons are applied with different delay times by the different sub-delay control circuits, and then a plurality of delay photon signals are output, so that a delay photon signal string with a time coding mode is formed. The photon signal string regulated and controlled by time coding is sampled and recorded in a TDC circuit to form a single photon counting string, and a histogram circuit is used for drawing a histogram to form a corresponding coding waveform.
Step S23, pre-storing pulse waveforms based on a time coding mode in a control and processing circuit, searching in a histogram according to the pulse waveforms of the time coding mode, determining that the pulse waveforms in the histogram are associated with the stored pulse waveforms based on the time coding mode, determining delay flight time corresponding to each pixel, performing time restoration according to the delay flight time and the delay time, and determining the flight time of the light pulse collected by each pixel.
Specifically, the control and processing circuit performs filtering processing according to a pulse sequence formed by a time coding mode based on the delay control circuit and waveforms in the histogram. The time code is a time interval between the delay photon signal strings, the time interval can be periodically changed or randomly changed, and the time interval between the delay photon signal strings corresponding to each pixel in the periodic change is different.
In some embodiments, the time-encoding circuit may be configured to output a delayed photon signal having a different delay time after the photon signal output by each pixel passes through the delay control circuit, and each delayed photon signal is modulated by the time-encoding circuit to generate a plurality of delayed photon signals having time intervals, so as to form a delayed photon signal string having a time pattern.
The embodiments of the present application also provide a storage medium storing a computer program which, when executed, performs at least the method as described above.
The storage medium may be implemented by any type of volatile or non-volatile storage device, or combination thereof. The nonvolatile Memory may be a Read Only Memory (ROM), a programmable Read Only Memory (PROM, programmable Read-Only Memory), an erasable programmable Read Only Memory (EPROM, erasableProgrammable Read-Only Memory), an electrically erasable programmable Read Only Memory (EEPROM, electricallyErasable Programmable Read-Only Memory), a magnetic random Access Memory (FRAM, ferromagneticRandom Access Memory), a Flash Memory (Flash Memory), a magnetic surface Memory, an optical disk, or a compact disk Read Only (CD-ROM, compact Disc Read-Only Memory); the magnetic surface memory may be a disk memory or a tape memory. The volatile memory may be random access memory (RAM, random Access Memory), which acts as external cache memory. By way of example, and not limitation, many forms of RAM are available, such as static random access memory (SRAM, static Random Access Memory), synchronous static random access memory (SSRAM, synchronousStatic Random Access Memory), dynamic random access memory (DRAM, dynamic Random AccessMemory), synchronous dynamic random access memory (SDRAM, synchronous Dynamic Random AccessMemory), double data rate synchronous dynamic random access memory (ddr SDRAM, double Data RateSynchronous Dynamic Random Access Memory), enhanced synchronous dynamic random access memory (ESDRAM, enhanced Synchronous Dynamic Random Access Memory), synchronous link dynamic random access memory (SLDRAM, syncLink Dynamic Random Access Memory), direct memory bus random access memory (DRRAM, direct Rambus Random Access Memory). The storage media described in embodiments of the present application are intended to comprise, without being limited to, these and any other suitable types of memory.
It is to be understood that the foregoing is a further detailed description of the invention in connection with specific/preferred embodiments, and that the invention is not to be considered as limited to such description. It will be apparent to those skilled in the art that several alternatives or modifications can be made to the described embodiments without departing from the spirit of the invention, and these alternatives or modifications should be considered to be within the scope of the invention. In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention.
In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction. Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope as defined by the appended claims.
Furthermore, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. Those of ordinary skill in the art will readily appreciate that the above-described disclosures, procedures, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
Claims (10)
1. A time delay based distance measurement system comprising:
an emitter for emitting a pulsed light beam towards a target area; wherein at least part of the pulse light beam is reflected by the target area to form a reflected light beam;
a collector for receiving at least part of the pulse light beams in the reflected light beams, wherein the collector comprises a pixel unit composed of a plurality of pixels, photons in the light pulses are collected through the pixels, and photon signals indicating the collected photons are output;
the control and processing circuit is connected with the emitter and the collector to delay the photon signals generated by receiving photons by each pixel to obtain delayed photon signals with different time delays, the delayed photon signals of a plurality of pixels are collected through the TDC circuit to obtain photon counting strings, a histogram is drawn based on the photon counting strings, a plurality of misaligned pulse waveforms are obtained in the histogram, the delay flight time corresponding to each pixel is determined according to the pulse waveforms of the histogram, and the delay flight time is processed according to the delay time of the delayed photon signals to obtain the flight time corresponding to the light pulses collected by each pixel.
2. The time delay based distance measurement system of claim 1, wherein: the transmitter is configured to transmit a time-coded optical pulse train towards a target area; wherein the time code is a single time code or multiple time codes.
3. The time delay based distance measurement system of claim 1, wherein: the emitter is configured as a light source array composed of a plurality of light sources, and the light source array has a one-to-one correspondence with the pixel units.
4. A time delay based distance measurement system according to claim 3, wherein: the control and processing circuit controls the light sources corresponding to the pixels to emit coded pulse beams coded at different times respectively, and the coded pulse beams are recorded as coded pulse strings.
5. The time delay based distance measurement system of claim 1, wherein: the control and processing circuit controls the emitters to sequentially emit light pulses with different coding modes, and simultaneously controls part of pixels to be on and other pixels to be in an off state.
6. A time delay based distance measurement system according to any one of claims 4 or 5, wherein: the control and processing circuit searches in the histogram according to the coded pulse waveform to obtain a pulse waveform matched with the coded pulse waveform, and obtains the delay flight time according to the matched pulse waveform.
7. The distance measurement method based on time delay is characterized by comprising the following steps:
s1, controlling an emitter to emit a pulse light beam towards a target area, wherein at least part of the pulse light beam is reflected by the target area to form a reflected light beam;
s2, receiving at least part of pulse light beams in the reflected light beams through a collector, wherein the collector comprises a pixel unit consisting of a plurality of pixels, receiving photons in the light pulses through the pixels, and outputting photon signals indicating the collected photons;
step S3, a control and processing circuit delays photon signals generated by photons received by each pixel to obtain delayed photon signals with different time delays, the delayed photon signals of a plurality of pixels are collected through a TDC circuit to obtain photon counting strings, a histogram is drawn based on the photon counting strings, a plurality of non-coincident pulse waveforms are obtained in the histogram, and delay flight time corresponding to each pixel is determined according to the pulse waveforms of the histogram;
and S4, performing time restoration according to the delay flight time and the delay time of the delay photon signal to obtain the flight time corresponding to the light pulse received by each pixel.
8. The time delay based distance measurement method of claim 7, wherein: the control and processing circuit comprises a delay control circuit, a TDC circuit and a histogram circuit; the delay control circuit is connected with pixels in the pixel units to process photon signals generated by photons received by the pixels, so as to obtain delayed photon signals with time delay; the TDC circuitry is configured to collect the delayed photon signals of a plurality of pixels to obtain the photon counting string; the histogram circuit is used for drawing the histogram according to the photon counting string.
9. The time delay based distance measurement method of claim 7, wherein: the emitter is configured as a light source array composed of a plurality of light sources, and the light source array has a one-to-one correspondence with the pixel units; the control and processing circuit respectively controls each light source corresponding to each pixel to emit coded pulse light beams with different codes, each pixel receives different coded light pulses, corresponding matching waveforms are searched in the histogram according to each coded pulse waveform, and the delay flight time is determined according to the waveforms.
10. The time delay based distance measurement method of claim 7, wherein: the emitters sequentially emit light pulses having different coding modes while controlling some pixels to be on and others to be off.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010311685.7A CN111487637B (en) | 2020-04-20 | 2020-04-20 | Distance measurement system and method based on time delay |
| PCT/CN2020/141730 WO2021212914A1 (en) | 2020-04-20 | 2020-12-30 | Time delay-based distance measurement system and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010311685.7A CN111487637B (en) | 2020-04-20 | 2020-04-20 | Distance measurement system and method based on time delay |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111487637A CN111487637A (en) | 2020-08-04 |
| CN111487637B true CN111487637B (en) | 2023-12-01 |
Family
ID=71795082
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010311685.7A Active CN111487637B (en) | 2020-04-20 | 2020-04-20 | Distance measurement system and method based on time delay |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN111487637B (en) |
| WO (1) | WO2021212914A1 (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111487637B (en) * | 2020-04-20 | 2023-12-01 | 深圳奥锐达科技有限公司 | Distance measurement system and method based on time delay |
| CN112100449B (en) * | 2020-08-24 | 2024-02-02 | 深圳市力合微电子股份有限公司 | d-ToF distance measurement optimizing storage method for realizing dynamic large-range and high-precision positioning |
| CN112255636A (en) * | 2020-09-04 | 2021-01-22 | 奥诚信息科技(上海)有限公司 | Distance measuring method, system and equipment |
| CN112198519B (en) * | 2020-10-01 | 2024-05-03 | 奥比中光科技集团股份有限公司 | Distance measurement system and method |
| CN111929662B (en) * | 2020-10-12 | 2020-12-15 | 光梓信息科技（上海）有限公司 | Sensing device |
| CN112731425B (en) * | 2020-11-29 | 2024-05-03 | 奥比中光科技集团股份有限公司 | Histogram processing method, distance measurement system and distance measurement equipment |
| CN112596069B (en) * | 2020-12-04 | 2024-08-27 | Oppo（重庆）智能科技有限公司 | Distance measuring method and system, computer readable medium and electronic device |
| CN112731427B (en) * | 2020-12-21 | 2024-07-12 | 奥比中光科技集团股份有限公司 | Distance measurement system and method based on TOF and electronic equipment |
| CN117716256A (en) * | 2021-07-16 | 2024-03-15 | 深圳市速腾聚创科技有限公司 | Time-of-flight measurement method, circuit, device, storage medium and electronic equipment |
| CN114185057B (en) * | 2021-11-10 | 2024-05-17 | 华为技术有限公司 | Detection method, detection device and terminal |
| CN114236505A (en) * | 2021-12-20 | 2022-03-25 | 奥诚信息科技(上海)有限公司 | DToF-based measurement system and method |
| CN115616608B (en) * | 2022-12-19 | 2023-08-11 | 中国科学院西安光学精密机械研究所 | Single photon three-dimensional imaging distance super-resolution method and system |
| CN118795484A (en) * | 2023-04-11 | 2024-10-18 | 深圳奥锐达科技有限公司 | Laser radar and detection method based on pulse coding |
| CN116359935B (en) * | 2023-05-22 | 2023-08-11 | 苏州洞悉科技有限公司 | Gating imaging ranging system and ranging method |
| CN118033655A (en) * | 2023-11-22 | 2024-05-14 | 深圳市中图仪器股份有限公司 | Distance measuring device and distance measuring method for expanding frequency modulation continuous wave distance measuring range |
| CN118041444B (en) * | 2024-04-08 | 2024-06-14 | 中国科学院空间应用工程与技术中心 | Method for calculating transmission time delay of optical pulse signal |
| CN118151136A (en) * | 2024-05-11 | 2024-06-07 | 深圳阜时科技有限公司 | Receiving module, self-checking module, laser radar and electronic equipment |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110312945A (en) * | 2016-12-30 | 2019-10-08 | 爱丁堡大学董事会 | Photon sensor device |
| CN110632578A (en) * | 2019-08-30 | 2019-12-31 | 深圳奥锐达科技有限公司 | System and method for time-coded time-of-flight distance measurement |
| CN110954918A (en) * | 2019-12-06 | 2020-04-03 | 北京石头世纪科技股份有限公司 | Pulse distance measuring device and method and automatic cleaning equipment with device |
| CN111025318A (en) * | 2019-12-28 | 2020-04-17 | 深圳奥比中光科技有限公司 | Depth measuring device and measuring method |
| CN111025321A (en) * | 2019-12-28 | 2020-04-17 | 深圳奥比中光科技有限公司 | Variable-focus depth measuring device and measuring method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0933649A3 (en) * | 1998-01-28 | 2002-03-27 | Nikon Corporation | Distance measurement apparatus |
| US9819930B2 (en) * | 2015-05-26 | 2017-11-14 | Omnivision Technologies, Inc. | Time of flight imaging with improved initiation signaling |
| EP3608688B1 (en) * | 2018-08-09 | 2021-01-27 | OMRON Corporation | Distance measuring device |
| CN110596721B (en) * | 2019-09-19 | 2022-06-14 | 深圳奥锐达科技有限公司 | Flight time distance measuring system and method of double-shared TDC circuit |
| CN111487637B (en) * | 2020-04-20 | 2023-12-01 | 深圳奥锐达科技有限公司 | Distance measurement system and method based on time delay |
| CN111487638B (en) * | 2020-04-20 | 2023-05-16 | 深圳奥锐达科技有限公司 | Distance measurement system and method based on time delay |
-
2020
- 2020-04-20 CN CN202010311685.7A patent/CN111487637B/en active Active
- 2020-12-30 WO PCT/CN2020/141730 patent/WO2021212914A1/en active Application Filing
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110312945A (en) * | 2016-12-30 | 2019-10-08 | 爱丁堡大学董事会 | Photon sensor device |
| CN110632578A (en) * | 2019-08-30 | 2019-12-31 | 深圳奥锐达科技有限公司 | System and method for time-coded time-of-flight distance measurement |
| CN110954918A (en) * | 2019-12-06 | 2020-04-03 | 北京石头世纪科技股份有限公司 | Pulse distance measuring device and method and automatic cleaning equipment with device |
| CN111025318A (en) * | 2019-12-28 | 2020-04-17 | 深圳奥比中光科技有限公司 | Depth measuring device and measuring method |
| CN111025321A (en) * | 2019-12-28 | 2020-04-17 | 深圳奥比中光科技有限公司 | Variable-focus depth measuring device and measuring method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111487637A (en) | 2020-08-04 |
| WO2021212914A1 (en) | 2021-10-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111487637B (en) | Distance measurement system and method based on time delay | |
| CN111487638B (en) | Distance measurement system and method based on time delay | |
| CN111856485B (en) | Distance measuring system and measuring method | |
| CN112639527B (en) | Adaptive coding for lidar systems | |
| CN110596722B (en) | System and method for measuring flight time distance with adjustable histogram | |
| US10502816B2 (en) | Ranging apparatus | |
| CN111830530B (en) | Distance measuring method, system and computer readable storage medium | |
| CN111856433B (en) | Distance measuring system and measuring method | |
| CN110609291B (en) | System and method for time-coded time-of-flight distance measurement | |
| CN110632578B (en) | System and method for time-encoded time-of-flight distance measurement | |
| JP6938472B2 (en) | Systems and methods for measuring distances to objects | |
| CN110632577B (en) | Time code demodulation processing circuit and method | |
| CN110632576B (en) | Time coding demodulation processing circuit and method | |
| JP2022531578A (en) | Temporal jitter in lidar systems | |
| CN111796295B (en) | Collector, manufacturing method of collector and distance measuring system | |
| CN111766596A (en) | Distance measuring method, system and computer readable storage medium | |
| CN111025321B (en) | Variable-focus depth measuring device and measuring method | |
| CN212341461U (en) | Distance measuring system based on time delay | |
| CN111796296A (en) | Distance measuring method, system and computer readable storage medium | |
| CN111025319A (en) | Depth measuring device and measuring method | |
| US20220099814A1 (en) | Power-efficient direct time of flight lidar | |
| US20230273304A1 (en) | Efficient Fault Detection For Lidar Sensors | |
| CN115267744A (en) | Flight time distance measuring method and device | |
| CN113820725A (en) | System and method for performing time-of-flight measurement and electronic device | |
| CN114236504A (en) | dToF-based detection system and light source adjusting method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |