WO2023092895A1 - 一种光学测量系统 - Google Patents

一种光学测量系统 Download PDF

Info

Publication number
WO2023092895A1
WO2023092895A1 PCT/CN2022/080512 CN2022080512W WO2023092895A1 WO 2023092895 A1 WO2023092895 A1 WO 2023092895A1 CN 2022080512 W CN2022080512 W CN 2022080512W WO 2023092895 A1 WO2023092895 A1 WO 2023092895A1
Authority
WO
WIPO (PCT)
Prior art keywords
polarizer
light
histogram
measurement system
polarization
Prior art date
Application number
PCT/CN2022/080512
Other languages
English (en)
French (fr)
Inventor
金宇
Original Assignee
奥诚信息科技(上海)有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 奥诚信息科技(上海)有限公司 filed Critical 奥诚信息科技(上海)有限公司
Publication of WO2023092895A1 publication Critical patent/WO2023092895A1/zh

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • 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
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • 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

Definitions

  • the present application relates to the technical field of measuring equipment, in particular to an optical measuring system.
  • Time of Flight (ToF) technology can be used to measure the distance of the target to obtain a depth image containing the depth value of the target.
  • Optical measurement systems based on ToF technology have been widely used in consumer electronics, unmanned driving, AR/VR and other fields.
  • An optical measurement system based on ToF technology usually includes a transmitter and a collector. The transmitter emits a beam to irradiate the target field of view and the collector collects the reflected beam, and calculates the flight time of the beam from emission to reception to calculate the distance of the object.
  • ToF technology is divided into direct time of flight (Direct ToF, dToF) technology and indirect time of flight (Indirect ToF, iToF) technology.
  • dToF technology is based on time-correlated single photon counting (TCSPC) technology to measure the flight time of photons in the beam from emission to reception; iToF technology measures the phase delay of the reflected beam relative to the emitted beam, and then calculates the flight time based on the phase delay.
  • TCSPC time-correlated single photon counting
  • the collector inevitably receives the ambient light signal when receiving the emitted optical signal.
  • the signal light is relatively The intensity of the signal is small, which causes the signal-to-noise ratio to be too low during signal demodulation, which in turn leads to a decrease in measurement accuracy.
  • the purpose of the embodiments of the present application is to provide an optical measurement system, aiming to solve one or more technical problems in related technologies.
  • an embodiment of the present application provides an optical measurement system, including: a transmitter configured to emit linearly polarized light having at least two different polarization directions to a target; At least two linearly polarized lights with different polarization directions reflected back by the object, and generate photon signals corresponding to each polarization direction; a readout circuit configured to receive the photons corresponding to each polarization direction and process them to generate a fusion histogram; and a processor configured to synchronize the transmitter and the collector, and calculate the distance of the target object according to the fusion histogram.
  • the readout circuit includes a TDC circuit array, a histogram circuit array, and an adder
  • the TDC circuit array is configured to generate the time corresponding to each polarization direction according to the photon signal corresponding to each polarization direction signal
  • the histogram circuit array is correspondingly configured to generate a histogram corresponding to each polarization direction according to the time signal corresponding to each polarization direction
  • the adder is configured to add the histograms corresponding to each polarization direction to obtain the fused histogram
  • the readout circuit includes at least one TDC circuit and a histogram circuit, the at least one TDC circuit is configured to generate a time signal corresponding to each polarization direction according to the photon signal corresponding to each polarization direction, and the histogram circuit is configured to The time signals corresponding to each polarization direction are accumulated to generate the fusion histogram.
  • the transmitter includes a light source array composed of a plurality of light sources and a driver connected to the light sources, at least one of the light sources is driven by the driver and controlled by the processor in time sequence Emitting the linearly polarized light in at least two different polarization directions;
  • the collector includes a pixel array composed of a plurality of pixels, superpixels or composite pixels and a polarization polarizer arranged on the light incident side of each pixel, superpixel or composite pixel
  • the at least one light source is set in one-to-one correspondence with at least one pixel, superpixel or combined pixel, and under the control of the processor, the pixel, superpixel corresponding to the at least one light source Or, the polarizer on the light incident side of the combined pixel changes the polarization direction synchronously with the linearly polarized light.
  • the emitter includes a light source array composed of a plurality of light sources and a polarizer disposed on the light output side of the light source array;
  • the collector includes a pixel array composed of a plurality of pixels, superpixels or combined pixels and a polarizer disposed on the light-incident side of the pixel array, the polarizer and the polarizer are both adjustable polarizers, and the polarizer and the polarizer change the polarization direction synchronously according to time sequence.
  • the emitter includes a light source array composed of a plurality of light sources and a plurality of polarizers arranged on the light output side of each of the light sources, and the polarization directions of each of the polarizers are different;
  • the collector includes A pixel array composed of a plurality of pixels, super-pixels or combined pixels and a plurality of polarizers arranged on the light-incident side of each of the pixels, super-pixels or combined pixels, each polarizer has a different polarization direction, and the light source and the pixel
  • the plurality of polarizers corresponding to each other and the polarization directions of the plurality of polarizers are set to be the same in one-to-one correspondence.
  • the at least two different polarization directions include two orthogonal polarization directions.
  • the pixel, superpixel or subpixel comprises a plurality of SPADs
  • the light source comprises a VCSEL light source
  • the polarizer is a polarizer, a liquid crystal polarization grating, or a composite film layer with polarization properties.
  • the emitter further includes an emitting optical element, and the emitting optical element is used for projecting the linearly polarized light onto the target, and forming the linearly polarized light on the target Illumination spot;
  • the collector also includes a receiving optical element, the optical receiving element, the polarizer and the pixel array are sequentially arranged along the propagation path of the linearly polarized light, and the receiving optical element is used to be The linearly polarized light reflected by the object is imaged to the pixel array.
  • the beneficial effect of the embodiment of the present application is that: the emitter emits linearly polarized light with different polarization directions, and the collector can collect linearly polarized light with different polarization directions reflected by the target, which can reduce the interference of ambient light and improve the signal-to-noise of the measurement system Ratio, thereby improving the accuracy of the measurement system.
  • FIG. 1 is a schematic structural diagram of an optical measurement system provided by an embodiment of the present application.
  • FIG. 2 is a schematic structural diagram of another optical measurement system provided by an embodiment of the present application.
  • FIG. 3A is a schematic structural diagram of another optical measurement system provided by an embodiment of the present application.
  • FIG. 3B is a schematic structural diagram of another optical measurement system provided by an embodiment of the present application.
  • FIG. 3C is a schematic structural diagram of another optical measurement system provided by an embodiment of the present application.
  • FIG. 4 is a schematic structural diagram of another optical measurement system provided by an embodiment of the present application.
  • FIG. 5 is a schematic structural diagram of another optical measurement system provided by an embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of another optical measurement system provided by an embodiment of the present application.
  • first and second are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as “first” and “second” may explicitly or implicitly include one or more of these features.
  • “plurality” means two or more, unless otherwise specifically defined.
  • the embodiment of the present application provides an optical measurement system 10 for measuring the distance of a target object 20 .
  • the optical measurement system 10 includes a transmitter 11 , a collector 12 and a processor 13 .
  • the transmitter 11 is arranged to transmit an optical signal having a linear polarization state with at least two polarization directions towards the target object 20 .
  • the optical signal is a pulsed beam 30 .
  • the collector 12 is used for receiving the light signal reflected by the target object 20 . It can be understood that at least part of the pulsed beam 30 is reflected by the target 20 to form a reflected beam 40 and returns to the collector 12 .
  • the collector 12 includes a pixel unit 121 and a polarizer 122.
  • the polarizer 122 is a polarizer with an adjustable polarization direction. The polarization direction of the polarizer 122 is switched to be the same as that of the optical signal.
  • the polarizer 122 is used to transmit The optical signal in the linear polarization state reflected back by 20, the pixel unit 121 is used to receive the optical signal passing through the polarizer 122 and generate a sampling signal.
  • the transmitter 11 emits linearly polarized light in at least two polarization directions in time sequence under the control of the processor 13, and then the polarizer 122 arranged in front of the pixel unit 121 switches the polarization directions synchronously under the control of the processor 13, Used to receive linearly polarized light emitted by the transmitter.
  • the processor 13 synchronizes the polarization direction of the linearly polarized light emitted by the transmitter 11 and the polarizer 122, and the linearly polarized light and the polarizer 122 switch the polarization direction synchronously according to the timing under the control of the processor 13, and the reflected light signal first passes through the The polarizer 122 is then collected by the pixel unit 121 .
  • the polarizer 122 allows the reflection of all linear polarization states The optical signal passes through; when the polarization direction of the optical signal in the linear polarization state and the polarization direction of the polarizer 122 are at an angle of 0° to 90°, the polarizer 122 allows the reflected part of the optical signal in the linear polarization state to pass; when the polarization direction of the linear polarization state When the polarization direction of the optical signal and the polarization direction of the polarizer 122 form an angle of 90° (that is, the two polarization directions are perpendicular or the angle between them is equal to 90°), the polarizer 122 prevents all reflected optical signals of linear polarization from passing through.
  • the processor 13 is connected to the transmitter 11 and the collector 12 respectively, and controls the transmitter 11 and the collector 12 synchronously.
  • the processor 13 receives the sampling signal and analyzes and calculates the distance of the target 20 based on the light signal emitted by the transmitter 11 .
  • the processor 13 synchronizes the trigger signals of the emitter 11 and the collector 12 to calculate the time-of-flight of the photons in the pulse beam 30 from emission to reception, and calculate the distance of the target 20 according to the time-of-flight.
  • the collector 12 when the collector 12 collects the reflected light signal, the light signal sent by the light source 111 and the ambient light signal are collected by the collector 12 at the same time, but the polarizer 122 can prevent the light signal with a different polarization direction from passing through, so that Only the reflected light signal with the same polarization direction as the polarizer 122 can pass through without loss, and the reflected light signal is incident on the pixel unit 121 after passing through the polarizer 122 .
  • the optical signal incident on the polarizer 122 and the optical signal passing through the polarizer 122 satisfy the following relationship:
  • C incident represents the optical signal incident to the polarizer 122
  • C through represents the optical signal passing through the polarizer 122
  • ⁇ represents the included angle between the polarization direction of the polarized light and the polarization direction of the polarizer 122 .
  • the polarization direction of the polarizer 122 is set to be the same as the polarization direction of the optical signal.
  • the polarization direction of the ambient light is isotropic, it can be equivalent to the superposition of two polarization components with the same energy and perpendicular polarization directions.
  • the polarization component light parallel to the polarization direction of the polarizer 122 can pass without loss; while the polarization component light perpendicular to the polarization direction of the polarizer 122 cannot pass through at all. Therefore, part of the ambient light passing through the polarizer 122 will be lost, and the energy of the lost ambient light is about 50%, which effectively improves the signal-to-noise ratio of the measurement, thereby improving the measurement accuracy of the optical measurement system 10 .
  • the pixel unit 121 includes a plurality of pixels for collecting optical signals, and the plurality of pixels form a one-dimensional or two-dimensional pixel array, and the pixels may be, for example, an avalanche photodiode (Avalanche Photon Diode, APD), a single Photon avalanche photodiode (Single Photon Avalanche Diode, SPAD) and silicon photomultiplier (Silicon Photomultiplier, SiPM) are one of the single photon devices that collect photons.
  • APD avalanche photodiode
  • SPAD Single Photon Avalanche Diode
  • SiPM silicon photomultiplier
  • the pixel array is a SPAD-based pixel array
  • the pixel array includes a SPAD array composed of a plurality of SPADs
  • the SPAD can respond to a single photon of the incident optical signal and output an indication that the received photon arrives at each SPAD correspondingly.
  • the photon signal of time In this way, when the emitter switches linearly polarized light with different polarization directions in time sequence, the SPAD pixel can output photon signals corresponding to different polarization directions in time sequence.
  • each pixel may include one or more SPADs.
  • the optical measurement system further includes a readout circuit (not shown in FIG. 1 ), the pixel unit 121 is connected to the readout circuit, and the readout circuit is connected to the processor 13 .
  • the readout circuit is connected to the collector 12 and acquires the sampling signal according to the photon signal generated by the pixel unit 121 , and the processor 13 receives the sampling signal and calculates the distance of the target object 20 according to the sampling signal.
  • the sampling signal may be expressed in a form such as time stamp data, digital time series signal or event occurrence time.
  • the readout circuit is composed of one or more of devices such as a signal amplifier, a time-to-digital converter (Time-to-Digital Converter, TDC), and a digital-to-analog converter (ADC).
  • the readout circuit can be integrated with the processor as part of the processor 13; in other embodiments, the readout circuit can be integrated with the pixel unit 121 as a part of the processor 13; Part of the collector 12.
  • the present application does not specifically limit the implementation form of the readout circuit.
  • the one-to-one correspondence between the emission field of view of the light source and the collection field of view of the pixel Every time the emitter emits a light spot to the target field of view, it will be reflected and imaged on the corresponding pixel.
  • multiple pixels can be combined to form a "composite pixel" or "super pixel” to collect the light signals in the corresponding reflected light spots, for example, 2*2 pixels are one Combined pixels, 2*2 combined pixels are a super pixel.
  • the one-to-one correspondence between light sources and pixels is used as an exemplary description to illustrate the embodiments or examples. It should be understood that the exemplary descriptions should not be interpreted as application-specific restrictions.
  • the readout circuit includes a TDC circuit and a histogram circuit, and each pixel in the collector 12 is correspondingly connected to a TDC circuit and a histogram circuit.
  • the collector 12 switches the polarization directions of the polarizers in time sequence, so as to sequentially receive linearly polarized light in at least two polarization directions and generate photon signals according to the emission sequence of the transmitter, and the TDC circuit is used to receive and calculate the time interval of these photon signals, and The time interval is converted into a time code, and the histogram circuit cumulatively counts the time code output by the TDC circuit to draw a histogram.
  • the processor 13 calculates the flight time of the photon from emission to reception according to the histogram, and can further calculate the distance of the target object 20 .
  • the pixel corresponding to the light source that is turned on includes one or more SPADs, one or more SPADs are connected to the same TDC circuit and histogram circuit, and one or more SPADs output photon signals to the TDC circuit, the TDC circuit is connected to the histogram circuit, and the histogram circuit is connected to the processor.
  • different pixels, superpixels or combined pixels can be sequentially activated in sequence, and multiple SPADs included in different pixels, superpixels or combined pixels can be connected to the same TDC circuit and histogram circuit.
  • the polarizer 122 is a polarizer, and the polarizer is spaced apart from the pixel unit 121 (or pixel array).
  • the polarizer may include a molecular type or a microcrystalline type, or the like.
  • the polarizer 122 is a liquid crystal polarization grating, and the liquid crystal polarization grating is spaced apart from the pixel unit 121 (or pixel array).
  • the polarizer 122 is a composite film layer with polarization properties, and the composite film layer is plated on the pixel unit 121 (or pixel array) through a coating process.
  • the collector 12 further includes a receiving optical element 123, the optical receiving element 123, the polarizer 122, and the pixel unit 121 are sequentially arranged along the propagation path of the optical signal, and the receiving optical element 123 is used for The light signal reflected by the object 20 is imaged to the pixel unit 121 .
  • the transmitter 11 includes a first light source 111 and a first driver 113 for driving the first light source 111, and the first light source 111 is driven by the first driver 113 and in the processor. Under control, optical signals of linear polarization states with different polarization directions are emitted in time sequence.
  • the first light source 111 is a vertical cavity surface emitting laser (Vertical Cavity Surface Emitting Laser, VCSEL). In order to make the VCSEL emit a stable optical signal with a linear polarization state, it is necessary to perform polarization control processing on the VCSEL to obtain a polarization-controlled VCSEL. light source.
  • VCSEL Vertical Cavity Surface Emitting Laser
  • the polarization treatment includes growing chip structures, external cavity feedback structures, semiconductor gratings, surface relief structures, etc. on the surface of the light exit hole of the VCSEL.
  • the VCSEL light source based on polarization control can emit linearly polarized light with different polarization directions. When the linearly polarized light is projected to the target object 20 , the reflected light signal reflected by the target object 20 is still linearly polarized light, and the polarization direction will not change.
  • the first light source 111 and the polarizer 122 switch polarization directions synchronously under the control of the processor, and the polarization direction of the linearly polarized light emitted by the first light source 111 is the same as that of the polarizer 122 .
  • the transmitter 11 includes a second light source 111, a polarizer (not shown in the figure) and a second driver 113, and the polarizer is arranged on the output light of the second light source 111.
  • the polarizer is a polarizer with adjustable polarization direction
  • the second light source 111 is driven by the second driver 113 and under the control of the processor to emit an optical signal without polarization state
  • the polarizer is used for the second light source 111
  • the resulting optical signal with no polarization state is modulated into an optical signal with a linear polarization state.
  • the non-polarized optical signal emitted by the second light source 111 becomes a linearly polarized optical signal after passing through the polarizer, and the polarization direction of the optical signal passing through the polarizer is the same as that of the polarizer, that is, the polarized
  • the polarization direction of the polarizer and the polarizer are switched synchronously under the control of the processor, and the polarization direction of the polarizer is the same as that of the polarizer.
  • the polarizer can also be a polarizer, and the polarizer is spaced from the second light source 111; or, the polarizer can also be a liquid crystal polarization grating, and the polarizer is spaced from the second light source 111; or, the polarizer
  • the polarizer can also be a composite film layer with polarizing properties, and the composite film layer is plated on the light source through a coating process.
  • the polarizer and the analyzer are switched synchronously in two orthogonal polarization directions.
  • the polarization directions of the polarizer and the analyzer are both horizontal
  • the polarization directions of the polarizer and the analyzer are both vertical.
  • the two polarization directions of the first time period and the second time period are set orthogonally.
  • the transmitter 11 further includes a transmitting optical element 112, and the transmitting optical element 112 is used to project an optical signal in a linearly polarized state to the target object 20, and make the optical signal An illumination spot is formed on the target object 20 .
  • the emitting optical element 112 includes, but is not limited to, one or a combination of collimating mirrors, diffractive optical elements, and the like.
  • the polarizer can be arranged between the light source 111 and the emitting optical element 112; or, it can be arranged between some two emitting optical elements 112; or, it can be arranged on the light exit side of all emitting optical elements 112 , the embodiment of the present application does not specifically limit the location of the polarizer.
  • the light source (including the aforementioned first light source or second light source) is a VCSEL array light source chip formed by generating multiple VCSEL light sources on a single semiconductor substrate.
  • the light source can transmit the pulse beam 30 to the target object 20 at a certain frequency (or pulse period), and the pulse beam 30 is projected onto the target object 20 through the emitting optical element 112 to form an illumination spot.
  • the collector receives at least two linearly polarized lights with different polarization directions in time sequence, and then performs cumulative counting in the same histogram circuit to obtain a histogram, and the histogram will be Higher signal-to-noise ratio can further improve the anti-interference performance of the optical measurement system, thereby improving the accuracy of the system.
  • the polarizer is not an adjustable polarizer, and multiple non-adjustable polarizers are arranged in front of the pixels of the collector.
  • the polarization directions of the multiple polarizers are different, and can be used to transmit linearly polarized light of different polarization modes, respectively.
  • the linearly polarized light is emitted sequentially by the emitter.
  • two types of polarizers are used, and the transmitter emits two kinds of linearly polarized lights whose polarization directions are orthogonal to each other in time sequence as an exemplary description.
  • the polarization directions of the two kinds of polarizers are respectively related to same direction of polarization.
  • a light source is turned on to emit two kinds of linearly polarized light with different polarization directions in time sequence
  • the pixel corresponding to the turned on light source includes a plurality of SPADs, and two polarizers are arranged side by side on the light incident side of the plurality of SPADs.
  • the polarization directions of the two polarizers are orthogonal.
  • a group of SPADs corresponding to the same polarizer is connected to the same TDC circuit and histogram circuit, and two groups of SPADs corresponding to different polarizers, namely the first group of SPADs and the second group of SPADs, A TDC circuit and a histogram circuit are respectively connected; the two histogram circuits are respectively connected to an adder, and the adder adds the histograms generated by the two histogram circuits to obtain a new histogram, that is, a fusion histogram.
  • the adder can be connected to a processor, and the processor can calculate the distance of the target object according to the new histogram.
  • two groups of SPADs corresponding to different polarizers are connected to the same TDC circuit and histogram circuit.
  • the histogram circuit can be connected to a processor, and the processor can calculate the distance of the target object according to the histogram. It should be noted that, in the embodiment shown in FIG. 3B , since the two groups of SPADs are connected to the same TDC circuit and histogram circuit, it is also possible not to group the SPADs corresponding to different polarizers, and treat the two groups of SPADs as a whole. In another embodiment, as shown in FIG.
  • the histogram circuit can be connected to a processor, and the processor can calculate the distance of the target object according to the histogram.
  • FIG. 1 and FIG. 2 another embodiment of the present application provides an optical measurement system.
  • multiple polarizers are arranged in front of the light source of the transmitter, and the polarization directions of the multiple polarizers are different, and the transmitter can simultaneously emit linearly polarized light in multiple polarization modes.
  • the present embodiment is the same as the foregoing embodiment, which will not be repeated here, and please refer to the foregoing.
  • the optical measurement system includes a transmitter, a collector, a readout circuit and a processor.
  • the emitter includes a light source array composed of multiple light sources and multiple polarizers arranged on the light incident side of each light source, and the polarization directions of the multiple polarizers are different.
  • the collector includes a pixel array composed of a plurality of pixels and a plurality of polarizers arranged on the light-incident side of each pixel.
  • the light source and the pixel are set in one-to-one correspondence, the polarizer and the polarizer are both adjustable polarizers, and the corresponding polarizer and polarizer change the polarization direction synchronously according to time sequence, wherein the above-mentioned pixel can also be a composite pixel or a super pixel.
  • two polarizers ie, a first polarizer 421 and a second polarizer 422 , are arranged in parallel in front of the VCSEL light source 41 .
  • two polarizers are arranged in parallel, that is, the first polarizer 431 and the second polarizer 432.
  • the group of SPADs includes at least one SPAD, the first group of SPADs 441 is preceded by a first polarizer 431 , and the second group of SPADs 442 is preceded by a second polarizer 432 .
  • the polarization direction of the polarizers corresponding to each other is the same as that of the polarizer, so that the SPAD can collect the reflected light in a linearly polarized state.
  • the first group of SPAD441 receives the linearly polarized light of the first polarization direction reflected back by the target and generates a first photon signal corresponding to the first polarization direction
  • the second group of SPAD442 receives the linearly polarized light of the second polarization direction reflected back by the target light and generate a second photon signal corresponding to the second polarization direction.
  • the polarization directions of the two polarizers are set orthogonally, one is the horizontal direction, and the other is the vertical direction; the polarization directions of the two polarizers are set orthogonally, one is the horizontal direction, and the other is the vertical direction .
  • the first group of SPAD441 is connected to the first TDC circuit 451 and the first histogram circuit 461
  • the second group of SPAD442 is connected to the second TDC circuit 452 and the second histogram circuit 462.
  • a histogram circuit 461 and a second histogram circuit 462 are connected to the adder 47 .
  • the first TDC circuit 451 generates the first time signal according to the first photon signal corresponding to the first polarization direction, and the first histogram circuit 461 generates the first histogram according to the first time signal corresponding to the first polarization direction;
  • the second TDC The circuit 452 generates a second time signal according to the second photon signal corresponding to the second polarization direction, and the second histogram circuit 462 generates a second histogram according to the second time signal corresponding to the second polarization direction.
  • the adder 47 adds the first histogram generated by the first histogram circuit 461 and the second histogram generated by the second histogram circuit 462 to obtain a third histogram.
  • the adder may also be connected to a processor, and the processor may calculate the distance of the target object according to the third histogram.
  • the polarization directions of the first polarizer 421 and the first polarizer 431 are both horizontal directions
  • the polarization directions of the second polarizer 422 and the second polarizer 432 are both vertical directions.
  • the second polarizer 422 emits linearly polarized light whose polarization direction is the vertical direction; after being reflected by the target, the linearly polarized light whose polarization direction is the horizontal direction passes through the first polarizer 431 and is collected by the first group of SPAD441 to generate the second polarizer.
  • linearly polarized light with a vertical polarization direction passes through the second polarizer 432 and is collected by the second group of SPADs 442 to generate a second photon signal.
  • VCSEL light sources are used to describe two groups of SPADs. It should be understood that the exemplary description cannot be construed as a specific limitation on the present application.
  • the exemplary description cannot be construed as a specific limitation on the present application.
  • the light emitted by the VCSEL light source passes linearly polarized light of three different polarization directions, that is, when the polarizer includes three different polarization directions, there are three polarizers arranged before the SPAD corresponding to the VCSEL light source, and three The polarization direction of the first polarizer is the same as that of the three polarizers in one-to-one correspondence.
  • the VCSEL light source array includes multiple VCSEL light sources, and the SPAD array includes multiple SPADs.
  • the VCSEL light sources in one area correspond to the SPADs in one area.
  • the SPADs in a certain area correspond to each other one by one to collect reflected optical signals.
  • the collector receives the linearly polarized light of two different polarization directions respectively, and then the adder adds up the histograms counted respectively for different polarization directions to obtain a new histogram, the new The histogram has the diversity performance of 2 times the signal-to-noise ratio, which can further improve the anti-interference performance of the optical measurement system, thereby improving the accuracy of the system.
  • the readout circuit includes a TDC circuit 45 and a histogram circuit 46 .
  • the first group of SPAD441 and the second group of SPAD442 are correspondingly connected to the same TDC circuit 45 and histogram circuit 46 .
  • the TDC circuit 45 is used to receive the first photon signal and the second photon signal, calculate the time interval of each photon signal, and convert the time interval into a corresponding time code.
  • the histogram circuit 46 counts the time code output from the TDC circuit 45 to draw a histogram.
  • the histogram circuit 46 is connected to a processor, and the processor can calculate the flight time of the photon from emission to reception according to the histogram, and can further calculate the distance of the target.
  • the first group of SPAD441 is correspondingly connected to the same first TDC circuit 451
  • the second group of SPAD442 is correspondingly connected to the same second TDC
  • the circuit 452 , the first TDC circuit 451 and the second TDC circuit 452 are connected to the same histogram circuit 46 .
  • the first TDC circuit 451 receives the first photon signal, calculates a first time interval of the first photon signal, and converts the first time interval into a corresponding time code.
  • the second TDC circuit 452 receives the second photon signal, calculates a second time interval of the second photon signal, and converts the second time interval into a corresponding time code.
  • the histogram circuit 46 cumulatively counts the time codes output by the first TDC circuit 451 and the second TDC circuit 452 to draw a histogram.
  • the histogram circuit 46 may be connected to a processor, and the processor may calculate the flight time of the photon from emission to reception according to the histogram, and further calculate the distance of the target.

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

一种光学测量系统（10），包括：发射器（11），配置为向目标物（20）发射具有至少两个不同偏振方向的线偏振光（30）；采集器（12），配置为分别接收被目标物（20）反射回的至少两个不同偏振方向的线偏振光（40），并生成各偏振方向对应的光子信号；读出电路，配置为接收各偏振方向对应的光子信号并进行处理生成融合直方图；处理器（13），配置为同步发射器（11）和采集器（12），并根据融合直方图计算目标物（20）的距离，可以提高光学测量系统（10）的抗干扰能力，从而提升光学测量系统（10）的信噪比。

Description

一种光学测量系统
本申请要求于2021年11月23日提交中国专利局，申请号为202122887094.7，发明名称为“一种光学测量系统”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
本申请涉及测量设备技术领域，尤其涉及一种光学测量系统。
背景技术
利用飞行时间(Time of Flight，ToF)技术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。基于ToF技术的光学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ToF技术的光学测量系统通常包括发射器和采集器，利用发射器发射光束照射目标视场并利用采集器采集反射光束，计算光束由发射到接收的飞行时间来计算物体的距离。ToF技术分为直接飞行时间(Direct ToF，dToF)技术和间接飞行时间(Indirect ToF，iToF)技术。其中，dToF技术基于时间相关单光子计数(TCSPC)技术测量光束中的光子从发射到接收的飞行时间；iToF技术测量反射光束相对于发射光束的相位延迟，再由相位延迟对飞行时间进行计算。
但是，在利用ToF的测距技术中，采集器在接收发射的光信号时不可避免的接收到环境光信号，当环境光过强时或者被测目标距离较远时，信号光相对于环境光的强度较小，引起信号解调时的信噪比过低，进而导致测量准确度降低。
以上背景技术内容的公开仅用于辅助理解本申请的构思及技术方案，其并不必然属于本申请的现有技术，在没有明确的证据表明上述内容在本申请的申请日前已经公开的情况下，上述背景技术不应当用于评价本申请的新颖性和创 造性。
实用新型内容
本申请实施例的目的在于提供一种光学测量系统，旨在解决相关技术中的一个或多个技术问题。
第一方面，本申请一实施例提供一种光学测量系统，包括：发射器，配置为向目标物发射具有至少两个不同偏振方向的线偏振光；采集器，配置为分别接收被所述目标物反射回的至少两个不同偏振方向的线偏振光，并生成各偏振方向对应的光子信号；读出电路，配置为接收所述各偏振方向对应的所述光子并进行处理生成融合直方图；以及处理器，配置为同步所述发射器和所述采集器，并根据所述融合直方图计算所述目标物的距离。
在一些实施例中，所述读出电路包括TDC电路阵列、直方图电路阵列和加法器，所述TDC电路阵列配置为根据所述各偏振方向对应的所述光子信号生成各偏振方向对应的时间信号，所述直方图电路阵列对应配置为根据各偏振方向对应的所述时间信号生成各偏振方向对应的直方图，所述加法器配置为将各偏振方向对应的直方图进行相加得到所述融合直方图；或者
所述读出电路包括至少一个TDC电路和直方图电路，所述至少一个TDC电路配置为根据各偏振方向对应的所述光子信号生成各偏振方向对应的时间信号，所述直方图电路配置为对各偏振方向对应的所述时间信号进行累计以生成所述融合直方图。
在一些实施例中，所述发射器包括多个光源组成的光源阵列和与所述光源连接的驱动器，至少一个所述光源在所述驱动器的驱动下并在所述处理器的控制下按时序发射至少两个不同偏振方向的所述线偏振光；所述采集器包括多个像素、超像素或合像素组成的像素阵列和设置于各所述像素、超像素或合像素入光侧的偏振器，所述至少一个所述光源与至少一个所述像素、超像素或合像素一一对应设置，在所述处理器的控制下，所述至少一个所述光源对应的所述 像素、超像素或合像素入光侧的所述偏振器与所述线偏振光同步改变偏振方向。
在一些实施例中，所述发射器包括多个光源组成的光源阵列和设置于所述光源阵列出光侧的起偏器；所述采集器包括多个像素、超像素或合像素组成的像素阵列和设置于所述像素阵列入光侧的偏振器，所述起偏器和所述偏振器均为可调偏振器，所述起偏器和所述偏振器按照时序同步改变偏振方向。
在一些实施例中，所述发射器包括多个光源组成的光源阵列和设置于各所述光源出光侧的多个起偏器，各所述起偏器的偏振方向不同；所述采集器包括多个像素、超像素或合像素组成的像素阵列和设置于各所述像素、超像素或合像素入光侧的多个偏振器，各偏振器的偏振方向不同，所述光源与所述像素、超像素或合像素一一对应设置，一一对应的多个所述起偏器和多个所述偏振器的偏振方向设置成一一对应相同。
在一些实施例中，所述至少两个不同偏振方向包括两个正交的偏振方向。
在一些实施例中，所述像素、超像素或合像素包括多个SPAD，所述光源包括VCSEL光源。
在一些实施例中，所述偏振器为偏振片、液晶偏振光栅或具有偏振特性的复合膜层。
在一些实施例中，所述发射器还包括发射光学元件，所述发射光学元件用于将所述线偏振光投射至所述目标物，并使所述线偏振光于所述目标物上形成照明斑点；所述采集器还包括接收光学元件，所述光学接收元件、所述偏振器以及所述像素阵列沿所述线偏振光的传播路径依次设置，所述接收光学元件用于将被所述目标物所反射的所述线偏振光成像至所述像素阵列。
本申请实施例的有益效果在于：发射器发射不同偏振方向的线偏振光，采集器可以采集被目标物反射的不同偏振方向的线偏振光，可以减少环境光的干扰，提升测量系统的信噪比，从而提高测量系统的准确度。
附图说明
为了更清楚地说明本申请实施例中的技术方案，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的前提下，还可以根据这些附图获得其他的附图。
图1为本申请一实施例提供的一种光学测量系统的结构示意图。
图2为本申请一实施例提供的另一种光学测量系统的结构示意图。
图3A为本申请一实施例提供的另一种光学测量系统的结构示意图。
图3B为本申请一实施例提供的另一种光学测量系统的结构示意图。
图3C为本申请一实施例提供的另一种光学测量系统的结构示意图。
图4为本申请一实施例提供的另一种光学测量系统的结构示意图。
图5为本申请一实施例提供的另一种光学测量系统的结构示意图。
图6为本申请一实施例提供的另一种光学测量系统的结构示意图。
具体实施方式
为了使本申请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。
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个该特征。在本申请的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
请参阅图1，本申请实施例提供了一种光学测量系统10，其用于对目标物20进行距离测量。光学测量系统10包括发射器11、采集器12以及处理器13。
发射器11设置为向目标物20发射具有至少两个偏振方向的线偏振态的光信号。可选地，光信号为脉冲光束30。采集器12用于接收被目标物20反射回的光信号。可以理解的是，至少部分脉冲光束30经目标物20反射并形成反射光束40而回到采集器12。采集器12包括像素单元121和偏振器122，偏振器122为偏振方向可调的偏振器，偏振器122的偏振方向切换成与光信号的偏振方向相同，偏振器122用于透过被目标物20反射回的线偏振态的光信号，像素单元121用于接收通过偏振器122的光信号并生成采样信号。可选地，发射器11在处理器13的控制下按时序发射至少两个偏振方向的线偏振光，则设置在像素单元121前的偏振器122在处理器13的控制下同步切换偏振方向，以用于接收发射器发射的线偏振光。也就是说，处理器13同步发射器11发射的线偏振光和偏振器122的偏振方向，线偏振光和偏振器122在处理器13的控制下按照时序同步切换偏振方向，反射光信号先经过偏振器122，再被像素单元121采集。可以理解的是，当线偏振态的光信号的偏振方向与偏振器122的偏振方向相同时(即两者的偏振方向平行或夹角等于0)，偏振器122允许反射的全部线偏振态的光信号通过；当线偏振态的光信号的偏振方向与偏振器122的偏振方向呈0°至90°角时，偏振器122允许反射的部分线偏振态的光信号通过；当线偏振态的光信号的偏振方向与偏振器122的偏振方向呈90°角时(即两者的偏振方向垂直或夹角等于90°)，偏振器122阻止反射的全部线偏振态的光信号通过。处理器13分别与发射器11以及采集器12连接，同步控制发射器11以及采集器12，处理器13接收采样信号并基于发射器11所发射的光信号而分析和计算 目标物20的距离。具体地，处理器13同步发射器11与采集器12的触发信号，以计算脉冲光束30中的光子从发射到接收所需要的飞行时间，并根据飞行时间而计算目标物20的距离。
在一个实施例中，当采集器12采集反射光信号时，光源111发出的光信号与环境光信号同时被采集器12采集，但是，偏振器122能够阻止与其偏振方向不同的光信号通过，使只有与偏振器122相同偏振方向的反射光信号可以无损的通过，反射光信号通过偏振器122后，再入射到像素单元121上。这样大部分环境光被阻止通过偏振器122，而只有小部分环境光通过偏振器122，可以提升激光测量系统10的信噪比，从而可以提高激光测量系统10的测量准确度。
可选地，入射到偏振器122的光信号与透过偏振器122的光信号满足如下关系：
C 透过＝C 入射×cos 2(θ)
其中，
C 入射表示入射到偏振器122的光信号；
C 透过表示透过偏振器122的光信号；
θ表示为偏振光的偏振方向与偏振器122的偏振方向的夹角。
因此，在这个实施例中，设置偏振器122的偏振方向与光信号的偏振方向相同，此时，θ＝0，那么被目标物20反射的具有某一偏振方向的线偏振光信号将无损地通过像素单元121前的偏振器122。而由于环境光的偏振方向各向同性，可等效为两个能量相同且偏振方向垂直的偏振分量光的叠加。其中，平行于偏振器122偏振方向的偏振分量光可以无损通过；而垂直于偏振器122偏振方向的偏振分量光则完全不能通过。因此，经过偏振器122的环境光将损失掉一部分，损失的环境光能量大小约为50％，有效的提高了测量的信噪比，从而提高了光学测量系统10的测量准确度。
在一个实施例中，像素单元121包括多个用于采集光信号的像素，多个像素组成一维或二维像素阵列，所述像素可以是诸如雪崩光电二极管(Avalanche  Photon Diode,APD)、单光子雪崩光电二极管(Single Photon Avalanche Diode，SPAD)、和硅基光电倍增管(Silicon Photomultiplier,SiPM)等采集光子的单光子器件中的一种。像素单元121采集到光子的情况被视为光子检测事件，像素单元121响应于光子检测事件并输出光子信号。可选地，像素阵列为基于SPAD的像素阵列，像素阵列包括由多个SPAD组成的SPAD阵列，SPAD可以对入射的光信号的单个光子进行响应并输出指示所接收光子在每个SPAD处相应到达时间的光子信号。这样，当发射器按照时序切换不同偏振方向的线偏振光，则SPAD像素可以按时序输出不同偏振方向对应的光子信号。需要说明的是，每个像素可以包括一个或多个SPAD。
在一些实施例中，光学测量系统还包括读出电路(图1中未示出)，像素单元121连接读出电路，读出电路连接处理器13。读出电路连接采集器12并根据像素单元121生成的光子信号获取采样信号，处理器13接收采样信号并根据采样信号计算出目标物20的距离。可选的，采样信号可以采用诸如时间戳数据、数字时序信号或事件发生时间等的表示形式。可选地，读出电路由信号放大器、时间数字转换器(Time-to-Digital Converter，TDC)、数模转换器(ADC)等器件中的一种或多种组成。
需要说明的是，在一些实现实施例中，读出电路可以与处理器整合在一起，作为处理器13的一部分；在另一些实施例中，读出电路可以与像素单元121整合在一起，作为采集器12的一部分。本申请对读出电路的实现形式不予具体限制。
在基于dToF技术的光学测量系统中，光源的发射视场与像素的采集视场具有一一对应的关系，发射器每发射一个光斑到目标视场后都会反射并成像到对应的像素上。为尽可能多的接收反射光斑的光信号，可以将多个像素组合在一起形成一个“合像素”或“超像素”采集对应的反射光斑中的光信号，例如，2*2个像素为一个合像素，2*2个合像素为一个超像素。为了方便描述，在后续的一些实施例或示例中，将光源与像素一一对应的对应关系作为示例性描述， 对实施例或示例进行说明，应当理解的是，示例性描述不应解释为对本申请的具体限制。
在一个实施例中，读出电路包括TDC电路和直方图电路，采集器12中每个像素对应连接一个TDC电路和一个直方图电路。采集器12按照时序切换偏振器的偏振方向，以按照发射器的发射顺序依次接收至少两个偏振方向的线偏振光并生成光子信号，TDC电路用于接收和计算这些光子信号的时间间隔，并将时间间隔转化为时间码，直方图电路对TDC电路输出的时间码进行累积计数以绘制出直方图。处理器13根据直方图计算出光子从发射到接收的飞行时间，可以进一步计算出目标物20的距离。作为一非限制性示例，如图2所示，与开启的光源对应的像素包括一个或多个SPAD，一个或多个SPAD连接同一TDC电路和直方图电路，一个或多个SPAD将光子信号输出至TDC电路，TDC电路连接直方图电路，直方图电路连接处理器。可选地，在一些场景下可以按照时序依次启动不同的像素、超像素或合像素，还可以将不同像素、超像素或合像素包括的多个SPAD连接同一个TDC电路和直方图电路。
在一个实施例中，偏振器122为偏振片，偏振片与像素单元121(或像素阵列)间隔设置。例如，偏振片可以包括分子型或微晶型等。
在一个实施例中，偏振器122为液晶偏振光栅，液晶偏振光栅与像素单元121(或像素阵列)间隔设置。
在一个实施例中，偏振器122为具有偏振特性的复合膜层，复合膜层经镀膜工艺而镀敷于像素单元121(或像素阵列)。
在一些实施例中，继续参阅图1所示，采集器12还包括接收光学元件123，光学接收元件123、偏振器122以及像素单元121沿光信号的传播路径依次设置，接收光学元件123用于将被目标物20所反射的光信号成像至像素单元121。
在一些实施例中，继续参阅图1所示，发射器11包括第一光源111和驱动第一光源111的第一驱动器113，第一光源111在第一驱动器113的驱动下并在处理器的控制下按照时序发射具有不同偏振方向的线偏振态的光信号。可选地， 第一光源111是垂直腔面发射激光器(Vertical Cavity Surface Emitting Laser,VCSEL)，为了使VCSEL发射稳定的具有线偏振态的光信号，需对VCSEL进行偏振控制处理获得偏振控制的VCSEL光源。其中的偏振处理包括在VCSEL的出光孔表面生长芯片结构、外腔反馈结构、半导体光栅、表面浮雕结构等。基于偏振控制的VCSEL光源可以发射不同偏振方向的线偏振光。线偏振光投射至目标物20，被目标物20所反射回的反射光信号依然是线偏振光，且偏振方向不会发生变化。在这些实施例中，第一光源111和偏振器122在处理器的控制下同步切换偏振方向，并且第一光源111发射的线偏振光的偏振方向与偏振器122的偏振方向相同。
在其他一些实施例中，继续参阅图1所示，发射器11包括第二光源111、起偏器(图中未示出)和第二驱动器113，起偏器设置于第二光源111的出光方向，起偏器为可调偏振方向的偏振器，第二光源111在第二驱动器113的驱动下并在处理器的控制下发射无偏振态的光信号，起偏器用于将第二光源111产生的无偏振态的光信号调节成具有线偏振态的光信号。第二光源111所发射的无偏振态的光信号经过起偏器后成为线偏振态的光信号，通过起偏器的光信号的偏振方向与偏振器的偏振方向相同，也就是说，起偏器和偏振器在处理器的控制下同步切换偏振方向，并且起偏器的偏振方向与偏振器的偏振方向相同。可选地，起偏器也可以是偏振片，起偏器与第二光源111间隔设置；或者，起偏器也可以是液晶偏振光栅，起偏器与第二光源111间隔设置；或者，起偏器也可以是具有偏振特性的复合膜层，复合膜层经镀膜工艺而镀敷于光源。
作为一非限制性示例，按照时序，在处理器的控制下，起偏器和检偏器同步在两个正交偏振方向上进行切换。例如，在第一时间段，起偏器和检偏器的偏振方向均为水平方向，在第二时间段，起偏器和检偏器的偏振方向均为垂直方向。在这个实现方式中，第一时间段和第二时间段的两个偏振方向正交设置。
进一步地，在一些实施例中，继续参阅图1所示，发射器11还包括发射光学元件112，发射光学元件112用于将线偏振态的光信号投射至目标物20，并 使该光信号于目标物20上形成照明斑点。可选地，发射光学元件112包括但不限于准直镜、衍射光学元件等中的一种或几种的组合。
在一些实施例中，起偏器可以设置于光源111和发射光学元件112之间；或者，可以设置于某两个发射光学元件112之间；或者，可以设置于所有发射光学元件112的出光侧，本申请实施例对起偏器的设置位置不予具体限制。
在一些实现方式中，光源(包括前述的第一光源或第二光源)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。其中，光源可以在处理器的控制下以一定频率(或脉冲周期)向目标物20发射脉冲光束30，脉冲光束30经过发射光学元件112投射到目标物20上形成照明斑点。
在图1所示的实施例中，采集器按照时序对至少两个不同偏振方向的线偏振光分别进行接收，然后在同一个直方图电路中进行累加计数，得到直方图，直方图就有了更高信噪比，可以进一步提升光学测量系统的抗干扰性能，从而提升系统的准确度。
作为前述图1和图2所示实施例的一替代方案，本申请另一实施例提供一种光学测量系统。本实施例中，偏振器不是可调偏振器，采集器的像素前设置多个不可调偏振器，多个偏振器的偏振方向不相同，可以分别用于透过不同偏振方式的线偏振光，该线偏振光是发射器按照时序发射的。在本实施例中，以偏振器为2种，发射器按照时序先后发射偏振方向彼此正交的两种线偏振光作为示例性描述，2种偏振器的偏振方向分别与两种线偏振光的偏振方向相同。应理解，本实施例与前述实施例相同之处，此处不再赘述，请参见前述。
在本实施例中，开启一光源按照时序发射不同偏振方向的两种线偏振光，与开启的光源对应的像素包括多个SPAD，多个SPAD的入光侧并列设置2个偏振器。可选的，2个偏振器的偏振方向正交。
在一个实施例中，如图3A所示，对应同一偏振器的一组SPAD连接同一个TDC电路和直方图电路，对应不同偏振器的两组SPAD，即第一组SPAD和第二组SPAD，各自连接一个TDC电路和直方图电路；两个直方图电路分别连接 加法器，加法器将两个直方图电路生成的直方图相加以得到新的直方图，即融合直方图。可选地，加法器可以连接处理器，处理器根据新的直方图可以计算目标物的距离。
在另一个实施例中，如图3B所示，对应不同偏振器的两组SPAD连接同一个TDC电路和直方图电路。可选地，直方图电路可以连接处理器，处理器根据直方图可以计算目标物的距离。需要说明的是，在图3B所示的实施例中，由于两组SPAD连接同一个TDC电路和直方图电路，还可以不对对应不同偏振器的SPAD进行分组，将两组SPAD作为一个整体看待。在另一个实施例中，如图3C所示，对应不同偏振器的两组SPAD连接不同TDC电路，两个TDC电路连接同一直方图电路。可选地，直方图电路可以连接处理器，处理器根据直方图可以计算目标物的距离。
作为前述图1和图2实施例的另一替代方案，本申请另一实施例提供一种光学测量系统。本实施例中，在发射器的光源前设置多个起偏器，多个起偏器的偏振方向不相同，发射器可以同时发射多个偏振方式的线偏振光。应理解，本实施例与前述实施例相同之处，此处不再赘述，请参见前述。
本实施例提供的光学测量系统包括发射器、采集器、读出电路和处理器。发射器包括由多个光源组成的光源阵列和设置于各光源的入光侧的多个起偏器，多个起偏器的偏振方向不相同。采集器包括多个像素组成的像素阵列和设置于各像素入光侧的多个偏振器。光源与像素一一对应设置，起偏器和偏振器均为可调偏振器，对应的起偏器和偏振器按照时序同步改变偏振方向，其中，上述像素也可以是合像素或者超像素。
在一个实施例中，如图4所示，在VCSEL光源41前并行设置两个起偏器，即第一起偏器421和第二起偏器422。在该VCSEL光源41对应的像素所包括的SPAD前并行设置两个偏振器，即第一偏振器431和第二偏振器432，具体地，以VCSEL光源对应的像素包括两组SPAD为例，一组SPAD包括至少一个SPAD，第一组SPAD441前设置第一偏振器431，第二组SPAD442前设置第二偏振器 432。相互对应的偏振器的偏振方向与起偏器的偏振方向相同，从而使得SPAD可以采集到线偏振态的反射光。第一组SPAD441接收目标物反射回的第一偏振方向的线偏振光并生成的与第一偏振方向对应的第一光子信号，第二组SPAD442接收目标物反射回的第二偏振方向的线偏振光并生成与第二偏振方向对应的第二光子信号。在一个实施例中，两个起偏器的偏振方向正交设置，一个为水平方向，一个为竖直方向；两个偏振器的偏振方向正交设置，一个为水平方向，一个为竖直方向。
进一步地，在图4所示实施例中，第一组SPAD441连接第一TDC电路451和第一直方图电路461，第二组SPAD442连接第二TDC电路452和第二直方图电路462，第一直方图电路461和第二直方图电路462连接加法器47。第一TDC电路451根据第一偏振方向对应的第一光子信号生成第一时间信号，第一直方图电路461根据第一偏振方向对应的第一时间信号生成第一直方图；第二TDC电路452根据第二偏振方向对应的第二光子信号生成第二时间信号，第二直方图电路462根据第二偏振方向对应的第二时间信号生成第二直方图。加法器47将第一直方图电路461生成的第一直方图与第二直方图电路462生成的第二直方图相加，得到第三直方图。在其他一些实施例中，加法器还可以连接处理器，处理器可以根据第三直方图计算目标物的距离。
作为一非限制性示例，第一起偏器421和第一偏振器431的偏振方向均为水平方向，第二起偏器422和第二偏振器432的偏振方向均为竖直方向。开启VCSEL光源41朝向目标物发射光信号并同步开启与VCSEL光源41对应的SPAD采集反射光信号，VCSEL光源41发射的光信号经过第一起偏器421发出偏振方向为水平方向的线偏振光，经过第二起偏器422发出偏振方向为竖直方向的线偏振光；经过目标物反射后，偏振方向为水平方向的线偏振光透过第一偏振器431后被第一组SPAD441采集并生成第一光子信号，偏振方向为竖直方向的线偏振光透过第二偏振器432后被第二组SPAD442采集并生成第二光子信号。
需要说明的是，在图4所示示例中，为了方便描述，以VCSEL光源对应两组SPAD进行描述，应理解，示例性描述不能解释为对本申请的具体限制。在其他实施例中，当VCSEL光源发射的光通过三种不同偏振方向的线偏振光，即起偏器包括三个不同偏振方向时，VCSEL光源对应的SPAD前设置的偏振器有三个，并且三个偏振器的偏振方向与三个起偏器的偏振方向一一对应相同。
还需要说明的是，在图4所示示例中，仅示出了同步开启一个VCSEL光源发射光信号，以及开启与该一个VCSEL光源对应的一个像素所包括的SPAD进行光子接收的情形。应理解，本实施例可以拓展到其他情形，例如同步开启多个或一组VCSEL光源形成线状斑点光束以及该多个或一组VCSEL光源对应的像素所包括的SPAD的情形等。更一般地，VCSEL光源阵列包括多个VCSEL光源，SPAD阵列包括多个SPAD，一个区域的VCSEL光源与一个区域的SPAD一一对应，开启任一个区域的VCSEL光源发射光信号时，同步开启与该区域一一对应的某一区域的SPAD采集反射的光信号。
在图4所示的实施例中，采集器对两个不同偏振方向的线偏振光各自进行接收，然后加法器把针对不同偏振方向分别计数的直方图加起来，得到新的直方图，新的直方图就有了2倍信噪比的分集的性能，可以进一步提升光学测量系统的抗干扰性能，从而提升系统的准确度。
在另一个实施例中，作为图4所示实施例的一替代实施例，如图5所示，读出电路包括TDC电路45和直方图电路46。第一组SPAD441和第二组SPAD442对应连接同一TDC电路45和直方图电路46。TDC电路45用于接收第一光子信号和第二光子信号，并计算各光子信号的时间间隔，并将时间间隔转化对应的时间码。直方图电路46对TDC电路45输出的时间码进行计数以绘制出直方图。在一些实施例中，直方图电路46连接处理器，处理器可以根据直方图计算出光子从发射到接收的飞行时间，可以进一步计算出目标物的距离。
需要说明的是，在图5所示的实施例中，由于两组SPAD，即第一组SPAD441和第二组SPAD442连接同一个TDC电路和直方图电路，还可以不对对应不同 偏振器的SPAD进行分组，将第一组SPAD441和第二组SPAD442作为一个整体看待。
在另一个实施例中，作为图4所示实施例的另一替代实施例，如图6所示，第一组SPAD441对应连接同一第一TDC电路451，第二组SPAD442对应连接同一第二TDC电路452，第一TDC电路451和第二TDC电路452连接同一直方图电路46。第一TDC电路451接收第一光子信号，并计算第一光子信号的第一时间间隔，并将第一时间间隔转化对应的时间码。第二TDC电路452接收第二光子信号，并计算第二光子信号的第二时间间隔，并将第二时间间隔转化对应的时间码。直方图电路46对第一TDC电路451和第二TDC电路452输出的时间码进行累积计数以绘制出直方图。在一些实施例中，直方图电路46可以连接处理器，处理器可以根据直方图计算出光子从发射到接收的飞行时间，可以进一步计算出目标物的距离。
以上仅为本申请的较佳实施例而已，并不用以限制本申请，凡在本申请的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本申请的保护范围之内。

Claims (10)

  1. 一种光学测量系统，其特征在于，包括：
    发射器，配置为向目标物发射具有至少两个不同偏振方向的线偏振光；
    采集器，配置为分别接收被所述目标物反射回的至少两个不同偏振方向的线偏振光，并生成各偏振方向对应的光子信号；
    读出电路，配置为接收所述各偏振方向对应的光子信号并进行处理生成融合直方图；
    处理器，配置为同步所述发射器和所述采集器，并根据所述融合直方图计算所述目标物的距离。
  2. 如权利要求1所述的光学测量系统，其特征在于，所述读出电路包括TDC电路阵列、直方图电路阵列和加法器，所述TDC电路阵列配置为根据所述各偏振方向对应的光子信号生成各偏振方向对应的时间信号，所述直方图电路阵列对应配置为根据所述各偏振方向对应的时间信号生成各偏振方向对应的直方图，所述加法器配置为将所述各偏振方向对应的直方图进行相加得到所述融合直方图。
  3. 如权利要求1所述的光学测量系统，其特征在于，所述读出电路包括至少一个TDC电路和直方图电路，所述至少一个TDC电路配置为根据所述各偏振方向对应的光子信号生成各偏振方向对应的时间信号，所述直方图电路配置为对所述各偏振方向对应的时间信号进行累计以生成所述融合直方图。
  4. 如权利要求1所述的光学测量系统，其特征在于，所述发射器包括多个光源组成的光源阵列，至少一个所述光源在所述处理器的控制下按时序发射至少两个不同偏振方向的所述线偏振光；
    所述采集器包括多个像素组成的像素阵列和设置于各所述像素入光侧的偏振器，所述至少一个所述光源与至少一个所述像素一一对应设置；
    在所述处理器的控制下，所述至少一个所述光源对应的所述像素入光侧的 所述偏振器与所述线偏振光同步改变偏振方向。
  5. 如权利要求1所述的光学测量系统，其特征在于，所述发射器包括多个光源组成的光源阵列和设置于所述光源阵列出光侧的起偏器；所述采集器包括多个像素组成的像素阵列和设置于所述像素阵列入光侧的偏振器，所述起偏器和所述偏振器均为可调偏振器，所述起偏器和所述偏振器按照时序同步改变偏振方向。
  6. 如权利要求1所述的光学测量系统，其特征在于，所述发射器包括多个光源组成的光源阵列和设置于各所述光源出光侧的多个起偏器，各所述起偏器的偏振方向不同；所述采集器包括多个像素组成的像素阵列和设置于各所述像素入光侧的多个偏振器，各偏振器的偏振方向不同，所述光源与所述像素一一对应设置，一一对应的多个所述起偏器和多个所述偏振器的偏振方向对应相同。
  7. 如权利要求1至6任一项所述的光学测量系统，其特征在于，所述至少两个不同偏振方向包括两个正交的偏振方向。
  8. 如权利要求4至6任一项所述的光学测量系统，其特征在于，所述像素包括至少一个SPAD，所述光源包括VCSEL光源。
  9. 如权利要求6所述的光学测量系统，其特征在于，所述偏振器为偏振片、液晶偏振光栅或具有偏振特性的复合膜层。
  10. 如权利要求3至5任一项所述的光学测量系统，其特征在于，
    所述发射器还包括发射光学元件，所述发射光学元件用于将所述线偏振光投射至所述目标物，并使所述线偏振光于所述目标物上形成照明斑点；
    所述采集器还包括接收光学元件，所述光学接收元件、所述偏振器以及所述像素阵列沿所述线偏振光的传播路径依次设置，所述接收光学元件用于将被所述目标物所反射的所述线偏振光成像至所述像素阵列。
PCT/CN2022/080512 2021-11-23 2022-03-13 一种光学测量系统 WO2023092895A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202122887094.7 2021-11-23
CN202122887094.7U CN216622678U (zh) 2021-11-23 2021-11-23 一种光学测量系统

Publications (1)

Publication Number Publication Date
WO2023092895A1 true WO2023092895A1 (zh) 2023-06-01

Family

ID=81697399

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/080512 WO2023092895A1 (zh) 2021-11-23 2022-03-13 一种光学测量系统

Country Status (2)

Country Link
CN (1) CN216622678U (zh)
WO (1) WO2023092895A1 (zh)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN211426796U (zh) * 2019-10-18 2020-09-04 深圳奥锐达科技有限公司 一种离轴扫描距离测量系统
CN111856433A (zh) * 2020-07-25 2020-10-30 深圳奥锐达科技有限公司 一种距离测量系统及测量方法
CN111880189A (zh) * 2020-08-12 2020-11-03 中国海洋大学 连续光距离选通激光雷达
US20210055389A1 (en) * 2019-08-21 2021-02-25 GM Global Technology Operations LLC System and method for time of flight measurement based upon time modulated polarization state illumination
CN113156458A (zh) * 2020-01-03 2021-07-23 华为技术有限公司 一种tof深度传感模组和图像生成方法
CN214795204U (zh) * 2021-02-05 2021-11-19 奥比中光科技集团股份有限公司 一种激光测量系统

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210055389A1 (en) * 2019-08-21 2021-02-25 GM Global Technology Operations LLC System and method for time of flight measurement based upon time modulated polarization state illumination
CN211426796U (zh) * 2019-10-18 2020-09-04 深圳奥锐达科技有限公司 一种离轴扫描距离测量系统
CN113156458A (zh) * 2020-01-03 2021-07-23 华为技术有限公司 一种tof深度传感模组和图像生成方法
CN111856433A (zh) * 2020-07-25 2020-10-30 深圳奥锐达科技有限公司 一种距离测量系统及测量方法
CN111880189A (zh) * 2020-08-12 2020-11-03 中国海洋大学 连续光距离选通激光雷达
CN214795204U (zh) * 2021-02-05 2021-11-19 奥比中光科技集团股份有限公司 一种激光测量系统

Also Published As

Publication number Publication date
CN216622678U (zh) 2022-05-27

Similar Documents

Publication Publication Date Title
US12123976B2 (en) Laser scanner
US20210181317A1 (en) Time-of-flight-based distance measurement system and method
WO2021072802A1 (zh) 一种距离测量系统及方法
US8610043B2 (en) Proximity sensor having an array of single photon avalanche diodes and circuitry for switching off illumination source and associated method, computer readable medium and firmware
WO2021120403A1 (zh) 一种深度测量装置及测量方法
CN111722241B (zh) 一种多线扫描距离测量系统、方法及电子设备
CN211014630U (zh) 激光雷达设备及机动车系统
CN211014629U (zh) 一种激光雷达装置
WO2022017366A1 (zh) 一种深度成像方法及深度成像系统
US20220277467A1 (en) Tof-based depth measuring device and method and electronic equipment
US10422862B2 (en) LiDAR apparatus
WO2022011974A1 (zh) 一种距离测量系统、方法及计算机可读存储介质
WO2022082985A1 (zh) 一种多线扫描距离测量系统
US20180164410A1 (en) LiDAR Apparatus
WO2020237764A1 (zh) 激光雷达装置
CN111812663A (zh) 深度测量模组及系统
WO2020221188A1 (zh) 基于同步ToF离散点云的3D成像装置及电子设备
JPWO2018211831A1 (ja) 光検出器および携帯型電子機器
WO2022083198A1 (zh) 一种多线扫描距离测量系统
US20210103034A1 (en) Dynamic beam splitter for direct time of flight distance measurements
CN114488173A (zh) 一种基于飞行时间的距离探测方法和系统
CN213903798U (zh) 一种具有双重发光模式的距离测量系统
WO2023092895A1 (zh) 一种光学测量系统
CN214795204U (zh) 一种激光测量系统
WO2020259193A1 (zh) 激光探测的装置、方法及系统

Legal Events

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

Ref document number: 22896997

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE