Distance measurement system, method and computer-readable storage medium

Abstract

The present application is applicable to the field of time-of-flight technology, and provides a distance measurement system, method and computer-readable storage medium, including an emitter, a collector and a processing circuit connected to the emitter and the collector; wherein the emitter is used to emit a pulse light beam to a target; the collector includes a pixel unit and a grating, the pixel unit includes multiple sensing areas, the grating and the pixel unit are separated by a preset distance, the pulse light beam reflected by the target is diffracted by the grating to form multiple light spots on the surface of the pixel unit, the sensing area is used to collect photons in the light spots and output photon signals; the processing circuit is used to calculate multiple first flight times of the pulse light beam based on the multiple photon signals output by the pixel unit, and curve fitting is performed on the multiple first flight times to obtain the second flight time of the pulse light beam, which can effectively improve the accuracy of the distance measured based on the second flight time.

Description

Technical Field

[0001] The present application belongs to the field of time of flight (TOF) technology, and in particular relates to a distance measurement system, method, and computer-readable storage medium. Background Art

[0002] Distance measurement systems based on time-of-flight technology have been widely used in consumer electronics, unmanned aerial vehicles, virtual reality, augmented reality, and other fields. These systems typically consist of a transmitter and a collector. The transmitter emits a pulsed light beam to illuminate a target, and the collector receives the pulsed light beam reflected by the target. The distance between the target and the distance measurement system is calculated by calculating the time it takes for the pulse beam to be emitted and received. However, existing distance measurement systems are subject to interference from ambient light noise, signal light shot noise, and collector noise, resulting in certain errors in the measured distance. Consequently, the distance measured at different times in the same scene can fluctuate significantly. Summary of the Invention

[0003] In view of this, embodiments of the present application provide a distance measurement system, method, and computer-readable storage medium to address the problem that existing distance measurement systems are subject to interference from ambient light noise, signal light shot noise, collector noise, etc., resulting in the measured distance containing certain errors and large fluctuations in the distance measured at different times in the same scenario.

[0004] A first aspect of an embodiment of the present application provides a distance measurement system, comprising a transmitter, a collector, and a processing circuit connected to the transmitter and the collector;

[0005] The transmitter is used to transmit a pulsed light beam toward a target;

[0006] The collector includes a pixel unit and a grating, wherein the pixel unit includes multiple sensing areas, the grating is separated from the pixel unit by a preset distance, and the pulsed light beam reflected by the target forms multiple light spots on the surface of the pixel unit after diffraction by the grating. The sensing areas are used to collect photons in the light spots and output photon signals;

[0007] The processing circuit is used to calculate multiple first flight times of the pulse light beam according to the multiple photon signals output by the pixel unit, and perform curve fitting on the multiple first flight times to obtain the second flight time of the pulse light beam.

[0008] A second aspect of the embodiments of the present application provides a distance measurement method implemented by the distance measurement system provided in the first embodiment of the present application, comprising the following steps implemented by a processing circuit:

[0009] Control the transmitter to emit a pulse beam toward the target;

[0010] Controlling the pixel unit to collect a plurality of light spots formed on the surface of the pixel unit after the pulse light beam reflected by the target is diffracted by the grating;

[0011] A plurality of first flight times of the pulse light beam are calculated based on a plurality of photon signals output by the pixel unit, and a second flight time of the pulse light beam is obtained by performing curve fitting on the plurality of first flight times.

[0012] A third aspect of the embodiments of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program. When the computer program is executed by a processing circuit, the steps of the distance measurement method described in the second aspect of the embodiments of the present application are implemented.

[0013] The first aspect of an embodiment of the present application provides a distance measurement system, including an emitter, a collector, and a processing circuit connected to the emitter and the collector; the emitter is used to emit a pulse light beam to a target; the collector includes a pixel unit and a grating, the pixel unit includes multiple sensing areas, the grating and the pixel unit are separated by a preset distance, the pulse light beam reflected by the target is diffracted by the grating to form multiple light spots on the surface of the pixel unit, the sensing area is used to collect photons in the light spots and output photon signals; the processing circuit is used to calculate multiple first flight times of the pulse light beam based on the multiple photon signals output by the pixel unit, and curve fit the multiple first flight times to obtain the second flight time of the pulse light beam. By dispersing the pulse light beam into multiple independent light spots and projecting them to different sensing areas for independent, multiple, and simultaneous collection, multiple photon signals are obtained and multiple first flight times are calculated, and then curve fitting is performed on the multiple first flight times to obtain the second flight time, the accuracy of the distance measured based on the second flight time can be effectively improved.

[0014] It can be understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] Figure 1 is a structural diagram of a distance measurement system provided in an embodiment of the present application;

[0017] Figure 2This is a first schematic diagram of a pixel unit and a light spot provided in an embodiment of the present application;

[0018] Figure 3 This is a second schematic diagram of a pixel unit and a light spot provided in an embodiment of the present application;

[0019] Figure 4 This is a schematic diagram of the structure of the collector provided in an embodiment of the present application;

[0020] Figure 5 Schematic diagram of the structure of the pixel unit and processing circuit provided in the embodiment of the present application. DETAILED DESCRIPTION

[0021] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known devices, systems, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0022] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or arrays, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, arrays and / or combinations thereof.

[0023] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0024] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present invention. Thus, the phrase "in one embodiment" appearing in various places in this specification does not necessarily refer to the same embodiment, but rather means "one or more, but not all, embodiments," unless otherwise specifically stated. The term "including" and variations thereof mean "including but not limited to," unless otherwise specifically stated.

[0025] like Figure 1 As shown, an embodiment of the present application provides a distance measurement system 100, comprising a transmitter 1, a collector 2, and a processing circuit 3 connected to the transmitter 1 and the collector 2;

[0026] Emitter 1, for emitting a pulsed light beam 300 toward a target 200;

[0027] Collector 2 includes a pixel unit 21 and a grating 22. The pixel unit 21 includes multiple sensing areas. The grating 22 is separated from the pixel unit 21 by a preset distance. The pulsed light beam 400 reflected by the target 200 is diffracted by the grating to form multiple light spots on the surface of the pixel unit 21. The sensing areas are used to collect photons in the light spots and output photon signals.

[0028] The processing circuit is used to calculate multiple first flight times of the pulse light beam according to the multiple photon signals output by the pixel unit 21, and perform curve fitting on the multiple first flight times to obtain the second flight time of the pulse light beam.

[0029] In application, the target can be any object in free space. At least part of the pulse light beam emitted by the transmitter to the target is reflected by the target back to the collector, so that the pulse light beam reflected by the target forms multiple light spots on the surface of the pixel unit after diffraction by the grating, so that at least part of the sensing area in the pixel unit can independently, multiple times and simultaneously collect the pulse light beam reflected by the target and perform photoelectric conversion to obtain corresponding photon signals, and then output the photon signals to the processing circuit. The processing circuit calculates multiple first flight times of the pulse light beam based on the multiple photon signals output by the pixel unit, and then performs curve fitting on the multiple first flight times to obtain the second flight time of the pulse light beam. Based on the second flight time, the distance between the target and the distance measurement system can be calculated. The processing circuit is used to synchronously send a trigger signal to the transmitter and the collector to synchronously trigger the transmitter to emit the pulse light beam and the collector to collect the multiple light spots formed on the surface of the pixel unit after the pulse light beam reflected by the target is diffracted by the grating. The trigger signal can be a clock signal. The calculation formula for the distance between the target and the distance measurement system is as follows:

[0030]

[0031] Where D is the distance between the target and the distance measurement system, c is the speed of light, Indicates the second flight time.

[0032] In an application, the transmitter includes a light source unit, which includes at least one light source. The light source can be a light emitting diode (LED), a laser diode (LD), an edge emitting laser (EEL), a vertical cavity surface emitting laser (VCSEL), etc. The number of light sources included in the light source unit can be set according to actual needs. The light source unit can be a one-dimensional or two-dimensional light source array composed of at least two light sources. The light source array can be a vertical cavity surface emitting laser array chip formed by generating multiple vertical cavity surface emitting lasers on a single semiconductor substrate. The arrangement of the light sources in the light source array can be regular or irregular. The pulsed light beam emitted by the light source can be visible light, infrared light, ultraviolet light, etc. The transmitter can emit a pulsed light beam of only one wavelength toward the target, or it can emit pulsed light beams of at least two wavelengths toward the target. The number of wavelengths of the pulsed light beam can be set according to actual needs. When the transmitter can emit pulsed light beams of at least two wavelengths toward the target, the light source unit includes at least two light sources, and the number of light sources for emitting pulsed light beams of each wavelength is at least one.

[0033] In application, the pixel unit includes multiple sensing areas. The pixel unit can be a pixel array composed of multiple sensing areas, and the sensing area can be a single photon avalanche photodiode (SPAD). The single photon avalanche photodiode can respond to an incident single photon and output a signal indicating the time when the photon reaches the single photon avalanche photodiode, and uses a method such as time-correlated single photon counting (TCSPC) to realize the collection of weak light signals and the calculation of the first flight time. Each sensing area has the function of collecting photons in the light spot projected onto its surface and outputting a photon signal.

[0034] In application, a preset distance is set between the grating and the pixel unit. The preset distance and the diffraction order of the grating can be set according to actual needs. The number of light spots of each wavelength of the pulse light beam reflected by the target after diffraction by the grating and projected onto the pixel unit is equal to 2 times the diffraction order of the grating plus 1. Preferably, the diffraction order of the grating is selected to be 1, then the number of light spots of each wavelength of the pulse light beam reflected by the target after diffraction by the grating and projected onto the pixel unit is 1×2+1=3, that is, the light spots of each wavelength of the pulse light beam reflected by the target after diffraction by the beam projected onto the pixel unit include 0-order light spots, -1-order light spots and 1-order light spots. Since the light energy of the -1-order light spots and the 1-order light spots is the strongest, as the diffraction order increases, the light energy of the diffraction spots gradually decreases. Therefore, the light spots of other orders can be ignored. The light spots of the pulse light beams of all wavelengths reflected by the target after diffraction by the grating and projected onto the pixel unit are all located in the same row or column.

[0035] In one embodiment, the transmitter is configured to transmit a pulsed light beam of one wavelength toward a target;

[0036] A pulsed beam of a wavelength reflected by the target is diffracted by the grating to form x light spots on the surface of the pixel unit;

[0037] Here, x is equal to 2 times the diffraction order m of the grating plus 1.

[0038] Figure 2 The first schematic diagram of the pixel unit and the light spot is shown as an example; wherein the pixel unit 21 is a pixel array consisting of 8×8 sensing areas, and a pulse light beam of a single wavelength is diffracted by the grating to form three light spots on the surface of the pixel unit 21, namely, the 0-order light spot, the -1-order light spot and the 1-order light spot.

[0039] In one embodiment, the transmitter is configured to transmit a pulsed light beam of y wavelengths toward a target;

[0040] The pulsed light beams of y wavelengths reflected by the target are diffracted by the grating to form a total of k light spots on the surface of the pixel unit;

[0041] Here, k is greater than or equal to 2 times the diffraction order m of the grating plus 1, and k is less than or equal to 2y times the diffraction order m of the grating plus 1.

[0042] In application, due to the size limitation of the system, when the transmitter emits a pulsed light beam of at least two wavelengths to the target, the light spots projected onto the pixel unit may overlap with the light spots of orders other than order 0, so that the total number of light spots projected onto the pixel unit by the pulsed light beams of at least two wavelengths after diffraction by the grating is greater than or equal to 2 times the highest diffraction order m of the grating plus 1, and less than or equal to 2y times the highest diffraction order m of the grating plus 1, wherein the 0th order light spots of the pulsed light beams of each wavelength after diffraction by the grating projected onto the pixel unit overlap.

[0043] Figure 3 A second schematic diagram of a pixel unit and a light spot is shown as an example; wherein the pixel unit 21 is a pixel array consisting of 8×8 sensing areas, and the pulse light beams of two wavelengths are diffracted by the grating to form five light spots on the surface of the pixel unit 21, namely, the 0th order light spot, -1th order light spot and 1st order light spot corresponding to the pulse light beam of the first wavelength, and the 0th order light spot, -1th order light spot and 1st order light spot corresponding to the pulse light beam of the second wavelength, which overlap with the 0th order light spot corresponding to the pulse light beams of the two wavelengths, and different filling patterns are used to distinguish and display the light spots corresponding to the pulse light beams of different wavelengths.

[0044] In applications, in order to avoid the overlap of light spots of orders other than order 0 when pulse beams of at least two wavelengths are projected onto the light spots of the pixel unit after being diffracted by the grating, the spacing distance between the grating and the pixel unit needs to be reasonably set.

[0045] In one embodiment, two pulsed light beams with wavelengths λ1 and λ2 are projected onto the pixel unit after diffraction by the grating to form a 0-order light spot, a -1-order light spot, and a 1-order light spot corresponding to each wavelength of the pulsed light beam, respectively, and overlap with the 0-order light spots corresponding to the two wavelengths of the pulsed light beams, forming a total of five light spots. In order to prevent the +1-order or -1-order light spots other than the 0-order from overlapping, the preset distance needs to satisfy the following relationship:

[0046]

[0047] Wherein, h represents the preset distance, r(λ1) represents the radius of the -1 order or 1 order light spot formed on the surface of the pixel unit after the pulse light beam with a wavelength of λ1 is diffracted by the grating, r(λ2) represents the radius of the -1 order or 1 order light spot formed on the surface of the pixel unit after the pulse light beam with a wavelength of λ2 is diffracted by the grating, θ1 represents the diffraction angle of the -1 order or 1 order light spot formed on the surface of the pixel unit after the pulse light beam with a wavelength of λ1 is diffracted by the grating, and θ2 represents the diffraction angle of the -1 order or 1 order light spot formed on the surface of the pixel unit after the pulse light beam with a wavelength of λ2 is diffracted by the grating.

[0048] In an application, when the transmitter emits pulsed light beams of two wavelengths toward a target, the preset distance may be set in a manner including, but not limited to, the above-mentioned relationship. For situations where the transmitter emits pulsed light beams of two or more wavelengths toward a target, the preset distance may also be set by: transmitting pulsed light beams of y wavelengths toward the target, then continuously adjusting the spacing between the grating and the pixel unit, and obtaining the number of light spots formed on the surface of the pixel unit after the pulsed light beams of y wavelengths reflected by the target are diffracted by the grating. When the number of light spots is equal to 2y times the diffraction order m of the grating plus 1, it can be determined that the light spots of orders other than order 0 do not overlap. The y wavelengths and the spacing between the grating and the pixel unit at this time are calibrated, and a correlation between the y wavelengths and the spacing distances is established and recorded. This facilitates subsequent distance measurement by obtaining the associated spacing distance based on the wavelength of the pulsed light beam emitted by the transmitter. The preset distance is set to be greater than or equal to the spacing distance, so that the light spots of orders other than order 0 formed on the surface of the pixel unit after the pulsed light beams of y wavelengths reflected by the target are diffracted by the grating do not overlap.

[0049] Figure 4 The structural diagram of the collector is shown as an example; wherein, the pixel unit 21 and the grating 22 are separated by a preset distance h, and the diffraction angle of the -1 order or 1 order light spot formed on the surface of the pixel unit after the pulse light beam with a wavelength of λ1 is diffracted by the grating is θ1, and the diffraction angle of the -1 order or 1 order light spot formed on the surface of the pixel unit after the pulse light beam with a wavelength of λ2 is diffracted by the grating is θ2, and different dotted arrows represent diffracted light beams corresponding to pulse light beams of different wavelengths.

[0050] In one embodiment, the pulsed light beam reflected by the target forms a plurality of light spots on the surface of n sensing areas among the plurality of sensing areas after being diffracted by the grating;

[0051] a processing circuit, configured to calculate n first flight times of the pulsed light beam based on n photon signals outputted by the n sensing regions, and perform curve fitting on the n first flight times to obtain a second flight time of the pulsed light beam;

[0052] Here, n is less than or equal to the total number of the plurality of sensing regions.

[0053] In applications, the pulsed light beam reflected by the target may form multiple light spots on the surface of only part of the sensing area of the pixel unit after diffraction by the grating. Therefore, when calculating the first time of flight, the processing circuit can calculate the first time of flight based on the photon signal output by only the part of the sensing area covered by the light spot, and then perform curve fitting based on these first time of flight to obtain the second time of flight. Specifically, the position of the sensing area where the light spot of the pixel unit is located after the pulsed light beam of different wavelengths is projected by the grating can be obtained in advance, and the association between the pulsed light beam of different wavelengths and the sensing area at the corresponding position can be established and recorded. When a pulsed light beam of any wavelength is subsequently emitted to the target by the transmitter for ranging, only the sensing area associated with the pulsed light beam of that wavelength can be triggered to collect the light spot and output the photon signal. Since each sensing area may collect ambient light, this method can reduce the ambient light received by the pixel unit, and can reduce the interference of ambient light noise to a certain extent, thereby reducing the ranging error and improving the ranging accuracy.

[0054] In one embodiment, the expression for curve fitting of n first flight times is as follows:

[0055]

[0056] Wherein, i=1, 2, ..., n, i represents the i-th sensing area among n sensing areas, represents the second flight time of the pulse beam, t i represents the first flight time of the pulse light beam calculated according to the photon signal output by the i-th sensing area.

[0057] In one embodiment, when hour,

[0058] In application, the curve fitting method can specifically adopt the least square method. It is equivalent to taking the average value of the n first flight times of the pulse beam calculated based on the photon signals output by n sensing areas, which belongs to the curve fitting using the least squares method and letting The special case results obtained when .

[0059] In applications, the processing circuit includes a time-to-digital converter (TDC) circuit and a histogram circuit connected to the pixel unit. It may also include devices such as a signal amplifier and an analog-to-digital converter (ADC). These devices can be integrated with the pixel unit or used as part of the processing circuit. The TDC circuit is used to calculate the first flight time of the pulse light beam, that is, the time difference between the reception time and the transmission time, based on the reception time of the received photon signal and the transmission time of the pulse light beam emitted by the transmitter to the target. The TDC circuit converts the first flight time into a time code and stores it in the histogram circuit connected to it. The time code can be a temperature code or a binary code. The histogram circuit is used to plot the stored time code into a histogram that can represent the waveform of the pulse light beam reflected by the target. The processing circuit may be a central processing unit (CPU), other general-purpose processors, system-on-a-chip (SOC), digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware arrays, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0060] In one embodiment, the processing circuit includes a plurality of TDC circuits and a plurality of histogram circuits, each sensing region is connected to one of the TDC circuits, and each TDC circuit is connected to one of the histogram circuits.

[0061] In applications, the processing circuit can include the same number of TDC circuits and histogram circuits as sensing areas. Since the light spots projected onto the pixel elements by pulsed light beams of all wavelengths reflected by the target after diffraction by the grating are all located in the same row or column, each column or row of sensing areas can be connected to a TDC circuit, and each TDC circuit can be connected to a histogram circuit. This reduces the number of TDC circuits and histogram circuits, thereby simplifying the coefficient structure. Specifically, when the light spots are located in the same row, each column of sensing areas is connected to a TDC circuit; when the light spots are located in the same column, each row of sensing areas is connected to a TDC circuit. All TDC circuits included in the processing circuit can form an array circuit, and all histogram circuits included in the processing circuit can also form an array circuit. The time resolution of the TDC circuit affects the measurement accuracy of the distance measurement system. The more bits of the time code output by the TDC circuit, the higher the storage capacity required by the connected histogram circuit. To reduce data storage capacity, minimize storage space consumption of the histogram circuit, and save costs, it is necessary to appropriately set the time width and time resolution of each TDC circuit.

[0062] Figure 5 The structural schematic diagram of the pixel unit and the processing circuit is shown as an example; wherein the pixel unit 21 is a pixel array consisting of 8×8 sensing areas, and the three light spots projected onto the pixel unit 21 after the pulse light beam of a single wavelength is diffracted by the grating are located in the same column, each row of sensing areas is connected to a TDC circuit 31, and each TDC circuit 31 is connected to a histogram circuit 32.

[0063] The present application also provides a distance measurement method implemented by the distance measurement system provided in the above embodiment, including the following steps implemented by a processing circuit:

[0064] Control the transmitter to emit a pulse beam toward the target;

[0065] Controlling the pixel unit to collect a plurality of light spots formed on the surface of the pixel unit after the pulse light beam reflected by the target is diffracted by the grating;

[0066] A plurality of first flight times of the pulse light beam are calculated based on a plurality of photon signals output by the pixel unit, and a second flight time of the pulse light beam is obtained by performing curve fitting on the plurality of first flight times.

[0067] In application, the distance measurement method may be performed by the processing circuit when running a computer program stored in the processing circuit or in a memory.

[0068] In applications, in some embodiments, the memory can be an internal storage unit of the processing circuit, such as the memory of the processing circuit. In other embodiments, the memory can also be an external storage device of the processing circuit, such as a plug-in hard disk equipped on the system, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. Furthermore, the memory can also include both the internal storage unit of the processing circuit and an external storage device. The memory is used to store the operating system, application programs, boot loaders, data, and other programs, such as the program code of computer programs. The memory can also be used to temporarily store data that has been output or is about to be output.

[0069] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processing circuit, the steps in the above-mentioned distance measurement method embodiment are implemented.

[0070] An embodiment of the present application provides a computer program product. When the computer program product is run on a processing circuit, the processing circuit is caused to execute the steps in the above-mentioned distance measurement method embodiment.

[0071] The distance measurement system provided by the embodiment of the present application includes an emitter, a collector, and a processing circuit connected to the emitter and the collector; the emitter is used to emit a pulse light beam to a target; the collector includes a pixel unit and a grating, the pixel unit includes multiple sensing areas, the grating and the pixel unit are separated by a preset distance, the pulse light beam reflected by the target is diffracted by the grating to form multiple light spots on the surface of the pixel unit, the sensing area is used to collect photons in the light spots and output photon signals; the processing circuit is used to calculate multiple first flight times of the pulse light beam based on the multiple photon signals output by the pixel unit, and curve fit the multiple first flight times to obtain the second flight time of the pulse light beam. By dispersing the pulse light beam into multiple independent light spots and projecting them to different sensing areas for independent, multiple, and simultaneous collection, multiple photon signals are obtained and multiple first flight times are calculated, and then curve fitting is performed on the multiple first flight times to obtain the second flight time, the accuracy of the distance measured based on the second flight time can be effectively improved.

[0072] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0073] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0074] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A distance measurement system, characterized in that: It includes a transmitter, a collector, and a processing circuit connected to the transmitter and the collector; The transmitter is used to transmit a pulsed light beam toward a target; The collector includes a pixel unit and a grating, wherein the pixel unit includes multiple sensing areas, the grating is separated from the pixel unit by a preset distance, and the pulsed light beam reflected by the target forms multiple light spots on the surface of the pixel unit after diffraction by the grating. The sensing areas are used to collect photons in the light spots and output photon signals; a processing circuit configured to pre-acquire positions of sensing regions where light spots of pulsed light beams of different wavelengths are projected onto the pixel units after being diffracted by the grating, establish and record associations between the pulsed light beams of different wavelengths and the sensing regions at corresponding positions, trigger only the sensing regions associated with the pulsed light beam of any wavelength to collect light spots and output photon signals when triggering the emitter to emit a pulsed light beam of any wavelength toward a target, calculate multiple first flight times of the pulsed light beam based on the multiple photon signals output by the pixel units, and perform curve fitting on the multiple first flight times to obtain a second flight time of the pulsed light beam; Wherein, when the transmitter emits a pulsed light beam of y wavelengths toward the target, the pulsed light beam of y wavelengths reflected by the target forms a total of k light spots on the surface of the pixel unit after being diffracted by the grating; k is greater than or equal to 2 times the diffraction order m of the grating plus 1, and k is less than or equal to 2y times the diffraction order m of the grating plus 1; the preset distance is set by continuously adjusting the spacing distance between the grating and the pixel unit, and obtaining the number of light spots formed on the surface of the pixel unit after the pulsed light beam of y wavelengths reflected by the target is diffracted by the grating, and when the number of light spots is equal to 2y times the diffraction order m of the grating plus 1, calibrating the y wavelengths and the spacing distance between the grating and the pixel unit, establishing and recording an association between the y wavelengths and the spacing distance, and setting the preset distance to be greater than or equal to the spacing distance; Alternatively, when the transmitter emits pulsed light beams of two wavelengths toward the target, the pulsed light beams of the two wavelengths reflected by the target form a total of five light spots on the surface of the pixel unit after diffraction by the grating; the five light spots include a 0-order light spot, a -1-order light spot, and a 1-order light spot corresponding to the pulsed light beams of each wavelength, overlap with the 0-order light spot corresponding to the two wavelengths of the pulsed light beams, and the -1-order light spot and the 1-order light spot do not overlap, and the preset distance satisfies the following relationship: Wherein, h represents the preset distance, r(λ1) represents the radius of the -1 order or 1 order light spot formed on the surface of the pixel unit after the pulse light beam with a wavelength of λ1 is diffracted by the grating, r(λ2) represents the radius of the -1 order or 1 order light spot formed on the surface of the pixel unit after the pulse light beam with a wavelength of λ2 is diffracted by the grating, θ1 represents the diffraction angle of the -1 order or 1 order light spot formed on the surface of the pixel unit after the pulse light beam with a wavelength of λ1 is diffracted by the grating, and θ2 represents the diffraction angle of the -1 order or 1 order light spot formed on the surface of the pixel unit after the pulse light beam with a wavelength of λ2 is diffracted by the grating.

2. The distance measurement system according to claim 1, wherein: When the emitter emits a pulse light beam of a wavelength toward the target, the pulse light beam of a wavelength reflected by the target forms x light spots on the surface of the pixel unit after being diffracted by the grating; Here, x is equal to 2 times the diffraction order m of the grating plus 1.

3. The distance measurement system according to claim 1 or 2, characterized in that The pulsed light beam reflected by the target forms a plurality of light spots on the surfaces of n sensing areas among the plurality of sensing areas after being diffracted by the grating; The processing circuit is configured to calculate n first flight times of the pulse light beam according to the n photon signals output by the n sensing areas, and perform curve fitting on the n first flight times to obtain a second flight time of the pulse light beam; The n is less than or equal to the total number of the plurality of sensing areas.

4. The distance measurement system according to claim 3, wherein: The processing circuit includes a plurality of TDC circuits and a plurality of histogram circuits, each of the sensing regions is connected to one of the TDC circuits, and each of the TDC circuits is connected to one of the histogram circuits.

5. The distance measurement system according to claim 3, wherein: The expression for curve fitting of the n first flight times is as follows: Wherein, i=1, 2, ..., n, i represents the i-th sensing area among the n sensing areas, represents the second flight time of the pulsed beam, t i represents the first flight time of the pulse light beam calculated according to the photon signal output by the i-th sensing area.

6. The distance measurement system according to claim 4, wherein: when hour, 7. A distance measurement method implemented based on the distance measurement system according to any one of claims 1 to 6, characterized in that: The process includes the following steps implemented by the processing circuit: Control the transmitter to emit a pulse beam toward the target; Controlling the pixel unit to collect a plurality of light spots formed on the surface of the pixel unit after the pulse light beam reflected by the target is diffracted by the grating; A plurality of first flight times of the pulse light beam are calculated based on a plurality of photon signals output by the pixel unit, and a second flight time of the pulse light beam is obtained by performing curve fitting on the plurality of first flight times.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processing circuit, the steps of the distance measurement method according to claim 7 are implemented.

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