A flight time measurement system and method

Abstract

The present application relates to the field of optical measurement technology, and in particular to a flight time measurement system and method, the system comprising: an emitter configured to turn on at least one light source to emit a light signal toward a target object; a collector configured to actuate pixels corresponding to the turned-on light source under the control of a control and processing circuit to receive at least part of the light signal reflected back by the target object, the actuated pixels receive the light signal and output a photon detection signal to a readout circuit, the readout circuit is configured to generate a histogram according to the photon detection signal, and output a first flight time value of the corresponding pixel according to the histogram; the control and processing circuit is configured to obtain a second flight time value for multiple actuated pixels corresponding to a single turned-on light source in combination with multiple first flight time values ​​of the multiple actuated pixels. The embodiments of the present application can improve the accuracy of the measurement system.

Description

Technical Field

[0001] The present application relates to the field of optical measurement technology, and in particular to a time-of-flight measurement system and method. Background Art

[0002] Traditional ranging technologies are divided into two-way ranging technologies and one-way ranging technologies. Time of Flight (ToF) technology belongs to two-way ranging technology. This technology uses the flight time of the light signal between the transmitter and the collector to measure the distance of the target. At present, the measurement system based on ToF technology has been widely used in consumer electronics, unmanned vehicles, augmented reality (AR) and virtual reality (VR).

[0003] ToF technology can be divided into direct time of flight (Direct ToF, DToF) technology and indirect time of flight (Indirect ToF, IToF) technology. Among them, DToF technology measures the flight time of photons in the light beam from emission to reception based on time-correlated single photon counting (Time-Correlated Single Photon Counting, TCSPC) technology; IToF technology measures the phase delay of the reflected light beam relative to the emitted light beam, and then calculates the flight time based on the phase delay. Among them, DToF technology has the advantages of high signal-to-noise ratio, good sensitivity, and high accuracy, and has received more and more attention.

[0004] In the measurement system based on ToF technology, there is a one-to-one correspondence between the emission field of view of the emitter and the collection field of view of the collector. After each spot light beam emitted by the emitter to the target field of view, it will be reflected and imaged onto the corresponding pixel in the collector. In addition, in order to receive as many light signals of the reflected light spot as possible, it is usually necessary to combine multiple pixels together to form a pixel group to jointly collect the light signal in a reflected light spot. At this time, each emitted spot light beam will simultaneously activate the corresponding pixel group to collect the reflected light spot.

[0005] In practical applications, each pixel in a pixel group is usually set to share a readout circuit, and the photon detection signal generated by each pixel is sequentially input into the same readout circuit for drawing a histogram. Therefore, the drawing of the histogram only considers the time dimension, but does not consider the deviation caused by the different positions of each pixel, resulting in reduced measurement accuracy.

[0006] The disclosure of the above background technology content is only used to assist in understanding the concept and technical solution of the present application. It does not necessarily belong to the prior art of the present application. In the absence of clear evidence that the above content has been disclosed before the filing date of the present application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0007] The purpose of the embodiments of the present application is to provide a flight time measurement system and method, aiming to solve one or more technical problems in the related art.

[0008] To achieve the above-mentioned purpose, in the first aspect, an embodiment of the present application provides a flight time measurement system, comprising: an emitter, a collector, and a control and processing circuit. The emitter is configured to turn on at least one light source to emit a light signal toward a target object; the collector is configured to actuate the pixels corresponding to the light source under the control of the control and processing circuit to receive at least part of the light signal reflected back by the target object, the actuated pixels receive the light signal and output a photon detection signal to a readout circuit, the readout circuit is configured to generate a histogram according to the photon detection signal, and output a first flight time value of the corresponding pixel according to the histogram; the control and processing circuit is configured to obtain a second flight time value for a plurality of actuated pixels corresponding to a single light source in combination with a plurality of first flight time values ​​of the plurality of actuated pixels.

[0009] In some embodiments, the step of obtaining a second flight time value by combining multiple first flight time values ​​of the multiple actuated pixels includes: obtaining a first weight of each of the multiple actuated pixels, and performing weighted summation of the multiple first flight time values ​​of the multiple actuated pixels according to the first weight to obtain a second flight time value.

[0010] In some embodiments, the first weight is determined according to the grayscale value of the pixel.

[0011] In some embodiments, the step of combining the plurality of first flight time values ​​of the plurality of actuated pixels to obtain a second flight time value comprises:

[0012] The multiple first flight time values ​​of the multiple actuated pixels are used to perform waveform fitting of the emission light signal, and the peak value of the waveform obtained by fitting is obtained as the second flight time value.

[0013] In some embodiments, the emitted light signal waveform comprises a Gaussian waveform.

[0014] In some embodiments, the readout circuit includes a TDC circuit, a histogram circuit and a readout unit, each of the pixels is correspondingly connected to a TDC circuit, a histogram circuit and a readout unit, the TDC circuit is configured to generate a time signal of the corresponding pixel according to the photon detection signal, the histogram circuit is configured to accumulate the time signal to generate a histogram of the corresponding pixel, and the readout unit outputs a first flight time value of the corresponding pixel according to the histogram.

[0015] In a second aspect, an embodiment of the present application provides a method for measuring time of flight, comprising: controlling at least one light source in a transmitter to emit a light signal toward a target object; synchronously actuating pixels in a collector corresponding to the turned-on light source to receive at least part of the light signal reflected back by the target object; the actuated pixels receive the light signal and output a photon detection signal to a readout circuit, the readout circuit being configured to generate a histogram based on the photon detection signal, and output a first time of flight value of the corresponding pixel based on the histogram; for multiple actuated pixels corresponding to a single turned-on light source, a second time of flight value is obtained by combining multiple first time of flight values ​​of the multiple actuated pixels.

[0016] In some embodiments, the step of obtaining a second flight time value by combining multiple first flight time values ​​of the multiple actuated pixels includes: obtaining a first weight of each of the multiple actuated pixels, and performing weighted summation of the multiple first flight time values ​​of the multiple actuated pixels according to the first weight to obtain a second flight time value.

[0017] In some embodiments, the first weight is determined according to the grayscale value of the pixel.

[0018] In some embodiments, obtaining the second flight time value by combining the multiple first flight time values ​​of the multiple actuated pixels includes: fitting the waveform of the emitted light signal using the multiple first flight time values ​​of the multiple actuated pixels, and obtaining the peak value of the fitted waveform as the second flight time value.

[0019] In a third aspect, an embodiment of the present application provides an electronic device, comprising the time-of-flight measurement system described in any embodiment of the first aspect above; the transmitter and collector of the time-of-flight measurement system are arranged on the same side of the electronic device body.

[0020] The beneficial effect of the embodiments of the present application is that a more accurate flight time value is calculated by combining the multiple flight time values ​​included in the multiple actuated pixels corresponding to a single turned-on light source, and the flight time value of each pixel included in the multiple pixels receiving the same light spot beam is comprehensively considered, thereby improving the accuracy of the measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 paying creative labor.

[0022] Figure 1 A schematic diagram of the structure of a time-of-flight measurement system provided in one embodiment of the present application.

[0023] Figure 2 A schematic diagram of the structure of a pixel array provided in one embodiment of the present application.

[0024] Figure 3 A schematic diagram of the structure of a collector provided in one embodiment of the present application.

[0025] Figure 4 A schematic diagram of the structure of a collector provided in another embodiment of the present application.

[0026] Figure 5 A schematic diagram of an implementation flow of a flight time measurement method provided in one embodiment of the present application.

[0027] Figure 6 A schematic diagram of the structure of an electronic device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] It should be noted that when an element is referred to as being "connected" to another element, it may be directly connected to the other element or indirectly connected to the other element. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0030] See also Figure 1 The embodiment of the present application provides a flight time measurement system 10. The flight time measurement system 10 includes a transmitter 11, a collector 12, and a control and processing circuit 13.

[0031] In some embodiments, the transmitter 11 is used to transmit a transmission light beam 30 to the target area 20, and the transmission light beam 30 is emitted into the space of the target area 20 to illuminate the target in the space. At least part of the transmission light beam 30 is reflected by the target to form a reflection light beam 40, and at least part of the reflection light beam 40 is received by the collector 12; the control and processing circuit 13 is connected to the transmitter 11 and the collector 12 respectively, and the trigger signals of the transmitter 11 and the collector 12 are synchronized to calculate the time required for the light beam to be received or collected from the emission to the reflection back, that is, the flight time t between the transmission light beam 30 and the reflection light beam 40. Further, the distance D of the corresponding point on the target can be calculated by the following formula:

[0032] D=c·t / 2

[0033] Where c is the speed of light.

[0034] In some embodiments, the transmitter 11 includes a light source 111, an emitting optical element 112, a driver 113, etc. Among them, the light source 111 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 light source 111 can include one or more light sources. When multiple light sources are included, the light source 111 can be a one-dimensional or two-dimensional light source array composed of multiple light sources. Preferably, the light source array is a VCSEL array light source chip formed by generating multiple VCSEL light sources on a single semiconductor substrate, and the arrangement of the light sources in the light source array can be regular or irregular. The light beam emitted by the light source 111 can be visible light, infrared light, ultraviolet light, etc. The light source 111 emits a light beam outward under the control of the driver 113.

[0035] In one embodiment, the light source 111 is configured as a light source array composed of a plurality of light sources, wherein the light source array includes a plurality of groups of light sources, and each time a group of light sources is turned on to emit a spot light beam toward the target area, until the last group of light sources is turned on, thereby realizing scanning of the target area. A group of light sources may be one light source; or a group of light sources may be a plurality of light sources arranged into a linear light source, wherein the linear light source is formed by arranging a plurality of light sources in sequence; or a group of light sources may be a plurality of light sources arranged into other shapes such as a rectangle or an L-shape, etc., and the present application is not limited thereto. It should be noted that, more generally, the transmitter is configured to start a group of light sources at a time to emit a light signal, and a group of light sources is a working light source for a given area for each target object scanning, and the working light source may be one or more light sources.

[0036] In one embodiment, the light source 111 emits a pulsed light beam at a certain frequency (or pulse period) under the control of the driver 113 for direct time-of-flight measurement, and the frequency is set according to the measurement distance. It is understood that a part of the control and processing circuit 13 or a subcircuit that exists independently of the control and processing circuit 13 can also be used to control the light source 111 to emit a light beam.

[0037] The emission optical element 112 receives the light beam emitted from the light source 111 and shapes it to project it to the target area 20. In one embodiment, the emission optical element 112 receives the pulse light beam from the light source 111, and optically modulates the pulse light beam, such as diffraction, refraction, reflection, etc., and then emits the modulated light beam into space, such as a focused light beam, a flood light beam, a structured light beam, etc. The emission optical element 112 can be a combination of one or more of the forms of a lens, a liquid crystal element, a diffractive optical element, a microlens array, a metasurface optical element, a mask plate, a reflector, a MEMS galvanometer, etc.

[0038] In some embodiments, the collector 12 includes a pixel array 121, a filtering unit 122, and a readout circuit array ( Figure 1 ). Wherein, the filtering unit 122 is used to filter out background light or stray light. The pixel array 121 is composed of a plurality of pixels, and the pixel array 121 is configured to actuate a group of pixels under the control of the control and processing circuit 13 to collect at least part of the light signal reflected back by the target object and generate a corresponding photon detection signal. The readout circuit is used to receive the photon detection signal for processing to generate a histogram, and then output the flight time value according to the histogram. In one embodiment, the pixel array 121 is a pixel array composed of a plurality of pixels, and the pixel can be a single photon avalanche diode (SPAD), and a pixel can include one or more SPADs. The pixel array 121 is actually a SPAD array composed of a plurality of SPADs, and the SPAD array is an addressable matrix. Generally, the control and processing circuit 13 can select the pixel group to be actuated, and the pixel array 121 is configured to actuate a plurality of pixel groups at a time to receive light signals under the control of the control and processing circuit 13, and each reflected light beam 40 is imaged into a pixel group. SPAD, also known as Geiger-mode avalanche photodiode (GM-APD), is a detector that can capture individual photons with an arrival time resolution of tens of picoseconds, and can be manufactured in a dedicated semiconductor process or in standard complementary metal oxide semiconductor (CMOS) technology. As a non-limiting example, taking the case of turning on a light source to emit a light signal and synchronously actuating a pixel group corresponding to the light source to receive a reflected light signal, as shown in FIG. Figure 2 As shown, a light source emits a spot light beam, and the spot 21 is imaged onto a pixel group 22, and the pixel group 22 includes 2*2 pixels 23, that is, 4 pixels 23. In one embodiment, for an off-axis time-of-flight measurement system, considering the deviation caused by parallax, the size of the pixel group can also be set larger than the spot size, so that the pixel group includes the offset caused by the parallax of the spot.

[0039] The pixel array 121 is connected to a readout circuit array. Specifically, each pixel in the pixel array 121 is connected to a readout circuit. The readout circuit receives and accumulates the photon detection signal from the corresponding connected pixel to generate a histogram of the pixel and outputs the flight time value of the pixel according to the histogram. In some embodiments, the readout circuit includes one or more devices such as a signal amplifier, a time-to-digital converter (TDC), an analog-to-digital converter (ADC), and a readout (R / O) unit.

[0040] In one embodiment, the readout circuit includes a TDC circuit, a histogram circuit, and an R / O unit, such as Figure 3 As shown, each pixel in the collector is connected to a TDC circuit, a histogram circuit and an R / O unit. The pixel receives the pulse light signal reflected by the target and generates a photon detection signal. The TDC circuit receives and calculates the time interval of these photon detection signals and converts the time interval into a time code. The histogram circuit accumulates and counts the time code output by the TDC circuit to generate a histogram of the pixel. The R / O unit outputs the flight time value of the pixel according to the histogram generated by the histogram circuit. Further, the R / O unit can be electrically connected to the control and processing circuit, and the control and processing circuit can receive the flight time value of the pixel output by the R / O unit, and calculate a more accurate flight time value in combination with the multiple flight time values ​​of the multiple pixels included in the actuated pixel group. In some other embodiments, the distance information of the target object can be further calculated based on the more accurate flight time value.

[0041] It should be noted that, when a pixel includes multiple SPADs, in one embodiment, the photon detection signals generated by the multiple SPADs included in the same pixel can be accumulated and counted to obtain the flight time value of the pixel. For example, the multiple SPADs included in the same pixel can be connected to the same readout circuit. In another embodiment, the multiple SPADs included in the same pixel can each generate a flight time value, and then the flight time value of the pixel is calculated in combination with the flight time values ​​of the multiple SPADs. For example, the multiple SPADs included in the same pixel are respectively connected to a readout circuit. It should be understood that the flight time of a pixel is calculated in combination with the flight time of multiple SPADs of a pixel. The relevant description of calculating the flight time value of the pixel group in combination with the flight time of multiple pixels of the pixel group can be referred to, and will not be repeated here.

[0042] In some embodiments, see Figure 1 As shown, the collector 12 also includes a receiving optical element 123. The receiving optical element 123, the filtering unit 122 and the pixel unit 121 are sequentially arranged along the propagation path of the optical signal. The receiving optical element 123 is used to receive at least part of the light beam reflected back by the target object and guide the at least part of the light beam to the pixel array 121 to image the target object to the pixel array.

[0043] The control and processing circuit 13 synchronizes the trigger signals of the emitter 11 and the collector 12. Optionally, the control and processing circuit 13 can control the light source that needs to be turned on and / or off at each given time, and the pixels that need to be actuated (or activated) and / or deactivated. The histogram generated by the histogram circuit, the characteristics of the TDC circuit, etc. (such as the photon arrival time, etc.) can all be transmitted to the control and processing circuit 13 for subsequent use. The control and processing circuit 13 obtains the flight time values ​​of each of the multiple pixels included in each actuated pixel group, and calculates the flight time value of the pixel group in combination with the flight time values ​​of the multiple pixels included. Further, the distance information of the target object can be calculated based on the flight time value of the pixel group. In one embodiment, the actuated pixel responds to the incident single photon and outputs a photon detection signal, the readout circuit receives the photon detection signal from the corresponding connected pixel for processing to generate a histogram and output the flight time value of the pixel, and the control and processing circuit 13 obtains the flight time value of the pixel group in combination with the multiple flight time values ​​of the multiple pixels included in the actuated pixel group. Specifically, the readout circuit calculates the number of photons collected by the corresponding connected pixels to form continuous time bins. These time bins are connected together to form a statistical histogram for reproducing the time series of the reflected light pulses, and the flight time of the light beam from emission to reception is identified by peak matching and filtering detection. It can be understood that the control and processing circuit 13 can be an independent dedicated circuit, such as a dedicated system-on-chip (System on Chip, SOC), a readily available field-programmable gate array (Field-Programmable Gate Array, FPGA) chip, an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC) chip, etc., and can also include a general processing circuit. The control and processing circuit 13 combines multiple flight time values ​​of multiple pixels to obtain the flight time value of the pixel group. Although some resource overhead is increased, the comprehensive consideration of the flight time values ​​of multiple pixels improves the accuracy of the measurement results of the measurement system.

[0044] In some embodiments, the flight time measurement system 10 further includes a memory. The memory can be used to store a pulse coding program, and the coding program is used to control the excitation time and emission frequency of the light beam emitted by the light source 111. The memory can be used to store time information, histograms, flight time values, distance information, etc.

[0045] In one embodiment, the control and processing circuit 13 is configured to obtain the first weight of each of the multiple pixels included in the actuated pixel group corresponding to any turned-on light source, and perform weighted summation of the multiple flight time values ​​of the multiple pixels according to the first weight to obtain the flight time value of the pixel group.

[0046] In one embodiment, the first weight is determined according to the grayscale value of the pixel. As a possible implementation, the number of photon detection signals generated by the pixel is used as the grayscale value of the pixel. In this implementation, Figure 4 As shown, each pixel is connected to a readout circuit, and the readout circuit includes a TDC circuit, a histogram circuit and an R / O unit, and also includes a counting circuit. The counting circuit receives and counts the number of photon detection signals of the corresponding connected pixels, and transmits the number to the control and processing circuit 13. As another possible implementation, the number of photons in each time bin in the histogram corresponding to the pixel is summed as the grayscale value of the pixel. In this implementation, each pixel is connected to a readout circuit, and the readout circuit transmits the histogram of the corresponding connected pixel to the control and processing circuit 13, and the control and processing circuit 13 sums the number of photons in each time bin in the histogram corresponding to the pixel as the grayscale value of the pixel.

[0047] As one implementation method, for an actuated pixel group corresponding to any light source, grayscale values ​​of multiple pixels included in the pixel group are obtained, the grayscale values ​​of the multiple pixels are normalized respectively to obtain first weights of the multiple pixels, and the flight time value of the pixel group is obtained by weighted summing the flight time values ​​of the multiple pixels according to the first weight.

[0048] As a non-limiting example, the actuated pixel group includes 4 pixels. Figure 2 As shown, a light spot 21 is imaged on a pixel group 22, and the pixel group 22 includes four pixels 23, the four pixels are respectively an upper left pixel, a lower left pixel, an upper right pixel and a lower right pixel, and the flight time value of the four pixels is recorded as ToF1 i , the gray value of the 4 pixels is recorded as G i , i is an integer from 1 to 4, and the first weight of the four pixels is K i =G i / (ΣG i ),ΣG i =G1+G2+G3+G4, the flight time value ToF2 of the pixel group 22 =K1*ToF11+K2*ToF12+K3*ToF13+K4*ToF14.

[0049] It should be noted that other normalization methods may be used in other examples, and this application does not impose any specific restrictions on this.

[0050] As another implementation, for an actuated pixel group corresponding to any light source, grayscale values ​​of multiple pixels included in the pixel group are obtained, the grayscale values ​​of the multiple pixels are multiplied by a preset constant coefficient respectively to obtain a first weight of the multiple pixels, and the flight time values ​​of the multiple pixels are weighted and summed according to the first weight to obtain the flight time value of the pixel group. In this implementation, the grayscale value is multiplied by a constant coefficient to adjust the weight generated by the grayscale value.

[0051] As a non-limiting example, the actuated pixel group includes 4 pixels. Figure 2 As shown, a light spot 21 is imaged on a pixel group 22, and the pixel group 22 includes four pixels 23, the four pixels are respectively an upper left pixel, a lower left pixel, an upper right pixel and a lower right pixel, and the flight time value of the four pixels is recorded as ToF1 i , the gray value of the 4 pixels is recorded as G i , i is an integer from 1 to 4, and the first weight of the four pixels is K i =r i *G i , the flight time value ToF2 of the pixel group 22 = r1*G1*ToF11+r2*G2*ToF12+r3*G3*ToF13+r4*G4*ToF14, wherein r1, r2, r3 and r4 are four constant coefficients, and the constant coefficients can be empirical values.

[0052] In another embodiment, the control and processing circuit 13 is configured to perform waveform fitting of the emission light signal using multiple flight time values ​​of multiple pixels included in the pixel group for the actuated pixel group corresponding to any light source, and obtain the peak value of the fitted Gaussian waveform as the flight time value of the pixel group. In this embodiment, the flight time of the pixel is fitted according to the emission light signal waveform, and the flight time value of the pixel group with higher accuracy can be obtained, thereby improving the accuracy of the measurement result of the measurement system.

[0053] In one embodiment, the emitted light signal waveform includes a Gaussian waveform, such as a three-dimensional Gaussian waveform, etc. The present application does not specifically limit the emitted light signal waveform.

[0054] In some embodiments, the time-of-flight measurement system 10 may also include devices such as a color camera, an infrared camera, and an IMU. The combination of these devices may realize richer functions, such as 3D texture modeling, infrared face recognition, SLAM, and other functions.

[0055] In some embodiments, continue to refer to Figure 1As shown, the transmitter 11 includes a light source 111 and a driver 113 for driving the light source 111. The light source 111, driven by the driver 113 and under the control of the control and processing circuit 13, causes a given area (ie, the aforementioned group of light sources) to emit a light signal.

[0056] Further, in some embodiments, continue to refer to Figure 1 As shown, the transmitter 11 also includes an emission optical element 112, which is used to project the light signal to the target object and form an illumination spot on the target object. Optionally, the emission optical element 112 includes but is not limited to a collimator, a diffraction optical element, etc., or a combination of several thereof.

[0057] In some implementations, the light source 111 is a VCSEL array light source chip formed by generating multiple VCSEL light sources on a single semiconductor substrate. The light source 111 can emit a pulse light beam 30 to a target object at a certain frequency (or pulse period) under the control of the control and processing circuit 13, and the pulse light beam 30 is projected onto the target object through the emission optical element 112 to form an illumination spot.

[0058] Figure 5 FIG. 1 is a time-of-flight measurement method provided by an embodiment of the present application. The time-of-flight measurement method can be applied to the aforementioned Figures 1 to 3 The flight time measurement system of the embodiment. In some embodiments, the flight time measurement method can be performed by a control and processing circuit of the flight time measurement system. In some embodiments, the flight time measurement method can be performed by an electronic device.

[0059] like Figure 5 As shown, the flight time measurement method may include the following steps S41 to S43.

[0060] S41, controlling at least one light source in the transmitter to transmit a light signal toward a target object.

[0061] The emitter may be a single point light source including one light source, or a light source array including multiple light sources.

[0062] S42, synchronously actuating pixels in the collector corresponding to the turned-on light sources to receive at least a portion of the light signal reflected back by the target object.

[0063] The actuated pixel receives the light signal and outputs the photon detection signal to the readout circuit, and the readout circuit is configured to generate a histogram according to the photon detection signal and output the first flight time value of the corresponding pixel according to the histogram. The pixels are connected to the readout circuit in a one-to-one correspondence.

[0064] In one embodiment, each turned-on light source corresponds to a pixel group, and a pixel group includes a plurality of pixels.

[0065] S43, for a plurality of actuated pixels corresponding to a single turned-on light source, obtain a second flight time value by combining a plurality of first flight time values ​​of the plurality of actuated pixels.

[0066] In some embodiments, step S43 includes: for multiple actuated pixels corresponding to a single turned-on light source, obtaining first weights of the multiple actuated pixels respectively, and performing weighted summation of multiple first flight time values ​​of the multiple actuated pixels according to the first weights to obtain a second flight time value.

[0067] In some other embodiments, step S43 includes: for multiple actuated pixels corresponding to a single turned-on light source, using multiple first flight time values ​​of the multiple actuated pixels to perform waveform fitting of the emitted light signal, and obtaining the peak value of the fitted Gaussian waveform as the second flight time value.

[0068] It should be noted that the flight time measurement method embodiment is similar to the above-mentioned embodiment and will not be described in detail here.

[0069] An embodiment of the present application also provides an electronic device. Figure 6 As shown, the electronic device 600 includes: a processor 60, a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60, such as a program for flight time measurement. When the processor 60 executes the computer program 62, the steps of the flight time measurement method in any of the above embodiments are implemented, such as Figure 5 Steps S41 to S43 are shown.

[0070] Exemplarily, the computer program 62 may be divided into one or more modules / units, which are stored in the memory 61 and executed by the processor 60 to complete the present application. The one or more modules / units may be a series of computer program instruction segments capable of completing specific functions, which are used to describe the execution process of the computer program 62 in the electronic device 600.

[0071] Those skilled in the art will understand that Figure 6 It is only an example of the electronic device 600 and does not constitute a limitation of the electronic device 600. The electronic device 600 may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the electronic device 600 may also include input and output devices, network access devices, buses, etc.

[0072] The processor 60 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), ASICs, FPGAs or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0073] The memory 61 may be an internal storage unit of the electronic device 600, such as a hard disk or memory of the electronic device 600. The memory 61 may also be an external storage device of the electronic device 600, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 600. Further, the memory 61 may also include both an internal storage unit of the electronic device 600 and an external storage device. The memory 61 is used to store the computer program and other programs and data required by the electronic device. The memory 61 may also be used to temporarily store data that has been output or is to be output.

[0074] An embodiment of the present application further provides an electronic device, which includes the flight time measurement system of any of the above embodiments, wherein a transmitter and a collector of the flight time measurement system are arranged on the same side of the electronic device body.

[0075] As a non-limiting example, the electronic device may be a lidar or the like.

[0076] An embodiment 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 processor, the steps in each of the above-mentioned flight time measurement method embodiments can be implemented.

[0077] An embodiment of the present application provides a computer program product. When the computer program product is run on an electronic device, the electronic device can implement the steps in each of the above-mentioned flight time measurement method embodiments.

[0078] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0079] Those of ordinary skill 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 to be beyond the scope of this application.

[0080] In the embodiments provided in the present application, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are merely schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0081] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0082] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0083] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, ROM, RAM, electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electric carrier signals and telecommunication signals.

[0084] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A time-of-flight measurement system, characterized in that: include: Transmitter, collector, and control and processing circuits, The transmitter is configured to turn on at least one light source to transmit a light signal toward a target object; The collector is configured to actuate pixels of one or more pixel groups corresponding to the light source under the control of the control and processing circuit to receive at least part of the light signal reflected by the target object, each reflected light beam is imaged to a pixel group, the actuated pixels receive the light signal and output a photon detection signal to a readout circuit, each of the actuated pixels is connected to a corresponding readout circuit, and the readout circuit is configured to generate a histogram according to the photon detection signal, and output a first flight time value of the corresponding pixel according to the histogram; The control and processing circuit is configured to obtain, for a plurality of actuated pixels corresponding to a single light source, a second flight time value according to a plurality of first flight time values ​​of the plurality of actuated pixels, including: Obtaining first weights of the plurality of actuated pixels respectively, and performing weighted summation on a plurality of first time-of-flight values ​​of the plurality of actuated pixels according to the first weights to obtain a second time-of-flight value; The first weight is determined according to the grayscale value of the pixel, and the grayscale value of the pixel is the sum of the number of photons in each time bin in the histogram corresponding to the pixel.

2. The time-of-flight measurement system according to claim 1, wherein: The readout circuit includes a TDC circuit, a histogram circuit and a readout unit, each of the pixels is correspondingly connected to a TDC circuit, a histogram circuit and a readout unit, the TDC circuit is configured to generate a time signal of the corresponding pixel according to the photon detection signal, the histogram circuit is configured to accumulate the time signal to generate a histogram of the corresponding pixel, and the readout unit outputs a first flight time value of the corresponding pixel according to the histogram.

3. A method for measuring time of flight, characterized in that: include: Controlling at least one light source in the transmitter to emit a light signal toward the target object; Synchronously actuating pixels of one or more pixel groups corresponding to the light source in a collector to receive at least a portion of the light signal reflected back by the target object, and imaging each reflected light beam into one pixel group; The actuated pixel receives the light signal and outputs a photon detection signal to a readout circuit, each of the actuated pixels is connected to a corresponding readout circuit, and the readout circuit is configured to generate a histogram according to the photon detection signal and output a first flight time value of the corresponding pixel according to the histogram; For a plurality of actuated pixels corresponding to a single light source, obtaining a second flight time value by combining a plurality of first flight time values ​​of the plurality of actuated pixels comprises: Obtaining first weights of the plurality of actuated pixels respectively, and performing weighted summation on a plurality of first time-of-flight values ​​of the plurality of actuated pixels according to the first weights to obtain a second time-of-flight value; The first weight is determined according to the grayscale value of the pixel, and the grayscale value of the pixel is the sum of the number of photons in each time bin in the histogram corresponding to the pixel.

Images