WO2022021797A1

WO2022021797A1 - Distance measurement system and distance measurement method

Info

Publication number: WO2022021797A1
Application number: PCT/CN2020/141722
Authority: WO
Inventors: 苏健; 朱亮; 闫敏
Original assignee: 深圳奥锐达科技有限公司
Priority date: 2020-07-25
Filing date: 2020-12-30
Publication date: 2022-02-03
Also published as: CN111856433A; CN111856433B

Abstract

A distance measurement system, a distance measurement method and a computer device. The system (10) comprises a transmitter (11) and a collector (12), which are arranged along a baseline, and a processing circuit (13, 32), wherein the transmitter (11) comprises a light source array (21) composed of a plurality of light sources (213, 214), the light source array (21) comprises a plurality of sub-light source arrays (211, 212), and the sub-light source arrays (211, 212) are configured to be opened one by one along a baseline direction so as to emit spot light beams (30); the collector (12) comprises a pixel array (31) composed of a plurality of pixels (312), the pixel array (31) comprises a plurality of sub-pixel arrays (311), and the plurality of sub-pixel arrays (311) are configured to collect photons, in light beams (40), which are reflected by the spot light beams (30) by means of a target object (20) to be measured, and to form a photonic signal; and the processing circuit (13, 32) comprises a plurality of sub-processing circuits (323), and the sub-processing circuits (323) are connected to the sub-pixel arrays (311) in one-to-one correspondence, so as to control the pixels (312) in the sub-pixel arrays (311) to start, collect the photons in the reflected light beams (40) and calculate a time of flight. By means of the system (10), the spatial resolution is improved, the problem of superpixel overlap is solved, the distance measurement accuracy is improved, and the process cost and complexity are also effectively reduced.

Description

A distance measurement system and measurement method

This application claims the priority of the Chinese patent application filed on July 25, 2020 with the application number 202010726629.X and the title of the invention is "a distance measurement system and measurement method", the entire contents of which are incorporated by reference in in this application.

technical field

The present application relates to the technical field of optical ranging, and in particular, to a distance measurement system and a measurement method.

Background technique

The time of flight principle (TOF, Time of Flight) can be used to measure the distance of the target to obtain a depth image containing the depth value of the target, and the distance measurement system based on the time of flight principle has been widely used in consumer electronics, unmanned aerial vehicles, AR/VR and other fields. The distance measurement system based on the time-of-flight principle usually includes an emitter and a collector. The emitter is used to emit a pulsed beam to illuminate the target field of view, and the collector is used to collect the reflected beam, and the time required for the beam to be reflected and received is calculated to calculate the object. distance.

Currently, collectors in distance measurement systems based on the time-of-flight principle include pixel arrays, in particular, pixel arrays based on single-photon avalanche photodiodes (SPADs). SPADs, also known as Geiger Mode Avalanche Photodiodes (GM-APDs), are detectors capable of capturing individual photons with time-of-arrival resolution on the order of tens of picoseconds and can be fabricated in dedicated semiconductor processes or in standard CMOS technology come out. For ranging, the SPAD array is connected to a time-to-digital converter (TDC) and outputs photonic signals to the TDC. As described in Chinese patent CN201910888927.6, in order to receive as many optical signals of reflected light beams as possible, multiple pixels are usually used in combination, and the corresponding pixel area is called "combined pixel". In order to ensure the spatial resolution of each ranging point, it is usually necessary to input the photon signal output by the combined pixel into the same TDC.

In the prior art, due to the limited size of the combined pixels and the influence of system tolerance and parallax, the light spot imaged by the reflected beam onto the pixel array is prone to be out of bounds and the ranging information is lost. Therefore, strict control of tolerance and compression is required. baseline, which increases the design difficulty. On the other hand, the number of TDCs is large and needs to be connected to each pixel or combined pixel. Since the pixel array is a two-dimensional planar structure, only three-dimensional stacked process lines can be used, which increases the design cost and complexity. The above problems make it difficult to improve the spatial resolution of the ranging system.

SUMMARY OF THE INVENTION

The purpose of the present application is to provide a distance measurement system and a measurement method to solve at least one of the above background technical problems.

An embodiment of the present application provides a distance measurement system, including an emitter and a collector arranged along a baseline, and a processing circuit connected to the emitter and the collector; wherein the emitter includes a light source array composed of multiple light sources, The light source array includes a plurality of sub-light source arrays, and the sub-light source arrays are configured to be turned on one by one along the baseline direction for emitting spot light beams; the collector includes a pixel array composed of a plurality of pixels, and the pixel array includes a plurality of sub-light sources. a pixel array, the plurality of sub-pixel arrays are configured to collect photons in the reflected beam of the spot beam reflected by the target object to be measured and form a photon signal; the processing circuit includes a plurality of sub-processing circuits, the sub-processing circuits One-to-one connection with the sub-pixel array to control the pixels in the sub-pixel array to start collecting photons in the reflected beam, and calculate the spot beam according to the photon signal output by the sub-pixel array The time-of-flight from emission to reflection back being acquired.

In some embodiments, the sub-light source array includes a row or a column of light sources; the sub-light source array is activated in sub-periods one by one under the control of the driving circuit to project the spot beam to the target field of view; wherein, in a measurement stage only A sub-light source array is activated until all sub-light source arrays are activated to complete the scanning of the entire target field of view.

In some embodiments, the scanning direction of the light source array is the same as the baseline direction.

In some embodiments, the pixel array is disposed in the same plane as the processing circuit.

In some embodiments, a diffractive optical element is also included, and the spot light beam emitted by the sub-light source array is replicated by the diffractive optical element and projected into the target field of view to form two sets of spot projection patterns, so as to scan the target field of view synchronously of the two regions.

In some embodiments, the pixel array is divided into a first pixel array and a second pixel array, each pixel array includes a plurality of the sub-pixel arrays; the processing circuit is correspondingly divided into a first processing circuit and a second processing circuit Each processing circuit includes a plurality of the sub-processing circuits; the first processing circuit and the second processing circuit are respectively arranged on both sides of the pixel array and are respectively connected with the first pixel array and the second pixel array. The pixel arrays are connected in a one-to-one correspondence, and are used for receiving the photon signals output by the pixels in the corresponding sub-pixel array and calculating the flight time of the light beam.

The embodiment of the present application also provides a distance measurement method, comprising the following steps:

S10. Control the sub-light source arrays in the transmitter to be turned on one by one, and emit spot light beams toward the target field of view; wherein, the transmitter includes a light source array composed of a plurality of light sources, and the light source array includes a plurality of the sub-light source arrays;

S20. Control the activation of the pixels in the sub-pixel array of the collector to collect photons in the reflected speckle beam, and form a photon signal; wherein the collector includes a pixel array composed of a plurality of pixels, and the pixels an array including a plurality of the sub-pixel arrays;

S30. Use the sub-processing circuit in the processing circuit to receive the photon signal output by the corresponding sub-pixel array, and calculate the time-of-flight of the speckle beam from being emitted to being collected according to the photon signal.

In some embodiments, the processing circuit is configured to include a plurality of the sub-processing circuits; wherein the sub-pixel array is connected to the sub-processing circuits in a one-to-one correspondence.

In some embodiments, in step S10, the sub-light source arrays are turned on one by one along the baseline direction to emit spot beams, until all sub-light source arrays are activated, and the scanning of the target field of view is completed; Or the spot light beams emitted by the light sources in the same row are all incident on some pixels in the same sub-pixel array, and the flight time of the light beams is calculated by the same sub-processing circuit.

Embodiments of the present application further provide a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor; wherein, when the processor executes the computer program, at least A distance measurement method is realized, and the distance measurement method includes the following steps: S10, controlling the sub-light source arrays in the transmitter to be turned on one by one, and emitting a spot beam toward the target field of view; wherein, the transmitter includes a plurality of light sources. A light source array, the light source array includes a plurality of the sub-light source arrays; S20, controlling the pixels in the sub-pixel array of the collector to start to collect the photons in the reflected speckle beam, and form a photon signal; wherein, the The collector includes a pixel array composed of a plurality of pixels, and the pixel array includes a plurality of the sub-pixel arrays; S30. Use the sub-processing circuit in the processing circuit to receive the photon signal output by the corresponding sub-pixel array, and The time-of-flight of the speckle beam from being emitted to being collected is calculated from the photon signal.

An embodiment of the present application provides a distance measurement system, including an emitter and a collector arranged along a baseline, and a processing circuit; wherein the emitter includes a light source array composed of multiple light sources, the light source array includes multiple sub-light source arrays, and the sub-light sources The array is configured to be turned on one by one along the baseline direction to emit the spot beams; the collector includes a pixel array composed of a plurality of pixels, the pixel array includes a plurality of sub-pixel arrays, and the plurality of sub-pixel arrays are configured to collect the spot beams reflected by the target object to be tested. The photons in the beam of the beam are reflected and a photon signal is formed; the processing circuit includes a plurality of sub-processing circuits, and the sub-processing circuits are connected with the sub-pixel array in one-to-one correspondence to control the activation of the pixels in the sub-pixel array, collect photons in the reflected beam, and calculate the flight time. The measurement system of the embodiment of the present application improves the spatial resolution, solves the problem of superpixel overlap, and improves the distance measurement accuracy; at the same time, the readout circuit and the pixel array are designed on the same plane, which reduces the TDC circuit and the histogram circuit. , effectively reducing the cost and complexity of the process.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a schematic diagram of a distance measurement system according to an embodiment of the present application.

FIG. 2 is a schematic diagram of a light source array of a distance measurement system according to an embodiment of the present application.

FIG. 3 is a schematic diagram of a pixel unit of a distance measurement system according to an embodiment of the present application.

4 is a schematic diagram of a projected speckle pattern of a distance measurement system according to an embodiment of the present application.

FIG. 5 is a schematic diagram of a pixel unit of a distance measurement system according to another embodiment of the present application.

FIG. 6 is a flowchart of a distance measurement method according to still another embodiment of the present application.

detailed description

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

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, the connection can be used for either a fixing function or a circuit connecting function.

It is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top" , "bottom", "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that The device or element must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as a limitation of the present application.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second" may expressly or implicitly include one or more of that feature. In the description of the embodiments of the present application, "plurality" means two or more, unless otherwise expressly and specifically defined.

1 is a schematic diagram of a distance measurement system according to an embodiment of the present application. The distance measurement system 10 includes a transmitter 11 , a collector 12 , and a processing circuit 13 connected to the transmitter 11 and the collector 12 respectively. Wherein, the transmitter 11 is used to emit a light beam 30 to the target area 20, and the light beam is emitted into the space of the target area to illuminate the target object in the space; at least part of the emitted light beam 30 is reflected by the target area 20 to form a reflected beam 40, and the reflected beam 40 At least a part of the light beams are received by the collector 12; the processing circuit 13 is connected to the transmitter 11 and the collector 12 respectively, and synchronizes the trigger signals of the transmitter 11 and the collector 12 to calculate the time required for the beam to be received from emission to reflection , namely the flight time t between the emitted light beam 30 and the reflected light beam 40, and further, the distance D of the corresponding point on the target object can be calculated by the following formula:

D=c t/2 (1)

where c is the speed of light.

The transmitter 11 includes a light source 111, an emission optical element 112, a driver 113, and the like. The light source 111 may be a light emitting diode (LED), a laser diode (LD), an edge emitting laser (EEL), a vertical cavity surface emitting laser (VCSEL), etc., or a one-dimensional or two-dimensional light source composed of multiple light sources array. 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 may be regular or irregular. The light beam emitted by the light source 111 may be visible light, infrared light, ultraviolet light, or the like. The light source 111 emits light beams outward under the control of the driver 113 .

In some embodiments, the light source 111 emits a pulsed beam at a certain frequency (pulse period) under the control of the driver 113, which can be used in direct time-of-flight (Direct TOF) measurement, and the frequency is set according to the measurement distance. It can be understood that, a part of the processing circuit 13 or a sub-circuit existing independently of the processing circuit 13 can also be used to control the light source 111 to emit light beams.

The emission optical element 112 receives the light beam emitted from the light source 111 and shapes it to project it onto the target area. In some embodiments, the transmitting optical element 112 receives the pulsed light beam from the light source 111, performs optical modulation on the pulsed light beam, such as modulation of diffraction, refraction, reflection, etc., and then emits the modulated light beam into space, such as a focused beam, Flood beams, structured light beams, etc. The emission optical element 112 may be one or a combination of one or more of a lens, a liquid crystal element, a diffractive optical element, a microlens array, a metasurface optical element, a mask, a mirror, a MEMS galvanometer, and the like.

The collector 12 includes a pixel unit 121, a filter unit 122 and a receiving optical element 123; wherein, the receiving optical element 123 is used to receive at least part of the light beam reflected back by the target and guide it to the pixel unit 121, and the filter unit 122 is used to filter out the background light or stray light. The pixel unit 121 includes a two-dimensional pixel array composed of a plurality of pixels; in some embodiments, the pixel unit 121 is a pixel array composed of a single-photon avalanche photodiode (SPAD), and the SPAD can respond to an incident single photon and output A signal indicating the time of arrival of the received photon response at each SPAD enables the acquisition of weak optical signals and the calculation of time of flight using methods such as time-correlated single photon counting (TCSPC).

Generally, it also includes a readout circuit (not shown in the figure) composed of one or more of a signal amplifier, a time-to-digital converter (TDC), a digital-to-analog converter (ADC) and other devices connected to the pixel unit 121 . ). These circuits can be integrated with the pixel, as a part of the pixel unit, or as a part of the processing circuit 13 , and will be regarded as a part of the processing circuit 13 for ease of description later.

The processing circuit 13 synchronizes the trigger signals of the transmitter 11 and the collector 12, processes the photon signal of the pixel collected beam, and calculates the distance information of the target to be measured based on the flight time of the reflected beam. In some embodiments, the SPAD outputs a photon signal in response to an incident single photon, and the processing circuit 13 receives the photon signal and performs signal processing to obtain the time-of-flight of the light beam. Specifically, the processing circuit 13 calculates the number of collected photons to form continuous time bins, and these time bins are connected together to form a statistical histogram to reproduce the time series of reflected light beams, and use peak matching and filter detection to identify the reflected light beam from emission to reflection Returns the received flight time. It can be understood that the processing circuit 13 may be an independent dedicated circuit, such as a dedicated SOC chip, an FPGA chip, an ASIC chip, etc., or may include a general-purpose processing circuit.

In some embodiments, the distance measurement system 10 further includes a memory for storing a pulse encoding program, and the encoding program is used to control the excitation time, emission frequency, etc. of the light beam emitted by the light source 111 .

In some embodiments, the distance measurement system 10 may further include devices such as a color camera, an infrared camera, and an IMU, and the combination with these devices can realize more abundant functions, such as 3D texture modeling, infrared face recognition, SLAM and other functions.

In some embodiments, the transmitter 11 and the collector 12 may also be arranged in a coaxial form, that is, the two are realized by optical devices with reflection and transmission functions, such as a half mirror and the like.

Referring to FIG. 2 , FIG. 2 is a schematic diagram of a light source array in an embodiment of the present application. The light source array 21 is configured to be composed of a plurality of light sources 213 arranged on a single substrate (or on multiple substrates); wherein, the light source array 21 may be one-dimensional or two-dimensional, and may be regularly arranged It can also be arranged irregularly. Preferably, the light source array 21 is an array VCSEL chip composed of a plurality of VCSEL light sources arranged on a semiconductor substrate. The light source array 21 can emit light beams of any wavelength, such as visible light, infrared light, ultraviolet light, and the like. The light source array 21 emits light under the modulation driving of the driving circuit (which may be a part of the processing circuit 13 ), such as continuous wave modulation, pulse modulation, etc. The light source array 21 can also emit light in groups under the control of the driving circuit.

In some embodiments, the light source array 21 is configured to include a plurality of

sub-light source arrays

211, 212; each sub-light source array includes a row or a column of light sources, which needs to be set according to the direction of the baseline. The sub-light source arrays are activated one by one under the control of the driving circuit to project the spot beams to the target field of view, and only one sub-light source array is activated in a measurement stage until all sub-light source arrays are activated, and the entire target field of view is completed. Scanning; wherein, the scanning direction of the light source array (the activation sequence of the sub-light source array) is the same as the baseline direction (the connection line between the emitter and the collector). In an embodiment of the present application, assuming that the baseline direction is the vertical direction (y direction), the sub-light source array is configured to include a row of light sources, and the sub-light source array is sequentially activated in the y direction to complete a frame of scanning. As shown in FIG. 2 , the light source array 21 includes 4×5 light sources, and each sub-light source array includes 5 light sources. In some embodiments, each sub-light source array may also be disposed on a separate substrate, and controlled by different driving circuits to emit light in groups. Hereinafter, the present application will be described in detail by taking the base line direction as the y direction as an example, and the vertical base line direction is set as the x direction.

Referring to FIG. 3 , FIG. 3 is a schematic diagram of a pixel unit in an embodiment of the present application. The pixel unit includes a pixel array 31 and a processing circuit 32 , wherein the pixel array 31 includes a two-dimensional array composed of a plurality of pixels 312 , and the processing circuit 32 includes an array processing circuit composed of a plurality of TDC circuits 321 and a plurality of histogram circuits 322 . The pixel array 31 is used to collect at least part of the light beams reflected back by the target object and generate corresponding photon signals, and the processing circuit 32 is used to process the photon signals to draw a histogram reflecting the pulse waveform emitted by the light source in the transmitter; further , you can also calculate the flight time according to the histogram, and finally output the result.

In some embodiments, the pixel array 31 and the processing circuit 32 are disposed in the same plane, the pixel array 31 is configured to include a plurality of sub-pixel arrays 311 ; the processing circuit 32 is configured to include a plurality of sub-processing circuits 323 , each sub-pixel array 311 Connected to each sub-processing circuit 323 in a one-to-one correspondence, when any pixel in the sub-pixel array 311 receives a photon and generates a photon signal, the sub-processing circuit 323 can calculate the flight time corresponding to the photon signal. The number of sub-pixel arrays 311 is determined by the number of spot beams emitted by the transmitter in one measurement stage.

In some embodiments, when the transmitter 11 emits a spot beam to the object to be measured, the spot beam is reflected by the object to be measured, and the pixel unit in the collector 12 will guide the spot beam to the corresponding pixel, wherein the configuration of a single spot beam The imaging light spot is incident on the "combined pixel" composed of the corresponding multiple pixels. As shown in Figure 3, a single spot corresponds to a composite pixel consisting of 4 pixels. The size of the combined pixel can be specifically set according to the actual situation, and includes at least one pixel. When the transmitter 11 and the collector 12 are set off-axis, due to the existence of parallax, it is necessary to consider the situation that the light spot is displaced when the object to be measured is far and near. Generally, the light spot will shift along the baseline direction. This requires setting a pixel area (called a super pixel) composed of a plurality of pixels exceeding the number of combined pixels for receiving the reflected speckle beam. When setting the size of superpixels, the ranging range and baseline length of the system need to be considered, so that the combined pixels corresponding to the spots reflected by objects at different distances within the measurement range all fall into the superpixel area. In some embodiments, the reflected light spot is imaged to one side of the superpixel (left or right, depending on the relative position of the emitter and collector) when the target is at the minimum range, and when the target is at the maximum range When the reflected light spot is imaged to the other side of the superpixel.

As an embodiment of the present application, an off-axis scanning distance measurement method is also provided. Referring to FIG. 6 , the control method includes the following steps:

S10. Control the sub-light source arrays in the transmitter to be turned on one by one along the baseline direction, and emit spot light beams toward the target field of view;

Wherein, the transmitter includes a light source array composed of a plurality of light sources, and the light source array includes a plurality of the sub-light source arrays.

S20, controlling the activation of pixels in the sub-pixel array of the collector to collect photons in the reflected speckle beam, and form a photon signal;

Wherein, the collector includes a pixel array composed of a plurality of pixels, and the pixel array includes a plurality of the sub-pixel arrays.

The processing circuit is configured to include a plurality of sub-processing circuits, and each sub-pixel array is connected to each sub-processing circuit in a one-to-one correspondence. When any pixel in the sub-pixel array receives a photon and generates a photon signal, the sub-processing circuit can calculate the Get the time of flight corresponding to the photon signal.

Specifically, as shown in FIG. 2 and FIG. 3 , in the first measurement stage, the first sub-light source array 211 emits 5 spot beams. For the spot beam 213 considering the influence of parallax, the first sub-beam corresponding to the spot beam 213 In the pixel array 311, the super pixel 313 is turned on to collect the reflected light beam. Assuming that the reflected light beam is imaged on the combined pixel 315, the first sub-processing circuit 323 is used to calculate the flight time of the speckle light beam 213; in the second measurement stage, the second sub-light source The array 212 emits 5 spot light beams. Considering the influence of parallax for the spot light beam 214, the corresponding first sub-pixel array 311 opens the super pixel 314 for collecting the reflected light beam. Assuming that the reflected light beam is imaged on the combined pixel 316, the first The sub-processing circuit 323 is used to calculate the time of flight of the speckle beam 214 . Until all sub-light source arrays are activated, the scanning distance measurement of the target field of view is completed. During the scanning measurement process, the sub-light source arrays are turned on one by one along the y direction to emit light beams. The light beams emitted by the light sources in the same column in the light source array are all incident on some pixels in the same sub-pixel array, and the same sub-processing circuit calculates the flight of the beam. time. The working modes of other sub-pixel arrays are the same, and are not repeated here. It can be understood that the position of the superpixel corresponding to each light spot can be pre-calibrated and stored in the memory for recall when the system performs distance measurement.

FIG. 4 is a schematic diagram of a projected speckle pattern in an embodiment of the present application. In this embodiment, the transmitter 11 includes a light source array 21 and a diffractive optical element (not shown). The diffractive optical element is used for duplicating the spot beam emitted by the light source array 21 and projecting it into the target field of view to form multiple projection spots, and the spot beam reflected by the target is received by the collector 12 .

In some embodiments, with reference to FIG. 2 and FIG. 4 , a dual-line scanning distance measurement system is further proposed. The spot beam projected by the light source array 21 is replicated by the diffractive optical element, and the quantity of the spot beam projected to the target field of view is regulated by designing the diffractive optical element design process.

In some embodiments, the spot beam projected by the light source array 21 is replicated in the y-direction through diffractive optical elements into -1 order, 0 order, and 1 order, and there is a 50% overlap between the two adjacent orders, resulting in the middle 0 order being Therefore, in the y direction, the number of spot beams emitted by the light source array 21 is twice as large, and in the x direction, any series can be reproduced without overlapping between adjacent ones, for example, in the x direction, it can also be reproduced as - Level 1, Level 0, Level 1, the number of duplicated spots is 3 times the original. The speckle projection pattern projected to the target field of view based on this design is shown in Fig. 4, including 8 × 15 speckles. When the driving circuit controls the first sub-light source column 211 to emit five spot light beams, they are copied by the diffractive optical element and then projected into the target field of view to form two sets of

spot projection patterns

41 and 42 to scan the two areas in the target field of view synchronously Thus, the target field of view is divided into upper and lower field of view areas, which are respectively denoted as the first field of view and the second field of view. The number of spot beams enables simultaneous scanning of both fields of view.

FIG. 5 is a schematic diagram of a pixel unit according to another embodiment of the present application. The pixel unit includes a pixel array and a processing circuit, wherein the pixel array is divided into upper and lower regions, denoted as a first pixel array 51 and a second pixel array 52 respectively, and the first and

second pixel arrays

51 and 52 respectively include a plurality of sub-regions.

Pixel arrays

511 and 521; wherein, the first and second pixel arrays respectively collect photons in the spot light beams reflected back from the first and second fields of view and form photon signals. The processing circuits are correspondingly divided into a first processing circuit 53 and a second processing circuit 54, and each processing circuit includes a plurality of

sub-processing circuits

533 and 544; The first pixel array and the second pixel array are connected in a one-to-one correspondence, and are used for receiving the photon signals output by the pixels in the corresponding sub-pixel array and calculating the flight time of the light beam. The number of sub-pixel arrays is determined by the number of spot beams projected onto the field of view in a single measurement.

It can be understood that the configurations of the first and second sub-pixel circuits and the first and second processing circuits are the same. The specific working mode is the same as the working mode of the embodiment shown in FIG. 3. The sub-light source array is controlled to be turned on one by one along the baseline direction to emit spot beams toward the target field of view; The photon in the speckle beam is generated and the photon signal is output; the sub-processing circuit is used to receive the photon signal output by the corresponding sub-pixel array, and the flight time of the speckle beam from being emitted to being collected is calculated according to the photon signal. The difference is that, in the embodiment shown in FIG. 4 , when a sub-light source array is turned on in each measurement stage, the spot beams emitted by the sub-light source arrays are replicated by diffractive optical elements to generate two groups of spot beams. For example, in the first measurement stage, the first sub-light source array 211 emits 5 spot light beams, and after being replicated by the diffractive optical element, two sets of spot light beams 41 and 42 are projected toward the target field of view to the first field of view and the second field of view, respectively. Field, each group of 15 spots, the spot beam reflected by the target is imaged into the corresponding first and second pixel arrays, and the superpixel corresponding to the spot is turned on in the sub-pixel array to collect photons in the reflected beam. The specific method As mentioned above, details are not repeated here.

It can be understood that, in some embodiments, the light source array 21 includes 4×5 light sources, and 8×15 spot beams are projected toward the target area after being replicated by the diffractive element, and the corresponding pixel array needs to be set to include 16×30 pixels, The pixel array is configured to include 30 sub-pixel arrays, and 30 TDC circuits are correspondingly connected for calculating the flight time. In the existing solution, it is usually necessary to set one combined pixel to share one TDC circuit, and 120 TDC circuits need to be set. Therefore, the number of TDC circuits can be greatly reduced through the design of this embodiment. That is, the light source array includes n sub-light source arrays that are turned on one by one to scan the field of view, so that the number of TDC circuits and histogram circuits can be reduced to 1/n. What is shown in FIG. 5 is for illustrative reference only, and the number thereof is not limiting.

According to the description of the above embodiments, when designing the system, light sources can be arranged at small intervals in the y direction (baseline direction) to fully improve the angular resolution, and all the light sources in the y direction share the same sub-pixel array, and the sub-pixel array The length can completely cover the parallax, so the requirements for the baseline can be relaxed, the number of ranging points can be increased, and the spatial resolution can be improved. Due to the dense arrangement of light sources in the y direction, the superpixels corresponding to the projected spot beams overlap, but the successive scanning method is adopted to solve the problem of superpixel overlap and improve the distance measurement accuracy. In the x-direction, the distance between the light sources can be increased to ensure that the beams emitted by each light source can be imaged on the corresponding sub-pixel array after reflection without errors caused by out-of-bounds situations, so the tolerances can be relaxed. Require. In addition, the readout circuit and the pixel array are designed on the same plane, which reduces the number of TDC circuits and histogram circuits, and effectively reduces the process cost and complexity.

It can be understood that, the descriptions of the above embodiments are described by taking the baseline direction as the y direction as an example for description. In some other embodiments, the baseline direction can also be set as the x direction, and the sub-light source array includes a row of sub-light sources. , and the sub-pixel array includes at least one row of pixels.

An embodiment of the present application further provides a storage medium for storing a computer program, when the computer program is executed, at least the distance measurement method described in the foregoing embodiments is executed.

The storage medium may be implemented by any type of volatile or non-volatile storage device, or a combination thereof. Among them, the non-volatile memory can be a read-only memory (ROM, Read Only Memory), a programmable read-only memory (PROM, Programmable Read-Only Memory), an erasable programmable read-only memory (EPROM, Erasable Programmable Read-Only Memory) Memory), Electrically Erasable Programmable Read-Only Memory (EEPROM, Electrically Erasable Programmable Read-Only Memory), Magnetic Random Access Memory (FRAM, Ferromagnetic Random Access Memory), Flash Memory (Flash Memory), Magnetic Surface Memory, Optical Disc, Or compact disc read-only memory (CD-ROM, Compact Disc Read-Only Memory); magnetic surface memory can be magnetic disk memory or tape memory. Volatile memory may be Random Access Memory (RAM), which acts as an external cache. By way of example and not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), SynchronousStatic Random Access Memory (SSRAM), Dynamic Random Access Memory (DRAM, Dynamic Random Access Memory), Synchronous Dynamic Random Access Memory (SDRAM, Synchronous Dynamic Random Access Memory), Double Data Rate Synchronous Dynamic Random Access Memory (DDRSDRAM, Double Data Rate Synchronous Dynamic Random Access Memory), Enhanced Synchronous Dynamic Random Access Memory Access memory (ESDRAM, Enhanced Synchronous Dynamic Random Access Memory), synchronous connection dynamic random access memory (SLDRAM, SyncLink Dynamic Random Access Memory), direct memory bus random access memory (DRRAM, Direct Rambus Random Access Memory). The storage medium described in the embodiments of the present application is intended to include but not limited to these and any other suitable types of memory.

Embodiments of the present application further provide a computer device, the computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor; wherein the processor executes the computer During the program, at least the distance measurement method described in the foregoing embodiments is implemented.

It can be understood that the above content is a further detailed description of the present application in conjunction with specific/preferred embodiments, and it cannot be considered that the specific implementation of the present application is limited to these descriptions. For those of ordinary skill in the technical field of the present application, without departing from the concept of the present application, they can also make several substitutions or modifications to the described embodiments, and these substitutions or modifications should be regarded as It belongs to the protection scope of this application. In the description of this specification, reference to the terms "one embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples" or the like is meant to be used in conjunction with the description. A particular feature, structure, material, or characteristic described by an example or example is included in at least one embodiment or example of the present application.

In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other. Although the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope as defined by the appended claims.

Furthermore, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. Those of ordinary skill in the art will readily appreciate that the above disclosures, processes, machines, now existing or later developed, that perform substantially the same functions or achieve substantially the same results as the corresponding embodiments described herein can be utilized. Manufacture, composition of matter, means, method or step. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

A distance measurement system is characterized in that: it comprises a transmitter and a collector arranged along a baseline, and a processing circuit connected with the transmitter and the collector; wherein,

The transmitter includes a light source array composed of a plurality of light sources, the light source array includes a plurality of sub-light source arrays, and the sub-light source arrays are configured to be turned on one by one along the baseline direction for emitting spot light beams;

The collector includes a pixel array composed of a plurality of pixels, the pixel array includes a plurality of sub-pixel arrays, and the plurality of sub-pixel arrays are configured to collect the speckle beam reflected back by the target object to be measured. photons and form photon signals;

The processing circuit includes a plurality of sub-processing circuits, and the sub-processing circuits are connected to the sub-pixel array in one-to-one correspondence, so as to control the pixels in the sub-pixel array to activate for collecting photons in the reflected light beam, and according to the The photon signal output by the sub-pixel array calculates the time-of-flight of the speckle beam from emission to reflection back to being collected.
The distance measurement system according to claim 1, wherein: the sub-light source array comprises a row or a column of light sources; the sub-light source array is activated one by one under the control of a driving circuit to project the spot beam to the target viewing area Field; in which, only one sub-light source array is activated in one measurement stage, until all sub-light source arrays are activated, the scanning of the entire target field of view is completed.
The distance measurement system according to claim 2, wherein the scanning direction of the light source array is the same as the baseline direction.
The distance measurement system according to claim 1, wherein the pixel array and the processing circuit are arranged in the same plane.
The distance measurement system according to claim 1, further comprising a diffractive optical element, and the spot beam emitted by the sub-light source array is copied by the diffractive optical element and projected into the target field of view to form two sets of spot projections pattern to simultaneously scan two areas in the target's field of view.
The distance measurement system according to claim 5, wherein: the pixel array is divided into a first pixel array and a second pixel array, each pixel array includes a plurality of the sub-pixel arrays; the processing circuit corresponds to the pixel array It is a first processing circuit and a second processing circuit, and each processing circuit includes a plurality of the sub-processing circuits; the first processing circuit and the second processing circuit are respectively arranged on both sides of the pixel array and are respectively connected with each other. The first pixel array and the second pixel array are connected in one-to-one correspondence, and are used for receiving photon signals output by pixels in the corresponding sub-pixel array and calculating the flight time of the light beam.
A method for measuring distance, comprising the steps of:

S10. Control the sub-light source arrays in the transmitter to be turned on one by one, and emit spot light beams toward the target field of view; wherein, the transmitter includes a light source array composed of a plurality of light sources, and the light source array includes a plurality of the sub-light source arrays;

S20. Control the activation of the pixels in the sub-pixel array of the collector to collect photons in the reflected speckle beam, and form a photon signal; wherein the collector includes a pixel array composed of a plurality of pixels, and the pixels an array including a plurality of the sub-pixel arrays;

S30. Use the sub-processing circuit in the processing circuit to receive the photon signal output by the corresponding sub-pixel array, and calculate the time-of-flight of the speckle beam from being emitted to being collected according to the photon signal.
The distance measurement method according to claim 7, wherein: the processing circuit is configured to include a plurality of the sub-processing circuits; wherein, the sub-pixel array is connected to the sub-processing circuits in a one-to-one correspondence.
The distance measurement method according to claim 8, characterized in that: in step S10, the sub-light source arrays are turned on one by one along the baseline direction to emit spot beams, until all the sub-light source arrays are activated, and the scanning of the target field of view is completed; Wherein, the spot light beams emitted by the light sources in the same column/or the same row in the light source array are all incident on some pixels in the same sub-pixel array, and the flight time of the light beams is calculated by the same sub-processing circuit.
A computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor; wherein, when the processor executes the computer program, at least one A distance measurement method; the distance measurement method includes the steps: S10, controlling the sub-light source arrays in the transmitter to be turned on one by one, and emitting spot light beams toward the target field of view; wherein, the transmitter includes a light source array composed of a plurality of light sources, The light source array includes a plurality of the sub-light source arrays; S20, control the pixels in the sub-pixel array of the collector to start to collect photons in the reflected spot beams, and form a photon signal; wherein, the collector Including a pixel array composed of a plurality of pixels, and the pixel array includes a plurality of the sub-pixel arrays; S30. Use the sub-processing circuit in the processing circuit to receive the photon signal output by the corresponding sub-pixel array, and according to the The photon signal calculates the time-of-flight of the speckle beam from launch to acquisition.