CN113960569A

CN113960569A - Distance measuring system and distance measuring method

Info

Publication number: CN113960569A
Application number: CN202111216644.0A
Authority: CN
Inventors: 胡小龙; 张亦男; 闫敏
Original assignee: Shenzhen Oradar Technology Co Ltd
Current assignee: Shenzhen Oradar Technology Co Ltd
Priority date: 2021-10-19
Filing date: 2021-10-19
Publication date: 2022-01-21
Also published as: WO2023065589A1

Abstract

The present application relates to the technical field of optical ranging, and in particular, to a ranging system and a ranging method. The ranging system includes: an emitter, a collector and a processing circuit; the emitter includes a light source array composed of a plurality of columns of light sources; the collector includes a pixel array composed of a plurality of columns of pixels; the processing circuit controls At least two column light sources in the light source array emit speckle beams, and at least one column pixel in the collector is synchronously controlled to turn on and collect the speckle beams reflected by the target and output photon signals, and the processing circuit is based on the The photon signal calculates the distance information of the target; wherein, the at least two column light sources include a non-parallax column light source and a parallax column light source corresponding to the same column pixel of the at least one column pixel. The embodiments of the present application can solve the short-range blind spot.

Description

Distance measuring system and distance measuring method

Technical Field

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

Background

Distance measurement can be performed on the target using the Time of Flight (TOF) principle to obtain distance information including the target. Ranging systems based on the TOF principle typically include a transmitter and a collector, with the transmitter emitting a pulsed light beam to illuminate a target field of view and the collector collecting the reflected light beam, calculating the time required for the beam to be received from emission to reflection to calculate the distance to the object. Ranging systems based on TOF principles, such as time-of-flight depth cameras, LIDAR (Light Detection And Ranging) systems, have been widely used in the fields of consumer electronics, robotics, unmanned driving, AR/VR, And the like.

The ranging system based on the TOF principle mainly comprises a mechanical ranging system and a solid ranging system. The mechanical ranging system realizes distance measurement of a 360-degree large view field through a rotating base, and the emitters of the mechanical ranging system are generally point light sources and line light sources, so that the mechanical ranging system has the characteristics of concentrated light beam intensity and high precision, but the scanning time is longer, so that the frame rate is lower. The solid-state ranging system does not comprise movable mechanical parts, the emission visual field of the light sources and the collection visual field of the pixels have one-to-one correspondence, and each light source emits a spot light beam which is reflected and imaged on the corresponding pixel after reaching the target visual field.

According to the arrangement mode between the emitter and the collector, the solid-state ranging system belongs to an off-axis system, and the arrangement of the off-axis system causes the situation that a blind zone can be generated during measurement. Due to the limited size of the combined pixels and the existence of system parallax and assembly tolerance, the light spots imaged on the pixel array by the reflected light beams are easy to appear and lose the ranging signals. Especially, when the distance of the measured object is short, the position of the light spot incident on the pixel array can deviate and be far away from the corresponding combined pixel, and an effective ranging signal cannot be acquired.

The above background disclosure is only for the purpose of assisting in understanding the inventive concepts and technical solutions of the present application and does not necessarily belong to the prior art of the present patent application, and should not be used for evaluating the novelty and inventive step of the present application in the case that there is no clear evidence that the above contents are disclosed before the filing date of the present patent application.

Disclosure of Invention

An object of the present application is to provide a ranging system and a ranging method, so as to solve at least one of the above-mentioned problems in the background art.

In order to achieve the above purpose, the technical solution of the embodiment of the present application is implemented as follows:

a ranging system, comprising: the device comprises a transmitter, a collector and a processing circuit;

the emitter comprises a light source array consisting of a plurality of column light sources; at least two columns of light sources in the array of light sources emit spot beams;

the collector comprises a pixel array consisting of a plurality of columns of pixels;

the processing circuit controls at least two column light sources in the light source array to emit spot light beams, synchronously controls at least one column pixel in the collector to be started, collects the spot light beams reflected by a target and outputs photon signals, and the processing circuit calculates the distance information of the target according to the photon signals;

the at least two column light sources include a non-parallax column light source and a parallax column light source corresponding to the same column pixel in the at least one column pixel.

In some embodiments, the processing circuit further comprises a readout circuit comprising a TDC circuit that outputs a time signal from the photon signal and a histogram circuit that generates a histogram from the time signal.

In some embodiments, the processing circuit is configured to receive the photon signals for processing and generate a histogram, calculate a time of flight between emission and collection of the speckle beam based on the histogram, and calculate distance information of the target based on the time of flight.

In some embodiments, the processing circuit is connected to the transmitter and the collector.

In some embodiments, the parallax column light source of the at least two column light sources is turned on first, and the non-parallax column light source of the at least two column light sources is turned on later.

In some embodiments, the on-time of the parallax column light source of the at least two column light sources is less than the on-time of the parallax-free column light source of the at least two column light sources.

In some embodiments, a pulse period of the parallax column light source of the at least two column light sources is less than a pulse period of the non-parallax column light source of the at least two column light sources.

In some embodiments, pixels in the same row in the pixel array share one readout circuit.

In some embodiments, the emitter comprises a plurality of the arrays of light sources;

the collector comprises a plurality of pixel arrays corresponding to the light source arrays one by one;

the processing circuit controls at least two rows of light sources in each light source array to emit spot light beams, synchronously controls one row of pixels in each pixel array to be started, collects the spot light beams which come from the corresponding light source array and are reflected by a target and outputs photon signals, and the processing circuit calculates the distance information of the target according to the photon signals;

wherein the at least two column light sources in each light source array comprise a non-parallax column light source and a parallax column light source corresponding to the one column pixel in the corresponding pixel array.

Another technical solution of the embodiment of the present application is:

a method of ranging, comprising:

controlling at least two column light sources in the transmitter to emit spot beams;

synchronously controlling at least one column of pixels in the collector to be started, collecting the spot light beam reflected by the target and outputting a photon signal;

calculating distance information of the target according to the photon signals;

In some embodiments, calculating the range information of the target from the photon signals comprises: receiving the photon signals, processing and outputting a histogram, calculating the flight time of the spot light beams from emission to collection according to the histogram, and calculating the distance information of the target according to the flight time.

In some embodiments, the ranging method further comprises: and controlling the parallax column light sources in the at least two column light sources to be started first, and controlling the parallax-free column light sources in the at least two column light sources to be started later.

In some embodiments, the ranging method further comprises: and controlling the starting time length of the parallax column light source in the at least two column light sources to be smaller than the starting time length of the parallax-free column light source in the at least two column light sources.

In some embodiments, the ranging method further comprises: and controlling the pulse period of the parallax column light source in the at least two column light sources to be smaller than the pulse period of the parallax-free column light source in the at least two column light sources.

The embodiment of the application has the following further technical scheme:

an electronic device comprising the distance measuring system in any of the above embodiments; the emitter and the collector of the distance measuring system are arranged on the same side of the electronic equipment body.

The beneficial effects of this application technical scheme are:

compared with the prior art, the parallax column light source and the parallax-free column light source which correspond to one column of pixels are started to emit the spot light beams, so that the one column of pixels can acquire the echo signals at a short distance position and a long distance position, a short-distance blind area can be solved, and the ranging accuracy is improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without paying any creative effort.

Fig. 1 is a schematic structural diagram of a ranging system according to an embodiment of the present disclosure.

Fig. 2A is a schematic view of a parallax principle of a distance measuring system according to an embodiment of the present application.

Fig. 2B is a schematic view of a parallax principle of another distance measuring system according to an embodiment of the present application.

Fig. 3 is a schematic structural diagram of a ranging system according to an embodiment of the present disclosure.

Fig. 4 is a schematic flow chart illustrating an implementation of a ranging method according to an embodiment of the present application.

Fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the embodiments of the present application more clearly apparent, the present application is further described in detail below with reference to the accompanying drawings and the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

The term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather mean "one or more, but not all embodiments" unless specifically stated otherwise. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless expressly specified otherwise.

It is also to be understood that, unless expressly stated or limited otherwise, the term "coupled" is to be construed broadly, such as may be fixedly attached, removably attached, or integral; either directly or indirectly through intervening media, either internally or in any combination thereof. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

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

Fig. 1 is a schematic structural diagram of a ranging system according to an embodiment of the present disclosure, where the ranging system 10 includes a transmitter 11, a collector 12, and a processing circuit 13. Wherein, the emitter 11 is used for emitting the emission beam 30 to the target area 20, the emission beam 30 is emitted into the target area 20 to illuminate the target object in the space, at least part of the emission beam 30 forms a reflected beam 40 after being reflected by the target area 20, and at least part of the reflected beam 40 is received by the collector 12; the processing circuit 13 is connected to the emitter 11 and the collector 12, and synchronizes the trigger signals of the emitter 11 and the collector 12 to calculate the time required for the light beam to be received from emission to reflection, i.e. 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 (1):

D＝c·t/2 (1)

where c is the speed of light.

In some embodiments, the emitter 11 includes a light source 111, an emitting optical element 112, a driver 113, and the like. The light source 111 may be a Light Emitting Diode (LED), a Laser Diode (LD), an Edge Emitting Laser (EEL), a Vertical Cavity Surface Emitting Laser (VCSEL), or the like, or may be a one-dimensional or two-dimensional light source array composed of a plurality of light sources. Preferably, the light source array is a VCSEL array light source chip formed by generating a plurality of VCSEL light sources on a single semiconductor substrate, and the arrangement of the light sources in the light source array may be regular or irregular. The light beam emitted by the light source 111 may be visible light, infrared light, ultraviolet light, or the like. The light source 111 emits a light beam outward under the control of the driver 113.

In some embodiments, 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 column light sources or a plurality of row light sources, which may be referred to as a plurality of linear light sources, and each time one linear light source is turned on to emit one linear light beam toward the target area until the last linear light source is turned on, so as to scan the target area, wherein the linear light beam is formed by sequentially arranging a plurality of light spots, and may be arranged at certain intervals or sequentially connected. In other embodiments, the light source 111 is configured to be composed of a plurality of light source arrays, wherein each light source array is configured to include a plurality of light sources, the plurality of light source arrays each emit one linear light beam toward the target area at the same time, and the plurality of linear projection patterns projected into the target area by the plurality of linear light beams have a certain pitch to divide the target area into a plurality of areas, thereby realizing the sub-area scanning of the target area.

In one embodiment, the light source 111 emits a pulsed light beam outward under the control of the driver 113 at a frequency (or pulse period) for Direct time of flight (dTOF) measurement, the frequency being set according to the measurement distance. It will be appreciated that the light beam emitted by the light source 111 may also be controlled by a part of the processing circuitry 13 or a sub-circuit present independently of the processing circuitry 13.

The emission optical element 112 receives the light beam emitted from the light source 111 and projects the light beam to a target region after shaping. In one embodiment, the transmitting optical element 112 receives the pulsed light beam from the light source 111 and optically modulates, such as diffracting, refracting, reflecting, etc., the pulsed light beam, and then transmits the modulated light beam, such as a focused light beam, a flood light beam, a structured light beam, etc., into space. The emitting optical elements 112 may be in the form of one or more combinations of lenses, liquid crystal elements, diffractive optical elements, microlens arrays, super surface (Metasurface) optical elements, masks, mirrors, MEMS mirrors, and the like.

In some embodiments, collector 12 includes pixel cells 121, filter cells 122, and receiving optics 123; wherein the receiving optical element 123 is configured to receive at least a part of the light beam reflected by the target object and direct the at least a part of the light beam onto the pixel unit 121; the filtering unit 122 is used for filtering out background light or stray light; the pixel unit 121 includes a one-dimensional or two-dimensional pixel array composed of a plurality of pixels. The pixel unit 121 is used to collect at least part of the light beam reflected by the target object and generate a corresponding photon signal. In one embodiment, the pixel unit 121 is a pixel array composed of single photon avalanche photodiodes (SPADs) that can respond to incident single photons and output signals indicative of the respective arrival times of the received photons at each SPAD, the acquisition of the weak optical signals and the calculation of the time of flight are accomplished using methods such as time-correlated single photon counting (TCSPC).

In some embodiments, ranging system 10 further includes a readout circuit (not shown in FIG. 1) comprising one or more of a signal amplifier, a TDC, a digital-to-analog converter (ADC), and the like. These readout circuits may be integrated with the processing circuit 13 as part of the processing circuit 13. In one embodiment, the readout circuit receives the photon signal for processing to generate a histogram.

The processing circuit 13 synchronizes the trigger signals of the emitter 11 and the collector 12, processes the photon signals collected by the pixel unit 121, and calculates the distance information of the target object to be measured based on the flight time of the light beam from emission to reflection. In one embodiment, the SPAD outputs a photon signal in response to an incident single photon, and the processing circuitry 13 receives the photon signal and performs signal processing to obtain the time of flight of the beam. In particular, processing circuitry 13 counts the number of collected photons to form successive time bins, which together form a statistical histogram for reconstructing the time series of reflected light pulses, and identifies the time of flight of the light beam from emission to reception using peak matching and filtering detection. It will be appreciated that the processing circuit 13 may be a stand-alone dedicated circuit, such as a dedicated SOC chip, FPGA chip, ASIC chip, etc., or may comprise a general purpose processing circuit.

In some embodiments, the ranging system 10 further includes a memory for storing a pulse code program with which to control the excitation time, emission frequency, etc. of the light beam emitted by the light source 111.

In some embodiments, the ranging system 10 may further include devices such as color cameras, infrared cameras, IMUs, etc., and combinations thereof may implement more rich functions such as 3D texture modeling, infrared face recognition, SLAM, etc.

It should be noted that, referring to the single-transmission and multiple-reception schematic diagram shown in fig. 2A and the multiple-transmission and single-reception schematic diagram shown in fig. 2B, in some embodiments, due to the existence of the base line between the emitter and the collector in the ranging system, the imaging position of the emission spot of the light source on the pixel unit may change with the difference of the target distance, which is called parallax. Therefore, in the column scanning ranging process, only the pixels corresponding to the light source are turned on to receive the echo signals, and the echo signals at certain distances cannot be received, so that a blind area is formed. Since the spot shift due to parallax is along the baseline direction, for convenience of description, in the description of the subsequent embodiments, the baseline direction is taken as the horizontal direction, and the shift due to parallax is considered as a shift from right to left as an example for explanation. It should be noted that the offset direction is only schematically illustrated, and is not to be construed as a limitation on the present invention. It should be understood that the exemplary description is not to be construed as limiting the application, and in other cases, the direction of the base line may also be a vertical (or vertical) direction, etc.

In some embodiments, in a dOF-based ranging system with SPAD as a pixel array, SPAD pixels are connected with readout circuits in the processing circuit, and one readout circuit is connected to each SPAD pixelAnd (4) a way. The readout circuit comprises a TDC circuit and a histogram circuit, the SPAD pixel outputs a photon signal in response to an incident single photon, the TDC circuit is used for receiving the photon signal and generating a time signal, and the histogram circuit is used for generating a histogram according to the time signal. Specifically, a single photon is incident on the SPAD pixel to cause avalanche, the SPAD pixel outputs an avalanche signal to the TDC circuit, the TDC circuit detects a time signal from the emission of the photon to the occurrence of avalanche, the time signal is used for searching a corresponding time interval (bin) in the histogram circuit, so that the photon counting value in the time interval is added with 1, the time bin is subjected to histogram statistics after multiple detections to recover the waveform of the whole pulse signal, thereby realizing accurate flight time detection, and finally calculating the distance information of the target object according to the flight time. Assuming that the pulse period of the pulse beam emission is T, the maximum measurement range of the ranging system is D_maxThe corresponding maximum time of flight is t₁＝2D_maxC, general requirement T ≧ T₁To avoid signal aliasing, where c is the speed of light. The histogram circuit is configured to include a plurality of time bins, a sum of the plurality of time bins (denoted as a measurement time range of the histogram circuit) is equal to the pulse period T, and then the number m of the time bins is T/Δ T, and Δ T is a size of the time bin.

Fig. 3 is a schematic structural diagram of a light source array, a pixel unit and a processing circuit in a ranging system according to an embodiment of the present disclosure. The left diagram in fig. 3 is a schematic structural diagram of the light source array 31. The right image in fig. 3 is a schematic structural diagram of the pixel unit 32 and the processing circuit 33. Each light source in the light source array 31 corresponds to each pixel (or a combined pixel) in the pixel unit 32 one to one. The arrangement of the light sources may be regular or irregular, and correspondingly, the arrangement of the pixels may be regular or irregular, and fig. 3 only schematically illustrates an example of a regular arrangement.

The light source array 31 is configured as a two-dimensional light source array composed of a plurality of light sources disposed on a single-piece or multi-piece substrate. It will be appreciated that the array of light sources 31 comprises a plurality of columns of light sources. In some embodiments, during a measurement phase of the distance measuring system, the light source array 31 emits linear light sources, which are formed by connecting spot beams emitted by a plurality of light sources of a row of light sources. Preferably, the light source array 31 is an array VCSEL chip composed of a plurality of VCSEL light sources disposed on a semiconductor substrate. The light sources in the light source array 31 may emit a spot beam of any wavelength, such as visible light, infrared light, ultraviolet light, and the like. In some embodiments, the light source array 31 may emit light under modulation driving of the driving circuit, such as continuous wave modulation, pulse modulation, etc., and the light source array 31 may also emit light in groups under control of the driving circuit. In some implementations, the drive circuit may be part of the processing circuit 33.

As shown in the left diagram of fig. 3, the light source array 31 comprises a plurality of columns of light sources, for example a first column of light sources 1, a second column of light sources 2 and a third column of light sources 7. The first, second and third columns of light sources 1, 2, 7 each comprise a plurality of light sources (one small box shown on the left in fig. 3 represents one light source). The plurality of column light sources can be started under the control of the driving circuit to project the spot light beams to the target field of view, at least two column light sources are activated in one measuring stage, and the scanning of the whole target field of view is completed after all the column light sources are started; wherein the scanning direction of the light source array 31 (i.e. the activation sequence of the light sources in each column) is along the baseline direction. In the present embodiment, the baseline direction is the horizontal direction, and the light source array 31 is configured to include a plurality of columns of light sources, and the light source array is activated column by column in the horizontal direction (i.e., along the baseline direction) to complete one frame scan. In some implementations, each column of light sources may be disposed on a separate substrate, each controlled by a different driving circuit for group illumination.

It should be noted that the light source array specifically needs to include multiple columns of light sources or multiple rows of light sources according to the baseline direction, and when the baseline direction is the horizontal direction, the light source array is configured to include multiple columns of light sources or multiple columns of light sources; and when the baseline direction is a vertical (or perpendicular) direction, the light source array is configured to include a plurality of rows of light sources or a plurality of rows of light sources.

As shown in the right drawing in fig. 3, the pixel unit 32 includes a pixel array, specifically, a two-dimensional pixel array composed of a plurality of pixels. In the present embodiment, the baseline direction is a horizontal direction, and the pixel array is configured to include a plurality of columns of pixels or a plurality of columns of combined pixels (one small box shown in the right diagram in fig. 3 represents one pixel or one combined pixel). When the emitter of the ranging system emits the spot light beams to the target, the collector can guide the spot light beams to image on corresponding pixels or combined pixels after the spot light beams are reflected by the target, and light sources of the ranging system correspond to the pixels (or the combined pixels) one by one. The size of the combined pixel can be specifically set according to actual conditions, and the combined pixel at least comprises one pixel. For convenience of description, the present embodiment will be described below by taking one light source corresponding to one pixel as an example. The pixel array may include a plurality of columns of pixels, such as the first column of pixels 3, the second column of pixels 4, the third column of pixels 5, and the fourth column of pixels 6 shown in fig. 3. The processing circuit 33 includes a TDC circuit and a histogram circuit. Specifically, each pixel is connected with a TDC circuit and a histogram circuit, and the sum of a plurality of time bins in the histogram circuit is equal to T, i.e., the measurement time range of the histogram circuit is T. It should be noted that, when the combined pixels are used, it is preferable that each pixel in each combined pixel shares one TDC circuit and one histogram circuit, that is, the same TDC circuit and the same histogram circuit are correspondingly connected.

Due to the parallax in the ranging system, it is necessary to consider the situation that the light spot is subjected to imaging offset when the distance of the target is different, and generally, the light spot is offset along the baseline direction. As shown in fig. 2A and 2B, the parallax of the ranging system mainly causes the light beam reflected by the near target to shift. In the embodiment of the application, in order to overcome the short-distance measurement blind area, a plurality of columns of light sources are configured to emit spot light beams, and a column of pixels are started for receiving the reflected spot light beams from the plurality of columns of light sources. A column of pixels is arranged for collecting, on the one hand, reflected light beams from some light sources reflected by objects in a longer distance range (no parallax) and, on the other hand, reflected light beams from other light sources reflected by objects in a shorter distance range (parallax). That is, the arranged plural columns of light sources include parallax column light sources and non-parallax column light sources corresponding to the column pixels. The neutral column light sources are primarily used to project beams to targets in the field of view within a range of distances farther from the system, and the parallax column light sources are primarily used to project beams to targets in the field of view within a range of distances closer to the system.

With continued reference to fig. 3, during the first measurement phase, the first row of light sources 1 and the second row of light sources 2 are turned on to emit a spot beam, and the first row of pixels 3 of the pixel array is configured to be turned on and collect a reflected spot. The first row of light sources 1 is a non-parallax row of light sources corresponding to the first row of pixels 3, and the second row of light sources 2 is a parallax row of light sources corresponding to the first row of pixels 3. That is, when the first column light source 1 emits a spot light beam, a target located in a longer distance detection range within the field of view will be projected and the reflected light beam will be imaged to the first column of pixels 3; when the second column of light sources 2 emits a speckle beam, it will project onto a target within the field of view that is located within the closer detection range and image the reflected beam onto the first column of pixels 3.

In the second measurement phase, the second 2 and third 7 column light sources are turned on to emit a spot beam, the second pixel 4 of the pixel array is configured to be turned on and collect a reflected spot. The second row of light sources 2 is a non-parallax row of light sources corresponding to the second row of pixels 4, and the third row of light sources 7 is a parallax row of light sources corresponding to the second row of pixels 4. That is, when the second column of light sources 2 emits a speckle beam, a target located in a longer range of detection within the field of view will be projected and the reflected beam imaged to the second column of pixels 4; when the third column of light sources 7 emits a spot beam, it will project onto an object within the field of view that is located in the closer distance detection range and image the reflected beam onto the second column of pixels 4.

Each pixel of the pixel array is correspondingly connected with a TDC circuit and a histogram circuit, wherein the sum of a plurality of time bins in the histogram circuit is equal to T, namely the measurement time range of the histogram circuit is T. In a preferred embodiment, pixels in the same row in different columns of pixels may share one TDC circuit and one histogram circuit, since the column pixels are turned on sequentially column by column. For example, pixels in the same row in the first column of pixels 3, the second column of pixels 4, the third column of pixels 5, and the fourth column of pixels 6 may share one TDC circuit and one histogram circuit, so that time division multiplexing of the TDC circuit and the histogram circuit is achieved, power consumption and cost are reduced, and system miniaturization is facilitated.

It should be noted that, in the embodiment of the present application, the number of column light sources corresponding to the deviation range due to parallax is 2 columns as an exemplary description, and it should be understood that this exemplary description should not be construed as a specific limitation to the content of the present application. The number of column light sources corresponding to the range of the deviation due to parallax may be affected by the size of the baseline of the system, the range of the distance measurement, and the like. In some embodiments, the number of column light sources corresponding to the deviation range caused by the parallax can be determined by a theoretical calculation or calibration method.

In the embodiment shown in fig. 3, two light sources are used to emit spot beams for targets located at the near range and the far range, respectively, in the collection field of view. Due to the influence of factors such as target reflectivity, ambient temperature and the like, the projection ranges corresponding to the two light sources overlap, and it is impossible to determine which light source corresponds to the measured signal, and therefore accurate three-dimensional coordinate data of the target cannot be calculated. In some implementations, the distance light source (without parallax) emits ranging ranges that can be covered by D01-D02, D01< D02, and the adjacent near light source (with parallax) emits ranging ranges that can be covered by D11-D12, D11< D12, and since the ranging ranges of the two overlap, D12> D01. As a non-limiting example, the measurement range of the light source of the near column is 0 to 30m, the measurement time range of the corresponding histogram circuit is 0 to 0.2us, the measurement range of the light source of the far column is 15m to 150m, the measurement time range of the corresponding histogram circuit is 0.1us to 1us, when the time of flight of the target is determined to be 0.18us by calculating the histogram, it cannot be determined which light source corresponds to the time of flight, and the three-dimensional coordinate data of the target cannot be accurately acquired.

In some other embodiments, the plurality of column light sources are controlled to sequentially emit light and the column light sources are controlled to emit light according to a preset time delay. The time delay t can be determined according to the overlapping range of the near-far train light source measurement. It is necessary to set the measurement time range of the histogram circuit to T + T when configuring the histogram circuit. T is the measurement time range of the histogram circuit without time delay.

As one implementation, the short-range column illuminant (i.e., the parallax column illuminant) is first controlled to emit a pulse, and the long-range column illuminant (i.e., the non-parallax column illuminant) is controlled to emit a pulse after the time interval t ≧ (D12-D01)/(2 × c), where c is the speed of light. This eliminates aliasing of the histogram between different transmit columns. When more columns of transmission are turned on, the expansion can be performed in this way, which is not described herein again. Compared with a one-to-many receiving mode, the receiving column pixels are always opened in the implementation mode, so that a test result does not have a switching blind area, the triggering of multiple transmissions can be completed in one test pulse period, and meanwhile, the consumption of TDC resources is unchanged. The effect is better. In this implementation, the measurement time range of the histogram circuit is configured to be T + T.

As a non-limiting example, and with continued reference to fig. 3, the first row of light sources 1 is a non-parallax row of light sources corresponding to the first row of pixels 3, and the second row of light sources 2 is a parallax row of light sources corresponding to the first row of pixels 3. The second row of light sources 2 is a non-parallax row of light sources corresponding to the second row of pixels 4, and the third row of light sources 7 is a parallax row of light sources corresponding to the second row of pixels 4. In the first measurement stage, the second row of light sources 2 is started to emit spot light beams, and the first row of pixels 3 is started to collect reflected light spots from the second row of light sources 2; after a preset time interval t, the first column of light sources 1 is started to emit the spot light beam, and the first column of pixels 3 collects the reflected light spot from the first column of light sources 1. In the second measurement stage, the third row of light sources 7 is started to emit spot light beams, and the second row of pixels 4 is started to collect reflected light spots from the third row of light sources 7; after a preset time interval t, the second row of light sources 2 is turned on to emit the speckle beam, and the second row of pixels 4 collects the reflected speckle from the second row of light sources 2.

In other embodiments, considering that the reflected signal energy at the near point is stronger and the signal-to-noise ratio is higher, the turn-on time for the near-column light source (with parallax column) in the actual test process can be greatly reduced, thereby reducing the frame rate reduction caused by turning on the multiple columns of light sources.

At this time, in some embodiments, the frame frequency may be ensured to be unchanged by sacrificing a part of the remote test performance by simultaneously reducing the turn-on duration of the remote column light sources; in other embodiments, the remote row light source may be kept on for a fixed duration, while the remote test performance is maintained by sacrificing some frame rate.

As a non-limiting example, and with continued reference to fig. 3, the first row of light sources 1 is a non-parallax row of light sources corresponding to the first row of pixels 3, and the second row of light sources 2 is a parallax row of light sources corresponding to the first row of pixels 3.

For example, in the first measurement phase, the first column light source 1 and the second column light source 2 are turned on to emit spot beams, the first column pixel 3 is turned on to collect the reflected spot, the turn-on time of the first column light source 1 is h1, the turn-on time of the second column light source 2 is h2, and h1> h 2.

For another example, in the first measurement stage, the second row of light sources 2 is turned on first to emit the spot light beam, and the first row of pixels 3 is turned on to collect the reflected spot light at the same time, where the turn-on time of the second row of light sources 2 is h 3; after a preset time interval t from the turning on of the second row of light sources 2, the first row of light sources 1 is turned on again to emit spot light beams, the first row of pixels 3 collects reflected light spots, and the turning on duration of the first row of light sources 1 is h 4. Wherein h3< h 4.

In other embodiments, each column light source has a separate driving circuit, and considering that the reflected signal energy at a close point is stronger and the signal-to-noise ratio is higher, the period of emitting the pulse light beam can be dynamically regulated and controlled by using the driving circuit, so that the frame frequency reduction caused by the turn-on of the multiple columns of light sources is reduced.

Specifically, the driving circuit can be used to dynamically adjust the period of the pulse beam emitted by the near-distance column light source (i.e., the parallax column light source) to be shorter than that emitted by the far-distance column light source (i.e., the parallax-free column light source).

For example, in the first measurement phase, the first column of light sources 1 and the second column of light sources 2 are turned on to emit spot light beams, and the first column of pixels 3 is turned on to collect reflected spots. The first column light source 1 and the second column light source 2 both emit pulsed light beams, and the period of the pulsed light beams emitted by the second column light source 2 is shorter than the period of the pulsed light beams emitted by the first column light source 1.

For another example, in the first measurement stage, the second row of light sources 2 is turned on to emit a spot light beam, and the first row of pixels 3 is turned on to collect a reflected spot light; after a preset time interval t is reserved from the opening of the second row of light sources 2, the first row of light sources 1 is opened to emit spot light beams, and the first row of pixels 3 collect reflected spots. The first column light source 1 and the second column light source 2 both emit pulsed light beams, and the period of the second column light source 2 emitting the pulsed light beams is shorter than the period of the first column light source 1 emitting the pulsed light beams.

It should be noted that in the embodiment shown in fig. 3, a single column of pixels is turned on to receive the reflected light spot as an exemplary description. In other embodiments, a multi-column transmitting and multi-column receiving mode can be adopted, that is, a multi-column light source is turned on to emit a spot light beam, and a multi-column pixel is turned on to receive a reflected light spot.

As a non-limiting example, and with continued reference to fig. 3, during the first measurement phase, the first column of light sources 1 and the second column of light sources 2 are turned on to emit spot light beams, and the first column of pixels 3 and the second column of pixels 4 can be controlled to be turned on and collect reflected spots at the same time. For the first column of pixels 3, the first column of light sources 1 is a non-parallax column, and the second column of light sources 2 is a parallax column; for the second column of pixels 4, the second column of light sources 2 is a parallax-free column. In the second measurement phase, the first column of light sources 2 and the second column of light sources 7 are turned on to emit spot light beams, and the second column of pixels 4 and the third column of pixels 5 can be adjusted and controlled to be turned on simultaneously and collect reflected light spots. For the second column of pixels 4, the second column of light sources 2 is a non-parallax column and the third column of light sources 7 is a parallax column; for the third column of pixels 5, the third column of light sources 7 is a parallax-free column.

It should be further noted that, in the embodiment shown in fig. 3, a single line scan is taken as an exemplary description of the scanning manner. In other embodiments, a point-by-point scanning mode may be adopted, or a multi-line scanning mode may be adopted. It should be understood that the exemplary descriptions are not to be construed as specific limitations on the content of the present application.

In a point-by-point scanning mode, a plurality of light sources are started to emit spot light beams each time, and the collector is controlled to start one pixel to receive the reflected light spot, wherein the plurality of light sources comprise a parallax light source and a non-parallax light source corresponding to one pixel.

The case of the single line scanning is described in detail in the foregoing embodiment, and the case of the multi line scanning is now described. The multi-line scanning embodiment is the same as the single-line scanning embodiment, and is not described herein again.

In a multiline scanning embodiment, the emitter includes a plurality of light source arrays, each configured as a one-or two-dimensional light source array of a plurality of light sources. Correspondingly, the collector comprises a plurality of pixel arrays, and each pixel array is configured into a one-dimensional or two-dimensional pixel array consisting of a plurality of pixels. The plurality of pixel arrays correspond to the plurality of light source arrays one to one.

The specific structure of each light source array and its corresponding pixel array is the same as that of the embodiment shown in fig. 3.

For convenience in describing the multiline scanning embodiment, in one embodiment, the emitter includes 3 arrays of light sources and the collector includes 3 pixel arrays. The 3 light source arrays are respectively a first light source array, a second light source array and a third light source array; the 3 pixel arrays are respectively a first pixel array, a second pixel array and a third pixel array. In this embodiment, the target field of view is divided into three regions for scanning, a first light source array and a corresponding first pixel array for scanning the first region, a second light source array and a corresponding second pixel array for scanning the second region, and a third light source array and a corresponding third pixel array for scanning the third region. It will be appreciated that the scanning process for each region is the same as in the case of the single line scanning embodiment described previously.

In order to realize the regional scanning of the target region, in the first stage of measurement, a first row of light sources and a second row of light sources in each light source array are controlled to emit spot light beams to the target region, and simultaneously, each pixel array is controlled to start a first row of pixels, the first row of light sources are non-parallax rows corresponding to the first row of pixels, and the second row of light sources are parallax rows corresponding to the first row of pixels; and in the second stage of measurement, controlling the second column of light sources and the third column of light sources in each light source array to emit spot light beams to the target area, and so on, and in the nth stage of measurement, controlling the nth column of light sources and the (n + 1) th column of light sources in each light source array to emit spot light beams until the spot light beams emitted by the last column of light sources in each light source array are received by the collector, thereby completing one frame of measurement. It is to be understood that the above numerical descriptions are illustrative only and are not intended to be limiting upon the subject matter of the present application. The area array light source system is configured to be all solid, so that the reliability is high, and the full-view-field coverage is realized through the dynamic switching of the linear light source at the transmitting end.

Fig. 4 shows a ranging method according to another embodiment of the present application. The distance measuring method can be applied to the distance measuring system of any one of the embodiments. In some embodiments, the ranging method may be performed by processing circuitry of the ranging system. In some embodiments, the ranging method may be performed by an electronic device.

As shown in fig. 4, the ranging method may include the following steps S41 to S43.

And S41, controlling at least two columns of light sources in the light source array to emit spot light beams.

And S42, synchronously controlling at least one column pixel in the collector to be switched on, collecting the spot light beam reflected by the target and outputting a photon signal.

And S43, calculating the distance information of the target according to the photon signal.

In some embodiments, specifically, the light source array is multiple, the collector includes multiple pixel arrays, and the multiple light source arrays correspond to the multiple pixel arrays one to one. Step S41 includes: controlling at least two columns of light sources in each light source array to emit spot light beams; step S42 includes: and synchronously controlling one row of pixels in each pixel array to be started, collecting the spot light beams which come from the corresponding light source array and are reflected by the target, and outputting photon signals.

In some embodiments, in particular, step S43 includes: receiving the photon signals, processing the photon signals, generating a histogram, calculating the flight time from emission to collection of the spot light beams according to the histogram, and calculating the distance information of the target object based on the flight time.

In some other embodiments, the ranging method further comprises: and controlling the at least two row light sources to be started firstly when the row light source with parallax exists, and controlling the at least two row light sources to be started after the row light source without parallax exists. That is, the at least two row light sources are controlled to emit the speckle beams first by the parallax row light source and emit the speckle beams after the non-parallax row light source.

In some other embodiments, the ranging method further comprises: and controlling the starting time of the row light source with parallax in the at least two row light sources to be shorter than the starting time of the row light source without parallax in the at least two row light sources. That is, the time period during which the parallax column light source emits the speckle light beam is controlled to be shorter than the time period during which the non-parallax column light source emits the speckle light beam.

In some other embodiments, the ranging method further comprises: and controlling the period of the pulse light beam emitted by the parallax column light source in the at least two column light sources to be smaller than the period of the pulse light beam emitted by the parallax-free column light source in the at least two column light sources.

It should be noted that the distance measurement method of this embodiment adopts the distance measurement system of any one of the foregoing embodiments to perform distance measurement, and the technical solution thereof is similar to the foregoing distance measurement system, and therefore, the details are not repeated herein.

It is to be understood that the above examples are illustrative only and are not to be construed as limiting the present application. In other embodiments, the emitter may be controlled to emit a transverse line-shaped beam to scan along the longitudinal direction. In other embodiments, the light source array may also be a light source array in other combinations, for example, a light source array formed by combining a plurality of sub-light sources into one light source by using a beam combining element. In some embodiments, the sub-light source array may also be dynamically controlled to produce line-shaped light beams of different widths.

As another embodiment of the present application, there is also provided an electronic apparatus, as shown in fig. 5, an electronic apparatus 500 including: a processor 50, a memory 51 and a computer program 52, such as a program for distance measurement, stored in said memory 51 and executable on said processor 50. The processor 50, when executing the computer program 52, implements the steps in the ranging method embodiments of any of the above embodiments, such as the steps S41 to S43 shown in fig. 4.

Illustratively, the computer program 52 may be partitioned into one or more modules/units that are stored in the memory 51 and executed by the processor 50 to accomplish the present application. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, which are used to describe the execution of the computer program 52 in the electronic device 500.

Those skilled in the art will appreciate that fig. 5 is merely an example of the electronic device 500 and is not intended to limit the electronic device 500, that the electronic device 500 may include more or fewer components than shown, or that certain components may be combined, or that different components may be present, for example, the electronic device 500 may also include input-output devices, network access devices, buses, and the like.

The Processor 50 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The storage 51 may be an internal storage unit of the electronic device 500, such as a hard disk or a memory of the electronic device 500. The memory 51 may also be an external storage device of the electronic device 500, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like, provided on the electronic device 500. Further, the memory 51 may also include both an internal storage unit and an external storage device of the electronic device 500. The memory 51 is used for storing the computer program and other programs and data required by the electronic device. The memory 51 may also be used to temporarily store data that has been output or is to be output.

Another embodiment of the present application further provides an electronic device, where the electronic device includes the distance measuring system of any one of the foregoing embodiments, and the emitter and the collector of the distance measuring system are disposed on the same side of the electronic device body. In one embodiment, the ranging system is configured to emit a beam toward the target object and receive the beam reflected from the target object and form a photon signal, and calculate the distance information of the target object based on the photon signal.

As a non-limiting example, the electronic device may include an optical measurement system, such as a lidar or the like.

An embodiment of the present application provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the computer program can implement the steps in the embodiments of the ranging method described above.

An embodiment of the present application provides a computer program product, which when running on an electronic device, enables the electronic device to implement the steps in the foregoing ranging method embodiments.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described or recited in detail in a certain embodiment, reference may be made to the descriptions of other embodiments.

Those of ordinary skill in the art would appreciate that the elements and algorithm steps of the various embodiments described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus/electronic device and method may be implemented in other ways. For example, the above-described apparatus/electronic device embodiments are merely illustrative, and for example, a module or a unit may be divided into only one logical function, and an actual implementation may have another division, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

Units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated modules/units, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium. Based on such understanding, all or part of the flow in the method of the embodiments described above can be realized by a computer program, and the computer program can be stored in a computer readable storage medium, and when the computer program is executed by a processor, the steps of the embodiments of the methods described above can be realized. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer readable medium may include: any entity or device capable of carrying computer program code, recording medium, U-disk, removable hard disk, magnetic disk, optical disk, computer memory, ROM, RAM, electrical carrier wave signals, telecommunications signals, software distribution media, and the like. It should be noted that the computer readable medium may contain other components which may be suitably increased or decreased as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, in accordance with legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunications signals.

The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims

1. A ranging system, comprising: the device comprises a transmitter, a collector and a processing circuit;

the emitter comprises a light source array consisting of a plurality of column light sources;

2. The ranging system of claim 1, wherein the processing circuit further comprises a readout circuit comprising a TDC circuit and a histogram circuit, the TDC circuit outputting a time signal from the photon signal, the histogram circuit generating a histogram from the time signal.

3. The ranging system of claim 1, wherein the processing circuit is configured to receive the photon signals for processing and generate a histogram, calculate a time of flight of the speckle beam from emission to collection based on the histogram, and calculate range information for the target based on the time of flight.

4. A ranging system according to any of claims 1 to 3, wherein the parallax column light source of the at least two column light sources is turned on first and the parallax-free column light source of the at least two column light sources is turned on later.

5. A ranging system according to any of claims 1-3, wherein the duration of the activation of the parallax column light source of the at least two column light sources is less than the duration of the activation of the non-parallax column light source of the at least two column light sources.

6. A ranging system according to any of claims 1-3, wherein the period of pulses of the parallax column light source of the at least two column light sources is smaller than the period of pulses of the non-parallax column light source of the at least two column light sources.

7. The ranging system of claim 2, wherein pixels in a same row of the pixel array share a readout circuit.

8. The ranging system according to any of claims 1 to 3,

the emitter comprises a plurality of the light source arrays;

the processing circuit controls at least two columns of light sources in each light source array to emit spot light beams, synchronously controls one column of pixels in each pixel array to be started, collects the spot light beams which come from the corresponding light source array and are reflected by a target and outputs photon signals, and the processing circuit calculates the distance information of the target according to the photon signals;

9. A method of ranging, comprising:

synchronously controlling at least one column of pixels in the collector to be started, collecting the spot light beams reflected by the target and outputting photon signals;

calculating distance information of the target according to the photon signals;

10. An electronic device, comprising the distance measuring system as claimed in any one of claims 1 to 8, wherein the emitter and the collector of the distance measuring system are disposed on the same side of the electronic device body.