A ranging system and a ranging method

Abstract

This application relates to the field of optical ranging technology, and more particularly to a ranging system and method. The ranging system includes: a transmitter, a collector, and a processing circuit; the transmitter includes a light source array composed of multiple columns of light sources; the collector includes a pixel array composed of multiple columns of pixels; the processing circuit controls at least two columns of light sources in the light source array to emit spot beams, and synchronously controls at least one column of pixels in the collector to turn on and collect the spot beams reflected by the target and output photon signals; the processing circuit calculates the distance information of the target based on the photon signals; wherein, the at least two columns of light sources include a parallax-free column light source and a parallax-positive column light source corresponding to the same column pixel in the at least one column of pixels. Embodiments of this application can solve near-range blind spots.

Description

Technical Field

[0001] This application relates to the field of optical ranging technology, and in particular to a ranging system and ranging method. Background Technology

[0002] The Time-of-Flight (TOF) principle is used to measure the distance to a target and obtain distance information. TOF-based ranging systems typically consist of a transmitter and a receiver. The transmitter emits a pulsed light beam to illuminate the target's field of view, and the receiver collects the reflected beam. The distance to the object is calculated by determining the time it takes for the beam to travel from emission to reflection and reception. TOF-based ranging systems, such as Time-of-Flight Depth Cameras (TOF-DLR) and Light Detection and Ranging (LIDAR) systems, are widely used in consumer electronics, robotics, autonomous vehicles, and AR / VR applications.

[0003] Among them, time-of-flight (TOF) based ranging systems mainly include mechanical ranging systems and solid-state ranging systems. Mechanical ranging systems achieve 360-degree wide-field-of-view distance measurement through a rotating base. Their transmitters are typically point or line light sources, characterized by concentrated beam intensity and high accuracy, but the longer scanning time results in a lower frame rate. Solid-state ranging systems, on the other hand, do not contain any moving mechanical parts. The emission field of view of the light source corresponds one-to-one with the acquisition field of view of the pixel; each light source emits a spot beam that is reflected and imaged onto the corresponding pixel after reaching the target's field of view.

[0004] Depending on the configuration of the transmitter and receiver, solid-state ranging systems are off-axis systems. Off-axis systems introduce blind spots during measurement. Due to the limited size of the combined pixels and the existence of system parallax and assembly tolerances, the light spot imaged onto the pixel array by the reflected beam can easily go out of bounds, resulting in the loss of ranging signals. Especially when the object being measured is close, the position of the light spot incident on the pixel array will shift away from the corresponding combined pixel, making it impossible to acquire a valid ranging signal.

[0005] The above background information is provided only to aid in understanding the inventive concept and technical solution of this application. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed before the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0006] The purpose of this application is to provide a ranging system and a ranging method to solve at least one of the problems mentioned in the background art.

[0007] To achieve the above objectives, the technical solution of this application embodiment is implemented as follows:

[0008] A ranging system includes: a transmitter, a data acquisition unit, and a processing circuit;

[0009] The transmitter includes a light source array consisting of multiple columns of light sources; at least two columns of light sources in the light source array emit spot beams.

[0010] The collector includes a pixel array consisting of multiple columns of pixels;

[0011] The processing circuit controls at least two columns of light sources in the light source array to emit spot beams, synchronously controls at least one column of pixels in the collector to turn on and collect the spot beams reflected by the target and output photon signals, and the processing circuit calculates the distance information of the target based on the photon signals;

[0012] The at least two column light sources include a parallax-free column light source and a parallax-containing column light source corresponding to the same column pixel in the at least one column pixel.

[0013] In some embodiments, the processing circuit further includes a readout circuit, which includes a time-distribution circuit (TDC) and a histogram circuit. The TDC circuit outputs a time signal based on the photon signal, and the histogram circuit generates a histogram based on the time signal.

[0014] In some embodiments, the processing circuit is configured to receive the photon signal, process it, generate a histogram, calculate the flight time of the spot beam from emission to acquisition based on the histogram, and calculate the distance information of the target based on the flight time.

[0015] In some embodiments, the processing circuit is connected to the transmitter and the collector.

[0016] In some embodiments, the parallax column light source among the at least two column light sources is turned on first, and the non-parallax column light source among the at least two column light sources is turned on later.

[0017] In some embodiments, the on-time of the parallax-enabled column light source among the at least two column light sources is less than the on-time of the non-parallax column light source among the at least two column light sources.

[0018] In some embodiments, the pulse period of the parallax-enabled column light source in the at least two column light sources is less than the pulse period of the non-parallax-enabled column light source in the at least two column light sources.

[0019] In some embodiments, pixels in the same row of the pixel array share a single readout circuit.

[0020] In some embodiments, the transmitter includes a plurality of the light source arrays;

[0021] The collector includes a plurality of pixel arrays that correspond one-to-one with the plurality of light source arrays;

[0022] The processing circuit controls at least two columns of light sources in each of the light source arrays to emit spot beams, and synchronously controls one column of pixels in each of the pixel arrays to turn on and collect the spot beams reflected by the target from the corresponding light source array and output photon signals. The processing circuit calculates the distance information of the target based on the photon signals.

[0023] Wherein, the at least two columns of light sources in each of the light source arrays include a column of light sources with parallax and a column of light sources with parallax corresponding to a column of pixels in the corresponding pixel array.

[0024] Another technical solution in this application embodiment is:

[0025] A ranging method, comprising:

[0026] Control at least two column light sources in the transmitter to emit spot beams;

[0027] At least one column of pixels in the synchronous control collector is activated and the spot beam reflected by the target is acquired and a photon signal is output.

[0028] The distance information of the target is calculated based on the photon signal;

[0029] The at least two column light sources include a parallax-free column light source and a parallax-containing column light source corresponding to the same column pixel in the at least one column pixel.

[0030] In some embodiments, calculating the distance information of the target based on the photon signal includes: receiving the photon signal, processing it, and outputting a histogram; calculating the flight time of the spot beam from emission to acquisition based on the histogram; and calculating the distance information of the target based on the flight time.

[0031] In some embodiments, the ranging method further includes: controlling the parallax column light source among the at least two column light sources to turn on first, and the non-parallax column light source among the at least two column light sources to turn on later.

[0032] In some embodiments, the ranging method further includes: controlling the on-time of the parallax-containing column light source among the at least two column light sources to be less than the on-time of the non-parallax column light source among the at least two column light sources.

[0033] In some embodiments, the ranging method further includes: controlling the pulse period of the parallax-containing column light source among the at least two column light sources to be less than the pulse period of the parallax-free column light source among the at least two column light sources.

[0034] Another technical solution in this application embodiment is:

[0035] An electronic device includes a ranging system as described in any of the above embodiments; the transmitter and the collector of the ranging system are disposed on the same side of the electronic device body.

[0036] The beneficial effects of the technical solution in this application are:

[0037] Compared to existing technologies, the embodiments of this application enable the emission of spot beams from a column of pixels corresponding to both a column of light sources with and without parallax, allowing the column of pixels to collect echo signals from both near and far distances. This solves the near-range blind zone and improves ranging accuracy. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of a ranging system provided in an embodiment of this application.

[0040] Figure 2A This is a schematic diagram of the parallax principle of a ranging system provided in an embodiment of this application.

[0041] Figure 2B This is a schematic diagram of the parallax principle of another ranging system provided in an embodiment of this application.

[0042] Figure 3 This is a schematic diagram of the structure of a ranging system provided in an embodiment of this application.

[0043] Figure 4 This is a schematic diagram illustrating the implementation process of a ranging method provided in an embodiment of this application.

[0044] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0045] To make the technical problems, technical solutions, and beneficial effects to be solved by the embodiments of this application clearer, 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 merely illustrative of this application and are not intended to limit this application.

[0046] The term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0047] The terms "one embodiment" or "some embodiments" described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0048] It should also be understood that, unless otherwise expressly specified or limited, the term "connection" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying 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 this application, "multiple" means two or more, unless otherwise explicitly specified.

[0050] Figure 1The diagram shows a distance measuring system according to an embodiment of this application. The distance measuring system 10 includes a transmitter 11, a collector 12, and a processing circuit 13. The transmitter 11 emits a beam 30 into a target area 20. The beam 30 illuminates the target object in the target area 20. At least a portion of the beam 30 is reflected by the target area 20 to form a reflected beam 40. At least a portion of the reflected beam 40 is received by the collector 12. The processing circuit 13 is connected to both the transmitter 11 and the collector 12, synchronizing the trigger signals of the transmitter 11 and the collector 12 to calculate the time required for the beam to travel from emission to reflection and reception, i.e., the flight time t between the emitted beam 30 and the reflected beam 40. Furthermore, the distance D between corresponding points on the target object can be calculated using the following formula (1):

[0051] D = c·t / 2 (1)

[0052] Where c is the speed of light.

[0053] In some embodiments, the transmitter 11 includes a light source 111, an emitting optical element 112, and a driver 113. The light source 111 can be a light-emitting diode (LED), a laser diode (LD), an edge-emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), or a one-dimensional or two-dimensional light source array composed of multiple light sources. Preferably, the light source array is a VCSEL array light source chip formed by generating multiple VCSEL light sources on a single semiconductor substrate. The arrangement of the light sources in the light source array can be regular or irregular. The light beam emitted by the light source 111 can be visible light, infrared light, ultraviolet light, etc. The light source 111 emits a light beam outward under the control of the driver 113.

[0054] In some embodiments, the light source 111 is configured as a light source array consisting of multiple light sources, wherein the light source array includes multiple column light sources or multiple row light sources, which can be referred to as multiple linear light sources. Each time, a linear light source is turned on, it emits a linear beam of light toward the target area until the last linear light source is turned on, thereby achieving scanning of the target area. The linear beam of light is formed by multiple light spots arranged sequentially, which can be spaced at a certain interval or connected sequentially. In other embodiments, the light source 111 is configured as consisting of multiple light source arrays, wherein each light source array is configured to include multiple light sources. Each of the multiple light source arrays simultaneously emits a linear beam of light toward the target area. The multiple linear beams project onto multiple linear projection patterns in the target area with a certain spacing to divide the target area into multiple regions, thereby achieving regional scanning of the target area.

[0055] In one embodiment, the light source 111 emits a pulsed light beam at a certain frequency (or pulse period) under the control of the driver 113 for direct time-of-flight (DTOF, dTOF) measurement, with the frequency set according to the measurement distance. It is understood that the light source 111 can also be controlled to emit the light beam using a portion of the processing circuitry 13 or a sub-circuit existing independently of the processing circuitry 13.

[0056] The emitting optical element 112 receives the light beam emitted from the light source 111, shapes it, and projects it onto the target area. In one embodiment, the emitting optical element 112 receives a pulsed light beam from the light source 111 and optically modulates the pulsed light beam, such as through diffraction, refraction, or reflection, and then emits the modulated light beam into space, such as a focused beam, a floodlight beam, or a structured light beam. The emitting optical element 112 can be one or more of the following forms: a lens, a liquid crystal element, a diffractive optical element, a microlens array, a metasurface optical element, a mask, a mirror, or a MEMS galvanometer.

[0057] In some embodiments, the collector 12 includes a pixel unit 121, a filtering unit 122, and a receiving optical element 123; wherein, the receiving optical element 123 is used to receive at least a portion of the light beam reflected back from the target object and guide the at least a portion of the light beam onto the pixel unit 121; the filtering unit 122 is used to filter out background light or stray light; the pixel unit 121 includes a one-dimensional or two-dimensional pixel array composed of multiple pixels. The pixel unit 121 is used to collect at least a portion of the light beam reflected back from 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), which can respond to an incident single photon and output a signal indicating the arrival time of the received photon at each SPAD, using a method such as time-correlated single-photon counting (TCSPC) to collect weak light signals and calculate the time of flight.

[0058] In some embodiments, the ranging system 10 further includes a readout circuit composed of one or more of the following devices: a signal amplifier, a TDC, and a digital-to-analog converter (ADC). Figure 1 (Not shown in the image). These readout circuits can be integrated with the processing circuit 13 and considered as part of the processing circuit 13. In one embodiment, the readout circuits receive photon signals and process them to generate a histogram.

[0059] The processing circuit 13 synchronizes the trigger signals of the transmitter 11 and the collector 12, processes the photon signals collected by the pixel unit 121, and calculates the distance information of the target object based on the flight time of the light beam from emission to reflection. In one embodiment, the SPAD responds to a single incident photon and outputs a photon signal. The processing circuit 13 receives the photon signal and performs signal processing to obtain the flight time of the light beam. Specifically, the processing circuit 13 calculates the number of collected photons to form continuous time bins. These time bins are linked together to form a statistical histogram for reproducing the time series of reflected light pulses. Peak matching and filtering detection are used to identify the flight time of the light beam from emission to reception. It is understood that the processing circuit 13 can be a standalone dedicated circuit, such as a dedicated SOC chip, FPGA chip, ASIC chip, etc., or it can contain general-purpose processing circuits.

[0060] In some embodiments, the ranging system 10 further includes a memory for storing a pulse coding program, which controls the excitation time, emission frequency, etc. of the light beam emitted by the light source 111.

[0061] In some embodiments, the ranging system 10 may also include devices such as a color camera, an infrared camera, and an IMU. Combining these devices can enable richer functions, such as 3D texture modeling, infrared face recognition, and SLAM.

[0062] It should be noted that, see Figure 2A The single-transmitter multiple-receiver principle diagram and Figure 2B The multi-transmitter single-receiver schematic diagram shown illustrates that, in some embodiments, the existence of a baseline between the transmitter and receiver in the ranging system causes the imaging position of the emitted light spot on the pixel unit to change with different target distances, a phenomenon known as parallax. Therefore, during column scanning ranging, only activating the pixel receiver corresponding to the light source will result in the inability to receive echo signals at certain distances, creating blind spots. Since the light spot offset caused by parallax is along the baseline direction, for ease of description, the baseline direction will be taken as horizontal in the subsequent embodiments, and the offset caused by parallax will be assumed to be from right to left. It should be noted that the offset direction is only illustrative and should not be construed as a limitation of the present invention. It should be understood that the exemplary description should not be interpreted as a limitation of this application; in other cases, the baseline direction may also be vertical (or perpendicular), etc.

[0063] In some embodiments, in a dTOF-based ranging system using SPADs as pixel arrays, the SPAD pixels are connected to readout circuits in the processing circuit, with each SPAD pixel corresponding to a readout circuit. The readout circuit includes a Time-of-Flight (TDC) circuit and a histogram circuit. The SPAD pixel responds to an incident single photon by outputting a photon signal. The TDC circuit receives the photon signal to generate a time signal, and the histogram circuit generates a histogram based on the time signal. Specifically, a single photon incident on a SPAD pixel will cause an avalanche. The SPAD pixel will output an avalanche signal to the TDC circuit, which then detects the time signal from the photon's emission from the transmitter to the avalanche. This time signal is used to find the corresponding time interval (bin) in the histogram circuit, incrementing the photon count within that time interval by 1. After multiple detections, the time bins are statistically analyzed using a histogram to reconstruct the waveform of the entire pulse signal, thus achieving accurate time-of-flight detection. Finally, the distance information of the target object is calculated based on the time of flight. Assuming the pulse period of the emitted pulse beam is T, and the maximum measurement range of the ranging system is D... max The corresponding maximum flight time is t1 = 2D max / c, generally requires T≥t1 to avoid signal confusion, where c is the speed of light. The histogram circuit is configured to include multiple time bins, the sum of which (denoted as the measurement time range of the histogram circuit) equals the pulse period T. Therefore, the number of time bins m = T / Δt, where Δt is the size of the time bin.

[0064] Figure 3 The diagram shown is a schematic representation of the light source array, pixel units, and processing circuitry in a ranging system according to an embodiment of this application. Figure 3 The left-middle figure is a schematic diagram of the structure of the light source array 31. Figure 3 The right-middle figure shows a schematic diagram of the pixel unit 32 and the processing circuit 33. Each light source in the light source array 31 corresponds one-to-one with each pixel (or combined pixel) in the pixel unit 32. The arrangement of the light sources can be regular or irregular, and correspondingly, the arrangement of the pixels can be regular or irregular. Figure 3 The image only shows an example of one regular arrangement.

[0065] The light source array 31 is configured as a two-dimensional light source array composed of multiple light sources disposed on a single or multiple substrates. It is understood that the light source array 31 includes multiple columns of light sources. In some embodiments, during a measurement phase of the ranging system, the light source array 31 emits a linear light source, which is formed by interconnecting the spot beams emitted by multiple light sources in a column. Preferably, the light source array 31 is an array of VCSEL chips composed of multiple VCSEL light sources disposed on a semiconductor substrate. The light sources in the light source array 31 can emit spot beams of any wavelength, such as visible light, infrared light, ultraviolet light, etc. In some embodiments, the light source array 31 can emit light under the modulation drive of a driving circuit, such as continuous wave modulation, pulse modulation, etc., and the light source array 31 can also emit light in groups under the control of the driving circuit. In some implementations, the driving circuit can be part of the processing circuit 33.

[0066] like Figure 3 As shown in the left-middle figure, the light source array 31 includes multiple columns of light sources, such as the first column of light source 1, the second column of light source 2, and the third column of light source 7. Each of the first column of light source 1, the second column of light source 2, and the third column of light source 7 includes multiple light sources (…). Figure 3 (A small box in the left-middle figure represents a light source). Multiple columns of light sources can be activated under the control of the driving circuit to project spot beams onto the target field of view. At least two columns of light sources are activated in a measurement phase until all columns of light sources are activated, completing the scanning of the entire target field of view. The scanning direction of the light source array 31 (i.e., the activation order of each column of light sources) is along the baseline direction. In this embodiment, the baseline direction is horizontal, so the light source array 31 is configured to include multiple 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 can be set on a separate substrate and controlled by different driving circuits to emit light in groups.

[0067] It should be noted that the specific configuration of the light source array depends on the baseline direction, which may include multiple columns or rows of light sources. When the baseline direction is horizontal, the light source array is configured to include multiple columns or rows of light sources; when the baseline direction is vertical, the light source array is configured to include multiple rows of light sources.

[0068] like Figure 3 As shown in the right-middle figure, pixel unit 32 includes a pixel array, specifically, a two-dimensional pixel array composed of multiple pixels. In this embodiment, the baseline direction is horizontal, and the pixel array is configured to include multiple columns of pixels or multiple columns of combined pixels. Figure 3In the right-hand diagram, a small box represents a pixel or a combined pixel. When the transmitter of the ranging system emits a speckled beam of light towards the target, the beam is reflected by the target, and the collector guides the beam to image onto the corresponding pixel or combined pixel. The light source and pixel (or combined pixel) of the ranging system correspond one-to-one. The size of the combined pixel can be specifically set according to the actual situation, but it must include at least one pixel. For ease of description, the following description uses one light source corresponding to one pixel as an example. The pixel array can include multiple columns of pixels, for example... Figure 3 The first column of pixels is 3, the second column is 4, the third column is 5, and the fourth column is 6. The processing circuit 33 includes a TDC circuit and a histogram circuit. Specifically, each pixel is connected to one TDC circuit and one histogram circuit, and the sum of multiple time bins in the histogram circuit equals T, meaning the measurement time range of the histogram circuit is T. It should be noted that when using merged pixels, preferably, each pixel in each merged pixel shares one TDC circuit and one histogram circuit, meaning they are connected to the same TDC circuit and histogram circuit.

[0069] Due to parallax in the ranging system, it is necessary to consider the imaging shift of the light spot caused by the varying distances of the target. Generally, the light spot will shift along the baseline direction. Combined with... Figure 2A and Figure 2B As shown, parallax in the ranging system primarily causes a shift in the beam reflected from near-range targets. In this embodiment, to overcome the blind spot in near-range measurement, multiple rows of light sources are configured to emit spot beams, and one row of pixels is activated to receive the spot beams reflected back from the multiple rows of light sources. This configured row of pixels is used to collect reflected beams from some light sources from targets at a greater distance (without parallax), and also to collect reflected beams from other light sources from targets at a closer distance (with parallax). In other words, the configured multiple rows of light sources include parallax-containing and parallax-free light sources corresponding to the columns of pixels. The parallax-free light sources are mainly used to project beams to targets at a greater distance from the system within the field of view, while the parallax-containing light sources are mainly used to project beams to targets at a closer distance from the system within the field of view.

[0070] See also Figure 3As shown, in the first measurement stage, the first column of light sources 1 and the second column of light sources 2 are activated to emit spot beams, and the first column of pixels 3 in the pixel array is activated to collect reflected light spots. Specifically, the first column of light sources 1 is the non-parallax column of light sources corresponding to the first column of pixels 3, and the second column of light sources 2 is the parallax column of light sources corresponding to the first column of pixels 3. That is, when the first column of light sources 1 emits spot beams, it projects them onto targets within the field of view that are at a relatively far distance and images the reflected beam onto the first column of pixels 3; when the second column of light sources 2 emits spot beams, it projects them onto targets within the field of view that are at a relatively close distance and images the reflected beam onto the first column of pixels 3.

[0071] In the second measurement phase, the second column of light sources 2 and the third column of light sources 7 are activated to emit spot beams, and the second column of pixels 4 in the pixel array is activated to collect reflected light spots. Specifically, the second column of light sources 2 is the non-parallax light source corresponding to the second column of pixels 4, and the third column of light sources 7 is the parallax light source corresponding to the second column of pixels 4. That is, when the second column of light sources 2 emits spot beams, it projects them onto targets within the field of view that are at a relatively far distance and images the reflected beam onto the second column of pixels 4; when the third column of light sources 7 emits spot beams, it projects them onto targets within the field of view that are at a relatively close distance and images the reflected beam onto the second column of pixels 4.

[0072] Each pixel in the pixel array is connected to a Time-Division Multiplexing (TDC) circuit and a histogram circuit. The sum of multiple time bins in the histogram circuit equals T, meaning the measurement time range of the histogram circuit is T. In a preferred embodiment, since the column pixels are turned on sequentially column by column, pixels in the same row of different columns can share a single TDC circuit and histogram circuit. For example, pixels in the same row of the first column (pixel 3), second column (pixel 4), third column (pixel 5), and fourth column (pixel 6) can share a single TDC circuit and histogram circuit, achieving time-division multiplexing of the TDC and histogram circuits, reducing power consumption and cost, and facilitating system miniaturization.

[0073] It should be noted that, in this embodiment, the number of column light sources corresponding to the deviation range caused by parallax is 2, which is used as an example description. It should be understood that this example description should not be construed as a specific limitation on the content of this application. The number of column light sources corresponding to the deviation range caused by parallax can be affected by the baseline size, ranging range, etc. of the system. In some embodiments, the number of column light sources corresponding to the deviation range caused by parallax can be determined by theoretical calculation or calibration methods.

[0074] exist Figure 3In the illustrated embodiment, two light sources respectively emit spot beams to targets located in the near-range and far-range of the acquisition field of view. Affected by factors such as target reflectivity and environmental temperature, there is an overlap in the projection ranges corresponding to the two light sources, making it impossible to determine which light source the measured signal corresponds to, and thus it is impossible to calculate the accurate three-dimensional coordinate data of the target. In some implementation manners, the ranging range that the far-range light source (parallax-free light source) can cover is from D01 to D02, where D01 < D02, and the ranging range that the adjacent near-range light source (parallax light source) can cover is from D11 to D12, where D11 < D12. Because there is an overlap in their ranging ranges, D12 > D01. As a non-limiting example, the measurement range of the near-range column light source is from 0 to 30 m, and the corresponding measurement time range in the histogram circuit is from 0 to 0.2 us, while the measurement range of the far-range column light source is from 15 m to 150 m, and the corresponding measurement time range in the histogram circuit is from 0.1 us to 1 us. When the flight time of the target is determined to be 0.18 us by resolving the histogram, it is impossible to determine which light source's projection field of view this flight time corresponds to, and thus the three-dimensional coordinate data of the target cannot be accurately obtained.

[0075] To address the problems existing in the above embodiment, in some other embodiments, multiple column light sources are controlled to emit sequentially and the column light sources are controlled to emit according to a preset time delay. The time delay t can be determined according to the measurement overlap range of the near-range and far-range column light sources. When configuring the histogram circuit, the measurement time range of the histogram circuit needs to be set as T + t. T is the measurement time range of the histogram circuit in the case without time delay.

[0076] As an implementation manner, first, control the near-range column light source (i.e., the parallax column light source) to emit a pulse, and after a time interval t ≥ (D12 - D01) / (2×c), control the far-range column light source (i.e., the parallax-free column light source) to emit a pulse, where c is the speed of light. This can eliminate the histogram aliasing between different emission columns. When more columns are turned on for emission, this manner can be extended for reference, which will not be elaborated here. Compared with the one-transmit-and-multiple-receive manner, in this implementation manner, the receiving column pixels are always on, so there is no switching blind area in the test results, and multiple emission triggers can be completed within one test pulse period while the consumption of TDC resources remains unchanged. The effect is better. In this implementation manner, the measurement time range of the histogram circuit is configured as T + t.

[0077] As a non-limiting example, continue to refer to Figure 3As shown, the first column of light sources 1 is the non-parallax column light source corresponding to the first column of pixels 3, and the second column of light sources 2 is the column light source with parallax corresponding to the first column of pixels 3. The third column of light sources 7 is the non-parallax column light source corresponding to the second column of pixels 4, and the fourth column of light sources 8 is the column light source with parallax corresponding to the second column of pixels 4. In the first measurement phase, the second column of light sources 2 is activated to emit a spot beam, and the first column of pixels 3 is activated to collect the reflected light spot from the second column of light sources 2. After a preset time interval t, the first column of light sources 1 is activated to emit a spot 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 phase, the third column of light sources 7 is activated to emit a spot beam, and the second column of pixels 4 is activated to collect the reflected light spot from the third column of light sources 7. After a preset time interval t, the second column of light sources 2 is activated to emit a spot beam, and the second column of pixels 4 collects the reflected light spot from the second column of light sources 2.

[0078] In some other embodiments, considering that the reflected signal energy of near points is stronger and the signal-to-noise ratio is higher, the activation time of near-distance column light sources (with parallax columns) can be significantly reduced during actual testing, thereby reducing the frame rate reduction caused by the activation of multiple columns of light sources.

[0079] In some embodiments, the frame rate can be kept constant by simultaneously reducing the on-time of the far-distance column light source and sacrificing some far-distance testing performance; in other embodiments, the on-time of the far-distance column light source can be kept constant and far-distance testing performance can be maintained by sacrificing some frame rate.

[0080] As a non-restrictive example, see further. Figure 3 As shown, the first column of light source 1 is the light source without parallax corresponding to the first column of pixel 3, and the second column of light source 2 is the light source with parallax corresponding to the first column of pixel 3.

[0081] For example, in the first measurement stage, the first column of light sources 1 and the second column of light sources 2 are turned on to emit spot beams, and the first column of pixels 3 is turned on to collect reflected light spots. The on-time of the first column of light sources 1 is h1, and the on-time of the second column of light sources 2 is h2, where h1>h2.

[0082] For example, in the first measurement stage, the second column of light sources 2 is turned on to emit spot beams, and the first column of pixels 3 is turned on to collect reflected light spots. The on-time of the second column of light sources 2 is h3. After a preset time interval t from when the second column of light sources 2 is turned on, the first column of light sources 1 is turned on to emit spot beams, and the first column of pixels 3 collects reflected light spots. The on-time of the first column of light sources 1 is h4. Where h3... <h4。

[0083] In some other embodiments, each column of light sources has a separate driving circuit. Considering that the reflected signal energy at close range is stronger and the signal-to-noise ratio is higher, the driving circuit can be used to dynamically adjust the period of the emitted pulse beam, thereby reducing the frame rate reduction caused by the activation of multiple columns of light sources.

[0084] Specifically, the period of the pulse beam emitted by the near-distance column light source (i.e., the column light source with parallax) can be dynamically controlled by the driving circuit to be shorter than that of the far-distance column light source (i.e., the column light source without parallax).

[0085] As a non-restrictive example, see further. Figure 3 As shown, the first column of light source 1 is the light source without parallax corresponding to the first column of pixel 3, and the second column of light source 2 is the light source with parallax corresponding to the first column of pixel 3.

[0086] 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 beams, and the first column of pixels 3 is turned on to collect reflected light spots. Both the first column of light sources 1 and the second column of light sources 2 emit pulse beams, but the period of the pulse beam emitted by the second column of light sources 2 is shorter than the period of the pulse beam emitted by the first column of light sources 1.

[0087] For example, in the first measurement stage, the second column of light sources 2 is turned on to emit spot beams, and the first column of pixels 3 is turned on to collect reflected light spots. After a preset time interval t between the activation of the second column of light sources 2, the first column of light sources 1 is turned on to emit spot beams, and the first column of pixels 3 collects reflected light spots. Both the first column of light sources 1 and the second column of light sources 2 emit pulse beams, and the period of the pulse beam emitted by the second column of light sources 2 is shorter than the period of the pulse beam emitted by the first column of light sources 1.

[0088] It should be noted that, in Figure 3 In the illustrated embodiment, the use of a single column of pixels receiving reflected light spots is described as an example. In other embodiments, a multi-column emission and multi-column reception method can also be adopted, that is, multiple columns of light sources are activated to emit spot beams, and multiple columns of pixels are activated to receive reflected light spots.

[0089] As a non-restrictive example, see further. Figure 3As shown, in the first measurement stage, activating the first column of light sources 1 and the second column of light sources 2 to emit spot beams allows for simultaneous activation and acquisition of reflected light spots by the first column of pixels 3 and the second column of pixels 4. For the first column of pixels 3, the first column of light sources 1 is a parallax-free column, while the second column of light sources 2 is a parallax-existing column; for the second column of pixels 4, the second column of light sources 2 is a parallax-free column. In the second measurement stage, activating the first column of light sources 2 and the second column of light sources 7 to emit spot beams allows for simultaneous activation and acquisition of reflected light spots by the second column of pixels 4 and the third column of pixels 5. For the second column of pixels 4, the second column of light sources 2 is a parallax-free column, while the third column of light sources 7 is a parallax-existing column; for the third column of pixels 5, the third column of light sources 7 is a parallax-free column.

[0090] It should also be noted that, in Figure 3 In the illustrated embodiment, single-line scanning is used as an exemplary description of the scanning method. In other embodiments, point-by-point scanning or multi-line scanning may also be used. It should be understood that the exemplary description should not be construed as a specific limitation on the content of this application.

[0091] In the point-by-point scanning method, multiple light sources are activated each time to emit spot beams, and the collector is simultaneously controlled to activate one pixel to receive the reflected light spot. The multiple light sources include a parallax light source and a non-parallax light source corresponding to one pixel.

[0092] The single-line scanning scenario has been described in detail in the foregoing embodiments; now, the multi-line scanning scenario will be described. The similarities between the multi-line scanning and single-line scanning embodiments will not be repeated here.

[0093] In a multi-line scanning embodiment, the transmitter includes multiple light source arrays, each configured as a one-dimensional or two-dimensional light source array composed of multiple light sources. Correspondingly, the collector includes multiple pixel arrays, each configured as a one-dimensional or two-dimensional pixel array composed of multiple pixels. Each pixel array corresponds one-to-one with one of the multiple light source arrays.

[0094] The specific structure of each light source array and its corresponding pixel array is as described above. Figure 3 The situation is the same in the illustrated embodiment.

[0095] To facilitate the description of the multi-line scanning embodiment, in one embodiment, an example is given where the transmitter includes three light source arrays and the collector includes three pixel arrays. The three light source arrays are a first light source array, a second light source array, and a third light source array; the three pixel arrays are 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. The first light source array and its corresponding first pixel array are used to scan the first region, the second light source array and its corresponding second pixel array are used to scan the second region, and the third light source array and its corresponding third pixel array are used to scan the third region. It should be understood that the scanning process for each region is the same as in the aforementioned single-line scanning embodiment.

[0096] To achieve segmented scanning of the target area, in the first stage of measurement, the first and second columns of light sources in each light source array are controlled to emit spot beams towards the target area. Simultaneously, the first column of pixels in each pixel array is activated. The first column of light sources corresponds to a parallax-free column, and the second column corresponds to a parallax-containing column. In the second stage of measurement, the second and third columns of light sources in each light source array are controlled to emit spot beams towards the target area, and so on. In the nth stage of measurement, the nth and (n+1th)th columns of light sources in each light source array are controlled to emit spot beams until the spot beam emitted by the last column of light sources in each light source array is received by the acquisition unit, completing one frame of measurement. It is understood that the above numerical descriptions are for illustrative purposes only and do not constitute a specific limitation on the content of this application. By configuring the area array light source system as an all-solid-state system, high reliability is achieved, and full field-of-view coverage is realized through dynamic switching of the line light sources at the transmitting end.

[0097] Figure 4 The diagram illustrates a ranging method according to another embodiment of this application. This ranging method can be applied to the ranging system of any of the foregoing embodiments. In some embodiments, the ranging method can be executed by the processing circuitry of the ranging system. In some embodiments, the ranging method can be executed by an electronic device.

[0098] like Figure 4 As shown, the ranging method may include the following steps S41 to S43.

[0099] S41 controls at least two columns of light sources in the light source array to emit spot beams.

[0100] S42, at least one column of pixels in the synchronous control collector is turned on and collects the spot beam reflected by the target and outputs photon signals.

[0101] S43 calculates the target's distance information based on the photon signal.

[0102] The at least two column light sources include a parallax-free column light source and a parallax-containing column light source corresponding to the same column pixel in the at least one column pixel.

[0103] In some embodiments, specifically, there are multiple light source arrays, and the collector includes multiple pixel arrays, with each of the multiple light source arrays corresponding to one of the multiple pixel arrays. Step S41 includes: controlling at least two columns of light sources in each light source array to emit spot beams; step S42 includes: synchronously controlling one column of pixels in each pixel array to turn on and collect the spot beams reflected by the target from the corresponding light source array and output photon signals.

[0104] In some embodiments, specifically, step S43 includes: receiving photon signals, processing them and generating a histogram, calculating the flight time of the spot beam from emission to acquisition based on the histogram, and calculating the distance information of the target object based on the flight time.

[0105] In some other embodiments, the ranging method further includes: controlling at least two columns of light sources to activate the parallax column light source first, and then activating it after the parallax column light source is absent from the at least two columns of light sources. That is, controlling at least two columns of light sources to emit a speckle beam first from the parallax column light source, and then emitting a speckle beam after the parallax column light source is absent from the at least two columns of light sources.

[0106] In some other embodiments, the ranging method further includes controlling the on-time of the parallax column light source among at least two column light sources to be less than the on-time of the non-parallax column light source among at least two column light sources. That is, the duration for which the parallax column light source emits a spot beam is less than the duration for which the non-parallax column light source emits a spot beam.

[0107] In some other embodiments, the ranging method further includes controlling the period of the pulse beam emitted by the parallax column light source in at least two column light sources to be less than the period of the pulse beam emitted by the non-parallax column light source in at least two column light sources.

[0108] It should be noted that the ranging method in this embodiment uses the ranging system of any of the aforementioned embodiments for ranging, and its technical solution is similar to that of the aforementioned ranging system, so it will not be repeated here.

[0109] It is understood that the above embodiments are for illustrative purposes only and should not be construed as limiting the scope of this application. In some other embodiments, the transmitter can also be controlled to emit a transverse linear beam of light that scans longitudinally. In some other embodiments, the light source array can also be a light source array of other combinations, for example, it can be a light source array formed by combining multiple sub-light sources into one light source using a beam combining element. In some embodiments, the sub-light source array can also be dynamically controlled to generate linear beams of different widths.

[0110] As another embodiment of this application, an electronic device is also provided, referring to Figure 5 As shown, the electronic device 500 includes: a processor 50, a memory 51, and a computer program 52 stored in the memory 51 and executable on the processor 50, such as a distance measurement program. When the processor 50 executes the computer program 52, it implements the steps in any of the above embodiments of the distance measurement method, for example... Figure 4 Steps S41 to S43 are shown.

[0111] For example, the computer program 52 may be divided into one or more modules / units, which are stored in the memory 51 and executed by the processor 50 to complete this application. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 52 in the electronic device 500.

[0112] Those skilled in the art will understand that Figure 5 This is merely an example of electronic device 500 and does not constitute a limitation on electronic device 500. Electronic device 500 may include more or fewer components than shown, or combine certain components, or different components. For example, electronic device 500 may also include input / output devices, network access devices, buses, etc.

[0113] The processor 50 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0114] The memory 51 can be an internal storage unit of the electronic device 500, such as a hard disk or RAM of the electronic device 500. The memory 51 can also be an external storage device of the electronic device 500, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the electronic device 500. Furthermore, the memory 51 can include both internal and external storage units of the electronic device 500. The memory 51 is used to store the computer program and other programs and data required by the electronic device. The memory 51 can also be used to temporarily store data that has been output or will be output.

[0115] In another embodiment of this application, an electronic device is provided, comprising the ranging system of any of the foregoing embodiments, wherein the transmitter and the collector of the ranging system are disposed on the same side of the electronic device body. In one embodiment, the ranging system is used to emit a light beam toward a target object and receive the light beam reflected back from the target object to form a photon signal, and calculate the distance information of the target object based on the photon signal.

[0116] As a non-limiting example, electronic devices may include optical measurement systems, such as lidar.

[0117] One embodiment of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps described in the various ranging method embodiments above.

[0118] One embodiment of this application provides a computer program product that, when run on an electronic device, enables the electronic device to implement the steps described in the various ranging method embodiments above.

[0119] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0120] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0121] In the embodiments provided in this application, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0122] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0123] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0124] If an integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, ROM, RAM, electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0125] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A ranging system, characterized in that, include: Transmitter, data collector, and processing circuitry; The transmitter includes a light source array consisting of multiple columns of light sources; The collector includes a pixel array consisting of multiple columns of pixels; The processing circuit controls at least two columns of light sources in the light source array to emit spot beams, synchronously controls at least one column of pixels in the collector to turn on and collect the spot beams emitted by the at least two columns of light sources reflected by the target and outputs photon signals. The processing circuit calculates the distance information of the target based on the photon signals. The at least two column light sources include a parallax-free column light source and a parallax column light source corresponding to the same column pixel in the at least one column pixel. The parallax-free column light source and the parallax column light source respectively project light beams to targets that are far from and near the ranging system within the field of view.

2. The ranging system as described in claim 1, characterized in that, The processing circuit further includes a readout circuit, which includes a TDC circuit and a histogram circuit. The TDC circuit outputs a time signal based on the photon signal, and the histogram circuit generates a histogram based on the time signal.

3. The ranging system as described in claim 1, characterized in that, The processing circuit is used to receive the photon signal, process it, and generate a histogram. Based on the histogram, it calculates the flight time of the spot beam from emission to acquisition, and calculates the distance information of the target based on the flight time.

4. The ranging system according to any one of claims 1 to 3, characterized in that, Of the at least two columns of light sources, the column light source with parallax is turned on first, and the column light source without parallax is turned on later.

5. The ranging system according to any one of claims 1 to 3, characterized in that, The on-time of the parallax-containing column light source among the at least two column light sources is less than the on-time of the non-parallax-containing column light source among the at least two column light sources.

6. The ranging system according to any one of claims 1 to 3, characterized in that, The pulse period of the parallax-containing column light source among the at least two column light sources is less than the pulse period of the parallax-free column light source among the at least two column light sources.

7. The ranging system as described in claim 2, characterized in that, Pixels in the same row of the pixel array share a single readout circuit.

8. The ranging system according to any one of claims 1 to 3, characterized in that, The transmitter includes multiple light source arrays; The collector includes a plurality of pixel arrays that correspond one-to-one with the plurality of light source arrays; The processing circuit controls at least two columns of light sources in each of the light source arrays to emit spot beams, and synchronously controls one column of pixels in each of the pixel arrays to turn on and collect the spot beams reflected by the target from the corresponding light source array and output photon signals. The processing circuit calculates the distance information of the target based on the photon signals. Wherein, the at least two columns of light sources in each of the light source arrays include a column of light sources with parallax and a column of light sources with parallax corresponding to a column of pixels in the corresponding pixel array.

9. A distance measurement method, characterized in that, include: Control at least two column light sources in the transmitter to emit spot beams; At least one column of pixels in the synchronous control collector is turned on and acquires the spot beam emitted by the at least two columns of light sources reflected by the target and outputs a photon signal; The distance information of the target is calculated based on the photon signal; The at least two column light sources include a parallax-free column light source and a parallax column light source corresponding to the same column pixel in the at least one column pixel. The parallax-free column light source and the parallax column light source respectively project light beams to targets that are far from and near the ranging system within the field of view.

10. An electronic device, characterized in that, The ranging system includes any one of claims 1 to 8, wherein the transmitter and the collector of the ranging system are located on the same side of the electronic device body.

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