WO2020221185A1

WO2020221185A1 - Asynchronous tof discrete point cloud-based 3d imaging apparatus, and electronic device

Info

Publication number: WO2020221185A1
Application number: PCT/CN2020/087137
Authority: WO
Inventors: 吕方璐; 程世球
Original assignee: 深圳市光鉴科技有限公司
Priority date: 2019-04-30
Filing date: 2020-04-27
Publication date: 2020-11-05
Also published as: CN110221309A; CN110221309B

Abstract

An asynchronous ToF discrete point cloud-based 3D imaging apparatus, comprising: an asynchronous discrete light beam projector (2) sequentially projecting a plurality of discrete collimated light beams to different regions of a target object (3) in time order within a preset time period; and an optical detector array imager (1) sequentially receiving a plurality of discrete collimated light beams reflected by the target object (3) and measuring propagation time of the plurality of discrete collimated light beams, and then obtaining depth data of the plurality of regions of the target object (3), and generating depth data of the surface of the target object (3) according to the depth data of the plurality of regions of the target object (3). The invention can achieve the best accuracy and point cloud density for a specific 3D imaging application scenario, and can maintain a relatively low optical power each time a projection is performed, thereby satisfying the limitations to power consumption and laser for human eye safety.

Description

3D imaging device and electronic equipment based on asynchronous ToF discrete point cloud

Technical field

The present disclosure relates to the field of 3D imaging, and in particular, to a 3D imaging device and electronic equipment based on asynchronous ToF discrete point clouds.

Background technique

ToF (time of flight) technology is a technology that emits measurement light from the projector, and reflects the measurement light back to the receiver through the target object, so that the space from the object to the sensor can be obtained according to the propagation time of the measurement light in this propagation distance Distance 3D imaging technology. Commonly used ToF technology includes single point scanning projection method and surface light projection method.

The ToF method of single-point scanning projection uses a single-point projector to project a single beam of collimated light, and the projection direction of the single beam of collimated light is controlled by the scanning device to be able to project to different target positions. After the collimated light of the single beam is reflected by the target, part of the light is received by the single-point light detector, thereby obtaining the depth measurement data of the current projection direction. This method can concentrate all the optical power on a target point, thereby achieving a high signal-to-noise ratio at a single target point, and then achieving high-precision depth measurement. The scanning of the entire target object relies on scanning devices, such as mechanical motors, MEMS, and optical phase-controlled radars. Splicing the depth data points obtained by scanning can obtain the discrete point cloud data required for 3D imaging. This method is conducive to realizing long-distance 3D imaging, but requires the use of a complex projection scanning system, and the cost is relatively high.

The ToF method of surface light projection is to project a surface beam with continuous energy distribution. The projected light continuously covers the surface of the target object. The photodetector is an array of photodetectors that can obtain the travel time of the beam. When the light signal reflected by the target object is imaged on the light detector through the optical imaging system, the depth obtained by each detector image point is the depth information of the object position corresponding to the object image relationship. This method can get rid of complex scanning systems. However, since the optical power density of surface light projection is much lower than that of singular collimated light, the signal-to-noise ratio is greatly reduced compared to the single-point scanning projection method, so that this method can only be configured to reduce the distance and lower the accuracy. Scenes.

Summary of the invention

In view of the defects in the prior art, the purpose of the present disclosure is to provide a 3D imaging device and electronic equipment based on asynchronous ToF discrete point clouds. The present disclosure adopts an asynchronous discrete beam projection method, which can maintain a low optical power during each projection, and can meet the limitations of power consumption and laser eye safety.

The 3D imaging device based on asynchronous ToF discrete point cloud provided by the present disclosure includes an asynchronous discrete beam projector and a photodetector array imager;

The asynchronous discrete beam projector is configured to sequentially project multiple discrete collimated beams to different regions of the target object in a time sequence within a preset time period;

The photodetector array imager is configured to sequentially receive the multiple discrete collimated beams reflected by the target object and measure the propagation time of the multiple discrete collimated beams, so as to obtain the target The depth data of the multiple regions of the object is generated based on the depth data of the multiple regions of the target object.

Optionally, the asynchronous discrete beam projector includes an edge emitting laser and a beam projector arranged on an optical path;

The edge emitting laser is configured to project laser light to the beam projector;

The beam projector is configured to project a plurality of discrete collimated beams of the incident laser light sequentially to different regions of the target object in a time sequence within a preset time period.

Optionally, the asynchronous discrete beam projector includes a laser array, a collimating lens and a beam splitting device arranged on an optical path;

The laser array includes a plurality of lasers arranged in an array, and the plurality of lasers are divided into a plurality of laser emitting groups, and each laser emitting group is sent to the The collimating lens projects the first order of magnitude laser;

The collimating lens is configured to collimate the multiple incident laser beams and then emit a collimated beam of a first order of magnitude;

The beam splitting device is configured to split the incident collimated beam of the first order of magnitude and then emit the collimated beam of the second order of magnitude;

The second order of magnitude is greater than the first order of magnitude.

Optionally, the photodetector array imager includes an optical imaging lens, a photodetector array, and a driving circuit;

The photodetector array includes a plurality of photodetectors distributed in an array, and the plurality of photodetector emission groups are a plurality of photodetector groups, each of the photodetector groups and a laser emission group Corresponding;

The photodetector group is configured to receive the collimated light beam reflected by the target object after being emitted by the corresponding laser emitting group;

The optical imaging lens is configured such that the direction vector of the collimated light beam entering the photodetector array through the optical imaging lens has a one-to-one correspondence with the photodetector;

The driving circuit is configured to measure the propagation time of multiple discrete collimated light beams and then generate depth data of multiple regions on the surface of the target object, and then generate the depth data based on the depth data of multiple regions of the target object. Describe the depth data of the target surface.

Optionally, the multiple discrete collimated light beams are periodically arranged in a predetermined shape.

Optionally, the preset shape includes any of the following shapes or any multiple shapes that can be switched with each other:

-Straight

-triangle;

-quadrilateral;

-rectangle;

-Round;

-hexagon;

-Pentagon.

Optionally, the multiple discrete collimated beams are non-periodically arranged in another preset shape.

Optionally, the aperiodic arrangement includes any of the following arrangements or any multiple arrangements that can be switched between:

-Random arrangement;

-Space coding arrangement;

-Quasi-lattice arrangement.

Optionally, the asynchronous discrete beam projector includes multiple groups of edge-emitting lasers and beam projectors arranged on an optical path;

The edge-emitting laser is configured to project laser light to the beam projector; the beam projector is configured to project the incident laser light into multiple discrete collimated beams;

By sequentially controlling a group of edge-emitting lasers and beam projectors arranged on an optical path to turn on in the predetermined time period in a time sequence to project multiple discrete collimated beams to different regions of the target object.

The electronic equipment provided by the present disclosure includes the 3D imaging device based on asynchronous ToF discrete point clouds, and also includes a display panel; the asynchronous discrete beam projector and the photodetector array imager are located on the backlight side of the display panel ；

When the asynchronous discrete beam projector projects multiple discrete collimated light beams to different areas of the target object sequentially in time sequence within a preset time period, after the multiple discrete collimated light beams penetrate the display panel Shine on the target object;

The photodetector array imager receives multiple discrete collimated light beams that penetrate the display panel after being reflected by the target object, and obtains multiple discrete collimated light beams according to the propagation time of the multiple discrete collimated light beams. The depth data of the region, and then the depth data of the surface of the target object is generated according to the depth data of multiple regions of the target object.

Compared with the prior art, the present disclosure has the following beneficial effects:

The present disclosure uses an asynchronous discrete beam projector to project multiple discrete collimated beams to different regions of the target object in a time sequence within a preset time period, so that the photodetector array imager can obtain multiple regions of the target object The depth data of the target object is generated based on the depth data of multiple regions of the target object, which improves the beam power density and achieves a balance between the signal-to-noise ratio and the point cloud density, so as to achieve specific 3D Optimized accuracy and point cloud density in imaging application scenarios, and can maintain a low optical power during each projection, which can meet the limitations of power consumption and laser eye safety.

Description of the drawings

In order to explain the embodiments of the present disclosure or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are the embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on the provided drawings without creative work. By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, purposes and advantages of the present disclosure will become more apparent:

FIG. 1 is a schematic structural diagram of a 3D imaging device based on synchronized ToF discrete point clouds in an embodiment of the disclosure;

2 is a schematic diagram of a structure of an asynchronous discrete beam projector in an embodiment of the disclosure;

3 is a schematic diagram of another structure of an asynchronous discrete beam projector in an embodiment of the disclosure;

4 is a schematic structural diagram of an optical imaging lens in an embodiment of the disclosure;

5(a), (b), (c) are schematic diagrams of the periodic arrangement of multiple discrete collimated beams in an embodiment of the disclosure; and

6(a), (b), (c) are schematic diagrams of aperiodic arrangement of multiple discrete collimated beams in an embodiment of the disclosure.

In the picture:

1 is a photodetector array imager;

2 is an asynchronous discrete beam projector;

3 is the target object;

101 is a photodetector array;

102 is an optical imaging lens;

201 is an edge emitting laser;

202 is a beam projector;

203 is a laser array;

204 is a collimating lens;

205 is a beam splitting device.

Detailed ways

The disclosure will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present disclosure, but do not limit the present disclosure in any form. It should be pointed out that for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present disclosure. These all belong to the protection scope of the present disclosure.

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

It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top" The orientation or positional relationship indicated by "bottom", "inner", "outer", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, rather than indicating or imply The device or element must have a specific orientation, be configured and operate in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure.

In addition, the terms "first" and "second" are only configured for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the embodiments of the present disclosure, "plurality" means two or more than two, unless otherwise specifically defined.

In the present disclosure, the present disclosure provides a compromise solution between the single-point scanning projection method and the surface light projection method, that is, a projector is used to project multiple discrete collimated beams at the same time, which is paired with a ToF photodetector array, A synchronized 3D point cloud containing depth data of multiple target points can be obtained in a single measurement. According to actual application requirements, the number of collimated beams projected at the same time can range from a few to tens of thousands. The present disclosure can achieve the trade-off and optimization of the beam power density (i.e. signal-to-noise ratio) and the point cloud density by controlling the number of light beams under the same power. That is, when the number of beams is small, each point obtains higher signal-to-noise ratio and accuracy, but the point cloud is relatively sparse; when the number of beams is large, the point cloud is denser, but the signal-to-noise ratio and accuracy are relatively lower, but still excellent The method of surface light projection. In order to improve the accuracy and density of the point cloud at the same time, the present disclosure adopts an asynchronous projection method. The distribution of the beams projected each time is relatively sparse, and the distribution of the beams projected at different times is different, so as to obtain point cloud data of different regions of the target object. After the point clouds obtained by multiple projection measurements are stitched together, a relatively dense point cloud can be obtained. In this way, it is possible to achieve the most optimized accuracy and point cloud density for specific 3D imaging application scenarios, and to maintain a low optical power during each projection, so as to meet the limitations of power consumption and laser eye safety.

Figure 1 is a schematic structural diagram of a 3D imaging device based on a synchronous ToF discrete point cloud in the present disclosure. As shown in Figure 1, the 3D imaging device based on a synchronous ToF discrete point cloud provided by the present disclosure is configured to implement the asynchronous ToF based 3D imaging device provided by the present disclosure. 3D imaging device for ToF discrete point cloud, including asynchronous discrete beam projector 2 and photodetector array imager 1;

The asynchronous discrete beam projector 2 is configured to sequentially project multiple discrete collimated beams to different regions of the target object 3 in a time sequence within a preset time period;

The photodetector array imager 1 is configured to sequentially receive the multiple discrete collimated beams reflected by the target object 3 and measure the propagation time of the multiple discrete collimated beams, so as to obtain According to the depth data of the multiple regions of the target object 3, the depth data of the surface of the target object 3 is generated according to the depth data of the multiple regions of the target object 3.

In an embodiment of the present disclosure, the preset time period can be set to 10 milliseconds; the target object 3 includes at least a first area and a second area, so that it can be projected by asynchronous discrete beams within the preset time period A group of lasers in the device 2 first project multiple discrete collimated beams to the first area to obtain depth data of the first area, and then pass another group of lasers in the asynchronous discrete beam projector 2 to the second area. Multiple discrete collimated beams are projected into the area, the depth data of the second area is acquired, and the depth data of the surface of the target object 3 is generated according to the depth data of the first area and the depth data of the second area. The first area and the second area may be adjacent areas, or may be connected areas. The first area and the second area may also be intertwined. For example, the first area includes a plurality of randomly distributed first sub-areas, and the second area includes a plurality of randomly distributed first sub-areas at any gap between adjacent first sub-areas. The second sub-area. In the modified example, the target object 3 may include multiple regions, such as three regions, four regions, and so on.

In an embodiment of the present disclosure, within a plurality of the predetermined time periods, the asynchronous discrete beam projector 2 sequentially projects multiple discrete collimated beams to different regions of the target object 3 in a time sequence to generate A plurality of depth data on the surface of the target object 3 is further used to generate optimal depth data on the surface of the target object 3 iteratively according to the depth data on the surface of the target object 3.

In an embodiment of the present disclosure, the present disclosure uses the asynchronous discrete beam projector 2 to project multiple discrete collimated beams to different areas of the target object 3 in a time sequence within a preset time period, so that the photodetector array imager 1 It is possible to obtain the depth data of multiple regions of the target object 3, and generate the depth data of the surface of the target object 3 according to the depth data of the multiple regions of the target object 3, which improves the beam power density. A balance between point cloud density can be achieved to achieve the most optimized accuracy and point cloud density for specific 3D imaging application scenarios, and to maintain a low optical power during each projection, which can meet the power consumption and laser eyes Security restrictions.

The above is the core idea of the present disclosure. In order to make the above objectives, features, and advantages of the present disclosure more obvious and understandable, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Description, obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present disclosure.

In an embodiment of the present disclosure, the multiple discrete collimated beams in a discrete shape projected by the asynchronous discrete beam projector 2 are reflected by the target object 3, and the partially reflected collimated beams are received by the photodetector array 101. Each photodetector can obtain the flight time t of the corresponding beam from emission to reception, and obtain the flight distance s=ct of the collimated beam through the speed of light c, so as to measure the surface of each target object 3 illuminated by the discrete beam The depth information of the location. These discrete depth data points construct point cloud data that can reproduce the 3D shape of the object, so as to realize the 3D imaging of the target object 3. The plurality of discrete collimated light beams have a cone shape.

In an embodiment of the present disclosure, the number of the multiple discrete collimated beams is between two beams and tens of thousands of beams, such as 2 beams to 100,000 beams.

In an embodiment of the present disclosure, the 3D imaging device based on asynchronous ToF discrete point cloud provided by the present disclosure includes a driving circuit connected with the asynchronous discrete beam projector 2 and the photodetector array imager 1. The driving circuit is configured to control the asynchronous discrete beam projector 2 and the photodetector array imager 1 to be turned on or off at the same time.

The driving circuit can be an independent dedicated circuit, such as a dedicated SOC chip, FPGA chip, ASIC chip, etc., or a general-purpose processor, for example, when the depth camera is integrated into smart terminals such as mobile phones, TVs, computers, etc. , The processor in the terminal can be used as at least part of the processing circuit

FIG. 2 is a schematic structural diagram of the asynchronous discrete beam projector in the present disclosure. As shown in FIG. 2, the asynchronous discrete beam projector 2 includes an edge emitting laser 201 and a beam projector 202 arranged on an optical path;

The edge-emitting laser 201 is configured to project laser light to the beam projector 202;

The beam projector 202 is configured to project a plurality of discrete collimated beams of the incident laser light to different regions of the target object 3 sequentially in time sequence within a preset time period.

The beam projector 202 is provided with multiple sets of beam projection ports, and a set of beam projection ports are sequentially controlled in a chronological order within the predetermined period of time to project multiple beams of discrete collimation to different regions of the target object 3. beam. That is, within a preset time period, each group of beam projection ports is opened once to project multiple discrete collimated beams. When one group of beam projection ports is opened, the other groups of beam projection ports are closed. The opening and closing of the light beam projection port can be opened and closed by electromagnetic drive or micro-motor drive block.

In an embodiment of the present disclosure, the beam projector 202 can realize the function of dividing the incident light from the edge-emitting laser 201 into any number of collimated beams. The emission direction of the edge-emitting laser 201 and the emission direction of the beam projector 202 may be the same, or may be 90 degrees or any angle required for the design of the optical system.

In an embodiment of the present disclosure, because the inner surface of the beam splitting projector is processed with a micro-nano structure optical chip and is composed of an optical lens. The beam splitting projector can realize the function of dividing the incident light from the edge-emitting laser 201 into any number of collimated beams. The emission direction of the edge-emitting laser 201 and the projection direction of the beam splitting projector may be the same, or may be 90 degrees or any angle required for the design of the optical system.

In an embodiment of the present disclosure, the asynchronous discrete beam projector 2 includes multiple sets of edge emitting lasers 201 and beam projectors 202 arranged on an optical path;

The edge-emitting laser 201 is configured to project laser light to the beam projector 202; the beam projector 202 is configured to project the incident laser light into multiple discrete collimated beams;

In an embodiment of the present disclosure, a group of edge-emitting lasers 201 and beam projectors 202 arranged on an optical path are sequentially controlled in a chronological order within the predetermined period of time to turn on the target object 3. The area projects multiple discrete collimated beams. That is, within a preset period of time, each group of edge-emitting lasers 201 and beam projectors 202 set on an optical path are turned on once to project multiple discrete collimated beams. When the laser 201 and the beam projector 202 are turned on, the edge-emitting laser 201 and the beam projector 202 of the other groups arranged on an optical path are turned off.

FIG. 3 is a schematic diagram of another structure of the asynchronous discrete beam projector in this disclosure. As shown in FIG. 3, the asynchronous discrete beam projector 2 includes a laser array 203, a collimating lens 204, and a beam splitter arranged on an optical path. Device 205;

The laser array 203 includes a plurality of lasers arranged in an array, and the plurality of lasers are divided into a plurality of laser emitting groups, and pass through each laser emitting group to all the lasers in a predetermined period of time. The collimating lens 204 projects a laser of the first order of magnitude;

The collimating lens 204 is configured to collimate the multiple incident laser beams and then emit a collimated beam of a first order of magnitude;

The beam splitting device 205 is configured to split an incident collimated beam of a first order of magnitude and then emit a collimated beam of a second order of magnitude;

The second order of magnitude is greater than the first order of magnitude.

In an embodiment of the present disclosure, each of the lasers or each group of the lasers can be individually controlled to emit, so that each group of lasers can be controlled to emit lasers during a preset time period to achieve the target object 3 Projections from different areas. The number of the laser emitting groups is consistent with the number of regions of the target object 3.

In an embodiment of the present disclosure, the laser array 203 may be composed of multiple vertical cavity surface emitting lasers (VCSEL) or multiple edge emitting lasers (Edge Emitting Laser, EEL). After passing through the collimating lens 204, multiple laser beams can become highly parallel collimated beams. According to the requirement of the number of discrete beams in practical applications, the beam splitting device 205 can be used to achieve more collimated beams. The beam splitting device 205 may adopt a diffraction grating (DOE), a spatial light modulator (SLM), and the like.

4 is a schematic diagram of the structure of the optical imaging lens in this disclosure. As shown in FIG. 4, the photodetector array imager 1 includes an optical imaging lens 102, a photodetector array 101, and a driving circuit;

The photodetector array 101 includes a plurality of photodetectors distributed in an array, and the plurality of photodetector emission groups are a plurality of photodetector groups, and each of the photodetector groups and a laser emitting Group corresponding

The photodetector group is configured to receive the collimated light beam reflected by the target object 3 after being emitted by the corresponding laser emitting group;

The optical imaging lens 102 is configured such that the direction vector of the collimated light beam entering the photodetector array 101 through the optical imaging lens 102 has a one-to-one correspondence with the photodetector;

The driving circuit is configured to measure the propagation time of multiple discrete collimated light beams and then generate depth data of multiple regions on the surface of the target object 3, and then according to the depth data of multiple regions of the target object 3 The depth data of the surface of the target object 3 is generated.

In an embodiment of the present disclosure, the photodetector group and the laser emitting group are in a one-to-one correspondence, that is, when the spatial relationship between each detector and the projected collimated beam is accurately corresponded by calibration, in the asynchronous mode Next, only the photodetector group corresponding to the laser group of the collimated beam being projected can be turned on, and the other photodetector groups can be turned off, thereby reducing the power consumption of the photodetector and system noise interference. The number of the photodetector groups is consistent with the number of regions of the target object 3.

In an embodiment of the present disclosure, in order to filter background noise, a narrow-band filter is usually installed in the optical imaging lens 102, so that the photodetector array 101 can only pass the incident collimated light beam with a preset wavelength. The predetermined wavelength may be the wavelength of the incident collimated beam, or may be between 50 nanometers less than the incident collimated beam and 50 nanometers greater than the incident collimated beam. The photodetector array 101 may be arranged periodically or non-periodically. Each photodetector cooperates with the auxiliary circuit to realize the time-of-flight measurement of the straight beam. According to the requirement of the number of discrete collimated beams, the photodetector array 101 can be a combination of multiple single-point photodetectors or a sensor chip integrating multiple photodetectors. In order to further optimize the sensitivity of the photodetector, the irradiation spot of a discrete collimated beam on the target object 3 may correspond to one or more photodetectors. When multiple photodetectors correspond to the same illumination spot, the signal of each detector can be connected through a circuit, so that it can be combined into a photodetector with a larger detection area.

In an embodiment of the present disclosure, the multiple discrete collimated beams are periodically arranged in a predetermined shape, that is, distributed in a geometric regularity.

5(a), (b), (c) are schematic diagrams of the periodic arrangement of multiple discrete collimated beams in the present disclosure. As shown in FIG. 5, in an embodiment of the present disclosure, the preset The shape of includes any of the following shapes or any multiple shapes that can be switched between:

-Straight

-triangle;

-quadrilateral;

-rectangle;

-Round;

-hexagon;

-Pentagon.

Wherein, the shape of the periodic arrangement of the multiple discrete collimated beams is not limited to the above-mentioned shape, and may be arranged in other shapes. As shown in FIG. 5(a), when the preset shape is rectangular, that is, the unit arrangement shape of the collimated beams in one period is rectangular, and it repeats periodically in space. As shown in FIG. 5(b), when the preset shape is a triangle, that is, the unit arrangement shape of the collimated light beam in one period is a triangle, and it repeats periodically in space. As shown in Fig. 5(c), when the preset shape is a hexagon, that is, the unit arrangement shape of the collimated beams in a period is a hexagon, and it repeats periodically in space. Since the implementation of the present disclosure is limited by the optical system, the arrangement of the actual collimated beam in the cross-section may be distorted, such as stretching and distortion. The energy distribution of each collimated beam in the cross-section can be in other shapes such as a circle, a ring, or an ellipse. In such an arrangement as shown in 5, it is beneficial to simplify the spatial correspondence between the multiple discrete collimated beams and the photodetector array 101.

In an embodiment of the present disclosure, the multiple discrete collimated beams are non-periodically arranged in another preset shape.

In an embodiment of the present disclosure, the aperiodic arrangement includes any of the following arrangements or any multiple arrangements that can be switched between:

-Random arrangement;

-Space coding arrangement;

-Quasi-lattice arrangement.

Wherein, the shape of the aperiodic arrangement of the multiple discrete collimated light beams is not limited to the above-mentioned shape, and may be arranged in other shapes. As shown in Figure 6(a), the spatial coding arrangement is specifically that in the periodic arrangement, a part of the light beam is defaulted, so as to realize the spatial coding of the arrangement position. In practice, the coding that can be used is not limited. As shown in Figure 6(a); as shown in Figure 6(b), the random arrangement, specifically the arrangement of collimated beams, is randomly distributed, so that the similarity of the arrangement of different positions is small or close to Zero, as shown in FIG. 6(c), the quasi-lattice arrangement is specifically that the collimated light beams are arranged non-periodically at adjacent positions at a short distance, and periodically arranged at a long distance. Since the implementation of the present disclosure is limited by the optical system, the arrangement of the actual collimated beam in the cross-section may be distorted, such as stretching and distortion. The energy distribution of each collimated beam in the cross-section can be a circle, a ring, or an ellipse. In this arrangement as shown in 6, this arrangement is conducive to uniform sampling of non-determined targets and optimizes the effect of the final 3D depth map.

In an embodiment of the present disclosure, the light detector adopts any of the following light sensors:

-CMOS light sensor;

-CCD light sensor;

-SPAD light sensor.

Wherein, the model selection of the light detector is not limited to the aforementioned light sensor, and may also include other types of light sensors.

In this embodiment, the electronic device provided by the present disclosure includes the 3D imaging device based on asynchronous ToF discrete point cloud, and also includes a display panel; the asynchronous discrete beam projector and the photodetector array imager are located at The backlight side of the display panel;

When the asynchronous discrete beam projector 2 sequentially projects multiple discrete collimated beams to different areas of the target object 3 in a time sequence within a preset period of time, so that the multiple discrete collimated beams penetrate the display panel and then illuminate To the target object 3;

The photodetector array imager 1 receives the multiple discrete collimated light beams reflected by the target object 3 and penetrates the display panel, and obtains the target object 3 according to the propagation time of the multiple discrete collimated light beams The depth data of the multiple regions of the target object 3 is further generated according to the depth data of the multiple regions of the target object 3 to generate the depth data of the surface of the target object 3.

In an embodiment of the present disclosure, the photodetector array imager 1 ensures the spatial position correspondence between the multiple discrete collimated beams projected and the photodetector array 101. In this way, each photodetector in the photodetector array 101 can use the ToF mode of continuously modulating the light beam or pulse in time to measure the propagation time of light, and then calculate the distance of light propagation by means of the speed of light.

The pulse-based ToF method is also called the direct ToF method, specifically: the photodetector can sensitively detect the waveform of a light pulse, and then compare with the emission time of the light pulse to obtain the collimated beam in the asynchronous discrete beam The travel time between the projector 2 and the photodetector array imager 1. In this method, the commonly used photodetector is a single photon avalanche diode (SPAD). The single-photon avalanche diode can count the photons of the light pulse very sensitively and at high speed. That is, the number of photons at different times is counted within the pulse time window, and the overall waveform of the pulse is restored. The pulse-based ToF method has relatively low requirements for the power consumption of the projector, and is beneficial to eliminate the interference of multipath beams.

The ToF method based on time-continuous modulation of the beam is also called the indirect ToF method. Specifically: the time continuous modulation usually adopts a sine wave modulation method, the photodetector can be realized by a CMOS or CCD photosensitive method, and the asynchronous discrete beam projector 2 continuously emits a collimated beam to the target object under high frequency modulation. 3. After being reflected by the target object 3, it is received by the photodetector array 101. Each photodetector records the phase change between the emitted collimated beam and the received collimated beam, so that the depth information of the surface position of the target object 3 can be obtained. Since the ToF method based on time continuous modulation of the beam is an energy integration process, it has higher accuracy than pulsed measurement, and does not require the light source to be a short-time high-intensity pulse. Different types of light sources can be used and different modulation methods can be used.

The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. The above description of the disclosed embodiments enables those skilled in the art to implement or use the present disclosure. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined in this document can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments shown in this text, but should conform to the widest scope consistent with the principles and novel features disclosed in this text.

The specific embodiments of the present disclosure have been described above. It should be understood that the present disclosure is not limited to the foregoing specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which does not affect the essence of the present disclosure.

Claims

A 3D imaging device based on asynchronous ToF discrete point cloud, including asynchronous discrete beam projector and photodetector array imager;

The asynchronous discrete beam projector is configured to sequentially project multiple discrete collimated beams to different regions of the target object in a time sequence within a preset time period;

The photodetector array imager is configured to sequentially receive the multiple discrete collimated beams reflected by the target object and measure the propagation time of the multiple discrete collimated beams, so as to obtain the target The depth data of the multiple regions of the object is generated based on the depth data of the multiple regions of the target object.
The 3D imaging device based on asynchronous ToF discrete point cloud according to claim 1, wherein the asynchronous discrete beam projector comprises an edge emitting laser and a beam projector arranged on an optical path;

The edge emitting laser is configured to project laser light to the beam projector;

The beam projector is configured to project a plurality of discrete collimated beams of the incident laser light sequentially to different regions of the target object in a time sequence within a preset time period.
The 3D imaging device based on asynchronous ToF discrete point cloud according to claim 1, wherein the asynchronous discrete beam projector comprises a laser array, a collimating lens and a beam splitting device arranged on an optical path;

The laser array includes a plurality of lasers arranged in an array, and the plurality of lasers are divided into a plurality of laser emitting groups, and each laser emitting group is sent to the The collimating lens projects the first order of magnitude laser;

The collimating lens is configured to collimate the multiple incident laser beams and then emit a collimated beam of a first order of magnitude;

The beam splitting device is configured to split the incident collimated beam of the first order of magnitude and then emit the collimated beam of the second order of magnitude;

The second order of magnitude is greater than the first order of magnitude.
The 3D imaging device based on asynchronous ToF discrete point cloud according to claim 3, wherein the photodetector array imager comprises an optical imaging lens, a photodetector array, and a driving circuit;

The photodetector array includes a plurality of photodetectors distributed in an array, and the plurality of photodetector emission groups are a plurality of photodetector groups, each of the photodetector groups and a laser emission group Corresponding;

The photodetector group is configured to receive the collimated light beam reflected by the target object after being emitted by the corresponding laser emitting group;

The optical imaging lens is configured such that the direction vector of the collimated light beam entering the photodetector array through the optical imaging lens has a one-to-one correspondence with the photodetector;

The driving circuit is configured to measure the propagation time of multiple discrete collimated light beams and then generate depth data of multiple regions on the surface of the target object, and then generate the depth data based on the depth data of multiple regions of the target object. Describe the depth data of the target surface.
The 3D imaging device based on asynchronous ToF discrete point cloud according to claim 1, wherein the multiple discrete collimated beams are periodically arranged in a predetermined shape.
The 3D imaging device based on asynchronous ToF discrete point clouds according to claim 5, wherein the preset shape includes any of the following shapes or any multiple shapes that can be switched with each other:

-Straight

-triangle;

-quadrilateral;

-rectangle;

-Round;

-hexagon;

-Pentagon.
The 3D imaging device based on asynchronous ToF discrete point clouds according to claim 1, wherein the multiple discrete collimated light beams are non-periodically arranged in another preset shape.
The 3D imaging device based on asynchronous ToF discrete point clouds according to claim 7, wherein the aperiodic arrangement includes any of the following arrangements or any multiple arrangements that can be switched between:

-Random arrangement;

-Space coding arrangement;

-Quasi-lattice arrangement.
The 3D imaging device based on asynchronous ToF discrete point cloud according to claim 1, wherein the asynchronous discrete beam projector includes multiple sets of edge-emitting lasers and beam projectors arranged on an optical path;

The edge-emitting laser is configured to project laser light to the beam projector; the beam projector is configured to project the incident laser light into multiple discrete collimated beams;

By sequentially controlling a group of edge-emitting lasers and beam projectors arranged on an optical path to turn on in the predetermined time period in a time sequence to project multiple discrete collimated beams to different regions of the target object.
An electronic device, comprising the asynchronous ToF discrete point cloud-based 3D imaging device according to any one of claims 1 to 9, further comprising a display panel; the asynchronous discrete beam projector and the photodetector array imaging The device is located on the backlight side of the display panel;

When the asynchronous discrete beam projector projects multiple discrete collimated light beams to different areas of the target object sequentially in time sequence within a preset time period, after the multiple discrete collimated light beams penetrate the display panel Shine on the target object;

The photodetector array imager receives multiple discrete collimated light beams that penetrate the display panel after being reflected by the target object, and obtains multiple discrete collimated light beams according to the propagation time of the multiple discrete collimated light beams. The depth data of the region, and then the depth data of the surface of the target object is generated according to the depth data of multiple regions of the target object.