CN115986556A

CN115986556A - VCSEL array driving device and binocular TOF depth sensing system

Info

Publication number: CN115986556A
Application number: CN202310096839.9A
Authority: CN
Inventors: 王赟; 张官兴
Original assignee: Shanghai Ewa Intelligent Technology Co ltd; Shaoxing Ewa Technology Co ltd
Current assignee: Shanghai Ewa Intelligent Technology Co ltd; Shaoxing Ewa Technology Co ltd
Priority date: 2023-02-02
Filing date: 2023-02-02
Publication date: 2023-04-18

Abstract

The embodiment of the application provides a VCSEL array driving device and a binocular TOF depth perception system. The VCSEL array driving device comprises a VCSEL light source array and a driving circuit; the VCSEL light source array comprises a plurality of groups of light emitting array subsets, each group of light emitting array subsets at least comprises 1 VCSEL light emitting unit, and the VCSEL light emitting units in the light emitting array subsets are arranged at intervals; the driving circuit is electrically connected with the control end of each VCSEL light-emitting unit, and is used for outputting a driving signal to light the VCSEL light-emitting units and outputting a modulation signal to modulate output optical signals of the VCSEL light-emitting units. The provided VCSEL array driving device relates to a novel VCSEL light source array structure and a driving circuit, and provides flexible light source configuration for multiple application scenes. TOF and binocular stereo vision are combined, and a TOF array activation mode and a binocular image sampling mode are configured, so that a high-quality and effective depth image is obtained according to different application scenes and detection distances.

Description

VCSEL array driving device and binocular TOF depth sensing system

Technical Field

The invention relates to the technical field of image processing, in particular to a VCSEL array driving device and a binocular TOF depth sensing system.

Background

Time-Of-Flight (TOF) imaging is a scheme Of acquiring depth information Of a scene by using the Flight Time Of light between a target and a camera, and has the advantages Of small volume, real-Time imaging, high precision and the like. However, in a scattering environment, due to the scattering effect of a scattering medium on light, TOF imaging is affected by multipath interference, depth measurement errors are large, and the application of a TOF camera in a scattering scene is limited.

Meanwhile, when the TOF laser faces a target made of a material with a large absorption rate, depth loss or depth error is increased due to weak reflected light; when a high-density TOF depth image is obtained, an area-array Vertical Cavity Surface-Emitting Laser (VCSEL) needs to be adopted, so that the overall power consumption is high, and the TOF camera is not friendly to independent power supply equipment, so that the existing TOF camera mostly adopts a low-density VCSEL array or a CESEL with only single digit, and the resolution of the obtained depth image is low, and especially in a far target scene, the depth data is too sparse and cannot be used.

Therefore, the existing depth information acquisition scheme has the technical problem that the resolution of a depth map is low due to VCSEL setting.

Disclosure of Invention

In view of the above, embodiments of the present application provide a VCSEL array driving apparatus and a binocular TOF depth sensing system, which at least partially solve the problems in the prior art.

In a first aspect, an embodiment of the present application provides a VCSEL array driving device, where the VCSEL array driving device includes a VCSEL light source array and a driving circuit; wherein the content of the first and second substances,

the VCSEL light source array comprises a plurality of groups of light emitting array subsets, each group of light emitting array subsets at least comprises 1 VCSEL light emitting unit, and the VCSEL light emitting units in the light emitting array subsets are arranged at intervals;

the driving circuit is electrically connected with the control end of each VCSEL light-emitting unit, and is used for outputting a driving signal to light the VCSEL light-emitting units and outputting a modulation signal to modulate the output optical signals of the VCSEL light-emitting units.

According to a specific implementation manner of the embodiment of the application, the light emitting array subsets are arranged at intervals, and a preset space exists between the light emitting units in the light emitting array subsets;

all the light emitting units are arranged in an array.

According to a specific implementation manner of the embodiment of the application, each of the light emitting array subsets is arranged in a ring shape.

According to a specific implementation manner of the embodiment of the application, the subsets of the light emitting arrays are arranged in a staggered manner in rows and columns.

According to a specific implementation manner of the embodiment of the application, the anodes of each group of light emitting array subsets are respectively connected with the power supply anode of the driving circuit.

According to a specific implementation of the embodiments of the present application, the VCSEL light source array is configured as an addressable VCSEL array.

According to a specific implementation manner of the embodiment of the present application, all the VCSEL light emitting units are infrared light emitting units.

In a second aspect, an embodiment of the present invention further provides a binocular TOF depth perception system, including a receiving device, a control device, and the VCSEL array driving device in any one of the first aspects;

the receiving device comprises binocular cameras positioned on the same base line;

the control device is used for controlling the VCSEL array driving device to emit modulated light signals to the surface of a target object, controlling the TOF camera to receive reflected light signals based on the modulated light signals, forming TOF image frames, and calculating depth data according to the TOF image frames, wherein the TOF camera is a left-eye camera and/or a right-eye camera in the binocular camera.

According to a specific implementation manner of the embodiment of the present application, the VCSEL array driving device further includes a lens module, where the lens module includes a collimating lens and a diffractive optical device.

According to a specific implementation manner of the embodiment of the application, the control device comprises a processor and a control circuit, wherein the processor comprises a time sequence generator, a depth engine, a calibration compensation module and a driving module.

According to the VCSEL array driving device and the binocular TOF depth sensing system in the embodiment of the application, the VCSEL array driving device comprises a VCSEL light source array and a driving circuit; the VCSEL light source array comprises a plurality of groups of light emitting array subsets, each group of light emitting array subsets at least comprises 1 VCSEL light emitting unit, and the VCSEL light emitting units in each light emitting array subset are arranged at intervals; the driving circuit is electrically connected with the control end of each VCSEL light-emitting unit, and is used for outputting a driving signal to light the VCSEL light-emitting units and outputting a modulation signal to modulate the output optical signals of the VCSEL light-emitting units. The driving device of the VCSEL array comprises a novel VCSEL light source array structure and a driving circuit, and flexible light source configuration is provided for multiple application scenes.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a VCSEL array driving apparatus according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a binocular TOF depth sensing system according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of another VCSEL array driving apparatus according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a control apparatus of a binocular TOF depth perception system according to an embodiment of the application;

fig. 5 is a schematic structural diagram of an illumination drive of a control device of a binocular TOF depth perception system according to an embodiment of the present application;

fig. 6 is another schematic structural diagram of the illumination driving of the control device of the binocular TOF depth perception system according to the embodiment of the present application;

fig. 7 is another schematic structural diagram of illumination driving of a control device of a binocular TOF depth perception system according to an embodiment of the present application.

Detailed Description

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

The following description of the embodiments of the present application is provided by way of specific examples, and other advantages and effects of the present application will be readily apparent to those skilled in the art from the disclosure herein. It should be apparent that the described embodiments are only a few embodiments of the present application, and not all embodiments. The present application is capable of other and different embodiments and its several details are capable of modifications and/or changes in various respects, all without departing from the spirit of the present application. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

It is noted that various aspects of the embodiments are described below within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present application, one skilled in the art should appreciate that one aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number of the aspects set forth herein. Additionally, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present application, and the drawings only show the components related to the present application rather than the number, shape and size of the components in actual implementation, and the type, amount and ratio of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects may be practiced without these specific details.

Referring to fig. 1, a schematic structural diagram of a VCSEL array driving apparatus according to an embodiment of the present disclosure is shown. As shown in fig. 1, the VCSEL array driver 100 includes a VCSEL light source array 110 and a driving circuit 120; wherein the content of the first and second substances,

the VCSEL light source array 110 includes a plurality of light emitting array subsets 111, each light emitting array subset includes at least 1 VCSEL light emitting unit 112, and the VCSEL light emitting units 112 in each light emitting array subset 111 are arranged at intervals;

the driving circuit 120 is electrically connected to the control end of each VCSEL light-emitting unit 112, and the driving circuit 120 is configured to output a driving signal to light the VCSEL light-emitting unit 112 and output a modulation signal to modulate an output optical signal of the VCSEL light-emitting unit 112.

The VCSEL array driving apparatus 100 provided in this embodiment is applied to a binocular TOF depth sensing system, and is used for emitting laser signals and detecting depth information of a surface of a target object. As shown in fig. 2, the binocular TOF depth perception system 200 includes a VCSEL array driving device 100, a receiving device 210, and a control device 220, the control device 220 is a main control device, the VCSEL array driving device 100 is a component for emitting a modulated light signal, and the receiving device 210 is a component for receiving a reflected light signal, and is composed of a binocular camera.

As shown in fig. 1, the VCSEL array driver 100 includes a VCSEL light source array 110 and a driving circuit 120, which drives the VCSEL light source array to emit light and controls light emission parameters. Specifically, the VCSEL light source arrays are divided into a plurality of groups, each group of VCSELs forms a light emitting array subset, and each group of light emitting array subsets at least comprises 1 VCSEL unit; and the VCSEL units of each light emitting array subset are arranged at intervals. The VCSEL array is configured to individually control the VCSEL units in each group or subset of light emitting arrays in accordance with a driving signal. Besides being lighted according to the driving signal, the VCSEL array also modulates the frequency and amplitude of the output optical signal according to the modulation signal of the driving circuit, and the modulation may include one or more combinations of sine wave modulation, linear frequency modulation, multi-frequency modulation and pulse wave modulation.

The VCSEL light emitting units may be all infrared light emitting units, and the infrared light source provided by the VCSEL array driving device may be at least one of an infrared floodlight source, an infrared structure light source, and an infrared speckle light source.

all the light emitting units are arranged in an array.

In this embodiment, the light emitting array subsets are arranged at intervals in consideration of different lighting timings of the subsets. After the light emitting array subsets arranged at intervals pass through the beam expanding lens, each subset can uniformly project modulated light signals to a target when being lightened at a corresponding time sequence, and the modulated light signals with uniformity and different sparsity can be projected by configuring different control signals. Each minimum light-emitting unit can comprise an infrared laser lamp bead, the light-emitting units connected in each string are a group of light-emitting units with the same color, and the colors are not displayed based on drawing requirements of the attached drawings of the application documents. In specific implementation, as shown in fig. 1, the 1 st to 5 th to 9 th lines of the TX1 connection are the same color, the 2 nd to 6 th to 10 th lines of the TX2 connection are the same color, the 3 rd to 7 th to 11 th lines of the TX3 connection are the same color, and the 4 th to 8 th to 12 th lines of the TX4 connection are the same color. Of course, the specific connection may be specifically adjusted according to the lighting scheme, and is not limited.

On the basis, in order to prevent heat concentration of the vcsel carrier, for example, the carrier is lightened according to the sequence of 1/3-2/4, the middle of 1/3 of lines is empty when the carrier is lightened.

According to another specific implementation manner of the embodiment of the present application, as shown in fig. 1, the subsets of the light emitting arrays are arranged in a staggered manner.

According to a specific implementation manner of the embodiment of the present application, as shown in fig. 2, each of the subsets of light emitting arrays is arranged in a ring shape.

In specific implementation, the corresponding arrangement scheme may be specifically selected according to the display scheme, for example, the row-column misalignment arrangement scheme shown in fig. 1, or the circular ring arrangement scheme shown in fig. 2. The light emitting units of the VCSEL array driving device are arranged at intervals, and uniform distribution of light sources is achieved while the VCSEL units in each group of light emitting array subsets or each light emitting array subset are independently controlled.

The entire VCSEL array is configured as a common driving power supply cathode, and the anodes of each group of light emitting array subsets are respectively connected with the driving power supply corresponding channel anodes, so as to drive each light emitting array subset individually.

Further, each of the subsets of light emitting arrays may be configured to be sequentially driven to light in a predetermined sequence, for example, the predetermined sequence is 1-2-3-4, 1-3-2-4, or 1/2-3/4, 1/3-2/4, etc., to realize different lighting patterns. The LED light source is lightened according to a preset sequence in a time-sharing mode, power consumption is convenient to control, modulated light with different sparse density combinations can be projected, the optical power density during each lightening process is improved, and the power load is reduced.

In this embodiment, the VCSEL array is configured as an addressable VCSEL array, i.e., individual VCSEL units or subsets of the light emitting array can be individually driven according to addressing command information.

An addressable laser array refers to a light emitting point of an activated area in the array which can be adjusted according to an applicable scene under the condition of a certain total emitting power. For example, in a close-range face recognition scene, considering safety and distance, part of VCSEL units in the lighting array can be uniformly activated; for target measurements at a slightly greater distance, energy concentration is required, so that the VCSEL units in the central region can be illuminated in a concentrated manner, thereby concentrating the energy in the central region. Therefore, the use safety and the effectiveness of the VCSEL array driving device can be effectively improved.

In the VCSEL array driving device provided in the embodiment of the present application, the VCSEL array driving device includes a VCSEL light source array and a driving circuit; the VCSEL light source array comprises a plurality of groups of light emitting array subsets, each group of light emitting array subsets at least comprises 1 VCSEL light emitting unit, and the VCSEL light emitting units in the light emitting array subsets are arranged at intervals; the driving circuit is electrically connected with the control end of each VCSEL light-emitting unit, and is used for outputting a driving signal to light the VCSEL light-emitting units and outputting a modulation signal to modulate the output optical signals of the VCSEL light-emitting units. The provided VCSEL array driving device designs a novel VCSEL light source array structure and a driving circuit, and provides flexible light source configuration for multiple application scenes.

Referring to fig. 2, a schematic structural diagram of a binocular TOF depth perception system provided in an embodiment of the present invention is shown. As shown in fig. 2, the binocular TOF depth perception system 200 includes a receiving device 210, a control device 220 and a VCSEL array driving device, which may be the VCSEL array driving device 100 provided in the above embodiment.

The receiving device 210 comprises a binocular camera located on the same baseline;

the control device 220 is configured to control the VCSEL array driving device 100 to emit a modulated light signal to a surface of a target object, control a TOF camera to receive a reflected light signal based on the modulated light signal, form a TOF image frame, and calculate depth data according to the TOF image frame, where the TOF camera is a left-eye camera and/or a right-eye camera of the binocular camera.

The control device 220 serves as a main control device, the VCSEL array driving device 100 is a component for emitting a modulated optical signal, and the receiving device 210 is a component for receiving a reflected optical signal and is formed by a binocular camera.

The receiving device 210 includes binocular cameras, i.e., a left eye camera and a right eye camera on the same baseline, each camera includes an image sensor, a filter and an optical lens, and is configured to modulate a driving signal according to the phase shift method of the laser light source projector, and synchronously receive phase shift images reflected by the floodlight projector and the laser speckle projector after illuminating the object surface, and a CCD, a CMOS, an avalanche diode SPAD array, and the like are used for general image sensing. Optionally, the left eye camera and the right eye camera are both infrared cameras.

The VCSEL array driver 100 and at least one monocular camera of the binocular cameras in the receiver 210 form a TOF camera system, for example, a TOF camera system with the left eye camera or the right eye camera, and the binocular camera forms a binocular system, preferably with the left eye camera as a reference camera, although the binocular TOF camera system may also be formed with the left eye camera and the right eye camera. Acquiring binocular TOF image frames when both the left and right cameras are configured to receive the modulated light signals; and the binocular image frame and the binocular TOF image frame can be subjected to binocular stereo matching calculation.

According to a specific implementation manner of the embodiment of the present application, the VCSEL array driver 100 may further include a lens module including a collimating lens and a diffractive optical device.

The lens module comprises a collimating lens and a Diffractive Optical Element (DOE), modulated optical signal laser emitted by a laser source is collimated by the collimating lens and then is emitted in a concentrated manner to a specific direction, and then is expanded by the DOE, for example, the original light is expanded by a 2X 2 VCSEL array, and 4 collimated laser beams are generated after passing through the collimating lens, although the four laser beams have a certain divergence angle, the whole target scene cannot be uniformly illuminated by a large view field, and therefore the beam is expanded by the DOE. The DOE in the TOF is used for expanding and homogenizing the output modulated light signals, so that the narrow light beams are expanded to a wider angle range and have a uniform illumination field.

Specifically, the vcsel array expands the beam to four times, generally an odd number of times, of the original beam after passing through the beam expander, and the original spot pattern is located at the center. Or the VCSEL array can be composed of arrays with different density, such as dense arrays and sparse arrays, so as to adopt different projection modes for different application scenes and purposes;

according to a specific implementation manner of the embodiment of the application, the control device comprises a processor and a control circuit, wherein the processor comprises a time sequence generator, a depth engine, a calibration compensation module and ^{drive module} _。

As shown in fig. 4, the control device 220 includes a processor 221 and peripheral control circuits, such as a power supply unit, a memory unit, etc., coupled to drive one or more infrared light sources to output modulated light signals and control the image sensor in the receiving device 210 to acquire modulated light reflection signals according to a preset pattern, and the control device 220 is further configured to process the measured target depth data from the binocular view and/or the TOF phase map. The processor 221 includes a timing generator 222, a depth engine 223, a calibration compensation module 224, and an illumination driver 225, the functions of each of which will be explained separately below.

The timing generator 222 is configured to provide synchronous clock signals for the infrared light source and the image sensor, so as to implement synchronous control of modulating light signals and image acquisition, frame rate control, and the like. The depth engine 223 is used to calculate modulated light reflectance signal phase map depth data from the image sensor data, and further the depth engine is configured to calculate binocular image disparity data. The calibration compensation module 224: the method is used for compensating and calibrating the phase, the amplitude, the image and the like according to factors such as an image sensor, temperature, circuit crosstalk, lens distortion and the like. As shown in fig. 5, illumination driver 225 outputs a modulated drive voltage or current based on the clock signal and the emission power control signal to drive the infrared light source to emit a periodically modulated light signal to activate one or more individually addressable subsets of the light emitting arrays of the plurality of VCSEL units.

Further, the illumination driver 225 includes a plurality of independent illumination driver output circuit channels TX _ n, each coupled to a corresponding subset of the light emitting arrays, configured to activate at least one corresponding illumination driver output channel at a given point in time and to activate to illuminate the corresponding subset of the light emitting arrays in accordance with a control command.

Further, the illumination driver 225 may be further configured such that in the multi-channel mode, the illumination driver sequentially activates different illumination driver output channels at different time points and sequentially activates to illuminate corresponding subsets of the light emitting arrays, and the activation illumination sequence is programmable.

In addition, as shown in fig. 6 and 7, the illumination driver 225 may further include an N-channel vertical addressing illumination driver V _ TX _ N and an M-channel horizontal addressing illumination driver H _ TX _ M, respectively, coupled to the rows and columns of the light emitting array, and configured to drive the light emitting array by driving the corresponding vertical/horizontal illumination driver output circuit according to the vertical and horizontal addressing commands, thereby enabling independent control of the individual rows or columns of the light emitting array or a subset of the light emitting array.

Further, as shown in FIG. 6, the light emitting array is arranged with the anode common to the rows and the cathode common to the columns of the light emitting array, or vice versa.

In another embodiment, as shown in FIG. 7, the rows or columns of the light emitting array are in a non-common configuration. If each row of the light emitting array is configured with a common cathode, each light emitting unit in each row of the light emitting array is separately coupled and connected with the corresponding input driving circuit channel.

According to the binocular TOF depth perception system provided by the embodiment of the application, the VCSEL array driving device comprises a VCSEL light source array and a driving circuit; the VCSEL light source array comprises a plurality of groups of light emitting array subsets, each group of light emitting array subsets at least comprises 1 VCSEL light emitting unit, and the VCSEL light emitting units in the light emitting array subsets are arranged at intervals; the driving circuit is electrically connected with the control end of each VCSEL light-emitting unit, and is used for outputting a driving signal to light the VCSEL light-emitting units and outputting a modulation signal to modulate the output optical signals of the VCSEL light-emitting units. The VCSEL array driving device designs a novel VCSEL light source array structure and a driving circuit, provides flexible light source configuration for multiple application scenes, and effectively acquires binocular depth information. The TOF is combined with binocular stereo vision, so that the resolution of a depth image can be improved, the complexity of binocular stereo matching and depth calculation is simplified, and the image information and the depth information of each pixel point can be acquired simultaneously. Furthermore, a TOF array activation mode and a binocular image sampling mode can be configured, so that high-quality and effective depth images can be obtained according to different application scenes and different detection distances.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The VCSEL array driving device is characterized by comprising a VCSEL light source array and a driving circuit; wherein, the first and the second end of the pipe are connected with each other,

2. The VCSEL array driver of claim 1, wherein each of the subsets of light emitting arrays is spaced apart, and a predetermined space exists between each of the light emitting units in each of the subsets of light emitting arrays;

all the light emitting units are arranged in an array.

3. The VCSEL array driver of claim 2, wherein each of the subsets of light emitting arrays is arranged in a circular ring.

4. The VCSEL array driving device of claim 2, wherein each of the subsets of light emitting arrays is staggered in rows and columns.

5. The VCSEL array driving device of any of claims 1 to 4, wherein anodes of each of the subsets of light emitting arrays are respectively connected to a power supply anode of a driving circuit.

6. The VCSEL array driving device of claim 1, wherein the VCSEL light source array is configured as an addressable VCSEL array.

7. The VCSEL array driver of claim 1, wherein the VCSEL light emitting units are all infrared light emitting units.

8. A binocular TOF depth perception system comprising receiving means, control means and the VCSEL array driving means of any of claims 1 to 7;

9. The binocular TOF depth perception system of claim 8, wherein the VCSEL array driver further includes a lens module including a collimating lens and diffractive optics.

10. The binocular TOF depth perception system of claim 8, wherein the control device includes a processor and a control circuit, the processor including a timing generator, a depth engine, a calibration compensation module, and a drive module.