CN115102036B

CN115102036B - Lattice laser emission structure, lattice laser system and depth calculation method

Info

Publication number: CN115102036B
Application number: CN202211015861.8A
Authority: CN
Inventors: 郑治钦; 张军; 智强; 谢锦阳; 闫合; 张健; 唐昊
Original assignee: Lizhen Precision Intelligent Manufacturing Kunshan Co ltd
Current assignee: Lizhen Precision Intelligent Manufacturing Kunshan Co ltd
Priority date: 2022-08-24
Filing date: 2022-08-24
Publication date: 2022-11-22
Anticipated expiration: 2042-08-24
Also published as: CN115102036A

Abstract

The invention discloses a dot matrix laser emission structure, a dot matrix laser system and a depth calculation method. The lattice laser emission structure comprises a first lattice laser emitter, a second lattice laser emitter and a diffraction optical element, wherein the first lattice laser emitter emits a first laser beam with a first wavelength, the second lattice laser emitter emits a second laser beam with a second wavelength, and the second wavelength is different from the first wavelength. The first laser beam and the second laser beam respectively form a first structured light pattern and a second structured light pattern through the diffractive optical element, the projection area of the first structured light pattern is at least partially overlapped with the projection area of the second structured light pattern, and the second laser spots in the second structured light pattern are arranged in a staggered mode with the first laser spots of the first structured light pattern. The second laser spot with the wavelength different from that of the first laser spot is used as a characteristic point to realize area identification, and a denser laser transmitter can be arranged, so that the identification precision is improved.

Description

Lattice laser emission structure, lattice laser system and depth calculation method

Technical Field

The invention relates to the technical field of optics, in particular to a dot matrix laser emission structure, a dot matrix laser system and a depth calculation method.

Background

Fig. 1 is a schematic structural diagram of a lattice laser emission structure in the prior art, fig. 2 is a schematic structural diagram of another lattice laser emission structure in the prior art, and fig. 3 is a schematic structural diagram of a lattice laser emitter in the prior art, as shown in fig. 1 to fig. 3, the lattice laser emitter in the prior art includes a laser lattice composed of semiconductor lasers 10' having a certain arrangement rule, exemplarily, as shown in fig. 3, a group of laser lattices are arranged in a square shape, a group of laser lattices are arranged in a circular shape, a group of laser lattices are arranged in a triangular shape, a group of laser lattices are arranged in a hexagonal shape, and regions in which the groups of laser lattices are distributed are overlapped. After a laser beam emitted by the dot matrix laser emitter is projected to a target object, the target object is shot by the camera, laser points in a shot picture are identified, circular dot matrix laser, triangular dot matrix laser, hexagonal dot matrix laser, square dot matrix laser and the like are identified, then each laser point in the picture is in one-to-one correspondence with the semiconductor laser 10 'in the dot matrix laser emitter, the semiconductor laser 10' which emits the laser point in the picture is identified, the depth information of each laser point is finally calculated, then a three-dimensional reconstruction graph can be carried out according to the depth information of each laser point, and functions of target object identification and the like are realized.

In the above technical solution, the laser spot recognition of the picture shot by the camera is mainly based on the arrangement and distribution of different semiconductor lasers 10 'in the lattice laser transmitter, so that the semiconductor lasers 10' cannot be densely arranged, and the accuracy of target object recognition is not high.

Disclosure of Invention

The invention provides a dot matrix laser emission structure, a dot matrix laser system and a depth calculation method, which are used for improving the identification accuracy.

According to an aspect of the present invention, there is provided a lattice laser emitting structure, including:

the laser device comprises a first dot matrix laser transmitter, a second dot matrix laser transmitter and a laser processing unit, wherein the first dot matrix laser transmitter comprises a plurality of first laser transmitters arranged in an array, and the first laser transmitters are used for transmitting a first laser beam with a first wavelength;

the second lattice laser emitter comprises a plurality of second laser emitters which are arranged in an array, the second laser emitters are used for emitting second laser beams with second wavelengths, and the second wavelengths are different from the first wavelengths;

a diffractive optical element including a first diffraction grating and a second diffraction grating;

the first diffraction grating is positioned on a propagation path of the first laser beam, and the first laser beam passes through the first diffraction grating to form a first structured light pattern;

the second diffraction grating is positioned on a propagation path of the second laser beam, and the second laser beam passes through the second diffraction grating to form a second structured light pattern;

the projection area of the first structured light pattern is a first projection area, the projection area of the second structured light pattern is a second projection area, the first projection area and the second projection area are at least partially overlapped, and second laser spots in the second structured light pattern and first laser spots of the first structured light pattern are arranged in a staggered mode.

Optionally, the number of the first laser emitters is greater than the number of the second laser emitters.

Optionally, the second wavelength is λ 1, where λ 1 is greater than or equal to 400nm and less than or equal to 1100nm.

Optionally, the second wavelength is greater than the first wavelength;

the grating period of the second diffraction grating is greater than the grating period of the first diffraction grating.

Optionally, the grating period of the first diffraction grating is d1, and the grating period of the second diffraction grating is d2, where d1 is less than or equal to 2 μm, and d2 is less than or equal to 2 μm.

Optionally, the first laser beam and the second laser beam comprise first polarized light;

the lattice laser emission structure also comprises a polaroid;

the polarizing plate is located on a propagation path of the first laser beam and the second laser beam, and a polarization direction of the polarizing plate is the same as a polarization direction of the first polarized light.

According to another aspect of the present invention, there is provided a lattice laser system comprising:

any of the dot array laser emitting structures described in the first aspect, configured to project a first structured-light pattern and a second structured-light pattern towards a target field of view;

a camera for acquiring a depth image of the target field of view, the depth image including images of the first and second structured light patterns formed on a target object;

and the processor is respectively connected with the dot matrix laser emission structure and the camera and is used for controlling the dot matrix laser emission structure to project a first structural light pattern and a second structural light pattern to a target view field, acquiring a depth image of the target view field through the camera and calculating the depth information of the target object based on the depth image.

According to another aspect of the present invention, there is provided a depth calculation method for the lattice laser system of the second aspect, the depth calculation method comprising:

controlling the lattice laser emission structure to project a first structured light pattern and a second structured light pattern to the target field of view;

acquiring a depth image of the target field of view by a camera, wherein the depth image comprises images of the first structured light pattern and the second structured light pattern formed on a target object;

determining an image position of the second structured-light pattern in the depth image formed on the target object;

determining the image position of the first structured light pattern on the target object in the depth image according to the image position of the second structured light pattern on the target object;

calculating depth information of the target object according to the image position formed by the first structured light pattern on the target object.

Optionally, before controlling the dot matrix laser emission structure to project the first structured light pattern and the second structured light pattern to the target field of view, the method further includes:

controlling the lattice laser emission structure to project a first structured light pattern and a second structured light pattern to a reference object;

acquiring a reference depth image of the reference object through the camera, wherein the reference depth image comprises images of the first structured light pattern and the second structured light pattern formed on the reference object;

calculating depth information of the target object from the image position of the first structured light pattern formed on the target object, including:

based on the reference depth image, calculating depth information of the target object from the image position of the first structured light pattern formed on the target object.

Optionally, acquiring the reference depth image of the target object through the camera includes:

acquiring a periodic depth image of the target object through the camera, wherein the periodic depth image is a partial image of the first structured light pattern and the second structured light pattern which are periodically distributed in an image formed on the reference object;

and acquiring the reference depth image according to the periodic depth image, wherein the size of the reference depth image is larger than that of the periodic depth image.

According to the dot matrix laser emitting structure, the dot matrix laser system and the depth calculating method provided by the embodiment of the invention, the first dot matrix laser emitter and the second dot matrix laser emitter which are different in wavelength and the diffractive optical element with the first diffraction grating and the second diffraction grating are arranged, so that a first laser beam emitted by the first dot matrix laser emitter forms a first structural light pattern through the first diffraction grating, a second laser beam emitted by the second dot matrix laser emitter forms a second structural light pattern through the second diffraction grating, a projection area of the first structural light pattern is at least partially overlapped with a projection area of the second structural light pattern, and second laser spots in the second structural light pattern are arranged in a staggered mode with first laser spots of the first structural light pattern, so that the second laser spots in the second structural light pattern are used as characteristic points to realize area identification.

It should be understood that the statements in this section do not necessarily identify key or critical features of the embodiments of the present invention, nor do they necessarily limit the scope of the invention. Other features of the present invention will become apparent from the following description.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a lattice laser emitting structure in the prior art;

FIG. 2 is a schematic diagram of another prior art lattice laser emitting structure;

FIG. 3 is a schematic diagram of a prior art lattice laser transmitter;

fig. 4 is a schematic structural diagram of a lattice laser emission structure according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of another lattice laser emitting structure provided in an embodiment of the present invention;

fig. 6 is a schematic front view of a lattice laser emitting structure according to an embodiment of the present invention;

fig. 7 is a schematic top view of a lattice laser emitting structure according to an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a first structured light pattern and a second structured light pattern according to an embodiment of the present invention;

FIG. 9 is an enlarged schematic view of FIG. 8 at A;

fig. 10 is a schematic diagram of laser spot distributions of a first dot matrix laser transmitter and a second dot matrix laser transmitter according to an embodiment of the present invention;

FIG. 11 is a schematic diagram illustrating a partial structure of a diffractive optical element according to an embodiment of the present invention;

fig. 12 is a schematic structural diagram of another lattice laser emitting structure provided in an embodiment of the present invention;

FIG. 13 is a schematic structural diagram of another lattice laser emitting structure according to an embodiment of the present invention;

fig. 14 is a schematic front view of another lattice laser emitting structure provided in an embodiment of the present invention;

fig. 15 is a schematic top view of another lattice laser emitting structure provided in an embodiment of the present invention;

fig. 16 is a schematic structural diagram of a lattice laser system according to an embodiment of the present invention;

fig. 17 is a schematic flowchart of a depth calculation method according to an embodiment of the present invention;

FIG. 18 is a schematic structural diagram of another first structured light pattern and a second structured light pattern according to an embodiment of the present invention;

FIG. 19 is a schematic diagram of another exemplary embodiment of a lattice laser system;

FIG. 20 is a schematic flowchart of another depth calculation method according to an embodiment of the present invention;

fig. 21 is a schematic structural diagram of a depth calculation method according to an embodiment of the present invention;

FIG. 22 is a schematic structural diagram of a first structured light pattern and a second structured light pattern according to an embodiment of the present invention;

FIG. 23 is a schematic structural diagram of another lattice laser system according to an embodiment of the present invention;

fig. 24 is a schematic flowchart of another depth calculation method according to an embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Moreover, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Fig. 4 is a schematic structural diagram of a dot matrix laser emission structure according to an embodiment of the present invention, fig. 5 is a schematic structural diagram of another dot matrix laser emission structure according to an embodiment of the present invention, fig. 6 is a schematic structural diagram of a front view of a dot matrix laser emission structure according to an embodiment of the present invention, fig. 7 is a schematic structural diagram of a top view of a dot matrix laser emission structure according to an embodiment of the present invention, fig. 8 is a schematic structural diagram of a first structured light pattern and a second structured light pattern according to an embodiment of the present invention, and fig. 9 is an enlarged structural diagram of fig. 8 at a.

The dot matrix laser emitting structure provided by this embodiment is applicable to a dot matrix laser system of a front camera of a mobile phone to realize functions such as face recognition, but is not limited thereto.

As shown in fig. 4 to 9, the dot matrix laser emitting structure provided by the embodiment of the present invention includes:

the laser device comprises a first dot matrix laser emitter 20, wherein the first dot matrix laser emitter 20 comprises a plurality of first laser emitters 21 arranged in an array, and the first laser emitters 21 are used for emitting first laser beams with first wavelengths.

And the second dot matrix laser emitter 22, the second dot matrix laser emitter 22 includes a plurality of second laser emitters 23 arranged in an array, the second laser emitters 23 are configured to emit a second laser beam having a second wavelength, and the second wavelength is different from the first wavelength.

The diffractive optical element 24 includes a first diffraction grating 241 and a second diffraction grating 242.

The first diffraction grating 241 is located on a propagation path of the first laser beam, which passes through the first diffraction grating 241 to form the first structured light pattern 30.

The second diffraction grating 242 is located on the propagation path of the second laser beam, and the second laser beam passes through the second diffraction grating 242 to form the second structured light pattern 31.

The projection area of the first structured light pattern 30 is a first projection area 32, the projection area of the second structured light pattern 31 is a second projection area 33, the first projection area 32 and the second projection area 33 at least partially overlap, and the second laser spots 311 in the second structured light pattern 31 are staggered with the first laser spots 301 in the first structured light pattern 30.

Specifically, as shown in fig. 4-7, the first dot matrix laser emitter 20 and the second dot matrix laser emitter 22 are distributed on the circuit board 25, and the second dot matrix laser emitter 22 may be disposed on one side of the first dot matrix laser emitter 20. Driving circuits (not shown) are distributed around the first dot matrix laser emitter 20 and the second dot matrix laser emitter 22 to drive the first dot matrix laser emitter 20 and the second dot matrix laser emitter 22 to reflect the first laser beam and the second laser beam.

Wherein the first and second laser beams may be visible light. In some embodiments, the first laser beam and the second laser beam may also be non-visible light, such as infrared light or near-infrared light, for example. Since the user cannot see the invisible light, the invisible light can be subjected to non-sensing detection.

With continued reference to fig. 4-7, optionally, a connection line 26 is disposed on the circuit board 25, and when the lattice laser emitting structure is used in a lattice laser system of a front camera of a mobile phone, the first lattice laser emitter 20 and the second lattice laser emitter 22 may be connected to a main board of the mobile phone through the connection line 26, so that the main board supplies power to the first lattice laser emitter 20 and the second lattice laser emitter 22. Meanwhile, the first dot matrix laser emitter 20 and the second dot matrix laser emitter 22 can also be connected with a processor on the motherboard through a connection line 26, so that the processor can drive and control the first dot matrix laser emitter 20 and the second dot matrix laser emitter 22.

Fig. 10 is a schematic diagram of laser spot distribution of a first dot matrix laser emitter and a second dot matrix laser emitter according to an embodiment of the present invention, and exemplarily, when the diffractive optical element 24 is not provided, laser spots of the dot matrix laser emitting structure irradiated onto the test panel are as shown in fig. 10, a first laser beam having a first wavelength is emitted by a first laser emitter 21 of the first dot matrix laser emitter 20, the first laser beam forms a first dot matrix spot 41 on the test panel, a second laser beam having a second wavelength is emitted by a second laser emitter 23 of the second dot matrix laser emitter 22, and the second laser beam forms a second dot matrix spot 42 on the test panel, wherein the first dot matrix spot 41 and the second dot matrix spot 42 are both formed by laser spots arranged in an array, and a projection area 43 of the first dot matrix spot 41 and a projection area 44 of the second dot matrix spot 42 are not overlapped.

Fig. 11 is a schematic partial structure diagram of a diffractive optical element according to an embodiment of the present invention, and as shown in fig. 4-7 and fig. 11, the diffractive optical element 24 works based on fraunhofer multi-slit diffraction effect, and is configured to diffract lattice light into more lattices to be emitted. As shown in fig. 11, the diffractive optical element 24 may include a substrate 45 and a plurality of slits 46 etched on the substrate 45, each slit 46 satisfying a diffraction effect, so that the plurality of slits 46 form a diffraction grating, an optical field on a diffraction plane is formed by coherent superposition of light emitted from each slit 46, and when a difference between optical paths of light emitted from two adjacent slits 46 reaching an interference point is an integral multiple of a wavelength of the light, phases of the two light beams are the same, and an interference strengthening phenomenon occurs. In the present embodiment, by controlling the shape and width of the slit 46 and the grating period of the diffraction grating, lattice light of different diffraction orders can be modulated.

With continued reference to fig. 4-9, in the present embodiment, the diffractive optical element 24 includes a first diffraction grating 241 and a second diffraction grating 242, and the first diffraction grating 241 may cover the first dot matrix laser emitter 20 along the thickness direction of the circuit board 25, such that the first diffraction grating 241 is located on the propagation path of the first laser beam, and the first laser beam is diffracted into the first structured light pattern 30 through the first diffraction grating 241. The second diffraction grating 242 covers the second lattice laser emitter 22 such that the second diffraction grating 242 is located on a propagation path of the second laser beam, which is diffracted into the second structured-light pattern 31 by the second diffraction grating 242.

As shown in fig. 8 to 10, when the material of the diffractive optical element 24 and the angle of the incident light are fixed, by setting the widths of the slits of the first diffraction grating 241 and the second diffraction grating 242 and the grating period of the diffraction gratings, the diffraction lattice structured light having positive and negative orders in the horizontal direction and the vertical direction can be obtained, and the first laser beam and the second laser beam can be expanded into the structured light of 9 times. As shown in fig. 8 to 10, in this case, the diffractive optical element 2 expands the second lattice spot 42 of the original first lattice spot 41 into 9 equal parts of 3 × 3 lattice spots, so as to form the first structured light pattern 30 and the second structured light pattern 31 of a 3 × 3 structure.

With continued reference to fig. 8-10, the projected areas of the first and second

structured light patterns

30 and 31 do not coincide in the same diffraction order, but by setting the widths of the slits of the first and

second diffraction gratings

241 and 242 and the grating periods of the diffraction gratings, the projected areas of the adjacent first and second

structured light patterns

30 and 31 may overlap in different diffraction orders.

Illustratively, as shown in fig. 8 and 9, the diffraction orders of the first and second

structured light patterns

30 and 31 in the middle column are zero orders, the diffraction orders of the first and second

structured light patterns

30 and 31 on the left side of the zero order are negative orders, and the diffraction orders of the first and second

structured light patterns

30 and 31 on the right side of the zero order are positive orders. Wherein the projected area of the first structured light pattern 30 of the zeroth order and the projected area of the second structured light pattern 31 do not overlap, the projected area of the first structured light pattern 30 of the negative first order and the projected area of the second structured light pattern 31 do not overlap, and the projected area of the first structured light pattern 30 of the positive first order and the projected area of the second structured light pattern 31 do not overlap. The projected area of the first structured light pattern 30 of zero order overlaps the projected area of the second structured light pattern 31 of negative first order, and the projected area of the first structured light pattern 30 of positive first order overlaps the projected area of the second structured light pattern 31 of zero order, so that the projected areas of the first structured light patterns 30 of different diffraction orders constitute one complete projected area.

It should be noted that, in the above-described embodiment, only the diffraction orders in the horizontal direction and the vertical direction include the zero order and the plus and minus one order (the laser spot expansion is 9 times), but the present invention is not limited to this, and in other embodiments, the diffraction orders in the horizontal direction and the vertical direction may include the plus and minus two orders (the laser spot expansion is 25 times), and the like, and the embodiment of the present invention is not limited to this.

With continued reference to fig. 9, in the overlapping region of the projection region of the first structured light pattern 30 and the projection region of the second structured light pattern 31, the first laser spots 301 in the first structured light pattern 30 and the second laser spots 311 in the second structured light pattern 31 are arranged alternately, i.e. the first laser spots 301 in the first structured light pattern 30 and the second laser spots 311 in the second structured light pattern 31 do not overlap, or in the overlapping region of the projection region of the first structured light pattern 30 and the projection region of the second structured light pattern 31, the second laser spots 311 in the second structured light pattern 31 are arranged in the gap between adjacent first laser spots 301 in the first structured light pattern 30, so that the second laser spots 311 in the second structured light pattern 31 can be clearly identified from the first laser spots 301 in the first structured light pattern 30.

In practical applications, the lattice laser emission structure projects the first structured light pattern 30 and the second structured light pattern 31 to a target field of view, and a camera captures images of the first structured light pattern 30 and the second structured light pattern 31 formed on a target object in the target field of view, so as to obtain a depth image. When the depth image is processed, the second laser spot 311 in the second structured light pattern 31 is firstly identified, the diffraction spots of the zero order and the plus-minus one order are positioned according to the distribution area position of the second laser spot 311 in the second structured light pattern 31 in the depth image, the distribution area position of the first laser spot 301 in the first structured light pattern 30 in the depth image is further identified, after the position of the first laser spot 301 in the first structured light pattern 30 in the depth image is identified, the first laser spot 301 in the first structured light pattern 30 is in one-to-one correspondence with the first laser emitter 21 in the first dot matrix laser emitter 20, and the first laser spot 301 in the first structured light pattern 30 in the depth image is identified, so that the depth information of each first laser spot 301 in the first structured light pattern 30 can be calculated, and the three-dimensional reconstruction map of the target object can be restored through the depth information of each first laser spot 301 in the first structured light pattern 30.

It can be understood that, when the dot matrix laser emission structure is applied to an application scene of face recognition, a three-dimensional reconstruction image of the whole face can be restored, and further a face recognition function can be realized, but the dot matrix laser emission structure is not limited to the application scene.

Before the technical solutions disclosed in the embodiments of the present disclosure are used, the user should be informed of the type, the use range, the use scene, and the like of the personal information related to the present disclosure in a proper manner according to relevant laws and regulations and obtain the authorization of the user.

With continued reference to fig. 4-7, optionally, the first diffraction grating 241 and the second diffraction grating 242 may be disposed on the same substrate, that is, two kinds of slits 46 suitable for different wavelengths are engraved on the same substrate, and different diffraction fringes are formed as the first diffraction grating 241 and the second diffraction grating 242, so as to reduce the number of devices and facilitate the miniaturization of the lattice laser emission structure.

Wherein SiO is used as the substrate of the diffractive optical element 24 ₂ A plate, but is not limited thereto.

Further, as described above, the first laser beam is finally used for calculating the depth information, and the first wavelength thereof may be set according to actual requirements. For example, in a face recognition scene, infrared wavelengths of 850nm, 930nm, 940nm, and the like are commonly used. In a scene with low illumination intensity, such as indoors, the photoelectric conversion ratio of 850nm infrared light is higher, and the reflectivity is also higher. In a scene with high illumination intensity, such as outdoors, the 940nm infrared light has higher anti-interference capability, and those skilled in the art can select the anti-interference capability according to actual needs, but the anti-interference capability is not limited to this.

The second laser beam is finally used for identifying and positioning each laser spot in the depth image, the second wavelength of the second laser beam can be set according to actual requirements, and as long as the second wavelength is different from the first wavelength, the position of the second laser spot 311 in the second structured light pattern 31 projected by the second laser beam through the first diffraction grating 241 can be identified in the depth image.

It should be noted that the number of the first laser emitters 21 in the first dot matrix laser emitter 20 and the number of the second laser emitters 23 in the second dot matrix laser emitter 22 may be set according to actual requirements, for example, 243 first laser emitters 21 are set in the first dot matrix laser emitter 20, 2187 first laser spots 301 may be provided in the first structured light pattern 30 formed after being diffracted by the first diffraction grating 241 (taking the diffraction orders in the horizontal direction and the vertical direction as an example, the laser spots expand by 9 times), 2187 first laser spots 301 are projected onto the target object, and the depth information of 2187 points on the target object may be calculated, so as to restore the three-dimensional reconstruction map of the target object, but is not limited thereto.

It can be understood that, in the case that the area of the first dot matrix laser emitter 20 is not changed, the greater the number of the first laser emitters 21, i.e. the denser the first laser emitters 21 are disposed, the denser the first laser spots 301 in the first structured light pattern 30, so as to enhance the accuracy of the target object identification. Meanwhile, under the condition that the area of the second lattice laser emitter 22 is not changed, the more the number of the second laser emitters 23 is, that is, the denser the second laser emitters 23 are arranged, the more the second laser spots 311 in the second structured light pattern 31 are, so that the identification accuracy of the second laser spots 311 in the second structured light pattern 31 can be improved.

In summary, in the lattice laser emitting structure provided by the embodiment of the invention, by setting the first lattice laser emitter and the second lattice laser emitter which have different wavelengths, and the diffractive optical element having the first diffraction grating and the second diffraction grating, the first laser beam emitted by the first lattice laser emitter forms the first structured light pattern through the first diffraction grating, the second laser beam emitted by the second lattice laser emitter forms the second structured light pattern through the second diffraction grating, and the projection area of the first structured light pattern is at least partially overlapped with the projection area of the second structured light pattern, and the second laser spot in the second structured light pattern is staggered with the first laser spot in the first structured light pattern, so that the second laser spot in the second structured light pattern is used as a feature point to realize area recognition.

With continued reference to fig. 4-7, optionally, the number of first laser emitters 21 is greater than the number of second laser emitters 23.

Specifically, as described above, the first laser beam emitted by the first dot matrix laser emitter 20 passes through the first diffraction grating 241 to form the first structured light pattern 30 for calculating the depth information, and the greater the number of the first laser emitters 21 in the first dot matrix laser emitter 20, the denser the first laser spots 301 in the first structured light pattern 30, so that the accuracy of target object identification can be improved.

In the present embodiment, by setting the number of the first laser emitters 21 to be greater than the number of the second laser emitters 23, a greater number of first laser emitters 21 can be provided in the first dot matrix laser emitter 20, so as to ensure the accuracy of target object identification.

For example, as shown in fig. 4 to 7, the first laser emitters 21 and the second laser emitters 23 are arranged in an array, and the ratio of the number of the first laser emitters 21 to the number of the second laser emitters 23 is set to 8, where the area of the first dot matrix laser emitter 20 occupies 80% of the total area, and the area of the second dot matrix laser emitter 22 occupies 20% of the total area. As shown in fig. 7, the first laser emitters 21 and the second laser emitters 23 may be arranged in the row direction, and the lengths of the first laser emitters 21 and the second laser emitters 23 in the column direction are the same, then the ratio between the length of the first laser emitters 21 in the row direction and the length of the second laser emitters 23 in the row direction is 80%:20 percent.

Accordingly, the areas of the first diffraction grating 241 and the second diffraction grating 242 in the diffractive optical element 24 may be correspondingly set according to the areas of the first lattice laser emitter 20 and the second lattice laser emitter 22, and in this embodiment, the area ratio of the first diffraction grating 241 to the second diffraction grating 242 may be set to be 80%:20%, specifically, the first diffraction grating 241 and the second diffraction grating 242 may be arranged in the row direction, the lengths of the first diffraction grating 241 and the second diffraction grating 242 in the column direction are the same, and the ratio between the length of the first diffraction grating 241 in the row direction and the length of the second diffraction grating 242 in the row direction is 80%:20%, but not limited thereto.

With continued reference to fig. 8 and 9, the area ratio between the projected area of the first structured light pattern 30 and the projected area of the second structured light pattern 31 of the zeroth order is 80%:20%, and the area ratio between the projected area of the first structured-light pattern 30 and the projected area of the second structured-light pattern 31 of minus one order is 80%:20%, and the area ratio between the projection area of the first structured light pattern 30 and the projection area of the second structured light pattern 31 of the positive stage is 80%:20 percent. And the transmissive area of the zero-order structured light pattern covers 20% of the negative first-order structured light pattern, such that the projected area of the zero-order first structured light pattern 30 covers the projected area of the negative first-order second structured light pattern 31; the transmissive area of the structured light pattern of the positive first order covers 20% of the structured light pattern of the zero order such that the projected area of the first structured light pattern 30 of the positive first order covers the projected area of the second structured light pattern 31 of the zero order, such that the projected areas of the first structured light patterns 30 of different diffraction orders constitute one complete projected area.

It should be noted that, the larger the number of the second laser emitters 23, the larger the area of the second lattice laser emitter 22, and since the projection area of the first structured light pattern 30 of the adjacent diffraction order needs to cover the projection area of the second structured light pattern 31, the larger the area of the overlap between the projection areas of the structured light patterns of the adjacent diffraction order finally projected through the diffractive optical element 24, which increases the processing difficulty of the diffractive optical element 24. Therefore, in the present embodiment, by setting the number of the first laser emitters 21 to be greater than the number of the second laser emitters 23, the area of the second lattice laser emitter 22 can be made smaller, so as to reduce the area of the required overlap between the projection areas of the structured light patterns of adjacent diffraction orders, so as to reduce the processing difficulty of the diffractive optical element 24, which is easy to implement.

It should be noted that, the above embodiment is only described by taking the example that the ratio of the number of the first laser emitters 21 to the number of the second laser emitters 23 is 8.

The inventor researches and discovers that the damage threshold of the laser wavelength below 380nm and above 1400nm to human eyes is higher, and when the laser wavelength is 400nm to 1100nm and 1500nm to 1700nm, the degree of laser absorption by the atmosphere is lower, so that in the embodiment, the second wavelength λ 1 is set to satisfy that λ 1 is more than or equal to 400nm and less than or equal to 1100nm, so that the damage to the human eyes is smaller, the absorption of the atmosphere to the second laser beam can be reduced, and the characteristic recognition of the second laser spot 311 in the second structured light pattern 31 is facilitated.

Optionally, the second wavelength is greater than the first wavelength, and the grating period of the second diffraction grating 242 is greater than the grating period of the first diffraction grating 241.

Specifically, the molecular radius in the atmosphere is usually less than 1nm, the scattering of light by particles with a linearity less than the wavelength of light is called rayleigh scattering, and the longer the wavelength is, the weaker the scattering is, therefore, in the present embodiment, the second wavelength is set to be greater than the first wavelength, so that the scattering of the second laser beam is weaker, which is beneficial to improving the positioning accuracy of the second structured light pattern 31.

For example, in the present embodiment, the first wavelength may be 930nm, the second wavelength may be 1064nm, which may reduce the absorption of the second laser beam by the atmosphere while causing less damage to the human eye, and the scattering of the second laser beam is weak, which is beneficial for the feature recognition of the second laser spot 311 in the second structured light pattern 31, but is not limited thereto, and those skilled in the art should understand that the first wavelength and the second wavelength are within the protection scope of the present specification when they are other lengths.

Further, the formula for the diffracted light is:

sin ² θsin ² φ+（sinθcosφ+mλ/d） ² ）<n ² ；

wherein, theta and phi are respectively an incident angle and an emergent angle, lambda is a wavelength, m is a diffraction order, d is a grating period, and n is a refractive index. The grating period refers to the distance between the center lines of two adjacent slits in the diffraction grating.

As can be seen from the above formula, when the incident angle is constant, the longer the wavelength is, the larger the grating period can be set, so that in this embodiment, by setting the second wavelength to be greater than the first wavelength, the grating period of the second diffraction grating 242 is greater than the grating period of the first diffraction grating 241, thereby reducing the difficulty in manufacturing the second diffraction grating 242, and facilitating implementation.

Optionally, the grating period of the first diffraction grating 241 is d1, and the grating period of the second diffraction grating 242 is d2, where d1 is less than or equal to 2 μm, and d2 is less than or equal to 2 μm.

Specifically, referring to the above formula, when the lattice laser emitting structure is applied to a VCSEL lattice laser system of a front camera of a mobile phone, the incident angle is usually 0 degrees, so the above formula can be simplified as (m λ/d) ² ＜n ² Using SiO as the diffractive optical element 24 ₂ The material (refractive index n = 1.4) and the first wavelength 940nm are taken as examples, and the substitution formula can calculate that the diffraction can generate + -1 order diffraction under the condition that d is more than lambda/1.4 and is approximately equal to 671nm, and can generate + -2 order diffraction when d is more than 2 lambda/1.4 and is approximately equal to 1343nm, so that the diffraction grating period can generate 3 × 3 matrix structured light through diffraction at 671nm to 1343 nm.

With continued reference to fig. 1-3, in the conventional lattice laser emission structure, the grating period of the circular diffractive optical element 24 '(DOE) is 10 μm, and the diffraction of the laser with the wavelength of 940nm cannot be satisfied, so that the conventional lattice laser emission structure is provided with the optical system 11' (three convex lenses), and the optical system 11 'forms a reduced real image on the DOE, so that the grating period of the image formed by the reduced real image reaches the nanometer level, so that the 940nm laser emitted by the semiconductor laser 10' satisfies the diffraction condition of the circular diffractive optical element 24', but the optical system 11' causes aberration, which results in reduced imaging quality.

In the present embodiment, the grating period d1 of the first diffraction grating 241 and the grating period d2 of the second diffraction grating 242 are both set to be less than or equal to 2 μm, so that the diffractive optical element 24 directly satisfies the diffraction conditions of the first laser beam and the second laser beam, and thus the setting of the optical train can be removed, the aberration generated by the optical train can be eliminated, and the accuracy of target object identification can be improved.

Specific values of the grating period d1 of the first diffraction grating 241 and the grating period d2 of the second diffraction grating 242 may be set according to actual requirements, in some embodiments, the grating period d1 of the first diffraction grating 241 and the grating period d2 of the second diffraction grating 242 may be in a hundred nanometer level, which is not specifically limited in the embodiment of the present invention.

Fig. 12 is a schematic structural diagram of another dot matrix laser emission structure provided in an embodiment of the present invention, fig. 13 is a schematic structural diagram of another dot matrix laser emission structure provided in an embodiment of the present invention, fig. 14 is a schematic structural diagram of a front view of another dot matrix laser emission structure provided in an embodiment of the present invention, and fig. 15 is a schematic structural diagram of a top view of another dot matrix laser emission structure provided in an embodiment of the present invention, as shown in fig. 12 to fig. 15, optionally, the first laser beam and the second laser beam include a first polarized light, the dot matrix laser emission structure provided in an embodiment of the present invention further includes a polarizing plate 27, the polarizing plate 27 is located on a propagation path of the first laser beam and the second laser beam, and a polarization direction of the polarizing plate 27 is the same as a polarization direction of the first polarized light.

The polarized light means that the light vibrates in a certain direction. The first polarized light means polarized light having a set polarization direction.

Different objects or different states of the same object can produce different polarization states, forming different polarization spectra. The traditional infrared technology adopts a light intensity imaging technology, the intensity of radiation of an object is measured, the influence of environmental factors is large, and imaging is difficult to achieve due to the fact that the light intensity is too weak in severe environment.

In this embodiment, by setting the first laser beam and the second laser beam to include the first polarized light, according to the contrast of the object radiation in different polarization directions, the objects with the same radiation intensity and different polarizations can be distinguished by the first polarized light, and a relatively high precision can be achieved without accurate radiation amount calibration, so that the imaging quality can be improved, and the accuracy of target object identification can be enhanced.

The more single the polarization direction of the laser beam is, the higher the imaging quality is, and the image acquisition operation is performed in a severe environment, which has absolute advantages in the aspects of suppressing background noise, improving shooting distance, acquiring detailed features, identifying target camouflage, and the like.

However, in the stage of mass production of the existing dot matrix laser emission structure, it may occur that the light emitted by the laser emitter is partially polarized light, in this embodiment, the polarizing plate 27 is disposed on the propagation paths of the first laser beam and the second laser beam, and the polarization direction of the polarizing plate 27 is the same as the polarization direction of the required first polarized light, so as to perform polarization analysis on the light emitted by the dot matrix laser emission structure, so that the laser beams emitted by the polarizing plate 27 are the first polarized light, thereby improving the linear polarization characteristic of the laser beams emitted by the dot matrix laser emission structure, and contributing to improving the imaging quality.

Alternatively, the polarizer 27 may use a specially doped polymer sheet (composite material) stretched in one direction so that the polymer is aligned in one direction, and the polarization direction of light is strongly absorbed when it coincides with the direction, and the absorption of light perpendicular to the direction is very weak, thereby realizing the function of polarization analysis.

Wherein the polymer plate may be placed on top of a more robust object and provided with marks to indicate the polarization direction corresponding to the maximum transmission.

Based on the same inventive concept, an embodiment of the present invention further provides a dot matrix laser system, fig. 16 is a schematic structural diagram of the dot matrix laser system provided in the embodiment of the present invention, and as shown in fig. 16, the dot matrix laser system 50 includes:

the dot matrix laser emitting structure 51 according to any embodiment of the present invention, the dot matrix laser emitting structure 51 is configured to project a first structured light pattern and a second structured light pattern to a target field of view.

And a camera 52 for acquiring a depth image of the target field of view, the depth image including an image of the first structured light pattern and the second structured light pattern formed on the target object.

And the processor 53 is connected with the dot matrix laser emitting structure 51 and the camera 52 respectively, and is configured to control the dot matrix laser emitting structure 51 to project the first structured light pattern and the second structured light pattern to the target field of view, acquire a depth image of the target field of view through the camera, and calculate depth information of the target object based on the depth image.

The dot matrix laser system 50 may collect depth images of target objects in the target field of view, and calculate depth information.

The target field of view may be the operating range of the dot matrix laser system 50. The target object can be any object to be detected which needs to be subjected to depth information calculation. The dot matrix laser system 50 may be applied to any situation where depth information calculation is required, such as a three-dimensional reconstruction scene, a face recognition scene, an unmanned scene, and the like.

For convenience of illustration, the lattice laser system 50 is described as being applied to a face recognition scene. The face recognition scene may be various scenes that need to perform face recognition on the object to be detected, such as a face payment scene, a face unlocking scene, a face authentication scene, and the like. In a face recognition scenario, the target object may be a face to be recognized.

As shown in fig. 16, the lattice laser system 50 may include the aforementioned lattice laser emitting structure 51, a camera 52, and a processor 53.

The lattice laser emitting structure 51 may be in operative communication with the processor 53. Specifically, the first dot matrix laser transmitter 20 and the second dot matrix laser transmitter 22 of the dot matrix laser emitting structure 51 may be communicatively connected to the processor 53. The processor 53 may control the dot matrix laser emitting structure 51 based on the communication connection to control activation of the first and second dot

matrix laser emitters

20, 22 to project the first and second

structured light patterns

30, 31 toward the target field of view.

The camera 52 may be in operative communication with the processor 53. The camera 52 can be used to convert the captured optical image into an image signal, and the photoelectric conversion function of the photoelectric device is used to convert the optical image on the camera 52 into an electrical signal proportional to the optical image. The camera 52 may acquire a depth image of the target field of view. Specifically, when the target object is within the target field of view, the processor 53 may control the lattice laser emitting structure 51 to project the first and second

structured light patterns

30 and 31 toward the target object, and control the processor 53 to capture an image formed by the target object reflecting the first and second

structured light patterns

30 and 31. That is, the depth image includes images formed by the first structured-light pattern 30 and the second structured-light pattern 31 projected on the target object.

Note that, when the first laser beam and the second laser beam are infrared light, the camera 52 may be a camera capable of capturing infrared light.

The processor 53 may be in operative communication with the dot matrix laser emitting structure 51 and the camera 52 to control the dot matrix laser emitting structure 51 to project the first structured light pattern 30 and the second structured light pattern 31 into the field of view of the target and to receive the depth image captured by the camera 52, and to calculate depth information of the target object based on the depth image. The depth information may include the vertical distance of different locations of the target object from camera 52. The processor 53 may store data or instructions to perform the depth calculation methods described herein and may execute or be used to execute the data and/or instructions. The communication connection refers to any form of connection capable of directly or indirectly receiving information, for example, the communication connection may be a wired connection or a wireless connection, which is not specifically limited in this embodiment of the present invention.

The processor 53 may include a hardware device having a data information processing function and a program necessary for driving the hardware device to operate. Of course, the processor 53 may be only a hardware device having a data processing capability, or only a program running in a hardware device. In some embodiments, processor 53 may include a mobile device, a tablet computer, a laptop computer, a built-in device of a motor vehicle, or the like, or any combination thereof, which is not specifically limited by embodiments of the present invention.

The dot matrix laser system 50 provided in the embodiment of the present invention has the technical effects of the technical solutions in any of the above embodiments, and the structures and terms identical to or corresponding to those in the above embodiments are not repeated herein.

Based on the same inventive concept, an embodiment of the present invention further provides a depth calculation method, which is used in any one of the dot matrix laser systems provided in the embodiments, and the explanation of the same or corresponding structures and terms as those in the embodiments is not repeated herein.

Fig. 17 is a schematic flowchart of a depth calculation method according to an embodiment of the present invention, and as shown in fig. 17, the depth calculation method includes:

and step 110, controlling the dot matrix laser emission structure to project a first structured light pattern and a second structured light pattern to the target field of view.

And 120, acquiring a depth image of the target field of view through the camera, wherein the depth image comprises an image formed by the first structured light pattern and the second structured light pattern on the target object.

Specifically, when the target object is within the target field of view, the processor may control the lattice laser emitting structure to project the first structured light pattern and the second structured light pattern toward the target object, and control the processor to collect an image formed by the target object after reflecting the first structured light pattern and the second structured light pattern.

The depth image of the target field of view obtained by the camera may be, but is not limited to, partial images of the first structured light pattern and the second structured light pattern formed on the target object.

Fig. 18 is a schematic structural diagram of another first structured light pattern and a second structured light pattern provided in an embodiment of the present invention, and as shown in fig. 18, for example, a depth image of a shooting area 60 may be obtained by a camera, where the shooting area 60 is an area of the first structured light pattern and the second structured light pattern that have a periodic structure.

Alternatively, the depth image of the shooting area 60 may be acquired by using a viewing angle difference between the emission viewing angle of the dot matrix laser emission structure and the shooting viewing angle of the camera.

Fig. 19 is a schematic structural diagram of another dot matrix laser system according to an embodiment of the present invention, as shown in fig. 18 and fig. 19, for example, it is explained that the processor may control the dot matrix laser emitting structure 51 to project the first structured light pattern and the second structured light pattern to the test panel 61, fig. 18 may illustrate projection areas of the first structured light pattern and the second structured light pattern formed on the test panel 61, where a height of the dot matrix laser emitting structure 51 hitting the test panel 61 is AD, a height of the camera 52 hitting the test panel 61 is BC, and by adjusting the viewing angles and distances of the dot matrix laser emitting structure 51 and the camera 52, the distance of AB is X1, and the distance of CD is X2, so that the camera 52 can only obtain the depth image of the shooting area 60. That is, the camera 52 only shoots the region having the periodic structure in the first structured light pattern and the second structured light pattern, and the region having the length of X1 (the projection region of the first structured light pattern at the minus stage) and the region having the length of X2 (the projection region of the second structured light pattern at the plus stage) which are additionally provided at both sides of the shooting region 60 are not shot, so that the data processing amount of the processor can be reduced and the calculation speed can be increased, but the invention is not limited thereto.

And step 130, determining the image position of the second structured light pattern formed on the target object in the depth image.

Specifically, fig. 20 is a flowchart of another depth calculating method according to an embodiment of the present invention, and as shown in fig. 20, the second laser spot formed on the target object by the second structured light pattern in the entire depth image 62 can be identified by using a wavelength identification function, so that an image position 63 formed on the target object by the second structured light pattern can be determined.

Step 140, determining the image position of the first structured light pattern formed on the target object in the depth image according to the image position of the second structured light pattern formed on the target object.

With continued reference to fig. 20, using the image locations 63 formed on the target object by the second structured light pattern, the image locations 64 formed on the target object by the first structured light pattern in the depth image can be identified.

Step 150, calculating depth information of the target object according to the image position formed by the first structured light pattern on the target object.

Specifically, the image position of the first structured light pattern formed on the target object includes an image position of each first laser spot in the first structured light pattern formed on the target object, the image of each first laser spot in the first structured light pattern formed on the target object is in one-to-one correspondence with the first laser transmitter in the first dot matrix laser transmitters, and the depth information of the first laser spot formed on the target object by each first laser transmitter is calculated. For example, when a first laser transmitter in a first dot matrix laser transmitter is numbered and depth information of a first laser spot formed on a target object by a first laser transmitter No. 1 is calculated, assuming that coordinates of the first laser transmitter No. 1 in the first dot matrix laser transmitter are (3, 4), the same coordinate system can be established in each of 9 areas, and the first laser spot image of the (3, 4) coordinates in each area is found to calculate the depth information respectively. And further, the depth information of the target object is obtained by calculating the depth information of the first laser spots formed on the target object by each first laser transmitter.

For example, taking the diffraction orders in the horizontal direction and the vertical direction as an example (the laser spots are expanded by 9 times), the image formed by the second structured light pattern on the target object includes 9 image areas, and the second laser spot position formed by each second laser emitter in each image area in the second lattice laser emitter can be identified according to the comparison between the shape of each image area on the target object and the distribution shape of the second laser emitters in the second lattice laser emitter, because the pattern does not change after the second laser spots are diffracted by 9 equal parts.

After the second laser spot position formed by each second laser emitter in each image area is identified, the left area of the second laser spot position is the image area formed on the target object by the first structured light pattern emitted by the corresponding first dot-matrix laser emitter, the shape of the image area formed by the first structured light pattern on the target object is compared with the distribution shape of the first laser emitters in the first dot-matrix laser emitters, and the first laser spot position formed by each first laser emitter in each image area can be identified.

It should be noted that, on the target object, the second laser spots in the second structured light pattern are inserted between the first laser spots in the first structured light pattern, and the first laser spots and the second laser spots do not coincide with each other, so that the positions of the first laser spots formed by each first laser emitter in each image area can be distinguished.

After the depth information of the target object is calculated, a three-dimensional reconstruction map can be performed according to the depth information of each first laser spot, and functions such as target object identification are achieved.

Optionally, before controlling the dot matrix laser emitting structure to project the first structured light pattern and the second structured light pattern to the target field of view, the method further includes:

and controlling the lattice laser emitting structure to project the first structured light pattern and the second structured light pattern to the reference object.

And acquiring a reference depth image of the reference object through the camera, wherein the reference depth image comprises an image formed by the first structured light pattern and the second structured light pattern on the reference object.

Calculating depth information of the target object from the image position formed by the first structured-light pattern on the target object, including:

based on the reference depth image, depth information of the target object is calculated from the image position formed on the target object by the first structured-light pattern.

Specifically, the processor may control the lattice laser emitting structure to project the first structured light pattern and the second structured light pattern to the reference object, and control the processor to collect an image formed by the reference object after reflecting the first structured light pattern and the second structured light pattern, and further generate the reference depth image.

Wherein the depth information of the reference object is known.

In calculating the depth information of the target object from the image position of the first structured-light pattern formed on the target object, the calculation may be performed by a triangulation method based on the reference depth image.

Specifically, the depth image of the target view field shot by the actual camera is compared with the reference depth image, and the depth information of each first laser spot in the depth image of the target view field is calculated, so that the functions of face recognition and the like can be achieved.

Fig. 21 is a schematic structural diagram of a depth calculation method according to an embodiment of the present invention, as shown in fig. 21, for example, coordinates O (0, 0) and W (b, 0) may be obtained from fig. 21.

Let OE = x ₀ Then F (x) ₀ ，z ₀ )。

Delta WEF-delta WHI, the following can be obtained: FE/IH = WE/WH, i.e. z ₀ /z=(b-x ₀ ) WH, available WH = z (b-x) ₀ )/z ₀ Obtainable I (b-z (b-x) ₀ )/z ₀ ，z)。

Assuming that the linear OI point function is y = kx, the I coordinate is substituted to obtain:

k=z/(b-z(b-x ₀ )/z ₀ ) I.e. y = zx/(b-z (b-x) ₀ )/z ₀ )。

Let y = z ₀ Substituting to obtain: x = (b-z (b-x) ₀ )/z ₀ )z ₀ /z=(z ₀ b-z(b-x ₀ ))/z。

Available G ((z) ₀ b-z(b-x ₀ ))/z，z ₀ )。

Δ OJF- Δ OFG, obtaining: f/z ₀ And = e/GF, substituting to obtain:

f/z ₀ =e/(x ₀ -(z ₀ b-z(b-x ₀ ))/z)=e/(zx ₀ -z ₀ b+z(b-x ₀ ))/z)=e/(-z ₀ b+zb)/z)=e/(b-z ₀ b/z)。

the following can be obtained through simplification: z = z ₀ /(1-z ₀ e/fb)。

The formula: z = z ₀ /(1-z ₀ e/fb) of ₀ In order to capture the distance of the reference object 65, b is the distance between the dot matrix laser emitting structure 51 and the camera 52, f is the effective focal length of the camera 52, and e is how many pixels are away from the sensor of the camera 52 in the capturing of the reference object 65 and the actual capturing of the target object 66 by the same first laser spot.

By calculating the pixel value of the distance between the image of each first laser spot in the photographing reference object 65 and the image of the actual photographing target object 66, the actual depth of each first laser spot can be calculated, thereby realizing the function of three-dimensional reconstruction.

Optionally, acquiring a reference depth image of the reference field of view by using a camera includes:

and acquiring a periodic depth image of the reference object through the camera, wherein the periodic depth image is a partial image of the first structured light pattern and the second structured light pattern which are periodically distributed in the image formed on the reference object.

And acquiring a reference depth image according to the periodic depth image, wherein the size of the reference depth image is larger than that of the periodic depth image.

Fig. 22 is a schematic structural diagram of a first structured light pattern and a second structured light pattern provided by an embodiment of the present invention, fig. 23 is a schematic structural diagram of a dot matrix laser system provided by an embodiment of the present invention, fig. 22 can illustrate projection areas of the first structured light pattern and the second structured light pattern formed on a reference object 65, as shown in fig. 22 and fig. 23, when the reference object 65 is photographed by a camera, a depth image of a photographing area 67 can be acquired by the camera, and a periodic depth image is obtained, where the photographing area 67 is an area of the first structured light pattern and the second structured light pattern that has a periodic structure, that is, the periodic depth image has a periodic structure.

With continued reference to fig. 19, a depth image of the photographing region 67 may be acquired using a viewing angle difference between the emission viewing angle of the dot matrix laser emission structure and the camera photographing viewing angle.

Illustratively, as shown in fig. 19, the height of the dot matrix laser emission structure 51 hitting the reference object 65 is AD, the height of the camera 52 hitting the reference object 65 is BC, and the distance of AB is X1 and the distance of CD is X2 by adjusting the viewing angles and distances of the dot matrix laser emission structure 51 and the camera 52, so that the camera 52 can only acquire the depth image of the shooting area 67. That is, the camera 52 only shoots the region having the periodic structure in the first structured light pattern and the second structured light pattern, and the region having the length of X1 (the projection region of the first structured light pattern at the minus level) and the region having the length of X2 (the projection region of the second structured light pattern at the plus level) which are protruded at both sides of the shooting region 67 are not shot, so that the data processing amount of the processor can be reduced and the calculation speed can be increased, but not limited thereto.

Fig. 24 is a flowchart illustrating a further depth calculating method according to an embodiment of the present invention, as shown in fig. 24, after the periodic depth image 68 is acquired, the imaging areas of the first structured light pattern and the second structured light pattern are respectively supplemented to the left and the right of the periodic depth image 68 by using the actual regularity of the light spot distribution in the shooting area 67, so that the periodic structure of the periodic depth image 68 is changed from the actual 3 × 2 structure to the 3 × 4 structure, thereby generating a reference depth image 69, and the data of the reference depth image 69 is stored in the processor for use in the triangulation method for identifying the actual target object.

It should be noted that, in an actual face recognition scene, the lattice laser system has an effective recognition distance range, and the effective recognition distance range is usually 10cm to 60cm, that is, the distance between the camera and the face is 10cm to 60cm, but the present invention is not limited thereto.

When the distance between the camera and the face is short, the image of the pattern formed by the second structured light pattern on the face in the camera is small; when the distance between the camera and the face is long, the image of the pattern formed on the face by the second structured light pattern in the camera is large; in this embodiment, the size of the obtained reference depth image is larger than that of the periodic depth image by supplementing the periodic depth image, so that when the distance between the camera and the face is relatively long, each pixel point in the obtained depth image of the target object can find a corresponding pixel point in the reference depth image for comparison, and the identification accuracy of the target object is ensured.

It should be understood that various forms of the flows shown above may be used, with steps reordered, added, or deleted. For example, the steps described in the present invention may be executed in parallel, sequentially, or in different orders, and are not limited herein as long as the desired result of the technical solution of the present invention can be achieved.

The above-described embodiments should not be construed as limiting the scope of the invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made, depending on design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A lattice laser emitting structure, comprising:

the projection area of the first structured light pattern is a first projection area, the projection area of the second structured light pattern is a second projection area, the first projection area and the second projection area are at least partially overlapped, and second laser spots in the second structured light pattern and first laser spots of the first structured light pattern are arranged in a staggered mode;

the second structured-light pattern is used to determine the position of the first structured-light pattern.

2. The lattice laser emission structure of claim 1,

the number of the first laser emitters is greater than the number of the second laser emitters.

3. The lattice laser emission structure of claim 1,

the second wavelength is lambda 1, wherein lambda 1 is more than or equal to 400nm and less than or equal to 1100nm.

4. The lattice laser emission structure of claim 2,

the second wavelength is greater than the first wavelength;

5. The lattice laser emission structure of claim 1,

the grating period of the first diffraction grating is d1, the grating period of the second diffraction grating is d2, wherein d1 is less than or equal to 2 micrometers, and d2 is less than or equal to 2 micrometers.

6. The lattice laser emission structure of claim 1,

the first laser beam and the second laser beam comprise first polarized light;

the lattice laser emission structure further comprises a polaroid;

the polarizing plate is located on a propagation path of the first laser beam and the second laser beam, and the polarization direction of the polarizing plate is the same as the polarization direction of the first polarized light.

7. A lattice laser system, comprising:

the lattice laser emitting structure of any one of claims 1-6, for projecting a first structured light pattern and a second structured light pattern toward a target field of view;

8. A depth calculation method for the lattice laser system of claim 7, the depth calculation method comprising:

acquiring a depth image of the target field of view through a camera, wherein the depth image comprises images of the first structured light pattern and the second structured light pattern formed on a target object;

determining an image position of the second structured light pattern formed on the target object in the depth image by using wavelength recognition;

9. The depth calculation method according to claim 8,

before controlling the dot matrix laser emitting structure to project the first structured light pattern and the second structured light pattern to the target field of view, the method further comprises:

acquiring a reference depth image of the reference object by the camera, wherein the reference depth image comprises images of the first structured light pattern and the second structured light pattern formed on the reference object;

10. The depth calculation method according to claim 9,

acquiring a reference depth image of the target object through the camera, including:

acquiring a periodic depth image of the target object through the camera, wherein the periodic depth image is a partial image in which the first structured light pattern and the second structured light pattern are periodically distributed in an image formed on the reference object;