CN219778049U - Speckle projector, depth camera and electronic equipment - Google Patents

Abstract

The utility model relates to the technical field of three-dimensional sensing, and discloses a speckle projector, a depth camera and electronic equipment. The speckle projector is used for projecting a speckle pattern, the speckle pattern comprises a central area and an edge area positioned outside the central area, and the speckle projector comprises a light source, a collimation element and a diffraction optical element. The light source is used for emitting light beams; the collimating element is used for collimating the light beam; the diffraction optical element is used for copying the collimated light beam and projecting a first speckle sub-pattern and a second speckle sub-pattern; wherein, the first speckle of the first speckle sub-pattern is distributed in the central area and the edge area, and the second speckle of the second speckle sub-pattern is distributed in the edge area. In the speckle pattern projected by the speckle projector, the first speckle and the second speckle are arranged in the edge area, the density of the speckle in the edge area is not too sparse, and the algorithm requirement of depth calculation can be met.

Description

Speckle projector, depth camera and electronic equipment

Technical Field

The utility model relates to the technical field of three-dimensional sensing, in particular to a speckle projector, a depth camera and electronic equipment.

Background

Common depth cameras include structured light depth cameras and active binocular depth cameras. Because of the wide field angle requirements of the application scene of the depth camera, the development of the structured light depth camera and the active binocular depth camera is becoming more and more urgent in the development of a large viewing angle.

Currently, speckle projectors for structured light or active binocular depth cameras include Vertical-Cavity Surface-Emitting lasers (VCSELs), collimating elements, and diffractive optical elements (Diffractive Optical Elements, DOEs). Laser emitted by the VCSEL is collimated by the collimating element and then enters the DOE, the DOE is copied into a plurality of parts, and the parts are projected to the space to form relatively uniform and random laser scattered spots. Since the DOE is a special grating, the angle of DOE diffraction is determined by factors such as wavelength and grating period, and if the wavelength and grating period are determined, the diffraction angle is also fixed. As the angle of view increases, the distance between the scattered spots projected onto the space from the edge increases, resulting in a very sparse scattered spots in the edge area of the projected speckle pattern, which cannot meet the algorithm requirements.

Disclosure of Invention

In view of the above, the utility model provides a speckle projector, a depth camera and an electronic device, which can solve the technical problem of sparse speckle density in the edge area of a projected speckle pattern.

In a first aspect, an embodiment of the present utility model provides a speckle projector for projecting a speckle pattern, the speckle pattern comprising a central region and an edge region located outside the central region, the speckle projector comprising a light source, a collimating element, and a diffractive optical element. The light source is used for emitting light beams; the collimating element is used for collimating the light beam; the diffraction optical element is used for copying the collimated light beam and projecting a first speckle sub-pattern and a second speckle sub-pattern; wherein, the first speckle of the first speckle sub-pattern is distributed in the central area and the edge area, and the second speckle of the second speckle sub-pattern is distributed in the edge area.

In some embodiments, the light source comprises a first sub-light source and a second sub-light source separately powered, the first sub-light source and the second sub-light source comprising a plurality of first light emitting spots and a plurality of second light emitting spots, respectively, the first light emitting spots and the second light emitting spots being staggered with respect to each other. In some embodiments, within the edge region, a portion of the plurality of second scattered spots is located in a gap between two first scattered spots, and the first scattered spots do not overlap with the second scattered spots.

In some embodiments, the diffractive optical element comprises a first diffractive unit and a second diffractive unit: the first diffraction unit is used for diffracting the collimated light beam and then projecting a first speckle sub-pattern; the second diffraction unit is used for diffracting the collimated light beam and projecting a second speckle sub-pattern. In some of these embodiments, the second diffractive element is located at an edge region or side of the first diffractive element. In some of these embodiments, the first diffractive unit comprises a plurality of first diffractive structures arranged in a first array; the second diffraction unit comprises a plurality of second diffraction structures, and the second diffraction structures are positioned on at least one side of the first diffraction unit. In some embodiments, the second diffraction unit includes a first diffraction subunit and a second diffraction subunit, where each of the first diffraction subunit and the second diffraction subunit includes a plurality of second diffraction structures, the first diffraction subunit is disposed on one side or two opposite sides of the first diffraction unit in a horizontal direction, and the second diffraction subunit is disposed on one side or two opposite sides of the first diffraction unit in a vertical direction. In an embodiment, the second diffractive structure is offset from the adjacent first diffractive structure in the row and/or column direction.

In a second aspect, an embodiment of the present utility model provides a depth camera, including the aforementioned speckle projector and an acquisition module; the speckle projector is used for projecting speckle patterns, and the acquisition module is used for acquiring the speckle patterns.

In a third aspect, an embodiment of the present utility model provides an electronic device, including the depth camera of the foregoing embodiment.

The technical scheme provided by the utility model has the beneficial effects that: after the diffraction optical element replicates the collimated light beam, a first speckle sub-pattern and a second speckle sub-pattern are projected, wherein the first speckle in the first speckle sub-pattern is distributed in a central area and an edge area, and the second speckle in the second speckle sub-pattern is distributed in the edge area, so that the first speckle and the second speckle are arranged in the edge area, the density of the speckle in the edge area is higher, the speckle is not too sparse, and the algorithm requirement of depth calculation can be met.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a depth camera according to the present utility model;

FIG. 2 is a schematic diagram of a speckle projector according to the present utility model;

FIG. 3 is a schematic diagram of a light source array according to the present utility model;

FIG. 4 is a schematic view of a speckle pattern projected when a single point light source is turned on in a speckle projector according to the related art;

FIG. 5A is a schematic diagram of a first speckle sub-pattern projected by a single point light source in a speckle projector according to the present utility model;

FIG. 5B is a schematic diagram of a second speckle sub-pattern projected by a single point light source in the speckle projector according to the present utility model;

FIG. 5C is a schematic view of a first speckle pattern projected by a single point light source in a speckle projector according to the present utility model;

fig. 6 is a schematic diagram of diffraction structure distribution of the diffractive optical element provided by the present utility model.

Detailed Description

In order that those skilled in the art will better understand the present utility model, a technical solution in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present utility model and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the utility model described herein may be implemented in sequences other than those illustrated or otherwise described herein.

It should be further understood that the terms "right" and "left" and the like indicate an orientation or a positional relationship based on the orientation or the positional relationship shown in the drawings, and are merely for convenience of description and simplification of description, and do not indicate or imply that the apparatus or element to be referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the utility model.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a depth camera according to an embodiment of the utility model. The depth camera 10 includes a speckle projector 110, an acquisition module 120, and a control and processor 130. Wherein the speckle projector 110 is used to project a speckle pattern into space; the acquisition module 120 is used for acquiring speckle patterns in the space to generate speckle images; the control and processor 130 is configured to match the speckle image with a pre-stored reference speckle image, calculate a deviation value, and obtain depth information, and generate a depth image. Alternatively, the depth camera may not include the control and processor 130, and the depth information may be calculated by an external processor or device. The depth camera 10 may be provided inside the electronic device, and the processor of the electronic device calculates depth information to generate a depth image.

In the related art, the speckle projector comprises a light source, a collimation element and a DOE, wherein a light beam emitted by the light source is collimated by the collimation element and then enters the diffraction optical element, a plurality of copies are copied by the DOE, and if the view angle of the speckle projector is larger, the speckle density of the edge area is obviously lower than that of the central area in the speckle pattern projected. As shown in fig. 4, fig. 4 is a schematic view of a speckle pattern projected when a single point light source is turned on in a speckle projector in the related art, and it can be seen that the speckle density of the edge area 42 (the area between the solid line frame and the dotted line frame in the figure) is significantly lower than that of the center area 41 (the area framed by the dotted line frame in the figure), and the speckle density of the edge area 42 is too low to satisfy the requirement of the depth calculation algorithm.

The speckle pattern projected by the speckle projector 110 of the present utility model includes a center region and an edge region outside the center region. As shown in fig. 2 and 5A to 5C, the speckle projector 110 includes a light source 111, a collimator element 112, and a diffractive optical element 113. The light source 111 may be a light source array composed of a plurality of point light sources for generating a light beam; the collimating element 112 is disposed in the emission path of the light source 111, and is used for collimating the light beam; wherein the collimating element 112 may comprise one or more lenses, which may be concave lenses, convex lenses, etc., without limitation. The diffractive optical element 113 is disposed in the projection path of the collimating element 112, and is configured to copy the light beam into several portions, and project the portions onto the front space to form a first speckle sub-pattern (as shown in fig. 5A) and a second speckle sub-pattern (as shown in fig. 5B), wherein the first speckle 501 in the first speckle sub-pattern is distributed in the central region 51 (in the area between the dashed line frame and the solid line frame in the figure) and the edge region 52 (in the area between the dashed line frame and the solid line frame in the figure), and the second speckle 502 in the second speckle sub-pattern is distributed in the edge region 52.

As shown in fig. 3, in some embodiments, the light source 111 is a light source array, and the light source array includes a first sub-light source and a second sub-light source, where the first sub-light source includes a plurality of first light emitting points 1112 and the second sub-light source includes a plurality of second light emitting points 1114, and the first light emitting points 1112 and the second light emitting points 1114 are represented by black filled dots and white filled dots, respectively, in fig. 3. The first luminous points 1112 and the second luminous points 1114 are staggered and layered, and the first sub-light source and the second sub-light source are respectively and independently powered, and the first sub-light source and the second sub-light source can be independently controlled to be independently turned on or turned on simultaneously, so that the requirements on the precision of materials and manufacturing processes are low, and the turning on of the first sub-light source and the second sub-light source can be controlled according to different scenes so as to project speckle patterns with different speckle densities.

For example, when the depth of a small object is required to be acquired or in a long-distance scene, the first sub-light source and the second sub-light source are simultaneously started, and the speckle density of the projected speckle pattern is higher; in a short-distance scene, the first sub-light source or the second sub-light source is started, the projected scattered spots have strong energy, scattered spots in the scattered spot image acquired by the acquisition module 120 are large, and if the first sub-light source and the second sub-light source are started at the same time, the scattered spots are easy to adhere together, so that only the first sub-light source or the second sub-light source is started, and the accuracy is ensured while the power consumption is lower. According to the utility model, the first sub-light source and the second sub-light source which are arranged in a staggered manner are arranged, so that the depth camera can be suitable for different application scenes.

As shown in fig. 5A to 5C, fig. 5A, 5B and 5C are schematic diagrams of the first speckle sub-pattern, the second speckle sub-pattern and the speckle pattern projected by the speckle projector 110 when the single point light source in the light source 111 is turned on. The speckle projector 110 can project a plurality of first speckle 501 (solid black filled speckle in the figure) to form a first speckle sub-pattern, as shown in fig. 5A; the speckle projector 110 also projects a plurality of second speckle 502 (shadow filled speckle in the figure) to form a second speckle sub-pattern, as shown in fig. 5B; the first speckle sub-pattern and the second speckle sub-pattern combine to form a speckle pattern, as shown in fig. 5C. Wherein the first scattered spots 501 are distributed in the central area 51 and the edge area 52, the second scattered spots 502 are distributed in the edge area 52, and the second scattered spots 502 are distributed among the plurality of first scattered spots 501.

It can be seen from fig. 5 that the first average speckle density of the first speckle sub-pattern in the central region 51 is smaller than the second average speckle density in the edge region 52. Since the second speckle pattern is distributed in the edge region 52, the second speckle sub-pattern at least partially overlaps, e.g., partially overlaps or completely overlaps, the edge region of the first speckle sub-pattern, and the speckle density of the speckle pattern in the edge region 52 is not too sparse as in fig. 4, as shown in fig. 5, and the speckle density in the edge region 52 is significantly higher than in the edge region shown in fig. 4. In the speckle pattern of the present utility model, the speckle density in the edge region 52 may be close to or greater than that of the center region 51, and thus the edge region 52 may also satisfy the requirements of the depth calculation algorithm. The diffractive optical element 113 may be designed such that the first speckle 501 and the second speckle 502 do not overlap, so that there is no adhesion between the speckle projected by the speckle projector 110, and the depth calculation is not affected.

As shown in FIG. 5, the second speckle pattern 502 is distributed only in the edge region 52, so that the speckle density of the edge region 52 in the speckle pattern is improved and can be nearly identical to that of the center region 51. In some embodiments, the second speckle pattern 502 is not distributed in the central region 51 to avoid excessive speckle and excessive brightness in the central region 51 of the speckle pattern. The division of the central area 51 and the edge area 52 is not particularly limited in the present utility model, and the central area 51 may be the area of 50%, 60%, 70% or the like in the middle of the entire speckle pattern, and the edge area 52 may be the peripheral area of the central area 51.

The diffractive optical element 113 may be designed according to the target speckle pattern to be projected by the speckle projector 110 and the distribution of the light emitting points on the light source 111, so that the diffractive optical element 113 can project the first speckle sub-pattern and the second speckle sub-pattern after copying the collimated light beam. For example, the phase distribution of the diffractive optical element 113 may be calculated according to the speckle pattern and the distribution of the light source, and the microstructure of the diffractive optical element 113 may be designed so that the diffractive optical element 113 may project the first speckle sub-pattern and the second speckle sub-pattern.

In some embodiments, as shown in fig. 6, fig. 6 is a schematic structural diagram of the spot of the diffractive optical element 113 according to the present utility model. As can be seen from fig. 6, the diffractive optical element 113 includes a first diffractive unit 1131 and a second diffractive unit 1132. The first diffraction unit 1131 is configured to diffract the light beam collimated by the collimating element 112 to project a first speckle sub-pattern, and the second diffraction unit 1132 is configured to diffract the light beam collimated by the collimating element 112 to project a second speckle sub-pattern.

In one embodiment, the first speckle sub-pattern is pre-designed, and then the first diffraction cell 1131 is reverse designed according to the first speckle sub-pattern; a second speckle sub-pattern is designed in advance, and a second diffraction unit 1132 is designed reversely according to the second speckle sub-pattern; the diffractive optical element 113 is designed in combination with the first diffraction unit 1131 and the second diffraction unit 1132.

The first diffraction unit 1131 includes a plurality of first diffraction structures 1311 (illustrated by dots filled with pure black), and the plurality of first diffraction structures 1311 are arranged in a first array, and the first diffraction structures 1311 are used to diffract the collimated light beam. For example, the first array may be an a-row b-column array, where adjacent columns and adjacent rows of first diffractive structures 1311 are staggered to provide a certain randomness to the distribution of speckle in the projected first speckle sub-pattern. That is, all of the first diffraction structures 1311 are not on the same horizontal or vertical line, and the plurality of first speckle 501 in the first speckle sub-pattern has randomness to effectively prevent a phenomenon of a matching error at the time of depth calculation.

The second diffraction unit 1132 is disposed at an edge region or side of the first diffraction unit 1131. The second diffraction unit 1132 may include a plurality of second diffraction structures 1320 (illustrated with hatched dots), and the second diffraction structures 1320 are used to diffract the collimated light beam. The second diffraction unit 1132 may be divided into a first diffraction sub-unit 1321 and a second diffraction sub-unit 1322 according to the distribution of the second diffraction structures 1320, and the plurality of second diffraction structures 1320 in the first diffraction sub-unit 1321 are arranged in a second array, which may be an array of c rows and d columns; the plurality of second diffraction structures 1320 in the plurality of second diffraction sub-cells 1322 are arranged in a third array, which may be an e-row f-column array. Wherein some or all of the first diffraction sub-units 1321 are located on at least one side, e.g., one side or opposite sides, of the first diffraction unit 1131 in the horizontal direction, such that the second speckle sub-pattern may coincide with the left and/or right side edge regions of the first speckle sub-pattern; and/or, some or all of the second diffraction sub-units 1322 are disposed on at least one side, e.g., one side or opposite sides, of the first diffraction unit 1131 in the vertical direction, such that the second speckle sub-pattern may coincide with the upper side edge region and/or the lower side edge region of the first diffraction sub-pattern.

Adjacent rows and adjacent columns of the plurality of second diffraction structures 1320 in the first diffraction sub-unit 1321 and the second diffraction sub-unit 1322 are arranged in a staggered manner, so that each second speckle in the second speckle sub-pattern has better randomness. In addition, the second diffraction structures 1320 need to be offset from the adjacent first diffraction structures 1311, so that there is a better uncorrelation between the second speckle in the second speckle sub-pattern and the first speckle in the first speckle sub-pattern, so as to further improve the accuracy of the depth measurement.

In the embodiment shown in fig. 6, the second diffraction unit 1132 includes two sets of first diffraction sub-units 1321 and two sets of second diffraction sub-units 1322, the plurality of second diffraction structures 1320 of the first diffraction sub-units 1321 are arranged in a second array, and the plurality of second diffraction structures 1320 of the second diffraction sub-units 1322 are arranged in a third array. Two sets of first diffraction sub-units 1321 are respectively distributed on the left and right sides of the first diffraction unit 1131 in the horizontal direction, and two sets of second diffraction sub-units 1322 are respectively distributed on the upper and lower sides of the first diffraction unit 1131 in the vertical direction. In this way, the second speckle sub-pattern will overlap with all of the left, right, upper and lower edge regions of the first speckle sub-pattern, so that the overall speckle pattern edge region speckle density is not too low.

The first diffraction structure 1311 and the second diffraction structure 1320 are shown in fig. 6 as solid black filled dots and shaded filled dots, respectively, and the actual first diffraction structure 1311 and second diffraction structure 1320 are not one dot, but have a microstructure with a certain shape and period. Wherein the first and second diffractive structures 1311, 1320 are different in shape and/or period; and/or the first and second diffractive structures 1311, 1320 are located in the same layer or different layers.

In one embodiment, the depth camera may also include a color camera module or the like so that the depth camera module may acquire color images.

The embodiment of the utility model also provides electronic equipment, which comprises the depth camera in any embodiment. As a non-limiting example, the electronic device may include a smart door lock, a robot, a 3D printer, a cell phone, a notebook, a tablet, an industrial measurement device, and the like.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.

The foregoing description of the preferred embodiments of the utility model is not intended to limit the utility model to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the utility model are intended to be included within the scope of the utility model.

Claims (9)

1. A speckle projector for projecting a speckle pattern, the speckle pattern comprising a central region and an edge region located outside the central region, the speckle projector comprising:

the light source is used for emitting light beams, the light source comprises a first sub-light source and a second sub-light source which are separately powered, the first sub-light source and the second sub-light source respectively comprise a plurality of first luminous points and a plurality of second luminous points, and the first luminous points and the second luminous points are staggered;

a collimating element for collimating the light beam;

a diffraction optical element for copying the collimated light beam and projecting a first speckle sub-pattern and a second speckle sub-pattern;

the first speckle of the first speckle sub-pattern is distributed in the central area and the edge area, and the second speckle of the second speckle sub-pattern is distributed in the edge area.

2. The speckle projector of claim 1, wherein portions of the plurality of second speckle are located in a gap between two of the first speckle, and wherein the first speckle and the second speckle do not overlap.

3. The speckle projector of claim 1 or 2, wherein the diffractive optical element comprises:

a first diffraction unit for diffracting the collimated light beam and then projecting the first speckle sub-pattern;

and the second diffraction unit is used for diffracting the collimated light beam and then projecting the second speckle sub-pattern.

4. The speckle projector of claim 3, wherein the second diffraction cell is located on at least one side of the first diffraction cell.

5. The speckle projector of claim 3, wherein the first diffraction cell comprises a plurality of first diffraction structures arranged in a first array; the second diffraction unit comprises a plurality of second diffraction structures, and the second diffraction structures are distributed on at least one side of the first diffraction unit.

6. The speckle projector of claim 5, wherein the second diffraction unit comprises a first diffraction subunit and a second diffraction subunit, each of the first diffraction subunit and the second diffraction subunit comprises a plurality of the second diffraction structures, the first diffraction subunit is disposed on one side or two opposite sides of the first diffraction unit in the horizontal direction, and the second diffraction subunit is disposed on one side or two opposite sides of the first diffraction unit in the vertical direction.

7. The speckle projector of claim 5, wherein the second diffractive structure is offset from the adjacent first diffractive structure in a row and/or column direction.

8. A depth camera, comprising:

the speckle projector of any one of claims 1 to 7, for projecting the speckle pattern;

and the acquisition module is used for acquiring the speckle pattern.

9. An electronic device comprising the depth camera of claim 8.