Optical module, 3D identification system and sweeping robot

Abstract

The application discloses an optical module, a 3D identification system and a sweeping robot. The optical module comprises a shell, a light source assembly, a diffraction element and an adjusting element. The shell is formed with a containing cavity and an opening communicating with the containing cavity. The light source assembly is arranged in the containing cavity. The diffraction element is arranged in the containing cavity. The light emitted by the light source assembly is incident on the diffraction element. The adjusting element is arranged on the opening and is spaced apart from the diffraction element. The adjusting element is used for reducing the distortion generated after the light passes through the diffraction element. The optical module adopts the mode of the diffraction element plus the adjusting element, instead of the mode of multiple projectors in the prior art, so that the manufacturing cost is reduced.

Description

Technical Field

[0001] This application relates to the field of optical module technology, and in particular to an optical module, a 3D recognition system, and a sweeping robot. Background Technology

[0002] In related technologies, for 3D recognition systems that require visual recognition of environmental objects, multiple projectors are generally used in combination to increase the field of view. However, using multiple projectors increases the manufacturing cost of the 3D recognition system. Utility Model Content

[0003] The main purpose of this application is to propose an optical module, a 3D recognition system, and a robotic vacuum cleaner, aiming to at least improve the technical problem of high manufacturing cost of current 3D recognition systems.

[0004] To achieve the above objectives, according to some embodiments of this application, this application provides an optical module, including: A housing having a receiving cavity and an opening communicating with the receiving cavity; A light source assembly is disposed within the receiving cavity. A diffraction element is disposed within the receiving cavity, and light emitted from the light source assembly is incident on the diffraction element; An adjustment element is provided, which covers the opening and is spaced apart from the diffraction element. The adjustment element is used to reduce the distortion of light after it passes through the diffraction element.

[0005] In some embodiments, the adjustment element includes a fisheye lens, the diffraction element causes the light to produce pincushion distortion, and the adjustment element is capable of causing the light to produce barrel distortion, so that the adjustment element can reduce the pincushion distortion of the light after passing through the diffraction element.

[0006] In some embodiments, the fisheye lens includes a first lens, a correction lens, and a second lens stacked together, with the first lens disposed close to the diffraction element.

[0007] In some embodiments, the adjustment element includes a beam-expanding superlens mounted on the opening, the beam-expanding superlens including a substrate and an array of nanostructures disposed on one side of the substrate.

[0008] In some embodiments, the nanostructure is disposed on the side of the substrate away from the diffraction element; or, the nanostructure is disposed on the side of the substrate facing the diffraction element.

[0009] In some embodiments, the regulating element further includes an antireflection film disposed on the side of the substrate opposite to the nanostructure.

[0010] In some embodiments, the housing includes a base plate and a side enclosure surrounding the base plate, the base plate and the side enclosure cooperating to form the receiving cavity, and the side enclosure being coated with a light-shielding layer.

[0011] In some embodiments, the light source assembly includes a light source and a refractive prism. The light source is disposed on the sidewall, and the diffraction element is disposed on the light emission path from the light source to the refractive prism. The light emitted by the light source is diffracted by the diffraction element and then refracted by the refractive prism before entering the adjustment element.

[0012] In some embodiments, a mounting base is provided on the base plate, and a first slide rail and a second slide rail are provided on the mounting base. The refractive prism is slidably mounted on the first slide rail, and the diffraction element is slidably mounted on the second slide rail.

[0013] According to some embodiments of this application, this application provides a 3D recognition system, including a projection module, an image acquisition module, and a three-dimensional reconstruction module. The projection module includes the optical module described above, and the projection module is used to emit light to the surrounding environment through the optical module. The image acquisition module is used to acquire depth image information of the surrounding environment, and the three-dimensional reconstruction module is used to reconstruct the depth image information to obtain a three-dimensional model of the environment.

[0014] According to some embodiments of this application, this application provides a sweeping robot, which includes the 3D recognition system described above, and also includes a path planning module, which is used to generate a movement path based on the three-dimensional environmental model.

[0015] In the above solution, the optical module includes a housing, a light source assembly, a diffraction element, and an adjustment element. The housing forms a receiving cavity and an opening communicating with the receiving cavity. The light source assembly and the diffraction element are disposed within the receiving cavity. Light emitted from the light source assembly is incident on the diffraction element. The adjustment element covers the opening and is spaced apart from the diffraction element. The adjustment element is used to reduce the distortion caused by light passing through the diffraction element. By adding an adjustment element on top of the diffraction element, the adjustment element can adjust the distortion caused by the diffraction element, specifically reducing the distortion. This ensures that the optical module has a large field of view while reducing the resulting distortion, improving the accuracy and reliability of environmental object measurement. This application uses a diffraction element plus an adjustment element, replacing the multiple projectors used in the prior art, thus reducing manufacturing costs.

[0016] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of an optical module according to some embodiments of this application; Figure 2 This is another structural schematic diagram of the optical module of some embodiments of this application; Figure 3 This is yet another structural schematic diagram of the optical module of some embodiments of this application; Figure 4 This is a schematic diagram illustrating the pincushion distortion that occurs after light passes through a diffraction element in some embodiments of this application; Figure 5 This is a schematic diagram of light passing through a diffraction element and a modulation element in some embodiments of this application.

[0019] Explanation of icon numbers: 100. Optical module; 1. Diffraction element; 2. Housing; 21. Receiving cavity; 22. Opening; 23. Base plate; 24. Side panel; 3. Light source assembly; 31. Light source; 32. Refractive prism; 4. Adjustment element; 41. Fisheye lens; 42. Beam expander superlens; 5. Anti-reflective coating.

[0020] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] The technical solutions in this embodiment will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this embodiment are only used to explain the relative positional relationship and movement of each component in a specific posture (as shown in the attached figure). If the specific posture changes, the directional indicator will also change accordingly.

[0023] Furthermore, the use of terms such as "first," "second," etc., in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are feasible to those skilled in the art. If a combination of technical solutions contradicts each other or cannot be implemented, it should be considered that such a combination does not exist and is not within the scope of protection claimed in this application. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0026] The descriptions of directions such as "up", "down", "front", "back", "left", and "right" in this application are based on the directions shown in the figure and are only used to explain the relative positional relationship between the components in the posture shown in the figure. If the specific posture changes, the directional indication will also change accordingly.

[0027] With the continuous development of optical technology, structured light projectors play a crucial role in numerous application scenarios, such as 3D vision perception, structured light measurement, and LiDAR. Among these, 3D vision perception technology, as an important component of artificial intelligence and robotics, works by having a 3D recognition system project a special pattern of light spots onto a target object through the projector's optical module. The receiving device then uses the image of the target object to collect the distortion or deformation of the pattern on the object's surface to determine its three-dimensional shape. For areas not covered by the patterned light spots, relevant information cannot be directly obtained. Therefore, the angle at which the projector can project and the angle of the light source that the lens can receive determine the accuracy and completeness of the information obtained. For example, taking a robotic vacuum cleaner as an example, when 3D modeling the robot's path, the speckle pattern from a single projector may not completely cover the environment, leading to missing measurement data and affecting the safety of the path.

[0028] In view of this problem, the methods commonly used by those skilled in the art to increase the field of view include: 1. Using a single projector + a single lens module + a rotating scanning motor, the field of view is expanded by driving the single projector to rotate through the rotating scanning motor; 2. Using multiple projectors + multiple lens modules, the field of view is expanded by increasing the number of projectors and lens modules; 3. Using multiple projectors + single lens splicing to achieve FOV expansion, the field of view is increased by increasing the number of projectors.

[0029] The applicant found that while the aforementioned solutions could increase the field of view and obtain more complete information about the object's surface, they all increased the manufacturing cost of the 3D recognition system. In today's increasingly competitive market for robotic vacuum cleaners, this would undoubtedly significantly reduce the product's competitiveness. The applicant is considering whether it is possible to provide a technical solution that can expand the field of view without significantly increasing manufacturing costs.

[0030] After careful consideration, the applicant discovered that a diffraction element could be used. The diffracted light emitted from the light source would expand the field of view, eliminating the need for multiple projectors. However, the applicant was surprised to find that while the field of view increased after the light passed through the diffraction element, the image suffered severe distortion, significantly impacting measurement accuracy.

[0031] Therefore, this utility model provides an optical module.

[0032] Reference Figure 1According to some embodiments of this application, this application provides an optical module 100, including a housing 2, a light source assembly 3, a diffraction element 1, and an adjustment element 4. The housing 2 forms a receiving cavity 21 and an opening 22 communicating with the receiving cavity 21. The light source assembly 3 is disposed in the receiving cavity 21, and the diffraction element 1 is disposed in the receiving cavity 21. The light emitted by the light source assembly 3 is incident on the diffraction element 1. The adjustment element 4 is covered by the opening 22, and the adjustment element 4 is spaced apart from the diffraction element 1. The adjustment element 4 is used to reduce the distortion generated after the light passes through the diffraction element 1.

[0033] Figure 1 The light path emitted from the light source assembly 3 is shown by arrow A1. The optical module 100 of this application is a partial structural component of the projector. The housing 2 is the outer shell, enclosing a cavity 21 and an opening 22. Light is emitted from the opening 22 to the external environment. The light source assembly 3 refers to the component capable of emitting light. Light is emitted from the light source and incident on the diffraction element 1. The diffraction element 1 causes the light to diffract, thereby expanding the field of view. The adjustment element 4 is disposed at the opening 22, and can be threaded to the opening 22 or bonded to the outer edge of the opening 22. In this embodiment, the light path of the optical module 100 is as follows: light is emitted from the light source assembly 3, passes sequentially through the diffraction element 1 and the adjustment element 4, and is emitted from the adjustment element 4 into the external environment. The applicant, through careful study, discovered that although using the diffraction element 1 can expand the field of view, it causes severe distortion of the pattern transmitted from the light source assembly 3 onto environmental objects. The optical module 100 of this application is mainly used in 3D recognition systems. It determines the three-dimensional shape by observing the distortion or deformation of the pattern emitted by the light source component 3 on the surface of an environmental object. If the pattern itself has significant distortion, it will reduce the accuracy and reliability of the measurement of the environmental object. Even if image analysis methods are used for subsequent processing, it will greatly increase the processing difficulty.

[0034] To address this, the applicant adds an adjustment element 4 to the existing diffraction element 1. The adjustment element 4 adjusts the distortion produced by the diffraction element 1, specifically reducing the distortion. This ensures that the optical module 100 maintains a large field of view while minimizing the resulting distortion, thus improving the accuracy and reliability of environmental object measurements. This embodiment uses a combination of diffraction element 1 and adjustment element 4, replacing the multiple projectors used in related technologies, thereby reducing the manufacturing cost of the 3D recognition system.

[0035] In some embodiments, the diffraction element 1 can be a DOE (Diffractive Optical Element), MOE (Micro-Optical Element), or a diffuser sheet, and the material can be polycarbonate, polyethylene terephthalate, glass, or transparent aluminum oxide, etc. Alternatively, the diffraction element 1 can be packaged separately to achieve higher reliability. The optical module 100 can be connected using surface mount technology or designed as a flexible circuit board, allowing direct electrical connection via connectors during application. Regarding the specific transmission pattern of the optical module 100, the light source 31 can be designed as a zone-controllable emission aperture, and then the diffraction element 1 can be used to superimpose and replicate the pattern to form a pattern that meets the algorithm requirements.

[0036] Reference Figure 1 or Figure 2 In some embodiments, the adjustment element 4 includes a fisheye lens 41. Figure 2 The path of the light emitted from light source component 3 is shown by arrow A2. (Refer to...) Figure 4 , Figure 4 The image shows the pattern at a field of view of 105°. It can be seen that diffraction element 1 causes pincushion distortion in the light rays, and the degree of distortion is quite large. (Refer to...) Figure 5 , Figure 5 The pattern is formed by adding adjustment element 4 to diffraction element 1. The field of view is now larger at 140°, and the distortion is significantly reduced. This is because adjustment element 4 causes barrel distortion in the light, which can at least partially offset pincushion distortion, thus enabling adjustment element 4 to reduce the pincushion distortion produced by the light after passing through diffraction element 1.

[0037] As a specific embodiment of the adjustment element 4, the adjustment element 4 can be a fisheye lens 41. Here, the fisheye lens 41 uses an optical lens group with an infrared transmittance of over 98%. The fisheye lens 41 itself has a large field of view, and while achieving a large field of view, it also produces barrel distortion, which is combined with a diffraction element 1 with pincushion distortion. Those skilled in the art will understand that by superimposing the barrel distortion and pincushion distortion of the fisheye lens 41, the pincushion distortion can be at least partially offset, thus reducing the degree of pincushion distortion while maintaining a large field of view. It is also worth mentioning that using a diffraction element 1 with pincushion distortion in conjunction with the fisheye lens 41 can improve the photoelectric utilization rate, specifically, it can reach over 80%. Of course, multiple fisheye lenses 41 can also be used to form a lens group, which can further reduce distortion. In some specific embodiments, the fisheye lens 41 includes a first lens, a correction lens, and a second lens stacked together, with the first lens positioned close to the diffraction element 1.

[0038] Specifically, if the light source 31 of the light source assembly 3 is a chip, the size of the chip's light-emitting area is a*b, and the focal length of the diffraction element 1 is f, then according to the grating equation, we can obtain:

[0039]

[0040] The formulas for calculating the diffraction polar angle and diffraction azimuth angle at the exit point are:

[0041]

[0042] Where, d h d represents the minimum grating period in the transverse direction. v Let H*V represent the minimum grating period in the longitudinal direction. Then, the dimensions of the projected size H*V of diffraction element 1 are as follows:

[0043]

[0044] Where d is the projection distance, and d is less than or equal to the focal length f of the optical lens.

[0045] Reference Figure 3 In some embodiments, the adjustment element 4 includes a beam-expanding superlens 42, which is mounted in the opening 22. The beam-expanding superlens 42 includes a substrate and an array of nanostructures disposed on one side of the substrate. Figure 3The light path emitted from the light source assembly 3 is shown by arrow A3. As another specific embodiment of the adjustment element 4, the adjustment element 4 can employ a beam-expanding superlens 42. The beam-expanding superlens 42 is a subwavelength artificial nanostructure film that can modulate the incident light according to the nanostructure on the substrate, expanding the laser beam emitted from the diffraction element 1 to obtain amplified laser beams of various orders. The cross-sectional shape of the substrate is a regular hexagon and / or square and / or sector, with a nanostructure located at the center of each substrate, or at both the center and vertex of each substrate. The nanostructures are arranged in an array on the substrate, and each nanostructure contains an all-dielectric or plasma nanoantenna. The nanostructures can employ all-dielectric structural units, and the optional materials include, but are not limited to, titanium oxide, silicon nitride, fused silica, aluminum oxide, gallium nitride, gallium phosphide, and hydrogenated amorphous silicon. The distance between the beam-expanding superlens 42 and the diffraction element 1 is less than or equal to the focal length of the beam-expanding superlens 42. The nanostructure in the beam-expanding superlens 42 modulates the phase of the structured light emitted from the diffraction element 1 in accordance with the generalized Snell's law. As for the location of the nanostructure, it can be located on the side of the substrate facing away from the diffraction element 1; or, it can be located on the side of the substrate facing the diffraction element 1. Those skilled in the art can configure the nanostructure according to their specific needs.

[0046] Reference Figure 3 In some embodiments, the regulating element 4 further includes an antireflection film 5, which is disposed on the side of the substrate opposite to the nanostructure. The antireflection film 5 can improve light transmittance, thereby improving the utilization rate of light energy.

[0047] Reference Figure 2 or Figure 3 In some embodiments, the housing 2 includes a base plate 23 and a side panel 24 surrounding the base plate 23. The base plate 23 and the side panel 24 cooperate to form a receiving cavity 21, and a light-shielding layer is coated on the side panel 24. The side panel 24 can be an annular, circular, or square panel. One side of the side panel 24 cooperates with the base plate 23 to form the receiving cavity 21. An opening 22 is formed on the side of the side panel 24 away from the base plate 23, and the opening 22 communicates with the receiving cavity 21. The light-shielding layer on the side panel 24 is mainly to prevent light from leaking out of the side panel 24. Specifically, the light-shielding layer can be disposed on the side of the side panel 24 facing the receiving cavity 21 or on the side away from the receiving cavity 21. The light-shielding layer can also have a reflective film that reflects light, so that the light is reflected and emitted again from the adjustment element 4, reducing light energy loss and improving light energy utilization. In some specific embodiments, the base plate 23 can be a printed circuit board, a copper substrate, an aluminum substrate, or a resin substrate.

[0048] In some embodiments, the light source assembly 3 includes a light source 31 and a refractive prism 32. The light source 31 is disposed on the side 24, and the diffraction element 1 is disposed on the light emission path from the light source to the refractive prism 32. The light emitted by the light source 31 is diffracted by the diffraction element 1, and then refracted by the refractive prism 32 before being incident on the adjustment element 4.

[0049] Reference Figure 1 In some specific embodiments, the light source assembly 3 may include only one light source 31. In this case, the light source 31 is disposed on the base plate 23, and the diffraction element 1 and the adjustment element 4 are disposed in parallel and spaced apart. The diffraction element 1 is disposed on the side of the adjustment element 4 facing the receiving cavity 21. At this time, the light source 31 is disposed directly opposite the diffraction element 1, and the light emitted from the light source 31 enters the adjustment element 4 after being diffracted by the diffraction element 1.

[0050] Reference Figure 2 or Figure 3 In some specific embodiments, the light source assembly 3 may include a light source 31 and a refractive prism 32, which refracts incident light. Specifically, the refractive prism 32 is an isosceles triangular prism, which includes two right-angled sides and a hypotenuse. The light source 31 is positioned towards one of the right-angled sides, and the other right-angled side is positioned towards the diffraction element 1. In this case, the light source 31 is not positioned on the base plate 23, but may be positioned on the side 24 or on a seat within the receiving cavity 21. The light source 31 emits light towards one of the right-angled sides, and the light passes perpendicularly through the right-angled side and is incident on the hypotenuse. The hypotenuse is actually a reflective surface, reflecting the light so that it is incident perpendicularly to the other right-angled side and then towards the adjustment element 4. This embodiment can increase the distance that the light rays emitted from the diffraction element 1 travel to the optical center of the adjustment element 4, that is, it can increase the focal length. With a fixed focal length, the distance between the diffraction element 1 and the adjustment element 4 can be reduced, thereby reducing the volume of the optical module 100. Specifically, the light source 31 can be a light-emitting diode, a vertical laser, or a side-emitting laser, and can be individually semiconductor packaged to achieve higher reliability.

[0051] In some embodiments, a mounting base is provided on the base plate 23, and a first slide rail and a second slide rail are provided on the mounting base. The refractive prism 32 is slidably mounted on the first slide rail, and the diffraction element 1 is slidably mounted on the second slide rail. The refractive prism 32 can be slidably connected to the first slide rail so that the refractive prism 32 can slide on the first slide rail, and the diffraction element 1 is slidably mounted on the second slide rail so that the diffraction element 1 can move on the second slide rail. Thus, the positions of the refractive prism 32 and the diffraction element 1 can be adjusted separately to adapt to different application scenarios. Specifically, the direction of movement can be along... Figure 2The first direction indicated by the middle arrow X can also be the second direction indicated by the arrow Y, or a third direction perpendicular to both the first and second directions, that is, perpendicular to the direction along... Figure 2 The orientation of the paper.

[0052] According to some embodiments of this application, this application provides a 3D recognition system, including a projection module, an image acquisition module, and a three-dimensional reconstruction module. The projection module includes the aforementioned optical module 100. The projection module is used to emit light to the surrounding environment through the optical module 100. The image acquisition module is used to acquire depth image information of the surrounding environment. The three-dimensional reconstruction module is used to reconstruct the depth image information to obtain a three-dimensional model of the environment.

[0053] The projection module here is also known as the projector. The projector emits light into the surrounding environment through its internal optical module. The emitted light, when transmitted onto an object, forms a pattern. The image acquisition module can acquire the pattern from the object's surface. Since the object itself may be three-dimensional, the pattern information includes depth image information, which can reflect the distortion or deformation of the pattern. The image depth information is sent to the 3D reconstruction module, which can reconstruct the depth image information to obtain a 3D model of the object, which is also a 3D model of the environment. This allows for the recognition of objects in the environment, and it is a 3D recognition method. Of course, the 3D recognition system may also include a processor and a memory. Since the 3D recognition system includes all the technical solutions of all embodiments of the optical module 100 described above, it possesses at least all the beneficial effects brought by the above-mentioned technical solutions, which will not be elaborated further here.

[0054] According to some embodiments of this application, this application provides a robotic vacuum cleaner, which includes the aforementioned 3D recognition system and a path planning module. The path planning module is used to generate a movement path based on a 3D environmental model. The robotic vacuum cleaner can obtain a 3D model of an object based on the acquired image depth information. The path planning module rationally plans the robotic vacuum cleaner's movement path, reducing the possibility of collisions with objects. Specifically, the robotic vacuum cleaner's workflow includes: first, acquiring an RGB image and image depth information of the target object; then, performing feature extraction and feature fusion on the RGB image and image depth information respectively; and then reconstructing the depth image to obtain a 3D model of the target object. Here, an RGB image is an image pattern that mixes various colors using different intensities of red, green, and blue primary colors of light. A projection module projects a structured light pattern into the surrounding environment during movement; an infrared camera in the image acquisition module acquires reflected structured light data, and a visible light camera simultaneously acquires visible light data; a depth image is generated based on the structured light data; an RGB image is generated based on the visible light data; and the depth image and the RGB image are converted to the same coordinate system. The 3D reconstruction module extracts features from the depth image to obtain a depth feature map; extracts features from the RGB image to obtain an RGB feature map; fuses the depth feature map and the RGB feature map at multiple scales to obtain a fused feature map of multiple sizes; performs graph convolution processing on the fused feature map of multiple sizes to obtain a 3D graphic; and constructs a 3D model of the target object based on the 3D image.

[0055] The above description is merely an optional embodiment of this application and does not limit the scope of protection of this application. Any equivalent structural transformations made based on the content of this application's specification and drawings under the concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of this application.

Claims

1. An optical module, characterized in that, include: A housing having a receiving cavity and an opening communicating with the receiving cavity; A light source assembly, wherein the light source assembly is disposed within the receiving cavity; A diffraction element is disposed within the receiving cavity, and light emitted from the light source assembly is incident on the diffraction element; An adjustment element is provided, which covers the opening and is spaced apart from the diffraction element. The adjustment element is used to reduce the distortion of light after it passes through the diffraction element.

2. The optical module according to claim 1, characterized in that, The adjustment element includes a fisheye lens, the diffraction element causes the light to produce pincushion distortion, and the adjustment element can cause the light to produce barrel distortion, so that the adjustment element can reduce the pincushion distortion produced by the light after passing through the diffraction element.

3. The optical module according to claim 2, characterized in that, The fisheye lens includes a first lens, a correction lens, and a second lens stacked together, with the first lens positioned close to the diffraction element.

4. The optical module according to claim 1, characterized in that, The adjustment element includes a beam-expanding superlens mounted on the opening. The beam-expanding superlens includes a substrate and an array of nanostructures disposed on one side of the substrate.

5. The optical module according to claim 4, characterized in that, The nanostructure is disposed on the side of the substrate away from the diffraction element; or, the nanostructure is disposed on the side of the substrate facing the diffraction element.

6. The optical module according to claim 4, characterized in that, The regulating element further includes an antireflection film disposed on the side of the substrate opposite to the nanostructure.

7. The optical module according to claim 1, characterized in that, The housing includes a bottom plate and a side enclosure surrounding the bottom plate. The bottom plate and the side enclosure cooperate to form the receiving cavity. The side enclosure is coated with a light-shielding layer.

8. The optical module according to claim 7, characterized in that, The light source assembly includes a light source and a refractive prism. The light source is disposed on the side enclosure, and the diffraction element is disposed on the light emission path from the light source to the refractive prism. The light emitted by the light source is diffracted by the diffraction element, and then refracted by the refractive prism before entering the adjustment element.

9. The optical module according to claim 8, characterized in that, The base plate is provided with a mounting base, and the mounting base is provided with a first slide rail and a second slide rail. The refractive prism is slidably mounted on the first slide rail, and the diffraction element is slidably mounted on the second slide rail.

10. A 3D recognition system, characterized in that, The system includes a projection module, an image acquisition module, and a 3D reconstruction module. The projection module includes an optical module as described in any one of claims 1 to 9. The projection module is used to emit light to the surrounding environment through the optical module. The image acquisition module is used to acquire depth image information of the surrounding environment. The 3D reconstruction module is used to reconstruct the depth image information to obtain a 3D model of the environment.

11. A sweeping robot, characterized in that, The robotic vacuum cleaner includes the 3D recognition system of claim 10, and further includes a path planning module, which is used to generate a movement path based on the three-dimensional environmental model.

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