Light projector for depth camera and depth camera
By incorporating scattering and light-blocking structures into the light projector of the depth camera, the problem of overexposure in close-range imaging was solved, achieving accuracy and comprehensiveness in both long-range and close-range imaging, and ensuring the precision of depth measurement.
Patent Information
- Application Number
- CN202610048075.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-14
- Publication Date
- 2026-02-17
AI Technical Summary
When depth cameras perform long-distance and close-range imaging, close-range imaging is prone to overexposure, which affects the accuracy of depth measurement.
Design a light projector for a depth camera, employing a scattering structure and a light-blocking structure on the projection lens. The scattering structure includes a non-uniformly distributed scattering region for scattering structured light, and the light-blocking structure is used to reduce the transmittance of the scattering region to adjust the distribution of light.
While preventing overexposure in close-range imaging, the output power of the light projector is kept undiminished, ensuring the accuracy and comprehensiveness of depth measurements and improving the density of calculated depth information.
Smart Images
Figure CN121541405A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of depth measurement technology, and more particularly to a light projector for a depth camera and a depth camera. Background Technology
[0002] A depth camera is a special camera that can acquire information about the distance between objects in a scene and the camera. It measures the depth value of each pixel to form a depth map. This technology is widely used in computer vision, robotics, augmented reality, virtual reality, 3D scanning, and other fields.
[0003] The mainstream methods for measuring depth values using depth cameras include Time-of-Flight (ToF), structured light, and binocular stereo vision algorithms. Both ToF and structured light algorithms require a light projector to emit light pulses into the target space, and the depth value of the object in the target space is obtained by measuring and analyzing the reflected light received by the light receiver. To improve the effective range and sharpness of long-distance imaging, it is usually necessary to maintain the output power of the light projector at a certain level. However, for closer targets, close-range imaging can lead to overexposure. Summary of the Invention
[0004] This application provides a light projector and a depth camera for a depth camera, in order to improve the technical problem of overexposure in close-range imaging when the light projector has a wide measurement range.
[0005] For the purposes mentioned above, this application provides the following technical solution: The first aspect of this application provides a light projector for a depth camera, comprising: A laser is used to project the first structured light. A projection lens is used to adjust the propagation path of the first structured light to obtain the second structured light and floodlight; The projection lens is provided with a scattering structure, which is a pattern on the projection lens for scattering structured light. The scattering structure includes multiple scattering regions, which are non-uniformly distributed on the projection lens. The length of each scattering region in at least one direction is less than the length of the corresponding structured light spot in that direction. The corresponding structured light spot is the structured light spot that passes through the scattering region.
[0006] Furthermore, the projection lens includes at least one of conventional optical lens devices, diffractive optical devices, and metasurface optical devices.
[0007] Furthermore, the projection lens has a scattering structure on the outermost device in the direction of propagation of the structured light spot.
[0008] Furthermore, the area ratio of the scattering region in the first region is greater than or equal to the area ratio of the scattering region in the second region; In the working state, the first region is closer to the ground in the vertical direction than the second region.
[0009] Furthermore, the shape of the scattering region includes at least one of circular, elliptical, and linear shapes.
[0010] Furthermore, the area of the scattering region accounts for less than or equal to 95% of the area of the corresponding structured light spot.
[0011] Furthermore, each of the scattering regions includes multiple laser engraving points. The number of laser engraving points contained in scattering regions of different areas is different. The larger the area of the scattering region, the more laser engraving points it contains.
[0012] Furthermore, the light projector for the depth camera further includes: A light-shielding structure is used to reduce the light transmittance of the area corresponding to the scattering structure and the light-shielding structure.
[0013] A second aspect of this application provides a depth camera, comprising: A light projector for emitting structured light spots toward a target space, the light projector having the structure of a light projector for a depth camera as described in the first aspect; A light receiver is used to receive reflected light from objects in the target space. The processing circuit calculates the depth information of the object in the target space based on the structured light algorithm and the time-of-flight (ToF) algorithm, respectively.
[0014] This application possesses at least the following advantages or beneficial effects: This embodiment, by designing a light projector and a depth camera for a depth camera, solves the technical problem of overexposure during close-range imaging when the light projector simultaneously performs long-range and close-range imaging. It achieves the technical effect of preventing overexposure during close-range imaging without causing power loss in the light projector's output, thus ensuring the accuracy of depth measurement. Furthermore, it allows the area between structured light spots to be illuminated, filling in previously unilluminated areas and providing more comprehensive illumination of the object. This results in a more comprehensive signal received by the light receiver, especially when using the ToF algorithm to calculate depth information, leading to a higher density of the final calculated depth values. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0016] Figure 1A This is a schematic diagram of the structure of a light projector for a depth camera provided in Embodiment 1 of this application; Figure 1B This is a schematic diagram of the structure of a laser; Figure 1C for Figure 1B Enlarged view of region A in the middle; Figure 1D An exploded view of a light projector used in a depth camera; Figure 2A This is a schematic diagram of a light projector, where the projection lens is a conventional optical lens device. Figure 2B This is a schematic diagram of a light projector, where the projection lens is a type of diffractive optical device. Figure 2C This is a texture map of the DOE surface; Figure 2D This is a schematic diagram of a light projector, which is a type of metasurface optical device. Figure 2E This is a texture map of the surface of a metasurface optical device; Figure 3A This is a schematic diagram of a projection lens; Figure 3B for Figure 3A Enlarged view of region B in the middle; Figure 4A This is a schematic diagram of a structured light method; Figure 4B-4C This is a schematic diagram of the structured light spot and the scattering region; Figure 5A This is a schematic diagram of structured light passing through the scattering region; Figure 5B This is a schematic diagram of structured light passing through a scattering structure. Figure 5C This is a schematic diagram of the light projector described in this application projecting structured light; Figure 6A A schematic diagram showing the distribution of the scattering area on a projection lens; Figure 6B A physical diagram showing the distribution of the scattering area on a projection lens; Figure 7 for Figure 6BMagnified image of the medium scattering region Figure 8 This is a schematic diagram of a light-shielding structure; Figure 9 This is a schematic diagram of a depth camera; Reference numerals: 1-Light projector; 11-Projection lens; 12-Laser; 111, 112-Texture; 121-Light-emitting unit; 14-Scattering structure; 141-Scattering area; 2-Optical receiver; 3-Processing circuit; 4-Laser engraving of dots; 5-First structured light; 52-Second structured light and floodlight; 51-Structured light spot. Detailed Implementation
[0017] The technical solutions of this application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0018] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0019] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0020] Furthermore, terms such as "horizontal" and "vertical" do not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be completely horizontal, but can be slightly tilted. Similarly, terms such as "front," "back," "left," and "right" do not imply that the component must be absolutely front, back, left, or right, but can be slightly tilted.
[0021] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0022] Example 1 The light projector for a depth camera provided in this application can balance the brightness values required for close-range and long-range imaging, ensuring the effective distance and clarity of long-range imaging while preventing overexposure in close-range imaging.
[0023] Figure 1A This is a schematic diagram of a light projector for a depth camera provided in Embodiment 1 of this application. Figure 1B This is a schematic diagram of the structure of a laser. Figure 1C for Figure 1B Enlarged view of region A in the middle. Figure 1D This is an exploded view of a light projector used in depth cameras. Figure 1A-1D As shown, the light projector 1 includes a projection lens 11 and a laser 12, the laser 12 being used to project the first structured light 5. The laser 12 includes multiple light-emitting units 121. Figure 1B and Figure 1C The number and arrangement of the light-emitting units 121 are merely exemplary and do not imply that the number and arrangement of the light-emitting units 121 of the laser 12 in this embodiment can only be [specific examples]. Figure 1B and Figure 1C The state shown is as follows. The number and arrangement of the light-emitting units 121 of the laser 12 need to match the projection lens 11. When the number of light-emitting units 121 of the laser 12 is 200, the first structured light 5 projected includes 200 structured light spots, which are further processed to form a second structured light for depth measurement.
[0024] like Figure 1D As shown, the light projector 1 also includes a projection lens 11, which is used to adjust the propagation path of the first structured light 5 to obtain the second structured light and floodlight. Figure 1D The projection lens 11 shown is an integrated structure that includes one or more optical components. In this application, since the floodlight can provide background light for the second structured light, the floodlight is also referred to directly as background light in some parts of this application.
[0025] Optionally, the projection lens 11 includes at least one of conventional optical lens devices, diffractive optical devices, and metasurface optical devices. Figure 2A The projection lens is a schematic diagram of a light projector, which is a conventional optical lens device. The projection lens 11 includes three lenses. The propagation path of the first structured light 5 is adjusted by the projection lens 11 to obtain the second structured light and the floodlight 52. The number of structured light spots of the second structured light and the floodlight 52 is the same as the number of structured light spots of the first structured light 5.
[0026] Figure 2B This is a schematic diagram of a light projector, specifically a projection lens, which is a type of diffractive optical element (DOE). The projection lens 11 includes a diffractive optical element (DOE), and the texture 111 of the DOE surface is as follows: Figure 2C As shown, the projection lens 11 can be located on the outer or inner surface of the DOE lens to adjust the propagation path of the first structured light 5, thereby obtaining the second structured light and floodlight 52. The number of structured light spots of the second structured light and floodlight 52 is greater than the number of structured light spots of the first structured light 5.
[0027] Figure 2D This is a schematic diagram of a light projector using a projection lens, which is a type of metasurface optical device. The projection lens 11 includes a metasurface optical device (Metalens), and the surface texture 112 of the metasurface optical device is as follows: Figure 2E As shown, the projection lens 11 can be located on the outer or inner surface of the metasurface optical device lens. By adjusting the propagation path of the first structured light 5 through the projection lens 11, a second structured light and a floodlight 52 are obtained. The number of structured light spots in the second structured light and the floodlight 52 is equal to the number of structured light spots in the first structured light 5. It is understood that the projection lens can include two or more of conventional optical lens devices, diffractive optical devices, and metasurface optical devices. The specific application depends on actual needs, and it may further include auxiliary structures such as a support.
[0028] like Figure 3A As shown, a scattering structure 14 is provided on the projection lens 11. The scattering structure 14 is a pattern provided on the projection lens 11 for scattering structured light. The scattering structure 14 includes multiple scattering regions 141. The scattering regions 141 are non-uniformly distributed on the projection lens 11, and the length of the scattering region 141 in at least one direction is less than the length of the corresponding structured light spot in that direction. The corresponding structured light spot is the structured light spot 51 that passes through the scattering region 141.
[0029] Figure 3B for Figure 3A A magnified view of region B in the middle; for the sake of image simplicity, Figure 3B Only the scattering structure 14 is shown; other structures on the projection lens 11 are omitted. (For example...) Figure 3BAs shown, the scattering structure 14 includes multiple scattering regions 141, in Figure 3B In the projection lens 11, each scattering region 141 is the same size and shape, but from the perspective of the entire projection lens 11, the scattering regions 141 are non-uniformly distributed on the projection lens 11. Only a non-uniform structure can cause the structured light passing through different regions of the projection lens 11 to be scattered to different degrees, so that the depth camera can balance the brightness values required for close-range imaging and long-range imaging.
[0030] Figure 4A This is a schematic diagram of a structured light. There are many types of structured light, such as speckle structured light or stripe structured light. Figure 4A It is a speckle structured light, which includes a large number of irregularly distributed structured light spots. The distribution of the structured light spots is relatively uniform but irregular. Figure 4B-4C This is a schematic diagram of the structured light spot and the scattering region. The diameter of the structured light spot is typically between 0.5 mm and 3 mm. Therefore, when the diameter of the scattering region 141 is smaller than the diameter of the structured light spot 51, the diameter of the scattering region 141 is typically less than 3 mm. Figures 4B-4C As shown, the length of the scattering region 141 in at least one direction is less than the length of the corresponding structured light spot 51 in that direction. The corresponding structured light spot 51 is the structured light spot that passes through the scattering region 141. In this application, the terms "structured light spot" and "speckle" are used interchangeably.
[0031] Optionally, the shape of the scattering region 141 includes at least one of circular, elliptical, and linear shapes. For example... Figure 4B As shown, the scattering region 141 is circular, and its diameter is smaller than that of the structured light spot 51. That is, the length of the scattering region 141 in all directions is smaller than the length of the corresponding structured light spot 51 in that direction. Figure 4C As shown, the scattering region 141 is elliptical, and the minor axis of the scattering region 141 is smaller than the diameter of the structured light spot 51. That is, the length of the scattering region 141 in the X direction is smaller than the length of the corresponding structured light spot 51 in that direction. Figure 4CFor illustrative purposes, the scattering region 141 in the figure may not be a standard ellipse due to drawing or other reasons. The shape of the scattering region 141 can also be rectangular, linear, or other shapes, or even irregular, as long as the length of the scattering region 141 in at least one direction is less than the length of the corresponding structured light spot 51 in that direction. Setting the scattering region 141 as circular or elliptical simplifies the manufacturing process. Currently, the process for manufacturing the scattering region 141 is usually laser etching, and the scattering region obtained by laser etching is usually circular or approximately circular. Therefore, setting the scattering region 141 as circular or elliptical is more compatible with the laser etching process and reduces production costs.
[0032] Figure 5A This is a schematic diagram of structured light passing through scattering regions. As shown, two scattering regions 141 are schematically depicted; however, the actual number of scattering regions 141 may be more than two. As illustrated, structured light passing through scattering regions 141 is scattered, and its propagation direction changes, while the propagation direction of structured light passing through non-scattering regions remains unchanged. Figure 4B As shown, since the length of the scattering region 141 in at least one direction is less than the length of the corresponding structured light spot 51 in that direction, when the beam forming a single structured light spot passes through the projection lens 11, the light illuminating the scattering region 141 is scattered at a small angle to form background light, while the remaining light passes through to form the structured light spot. Figure 5B This is a schematic diagram of structured light passing through a scattering structure, as shown in the figure. The structured light spot at the top corresponds to... Figure 3B The upper and middle regions do not include the scattering structure 14, while Figure 5B The structured light spot below corresponds to the scattering structure 14. Therefore, by setting a scattering structure on the projection lens 11, it is possible to simultaneously obtain a high-contrast structured light spot pattern and a low-contrast structured light spot pattern consisting of a structured light spot and a background light.
[0033] Figure 5CThis is a schematic diagram of the structured light projector described in this application. The light projector is an essential component of a depth camera. It projects structured light into the target space, allowing the camera to determine the object's position based on reflected light. When the depth camera is placed low, such as as a component of a robotic vacuum cleaner, the ground occupies a large portion of the structured light image projected by the camera. Due to the large number and concentrated spatial position of the structured light spots projected onto the ground, the reflected light received by the depth camera from the ground is usually brighter, making the intensity of reflected light from the ground significantly greater than that from distant locations. By incorporating a scattering structure on the light projector, the brightness of the structured light spots emitted to the ground is reduced, and the floodlight, acting as background light, is enhanced, preventing excessively strong reflected light signals from the ground from affecting the algorithm's calculation of the depth information of objects in the target space. Figure 5C The angle shown is illustrative. The boundary between high-contrast and low-contrast structured light spot patterns is usually selected adaptively according to the application scenario of the depth camera. Alternatively, a gradual transition can be used to set the connection between high-contrast and low-contrast structured light spot patterns. The closer to the ground, the lower the contrast, that is, the proportion of structured light spot and background light gradually changes.
[0034] Optionally, the area ratio of the scattering region 141 in the first region is greater than or equal to the area ratio of the scattering region 141 in the second region; wherein, in the working state, the first region is closer to the ground than the second region.
[0035] Figure 6A This is a schematic diagram of the distribution of the scattering area on a projection lens. Figure 6B This is a physical diagram showing the distribution of scattering areas on a projection lens. As shown, the first region C and the second region D are circular regions of the same area. Because the surface of the projection lens perpendicular to the direction of structured light propagation is set perpendicular or nearly perpendicular to the ground in the working state, and to prevent the structured light near the ground from being too bright, the structured light needs to be scattered more fully at positions closer to the ground along the vertical direction. Figure 6A As shown, the first region C is closer to the ground vertically than the second region D. Therefore, the area of the scattering region 141 in the first region C is larger than that in the second region D, resulting in greater scattering. This leads to lower contrast in the structured light spot near the ground and brighter background light. The shapes of the first region C and the second region D are not specified here; the key point is that the closer to the ground, the larger the area of the scattering region 141, and the larger its area proportion, resulting in a stronger scattering effect. This design takes into account the scenario where the light projector is applied to the depth camera in the robotic vacuum cleaner, where the robot is relatively close to the ground. Figure 5CAs shown, the closer the angle is to the ground, the denser the structured light spot becomes, and the more likely it is to cause excessive brightness. Therefore, it is necessary to gradually increase the background light to reduce the brightness of the structured light spot, thereby improving the matching degree between the reflected light of objects in the target space and the algorithm required for calculating the depth.
[0036] Optionally, the area of the scattering region 141 is less than or equal to 95% of the area of the corresponding structured light spot. The scattering region 141 described in this embodiment scatters light rays incident on it at a small angle. Even with a large area of scattering region 141, it can still ensure that the structured light spot is not completely covered by the background light. Therefore, as long as the area of the scattering region 141 is less than or equal to 95% of the area of the corresponding structured light spot, the computational requirements for depth information by the structured light algorithm can be guaranteed. If the area ratio of the structured light spot further increases, exceeding 95%, the brightness of the structured light spot becomes too low, and the background light becomes too strong, making it difficult to meet the requirements of the structured light algorithm. Choosing an appropriate area ratio for the scattering region 141 ensures that the brightness of the nearby structured light spot is moderate and that there is a suitable background light.
[0037] Optionally, each of the scattering regions 141 includes a plurality of laser-etched points 142. The number of laser-etched points 142 contained in scattering regions 141 of different areas is different. The larger the area of the scattering region 141, the more laser-etched points 142 it contains.
[0038] Figure 7 for Figure 6B A magnified image of the mid-scattering region. (e.g.) Figure 7As shown, each scattering region 141 includes multiple laser-etched points 4, which together form a circular scattering region 141. Laser etching is a technique that uses a high-energy-density laser beam to locally process the surface of a material. It does not require physical contact with the material, avoids mechanical stress contamination, and has advantages such as high precision and wide material applicability. By adjusting the diameter of the focused spot of the laser, the diameter of each laser-etched point 4 can be adjusted. In this embodiment, the diameter of the laser-etched point 4 is adjusted to be smaller, so that each scattering region 141 includes multiple laser-etched points 4, alleviating the problem of uneven scattering angle caused by a single laser-etched point 4. Specifically, due to the "crater"-shaped surface of a single laser-etched point 4, the radius of curvature at the center and the edge of the "crater" differs greatly, resulting in a large difference in the scattering angle of light, which leads to uneven scattering angle of structured light in the scattering region 141. By setting multiple laser-etched points 4 in each scattering region 141, the scattering angle of structured light in the scattering region 141 is made more uniform, and the scattering effect is better. The number of laser-etched points 4 included in a single scattering region 141 can be selected according to specific circumstances. For example, a larger scattering region 141 can contain more laser-etched points 4, and a scattering region 141 with higher requirements for scattering angle uniformity can contain more laser-etched points 4, etc. It is understood that when using laser etching, the surface of the scattering region may have slight depressions, but when using other processes such as coating optical materials, the scattering region may not have obvious hole-like depressions.
[0039] Optionally, the projection lens 11 has a scattering structure 14 on the outermost device in the direction of propagation of the structured light spot. For example... Figure 2A As shown, when the projection lens 11 includes conventional optical lens components, a scattering structure 14 can be provided on the S1 or S2 surface of the projection lens 11. Specifically, a laser etching process can be used to etch the scattering area on the lens surface. Figure 2B As shown, when the projection lens 11 includes diffractive optical elements, a scattering structure 14 can be provided on the S3 surface of the projection lens 11, which has no texture 111. For example... Figure 2D As shown, when the projection lens 11 includes metasurface optics, a scattering structure 14 can be provided on the S4 surface of the projection lens 11 without texture 112. The advantage of this arrangement is that placing the scattering structure on the outermost optics simplifies the design and prevents the scattered background light and structured light spots from being processed again by other optics, generating stray light and affecting subsequent depth value calculations.
[0040] This embodiment addresses the technical problem of overexposure during close-range imaging when the light projector simultaneously performs long-range and close-range imaging. It achieves the goal of preventing overexposure during close-range imaging without sacrificing the light projector's output power, thus ensuring the accuracy of depth measurements. Furthermore, it allows light to illuminate areas between structured light spots, filling in previously unilluminated areas and providing more comprehensive illumination of the object. This results in a more complete signal received by the light receiver, leading to a higher density of depth values, particularly when using the Time-of-Flight (ToF) algorithm to calculate depth information.
[0041] This application achieves the goal of ensuring a clear projected structured light spot while allocating a portion of the energy to form floodlight illumination. The projected structured light spot can be used to generate a depth map with accurate dimensions, while the floodlight can be used to supplement details. Simultaneously, by adjusting the scattering degree in different areas, the light spot energy of different fields of view can be modulated, ensuring sufficient brightness of the structured light spot at a distance while preventing overexposure at close range.
[0042] Example 2 The difference between this embodiment and the light projector for a depth camera in Embodiment 1 is that it also includes a light-shielding structure, which is used to reduce the light transmittance of the area corresponding to the light projector and the light-shielding structure.
[0043] Considering that even with a high output power from the light projector, the near-field structured light spot still exhibits excessive brightness after scattering—for example, even after all the near-field structured light spots have been scattered into background light, the background light brightness remains too high—it is necessary to further reduce the brightness of the near-field structured light spot or background light. To further reduce brightness, a light-shielding structure can be incorporated into the light projector to attenuate light energy. For instance, a frosted finish or light-absorbing material can be applied to the vertical position of the projection lens 11 near the ground, as described in Embodiment 1, to serve as a light-shielding structure. This light-shielding structure absorbs light to a certain extent, thereby further reducing the brightness of the structured light spot and background light projected near the ground in the vertical direction.
[0044] Figure 8 This is a schematic diagram of a light-shielding structure, which can overlap with the scattering structure. Figure 8 As shown, the light transmittance of the shading structure is the same in the horizontal direction and varies unidirectionally in the vertical direction. The light transmittance is lower the closer it is to the ground, and it gradually decreases from 90% to 50%. Figure 8The light transmittance of the light-shielding structure given is gradually changing. In practical applications, the light transmittance of different positions of the light-shielding structure can be designed according to specific needs. For example, the area of the light-shielding structure can be designed to be smaller than the surface area of the projection lens, the light-shielding structure can be set to uniform light transmittance, and it can only exist in the area near the ground when the light projector is in operation.
[0045] This embodiment designs a light projector for a depth camera that includes a light-shielding structure. This solves the problem that a light projector with only a scattering structure cannot completely solve the problem of overexposure in close-range imaging. The light projector further attenuates the structured light spot and background light near the ground in the vertical direction, preventing overexposure in close-range imaging of the depth camera and improving the accuracy of depth measurement.
[0046] Example 3 Figure 9 This is a schematic diagram of a depth camera. As shown, the depth camera mainly includes a light projector 1, a light receiver 2, and a processing circuit 3. The light projector 1 is used to emit light into the target space, such as... Figure 5B The structured light spot shown is described in the example. The light projector 1 has the structure of a light projector for a depth camera as described in Example 1 or Example 2.
[0047] The depth camera also includes a light receiver 2 and a processing circuit 3. The light receiver 2 is used to receive reflected light from objects in the target space. The processing circuit 3 calculates the depth information of the objects in the target space according to the structured light algorithm and the time-of-flight (ToF) algorithm, respectively. Since the depth camera described in this embodiment supports both the structured light algorithm and the ToF algorithm, it is necessary to ensure the recognizability of the structured light spot at close range while preventing overexposure at near distances. Using the light projector described in this application enables the depth camera to ensure the effective distance and clarity of long-distance imaging while preventing overexposure at close ranges, without causing loss of output power of the light projector, maintaining the shape of the emitted light spot, and ensuring the accuracy of depth measurement.
[0048] The depth camera in this embodiment fully leverages the performance advantages of the light projector described in Embodiment 1, thus achieving the same technical effect as the light projector for the depth camera described in Embodiment 1. That is, it achieves the technical effect of ensuring the effective distance and clarity of long-distance imaging while preventing overexposure in close-distance imaging, without causing loss of output power of the light projector, maintaining the shape of the emitted light spot, and ensuring the accuracy of depth value measurement.
[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A light projector for a depth camera, the light projector comprising: The application relates to a light projector for a depth camera, comprising: a laser (12) for projecting first structured light (5); a projection lens (11) for adjusting the propagation path of the first structured light (5) to obtain second structured light and flood light (52); wherein the projection lens (11) is provided with a scattering structure (14), the scattering structure (14) is a pattern arranged on the projection lens (11) and used for scattering structured light, the scattering structure (14) comprises a plurality of scattering areas (141), the scattering areas (141) are non-uniformly distributed on the projection lens (11), and the length value of the scattering areas (141) in at least one direction is smaller than the length value of a corresponding structured light spot in the direction; the corresponding structured light spot is a structured light spot (51) passing through the scattering area (141). The projection lens (11) comprises at least one of a conventional optical lens device, a diffractive optical device and a metasurface optical device. The scattering structure (14) is arranged on the outermost device of the structured light spot in the propagation direction. The area proportion of the scattering areas (141) in a first area is greater than or equal to the area proportion of the scattering areas (141) in a second area; 2. The light projector for a depth camera of claim 1, wherein, In the working state, the first area is closer to the ground in the vertical direction than the second area.
3. The light projector for a depth camera of claim 2, wherein, The shape of the scattering areas (141) comprises at least one of a circle, an ellipse and a line.
4. The light projector for a depth camera of claim 1, wherein, The area proportion of the scattering areas to the area of the corresponding structured light spot is less than or equal to 95%. Each scattering area (141) comprises a plurality of laser engraving etching points (142), the number of the laser engraving etching points (142) contained by the scattering areas (141) with different areas is different, and the larger the area of the scattering area (141) is, the more the laser engraving etching points (142) contained by the scattering area (141) are.
5. The light projector for a depth camera of claim 4, wherein, Further comprising: a light-shielding structure for reducing the light transmittance of the scattering structure (14) in a region corresponding to the light-shielding structure.
6. The light projector for a depth camera of claim 5, wherein, The application relates to a light projector for a depth camera, comprising: a laser (12) for projecting first structured light (5); a projection lens (11) for adjusting the propagation path of the first structured light (5) to obtain second structured light and flood light (52); wherein the projection lens (11) is provided with a scattering structure (14), the scattering structure (14) is a pattern arranged on the projection lens (11) and used for scattering structured light, the scattering structure (14) comprises a plurality of scattering areas (141), the scattering areas (141) are non-uniformly distributed on the projection lens (11), and the length value of the scattering areas (141) in at least one direction is smaller than the length value of a corresponding structured light spot in the direction; the corresponding structured light spot is a structured light spot (51) passing through the scattering area (141).
7. The light projector for a depth camera of claim 6, wherein, The projection lens (11) comprises at least one of a conventional optical lens device, a diffractive optical device and a metasurface optical device.
8. The light projector for a depth camera of claim 1, wherein, The scattering structure (14) is arranged on the outermost device of the structured light spot in the propagation direction. The area proportion of the scattering areas (141) in a first area is greater than or equal to the area proportion of the scattering areas (141) in a second area; 9. A depth camera, characterized by In the working state, the first area is closer to the ground in the vertical direction than the second area. The shape of the scattering areas (141) comprises at least one of a circle, an ellipse and a line. The area proportion of the scattering areas to the area of the corresponding structured light spot is less than or equal to 95%. Each scattering area (141) comprises a plurality of laser engraving etching points (142), the number of the laser engraving etching points (142) contained by the scattering areas (141) with different areas is different, and the larger the area of the scattering area (141) is, the more the laser engraving etching points (142) contained by the scattering area (141) are. Further comprising: a light-shielding structure for reducing the light transmittance of the scattering structure (14) in a region corresponding to the light-shielding structure. The application relates to a light projector for a depth camera, comprising: a laser (12) for projecting first structured light (5); a projection lens (11) for adjusting the propagation path of the first structured light (5) to obtain second structured light and flood light (52); wherein the projection lens (11) is provided with a scattering structure (14), the scattering structure (14) is a pattern arranged on the projection lens (11) and used for scattering structured light, the scattering structure (14) comprises a plurality of scattering areas (141), the scattering areas (141) are non-uniformly distributed on the projection lens (11), and the length value of the scattering areas (141) in at least one direction is smaller than the length value of a corresponding structured light spot in the direction; the corresponding structured light spot is a structured light spot (51) passing through the scattering area (141). The projection lens (11) comprises at least one of a conventional optical lens device, a diffractive optical device and a metasurface optical device. The scattering structure (14) is arranged on the outermost device of the structured light spot in the propagation direction. The area proportion of the scattering areas (141) in a first area is greater than or equal to the area proportion of the scattering areas (141) in a second area; In the working state, the first area is closer to the ground in the vertical direction than the second area. The shape of the scattering areas (141) comprises at least one of a circle, an ellipse and a line. The area proportion of the scattering areas to the area of the corresponding structured light spot is less than or equal to 95%. Each scattering area (141) comprises a plurality of laser engraving etching points (142), the number of the laser engraving etching points (142) contained by the scattering areas (141) with different areas is different, and the larger the area of the scattering area (141) is, the more the laser engraving etching points (142) contained by the scattering area (141) are. Further comprising: a light-shielding structure for reducing the light transmittance of the scattering structure (14) in a region corresponding to the light-shielding structure.