Depth camera

Abstract

A depth camera is characterized in that the depth camera comprises a projector used for projecting polarized structured light spots and floodlight at the same time; wherein the light spot of the structured light is the same as the optical axis of the floodlight; and the first receiver is used for receiving signals of the structured light spot and the floodlight. Structured light and floodlight are projected at the same time through the projector, and a structured light image and a TOF image can be obtained at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of depth cameras, and in particular to a depth camera. Background Art

[0002] The projector in the depth camera is a key component used in depth imaging technology. It is responsible for projecting laser light onto the surface of the object being measured in order to obtain depth information.

[0003] Structured light technology and Time of Flight (TOF) technology are the two most widely used technologies in depth cameras. Existing technologies can combine structured light technology and Time of Flight (TOF) technology based on different application scenarios to selectively utilize structured light depth or Time of Flight depth for different application scenarios to obtain better depth data.

[0004] There are two main technical paths when combining structured light technology with TOF technology.

[0005] The first method is to integrate a structured light projector and a floodlight source into a single depth camera. By controlling the activation and deactivation of the structured light projector and the floodlight source, both structured light and floodlight can be obtained. However, this method has low integration and large size, making it difficult to meet miniaturization requirements.

[0006] The second method uses a switch between structured light and floodlight to achieve miniaturization, but it cannot project both structured light and floodlight simultaneously. In scenes where fill light is needed, an additional fill light is still required, which has a limited adaptability.

[0007] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the utility model. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of this application. Utility Model Content

[0008] To this end, the present invention proposes a depth camera to solve the problems in the prior art.

[0009] The utility model provides a depth camera, characterized by comprising:

[0010] A projector, configured to simultaneously project a polarized structured light spot and a flood light; wherein the optical axes of the structured light spot and the flood light are the same;

[0011] The first receiver is configured to receive signals of the structured light spot and the flood light.

[0012] Optionally, the depth camera is characterized in that the projector includes:

[0013] flood light source;

[0014] A first polarizer is located on the outgoing light path of the floodlight source;

[0015] a display screen, located between the floodlight source and the first polarizer, configured to control the emitted light into structured light by displaying a pattern;

[0016] a phase plate, located between the display screen and the first polarizer, for changing the polarization state of light passing therethrough;

[0017] The reflecting mirror is located on the same side of the first polarizer as the phase plate and is used to reflect light to the first polarizer.

[0018] Optionally, the depth camera is characterized in that the distance between the flood light source and the first polarizer is not greater than 10 times the wavelength of the structured light spot.

[0019] Optionally, the depth camera is characterized in that the distance between the phase plate and the first polarizer is no more than 1 mm.

[0020] Optionally, the depth camera is characterized in that the projector includes:

[0021] Structured light dot matrix, used to provide coded structured light;

[0022] A floodlight, used to provide floodlighting; the floodlight is in a circular shape;

[0023] The structured light dot matrix is ​​located in the floodlight.

[0024] Optionally, the depth camera further comprises:

[0025] RGB receiver, used to generate RGB images.

[0026] Optionally, the depth camera is characterized in that the phase plate is a 1 / 8 wave plate or a random phase plate.

[0027] Optionally, the depth camera further comprises:

[0028] A processor is configured to perform living body recognition based on the speckle pattern and infrared image generated by the first receiver.

[0029] Optionally, the depth camera further comprises:

[0030] The second receiver is configured to receive signals of the structured light spot and the flood light.

[0031] Optionally, the depth camera is characterized in that the first receiver and the second receiver are symmetrically arranged around the projector.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The utility model adopts a projector to project polarized structured light spots and floodlights, and adopts a first receiver to receive them, so that the structured light and the floodlight have the same viewing angle and time, which greatly reduces the amount of subsequent image processing and is conducive to the rapid acquisition of efficient processing of structured light images and floodlight images. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without inventive work. By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, purposes and advantages of the present invention will become more apparent:

[0035] Figure 1 This is a schematic structural diagram of a depth camera according to an embodiment of the present invention;

[0036] Figure 2 This is a schematic structural diagram of a projector in an embodiment of the present utility model;

[0037] Figure 3 This is a schematic structural diagram of another projector in an embodiment of the present utility model;

[0038] Figure 4 This is a schematic diagram of the structure of another depth camera in an embodiment of the present utility model;

[0039] Figure 5 This is a schematic diagram of the structure of another depth camera in an embodiment of the present utility model;

[0040] Figure 6 This is a partial schematic diagram of the light spot in the embodiment of the present utility model;

[0041] Figure 7 Schematic diagram of the structure of another depth camera in an embodiment of the present invention.

[0042] 1- Flood light source;

[0043] 2- first polarizer;

[0044] 3-Phase plate;

[0045] 4-reflective mirror;

[0046] 5-Glass;

[0047] 6-Polarized projector;

[0048] 7-projector;

[0049] 8- first receiver;

[0050] 10-RGB receiver;

[0051] 11- Processor;

[0052] 12 - second receiver;

[0053] 13-Structured light dot matrix;

[0054] 14-Floodlight;

[0055] 15-Display screen; DETAILED DESCRIPTION

[0056] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art further understand the present invention, but are not intended to limit the present invention in any way. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the scope of the present invention. These modifications and improvements are all within the scope of protection of the present invention.

[0057] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or that are inherent to these processes, methods, products or apparatus.

[0058] The present invention provides a depth camera to solve the problems existing in the prior art.

[0059] The following specific embodiments describe in detail the technical solution of the present invention and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The following embodiments of the present invention are described in conjunction with the accompanying drawings.

[0060] Figure 1 FIG. 1 is a schematic diagram of the structure of a depth camera in an embodiment of the present utility model. Figure 1 As shown, a depth camera in an embodiment of the present invention includes:

[0061] The projector 7 is used to simultaneously project polarized structured light spots and floodlights.

[0062] Specifically, the structured light spot and the flood light have the same optical axis. Unlike the prior art, which switches between projecting structured light and flood light, the structured light spot and flood light in this embodiment are projected simultaneously. Unlike the prior art, which simultaneously configures a structured light projector and a flood light projector, the structured light spot and flood light projected by the projector in this embodiment have the same optical axis and therefore have the same projection position, making them more user-friendly for later image processing. The structured light spot can be a coded pattern of various structured lights, such as speckle and stripes. Preferably, both the structured light spot and the flood light are infrared light.

[0063] The first receiver 8 is configured to receive the structured light spot and the flood light signal.

[0064] Specifically, the first receiver can simultaneously receive the signals of the structured light spot and the floodlight, so that the received image has the same field of view, and the generated structured light image and floodlight image naturally have the characteristics of alignment, so that the structured light depth and TOF depth can be accurately fused and processed.

[0065] Figure 2 This is a schematic diagram of the structure of a projector in an embodiment of the present utility model. Figure 2 As shown, a projector in an embodiment of the present invention includes:

[0066] Floodlight 1.

[0067] Specifically, the floodlight source can be any floodlight source in the prior art to emit structured light spots. In this embodiment, the floodlight source is the only light source of the depth camera.

[0068] The first polarizer 2 is located on the light path of the floodlight source.

[0069] Specifically, the first polarizer can be a polarizer with a single direction or a polarizer with different polarization directions. Those skilled in the art can select a polarizer with appropriate polarization characteristics based on the specific application scenario. The first polarizer 2 ensures that all light emitted by the projector has polarization characteristics.

[0070] The display screen 15 is located between the floodlight source and the first polarizer, and controls the emitted light to be structured light by displaying a pattern.

[0071] Specifically, the display's size can block the floodlight's emission angle, ensuring that all floodlight is directed directly onto the display. The display can display different patterns, transforming the light that passes through it into different structured light forms. Different images displayed on the display will produce different structured light forms, allowing for a variety of choices based on application scenarios.

[0072] The phase plate 3 is located between the light source and the first polarizer, and is used to change the polarization state of the light passing through.

[0073] Specifically, phase plate 3 is used to change the polarization state of light, so that light that fails to penetrate the first polarizer can pass through the first polarizer after changing its polarization state. The phase plate can be a random phase plate or a 1 / 8 wave plate. The phase plate changes the polarization state of light, that is, modulates the phase of the polarization state. This does not affect the phase in the TOF technology and therefore does not affect the TOF depth value obtained by the TOF technology.

[0074] When the phase plate is a random phase plate, the light reflected by the second polarizer is converted to a random phase after passing through the random phase plate. This results in 50% of the light hitting the second polarizer passing through it. The remaining light is reflected by the second polarizer again. This cycle repeats, and the overall light extraction efficiency reaches 90%.

[0075] When the phase plate is a 1 / 8 wave plate, the light reflected by the second polarizer will have its polarization rotated by 1 / 8 after passing through the 1 / 8 wave plate. After passing through the 1 / 8 wave plate twice, the polarization state changes by 90 degrees, allowing it to pass through the second polarizer after a single reflection, resulting in an overall light output efficiency exceeding 95%. Furthermore, using a 1 / 8 wave plate can reduce the number of light reflections within the projector, minimizing light loss.

[0076] The reflective mirror 4 is located on the same side of the first polarizer as the light source and is used to reflect light to the first polarizer.

[0077] Specifically, the reflective mirror is used to change the direction of light so that the light reflected by the first polarizer is directed toward the second polarizer again.

[0078] In some embodiments, a gap is provided between the display screen and the reflective mirror surface, so that the portion of light emitted by the floodlight source that does not pass through the display screen is reflected by the reflective mirror surface and directed toward the first polarizer. The portion of the reflective mirror surface between the floodlight source and the display screen is designated as the first portion, and the portion of the reflective mirror surface between the display screen and the first polarizer is designated as the second portion. The first and second portions have different curvatures, ensuring that light from both the first and second portions is uniformly incident on the first polarizer.

[0079] This embodiment allows the light blocked by the first polarizer to be emitted from the first polarizer after changing its polarization state. At the same time, the light that fails to penetrate the display screen can also be irradiated on the first polarizer in the form of floodlight, thereby greatly improving the light extraction efficiency, reducing light loss, improving energy utilization efficiency, reducing the heat generated by the projector, and facilitating the long-term stable operation of the projector.

[0080] In some embodiments, the distance between the floodlight source and the first polarizer is no greater than 10 times the wavelength of the structured light spot.

[0081] In some embodiments, the distance between the phase plate and the first polarizer is no greater than 1 mm.

[0082] Figure 3 This is a schematic diagram of the structure of another projector in the embodiment of the present utility model. Figure 3 As shown, another projector in the embodiment of the present invention includes a structured light matrix 13 and a floodlight 14 .

[0083] The structured light dot matrix 13 is used to provide coded structured light and obtain a structured light depth image. The structured light dot matrix 13 and the first receiver form a structured light system, which can perform structured light measurement and obtain structured light depth data.

[0084] The floodlight 14 is used to provide floodlight illumination and acquire a TOF depth image. The floodlight 14 and the first receiver form a TOF system that can perform TOF measurement and acquire TOF depth data.

[0085] The structured light array is located in the center. The floodlights are positioned around the array, forming a closed ring to provide uniform floodlighting. The center of the array coincides with the center of the floodlights. In the image received by the first receiver, the pixels illuminated by the structured light have higher brightness. Therefore, by extracting the image based on brightness, a structured light image can be obtained, and the entire image can be considered a TOF image.

[0086] This embodiment arranges structured light dot matrix and floodlight, and can project structured light and floodlight at the same time, or can project structured light or floodlight separately, with a higher degree of freedom, realizing the selection of various application scenarios.

[0087] Figure 4 FIG. 1 is a schematic diagram of the structure of another depth camera in an embodiment of the present utility model. Figure 4 As shown, compared with the above embodiment, another depth camera in the embodiment of the present invention further includes:

[0088] The RGB receiver 10 is used to generate an RGB image.

[0089] Specifically, RGB images are produced using visible light, which has a different wavelength than infrared light. For the human body, RGB images can capture images of the skin's surface, such as the face or palm prints. Infrared images, on the other hand, may contain vein information. Therefore, the information contained in RGB and infrared images may differ. By jointly processing RGB and infrared images (structured light or TOF images), the information dimension of the target object can be increased, improving the accuracy of target object recognition.

[0090] Figure 5 FIG. 1 is a schematic diagram of the structure of another depth camera in an embodiment of the present utility model. Figure 5 As shown, compared with the above embodiment, another depth camera in the embodiment of the present invention further includes:

[0091] The processor 11 is configured to perform living body recognition according to the speckle pattern and infrared image generated by the first receiver.

[0092] Specifically, liveness recognition is a key step in biometrics. Figure 6 As shown in the figure, a is a magnified image of a local spot on a target person; b is a magnified image of a local spot on a plaster target person; c is a magnified image of a live target person; and d is a magnified image of a local spot on a silicone target person. Different materials have different optical imaging effects, and speckle has different diffusion effects. By training with multiple sets of speckle data, different materials can be distinguished, which can more accurately determine liveness.

[0093] Figure 7 FIG. 1 is a schematic diagram of the structure of another depth camera in an embodiment of the present utility model. Figure 7 As shown, compared with the above embodiment, another depth camera in the embodiment of the present invention further includes:

[0094] The second receiver 12 is configured to receive the structured light spot and the flood light signal.

[0095] Specifically, the first receiver and the second receiver are symmetrically arranged around the projector. The projector is located on the perpendicular bisector of the line connecting the first and second receivers. The first and second receivers receive the same signal and are symmetrically positioned relative to the projector.

[0096] In some embodiments, a second polarizer is provided in the incident direction of both the first receiver and the second receiver. In this case, the first receiver and the second receiver form a binocular system, and the information is the same. The binocular depth can be calculated in addition to TOF and structured light, thereby improving the dimension of data acquisition. The polarization direction of the second polarizer and the polarization direction of the light projected by the projector can affect the information obtained, filter out the influence of stray light, and improve the signal-to-noise ratio. When the polarization direction of the second polarizer is perpendicular to the polarization direction of the light projected by the projector, if it is irradiated on the skin, the information of the surface layer of the skin can be filtered out, and the vein information such as the blood vessels in the dermis can be obtained, which is used for palm vein recognition, facial vein recognition, etc.

[0097] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the utility model. Various modifications to these embodiments will be obvious to professionals and technicians in this field. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the utility model. Therefore, the utility model will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0098] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A depth camera, characterized in that: include: A projector, configured to simultaneously project a polarized structured light spot and a flood light; wherein the optical axes of the structured light spot and the flood light are the same; The first receiver is configured to receive signals of the structured light spot and the flood light.

2. A depth camera according to claim 1, characterized in that: The projector comprises: flood light source; A first polarizer is located on the outgoing light path of the floodlight source; a display screen, located between the floodlight source and the first polarizer, configured to control the emitted light into structured light by displaying a pattern; a phase plate, located between the display screen and the first polarizer, for changing the polarization state of light passing therethrough; The reflecting mirror is located on the same side of the first polarizer as the phase plate and is used to reflect light to the first polarizer.

3. The depth camera according to claim 2, wherein: The distance between the floodlight source and the first polarizer is no greater than 10 times the wavelength of the structured light spot.

4. The depth camera according to claim 2, wherein: The distance between the phase plate and the first polarizer is no greater than 1 mm.

5. The depth camera according to claim 1, wherein: The projector comprises: Structured light dot matrix, used to provide coded structured light; A floodlight, used to provide floodlighting; the floodlight is in a circular shape; The structured light dot matrix is ​​located in the floodlight.

6. The depth camera according to claim 1, wherein: Also includes: RGB receiver, used to generate RGB images.

7. The depth camera according to claim 2, wherein: The phase plate is a 1 / 8 wave plate or a random phase plate.

8. The depth camera according to claim 1, wherein: Also includes: A processor is configured to perform living body recognition based on the speckle pattern and infrared image generated by the first receiver.

9. The depth camera according to claim 1, wherein: Also includes: The second receiver is configured to receive signals of the structured light spot and the flood light.

10. The depth camera according to claim 9, characterized in that: The first receiver and the second receiver are symmetrically arranged around the projector.

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