Polarization depth camera

Abstract

A polarization depth camera is used for obtaining a depth image and is characterized by comprising a polarization projector and a receiver, the receiver is used for receiving a reflected signal of the polarization projector and generating a depth image; the polarization projector emits polarized light; the polarization projector comprises a light source used for emitting infrared light; the first polaroid is located on a light path of the infrared light source; the random phase plate is located between the infrared light source and the first polaroid; and the reflecting mirror surface and the infrared light source are positioned on the same side of the first polarizing film, and the reflecting mirror surface is used for reflecting the infrared light. According to the utility model, by arranging the random phase plate and the reflecting mirror surface, infrared light which cannot penetrate through the first polarizing film can penetrate through the first polarizing film after the phase is changed, so that the passing rate of the infrared light is improved, and the light emitting efficiency is improved.

Description

Technical Field

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

[0002] A polarization depth camera is a camera that uses the polarization properties of light to perform three-dimensional imaging.

[0003] Light is a transverse wave with a vibration plane and propagation direction perpendicular to each other. In addition to the characteristics of propagation direction, intensity, wavelength, etc., light also has polarization characteristics. Polarized light is divided into fully polarized light and partially polarized light, among which fully polarized light is further divided into circularly polarized light and linearly polarized light. Polarization cameras use polarization filters to only allow light with a specific vibration direction to pass through, thereby realizing the detection and analysis of the polarization state of light.

[0004] In the field of 3D imaging, polarization depth cameras can obtain depth information of objects by analyzing the polarization state of reflected light. This is because surfaces of different materials have different effects on the polarization state of light, and by detecting these changes, the shape and structure of the object can be inferred. Compared with other 3D imaging technologies (such as binocular stereo vision, structured light 3D imaging, lidar 3D imaging, etc.), polarization 3D imaging technology has its own unique advantages and application scenarios. For example, in environments with complex light or extremely high surface reflectivity, traditional 3D imaging technology may encounter difficulties, while polarization 3D imaging can provide more accurate depth information.

[0005] In general, the application prospects of polarization depth cameras are very broad, including but not limited to the development of machine vision, augmented reality (AR), virtual reality (VR) and metaverse technology.

[0006] However, the polarization projectors in the prior art all have the problems of large energy loss and low utilization rate.

[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 the present application. Utility Model Content

[0008] To this end, the utility model arranges a random phase plate and a reflective mirror so that the infrared light that cannot penetrate the first polarizer can penetrate the first polarizer after the phase is changed, thereby improving the pass rate of the infrared light and improving the light extraction efficiency.

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

[0010] Polarization projectors and receivers;

[0011] The receiver is used to receive the reflected signal of the polarization projector to generate a depth image;

[0012] The polarization projector emits polarized light;

[0013] Wherein, the polarization projector comprises:

[0014] a light source for emitting infrared light;

[0015] A first polarizer, located on the optical path of the infrared light source;

[0016] A random phase plate, located between the infrared light source and the first polarizer;

[0017] A reflective mirror surface is located on the same side of the first polarizer as the infrared light source and is used to reflect the infrared light.

[0018] Optionally, the polarization depth camera is characterized in that the reflective mirror surface wraps around a side of the first polarizer facing the infrared light source.

[0019] Optionally, the polarization depth camera is characterized in that the first polarizer completely covers the light path of the infrared light source.

[0020] Optionally, the polarization depth camera is characterized by further comprising:

[0021] The glass plays a protective role and allows the infrared light to pass through.

[0022] Optionally, the polarization depth camera is characterized in that the first polarizer is attached to the glass.

[0023] Optionally, the polarization depth camera is characterized in that the glass is connected to the reflective mirror surface to reflect infrared light that is not emitted from the glass.

[0024] Optionally, the polarization depth camera is characterized in that the distance between the random phase plate and the first polarizer is less than 2 mm.

[0025] Optionally, the polarization depth camera is characterized in that the random phase plate is attached to the first polarizer.

[0026] Optionally, the polarization depth camera is characterized in that the receiver comprises:

[0027] a second polarizer;

[0028] The TOF receiver is used to receive the reflected signal passing through the second polarizer to generate a depth image.

[0029] Optionally, the polarization depth camera is characterized in that the polarization direction of the second polarizer is perpendicular to that of the first polarizer.

[0030] Compared with the prior art, the utility model has the following beneficial effects:

[0031] According to the characteristic that the first polarizer can only penetrate 50% of the polarized light, the utility model sets a random phase plate to change the phase of the light that cannot penetrate, and uses a reflective mirror to change the direction of the light path, so that the light after the phase change is irradiated on the first polarizer again, so that the light penetrating the first polarizer reaches 75% after one reflection, and reaches more than 90% after multiple reflections, which greatly improves the light extraction efficiency, so that the light projection in the polarized state also has higher light extraction efficiency and energy utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work. By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, purposes and advantages of the utility model will become more obvious:

[0033] Figure 1 This is a schematic diagram of the structure of a polarization depth camera in an embodiment of the present utility model;

[0034] Figure 2 This is a schematic structural diagram of a polarization projector in an embodiment of the utility model;

[0035] Figure 3 This is a schematic diagram of the optical path of a polarization projector in an embodiment of the utility model;

[0036] Figure 4 This is a schematic structural diagram of a first polarizer in an embodiment of the utility model;

[0037] Figure 5 It is a structural schematic diagram of a receiver in an embodiment of the utility model.

[0038] 1- Light source;

[0039] 2- first polarizer;

[0040] 3- Random phase plate;

[0041] 4-Reflective mirror;

[0042] 5- Glass;

[0043] 6-Polarization projector;

[0044] 7-Receiver;

[0045] 8- second polarizer;

[0046] 9-TOF receiver;

[0047] 11- Infrared light;

[0048] 12- first transmitted light;

[0049] 13- first reflected light;

[0050] 14- second transmitted light;

[0051] 15-First area;

[0052] 16-Second area; DETAILED DESCRIPTION

[0053] The utility model is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the utility model, but do not limit the utility model in any form. It should be pointed out that for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the utility model. These all fall within the scope of protection of the utility model.

[0054] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present utility model 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 utility model described here, for example, can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device 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 inherent to these processes, methods, products or devices.

[0055] The present invention provides a polarization depth camera, which aims to solve the problems existing in the prior art.

[0056] The following specific embodiments are used to describe in detail the technical solution of the utility model and how the technical solution of the present application solves the above 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 embodiments of the utility model will be described below in conjunction with the accompanying drawings.

[0057] According to the characteristic that the first polarizer can only penetrate 50% of the polarized light, the utility model sets a random phase plate to change the phase of the light that cannot penetrate, and uses a reflective mirror to change the direction of the light path, so that the light after the phase change is irradiated on the first polarizer again, so that the light penetrating the first polarizer reaches 75% after one reflection, and reaches more than 90% after multiple reflections, which greatly improves the light extraction efficiency, so that the light projection in the polarized state also has higher light extraction efficiency and energy utilization rate.

[0058] Figure 1 FIG. 1 is a schematic diagram of the structure of a polarization depth camera in an embodiment of the present utility model. Figure 1 As shown, a polarization depth camera in an embodiment of the utility model includes:

[0059] Polarization projector 6 and receiver 7;

[0060] The receiver 7 is used to receive the reflected signal of the polarization projector 6 and generate a depth image;

[0061] The polarization projector 6 emits polarized light.

[0062] Specifically, the polarized projector 6 is an active light source for emitting infrared light. The infrared light emitted by the polarized projector 6 is irradiated on the target object, and after being reflected by the target object, it is received by the receiver 7 and a depth image is calculated according to a time-of-flight algorithm.

[0063] like Figure 2 As shown, the polarization projector 6 includes:

[0064] The light source 1 is used for emitting infrared light.

[0065] Specifically, light source 1 is the core part of the polarization projector, responsible for emitting infrared light, that is, light without a specific polarization direction. Infrared light can be light of any wavelength band, such as visible light, infrared light, ultraviolet light, etc. Infrared light can be infrared flood light or structured light. The light source can be various light sources, including but not limited to LED light sources, incandescent lamps, halogen lamps, fluorescent lamps (fluorescent lamps), energy-saving lamps, lasers, OLEDs (organic light-emitting diodes), plasma light sources and other light sources. Each light source has its advantages and limitations, and the selection of the light source needs to be determined according to the specific application requirements. LED light sources usually have the advantages of high brightness, long life and high energy efficiency.

[0066] The first polarizer 2 is located on the optical path of the infrared light source.

[0067] Specifically, the first polarizer 2 is located on the optical path of the light source 1. Its function is to obtain linearly polarized light from the infrared light. The first polarizer is usually composed of a multilayer film, which contains materials that can absorb or reflect light in a specific polarization direction. The number of the first polarizer is one. In some embodiments, the first polarizer has only one vibration transmission direction, and only light waves vibrating along this direction can pass through. In some embodiments, the first polarizer has at least two vibration transmission directions, and the polarization directions of light emitted from different areas of the first polarizer are different. The polarization directions of different areas on the first polarizer can be vertical or at an angle of 45 degrees, 30 degrees, 15 degrees or any other angle.

[0068] The random phase plate 3 is located between the infrared light source and the first polarizer.

[0069] Specifically, a random phase plate (RPP) is an optical element used to introduce random phase changes on the wavefront of a light beam. The surface of a random phase plate has irregular structures that introduce random phase delays on the passing light beam. This phase delay causes the wavefront of the light beam to be distorted, thereby changing the propagation characteristics and focusing performance of the light beam. The design and manufacture of a random phase plate requires precise control of the microstructure of its surface to ensure that the desired phase change can be accurately introduced into the light beam.

[0070] The reflective mirror 4 is located on the same side of the first polarizer as the infrared light source and is used to reflect the infrared light.

[0071] Specifically, the reflective mirror 4 can change the direction of the light so that it propagates along the desired path. The reflective mirror is used to reflect the light beam from the light source so that the light can be reflected and transmitted multiple times inside the polarization projector. Since the reflective mirror usually has a high reflectivity, the energy of the light can be retained to the maximum extent. In the polarization projector, the reflective mirror and the LED light source are located on the same side of the first polarizer, and can reflect the infrared light emitted by the LED light source back to the first polarizer and the random phase plate. After multiple reflections and polarization processing, more polarized light beams are finally emitted, thereby improving the light output rate.

[0072] In some embodiments, the reflective mirror surface wraps the side of the first polarizer facing the infrared light source. The reflective mirror surface wraps the side of the first polarizer facing the light source, so that all light on the light source side can only be irradiated on the reflective mirror, the light source and the first polarizer, so that the light is reflected to the maximum extent. The reflective mirror surface is in an arc shape so that the infrared light is irradiated on the first polarizer with the least number of reflections, thereby reducing light loss and improving light extraction efficiency.

[0073] In some embodiments, the first polarizer completely covers the optical path of the infrared light source. The size of the first polarizer is large enough so that the infrared light emitted from the light source is directly irradiated on the first polarizer without reflection, so that the emitted infrared light is more uniform. Since the proportion of the emitted light is the highest when it is irradiated on the first polarizer for the first time, this embodiment can ensure the uniformity of the infrared light.

[0074] In some embodiments, the random phase plate completely covers the optical path of the infrared light source. The random phase plate resets the polarization state of all penetrating infrared light, so as to reset as much light as possible.

[0075] In some embodiments, it also includes: glass 5, which plays a protective role and allows the infrared light to pass through. The glass can be ordinary glass, tempered glass, etc., which plays a protective role. The glass is transparent to allow infrared light to pass through. Depending on the type of infrared light, different types of glass can be used. For example, if the infrared light is visible light, the glass can pass the visible light. If the infrared light is infrared light, the glass can pass the infrared light, and for visible light, the glass can either pass it or not. Whether the visible light can pass can be set according to the application scenario.

[0076] In some embodiments, the first polarizer is attached to the glass. The first polarizer is attached to the glass to minimize light loss and improve light transmission rate.

[0077] In some embodiments, the glass is connected to the reflective mirror surface to reflect the infrared light that is not emitted from the glass. When the glass is connected to the reflective mirror surface, a closed space is formed inside, thereby maximizing the use of the space and achieving the best reflection effect.

[0078] In some embodiments, the distance between the random phase plate and the first polarizer is less than 2 mm. The distance between the random phase plate and the first polarizer is less than 2 mm, which can reduce light loss, facilitate installation and fixation, and improve the stability of the polarization projector.

[0079] In some embodiments, the random phase plate is attached to the first polarizer. When the random phase plate is attached to the first polarizer, light loss is minimized, and light emission rate can be increased.

[0080] Figure 3This is a schematic diagram of the optical path of a polarization depth camera in an embodiment of the utility model. When the light source projects infrared light 11, the infrared light intensity is recorded as I. After the infrared light penetrates the random phase plate 3, it is irradiated on the first polarizer 2, and 50%I penetrates the first polarizer and is emitted, which is recorded as the first transmitted light 12, and 50%I is reflected by the first polarizer, which is recorded as the first reflected light 13. After the first reflected light penetrates the random phase plate, it is irradiated on the reflective mirror 4, and then reflects and penetrates the random phase plate again, and irradiates on the first polarizer 2. Since the random phase plate changes the polarization state of the light to a random state, 50%*50%I penetrates the first polarizer 2, which is recorded as the second transmitted light 14, and 50%*50%I is reflected again by the first polarizer 2, which is recorded as the second reflected light. At this time, the light penetrating the first polarizer is 0.75I. When the second reflected light continues to repeat the above path, more light will be emitted from the first polarizer, so that the final output light efficiency can reach more than 90%.

[0081] Figure 4 FIG. 1 is a schematic diagram of the structure of a first polarizer in an embodiment of the utility model. Figure 4 As shown, the first polarizer is divided into at least two regions, and the adjacent regions have different polarization directions. The first polarizer is divided into different regions, and each region has the same polarization direction. Figure 4 The first polarizer is divided into four different regions. Two opposite regions have the same polarization direction, and two adjacent regions have different polarization directions. The polarization directions are horizontal polarization and vertical polarization.

[0082] Figure 5 Schematic diagram of the structure of a receiver in the embodiment of the utility model. Figure 5 As shown, a receiver in an embodiment of the utility model includes:

[0083] A second polarizing plate 8;

[0084] The TOF receiver 9 is used to receive the reflected signal passing through the second polarizer to generate a depth image.

[0085] Specifically, the second polarizer 8 is located in front of the TOF receiver 9. Only the infrared light processed by the second polarizer 8 can be received by the TOF receiver 9. After being processed by the second polarizer, the infrared light received by the TOF receiver is purer and can filter out the influence of stray light, making the generated depth image clearer. The second polarizer 8 is attached to the TOF receiver 9 to reduce light loss.

[0086] In some embodiments, the polarization direction of the second polarizer is perpendicular to that of the first polarizer. The second polarizer and the first polarizer each have only one polarization direction, and the two are perpendicular. In this case, the data obtained only contains specific information, which is suitable for obtaining data on a specific object. For example, the epidermis information is filtered out, and the information on the dermis layer of the human body is obtained.

[0087] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the 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, and 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 range consistent with the principles and novel features disclosed herein.

[0088] 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 can make various modifications or variations within the scope of the claims, which does not affect the essence of the present invention.

Claims

1. A polarization depth camera for obtaining a depth image, characterized in that: include: Polarization projectors and receivers; The receiver is used to receive the reflected signal of the polarization projector to generate a depth image; The polarization projector emits polarized light; Wherein, the polarization projector comprises: a light source for emitting infrared light; A first polarizer, located on the optical path of the infrared light source; A random phase plate, located between the infrared light source and the first polarizer; A reflective mirror surface is located on the same side of the first polarizer as the infrared light source and is used to reflect the infrared light.

2. A polarization depth camera according to claim 1, characterized in that: The reflective mirror surface wraps a side of the first polarizer facing the infrared light source.

3. The polarization depth camera according to claim 1, characterized in that: The first polarizer completely covers the optical path of the infrared light source.

4. The polarization depth camera according to claim 1, characterized in that: Also includes: The glass plays a protective role and allows the infrared light to pass through.

5. A polarization depth camera according to claim 4, characterized in that: The first polarizer is attached to the glass.

6. The polarization depth camera according to claim 4, characterized in that: The glass is connected to the reflective mirror surface to reflect the infrared light that is not emitted from the glass.

7. The polarization depth camera according to claim 1, characterized in that: The distance between the random phase plate and the first polarizer is less than 2 mm.

8. The polarization depth camera according to claim 1, characterized in that: The random phase plate is attached to the first polarizing plate.

9. The polarization depth camera according to claim 1, characterized in that: The receiver comprises: a second polarizer; The TOF receiver is used to receive the reflected signal passing through the second polarizer to generate a depth image.

10. The polarization depth camera according to claim 9, characterized in that: The polarization direction of the second polarizer is perpendicular to that of the first polarizer.

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