Three-dimensional imaging device and electronic equipment

Abstract

The utility model provides a three-dimensional imaging device and electronic equipment, and relates to the technical field of biological recognition, the three-dimensional imaging device comprises a light source, a polarization device and a light sensing unit which are sequentially arranged along a light path, collection light emitted by the light source is reflected by a target object and then enters the light sensing unit, and the collection light enters the light sensing unit before entering the light sensing unit. A plurality of time sequence polarized lights in different polarization directions are formed through time-sharing polarization modulation of the polarization device, the light sensing unit receives the time sequence polarized lights in sequence according to the time sequence and images the time sequence polarized lights respectively, the contour surface of the target object can be reconstructed more accurately, the reconstructed contour surface is closer to the actual contour surface of the target object, and the accuracy of the contour surface reconstruction is improved. And the identification precision can be improved.

Description

Technical Field

[0001] This application relates to the field of biometric technologies, and more particularly, to a three-dimensional imaging device and an electronic device. Background Art

[0002] With the development of portable terminal devices, the application of biometric technologies has become more and more extensive and in-depth. Taking electronic devices as an example, fingerprint recognition, face recognition, etc. have been increasingly applied in the screen wake-up of devices and the identity authentication steps of various programs, improving the security of the devices and the flexibility of the usage methods.

[0003] Currently, the main solutions for implementing face recognition include binocular vision solutions, time-of-flight solutions, structured light solutions, etc. Among them, the binocular vision solution has a limited range of use because the reconstruction accuracy is proportional to the camera baseline length; the cost of time-of-flight cameras is relatively high, and they are limited by the time resolution, so the accuracy of three-dimensional imaging is not high; although the structured light solution has the advantage of high imaging accuracy, its response speed is slow and the frame rate is low, and as the imaging distance increases, the imaging accuracy decreases. Therefore, another polarization three-dimensional imaging technology that can be used for face recognition has also been gradually developed, but currently, the polarization three-dimensional imaging technology usually has problems with poor recognition accuracy. Summary of the Utility Model

[0004] The purpose of this application is to provide a three-dimensional imaging device and an electronic device for the deficiencies in the above-mentioned existing technologies.

[0005] To achieve the above purpose, the technical solutions adopted in the embodiments of this application are as follows:

[0006] On the one hand, an embodiment of this application provides a three-dimensional imaging device, including a light source, a polarization device, and an image sensor arranged in sequence along the optical path. The image sensor includes photosensitive units. The acquisition light emitted by the light source is reflected by the target object and then enters the photosensitive units. Before entering the photosensitive units, the acquisition light is time-division polarization modulated by the polarization device to form multiple sequential polarized lights with different polarization directions, and the multiple sequential polarized lights respectively carry polarization information corresponding to the contour surface of the target object and sequentially enter the photosensitive units.

[0007] Optionally, the polarization device is located between the light source and the target object. The acquisition light emitted by the light source is time-division polarization modulated by the polarization device to form multiple sequential polarized lights. After being sequentially reflected by the target object, the multiple sequential polarized lights respectively carry polarization information corresponding to the contour surface of the target object and sequentially enter the photosensitive units.

[0008] Optionally, the light source has multiple light-emitting surfaces, the polarization device includes multiple polarization elements corresponding one-to-one to the multiple light-emitting surfaces, each polarization element is located on the light-emitting side of the corresponding light-emitting surface, and among the multiple polarization elements, the polarization directions of any two polarization elements are different.

[0009] Optionally, the included angle between the polarization directions of any two polarization elements is greater than 10 degrees.

[0010] Optionally, the polarization device includes a first polarizer and a liquid crystal phase retarder located on the light-emitting side of the light source, and the first polarizer is located between the light source and the liquid crystal phase retarder.

[0011] Optionally, the polarization device includes a first polarizer and a driver connected in a driving manner. The first polarizer is located on the light-emitting side of the light source, and the driver is used to drive the first polarizer to rotate around the optical axis of the light source.

[0012] Optionally, a second polarizer is further disposed between the object and the photosensitive unit.

[0013] Optionally, the second polarizer is attached to the photosensitive surface of the image sensor.

[0014] Optionally, the second polarizer is integrated into the image sensor.

[0015] Optionally, the polarization direction of the second polarizer is the same as the polarization direction of one of the multiple time-sequential polarized lights.

[0016] Optionally, the polarization device is located between the object and the photosensitive unit. The acquisition light emitted by the light source assembly is reflected by the object and then subjected to time-division polarization modulation by the polarization device to form multiple time-sequential polarized lights, and the multiple time-sequential polarized lights are incident on the photosensitive unit in sequence, each carrying polarization information corresponding to the contour surface of the object.

[0017] Optionally, the polarization device includes a first polarizer and a liquid crystal phase retarder located on the photosensitive side of the photosensitive unit, and the liquid crystal phase retarder is located between the first polarizer and the photosensitive unit.

[0018] Optionally, the polarization device includes a first polarizer and a driver connected in a driving manner. The first polarizer is located on the photosensitive side of the photosensitive unit, and the driver is used to drive the first polarizer to rotate around the optical axis of the photosensitive unit.

[0019] Optionally, a second polarizer is further disposed between the light source and the object.

[0020] Optionally, the polarization direction of the second polarizer is the same as the polarization direction of one of the multiple time-sequential polarized lights.

[0021] Optionally, a filter is further disposed on the photosensitive side of the photosensitive unit. The wavelength band of the acquisition light is the target wavelength band, and the filter is used to filter out light outside the target wavelength band.

[0022] On the other hand, an embodiment of the present application provides a three-dimensional imaging method, and the method includes:

[0023] Control the photosensitive unit to receive multiple time-sequential polarized lights in a preset time-sequential order and form multiple polarized images, where the polarization directions of any two time-sequential polarized lights are different;

[0024] Obtain the polarization information corresponding to each pixel in the photosensitive unit according to the multiple polarized images;

[0025] Obtain the normal vector information of each microelement in the target object according to the polarization information corresponding to each pixel in the photosensitive unit and the preset mapping relationship between each pixel in the photosensitive unit and each microelement in the target object;

[0026] Obtain the three-dimensional contour information of the target object according to the normal vector information of each microelement in the target object and the position information of each pixel.

[0027] On the other hand, an embodiment of the present application provides a face recognition method, and the method includes:

[0028] Control the photosensitive unit to receive multiple time-sequential polarized lights in a preset time-sequential order and form multiple polarized images, where the acquisition light emitted by the light source is reflected by the target object and then incident on the photosensitive unit, and before the acquisition light is incident on the photosensitive unit, it is time-division polarization modulated by a polarization device to form multiple time-sequential polarized lights with different polarization directions, and the pixel value of the polarized image includes the polarization information corresponding to the contour surface of the target object;

[0029] Perform face recognition according to the multiple polarized images and obtain a face recognition result, where the face recognition includes: face matching and / or anti-counterfeiting recognition.

[0030] On yet another aspect, an embodiment of the present application provides an electronic device, including a device main body and any one of the above three-dimensional imaging devices, and the three-dimensional imaging device is located in the device main body.

[0031] The beneficial effects of the present application include:

[0032] The present application provides a three-dimensional imaging device and an electronic device, including a light source, a polarization device, and an image sensor sequentially arranged along the optical path. The image sensor includes a photosensitive unit. The acquisition light emitted by the light source is reflected by the target object and then incident on the photosensitive unit. Before the acquisition light is incident on the photosensitive unit, it is time-division polarization modulated by the polarization device to form multiple time-sequential polarized lights with different polarization directions. The photosensitive unit sequentially receives each time-sequential polarized light and images it separately. By using the characteristic that the degree of change in the polarization state of light at each point in the target object is different, the contour surface of the target object can be reconstructed more accurately, making the reconstructed contour surface closer to the actual contour surface of the target object, which helps to improve the recognition accuracy. Description of the Drawings

[0033] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application, and thus should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0034] Figure 1 One of the schematic structural diagrams of a three-dimensional imaging device provided by an embodiment of the present application;

[0035] Figure 2 One of the schematic structural diagrams of a light source and a polarization device provided by an embodiment of the present application;

[0036] Figure 3 The schematic structural diagram of a second linear polarizer and a photosensitive unit provided by an embodiment of the present application;

[0037] Figure 4 Two of the schematic structural diagrams of a three-dimensional imaging device provided by an embodiment of the present application;

[0038] Figure 5 Three of the schematic structural diagrams of a three-dimensional imaging device provided by an embodiment of the present application;

[0039] Figure 6 Two of the schematic structural diagrams of a light source and a polarization device provided by an embodiment of the present application;

[0040] Figure 7 Four of the schematic structural diagrams of a three-dimensional imaging device provided by an embodiment of the present application;

[0041] Figure 8 Five of the schematic structural diagrams of a three-dimensional imaging device provided by an embodiment of the present application;

[0042] Figure 9 Six of the schematic structural diagrams of a three-dimensional imaging device provided by an embodiment of the present application;

[0043] Figure 10 The schematic flow diagram of a three-dimensional imaging method provided by an embodiment of the present application.

[0044] Icons: 100 - human face; 200 - light source; 210 - light-emitting surface; 300 - collected light; 400 - polarization device; 401 - polarization element; 410, 440, 450, 480 - first linear polarizer; 420, 460 - liquid crystal phase retarder; 430, 470 - driver; 500 - photosensitive unit; 600 - second linear polarizer. Detailed implementation manners

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Apparently, the described embodiments are some, but not all, of the embodiments of this application. It should be noted that, without conflict, the various features in the embodiments of this application can be combined with each other, and the combined embodiments are still within the protection scope of this application.

[0046] In the description of this application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this application is usually placed during use. It is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0047] In the description of this application, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

[0048] To optimize the imaging effect and improve the recognition accuracy, this application proposes a three-dimensional imaging device that can emit acquisition light towards a target object and receive the light reflected by the target object. Among them, before the three-dimensional imaging device receives the acquisition light, the acquisition light is first modulated in time-division polarization to form multiple sequential polarized lights with a time sequence. In this way, the three-dimensional imaging device can sequentially receive multiple sequential polarized lights according to the time sequence and image them respectively. By comprehensively analyzing the images formed by each sequential polarized light and the positions of each received pixel, the contour surface of the target object can be reconstructed more accurately, which helps to improve the recognition accuracy. Of course, for the convenience of understanding, the embodiments of this application will be described below with reference to the accompanying drawings.

[0049] Please refer to Figure 1, which shows a three-dimensional imaging device including a light source 200, a polarization device 400, and an image sensor. The image sensor includes a photosensitive unit 500. Among them, the light source 200 emits acquisition light 300 towards the target object. After being reflected by the target object, the acquisition light 300 is received by the photosensitive unit 500, facilitating the photosensitive unit 500 to image it. During this process, an optical path is formed by the propagation path of the acquisition light 300. Correspondingly, both the light source 200 and the photosensitive unit 500 are located in the optical path and are arranged in sequence along the optical path.

[0050] In order to more accurately reconstruct the contour surface of the target object, the polarization device 400 can be arranged in the optical path between the light source 200 and the photosensitive unit 500. In this way, before the acquisition light 300 enters the photosensitive unit 500, the polarization device 400 will perform polarization modulation on the acquisition light 300 in chronological order, so as to form multiple sequential polarized lights with chronological order, and the polarization directions of any two sequential polarized lights are different. In this way, it is possible to utilize the characteristic that the polarization directions of the sequential polarized lights are different to facilitate better obtaining polarization information during subsequent analysis.

[0051] Therefore, when the multiple sequential polarized lights formed by the modulation of the polarization device 400 enter the photosensitive unit 500, each of them will carry polarization information corresponding to the contour surface of the target object. The photosensitive unit 500 sequentially receives each sequential polarized light according to the time sequence and images them respectively. By utilizing the characteristic that the degree of change in the polarization state of light for each point in the target object is different, polarization information can be obtained by comprehensively analyzing the images formed by each sequential polarized light, and the degree of change in the polarization state of light can be obtained using the polarization information, and then the normal vector of this position in the target object can be determined. Combining this with the positions of each receiving pixel in the photosensitive unit 500, the contour surface of the target object can be more accurately reconstructed, making the reconstructed contour surface closer to the actual contour surface of the target object.

[0052] In this way, in the scenario of face 100 recognition, when it is necessary to input the target face 100, using the aforementioned three-dimensional imaging device can make the input information closer to the actual contour surface of the target face 100. In this way, when determining the information of the face 100 to be recognized collected during the subsequent recognition process based on the input information, it can be more accurately determined whether the face 100 to be recognized is the target face 100. Of course, when collecting the information of the face 100 to be recognized, using the aforementioned three-dimensional imaging device can also make the collected information of the face 100 to be recognized closer to the actual contour surface of the face 100 to be recognized, thereby improving the accuracy of recognition.

[0053] It should be understood that the target object in this application can be Figure 1The human face 100 in it, the parts in the human face 100 (such as cheeks, nose, eyes), of course, it is not limited to this, and it can also be other objects with three-dimensional dimensions, such as fingers, palms, etc. For the convenience of understanding, the human face 100 will be used as an example for description hereinafter.

[0054] By setting the polarization device 400 in the optical path through the foregoing solution, in actual setting, the polarization device 400 can be selectively set between the light source 200 and the target object, or the polarization device 400 can be set between the target object and the photosensitive unit 500. Specifically, it can be reasonably selected according to the actual application scenario and requirements. The following will be described separately according to different positions of the polarization device 400 in the optical path.

[0055] Please refer to Figure 1 , which shows a three-dimensional imaging device with the polarization device 400 located between the light source 200 and the target object. When it is necessary to reconstruct the contour surface of the human face 100, the acquisition light 300 is emitted from the light source 200 towards the human face 100. The acquisition light 300 first enters the polarization device 400, and the polarization device 400 performs polarization modulation on the acquisition light 300 in chronological order, thereby forming multiple time-sequential polarized lights. And any two time-sequential polarized lights still satisfy that the polarization directions are different from each other. Such multiple time-sequential polarized lights will enter the human face 100 in chronological order, and after being reflected by the human face 100 in chronological order, each time-sequential polarized light will carry the polarization information corresponding to the contour surface of the human face 100, and then continue to be received and imaged by the photosensitive unit 500 in chronological order, so as to more accurately reconstruct the contour surface of the human face 100.

[0056] For the three-dimensional imaging device with the polarization device 400 located between the light source 200 and the target object, when forming multiple time-sequential polarized lights, it may include but is not limited to the following examples:

[0057] In one possible example: Please refer to Figure 2 , which respectively shows multiple light-emitting surfaces 210 of the light source 200 and multiple polarization elements 401 included in the polarization device 400. Among them, the number of light sources 200 can be one. The surface of the light source 200 capable of emitting light can be divided into multiple separate light-emitting surfaces 210. The adjacent light-emitting surfaces 210 can be adjacent (such as shown in Figure 2 ) or spaced apart, and the present application does not limit it. Of course, the light source 200 can also be multiple sub-light sources 200 arranged in a two-dimensional array. Each sub-light source 200 corresponds to one light-emitting surface 210, thereby forming multiple light-emitting surfaces 210. Among them, the multiple sub-light sources 200 can be an integrated and packaged whole light source 200, or multiple independent and separated ones, as long as it can provide multiple light-emitting surfaces 210.

[0058] The polarization device 400 includes a plurality of polarization elements 401, and the plurality of polarization elements 401 correspond one-to-one to the plurality of light-emitting surfaces 210, so that each light-emitting surface 210 has a polarization element 401 on its light-emitting side, facilitating the incident of the collected light 300 emitted from each light-emitting surface 210 to the corresponding polarization element 401 smoothly. Among them, the polarization element 401 can modulate the incident light into linearly polarized light. Therefore, the polarization direction is the linearly polarized direction. And the polarization directions of any two polarization elements 401 are different (as Figure 2 the dotted lines in the polarization element 401 in the figure indicate the polarization direction of the polarization element 401, and there is an angle between any two dotted lines or the extensions of the dotted lines), so that it is convenient for any two of the multiple sequential polarized lights formed subsequently to have different polarization directions. The plurality of polarization elements 401 can be different polarization regions in the same polarizing film, or can be multiple separate polarizing films.

[0059] When Figure 2 forming a plurality of sequential polarized lights through the light source 200 and the polarization device 400 shown: The time periods for the respective light-emitting surfaces 210 of the light source 200 to emit light are controlled to be different. For example, the plurality of light-emitting surfaces 210 are controlled to sequentially emit the collected light 300 in chronological order, and at the same time, only one light-emitting surface 210 emits the collected light 300. In this way, the collected light 300 emitted from each light-emitting surface 210 will be incident on the polarization device 400 at different times. In this way, the polarization device 400 can perform polarization modulation on the collected light 300 emitted from each light-emitting surface 210 in chronological order, thereby forming a plurality of sequential polarized lights with a time sequence. Such a plurality of sequential polarized lights with a time sequence will be incident on the human face 100 in chronological order, and after being reflected by the human face 100 in chronological order, each sequential polarized light will carry polarization information corresponding to the contour surface of the human face 100, and then continue to be received and imaged by the photosensitive unit 500 in chronological order, so as to more accurately reconstruct the contour surface of the human face 100.

[0060] For example Figure 2As shown, the light source 200 has four light-emitting surfaces 210, namely light-emitting surface A1, light-emitting surface A2, light-emitting surface A3, and light-emitting surface A4, and the four light-emitting surfaces 210 emit light in sequence according to the time sequence. Correspondingly, the polarization device 400 has four polarization elements 401, namely polarization element C1, polarization element C2, polarization element C3, and polarization element C4. Among them, the light-emitting surface A1 corresponds to the polarization element C1, the light-emitting surface A2 corresponds to the polarization element C2, the light-emitting surface A3 corresponds to the polarization element C3, and the light-emitting surface A4 corresponds to the polarization element C4. In the first time period, only the light-emitting surface A1 emits the light ray B1; in the second time period, only the light-emitting surface A2 emits the light ray B2; in the third time period, only the light-emitting surface A3 emits the light ray B3; in the fourth time period, only the light-emitting surface A4 emits the light ray B4. The light rays B1, B2, B3, and B4 reach the polarization device 400 in sequence according to the time sequence. Specifically, the light ray B1 first enters the polarization element C1, and after being polarization-modulated by the polarization element C1, it exits in the same polarization direction as the polarization element C1 to form the first-time-sequence polarized light; then, the light ray B2 enters the polarization element C2, and after being polarization-modulated by the polarization element C2, it exits in the same polarization direction as the polarization element C2 to form the second-time-sequence polarized light; subsequently, the light ray B3 enters the polarization element C3, and after being polarization-modulated by the polarization element C3, it exits in the same polarization direction as the polarization element C3 to form the third-time-sequence polarized light; finally, the light ray B4 enters the polarization element C4, and after being polarization-modulated by the polarization element C4, it exits in the same polarization direction as the polarization element C4 to form the fourth-time-sequence polarized light.

[0061] Of course, in other possible examples, the number of the light-emitting surfaces 210 and the polarization elements 401 can also be other numbers, and the present application does not make specific limitations on them.

[0062] In some possible implementation manners, the included angle between the polarization directions of any two polarization elements 401 is greater than 10 degrees, so that it is convenient to obtain polarization information by comprehensively analyzing the images formed by the polarized lights of each time sequence. As Figure 2 shown, the polarization directions of the polarization element C1 and the polarization element C2 have an included angle θ1, and the polarization directions of the polarization element C2 and the polarization element C4 have an included angle θ2, and both the included angle θ1 and the included angle θ2 are greater than 10 degrees. For example, in Figure 2 the example shown, assuming that the polarization direction of the polarization element C1 is 0 degree, then the polarization direction of the polarization element C2 is 45 degrees, the polarization direction of the polarization element C3 is 90 degrees, and the polarization direction of the polarization element C4 is 135 degrees. Therefore, the included angle θ1 is 45 degrees, and the included angle θ2 is 90 degrees. Of course, it is not limited thereto.

[0063] In some possible embodiments, the polarization device 400 including a plurality of polarization elements 401 may be integrally packaged with the light source 200, whereby the two can form an integral unit. Of course, the polarization device 400 may also be separately provided from the light source 200.

[0064] In another possible example: Please refer to Figure 4 , in the optical path, the first linear polarizer 410 and the liquid crystal phase retarder 420 included in the polarization device 400 are respectively shown. Among them, the first linear polarizer 410 and the liquid crystal phase retarder 420 are located on the light-emitting side of the light source 200, and the first linear polarizer 410 is located between the light source 200 and the liquid crystal phase retarder 420. The first linear polarizer 410 can modulate the incident light into linearly polarized light, so that it is convenient for the collected light 300 to be modulated by the first linear polarizer 410 and then enter the liquid crystal phase retarder 420 in the form of linearly polarized light. The liquid crystal phase retarder 420 can change the polarization direction of the incident linearly polarized light. When it is necessary to form a plurality of sequential polarized lights in chronological order, the voltage on both sides of the liquid crystal can be sequentially changed in chronological order, so that the deflection angle of the liquid crystal changes sequentially in chronological order. Thus, a plurality of sequential polarized lights will be sequentially emitted from the liquid crystal phase retarder 420 in chronological order, and the polarization directions of any two sequential polarized lights are different. Such a plurality of sequential polarized lights with chronological order will be incident on the human face 100 in chronological order, and after being reflected by the human face 100 in chronological order, each sequential polarized light will carry polarization information corresponding to the contour of the human face 100, and then continue to be received and imaged by the photosensitive unit 500 in chronological order, so as to more accurately reconstruct the contour surface of the human face 100.

[0065] In some possible embodiments, any one or all of the first linear polarizer 410 and the liquid crystal phase retarder 420 may be integrally packaged with the light source 200 to form an integral unit. Alternatively, any one or all of the first linear polarizer 410 and the liquid crystal phase retarder 420 may also be separated from the light source 200 and set separately.

[0066] In yet another possible example: Please refer to Figure 5 , in the optical path, the first linear polarizer 440 included in the polarization device 400 and the driver 430 located outside the optical path are shown. Among them, the first linear polarizer 440 is located on the light-emitting side of the light source 200, and the first linear polarizer 440 and the driver 430 are drivingly connected. The present application does not limit the transmission form between the two. For example, they can be connected by forms such as gears, worm gears, etc. And please refer to Figure 6 , the driver 430 can drive the first linear polarizer 440 to rotate around the optical axis a of the light source 200 in the clockwise or counterclockwise direction.

[0067] When it is necessary to form multiple time-sequential polarized lights in chronological order, the first polarizer 440 can be driven by the driver 430 to rotate around the optical axis a of the light source 200. During the rotation of the first polarizer 440, the polarization direction thereon also gradually changes with time. Therefore, when the acquisition light 300 emitted by the light source 200 continuously or intermittently enters the first polarizer 440, due to the different rotation angles of the first polarizer 440 at different times, the incident acquisition light 300 will be modulated by the first polarizer 440 into multiple time-sequential polarized lights with a chronological order, and the polarization directions of any two time-sequential polarized lights are different. In this way, the multiple time-sequential polarized lights with a chronological order will sequentially enter the human face 100 in chronological order, and after being reflected by the human face 100 in chronological order, each time-sequential polarized light will carry the polarization information corresponding to the contour surface of the human face 100, and then continue to be received and imaged by the photosensitive unit 500 in chronological order, so as to more accurately reconstruct the contour surface of the human face 100.

[0068] In some possible examples, such as Figure 1 、 Figures 3 to 5 shown, a second polarizer 600 is further provided between the target object and the photosensitive unit 500, and the second polarizer 600 is located on the photosensitive side of the photosensitive unit 500. In this way, after the multiple time-sequential polarized lights are reflected by the human face 100, they first pass through the second polarizer 600, and then enter the photosensitive unit 500. By providing the second polarizer 600, it is convenient for the photosensitive unit 500 to determine the polarization information of the time-sequential polarized lights by sensing the brightness of the images formed by each time-sequential polarized light.

[0069] In some possible examples, such as Figure 1 、 Figures 3 to 5 shown, the polarization direction of the second polarizer 600 is the same as the polarization direction of one of the multiple time-sequential polarized lights. In this way, more light can smoothly enter the photosensitive unit 500 through the second polarizer 600, thereby providing more signal light for the photosensitive unit 500 and helping to improve the recognition accuracy. For example, in combination with Figures 1 to 3 it can be known that the polarization direction of the second polarizer 600 is the same as the polarization direction of the polarization element 401. For example, in Figure 4 , the polarization direction of the second polarizer 600 is the same as the polarization direction of the time-sequential polarized light emitted from the liquid crystal phase retarder at a certain moment. Another example is that in Figure 5 , the polarization direction of the second polarizer 600 is the same as the polarization direction of the light modulated by the first polarizer 440 at a certain moment.

[0070] In some possible examples, the photosensitive unit 500 can be formed by a plurality of photosensitive units in a two-dimensional array, and the light-receiving surfaces on the same side of the plurality of photosensitive units are combined to form the photosensitive surface of the photosensitive unit 500.

[0071] As Figure 1 , Figures 3 to 5 shown in the three-dimensional imaging device, when a second linear polarizer 600 is further provided between the object and the photosensitive unit 500, the setting form of the second linear polarizer 600 may include but is not limited to:

[0072] Form 1: The second linear polarizer 600 can be separately provided separately from the photosensitive unit 500.

[0073] Form 2: The photosensitive unit 500 forms an image sensor through separate packaging or packaging with other layers (such as a pixel circuit, a microlens array, etc.), and the second linear polarizer 600 is attached to the photosensitive surface of the image sensor.

[0074] Form 3: After the photosensitive unit 500 forms an image sensor through separate packaging or packaging with other layers (such as a pixel circuit, a microlens array, etc.), an imaging lens is provided on the photosensitive side of the image sensor. Among them, the second linear polarizer 600 can be located between the image sensor and the imaging lens (specifically: the second linear polarizer 600 can be separately provided from the image sensor and the imaging lens, or the second linear polarizer 600 can be attached to the light-emitting surface 210 of the imaging lens). Of course, the second linear polarizer 600 can also be located on the side of the imaging lens facing away from the image sensor (specifically: the second linear polarizer 600 can be separately provided from the imaging lens, or the second linear polarizer 600 can be attached to the light-incident surface of the imaging lens).

[0075] Form 4: The second linear polarizer 600 is integrated into the image sensor. Specifically, the second linear polarizer 600 and the photosensitive unit 500 are integrated and packaged together as an image sensor. For example, the packaging layer can be at least the photosensitive unit 500, the pixel circuit (pixel light-shielding layer), and the second linear polarizer 600 stacked in sequence, and for another example, the packaging layer can at least also be the pixel circuit, the photosensitive unit 500, and the second linear polarizer 600. In addition, a microlens array can be further provided in the image sensor above the second linear polarizer 600.

[0076] Please refer to Figure 7, a three-dimensional imaging device is shown in which a polarization device 400 is located between a target object and a photosensitive unit 500. When it is necessary to reconstruct the contour surface of the human face 100, the acquisition light 300 is emitted from the light source 200 towards the human face 100. The acquisition light 300 first enters the human face 100, and then after being reflected by the human face 100, it enters the polarization device 400. The polarization device 400 performs polarization modulation on the acquisition light 300 in chronological order, thereby forming a plurality of chronological polarization lights, and any two chronological polarization lights still satisfy that the polarization directions are different from each other. In this way, each chronological polarization light will carry the polarization information corresponding to the contour surface of the human face 100, and then it is received and imaged by the photosensitive unit 500 in chronological order, thereby reconstructing the contour surface of the human face 100 more accurately.

[0077] For a three-dimensional imaging device in which the polarization device 400 is located between a target object and a photosensitive unit 500, when forming a plurality of chronological polarization lights, it may include but is not limited to the following examples:

[0078] In one possible example: Please refer to Figure 8 , in the optical path, the first polarizer 450 and the liquid crystal phase retarder 460 included in the polarization device 400 are respectively shown. Among them, the first polarizer 450 and the liquid crystal phase retarder 460 are located on the photosensitive side of the photosensitive unit 500, and the liquid crystal phase retarder 460 is located between the first polarizer 450 and the photosensitive unit 500. The first polarizer 450 can modulate the incident light into linearly polarized light, so that it is convenient for the acquisition light 300 to enter the liquid crystal phase retarder 460 in the form of linearly polarized light after being modulated by the first polarizer 450. The liquid crystal phase retarder 460 can change the polarization direction of the incident linearly polarized light. When it is necessary to form a plurality of chronological polarization lights in chronological order, the voltage on both sides of the liquid crystal can be changed successively in chronological order, so that the deflection angle of the liquid crystal changes successively in chronological order. Thus, a plurality of chronological polarization lights will be emitted from the liquid crystal phase retarder 460 in chronological order, and the polarization directions of any two chronological polarization lights are different. In this way, each chronological polarization light will carry the polarization information corresponding to the contour surface of the human face 100, and then it is received and imaged by the photosensitive unit 500 in chronological order, thereby reconstructing the contour surface of the human face 100 more accurately.

[0079] In another possible example: Please refer to Figure 9, a first linear polarizer 480 included in the polarization device 400 and a driver 470 located outside the optical path are shown in the optical path. Among them, the first linear polarizer 480 is located on the photosensitive side of the photosensitive unit 500, and the first linear polarizer 480 and the driver 470 are drivingly connected. The present application does not limit the transmission form between the two. For example, they can be connected through forms such as gears, worm gears, etc. And the driver 470 can drive the first linear polarizer 480 to rotate around the optical axis of the light source 200 in the clockwise or counterclockwise direction.

[0080] When it is necessary to form multiple sequential polarized lights in chronological order, the driver 470 can drive the first linear polarizer 480 to rotate around the optical axis of the light source 200. During the rotation of the first linear polarizer 480, the polarization direction thereon also gradually changes with time. Therefore, when the collected light 300 reflected by the human face 100 is incident on the first linear polarizer 480, due to the different rotation angles of the first linear polarizer 480 at different times, the incident collected light 300 will be modulated by the first linear polarizer 480 into multiple sequential polarized lights with chronological order, and the polarization directions of any two sequential polarized lights are different. In this way, each sequential polarized light will carry the polarization information corresponding to the contour surface of the human face 100, and then be received and imaged by the photosensitive unit 500 in chronological order, so as to more accurately reconstruct the contour surface of the human face 100.

[0081] In some possible examples, as Figures 7 to 9 shown, a second linear polarizer 600 is further provided between the target object and the light source 200, and the second linear polarizer 600 is located on the light-emitting side of the light source 200. In this way, the collected light 300 emitted by the light source 200 can first pass through the second linear polarizer 600, then be incident on the human face 100 and then be reflected by the human face 100 and incident on the polarization device 400. By setting the second linear polarizer 600, it is convenient to control the collected light 300 incident on the human face 100 to maintain a linearly polarized state, which is convenient for the subsequent photosensitive unit 500 to comprehensively analyze the images formed by each sequential polarized light to obtain polarization information.

[0082] In some possible examples, as Figures 7 to 9 shown, the polarization direction of the second linear polarizer 600 is the same as the polarization direction of one of the multiple sequential polarized lights. In this way, more light can be incident on the photosensitive unit 500 through the polarization device 400, so as to provide more signal light for the photosensitive unit 500, which helps to improve the recognition accuracy. For example Figure 8 in, the polarization direction of the second linear polarizer 600 is consistent with the polarization direction of the sequential polarized light emitted from the liquid crystal phase retarder at a certain moment. Another example is Figure 9 in, the polarization direction of the second linear polarizer 600 is consistent with the polarization direction of the light modulated by the first linear polarizer 480 at a certain moment.

[0083] In some possible examples, such as Figures 7 to 9 in the three-dimensional imaging device shown, when a second linear polarizer 600 is further provided between the object and the light source 200, the second linear polarizer 600 can be attached to the light-emitting surface 210 of the light source 200, or the second linear polarizer 600 can be separately provided separated from the light source 200.

[0084] In some possible examples, the photosensitive unit 500 can be formed by a plurality of photosensitive elements in a two-dimensional array, and the light-receiving surfaces on the same side of the plurality of photosensitive elements are combined to form the photosensitive surface of the photosensitive unit 500. Such as Figures 7 to 9 in the three-dimensional imaging device shown, the setting forms of the polarization device 400 can include but are not limited to:

[0085] Form 1: As Figure 8 shown, when the polarization device 400 includes a first linear polarizer 450 and a liquid crystal phase retarder 460, the first linear polarizer 450 and the liquid crystal phase retarder 460 can be separately provided separated from the photosensitive unit 500.

[0086] Form 2: As Figure 8 shown, when the polarization device 400 includes a first linear polarizer 450 and a liquid crystal phase retarder 460, the photosensitive unit 500 forms an image sensor through encapsulation, and the liquid crystal phase retarder 460 is attached to the photosensitive surface of the image sensor.

[0087] Form 3: As Figure 8 shown, when the polarization device 400 includes a first linear polarizer 450 and a liquid crystal phase retarder 460, after the photosensitive unit 500 forms an image sensor through encapsulation, an imaging lens is provided on the photosensitive side of the image sensor. Among them, the first linear polarizer 450 and the liquid crystal phase retarder 460 can be located between the image sensor and the imaging lens (specifically: the first linear polarizer 450 and the liquid crystal phase retarder 460 can be separately provided from the image sensor and the imaging lens, or the first linear polarizer 450 can be attached to the light-emitting surface 210 of the imaging lens). Of course, the first linear polarizer 450 and the liquid crystal phase retarder 460 can also be located on the side of the imaging lens away from the image sensor (specifically: the first linear polarizer 450 and the liquid crystal phase retarder 460 can be separately provided from the imaging lens, or the liquid crystal phase retarder 460 can be attached to the light-incident surface of the imaging lens). In addition, it can also be that the imaging lens is located between the first linear polarizer 450 and the liquid crystal phase retarder 460 (specifically: the first linear polarizer 450 and the liquid crystal phase retarder 460 can be separately provided from the imaging lens, or at least one of the first linear polarizer 450 and the liquid crystal phase retarder 460 can be attached to the surface of the imaging lens).

[0088] Form 4: As Figure 8As shown, when the polarization device 400 includes a first linear polarizer 450 and a liquid crystal phase retarder 460, the first linear polarizer 450 and the liquid crystal phase retarder 460 are integrally packaged with the photosensitive unit 500 as an image sensor. For example, the packaging levels can be at least the photosensitive unit 500, the pixel circuit (pixel light-shielding layer), the liquid crystal phase retarder 460, and the first linear polarizer 450 stacked in sequence. Or, for another example, the packaging levels can be at least the pixel circuit, the photosensitive unit 500, the liquid crystal phase retarder 460, and the first linear polarizer 450. In addition, a microlens array can be stacked above the first linear polarizer 450 in the image sensor.

[0089] Optionally, a filter is further provided on the photosensitive side of the photosensitive unit 500. The wavelength band of the collected light 300 is the target wavelength band. The filter is used to filter out the light outside the target wavelength band, so as to reduce the interference of stray light. As Figures 1 to 6 shown, the filter can be located between the second linear polarizer 600 and the photosensitive unit 500, or the filter can be located on the side of the second linear polarizer 600 away from the photosensitive unit 500; as Figures 7 to 9 shown, the filter can also be located between the polarization device 400 and the photosensitive unit 500, or the filter can be located on the side of the polarization device 400 away from the photosensitive unit 500. Or, when the polarization device 400 includes a first linear polarizer 450 and a liquid crystal phase retarder 460, the filter can also be located between the first linear polarizer 450 and the liquid crystal phase retarder 460.

[0090] Optionally, the light source 200 in this application can be an infrared light source 200 or a visible light source 200. Among them, the collected light 300 emitted by the infrared light source 200 is light in the infrared wavelength band, and the collected light 300 emitted by the visible light source 200 is light in the visible wavelength band. When the light source 200 is an infrared light source 200, used in combination with the filter, it can not only weaken the perception of the human eye, but also effectively reduce the interference of ambient light.

[0091] On the other hand, an embodiment of this application provides a three-dimensional imaging method, which can be applied to the foregoing three-dimensional imaging device, as Figure 10 shown, the method includes:

[0092] S10: Control the photosensitive unit to receive multiple time-sequential polarized lights in a preset time-sequential order and form multiple polarized images, where the polarization directions of any two time-sequential polarized lights are different.

[0093] S20: Obtain the polarization information corresponding to each pixel in the photosensitive unit according to the multiple polarized images.

[0094] S30: Obtain the normal vector information of each micro - element in the target object according to the polarization information corresponding to each pixel in the photosensitive unit and the preset mapping relationship between each pixel in the photosensitive unit and each micro - element in the target object.

[0095] S40: Obtain the three - dimensional contour information of the target object according to the normal vector information of each micro - element in the target object and the position information of each pixel.

[0096] The photosensitive unit 500 sequentially receives each timing polarized light in chronological order to generate multiple polarized images. By utilizing the characteristic that the degree of change in the polarization state of light for each point in the target object is different, the polarization information can be obtained through comprehensive analysis of multiple polarized images. Specifically, the polarized images are mapped to each pixel of the photosensitive unit 500, and in this way, the polarization information corresponding to each pixel is obtained by comprehensively analyzing the brightness information of the same pixel in multiple polarized images.

[0097] Since the light received by each pixel comes from different positions on the surface of the target object, the normal vector information of each micro - element in the target object is obtained through the preset mapping relationship between each pixel in the photosensitive unit 500 and each micro - element (different positions in the target object). In this way, the three - dimensional contour information of the target object can be obtained according to the normal vector information of each micro - element in the target object and the position information of each pixel, and the contour surface of the target object can be reconstructed accordingly.

[0098] On the other hand, an embodiment of the present application provides a face recognition method, and the method includes:

[0099] S60: Control the photosensitive unit to receive multiple timing polarized lights in a preset timing sequence and form multiple polarized images. Among them, the acquisition light emitted by the light source is reflected by the target object and then incident on the photosensitive unit, and before the acquisition light is incident on the photosensitive unit, it is time - division polarization - modulated by a polarization device to form multiple timing polarized lights with different polarization directions, and the pixel values of the polarized images contain polarization information corresponding to the contour surface of the target object.

[0100] Since the acquisition light has been time - division polarization - modulated by the polarization device into multiple timing polarized lights before being received by the photosensitive unit, the photosensitive unit 500 can sequentially receive each timing polarized light in chronological order to generate multiple polarized images. By utilizing the characteristic that the degree of change in the polarization state of light for each point in the human face (i.e., the target object) is different, the pixel values in each polarized image will contain the polarization information to which they belong, and each polarization information corresponds to the contour surface of the human face. In other words, the contour surface of the corresponding human face can be characterized by multiple polarized images.

[0101] S70: Perform face recognition based on multiple polarized images and obtain a face recognition result. Face recognition includes: face matching and / or anti - counterfeiting recognition.

[0102] Since multiple polarized images can characterize the corresponding face contour surface, face recognition can be performed through multiple polarized images, and then a face recognition result can be obtained. Among them, when performing face recognition based on multiple polarized images, it can specifically be the verification of face matching and / or the verification of anti-counterfeiting recognition. When the face recognition includes the verification of face matching, the face recognition result correspondingly includes the result of whether the faces match. Similarly, when the face recognition includes the verification of anti-counterfeiting recognition, the face recognition result also correspondingly includes the result of whether it is a real face or a forgery such as a photo, video, or face silicone mold.

[0103] When performing the verification of face matching, multiple polarized images and a database image can be input into the first neural network model to obtain the result of whether the faces match.

[0104] When performing the verification of anti-counterfeiting recognition, multiple polarized images can be input into the second neural network model to obtain the anti-counterfeiting result of whether it is a real face or a forgery such as a photo, video, or face silicone mold.

[0105] The database image is an image stored in advance, and this image characterizes correct face information.

[0106] In addition, when performing face recognition, the three-dimensional contour information of the face can also be obtained from multiple polarized images through the aforementioned three-dimensional imaging method, and then the face recognition result can be finally obtained through the three-dimensional contour information. Of course, in this face recognition method, the verification of face matching and / or the verification of anti-counterfeiting recognition can still be included.

[0107] Another aspect of the embodiments of the present application provides an electronic device, including a device main body and any one of the above three-dimensional imaging devices, and the three-dimensional imaging device is located in the device main body. Through the aforementioned three-dimensional imaging device, the information of the target object can be better collected, and the contour surface of the target object can be reconstructed in cooperation with the controller in the device main body, which helps to improve the recognition accuracy.

[0108] Of course, the aforementioned face recognition method can be applied to this electronic device.

[0109] The electronic device can specifically be a mobile phone, a tablet computer, a television, a laptop computer, a smart home device (such as a smart air conditioner, a smart refrigerator, a smart speaker, a smart light, or a smart curtain, etc.), a wearable electronic device, a vehicle-mounted device (also called a car computer), a virtual reality device, etc., and the embodiments of the present application do not make any restrictions on this.

[0110] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A three-dimensional imaging device, characterized in that: It includes a light source, a polarization device and an image sensor arranged in sequence along the optical path, the image sensor includes a photosensitive unit, the collection light emitted by the light source is reflected by the target object and then incident on the photosensitive unit, and before the collection light is incident on the photosensitive unit, it is time-division polarization modulated by the polarization device to form a plurality of sequential polarized lights with different polarization directions, and the plurality of sequential polarized lights each carry polarization information corresponding to the contour surface of the target object and sequentially incident on the photosensitive unit.

2. The three-dimensional imaging device according to claim 1, characterized in that: The polarization device is located between the light source and the target object. The collected light emitted by the light source is time-divided and polarized by the polarization device to form a plurality of time-sequential polarized lights. After the plurality of time-sequential polarized lights are sequentially reflected by the target object, each carrying polarization information corresponding to the contour surface of the target object sequentially enters the photosensitive unit.

3. The three-dimensional imaging device according to claim 2, characterized in that: The light source has multiple light emitting surfaces, and the polarization device includes multiple polarization elements corresponding to the multiple light emitting surfaces one by one, each polarization element is located at the light emitting side corresponding to the light emitting surface, and among the multiple polarization elements, the polarization directions of any two polarization elements are different.

4. The three-dimensional imaging device according to claim 3, characterized in that: The included angle between the polarization directions of any two of the polarization elements is greater than 10 degrees.

5. The three-dimensional imaging device according to claim 2, characterized in that: The polarization device includes a first linear polarizer and a liquid crystal phase retarder located at the light emitting side of the light source, and the first linear polarizer is located between the light source and the liquid crystal phase retarder.

6. The three-dimensional imaging device according to claim 2, characterized in that: The polarization device comprises a first linear polarizer and a driver which are connected in driving manner, wherein the first linear polarizer is located at the light emitting side of the light source, and the driver is used for driving the first linear polarizer to rotate around the optical axis of the light source.

7. The three-dimensional imaging device according to any one of claims 2 to 6, characterized in that: A second linear polarizer is also arranged between the target object and the photosensitive unit.

8. The three-dimensional imaging device according to claim 7, characterized in that: The second linear polarizer is attached to the photosensitive surface of the image sensor; or the second linear polarizer is integrated into the image sensor.

9. The three-dimensional imaging device according to claim 7, characterized in that: The polarization direction of the second linear polarizer is the same as the polarization direction of one of the plurality of sequential polarized lights.

10. The three-dimensional imaging device according to claim 1, characterized in that: The polarization device is located between the target object and the photosensitive unit. The collection light emitted by the light source assembly is reflected by the target object and then time-dividedly polarized and modulated by the polarization device to form a plurality of sequential polarized lights. Each of the plurality of sequential polarized lights carries polarization information corresponding to the contour surface of the target object and sequentially enters the photosensitive unit.

11. The three-dimensional imaging device according to claim 10, characterized in that: The polarization device includes a first linear polarizer and a liquid crystal phase retarder located on the photosensitive side of the photosensitive unit, and the liquid crystal phase retarder is located between the first linear polarizer and the photosensitive unit.

12. The three-dimensional imaging device according to claim 10, characterized in that: The polarization device comprises a first linear polarizer and a driver which are connected in driving manner, wherein the first linear polarizer is located at the photosensitive side of the photosensitive unit, and the driver is used for driving the first linear polarizer to rotate around the optical axis of the photosensitive unit.

13. The three-dimensional imaging device according to any one of claims 10 to 12, characterized in that: A second linear polarizer is also arranged between the light source and the target object.

14. The three-dimensional imaging device according to claim 13, characterized in that: The polarization direction of the second linear polarizer is the same as the polarization direction of one of the plurality of sequential polarized lights.

15. An electronic device, characterized in that: It comprises an equipment body and a three-dimensional imaging device as claimed in any one of claims 1 to 14, wherein the three-dimensional imaging device is located in the equipment body.

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