Image acquisition device, electronic equipment and face recognition method

Abstract

The invention provides an image acquisition device, electronic equipment and a face recognition method, and relates to the technical field of biological recognition, the image acquisition device comprises a light source group and an image sensor which are sequentially arranged along a light path, the light source group comprises two light sources used for emitting polarized light, the polarization degrees of the polarized light emitted by the two light sources are not equal to 0, and the image sensor is arranged on the light source group. Polarization directions of the polarized light emitted by the two light sources are different, and the polarized light emitted by the two light sources is reflected by the target object and then respectively carries polarization information corresponding to the contour surface of the target object to sequentially enter the image sensor. According to the image acquisition device, the scheme of simplifying three-dimensional imaging is adopted, so that the image acquisition device can accurately reconstruct the face contour with a relatively simple scheme and relatively low cost, and the recognition precision is improved.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of the application with the application number 2024112594822 and the title "An Image Acquisition Device, an Electronic Device, and a Face Recognition Method" filed with the China National Patent Office on September 9, 2024, and the priority of the application with the application number 2024222080638 and the title "An Image Acquisition Device and an Electronic Device" filed with the China National Patent Office on September 9, 2024. The entire contents of both are incorporated herein by reference. Technical field

[0003] This application relates to the field of biometric technologies. Specifically, it relates to an image acquisition device, an electronic device, and a face recognition method. Background art

[0004] 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 usage methods.

[0005] Currently, the main solutions for implementing face recognition include binocular vision solutions, time - of - flight solutions, structured light solutions, etc. Among them, for the binocular vision solution, since the reconstruction accuracy is proportional to the camera baseline length, its application range is relatively limited; the cost of time - of - flight cameras is relatively high, and they are limited by time resolution, so the accuracy of 3D imaging is not high; although the structured light solution has the advantage of high imaging accuracy, its response speed is slow, the frame rate is low, and as the imaging distance increases, the imaging accuracy decreases. Therefore, another polarization 3D imaging technology that can be used for face recognition has also been gradually developed. However, currently, the implementation of polarization 3D imaging technology usually has a relatively complex scheme, which also makes the cost remain high. Summary of the invention

[0006] The purpose of this application is to provide an image acquisition device, an electronic device, and a face recognition method for the deficiencies in the above - mentioned existing technologies.

[0007] To achieve the above - mentioned purpose, the technical solutions adopted in the embodiments of this application are as follows:

[0008] In one aspect of the embodiments of the present application, an image acquisition device is provided, which includes a light source group and an image sensor arranged in sequence along the optical path. The light source group includes two light sources for respectively emitting polarized light. The degrees of polarization of the polarized light emitted by the two light sources are both not equal to 0, and the polarization directions of the polarized light emitted by the two light sources are different. The polarized light emitted by the two light sources is reflected by the target object and then sequentially enters the image sensor while carrying the polarization information corresponding to the contour surface of the target object.

[0009] Optionally, at least one light source satisfies the following conditions:

[0010] The light source includes a light-emitting element for emitting the polarized light emitted by the light source;

[0011] Or, the light source includes a light-emitting element and a polarizing element, and the light emitted by the light-emitting element is modulated by the polarizing element to form the polarized light emitted by the light source.

[0012] Optionally, the light-emitting element is a laser, and a diffusion element is further arranged on the light-emitting side of the laser for expanding the light-emitting angle of the laser.

[0013] Optionally, when the light source includes a light-emitting element and a polarizing element, and the light-emitting element is a laser, the polarizing element is located between the laser and the diffusion element.

[0014] Optionally, when the light source includes a light-emitting element and a polarizing element, and the light-emitting element is a laser, the light source is a packaged light source. The packaged light source further includes a packaging carrier board and a support structure. The laser is fixed to the packaging carrier board, the support structure is fixed to the packaging carrier board and is located beside the laser. The polarizing element and the diffusion element are discrete components, and the polarizing element and the diffusion element are respectively fixed to the support structure, wherein the polarizing element is located between the laser and the diffusion element, or the diffusion element is located between the laser and the polarizing element.

[0015] Optionally, when the light source includes a light-emitting element and a polarizing element, and the light-emitting element is a laser, the light source is a packaged light source. The packaged light source further includes a substrate, a packaging carrier board and a support structure. The laser is fixed to the packaging carrier board, the support structure is fixed to the packaging carrier board and is located beside the laser. The polarizing element is a polarizing unit on one surface of the substrate, the diffusion element is a diffusion unit on the other surface of the substrate, and the substrate is fixed to the support structure, wherein the polarizing unit is located between the laser and the diffusion unit, or the diffusion unit is located between the laser and the polarizing unit.

[0016] Optionally, the degree of polarization of the polarized light emitted by at least one light source is greater than 0.1.

[0017] Optionally, the maximum polarization directions of the polarized light emitted by the two light sources are different.

[0018] Optionally, the emission wavelength bands of the two light sources are the same.

[0019] Optionally, the image acquisition device further includes a narrow-band pass filter, which is located on the light receiving side of the image sensor, and the pass band of the narrow-band pass filter covers the light emitting bands of the two light sources.

[0020] Optionally, the light emitting band of at least one light source is 940 nm, and the pass band of the narrow-band pass filter is 940 nm ± 10 nm.

[0021] Optionally, both light sources are located beside the image sensor.

[0022] Optionally, the two light sources are located on the same side or opposite sides of the image sensor.

[0023] Optionally, the image acquisition device further includes a polarization device, the image sensor includes a photosensitive unit array, and the polarization device is located on the light receiving side of the photosensitive unit array.

[0024] Optionally, the polarization directions of the polarized light emitted by the two light sources are perpendicular to each other, and the polarization direction of the polarization device is perpendicular to the polarization direction of the polarized light emitted by one of the two light sources.

[0025] Optionally, the polarization directions of the polarized light emitted by the two light sources are the vertical direction and the horizontal direction respectively, and the polarization direction of the polarization device is the vertical direction or the horizontal direction.

[0026] Optionally, the polarization directions of the polarized light emitted by the two light sources are the vertical direction (0-degree polarization) and the horizontal direction (90-degree polarization) respectively, and the polarization direction of the polarization device is the vertical direction (0-degree polarization) or the horizontal direction (90-degree polarization).

[0027] On the other hand, an embodiment of the present application provides an electronic device, including a device main body and the image acquisition device of any one of the above, and the image acquisition device is arranged on the device main body.

[0028] Optionally, the device main body includes a display screen, and the image acquisition device is located below the display screen.

[0029] On yet another aspect of the embodiment of the present application, a face recognition method is provided, which is applied to the aforementioned electronic device. The two light sources include a first light source and a second light source, and the method includes:

[0030] Controlling the second light source to turn off and the first light source to emit polarized light, and generating a first polarized image according to the polarized light incident on the image sensor;

[0031] Controlling the first light source to turn off and the second light source to emit polarized light, and generating a second polarized image according to the polarized light incident on the image sensor;

[0032] Perform face recognition based on the first polarization image and the second polarization image, and obtain a face recognition result. The face recognition includes: face matching and / or anti-counterfeiting recognition.

[0033] Optionally, the image acquisition device of the electronic device further includes a polarization device. The image sensor of the electronic device includes a photosensitive unit array, and the polarization device is located on the light receiving side of the photosensitive unit array; the polarization directions of the polarized light emitted by the first light source and the second light source are perpendicular to each other, and the polarization direction of the polarization device is perpendicular to the polarization direction of the polarized light emitted by the first light source.

[0034] Perform face recognition based on the first polarization image and the second polarization image, and obtain a face recognition result. The face recognition includes: face matching and / or anti-counterfeiting recognition includes:

[0035] Perform two-dimensional face matching verification based on the first polarization image, and obtain a two-dimensional face matching result.

[0036] If the two-dimensional face matching result fails, the face recognition fails. If the two-dimensional face matching result passes, perform anti-counterfeiting recognition based on the first polarization image and the second polarization image, and obtain an anti-counterfeiting recognition result.

[0037] The beneficial effects of this application include:

[0038] This application provides an image acquisition device, an electronic device, and a face recognition method. The image acquisition device includes a light source group and an image sensor arranged in sequence along the optical path. The light source group includes two light sources for respectively emitting polarized light. The polarization degrees of the polarized light emitted by the two light sources are not equal to 0, and the polarization directions of the polarized light emitted by the two light sources are different. The polarized light emitted by the two light sources is incident on the image sensor in sequence after being reflected by the target object and each carrying polarization information corresponding to the contour surface of the target object. The image acquisition device simplifies the three-dimensional imaging scheme, enabling the image acquisition device to accurately reconstruct the face contour with a relatively simple scheme and low cost, and improving the recognition accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of this application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of this application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0040] Figure 1 One of the structural schematic diagrams of an image acquisition device provided for an embodiment of this application;

[0041] Figure 2Schematic diagram of the change in the polarization state of the same polarized light beam on surfaces of different materials;

[0042] Figure 3 Schematic diagram of the change in the polarization state of the same polarized light beam with different incident angles on the same white paper;

[0043] Figure 4 Second schematic diagram of the structure of an image acquisition device provided by an embodiment of the present application;

[0044] Figure 5 Third schematic diagram of the structure of an image acquisition device provided by an embodiment of the present application;

[0045] Figure 6 Schematic diagram of the structure of a light source provided by an embodiment of the present application;

[0046] Figure 7 First schematic diagram of the structure of a packaged light source provided by an embodiment of the present application;

[0047] Figure 8 Second schematic diagram of the structure of a packaged light source provided by an embodiment of the present application;

[0048] Figure 9 Schematic diagram of the distribution of three image acquisition devices provided by an embodiment of the present application;

[0049] Figure 10 Fourth schematic diagram of the structure of an image acquisition device provided by an embodiment of the present application;

[0050] Figure 11 Schematic diagram of the structure of an electronic device provided by an embodiment of the present application.

[0051] Icons: 100 - human face; 200 - first light source; 210 - first light-emitting element; 220 - first polarizing element; 230 - diffusion element; 300 - second light source; 310 - second light-emitting element; 320 - second polarizing element; 400 - image sensor; 410 - photosensitive unit array; 420 - lens assembly; 500 - packaged light source; 510 - laser; 520 - packaging carrier board; 530 - support structure; 541 - diffusion unit; 542 - polarizing unit; 10 - image acquisition device; 21 - middle frame; 22 - display screen. Detailed implementation manners

[0052] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. 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.

[0053] 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 drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying 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 distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0054] In the description of this application, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "coupled" 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 circumstances.

[0055] It should be known that the target object in this application can be Figure 1 the human face 100 in, the local parts (such as cheeks, nose, eyes) in the human face 100. 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. When the target object changes, those skilled in the art should be able to clearly understand the changed solution with reference to the following examples.

[0056] Please refer to Figure 1 , which shows an image acquisition device that can emit polarized light towards the human face 100 and can receive the polarized light after it is reflected by the human face 100, so as to acquire human face image information for convenient use in face recognition.

[0057] Specifically, the image acquisition device includes a light source group and an image sensor 400 arranged in sequence along the optical path. The light source group includes two light sources, and the two light sources are used to emit polarized light respectively (for convenient distinction and description, they are hereinafter referred to as the first light source 200 and the second light source 300 respectively. Correspondingly, the first light source 200 emits the first polarized light, and the second light source 300 emits the second polarized light). Based on the setting of this light source group, the number of required light sources can be optimized, so that the image acquisition device only includes two light sources, which helps to simplify the image acquisition device and facilitate its miniaturization. At the same time, it is also convenient for the image acquisition device to form only two images according to the polarized light it receives, which can also simplify the number of images formed by the image acquisition device and reduce the data processing amount of the image acquisition device.

[0058] After the image acquisition device is optimized, it is also necessary to ensure the accuracy of the face image information it acquires. Therefore, the polarized light emitted by each of the two light sources satisfies the following conditions: the polarization degrees of the first polarized light and the second polarized light are both not equal to 0, and the polarization directions of the first polarized light and the second polarized light are different. This helps the image acquisition device to more accurately acquire face image information and facilitate accurate face recognition.

[0059] Specifically, first of all, it should be understood that polarized light has the following characteristics: when polarized light is transmitted to the surface of an object and reflected by the object, the polarization states of the light rays in the polarized light will change, and the change amount of the polarization states of the light rays is related to the material of the surface of the object where the light rays are incident and the incident angles (spatial positions) of the points on the contour surface of the object where the light rays are incident. For example Figure 2 shows a schematic diagram of the change in the polarization state of the same beam of polarized light on the surfaces of different materials. When the same beam of polarized light is perpendicularly incident on the surfaces of different materials, by rotating the analyzer 360 degrees to receive the reflected polarized light, it can be seen that different materials of the object surface result in different corresponding changes in the polarization state; and for another example Figure 3 shows a schematic diagram of the change in the polarization state of the same beam of polarized light with different incident angles on the same white paper. When the same beam of polarized light is incident on the surface of the same white paper at different incident angles, by rotating the analyzer 360 degrees to receive the reflected polarized light, it can be seen that different incident angles result in different corresponding changes in the polarization state.

[0060] Back to Figure 1In the shown image acquisition device, the first light source 200 and the second light source 300 each emit polarized light with a polarization degree not equal to 0 towards the human face 100, facilitating the use of the characteristics of the aforementioned polarized light. Among them, based on the difference in the spatial positions of each point on the contour surface of the human face 100 (the incident angles of the polarized light rays at different points are different) and the surface material of the human face 100, the polarized light reflected by the human face 100 will carry polarization information corresponding to the contour surface of the target object. That is to say, the first polarized light will carry polarization information corresponding to the contour surface of the target object after being reflected by the human face 100, and the second polarized light will also carry polarization information corresponding to the contour surface of the target object after being reflected by the human face 100. And the two are incident on the image sensor 400 in sequence according to the time sequence, facilitating the image sensor 400 to generate two polarized images (i.e., human face image information) successively according to their incident order. In view of the different polarization directions of the first polarized light and the second polarized light, the information of the human face 100 in the depth direction can be obtained by analyzing the differences between the two polarized images. Based on this, the contour surface of the human face can be reconstructed more accurately, which helps to perform face recognition with higher accuracy.

[0061] It should be understood that the human face image information collected by the image acquisition device can be used to implement face recognition including face matching and / or anti-counterfeiting recognition. Among them, face matching refers to whether the face to be verified is the same person as the correct face pre-recorded in the database (usually judged by calculating the similarity). The correct face is also called a face template or a database image. Anti-counterfeiting recognition refers to whether the face to be verified is a real human face or a forgery such as a photo, a video, or a silicone mold of a human face.

[0062] Thus, the image acquisition device simplifies the three-dimensional imaging solution from both software and hardware aspects, enabling the image acquisition device to reconstruct the human face contour accurately with a relatively simple solution and at a lower cost, and improving the recognition accuracy.

[0063] When the first light source 200 and the second light source 300 emit polarized light, it can make the first polarized light and the second polarized light reach the human face 100 in sequence according to the time sequence and the two will not irradiate the human face 100 simultaneously, facilitating the separation of the first polarized light and the second polarized light in the time dimension, and facilitating the two polarized images formed by the image sensor 400 to correspond one by one to the first polarized light and the second polarized light respectively. For example, the first light source 200 first emits the first polarized light, and after a specific time delay, the first light source 200 is turned off, and then the second light source 300 emits the second polarized light; or, the first light source 200 and the second light source 300 are lit simultaneously but not turned off simultaneously. Among them, the optical paths of the first polarized light and the second polarized light transmitted to the human face 100 are different, which can also make the two separate in the time dimension and avoid the adverse situation caused by their mixing.

[0064] When two light sources of the light source group emit polarized light, multiple schemes can be adopted:

[0065] In some possible embodiments, the first light source 200 includes a light-emitting element (referred to as the first light-emitting element 210 for distinction from the second light source 300), and the first light-emitting element 210 is capable of directly emitting first polarized light. Alternatively, the first light source 200 includes the first light-emitting element 210 and a polarization element (referred to as the first polarization element 220 for distinction from the second light source 300), the first polarization element 220 is located on the light-emitting side of the first light-emitting element 210, and the light emitted by the first light-emitting element 210 is modulated by the first polarization element 220 to form first polarized light.

[0066] In some possible embodiments, the second light source 300 includes a light-emitting element (referred to as the second light-emitting element 310 for distinction from the first light source 200), and the second light-emitting element 310 is capable of directly emitting second polarized light. Alternatively, the second light source 300 includes the second light-emitting element 310 and a polarization element (referred to as the second polarization element 320 for distinction from the first light source 200), the second polarization element 320 is located on the light-emitting side of the second light-emitting element 310, and the light emitted by the second light-emitting element 310 is modulated by the second polarization element 320 to form second polarized light.

[0067] Thus, by combining the two respective schemes of the first light source 200 and the second light source 300, four different schemes can be formed. Two of them will be described below with reference to the accompanying drawings:

[0068] Scheme 1

[0069] Please refer to Figure 4 , the first light source 200 includes the first light-emitting element 210, and the first light-emitting element 210 is capable of directly emitting first polarized light. The second light source 300 includes the second light-emitting element 310, and the second light-emitting element 310 is capable of directly emitting second polarized light. If the degree of polarization of the polarized light emitted by the first light-emitting element 210 and / or the second light-emitting element 310 itself is greater than the target threshold (such as 0.1 or 0.2), no additional polarization element is required.

[0070] Scheme 2

[0071] Please refer to Figure 5, the first light source 200 includes a first light-emitting element 210 and a first polarizing element 220. The light (natural light or non-first polarized light) emitted by the first light-emitting element 210 is modulated by the first polarizing element 220 to form first polarized light. The second light source 300 includes a second light-emitting element 310 and a second polarizing element 320. The light (natural light or non-second polarized light) emitted by the second light-emitting element 310 is modulated by the second polarizing element 320 to form second polarized light. If the degree of polarization of the polarized light emitted by the first light-emitting element 210 and / or the second light-emitting element 310 itself is less than or equal to a target threshold (such as 0.1 or 0.2), an additional polarizing element is required to make the degree of polarization of the polarized light emitted by the light source greater than the target threshold.

[0072] In some possible implementation manners, the aforementioned first polarizing element 220 and / or the second polarizing element 320 is a polarizing sheet, such as a linear polarizing sheet, so that both the first polarized light and the second polarized light can be linear polarized light. In addition, when the first light-emitting element 210 included in the first light source 200 directly emits first polarized light, and / or, when the second light-emitting element 310 included in the second light source 300 directly emits second polarized light, both the first polarized light and the second polarized light can be linear polarized light.

[0073] In some possible implementation manners, the aforementioned first light-emitting element 210 and / or the second light-emitting element 310 includes, but is not limited to, an LED element, a laser, etc. Among them, the laser can be a Vertical-Cavity Surface-Emitting Laser (VCSEL), or an edge-emitting semiconductor laser, etc.

[0074] When the light-emitting types of the first light-emitting element 210 and / or the second light-emitting element 310 are different, their light-emitting characteristics are also different. For example, when the first light-emitting element 210 and / or the second light-emitting element 310 is a laser, considering that the laser has good directivity of light emission, its light-emitting angle is usually small. In order to make the light beam emitted by the light source group better cover the target object, a diffusion element 230, such as a diffusion plate, can be added on the light-emitting side of the laser, so that the diffusion element 230 expands the light-emitting angle of the laser.

[0075] When the first light source 200 includes a first light-emitting element 210 (a laser 510), a first polarization element 220, and a diffusion element 230, the first polarization element 220 can be disposed between the laser and the diffusion element 230, or the diffusion element 230 can be disposed between the laser and the first polarization element 220. Similarly, when the second light source 300 includes a second light-emitting element 310 (a laser), a second polarization element 320, and a diffusion element 230, the second polarization element 320 can be disposed between the laser and the diffusion element 230, or the diffusion element 230 can be disposed between the laser and the second polarization element 320.

[0076] Please refer to Figure 6 , when the first polarization element 220 has requirements for the incident angle of light, the laser, the first polarization element 220, and the diffusion element 230 can be arranged in sequence along the optical path, so that the light (with a small emission angle) emitted by the laser is first polarization-modulated by the first polarization element 220, and then diffused (to increase the emission angle) by the diffusion element 230, meeting the requirement that the incident angle of light on the first polarization element 220 cannot be too large. For example, when the first polarization element 220 is a metal grating, it requires that the incident angle of light cannot be too large, otherwise it will affect its modulation effect on the incident light. Therefore, the small-angle light emitted by the laser can be first modulated by the first polarization element 220 and then diffused by the diffusion element 230. Similarly, when the second polarization element 320 also has requirements for the incident angle of light, the laser, the second polarization element 320, and the diffusion element 230 can be arranged in sequence along the optical path.

[0077] The first light source 200 can be a packaged light source. For the structural form of the packaged light source, it can be various. For ease of understanding, the following two examples are schematically given in this application:

[0078] Example 1

[0079] When the first light source 200 includes a first light-emitting element 210 and other elements (the first polarization element 220 and / or the diffusion element 230), the first light source 200 can be a packaged light source. For example Figure 7As shown, the first light source 200 is a packaged light source 500. The packaged light source 500 includes a first light-emitting element 210 (being a laser 510), a first polarization element 220, a diffusion element 230, a packaging carrier 520, and a support structure 530. Among them, the laser 510 is fixed to the packaging carrier 520, the support structure 530 is fixed to the packaging carrier 520 and is located beside the laser 510. The first polarization element 220 and the diffusion element 230 are discrete components. The first polarization element 220 and the diffusion element 230 are respectively fixed to the support structure 530, and the first polarization element 220 is located between the laser 510 and the diffusion element 230. More specifically, the support structure 530 can be a multi-level stepped structure, and the stepped surface of each level can be fixed to the component. For example Figure 7 As shown, the support structure 530 includes at least two stepped surfaces. Among them, the first polarization element 220 is lapped and fixed to the stepped surface of one level, and the diffusion element 230 is lapped and fixed to the stepped surface of another level.

[0080] Of course, in some other embodiments where the first light source 200 is a packaged light source, the difference from the Figure 7 scheme shown is that the diffusion element 230 can also be located between the laser 510 and the first polarization element 220.

[0081] Example 2

[0082] When the first light source 200 includes the first light-emitting element 210 and other elements (the first polarization element 220 and / or the diffusion element 230), the first light source 200 can be a packaged light source. For example Figure 8 As shown, the first light source 200 is a packaged light source 500. The packaged light source 500 includes a first light-emitting element 210 (being a laser 510), a first polarization element 220, a diffusion element 230, a substrate, a packaging carrier 520, and a support structure 530. Among them, the first polarization element 220 is a polarization unit 542 on one surface of the substrate, and the diffusion element 230 is a diffusion unit 541 on the other surface of the substrate. Therefore, the first polarization element 220 and the diffusion element 230 are integrated components integrated on the same substrate, which helps to miniaturize the packaged light source 500. The laser 510 is fixed to the packaging carrier 520, the support structure 530 is fixed to the packaging carrier 520 and is located beside the laser 510. The substrate is fixed to the support structure 530, the diffusion unit 541 is located on the upper surface of the substrate, and the polarization unit 542 is located on the lower surface of the substrate, that is, a structure is formed where the first polarization element 220 is located between the laser 510 and the diffusion element 230. More specifically, the support structure 530 can be a multi-level stepped structure, and the stepped surface of each level can be fixed to the component. For example Figure 8 As shown, the support structure 530 includes at least one stepped surface. Among them, the substrate is lapped and fixed to the stepped surface of a certain level.

[0083] Of course, in some other embodiments where the first light source 200 is an encapsulated light source, the difference from the Figure 8 scheme shown is that the diffusion unit 541 and the polarization unit 542 can be swapped, that is, the diffusion unit 541 is located on the lower surface of the substrate and the polarization unit 542 is located on the upper surface of the substrate.

[0084] The second light source 300 can also be an encapsulated light source. For the structural form of this encapsulated light source, it can also be various. For more specific examples, reference can be made to the examples of the aforementioned first light source 200 for understanding. The difference between the two is that the encapsulated light source formed by the second light source 300 includes the second light-emitting element 310 and the second polarization element 320.

[0085] As mentioned above, the light beams emitted by the first light source 200 and the second light source 300 are polarized light. Therefore, the polarization degrees of the two light sources are not zero. Among them, the polarization degree of the polarized light can be represented by P, and P = (I max - I min ) / (I max + I min ), where I max is the luminous intensity of the polarized light in the maximum polarization direction, and I min is the luminous intensity of the polarized light in the minimum polarization direction. The polarized light in this formula can be the first polarized light emitted by the first light source 200 or the second polarized light emitted by the second light source 300.

[0086] Similarly as mentioned above, it is necessary to analyze the difference between two polarized images to obtain the information of the face 100 in the depth direction. Therefore, in order to facilitate the construction of the difference between the two polarized images, the maximum polarization directions of the light rays emitted by the aforementioned two light sources are different.

[0087] In some possible embodiments, the polarization degree of the polarized light emitted by the first light source 200 and / or the second light source 300 is greater than 0.1, so as to better improve the accuracy of acquisition and recognition.

[0088] Please refer to Figure 1 、 Figure 4 、 Figure 5 . When setting the positions of the light source and the image sensor 400, both light sources can be located beside the image sensor 400, so that the light source group and the image sensor 400 can be conveniently integrated into the same device body. When specifically setting, the following several examples can be adopted:

[0089] One of them: As shown in Figure 1 、 Figure 4 、 Figure 5 、 Figure 9 , in (a) or Figure 10As shown, the first light source 200 and the second light source 300 are located on opposite sides of the image sensor 400. More specifically, they can be the left and right opposite sides as shown in (a) of Figure 9 , or the upper and lower opposite sides.

[0090] Another case: As shown in (b) of Figure 9 , the first light source 200 and the second light source 300 are distributed on adjacent sides of the image sensor 400.

[0091] Yet another case: As shown in (c) of Figure 9 , the first light source 200 and the second light source 300 are distributed on the same side of the image sensor 400.

[0092] In some possible embodiments, the emission bands of the first light source 200 and the second light source 300 can be the same or different.

[0093] In some possible embodiments, the image acquisition device further includes a narrowband pass filter. The narrowband pass filter is located on the light receiving side of the image sensor 400, and the pass band of the narrowband pass filter covers the emission bands of the two light sources. That is to say, the first polarized light and the second polarized light can pass through the narrowband pass filter smoothly after being reflected by the human face 100, and then enter the image sensor 400. By setting the narrowband pass filter, stray light can be further filtered out to prevent interference light from entering the image sensor 400 and generating large noise.

[0094] In some possible embodiments, the first light source 200 and the second light source 300 can be infrared light sources, thereby reducing the sensitivity of the human eye. Correspondingly, the pass band of the narrowband pass filter should include the emission band of the infrared light source. For example, the emission band of the first light source 200 and / or the second light source 300 is 940 nm, and the pass band of the narrowband pass filter is 940 nm ± 10 nm. By using the two in combination, the interference stray light generated by sunlight can be effectively filtered out.

[0095] In some possible embodiments, an optical path guiding structure is further provided on the light receiving side of the image sensor 400, such as the lens assembly 420 (as shown in Figure 10 ) or the microlens array, which facilitates the modulation of the first polarized light and the second polarized light through the optical path guiding structure after being reflected by the human face 100, so as to improve the imaging quality. When the light receiving side of the image sensor 400 has both an optical path guiding structure and a narrowband pass filter, the narrowband pass filter can be located between the optical path guiding structure and the image sensor 400, or the optical path guiding structure can be located between the narrowband pass filter and the image sensor 400, or the narrowband pass filter can be disposed in the optical path guiding structure, such as Figure 10As shown, the optical path guiding structure is the lens assembly 420. The narrow-bandpass filter can be located on the light incident side or the light exiting side of the lens assembly 420, or the narrow-bandpass filter is located between multiple optical elements in the lens assembly 420.

[0096] In some possible implementation manners, the image acquisition device further includes a polarization device. The image sensor 400 includes a photosensitive unit array 410. The polarization device is located on the light receiving side of the photosensitive unit array 410. In this way, after the first polarized light and the second polarized light are reflected by the human face 100, they are first modulated into a single linearly polarized light by the polarization device, and then received and imaged by the photosensitive unit array 410. By using the characteristic that the degree of change in the polarization state of light at each point in the human face 100 is different, the polarization information carried by the light can be obtained by comprehensively analyzing each polarization image, and the degree of change in the polarization state of the light can be obtained by using the polarization information, and then the normal vector of the position in the human face 100 can be determined. Combining this with the positions of the receiving pixels in the photosensitive unit array 410, 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.

[0097] In some possible implementation manners, the polarization directions of the polarized light emitted by the two light sources can be perpendicular to each other, and the polarization direction of the polarization device can be perpendicular to the polarization direction of the polarized light emitted by one of the light sources and the same as the polarization direction of the polarized light emitted by the other light source.

[0098] For example: the polarization directions of the polarized light emitted by the two light sources are the vertical direction and the horizontal direction respectively, and the polarization direction of the polarization device is the vertical direction or the horizontal direction. For example, if the vertical polarization is defined as 0-degree polarization, then the horizontal polarization is 90-degree polarization. In terms of the polarization angle, this can make the difference between the polarized light emitted by the two light sources the largest.

[0099] On this basis, further cooperate with the polarization device to maximize the difference in the information (such as polarization information) contained in each of the two images when the photosensitive unit array receives the polarized light: when the polarization direction of the polarized light emitted by one of the light sources is the same as the polarization direction of the polarization device, the image obtained by the photosensitive unit array 410 contains the most information; when the polarization direction of the polarized light emitted by the other light source is perpendicular to the polarization direction of the polarization device, the image obtained by the photosensitive unit array 410 contains the least information. Then the information difference between the two polarization images obtained by the image sensor is the largest, which is beneficial to the recognition of the target object.

[0100] It should be understood here that there can be different implementation manners. For example, the polarization direction of the polarized light emitted by the first light source is the vertical direction, and the polarization direction of the polarized light emitted by the second light source is the horizontal direction. Or, the polarization direction of the polarized light emitted by the first light source is the horizontal direction, and the polarization direction of the polarized light emitted by the second light source is the vertical direction. On this basis, after combining the polarization device, the polarization direction of the polarization device can be the same as that of the first light source, or the polarization direction of the polarization device can be the same as that of the second light source.

[0101] On the other hand, an embodiment of the present application provides an electronic device, including a device body and the image acquisition device 10 of any one of the above. The image acquisition device 10 is disposed on the device body. Through the foregoing image acquisition device 10, information of the target object can be collected better, and the contour surface of the target object can be reconstructed in cooperation with the controller in the device body, which helps to improve the recognition accuracy.

[0102] The electronic device may 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 referred to as a car machine), a virtual reality device, etc. The embodiments of the present application do not make any restrictions on this.

[0103] For example Figure 11 As shown, a mobile phone is shown, which includes a device body and the foregoing image acquisition device 10. The device body includes a back plate, a middle frame 21, a main board, a battery, and a display screen 22. Among them, the back plate and the display screen 22 are respectively installed on opposite sides of the middle frame 21 so that the three enclose to form an internal space. The main board and the battery can be located in this internal space. The battery is used to supply power to the main board, the image acquisition device 10, and the display screen 22. An opening is provided on the display screen 22, and the position of the opening is aligned with the positions of the two light sources and the image sensor in the image acquisition device 10, so that the polarized light emitted by it can smoothly pass through the display screen 22 to propagate to the target object contour surface and receive the light reflected by the target object.

[0104] On yet another aspect, an embodiment of the present application provides a face recognition method, and the method includes:

[0105] S10: Control the second light source to turn off, and the first light source emits polarized light, and generate a first polarized image according to the polarized light incident on the image sensor;

[0106] S20: Control the first light source to turn off, and the second light source emits polarized light, and generate a second polarized image according to the polarized light incident on the image sensor;

[0107] S30: Perform face recognition based on the first polarization image and the second polarization image, and obtain the face recognition result. Face recognition includes: face matching and / or anti-counterfeiting recognition.

[0108] When the user enables the face recognition function, it is necessary to first input the correct face image information as the base image. During input, the first light source 200 and the second light source 300 each emit polarized light with a polarization degree not equal to 0 towards the correct face 100. The polarized light reflected by the correct face will carry the polarization information corresponding to the contour plane of the target object, and the two beams of polarized light are incident on the image sensor 400 in sequence according to time. In this way, the image sensor 400 can generate two base polarization images in sequence according to their incident order, thus forming the base image.

[0109] When the base image input is completed and the user needs to perform face recognition during normal use, the image acquisition device 10 is activated. The first light source 200 and the second light source 300 each emit polarized light with a polarization degree not equal to 0 towards the face to be verified, and after being reflected by the face to be verified, they are incident on the image sensor 400 in sequence according to time. In this way, the image sensor 400 can generate two polarization images in sequence according to their incident order (the polarization images at this time are to be verified, so they are called polarization images to be verified). By analyzing the two polarization images to be verified and the base image, the face recognition result can be obtained.

[0110] When the face recognition includes the verification of face matching, the face recognition result includes the result of whether the face matches (whether it passes). 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. It can be understood that there is no limit to the order of S10 and S20.

[0111] Optionally, S30 can be specifically: perform two-dimensional face matching verification based on the first polarization image formed first, and obtain the two-dimensional face matching result; if the two-dimensional face matching result is not passed, then the face recognition result is obtained as not matching. If the two-dimensional face matching result is passed, then the face recognition result is obtained as matching, and then anti-counterfeiting recognition is performed based on the first polarization image formed first and the second polarization image formed later.

[0112] Specifically, perform two-dimensional face matching verification based on the first polarization image formed first, and obtain the two-dimensional face matching result. In this way, when the two-dimensional face matching result is not passed, the face recognition result can be directly obtained as not matching, that is, the subsequent anti-counterfeiting recognition is terminated, which helps to save the data processing volume.

[0113] Further, if the two-dimensional face matching result is passed, it is concluded that the face recognition result is a match. A depth image to be verified is formed according to the code value difference at the same pixel position of the first polarization image formed first and the second polarization image formed later, and then the depth image to be verified is compared with the depth image in the database to perform anti-counterfeiting recognition. Among them, the depth image in the database is formed by the code value difference at the same pixel position of the two polarization images in the database formed for the correct face in the aforementioned input stage.

[0114] Optionally, the aforementioned face recognition method can be implemented based on a specific electronic device. For example, the electronic device includes a device body and an image acquisition device. The image acquisition device includes the aforementioned first light source, second light source, polarization device, and an image sensor having a photosensitive unit array 410. Among them, the polarization directions of the polarized light emitted by the first light source and the second light source are perpendicular to each other (which can be understood with reference to the aforementioned related description), and the polarization direction of the polarization device is perpendicular to the polarization direction of the polarized light emitted by the first light source.

[0115] Therefore, in S30, face recognition is performed based on the first polarization image and the second polarization image, and a face recognition result is obtained. Face recognition includes: face matching and / or anti-counterfeiting recognition includes:

[0116] S31: Perform two-dimensional face matching verification based on the first polarization image and obtain a two-dimensional face matching result.

[0117] S32: If the two-dimensional face matching result is not passed, the face recognition fails; if the two-dimensional face matching result is passed, anti-counterfeiting recognition is performed based on the first polarization image and the second polarization image, and an anti-counterfeiting recognition result is obtained.

[0118] Among them, if the anti-counterfeiting result is a real face, the face recognition is successful; if the anti-counterfeiting result is a forgery, the face recognition fails. S31 and S32 can be executed after S20, or S31 can be executed after S10. If the two-dimensional face matching result is passed, then S20 and S32 are executed; if the two-dimensional face matching result is not passed, then S20 is not executed.

[0119] The first polarization image is obtained by using the first light source, the polarization device, and the photosensitive unit array. At this time, since the polarization direction of the first light source is perpendicular to the polarization direction of the polarization device, the information contained in the first polarization image is the least. The second polarization image is obtained by using the second light source, the polarization device, and the photosensitive unit array. At this time, since the polarization direction of the second light source is the same as the polarization direction of the polarization device, the information contained in the second polarization image is the most, and the information difference between the two polarization images is the largest, which is beneficial to the recognition of the target object.

[0120] In this way, the first polarized image and the base library image can be used for image recognition, that is, two-dimensional face matching verification, and a two-dimensional face matching result can be obtained. The polarization direction of the first light source is perpendicular to the polarization direction of the polarization device, that is, the polarization direction of the light emitting end is perpendicular to the polarization direction of the light receiving end, which can minimize the light spot problem caused by the attack material (i.e., counterfeit) or face reflection, and can ensure the clarity of the first polarized image, thereby facilitating face matching verification.

[0121] As described above, the two-dimensional face matching results include two results: pass and fail. Subsequent anti-counterfeiting identification can perform different actions based on the two-dimensional face matching results. For example, if the two-dimensional face matching result is fail, the face recognition will fail directly and no anti-counterfeiting identification will be performed; if the two-dimensional face matching result is pass, anti-counterfeiting identification will be performed based on the first polarization image and the second polarization image to obtain the anti-counterfeiting identification result.

[0122] Optionally, face matching and anti-counterfeiting recognition can also be performed simultaneously. For example, S30 can be specifically as follows: forming a depth image (depth image to be verified) based on the code value difference between the first polarization image and the second polarization image at the same pixel position, performing face recognition based on the depth image, and obtaining a face recognition result.

[0123] First, when recording the base image, the base depth image can be formed by the code value difference at the same pixel position of the two base polarization images formed for the correct face in the aforementioned recording stage.

[0124] Then, when performing face recognition, the depth image to be verified can be compared with the depth image in the base library, so that face matching and anti-counterfeiting recognition can be performed simultaneously.

[0125] Of course, the above-mentioned face recognition method can be applied to the aforementioned electronic devices.

[0126] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. 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. An image acquisition device, characterized in that, It includes a light source group and an image sensor arranged in sequence along the optical path. The light source group includes two light sources for respectively emitting polarized light. The degrees of polarization of the polarized light emitted by the two light sources are both not equal to 0, and the polarization directions of the polarized light emitted by the two light sources are different. The polarized light emitted by the two light sources is reflected by the target object and then sequentially enters the image sensor, each carrying polarization information corresponding to the contour surface of the target object.

2. The image acquisition device according to claim 1, characterized in that, At least one of the light sources satisfies the following conditions: The light source includes a light-emitting element for emitting the polarized light emitted by the light source; Or, the light source includes a light-emitting element and a polarization element, and the light emitted by the light-emitting element is modulated by the polarization element to form the polarized light emitted by the light source.

3. The image acquisition device according to claim 2, wherein The light-emitting element is a laser, and a diffusion element is further arranged on the light-emitting side of the laser for expanding the light-emitting angle of the laser.

4. The image acquisition device according to claim 3, characterized in that, When the light source includes a light-emitting element and a polarization element, and the light-emitting element is a laser, the polarization element is located between the laser and the diffusion element.

5. The image acquisition device according to claim 3, characterized in that, When the light source includes a light-emitting element and a polarization element, and the light-emitting element is a laser, the light source is a packaged light source. The packaged light source further includes a packaging carrier and a support structure. The laser is fixed to the packaging carrier, and the support structure is fixed to the packaging carrier and is located beside the laser. The polarization element and the diffusion element are discrete components, and the polarization element and the diffusion element are respectively fixed to the support structure, where the polarization element is located between the laser and the diffusion element, or the diffusion element is located between the laser and the polarization element.

6. The image acquisition device according to claim 3, wherein, When the light source includes a light-emitting element and a polarization element, and the light-emitting element is a laser, the light source is a packaged light source. The packaged light source further includes a substrate, a packaging carrier and a support structure. The laser is fixed to the packaging carrier, and the support structure is fixed to the packaging carrier and is located beside the laser. The polarization element is a polarization unit on one surface of the substrate, and the diffusion element is a diffusion unit on the other surface of the substrate. The substrate is fixed to the support structure, where the polarization unit is located between the laser and the diffusion unit, or the diffusion unit is located between the laser and the polarization unit.

7. The image acquisition device according to any one of claims 1 to 6, characterized in that, The degree of polarization of the polarized light emitted by at least one of the light sources is greater than 0.

1.

8. The image acquisition device according to any one of claims 1 to 6, characterized in that, The maximum polarization directions of the polarized light emitted by the two light sources are different.

9. The image acquisition device according to any one of claims 1 to 6, characterized in that, The emission wavelength bands of the two light sources are the same.

10. The image acquisition device according to any one of claims 1 to 3, characterized in that, The image acquisition device further includes a narrowband pass filter, which is located on the light-receiving side of the image sensor, and the passband of the narrowband pass filter covers the emission wavelength bands of the two light sources.

11. The image acquisition device according to claim 10, characterized in that, The emission wavelength band of at least one of the light sources is 940 nm, and the passband of the narrowband pass filter is 940 nm ± 10 nm.

12. The image acquisition device according to any one of claims 1 to 6, characterized in that, The two light sources are located on the same side or opposite sides of the image sensor.

13. The image acquisition device according to any one of claims 1 to 6, characterized in that, The image acquisition device further includes a polarization device, and the image sensor includes a photosensitive unit array. The polarization device is located on the light-receiving side of the photosensitive unit array.

14. The image acquisition device according to claim 13, wherein The polarization directions of the polarized light emitted by the two light sources are perpendicular to each other, and the polarization direction of the polarization device is perpendicular to the polarization direction of the polarized light emitted by one of the two light sources.

15. The image acquisition device according to claim 14, characterized in that, The polarization directions of the polarized light emitted by the two light sources are the vertical direction and the horizontal direction respectively, and the polarization direction of the polarization device is the vertical direction or the horizontal direction.

16. An electronic device, characterized in that, It includes a device main body and the image acquisition device according to any one of claims 1 to 15, and the image acquisition device is arranged on the device main body.

17. A face recognition method, characterized in that, Applied to the electronic device according to claim 16, the two light sources include a first light source and a second light source, and the method includes: Controlling the second light source to be turned off and the first light source to emit polarized light, and generating a first polarized image according to the polarized light incident on the image sensor; Controlling the first light source to be turned off and the second light source to emit polarized light, and generating a second polarized image according to the polarized light incident on the image sensor; Performing face recognition according to the first polarized image and the second polarized image, and obtaining a face recognition result, where the face recognition includes: face matching and / or anti-counterfeiting recognition.

18. The face recognition method according to claim 17, characterized in that, The image acquisition device of the electronic device further includes a polarization device, the image sensor of the electronic device includes a photosensitive unit array, and the polarization device is located on the light receiving side of the photosensitive unit array; the polarization directions of the polarized light emitted by the first light source and the second light source are perpendicular to each other, and the polarization direction of the polarization device is perpendicular to the polarization direction of the polarized light emitted by the first light source; Performing face recognition according to the first polarized image and the second polarized image, and obtaining a face recognition result, where the face recognition includes: face matching and / or anti-counterfeiting recognition includes: Performing two-dimensional face matching verification according to the first polarized image, and obtaining a two-dimensional face matching result; If the two-dimensional face matching result is not passed, the face recognition fails; if the two-dimensional face matching result is passed, anti-counterfeiting recognition is performed according to the first polarized image and the second polarized image, and an anti-counterfeiting recognition result is obtained.

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