Image acquisition device and electronic equipment

Abstract

The utility model provides an image acquisition device and electronic equipment, 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, and the polarization degrees of the polarized light emitted by the two light sources are not equal to 0; 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 priority to application number 2024112594822 filed with the China Patent Office on September 9, 2024 and entitled “An image acquisition device, electronic device and face recognition method”, and application number 2024222080638 filed with the China Patent Office on September 9, 2024 and entitled “An image acquisition device and electronic device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of biometric identification technology, and in particular to an image acquisition device and an electronic device. Background Art

[0004] With the development of portable devices, the application of biometric technology is becoming more extensive and in-depth. Taking electronic devices as an example, fingerprint recognition and facial recognition are increasingly used in device screen wake-up and identity authentication steps in various programs, improving device security and flexibility of use.

[0005] Currently, the main solutions for facial recognition include binocular vision, time-of-flight, and structured light. Binocular vision, however, has limited applicability due to its reconstruction accuracy being proportional to the camera baseline length. Time-of-flight cameras are relatively expensive and limited by their temporal resolution, resulting in low 3D imaging accuracy. While structured light offers the advantage of high imaging accuracy, it suffers from slow response speeds and low frame rates, and its accuracy decreases with increasing imaging distance. Consequently, polarization-based 3D imaging, another technology applicable to facial recognition, has also been gradually developed. However, its implementation is currently complex, resulting in high costs. Utility Model Content

[0006] The purpose of this application is to provide an image acquisition device and an electronic device to address the deficiencies in the above-mentioned prior art.

[0007] To achieve the above objectives, the technical solutions adopted in the embodiments of the present application are as follows:

[0008] According to one aspect of an embodiment of the present application, an image acquisition device is provided, comprising a light source group and an image sensor arranged sequentially along an optical path, wherein the light source group comprises two light sources for respectively emitting polarized light, wherein the polarization degrees 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, and after being reflected by a target object, the polarized light emitted by the two light sources each carries polarization information corresponding to the contour surface of the target object and sequentially enters the image sensor.

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

[0010] The light source includes a light emitting element, which is used to emit polarized light emitted by the light source;

[0011] Alternatively, 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 polarized light emitted by the light source.

[0012] Optionally, the light emitting element is a laser, and a diffusion element is further provided on the light emitting side of the laser, and the diffusion element is used to expand 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, and the packaged light source also includes a package carrier and a support structure, the laser is fixed to the package carrier, the support structure is fixed to the package carrier and is located next to the laser, the polarizing element and the diffusion element are separate parts, 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, and the packaged light source also includes a substrate, a package carrier and a supporting structure, the laser is fixed to the package carrier, the supporting structure is fixed to the package carrier and is located next to the laser, the polarizing element is a polarizing unit on the surface of one side of the substrate, the diffusion element is a diffusion unit on the surface of the other side of the substrate, and the substrate is fixed to the supporting 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 polarization degree 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 lights emitted by the two light sources are different.

[0018] Optionally, the two light sources have the same light-emitting wavelength band.

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

[0020] Optionally, the light emission band of the at least one light source is 940 nm, and the bandpass band of the narrow bandpass 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 lights 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 lights emitted by the two light sources are respectively vertical and horizontal, and the polarization direction of the polarization device is vertical or horizontal.

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

[0027] Another aspect of an embodiment of the present application provides an electronic device, including a device body and any one of the above-mentioned image acquisition devices, wherein the image acquisition device is disposed in the device body.

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

[0029] The beneficial effects of this application include:

[0030] The present application provides an image acquisition device and electronic device. The image acquisition device includes a light source group and an image sensor arranged sequentially along an optical path. The light source group includes two light sources for respectively emitting polarized light. The polarized light emitted by the two light sources has a degree of polarization that is not equal to 0 and has different polarization directions. After being reflected by a target object, the polarized light emitted by the two light sources each carries polarization information corresponding to the target's contour surface and sequentially enters the image sensor. By simplifying the three-dimensional imaging scheme, the image acquisition device can accurately reconstruct facial contours with a relatively simple scheme and at a low cost, thereby improving recognition accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to 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 therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is one of the structural schematic diagrams of an image acquisition device provided in an embodiment of the present application;

[0033] Figure 2 Schematic diagram of the change in polarization state of the same beam of polarized light on surfaces of different materials;

[0034] Figure 3 Schematic diagram of the change in polarization state of the same white paper to the same beam of polarized light at different incident angles;

[0035] Figure 4 This is a second structural diagram of an image acquisition device provided in an embodiment of the present application;

[0036] Figure 5 The third structural diagram of an image acquisition device provided in an embodiment of the present application;

[0037] Figure 6 A schematic structural diagram of a light source provided in an embodiment of the present application;

[0038] Figure 7 This is one of the structural schematic diagrams of a packaged light source provided in an embodiment of the present application;

[0039] Figure 8 This is a second structural diagram of a packaged light source provided in an embodiment of the present application;

[0040] Figure 9 A schematic diagram of the distribution of three image acquisition devices provided in an embodiment of the present application;

[0041] Figure 10 This is a fourth structural diagram of an image acquisition device provided in an embodiment of the present application;

[0042] Figure 11 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0043] Icons: 100-human face; 200-first light source; 210-first light-emitting element; 220-first polarizing element; 230-diffusing 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-package carrier; 530-support structure; 541-diffusing unit; 542-polarizing unit; 10-image acquisition device; 21-middle frame; 22-display screen. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. It should be noted that, in the absence of conflict, the various features in the embodiments of the present application can be combined with each other, and the combined embodiments are still within the scope of protection of the present application.

[0045] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0047] It should be understood that the target in this application can be Figure 1 The human face 100 and parts of the human face 100 (such as cheeks, nose, and eyes) are of course not limited to these, and may also be other three-dimensional objects, such as fingers, palms, etc. For ease of understanding, the following description will be taken as an example of the human face 100. When the target object changes, those skilled in the art should be able to clearly understand the changed solution by referring to the following examples.

[0048] Please refer to Figure 1 , shows an image acquisition device, which can emit polarized light toward the face 100, and can receive the polarized light after being reflected by the face 100, thereby acquiring facial image information for convenient use in face recognition.

[0049] Specifically, the image acquisition device includes a light source group and an image sensor 400, arranged sequentially along an optical path. The light source group includes two light sources, each configured to emit polarized light (hereinafter referred to as a first light source 200 and a second light source 300, respectively, for ease of description; the first light source 200 emits light of a first polarization, and the second light source 300 emits light of a second polarization). Based on this light source group arrangement, the number of required light sources can be optimized, so that the image acquisition device includes only two light sources. This helps simplify the image acquisition device and facilitates its miniaturization. It also facilitates the image acquisition device to generate only two images based on the polarized light it receives, thus simplifying the number of images generated by the image acquisition device and reducing the amount of data processing required by the image acquisition device.

[0050] After optimization, the image acquisition device must also ensure the accuracy of the facial image information it captures. Therefore, the polarized light emitted by the two light sources must meet the following conditions: the polarization degrees of both the first polarized light and the second polarized light are not equal to 0, and the first polarized light and the second polarized light have different polarization directions. This helps the image acquisition device more accurately capture facial image information, facilitating accurate facial recognition.

[0051] Specifically, it should be understood that polarized light has the following characteristics: when polarized light is transmitted to the surface of the target and reflected by the target, the polarization state of each light in the polarized light will change. The amount of change in the polarization state of each light is related to the surface material of the target on which each light is incident and the incident angle (spatial position) of each point on the contour surface of the target on which it is incident. For example, Figure 2 The figure shows the change of polarization state of the same beam of polarized light on different material surfaces. When the same beam of polarized light is vertically incident on different material surfaces, the polarizer is rotated 360 degrees to receive the reflected polarized light. It can be seen that the polarization state changes differently depending on the surface material of the target object. For example, Figure 3 The diagram shows the change in polarization state of the same white paper for the same beam of polarized light at different incident angles. When the same beam of polarized light is incident on the same white paper surface at different incident angles, the polarizer is rotated 360 degrees to receive the reflected polarized light. It can be seen that the polarization state changes differently depending on the incident angle.

[0052] Back to Figure 1In the image acquisition device shown, the first light source 200 and the second light source 300 each emit polarized light with a non-zero polarization degree toward the face 100, facilitating the utilization of the aforementioned characteristics of polarized light. Based on the differences in the spatial positions of points on the face 100's contour surface (the incident angles of polarized light at different points are different) and the surface material of the face 100, the polarized light reflected by the face 100 carries polarization information corresponding to the target object's contour surface. In other words, the first polarized light carries polarization information corresponding to the target object's contour surface after reflection from the face 100, and the second polarized light also carries polarization information corresponding to the target object's contour surface after reflection from the face 100. The two polarized light rays are incident on the image sensor 400 in a temporal sequence, facilitating the image sensor 400 to generate two polarization images (i.e., facial image information) based on the order of their incidence. Given the different polarization directions of the first and second polarized light rays, depth information of the face 100 can be obtained by analyzing the difference between the two polarization images. This allows for more accurate reconstruction of the facial contour surface, facilitating high-precision facial recognition.

[0053] It should be understood that the facial image information collected by the image acquisition device can be used to implement facial recognition including facial matching and / or anti-counterfeiting identification, wherein facial matching refers to whether the face to be verified and the correct face entered in advance in the database are the same person (generally judged by calculating the similarity), the correct face is also called a face template or database image, and anti-counterfeiting identification refers to whether the face to be verified is a real face or a forgery such as a photo, video, or facial silicone mold.

[0054] Therefore, the image acquisition device simplifies the three-dimensional imaging solution from the aspects of software and hardware, so that the image acquisition device can accurately reconstruct the facial contour with a relatively simple solution and lower cost, thereby improving the recognition accuracy.

[0055] When the first light source 200 and the second light source 300 emit polarized light, the first polarized light and the second polarized light can reach the face 100 in chronological order and will not illuminate the face 100 at the same time, facilitating the separation of the first polarized light and the second polarized light in the time dimension, and facilitating the one-to-one correspondence between the two polarization images formed by the image sensor 400 and 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 delay, the first light source 200 is turned off, and then the second light source 300 emits the second polarized light; for another example, the first light source 200 and the second light source 300 are turned on at the same time but not turned off at the same time, wherein the optical path of the first polarized light and the second polarized light to the face 100 is different, which can also separate the two polarized lights in the time dimension and avoid the mixing of the two lights causing recognition problems.

[0056] When the two light sources in the light source group emit polarized light, several solutions can be used:

[0057] In some possible embodiments, the first light source 200 includes a light-emitting element (referred to as the first light-emitting element 210 to distinguish it from the second light source 300), and the first light-emitting element 210 can directly emit light of the first polarization. Alternatively, the first light source 200 includes the first light-emitting element 210 and a polarizing element (referred to as the first polarizing element 220 to distinguish it from the second light source 300), and the first polarizing element 220 is located on the light-emitting side of the first light-emitting element 210. The light emitted by the first light-emitting element 210 is modulated by the first polarizing element 220 to form the first polarized light.

[0058] In some possible embodiments, the second light source 300 includes a light-emitting element (referred to as the second light-emitting element 310 to distinguish it from the first light source 200), and the second light-emitting element 310 can directly emit light of the second polarization. Alternatively, the second light source 300 includes the second light-emitting element 310 and a polarizing element (referred to as the second polarizing element 320 to distinguish it from the first light source 200), with the second polarizing element 320 located on the light-emitting side of the second light-emitting element 310. The light emitted by the second light-emitting element 310 is modulated by the second polarizing element 320 to form the second polarized light.

[0059] Thus, by combining the two solutions of the first light source 200 and the second light source 300, four different solutions can be formed, two of which will be described below with reference to the accompanying drawings:

[0060] Option 1

[0061] Please refer to Figure 4 The first light source 200 includes a first light-emitting element 210, which can directly emit light of the first polarization. The second light source 300 includes a second light-emitting element 310, which can directly emit light of the second polarization. If the polarization degree of the polarized light emitted by the first light-emitting element 210 and / or the second light-emitting element 310 is greater than a target threshold (e.g., 0.1 or 0.2), no additional polarizing element is required.

[0062] Option 2

[0063] Please refer to Figure 5The 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 (e.g., 0.1 or 0.2), an additional polarizing element is required to ensure that the degree of polarization of the polarized light emitted by the light source is greater than the target threshold.

[0064] In some possible embodiments, the first polarizing element 220 and / or the second polarizing element 320 are polarizers, such as linear polarizers, so that both the first polarized light and the second polarized light can be linearly polarized light. Furthermore, when the first light-emitting element 210 included in the first light source 200 directly emits the first polarized light, and / or the second light-emitting element 310 included in the second light source 300 directly emits the second polarized light, both the first polarized light and the second polarized light can be linearly polarized light.

[0065] In some possible embodiments, the aforementioned first light-emitting element 210 and / or second light-emitting element 310 include but are not limited to LED elements, lasers, etc., wherein the laser can be a vertical-cavity surface-emitting laser (VCSEL) or an edge-emitting semiconductor laser, etc.

[0066] 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 are lasers, since the laser has good directionality 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 can expand the light-emitting angle of the laser.

[0067] When the first light source 200 includes a first light-emitting element 210 (which is a laser 510), a first polarizing element 220, and a diffusion element 230, the first polarizing 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 polarizing element 220. Similarly, when the second light source 300 includes a second light-emitting element 310 (which is a laser), a second polarizing element 320, and a diffusion element 230, the second polarizing 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 polarizing element 320.

[0068] Please refer to Figure 6 When the first polarizing element 220 has requirements for the incident angle of light, the laser, the first polarizing element 220, and the diffusion element 230 can be arranged in sequence along the optical path. In this way, the light emitted by the laser (small emitting angle) is first polarized and modulated by the first polarizing element 220, and then diffused by the diffusion element 230 (expanding the emitting angle), meeting the requirement that the first polarizing element 220 cannot have too large an incident angle for light. For example, when the first polarizing 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 modulated by the first polarizing element 220 first, and then diffused by the diffusion element 230. Similarly, when the second polarizing element 320 also has requirements for the incident angle of light, the laser, the second polarizing element 320, and the diffusion element 230 can also be arranged in sequence along the optical path.

[0069] The first light source 200 may be a packaged light source. The structure of the packaged light source may be various. For ease of understanding, the present application schematically provides the following two examples:

[0070] Example 1

[0071] When the first light source 200 includes the first light emitting element 210 and other elements (the first polarizing element 220 and / or the diffusion element 230), the first light source 200 may be a packaged light source. Figure 7As shown, the first light source 200 is a packaged light source 500, which includes a first light-emitting element 210 (which is a laser 510), a first polarizing element 220, a diffusion element 230, a package carrier 520, and a support structure 530, wherein the laser 510 is fixed to the package carrier 520, the support structure 530 is fixed to the package carrier 520 and is located next to the laser 510, the first polarizing element 220 and the diffusion element 230 are separate parts, the first polarizing element 220 and the diffusion element 230 are respectively fixed to the support structure 530, and the first polarizing element 220 is located between the laser 510 and the diffusion element 230. More specifically, the support structure 530 can be a multi-step structure, and the step surface of each step can be fixed to the element, for example Figure 7 As shown, the support structure 530 includes at least two step surfaces, wherein the first polarizing element 220 is overlapped and fixed to the step surface of one step, and the diffusion element 230 is overlapped and fixed to the step surface of the other step.

[0072] Of course, in some other embodiments where the first light source 200 is a packaged light source, Figure 7 The difference of the illustrated solution is that the diffusion element 230 can also be located between the laser 510 and the first polarization element 220 .

[0073] Example 2

[0074] When the first light source 200 includes the first light emitting element 210 and other elements (the first polarizing element 220 and / or the diffusion element 230), the first light source 200 may be a packaged light source. Figure 8 As shown, the first light source 200 is a packaged light source 500, which includes a first light-emitting element 210 (a laser 510), a first polarizing element 220, a diffusion element 230, a substrate, a package carrier 520, and a support structure 530. The first polarizing element 220 is a polarizing 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 polarizing element 220 and the diffusion element 230 are integrated components integrated into the same substrate, which facilitates the miniaturization of the packaged light source 500. The laser 510 is fixed to the package carrier 520, the support structure 530 is fixed to the package carrier 520 and is located next to 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 polarizing unit 542 is located on the lower surface of the substrate, forming a structure in which the first polarizing element 220 is located between the laser 510 and the diffusion element 230. More specifically, the support structure 530 may be a multi-step structure, and the step surface of each step may be fixed to the component, such as Figure 8 As shown, the support structure 530 includes at least one step surface, wherein the substrate overlaps and is fixed to the step surface of a certain step.

[0075] Of course, in some other embodiments where the first light source 200 is a packaged light source, Figure 8 The difference of the solution shown is that the diffusion unit 541 and the polarization unit 542 can be swapped in order, 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.

[0076] The second light source 300 can also be a packaged light source. The structural form of the packaged light source can also be diverse. For more specific examples, you can refer to the example of the aforementioned first light source 200 for understanding. The difference between the two is that the packaged light source formed by the second light source 300 includes a second light-emitting element 310 and a second polarizing element 320.

[0077] As mentioned above, the light beams emitted by the first light source 200 and the second light source 300 are polarized light, so the polarization degrees of the two light sources are not zero. The polarization degree of the polarized light can be represented by P, and P=(I max -I min ) / (I max +I min ), I max is the luminous intensity of polarized light in the direction of maximum polarization, 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.

[0078] As mentioned above, it is necessary to obtain the depth information of the face 100 by analyzing the difference between the two polarization images. Therefore, in order to facilitate the construction of the difference between the two polarization images, the maximum polarization directions of the light emitted by the two light sources are different.

[0079] In some possible implementations, 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 collection and recognition.

[0080] 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. This makes it easy to integrate the light source group and the image sensor 400 into the same device body. In the specific setting, the following examples can be used:

[0081] One of them: Figure 1 、 Figure 4 、 Figure 5 、 Figure 9 (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 Figure 9 The left and right opposite sides shown in (a) may also be the upper and lower opposite sides.

[0082] Another one of them: Figure 9 As shown in FIG. 5( b ), the first light source 200 and the second light source 300 are distributed on adjacent sides of the image sensor 400 .

[0083] Another one of them: Figure 9 As shown in (c) , the first light source 200 and the second light source 300 are distributed on the same side of the image sensor 400 .

[0084] In some possible implementations, the light emitting wavelengths of the first light source 200 and the second light source 300 may be the same or different.

[0085] In some possible implementations, the image acquisition device further includes a narrow bandpass filter located on the light-receiving side of the image sensor 400. The narrow bandpass filter has a passband that covers the wavelengths of the two light sources. That is, after being reflected by the face 100, the first polarized light and the second polarized light can smoothly pass through the narrow bandpass filter and then enter the image sensor 400. The provision of the narrow bandpass filter further filters out stray light, preventing interfering light from entering the image sensor 400 and generating significant noise.

[0086] In some possible implementations, the first light source 200 and the second light source 300 may be infrared light sources, thereby reducing the sensitivity of the human eye. Accordingly, the narrow bandpass filter's passband should encompass the infrared light source's emission wavelength. For example, if the first light source 200 and / or the second light source 300 emits light at 940 nm, the narrow bandpass filter's passband should be 940 nm ± 10 nm. By combining these two, interfering stray light generated by sunlight can be effectively filtered out.

[0087] In some possible implementations, a light path guiding structure is further provided on the light receiving side of the image sensor 400, such as a lens assembly 420 (eg Figure 10 As shown) or a microlens array, it is convenient for the first polarized light and the second polarized light to be modulated by the light path guiding structure after being reflected by the face 100, so as to improve the imaging quality. When the light receiving side of the image sensor 400 has both a light path guiding structure and a narrow bandpass filter, the narrow bandpass filter can be located between the light path guiding structure and the image sensor 400, or the light path guiding structure can be located between the narrow bandpass filter and the image sensor 400, or the narrow bandpass filter can be set in the light path guiding structure, for example Figure 10As shown, the light path guiding structure is a lens assembly 420 , and the narrow bandpass filter can be located on the light incident side or the light exit side of the lens assembly 420 , or the narrow bandpass filter can be located between multiple optical elements in the lens assembly 420 .

[0088] In some possible embodiments, the image acquisition device further includes a polarization device, and 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 face 100, they are first modulated into a single linear polarized light by the polarization device, and then received by the photosensitive unit array 410 for imaging. By utilizing the fact that each point in the face 100 has a different degree of change in the polarization state of the light, 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 using the polarization information, and then the normal vector of the position in the face 100 can be determined. In combination with the position of each receiving pixel in the photosensitive unit array 410, the contour surface of the target object can be reconstructed more accurately, so that the reconstructed contour surface is closer to the actual contour surface of the target object.

[0089] In some possible embodiments, the polarization directions of the polarized light emitted by the two light sources may be perpendicular to each other, and the polarization direction of the polarizer may 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.

[0090] For example, if two light sources emit polarized light in vertical and horizontal directions, respectively, and the polarization device is polarized in either vertical or horizontal directions, then the polarization device is polarized in either vertical or horizontal directions. For example, if vertical polarization is defined as 0 degrees, then horizontal polarization is defined as 90 degrees. This maximizes the difference in polarization angle between the two light sources.

[0091] On this basis, in combination with the polarization device, the photosensitive unit array can maximize the difference in information (such as polarization information) contained in the two images in the process of receiving 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; and 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. In this way, the information difference between the two polarized images obtained by the image sensor is the largest, which is conducive to the identification of the target object.

[0092] It should be understood that various implementations are possible. For example, the polarization direction of the polarized light emitted by the first light source is vertical, while the polarization direction of the polarized light emitted by the second light source is horizontal. Another example is the polarization direction of the polarized light emitted by the first light source is horizontal, while the polarization direction of the polarized light emitted by the second light source is vertical. Based on this, after combining the polarizer, the polarization direction of the polarizer can be made the same as the polarization direction of the first light source, or the same as the polarization direction of the second light source.

[0093] Another aspect of the present application provides an electronic device including a device body and any of the aforementioned image acquisition devices 10, disposed within the device body. The image acquisition device 10 can better capture information about a target object and, in conjunction with a controller within the device body, reconstruct the target's contour surface, thereby improving recognition accuracy.

[0094] The electronic device can specifically be a mobile phone, a tablet computer, a television, a laptop computer, a smart home device (for example, 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 computer), a virtual reality device, etc. The embodiments of the present application do not impose any restrictions on this.

[0095] For example Figure 11 As shown, a mobile phone is shown, which includes a device body and the aforementioned image acquisition device 10. The device body includes a back panel, a middle frame 21, a main board, a battery, and a display screen 22. The back panel and the display screen 22 are respectively installed on opposite sides of the middle frame 21 so that the three are enclosed to form an internal space. The main board and the battery can be located in the internal space. The battery is used to power 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 pass through the display screen 22 smoothly so as to propagate to the contour surface of the target object and receive the light reflected by the target object.

[0096] In another aspect of the embodiments of the present application, a face recognition method is provided, the method comprising:

[0097] S10: 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;

[0098] S20: 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;

[0099] S30: Performing face recognition based on the first polarization image and the second polarization image, and obtaining a face recognition result. The face recognition includes: face matching and / or anti-counterfeiting recognition.

[0100] When a user activates the facial recognition function, they must first input the correct facial 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 non-zero polarization degree toward the correct face 100. The polarized light reflected by the correct face carries polarization information corresponding to the target object's contour surface. The two beams of polarized light are incident on the image sensor 400 in chronological order, generating two base polarization images based on the order in which they were incident, thus forming the base image.

[0101] When the database image is entered and the user needs to perform facial recognition during normal use, the image acquisition device 10 is started, and the first light source 200 and the second light source 300 each emit polarized light with a polarization degree not equal to 0 toward the face to be verified, and after being reflected by the face to be verified, the light is incident on the image sensor 400 in chronological order. In this way, the image sensor 400 can generate two polarization images in sequence according to the incident order of the two (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 database image, the facial recognition result can be obtained.

[0102] When face recognition includes face matching verification, the face recognition result includes whether the face matches (passes or fails). Similarly, when face recognition includes anti-counterfeiting verification, the face recognition result also includes whether the face is a real person or a forgery such as a photo, video, or silicone face mold. It is understood that there is no restriction on the order of S10 and S20.

[0103] Optionally, S30 can be specifically as follows: performing two-dimensional face matching verification based on the first polarization image formed first to obtain a two-dimensional face matching result; if the two-dimensional face matching result is failed, the face recognition result is obtained as a mismatch; if the two-dimensional face matching result is passed, the face recognition result is obtained as a match, and then further anti-counterfeiting identification is performed based on the first polarization image formed first and the second polarization image formed later.

[0104] Specifically, a two-dimensional face matching verification is performed based on the first polarization image formed to obtain a two-dimensional face matching result. This allows the face recognition result to be directly concluded as a mismatch when the two-dimensional face matching result fails, thus terminating subsequent anti-counterfeiting recognition, which helps save data processing.

[0105] Furthermore, if the 2D face matching result is a pass, the face recognition result is considered a match. The depth image to be verified is formed based on the code value difference at the same pixel position between the first polarization image formed first and the second polarization image formed later. The depth image to be verified is then compared with the base database depth image to perform anti-counterfeiting identification. The base database depth image is formed by the code value difference at the same pixel position between the two base database polarization images formed for the correct face in the aforementioned input stage.

[0106] Optionally, the aforementioned face recognition method can be implemented based on a specific electronic device, such as an electronic device that includes at least a device body and an image acquisition device, the image acquisition device includes at least the aforementioned first light source, second light source, polarization device and image sensor with a photosensitive unit array 410, wherein 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 by referring to the aforementioned relevant 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.

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

[0108] S31: Perform two-dimensional face matching verification according to the first polarization image, and obtain a two-dimensional face matching result.

[0109] 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 identification is performed according to the first polarization image and the second polarization image, and an anti-counterfeiting identification result is obtained.

[0110] 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 after S10 and then S31. If the 2D face matching result is passed, S20 and S32 are executed again; if the 2D face matching result is failed, S20 is not executed again.

[0111] A first polarization image is acquired using a first light source, a polarizer, and a photosensitive unit array. Because the polarization directions of the first light source and the polarizer are perpendicular, the first polarization image contains the least information. A second polarization image is acquired using a second light source, a polarizer, and a photosensitive unit array. Because the polarization directions of the second light source and the polarizer are the same, the second polarization image contains the most information. The information difference between the two polarization images is maximized, facilitating target recognition.

[0112] This allows for image recognition, or two-dimensional face matching verification, using the first polarized image and the underlying database image, and yields a two-dimensional face matching result. The polarization direction of the first light source is perpendicular to that of the polarization device, meaning the polarization direction of the light emitting end is perpendicular to that of the light receiving end. This minimizes the presence of light spots caused by attacking materials (i.e., counterfeit objects) or facial reflections, ensuring clarity of the first polarized image and facilitating face matching verification.

[0113] As previously described, the 2D face matching results include a pass and a fail. Subsequent anti-counterfeiting identification can take different actions based on the 2D face matching result. For example, if the 2D face matching result is a fail, face recognition will fail immediately and no further anti-counterfeiting identification will be performed. If the 2D face matching result is a pass, anti-counterfeiting identification will be performed based on the first polarization image and the second polarization image to obtain an anti-counterfeiting identification result.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] Of course, the above-mentioned face recognition method can be applied to the aforementioned electronic devices.

[0118] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An image acquisition device, characterized in that: The system comprises a light source group and an image sensor arranged in sequence along an optical path, wherein the light source group comprises two light sources for respectively emitting polarized light, the polarization degrees 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, and the polarized light emitted by the two light sources, after being reflected by a target object, each carries polarization information corresponding to the contour surface of the target object and sequentially enters the image sensor.

2. The image acquisition device according to claim 1, wherein: At least one of the light sources meets the following conditions: The light source includes a light emitting element, and the light emitting element is used to emit the polarized light emitted by the light source; Alternatively, 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 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 provided on the light emitting side of the laser, and the diffusion element is used to expand the light emitting angle of the laser.

4. The image acquisition device according to claim 3, wherein: 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.

5. The image acquisition device according to claim 3, wherein: 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, and the packaged light source also includes a package carrier and a support structure. The laser is fixed to the package carrier, and the support structure is fixed to the package carrier and is located next to the laser. The polarizing element and the diffusion element are separate parts, 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.

6. The image acquisition device according to claim 3, wherein: 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, and the packaged light source also includes a substrate, a package carrier and a supporting structure. The laser is fixed to the package carrier, and the supporting structure is fixed to the package carrier and is located next to the laser. The polarizing element is a polarizing unit on the surface of one side of the substrate, and the diffusion element is a diffusion unit on the surface of the other side of the substrate. The substrate is fixed to the supporting 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.

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

9. The image acquisition device according to any one of claims 1 to 6, wherein: The two light sources have the same light emitting wavelength band.

10. The image acquisition device according to any one of claims 1 to 3, characterized in that: The image acquisition device further includes a narrow bandpass filter, which is located on the light receiving side of the image sensor. The bandpass wavelength of the narrow bandpass filter covers the light emission wavelengths of the two light sources.

11. The image acquisition device according to claim 10, wherein: The light emission band of at least one of the light sources is 940 nm, and the bandpass band of the narrow bandpass filter is 940 nm ± 10 nm.

12. The image acquisition device according to any one of claims 1 to 6, wherein: 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, the image sensor includes a photosensitive unit array, and 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 lights 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, wherein: The polarization directions of the polarized lights emitted by the two light sources are respectively vertical and horizontal, and the polarization direction of the polarization device is vertical or horizontal.

16. An electronic device, characterized in that: The device comprises a device body and the image acquisition device according to any one of claims 1 to 15, wherein the image acquisition device is arranged on the device body.

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