Palm print and palm vein single-camera acquisition module and recognition method

Abstract

The present application provides a palm print and palm vein single-camera acquisition module and an identification method. The palm print and palm vein single-camera acquisition module includes: a circuit board, an infrared fill light unit, a first polarizer, a lens, a camera, a converter, a second polarizer, and a third polarizer; the infrared fill light unit, the camera, and the converter are arranged on the circuit board, the first polarizer is arranged on the infrared fill light unit, the lens is arranged on the camera, the second polarizer and the third polarizer are arranged on the converter, and the converter is used to convert the second polarizer and the third polarizer between the lens and the camera, the first polarizer and the second polarizer have the same polarization direction, and the polarization directions of the first polarizer and the third polarizer are at a preset angle. The palm print and palm vein single-camera acquisition module of the present application has consistent distortion and global brightness of the palm print and palm vein after imaging.

Description

Technical Field

[0001] The present application belongs to the field of biometric identification technology, and more specifically, to a palm print and palm vein single-camera acquisition module and an identification method. Background Art

[0002] Palm vein recognition technology uses the difference in the absorption rate of near-infrared light between deoxyhemoglobin in the vein and other physiological tissues, and adopts near-infrared reflection imaging to obtain the palm vein image information, digitize the vein characteristics, and use this as the basis for identity information recognition and authentication. Palm print recognition refers to the various lines on the palm surface between the wrist and fingers, which can be directly obtained from the epidermis.

[0003] In order to obtain palm prints and palm veins separately, there are two methods in the prior art: the first is to obtain palm prints and palm veins separately based on a dual-camera structure, and the other is a single camera with two sets of infrared fill light structures. However, no matter which method is used to obtain palm prints and palm veins, the relative position of the light source and the imaging point changes relatively, resulting in the distortion of the palm prints and palm veins after imaging and the inconsistency of the global brightness, which reduces the matching degree of palm prints and palm veins during feature fusion.

[0004] In addition, with the upgrading of technology, high-imitation prosthesis attacks and video image technology attacks are becoming more and more realistic, and the existing palm print and palm vein recognition technology still has the problem of insufficient anti-attack ability. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a palm print and palm vein single-camera acquisition module and recognition method to solve the technical problems of the prior art in the palm vein recognition process, such as the distortion of the imaged palm prints and palm veins, the inconsistency of the global brightness, and the insufficient anti-attack capability.

[0006] To achieve the above-mentioned purpose, the technical solution adopted in the present application is: to provide a palm print and palm vein single-camera acquisition module, the palm print and palm vein single-camera acquisition module comprising: a circuit board, an infrared fill light unit, a first polarizer, a lens, a camera, a converter, a second polarizer and a third polarizer, the infrared fill light unit, the camera and the converter are arranged on the circuit board, the first polarizer is arranged on the infrared fill light unit, the lens is arranged on the camera, the second polarizer and the third polarizer are arranged on the converter, the converter is used to convert the second polarizer and the third polarizer between the lens and the camera, the first polarizer and the second polarizer have the same polarization direction, and the polarization directions of the first polarizer and the third polarizer are at a preset angle.

[0007] In another preferred embodiment of the present application, the plurality of infrared fill light units are distributed in a ring array with the camera as the center, and the first polarizer is in a circular ring structure covering the light-emitting surfaces of the plurality of infrared fill light units.

[0008] In another preferred embodiment of the present application, the palm print and palm vein single-camera acquisition module also includes a ranging unit, and the ranging unit is arranged on the circuit board. After the ranging unit detects the palm, it can wake up the infrared fill light unit and the camera.

[0009] In another preferred embodiment of the present application, the palm print and palm vein single-camera acquisition module also includes a light intensity adjustment unit, and a plurality of the ranging units are distributed in a circular array with the camera as the center. After each ranging unit independently detects the palm, the light intensity adjustment unit adjusts the light intensity of one or more infrared fill light units closest to the ranging unit according to the distance value.

[0010] In another preferred embodiment of the present application, the palm print and palm vein single-camera acquisition module further includes an infrared filter, and the infrared filter is disposed between the lens and the camera.

[0011] In another preferred embodiment of the present application, the converter includes a base and a control circuit, an active hole is set in the middle of the base, a conductive frame is set in the active hole, the control circuit is connected to the conductive frame, the second polarizer and the third polarizer are set in the conductive frame, and the first permanent magnet and the second permanent magnet are correspondingly set on both sides of the active hole, the magnetic poles of the first permanent magnet and the second permanent magnet are in opposite directions, and the Ampere force of the conductive frame is controlled by changing the direction of the current passing through the conductive frame.

[0012] In another preferred embodiment of the present application, a fourth polarizer is further provided in the conductive frame, and the fourth polarizer is located between the second polarizer and the third polarizer. Assuming that the polarization angle of the first polarizer and the second polarizer is α, the polarization angle of the third polarizer is β, and the polarization angle of the third polarizer is γ, then α<γ<β.

[0013] In another preferred embodiment of the present application, the polarization directions of the first polarizer and the third polarizer form an angle of 90 degrees.

[0014] In another preferred embodiment of the present application, a plurality of magnetic shielding sheets are spaced apart on both sides of the inner wall of the movable hole, and the control circuit is a pulse control circuit, and the pulse control circuit is used to switch high and low levels.

[0015] The present application also provides a palm print and palm vein recognition method, which is applied to any one of the above-mentioned embodiments 1 to 3, and the palm print and palm vein recognition method comprises the steps of:

[0016] During the conversion process of the converter, a plurality of frames of palm images are continuously acquired through a camera;

[0017] Convert multiple palm image frames into the input format required by the video recognition network;

[0018] Input the format-converted multi-frame palm images and their time axis into the trained palm print and palm vein anti-counterfeiting video recognition network model;

[0019] The palm print and palm vein anti-counterfeiting video recognition network model outputs anti-counterfeiting recognition results.

[0020] The palm print and palm vein single-camera acquisition module provided by the present application has the following beneficial effects compared with the prior art: based on the same lens focus, the distortion of the palm print and the palm vein is kept consistent during imaging, which can improve the matching degree of the palm print and the palm vein during feature fusion; at the same time, when the palm print and the palm vein are imaged separately, the relative position of the light source and the lens does not change, ensuring that the global brightness of the palm print image and the palm vein image is kept consistent, which can improve the contrast of the palm print feature and the palm vein feature after feature fusion, and enhance the palm print and vein information after fusion.

[0021] Compared with the prior art, the palm print and palm vein recognition method provided by the present application has the following beneficial effects: based on the above-mentioned palm print and palm vein single-camera acquisition module, multiple frames of palm images and their time axes are input into the trained palm print and palm vein anti-counterfeiting video recognition network module, and the change process of the palm print and palm vein feature areas is tracked to distinguish between living objects and prostheses, thereby improving the anti-counterfeiting recognition capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 A schematic diagram of the principle of a palm print and palm vein single-camera acquisition module provided in the first embodiment of the present application;

[0024] Figure 2 Based on Figure 1 The palm print effect diagram obtained by the palm print and palm vein single camera acquisition module;

[0025] Figure 3 Based on Figure 1 The palm vein effect diagram obtained by the palm print and palm vein single-camera acquisition module;

[0026] Figure 4A three-dimensional structural diagram of a palm print and palm vein single-camera acquisition module provided in the second embodiment of the present application;

[0027] Figure 5 A three-dimensional structural diagram of a converter provided in the third embodiment of the present application;

[0028] Figure 6 A schematic diagram of the steps of the palm print and palm vein recognition method provided in the fourth embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0030] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0031] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0033] In the first embodiment of this application, please refer to Figure 1The palm print and palm vein single-camera acquisition module includes: a circuit board 10, an infrared fill light unit 20, a first polarizer 30, a lens 40, a camera 50, a converter 60, a second polarizer 70, and a third polarizer 80. The infrared fill light unit 20, the camera 50, and the converter 60 are arranged on the circuit board 10. The first polarizer 30 is arranged on the infrared fill light unit 20. The lens 40 is arranged on the camera 50. The second polarizer 70 and the third polarizer 80 are arranged on the converter 60. The converter 60 is used to convert the second polarizer 70 and the third polarizer 80 between the lens 40 and the camera 50. The polarization directions of the first polarizer 30 and the second polarizer 70 are the same, and the polarization directions of the first polarizer 30 and the third polarizer 80 are at a preset angle.

[0034] It can be understood that, assuming that the polarization angles of the first polarizer 30 and the second polarizer 70 are α, and the polarization angle of the third polarizer 80 is β, for example, the infrared fill light unit 20 is a near-infrared LED lamp, and the infrared light emitted by the infrared fill light unit 20 is omnidirectional light, then after the omnidirectional light passes through the first polarizer 30, only the infrared light with a polarization angle of α is retained, and then the infrared light with a polarization angle of α is irradiated on the palm, forming two types of light propagation paths, the first type is directly reflected by the palm surface, and the second type enters the palm, is refracted, and then is emitted from the palm.

[0035] For example, the converter 60 may be an electric lever, and the second polarizer 70 and the third polarizer 80 are disposed at the ends of the electric lever, and the electric lever drives the second polarizer 70 and the third polarizer 80 to switch between the lens 40 and the camera 50 .

[0036] Please also read Figure 2 When the converter 60 converts the second polarizer 70 to between the lens 40 and the camera 50, the polarization directions of the first polarizer 30 and the second polarizer 70 are the same, so the reflected infrared light can directly pass through the lens 40, the second polarizer 70 and the camera 50 in sequence, while the polarization angle of the refracted light changes completely and cannot pass through the second polarizer 70. At this time, the camera 50 can obtain clear palm print features but no palm vein features.

[0037] Please also read Figure 3When the converter 60 converts the third polarizer 80 to between the lens 40 and the camera 50, the polarization directions of the first polarizer 30 and the third polarizer 80 form a preset angle, so most of the reflected infrared light is filtered by the third polarizer 80, and part of the refracted light is absorbed by the hemoglobin in the vein, and the other part changes the polarization angle due to refraction, and can then pass through the lens 40, the third polarizer 80 and the camera 50 in sequence. At this time, the camera 50 can obtain clear palm vein features without palm print features.

[0038] In this way, combined with the existing conventional palm feature recognition algorithm, the palm print image and palm vein image will be enhanced separately to improve the clarity and contrast of the image, reduce noise and blur, and make the features in the image more obvious; then the palm print features and palm vein features are extracted separately for feature fusion processing, so as to obtain the fusion features of palm print and palm vein.

[0039] The palm print and palm vein single-camera acquisition module and recognition method provided by the present application have the following beneficial effects compared with the prior art: based on the focus of the same lens 40, the distortion of the palm print and the palm vein is kept consistent during imaging, which can improve the matching degree of the palm print and the palm vein during feature fusion; at the same time, when the palm print and the palm vein are imaged separately, the relative position of the light source and the lens 40 does not change, ensuring that the global brightness of the palm print image and the palm vein image remains consistent, which can improve the contrast of the palm print feature and the palm vein feature after feature fusion, and enhance the palm print and vein information after fusion.

[0040] In the second embodiment of this application, please refer to Figure 4 The difference between the second embodiment and the first embodiment is that: the plurality of infrared fill light units 20 are distributed in a ring array with the camera 50 as the center, and the first polarizer 30 is in a circular ring structure covering the light-emitting surfaces of the plurality of infrared fill light units 20.

[0041] It can be understood that the plurality of infrared fill light units 20 are distributed in a ring array, which can improve the uniformity of the fill light, and the first polarizer 30 is in a circular ring structure, which can improve the coverage and reduce light leakage.

[0042] For further information, please also refer to Figure 4 The palm print and palm vein single-camera acquisition module also includes a distance measuring unit 91, which is disposed on the circuit board 10. The distance measuring unit 91 can wake up the infrared fill light unit 20 and the camera 50 after detecting a palm.

[0043] It can be understood that the distance measuring unit 91 can be a laser distance measuring device. After using the distance measuring unit 91, the infrared fill light unit 20 and the camera 50 can remain asleep when idle. After the distance measuring unit 91 detects a palm, it wakes up the infrared fill light unit 20 and the camera 50 to achieve the purpose of energy saving.

[0044] For further information, please also refer to Figure 4 The palm print and palm vein single-camera acquisition module also includes a light intensity adjustment unit (not shown), and a plurality of the distance measuring units 91 are distributed in a circular array with the camera 50 as the center. After each distance measuring unit 91 independently detects the palm, the light intensity adjustment unit adjusts the light intensity of one or more infrared fill light units 20 closest to the distance measuring unit 91 according to the distance value.

[0045] It is understandable that, affected by the degree of palm tilt, even if the light-emitting surface is uniform, the fill light intensity near the palm will be higher than that far from the palm. In this embodiment, each ranging unit 91 can control the light intensity of one or more infrared fill light units 20 closest to the ranging unit 91 by ranging. For example, the farther the distance, the higher the light intensity of one or more infrared fill light units 20 closest to the ranging unit 91, and vice versa. Finally, uniform fill light is achieved on the tilted or uneven palm surface.

[0046] For further information, please also refer to Figure 1 The palm print and palm vein single-camera acquisition module also includes an infrared filter 93 , and the infrared filter 93 is arranged between the lens 40 and the camera 50 .

[0047] It is understandable that, since there may be interference from visible light in the environment, the infrared filter 93 can filter out the interference from visible light, so that the camera 50 can obtain a pure infrared image.

[0048] In the third embodiment of this application, please refer to Figure 5 The difference between the third embodiment and the first embodiment is that: the converter 60 includes a base 61 and a control circuit (not shown), a movable hole 63 is set in the middle of the base 61, a conductive frame 64 is set in the movable hole 63, the control circuit is connected to the conductive frame 64, the second polarizer 70 and the third polarizer 80 are set in the conductive frame 64, and the first permanent magnet 65 and the second permanent magnet 66 are correspondingly set on both sides of the movable hole 63. The magnetic pole directions of the first permanent magnet 65 and the second permanent magnet 66 are opposite, and the Ampere force of the conductive frame 64 is controlled by changing the direction of the current passing through the conductive frame 64.

[0049] It is understandable that under the magnetic field of different permanent magnets, the conductive frame 64 will be subjected to the Ampere force after conducting. Since the current directions on both sides of the conductive frame 64 are opposite when the control circuit energizes the conductive frame 64, and the magnetic pole directions of the first permanent magnet 65 and the second permanent magnet 66 are opposite, the two sides of the conductive frame 64 will be subjected to the Ampere force in the same direction. Similarly, when the control circuit energizes the conductive frame 64 in the reverse direction, the conductive frame 64 can be reset.

[0050] For further information, please also refer to Figure 5 A fourth polarizer 67 is also provided in the conductive frame 64, and the fourth polarizer 67 is located between the second polarizer 70 and the third polarizer 80. Assuming that the polarization angle of the first polarizer 30 and the second polarizer 70 is α, the polarization angle of the third polarizer 80 is β, and the polarization angle of the third polarizer 80 is γ, then α<γ<β.

[0051] It is understandable that when a fourth polarizer 67 is provided between the second polarizer 70 and the third polarizer 80, due to α<γ<β, when the fourth polarizer 67 is transferred between the lens 40 and the camera 50, both the refracted light and the reflected light can partially enter the camera 50, and then the camera 50 can simultaneously obtain the palm print and palm vein features in the same frame. Preferably, the polarization directions of the first polarizer 30 and the third polarizer 80 are at an angle of 90 degrees. It is worth noting that the infrared light can pass completely when the polarization direction is parallel to the polarization direction of the polarizer, can be completely filtered when the polarization direction of the infrared light is perpendicular to the polarization direction of the polarizer, and can be partially filtered when it is between the above two directions.

[0052] For further information, please also refer to Figure 5 A plurality of magnetic shielding sheets 68 are arranged at intervals on both sides of the inner wall of the movable hole 63. The control circuit is a pulse control circuit, and the pulse control circuit is used to switch high and low levels.

[0053] It is understandable that the magnetic shielding sheet 68 can be made of materials such as Permalloy, which can effectively absorb and reflect the surrounding magnetic field. The pulse control circuit alternately sends high and low levels, for example, first outputs a low level of 0.4 seconds, and the conductive frame 64 moves between a pair of magnetic shielding sheets 68. Due to the interference of the magnetic field, the Ampere force is less than the friction force, causing the conductive frame 64 to pause between the pair of magnetic shielding sheets 68, and then outputs a high level of 0.1 seconds. At this time, the magnetic field is enhanced, the Ampere force is greater than the friction force, and the conductive frame 64 breaks through the magnetic shielding sheet 68 and continues to move, and so on. In this way, the magnetic shielding sheet 68 is combined with the pulse control circuit to suppress the errors caused by inertia and the hardware itself, and improve the control accuracy of the intermittent displacement of the converter 60. At each pause, the camera 50 can obtain a frame of image with both palm print and palm vein features. At each pause, the ratio of the palm print and palm vein feature areas in the image is changing, such as the gradual change process of palm print image-palm print palm vein mixed image-palm vein image, so that the camera 50 can more accurately obtain palm feature images of different forms at intervals.

[0054] In the fourth embodiment of this application, please refer to Figure 6 The present application also provides a palm print and palm vein recognition method, which is applied to the above-mentioned embodiment 3, and the palm print and palm vein recognition method comprises the steps of:

[0055] Step S1, during the conversion process of the converter 60, a plurality of frames of palm images are continuously acquired through the camera 50;

[0056] Step S2, converting the multiple frames of palm images into the input format required by the video recognition network;

[0057] Step S3, inputting the format-converted multiple-frame palm images and their time axis into the trained palm print and palm vein anti-counterfeiting video recognition network model;

[0058] Step S4: the palm print and palm vein anti-counterfeiting video recognition network model outputs the anti-counterfeiting recognition result.

[0059] It can be understood that the time axis is the collection of acquisition times of the multiple-frame palm images. The essence of the multiple-frame palm images and their time axis is to show a change process of the palm print and palm vein feature area during the conversion process of the polarizer. Unlike the detection and recognition model, the video recognition network model can analyze multiple frames of images frame by frame. After combining the time axis, video recognition not only focuses on the content of the current frame, but also tracks the correlation between consecutive frames. In this embodiment, it also tracks a change process of the palm print and palm vein feature area. In this way, the living body and the prosthesis can be distinguished and the anti-counterfeiting recognition capability can be improved.

[0060] It is worth noting that the palm print and palm vein anti-counterfeiting video recognition network model can be trained based on the existing ResNet50 backbone network and Sigmoid activation function. The only difference from the conventional video recognition network model is the training set. The training set in this embodiment is a continuous frame palm print and palm vein image with a time axis or a palm print and palm vein acquisition video.

[0061] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A palm print and palm vein single-camera acquisition module, characterized in that: include: A circuit board, an infrared fill light unit, a first polarizer, a lens, a camera, a converter, a second polarizer, and a third polarizer; The infrared fill light unit, the camera and the converter are arranged on the circuit board, the first polarizer is arranged on the infrared fill light unit, the lens is arranged on the camera, the second polarizer and the third polarizer are arranged on the converter, the converter is used to convert the second polarizer and the third polarizer between the lens and the camera, the polarization directions of the first polarizer and the second polarizer are the same, and the polarization directions of the first polarizer and the third polarizer are at a preset angle; The converter includes a base and a control circuit, a movable hole is arranged in the middle of the base, a conductive frame is arranged in the movable hole, the control circuit is connected to the conductive frame, the second polarizer and the third polarizer are arranged in the conductive frame, a first permanent magnet and a second permanent magnet are arranged on both sides of the movable hole, the magnetic poles of the first permanent magnet and the second permanent magnet are in opposite directions, and the Ampere force of the conductive frame is controlled by changing the direction of the current passing through the conductive frame; A number of magnetic shielding sheets are arranged at intervals on both sides of the inner wall of the movable hole. The control circuit is a pulse control circuit. The pulse control circuit is used to switch high and low levels. The pulse control circuit emits high and low levels alternately. When the pulse control circuit outputs a low level, the conductive frame pauses between a pair of magnetic shielding sheets. When the pulse control circuit outputs a high level, the conductive frame breaks through the magnetic shielding sheets and continues to move. At each pause, the camera acquires a frame of image with both palm print and palm vein features.

2. The palm print and palm vein single-camera acquisition module according to claim 1, characterized in that: The plurality of infrared fill light units are distributed in a ring array with the camera as the center, and the first polarizer is in a circular ring structure covering the light-emitting surfaces of the plurality of infrared fill light units.

3. The palm print and palm vein single-camera acquisition module according to claim 2, characterized in that: The palm print and palm vein single-camera acquisition module also includes a distance measuring unit, which is arranged on the circuit board. After the distance measuring unit detects the palm, it can wake up the infrared fill light unit and the camera.

4. The palm print and palm vein single-camera acquisition module according to claim 3, characterized in that: The palm print and palm vein single-camera acquisition module also includes a light intensity adjustment unit. Several of the ranging units are distributed in a circular array with the camera as the center. After each ranging unit independently detects the palm, the light intensity adjustment unit adjusts the light intensity of one or more infrared fill light units closest to the ranging unit according to the distance value.

5. The palm print and palm vein single-camera acquisition module according to claim 4, characterized in that: The palm print and palm vein single-camera acquisition module also includes an infrared filter, which is arranged between the lens and the camera.

6. The palm print and palm vein single-camera acquisition module according to claim 1, characterized in that: A fourth polarizer is also provided in the conductive frame and is located between the second polarizer and the third polarizer. Assuming that the polarization angles of the first polarizer and the second polarizer are α, the polarization angle of the third polarizer is β, and the polarization angle of the third polarizer is γ, then α<γ<β.

7. The palm print and palm vein single-camera acquisition module according to claim 6, characterized in that: The polarization directions of the first polarizer and the third polarizer form an angle of 90 degrees.

8. A palm print and palm vein recognition method, characterized in that: Applied to the palm print and palm vein single-camera acquisition module of claim 1 or 6, the palm print and palm vein recognition method comprises the steps of: During the conversion process of the converter, a plurality of frames of palm images are continuously acquired through a camera; Convert multiple palm image frames into the input format required by the video recognition network; Input the format-converted multi-frame palm images and their time axis into the trained palm print and palm vein anti-counterfeiting video recognition network model; The palm print and palm vein anti-counterfeiting video recognition network model outputs anti-counterfeiting recognition results.

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