Vein palmprint recognition equipment

Abstract

The utility model relates to the technical field of vein palmprint identification, in particular to vein palmprint identification equipment, which comprises a main control chip, an infrared light source module, an optical imaging module, a living body detection module, a heat dissipation structure and an anti-counterfeiting processing module. According to the utility model, the structure is novel, infrared light can uniformly irradiate a palm, edge dark areas or center overexposure can be avoided, vein image quality can be improved, ambient light interference can be effectively inhibited, aberration can be reduced, blood vessel edge definition can be improved, and counterfeiting means such as silica gel artificial hands, photos or vein printing can be effectively resisted; the LED working temperature stability is ensured, wavelength drift is avoided, the service life is prolonged, the palm of a user is automatically adjusted to the optimal imaging position, the operation difficulty is reduced, the recognition success rate is improved, stable imaging can be ensured under different illumination conditions, the calculation amount is reduced while the precision is ensured, the recognition efficiency is high, and the energy consumption is low.

Description

Technical Field

[0001] This utility model relates to the field of vein palmprint recognition technology, specifically a vein palmprint recognition device. Background Technology

[0002] Vein and palmprint recognition technology, as a highly secure biometric identification method, has been widely used in financial payments, access control systems, and medical authentication in recent years. Compared to traditional biometric technologies such as fingerprints and faces, vein recognition has advantages such as strong liveness detection capabilities, difficulty in forgery, and non-contact data collection. However, existing vein recognition devices still have the following technical problems:

[0003] (1) Insufficient uniformity of infrared light source: Existing devices mostly use ordinary array-type infrared LEDs, which have uneven light source distribution, resulting in dark edges or overexposure in vein images, affecting recognition accuracy. Some solutions attempt to improve uniformity by increasing the number of LEDs, but this leads to increased power consumption and heat dissipation problems;

[0004] (2) Limited optical imaging quality: Traditional lens groups suffer from chromatic aberration and spherical aberration, especially in near-infrared imaging, which leads to blurred blood vessel edges. In addition, ambient light interference (such as sunlight or indoor lighting) reduces the signal-to-noise ratio, and the wavelength matching accuracy of existing narrowband filters is insufficient to effectively suppress stray light;

[0005] (3) Low reliability of liveness detection: Most schemes rely on only a single static feature (such as vein texture), which is easily deceived by high-precision imitation materials. A few schemes use dynamic detection (such as blood flow analysis), but the sensor and imaging optical path are separated, resulting in complex structure and response delay;

[0006] (4) Low heat dissipation efficiency: High-power infrared LEDs generate a lot of heat when working for a long time. Traditional heat dissipation designs (such as metal heat sinks) have limited effectiveness in miniaturized devices, leading to LED wavelength drift and affecting imaging stability.

[0007] (5) Limited anti-counterfeiting methods: Existing anti-counterfeiting technologies are mostly based on two-dimensional image analysis, which cannot effectively identify three-dimensional vascular structures or dynamic blood flow characteristics, and are difficult to deal with emerging advanced counterfeiting methods such as bionic venous membranes.

[0008] (6) User experience needs to be optimized: Users need to repeatedly adjust the position of their palms when operating, and there is a lack of intelligent guidance mechanism, which leads to an increased recognition failure rate, especially for elderly or disabled users.

[0009] No solutions have yet been proposed for the relevant technical issues. Utility Model Content

[0010] To address the problems in related technologies, this utility model proposes a vein palmprint recognition device to overcome the aforementioned technical issues in existing technologies. The purpose of this utility model is to ensure uniform infrared light illumination of the palm, avoiding dark areas at the edges or overexposure in the center, improving vein image quality, effectively suppressing ambient light interference, reducing aberrations, improving the clarity of blood vessel edges, and effectively resisting forgery methods such as silicone prosthetic hands, photographs, or printed veins. The thermally conductive silicone layer and micro-vortex fan work together to dissipate heat, ensuring stable LED operating temperature, avoiding wavelength drift, extending lifespan, automatically adjusting the user's palm to the optimal imaging position, reducing operational difficulty, improving recognition success rate, ensuring stable imaging under different lighting conditions, maintaining accuracy while reducing computational load, and achieving fast recognition efficiency and low energy consumption.

[0011] To achieve the above objectives, this utility model provides the following technical solution: a vein palmprint recognition device, comprising:

[0012] Main control chip;

[0013] The infrared light source module uses an array of semiconductor light-emitting diodes with a specific wavelength of 850-940nm, and the light-emitting surface of the infrared light source module is provided with a light-diffusing sheet.

[0014] An optical imaging module includes a CMOS sensor with a narrow bandpass filter and an aspherical lens group, wherein the center wavelength of the narrow bandpass filter is matched with the infrared light source wavelength of the infrared light source module.

[0015] The liveness detection module, integrated into the optical path of the optical imaging module, includes a dynamic blood flow detection sensor;

[0016] The heat dissipation structure consists of a thermally conductive silicone layer and a micro vortex fan, with the thermally conductive silicone layer tightly attached to the rear end of the infrared light source module;

[0017] The anti-counterfeiting processing module is connected to the main control chip and is used to analyze the three-dimensional features of blood vessels and blood flow dynamics.

[0018] Preferably, the semiconductor light-emitting diodes of the infrared light source module are arranged in concentric circles, and the luminous power of the infrared light source module can be dynamically adjusted according to the detection data of the ambient light sensor.

[0019] Preferably, the aspherical lens group of the optical imaging module includes one aspherical lens and one achromatic lens, with a combined focal length of 8-12mm and an F-number ≤2.0.

[0020] Preferably, the liveness detection module includes:

[0021] Photoelectric pulse sensor is used to collect subcutaneous capillary pulsation signals;

[0022] Temperature sensor to detect the temperature gradient distribution on the surface of the palm;

[0023] The signal is used for liveness detection via a multimodal fusion algorithm.

[0024] Preferably, the speed of the micro vortex fan in the heat dissipation structure is controlled in conjunction with the working power of the infrared light source, and the airflow channel of the micro vortex fan is spiral-shaped.

[0025] Preferably, it also includes a contact guide mechanism, comprising:

[0026] A height-adjustable palm rest with a pressure-sensing array on its surface;

[0027] A 3D positioning laser pointer is used to guide the palm to the optimal imaging position.

[0028] Preferably, the main control chip incorporates a blood vessel texture enhancement algorithm, employing an image processing method that combines Gabor filter banks with local binary mode.

[0029] Preferably, the anti-counterfeiting processing module detects the movement trajectory of hemoglobin in blood vessels using the time-domain difference method and establishes a three-dimensional vascular topology model.

[0030] Compared with the prior art, the beneficial effects of this utility model are:

[0031] (1) This utility model is a vein palm print recognition device. By using an array of near-infrared semiconductor light-emitting diodes arranged in concentric circles, combined with a light-diffusing sheet, infrared light is uniformly irradiated onto the palm, avoiding dark areas at the edges or overexposure in the center, thus improving the quality of the vein image. The narrow bandpass filter is strictly matched with the wavelength of the infrared light source, effectively suppressing ambient light interference. The combination of an aspherical lens and an achromatic lens (F value ≤ 2.0) reduces aberrations and improves the clarity of the blood vessel edges.

[0032] (2) This utility model is a vein palm print recognition device. By integrating photoelectric pulse sensor and temperature sensor, and combining algorithm to judge the liveness characteristics, it can effectively resist counterfeiting methods such as silicone fake hand, photo or vein printing. By using time domain difference method to track the movement trajectory of hemoglobin in real time, a three-dimensional vascular topology model is established to further enhance the anti-counterfeiting capability.

[0033] (3) This utility model is a vein palm print recognition device. It uses a thermally conductive silicone layer and a micro vortex fan to work together to dissipate heat. Combined with power-speed linkage control, it ensures stable LED operating temperature, avoids wavelength drift, optimizes heat dissipation efficiency, and improves heat dissipation performance by more than 30% compared with traditional straight air ducts, thus extending the service life of the device.

[0034] (4) This utility model is a vein palm print recognition device. Through the liftable palm support and three-dimensional positioning laser indicator, the user's palm is automatically adjusted to the best imaging position, reducing the difficulty of operation and improving the recognition success rate. The infrared light source power is dynamically adjusted with the ambient light intensity to ensure stable imaging under different lighting conditions.

[0035] (5) This utility model is a vein palm print recognition device. The main control chip adopts the Gabor filter + LBP blood vessel enhancement algorithm to reduce the amount of calculation while ensuring accuracy. The recognition time is ≤0.5 seconds. When the device does not detect the palm, it automatically reduces the LED power to save energy. Attached Figure Description

[0036] Figure 1 This is a structural block diagram of the entire utility model. Attached image description:

[0038] 101. Infrared light source module; 102. Optical imaging module; 103. Liveness detection module; 1031. Photoelectric pulse sensor; 1032. Temperature sensor; 104. Heat dissipation structure; 105. Anti-counterfeiting processing module; 106. Ambient light sensor; 107. Contact guidance mechanism; 1071. Adjustable palm rest; 1072. Three-dimensional positioning laser indicator. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0040] Example

[0041] Please see Figure 1 As shown, this utility model proposes a technical solution for a vein palmprint recognition device: a vein palmprint recognition device, comprising:

[0042] Main control chip; specifically, the main control chip is the overall intelligent hub;

[0043] The infrared light source module 101 uses an array of semiconductor light-emitting diodes with a specific wavelength of 850-940nm. The light-emitting surface of the infrared light source module 101 is provided with a light-diffusing sheet. Specifically, it solves the problem of low accuracy caused by existing rectangular arrangement or non-diffusing design. The 850-940nm semiconductor light-emitting diodes are invisible light LEDs, which are optimized for vein imaging (hemoglobin has a high absorption rate in this band), avoid interference from skin surface reflection, and adjust the power according to the ambient light.

[0044] The optical imaging module 102 includes a CMOS sensor with a narrow bandpass filter and an aspherical lens group, wherein the center wavelength of the narrow bandpass filter is matched with the infrared light source wavelength of the infrared light source module 101.

[0045] The liveness detection module 103 is integrated into the optical path of the optical imaging module 102 and includes a dynamic blood flow detection sensor.

[0046] The heat dissipation structure 104 consists of a thermally conductive silicone layer and a micro vortex fan. The thermally conductive silicone layer is tightly attached to the rear end of the infrared light source module 101. Specifically, the thermally conductive silicone layer is in direct physical contact with the heat dissipation structure 104. The fan speed range is 2000-8000 RPM (corresponding to a PWM duty cycle of 20%-80%).

[0047] The anti-counterfeiting processing module 105 is connected to the main control chip and is used to analyze the three-dimensional features of blood vessels and dynamic information of blood flow.

[0048] In this embodiment, the main control chip generates a PWM wave (frequency 1kHz, duty cycle adjustable from 0-100%) through the TIM timer. The main control chip controls the power of the LED array through the PWM dimming circuit. The I2C digital signal of the ambient light sensor 106 is fed back to the main control chip to dynamically adjust the PWM duty cycle.

[0049] The CMOS sensor of the optical imaging module 102 transmits image data to the main control chip through the MIPI CSI-2 interface. The narrow bandpass filter is mechanically fixed at the front end of the lens group. The main control sends a VSYNC signal to synchronize the light source flashing and image acquisition.

[0050] The infrared light source module (101) and the optical imaging module (102) are at an angle of 30°-45° (to avoid specular reflection);

[0051] The concentricity error of the optical axis of each lens is ensured to be less than 0.1 mm by using locating pins.

[0052] Furthermore, the semiconductor light-emitting diodes of the infrared light source module 101 are arranged in concentric circles, and the luminous power of the infrared light source module 101 can be dynamically adjusted according to the detection data of the ambient light sensor 106.

[0053] In this embodiment, concentric circles are used to achieve uniform irradiation and solve the problem of edge attenuation.

[0054] Furthermore, the aspherical lens group of the optical imaging module 102 includes an aspherical lens and an achromatic lens, with a combined focal length of 8-12mm and an F-number ≤2.0.

[0055] Please see Figure 1 As shown, the liveness detection module 103 further includes:

[0056] The photoelectric pulse sensor 1031 is used to collect subcutaneous capillary pulsation signals.

[0057] Temperature sensor 1032 detects the temperature gradient distribution on the surface of the palm.

[0058] The signal is used to determine the liveness of the subject through a multimodal fusion algorithm.

[0059] In this embodiment, the photoelectric pulse sensor 1031 acquires analog signals through an ADC, and the digital output of the temperature sensor 1032 (such as DS18B20) is directly connected to the main control GPIO, and the main control runs a multimodal fusion algorithm.

[0060] Furthermore, the speed of the miniature vortex fan in the heat dissipation structure 104 is linked to the working power of the infrared light source, and the airflow channel of the miniature vortex fan is spiral-shaped.

[0061] In this embodiment, the control loop is: infrared LED temperature → thermistor → main control ADC → calculate fan speed → drive MOSFET to control eddy current fan, and the PID algorithm is used to realize closed-loop control.

[0062] Please see Figure 1 As shown, it further includes a contact guidance mechanism 107, comprising:

[0063] The adjustable palm rest 1071 has a pressure-sensing array on its surface;

[0064] The 3D positioning laser pointer 1072 is used to guide the palm to the optimal imaging position.

[0065] In this embodiment, the pressure sensing array transmits matrix data via an SPI interface;

[0066] 1072 3D positioning laser pointer: Main control PWM drives 650nm laser diode;

[0067] Lifting motor: H-bridge drive circuit + encoder feedback.

[0068] The lifting guide rail of the height-adjustable palm rest 1071 is connected to the pressure sensor by a floating connection to avoid mechanical stress affecting the sensing accuracy.

[0069] Furthermore, the main control chip incorporates a blood vessel texture enhancement algorithm, employing an image processing method that combines Gabor filter banks with local binary mode.

[0070] In this embodiment, the DSP core (such as Cortex-M7) of the main control chip runs:

[0071] / / Pseudocode for the finite-difference time-domain method

[0072] for(frame=0;frame<5;frame++){

[0073] hemoglobin_movement+=abs(frame[t]-frame[t-1]);

[0074] }

[0075] 3D modeling uses OpenVX hardware acceleration.

[0076] Furthermore, the anti-counterfeiting processing module 105 detects the movement trajectory of hemoglobin in blood vessels using the time-domain difference method and establishes a three-dimensional vascular topology model.

[0077] In this embodiment, the data processing flow of the anti-counterfeiting processing module 105 is: original image → main control preprocessing → blood vessel enhancement algorithm (Gabor+LBP) → temporal difference analysis → 3D modeling, which requires the use of the main control hardware accelerator (such as the FPU unit of Cortex-M7).

[0078] This invention employs a concentric array of near-infrared semiconductor light-emitting diodes, combined with a light-diffusing sheet, to ensure uniform infrared light illumination of the palm, avoiding dark areas at the edges or overexposure in the center, thus improving the quality of vein images. A narrow-bandpass filter is strictly matched with the wavelength of the infrared light source to effectively suppress ambient light interference. The combination of an aspherical lens and an achromatic lens (F-value ≤ 2.0) reduces aberrations and improves the clarity of blood vessel edges.

[0079] It integrates a photoelectric pulse sensor (to detect subcutaneous blood flow pulsation) and a temperature sensor (to analyze the temperature gradient of the palm), and combines algorithms to determine the characteristics of a living body, effectively resisting counterfeiting methods such as silicone prosthetic hands, photos, or vein printing. It also uses the time-domain difference method to track the movement trajectory of hemoglobin in real time and establish a three-dimensional vascular topology model to further enhance anti-counterfeiting capabilities.

[0080] The thermally conductive silicone layer and the micro vortex fan work together to dissipate heat, combined with power-speed linkage control, to ensure stable LED operating temperature, avoid wavelength drift, and optimize heat dissipation efficiency. Compared with traditional straight air ducts, the heat dissipation performance is improved by more than 30%, extending the service life of the equipment.

[0081] The user's hand is automatically adjusted to the optimal imaging position by the height-adjustable palm support 1071 and the three-dimensional positioning laser pointer 1072, which reduces the difficulty of operation and improves the recognition success rate. The infrared light source power is dynamically adjusted according to the ambient light intensity to ensure stable imaging under different lighting conditions.

[0082] The main control chip uses a Gabor filter + LBP blood vessel enhancement algorithm, which reduces the amount of computation while ensuring accuracy. The recognition time is ≤0.5 seconds. When the device does not detect the palm, it automatically reduces the LED power to save energy.

[0083] In the description of this utility model, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "side", "top", "inner", "front", "center", "both ends", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0084] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0085] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A vein palmprint identification device, characterized by, It comprises: a master chip; an infrared light source module (101) using arrayed semiconductor light-emitting diodes of specific wavelength 850-940 nm, the light-emitting surface of the infrared light source module (101) being provided with a light-uniform diffusion sheet; an optical imaging module (102) containing a CMOS sensor with a narrow-band filter and an aspheric lens group, the center wavelength of the narrow-band filter matching the wavelength of the infrared light source of the infrared light source module (101); a living body detection module (103) integrated in the optical path of the optical imaging module (102) and containing a dynamic blood flow detection sensor; a heat dissipation structure (104) composed of a heat-conducting silica gel layer and a micro eddy current fan, the heat-conducting silica gel layer being closely attached to the rear end of the infrared light source module (101); a forgery prevention processing module (105) connected with the master chip and used for analyzing the three-dimensional features of blood vessels and dynamic information of blood flow.

2. The vein palmprint recognition device according to claim 1, characterized in that: The semiconductor light-emitting diodes of the infrared light source module (101) are arranged in concentric circles, and the light-emitting power of the infrared light source module (101) can be dynamically adjusted according to the detection data of the ambient light sensor (106).

3. The vein palmprint recognition device of claim 1, wherein: The aspheric lens group of the optical imaging module (102) contains one aspheric lens and one achromatic lens, and the combined focal length is 8-12 mm, and the F value is ≤2.

0.

4. The vein palmprint recognition device of claim 1, wherein: The living body detection module (103) comprises: a photoelectric pulse sensor (1031) for collecting subcutaneous capillary pulsatile signals; a temperature sensor (1032) for detecting the temperature gradient distribution of the palm surface; The signals are processed by a multi-modal fusion algorithm to determine the living body.

5. The apparatus according to claim 1, wherein: The rotation speed of the micro eddy current fan of the heat dissipation structure (104) is linked with the working power of the infrared light source, and the airflow channel of the micro eddy current fan is in a spiral shape.

6. The vein palmprint recognition device of claim 1, wherein: It also includes a contact guiding mechanism (107) comprising: a liftable palm bracket (1071) provided with a pressure sensing array on its surface; a three-dimensional positioning laser pointer (1072) for guiding the palm to the optimal imaging position.

7. The vein palmprint recognition device of claim 1, wherein: The master chip is built-in with a blood vessel texture enhancement algorithm, and adopts a combination of Gabor filter set and local binary pattern image processing method.

8. The vein palmprint recognition device of claim 1, wherein: The forgery prevention processing module (105) detects the motion trajectory of hemoglobin in blood vessels by time domain difference method and establishes a three-dimensional blood vessel topology model.

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