Fingerprint verification method and device based on double-finger fingerprint image acquisition

Abstract

The invention discloses a fingerprint verification method and device based on double-finger fingerprint image acquisition, and relates to the technical field of biological recognition, and the method comprises the following steps: deploying a light sensor, carrying out the primary adjustment of an illumination light source, collecting the light intensity data of the fingerprint surface when two fingers press through the light sensor, and obtaining a fingerprint verification result according to the light intensity data; the method comprises the following steps: deploying a light sensor, constructing a closed-loop adjustment mechanism of primary adjustment, secondary adjustment and quality feedback, acquiring light intensity data of the fingerprint surfaces of the two fingers in real time, judging an abnormal condition, performing secondary adjustment on an illumination light source, acquiring fingerprint images of the two fingers, and judging whether the quality of the fingerprint images reaches the standard or not. According to the two-finger fingerprint verification method, the abnormity of insufficient light source intensity or improper angle is pointedly corrected through secondary adjustment, and the image quality evaluation standard combining the edge sharpness and the effective area proportion provides reliable data support for two-finger fingerprint verification, and the fingerprint verification accuracy and the actual application effect are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biometric identification, in particular to a fingerprint verification method and device based on double-finger fingerprint image acquisition. BACKGROUND

[0002] In recent years, with the rapid development of biometric identification technology, fingerprint recognition has been widely used in identity authentication field due to its unique convenience and security. The traditional fingerprint acquisition method often relies on single-finger pressing, which is not only low in efficiency, but also may cause poor quality of the acquired fingerprint image in some scenarios due to finger stains, damage or different dryness and wetness levels, affecting the subsequent recognition accuracy. In order to improve the speed and reliability of fingerprint verification, double-finger simultaneous acquisition of fingerprint information has become a new technical trend. How to efficiently and stably acquire high-quality double-finger fingerprint images has become an important research direction in current fingerprint recognition technology.

[0003] In the prior art, on the one hand, the initial adjustment of the illumination light source depends on fixed parameter settings, which is difficult to adapt to different user finger skin conditions and environmental light changes, and is prone to problems of insufficient light intensity and light angle deviation, resulting in reduced contrast of fingerprint ridges and valleys, affecting image quality. On the other hand, there is a lack of real-time monitoring and dynamic adjustment mechanism for light abnormalities during the acquisition process. When the double-finger pressing state or the performance of the light source itself changes slightly, the illumination parameters cannot be corrected in time, making the acquired fingerprint image prone to blurring and loss of details. The evaluation standard for the quality of the fingerprint image is single and cannot fully reflect the effectiveness of the fingerprint image. SUMMARY

[0004] The technical problem solved by the present application is that the initial adjustment of the illumination light source depends on fixed parameter settings, which is difficult to adapt to different user finger skin conditions and environmental light changes, and is prone to problems of insufficient light intensity and light angle deviation, resulting in reduced contrast of fingerprint ridges and valleys, affecting image quality. On the other hand, there is a lack of real-time monitoring and dynamic adjustment mechanism for light abnormalities during the acquisition process. When the double-finger pressing state or the performance of the light source itself changes slightly, the illumination parameters cannot be corrected in time, making the acquired fingerprint image prone to blurring and loss of details. The evaluation standard for the quality of the fingerprint image is single and cannot fully reflect the effectiveness of the fingerprint image.

[0005] To solve the above technical problems, the present application provides the following technical solution: a fingerprint verification method based on double-finger fingerprint image acquisition, comprising the following steps:

[0006] Step S1, deploying a light sensor;

[0007] Step S2, adjusting the illumination light source once;

[0008] Step S3, collecting light intensity data of the fingerprint surface when the two fingers are pressed by the light sensor respectively;

[0009] Step S4, judging the abnormal situation according to the light intensity data, and performing secondary adjustment on the illumination light source;

[0010] Step S5, collecting the fingerprint image of the two fingers, and judging whether the fingerprint image quality meets the standard, if not, repeatedly adjusting the illumination light source until the fingerprint image quality meets the standard.

[0011] As a preferred scheme of the fingerprint verification method based on the two-finger fingerprint image collection of the application, the step S1 specifically comprises:

[0012] Two symmetrical trapezoidal prisms are arranged, and light sensors are arranged on the upper surfaces of the two trapezoidal prisms, respectively, the light sensors are used to collect the light intensity scattered by the fingerprint surface, and the light intensity data is obtained, the light intensity data includes the fingerprint ridge light intensity and the fingerprint valley light intensity.

[0013] As a preferred scheme of the fingerprint verification method based on the two-finger fingerprint image collection of the application, the step S2 specifically comprises:

[0014] The adjustment module is used to perform primary adjustment on the illumination light source, the adjustment module includes illumination light source intensity adjustment and illumination light source angle adjustment;

[0015] The illumination light source intensity adjustment is performed by changing the power supply current of the illumination light source through a controllable resistance circuit to adjust the illumination light source intensity until the illumination light source intensity reaches the preset value;

[0016] The illumination light source angle adjustment is performed by fixing the illumination light source on a rotating support, adjusting the angle of the illumination light source through the rotating support until the light of the illumination light source enters the trapezoidal prism and does not deviate from the preset transmission path.

[0017] As a preferred scheme of the fingerprint verification method based on the two-finger fingerprint image collection of the application, the step S3 specifically comprises:

[0018] When the user presses the two fingers on the upper surfaces of the two trapezoidal prisms respectively, the first illumination light source emits the first light, the first light is transmitted to the first fingerprint surface through the first trapezoidal prism to generate the first scattering, the light intensity of the first scattering is collected by the light sensor to obtain the first light intensity data, the first light intensity data includes the first fingerprint ridge light intensity and the first fingerprint valley light intensity;

[0019] Meanwhile, the second light source emits second light, and the second light is transmitted to the second fingerprint surface through the second trapezoidal prism to generate second scattering, the light intensity of the second scattering is collected by the light sensor, and second light intensity data is obtained, the second light intensity data includes second fingerprint ridge line light intensity and second fingerprint valley line light intensity;

[0020] The first light intensity and the second light intensity are compared, and a difference value is obtained.

[0021] As a preferred scheme of the fingerprint verification method based on double-finger fingerprint image acquisition, the step S4 specifically comprises:

[0022] The difference value is received, whether the light source is abnormal is judged according to the difference value, and the light source is secondarily adjusted according to the abnormal condition, and the abnormal condition includes insufficient light source intensity and improper light source angle.

[0023] As a preferred scheme of the fingerprint verification method based on double-finger fingerprint image acquisition, the step S4 specifically comprises:

[0024] When the difference value is less than or equal to the first threshold value, it is determined that the light source is not abnormal;

[0025] When the difference value is greater than the first threshold value, it is determined that the light source is abnormal, and further, if the intensity of one side light source is less than the second threshold value, it is determined that the light source intensity is insufficient;

[0026] If the intensity of both sides of the light source is greater than or equal to the second threshold value and less than the third threshold value, it is determined that the light source angle is improper.

[0027] As a preferred scheme of the fingerprint verification method based on double-finger fingerprint image acquisition, the step S4 specifically comprises:

[0028] If it is determined that the light source intensity is insufficient, the power supply current of the light source on this side is changed through a controllable resistance circuit to improve the intensity of the light source on this side, until the intensity of the light source on this side is greater than or equal to the second threshold value and less than the third threshold value;

[0029] If it is determined that the light source angle is improper, the angle of the light source on this side is adjusted through a rotating support, and the first light intensity and the second light intensity after adjustment are collected in real time, the difference value after adjustment is obtained, until the difference value after adjustment is less than or equal to the first threshold value, and the angle adjustment is stopped.

[0030] As a preferred embodiment of the fingerprint verification method based on dual-fingerprint image acquisition described in this invention, step S5 specifically includes:

[0031] The system acquires the light emitted from the adjusted illumination source, transmits the light through a trapezoidal prism to the surface of the two-finger fingerprint, scatters the light, and captures the scattered light. The scattered light is then emitted through the waist face of the trapezoidal prism, and the emitted light is reflected by a mirror, capturing the reflected light. A camera receives the reflected light to acquire a fingerprint image of the two fingers. A sharpness detection algorithm is used to assess the quality of the fingerprint image to determine if it meets the standards. If the fingerprint image quality does not meet the standards, the illumination source is readjusted once and then again, and the camera captures fingerprint images until the quality of the fingerprint images captured by the camera meets the set standards.

[0032] As a preferred embodiment of the fingerprint verification method based on dual-fingerprint image acquisition described in this invention, the step of performing a quality assessment on the fingerprint image to determine whether the fingerprint image quality meets the standard specifically includes:

[0033] The quality assessment includes edge sharpness assessment and effective area percentage assessment;

[0034] Edge sharpness assessment: In the fingerprint image, fingerprint ridges correspond to bright areas and fingerprint valleys correspond to dark areas. The pixel grayscale values ​​of the fingerprint image are obtained, and the rate of change of the pixel grayscale values ​​is calculated by a gradient operator. If the rate of change of the pixel grayscale value at the intersection of the fingerprint ridge and the fingerprint valley is greater than or equal to a preset sharpness threshold, and the pixel grayscale difference between adjacent fingerprint ridges and fingerprint valleys is greater than or equal to a preset contrast threshold, then the edge sharpness is determined to meet the standard.

[0035] Effective area proportion assessment: Based on the imaging range of the upper surface of the trapezoidal prism, obtain the pixel grayscale value of the fingerprint image, calculate the proportion of the pixel grayscale value that is in the preset pixel grayscale value range of the fingerprint ridge and fingerprint valley. If the proportion is greater than or equal to the preset area threshold, and the number of pixels in the fingerprint image that exceed the preset pixel grayscale value range due to uneven illumination is less than or equal to the preset pixel value, then the effective area proportion is determined to meet the standard.

[0036] A fingerprint verification device based on two-finger fingerprint image acquisition includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor performs the fingerprint verification method based on two-finger fingerprint image acquisition.

[0037] The beneficial effects of this invention are as follows: By deploying a light sensor and constructing a closed-loop adjustment mechanism of primary adjustment, secondary adjustment, and quality feedback, this invention achieves dynamic monitoring and precise control of the illumination source. This effectively solves the problem in existing technologies where fixed parameter adjustments are difficult to adapt to changes in finger condition and ambient light. The light sensor collects real-time light intensity data from the surface of the two-finger fingerprint, and combined with secondary adjustment, it specifically corrects anomalies such as insufficient light intensity or improper angle, reducing image blurring and detail loss caused by lighting issues. The two-finger acquisition design improves the accuracy of anomaly detection through mutual reference of two-finger data, reduces the impact of single-finger anomalies on verification results, and enhances anti-counterfeiting performance. The image quality evaluation standard, combining edge sharpness and effective area ratio, ensures that the acquired image contains sufficient feature information, improving the stability and effectiveness of fingerprint image quality. This provides reliable data support for two-finger fingerprint verification, improving the accuracy and practical application effect of fingerprint verification. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the basic process of a fingerprint verification method based on two-finger fingerprint image acquisition, provided as an embodiment of the present invention. Detailed Implementation

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0040] Example, refer to Figure 1 As an embodiment of the present invention, a fingerprint verification method based on two-finger fingerprint image acquisition is provided, comprising the following steps:

[0041] Step S1: Deploy the light sensor.

[0042] Step S2: Adjust the lighting source once.

[0043] Step S3: Collect light intensity data of the fingerprint surface when two fingers are pressed using a light sensor.

[0044] Step S4: Based on the light intensity data, determine the abnormal situation and make secondary adjustments to the lighting source.

[0045] Step S5: Collect fingerprint images of two fingers and determine whether the fingerprint image quality meets the standard. If it does not meet the standard, repeatedly adjust the illumination source until the fingerprint image quality meets the standard.

[0046] Step S1 specifically includes:

[0047] Two symmetrical trapezoidal prisms are deployed, and light sensors are deployed on the upper surface edges of the two trapezoidal prisms respectively. The light sensors are used to collect the light intensity after the fingerprint surface is scattered, and to obtain light intensity data, including the light intensity of the fingerprint ridges and the light intensity of the fingerprint valleys.

[0048] Two symmetrical trapezoidal prisms are deployed to ensure the consistency of the two-finger fingerprint acquisition environment through the symmetrical structure, providing a reliable benchmark for comparing the light intensity data of the two fingers. Light sensors are deployed on the upper surface edges of the two trapezoidal prisms to maximize the reception of scattered light from the fingerprint surface, ensuring that the acquired light intensity data can truly reflect the fingerprint texture features.

[0049] Step S1 uses a light sensor to collect the intensity of light scattered from the fingerprint surface. It can accurately capture the difference in light intensity between the fingerprint ridges and valleys due to their different shapes, and obtain key data including the light intensity of the ridges and valleys. This provides a direct basis for judging whether there is an abnormality in the lighting source. By comparing the light intensity data of two fingers, problems such as unilateral light source or finger pressing can be quickly identified, providing a precise direction for subsequent lighting adjustment.

[0050] Step S2 specifically includes:

[0051] The lighting source is adjusted using the adjustment module, which includes adjusting the intensity and angle of the lighting source.

[0052] The lighting source can be adjusted once using the adjustment module. With the adjustment module covering the adjustment of the lighting source intensity and angle, a lighting environment that meets basic standards can be provided at the initial stage of two-finger fingerprint collection.

[0053] Lighting intensity adjustment: The intensity of the lighting source is adjusted by changing the power supply current of the lighting source through a controllable resistor circuit until the intensity of the lighting source reaches the preset value.

[0054] Light source angle adjustment: Fix the light source on the rotating bracket and adjust the angle of the light source by rotating the bracket until the light from the light source enters the trapezoidal prism and does not deviate from the preset transmission path.

[0055] The intensity of the lighting source can be adjusted by changing the power supply current through a controllable resistor circuit, which can quickly stabilize the intensity of the light source at the preset value and ensure that the light energy meets the fingerprint scattering requirements. The angle of the lighting source can be adjusted by fixing the lighting source with a rotating bracket and adjusting the angle, which can ensure that the light accurately enters the trapezoidal prism and propagates along the preset transmission path, reducing light loss and deviation.

[0056] Step S2 not only lays the foundation for the subsequent acquisition of valid data by the light sensor, but also avoids fingerprint image quality problems caused by improper initial lighting, thereby improving the stability and reliability of two-finger fingerprint acquisition from the source.

[0057] Step S3 specifically includes:

[0058] When a user presses two fingers onto the upper surfaces of the two trapezoidal prisms respectively, the first illumination source emits a first light, which is transmitted through the first trapezoidal prism to the surface of the first fingerprint and undergoes first scattering. The intensity of the first scattered light is collected by the light sensor to obtain the first light intensity data, which includes the light intensity of the first fingerprint ridge and the light intensity of the first fingerprint valley.

[0059] Simultaneously, the second illumination source emits a second light, which is transmitted through the second trapezoidal prism to the surface of the second fingerprint, causing a second scattering. The intensity of the second scattered light is collected by the light sensor to obtain the second light intensity data, which includes the light intensity of the second fingerprint ridge and the light intensity of the second fingerprint valley.

[0060] The intensity of the first light ray and the intensity of the second light ray are compared, and the difference between the two is obtained.

[0061] By simultaneously acquiring and comparing data from two fingers, the texture features of two fingerprints (the light difference between fingerprint ridges and valleys) can be captured separately. This allows the light intensity data of fingerprint ridges and valleys to truly reflect fingerprint features, laying the foundation for quality control of subsequent image acquisition. Furthermore, the difference values ​​can be used to intuitively reflect the consistency of the two-finger acquisition environment (such as whether the intensity and angle of the light sources on both sides are symmetrical), providing a quantitative basis for subsequent judgment of abnormal lighting sources. At the same time, the parallel design of dual lighting sources improves data acquisition efficiency and ensures the synchronization of two-finger information.

[0062] The corresponding arrangement of dual illumination sources and dual trapezoidal prisms ensures the independence and symmetry of the two-finger sampling conditions, avoiding mutual interference.

[0063] Step S4 specifically includes:

[0064] The system receives the difference value, determines whether there is an abnormality in the lighting source based on the difference value, and makes secondary adjustments to the lighting source based on the abnormality. Abnormalities include insufficient lighting intensity and improper lighting angle.

[0065] By analyzing the difference values, we can accurately locate the abnormality of the lighting source (insufficient intensity or improper angle), and then implement corresponding adjustment measures to avoid the degradation of fingerprint image quality due to light source problems. This ensures the consistency and stability of the two-finger fingerprint acquisition conditions and provides a guarantee for the acquisition of high-quality fingerprint images.

[0066] Determining whether a lighting source is malfunctioning based on the difference value specifically includes:

[0067] When the difference value is less than or equal to the first threshold, it is determined that there is no abnormality in the lighting source.

[0068] When the difference value is greater than the first threshold, it is determined that there is an abnormality in the lighting source. Furthermore, if the intensity of the lighting source on one side is less than the second threshold, it is determined that the intensity of the lighting source is insufficient.

[0069] If the intensity of the lighting sources on both sides is greater than or equal to the second threshold and less than the third threshold, it is determined that the angle of the lighting source is inappropriate.

[0070] A clear logic for judging abnormal lighting sources has been established, providing quantitative standards for evaluating differences and light source intensity, and enabling precise differentiation of whether a light source is abnormal.

[0071] The secondary adjustment of the lighting source in response to abnormal conditions specifically includes:

[0072] If the intensity of the lighting source is determined to be insufficient, the power supply current of the lighting source on that side is changed through a controllable resistor circuit to increase the intensity of the lighting source on that side until the intensity of the lighting source on that side is greater than or equal to the second threshold and less than the third threshold.

[0073] If the angle of the lighting source is determined to be improper, the angle of the lighting source on that side is adjusted by rotating the bracket, and the first light intensity and the second light intensity after adjustment are collected in real time to obtain the difference value after adjustment. The angle adjustment is stopped when the difference value after adjustment is less than or equal to the first threshold.

[0074] For insufficient illumination intensity, the power supply current is adjusted by a controllable resistor circuit to control the illumination intensity within a specific threshold range, ensuring sufficient light conditions to clearly distinguish fingerprint ridges and valleys. For improper illumination angle, the difference value is adjusted and monitored using a rotating bracket to correct the light path deviation, ensuring a symmetrical dual-finger acquisition environment. This provides stable light support for high-quality dual-finger fingerprint image acquisition, effectively addressing light source issues and improving the accuracy of fingerprint acquisition.

[0075] Step S5 specifically includes:

[0076] The system acquires the light emitted from the adjusted illumination source, transmits it through a trapezoidal prism to the surface of the two fingerprints, causing scattering, and captures the scattered light. The scattered light is then emitted through the waist of the trapezoidal prism, and the emitted light is reflected by a mirror, capturing the reflected light. A camera receives the reflected light, acquiring the fingerprint image of the two fingers. A sharpness detection algorithm is used to assess the quality of the fingerprint image, determining whether it meets the standards. If the fingerprint image quality does not meet the standards, the illumination source is readjusted once and then again, and the camera captures fingerprint images again until the quality of the fingerprint images captured by the camera meets the set standards.

[0077] The exit design of the trapezoidal prism waist surface, in conjunction with the reflector, optimizes the optical path and adapts to the camera's installation position. Using a sharpness detection algorithm, the fingerprint image quality is assessed, which works in conjunction with light adjustment. Through multiple iterations, the image quality is ensured to be stable and up to standard, preventing inferior images caused by accidental factors from entering the verification process.

[0078] By using a standardized optical path transmission design, fingerprint scattered light is efficiently transmitted to the camera. Combined with a quality assessment and closed-loop adjustment mechanism, high-quality fingerprint images that meet the standards are finally obtained, providing reliable data for subsequent verification.

[0079] The quality assessment of fingerprint images, determining whether the fingerprint image quality meets the standards, specifically includes:

[0080] The quality assessment includes edge sharpness assessment and effective area percentage assessment.

[0081] Edge sharpness assessment: Fingerprint ridges correspond to bright areas and fingerprint valleys correspond to dark areas in the fingerprint image. Obtain the pixel grayscale values ​​of the fingerprint image and calculate the rate of change of pixel grayscale values ​​using a gradient operator. If the rate of change of pixel grayscale values ​​at the intersection of fingerprint ridges and fingerprint valleys is greater than or equal to a preset sharpness threshold, and the pixel grayscale difference between adjacent fingerprint ridges and fingerprint valleys is greater than or equal to a preset contrast threshold, then the edge sharpness is determined to meet the standard.

[0082] The clarity of fingerprint texture edges was precisely quantified—when the gray-scale change rate at the boundary and the gray-scale difference between adjacent ridges and valleys both meet the standard, it indicates that the fingerprint edges are clear and the texture is highly distinguishable, providing a good foundation for subsequent fingerprint feature extraction.

[0083] Effective area proportion assessment: Based on the imaging range of the upper surface of the trapezoidal prism, obtain the pixel grayscale value of the fingerprint image, calculate the proportion of pixel grayscale values ​​that are in the preset pixel grayscale value range of the fingerprint ridge and fingerprint valley. If the proportion is greater than or equal to the preset area threshold, and the pixels in the fingerprint image that are outside the preset pixel grayscale value range due to uneven illumination are less than or equal to the preset pixel value, then the effective area proportion is determined to meet the standard.

[0084] A comprehensive assessment of the coverage and integrity of the effective texture area in a fingerprint image—when the proportion of effective pixels meets the standard and the invalid pixels caused by uneven illumination are within a reasonable range, it indicates that there is sufficient fingerprint information in the image that can be used for verification, reducing feature loss caused by insufficient effective area or illumination problems.

[0085] A fingerprint verification device based on two-finger fingerprint image acquisition includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor performs a fingerprint verification method based on two-finger fingerprint image acquisition.

[0086] This invention achieves dynamic monitoring and precise control of the lighting source by deploying a light sensor and constructing a closed-loop adjustment mechanism consisting of primary adjustment, secondary adjustment, and quality feedback. This effectively solves the problem in existing technologies where fixed parameter adjustments are difficult to adapt to changes in finger position and ambient light. The light sensor collects real-time light intensity data from the surface of the two-finger fingerprint, and the secondary adjustment specifically corrects anomalies such as insufficient light intensity or improper angle, reducing image blurring and detail loss caused by lighting issues. The two-finger acquisition design improves the accuracy of anomaly detection through cross-referencing of two-finger data, reduces the impact of single-finger anomalies on verification results, and enhances anti-counterfeiting performance. The image quality evaluation standard, combining edge sharpness and effective area proportion, ensures that the acquired image contains sufficient feature information, improving the stability and effectiveness of fingerprint image quality. This provides reliable data support for two-finger fingerprint verification, improving the accuracy and practical application effect of fingerprint verification.

[0087] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0088] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A fingerprint verification method based on two-fingerprint image acquisition, characterized in that, Includes the following steps: Step S1: Deploy the light sensor; Step S2: Adjust the lighting source once; Step S3: Collect light intensity data of the fingerprint surface when two fingers are pressed using the light sensor; Step S4: Based on the light intensity data, determine the abnormal situation and make secondary adjustments to the lighting source; Step S5: Collect fingerprint images of two fingers and determine whether the quality of the fingerprint image meets the standard. If it does not meet the standard, repeatedly adjust the illumination source until the quality of the fingerprint image meets the standard.

2. The fingerprint verification method based on dual-fingerprint image acquisition as described in claim 1, characterized in that: Step S1 specifically includes: Two symmetrical trapezoidal prisms are deployed, and light sensors are deployed on the upper surface edges of the two trapezoidal prisms respectively. The light sensors are used to collect the light intensity after the fingerprint surface is scattered, and obtain light intensity data, which includes the light intensity of the fingerprint ridges and the light intensity of the fingerprint valleys.

3. The fingerprint verification method based on dual-fingerprint image acquisition as described in claim 1, characterized in that: Step S2 specifically includes: The lighting source is adjusted once using an adjustment module, which includes lighting source intensity adjustment and lighting source angle adjustment. Lighting intensity adjustment: The intensity of the lighting source is adjusted by changing the power supply current of the lighting source through a controllable resistor circuit until the intensity of the lighting source reaches a preset value; Light source angle adjustment: Fix the light source on the rotating bracket, and adjust the angle of the light source by rotating the bracket until the light from the light source enters the trapezoidal prism and does not deviate from the preset transmission path.

4. The fingerprint verification method based on dual-fingerprint image acquisition as described in claim 1, characterized in that: Step S3 specifically includes: When a user presses two fingers onto the upper surfaces of the two trapezoidal prisms respectively, the first illumination source emits a first light, which is transmitted through the first trapezoidal prism to the surface of the first fingerprint and undergoes a first scattering. The intensity of the first scattered light is collected by the light sensor to obtain the first light intensity data, which includes the light intensity of the first fingerprint ridge and the light intensity of the first fingerprint valley. Simultaneously, the second illumination source emits a second light, which is transmitted through the second trapezoidal prism to the surface of the second fingerprint, causing a second scattering. The intensity of the second scattered light is collected by the light sensor to obtain second light intensity data, which includes the light intensity of the second fingerprint ridge and the light intensity of the second fingerprint valley. The intensity of the first light and the intensity of the second light are compared, and the difference between the two is obtained.

5. The fingerprint verification method based on dual-fingerprint image acquisition as described in claim 1, characterized in that: Step S4 specifically includes: The system receives a difference value, determines whether the lighting source is abnormal based on the difference value, and makes secondary adjustments to the lighting source based on the abnormality. The abnormality includes insufficient lighting intensity and improper lighting angle.

6. The fingerprint verification method based on dual-fingerprint image acquisition as described in claim 5, characterized in that: The step of determining whether the lighting source is abnormal based on the difference value specifically includes: When the difference value is less than or equal to the first threshold, it is determined that the lighting source is not abnormal; When the difference value is greater than the first threshold, it is determined that the lighting source is abnormal. Furthermore, if the intensity of the lighting source on one side is less than the second threshold, it is determined that the intensity of the lighting source is insufficient. If the intensity of the lighting sources on both sides is greater than or equal to the second threshold and less than the third threshold, it is determined that the angle of the lighting source is inappropriate.

7. The fingerprint verification method based on dual-fingerprint image acquisition as described in claim 5, characterized in that: The step of performing secondary adjustment of the lighting source based on the abnormal situation specifically includes: If the intensity of the lighting source is determined to be insufficient, the power supply current of the lighting source on that side is changed through a controllable resistor circuit to increase the intensity of the lighting source on that side until the intensity of the lighting source on that side is greater than or equal to the second threshold and less than the third threshold. If the angle of the lighting source is determined to be improper, the angle of the lighting source on that side is adjusted by rotating the bracket, and the first light intensity and the second light intensity after adjustment are collected in real time to obtain the difference value after adjustment. The angle adjustment is stopped when the difference value after adjustment is less than or equal to the first threshold.

8. The fingerprint verification method based on dual-fingerprint image acquisition as described in claim 1, characterized in that: Step S5 specifically includes: The system acquires the light emitted from the adjusted illumination source, transmits the light through a trapezoidal prism to the surface of the two-finger fingerprint, scatters the light, and captures the scattered light. The scattered light is then emitted through the waist face of the trapezoidal prism, and the emitted light is reflected by a mirror, capturing the reflected light. A camera receives the reflected light to acquire a fingerprint image of the two fingers. A sharpness detection algorithm is used to assess the quality of the fingerprint image to determine if it meets the standards. If the fingerprint image quality does not meet the standards, the illumination source is readjusted once and then again, and the camera captures fingerprint images until the quality of the fingerprint images captured by the camera meets the set standards.

9. The fingerprint verification method based on dual-fingerprint image acquisition as described in claim 8, characterized in that: The step of performing a quality assessment on the fingerprint image to determine whether the fingerprint image quality meets the standards specifically includes: The quality assessment includes edge sharpness assessment and effective area percentage assessment; Edge sharpness assessment: In the fingerprint image, fingerprint ridges correspond to bright areas and fingerprint valleys correspond to dark areas. The pixel grayscale values ​​of the fingerprint image are obtained, and the rate of change of the pixel grayscale values ​​is calculated by a gradient operator. If the rate of change of the pixel grayscale value at the intersection of the fingerprint ridge and the fingerprint valley is greater than or equal to a preset sharpness threshold, and the pixel grayscale difference between adjacent fingerprint ridges and fingerprint valleys is greater than or equal to a preset contrast threshold, then the edge sharpness is determined to meet the standard. Effective area proportion assessment: Based on the imaging range of the upper surface of the trapezoidal prism, obtain the pixel grayscale value of the fingerprint image, calculate the proportion of the pixel grayscale value that is in the preset pixel grayscale value range of the fingerprint ridge and fingerprint valley. If the proportion is greater than or equal to the preset area threshold, and the number of pixels in the fingerprint image that exceed the preset pixel grayscale value range due to uneven illumination is less than or equal to the preset pixel value, then the effective area proportion is determined to meet the standard.

10. A fingerprint verification device based on dual-fingerprint image acquisition, characterized in that: The device includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the fingerprint verification method based on two-finger fingerprint image acquisition as described in any one of claims 1-9.

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