Optical ultrasonic collaborative fingerprint identification device and identification method

Abstract

The invention relates to the technical field of fingerprint identification, in particular to an optical ultrasonic collaborative fingerprint identification device and an identification method. According to the device, efficient recognition is achieved through a dynamic switching mechanism, the optical module obtains fingerprint surface images, the ultrasonic module can penetrate through a water film and stains, the failure problem in a humid and dirty scene is solved, the image detection module evaluates the optical image quality in real time and monitors finger humidity, and when the image quality is lower than a threshold value or the humidity exceeds the standard, the fingerprint recognition module is started. And automatically triggering an ultrasonic mode. And the verification module uses the ultrasonic three-dimensional features for correction when optical identification is inaccurate, and calls historical optical data for compensation to form a dual-guarantee mechanism when the ultrasonic features are incomplete. According to the device, multi-scene coverage is realized through environment perception and intelligent decision, the anti-counterfeiting safety is enhanced through dual biological characteristic verification, a dynamic switching mechanism ensures that a user can complete identification through one-time contact, repeated adjustment operation is not needed, and a high-reliability identity authentication solution is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of fingerprint recognition, and in particular to an optical and ultrasonic collaborative fingerprint recognition device and recognition method. Background Art

[0002] With the wide application of biometric technologies, fingerprint recognition has become an important means of identity authentication in scenarios such as outdoor working devices and security terminals. The existing fingerprint recognition technologies mainly include three schemes: capacitive, optical, and ultrasonic, and each scheme has its unique advantages and disadvantages.

[0003] First of all, capacitive fingerprint recognition technology relies on physical contact to collect fingerprint images. Although this method has high recognition accuracy, it is easily interfered by sweat. Especially in high-temperature and high-humidity environments, the user's fingerprint may not be accurately recognized due to the presence of sweat. The capacitive sensor is also not very friendly to overly dry fingers, which may lead to recognition failure.

[0004] Secondly, optical fingerprint recognition technology has been widely used in outdoor devices due to its high cost performance and anti-static characteristics. This technology captures fingerprint images through visible light reflection imaging, so the recognition effect is very good when the finger surface is clean. However, when there is water stain, oil stain or dirt on the finger surface, the reflected light signal will be severely attenuated, resulting in a significant increase in the recognition failure rate, which is particularly common in outdoor environments because it is difficult for users' fingers to always remain clean.

[0005] Finally, ultrasonic fingerprint recognition technology obtains the three-dimensional structure information of fingerprints by emitting ultrasonic waves to penetrate the skin surface layer. This method has the advantages of anti-moisture and dirt and supporting live detection, and can still maintain high recognition accuracy when there is a small amount of stain on the finger surface. However, the penetration ability of ultrasonic signals is affected by the thickness of the finger cutin layer. For people engaged in outdoor work for a long time, their finger cutin layers are usually relatively thick, which will cause attenuation of ultrasonic signals and thus affect the recognition accuracy. Summary of the Invention

[0006] (I) Technical Problems to be Solved The present invention provides an optical and ultrasonic collaborative fingerprint recognition device and recognition method to overcome the problems in the prior art that fingerprint recognition is affected by high humidity and low-quality images, and there are limitations in single optical or ultrasonic recognition technologies.

[0007] (II) Technical Solutions To achieve the above object, on the one hand, the present invention provides an optical and ultrasonic collaborative fingerprint recognition device, including: an optical acquisition module, an ultrasonic acquisition module, an image detection module, a verification module, and a control and processing module; The verification module is respectively connected to the optical acquisition module, the image detection module, and the ultrasonic acquisition module; The image detection module is connected to the control processing module, and the other end of the control processing module is connected to the ultrasonic acquisition module; The optical acquisition module is used to obtain the optical image of the fingerprint; The ultrasonic acquisition module is used to obtain the three-dimensional ultrasonic image of the user's fingerprint; The image detection module includes an image quality evaluation unit and a humidity detection unit; The verification module is used to store the preset fingerprint template and perform identification and comparison.

[0008] Preferably, the image quality evaluation unit is used to evaluate the quality of the fingerprint optical image obtained by the optical acquisition module. When the evaluation result of the image quality evaluation unit indicates that the quality of the optical image is lower than the preset quality threshold, the control processing module controls the activation of the ultrasonic acquisition module to collect the fingerprint image.

[0009] Preferably, the humidity detection unit is used to detect the humidity on the surface of the finger. When the detected humidity on the surface of the finger is higher than the preset humidity threshold, the control processing module controls the activation of the ultrasonic acquisition module to collect the fingerprint image.

[0010] Preferably, the verification module is used to respectively perform identification and comparison on the fingerprint optical image obtained by the optical acquisition module and the three-dimensional ultrasonic image obtained by the ultrasonic acquisition module with the preset fingerprint template, and output the identification result information according to the comparison result.

[0011] Preferably, when the identification and comparison result of the optical image is inaccurate, the verification module uses the identification and comparison result of the three-dimensional ultrasonic image to correct and compensate the identification and comparison result of the optical image, so as to improve the accuracy of fingerprint identification.

[0012] Preferably, the optical acquisition module includes an illumination lamp, an optical lens, and an image sensor. The illumination lamp is used to illuminate the finger fingerprint, the optical lens is used to focus the fingerprint image on the image sensor, and the image sensor is used to convert the optical image into an electrical signal and transmit it to the verification module.

[0013] Preferably, the ultrasonic acquisition module includes an ultrasonic transmitting probe and an ultrasonic receiving probe. The ultrasonic transmitting probe is used to transmit ultrasonic waves to the finger, and the ultrasonic receiving probe is used to receive the reflected ultrasonic wave signal and convert it into three-dimensional ultrasonic image data and transmit it to the verification module.

[0014] On the other hand, the present invention also provides a recognition method for an optical and ultrasonic collaborative fingerprint recognition device, including: Step S1: After the device is started, the finger contact state is detected in real time by the image detection module. When finger contact is detected, the optical acquisition module is triggered to perform initial image acquisition. Step S2: The image quality evaluation unit scores the quality of the optical image, and at the same time, the humidity detection unit synchronously detects the humidity on the finger surface. Step S3: If the quality of the optical image is lower than the preset threshold or the humidity is higher than the preset threshold, the control processing module is controlled to switch to the ultrasonic acquisition mode. If the quality of the optical image meets the standard and the humidity is normal, the optical acquisition mode is maintained. Step S4: The verification module extracts and verifies the feature of the image data obtained by the two modes. Step S5: When it is detected that the ultrasonic image feature is incomplete, the optical fingerprint data of the relevant historical fingerprint record is called according to the collected feature points for feature compensation, and secondary verification is performed after compensation.

[0015] (III) Beneficial effects The present invention provides an optical and ultrasonic collaborative fingerprint recognition device and a recognition method, which can realize real-time monitoring of the finger surface state through the humidity detection unit and the image quality evaluation unit. When high humidity or insufficient optical image quality is detected, it automatically switches to the ultrasonic mode. Ultrasonic waves can penetrate the water film and stains to obtain the three-dimensional structure information of the fingerprint, effectively solving the problem of the failure of traditional optical sensors in humid and dirty environments. The optical acquisition has a fast speed and low cost, and is suitable for daily scenarios. The ultrasonic wave has strong anti-interference ability and is suitable for complex environments. The two work together to cover more usage scenarios and can significantly improve the robustness of the system. When the recognition result of the optical recognition is inaccurate, the verification module uses the three-dimensional image data of the ultrasonic wave to correct the feature, reducing the misjudgment caused by surface damage or stains. In addition, when the ultrasonic image feature is incomplete, the historical optical data is called to compensate for the missing information, forming a double guarantee mechanism. The subcutaneous biometric features collected by ultrasonic waves are difficult to be counterfeited by two-dimensional forgery means. Combined with the double verification of the optical surface layer, the anti-counterfeiting security is greatly improved. The dynamic switching mechanism ensures that the user can complete the recognition with one contact, without repeatedly adjusting the finger position or wiping the surface due to environmental problems, and the operation is more convenient. Thus, through the environmental perception, multi-modal data fusion and intelligent decision-making mechanism, the limitation problem of traditional single-technology fingerprint recognition in complex scenarios is solved. Description of the drawings

[0016] Figure 1 Shows the structural schematic diagram of an optical and ultrasonic collaborative fingerprint recognition device of the present invention; Figure 2 Shows the flow chart of the recognition method of an optical and ultrasonic collaborative fingerprint recognition device of the present invention. Detailed implementation manners

[0017] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0018] In the description of the present invention, it is necessary to understand that the orientation or positional relationships indicated by "upper", "lower", "left", "right", "inner", "outer", "top", "bottom", etc. are all based on the orientation or positional relationships shown in the accompanying drawings. The purpose is only to facilitate the description of the present invention and simplify the description, rather than indicating or implying that the components referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0019] As Figure 1-2 shown, the present invention provides an optical and ultrasonic collaborative fingerprint recognition device, including: an optical acquisition module, an ultrasonic acquisition module, an image detection module, a verification module, and a control and processing module; The present invention provides an optical and ultrasonic collaborative fingerprint recognition device, including: an optical acquisition module, an ultrasonic acquisition module, an image detection module, a verification module, and a control and processing module; The verification module is respectively connected to the optical acquisition module, the image detection module, and the ultrasonic acquisition module. The image detection module is connected to the control and processing module, and the other end of the control and processing module is connected to the ultrasonic acquisition module; The optical acquisition module is used to obtain an optical image of the fingerprint. The optical acquisition module includes an illumination lamp, an optical lens, and an image sensor. The illumination lamp adopts a multi-spectral LED array and can automatically adjust the color temperature and illuminance according to the ambient light intensity to ensure the optimization of the contrast between fingerprint ridges and valleys. The optical lens has a dynamic focusing function. The optical lens is used to focus the fingerprint image onto the image sensor. The optical lens realizes millimeter-level precise focusing through a microelectromechanical system drive. The image sensor adopts back-illuminated CMOS technology. The image sensor is used to convert the optical image into an electrical signal and transmit it to the verification module.

[0020] The ultrasonic acquisition module is used to obtain a three-dimensional ultrasonic image of the user's fingerprint. The ultrasonic acquisition module includes a phased array ultrasonic transmitting probe and a matrix ultrasonic receiving probe. The ultrasonic transmitting probe is used to transmit ultrasonic waves to the finger. The ultrasonic receiving probe is used to receive the reflected ultrasonic wave signal and convert it into three-dimensional ultrasonic image data and transmit it to the verification module.

[0021] The image detection module includes an image quality assessment unit and a humidity detection unit. The image quality assessment unit uses a convolutional neural network algorithm to analyze the clarity, integrity, and noise level of the image in real time. When the assessment result indicates that the optical image quality is lower than the preset quality threshold, the control processing module is automatically triggered to start the ultrasonic acquisition module. The humidity detection unit is based on a capacitive humidity sensor array and is used to detect the humidity on the finger surface. When the detected humidity on the finger surface is higher than the preset humidity threshold and the fingerprint verification using the optical acquisition module fails, the control processing module controls the start of the ultrasonic acquisition module to collect fingerprint images for secondary verification; When the optical image recognition and comparison result is inaccurate, the verification module uses the three-dimensional ultrasonic image recognition and comparison result to correct the optical image recognition and comparison result to improve the accuracy of fingerprint recognition. When both the ultrasonic image and the optical image cannot be successfully verified, compensation and correction are performed through the ultrasonic image and the optical image, and the verification points of the two are superimposed. If the set requirements are met, successful verification can be performed.

[0022] The verification module is used to store the preset fingerprint template and perform recognition and comparison. The verification module is used to separately recognize and compare the fingerprint optical image obtained by the optical acquisition module and the three-dimensional ultrasonic image obtained by the ultrasonic acquisition module with the preset fingerprint template, and output the recognition result information according to the comparison result.

[0023] The actual working scenario of an optical-ultrasonic collaborative fingerprint recognition device is introduced in detail below.

[0024] The present invention provides a recognition method for an optical-ultrasonic collaborative fingerprint recognition device, including: Step S1, after the device is started, the finger contact state is detected in real time through the image detection module. When finger contact is detected, the optical acquisition module is triggered to perform initial image acquisition; Step S2, the image quality assessment unit scores the quality of the optical image, and at the same time, the humidity detection unit synchronously detects the humidity on the finger surface; Step S3, if the optical image quality is lower than the preset threshold or the humidity is higher than the preset threshold, the control processing module switches to the ultrasonic acquisition mode. If the optical image quality meets the standard and the humidity is normal, the optical acquisition mode is maintained; Step S4, the verification module extracts and verifies the image data obtained in the two modes; Step S5, when it is detected that the ultrasonic image features are incomplete, the optical fingerprint data of relevant historical fingerprint records are called according to the collected feature points for feature compensation, and secondary verification is performed after compensation.

[0025] It can be understood that, without violating the principle logic, the above-mentioned various embodiments mentioned in the present invention can be combined with each other to form a combined embodiment. Due to space limitations, the present invention will not elaborate further.

[0026] Those skilled in the art can understand that in the above method of the specific implementation manner, the writing order of each step does not mean a strict execution order and does not constitute any limitation to the implementation process. The specific execution order of each step should be determined according to its function and possible internal logic.

[0027] An optical and ultrasonic collaborative fingerprint recognition device and recognition method provided by the present invention can monitor the state of the finger surface in real time through a humidity detection unit and an image quality evaluation unit. When high humidity or insufficient optical image quality is detected, it automatically switches to the ultrasonic mode. Ultrasonic waves can penetrate the water film and stains to obtain the three-dimensional structure information of the fingerprint, effectively solving the problem of the failure of traditional optical sensors in humid and dirty environments; The optical acquisition is fast and low-cost, suitable for daily scenarios. The ultrasonic wave has strong anti-interference ability and is suitable for complex environments. The two work together, covering more usage scenarios and significantly improving the robustness of the system; When the optical recognition result is inaccurate, the verification module uses the three-dimensional image data of the ultrasonic wave to correct the features, reducing misjudgment caused by surface damage or stains. In addition, when the ultrasonic image features are incomplete, it calls historical optical data to compensate for the missing information, forming a dual guarantee mechanism; The subcutaneous biometric features collected by ultrasonic waves are difficult to be counterfeited by two-dimensional forgery means. Combining with the dual verification of the optical surface layer greatly improves the anti-counterfeiting security. The dynamic switching mechanism ensures that the user can complete the recognition with one touch, without repeatedly adjusting the finger position or wiping the surface due to environmental problems, and the operation is more convenient. Thus, through environmental perception, multi-modal data fusion and intelligent decision-making mechanism, the limitations of traditional single-technology fingerprint recognition in complex scenarios are solved.

[0028] The above has described the embodiments of the present invention. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of the technology in the market, or to enable other ordinary skill in the art in the technical field to understand the disclosed embodiments.

Claims

1. An optical and ultrasonic collaborative fingerprint recognition device, characterized in that, Comprising: An optical acquisition module, an ultrasonic acquisition module, an image detection module, a verification module, and a control and processing module; The verification module is respectively connected to the optical acquisition module, the image detection module, and the ultrasonic acquisition module; The image detection module is connected to the control and processing module, and the other end of the control and processing module is connected to the ultrasonic acquisition module; The optical acquisition module is used to obtain an optical image of a fingerprint; The ultrasonic acquisition module is used to obtain a three-dimensional ultrasonic image of a user's fingerprint; The image detection module includes an image quality evaluation unit and a humidity detection unit; The verification module is used to store a preset fingerprint template and perform identification and comparison.

2. The optical and ultrasonic collaborative fingerprint recognition device according to claim 1, wherein The image quality evaluation unit is used to evaluate the quality of the fingerprint optical image obtained by the optical acquisition module. When the evaluation result of the image quality evaluation unit indicates that the quality of the optical image is lower than a preset quality threshold, the control and processing module controls the ultrasonic acquisition module to start fingerprint image acquisition.

3. The optical and ultrasonic collaborative fingerprint recognition device according to claim 1, characterized in that The humidity detection unit is used to detect the humidity of the finger surface. When the detected humidity of the finger surface is higher than a preset humidity threshold, the control and processing module controls the ultrasonic acquisition module to start fingerprint image acquisition.

4. The optical and ultrasonic collaborative fingerprint recognition device according to claim 1, wherein The verification module is used to perform identification and comparison on the fingerprint optical image obtained by the optical acquisition module and the three-dimensional ultrasonic image obtained by the ultrasonic acquisition module with the preset fingerprint template respectively, and output identification result information according to the comparison result.

5. The optical and ultrasonic collaborative fingerprint recognition device according to claim 4, wherein When the optical image identification and comparison result is inaccurate, the verification module uses the three-dimensional ultrasonic image identification and comparison result to correct and compensate the optical image identification and comparison result to improve the accuracy of fingerprint identification.

6. The optical and ultrasonic collaborative fingerprint recognition device according to claim 1, characterized in that The optical acquisition module includes an illumination lamp, an optical lens, and an image sensor. The illumination lamp is used to illuminate the finger fingerprint, the optical lens is used to focus the fingerprint image on the image sensor, and the image sensor is used to convert the optical image into an electrical signal and transmit it to the verification module.

7. The optical and ultrasonic collaborative fingerprint recognition device according to claim 1, characterized in that The ultrasonic acquisition module includes an ultrasonic transmitting probe and an ultrasonic receiving probe. The ultrasonic transmitting probe is used to emit ultrasonic waves to the finger, and the ultrasonic receiving probe is used to receive the reflected ultrasonic wave signal and convert it into three-dimensional ultrasonic image data and transmit it to the verification module.

8. The recognition method of the optical and ultrasonic collaborative fingerprint recognition device according to any one of claims 1-7, characterized in that, Comprising: Step S1, after the device is started, the image detection module is used to detect the finger contact state in real time. When finger contact is detected, the optical acquisition module is triggered to perform initial image acquisition; Step S2, the image quality evaluation unit performs a quality score on the optical image, and at the same time the humidity detection unit synchronously detects the humidity of the finger surface; Step S3, if the quality of the optical image is lower than a preset threshold or the humidity is higher than a preset threshold, the control and processing module switches to the ultrasonic acquisition mode. If the quality of the optical image meets the standard and the humidity is normal, the optical acquisition mode is maintained; Step S4, the verification module performs feature extraction and verification on the image data obtained in the two modes; Step S5, when it is detected that the ultrasonic image features are incomplete, the optical fingerprint data of relevant historical fingerprint records is called according to the collected feature points for feature compensation, and secondary verification is performed after compensation.

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