The application is a divisional application with application number 201510170322.5, the application date of the original application is 2015-04-11, and the invention name is a secure biometric identification and image acquisition system for mobile intelligent equipment.
Disclosure of Invention
The invention provides a safe biological characteristic identification and image acquisition system for mobile intelligent equipment.
An image mirror reflection interference detection and feedback method for mobile terminal biological feature recognition is characterized by comprising the following steps: a) receiving the collected biological characteristic image and outputting an imaging image; b) detecting a position and scale disturbance of specular reflection in the biometric image; c) judging whether the position and scale interference of the specular reflection in the image exceed a preset range, and if so, outputting feedback information; and d) displaying the position and scale information of the specular reflection.
Preferably, the detection method in step b includes one or more of an AdaBoost detection algorithm, a main outline detection algorithm, a LOG edge detection operator, a Canny detection operator, a Moravec corner detection operator, a Harris corner detection operator, and a specular reflection feature distribution statistical function.
Preferably, the determining whether the specular reflection position and the scale in the step c) interfere includes: and judging whether the position of the specular reflection exceeds the area range of the biological features in the preset image, and if so, judging that the specular reflection is interfered.
Preferably, the determining whether the specular reflection position and the scale in the step c) interfere includes: and judging whether the mirror reflection scale exceeds the size range of the biological features in the preset image, and if so, judging that the mirror reflection scale is interfered.
A mobile terminal for image specular reflection interference detection and feedback for mobile terminal biometric identification, characterized by: the method comprises the following steps: the biological characteristic image acquisition equipment is used for acquiring a biological characteristic image; the image mirror reflection interference detection unit is used for detecting the position and scale interference of mirror reflection in an image; the imaging image displacement display unit is used for displaying the position and scale information of the specular reflection; and the feedback prompting unit is used for executing feedback prompting of the position and scale interference of the specular reflection.
Preferably, the detection method of the image specular reflection interference detection unit comprises one or more of an AdaBoost detection algorithm, a main contour detection algorithm, an LOG edge detection operator, a Canny detection operator, a Moravec corner detection operator, a Harris corner detection operator, and a specular reflection feature distribution statistical function.
Preferably, the image specular reflection interference detection unit determining whether the specular reflection position and the scale interfere includes: and judging whether the position of the specular reflection exceeds the area range of the biological features in the preset image, and if so, judging that the specular reflection is interfered.
Preferably, the image specular reflection interference detection unit determines whether the specular reflection scale exceeds a size range of the biological features in the predetermined image, and if so, determines that the specular reflection scale is interfered.
A secure biometric identification system for a mobile smart device includes an application operating system and a secure operating system; the application operating system comprises an application proxy service interface unit for executing application operating system end standardized API procedure call; the security operating system comprises a security application proxy service interface unit for executing the standardized API procedure call of the security operating system end, a security computing unit for executing the data and code computation of the security operating system end, a storage space for providing the data and code of the security operating system end and ensuring the security computing unit to access through an independent security address bus, a memory space for providing the data and code of the security operating system end and ensuring the security computing unit to access through the independent security address bus; the safety computing unit comprises a PKI encryption signature safety algorithm unit and a biological characteristic identification algorithm unit; the biometric feature recognition algorithm unit comprises a registration algorithm unit and a recognition and self-learning algorithm unit.
As an improvement to the secure biometric system for mobile smart devices described in the present invention: the registration process for secure biometric identification is as follows: a. when an external part initiates an application registration request; b. transmitting the registration request to notify a secure application proxy service interface unit through the application proxy service interface unit; c. the standardized API procedure under the safe operating system terminal calls and executes a registration algorithm unit; d. the PKI encryption signature security algorithm unit executes the encryption signature of the registration result, and sends the encryption signature registration result to the application proxy service interface unit through the security application proxy service interface unit; e. and the application proxy service interface unit returns the registration result of the externally received encrypted signature.
The authentication process of the security biological feature identification is ① when an application authentication request is initiated from the outside, ② transmits the authentication request to notify a security application proxy service interface unit through the application proxy service interface unit, ③ a standardized API process call execution identification and self-learning algorithm unit under the security operating system terminal, ④ a PKI encryption signature security algorithm unit executes an authentication result encryption signature and sends the encryption signature authentication result to notify the application proxy service interface unit through the security application proxy service interface unit, and ⑤ an application proxy service interface unit returns an authentication result of an externally received encryption signature.
As a further improvement of the secure biometric system for mobile smart devices of the present invention: the registration algorithm unit is used for executing the following control steps:
s200, initializing a defined cycle COUNT COUNT (0), a template COUNT N (0), a template number TN and a cycle number TC; wherein: the COUNT is defined as the cycle COUNT in the algorithm registration flow, and the N is defined as the template COUNT in the algorithm registration flow; TN is defined as the number of preset templates in the algorithm registration process, and the preferable TN > is 3; defining TC as a preset cycle number in the algorithm registration process, and preferably, the TC > is 3; s201, collecting a real-time biological characteristic image which accords with a self-adaptive quality standard; s202, extracting image biological characteristic information to generate a characteristic template, wherein the self-increment accumulated number N of the template is N + 1; s203, judging that the template count N is larger than or equal to TN, if so, executing S204, and if not, returning to execute S201; s204, the cycle COUNT self-increment cumulative COUNT is equal to COUNT + 1; s205, judging whether a combined comparison result set C (TN, 2) formed among the TN number of templates completely meets a preset registration threshold standard, if so, executing S208, and if not, executing S206; wherein: the combined comparison result set C (TN, 2) ═ TN! (2 | (TN-2) |) S206, determining that the loop COUNT > TC, if so, execute S207, if not, reset the template COUNT N to 0 and return to execute S201; s207, registration failure; and S208, successfully registering, selecting the globally optimal template in the template combination comparison result as a registered template, encrypting and storing the registered template in a secure storage unit through PKI.
As an improvement to the secure biometric system for mobile smart devices described in the present invention: the identification and self-learning algorithm unit is used for executing the following control steps: s301, collecting a real-time biological characteristic image which meets the self-adaptive quality standard; s302, extracting image biological characteristic information to generate a current characteristic template; s303, judging whether the comparison result of the current template and the registration template or the self-learning template meets a preset identification threshold standard, if so, executing S304, and if not, executing S306; s304, judging whether the template comparison result meets a preset self-learning threshold standard, if so, executing S305, and if not, executing S307; s305, judging whether the image biological characteristic quality meets a preset self-learning quality standard, if so, executing S308, and if not, executing S307; s306, the identification and the template self-learning fail; s307, successfully recognizing, and failing to learn the template by self; and S308, successfully identifying, encrypting and storing the current template as a self-learning template in a safety storage unit by PKI.
The safety biological characteristic recognition system for the mobile intelligent device is characterized in that the real-time biological characteristic image which meets the self-adaptive quality standard is collected, the method comprises the following steps of S400, initialization definition, high-grade quality standard Qh, low-grade quality standard Ql, self-adaptive quality standard Q which is Qh, quality standard fine adjustment step size △ Q, S401, real-time biological characteristic image collection, S402, judging whether the self-adaptive quality standard Q is larger than or equal to Ql, executing S403, if not, Q which is Ql, returning to execute S401, S403, judging whether the current image biological characteristic quality meets the self-adaptive quality standard Q, executing S404, if not, Q which is Q- △ Q, returning to execute S401, and S404, returning to the real-time biological characteristic image which meets the self-adaptive quality standard.
A biological characteristic image acquisition system for mobile intelligent equipment comprises biological characteristic image acquisition equipment for acquiring a biological characteristic image, a biological characteristic image acquisition equipment safety drive control unit for executing real-time feedback drive control of the biological characteristic image acquisition equipment to output an imaging image, and a display screen safety drive control unit for executing real-time imaging image displacement display, detection of imaging image biological characteristic deviation and mirror reflection interference and feedback prompt.
As an improvement to the biometric image acquisition system of the present invention: the biological characteristic image acquisition equipment comprises a distance sensor for measuring object distance information, a near infrared LED light source for radiating imaging near infrared light, a current driver for driving the near infrared LED light source to adjust radiation intensity, a front optical filter and/or a rear optical filter for filtering visible light to penetrate through the near infrared light for imaging, an optical imaging lens for physically focusing the near infrared light, an automatic focusing driver for driving the optical imaging lens to automatically focus, an image imaging sensor for photoelectrically converting and outputting an imaging image, and a display screen for displaying a displacement imaging image, biological characteristic deviation of the imaging image and feedback prompt information of mirror reflection interference.
As a further improvement to the biometric image acquisition system of the present invention: the safety driving control unit of the biological characteristic image acquisition equipment comprises an object distance information measuring unit, a radiation intensity adjusting unit, an automatic focusing unit and an imaging mode control unit.
As a further improvement to the biometric image acquisition system of the present invention: the display screen safety driving control unit comprises an imaging image displacement display unit, an image biological characteristic deviation detection unit, an image mirror reflection interference detection unit and a feedback prompt unit.
As a further improvement to the biometric image acquisition system of the present invention: the safety drive control unit of the biological characteristic image acquisition equipment is used for executing real-time feedback drive control of the biological characteristic image acquisition equipment to output an imaging image and comprises the following feedback control steps: s101, an object distance information measuring unit dynamically measures object distance information D of a distance sensor in real time; s102, judging whether the object distance information D is in a working range, if so, executing S103, and if not, feeding back a prompt to adjust the distance and returning to execute S101; s103, the radiation intensity adjusting unit dynamically feeds back and controls the current driver to drive the near-infrared LED light source radiation intensity I to change in real time according to the object distance information D; s104, the automatic focusing unit dynamically feeds back and controls an automatic focusing driver to drive the optical imaging lens to automatically focus in real time according to the object distance information D; and S105, the imaging mode control unit dynamically controls the frame radiation intensity I, the frame time T and the frame frequency F of the synchronous time sequence pulse imaging mode in real time to output an imaging image.
As a further improvement to the biometric image acquisition system of the present invention: the automatic focusing unit further finely adjusts a local area of a focusing position corresponding to the current object distance information D, namely, the focusing position corresponding to the current object distance information D is taken as a center, and the local area is defined as a range to carry out scanning with fine step length so as to obtain the focusing effect of the optimal image space focus position; the imaging mode control unit dynamically controls the frame time and frame frequency output imaging image method of the synchronous time sequence pulse imaging mode in real time, and is specifically realized by controlling the frame time T and frame frequency F output of the pulse imaging mode of the image imaging sensor exposure and the near-infrared LED light source radiation through the synchronous time sequence; the pulse imaging mode adopts pulse amplitude modulation to realize frame radiation intensity I control output; the pulse imaging mode adopts pulse width duty ratio modulation to realize frame time T control output; and the pulse imaging mode adopts pulse unit period frequency modulation to realize frame frequency F control output.
As a further improvement to the biometric image acquisition system of the present invention: the display screen safety drive control unit is used for executing displacement display of a real-time imaging image, detection and feedback prompt of biological characteristic deviation and mirror reflection interference of the imaging image, and comprises the following control steps: s106, dynamically displaying the displacement processed imaging image in real time by an imaging image displacement display unit; s107, an image biological characteristic deviation detection unit dynamically detects the position and scale deviation of the biological characteristic in the image in real time; s108, judging whether the position and the scale of the biological feature in the image deviate or not, if so, executing the feedback prompt of the position and the scale deviation by the feedback prompt unit, returning to execute S106, and if not, executing S109; s109, an image mirror reflection interference detection unit dynamically detects the position and scale interference of mirror reflection in an image in real time; and S110, judging whether the image specular reflection position and the scale are interfered, if so, executing the specular reflection position and scale interference feedback prompt by the feedback prompt unit and returning to execute S106, and if not, returning to execute S106.
As a further improvement to the biometric image acquisition system of the present invention: the displacement processing of the imaged image comprises: adjusting the X _ SHIFT and Y _ SHIFT of the center of an imaging image displayed by a display screen through X-Y coordinate axis displacement; the specific calculation of the adjustment X-Y axis displacement (X _ SHIFT, Y _ SHIFT) is as follows:
X_SHIFT=β*(Xscreen–Ximager)/PS
Y_SHIFT=β*(Yscreen–Yimager)/PS
β=EFL/(D-EFL)
the system comprises a display screen, a biological characteristic image acquisition device, an EFL (X _ SHIFT and Y _ SHIFT) and a PS (PS) and a unit pixel physical scale of an image imaging sensor, wherein the X _ SHIFT and the Y _ SHIFT are imaging image center X and Y coordinate displacement, unit pixels, Xscreen and Yscreen which are displayed by the display screen respectively, the X and Y coordinate physical positions, unit centimeters and cm, the Xiimager and the Yimager are imaging image center X and Y coordinate physical positions, unit centimeters and cm, the β is optical magnification and unitless, the EFL is an equivalent focal length of an.
As a further improvement to the biometric image acquisition system of the present invention: the feedback prompting unit executes a display screen to display and dynamically adjusts the biological characteristic position and the scale deviation information in real time; and the feedback prompting unit executes a display screen to display real-time dynamic adjustment mirror reflection position and scale interference information.
A combined optimization control method for realizing safety limitation of the total radiation amount of a biological characteristic individual in a unit period and acquiring a high-quality interference-free biological characteristic imaging image of a biological characteristic image acquisition system comprises the following steps: (1) completely turning off the radiation of the near-infrared LED light source when the object distance information D exceeds the close distance limit; (2) defining the irradiation energy J0 of the individual biometric feature in each frame period of the biometric image acquisition system; j0 ═ E × T; defining the radiation energy JE of the biological characteristic individual in a unit period of a biological characteristic image acquisition system; JE ═ J0 × F < Jlimit; (3) according to the definition relation of JE in (2), through jointly optimizing control parameters: the irradiation energy of the biological characteristic individual in each frame period is J0, and the number of frames in a unit period is F, so that the irradiation energy of the biological characteristic individual in the unit period is limited to JE < Jlimit; (4) according to the definition relation of J0 in the step (2), jointly optimizing control parameters E and T inverse proportion relation, namely E is J0/T, T is J0/E, improving the irradiation illumination E of each frame period of the individual biological characteristics, and reducing the irradiation and exposure time T of each frame period of the individual biological characteristics, namely adopting the high irradiation illumination E of each frame period, wherein the short irradiation and exposure time T of each frame period are used for obtaining high-quality interference-free biological characteristic imaging images; wherein: jlimit is the safe limit energy of the individual with the biological characteristics irradiated in a unit period; t is the irradiation time of each frame period of the individual biological characteristics, namely the frame time of the synchronous time sequence pulse imaging mode of the exposure of the image imaging sensor and the radiation of the near-infrared LED light source; f is the frame number in a unit period, namely the frame frequency of the synchronous time sequence pulse imaging mode of the exposure of the image imaging sensor and the radiation of the near-infrared LED light source; e is the illumination intensity of each frame period of the individual with biological characteristics; and D is object distance information.
Summarizing the above description, the following advantages are achieved by the present invention:
1. and a complete security registration authentication flow system is realized, and external security attack is prevented.
2. The optimal stability and consistency of the biological characteristic template in the registration authentication process system are realized, the success rate during registration and identification is improved, and the registration and identification speed is improved; .
3. The success rate of registration and identification is further improved under the conditions that different acquisition environments and biological characteristics change per se in a registration authentication flow system, and the like, and the registration and identification speed is improved;
4. the image biological characteristic quality standard self-adaption in a registration authentication flow system is realized, the success rate of registration and identification is improved, and the registration and identification speed is improved;
5. the biological characteristic imaging image with constant brightness is obtained in an image acquisition flow system.
6. The method can realize the rapid acquisition of the biological characteristic imaging image with clear and stable focus in 100ms in an image acquisition flow system.
7. And realizing that the biological characteristic position and the scale deviation of the image acquired in the image acquisition flow system are in a preset range.
8. The mirror reflection position and the scale interference of the image acquired in the image acquisition flow system are out of the preset range.
9. The biological characteristic image collected in the image collection flow system is kept in an axial direct-viewing state.
10. The method realizes the safety limit of the total radiation quantity of the biological characteristic individuals in a unit period, and obtains a high-quality interference-free biological characteristic imaging image.
The embodiment 1 and the invention provide a safe biological characteristic identification and image acquisition system for a mobile intelligent device and a related method based on the system.
The security biometric identification and image acquisition system for the mobile intelligent device comprises a security biometric identification system for the mobile intelligent device and a biometric image acquisition system for the mobile intelligent device.
As shown in fig. 1, the system for secure biometric identification for a mobile smart device in this embodiment includes an application operating system and a secure operating system; the application operating system comprises an application agent service interface unit; the safety operation system comprises a safety agent service interface unit, a safety calculation unit, a safety storage unit and a safety memory unit; the application proxy service interface unit is used for executing API procedure call standardized by an application operating system end; the secure application proxy service interface unit is used for executing API procedure call standardized by a secure operating system end; the safety computing unit is used for executing the computation of the data and the code of the safety operating system end; the safety storage unit is used for providing a storage space of data and codes of a safety operating system end and ensuring that the safety computing unit accesses through an independent safety address bus; the safety memory unit is used for providing a memory space of data and codes of the safety operating system end and ensuring that the safety computing unit accesses through the independent safety address bus. The safety computing unit comprises a PKI encryption signature safety algorithm unit and a biological characteristic identification algorithm unit; the biometric feature recognition algorithm unit comprises a registration algorithm unit and a recognition and self-learning algorithm unit.
The preferred registration process for the secure biometric identification of the mobile intelligent device in embodiment 1 of the present invention includes the following steps:
a. when an external part initiates an application registration request;
b. transmitting the registration request to notify a secure application proxy service interface unit through the application proxy service interface unit; specifically, the registration request notifies the security application proxy service interface unit to execute the standardized API procedure call at the security operating system end through the application proxy service interface unit executing the standardized API procedure call at the application operating system end;
c. the standardized API procedure under the safe operating system terminal calls and executes a registration algorithm unit;
d. the PKI encryption signature security algorithm unit executes the encryption signature of the registration result, and sends the encryption signature registration result to the application proxy service interface unit through the security application proxy service interface unit;
e. and the application proxy service interface unit returns the registration result of the externally received encrypted signature.
The authentication process for the secure biometric identification of the mobile intelligent device, which is preferred in embodiment 1 of the present invention, includes the following steps:
① when an external application authentication request is initiated;
②, the authentication request is transmitted to the security application proxy service interface unit through the application proxy service interface unit, concretely, the authentication request executes the API procedure call standardized under the application operating system end through the application proxy service interface unit to inform the security application proxy service interface unit to execute the API procedure call standardized under the security operating system end;
③ executing recognition and self-learning algorithm unit by the standardized API procedure call under the safe operating system terminal;
④ PKI encryption signature security algorithm unit executes the authentication result encryption signature, and sends the encryption signature authentication result to inform the application proxy service interface unit through the security application proxy service interface unit;
⑤ the application proxy service interface unit returns the externally received cryptographic signature authentication result.
In fig. 1, a preferred application operating system in embodiment 1 of the present invention is an android OS, and a secure operating system is a TrustZone OS in which a TEE (trusted execution environment) is deployed. The embodiment 1 of the invention is used for a safe biological characteristic identification system of mobile intelligent equipment, can realize a complete safe registration authentication process system of biological characteristic identification, and ensures that the mobile intelligent equipment is not attacked by external safety.
As shown in fig. 3, the registration algorithm unit according to the present invention is configured to execute the following control steps, including:
s200, initializing a defined cycle COUNT COUNT (0), a template COUNT N (0), a template number TN and a cycle number TC;
wherein:
COUNT is defined as the loop COUNT in the algorithm registration flow,
n is defined as the template count in the algorithm registration process;
TN is defined as the number of preset templates in the algorithm registration process, and the preferable TN > is 3;
defining TC as a preset cycle number in the algorithm registration process, and preferably, the TC > is 3;
s201, collecting a real-time biological characteristic image which accords with a self-adaptive quality standard;
s202, extracting image biological characteristic information to generate a characteristic template, wherein the self-increment accumulated number N of the template is N + 1;
s203, judging that the template count N is larger than or equal to TN, if so, executing S204, and if not, returning to execute S201;
s204, the cycle COUNT self-increment cumulative COUNT is equal to COUNT + 1;
s205, judging whether a combined comparison result set C (TN, 2) formed among the TN number of templates completely meets a preset registration threshold standard, if so, executing S208, and if not, executing S206;
wherein: the combined comparison result set C (TN, 2) ═ TN! Example 1 illustrates TN ═ 4, i.e. templates {1,2, 3,4}, and the set of combinatorial alignments formed between templates is C (4,2) ═ 4! (2! (4-2)!) 6, the set of combinatorial alignments is specified as follows { R (1,2), R (1, 3), R (1,4), R (2,3), R (2,4), R (3,4) }.
In the embodiment 1 of the invention, the purpose that the combination comparison result set among the templates completely meets the preset registration threshold standard is to ensure the stability and consistency of the image biological characteristics among the templates and improve the success rate of template identification;
s206, judging that the loop COUNT is greater than TC, if so, executing S207, and if not, resetting the template COUNT N to be 0 and returning to execute S201;
s207, registration failure
And S208, successfully registering, selecting the globally optimal template in the template combination comparison result as a registered template, encrypting and storing the registered template in a secure storage unit through PKI.
In embodiment 1 of the present invention, preferably, a globally optimal template in the template combination comparison results is selected as a registration template, for example, TN ═ 4, that is, a template {1,2, 3,4}, the comparison result is set as a normalized numerical value [0, 1], 0 represents a complete inconsistency, 1 represents a complete consistency, and the globally optimal template is a template corresponding to the largest global accumulated value of the comparison results between other templates, max { S1, S2, S3, S4 };
S1=R(1,2)+R(1,3)+R(1,4);
S2=R(1,2)+R(2,3)+R(2,4);
S3=R(1,3)+R(2,3)+R(3,4);
S4=R(1,4)+R(2,4)+R(3,4);
wherein:
s1 is the global accumulated value of the comparison result between the template 1 and other templates, S1 is the maximum, and the template 1 is the globally optimal template;
s2 is the global accumulated value of the comparison result between the template 2 and other templates, S2 is the maximum, and the template 2 is the globally optimal template;
s3 is the global accumulated value of the comparison result between the template 3 and other templates, S3 is the maximum, and the template 3 is the globally optimal template;
s4 is the global accumulated value of the comparison result between the template 4 and other templates, S4 is the maximum, and the template 4 is the globally optimal template.
In the embodiment 1 of the invention, the template with the optimal global situation in the template combination comparison result is used as the registration template, and the aim is to select the template with the optimal stability and consistency of the image biological characteristics in the combination comparison result set, improve the success rate during registration and identification and improve the registration and identification speed at the same time.
As shown in fig. 4, the recognition and self-learning algorithm unit according to the present invention performs the following control steps including:
s301, collecting a real-time biological characteristic image which meets the self-adaptive quality standard;
s302, extracting image biological characteristic information to generate a current characteristic template;
s303, judging whether the comparison result of the current template and the registration template or the self-learning template meets a preset identification threshold standard, if so, executing S304, and if not, executing S306;
s304, judging whether the template comparison result meets a preset self-learning threshold standard, if so, executing S305, and if not, executing S307;
s305, judging whether the image biological characteristic quality meets a preset self-learning quality standard, if so, executing S308, and if not, executing S307;
s306, the identification and the template self-learning fail;
s307, successfully recognizing, and failing to learn the template by self;
s308, successfully identifying and storing the current template as a self-learning template in a safe storage unit through PKI encryption;
the embodiment 1 of the invention adopts the preset registration threshold standard, the identification threshold standard and the self-learning threshold standard, and aims to further improve the success rate during registration and identification and improve the registration and identification speed; the embodiment 1 of the invention adopts a template self-learning method to further improve the success rate of registration and identification under the conditions that different acquisition environments and biological characteristics (physiological) change and the like, and simultaneously improve the registration and identification speed; the embodiment 1 of the invention adopts the self-learning threshold standard and the self-learning quality standard of the set template comparison result, and aims to further improve the quality of the self-learning template, improve the success rate during registration and identification and simultaneously improve the registration and identification speed; when the method is applied to large-scale people, the biological characteristic quality (the biological characteristic quality formed physiologically) of the image of the biological characteristic individual is changed from high-grade quality to low-grade quality, the change span range is extremely large, if the biological characteristic quality of part of the biological characteristic individuals can not meet the requirement when the biological characteristic quality is judged by a single high-grade quality standard, the success rate of registration and identification is influenced, and the registration and identification speed is influenced; if the biological characteristic quality of partial biological characteristic individuals is reduced when the single low-level quality standard is used for judgment, the success rate of registration and identification is influenced, and the registration and identification speed is influenced.
As shown in fig. 5, the embodiment 1 of the present invention adopts an image biometric quality standard adaptive method, which includes the following steps of S400, initializing definition of a high-level quality standard Qh, a low-level quality standard Ql, an adaptive quality standard Q ═ Qh, and a quality standard fine adjustment step size △ Q;
s401, collecting a real-time biological characteristic image;
s402, judging that the adaptive quality standard Q is not less than Ql, if so, executing S403, and if not, returning to execute S401;
s403, judging whether the biological characteristic quality of the current image meets the self-adaptive quality standard Q, if so, executing S404, and if not, returning to execute S401;
and S404, returning the real-time biological characteristic image which meets the self-adaptive quality standard.
In the embodiment 1 of the invention, the image biological characteristic quality standard self-adapting method is adopted, the biological characteristic quality of all biological characteristic individuals meets the self-adapting quality standard requirement of dynamic change from a high-grade quality standard to a low-grade quality standard, the registration and identification success rate is further improved, and the registration and identification speed is improved.
As shown in fig. 2, an embodiment 1 of the present invention provides a biometric image capturing system for a mobile smart device, including a biometric image capturing device, a biometric image capturing device security driving control unit, and a display screen security driving control unit. The biometric image acquisition device in embodiment 1 of the present invention is used to acquire real-time biometric images and provide high-quality images required by a secure biometric identification system. The biological characteristic image acquisition equipment provided by the embodiment 1 of the invention is used for acquiring a biological characteristic image and comprises a distance sensor, a near infrared LED light source, a current driver, a front optical filter and/or a rear optical filter, an optical imaging lens, an automatic focusing driver, an image imaging sensor and a display screen; wherein: the distance sensor is used for measuring object distance information; the near-infrared LED light source is used for radiating imaging near-infrared light; the current driver is used for driving the near-infrared LED light source to adjust the radiation intensity; the front optical filter and/or the rear optical filter are used for filtering visible light to transmit near infrared light for imaging; the optical imaging lens is used for physically focusing near infrared light; the automatic focusing driver is used for driving the optical imaging lens to automatically focus; the image imaging sensor is used for photoelectrically converting and outputting an imaging image; the display screen is used for displaying the displacement imaging image and displaying feedback prompt information of biological characteristic deviation and mirror reflection interference of the imaging image. The safety driving control unit of the biological characteristic image acquisition equipment is used for executing real-time feedback driving control of the biological characteristic image acquisition equipment to output an imaging image; the display screen safety driving control unit is used for executing displacement display of a real-time imaging image, detection and feedback prompt of biological characteristic deviation and mirror reflection interference of the imaging image.
As shown in fig. 6, the safety driving control unit of the biometric image capturing device according to embodiment 1 of the present invention includes an object distance information measuring unit, a radiation intensity adjusting unit, an auto-focusing unit, and an imaging mode control unit; the display screen safety driving control unit comprises an imaging image displacement display unit, an image biological characteristic deviation detection unit, an image mirror reflection interference detection unit and a feedback prompt unit.
As shown in fig. 7, the biometric image capturing device security driving control unit according to the present invention for performing real-time feedback driving control of the biometric image capturing device to output an imaging image includes the following feedback control steps:
s101, an object distance information measuring unit dynamically measures object distance information D (unit cm, centimeter) of the distance sensor in real time;
s102, judging whether the object distance information D is in a working range, if so, executing S103, and if not, feeding back a prompt to adjust the distance and returning to execute S101;
s103, the radiation intensity adjusting unit dynamically feeds back and controls the current driver to drive the radiation intensity I of the near-infrared LED light source to change in real time according to the object distance information D;
preferably, in embodiment 1 of the present invention, the radiation intensity of the near-infrared LED light source (unit mW/sr, milliwatt per sphere degree) has I ═ E × D <2>, E is the illuminance of the biological characteristic individual under irradiation (unit mW/cm <2>, milliwatt per square centimeter), the radiation intensity adjusting unit dynamically adjusts the radiation intensity of the near-infrared LED light source in real time to maintain the E constant range, is not affected by the imaging distance of the biological distance, maintains the brightness of the imaging image in the constant range, and safely limits the total amount of the biological characteristic individual under irradiation at a short distance. If the object distance information D exceeds the limit of 10cm in a close distance, the radiation of the near-infrared LED light source is completely turned off;
the method can obtain the biological characteristic imaging image with constant brightness, and simultaneously avoid the biological characteristic individuals from being excessively radiated in a short distance;
the invention effectively avoids the problems of non-real-time and unstable control process caused by the change of image content by adopting an image brightness evaluation analysis method;
s104, the automatic focusing unit dynamically feeds back and controls an automatic focusing driver to drive the optical imaging lens to automatically focus in real time according to the object distance information D;
preferably, in embodiment 1 of the present invention, the auto-focusing driver includes a VCM motor, a closed-loop motor, a center motor, a liquid crystal driver, an MEMS driver, and the like;
in embodiment 1 of the present invention, preferably, the auto-focus driver parameter P ═ L (D), where L is a function of a relationship between the object distance information D and the corresponding physical focus position formed by the optical imaging lens, and the auto-focus driver parameter P corresponds to the image focal position;
if the auto-focus driver adopts a VCM motor, a closed-loop motor, a center motor, etc., the auto-focus driver parameter P is an image distance, P ═ l (D) ═ EFL ═ D/(D-EFL), where EFL is an equivalent focal length of the optical imaging lens, and the image distance P corresponds to an image focal point position;
if the automatic focusing driver adopts a liquid crystal driver and a MEMS driver, the automatic focusing driver parameter P is optical diopter, and P is L (D) is 1/D, and the optical diopter P corresponds to the focal position of the image space;
furthermore, the automatic focusing driver is PDAF, namely phase detection automatic focusing, and the automatic focusing of the optical imaging lens is controlled through closed-loop phase detection feedback;
preferably, in consideration of the stability and accuracy of the actual optical system under different imaging conditions, the present invention further fine-tunes the local area of the focusing position corresponding to the current object distance information D, i.e. defines the local area as a range to perform fine step scanning so as to obtain the focusing effect of the optimal image space focal position, with the focusing position corresponding to the current object distance information D as the center;
the automatic focusing method adopted by the invention can quickly acquire the biological characteristic imaging image with clear and stable focusing within 100 ms;
s105, the imaging mode control unit dynamically controls the frame radiation intensity I, the frame time T and the frame frequency F of the synchronous time sequence pulse imaging mode in real time to output an imaging image;
in embodiment 1 of the present invention, preferably, the method for outputting an imaging image by an imaging mode control unit dynamically controlling frame time T (unit, millisecond per frame) and frame frequency F (unit, frame per unit period) of a synchronous timing pulse imaging mode in real time is specifically implemented by controlling frame time T and frame frequency F output of an image imaging sensor exposure (integration) and a pulse imaging mode of near-infrared LED light source radiation through a synchronous timing; that is, the frame time T and the frame frequency F of the image imaging sensor exposure (integration) and the frame time T and the frame frequency F of the near-infrared LED light source radiation keep the same timing of the pulse imaging mode;
further, in embodiment 1 of the present invention, preferably, the pulse imaging mode uses pulse amplitude modulation to realize frame radiation intensity I control output.
Further, in embodiment 1 of the present invention, preferably, the pulse imaging mode uses pulse width duty cycle modulation to realize frame time T control output.
Further, in embodiment 1 of the present invention, preferably, the pulse imaging mode uses pulse unit period frequency modulation to realize frame frequency F control output.
In the embodiment 1 of the invention, the biological characteristic image acquisition equipment safety drive control unit finally outputs an imaging image through the feedback control steps S101-S105 and is further used for a display screen safety drive control unit;
as shown in fig. 8, the display screen safety driving control unit of the present invention is used for performing displacement display of a real-time imaging image, detection and feedback prompt of biological characteristic shift and mirror reflection interference of the imaging image, and includes the following control steps:
s106, dynamically displaying the displacement processed imaging image in real time by an imaging image displacement display unit;
due to the limitation of a physical installation structure, the physical center of an imaging image displayed by a display screen and the physical optical center of the biological characteristic image acquisition equipment cannot realize the same optical axis (coaxial state);
in the embodiment 1 of the invention, for example, in the application of a mobile phone, a biological characteristic image acquisition device at the front camera position of the mobile phone cannot be installed behind an actual display screen, and the optical center physical position of the biological characteristic image acquisition device and the physical center position of an imaging image displayed by the actual mobile phone display screen certainly cannot realize the same optical axis; under the condition that the same optical axis cannot be realized, when a user observes an imaging image of a display screen of the mobile phone, a biological characteristic image acquired by biological characteristic image acquisition equipment arranged at the front camera position of the mobile phone can cause the formation of an off-axis oblique view state rather than an on-axis direct view state; the biological characteristic tissue is directly caused to be in a three-dimensional off-axis state under the off-axis squint state, so that the biological characteristic tissue deforms, non-geometric distortion is generated on the biological characteristic image, and the registration and identification success rate and the registration and identification speed are greatly reduced; in the embodiment 1 of the invention, the displacement between the physical center of the imaging image displayed on the display screen and the physical optical center of the biological characteristic image acquisition equipment is dynamically adjusted in real time, so that the acquired biological characteristic image is kept in an axial direct-viewing state; the invention is further particularly explained in the following: in the axial direct-view state, compared with the coaxial direct-view state, the difference is only that the displacement of the optical axis center (X-Y coordinate axis) occurs, the actual imaging image effect is reflected that the displacement of the image center (X-Y coordinate axis) occurs, and the off-axis oblique-view deformation of the biological characteristic tissue is not generated;
furthermore, in embodiment 1 of the present invention, the imaging image displacement display unit dynamically displays the imaging image subjected to the displacement processing in real time, and the specific method for the displacement processing of the imaging image includes:
adjusting the X _ SHIFT and Y _ SHIFT of the center of an imaging image displayed by a display screen through X-Y coordinate axis displacement;
the specific calculation of the adjusted X-Y axis displacement (X _ SHIFT, Y _ SHIFT) is as follows:
X_SHIFT=β*(Xscreen–Ximager)/PS
Y_SHIFT=β*(Yscreen–Yimager)/PS
β=EFL/(D-EFL)
wherein:
(X _ SHIFT, Y _ SHIFT) are respectively the center X of an imaging image displayed by the display screen, the displacement of a Y coordinate axis, a unit pixel and pixels;
(Xscreen, Yscreen) is the physical position of X, Y coordinate axes of the center of an imaging image displayed by a display screen, and the unit is centimeter and cm;
(Ximager, Yimager) are the physical positions of the optical center X and Y coordinate axes of the biological characteristic image acquisition equipment, and the units are centimeter and cm;
β is the optical magnification of the biological characteristic image acquisition equipment, and has no unit;
EFL is equivalent focal length of the optical imaging lens, unit millimeter, mm;
d is object distance, unit centimeter, cm; (ii) a
PS is the unit pixel physical dimension of the image imaging sensor, in microns per pixel, um/pixel.
In embodiment 1 of the present invention, taking practical mobile phone applications as examples, specific parameters are as follows:
EFL=3mm,D=20cm,PS=1.12um/pixel,
(Xscreen–Ximager)=1cm;
(Yscreen–Yimager)=3cm;
β=0.0152;(X_SHIFT,Y_SHIFT)=(136pixels,408pixels);
namely, the center of the image displayed on the display screen is adjusted to 136 pixels and 408 pixels through X-Y axis displacement.
In the embodiment 1 of the invention, the acquired biological characteristic image is kept in an axial direct-viewing state by dynamically displaying the displacement processed imaging image in real time.
S107, an image biological characteristic deviation detection unit dynamically detects the position and scale deviation of the biological characteristic in the image in real time; preferably, in embodiment 1 of the present invention, the image biometric characteristic deviation detecting unit calculates the effective position and the effective scale information of the biometric characteristic in the image according to the real-time imaging image, that is, the XY-axis direction positional deviation and the Z-axis scale deviation, which represent the left-right-up-down direction positional deviation and the distance scale deviation;
preferably, in embodiment 1 of the present invention, the biological characteristic shift detection method includes an AdaBoost detection algorithm, a profile-active detection algorithm, an LOG edge detection operator, a Canny detection operator, a Moravec corner detection operator, a Harris corner detection operator, and the like;
furthermore, in embodiment 1 of the present invention, preferably, the biometric characteristic deviation detection method further includes using a biometric characteristic distribution statistical function;
s108, judging whether the position and the scale of the biological feature in the image deviate or not, if so, executing the feedback prompt of the position and the scale deviation by the feedback prompt unit, returning to execute S106, and if not, executing S109;
in a preferred form of embodiment 1 of the present invention,
judging whether the position of the biological features in the image deviates and exceeds the range of a preset image boundary area;
judging whether the biological characteristics in the image have scale deviation and exceed a preset image scale size range;
preferably, in embodiment 1 of the present invention, the feedback prompting unit executes the display screen to display the real-time dynamic adjustment biological characteristic position and the scale deviation information;
s109, an image mirror reflection interference detection unit dynamically detects the position and scale interference of mirror reflection in an image in real time; preferably, in embodiment 1 of the present invention, the image specular reflection interference detection unit calculates effective position interference and effective scale interference information of specular reflection in the image according to the real-time imaging image;
preferably, in embodiment 1 of the present invention, the image specular reflection interference detection method includes an AdaBoost detection algorithm, a main contour detection algorithm, an LOG edge detection operator, a Canny detection operator, a Moravec corner detection operator, a Harris corner detection operator, and the like;
furthermore, in the embodiment 1 of the present invention, preferably, the image specular reflection interference detection method further includes using a specular reflection characteristic distribution statistical function;
s110, judging whether the image mirror reflection position and scale are interfered, if so, executing mirror reflection position and scale interference feedback prompt by a feedback prompt unit and returning to execute S106, and if not, returning to execute S106;
in a preferred form of embodiment 1 of the present invention,
judging whether the mirror reflection in the image is interfered by the position and exceeds the range of a preset biological characteristic area in the image;
judging whether the mirror reflection in the image is in scale interference or not, wherein the scale interference exceeds the size range of the biological features in the preset image;
preferably, in embodiment 1 of the present invention, the feedback prompting unit executes the display screen to display the real-time dynamic adjustment mirror reflection position and the scale interference information;
the display screen safety driving control unit controls the display screen to display the imaging image subjected to real-time displacement processing in a feedback control mode according to the real-time imaging image output by the image imaging sensor, and detects information such as biological characteristic position and scale deviation and mirror reflection position and scale interference in the image for feedback prompt adjustment;
realizing dynamic adjustment of image biological characteristic position deviation and scale deviation, ensuring that the biological characteristic position is in a preset image boundary area range, and ensuring that the biological characteristic scale is in a preset image scale size range;
the dynamic adjustment of the image mirror reflection position interference and the scale interference is realized, the mirror reflection position is ensured to be out of the range of the biological characteristic area in the preset image, and the mirror reflection scale is ensured to be out of the range of the biological characteristic size in the preset image.
The embodiment 1 of the invention adopts a combined optimization control method for realizing safety limitation of the total radiation amount of a biological characteristic individual in a unit period of a biological characteristic image acquisition system and acquiring a high-quality interference-free biological characteristic imaging image, which comprises the following steps:
1. completely turning off the radiation of the near-infrared LED light source when the object distance information D exceeds the close distance limit;
2. defining the irradiation energy J0 of the individual biological feature in each frame period of the biological feature image acquisition system, (unit, Joule per square centimeter per frame period, J/cm <2>/frame),
J0=E*T;
defining the irradiation energy JE of the biological characteristic individual in a unit period of the biological characteristic image acquisition system, (unit, Joule per square centimeter, J/cm <2>),
JE=J0*F<Jlimit;
3. and (3) according to the definition relation of JE in 2, by jointly optimizing control parameters: the irradiation energy of the biological characteristic individual in each frame period is J0, and the number of frames in a unit period is F, so that the irradiation energy of the biological characteristic individual in the unit period is limited to JE < Jlimit;
further, embodiment 1 of the present invention specifically states that the irradiation energy J0 of the biometric individual in each frame period is determined by the number F of frames in the predetermined unit period according to the definition relationship of JE in fig. 2.
4. According to the definition relation of J0 in 2, jointly optimizing control parameters E and T inverse proportion relation, namely E is J0/T, T is J0/E, the irradiation illumination E of each frame period of the individual biometric features is improved, the irradiation and exposure time T of each frame period of the individual biometric features is reduced, namely the high irradiation illumination E of each frame period is adopted, and the short irradiation and exposure time T of each frame period is used for obtaining high-quality interference-free biometric imaging images.
Further, embodiment 1 of the present invention specifically shows that the maximum advantage of the parameter joint optimization control using the inverse proportion relationship is that the requirement of high radiation illuminance of each frame period can be met, the requirement of short radiation and exposure time of each frame period can also be met, and the product of the parameters E and T meets the preset limited radiation energy J0 of the biometric individual in each frame period.
The high radiation illumination of each frame period is used for effectively filtering imaging interference such as background light, and the short radiation and exposure time of each frame period are used for solving the imaging interference such as motion defocusing.
Further, embodiment 1 of the present invention specifically shows that the high-irradiance imaging with each frame period in the synchronous time-series pulse imaging mode can solve the imaging interference such as effectively filtering the background light by improving the signal-to-noise ratio of the imaging and the background light.
Further, embodiment 1 of the present invention specifically illustrates that the use of short-time irradiation and exposure imaging per frame period in a synchronized time-sequential pulse imaging mode can resolve all X-Y-Z axis motion defocusing.
Wherein:
jlimit is the safe limit energy of the individual with the biological characteristics irradiated in a unit period;
t is the irradiation time of each frame period of the individual biological characteristics, namely the frame time of the synchronous time sequence pulse imaging mode of the exposure (integration) of the image imaging sensor and the near infrared LED light source irradiation;
f is the number of frames in a unit period, namely the frame frequency of the synchronous time sequence pulse imaging mode of the exposure (integration) of the image imaging sensor and the radiation of the near infrared LED light source;
e is the illumination intensity of each frame period of the individual with biological characteristics;
and D is object distance information.
The embodiment 1 of the invention is a combined optimization control method for realizing the safety limitation and high-quality interference-free biological characteristic image imaging of the biological characteristic individual in a unit period by a biological characteristic image acquisition system, and realizes the filtering of imaging interference such as background light and the like and imaging interference such as motion defocusing and the like, the acquisition of a high-quality interference-free biological characteristic imaging image and the safety limitation of the total radiation amount of the biological characteristic individual in the unit period.
The contents of the specific embodiments and technical features described in the present invention can be implemented within the scope of the same or equivalent understanding, and equivalents for the same purpose and implementing functions should be equally understood.
Finally, it is also noted that the above-mentioned lists merely illustrate a few specific embodiments of the invention. It is obvious that the invention is not limited to the above embodiments, but that many variations are possible. All modifications which can be derived or suggested by a person skilled in the art from the disclosure of the present invention are to be considered within the scope of the invention.