Detection method and detection system for fingerprint counterfeiting prevention

Abstract

The invention relates to a detection method and a detection system for fingerprint counterfeiting prevention, and the method comprises the steps: enabling a fingerprint part to be in contact with a fingerprint contact unit to form a closed-loop circuit, and carrying out the sampling of a voltage change; detecting the voltage change, and determining a voltage change value; if the voltage change value is in a first preset voltage threshold section, determining that the fingerprint is a living fingerprint; and if the voltage change value is in a second preset voltage threshold section, determining that the fingerprint is a non-living fingerprint. According to the application, accurate identification of true and false fingerprints is realized through the voltage change value generated after the fingerprint component is contacted with the fingerprint contact unit, fingerprint counterfeiting can be effectively prevented, the accuracy of living fingerprint identification is improved, the cost is low, and the reliability is high.

Description

Technical Field

[0001] The present application relates to the field of fingerprint recognition, and in particular, to a detection method and a detection system for fingerprint anti-counterfeiting. Background Art

[0002] With the development of society and the advancement of science and technology, biometric recognition technology has been widely used in the field of security authentication. Among them, fingerprint recognition, as a mature biometric recognition technology, is widely used in access control systems, security authentication, personal information protection and other fields due to its uniqueness, non-replicability and convenience. However, traditional fingerprint recognition systems have certain hidden dangers in terms of security, especially the weak defense capability against forged fingerprints, which makes them vulnerable to fake fingerprint attacks.

[0003] Most existing fingerprint recognition systems rely only on matching fingerprint images, while ignoring the question of whether the fingerprint is from a living person. This allows some people to easily deceive the fingerprint recognition system by making fake fingerprint molds, etc., causing security risks. Therefore, how to effectively distinguish between live fingerprints and fake fingerprints and improve the security and reliability of fingerprint recognition systems has become an urgent problem to be solved in the current fingerprint recognition technology field. Summary of the invention

[0004] The purpose of the present application is to provide a detection method and a detection system for fingerprint anti-counterfeiting, so as to solve the problem that the existing fingerprint detection fails to distinguish between live fingerprints and fake fingerprints, which directly affects the response and recognition speed of live fingerprints.

[0005] In order to solve the above problems, the present application adopts the following technical solutions:

[0006] The first aspect of the present application provides a detection method for fingerprint anti-counterfeiting, and the detection method for fingerprint anti-counterfeiting includes:

[0007] After the fingerprint component is brought into contact with the fingerprint contact unit to form a closed-loop circuit, a voltage change is sampled;

[0008] Detecting the voltage change and determining a voltage change value;

[0009] If the voltage change value is within the first preset voltage threshold range, the fingerprint is determined to be a live fingerprint;

[0010] If the voltage change value is within the second preset voltage threshold section, the fingerprint is determined to be a non-living fingerprint.

[0011] Preferably, the fingerprint anti-counterfeiting detection method further includes:

[0012] The voltage change is sampled through a sampling resistor.

[0013] Preferably, the fingerprint anti-counterfeiting detection method further includes:

[0014] determining the resistivity characteristic of the fingerprint component according to the voltage change value;

[0015] The counterfeit material of the fingerprint component is determined according to the resistivity characteristic of the fingerprint component.

[0016] Preferably, the fingerprint anti-counterfeiting detection method further includes:

[0017] Obtaining a temperature coefficient of the fingerprint component;

[0018] Acquiring the conductivity of the fingerprint component;

[0019] The counterfeit material of the fingerprint component is determined according to the temperature coefficient or the conductivity of the fingerprint component.

[0020] Preferably, the fingerprint anti-counterfeiting detection method further includes:

[0021] The fingerprint contact unit is configured as a metal ring; the metal ring is provided with a positive contact and a negative contact and the metal ring includes two or more metal ring segments;

[0022] Alternatively, the metal ring includes an inner ring and an outer ring, and the inner ring and the outer ring have opposite polarities.

[0023] Preferably, before detecting the voltage change and determining the voltage change value, the fingerprint anti-counterfeiting detection method includes:

[0024] Preset reference voltage;

[0025] If the sampled voltage change is greater than the reference voltage, the voltage comparator is controlled to output a signal to the lock MCU;

[0026] Control the lock MCU to wake up the fingerprint MCU and power on the fingerprint MCU;

[0027] The ADC detection port of the fingerprint MCU is controlled to detect the voltage change and determine the voltage change value.

[0028] Preferably, the detecting the voltage change and determining the voltage change value comprises:

[0029] The voltage change is subjected to analog-to-digital conversion control to determine the voltage change value.

[0030] The present application also provides a detection system for fingerprint anti-counterfeiting, and the detection system for fingerprint anti-counterfeiting includes:

[0031] A fingerprint sampling module, used to sample voltage changes after the fingerprint component is brought into contact with the fingerprint contact unit to form a closed-loop circuit;

[0032] A voltage detection module, used to detect the voltage change and determine the voltage change value;

[0033] A first identification module, configured to determine that the fingerprint is a live fingerprint if the voltage change value is within a first preset voltage threshold range;

[0034] The second identification module is used to determine that the fingerprint is a non-living fingerprint if the voltage change value is within a second preset voltage threshold section.

[0035] Preferably, the MCU includes a lock MCU and a fingerprint MCU, and the detection system for fingerprint anti-counterfeiting includes a reference voltage unit and a voltage comparison unit, the reference voltage unit is used to preset a reference voltage, and the voltage comparison unit is used to compare the sampled voltage change with the reference voltage, wherein when the voltage change is greater than the reference voltage, the lock MCU powers on the fingerprint MCU.

[0036] Preferably, the fingerprint anti-counterfeiting detection system comprises a warning unit, and when the voltage change is in the second preset voltage threshold section, the warning unit issues a fingerprint warning.

[0037] Compared with the prior art, the beneficial effect of the present application is that: after the fingerprint component is in contact with the fingerprint contact unit to form a closed-loop circuit, the voltage change is sampled; the voltage change is detected to determine the voltage change value; if the voltage change value is in the first preset voltage threshold section, the fingerprint is determined to be a live fingerprint; if the voltage change value is in the second preset voltage threshold section, the fingerprint is determined to be a non-live fingerprint. Therefore, the present application realizes accurate identification of true and false fingerprints through the voltage change value generated after the fingerprint component is in contact with the fingerprint contact unit, which can effectively prevent fingerprint counterfeiting, improve the accuracy of live fingerprint identification, and has low cost and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A flow chart of a fingerprint anti-counterfeiting detection method provided in an embodiment of the present application;

[0039] Figure 2 A flowchart of another fingerprint anti-counterfeiting detection method provided in an embodiment of the present application;

[0040] Figure 3 A corresponding relationship diagram of resistivity characteristics, temperature coefficient and conductivity when different fingerprint components and fingerprint contact units are in contact with each other provided in the embodiment of the present application;

[0041] Figure 4A schematic diagram of the structure of a fingerprint module provided in an embodiment of the present application;

[0042] Figure 5 A schematic diagram of the structure of another fingerprint module provided in an embodiment of the present application;

[0043] Figure 6 The first embodiment provided for the embodiments of the present application;

[0044] Figure 7 The second embodiment provided for the embodiments of the present application;

[0045] Figure 8 The third embodiment provided for the embodiments of the present application;

[0046] Fig. 9 A fourth embodiment provided for the embodiments of the present application;

[0047] Fig.10 An implementation method of sampling voltage of true and false fingerprints without a voltage comparator provided in an embodiment of the present application;

[0048] Fig.11 An implementation method of the true and false fingerprint sampling voltage when a voltage comparator is provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0050] It should be noted that, in the absence of conflict, the embodiments and technical features in the embodiments of the present application can be combined with each other, and the detailed description in the specific implementation method should be understood as an explanation of the purpose of the present application and should not be regarded as an improper limitation on the present application.

[0051] It should be understood that the orientation or position relationship is based on the orientation or position relationship shown in the drawings. These orientation terms are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application.

[0052] It should be noted that the fingerprint anti-counterfeiting detection method of the embodiment of the present application can be used for fingerprint locks, fingerprint scanners, smart phones and other devices, including but not limited to the types enumerated above. In order to avoid repetitive statements, the following description is based on the fingerprint lock as an application scenario, which should not be understood as limiting the scope of protection of the present application.

[0053] See also Figure 1 , Figure 1 A flow chart of a fingerprint anti-counterfeiting detection method provided in an embodiment of the present application.

[0054] The present application embodiment provides a detection method for fingerprint anti-counterfeiting, and the detection method for fingerprint anti-counterfeiting includes:

[0055] S1, after the fingerprint component is brought into contact with the fingerprint contact unit to form a closed-loop circuit, the voltage change is sampled;

[0056] Specifically, in this embodiment, the fingerprint component includes a live finger and a simulated finger, wherein the material of the simulated finger includes but is not limited to graphene material, silicone material, silver material, copper material, glass material, etc., which is not specifically limited here.

[0057] Specifically, in this embodiment, when the fingerprint component is brought into contact with the fingerprint contact unit, a capacitor is formed between the fingerprint component and the fingerprint contact unit. Since there is a dielectric between the fingerprint component and the fingerprint contact unit, when a closed circuit is formed, the charge will be redistributed between the fingerprint component and the fingerprint contact unit, and the charge will flow between the positive and negative electrodes of the fingerprint contact unit to form an electric field, and the charge redistribution will cause the voltage to change.

[0058] S2. Detecting the voltage change and determining the voltage change value;

[0059] Specifically, in this embodiment, the voltage change is detected to determine the voltage change value, so as to subsequently identify whether the fingerprint component is a live fingerprint or a fake fingerprint through the voltage change value.

[0060] S3. If the voltage change value is within the first preset voltage threshold range, the fingerprint is determined to be a live fingerprint;

[0061] S4. If the voltage change value is within the second preset voltage threshold range, the fingerprint is determined to be a non-living fingerprint.

[0062] Specifically, in this embodiment, since the voltage changes generated by the live fingerprint and the fingerprint components of different materials after contacting the fingerprint contact unit are different, the present application determines whether the fingerprint component is a live fingerprint according to the preset voltage threshold segment range within which the voltage change value falls.

[0063] In summary, the present application provides a detection method for fingerprint anti-counterfeiting. In this solution, after the fingerprint component is in contact with the fingerprint contact unit to form a closed-loop circuit, the voltage change is sampled; the voltage change is detected to determine the voltage change value; if the voltage change value is in the first preset voltage threshold section, the fingerprint is determined to be a live fingerprint; if the voltage change value is in the second preset voltage threshold section, the fingerprint is determined to be a non-live fingerprint. Therefore, the present application realizes accurate identification of true and false fingerprints through the voltage change value generated after the fingerprint component contacts the fingerprint contact unit, which can effectively prevent fingerprint counterfeiting and improve the accuracy of live fingerprint identification, with low cost and high reliability.

[0064] Based on the above embodiments:

[0065] As a preferred embodiment, the fingerprint anti-counterfeiting detection method further includes:

[0066] The voltage change is sampled through a sampling resistor.

[0067] Specifically, in this embodiment, when a fingerprint component such as a live fingerprint or a fake fingerprint contacts the fingerprint contact unit, a voltage difference is caused, the sampling resistor is connected in parallel with the fingerprint component, and the voltage across the sampling resistor also changes accordingly. The sampling voltage transmits the collected voltage change value to the next component for voltage change value detection.

[0068] It is worth noting that, in another preferred embodiment, voltage change sampling can also be performed through existing sampling chips, modules, etc., which are not specifically limited here.

[0069] It can be understood that in this embodiment, different resistance values ​​of the sampling resistors affect the final detection value of the voltage change ADC voltage. The MCU determines the true or false fingerprint based on the change value of the ADC voltage. The resistance value of the sampling resistor is not specifically limited here.

[0070] See also Figure 2 , Figure 2 A flowchart of another fingerprint anti-counterfeiting detection method provided in an embodiment of the present application.

[0071] See also Figure 3 , Figure 3 A corresponding relationship diagram of resistivity characteristics, temperature coefficient and conductivity when different fingerprint components and fingerprint contact units are in contact is provided in an embodiment of the present application.

[0072] As a preferred embodiment, the fingerprint anti-counterfeiting detection method further includes:

[0073] S5, determining the resistivity characteristic of the fingerprint component according to the voltage change value;

[0074] S6. Determine the counterfeit material of the fingerprint component according to the resistivity characteristics of the fingerprint component.

[0075] Specifically, resistivity is a measure of how much a material hinders the flow of electric current, which is directly related to the conductivity of the material.

[0076] Specifically, in this embodiment, when the fingerprint component contacts the fingerprint contact unit, the resistivity characteristics of fingerprint components of different materials are different, and the voltage change values ​​generated are also different. Therefore, the present invention obtains the relationship between the sampling resistor and the voltage through the voltage change value and the resistance value of the sampling resistor, analyzes the material of the fake fingerprint, and obtains the result.

[0077] As a preferred embodiment, the fingerprint anti-counterfeiting detection method further includes:

[0078] Obtaining a temperature coefficient of the fingerprint component;

[0079] Acquiring the conductivity of the fingerprint component;

[0080] The counterfeit material of the fingerprint component is determined according to the temperature coefficient or the conductivity of the fingerprint component.

[0081] Specifically, conductivity is a measure of the material's ability to conduct electricity, usually expressed in Si emens / m (Siemens per meter), or expressed as the reciprocal of resistivity. The conductivity of different materials varies greatly, with metals generally having high conductivity and insulating materials being almost non-conductive.

[0082] Specifically, the temperature coefficient refers to the degree to which the resistance value of a material changes with temperature. Different materials have different temperature coefficients. For example, the temperature coefficient of metals is usually small, while the temperature coefficient of some plastics or ceramics is large.

[0083] Specifically, in this embodiment, when the fake fingerprint component contacts the fingerprint contact unit, the system detects the change in resistivity through the flow of current. Since the resistivity of the fake fingerprint component is different from that of the live fingerprint, the present application can judge the authenticity of the fingerprint by comparing the difference between the two. By analyzing the voltage change when the fingerprint component contacts the detection unit, the resistivity characteristics of the fingerprint component can be inferred, and then its material can be determined. The resistivity characteristics of the live fingerprint, such as temperature coefficient, conductivity and other characteristics, are difficult for fake fingerprint components to fully replicate. Therefore, the present application can achieve accurate identification and measurement analysis of fake fingerprints.

[0084] Specifically, in one embodiment, the present application can be applied in a fingerprint recognition system, where the system uploads the counterfeit fingerprint component materials to the background for registration and recording, so that the user can obtain relevant information of the counterfeit fingerprint component materials and realize human-computer interaction.

[0085] See also Figure 4 , Figure 4 A schematic diagram of the structure of a fingerprint module provided in an embodiment of the present application.

[0086] As a preferred embodiment, the fingerprint anti-counterfeiting detection method further includes:

[0087] The fingerprint contact unit is configured as a metal ring; the metal ring is provided with a positive contact and a negative contact and the metal ring includes two or more metal ring segments;

[0088] Alternatively, the metal ring includes an inner ring and an outer ring, and the inner ring and the outer ring have opposite polarities.

[0089] Specifically, in one embodiment, the fingerprint contact unit is configured as a metal ring, the metal ring is provided with a positive contact and a negative contact, and the metal ring includes two metal ring segments.

[0090] In one embodiment, see Figure 5 The metal ring includes an inner ring and an outer ring, wherein the inner ring is a positive pole and the outer ring is a negative pole, or the inner ring is a positive pole and the outer ring is a negative pole.

[0091] Specifically, when a fingerprint component such as a live fingerprint or a fake fingerprint contacts the positive and negative electrodes of the metal ring or when the fingerprint component contacts the upper end faces of the outer ring and the inner ring of the metal ring at the same time, a capacitor is formed between the fingerprint component and the metal ring. Among them, the size of the capacitor depends on the contact area between the fingerprint component and the metal ring, the distance between the two, and the dielectric constant of the medium. Since there is a dielectric between the fingerprint component and the metal ring, when a closed circuit is formed, the charge will be redistributed between the metal ring, the fingerprint component and the contact medium, and the charge will flow between the positive and negative electrodes of the metal ring to form an electric field. Therefore, the redistribution of the charge will cause a voltage difference between the positive and negative electrodes of the metal ring, thereby causing a change in the voltage signal when the fingerprint component is placed on the fingerprint contact unit. In this embodiment, the difference in dielectric constant between the live fingerprint or the fake fingerprint and the metal ring causes a difference in voltage difference. Therefore, the present application can effectively prevent fingerprint fraud and improve the accuracy of live fingerprint recognition by distinguishing true and false fingerprints through voltage difference recognition.

[0092] It is worth noting that the metal ring can also be set to 3 sections, 4 sections, 5 sections, 6 sections, etc., which is not specifically limited here. In addition, the metal ring of the present application is annular, and in another embodiment, it can also be set to a square shape, an elliptical shape or a special-shaped column, etc., which is not specifically limited here.

[0093] It can be understood that in the present application, the metal ring is divided into two metal segments, which effectively improves the accuracy of true and false fingerprint identification without changing the existing process, and the process is simple and low-cost.

[0094] In addition, the metal ring of the present application can be configured as other components with positive and negative electrodes, all of which are within the protection scope of the present application and are not specifically limited here.

[0095] As a preferred embodiment, before detecting the voltage change and determining the voltage change value, the fingerprint anti-counterfeiting detection method includes:

[0096] Preset reference voltage;

[0097] If the sampled voltage change is greater than the reference voltage, the voltage comparator is controlled to output a signal to the lock MCU;

[0098] Control the lock MCU to wake up the fingerprint MCU and power on the fingerprint MCU;

[0099] The ADC detection port of the fingerprint MCU is controlled to detect the voltage change and determine the voltage change value.

[0100] In order to better understand the fingerprint anti-counterfeiting detection circuit of the embodiment of the present application, its working principle is described below.

[0101] In one embodiment, the resistance value change is sampled through a sampling resistor connected to the metal ring. Since the sampling resistor is connected to the ADC interface in the MCU, it will affect the ADC voltage value change. The MCU determines the true or false fingerprint based on the preset voltage value and the sampling voltage change.

[0102] The MCU includes two parts: the lock MCU and the fingerprint MCU. When a fingerprint component such as a live finger or a fake fingerprint component contacts the metal ring detection on the fingerprint lock, a voltage change is generated. The sampling resistor samples the voltage change and outputs the sampled voltage. The voltage signal is transmitted to the voltage comparator. The voltage comparator detects the voltage change and compares it with the set reference voltage. When the voltage exceeds the set threshold, the voltage comparator outputs a high-level signal, thereby waking up the lock MCU, and then opening the lock MOS to power on the fingerprint MCU. At the same time, the sampled voltage is transmitted to the ADC voltage detection port, and the ADC voltage detection port determines the ADC value of the voltage change. The fingerprint MCU determines that the voltage change value is in the first preset voltage threshold segment or the second preset voltage threshold segment to achieve the purpose of confirming that the fingerprint component is a live finger or a fake fingerprint component.

[0103] Specifically, in this embodiment, by introducing a comparator to judge the relationship between the sampling voltage and the preset reference voltage, the fingerprint MCU is precisely controlled, ensuring that the true and false fingerprints (live fingerprints and false fingerprints) are identified under appropriate voltage conditions, thereby improving the accuracy of fingerprint anti-false identification. Live fingerprints are characterized by the fingerprints of the fingers input by the user; false fingerprints are characterized by non-live fingerprints, including but not limited to duplicate fingerprints, illegal fingerprints of other users, etc.

[0104] Specifically, in this embodiment, when a live finger contacts two contacts of the metal ring 1 at the same time, the voltage change value after sampling by the sampling resistor and voltage detection is 0.18V-0.76V, which exceeds the comparator reference level of 0.15V. The comparator will output a high level to wake up the lock MCU to power on the fingerprint MCU. The ADC port of the fingerprint MCU will detect the ADC level. If the ADC level is between 0.18V-0.76V (including the endpoint value), it is judged as a live fingerprint, and the fingerprint MCU will continue to perform the fingerprint recognition action. Otherwise, if the ADC level is not in the range of 0.18V-0.76V (the range can be customized), it is judged as a false fingerprint, and the fingerprint MCU will stop performing the fingerprint recognition action.

[0105] When a fake fingerprint contacts the two contacts of the metal ring 1 at the same time, and the sampling resistor obtains a sampling voltage of 1.5V-3V, which exceeds the comparator reference level (for example, the reference level is 0.15V), the comparator will output a high level to wake up the lock MCU and power on the fingerprint MCU. The ADC port of the fingerprint MCU will detect the ADC level. If the ADC level is in the range of 1.5V-3V, it is judged as a fake fingerprint, and the fingerprint MCU will stop executing the fingerprint recognition action.

[0106] As a preferred embodiment, the detecting the voltage change and determining the voltage change value comprises:

[0107] The voltage change is subjected to analog-to-digital conversion control to determine the voltage change value.

[0108] Specifically, in this embodiment, the voltage detection in this application is implemented through an analog-to-digital conversion circuit. The analog-to-digital conversion circuit can be set as an independent analog-to-digital conversion IC or an analog-to-digital conversion circuit or software built into the MCU. The model of the analog-to-digital conversion IC and the structure of the analog-to-digital conversion circuit are not specifically limited here.

[0109] The present application also provides a detection system for fingerprint anti-counterfeiting, and the detection system for fingerprint anti-counterfeiting includes:

[0110] A fingerprint sampling module, used to sample voltage changes after the fingerprint component is brought into contact with the fingerprint contact unit to form a closed-loop circuit;

[0111] A voltage detection module, used to detect the voltage change and determine the voltage change value;

[0112] A first identification module, configured to determine that the fingerprint is a live fingerprint if the voltage change value is within a first preset voltage threshold range;

[0113] The second identification module is used to determine that the fingerprint is a non-living fingerprint if the voltage change value is within a second preset voltage threshold section.

[0114] As a preferred embodiment, the MCU includes a lock MCU and a fingerprint MCU, and the detection system for fingerprint anti-counterfeiting includes a reference voltage unit and a voltage comparison unit, the reference voltage unit is used to preset a reference voltage, and the voltage comparison unit is used to compare the sampled voltage change with the reference voltage, wherein when the voltage change is greater than the reference voltage, the lock MCU powers on the fingerprint MCU.

[0115] As a preferred embodiment, the fingerprint anti-counterfeiting detection system includes a warning unit, and when the voltage change is in the second preset voltage threshold section, the warning unit issues a fingerprint warning.

[0116] In some embodiments, the detection system for fingerprint anti-counterfeiting includes a warning unit, and when the sampling voltage is not within the preset voltage threshold segment, the warning unit issues a fingerprint warning. Through the setting of the warning unit, when the sampling voltage is not within the preset voltage threshold segment, the system can issue a fingerprint warning to promptly remind the user of operating errors or abnormalities, thereby increasing the security of the system. When the sampling voltage is abnormal, the fingerprint warning issued by the warning unit can prevent illegal opening and protect the safety of property.

[0117] Example 1

[0118] See also Figure 6 , Figure 6 This is an implementation of a fingerprint anti-counterfeiting detection control circuit of the present application.

[0119] Specifically, in this embodiment, when a live finger contacts the two contacts M+M- of the metal ring at the same time, the voltage change value is collected by the sampling resistor connected to the metal ring and then transmitted to the ADC port of the fingerprint MCU. The ADC port of the fingerprint MCU detects the ADC level. If the ADC level is in the range of 0.18V-0.76V, the fingerprint MCU determines it as a live fingerprint, and the fingerprint MCU continues to perform the fingerprint recognition action; if the ADC level is not in the range of 0.18V-0.76V, the fingerprint MCU determines it as a false fingerprint, and the fingerprint MCU stops performing the fingerprint recognition action.

[0120] Specifically, the live fingerprint voltage value range of 0.18V-0.76V in the present application is the voltage range of the live finger in contact with the metal contact. The voltage range can be set according to the structure of the fingerprint contact unit and is not specifically limited here.

[0121] Specifically, in this embodiment, when a fake fingerprint contacts the two contacts M+M- of the metal ring at the same time, the voltage change value is collected by the sampling resistor connected to the metal ring and then transmitted to the ADC port of the fingerprint MCU. The ADC port of the fingerprint MCU detects the ADC level. If the ADC level is between 1.5V and 3V, the fingerprint MCU determines it as a fake fingerprint, and the fingerprint MCU stops executing the fingerprint recognition action.

[0122] Specifically, the voltage value range of 1.5V-3V in the present application is the voltage range for the fake fingerprint made of silicone material to contact the metal contact. The voltage range can be set according to the material of the fake fingerprint and the structure of the fingerprint contact unit, and is not specifically limited here.

[0123] Example 2

[0124] See also Figure 7 , Figure 7 This is an implementation of a fingerprint anti-counterfeiting detection control circuit of the present application.

[0125] Specifically, in this embodiment, when a live finger contacts the two contacts M+M- of the metal ring at the same time, the voltage change value is collected by the sampling resistor connected to the metal ring and then transmitted to the voltage comparator. If the voltage change value is greater than the reference level of the voltage comparator B, the voltage comparator B outputs a high level to wake up the lock MCU to power on the fingerprint MCU, and the ADC port of the fingerprint MCU detects the ADC level. If the ADC level is in the range of 0.18V-0.76V, the fingerprint MCU determines it as a live fingerprint, and the fingerprint MCU continues to perform the fingerprint recognition action. Otherwise, if the ADC level is not in the range of 0.18V-0.76V, the fingerprint MCU determines it as a false fingerprint, and the fingerprint MCU stops performing the fingerprint recognition action.

[0126] Specifically, the live fingerprint voltage value range of 0.18V-0.76V in the present application is the voltage range of the live finger in contact with the metal contact. The voltage range can be set according to the structure of the fingerprint contact unit and is not specifically limited here.

[0127] Specifically, in this embodiment, when a fake fingerprint contacts the two contacts M+M- of the metal ring at the same time, the voltage change value is collected by the sampling resistor connected to the metal ring and then transmitted to the voltage comparator. If the voltage change value is greater than the reference level of the voltage comparator B, the voltage comparator B outputs a high level to wake up the lock MCU to power on the fingerprint MCU, and the ADC port of the fingerprint MCU detects the ADC level. If the ADC level is in the range of 1.5V-3V, the fingerprint MCU determines it as a fake fingerprint, and the fingerprint MCU stops executing the fingerprint recognition action.

[0128] Specifically, the voltage value range of 1.5V-3V in the present application is the voltage range for the fake fingerprint made of silicone material to contact the metal contact. The voltage range can be set according to the material of the fake fingerprint and the structure of the fingerprint contact unit, and is not specifically limited here.

[0129] Example 3

[0130] See also Figure 8 , Figure 8 This is an implementation of a fingerprint anti-counterfeiting detection control circuit of the present application.

[0131] Specifically, in this embodiment, when a live finger touches the two contacts M+M- of the metal ring at the same time, the voltage change value is collected by the sampling resistor connected to the metal ring and then transmitted to the analog-to-digital conversion IC. The analog-to-digital conversion IC detects the ADC level. If the ADC level is in the range of 0.18V-0.76V, the fingerprint MCU determines it as a live fingerprint, and the fingerprint MCU continues to perform the fingerprint recognition action. Otherwise, if the ADC level is not in the range of 0.18V-0.76V, the fingerprint MCU determines it as a false fingerprint, and the fingerprint MCU stops performing the fingerprint recognition action.

[0132] Specifically, the live fingerprint voltage value range of 0.18V-0.76V in the present application is the voltage range of the live finger in contact with the metal contact. The voltage range can be set according to the structure of the fingerprint contact unit and is not specifically limited here.

[0133] Specifically, in this embodiment, when a fake fingerprint contacts the two contacts M+M- of the metal ring at the same time, the voltage change value is collected by the sampling resistor connected to the metal ring and then transmitted to the analog-to-digital conversion IC. The analog-to-digital conversion IC detects the ADC level. If the ADC level is in the range of 1.5V-3V, the fingerprint MCU determines it as a fake fingerprint, and the fingerprint MCU stops executing the fingerprint recognition action.

[0134] Specifically, the voltage value range of 1.5V-3V in the present application is the voltage range for the fake fingerprint made of silicone material to contact the metal contact. The voltage range can be set according to the material of the fake fingerprint and the structure of the fingerprint contact unit, and is not specifically limited here.

[0135] Example 4

[0136] See also Fig. 9 , Fig. 9 This is an implementation of a fingerprint anti-counterfeiting detection control circuit of the present application.

[0137] Specifically, in this embodiment, the implementation method is similar to that of Embodiment 1, except that the ADC of the fingerprint MCU is replaced with the ADC of the lock MCU. After the lock MCU determines whether the fingerprint is true or false, if it is a true fingerprint, it calls the fingerprint module to perform subsequent work. Otherwise, the lock MCU does not call the fingerprint module, or directly gives interaction data to prompt a false fingerprint warning.

[0138] See also Fig.10 , Fig.10 This is an implementation method of the true and false fingerprint sampling voltage without a voltage comparator in the present application.

[0139] Specifically, without voltage comparator: true and false fingerprint sampling voltage = 300K / (300K+fingerprint impedance)*3.3V, where 300K is an example resistance value of the sampling resistor.

[0140] Specifically, in this embodiment, the fingerprint impedance is generated by a real fingerprint or a fake fingerprint, and the real fingerprint is human skin, and the resistance value is generally greater than 1M. Fake fingerprints generally cannot reach more than 1M because the materials used are different from skin. Different materials have different impedances, so this application can roughly derive the type of material based on the material impedance value.

[0141] See also Fig.11 , Fig.11 This is an implementation method of the true and false fingerprint sampling voltage when there is a voltage comparator in the present application.

[0142] Specifically, there is a voltage comparator: Voltage comparator reference voltage = 100K / (100K+2M)*3.3V = 0.15V

[0143] Specifically, in this embodiment, a reference voltage value of 0.15V is obtained by the voltage comparator as shown in the circuit diagram, and is compared with the two contacts M+M- of the contact metal ring and the sampling voltage obtained by the sampling resistor.

[0144] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the same. Although the present application has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present application.

Claims

1. A fingerprint anti-counterfeiting detection method, characterized in that: The fingerprint anti-counterfeiting detection method comprises: After the fingerprint component is brought into contact with the fingerprint contact unit to form a closed-loop circuit, a voltage change is sampled; Detecting the voltage change and determining a voltage change value; If the voltage change value is within the first preset voltage threshold range, the fingerprint is determined to be a live fingerprint; If the voltage change value is within the second preset voltage threshold section, the fingerprint is determined to be a non-living fingerprint.

2. A fingerprint anti-counterfeiting detection method according to claim 1, characterized in that: The fingerprint anti-counterfeiting detection method further includes: The voltage change is sampled through a sampling resistor.

3. A fingerprint anti-counterfeiting detection method according to claim 2, characterized in that: The fingerprint anti-counterfeiting detection method further includes: determining the resistivity characteristic of the fingerprint component according to the voltage change value; The counterfeit material of the fingerprint component is determined according to the resistivity characteristic of the fingerprint component.

4. A fingerprint anti-counterfeiting detection method according to claim 3, characterized in that: The fingerprint anti-counterfeiting detection method further includes: Obtaining a temperature coefficient of the fingerprint component; Acquiring the conductivity of the fingerprint component; The counterfeit material of the fingerprint component is determined according to the temperature coefficient or the conductivity of the fingerprint component.

5. A fingerprint anti-counterfeiting detection method according to claim 1, characterized in that: The fingerprint anti-counterfeiting detection method further includes: The fingerprint contact unit is configured as a metal ring; The metal ring is provided with a positive contact and a negative contact and the metal ring comprises 2 or more metal ring segments; Alternatively, the metal ring includes an inner ring and an outer ring, and the inner ring and the outer ring have opposite polarities.

6. A fingerprint anti-counterfeiting detection method according to claim 2, characterized in that: Before detecting the voltage change and determining the voltage change value, the fingerprint anti-counterfeiting detection method includes: Preset reference voltage; If the sampled voltage change is greater than the reference voltage, the voltage comparator is controlled to output a signal to the lock MCU; Control the lock MCU to wake up the fingerprint MCU and power on the fingerprint MCU; The ADC detection port of the fingerprint MCU is controlled to detect the voltage change and determine the voltage change value.

7. A fingerprint anti-counterfeiting detection method according to claim 1, characterized in that: The detecting the voltage change and determining the voltage change value comprises: The voltage change is subjected to analog-to-digital conversion control to determine the voltage change value.

8. A fingerprint anti-counterfeiting detection system, characterized in that: A fingerprint anti-counterfeiting detection method applied to any one of claims 1 to 7, wherein the fingerprint anti-counterfeiting detection system comprises: A fingerprint sampling module, used to sample voltage changes after the fingerprint component is brought into contact with the fingerprint contact unit to form a closed-loop circuit; A voltage detection module, used to detect the voltage change and determine the voltage change value; A first identification module, configured to determine that the fingerprint is a live fingerprint if the voltage change value is within a first preset voltage threshold range; The second identification module is used to determine that the fingerprint is a non-living fingerprint if the voltage change value is within a second preset voltage threshold section.

9. A fingerprint anti-counterfeiting detection system according to claim 6, characterized in that: The MCU includes a lock MCU and a fingerprint MCU, and the detection system for fingerprint anti-counterfeiting includes a reference voltage unit and a voltage comparison unit, the reference voltage unit is used to preset a reference voltage, and the voltage comparison unit is used to compare the sampled voltage change with the reference voltage, wherein when the voltage change is greater than the reference voltage, the lock MCU powers on the fingerprint MCU.

10. A fingerprint anti-counterfeiting detection system according to claim 9, characterized in that: The fingerprint anti-counterfeiting detection system comprises a warning unit, and when the voltage change is in the second preset voltage threshold section, the warning unit issues a fingerprint warning.

Images