KR20100002606A - Fingerprint authentication method - Google Patents

Abstract

PURPOSE: An authentication method of a fingerprint approval device for performing the fingerprint certification process about the candidate fingerprint of the high similarity are provided to reduce the rate of rejecting authentication and the rate of authenticating wrongly the other person by performing fingerprint input twice. CONSTITUTION: A fingerprint input unit acquires a fingerprint image from a user fingerprint(S201). An authentication unit determines the existence of the registered fingerprint in which the matching value of the user fingerprint is the first qualification standard value. The registered fingerprint more than the first qualification standard value is processed as the final authentication success(S203). The authentication unit processes the fingerprint data as candidate fingerprint data(S205).

Description

Authentication method of fingerprint authentication device {Fingerprint Authentication Method}

According to the present invention, if authentication is performed by performing an authentication process on a fingerprint for which authentication is requested, the entire fingerprint is registered, the candidate fingerprint is extracted by extracting some fingerprints having a high similarity among the fingerprints registered based on the first execution result. The present invention relates to an authentication method of a fingerprint authentication device which improves another authentication rate and a rejection rate by performing a fingerprint authentication process again.

The fingerprint authentication device performs a verification process by registering the user's fingerprints into a database and then comparing the newly input fingerprint data with the registered fingerprint data stored in the database when the user attempts to authenticate. .

Here, the fingerprint data refers to feature point data extracted from a fingerprint image obtained by a fingerprint input unit from a user's finger. Fingerprint refers to the pattern of skin on the inside of the fingertip or traces left by it, and can be commonly used with fingerprint data only in terms of the fixed form of the image. The fingerprint authentication device compares two comparison target fingerprint data, that is, feature point data, and determines that the fingerprint is the same when there is a certain degree of similarity or more. Scoring the same or similar degree between two pieces of fingerprint data is called a matching score. If the matching value is greater than or equal to the predetermined authentication reference value, it is determined as the same fingerprint.

On the other hand, the user authentication method using a conventional fingerprint authentication device includes a 1: 1 verification (Verification) and 1: N authentication (Identification). 1: 1 authentication receives a user's ID from the user and determines whether or not the matching value comparing the user fingerprint registered with the ID with the newly input fingerprint for authentication is equal to or greater than the authentication reference value.

On the other hand, 1: N authentication is a method of performing an authentication process based on the entire registered fingerprint data without inputting an ID of a user. For example, a method of searching and authenticating a corresponding user is obtained by comparing N fingerprints by comparing a fingerprint input for authentication with the entire registered fingerprint and finding a registered fingerprint that is equal to or greater than an authentication reference value among the matching values. Due to its characteristics, this type of authentication method has a high probability of false authentication (FAR: False Accept Ratio) if it is not your own fingerprint. There is also a problem that the probability of not being authenticated (FRR: False Reject Ratio, also higher).

In other words, if the authentication standard value is too high, even though the fingerprint is your own, the quality of the fingerprint you entered is slightly lowered, resulting in a higher FRR, which is rejected. In order to solve such a problem, if the authentication standard value is lowered, the other person's false authentication rate (FAR), which is judged as the fingerprint of another person and authenticated by another person, is increased.

An object of the present invention, if the authentication is performed by performing the authentication process for the fingerprint for which authentication is requested to all registered fingerprints first, candidate fingerprints having some similarities among the fingerprints registered among the fingerprints registered on the basis of the first performing result. The present invention provides an authentication method of a fingerprint authentication device which improves another authentication rate and rejection rate by performing a fingerprint authentication process on a candidate fingerprint.

In order to achieve the above object, an authentication method of a fingerprint authentication device according to the present invention includes a first authentication processing of a successful authentication when a registration fingerprint having a matching value with a user fingerprint requested for authentication is equal to or greater than a first authentication reference value among a plurality of registration fingerprints. Second authentication step; And when the authentication fails in the first authentication step, determining whether the authentication succeeds again based on at least one candidate fingerprint in which the matching value with the authentication requested fingerprint among the plurality of registered fingerprints falls within a predetermined candidate range. The second authentication step.

Here, the maximum value of the candidate range is preferably smaller than the first authentication reference value.

The second authentication step may include re-acquiring a fingerprint image from a user and re-extracting feature point data; And if the maximum value of the matching values obtained by comparing the fingerprint data of the candidate fingerprint and the extracted feature point data is greater than or equal to a predetermined second authentication criterion value, processing the authentication success.

Here, the second authentication reference value is lower than the first authentication reference value, preferably a value located within the candidate range, furthermore, the second authentication reference value is lower than the first authentication reference value, and is a median value of the candidate range. It is preferable.

According to an embodiment, the first authentication step may include: obtaining a fingerprint image from a user and extracting feature point data; If the matched value obtained by comparing the extracted feature point data with one of the plurality of registered fingerprints is equal to or greater than the first authentication criterion value, it is determined to be an authentication success. Determining whether it is within a range; And repeating the determining until the matching value compared with the extracted feature point data in the plurality of registered fingerprints is equal to or greater than the first authentication reference value, and the matching value compared with the extracted feature point data in the plurality of registered fingerprints. If it is finally determined that there is no more than the first authentication reference value may include determining that the authentication in the first authentication step has failed last.

The authentication method of the fingerprint authentication device according to the present invention has a two-stage authentication system, and if the fingerprint state is poor, the fingerprint is input two times, thereby lowering the erroneous authentication rate and the rejection rate. Furthermore, in the second authentication step, the fingerprint authentication is not performed again based on the entire enrolled fingerprint data, but the entire authentication time is long by performing only the candidate enrolled fingerprint data that is determined to be higher than a certain level in the first authentication step. Prevents losing

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a block diagram of a fingerprint authentication device according to an embodiment of the present invention.

Referring to FIG. 1, the fingerprint authentication apparatus 100 includes a fingerprint input unit 110 for acquiring a fingerprint image from a user, a data storage unit 130 for storing registered fingerprint data, and a controller 150.

The fingerprint input unit 110 obtains a fingerprint image from a user and outputs the fingerprint image to the controller 150 according to various fingerprint image acquisition methods including optical, semiconductor, and the like. For example, in the case of the optical type, the fingerprint input unit 110 may include an optical device including a prism, a lens, and the like, and an image pickup device for fixing an image.

The data storage unit 130 stores fingerprint data (hereinafter referred to as "registered fingerprint data") of the user who has been registered through the registration process. Fingerprint data refers to feature point data extracted from a fingerprint image. In addition, the data storage unit 130 stores information on the registered user. This information includes the user's name and identifier (ID). According to an embodiment, the user information may include a separate authentication reference value mapped to the corresponding user. The authentication standard values are described again below. Hereinafter, for convenience of explanation, it is assumed that the number of registered fingerprint data is N.

The controller 150 controls the overall operation of the fingerprint authentication device 100 including fingerprint registration and authentication. Since the present invention relates to fingerprint authentication, details related to fingerprint registration will not be described below.

Referring to FIG. 1, the controller 150 includes a feature point extractor 151, a fingerprint matching unit 153, and an authentication unit 155 to control an authentication process of a user. As described above, the controller 150 illustrated in FIG. 1 may include a fingerprint registration unit related to fingerprint registration.

The feature point extractor 151 extracts feature point data from a fingerprint image input through the fingerprint input unit 110.

The fingerprint matching unit 153 receives the feature point data (ie, fingerprint data of the user's fingerprint requested for authentication) received by the user from the feature point extraction unit 151 and registers the data stored in the data storage unit 130. The matching value is calculated by comparing with the fingerprint data, and the calculated matching value is provided to the authenticator 155. The matching value is a score obtained by scoring the same or similar degree of two fingerprint data and can be obtained by various algorithms.

The method of providing a matching value to the authenticator 155 may vary depending on the authentication algorithm. In the first method, the fingerprint matching unit 153 may calculate the N matching values for all the N registered fingerprint data and provide them to the authenticator 155. Alternatively, the fingerprint matching unit 153 may calculate and provide one matching value sequentially in response to a request of the authentication unit 155, and calculate and provide up to N numbers depending on whether the authentication is successful.

The authentication unit 155 performs an authentication process for the user while comparing the matching value provided from the fingerprint matching unit 153 with a predetermined authentication reference value. The authentication reference value is a threshold value of a matching value for determining a user fingerprint input for fingerprint authentication as an authentication success. The authentication reference value is determined to be equal to or greater than the authentication reference value and authenticates the corresponding user. For example, if the possible range of the matching value is 0 to 9999 and the authentication reference value is 8000, the authenticator 155 may check the two fingerprint data (or, if there is registration fingerprint data having a matching value of 8000 or more with the requested fingerprint data). The fingerprint) is determined to be the same.

The authentication unit 155 uses a two-step authentication scheme, and thus uses a plurality of authentication reference values.

In the first authentication step, the registration fingerprint data having a matching value equal to or greater than a predetermined first authentication criterion value is searched, and if there is registration fingerprint data having a matching value equal to or greater than the first authentication criterion value, it is determined that authentication is successful. As described above in the fingerprint matching unit 153, the first authentication step may be applied in various ways.

In the second authentication step, if authentication fails in the first authentication step, candidate fingerprints (or candidate fingerprint data) that are determined to be most probable based on the first authentication result, not N total fingerprint data. Is made for. Here, the candidate fingerprints refer to registered fingerprints having a high similarity with the user fingerprint requested for authentication as compared with the first authentication step, and belonging to a predetermined 'candidate range' among N matching values calculated in the first authentication step. m pieces of registered fingerprint data (ie, candidate fingerprint data) corresponding to m (1 ≦ m ≦ N) matching values.

In addition, the second authentication step uses the fingerprint data generated by receiving a new fingerprint from the user again, and the predetermined second authentication is performed on the generated fingerprint data and m matching values recalculated for the m registered fingerprint data. By comparison with a reference value.

Here, the second authentication reference value may be the same value as the first authentication reference value or may be a different value. However, the candidate authentication range should be formed below the first authentication reference value, and these authentication reference values and candidate authentication ranges may be set by the user. This second authentication step is performed only for m registration fingerprint data belonging to a certain candidate group among all N registration fingerprint data in the state where authentication fails in the first authentication step, and furthermore, by using a newly input fingerprint, It is possible to lower the FAR and FRR.

In an embodiment, the first authentication reference value, the second authentication reference value, and the candidate authentication range may be equal to the following equation.

(Second certification reference value-α) ≤ candidate certification range <(second certification reference value + α)

1st certification reference value = 2nd certification reference value + α, α> 0

The second authentication reference values according to Equations 1 and 2 correspond to the intermediate values of the candidate authentication ranges, and the second authentication reference values become minimum matching values required for authentication. Therefore, when the second authentication reference value and α are set, the authentication candidate range and the first authentication reference value can be determined. For example, when the second authentication reference value is 6500 and α is 1500, the authentication candidate range is 5000 or more and less than 8000, and the first authentication reference value is 8000.

More specifically, the two-step authentication method of the authentication unit 155 will be described based on FIG. 2.

2 is a flowchart provided to explain an example of an authentication operation of an authentication unit. Hereinafter, the operation of the authenticator 155 will be described with reference to FIGS. 1 and 2. 2 will be described based on the second authentication step.

When the authentication process starts, the fingerprint input unit 110 proceeds to the first authentication step starting with obtaining a fingerprint image from the user's fingerprint (S201).

In the first authentication step, the authentication unit 155 determines whether there is a registration fingerprint among the registration fingerprints stored in the data storage unit 130 and having a matching value with the user fingerprint requested for authentication equal to or greater than the first authentication reference value. It is determined that the registered fingerprint that is equal to or greater than one authentication reference value is the same as the user fingerprint requested for authentication, and is processed as a final authentication success (S203).

The authentication unit 155 collects m candidate fingerprint data among the N registered fingerprint data when there is no matching value that is equal to or greater than the first authentication reference value when the authentication result authentication fails in step S201. As described above, the authentication unit 155 processes the registered fingerprint data whose matching value with the user fingerprint requested for authentication falls within the candidate range as candidate fingerprint data (or candidate fingerprints) (S205).

The fingerprint input unit 110 obtains the fingerprint image from the user again (S201), and the feature point extractor 151 extracts the feature point data from the newly acquired fingerprint image. To this end, the authenticator 155 may control the user to input the fingerprint again to be output as an image or a voice through a display unit (not shown) or a speaker (not shown) (S207).

The fingerprint matching unit 153 calculates m matching values by comparing the newly extracted feature point data with each of the m candidate fingerprint data. The fingerprint matching unit 153 provides the calculated m matching values to the authenticator 155 (S209).

The authentication unit 155 finds the highest matching value having the highest value among the matching values provided from the fingerprint matching unit 153, and determines whether the highest matching value is greater than or equal to the second authentication reference value (S211).

If the maximum matching value is greater than or equal to the second authentication reference value, the authentication unit 155 determines that the authentication is successful, and continues the subsequent work according to the authentication success. For example, the authentication unit 155 may control the door opening and closing unit (not shown) to open and close the door (S213).

If it is determined in step S211 that the highest matching value is not greater than or equal to the second authentication reference value, the authentication unit 155 determines that the authentication failed, and continues the subsequent work according to the authentication failure (S215).

According to an exemplary embodiment, when there is no candidate fingerprint data in step S205, the authenticator 155 may process the authentication failure without the second authentication step.

According to an embodiment, in steps S211 and S213, the authentication unit 155 does not immediately determine that the authentication succeeds even if the highest matching value is greater than or equal to the second authentication reference value, and the candidate fingerprint corresponding to the highest matching value (that is, the registered fingerprint). It can be checked whether there is a specially specified certification standard value. As a result of the determination, if there is an authentication criterion value specifically designated in the registered fingerprint, it may be again compared whether the highest matching value is equal to or greater than the authentication criterion value, and it may be determined whether authentication is successful according to the result.

This authentication method can be used, for example, for some users, in the case of requiring higher authentication than the general user, in order to make the contents of the work that can be handled by authentication wider or narrower than that of the general user. Therefore, it is preferable that the specially designated authentication reference value is a value at least higher than the second authentication reference value.

On the contrary, in steps S211 and S213, the authentication unit 155 does not immediately determine that the authentication fails even if the highest matching value is not greater than or equal to the second authentication reference value, and specifically for a candidate fingerprint (ie, a registered fingerprint) corresponding to the highest matching value. You can check whether there is a designated certification standard value. As a result of the determination, if there is an authentication criterion value specifically designated in the registered fingerprint, it may be again compared whether the highest matching value is equal to or greater than the authentication criterion value, and finally it may be determined whether the authentication is successful. In this case, it is preferable that the specially designated authentication reference value is at least lower than the second authentication reference value.

In the first authentication step corresponding to step S201, various algorithms may be used.

For example, unlike the second authentication step, the N registered fingerprint data stored in the data storage unit 130 and N matching fingerprints of the user fingerprints requested for authentication are not obtained all at once, and the N registered fingerprint data are sequentially obtained one by one. Compare with the user fingerprint requested for authentication.

When the fingerprint input unit 110 first obtains a fingerprint image from the user, the process of extracting the feature point data from the fingerprint image by the feature extractor 151 is the same. Subsequently, the fingerprint matching unit 153 calculates a matching value by comparing one of the N registered fingerprint data stored in the data storage unit 130 with the feature point data received from the feature point extraction unit 151, and calculates the matching value. It provides to the authenticator 155. The authenticator 155 compares the matching value provided from the fingerprint matching unit 153 with the first authentication criterion value, and determines that the authentication is successful when the authentication value is greater than or equal to the first authentication criterion value. If the matching value is not equal to or greater than the first authentication reference value, the authentication unit 155 requests the fingerprint matching unit 153 to calculate and provide a matching value for the next registered fingerprint data. This process is repeated until authentication is successful. Finally, if no matching value is equal to or greater than the first authentication reference value, the authentication unit 155 determines that the authentication fails, and prepares for the second authentication step. At this time, the fingerprint matching unit 153 finally calculates N matching values by comparing the total N registered fingerprint data with the user fingerprint requested for authentication.

Regarding the collection of candidate fingerprints related to the first authentication step, the authentication unit 155 immediately determines whether each matching value falls within the candidate range immediately after comparison with the first authentication reference value, so that step S205 is performed within step S201. It may belong. Alternatively, in step S201, the authentication unit 155, as a previous step of collecting candidate fingerprint data in step S205, immediately determines whether each matching value falls within the candidate range immediately after comparison with the first authentication reference value, and in step S205 May only perform a degree of reconfirming the candidate fingerprint.

As another authentication method that can be used in the first authentication step, the first authentication step, like the second authentication step, includes a total of N registered fingerprint data stored in the data storage unit 130 and the user fingerprint requested for authentication. A method of determining all the matching values N at once and determining whether the highest value among the obtained N matching values is greater than or equal to the first authentication reference value may be used. Candidate fingerprint data collection in step S205 may be obtained from N calculated matching values. 3 is a flowchart provided to explain an example of the first authentication step performed by the authentication unit.

When the authentication process is started, the fingerprint input unit 110 obtains a fingerprint image from the user (S301), and the feature point extractor 151 extracts feature point data from the fingerprint image (S303).

The fingerprint matching unit 153 calculates a matching value by comparing each of the plurality of registered fingerprint data stored in the data storage unit 130 with the feature point data received from the feature point extraction unit 151. The fingerprint matching unit 153 provides the calculated plurality of matching values to the authenticator 157 (S305).

The authentication unit 157 finds the highest matching value having the highest value among the matching values provided from the fingerprint matching unit 153 (S307), and determines whether the first authentication reference value is greater than or equal to (S309).

If the highest matching value is greater than or equal to the first authentication criterion value, it is determined that the authentication is successful, and subsequent work according to the authentication success is continued. For example, the authentication unit 157 may control the door opening and closing unit (not shown) to open and close the door (S311).

As a result of the determination in step S309, when the maximum matching value is smaller than the first authentication reference value, the authentication unit 157 does not immediately determine the authentication failure, and stores the user information on the registered fingerprint data in which the highest matching value is calculated. In step 130, the authentication reference value applied to the registered fingerprint data (ie, the registered user) is extracted.

The authentication unit 157 determines whether the highest matching value is greater than or equal to the extracted authentication reference value (S315), and if the extraction is greater than or equal to the extracted authentication reference value, determines that the authentication is successful (that is, the user of the authentication request and the registered fingerprint data are the same). do. If the highest matching value is smaller than the extracted authentication reference value, the authentication unit 157 determines that the authentication fails, and prepares for the second authentication step. (S317).

By the above method, the authentication process of the fingerprint recognition device 100 of the present invention is performed.

The invention can be implemented in methods, devices and systems. In addition, when the present invention is implemented in computer software, the components of the present invention may be replaced with code segments necessary for performing necessary operations. The program or code segment may be stored in a medium that can be processed by a microprocessor and transmitted as computer data coupled with carrier waves via a transmission medium or communication network.

Media that can be processed by the microprocessor include electronic circuits, semiconductor memory devices, ROMs, flash memory, electrically erasable programmable read-only memory (EEPROM), floppy disks, optical disks, Hard disks, fiber optics, wireless networks, and the like that can convey and store information. Computer data also includes data that can be transmitted over electrical network channels, optical fibers, electromagnetic fields, wireless networks, and the like.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the above-described specific embodiment, the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

1 is a block diagram of a fingerprint authentication device according to an embodiment of the present invention;

2 is a flowchart provided to explain an example of an authentication operation of an authentication unit; and

3 is a flowchart provided to explain an example of the first authentication step performed by the authentication unit.

Claims (4)

A first authentication step of processing a successful authentication when there is a registration fingerprint among a plurality of registration fingerprints, wherein a matching value with a user fingerprint requested for authentication is equal to or greater than a first authentication reference value; And In case of authentication failure in the first authentication step, second authentication for determining whether the authentication succeeds again based on at least one candidate fingerprint in which the matching value with the authentication requested fingerprint among the plurality of registered fingerprints falls within a predetermined candidate range. Include an authentication step, The maximum value of the candidate range is smaller than the first authentication reference value, The second authentication step, Reacquiring a fingerprint image from the user and re-extracting feature point data; And And if the maximum value of the matching values comparing the fingerprint data of the candidate fingerprint and the extracted feature point data is greater than or equal to a predetermined second authentication reference value, processing as a successful authentication. The method of claim 1, And wherein the second authentication reference value is lower than the first authentication reference value and is located within the candidate range. The method of claim 2, Wherein the second authentication reference value is lower than the first authentication reference value and is a median value of the candidate range. According to claim 1, The first authentication step, Obtaining a fingerprint image from the user and extracting feature point data; If the matched value obtained by comparing the extracted feature point data with one of the plurality of registered fingerprints is equal to or greater than the first authentication criterion value, it is determined to be an authentication success. If the matched value is not greater than or equal to the first authentication criterion value, the matching value is the candidate. Determining whether it is within a range; And The determining is repeated until the matching value compared with the extracted feature point data in the plurality of registered fingerprints is equal to or greater than the first authentication reference value, and the matching value compared with the extracted feature point data in the plurality of registered fingerprints is And if it is finally determined that there is no more than the first authentication reference value, determining that the authentication in the first authentication step has finally failed.

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