JP4592341B2 - Biometric authentication device - Google Patents

Description

  The present invention relates to a biometric information authentication apparatus, and more specifically, biometric information capable of creating one registered biometric information feature by highly accurately synthesizing highly reliable or highly useful feature points from a plurality of biometric information features. The present invention relates to an authentication device.

  In recent years, there has been an interest in the importance of security by identity verification, such as performing qualification authentication when entering or leaving a building or room. There are various methods such as authentication using a password as a method of identity verification. As one of the methods, an apparatus that performs authentication using unique biometric information such as a fingerprint is often used.

  For example, a fingerprint sensor having an area smaller than a finger is on the market for the purpose of mounting a biometric information authentication device such as a fingerprint on a mobile device. These fingerprint sensors are suitable for mounting because they are space-saving and inexpensive, but can read only a part of the entire fingerprint.

  Therefore, if there is a difference in the finger placement position when collating with the registered one, there is a problem that the fingerprints (patterns, feature points) of both do not match and the collation accuracy tends to be lowered. That is, the position where the finger is placed with respect to the fingerprint sensor is shifted, and data including a fingerprint of a portion not registered at the time of collation is input, so that it is rejected despite being a registered user. It may end up.

  In addition, regardless of the size of the fingerprint sensor, there is a problem that the area of the finger in contact with the sensor is not constant due to the posture variation when placing the finger on the sensor. Even in this case, since the collation areas are different, the same problem as that of rejecting the person due to misalignment occurs.

In a fingerprint authentication device, usually, a finger guide is provided at a fingerprint input unit to prevent imaging region fluctuations such as displacement, but it is difficult to prevent completely.
In view of this, several methods have been proposed in which a plurality of fingerprint images or a plurality of fingerprint feature point data are combined to register a fingerprint in an area larger than the sensor area so as to cope with a positional shift at the time of authentication.

JP 10-143663 A JP 2001-344604 A

In Patent Document 1, a method for registering fingerprint image data is proposed. However, feature points extracted when images are combined may be lost or changed by combining the images.
Therefore, the obtained registered fingerprint does not clearly represent the characteristics of the user's fingerprint, that is, is not suitable for authentication, and the matching accuracy may be lowered.

  Patent Document 2 proposes a method for combining and registering feature point data extracted from a fingerprint image. In this method, the validity of the synthesized feature point data is verified based on the distribution state of the feature points, thereby improving collation accuracy.

  However, in Japanese Patent Laid-Open No. 2004-260688, synthesis is performed in consideration of the suitability of each feature point data as a registered fingerprint obtained from a plurality of feature point data and the finger placement characteristics (eg, the direction of finger placement) unique to the user. Not done. Therefore, the obtained registered fingerprint is not necessarily suitable for authentication, and high collation accuracy cannot be obtained stably.

  The present invention has been made in order to solve the above-described problem. A biometric authentication apparatus for synthesizing and registering feature point data suitable for authentication by a technique suitable for authentication when synthesizing feature point data is provided. It is intended to provide.

  In view of the above-described object, an object of the present invention is to input biometric information input means for inputting a biometric information image in a biometric information authentication apparatus that performs personal authentication of a user by collating registered biometric information with input biometric information. In order to generate a biometric feature composed of feature point information from the biometric information image, a feature extracting unit that extracts a plurality of feature points, a storage unit that stores a plurality of biometric information features, and the plurality of biometric features Similarity determination means for determining similarity by collating information features and determining whether or not they are similar to each other, and when the similarity determination means determines that they are similar, the stored biological information features are combined to generate combined biological information It is an object of the present invention to provide a biometric information authentication apparatus comprising: a feature synthesis unit that generates a feature; and a feature registration unit that sets the synthesized biometric information feature in registered biometric information.

  According to the present invention, registered biometric information with high matching accuracy at the time of authentication can be obtained by determining and synthesizing each biometric information feature with suitability as reflected in the registered biometric information. Also, by registering features based on one reference biometric information feature that stably corresponds to the positional deviation of a plurality of biometric information placements, registered biometric information that reflects the biometric information placement characteristics (癖) of the user is obtained. be able to. In addition, the feature reproduction information can be used effectively, and a feature effective for biometric information authentication can be selectively picked up from a plurality of biometric features and synthesized.

  The present invention can be applied to various biological information. Other than fingerprints, for example, blood vessel patterns (finger, back of hand, palm, retina, etc.), palm prints, ear shapes, and the like have end points and branch points as in the case of fingerprints, and therefore the synthesis processing of the present invention can be applied. Therefore, even in an authentication apparatus using such biometric information, registered biometric information that reflects the habit of each registrant's biometric information input can be generated, and highly accurate authentication can be realized.

Hereinafter, an example will be described by taking a fingerprint as an example of biometric information.
FIG. 1 is a diagram showing the overall configuration of the present invention. Each part of FIG. 1 will be schematically described.

  The operation / display unit 100 performs input of an ID number of a registrant, a personal identification number of a device manager, an operation state, and guidance. The operation / display unit 100 includes a touch panel display and a speaker. A numeric keypad and a liquid crystal display may be used instead of the touch panel display.

  The fingerprint input unit 110 outputs a digital image of the fingerprint when the operator presses the finger. The fingerprint input unit 110 typically includes an LED that illuminates a finger, an optical fingerprint sensor that modularizes a CCD camera that captures a finger and converts it into a digital signal, and a user to correctly recognize the finger placement position. The finger guide member. There are various other principles such as capacitance type and pressure type in the fingerprint sensor, but the present invention does not limit the principle of the fingerprint sensor.

  The storage unit 120 is configured by a memory device such as a flash memory, and stores a feature point list that is biometric information features to be described later, a synthetic feature point list that is synthetic biometric information features as registered data, and the like.

The processing unit 130 is configured by a CPU or the like that can input and output digital signals and store and execute a program for processing the digital signals.
The control unit 140, feature extraction unit 150, feature synthesis unit 160, feature registration unit 170, and authentication unit 180 described below are included in the processing unit 130 and realized by the program.

  The control unit 140 controls the operation of the operation / display unit 100, the fingerprint input unit 110, and the storage unit 120, the processing flow by the feature extraction unit 150, the feature synthesis unit 160, and the feature registration unit 170. Specific operations will be described later.

The feature extraction unit 150 processes a digital image of a fingerprint and extracts feature points. Here, the feature points mean the end points of the fingerprint ridges and the branch points that are the ridges.
FIG. 2 is a diagram illustrating an example of position coordinates and directions of fingerprint feature points. In the figure, 200, 210, and 220 are end points, and 230 is a branch point, respectively.

The feature point has data elements of position (x, y), declination (hereinafter referred to as direction parameter) θ corresponding to the direction, and reliability W as individual information.
The position (x _T , y _T ) of the end point 200 is illustrated in FIG. 2A, and the direction parameter θ _T of the end point 200 is illustrated in FIG. 2B.

The direction of the feature point is the direction in which the neighboring ridges flow. If the point is a branch point, the direction is a branch destination direction. The direction parameter θ is set clockwise from the x-axis direction.
The reliability W of the feature point is obtained as a value proportional to the magnitude of the direction vector obtained by adding the respective direction unit vectors of neighboring feature points including the feature point. This is a value reflecting the degree of consistency between the feature points and the neighboring feature points, and takes a maximum value when the neighboring feature point directions including the feature points are all in the same direction. The reliability W is an index representing the reliability of the direction of each feature point and the reliability of existence, and the calculation method is not limited to this.
A plurality of feature points (x _i , y _i , θ _i , W _i ) are extracted from one fingerprint image, and these are output as a feature point list.

The feature synthesizer 160 reads a plurality of feature point lists from the storage unit 120, associates them with each other, aligns them, and makes one feature point list therefrom (hereinafter referred to as a synthesized feature point list). Is generated.
FIG. 3 is a diagram illustrating an example of a plurality of feature point lists obtained from a plurality of finger placements. FIG. 4 is a diagram illustrating an example of association and alignment of feature points. FIG. 5 is a diagram illustrating an example of a feature point synthesis result. An outline of the synthesis will be described with reference to FIGS.

  FIG. 3 shows a plurality (three in this case) of feature point lists A, B, and C. In the figure, the center of gravity of each triangle represents a feature point, and the direction from the center of gravity of the triangle toward the point corresponding to the minimum apex angle represents the direction of the feature point. The rectangular frame is a fingerprint sensor area.

FIG. 4 shows the result of matching and alignment of these feature point lists. In association, one reference list is defined, and each feature point of another feature point list is associated with it.
In FIG. 4, the feature point list A is a reference list, and the feature points of the feature point lists B and C are associated with it. For this purpose, alignment is performed by superimposing feature points that have been matched.

FIG. 5 is a feature point list synthesized from the alignment result.
The combined feature point list is a list in which feature points that can be matched and feature points that cannot be matched (hereinafter referred to as isolated feature points) are mixed according to a predetermined rule.
Details of the processing of the feature synthesis unit 160 will be described later.

  The feature registration unit 170 stores the combined feature point list and the registrant ID number in the storage unit 120 in association with each other.

  The authentication unit 180 is a feature point list (hereinafter referred to as an input feature point list) obtained by processing the fingerprint image of the person to be authenticated (person who is going to receive authentication) input from the fingerprint input unit 110 at the time of authentication by the feature extraction unit 150. ) And a registered composite feature point list (hereinafter referred to as a composite feature point list) read out from the storage unit 120 to calculate a similarity, and compares this with a verification threshold value to obtain a registrant. Judge whether to give the authentication.

  FIG. 6 is a flowchart of processing for registering a fingerprint feature point list. Hereinafter, the operation of the biometric information authentication apparatus according to the present invention will be described with reference to FIG. Note that the description will be made assuming that the number of times of fingerprint input necessary for registration is three.

When the device administrator operates the touch panel display of the operation / display unit 100 to select a registration menu and inputs a personal identification number, the device manager enters the registration mode and starts the registration process (S600).
The user who intends to register operates the operation / display unit 100 to input an ID number that can identify the user, such as an employee number, in accordance with a guidance such as “Please input ID number” (S605).

The user who wants to register places his / her finger on the fingerprint sensor, which is the fingerprint input unit 110, in accordance with a guidance such as “Please put your finger” (S610).
A digital signal of a fingerprint image is output from the fingerprint sensor and input to the processing unit 130.
The control unit 140 activates the feature extraction unit 150 and inputs a fingerprint image to the feature extraction unit 150.

The feature extraction unit 150 calculates feature point parameters (x _i , y _i , θ _i , W _i ) from the fingerprint image, and lists a set of feature point lists ((x _i , y _i , θ _i , W _i )). ) Is generated (S615).
Further, the feature extraction unit 150 checks whether the generated feature point list satisfies a predetermined condition. That is, it is checked whether the total reliability of the feature points included in the feature point list is equal to or greater than a predetermined value (S620).

(A) If the total reliability of the feature points included in the feature point list is greater than or equal to a predetermined value as a result of the inspection, the feature extraction unit 150 determines that the feature point list is valid and stores the list in the storage unit 120, and notifies the control unit 140 that a predetermined condition has been satisfied (S625).
(A) If the total reliability of the feature points included in the feature point list is less than a predetermined value as a result of the inspection, the feature extraction unit 150 determines that the feature point list is not valid and stores it in the storage unit 120. And notifying the control unit 140 that the predetermined condition is not satisfied.

The control unit 140 performs control according to the notification from the feature extraction unit 150.
(A) If the notification indicates that the predetermined condition is satisfied, the control unit 140 increments the counter for counting the number of fingerprint inputs by 1 (S630), and performs the following control.
When the number of fingerprint inputs reaches 3, the control unit 140 activates the feature synthesis unit 160 (to S640).
When the number of fingerprint inputs is less than 3, the control unit 140 displays guidance for prompting the next fingerprint input on the operation / display unit 100 (to S610).
(A) If the notification indicates that the predetermined condition has not been satisfied, the control unit 140 displays guidance for prompting re-input of the fingerprint on the operation / display unit 100 (to S610).

The feature synthesis unit 160 reads out the three feature point lists from the storage unit 120, and generates a synthesized feature point list by synthesizing them (S640). Details of the synthesis process will be described later.
The feature synthesis unit 160 further determines the success or failure of the synthesis process (S645).
When the synthesis process is successful, the feature synthesis unit 160 notifies the control unit 140 of the success.
When the synthesis process fails, the feature synthesis unit 160 notifies the control unit 140 of the failure.

The control unit 140 performs control according to the notification from the feature synthesis unit 160.
If the notification is successful, the control unit 140 activates the feature registration unit 170, and the feature registration unit 170 sets registration data by associating the ID number with the composite feature point list stored in the storage unit 120. (S650). Then, the control unit 140 displays a guidance such as “registration is completed” on the operation / display unit 100 (S655).
If the notification is a failure, the control unit 140 displays a guidance such as “registration failed” on the operation / display unit 100 (S655).

  FIG. 7 is a flowchart of processing for combining a plurality of feature point lists. An example of the feature point synthesis process (S640) will be described with reference to FIG.

First, the feature synthesizer 160 selects a reference list as a reference for synthesis from the obtained three feature point lists (S775). A feature point list having the highest overall similarity calculated by collating with other feature point lists is selected as the reference list. Here, as an example of the selection criterion, three indicators are used: the number of NGs obtained from the similarity, the minimum similarity, and the total similarity.
FIG. 8 is a diagram illustrating an example of how a reference list is selected from a plurality of feature point lists.
First, mutual matching is performed for all combinations (in this example, six) of the three feature point lists used for synthesis, and the similarity is calculated (S700). The similarity S is calculated by the following formula.

  Here, Wi represents the reliability of the i-th feature point in one feature point list, and Ci represents the association result (with pair: 1, without pair: 0) with the other feature point list. Note that the method of calculating the similarity S is not limited to this, and various expressions such as taking into account the reliability of the other feature point list can be considered.

Here, the number of NG times which is the first index for selecting the reference list is obtained (S705). The similarity S obtained in S700 as compared with the predetermined threshold value T _s, counted as NG attempts is smaller than the threshold value. The number of NG times is counted for each feature point list. In the example of FIG. 8, T _s = 0.65 is set, and the NG counts from A to C are 0, 2, and 0, respectively.

NG attempts is a candidate for a reference list feature point list below a predetermined value T _NG (S710). In the example of FIG. 8, T _NG = 0 is set, B is excluded from the candidates, and A and C remain as candidates. If no candidate remains, the feature synthesis unit 160 aborts the process and notifies the control unit 140 of synthesis failure.

  The reference list candidate having the smallest number of NG times is determined as a reference list (S715). If one can be selected, the process proceeds to S735, and if one cannot be selected, they are left as reference list candidates and the process proceeds to S720. In the example of FIG. 8, since the number of NGs of A and C is both 0, both remain as candidates.

Next, as the second index of the reference list, the minimum value of the similarity obtained in S700 is obtained for each reference list candidate (S720).
Among the reference list candidates, the feature point list having the largest similarity is determined as the reference list (S725). By doing so, the reliability of synthesis can be kept higher. If one can be selected in the determination here, the process proceeds to S735. If one cannot be selected, these are left as candidates and the process proceeds to S730. In the example of FIG. 8, since the similarity minimum values of A and C are both 0.7, the reference list is not determined at this point.

  Furthermore, as a third index for selecting a reference list, a total value of similarities is obtained for each reference list candidate, and a reference list candidate having the largest similarity total value is determined as a reference list (S730). In the example of FIG. 8, since the similarity total value of A is larger than the similarity total value of C, it is determined that A is used as the reference list.

  As described above, similarity is obtained for each combination of a plurality of feature point lists used for composition, and feature point data is synthesized only when there is a feature point list having a high degree of similarity with another feature point list. Do. In other words, when a certain degree of similarity cannot be obtained when a certain feature point list is collated with another feature point list, there is a possibility that any feature point list is not the same fingerprint, Such a feature point list should not be used for synthesis. Therefore, if the above conditions are not met, the synthesis process can be stopped to obtain synthesized feature point data with high reliability.

Note that the similarity threshold Ts used here is equal to or slightly lower than the similarity threshold used when the input feature point list and the registered feature point list are collated in the later-described authentication process. desirable. By setting the threshold value Ts to a value close to the threshold value used for authentication, only fingerprints with extremely high identity are used for synthesis, and highly reliable synthesized feature point data can be obtained.
The selected reference list has many corresponding feature points with other feature point lists, and has the highest similarity with the other feature point lists. Therefore, by performing the synthesis process based on the selected feature point list, a synthesized feature point list that strongly represents the uniqueness of the input fingerprint can be obtained. The composite feature point list obtained in this way flexibly supports the characteristics of the user's finger placement (eg, the orientation of the finger), so that the degree of similarity between the list and the legitimate input fingerprint is sufficient for authentication. This increases the collation accuracy.

  Generating a composite feature point list through the above conditions is different from simply expanding the fingerprint area, and it is synthesized by complementing the shift of the feature point data area caused by the shift of the finger placement position. It becomes.

  Here, an example of processing for selecting a reference list by calculating similarity and three indexes for all combinations of feature point lists has been shown, but the processing of S700 to S730 is a loop processing for the feature point list, and the similarity is calculated. It is also possible to omit unnecessary calculations (acceleration) by sequentially making a determination based on each index each time.

For example, in FIG. 8, the loop processing is executed in the order of processing relating to A in the first row of the table, processing relating to B in the second row, and processing relating to C in the third row. At this time, if the similarity 0.6 of A to B is obtained in the process of B relating to the second row, this is less than T _s , so the number of _NG exceeds T _NG and B is not a reference list candidate. It is fixed. Therefore, the calculation of the similarity C of 0.5 to B can be omitted.

When the reference list is selected in the selection of the reference list (S775), the process proceeds to a specific process of synthesis. First, the grouping of feature points in the reference list is initialized (S735).
As initialization of this processing, each feature point of the reference list is configured as an independent group, and each feature point is set to be a reference feature point in each group.
Here, the reference feature point is a feature point to be compared to determine whether another feature point belongs to the group.

  A feature point list to be aligned with the reference list is selected (S740).

Next, the selected feature point list is converted into a coordinate system of reference data, and feature point alignment is performed (S745).
Here, first, the coordinates of the center of gravity and the rotation angle for performing superposition so that the centers of gravity coincide with each other are calculated using the parameters of the feature points that can be matched between the reference list and the feature point list. To do. Then, using these parameters, alignment by affine transformation (Image Analysis Handbook, University of Tokyo Press) is performed.

The affine transformation is a transformation that moves and rotates in the vector space, and the coordinate system of the feature point list is transformed into the coordinates of the reference list.
FIGS. 9A to 9C are diagrams showing examples of alignment of fingerprints by affine transformation. The figure shows a state where (c) is obtained as a result of aligning the fingerprint B (feature point list B (b)) with the fingerprint A (reference list A (a)) by affine transformation. At this time, the greater the number of feature points that can be handled, the higher the accuracy of alignment.

  In the reference list selection processing, the feature point list having the highest stability is selected as the reference list, so that the alignment accuracy can be increased. This can effectively increase the authentication accuracy at the time of fingerprint collation.

  Following the alignment process, feature points that can be regarded as identical across a plurality of feature point lists are grouped (S750).

Here, the reference feature point in each existing group is compared with the position coordinates after alignment of each feature point in the feature point list currently being processed, and the distance from the nearest reference feature point is obtained.
If the distance is greater than a predetermined threshold, it is determined that the feature point does not correspond to the reference feature point, a new group is created, and registered as a reference feature point of the group.

If the distance is within a predetermined threshold, evaluate the direction difference between the feature point and the reference feature point, and if this is greater than the predetermined threshold, determine that both feature points do not correspond to create a new group, The feature point is registered as the reference feature point of the group.
If the direction difference is within a predetermined threshold, it is determined that the feature point and the reference feature point are the same corresponding feature point, and the feature point is additionally registered in the group to which the reference feature point belongs.

When a feature point is added to an existing group, the feature point having the highest reliability is obtained in the group, and the feature point is changed to be a reference feature point in the group from the next grouping.
FIG. 10 is a diagram illustrating an example of grouping of feature points. FIG. 4 shows how feature points list A (reference list), B, and C are associated with each other and an example of grouping.

  Next, it is determined whether or not the processing of S740 to S750 has been completed for all feature point lists (S755). If processing has not been performed for all lists, the process returns to feature point list selection (S740). If processing for all lists has been completed, the process proceeds to corresponding feature point averaging (S760).

The feature point information of each feature point group is averaged (S760). A set of feature points subjected to the averaging process is called a composite feature point list. Here, a group having two or more feature points such as 1000 in FIG.
The averaging process is performed by weighting the feature point position coordinates and direction parameters with the reliability of each feature point as a weight, and the reliability is arithmetically averaged. One piece of feature point information is obtained for each group. To. Thereby, the parameter information of the feature point with high reliability is largely reflected.

  In this embodiment, the group is made one feature point by the averaging process, but the feature point having the highest reliability in the group can be represented. Preferably, information on a plurality of feature points is reflected by averaging.

Since groups with two or more feature points are considered to contain highly reliable feature points with high reproducibility of feature points, the averaged feature points are added to the combined feature point list. Selected as.
Note that if the reproducibility conditions are stricter (for example, grouping is performed for the first time with three or more feature points), highly reliable feature points can be selected more carefully. In that case, a group of reproducible feature points below this can be processed in the same manner as an isolated feature point described later after averaging processing.
FIG. 11 is a diagram illustrating an example of feature point averaging, and shows feature points averaged based on the grouping of FIG. 10.

  Subsequently, when there is only one feature point in the group as in 1001 in FIG. 10, whether or not to add the feature point (isolated feature point) to the combined feature point list as follows is selected (S765). ).

FIG. 12 is a diagram illustrating an example of selection of isolated feature points.
In the synthesized feature point list, a convex hull region 1200 of a feature point group having a number of associations of 2 or more is set by associating the reference list with another feature point list as shown in FIG. Then, it is determined whether or not each isolated feature point is included in the convex hull region, and the isolated feature point is added to the combined feature point list only when it is not included.

This area is an area that has been input twice or more by the fingerprint input of the registrant. Nevertheless, when the isolated feature point is included in the area, the isolated feature point is extracted only once even though there is a plurality of extraction chances, so that the reproducibility is low. Judge as a feature point and do not add to the combined feature point list.
For isolated feature points that exist outside the convex hull region, feature points extracted from a region in which the isolated feature point is covered only by one feature point list (for example, a region that has been imaged only once due to misalignment, etc.) However, although reproducibility cannot be evaluated, it is considered to be a feature point with high utility value in order to cope with a positional shift at the time of collation. Therefore, this is added to the composite feature point list.

  FIG. 12 illustrates a sample of isolated feature points that should be added to the list and isolated feature points that should not be added. In this figure, it was determined not to add two isolated feature points.

  When the selection of the isolated feature points is finished in S765, the information of the feature points averaged in S760 and the information of the selected isolated feature points are selected in the synthesized feature point list, and the synthesized feature point list is determined ( S770).

  Here, the distance is calculated to check whether all feature points in the composite feature point list are too close to other feature points. The lower feature point may be excluded from the list. This is because at least one of the feature points that are too close is highly likely to be a pseudo feature point caused by finger drying or rough hands.

  Alternatively, the composite feature point list may be sorted in the order of reliability, and a predetermined number of feature points may be selected from the top of the list.

  In the feature synthesis process (S640), when performing registration of a certain feature point list, the feature point that is currently being registered from a feature point list that has already been registered, instead of a fixed reference list. A list of registered feature points that provides the best alignment accuracy (the highest mutual similarity) may be selected each time as a reference list, and a combined feature point may be created by aligning the selected list. .

Further, in the feature synthesis process (S640), a temporary composite feature point list may be created every time alignment is performed, and this list may be used as a reference list for the next alignment.
Further, in the feature point synthesis process (S640), the reliability of the feature points outside the convex hull region (for example, 1200 in FIG. 12) of the corresponding feature points in the reference feature point list and the other feature point list is lowered. Also good.

Also, in the corresponding feature point averaging (S760), only when the reliability of the feature point is a predetermined value or more, the corresponding feature point may be reflected in the averaging.
In addition, in the isolated feature point selection (S765), only isolated feature points having reliability of a predetermined value or more can be added and synthesized, and separately, no isolated feature points can be added.

  In the composite feature point list, a convex hull region of a feature point group having a number of associations of 2 or more is set by matching the reference list with another feature point list. This setting region includes at least the feature point. Any area may be used as long as it includes all. For example, an isolated feature point may be selected using an area corresponding to a reference list as the setting area. As another example, a convex hull region obtained from all feature points in another feature point list (for example, A and C) is set and selected for an isolated feature point in a certain feature point list (for example, B). it can. The same applies to the case of lowering the reliability of feature points outside the setting area.

  FIG. 13 is a flowchart of processing for authenticating a fingerprint.

The touch panel display of the operation / display unit 100 is operated by the person to be authenticated (those who want to receive authentication), and the ID number is input (S1300).
A finger is placed on a fingerprint sensor constituting the fingerprint input unit 110 in accordance with a guideline such as “Please input a fingerprint” by the person to be authenticated.

A digital signal of a fingerprint image is output from the fingerprint input unit 110 and input to the processing unit 130 (S1305).
The control unit 140 activates the feature extraction unit 150 and inputs a fingerprint image to the feature extraction unit 150.
The feature extraction unit 150 extracts a plurality of feature points from the fingerprint image, and generates an input feature point list based on the information of each feature point (S1310).

The control unit 140 activates the authentication unit 180 and inputs an input feature point list to the authentication unit 180.
The authentication unit 180 reads a combined feature point list (hereinafter referred to as a registered feature point list) registered in association with the ID number input from the storage unit 120 (S1315).
The registered feature point list and the input feature point list are collated to calculate the similarity (S1320).

  The similarity is compared with the collation threshold, and if the similarity is equal to or greater than the collation threshold, a determination is made that authentication is given to the person to be authenticated, and if not, a determination is made that authentication is not given (S1325).

  In the above description, an embodiment of an authentication device using a fingerprint as biometric information for identifying an individual has been described. However, the present invention can also be applied to biometric information other than fingerprints. For example, blood vessel patterns (finger, back of hand, palm, retina, etc.), palm print, ear shape, and the like have end points and branch points as shown in FIG. Therefore, even in an authentication apparatus using such biometric information, registered biometric information that reflects the habit of each registrant's biometric information input can be generated, and highly accurate authentication can be realized.

It is a figure showing the whole structure of this invention. It is a figure showing the example of the position coordinate and direction of the feature point of biometric information, such as a fingerprint. It is a figure which shows the example of the several feature point list | wrist obtained from the multiple times of finger placement. It is a figure which shows the example of matching of a feature point, and position alignment. It is a figure which shows the example of the synthetic | combination result of a feature point. It is a flowchart of the process which registers the feature point list | wrist of a fingerprint. It is a flowchart of the process which synthesize | combines several feature point lists. It is a figure which shows the example of a mode that a reference | standard list is selected from several feature point list | wrists. It is a figure which shows the example of the alignment of the fingerprints by an affine transformation. It is a figure which shows the example of grouping of the feature point. It is a figure which shows the example of averaging of a feature point. It is a figure which shows the example of selection selection of an isolated feature point. It is a flowchart of the process which authenticates a fingerprint.

Explanation of symbols

100 Operation / Display Unit 110 Fingerprint Input Unit 120 Storage Unit 130 Processing Unit 140 Control Unit 150 Feature Extraction Unit 160 Feature Synthesis Unit 170 Feature Registration Unit 180 Authentication Unit

Claims (2)

In a biometric information authentication device that performs personal authentication of a user by comparing registered biometric information and input biometric information,
Biometric information input means for inputting a biometric information image;
Feature extraction means for extracting a plurality of feature points in order to generate a biometric feature composed of feature point information from the input biometric information image;
Storage means for storing a plurality of biological information features;
An associating means for associating the feature points among the plurality of biometric information features , and dividing the plurality of feature points into corresponding feature points that can be matched and isolated feature points that cannot be matched;
A synthetic biometric information feature that includes a convex hull region that includes at least all of the corresponding feature points, and includes the corresponding feature points and the isolated feature points outside the convex hull region, excluding the isolated feature points in the convex hull region. A feature synthesis means for generating
Feature registration means for setting the synthetic biometric information feature in registered biometric information;
A biometric information authentication device comprising: The feature point information further includes the reliability of each feature point,
The biometric information authentication apparatus according to claim 1 , wherein the feature synthesizing unit generates the synthetic biometric information feature by reducing the reliability of the isolated feature point outside the convex hull region .

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