JP4477258B2 - Fingerprint verification device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fingerprint collation apparatus, a fingerprint registration method and a fingerprint collation method used therefor, and more particularly to improvement of collation accuracy.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a fingerprint collation device that images a fingerprint with an optical or capacitive fingerprint reading sensor and collates it with a pre-registered fingerprint. Incidentally, an optical type such as a CCD (Charge Coupled Device) image sensor is often used for the fingerprint reading sensor.
[0003]
When a fingerprint image is captured, the finger is pressed against the input unit, and the fingerprint in the contact area of the finger that is in contact with the input unit is imaged by the sensor. Conventionally, a fingerprint image is captured when the contact area reaches a predetermined size. Correspondingly, a fingerprint image registered in advance is also stored having a predetermined size.
[0004]
[Problems to be solved by the invention]
The conventional method and configuration in which the input fingerprint captured at the time of collation and the pre-registered registered fingerprint to be collated with the fingerprint image of a predetermined size are suitable for collation because there are individual differences in finger sizes. Input fingerprint / registered fingerprint could not be obtained. For example, the finger pressing on the input unit when the fingerprint image has a predetermined size is generally small for a person with a large finger and large for a person with a small finger. For this reason, the fingerprint image may be a fingerprint image in which the ridge (convex part) of the fingerprint is crushed due to a strong press, or a fingerprint image in which the ridge is faint due to a weak press. There was a problem that could not be obtained.
[0005]
On the other hand, when the fingerprint is read and configured when the finger pressure reaches a predetermined value, input fingerprints and registered fingerprints suitable for collation can be obtained due to individual differences in skin softness. There may not be. For example, when a fingerprint is read with a constant pressure, if the person has a hard skin, the area of the finger that touches the input area may be small, and only a part of the finger may be read. However, the ridges are crushed, and there still arises a problem that sufficient accuracy of matching cannot be obtained with these fingerprint images.
[0006]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fingerprint collation apparatus that reduces the influence of individual differences and improves collation accuracy, and a fingerprint registration method and fingerprint collation method used therefor. .
[0007]
[Means for Solving the Problems]
The fingerprint collation apparatus according to the present invention is a fingerprint collation apparatus that reads an input fingerprint from a finger pressed against a fingerprint reading sensor and collates the input fingerprint with a registered fingerprint registered in advance. A pressure switch that is turned on when the pressure of the pressure exceeds a predetermined value, and a registration processing unit that determines and registers the registered fingerprint of the registered person based on the input fingerprint of the registered person, and the registration The processing unit includes a registered person fingerprint sampling unit that reads the input fingerprint by the fingerprint reading sensor at a reading timing delayed by a predetermined time from the time when the pressure switch is turned on.
[0008]
According to the present invention, the pressure switch is turned on with a constant press for different registered persons, but the collection of registered fingerprints is not the timing when the pressure switch is turned on, but is delayed for a relatively short predetermined time thereafter. It is done at the timing. A registered person is a person whose fingerprint is registered in advance in the apparatus, and is usually a user who is given authentication by fingerprint verification. The set value of the pressure at which the pressure switch is turned on is set to a level in the middle of the finger pressing against the fingerprint reading sensor. It has increased. The pressing at that time generally differs depending on the registered person. Only one input fingerprint may be collected, but a plurality of input fingerprints may be collected by reading at a plurality of delayed predetermined reading timings. When a plurality of input fingerprints are collected for the same registered person, for example, any suitable fingerprint may be selected.
[0009]
In another fingerprint collation device according to the present invention, the registration processing unit acquires a plurality of the input fingerprints for any of the registered persons by changing the reading timing.
[0010]
According to the present invention, an input fingerprint is read for each registered person at a plurality of timings with different elapsed times after the pressure switch is turned on, and registration is performed based on the plurality of input fingerprints. A fingerprint is defined and registered.
[0011]
A preferred aspect of the present invention is a fingerprint collation apparatus in which the registration processing unit uses the registered person fingerprint sampling unit a plurality of times while changing the reading timing for an arbitrary registered person. In this aspect, the registered person presses the finger against the fingerprint reading sensor a plurality of times, and the registered person fingerprint sampling means is activated a plurality of times. The registered person fingerprint sampling means reads the input fingerprint at different reading timings every time the same registered person is continuously activated, and collects a plurality of input fingerprints at different timings.
[0012]
Another preferred aspect of the present invention is a fingerprint collation device in which the registered person fingerprint sampling unit reads the input fingerprint at a plurality of reading timings when the pressure switch is turned on. In this aspect, when the registered person presses the finger once on the fingerprint reading sensor and the registered person fingerprint sampling means is activated, the registered person fingerprint sampling means is not activated until the pressure switch is turned on. The input fingerprint is read at a plurality of predetermined timings with different elapsed times, and a plurality of input fingerprints are collected.
[0013]
In yet another fingerprint collation device according to the present invention, the registration processing unit selects, as the registered fingerprint, a plurality of input fingerprints obtained for the arbitrary registered person and suitable for the collation. Selecting means; and registration means for registering the registered fingerprint and the reading timing corresponding to the registered fingerprint in association with the registered person.
[0014]
According to the present invention, among a plurality of input fingerprints collected, one that is suitable for collation is selected in principle and used as a registered fingerprint. Whether or not it is suitable for collation can be determined based on the size of the collected fingerprint, whether the contrast of the fingerprint image is clear, or there is no missing portion, and the like. The registered fingerprint is stored in association with the registered person, and in the present invention, the reading timing when the input fingerprint as the registered fingerprint is collected, that is, the elapsed time since the pressure switch is turned on is also associated with the registered person. Is remembered.
[0015]
In another fingerprint collation device according to the present invention, when the pressure switch is turned on by a person to be collated with the person to be registered, at the reading timing registered for the person to be registered, A verification target fingerprint sampling means for reading the input fingerprint of the verification target is provided.
[0016]
According to the present invention, when determining whether or not a person to be verified is a registered person based on fingerprint verification, the input fingerprint of the person to be verified is read timing registered for the registered person. Are read at the same timing. That is, the time from when the pressure switch is turned on for the person to be verified is the time from when the pressure switch for the person to be registered is turned on to when the input fingerprint, which is a registered fingerprint, is collected. The input fingerprint from the person to be verified is read. Thus, if the person to be collated is a registered person to be collated, the accuracy of collating both is improved in that the input fingerprint collecting condition is the same as that of the registered fingerprint. The registered fingerprint is selected as a suitable collation from a plurality of input fingerprints, and the input fingerprint collected at the same timing as this registered fingerprint is, for example, clear, etc. It is expected to be suitable for verification. Therefore, also in this respect, accuracy can be improved when these input fingerprints and registered fingerprints are collated.
[0017]
The fingerprint registration method according to the present invention includes a fingerprint reading step of reading the input fingerprint at a plurality of reading timings after the finger press on the fingerprint reading sensor exceeds a predetermined value, and an arbitrary fingerprint reading step A selection step of selecting, as the registered fingerprint, the one suitable for the fingerprint collation among the plurality of input fingerprints obtained for the registered person of the registered person, and the reading timing corresponding to the registered fingerprint and the registered fingerprint And a registration step of registering in association with the registered person.
[0018]
The fingerprint collation method according to the present invention includes a registration processing step of determining and registering the registered fingerprint based on the input fingerprint of the registered person, and the input fingerprint of the verified person and the registered fingerprint of the registered person A collation processing step for performing collation, and the registration processing step includes the step of reading the input fingerprints at a plurality of read timings after a pressure of the registered person's finger against the fingerprint reading sensor exceeds a predetermined value. A registered person fingerprint reading step to be read, and a selection for selecting, as the registered fingerprint, a plurality of the input fingerprints obtained for any of the registered persons in the registered person fingerprint reading step that is suitable for the collation And a registration step of registering the registered fingerprint and the reading timing corresponding to the registered fingerprint in association with the registered person, The collation processing step includes the input of the person to be collated at the reading timing registered with respect to the person to be registered after the finger pressing of the person to be collated with respect to the fingerprint reading sensor becomes equal to or greater than the predetermined value. A verification target fingerprint reading step for reading the fingerprint;
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0020]
FIG. 1 is a schematic block diagram of a fingerprint collation apparatus according to the present invention. This apparatus includes a main body module 2 and an operation module 4. The operation module 4 is installed in a place that requires authentication by fingerprint verification. For example, the operation module 4 is installed near the entrance to an area where security is maintained, and a person who intends to enter the area presents his / her finger to the operation module 4 and is authenticated by fingerprint verification. The collation result in the operation module 4 is transmitted to the main body module 2. The main body module 2 stores the fingerprint information (registered fingerprint) of the user who gives authentication, and controls the opening and closing of the electric lock at the entrance, for example. The main body module 2 is configured separately from the operation module 4 to prevent leakage of registered fingerprints, and is installed in a place where security is maintained.
[0021]
The main body module 2 includes a storage unit 10 and a control unit 12. For example, information of a registered user (registered person) is stored in the storage unit 10. The registered user information includes, for example, an identification number (ID number), a registered fingerprint, and additional information described later. Based on the collation result from the operation module 4, the control part 12 performs opening / closing of an electric lock, an alarm generation, etc., for example.
[0022]
The operation module 4 includes a fingerprint input unit 20, a processing unit 22, an operation unit 24, and a display unit 26.
[0023]
The fingerprint input unit 20 includes a fingerprint reading sensor 30 and a pressure switch 32. FIG. 2 is a schematic cross-sectional view of the fingerprint input unit. In this apparatus, the fingerprint reading sensor 30 optically reads a fingerprint. Specifically, light from a light source 44 such as an LED (Light Emission Diode) is irradiated through a prism lens 46 toward a finger placement unit 40 formed of a transparent glass plate or the like. The finger 42 is pressed against the surface of the finger placement unit 40, and the fingerprint of the contact portion appears. The fingerprint is photographed by an image sensor 48 such as a CCD (Charge Coupled Device) image sensor. The finger placement unit 40, the light source 44, the prism lens 46, and the imaging device 48 constitute the fingerprint reading sensor 30.
[0024]
The pressure switch 32 is turned on when the pressure applied to the pressure-sensitive unit 50 disposed below the finger placement unit 40 becomes a predetermined value or more. The pressure switch 32 may have a function of the switch itself. In addition, for example, the pressure sensor 50 is a pressure sensor, and on / off is controlled according to the pressure sensor and its output. The pressure switch 32 can also be configured by a control circuit that performs the above. The pressure switch 32 is for starting a fingerprint reading operation by the fingerprint reading sensor 30 when a finger is pressed against the finger placement unit 40.
[0025]
The processing unit 22 includes a verification processing unit 60 and a registration processing unit 62. The processing unit 22 is basically composed of a central processing unit (CPU), and the verification processing unit 60 and the registration processing unit 62 are software executed by the CPU. Each processing content will be described later.
[0026]
The operation unit 24 is an input unit for inputting a user ID number, performing an operation switching instruction at the time of fingerprint registration, and the like. The display unit 26 is an output unit that displays an input ID number, an operation state of the apparatus, operation guidance, an error message, and the like. In the present apparatus, the operation unit 24 and the display unit 26 are integrally configured by an LCD (Liquid Crystal Display) with a touch panel.
[0027]
Next, operations and processing at the time of fingerprint registration in this apparatus will be described. FIG. 3 is a processing flow diagram at the time of fingerprint registration. When newly registering a user to be authenticated by this apparatus, or when updating information of a registered user, the registration processing unit 62 is activated and the registered user information of the user is newly recorded in the storage unit 10. To do. Usually, since the verification processing by the verification processing unit 60 is executed in the processing unit 22, in order to perform the registration processing, an operation for starting the registration processing unit 62 and switching the processing from the verification processing to the registration processing is performed from the operation unit 24. Separately (S100).
[0028]
When the registration processing unit 62 is activated, the ID number assigned to the registered person is input from the operation unit 24 by the registered person himself or another operator (S105). The registration processing unit 62 initializes the fingerprint reading count k to 1 (S110). Next, the registered person presses his / her finger against the finger placement unit 40 of the fingerprint input unit 20, and the apparatus reads the fingerprint of the registered person by the fingerprint reading sensor 30.
[0029]
This reading operation is started when the pressure of the finger pressed by the registered person against the fingerprint reading sensor 30 becomes equal to or greater than a predetermined value set in the pressure switch 32, and is repeated a predetermined number of times (for example, four times here). It is. When the pressure exceeds a predetermined value, the pressure switch 32 is turned on (S115), and the registration processing unit 62 counts an elapsed time from the time when the pressure is turned on. When the elapsed time reaches the predetermined time T _k , the registration processing unit 62 drives the fingerprint reading sensor 30 to capture the fingerprint image P _k at the timing T _k (S120). Here, the timing T _k is set to be different depending on the value of k, that is, for each reading operation. In addition, since the reading timing T _k is different, the fingerprint image P _k may be different every time. For example, T ₁ , T ₂ , T ₃ , and T ₄ can be 0 milliseconds, 100 milliseconds, 200 milliseconds, and 300 milliseconds, respectively. These T _k are set, for example, within a transition period in which the finger pressure is increasing, whereby a plurality of fingerprint images having different degrees of adhesion to the finger placement unit 40 are obtained.
[0030]
When the fingerprint image P _k is obtained, the registration processing unit 62 calculates an evaluation value V _k indicating the degree to which the fingerprint image is suitable for collation (S125). As this evaluation value, for example, the contrast sharpness of a fingerprint image can be used. The sharpness of contrast can be determined based on, for example, a fluctuation pattern of image data on a certain straight line in a fingerprint image. For example, a large evaluation value can be given based on a large variation in image data between the ridge portion and the ridge gap. In addition, it is possible to recognize a portion where a ridge is missing or a portion where a ridge is crushed in a fingerprint image, and to give a larger evaluation value as the ratio of those portions is lower. Further, the evaluation value can be determined based on the number of feature points detected in the fingerprint image and the sharpness thereof. Further, in order to perform fingerprint collation with high accuracy, a certain number of feature points are required, and in order to satisfy this, the contact area between the finger and the finger placement unit 40 is considered to be more than a certain amount in the evaluation value calculation. Also good.
[0031]
The processing in steps S115 to S125 is a fingerprint image reading operation once. The registration processing unit 62 repeats the fingerprint image reading operation at different timings T _k while sequentially incrementing the number k (S130). When the predetermined number of times (here, four times) is completed (S135), the repetitive operation ends. . The registration processing unit 62 compares the evaluation values _{V k} obtained for each fingerprint image _{P k} (S140), as best evaluation value registered fingerprint image _{P k} obtained fingerprint _{P R,} input at step S105 The information is stored in the storage unit 10 in association with the ID number of the registered person. The timing T _k obtained its registered fingerprint P _R, and the verification time T _R, stored in the storage unit 10 as one of the additional information of the object registrant (S145).
[0032]
Next, operations and processing at the time of fingerprint collation in this apparatus will be described. FIG. 4 is a process flow diagram during fingerprint collation. A person who seeks authentication by fingerprint collation, that is, a person to be collated is basically a registered user and obtains his / her ID number. The person to be verified inputs his / her ID number from the operation unit 24 (S200), and presses the finger against the finger placement unit 40. When the verification processing unit 60 is input the ID number, registered user information associated with the ID number, i.e. reads the registered fingerprint _{P R,} the matching timing _{T R} from the storage unit 10 (S205).
[0033]
Next, in the operation of reading the fingerprint of the person to be collated pressed against the finger placement unit 40, the pressure of the finger pressed against the fingerprint reading sensor 30 by the person to be collated is set in the pressure switch 32 as in the case of the fingerprint registration. It is activated when it exceeds the predetermined value. When the pressure exceeds a predetermined value, the pressure switch 32 is turned on (S210), and the verification processing unit 60 measures the elapsed time from the time when the pressure is turned on. When the elapsed time is collated timing _{T R,} the verification processing unit 60 drives the fingerprint reading sensor 30 captures a fingerprint image of the collation time _{T R} (collation fingerprint _{P S)} (S215). Note that the pressure setting value at which the pressure switch 32 is turned on is the same during the registration process and during the verification process.
[0034]
Matching process section 60, the registered fingerprint _{P R} read by the collation fingerprint _{P S} and step S205 (S220). If the result of the collation determination is acceptable (S225), the collation processing unit 60 notifies the control unit 12 of the main body module 2 as a process at the time of the pass, and the control unit 12 may, for example, unlock the electric lock at the entrance. Processing such as locking is performed (S230). On the other hand, if the result of the collation determination is a failure (S225), the collation processing unit 60 performs a process at the time of the failure (S235). For example, the matching processing unit 60 displays a message and the collation fingerprint P _S indicating that failed on the display unit 26. For example, the collation processing unit 60 notifies the control unit 12 of an abnormality when, for example, the same person to be collated fails a predetermined number of times.
[0035]
In the above configuration, when a plurality of fingerprint images with different timings are captured, the registered person presses the finger placement unit 40 each time to turn on the pressure switch 32. On the other hand, when the pressure switch 32 is turned on once, the registration processing unit 62 may be configured to sequentially capture fingerprint images at different timings.
[0036]
Further, the structure is such that the verifier inputs the ID number, the registered fingerprint and P _R associated with that ID number and the collation fingerprint P _S are collated one to one. Here, for example, in a case of the apparatus and for home, matching because fewer people of the registrant, omit the input of the ID number, the collation fingerprint P _S and the registered fingerprint P _R of all registered users Even in such a configuration, the time required for collation is within an allowable range. In this configuration, no ID input is required, so it is not necessary to memorize the ID number, and anyone can easily operate. In this case, it may have different collation timing T _R for each registered fingerprint P _R. Here again, the verification processing unit 60 compares the registered fingerprint and the verification fingerprint with the same verification timing. For this purpose, for example, when the pressure switch 32 is turned on once, the verification processing unit 60 is configured to capture fingerprint images at different timings one after another and capture fingerprint images at each verification timing. Then, among the plurality of fingerprint images collected from the person to be collated, one having the same timing as the registered fingerprint to be collated is selected as the collation fingerprint, and collation determination is performed.
[0037]
【The invention's effect】
According to the fingerprint collation apparatus of the present invention, the fingerprint registration method and the fingerprint collation method used therefor, a registered fingerprint suitable for collation is determined for each individual, so that collation accuracy is improved.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of a fingerprint collation apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of a fingerprint input unit.
FIG. 3 is a processing flow diagram at the time of fingerprint registration.
FIG. 4 is a processing flow diagram at the time of fingerprint collation.
[Explanation of symbols]
2 Main unit module, 4 operation module, 10 storage unit, 12 control unit, 20 fingerprint input unit, 22 processing unit, 24 operation unit, 26 display unit, 30 fingerprint reading sensor, 32 pressure switch, 40 finger placement unit, 44 light source, 48 imaging device, 50 pressure sensing unit, 60 collation processing unit, 62 registration processing unit.

Claims (2)

In a fingerprint collation device that reads an input fingerprint from a finger pressed against a fingerprint reading sensor and collates the input fingerprint with a registered fingerprint registered in advance,
A pressure switch that is turned on when the pressure of the finger against the fingerprint reading sensor exceeds a predetermined value;
A registration processing unit for determining and registering the registered fingerprint of the registered person based on the input fingerprint of the registered person;
Have
The registration processing unit
For any of the registered persons, a registered person fingerprint sampling unit that reads a plurality of the input fingerprints by the fingerprint reading sensor by changing the reading timing from the time when the pressure switch is switched to the ON state ;
A selection unit that selects, as the registered fingerprint, a plurality of the input fingerprints obtained for the arbitrary registered person, which is suitable for the verification;
Registration means for registering the registered fingerprint and the reading timing corresponding to the registered fingerprint in association with the registered person ;
A fingerprint verification device characterized by the above. The fingerprint verification apparatus according to claim 1, wherein
When the pressure switch is turned on by a person to be collated with the person to be registered, a person to be verified fingerprint that reads an input fingerprint of the person to be verified at the reading timing registered for the person to be registered A fingerprint collation device comprising sampling means .

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