JP2004258704A - Fingerprint collation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a correct determination even for a person with less perspiration in fingerprint collation. <P>SOLUTION: Fingerprint image data picked up by a fingerprint sensor 1 are stored in an image memory 2, and feature point data are extracted by image processing means 3. Collation processing means 5 collates the extracted feature point data against feature point data stored in a feature point data storage part 4 to determine the degree of matching of them both. Gray value calculating means 7A of false fingerprint determining means 7 calculate a time variation in the gray value of the fingerprint image data, and if the value is not larger than a prescribed value, fingerprint movement calculating means 7B calculates a time variation in the movement of the fingerprint image data, and determine on a false fingerprint if the value is smaller than a given value. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for collating input fingerprint image data with registered fingerprint image data.
[0002]
[Prior art]
In a conventional fingerprint collation device, a grayscale value of a pixel at the same position on an image captured at a predetermined time and a predetermined time after the predetermined time is detected and compared, and a forgery input is determined based on the result. (For example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-61-255481 (Page 499 (Example) and FIG. 4)
[0004]
[Problems to be solved by the invention]
In the conventional fingerprint collation apparatus as described above, since a fingerprint or a forged fingerprint is determined based on a temporal change in grayscale value of the fingerprint image data (due to a sweating action), when a person who sweats less is used, the forgery is forged. There is a problem that a fingerprint may be determined.
[0005]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and has as its object to provide a fingerprint collation device that enables even a person who has little sweating to make a correct determination.
[0006]
[Means for Solving the Problems]
The fingerprint matching device according to the present invention calculates a temporal change in the movement amount of the input fingerprint image data, and if the change in the movement amount is less than a predetermined value, the input fingerprint image data is based on the forged fingerprint. That is, it is determined that the
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIGS. 1 and 2 show an embodiment of the first, second and fifth aspects of the present invention. FIG. 1 is an overall configuration diagram and FIG. 2 is an operation flowchart.
In FIG. 1, a fingerprint sensor 1 includes a light source, a prism, an image sensor, and the like, captures a fingerprint image of a finger placed at a predetermined position, and outputs fingerprint image data. The image memory 2 stores the fingerprint image data from the fingerprint sensor 1.
[0008]
The image processing means 3 extracts feature point data necessary for collation from the fingerprint image data in the image memory 2. The feature point data storage unit 4 stores feature point data of fingerprint image data registered in advance. The matching processing means 5 performs a matching calculation of the feature point data of the fingerprint image data extracted by the image processing means 3 with the feature point data of the registered fingerprint image data stored in the feature point data storage section 4, and matches the two. Determine the degree.
[0009]
The result display unit 6 displays the result of the comparison by the comparison processing unit 5. The forged fingerprint determining unit 7 has a gray value calculating unit 7A and a fingerprint moving amount calculating unit 7B. The fingerprint image data from the image memory 2 or the feature point data from the image processing unit 3 is input, and the input fingerprint image is a forged fingerprint. It is determined whether there is. The fingerprint device power-off means 8 turns off the power of the fingerprint collation measure when the forged fingerprint determining means 7 determines that the fingerprint is a forged fingerprint.
[0010]
In the fingerprint matching device configured as described above, the fingerprint image data output from the fingerprint sensor 1 is stored in the image memory 2, and the feature point data is extracted by the image processing unit 3. The matching processing unit 5 compares the feature point data from the image processing unit 3 with the feature point data registered in the feature point data storage unit 4, determines the degree of coincidence between them, and displays the result in the result display unit 6. indicate.
[0011]
On the other hand, the forged fingerprint determining means 7 determines whether the input fingerprint is due to a human finger or a forged fingerprint. If the forged fingerprint is forged, it is displayed on the result display unit 6 to warn that it is a forged fingerprint. . Further, when the number of times of determination of forgery reaches a predetermined number, the fingerprint device power-off device 8 turns off the power supply of the fingerprint collation device to enhance security.
[0012]
Next, a forged fingerprint determination operation according to this embodiment will be described with reference to FIG. In step S1, fingerprint image data from the image memory 2 (feature point data of the image processing means 3 may be used) is obtained. In step S2, the gray value calculator 7A calculates the gray value G (t) (t is time) of the pixel of the fingerprint image data. In step S3, it is determined whether the time t is zero. If the time t is zero, the process returns to step S1, and if not, the process proceeds to step S4.
[0013]
In step S4, the absolute value of the difference between the gray value G (t = i) when t = i (i is an integer) and the gray value G (t = i + 1) when t = i + 1 is determined by a predetermined value Tg. Determine if: That is, if the difference between the gray values is larger than the predetermined value Tg, it means that the gray value has changed due to the sweating action, so it is determined to be due to the living body, and the process proceeds to step S5 to determine the fingerprint.
On the other hand, when the difference between the gray values is equal to or smaller than the predetermined value Tg, the process proceeds to step S6, and the movement amount M (t = i + 1) of the fingerprint is calculated from the fingerprint image data at t = i and t = i + 1.
[0014]
The movement amount M can be obtained by image pattern matching, which is a known technique. In step S7, it is determined whether the movement amount M (t) is equal to or greater than a predetermined value Tm. If the movement amount M (t) is equal to or greater than the predetermined value Tm, it is determined that the movement of the finger of the person is due to rotation, twist, or the like, and the fingerprint is determined in step S5. However, if the movement amount M (t) is less than the predetermined value, it is determined that the movement is caused by a non-living body in which the above phenomenon does not occur, and it is determined that the fingerprint is a counterfeit fingerprint in step S8.
Here, steps S1 to S4 constitute the gray value calculating means 7A, steps S6 and S7 constitute the fingerprint movement amount calculating means 7B, and steps S5 and S8 constitute the forged fingerprint determining means 7.
In this way, it is possible to correctly determine a person who has been determined to be a fake finger due to little sweating or the like.
[0015]
Embodiment 2 FIG.
FIG. 3 is an explanatory diagram of direction angle data showing one embodiment of the third invention of the present invention. 1 and 2 are also used in the second embodiment.
This embodiment is different from the first embodiment in that the fingerprint image data itself in the image memory 2 is used for the calculation of the amount of fingerprint movement. Is used. As shown in FIG. 3, the direction angle data 11 is global fingerprint data indicating the vortex of the fingerprint and the flow of the fingerprint.
By using the direction angle data 11 in this way, it is possible to reduce the calculation time of the fingerprint movement amount as compared with the case of the first embodiment.
[0017]
Embodiment 3 FIG.
FIG. 4 is an explanatory diagram of feature point data showing an embodiment of the fourth invention of the present invention. 1 and 2 are also used in the third embodiment.
In this embodiment, the fingerprint image data itself in the image memory 2 is used for calculating the amount of fingerprint movement in the first embodiment, whereas the fingerprint image data output by the image processing means 3 is image-processed. Is used. As shown in FIG. 4, the feature point data 11 is fingerprint data indicating the positions and angles of the end point 12a and the branch point 12b of the fingerprint.
[0018]
By using the feature point data 12 in this manner, it is possible to reduce the calculation time of the fingerprint movement amount as compared with the case of the first embodiment.
[0019]
【The invention's effect】
As described above, in the present invention, the temporal change of the movement amount of the input fingerprint image data is calculated, and if the change of the movement amount is less than the predetermined value, the input fingerprint image data is based on the forged fingerprint. , It is possible to correctly determine a person who has been determined to be a fake finger because of little sweating or the like.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing a first embodiment of the present invention.
FIG. 2 is an operation flowchart showing the first embodiment of the present invention.
FIG. 3 is an explanatory diagram of direction angle data showing Embodiment 2 of the present invention.
FIG. 4 is an explanatory diagram of feature point data showing a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fingerprint sensor, 2 Image memory, 3 Image processing means, 4 Feature point data storage part, 5 Matching processing means, 7 Forged fingerprint determination means, 7A Gray value calculation means, 7B Fingerprint movement amount calculation means, 8 Fingerprint device power-off device , 11 direction angle data, 12 feature point data.
S1 to S4 Shading value calculating means, S6, S7 Fingerprint moving amount calculating means, 7 Counterfeit fingerprint determining means.

Claims (5)

An apparatus which operates by being connected to a power supply and compares feature point data obtained by image processing of input fingerprint image data with feature point data registered in advance to determine the degree of coincidence between the two, Fingerprint moving amount calculating means for calculating a temporal change in the moving amount of the fingerprint image data, and a forged fingerprint for determining that the input fingerprint image data is a forged fingerprint if the moving amount is less than a predetermined value. A fingerprint matching device comprising: a determination unit. An apparatus which operates by being connected to a power supply and compares feature point data obtained by image processing of input fingerprint image data with feature point data registered in advance to determine the degree of coincidence between the two, Gray value calculating means for calculating a temporal change in the gray value of the fingerprint image data, fingerprint moving amount calculating means for calculating a temporal change in the moving amount of the input fingerprint image data, and the gray value A fingerprint matching device comprising: a forged fingerprint determination unit that determines that the input fingerprint image is a forged fingerprint if the movement amount is less than a predetermined value and the moving amount is less than a predetermined value. 3. The fingerprint moving amount calculating means according to claim 1 or 2, wherein the fingerprint moving amount calculating means calculates a temporal change of a moving amount of direction angle data obtained by image processing of the input fingerprint image data. Fingerprint collation device. 3. The fingerprint moving amount calculating means according to claim 1, wherein the fingerprint moving amount calculating means calculates a temporal change of a moving amount of the feature point data obtained by the image processing of the input fingerprint image data. Fingerprint collation device. The fingerprint matching device according to any one of claims 1 to 4, further comprising a fingerprint device power-off device that turns off the power when the number of times of determination of the forged fingerprint reaches a predetermined number.

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