Image analysis – Applications – Personnel identification
Reexamination Certificate
1998-07-29
2001-01-30
Boudreau, Leo H. (Department: 2721)
Image analysis
Applications
Personnel identification
Reexamination Certificate
active
06181808
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a living body discriminating apparatus.
A person check is performed by extracting a person's feature quantities by using fingerprint, voiceprint, face image, etc. These data are peculiar to every person, and the recognition rate is extremely increased by dealing with increased resolution digital data. However, there is a possibility that data which is not obtained from a person, i.e., forged data, may be erroneously recognized in case of checking artificial digital data. To solve this problem, such means as one in which a check as to whether the checked data of living body is performed by also taking daily life data, or one in which oral questions concerning the pertinent person are made when inputting data. A method as the former means is disclosed in, for instance, Japanese Patent Laid-Open Publication No. 4-241680. In this method, when inputting fingerprint, various excitements are given to the finger. If the finger is of a living body, it responds to the excitements sensed by it. Other methods as the former means are disclosed in Japanese Patent Laid-Open Patent Application No. 6-187430. These methods are to check the pulsation, blood pressure, etc. by using pressure sensor and to detect infrared rays emitted from the finger by using an infrared sensor. A method as the latter means is disclosed in Japanese Patent Laid-Open Publication No. 1-233556. In this method, it is verified that the subject person is living, i.e., exists, by giving him or her instructions.
However, in the method disclosed in Japanese Patent Laid-Open Publication No. 4-241680, in which when inputting the fingerprint various excitements are given to the finger and, if the finger is of a living body, it responds to the excitements sensed by it, the responding means is left to the will of the subject person. Therefore, the subject of the fingerprint check need not be the pertinent person, and this means that forging is possible. In the methods disclosed in Japanese Patent Laid-Open Application No. 6-187430, i.e., one in which the pulsation, blood pressure, etc. are checked by using a pressure sensor, and one in which infrared rays emitted from finger are detected by using an infrared sensor, also have problems. In the case of using the pressure sensor, signals involved are simple. Therefore, even in case of any thing other than living body it is possible to provide pulsation data or blood pressure data to the pressure sensor by applying pressure thereto. In the case of the infrared ray detection method, forging is also possible by mounting, for instance, an infrared radiator on the replica finger. In the method of verifying the subject person by giving him or her instructions, the living body is known as such in the stage of the oral questions. The method, therefore, is an auxiliary means for checking the pertinent person.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide a living body discriminating apparatus, which can verify that input data is not artifically reproduced data but data directly obtained from a living body.
According to the present invention, there is provided a living body discriminating apparatus comprising: fingerprint input sensor means on which a finger is placed when inputting fingerprint; a plurality of living body potential deriving means disposed as transparent sensors on the surface of the fingerprint input sensor means for measuring the potential difference between two muscle points of the finger; living body grounding electrode means provided on the fingerprint input sensor means for grounding the living body; living body data measuring means for amplifying signals obtained from the living body potential deriving means and the living body grounding electrode means; living body data analyzing means for performing potential measurement and frequency analysis of living body data obtained in the living body data measuring means by digitizing the data; and living body discriminating means for discriminating whether the data obtained by processing in the living body data analyzing means is of the living body.
Three elements are provided as the living body potential deriving means, two of the three elements being used to measure the potential difference between two muscle points of the finger, the remaining one of the elements being used as a living body grounding electrode. The fingerprint input sensor means has a finger guide for holding the finger at a constant position.
According to another aspect of the present invention, there is provided a living body discriminating apparatus comprising: a fingerprint sensor on which a finger is placed for inputting a fingerprint of the finger; at least two living body potential deriving electrodes provided on a surface of the fingerprint input sensor, for measuring the potential difference between two points of the muscle of the finger; a living body grounding electrode disposed on the fingerprint input sensor, for grounding the living body; a living body data measuring unit for amplifying signals obtained from the living body potential deriving units and the living body grounding electrode; a living body data analyzing unit for digitizing and frequency analyzing living body data measured in the living body data measuring unit; and a living body discriminating unit for discriminating whether obtained data is of a living body based on the analyzed result of the living body data analyzing unit.
The living body potential deriving electrodes and the living body grounding electrode are formed from a conductive oxide compound. The living body data measuring unit measures differences of the signals from the two living body potential deriving electrodes and the living body grounding electrode, and a difference between the two differences. The discrimination of the living body discriminating unit is performed based on the voltage amplitude and frequency range of the analyzed result of the living body data analyzing unit. The voltage range is 10 &mgr;V to 10 mV and the frequency is 2 Hz to 2 kHz. The discrimination is performed when the potential data exceeds the level for the trigger and does not exceed the threshold level within a predetermined time period. The frequency data is obtained by removing a power spectrum in a particular frequency band from the overall power spectrograph. At least three living body potential deriving electrodes are mounted on fingerprint input sensor. At least three living body potential deriving electrodes are mounted on fingerprint input sensor. The fingerprint input sensor unit has a finger guide for holding the finger at a constant position. The living body potential deriving electrodes is transparent.
By using a plurality of living body potential deriving electrodes and a living body grounding electrode, it is possible to obtain a finger muscle potential chart. The finger muscle potential chart shows potential vibrations and base line level variations according to the finger movement, as is made obvious in, for instance, “Muscle Motion Control”, Shokodo Co., Ltd., pp. 18-22.
With the present apparatus, discrimination as to whether a finger for inputting fingerprint is of living body may be performed by using a muscle potential chart, which is obtained from the sole operation when inputting the fingerprint. The direction of waveform variation in the chart is positive or negative depending on the polarities of the living body potential deriving electrodes. However, this data cannot be known by the person who inputs the fingerprint. This means that it is impossible to input forged signal from the outside. In addition, with transparent glass electrodes provided on the fingerprint input sensor, it is possible to hold the finger in contact with the electrodes without interrupting the fingerprint input. The discrimination as to whether the finger is of living body, can be obtained by measuring and analyzing living body data obtained by using the electrodes. This means which uses a muscle potential chart, permits prevention of
Boudreau Leo H.
Foley & Lardner
NEC Corporation
Werner Brian P.
LandOfFree
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