JP2000258268A - Pressure-measuring device, individual identification system and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability of a device and enable a simple and easy identification at a low cost by measuring a pressure applied through a flexible container filled with a fluid by means of a plurality of micro pressure-sensors arranged in an array. SOLUTION: An individual identification system 1 to identify a user P of a computer 2 comprises pressure sensors 4a to 4d provided e.g. to each part of a chair 3, and formed of a number of micro pressure sensors arranged in a matrix to detect a pressure applied by the user P. The micro pressure-sensor is provided with a piezoelectric element to output a pressure signal in a fluid inside a flexible container filled with the fluid such as air, etc., and a signal wire 44 from the piezoelectric element to the computer 2 is led out. When the user P sits on the chair 3 and a pressure of a specified value or more is given to the pressure sensors 4a to 4d, the computer 2 measures the pressure distribution for a specified time and extracts a characteristic information from changes with time elapse, and the information is checked against a registered information, and judges whether or not the user P is registered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure measuring device for measuring a pressure at which a human body comes into contact with a chair or bedding, and a personal identification suitable for controlling access to a system such as a computer system and a data communication system. The present invention relates to a device and a personal identification method, and more particularly to a pressure measurement device with excellent durability, and a personal identification device and a personal identification method capable of easily and inexpensively identifying a subject.

[0002]

2. Description of the Related Art In computer systems, data communication systems, and the like, hardware, software, and information are constantly exposed to risks such as destruction and abuse. In order to protect the system from such danger, a personal identification device that permits the use of the system only to a registrant has been conventionally used. For this personal identification device, a password system in which a user name and a password are registered in advance and the user is limited and permitted is widely used.

[0003] However, since there are problems such as the password being stolen or the user forgetting the password, the user's invariant biometric information (fingerprint,
Personal identification methods using handprints, face shapes, eyelids, voiceprints, etc.)
For example, it is disclosed in JP-A-5-224777.

In this personal identification method, unique pressure distribution information due to the physical characteristics of a registrant is stored in a memory in advance as registration information, and the pressure distribution information concerning the user is measured when the computer system is used. Then, the pressure distribution information obtained by this measurement is compared with the registered information to determine whether the user is a registrant.

[0005] However, human beings always unconsciously move something without being conscious of moving. Therefore, since the pressure distribution information obtained from the subject to be identified is constantly fluctuating, it is very difficult to obtain constant and unique pressure distribution information from the subject using the conventional individual identification method. difficult. On the other hand, when trying to obtain constant pressure distribution information while fixing the movement of the subject, a large physical and psychological burden is imposed on the subject.

Therefore, as a conventional personal identification method which has been made in view of such a defect, for example, Japanese Patent Laid-Open No.
There is one disclosed in Japanese Patent No. 5825.

In the personal identification method disclosed in Japanese Patent Application Laid-Open No. 8-145825, pressure distribution information when an object comes into contact with a predetermined surface is chronologically acquired by a pressure sensor, and a plurality of pressure information obtained by the pressure sensor is obtained. The position information is normalized with respect to the distribution information, the pressure distribution information after position normalization is superimposed to create a superimposed pressure distribution image, the characteristics of the pressure distribution shape are extracted from the superimposed pressure distribution image, and the attributes of the object are extracted. To identify. According to this method, by extracting the characteristics of the pressure distribution shape from the superimposed pressure distribution image, the shape when the subject is at rest can be estimated, so that the pressure distribution information that is almost constant regardless of the subject's movements Can be obtained.

On the other hand, measuring devices for measuring pressure distribution have been conventionally developed mainly for the purpose of evaluating the performance of chairs, beddings and the like. As this conventional measuring device, a band-shaped cloth is arranged in a grid on a measuring surface, and a pressure distribution is measured based on a force applied by the pressure measured by the band-shaped cloth, or a color is obtained when pressure is applied. There is a method of measuring pressure using a changing paper, and a method of measuring pressure distribution by applying a pressure-sensitive resistive substance in a grid between a pair of electrodes in a matrix.

A measuring device for measuring pressure distribution by applying a pressure-sensitive resistive substance in a grid form is superior to other devices in that it can perform measurement in real time and can be downsized. .

[0010]

However, according to the conventional personal identification method, a processing device for normalizing the position of the pressure distribution information is required, which causes a problem that the cost is increased.

According to the conventional measuring device, a pressure is applied to the pressure-sensitive substance in a direction other than the pressure-sensitive direction (direction toward the electrode) by an unconscious operation performed by the subject, so that the electrode and the pressure-sensitive substance are separated. Therefore, there is a problem that the accuracy of the measuring instrument is reduced and durability is poor. Further, in order to maintain the accuracy of the measuring instrument, it is necessary to periodically replace the measuring instrument, and as a result, a large cost for maintaining the system is required.

Accordingly, it is an object of the present invention to provide a pressure measuring device having excellent durability. It is another object of the present invention to provide a personal identification device and a personal identification method capable of identifying a subject simply and at low cost.

[0013]

In order to achieve the above object, the present invention provides a flexible container filled with a fluid, and a detecting element for detecting a pressure applied to the fluid via the flexible container. A pressure measuring device provided with a plurality of minute pressure sensors arranged in an array. According to the above configuration, the detection element indirectly detects the pressure applied to the flexible container via the fluid.

[0014] In order to achieve the above object, the present invention provides a storage means for storing characteristics of a registrant's operation as registration information;
A measuring unit that measures a pressure generated by a user's operation in a time series and outputs a pressure signal; a feature extracting unit that extracts feature information of the user from a waveform of the pressure signal; and the feature information and the registration. A determination unit that determines whether the user is the registrant by collating information with the registrant. According to the above configuration, by extracting the characteristic information from the waveform of the pressure signal, a processing device for normalizing the signal is not required.

According to the present invention, in order to achieve the above object, a feature of a registrant's operation is registered as registration information, a pressure generated by a user's operation is measured in time series, and a pressure signal is output. Extracting a feature information of the user from a waveform of a pressure signal, and comparing the feature information with the registration information to determine whether the user is the registrant or not. I will provide a.

[0016]

FIG. 1 shows a personal identification system according to an embodiment of the present invention. This personal identification system 1
Are the computer body 2a, the CRT display 2b,
A computer 2 having a keyboard 2c and the like; a chair 3 for a user P using the computer 2; And Pressure sensor 4
Signal lines 44 are connected to the computer main body 2a from a to 4d.

FIG. 2A shows the chair 3 on which the pressure sensors 4a to 4d are arranged. The pressure sensors 4a to 4d are arranged on the seat surface 3a, the back surface 3b, the armrest surface 3c, and the footrest surface 3d of the chair 3 so as to be invisible to the user P, as shown in FIG. As a result, since the measurement is not understood by the user P, the psychological burden on the user P is eliminated, and the user P sits on the chair 3 in a natural state. As a result, the user P Makes it possible to measure the pressure caused by the unconscious movement of the person. In addition, by disposing the pressure sensors 4a to 4d in each part of the chair 3, it is possible to cope with any posture of the user P.

FIGS. 2B and 2C show the pressure sensors 4a to 4a.
4d shows one pressure sensor 4 of 4d. Pressure sensor 4
Is composed of a large number of minute pressure sensors 40 arranged in a matrix as shown in FIG. The micro pressure sensor 40 includes a fluid 41 in a flexible container 42 filled with a fluid 41 such as air, as shown in FIG.
A piezoelectric element 43 that outputs a pressure signal corresponding to the internal pressure is desired, and a signal line 44 extending from the piezoelectric element 43 to the computer main body 2a is derived.

The flexible container 42 is preferably made of a material having high airtightness and high flexibility. Specifically, rubber and polyester are desirable from the viewpoint of cost and the like.

In this embodiment, air is used as the fluid 41. However, the present invention is not limited to this, and other fluids such as water, oil, and silicon can be used. By indirectly transmitting the pressure to the fluid 41 via the flexible container 42, the burden on the subject when measuring the pressure can be reduced. Further, by transmitting pressure indirectly, an extra force such as friction is not applied to the measurement system, so that a decrease in measurement accuracy can be prevented.

FIG. 3 shows a main control system of the system 1. The system 1 includes a sensor control unit 5 that controls pressure sensors 4a to 4d to measure a pressure distribution, and a pressure sensor 4
a plurality of pressure signals from a to 4d are stored in a memory (not shown), and feature information is extracted from these pressure signals. A feature information extraction unit 6 extracts feature information and a registration information storage unit 7. And an identification unit 8 for collating with the registration information stored in the storage unit. The sensor control unit 5, feature extraction unit 6, registration information storage unit 7, and identification unit 8 are housed in the computer main body 2a. In the registration information storage unit 7, the registrant is seated on the chair 3, and the registrant's feature information extracted by the feature extraction unit 6 from a plurality of pressure signals measured by the pressure sensors 4a to 4d is stored as registration information. ing.

Although the pressure sensor 4 is applied to the personal identification device in the above embodiment, the invention is not limited to this, but is applied to a pressure measurement device for measuring the pressure at which the human body comes into contact with a chair or bedding. be able to.

Next, the operation of the present system 1 will be described. First, the user P sits on the chair 3 to use the computer 2. The user P sits on the chair 3 and the pressure sensor 4
When a certain pressure or more is applied to the sensors a to 4d, the sensor control unit 5
Starts measurement using the weight distribution applied to the surface where the user P touches the chair 3 as a matrix-like pressure distribution. After that, the sensor control unit 5 measures the pressure distribution for a certain period of time and outputs it to the feature extraction unit 6.

FIG. 4 shows the time variation of the average value of the pressure.
The horizontal axis represents time, and the vertical axis represents pressure, and shows the time variation of the average value of the pressure from the minute pressure sensor 40 constituting the pressure sensor 4a provided on the seating surface 3a. The feature extraction unit 6 extracts the user's feature information from the time change of the pressure distribution obtained from the sensor control unit 5. That is, the feature extracting unit 6 obtains the time variation of the average value of the pressure for each of the pressure sensors 4a to 4d. The feature extracting unit 6 differentiates the average signal waveform to obtain a local minimum value, obtains a difference between the local minimum value and the local maximum value immediately before the local minimum value, and extracts a local minimum value whose difference is equal to or more than a predetermined value (FIG. 4 ×
Shown by a mark. ), The number of local minimum values per predetermined time (for example, 10 minutes) (the number of pressure fluctuations) is determined. By performing such feature information extraction processing, in the example shown in FIG. 4, data of person A is obtained five times, person B is obtained 47 times, and person C is obtained 172 times. The feature extraction unit 6 outputs the number of pressure fluctuations to the identification unit 8 as feature information.

The identification unit 8 compares the feature information from the feature extraction unit 6 with the number of pressure fluctuations registered as registration information in the registration information storage unit 7 to determine whether the user is a registrant. I do. For example, if the difference between the registered pressure fluctuation number and the extracted pressure fluctuation number is equal to or less than a certain value is registered in the registration information, the user is determined to be a registrant.

According to the above-described embodiment, since the pressure is indirectly detected via the fluid 41, the piezoelectric element 4
No excessive force is applied to 3, so that it has excellent durability. Further, since the minute pressure sensors are closely arranged, only the pressure in the direction orthogonal to the plane on which the minute pressure sensors are arranged is detected, so that accurate pressure can be detected. In addition, since feature information is extracted from changes in pressure, unlike conventional identification based on pressure distribution information, there is no need to restrict the movement of the subject or to perform measurement with the measuring instrument fixed to the subject. The pressure distribution can be measured without imposing a psychological or physical burden on the user. Further, by measuring the change in the pressure distribution, even if the position of the subject touching the minute pressure sensor 40 is slightly shifted due to the movement of the subject, the characteristic information can be extracted from the change in the pressure distribution. Since a processing device for normalizing is unnecessary, the subject can be identified simply and at low cost.

In this embodiment, the time variation of the average value of the pressure is used. However, the maximum amplitude, the average value of the amplitude, the variance of the amplitude, the maximum value of the interval between peaks, the interval between peaks, , A peak-to-peak variance, or the like, to determine whether the user is a registrant. Further, in the present embodiment, the pressure sensor is installed on the surface of the chair. However, the place where the pressure sensor is installed is not limited to the chair, but may be any location where the registrant is always in contact when using the system. For example, if a user who uses the system always uses a desk, it may be installed on the work surface of the desk. The pressure distribution information does not need to be temporally continuous. If a fluctuating pressure distribution is obtained, discrete information is also possible.

[0028]

As described above, according to the pressure measuring device of the present invention, since the pressure is indirectly detected through the fluid, an excessive force is not applied to the piezoelectric element, so that the durability is improved. And a pressure measuring device excellent in quality can be provided. Further, according to the personal identification device and the personal identification method of the present invention, since the characteristic information is extracted from the waveform of the pressure signal, a processing device for normalizing the signal is not required, and the subject can be easily and inexpensively manufactured. Can be identified.

[Brief description of the drawings]

FIG. 1 is a diagram showing a personal identification system to which a personal identification device according to an embodiment of the present invention is applied.

2A is a perspective view of a chair according to an embodiment of the present invention, FIG. 2B is a diagram showing a pressure sensor, and FIG. 2C is a cross-sectional view of the pressure sensor.

FIG. 3 is a block diagram showing a main part of a control system of the personal identification system according to the embodiment of the present invention.

FIG. 4 is a diagram showing measurement results of pressure fluctuations by the personal identification system according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Personal identification system 2 Computer 3 Chair 4a-4d Pressure sensor 5 Sensor control part 6 Feature extraction part 7 Registration information storage part 8 Identification part 40 Micro pressure sensor 41 Fluid 42 Flexible container 43 Piezoelectric element 44 Signal line P User

Claims (13)

[Claims] 1. A plurality of minute pressure sensors arranged in an array comprising a flexible container filled with a fluid and a detection element for detecting a pressure applied to the fluid via the flexible container. A pressure measuring device characterized by the above-mentioned. 2. The pressure measuring device according to claim 1, wherein said plurality of minute pressure sensors are arranged on a seat surface of a chair. 3. A storage means for storing characteristics of a registrant's operation as registration information; a measuring means for measuring a pressure generated by a user's operation in a time series to output a pressure signal; and a waveform of the pressure signal. A feature extracting unit that extracts the feature information of the user from the computer; and a determining unit that determines whether the user is the registrant by comparing the feature information with the registration information. Characteristic personal identification device. 4. The apparatus according to claim 3, wherein said characteristic extracting means extracts at least an amplitude of a waveform of said pressure signal or an interval between peaks of a waveform of said pressure signal as said characteristic information.
Described personal identification device. 5. The personal identification device according to claim 3, wherein said measuring means includes a plurality of minute pressure sensors arranged in an array for outputting a plurality of said pressure signals. 6. The personal identification device according to claim 5, wherein said characteristic extracting means extracts said characteristic information from a temporal variation of an average value of said plurality of pressure signals from said plurality of minute pressure sensors. 7. An individual according to claim 5, wherein said characteristic extracting means extracts said characteristic information from a waveform of said pressure signal indicating a maximum value among said plurality of pressure signals from said plurality of minute pressure sensors. Identification device. 8. The feature extracting means divides the plurality of minute pressure sensors into a plurality of regions, and calculates, for each of the regions, an average value of a plurality of the pressure signals from the plurality of minute pressure sensors belonging to the region. The personal identification device according to claim 5, wherein the characteristic information is extracted from time variation. 9. The measuring means comprises: a plurality of microscopically arranged microarrays each comprising a flexible container filled with a fluid, and a detecting element for detecting a pressure applied to the fluid via the flexible container. 4. The personal identification device according to claim 3, wherein the personal identification device is provided with a pressure sensor. 10. The storage device according to claim 1, wherein said storage unit stores the characteristic information measured by the measurement unit and extracted by the characteristic extraction unit from a waveform of the output pressure signal as the registration information. The personal identification device according to claim 3. 11. A feature of a registrant's operation is registered as registration information, a pressure generated by a user's operation is measured in time series, and a pressure signal is output. From the waveform of the pressure signal, the user's operation is registered. A personal identification method comprising: extracting feature information; and comparing the feature information with the registration information to determine whether the user is the registrant. 12. The personal identification method according to claim 11, wherein the output of the pressure signal is configured to measure an operation of the user unconsciously. 13. The personal identification method according to claim 11, wherein the output of the pressure signal is configured to measure the operation of the user at a plurality of locations.