BIOLOGICAL STATE ESTIMATION DEVICE, BIOLOGICAL STATE ESTIMATION SYSTEM, AND COMPUTER PROGRAM

• US 20120259181A1
• Filed: 10/14/2010
• Published: 10/11/2012
• Est. Priority Date: 10/14/2009
• Status: Active Grant

• Current Assignee: Delta Tooling Co., Ltd. (Delta Kogyo Company Limited)
• Original Assignee: Delta Tooling Co., Ltd. (Delta Kogyo Company Limited)
• Inventors: Fujita, Etsunori, Ogura, Yumi, Maeda, Shinichiro, Ochiai, Naoki
• Granted Patent: US 10,136,850 B2
• Time in Patent Office: Days
• US Class Current: 600/300
• CPC Class Codes: A61B 5/18 for vehicle drivers or machine operators
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/4809 Sleep detection, i.e. determining whether a subject is asleep or not
• CPC Class Codes: A61B 5/6893 Cars
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/7242 using integration
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/744 Displaying an avatar, e.g. an animated cartoon character
• CPC Class Codes: B60W 2040/0872 Driver physiology

Abstract

A biological body state estimation device configured such that a homeostatic function level is sorted and acquired in plural stages by using a biological signal obtained from an upper body of a person and each stage of the homeostatic function level is plotted in time series in accordance with a time axis indicated on the lateral axis and displayed as a graph by a display. A highest part on the vertical axis of the graph can be displayed as a highly active state and a lowest part as a function decline state. Therefore, a state of fluctuation due to autonomous nerves as an attempt to maintain homeostasis, progress of a feeling of fatigue, and a state stimulated by activation of the brain can be captured as a periodic function. Moreover, a sleep prediction phenomenon can be captured.

Claims

1. A biological body state estimation device for estimating a state of a person using a biological signal obtained from an upper body of a person by using a biological signal measuring means, comprising:

homeostatic function level computing means that analyzes the biological signal, and acquires and sorts the homeostatic function level of a person at a predetermined point of time into a plurality of stages; and

output means that plots the homeostatic function level acquired by the homeostatic function level computing means in a time series by taking each stage of the homeostatic function level on the vertical axis and time on the lateral axis and displays a fluctuation degree of the homeostatic function level on display means as a graph.

2. The biological body state estimation device according to claim 1, wherein

the homeostatic function level computing means acquires and sorts the homeostatic function level into a range of 3 to 10 stages from a highly active state to a functional decline state, and the output means sorts and displays the level in a range of 3 to 10 stages on the vertical axis with the highly active state as the highest part and the functional decline state as the lowest part.

3. The biological body state estimation device according to claim 2, wherein

the homeostatic function level computing means acquires and sorts the homeostatic function level into five stages from the highly active state to the functional decline state;

and

the output means sorts and displays the level into five stages on the vertical axis with the highly active state as the highest part and the functional decline state as the lowest part.

4. The biological body state estimation device according to claim 1, further comprising:

determining means that determines a change in the state of a person from a graph displayed on the display means by the output means.

5. The biological body state estimation device according to claim 4, wherein

the determining means has abnormal state determining means that determines an abnormal state if a rapid decline over two stages or more of the homeostatic function level occurs a predetermined number of times or more on the graph displayed on the display means by the output means.

6. The biological body state estimation device according to claim 1, wherein

the homeostatic function level computing means includes:

frequency computing means that acquires a frequency of a biological signal obtained by the biological signal measuring means;

frequency slope time-series analyzing and computing means that conducts a movement calculation to acquire a slope of the frequency for each predetermined time window set with a predetermined overlapped time from the frequency of the biological signal obtained by the frequency computing means and acquires a time-series waveform of the slope of the frequency obtained for each time window;

differentiating means that differentiates the time-series waveform of the frequency slope acquired by the frequency slope time-series analyzing and computing means;

integrating means that integrates the time-series waveform of the frequency slope acquired by the frequency slope time-series analyzing and computing means;

rectangular wave calculating means that acquires a rectangular wave from increase/decrease of the time-series waveform of the frequency slope acquired by the frequency slope time-series analyzing and computing means;

describing function calculating means that acquires a describing function and a describing function amplitude value between the frequency slope time-series waveform in an arbitrarily set first time zone and the frequency slope time-series waveform in a second time zone after the first time zone;

absolute value processing means that applies absolute value processing to the time-series waveform of the respective frequency slopes acquired by the frequency slope time-series analyzing and computing means by using a time-series waveform of a frequency of a biological signal using a maximum value of the time-series waveform of the biological signal obtained by the frequency computing means and a time-series waveform of a frequency of a biological signal using a zero-crossing point where the sign of the time-series waveform of the biological signal is switched; and

homeostatic function stage calculating means that acquires the stage of the homeostatic function level by using at least one or more of the frequency slope acquired by the frequency slope time-series analyzing and computing means, the differential value acquired by the differentiating means, the integral value acquired by the integrating means, the sign of the rectangular wave acquired by the rectangular wave calculating means, the describing function amplitude value acquired by the describing function calculating means, and two absolute values of the frequency slope time-series waveform acquired by the absolute value processing means.

7. The biological body state estimation device according to claim 1, further comprising:

filtering means that filters the biological signal obtained by the biological signal measuring means in a predetermined frequency band before being processed by the homeostatic function level computing means, wherein

the filtering means is configured to set a frequency band for filtering by acquiring a mean frequency of the biological signal under a static environment measured by the biological signal measuring means and using the mean frequency as a reference value.

8. The biological body state estimation device according to claim 1, wherein

the biological signal measuring means is provided with an air pack brought into contact with the back part of a person and whose pressure fluctuates with fluctuation in aorta caused by movement of the heart;

and

the homeostatic function level computing means uses the pressure fluctuation of the air pack as the biological signal to be analyzed.

9. The biological body state estimation device according to claim 8, wherein

the air pack is equipped to a seatback section of an vehicle seat.

10. The biological body state estimation device according to claim 1, wherein

the display means is an onboard monitor.

11. A biological body state estimation system comprising:

biological signal measuring means that obtains a biological signal from an upper body of a person; and

a biological body state estimation device that estimates the state of a person using the biological signal obtained by the biological signal measuring means, wherein

the biological body state estimation device includes;

homeostatic function level computing means that analyzes the biological signal, and acquires and sorts a homeostatic function level of a person at a predetermined point of time into a plurality of stages; and

output means that plots the homeostatic function level acquired by the homeostatic function level computing means in a time series with each stage of the homeostatic function level on the vertical axis and time on the lateral axis and displays a degree of fluctuation in the homeostatic function level on display means as a graph.

12. The biological body state estimation system according to claim 11, wherein

the biological signal measuring means is provided with an air pack brought into contact with the back part of a person and whose pressure fluctuates with fluctuation in aorta caused by movement of the heart;

and

the homeostatic function level computing means uses the pressure fluctuation of the air pack as the biological signal to be analyzed.

13. The biological body state estimation system according to claim 12, wherein

the air pack is equipped to a seatback section of an vehicle seat.

14. The biological body state estimation system according to claim 11, wherein

the display means is an onboard monitor.

15. A computer program incorporated in the biological body state estimation device that estimates the state of a person by using a biological signal obtained from the upper body of a person by the biological signal measuring means, comprising:

a homeostatic function level computing step that analyzes the biological signal, and acquires and sorts the homeostatic function level of a person at a predetermined point of time into a plurality of stages; and

an output step that plots the homeostatic function level acquired by the homeostatic function level computing step in a time series with each stage of the homeostatic function level on the vertical axis and time on the lateral axis and displays it by the display means as a graph.

16. The computer program according to claim 15, wherein

the graph displayed by the display means by the output step is a line graph.

17. The computer program according to claim 15, wherein

the homeostatic function level computing step acquires and sorts the homeostatic function level into five stages from the highly active state to the functional decline state;

and

the output step sorts and displays the homeostatic function level in five stages with the highly active state as the highest part and the functional decline state as the lowest part on the vertical axis.

18. The computer program according to claim 15, further comprising:

a determining step that determines a change in the state of a person from a graph displayed on the display means by the output step.

19. The computer program according to claim 18, wherein

the determining step has an abnormal state determining step that determines an abnormal state if a decline over two stages or more of the homeostatic function level occurs a predetermined number of times or more on the graph displayed on the display means by the output step.

20. The computer program according to claim 15, wherein

the homeostatic function level computing step includes:

a frequency computing step that acquires a frequency of a biological signal obtained by the biological signal measuring means;

a frequency slope time-series analyzing and computing step that conducts a movement calculation to acquire a slope of the frequency for each predetermined time window set with a predetermined overlapped time from the frequency of the biological signal obtained by the frequency computing step and acquires a time-series waveform of the slope of the frequency obtained for each time window;

a differentiating step that differentiates the time-series waveform of the frequency slope acquired by the frequency slope time-series analyzing and computing step;

an integrating step that integrates the time-series waveform of the frequency slope acquired by the frequency slope time-series analyzing and computing step;

a rectangular wave calculating step that acquires a rectangular wave from increase/decrease of the time-series waveform of the frequency slope acquired by the frequency slope time-series analyzing and computing step;

a describing function calculating step that acquires a describing function and a describing function amplitude value between the frequency slope time-series waveform in an arbitrarily set first time zone and the frequency slope time-series waveform in a second time zone after the first time zone;

an absolute value processing step that applies absolute value processing to the time-series waveform of the respective frequency slopes acquired by the frequency slope time-series analyzing and computing step by using a time-series waveform of a frequency of a biological signal using a maximum value of the time-series waveform of the biological signal obtained by the frequency computing step and a time-series waveform of a frequency of a biological signal using a zero-crossing point where the sign of the time-series waveform of the biological signal is switched; and

a homeostatic function stage calculating step that acquires the stage of the homeostatic function level by using at least one or more of the frequency slope acquired by the frequency slope time-series analyzing and computing step, the differential value acquired by the differentiating means, the integral value acquired by the integrating means, the sign of the rectangular wave acquired by the rectangular wave calculating means, the describing function amplitude value acquired by the describing function calculating step, and two absolute values of the frequency slope time-series waveform acquired by the absolute value processing step.