Pulse meter, method for controlling pulse meter, wristwatch-type information device, control program, storage medium, blood vessel simulation sensor, and living organism information measurement device

• US 8,303,512 B2
• Filed: 09/03/2008
• Issued: 11/06/2012
• Est. Priority Date: 03/19/2003
• Status: Active Grant

• Current Assignee: 138 East LCD Advancements Limited (Vector Capital Corporation)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Aoshima, Ichiro, Kosuda, Tsukasa, Zakoji, Makoto, Kawafune, Yutaka, Baba, Norimitsu
• Primary Examiner(s): Natnithithadha, Navin
• Application Number:
  US12/203,599
• Publication Number:
  US 20090005695A1
• Time in Patent Office: 1,525 Days
• Field of Search: 600500-504, 600/481, 600/483
• US Class Current: 600/500
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7257 using Fourier transforms

Abstract

The present invention realizes calculating a pulse rate accurately, even when a body movement component has no periodical characteristics, by surely removing the body movement component generated in a living organism from a pulse wave component. A pulse wave detecting section includes a pulse wave sensor and outputs a pulse wave detection signal to an MPU functioning as a body motion component removing section. A body motion sensor outputs a body motion detection signal corresponding to a body motion that affects the behavior of venous blood to the MPU. As a result, to the MPU removes the body motion component from the pulse wave detection signal based on the body motion detection signal. A pulse rate calculating section calculates the pulse rate based on the pulse wave detection signal from which the body motion component has been removed. The pulse rate is displayed on a liquid crystal display device.

Claims

1. A pulse meter adapted to be attached to a human body to measure a pulse, comprising:

a pulse wave detecting unit configured and arranged to detect a pulse wave based on a signal from a pulse wave sensor and output a pulse wave detection signal;

a body motion component removing unit configured and arranged to remove a body motion component contained in said pulse wave detection signal based on a relative positional difference in a vertical direction between a position of a heart of the human body and a position where said pulse meter is attached; and

a pulse rate calculating unit configured and arranged to calculate a pulse rate based on said pulse wave detection signal after said body motion component is removed.

2. The pulse meter as recited in claim 1, wherein

said body motion component removing unit is further configured and arranged to include a body motion detecting unit configured and arranged to detect said body motion component expressed as a function of said relative positional difference and output a body motion detection signal.

3. The pulse meter as recited in claim 2, wherein said body motion detecting unit includes a pressure sensor configured and arranged to detect said body motion component.

4. The pulse meter as recited in claim 3, wherein said pressure sensor is positioned in a vicinity of said pulse wave sensor.

5. The pulse meter as recited in claim 3, wherein said pressure sensor and said pulse wave sensor are substantially stacked together.

6. The pulse meter as recited in claim 1, wherein

said body motion component removing unit is further configured and arranged to include a difference detecting unit configured and arranged to detect said relative positional difference and output a body motion detection signal, and

a body motion component generating unit configured and arranged to generate said body motion component based on said relative positional difference.

7. The pulse meter as recited in claim 1, wherein

said difference detecting unit includes an angle sensor configured and arranged to detect said relative positional difference as an angle difference of an actual position of said pulse meter with respect to a reference angle.

8. The pulse meter as recited in claim 7, wherein said angle sensor is positioned in a vicinity of said pulse wave sensor.

9. The pulse meter as recited in claim 7, wherein said angle sensor and said pulse wave sensor are substantially stacked together.

10. The pulse meter as recited in claim 7, wherein said angle sensor is configured and arranged to detect said angle difference based on a stationary acceleration.

11. The pulse meter as recited in claim 7, wherein said angle sensor is configured and arranged to have a rotary spindle and detect said angle difference based on a rotational state of said rotary spindle.

12. The pulse meter as recited in claim 6, wherein

said difference detecting unit is configured and arranged to include

an angle compensating unit configured and arranged to compensate said angle difference according to said body motion component when said angle difference indicates said position where said pulse meter is attached is higher than said position of the heart of the human body by an amount greater than a threshold value.

13. The pulse meter as recited in claim 1, wherein

said body motion component removing unit is configured and arranged to include

a removal processing unit configured and arranged to subtract a body motion detection signal corresponding to said body motion component based on said relative positional difference from said pulse wave detection signal.

14. The pulse meter as recited in claim 1, wherein

said body motion removing unit is configured and arranged to include

a first frequency analyzing unit configured and arranged to execute a frequency analysis of a body motion component detection signal corresponding to said body motion component based on said relative positional difference and generate first frequency analysis data,

a second frequency analyzing unit configured and arranged to execute a frequency analysis of said pulse wave detection signal and generate second frequency analysis data, and

a removal processing unit configured and arranged to subtract said first frequency analysis data from said second frequency analysis data.

15. The pulse meter as recited in claim 1, wherein

said body motion component removing unit is configured and arranged to include

a filter coefficient generating unit configured and arranged to generate an adaptive filter coefficient based on a body motion component detection signal corresponding to said body motion component based on said relative positional difference, and

a removal processing unit configured and arranged to subtract said body motion component detection signal applied with said adaptive filter coefficient from said pulse wave detection signal.

16. The pulse meter as recited in claim 1, further comprising a body motion information detecting unit configured and arranged to detect at least one of a pitch and step counts from said body motion component based on said relative positional difference contained in said pulse wave detection signal.

17. A method for measuring a pulse of a human body by a pulse meter attached on the human body, comprising:

performing pulse wave detection signal outputting process for outputting a pulse wave detection signal detected by a pulse wave sensor of the pulse meter;

performing body motion component removing process, using a processor, for removing a body motion component contained in said pulse wave detection signal based on a relative positional difference in a vertical direction between a position of a heart of the human body and a position where said pulse meter is attached; and

performing pulse rate calculating process, using a processor, for calculating a pulse rate based on said pulse wave detection signal after said body motion component is removed.

18. A wristwatch type information device, comprising:

a pulse wave detecting unit configured and arranged to be placed on a pulse wave detection position of the human body to detect a pulse wave based on a signal from a pulse wave sensor and output a pulse wave detection signal; and

a main body configured and arranged to be placed on a wrist of the human body, said main body including

a body motion component removing unit configured and arranged to remove a body motion component contained in said pulse wave detection signal based on a relative positional difference in a vertical direction between a position of a heart of the human body and a position where said pulse wave detecting unit is attached,

a pulse rate calculating unit configured and arranged to calculate a pulse rate based on said pulse wave detection signal after said body motion component is removed, and

a display unit configured and arranged to display said pulse rate.

19. A computer readable medium having program code means embodied therein for controlling, by a computer, a pulse meter adapted to be attached to a human body to measure a pulse having a pulse wave detecting unit configured and arranged to output a pulse wave signal, said computer readable program code means comprising:

removing a body motion component contained in said pulse wave detection signal based on a relative positional difference in a vertical direction between a position of a heart of the human body and a position where said pulse meter is attached; and

calculating a pulse rate based on said pulse wave detection signal after said body motion component is removed.