Blood pulse wave detecting apparatus and motion intensity measuring apparatus

• US 6,022,321 A
• Filed: 02/28/1997
• Issued: 02/08/2000
• Est. Priority Date: 09/28/1993
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kitazawa, Koji, Hayakawa, Motomu, Amano, Kazuhiko
• Primary Examiner(s): Hindenburg, Max
• Assistant Examiner(s): CARTER, RYAN CHRISTOPHER
• Application Number:
  US08/808,523
• Time in Patent Office: 1,075 Days
• Field of Search: 600/484-485, 600/500-501, 600/310
• US Class Current: 600/500
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• 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 5/1118 Determining activity level
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/6826 Finger
• 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

An apparatus for detecting pulse waves and motion intensity of a living body in motion is disclosed. The apparatus has photosensors of the photo-coupler type for wavelengths of 660 nm and 940 nm, respectively. The sensors are attached to a person under examination, and provide output signals which include a blood pulse signal as well as body motion components superimposed on the blood pulse signal. These signals are subjected to the Fourier transformation in a fast Fourier transformation circuit, and then applied to a comparator which in turn compares amplitudes of major frequency components (components associated with pulse waves and body motion) to one another. According to the comparison result, a decision circuitdiscriminates the pulse wave from the body motion. A display unit displays the pulse rate corresponding to the fundamental frequency of the detected pulse wave. The display unit also displays the change in motion intensity detected by the decision circuit. Thus, the present invention allows the detection of the change in motion intensity during the exercise of a person under the examination.

Claims

1. A blood pulse wave detecting apparatus, comprising:

light emitting means for emitting a plurality of light beams having different wavelengths to illuminate a part of a living body;

light detecting means for detecting light transmitted through or reflected from the living body illuminated by the light beams and producing a plurality of detected signals, each detected signal corresponding to an emitted light having one of said wavelengths, each detected signal including a plurality of frequency components; and

discrimination means for discriminating a blood pulse wave of the living body from its body motion wave, comprising means for comparing an amplitude ratio of preselected frequency components associated with one of the plurality of detected signals with an amplitude ratio of the preselected frequency components associated with another one of the plurality of detected signals and wherein said discrimination means discriminates a blood pulse wave of the living body from its body motion wave according to a comparison between the amplitude ratios of the preselected frequency components.

2. The blood pulse wave detecting apparatus according to claim 1, wherein said light emitting means and said light detecting means are arranged in a lateral direction of a finger of the living body.

3. The blood pulse wave detecting apparatus according to claim 1, further comprising means for supplying electric power to said light detecting means and said discrimination means only when a measurement of the blood pulse frequency is carried out.

4. The blood pulse wave detecting apparatus according to claim 3, wherein the measurement is carried out in an intermittent fashion.

5. The blood pulse wave detecting apparatus according to claim 3, wherein the electric power is supplied in a pulse current form.

6. A blood pulse wave detecting apparatus, comprising:

light emitting means for emitting a plurality of light beams having different wavelengths to illuminate a part of a living body;

light detecting means for detecting light transmitted through or reflected from the living body illuminated by the light beams and producing a plurality of detected signals each corresponding to an emitted light having one of said wavelengths;

frequency analyzing means for performing frequency analysis on each of the plurality of detected signals to produce a plurality of associated frequency components for each of the detected signals; and

blood pulse frequency identifying means for identifying a blood pulse frequency of the living body from its body motion frequency, comprising means for comparing an amplitude ratio of preselected frequency components of one of the plurality of detected signals with an amplitude ratio of the preselected frequency components of another one of the plurality of detected signals.

7. The blood pulse wave detecting apparatus according to claim 6, further comprising:

storage means for storing the blood pulse frequency identified by said blood pulse frequency identifying means; and

display means for displaying the blood pulse frequency stored in said storage means.

8. A blood pulse wave detecting apparatus of claim 6,

wherein said frequency analyzing means comprises Fourier transformation means for performing Fourier transformation on each of the plurality of detected signals to produce a frequency spectrum associated with each of the detected signals;

and

wherein said blood pulse frequency identifying means identifies the blood pulse frequency of the living body from its body motion frequency by comparing an amplitude ratio of preselected frequency components in one frequency spectrum of one of the detected signals with an amplitude ratio of preselected frequency components in one frequency spectrum of another one of the detected signals.

9. The blood pulse wave detecting apparatus of claim 8, further comprising:

filtering means for passing only a selected frequency component and its harmonics from a selected one of the plurality of detected signals produced by said light detecting means, the selected frequency component corresponding to the blood pulse frequency identified by said blood pulse frequency identifying means.

10. The blood pulse wave detecting apparatus according to claim 10, further comprising:

waveform storing means for storing an output waveform corresponding to the selected frequency component and its harmonics provided by said filtering means; and

display means for displaying the output waveform stored in said waveform storing means.