Blood pulse wave detecting apparatus and motion intensity measuring apparatus

• US 6,217,523 B1
• Filed: 11/23/1999
• Issued: 04/17/2001
• 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:
  US09/448,622
• Time in Patent Office: 511 Days
• Field of Search: 600/485, 600/500-501, 600/310, 600/322, 600/481, 600/483
• 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 circuit discriminates 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 motion intensity measuring apparatus, comprising:

light detecting means for detecting the amount of light transmitted through or reflected from a living body illuminated with light having different wavelengths;

discrimination means for making comparison of amplitudes of frequency components associated with each said wavelength wherein said frequency components are included in a detected signal provided by said light detecting means, thereby discriminating a blood pulse wave of said living body from its body motion wave according to the relationships between the ratios of said amplitudes of frequency components; and

measuring means for making comparison of amplitudes of body motion associated with said different wavelengths wherein said amplitudes have been discriminated by said discrimination means, thereby measuring the motion intensity of said living body according to the change in the ratio of said amplitudes of body motion.

2. A motion intensity measuring apparatus according to claim 1, wherein light having such a wavelength at which the absorbance of oxygen hemoglobin is equal to that of reduced hemoglobin is used as one of said light having different wavelengths, and wherein said measuring means employs the amplitude of a blood pulse wave included in a detected signal associated with this light as a reference value, and compares the amplitude of a blood pulse wave included in a detected signal associated with another light to said reference value, thereby measuring said motion intensity of a living body.

3. A motion intensity measuring apparatus according to claim 1, wherein at least one of means including said light detecting means, said discrimination means and said measuring means is adapted to be supplied with electric power only when measurement is carried out.

4. A motion intensity measuring apparatus according to claim 3, wherein said electric power is supplied in a pulse current form.

5. A motion intensity measuring apparatus according to claim 1, wherein at least one of means including said light detecting means, said discrimination means and said measuring means is adapted to be supplied with electric power only when measurement is carried out at measurement timing which has been set in an intermittent fashion.

6. A motion intensity measuring apparatus according to claim 1, further including:

motion intensity storing means for storing a measurement result provided by said measuring means; and

display means for displaying the measurement result stored in said motion intensity storing means.

7. A motion intensity measuring apparatus according to claim 1, wherein said light detecting means includes a plurality of light emitting means for emitting light rays having different wavelengths, and further includes a plurality of light receiving means for receiving reflected light associated with the light rays emitted by respective said plurality of light emitting means, said plurality of light emitting means and said plurality of light receiving means being arranged in the lateral direction of a finger.

8. A motion intensity measuring apparatus, comprising:

light detecting means for detecting the amount of light transmitted through or reflected from a living body illuminated with light having different wavelengths;

discrimination means for making comparison of amplitudes of frequency components associated with each said wavelength wherein said frequency components are included in a detected signal provided by said light detecting means, thereby discriminating a blood pulse wave of said living body from its body motion wave according to the relationships between the ratios of said amplitudes of frequency components; and

measuring means for making comparison of the amplitude of the body motion to the amplitude of the blood pulse wave wherein the amplitudes of the body motion and blood pulse wave have been discriminated by said discrimination means, thereby measuring the motion intensity of said living body according to the change in the ratio between the amplitudes.