Pulse counter and pulse display method

• US 6,099,478 A
• Filed: 11/12/1999
• Issued: 08/08/2000
• Est. Priority Date: 03/18/1997
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group), Seiko Instruments Incorporated (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group), Seiko Instruments Incorporated (Seiko Group)
• Inventors: Aoshima, Ichiro, Kosuda, Tsukasa
• Primary Examiner(s): O'Connor, Cary
• Assistant Examiner(s): Natnithithadha, Navin
• Application Number:
  US09/180,727
• Time in Patent Office: 270 Days
• Field of Search: 600/500, 600/502, 600/503, 600/501, 600/481
• US Class Current: 600/500
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: G04G 21/025 for measuring physiological data

Abstract

A pulse counter is provided in which the value displayed for the detected value is highly reliable. An SN condition detecting means detects the SN condition of a pulse wave signal (step S201). The SN condition detecting means then determines whether or not the detected SN condition is good based on a specific threshold value (step S202). When a determination is made that the SN condition is good, a display control signal to display the pulse rate on a display means is output to a display method switching means (step S203). Conversely, when a determination is made in step S202 that the SN condition is not good, the pulse rate is not displayed on the display means, but rather a display control signal indicating that no information at all be displayed is output to the display method switching means (step S204).

Claims

1. A pulse counter comprising:

a first calculating means for carrying out frequency analysis of a pulse wave signal detected by a pulse wave detecting means;

a second calculating means for carrying out frequency analysis of a body motion signal detected by a body motion detecting means;

a pulse wave extracting means for calculating the pulse rate by extracting the frequency of the pulse based on the results of frequency analysis by the first and second calculating means;

a display means for displaying information at least including the output of the pulse wave extracting means;

a SN condition detecting means for determining whether or not a noise component exceeding a specific value is included in at least one of the results obtained from frequency analysis by the first calculating means and frequency analysis by the second calculating means; and

a display method switching means for switching display contents in the display means in response to results detected by the SN condition detecting means.

2. A pulse counter according to claim 1, wherein the pulse wave extracting means calculates the pulse rate by extracting the frequency of the pulse based on the results of frequency analysis by the first calculating means and the second calculating means, and calculates the body motion pitch which is a function of the period of the body motion.

3. A pulse counter according to claim 2, wherein the display method switching means does not perform a display on the display means when the SN condition detecting means determines that a noise component exceeding a specific value is included.

4. A pulse counter according to claim 2, wherein the display method switching means carries out a blinking display on the display means when the SN condition detecting means determines that a noise component exceeding a specific value is included.

5. A pulse counter according to claim 2, wherein, when the SN condition detecting means determines that a noise component exceeding a specific value is included, the display method switching means displays the pulse rate or body motion pitch calculated by the pulse wave extracting means, and displays an indication that the probability of an error in the displayed value is high.

6. A pulse counter according to claim 2, wherein the SN condition detecting means determines whether or not a noise component exceeding a specific value is included based on the state of each base line spectrum in the pulse wave signal spectrum.

7. A pulse counter according to claim 2, wherein the SN condition detecting means determines whether or not a noise component exceeding a specific value is included based on the state of each base line spectrum in the body motion signal spectrum.

8. A pulse counter according to claim 2, wherein the SN condition detecting means determines whether or not a noise component in excess of the specific value is included based on whether or not the ratio of the power between the base line spectrum having the maximum power in the pulse wave signal spectrum and the base line spectrum which is deemed to be the base line spectrum of the noise component is greater than a specific threshold value.

9. A pulse counter according to claim 2, wherein the SN condition detecting means determines whether or not a noise component in excess of the specific value is included based on whether or not the ratio of the power between the base line spectrum having the maximum power in the body motion signal spectrum and the base line spectrum which is deemed to be the base line spectrum of the noise component is greater than a specific threshold value.

10. A pulse counter according to claim 9, wherein the SN condition detecting means aligns each of the base line spectrums in order of largest powder, and designates the base line spectrum at a given position from the base line spectrum having the maximum power as the base line spectrum of the noise component.

11. A pulse counter according to claim 9, wherein, in the spectrum, the SN condition detecting means designates the base line spectrum which is located at a position which is separated from the base line spectrum having the maximum power by a given base line spectrum only as the base line spectrum of the noise component.

12. A pulse counter according to any one of claims 1 through 11, wherein:

the SN condition detecting means determines whether or not a noise component which will cause an error in the calculation of the pulse rate is included in at least one of the results of frequency analysis by the first calculating means and frequency analysis by the second calculating means, sets a specific standard value based on the results obtained up through the previous calculation by the pulse wave extracting means;

sets upper and lower limits for this standard value based on the results detected by the SN condition detecting means; and

determines whether or not the pulse rate or body motion pitch calculated by the pulse wave extracting means is within the window defined by these upper and lower limits; and

the display method switching means switches the details of the display on the display means based on the determination of the SN condition detecting means.

13. A pulse counter according to claim 12, wherein, when the SN condition detecting means determines that the pulse rate or body motion pitch are within the window, the display method switching means displays an indication on the display means that the probability of an error in the displayed value is high.

14. A pulse counter according to any one of claims 1 through 11, wherein:

the pulse wave extracting means extracts the pulse wave frequency using either a first extracting method in which the pulse frequency is extracted from the results of frequency analysis by the first calculating means, or a second extracting method in which the pulse frequency is extracted based on both the result of frequency analysis by the first calculating means and the result of frequency analysis by the second calculating means.

15. A pulse counter according to claim 14, wherein, when the SN condition detecting means determines that a noise component which will cause an error in the body motion pitch is included in the results of frequency analysis by the second calculating means, the pulse wave extracting means extracts the pulse wave frequency using the first extracting method.

16. A pulse display method characterized in the provision of:

a first calculating step for performing frequency analysis of a detected pulse wave signal;

a second calculating step for carrying out frequency analysis of a body motion signal detected by a body motion detecting means;

a pulse wave extracting step for extracting the frequency of the pulse based on the results of frequency analysis by the first and second calculating steps, and calculating the pulse rate;

a display step for displaying information including the pulse rate;

a SN condition detecting step for determining whether or not a noise component exceeding a specific value is included in at least one of either the result obtained from frequency analysis in the first calculating step or the result obtained from frequency analysis in the second calculating step; and

a display method switching steps for switching display contents in the display step in response to results detected by the SN condition detecting means.