Motion compensating pulse rate monitor with motion sensor and level discriminator

• US 5,749,366 A
• Filed: 03/22/1996
• Issued: 05/12/1998
• Est. Priority Date: 03/23/1995
• Status: Expired due to Term

• Current Assignee: Seiko Instruments Incorporated (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group), Seiko Instruments Incorporated (Seiko Group)
• Inventors: Odagiri, Hiroyuki, Yasukawa, Naoaki
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): LAYNO, CARL HERNANDZ
• Application Number:
  US08/620,930
• Time in Patent Office: 781 Days
• Field of Search: 128/687, 128/689, 128/690, 128/696, 128/700, 128/714
• US Class Current: 600/502
• 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 5/02438 with portable devices, e.g. worn by the patient
• 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

Abstract

A pulse rate monitor allows a user'"'"'s pulse rate to be measured and displayed continuously while removing the inaccuracies caused by motion of the user, by detecting the motion level and determining whether an accurate pulse rate measurement can be taken based upon the detected motion. The most recent accurate pulse rate measurement is stored in memory and the pulse rate is estimated when a user is undergoing too much movement for obtaining accurate measurements by using the stored pulse rate and the magnitude of the detected movement.

Claims

1. A pulse rate monitor, comprising:

motion detecting means for detecting motion of a user using a motion sensor and for outputting an analog signal having a characteristic that varies in accordance with the magnitude of detected motion;

A/D converting means for converting the output analog signal of the motion detecting means into a digital signal;

motion level discriminating means for discriminating whether it is possible to accurately measure the user'"'"'s pulse based on the digital signal output from the A/D converting means and for outputting a control signal when a result of the discrimination indicates that accurate pulse measurement is possible;

pulse detecting means for detecting the user'"'"'s pulse and outputting a periodic signal corresponding to the detected pulse;

pulse rate calculating means for converting the periodic signal output from the pulse detecting means into pulse rate data;

pulse rate storing means for storing the pulse rate data output from the pulse rate calculating means in response to the control signal output from the motion level discriminating means;

display means for displaying the pulse rate data output from the pulse rate storing means; and

timing signal generating means for outputting a predetermined timing signal to the pulse rate calculating means and the display means.

2. A pulse rate monitor according to claim 1;

further comprising time counting means for counting the current time;

pulse detection controlling means for controlling the activation and deactivation of the pulse detecting means and the pulse rate calculating means depending upon the control signal output from the motion level discriminating means;

pulse rate storage controlling means for controlling the pulse rate storing means to store the pulse rate data output from the pulse rate calculating means and the time data of the time counting means when the output of the pulse detection controlling means permits pulse detection;

read out controlling means for providing an address used for reading out contents stored in the pulse rate storing means;

inputting means for controlling the read out controlling means at an arbitrary timing;

acceleration detection and A/D conversion controlling means for activating the motion detecting means and the A/D converting means intermittently at predetermined intervals;

wherein the display means includes means for displaying the time data of the time counting means and the timing signal generating means includes means for outputting the predetermined timing signal to the acceleration detection and A/D conversion controlling means and the time counting means.

3. A pulse rate monitor according to claim 2;

further comprising pattern storing means for storing a reference transition pattern of a predetermined pulse rate;

pattern comparing means for comparing a transition pattern of a measured pulse rate stored in the pulse rate storing means with the reference transition pattern stored in the pattern storing means; and

comparison result discriminating means for discriminating characteristics of the actually measured pulse rate transition pattern in accordance with a result of comparison performed by the pattern comparing means.

4. A pulse rate monitor according to claim 2;

further comprising motion level storing means for storing an output signal of the A/D converting means when an output of the motion level discriminating means indicates that it is impossible to accurately measure a pulse; and

pulse rate estimating means for estimating pulse rate data during the time that an accurate pulse rate cannot be measured based on the motion level data stored in the motion level storing means and the pulse rate data stored in the pulse rate storing means.

5. A pulse rate monitor comprising:

time counting means for counting the current time and producing time data;

motion detecting means for detecting motion using a motion sensor and outputting a corresponding analog signal;

A/D converting means for converting the analog signal of the motion detecting means into a digital signal;

motion level discriminating means for discriminating whether it is possible to accurately measure a pulse based on the digital signal output from the A/D converting means and for outputting a control signal corresponding to a result of the discrimination;

pulse detecting means for detecting a pulse from a living body and outputting a periodic signal corresponding to the detected pulse;

pulse rate calculating means for converting the periodic signal corresponding to the detected pulse output from the pulse detecting means into pulse rate data;

pulse detection controlling means for controlling the activation and deactivation of the pulse detecting means and the pulse data calculating means based on the control signal from the motion level discriminating means;

pulse rate storing means for storing pulse rate data output from the pulse rate calculating means and for storing corresponding time data of the time counting means;

pulse rate storage controlling means for controlling the pulse rate storing means to store the pulse rate data and the time data based on an output of the pulse detection controlling means;

read out controlling means for providing an address for reading out contents stored in the pulse rate storing means;

inputting means for controlling the read out controlling means with an arbitrary timing;

display means for displaying the data of the pulse rate storing means; and

timing signal generating means for outputting a predetermined timing signal to the pulse rate calculating means, the time counting means and the display means.

6. A pulse rate monitor according to claim 5;

further comprising motion detection and A/D conversion controlling means for activating the motion detecting means and the A/D converting means intermittently at predetermined intervals.

7. A pulse rate monitor according to claim 5;

further comprising pattern storing means for storing a reference transition pattern of a predetermined pulse rate;

pattern comparing means for comparing a transition pattern of a measured pulse rate stored in the pulse rate storing means with the reference transition pattern stored in the pattern storing means; and

comparison result discriminating means for discriminating characteristics of the measured pulse rate transition pattern in accordance with a result of the comparison performed by the pattern comparing means.

8. A pulse rate monitor according to claim 5;

further comprising motion level storing means for storing an output signal of the A/D converting means when an output of the motion level discriminating means indicates that it is not possible to accurately measure a pulse; and

pulse rate estimating means for estimating pulse rate data during the time that an accurate pulse cannot be measured based on the motion level data stored in the motion level storing means and the pulse rate data stored in the pulse rate storing means.

9. A pulse rate monitor for determining the pulse rate of a user, comprising:

motion detecting means for detecting motion of the user and outputting a movement signal having a characteristic that varies in accordance with the magnitude of the movement;

motion level discriminating means for determining whether it is possible to accurately measure the user'"'"'s pulse based upon the magnitude of the detected movement;

pulse rate measurement means for detecting the user'"'"'s pulse and calculating the user'"'"'s pulse rate; and

display means for displaying the calculated pulse rate.

10. A pulse rate monitor according to claim 9;

wherein the motion detecting means comprises an acceleration sensor and the motion level discriminating means comprises an A/D converter for converting an analog signal output by the motion sensor into a digital signal and a microprocessor for analyzing the digital signal and determining whether an accurate pulse measurement can be taken based upon the magnitude of the detected movement.

11. A pulse rate monitor according to claim 9;

wherein the pulse rate measurement means comprises means using a light emitting diode for projecting a light into the user'"'"'s body and a phototransistor for detecting light reflected from the user'"'"'s body and producing a pulse signal in accordance with the detected light, and a microprocessor for calculating the user'"'"'s pulse rate based upon the time difference between successively detected pulse signals.

12. A pulse rate monitor according to claim 9;

further comprising a memory for storing a pulse rate value measured when the motion level discriminating means has determined that the user'"'"'s pulse can accurately be measured.

13. A pulse rate monitor according to claim 9;

further comprising means for counting time; and

means for controlling the motion detecting means to intermittently detect motion of the user at predetermined intervals to reduce power consumption of the pulse rate monitor.

14. A pulse rate monitor according to claim 9;

further comprising means for deactivating the pulse rate measurement means when the motion level discriminating means has determined that the user'"'"'s pulse cannot be accurately measured.

15. A pulse rate monitor according to claim 9;

further comprising pattern storing means for storing a reference transition pattern of a predetermined pulse rate;

pattern comparing means for comparing a measured transition pattern of a pulse rate stored in the memory with the reference transition pattern stored in the pattern storing means; and

means for determining the characteristics of the measured pulse rate transition pattern based upon a result of the comparison.

16. A pulse rate monitor according to claim 9;

further comprising a memory for storing a most recent pulse rate value measured during a period when the motion level discriminating means has determined that the user'"'"'s pulse can be accurately measured;

storing means for storing the movement signal; and

pulse rate estimating means for estimating the user'"'"'s pulse rate during periods of time when the motion level discriminating means determines that the user'"'"'s pulse cannot be accurately measured based upon the movement signal and the most recent pulse rate value stored in the memory.

17. A pulse rate monitor comprising:

motion detecting means for detection motion of a user using a motion sensor and for outputting an analog signal having a characteristic that varies in accordance with the magnitude of detected motion;

A/D converting means for converting the output analog signal of the motion detecting means into a digital signal;

motion level discriminating means for discriminating whether it is possible to accurately measure the user'"'"'s pulse based on the digital signal output by the A/D converting means and for outputting a control signal when a result of the discrimination indicates that accurate pulse measurement is possible;

pulse detecting means for detecting the user'"'"'s pulse and outputting a periodic signal corresponding to the detected pulse;

pulse rate storing means for storing the pulse rate data output by the pulse rate calculating means in response to the control signal output by the motion level discriminating mean;

display means for displaying the pulse rate data output from the pulse rate storing means;

time counting means for counting current time and producing time data;

pulse detection controlling means for controlling the activation and deactivation of the pulse detecting means and the pulse rate calculating means depending upon the control signal output by the motion level discriminating means;

pulse rate storage controlling means for controlling the pulse rate storing means to store the pulse rate data output by the pulse rate calculating means and the time data of the time counting means when the output of the pulse detection controlling means permits pulse detection;

read out controlling means for providing an address used for reading out contents stored in the pulse rate storing means;

input means for controlling the read out controlling means at an arbitrary timing;

acceleration detection and A/D conversion controlling means for activating the motion detecting means and the A/D converting means intermittently at predetermined intervals;

display means for displaying the pulse rate data stored in the pulse rate storing means and the time data of the time counting means; and

timing signal generating means for outputting a predetermined timing signal to the pulse rate calculating means, the time counting means, the display means and the acceleration detection and A/D conversion controlling means.