PULSE RATE MEASURING APPARATUS

• US 20090287099A1
• Filed: 02/06/2009
• Published: 11/19/2009
• Est. Priority Date: 05/15/2008
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: MATSUMOTO, Chikako
• Granted Patent: US 8,551,007 B2
• Time in Patent Office: Days
• 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: G06F 2218/10 by analysing the shape of a waveform, e.g. extracting parameters relating to peaks

Abstract

From pulse wave data obtained from change in a blood flow, an average interval of a prescribed number of immediately preceding pulses or pulses in an immediately preceding prescribed time period is calculated. Next, an average-calculation range is determined on the basis of at least one of an amount of fluctuation and an evaluation result. The amount of fluctuation is a value calculated on the basis of a difference between the average interval and an interval of a pulse wave newly detected from the pulse wave data. The evaluation result is a result of evaluating the interval of the newly detected pulse wave by at least one evaluation factor. Thereafter, an average pulse wave interval value is calculated by averaging pulse wave intervals on the basis of the average-calculation range, and a pulse rate is calculated on the basis of the average pulse wave interval value.

Claims

1. A pulse rate measuring apparatus, comprising:

a first calculation device for receiving input of pulse wave data obtained from change in a blood flow, and calculating an average interval of a prescribed number of immediately preceding pulses or pulses in an immediately preceding prescribed time period;

a determination device for determining an average-calculation range for calculating an average value on the basis of at least one of an amount of fluctuation and an evaluation result, the amount of fluctuation being a value calculated on the basis of a difference between the average interval and an interval of a pulse wave newly detected from the pulse wave data, and the evaluation result being a result of evaluating the interval of the newly detected pulse wave by at least one evaluation factor;

a second calculation device for averaging pulse wave intervals of the pulse wave data on the basis of the average-calculation range, and calculating an average pulse wave interval value; and

a third calculation device for calculating a pulse rate on the basis of the average pulse wave interval value.

2. The pulse rate measuring apparatus according to claim 1, wherein:

when the amount of fluctuation is greater than a prescribed value, the determination device determines the average-calculation range to be relatively wider than an average-calculation range determined when the amount of fluctuation is smaller than the prescribed value.

3. The pulse rate measuring apparatus according to claim 1, wherein:

when the evaluation result is bad, the determination device determines the average-calculation range to be relatively wider than a range determined when the evaluation result is good.

4. The pulse rate measuring apparatus according to claim 3, wherein:

when a difference between the interval of the newly detected pulse wave and an interval of an immediately preceding pulse or the average interval is smaller than a prescribed value, the determination device determines the evaluation result to be better than an evaluation result determined when the difference is greater than the prescribed value.

5. The pulse rate measuring apparatus according to claim 3, wherein:

when a minimum value of one of the pulse wave data, difference data of the pulse wave data, and secondary difference data of the pulse wave data is smaller than a prescribed value, the determination device determines the evaluation result to be better than an evaluation result determined when the minimum value is greater than the prescribed value.

6. The pulse rate measuring apparatus according to claim 3, wherein:

when a maximum value of one of the pulse wave data, difference data of the pulse wave data, and secondary difference data of the pulse wave data is greater than a prescribed value, the determination device determines the evaluation result to be better than an evaluation result determined when the maximum value is smaller than the prescribed value.

7. The pulse rate measuring apparatus according to claim 3, wherein:

when an autocorrelation value of one of the pulse wave data, difference data of the pulse wave data, and secondary difference data of the pulse wave data is greater than a prescribed value, the determination device determines the evaluation result to be better than an evaluation result determined when the autocorrelation value is smaller than the prescribed value.

8. The pulse rate measuring apparatus according to claim 3, wherein:

when a difference ratio or a difference changing ratio between the interval of the newly detected pulse wave and an interval of a pulse wave in a normal state is smaller than a prescribed value, the determination device determines the evaluation result to be better than an evaluation result determined when the difference ratio or the difference changing ratio is greater than the prescribed value.

9. The pulse rate measuring apparatus according to claim 1, further comprising:

a correction device for correcting, when a difference between the pulse rate calculated by the third calculation device and a pulse rate calculated for an immediately preceding pulse is equal to or greater than a prescribed value, the pulse rate calculated by the third device using the pulse rate calculated for the immediately preceding pulse.

10. A storage medium storing a program causing a computer to execute:

receiving input of pulse wave data obtained from change in a blood flow, and calculating an average interval of a prescribed number of immediately preceding pulses or pulses in an immediately preceding prescribed time period;

determining an average-calculation range for calculating an average value on the basis of at least one of an amount of fluctuation and an evaluation result, the amount of fluctuation being a value calculated on the basis of a difference between the average interval and an interval of a pulse wave newly detected from the pulse wave data, and the evaluation result being a result of evaluating the interval of the newly detected pulse wave by at least one evaluation factor;

averaging pulse wave intervals of the pulse wave data on the basis of the average-calculation range, and calculating an average pulse wave interval value; and

calculating a pulse rate on the basis of the average pulse wave interval value.

11. A pulse rate measuring apparatus, comprising:

first calculation means for receiving input of pulse wave data obtained from change in a blood flow, and calculating an average interval of a prescribed number of immediately preceding pulses or pulses in an immediately preceding prescribed time period;

determination means for determining an average-calculation range for calculating an average value on the basis of at least one of an amount of fluctuation and an evaluation result, the amount of fluctuation being a value calculated on the basis of a difference between the average interval and an interval of a pulse wave newly detected from the pulse wave data, and the evaluation result being a result of evaluating the interval of the newly detected pulse wave by at least one evaluation factor;

second calculation means for averaging pulse wave intervals of the pulse wave data on the basis of the average-calculation range, and calculating an average pulse wave interval value; and

third calculation means for calculating a pulse rate on the basis of the average pulse wave interval value.