Pulse rate measuring apparatus

• US 8,551,007 B2
• Filed: 02/06/2009
• Issued: 10/08/2013
• Est. Priority Date: 05/15/2008
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Matsumoto, Chikako
• Primary Examiner(s): Blumel, Benjamin P
• Application Number:
  US12/367,251
• Publication Number:
  US 20090287099A1
• Time in Patent Office: 1,705 Days
• Field of Search: None
• 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 based on at least one of an amount of fluctuation and an evaluation result, the amount of fluctuation being a value calculated based on 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, wherein when the amount of fluctuation is greater than a prescribed value, the determination device determines the average-calculation range to be wider than the average-calculation range determined when the amount of fluctuation is smaller than the prescribed value;

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

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

2. The pulse rate measuring apparatus according to claim 1, 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 greater than a threshold value, the determination device determines the average-calculation range to be wider than a range determined when the difference is smaller than the threshold value.

3. The pulse rate measuring apparatus according to claim 1, 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 greater than a threshold value, the determination device determines the average-calculation range to be wider than a range determined when the minimum value is smaller than the threshold value.

4. The pulse rate measuring apparatus according to claim 1, 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 smaller than a threshold value, the determination device determines the average-calculation range to be wider than a range determined when the maximum value is greater than the threshold value.

5. The pulse rate measuring apparatus according to claim 1, 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 smaller than a threshold value, the determination device determines the average-calculation range to be wider than a range determined when the autocorrelation value is greater than the threshold value.

6. The pulse rate measuring apparatus according to claim 1, 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 greater than a threshold value, the determination device determines the average-calculation range to be wider than a range determined when the difference ratio or the difference changing ratio is smaller than the threshold value.

7. 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 threshold value, the pulse rate calculated by the third device using the pulse rate calculated for the immediately preceding pulse.

8. 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, wherein when the amount of fluctuation is greater than a prescribed value, the average-calculation range is determined to be wider than the average-calculation range determined when the amount of fluctuation is smaller than the prescribed value;

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.

9. 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.