Pulse rate counting device, pulse rate counting method, and record medium therefor

• US 8,777,866 B2
• Filed: 03/06/2009
• Issued: 07/15/2014
• Est. Priority Date: 03/06/2008
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Matsumoto, Chikako
• Primary Examiner(s): Natnithithadha, Navin
• Assistant Examiner(s): BLOCH, MICHAEL RYAN
• Application Number:
  US12/399,258
• Publication Number:
  US 20090227879A1
• Time in Patent Office: 1,957 Days
• Field of Search: 600500-503
• US Class Current: 600/500
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence

Abstract

A pulse rate counting device includes: a short-term average value calculation unit for calculating an average interval of predetermined previous pulses; a fluctuation amount calculation device for calculating the amount of fluctuation on the basis of the difference between the average interval and an actual pulse wave interval; a search range determination unit for calculating the width of the search range, calculating an amount of displacement on the basis of a time change of the average interval, and determining as a search range a range including an appearance prediction value of the next detection point calculated from the average interval and indicated by the width of the search range from a starting point determined on the basis of the amount of displacement; and a pulse wave interval detection unit for detecting the detection point in the determined search range, and outputting a pulse wave interval.

Claims

1. A pulse rate counting device, comprising:

a short-term average value calculation unit receiving input of pulse wave data acquired from a change of bloodstream and calculating an average interval of predetermined previous pulses;

a fluctuation value calculation unit calculating a fluctuation value that is an average of absolute values of differences between the average interval and a predetermined number of previous actual pulse wave intervals;

a search range determination unit calculating a width of a search range of a detection point as a reference of a next pulse wave interval by multiplying a previous pulse wave interval by the fluctuation value, calculating an amount of displacement on a basis of a time change of the average interval, and determining as a search range a range including an appearance prediction value of a next detection point calculated from the average interval and indicated by the width of a search range from a starting point that is a sum of the amount of displacement and the appearance prediction value; and

a pulse wave interval detection unit detecting the detection point in the determined search range, and outputting an interval between a predetermined detection point and a current detection point as a pulse wave interval.

2. The device according to claim 1, further comprising

a pulse wave interval correction unit correcting a detected pulse wave interval when a difference between a second average interval as an average for a longer time than a pulse wave on which the average interval is calculated and the detected pulse wave interval, or a difference between the average interval and the second average interval is larger than a threshold.

3. The device according to claim 1, further comprising

a pulse wave interval determination unit determining whether or not the pulse wave interval satisfies a predetermined condition.

4. The device according to claim 3, wherein

the search range determination unit determines a search range again when the pulse wave interval determination unit determines that the pulse wave interval does not satisfy a predetermined condition.

5. The device according to claim 3, further comprising

a reliability calculation unit calculating reliability of the pulse wave data on a basis of the fluctuation value or the pulse wave interval.

6. The device according to claim 3, further comprising

a physical activity status unit calculating a status of physical activity of a user on a basis of the fluctuation value or the pulse wave interval.

7. A pulse rate counting method, comprising:

receiving, using a computer, input of pulse wave data acquired from a change of bloodstream and calculating an average interval of predetermined previous pulses;

calculating, using the computer, a fluctuation value that is an average of absolute values of differences between the average interval and a predetermined number of previous actual pulse wave intervals;

calculating, using the computer, a width of a search range of a detection point as a reference of a next pulse wave interval by multiplying a previous pulse wave interval by the fluctuation value, calculating an amount of displacement on a basis of a time change of the average interval, and determining as a search range a range including an appearance prediction value of a next detection point calculated from the average interval and indicated by the width of the search range from a starting point that is a sum of the amount of displacement and the appearance prediction value; and

detecting, using the computer, the detection point in the determined search range, and outputting an interval between a predetermined detection point and a current detection point as a pulse wave interval.

8. The method according to claim 7, further comprising

correcting, using the computer, a detected pulse wave interval when a difference between a second average interval as an average for a longer time than a pulse wave on which the average interval is calculated and the detected pulse wave interval, or a difference between the average interval and the second average interval is larger than a threshold.

9. The method according to claim 7, further comprising

determining, using the computer, whether or not the pulse wave interval satisfies a predetermined condition.

10. The method according to claim 7, further comprising

determining, using the computer, a search range again when the pulse wave interval does not satisfy a predetermined condition.

11. A tangible non-transitory record medium containing computer executable instructions to perform a method, the method comprising:

receiving input of pulse wave data acquired from a change of bloodstream and calculating an average interval of predetermined previous pulses;

calculating a fluctuation value that is an average of absolute values of differences between the average interval and a predetermined number of previous actual pulse wave intervals;

calculating a width of a search range of a detection point as a reference of a next pulse wave interval by multiplying a previous pulse wave interval by the fluctuation value, calculating an amount of displacement on a basis of a time change of the average interval, and determining as a search range a range including an appearance prediction value of a next detection point calculated from the average interval and indicated by the width of a search range from a starting point that is a sum of the amount of displacement and the appearance prediction value; and

detecting the detection point in the determined search range, and outputting an interval between a predetermined detection point and a current detection point as a pulse wave interval.

12. The record medium according to claim 11, the method further comprising

correcting a detected pulse wave interval when a difference between a second average interval as an average for a longer time than a pulse wave on which the average interval is calculated and the detected pulse wave interval, or a difference between the average interval and the second average interval is larger than a threshold.

13. The record medium according to claim 11, further comprising the procedure of

determining whether or not the pulse wave interval satisfies a predetermined condition.

14. The record medium according to claim 13, the method further comprising

determining a search range again when the pulse wave interval does not satisfy a predetermined condition.