Method, system and program product for analyzing pulse wave data

• US 20080249423A1
• Filed: 03/27/2008
• Published: 10/09/2008
• Est. Priority Date: 04/05/2007
• Status: Active Grant

• Current Assignee: Konica Minolta Sensing, Inc. (Konica Minolta Inc.)
• Original Assignee: Konica Minolta Sensing, Inc. (Konica Minolta Inc.)
• Inventors: Nagai, Yoshiroh, Kitajima, Kazumi
• Granted Patent: US 8,801,621 B2
• Time in Patent Office: Days
• US Class Current: 600/500
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

A pulse wave data analyzing method includes successively detecting bottom and top peak values of pulse wave data along a time axis, calculating successive bottom-to-top amplitude values along the time axis, and comparing first and second peak-to-peak amplitude values occurring in succession along the time axis. If the ratio of the second peak-to-peak amplitude value to the first peak-to-peak amplitude value is smaller than a preset threshold, the bottom and top peak values related to the second peak-to-peak amplitude value are classified as temporarily erased data. The second peak-to-peak amplitude value is compared with a third peak-to-peak amplitude value occurring immediately thereafter and, if the ratio between the second and third peak-to-peak amplitude values is larger than the threshold, the temporarily erased data is restored. If the ratio between the second and third peak-to-peak amplitude values is not larger than the threshold, the temporarily erased data is completely erased.

Claims

1. A pulse wave data analyzing method for extracting biometric information from pulse wave data taken from a living body, said pulse wave data analyzing method comprising the steps of:

successively detecting bottom peak values and top peak values of the pulse wave data obtained by continuously measuring a pulse wave for a specific period of time along a time axis;

combining two adjacent bottom and top peak values detected in succession along the time axis in pairs;

calculating a bottom-to-top amplitude value which is a difference between the bottom and top peak values of each successive pair along the time axis;

comparing a first peak-to-peak amplitude value and a second peak-to-peak amplitude value which correspond to two successive bottom-to-top amplitude values occurring in succession along the time axis;

classifying the bottom and top peak values related to the second peak-to-peak amplitude value as temporarily erased data if the ratio of the second peak-to-peak amplitude value to the first peak-to-peak amplitude value is smaller than a preset threshold;

comparing the second peak-to-peak amplitude value with a third peak-to-peak amplitude value which occurs in succession to the second peak-to-peak amplitude value;

restoring the temporarily erased bottom and top peak values related to the second peak-to-peak amplitude value as data to be used for pulse wave data analysis by canceling classification of the bottom and top peak values related to the second peak-to-peak amplitude value as the temporarily erased data if the ratio between the second and third peak-to-peak amplitude values is larger than the preset threshold; and

completely erasing the temporarily erased bottom and top peak values related to the second peak-to-peak amplitude value by regarding the bottom and top peak values as noise if the ratio between the second and third peak-to-peak amplitude values is not larger than the preset threshold.

2. The pulse wave data analyzing method according to claim 1 further comprising the step of calculating one of a top peak interval and a bottom peak interval equivalent to an RR interval observed on an electrocardiogram from the pulse wave data from which the noise has been removed.

3. The pulse wave data analyzing method according to claim 1 further comprising the step of calculating a bottom-to-top amplitude value from the pulse wave data from which the noise has been removed.

4. The pulse wave data analyzing method according to claim 1, further comprising, after classifying the bottom and top peak values related to the second peak-to-peak amplitude value as the temporarily erased data, the step of adopting a bottom-to-top amplitude value calculated from bottom and top peak values detected in succession to the temporarily erased bottom and top peak values along the time axis as a new second peak-to-peak amplitude value and comparing the second peak-to-peak amplitude value with the first peak-to-peak amplitude value at least once, and adopting this bottom-to-top amplitude value as the third peak-to-peak amplitude value when a bottom-to-top amplitude value not satisfying a condition for classifying bottom and top peak values related thereto as temporarily erased data occurs, and comparing at least one second peak-to-peak amplitude value related to the temporarily erased data with the third peak-to-peak amplitude value.

5. The pulse wave data analyzing method according to claim 4, wherein when there exist a plurality of second peak-to-peak amplitude values related to the temporarily erased data and classification of the bottom and top peak values related to one of the plural second peak-to-peak amplitude values is canceled as a result of a comparison with the third peak-to-peak amplitude value, said one of the plural second peak-to-peak amplitude values is adopted as the third peak-to-peak amplitude value and another one of the plural second peak-to-peak amplitude values is compared with the third peak-to-peak amplitude value thus adopted.

6. The pulse wave data analyzing method according to claim 4, wherein said threshold is altered at least once during execution of said operation for comparing the second peak-to-peak amplitude value with the first peak-to-peak amplitude value at least once.

7. A pulse wave data analyzing system for extracting biometric information from pulse wave data taken from a living body, said pulse wave data analyzing system comprising:

a pulse wave sensor for acquiring the pulse wave data varying along a time axis by measuring a pulse wave of a subject at specified sampling intervals; and

a data analyzer for analyzing the pulse wave data, said data analyzer including;

an inflection point detecting unit for successively detecting bottom and top peak values occurring along the time axis from the pulse wave data;

an amplitude detecting unit for combining two adjacent bottom and top peak values occurring in succession along the time axis in pairs and calculating a bottom-to-top amplitude value which is a difference between the bottom and top peak values of each successive pair along the time axis;

a temporary erasure unit for comparing a first peak-to-peak amplitude value and a second peak-to-peak amplitude value which correspond to two successive bottom-to-top amplitude values occurring in succession along the time axis and classifying the bottom and top peak values related to the second peak-to-peak amplitude value as temporarily erased data if the ratio of the second peak-to-peak amplitude value to the first peak-to-peak amplitude value is smaller than a preset threshold;

a noise filtration unit for comparing the second peak-to-peak amplitude value with a third peak-to-peak amplitude value which occurs in succession to the second peak-to-peak amplitude value, restoring the temporarily erased bottom and top peak values related to the second peak-to-peak amplitude value by canceling classification of the bottom and top peak values related to the second peak-to-peak amplitude value as the temporarily erased data if the ratio between the second and third peak-to-peak amplitude values is larger than the preset threshold, and completely erasing the temporarily erased bottom and top peak values related to the second peak-to-peak amplitude value by regarding the bottom and top peak values as noise if the ratio between the second and third peak-to-peak amplitude values is not larger than the preset threshold.

8. The pulse wave data analyzing system according to claim 7, further comprising a display unit for displaying results of pulse wave data analysis obtained by said data analyzer, wherein said pulse wave sensor, said data analyzer and said display unit are built in a device which can be worn by the subject.

9. The pulse wave data analyzing system according to claim 7, further comprising:

a third storage unit for storing the pulse wave data acquired by said data analyzer;

wherein said pulse wave data analyzing system is divided into a first device including said pulse wave sensor and said third storage unit, said first device being configured to be wearable by the subject, and a second device including said data analyzer, said second device being configured to have capability to take in the pulse wave data stored in said third storage unit by conducting data communication with said first device.

10. The pulse wave data analyzing system according to claim 7 further comprising:

a first storage unit for storing the bottom and top peak values detected by said inflection point detecting unit; and

a second storage unit capable of storing data at least temporarily;

wherein said temporary erasure unit transfers the bottom and top peak values classified as the temporarily erased data from said first storage unit to said second storage unit when such bottom and top peak values occur, and said noise filtration unit transfers the bottom and top peak values once classified as the temporarily erased data from said second storage unit back to said first storage unit when canceling classification of the bottom and top peak values as the temporarily erased data.

11. The pulse wave data analyzing system according to claim 10, further comprising a display unit for displaying results of pulse wave data analysis obtained by said data analyzer, wherein said pulse wave sensor, said data analyzer and said display unit are built in a device which can be worn by the subject.

12. The pulse wave data analyzing system according to claim 10, further comprising:

a third storage unit for storing the pulse wave data acquired by said data analyzer;

wherein said pulse wave data analyzing system is divided into a first device including said pulse wave sensor and said third storage unit, said first device being configured to be wearable by the subject, and a second device including said data analyzer, said second device being configured to have capability to take in the pulse wave data stored in said third storage unit by conducting data communication with said first device.

13. The pulse wave data analyzing system according to claim 7, wherein said temporary erasure unit assigns a temporary erasure identifier to the bottom and top peak values classified as the temporarily erased data when such bottom and top peak values occur, and said noise filtration unit removes the temporary erasure identifier from the bottom and top peak values classified as the temporarily erased data when canceling classification of the bottom and top peak values as the temporarily erased data and erases the bottom and top peak values assigned with the temporary erasure identifier when completely erasing these bottom and top peak values.

14. The pulse wave data analyzing system according to claim 13, further comprising a display unit for displaying results of pulse wave data analysis obtained by said data analyzer, wherein said pulse wave sensor, said data analyzer and said display unit are built in a device which can be worn by the subject.

15. The pulse wave data analyzing system according to claim 13, further comprising:

a third storage unit for storing the pulse wave data acquired by said data analyzer;

wherein said pulse wave data analyzing system is divided into a first device including said pulse wave sensor and said third storage unit, said first device being configured to be wearable by the subject, and a second device including said data analyzer, said second device being configured to have capability to take in the pulse wave data stored in said third storage unit by conducting data communication with said first device.

16. The pulse wave data analyzing system according to claim 7, wherein said data analyzer analyses the pulse wave data in real time and displays pulse wave information obtained as a result of pulse wave data analysis on a display screen.

17. The pulse wave data analyzing system according to claim 7 further comprising a fourth storage unit for storing the pulse wave information obtained by said data analyzer as a result of pulse wave data analysis.

18. An analyzing program product for extracting biometric information from pulse wave data taken from a living body, said analyzing program product comprising:

a recording medium; and

a pulse wave data analyzing program recorded on said recording medium, wherein said pulse wave data analyzing program causes a data analyzer for analyzing the pulse wave data to;

read out the pulse wave data varying along a time axis acquired by measuring a pulse wave of a subject at specified sampling intervals;

successively detect bottom peak values and top peak values of the pulse wave data;

combine two adjacent bottom and top peak values detected in succession along the time axis in pairs;

calculate a bottom-to-top amplitude value which is a difference between the bottom and top peak values of each successive pair along the time axis;

compare a first peak-to-peak amplitude value and a second peak-to-peak amplitude value which correspond to two successive bottom-to-top amplitude values occurring in succession along the time axis;

classify the bottom and top peak values related to the second peak-to-peak amplitude value as temporarily erased data if the ratio of the second peak-to-peak amplitude value to the first peak-to-peak amplitude value is smaller than a preset threshold;

compare the second peak-to-peak amplitude value with a third peak-to-peak amplitude value which occurs in succession to the second peak-to-peak amplitude value;

restore the temporarily erased bottom and top peak values related to the second peak-to-peak amplitude value as data to be used for pulse wave data analysis by canceling classification of the bottom and top peak values related to the second peak-to-peak amplitude value as the temporarily erased data if the ratio between the second and third peak-to-peak amplitude values is larger than the preset threshold;

completely erase the temporarily erased bottom and top peak values related to the second peak-to-peak amplitude value by regarding the bottom and top peak values as noise if the ratio between the second and third peak-to-peak amplitude values is not larger than the preset threshold; and

perform specific pulse wave analysis on the pulse wave data from which the noise has been removed.