Heart rate information acquisition device, heart rate information acquisition method, and body movement detection device

Abstract

This invention provides a heart rate information acquisition device that can select the appropriate signal from multiple signals to obtain highly accurate heart rate information. [Solution] A heart rate information acquisition device for acquiring heart rate information of a subject lying in bed comprises: a signal acquisition unit that acquires a plurality of signals, each containing a component that fluctuates according to the subject's heart rate; a signal selection unit that selects an information acquisition signal from the plurality of signals to be used for acquiring the heart rate information based on the kurtosis of each of the plurality of signals; and a heart rate information acquisition unit that acquires the subject's heart rate information based on the information acquisition signal.

Claims

1. A heart rate information acquisition device that acquires heart rate information of a subject lying in bed, A signal acquisition unit that acquires multiple signals, each containing a component that fluctuates according to the heart rate of the subject, A signal selection unit selects an information acquisition signal from the plurality of signals to be used for acquiring the heart rate information based on the kurtosis of each of the plurality of signals. A heart rate information acquisition device comprising a heart rate information acquisition unit that acquires heart rate information of the subject based on the information acquisition signal.

2. The system further includes a noise determination unit that determines the amount of noise contained in each of the plurality of signals based on the frequency analysis of each of the plurality of signals, The heart rate information acquisition device according to claim 1, wherein the signal selection unit selects the information acquisition signal from the signal determined to have a low amount of noise based on the kurtosis of the signal among the plurality of signals that is determined to have a low amount of noise.

3. The noise determination unit determines the amount of noise in the target signal, which is one of the plurality of signals. Based on the aforementioned target signal, an estimated value of the subject's average heart rate interval is calculated, The frequency spectrum is obtained by applying a Fourier transform to the aforementioned target signal. In the acquired frequency spectrum, the ratio is obtained between the sum of the intensities of multiple positions separated in the frequency direction by a distance corresponding to the estimated average heart rate interval, and the sum of the amplitudes of multiple positions shifted in the frequency direction from those multiple positions. The heart rate information acquisition device according to claim 2, which is performed by comparing the ratio with a threshold.

4. The noise determination unit determines whether or not phase inversion of the target signal is necessary based on a comparison between the standard deviation of the target signal in the region where the amplitude of the target signal is greater than the average value of the amplitude of the target signal and the standard deviation of the target signal in the region where the amplitude of the target signal is smaller than the average value of the amplitude of the target signal. The heart rate information acquisition device according to claim 3, which calculates an estimated value of the average heart rate interval of the subject based on the detection of the peak of the target signal after phase inversion.

5. The heart rate information acquisition device according to any one of claims 1 to 4, further comprising a noise reduction unit that, when the signal selection unit selects two or more signals as the information acquisition signal, generates a single information acquisition signal from the two or more signals with reduced noise by principal component analysis.

6. The heart rate information acquisition device according to any one of claims 1 to 5, wherein the signal selection unit calculates a plurality of kurtosis values ​​corresponding to a plurality of periods for at least one of the plurality of signals, and sets the median value of the plurality of kurtosis values ​​as the kurtosis of the signal.

7. The heart rate information acquisition device according to any one of claims 1 to 6, wherein the signal acquisition unit applies frequency filtering to each of the plurality of signals.

8. The heart rate information acquisition device according to any one of claims 1 to 7, wherein the signal acquisition unit normalizes each of the plurality of signals.

9. The system further includes a body movement determination unit that determines whether or not body movement is occurring in the subject based on a comparison between the minimum value of a plurality of standard deviations calculated for each of the plurality of normalized signals or a plurality of signals obtained by time-dividing any one of the plurality of normalized signals, and a threshold value. The heart rate information acquisition device according to claim 8, wherein if the body movement determination unit determines that the subject is moving, the device does not acquire the heart rate information based on the signal for the period during which the subject is determined to be moving.

10. The signal acquisition unit acquires at least one composite signal, each of which is obtained by adding up two of the plurality of signals. The heart rate information acquisition device according to any one of claims 1 to 9, wherein the signal selection unit selects the information acquisition signal from the plurality of signals and the at least one composite signal based on the kurtosis of each of the plurality of signals and the at least one composite signal.

11. The heart rate information acquisition device according to any one of claims 1 to 10, wherein the signal acquisition unit separates signals by performing component analysis on at least one of the plurality of signals, and identifies a heart rate component from the separated signals.

12. The heart rate information acquisition device according to any one of claims 1 to 11, wherein the signal acquisition unit inverts the phase of at least one of the plurality of signals.

13. The aforementioned heart rate information acquisition unit is The characteristic quantities relating to the peak waveform of the aforementioned information acquisition signal are extracted, Based on the classification of the aforementioned features, a peak corresponding to the subject's heart rate is identified from the peaks of the information acquisition signal. A heart rate information acquisition device according to any one of claims 1 to 12, which acquires heart rate information based on the identified peak.

14. The heart rate information acquisition device according to any one of claims 1 to 13, wherein the heart rate information acquisition unit acquires the heart rate information based on matching a template generated based on the peak of the information acquisition signal with the information acquisition signal.

15. The heart rate information acquisition device according to claim 14, wherein the heart rate information acquisition unit acquires the heart rate information based on the peak of the correlation function between the template and the information acquisition signal.

16. The heart rate information acquisition device according to any one of claims 1 to 15, wherein the heart rate information acquisition unit extracts a section to be analyzed from the information acquisition signal and acquires the heart rate information by estimating the interval between the appearance of similar waveforms.

17. The aforementioned heart rate information acquisition unit is Multiple correlation indices are calculated to estimate the interval between the appearance of the aforementioned similar waveforms. The heart rate information acquisition device according to claim 16, which acquires heart rate information by calculating the probability that the estimated occurrence interval represents a heart rate interval based on the calculated plurality of correlation indicators.

18. The heart rate information acquisition device according to claim 17, wherein the heart rate information acquisition unit performs the estimation of the occurrence interval of similar waveforms again for intervals in which the estimated occurrence interval is lower than a set threshold in which the probability of representing a heart rate interval is lower.

19. A method for acquiring heart rate information of a subject lying in bed, The signal acquisition unit acquires multiple signals, each containing a component that varies according to the subject's heart rate, The signal selection unit selects an information acquisition signal from the plurality of signals to be used for acquiring the heart rate information based on the kurtosis of each of the plurality of signals, A method for acquiring heart rate information, which includes acquiring the heart rate information of the subject based on the information acquisition signal using a heart rate information acquisition unit.

20. A body movement determination device comprising: a body movement determination unit that determines whether or not body movement is occurring in a subject based on a comparison between the minimum value of a plurality of standard deviations calculated for a plurality of signals, each containing a component that fluctuates in accordance with the body movement of the subject on the bed and which have been normalized, and a threshold value.

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