Biological information detection system, biological information detection method, and program

Abstract

To provide a biological information detection system, a biological information detection method, and a program capable of measuring biological information such as a respiratory frequency and a cardiac rate of a person to be measured with a high degree of precision.SOLUTION: A Doppler data acquisition unit 20 acquires Doppler data indicating a measurement result by a Doppler sensor in a certain period for each of a plurality of Doppler sensors provided toward a person to be measured. A frequency spectrum generation unit 22 generates a frequency spectrum on the basis of the Doppler data indicating a measurement result by the Doppler sensor for each of the plurality of Doppler sensors. A consolidation spectrum generation unit 26 generates a consolidation spectrum on the basis of a part or all of the frequency spectra generated for each of the plurality of Doppler sensors. A biological information generation unit 28 generates biological information on the person to be measured in the period on the basis of the consolidation spectrum.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a biological information detection system, a biological information detection method, and a program, and particularly to a system for detecting biological information of a subject based on a Doppler signal.

Background Art

[0002] Various systems for measuring biological information such as the breathing rate and heart rate of a subject have been studied. As an example of such a system, Patent Document 1 describes a monitoring device that determines the breathing rate and heart rate non-contact by a microwave Doppler sensor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to improve the accuracy of the measurement result of the biological information (here, for example, the breathing rate or heart rate) of the subject, the inventor is considering measuring the biological information using a plurality of Doppler sensors.

[0005] When measuring the biological information of the subject using a plurality of Doppler sensors, due to the position and posture of the subject, etc., among the measurement results obtained from each of these plurality of Doppler sensors, there may be those with low accuracy.

[0006] Therefore, when measuring the biological information with each of these plurality of Doppler sensors and using a representative value such as the average value of the measured biological information as the value of the biological information of the subject, the value of the biological information obtained in this way may not be a reasonable value.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a biological information detection system, a biological information detection method, and a program capable of accurately measuring biological information such as the respiration rate and heart rate of a subject.

Means for Solving the Problems

[0008] (1) The biological information detection system according to the present invention includes Doppler data acquisition means for acquiring Doppler data indicating measurement results by each of a plurality of Doppler sensors provided facing a subject, for each of the plurality of Doppler sensors, frequency spectrum generation means for generating a frequency spectrum based on the Doppler data indicating the measurement results by the Doppler sensor, for each of the plurality of Doppler sensors, aggregation spectrum generation means for generating an aggregation spectrum based on a part or all of the frequency spectra generated for each of the plurality of Doppler sensors, and biological information generation means for generating biological information of the subject during the period based on the aggregation spectrum.

[0009] (2) In the biological information detection system according to (1), selection means for selecting a plurality from among the frequency spectra generated for each of the plurality of Doppler sensors based on the peak frequencies in the frequency spectra generated for each of the plurality of Doppler sensors is further included, and the aggregation spectrum generation means may generate the aggregation spectrum based on the plurality of selected frequency spectra.

[0010] (3) In the biological information detection system according to (1) or (2), the aggregation spectrum generation means may generate the aggregation spectrum, which is a frequency spectrum obtained by summing or averaging a part or all of the frequency spectra generated for each of the plurality of Doppler sensors.

[0011] (4) In the biological information detection system according to any one of (1) to (3), the biological information generation means may generate the biological information of the subject during the period based on the peak frequency in the aggregated spectrum.

[0012] (5) The biological information detection method according to the present invention includes steps of: for each of a plurality of Doppler sensors provided facing a subject, acquiring Doppler data indicating a measurement result by the Doppler sensor during a certain period; for each of the plurality of Doppler sensors, generating a frequency spectrum based on the Doppler data indicating the measurement result by the Doppler sensor; generating an aggregated spectrum based on a part or all of the frequency spectra generated for each of the plurality of Doppler sensors; and generating the biological information of the subject during the period based on the aggregated spectrum.

[0013] (6) The program according to the present invention is a program for causing a computer to execute steps of: for each of a plurality of Doppler sensors provided facing a subject, acquiring Doppler data indicating a measurement result by the Doppler sensor during a certain period; for each of the plurality of Doppler sensors, generating a frequency spectrum based on the Doppler data indicating the measurement result by the Doppler sensor; generating an aggregated spectrum based on a part or all of the frequency spectra generated for each of the plurality of Doppler sensors; and generating the biological information of the subject during the period based on the aggregated spectrum. This program may be stored in a computer-readable information storage medium.

Effect of the Invention

[0014] According to the present invention, biological information such as the respiration rate and heart rate of a subject can be accurately measured.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0017] FIG. 1 is a configuration diagram of a biological information detection system 1 according to an embodiment of the present invention. As shown in the figure, the biological information detection system 1 includes a signal processing device 10 and a Doppler sensor unit 12. The Doppler sensor unit 12 includes a plurality of Doppler sensors 16 (see FIG. 2). Here, for example, it is assumed that the Doppler sensor unit 12 includes six Doppler sensors 16 (16a to 16f). As shown in FIG. 1, the Doppler sensor unit 12 is provided facing the subject to be measured.

[0018] Also, in the example of FIG. 1, the Doppler sensor unit 12 is attached to the headboard of the bed 14. Here, the plurality of Doppler sensors 16 may be provided symmetrically with respect to the center line of the bed 14 (a line passing through the center in the width direction of the bed 14 and extending in the length direction of the bed 14). Also, the plurality of Doppler sensors 16 may be arranged side by side perpendicular to the length direction of the bed 14 (the direction along the center line of the bed 14). Also, the plurality of Doppler sensors 16 may be arranged in a row at equal intervals.

[0019] All Doppler sensors 16 are provided so as to face the length direction (longitudinal direction) of the bed 14, and emit microwaves in the length direction of the bed 14. The microwaves are reflected by the chest of the subject sleeping on the bed 14, and each Doppler sensor 16 receives the reflected wave. Each Doppler sensor 16 generates a Doppler signal indicating the movement of the chest associated with breathing from the reflected wave, and outputs Doppler data obtained by digitizing this Doppler signal. Note that the microwaves emitted from each Doppler sensor 16 have slightly shifted frequencies, thereby preventing mutual interference.

[0020] Due to the Doppler effect, the reflected wave has a frequency shift, and by observing this, the respiratory rate of the subject can be obtained. The reflected wave is detected as a Doppler signal including an I signal that is in-phase component with the transmitted wave and a Q signal that is the quadrature component by quadrature detection, and is output to the signal processing device 10 in digital form. The Doppler signal input to the signal processing device 10 is time-series data, indicating the amplitudes (I component and Q component) at each time.

[0021] The signal processing device 10 may be configured by a known computer including, for example, a CPU, a memory, an input device, and a display, and generates the respiratory rate of the subject based on the Doppler signal output from the Doppler sensor 16.

[0022] FIG. 2 is a functional block diagram of the signal processing device 10 according to an embodiment of the present invention. As shown in the figure, the signal processing device 10 includes a Doppler data acquisition unit 20, a frequency spectrum generation unit 22, a frequency spectrum selection unit 24, an aggregated spectrum generation unit 26, and a biological information generation unit 28. These functional blocks are realized by executing a signal processing program in the signal processing device 10 which is a computer. This signal processing program may be stored in various computer-readable information storage media such as a semiconductor memory, and loaded from the medium into the signal processing device 10. Alternatively, it may be downloaded to the signal processing device 10 via a data communication line such as the Internet.

[0023] The Doppler data acquisition unit 20 acquires Doppler data indicating the measurement results by the Doppler sensor 16 during a certain period for each of the plurality of Doppler sensors 16 provided facing the subject to be measured.

[0024] For example, as shown in FIG. 3, the Doppler data acquisition unit 20 cuts out a part indicating the measurement results in the corresponding period from the Doppler data indicating the measurement results by the Doppler sensor 16 for each of the plurality of Doppler sensors 16 for each of the plurality of periods (a plurality of time windows).

[0025] For example, from the first Doppler data acquired from the Doppler sensor 16a, Doppler data D(1,1), D(2,1), D(3,1), D(4,1),... indicating the measurement results in the first time window, the second time window, the third time window, the fourth time window,... are cut out. Also, from the second Doppler data acquired from the Doppler sensor 16b, Doppler data D(1,2), D(2,2), D(3,2), D(4,2),... indicating the measurement results in the first time window, the second time window, the third time window, the fourth time window,... are cut out.

[0026] Similarly, for Doppler sensors 16c to 16f, Doppler data indicating the measurement results in each time window is cut out. For example, from the third Doppler data obtained from Doppler sensor 16c, Doppler data D(1,3), D(2,3), D(3,3), D(4,3),... indicating the measurement results in the first time window, the second time window, the third time window, the fourth time window,... is cut out. Also, from the fourth Doppler data obtained from Doppler sensor 16d, Doppler data D(1,4), D(2,4), D(3,4), D(4,4),... indicating the measurement results in the first time window, the second time window, the third time window, the fourth time window,... is cut out. Also, from the fifth Doppler data obtained from Doppler sensor 16e, Doppler data D(1,5), D(2,5), D(3,5), D(4,5),... indicating the measurement results in the first time window, the second time window, the third time window, the fourth time window,... is cut out. Also, from the sixth Doppler data obtained from Doppler sensor 16f, Doppler data D(1,6), D(2,6), D(3,6), D(4,6),... indicating the measurement results in the first time window, the second time window, the third time window, the fourth time window,... is cut out.

[0027] The length of each time window is constant (for example, 60 seconds), and the start timing of each time window is shifted by a predetermined time (here, for example, 2 seconds). Also, the time windows applied to any of the first to sixth Doppler data are common. That is, for any of the first to sixth Doppler data, for example, the period corresponding to the first time window is the same period, and the period corresponding to the second time window is also the same period.

[0028] The frequency spectrum generation unit 22 generates a frequency spectrum, for example, for each of the plurality of Doppler sensors 16, based on the Doppler data indicating the measurement results by the Doppler sensor 16.

[0029] The frequency spectrum generation unit 22 converts the input Doppler data into a frequency spectrum by, for example, performing a fast Fourier transform (FFT) or the like on the input Doppler data. Here, for example, the data of the I signal and the data of the Q signal may each be converted into a frequency spectrum.

[0030] The frequency spectrum selection unit 24 selects a plurality from among the frequency spectra generated for each of the plurality of Doppler sensors 16, for example, based on the peak frequencies in the frequency spectra generated for each of the plurality of Doppler sensors 16.

[0031] Here, an example of the flow of the frequency spectrum selection process performed by the frequency spectrum selection unit 24 will be described with reference to the flowchart illustrated in FIG. 4. Here, for example, the process of selecting a plurality from among the frequency spectra generated for the data of the I signal and the data of the Q signal of each of the six Doppler data D(1,1), D(1,2), D(1,3), D(1,4), D(1,5), D(1,6) cut out for the first time window will be described.

[0032] First, the frequency spectrum selection unit 24 specifies, as the respiration rate corresponding to the frequency spectrum, the peak frequency that is the frequency of the maximum amplitude in the frequency spectrum generated for the data of the I signal and the data of the Q signal of each of the six Doppler data D(1,1), D(1,2), D(1,3), D(1,4), D(1,5), D(1,6)) (S101).

[0033] Then, the frequency spectrum selection unit 24 calculates a representative value (here, for example, the average value) of the respiration rate specified in the process shown in S101 (S102).

[0034] Then, the frequency spectrum selection unit 24 checks whether there is a frequency spectrum corresponding to a respiration rate (that is, a respiration rate that is an outlier) whose difference from the representative value calculated in the process shown in S102 is equal to or greater than a predetermined value (for example, 5) (S103).

[0035] When there is a respiration rate that is an outlier (S103: Y), the frequency spectrum selection unit 24 excludes the frequency spectrum corresponding to the respiration rate that is an outlier (S104), and returns to the process shown in S102.

[0036] When there is no respiration rate that is an outlier (S103: N), the process shown in this processing example ends. In the process shown in this processing example, all frequency spectra may be selected without any frequency spectrum being excluded.

[0037] The frequency spectrum remaining without being excluded in the above process corresponds to the frequency spectrum selected from among the frequency spectra generated for the data of the I signal and the data of the Q signal of each of the six Doppler data cut out for the first time window. The process described above is executed for each of a plurality of time windows.

[0038] The aggregated spectrum generation unit 26 generates an aggregated spectrum based on, for example, some or all of the frequency spectra generated for each of the plurality of Doppler sensors 16. As shown in FIG. 5, regarding the first time window, the frequency spectrum of the data of the I signal of D(1,1), the frequency spectrum of the data of the Q signal of D(1,1), the frequency spectrum of the data of the I signal of D(1,2), the frequency spectrum of the data of the Q signal of D(1,2), the frequency spectrum of the data of the I signal of D(1,3), the frequency spectrum of the data of the Q signal of D(1,3), ···, the amplitude (intensity) in the frequency spectrum of the data of the Q signal of D(1,6) is added for each frequency, and an aggregated spectrum (1) may be generated. The aggregated spectrum (1) corresponds to the aggregated spectrum of the first time window. In this way, the aggregated spectrum generation unit 26 may generate an aggregated spectrum that is a frequency spectrum obtained by summing some or all of the frequency spectra generated for each of the plurality of Doppler sensors 16.

[0039] Further, the aggregated spectrum generation unit 26 may generate an aggregated spectrum, which is a frequency spectrum obtained by averaging some or all of the frequency spectra generated for each of the plurality of Doppler sensors 16.

[0040] Alternatively, the aggregated spectrum generation unit 26 may generate an aggregated spectrum based on a plurality of frequency spectra selected by the frequency spectrum selection unit 24. For example, assume that the frequency spectra of the I-signal data of D(1,5), the frequency spectra of the Q-signal data of D(1,5), the frequency spectra of the I-signal data of D(1,6), and the frequency spectra of the Q-signal data of D(1,6) are excluded, and other frequency spectra are selected. In this case, an aggregated spectrum (1), which is a frequency spectrum obtained by summing the frequency spectra of the I-signal data of D(1,1), the frequency spectra of the Q-signal data of D(1,1), the frequency spectra of the I-signal data of D(1,2), the frequency spectra of the Q-signal data of D(1,2), the frequency spectra of the I-signal data of D(1,3), the frequency spectra of the Q-signal data of D(1,3), the frequency spectra of the I-signal data of D(1,4), and the frequency spectra of the Q-signal data of D(1,4), may be generated. By doing so, the influence of outliers in the generated aggregated spectrum can be suppressed.

[0041] In FIG. 5, an aggregated spectrum (1), which is the aggregated spectrum of the first time window, is shown. Similarly, an aggregated spectrum (2), which is the aggregated spectrum of the second time window, an aggregated spectrum (3), which is the aggregated spectrum of the third time window, and so on are generated.

[0042] The biological information generation unit 28 generates the biological information of the subject during the period based on the aggregated spectrum, for example. Here, the biological information generation unit 28 may generate the respiration rate of the subject during the period based on the peak frequency in the aggregated spectrum. For example, the frequency of the maximum amplitude in the aggregated spectrum may be specified as the peak frequency. Then, the peak frequency in the aggregated spectrum may be generated as the respiration rate.

[0043] Further, the biological information generation unit 28 may specify the maximum amplitude and the second largest amplitude in the aggregated spectrum. Then, the biological information generation unit 28 may generate an amplitude ratio obtained by dividing the maximum amplitude by the second largest amplitude.

[0044] Further, the biological information generation unit 28 may generate an amplitude ratio for each of the aggregated spectra calculated for a plurality of time windows (for example, from the first time window to the 30th time window). Then, the biological information generation unit 28 may extract an aggregated spectrum whose amplitude ratio is equal to or greater than a predetermined threshold (for example, 1.5). Then, the biological information generation unit 28 may generate, as the respiration rate in a period (for example, one minute) associated with the plurality of time windows, the average value of the respiration rates generated for each of the aggregated spectra whose amplitude ratio is equal to or greater than a predetermined threshold (for example, 1.5).

[0045] Further, the biological information generation unit 28 may generate, as a reliability, the ratio of the number of aggregated spectra whose amplitude ratio is equal to or greater than a predetermined threshold (for example, 1.5) to the number of aggregated spectra calculated for a plurality of time windows.

[0046] Note that, in the present embodiment, the frequency spectrum selection unit 24 may not select the frequency spectrum. Then, the aggregated spectrum generation unit 26 may generate an aggregated spectrum for a certain period using all the frequency spectra generated by the frequency spectrum generation unit 22 for the certain period.

[0047] Further, the frequency spectrum selection unit 24 may select the frequency spectrum for each Doppler sensor 16. That is, the frequency spectrum selection unit 24 may select a plurality of the plurality of Doppler sensors 16 based on the peak frequencies in the frequency spectra generated for each of the plurality of Doppler sensors 16. Then, the aggregated spectrum generation unit 26 may generate an aggregated spectrum based on the frequency spectra generated for each of the selected plurality of Doppler sensors 16.

[0048] Also, it is not necessary for the data of the I signal and the data of the Q signal to be respectively converted into the frequency spectrum. For example, the data of the complex signal with the I component as the real part and the Q component as the imaginary part may be converted into the frequency spectrum. And an aggregated spectrum may be generated based on the frequency spectrum.

[0049] When measuring the biological information of the subject using a plurality of Doppler sensors 16, due to the position and posture of the subject, etc., among the measurement results obtained from each of these plurality of Doppler sensors 16, there may be those with low accuracy.

[0050] Therefore, when measuring the biological information with each of these plurality of Doppler sensors 16 and using a representative value such as the average value of the measured biological information as the value of the biological information of the subject, the value of the biological information obtained in this way may not be a reasonable value.

[0051] In this embodiment, as described above, biological information is generated based on the aggregated spectrum. Therefore, according to this embodiment, compared with the case of using a representative value such as the average value of the measured biological information as the value of the biological information of the subject, it is possible to accurately measure the biological information of the subject.

[0052] Also, for example, since each Doppler sensor 16 has a different angle with respect to the subject, there may be a slight difference in the peak frequency of the frequency spectrum based on the measurement result. Here, when adopting arrangements such as an arrangement where a plurality of Doppler sensors 16 are arranged side by side perpendicular to the length direction of the bed 14, an arrangement where a plurality of Doppler sensors 16 are arranged symmetrically with respect to the center line of the bed 14, an arrangement where a plurality of Doppler sensors 16 are arranged in a row at equal intervals, etc., an aggregated spectrum that appropriately equalizes the frequency spectra corresponding to each Doppler sensor 16 will be generated, and as a result, it becomes possible to more accurately measure the biological information of the subject.

[0053] Note that the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, in the above description, the respiration rate is generated as the biological information of the subject to be measured, but the heart rate can also be generated in the same manner.

Explanation of Signs

[0054] 1 Biological information detection system, 10 Signal processing device, 12 Doppler sensor unit, 14 Bed, 16, 16a, 16b, 16c, 16d, 16e, 16f Doppler sensor, 20 Doppler data acquisition unit, 22 Frequency spectrum generation unit, 24 Frequency spectrum selection unit, 26 Aggregated spectrum generation unit, 28 Biological information generation unit.

Claims

1. a Doppler data acquisition means for acquiring, for each of a plurality of Doppler sensors provided facing the subject, Doppler data indicating a measurement result by the Doppler sensor during a certain period of time; a frequency spectrum generating means for generating a frequency spectrum for each of the plurality of Doppler sensors based on the Doppler data indicating a measurement result by the corresponding Doppler sensor; an aggregate spectrum generating means for generating an aggregate spectrum based on a part or all of the frequency spectra generated for each of the plurality of Doppler sensors; a biological information generating means for generating biological information of the subject for the period based on the aggregate spectrum; A biological information detection system comprising:

2. 2. The biological information detection system according to claim 1, a selection unit that selects a plurality of the frequency spectra generated for each of the plurality of Doppler sensors based on a peak frequency in the frequency spectrum generated for each of the plurality of Doppler sensors; The aggregate spectrum generating means generates the aggregate spectrum based on a plurality of selected frequency spectra.

3. 2. The biological information detection system according to claim 1, The aggregate spectrum generating means generates the aggregate spectrum, which is a frequency spectrum obtained by summing or averaging some or all of the frequency spectra generated for each of the multiple Doppler sensors.

4. 2. The biological information detection system according to claim 1, The biological information generating means generates biological information of the subject for the period based on a peak frequency in the aggregate spectrum.

5. acquiring Doppler data indicating a measurement result by each of a plurality of Doppler sensors provided facing the subject during a certain period of time; generating a frequency spectrum for each of the plurality of Doppler sensors based on the Doppler data indicative of a measurement result by the Doppler sensor; generating an aggregate spectrum based on some or all of the frequency spectra generated for each of the plurality of Doppler sensors; generating biological information of the subject for the period based on the aggregate spectrum; A biological information detection method comprising:

6. acquiring Doppler data indicating a measurement result by each of a plurality of Doppler sensors provided facing the subject during a certain period of time; generating a frequency spectrum for each of the plurality of Doppler sensors based on the Doppler data indicative of a measurement result by the Doppler sensor; generating an aggregate spectrum based on some or all of the frequency spectra generated for each of the plurality of Doppler sensors; generating biological information of the subject for the period based on the aggregate spectrum; A program for causing a computer to execute the following.

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