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

Abstract

A biological information detection system, a biological information detection method, and a program are provided that are capable of accurately measuring biological information such as the respiratory rate and heart rate of a subject. [Solution] A Doppler data acquisition unit 20 acquires Doppler data indicating the measurement results by each of multiple Doppler sensors provided facing the subject over a certain period of time. A frequency spectrum generation unit 22 generates a frequency spectrum for each of the multiple Doppler sensors based on the Doppler data indicating the measurement results by the Doppler sensor. An aggregate spectrum generation unit 26 generates an aggregate spectrum based on some or all of the frequency spectra generated for each of the multiple Doppler sensors. A bioinformation generation unit 28 generates bioinformation of the subject over the period of time based on the aggregate spectrum.

Description

[Technical field]

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

[0002] Various systems for measuring biological information such as the respiration rate and heart rate of a subject have been considered. As an example of such a system, Patent Document 1 describes a monitoring device that determines the respiration rate and heart rate in a non-contact manner using a microwave Doppler sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-134795 A Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors are considering measuring the biological information of a subject using a plurality of Doppler sensors in order to improve the accuracy of the measurement results of the biological information (here, for example, respiratory rate or heart rate).

[0005] When measuring biological information of a subject using multiple Doppler sensors, depending on the subject's position, posture, and other factors, some of the measurement results obtained from these multiple Doppler sensors may be low in accuracy.

[0006] Therefore, if biometric information is measured using each of these multiple Doppler sensors and a representative value such as the average value of the measured biometric information is used as the value of the subject's biometric information, the value of the biometric information obtained in this manner may not be a valid value.

[0007] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a bio-information detection system, a bio-information detection method, and a program capable of accurately measuring bio-information such as the respiratory rate and heart rate of a subject. [Means for solving the problem]

[0008] (1) The biometric information detection system of the present invention includes a Doppler data acquisition means for acquiring Doppler data indicating the measurement results by each of a plurality of Doppler sensors provided toward a subject over a certain period of time, a frequency spectrum generation means for generating a frequency spectrum based on the Doppler data indicating the measurement results by each of the plurality of Doppler sensors, an aggregate spectrum generation means for generating an aggregate spectrum based on some or all of the frequency spectra generated for each of the plurality of Doppler sensors, and a biometric information generation means for generating biometric information of the subject for the period based on the aggregate spectrum.

[0009] (2) In the bioinformation detection system described in (1), a selection means may be included 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, and the aggregate spectrum generation means may generate the aggregate spectrum based on the selected plurality of frequency spectra.

[0010] (3) In the bioinformation detection system described in (1) or (2), the aggregate spectrum generating means may generate 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.

[0011] (4) In the biometric information detection system according to any one of (1) to (3), the biometric information generating means may generate the biometric information of the subject for the period based on a peak frequency in the aggregate spectrum.

[0012] (5) The biometric information detection method of the present invention includes the steps of: acquiring Doppler data indicating the measurement results by each of a plurality of Doppler sensors provided toward a subject over a certain period of time, for each of the plurality of Doppler sensors; 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; generating an aggregate spectrum based on some or all of the frequency spectra generated for each of the plurality of Doppler sensors; and generating biometric information of the subject for the period based on the aggregate spectrum.

[0013] (6) A program according to the present invention is a program for causing a computer to execute the steps of: acquiring Doppler data indicating a measurement result by each of a plurality of Doppler sensors provided for a subject during a certain period of time for each of the plurality of Doppler sensors, generating a frequency spectrum for each of the plurality of Doppler sensors based on the Doppler data indicating the 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, and generating biological information of the subject during the period based on the aggregate spectrum. This program may be stored in a computer-readable information storage medium. Effect of the Invention

[0014] According to the present invention, it is possible to accurately measure biological information such as the respiratory rate and heart rate of a subject. [Brief description of the drawings]

[0015] [Figure 1] 1 is a configuration diagram of a biological information detection system according to an embodiment of the present invention. [Diagram 2] 1 is a functional block diagram of a signal processing device according to an embodiment of the present invention. [Diagram 3] 6A to 6C are diagrams illustrating an example of processing by a Doppler data acquisition unit. [Figure 4] 5 is a flowchart showing an example of the flow of a frequency spectrum selection process performed in the signal processing device according to the embodiment of the present invention. FIG. [Diagram 5] FIG. 2 is a diagram illustrating an example of generating an aggregate spectrum. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment 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.

[0018] 1, the Doppler sensor unit 12 is attached to the headboard of the bed 14. Here, the multiple Doppler sensors 16 may be provided symmetrically with respect to the center line of the bed 14 (a line that passes through the center of the bed 14 in the width direction and extends in the length direction of the bed 14). The multiple Doppler sensors 16 may also be provided lined up perpendicular to the length direction of the bed 14 (a direction along the center line of the bed 14). The multiple Doppler sensors 16 may also be provided lined up in a row at equal intervals.

[0019] The Doppler sensors 16 are all provided so as to face the lengthwise direction (longitudinal direction) of the bed 14, and emit microwaves in the lengthwise direction of the bed 14. The microwaves are reflected by the chest of the person being measured sleeping on the bed 14, and the reflected waves are received by each Doppler sensor 16. Each Doppler sensor 16 generates a Doppler signal from the reflected waves that indicates chest movement associated with breathing, and outputs Doppler data by digitizing this Doppler signal. The microwaves emitted from each Doppler sensor 16 have a slight difference in frequency, which prevents mutual interference.

[0020] The reflected wave is frequency shifted due to the Doppler effect, and by observing this, the breathing rate of the subject can be obtained. The reflected wave is detected by quadrature detection as a Doppler signal including an I signal, which is an in-phase component with the transmitted wave, and a Q signal, which is an orthogonal component, and output in digital form to the signal processing device 10. The Doppler signal input to the signal processing device 10 is time-series data, and indicates the amplitude (I component and Q component) at each time.

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

[0022] 2 is a functional block diagram of a 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 aggregate 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 to 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 acquiring section 20 acquires, for each of a plurality of Doppler sensors 16 provided facing the subject, Doppler data indicating the measurement results by the Doppler sensor 16 during a certain period of time.

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

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

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

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

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

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

[0030] The frequency spectrum selection unit 24 selects a plurality of frequency spectra from among the frequency spectra generated for each of the plurality of Doppler sensors 16, based on, for example, a peak frequency in the frequency spectrum 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 flow diagram illustrated in Fig. 4. Here, for example, a process of selecting a plurality of frequency spectra from among those generated for the I signal data and Q signal data of each of six pieces of Doppler data D(1,1), D(1,2), D(1,3), D(1,4), D(1,5), and D(1,6) extracted for the first time window will be described.

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

[0033] Then, the frequency spectrum selection unit 24 calculates a representative value (here, for example, an average value) of the respiration rates identified 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 respiratory rate (i.e., an outlier respiratory rate) whose difference from the representative value calculated in the process shown in S102 is a predetermined value (e.g., 5) or more (S103).

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

[0036] If there is no outlier respiration rate (S103: N), the process shown in this processing example is terminated. Note that, in the process shown in this processing example, none of the frequency spectra may be excluded, and all frequency spectra may be selected.

[0037] The frequency spectrum that is not excluded in the above-mentioned process corresponds to the frequency spectrum selected from the frequency spectrum generated for the I signal data and the Q signal data of each of the six Doppler data extracted for the first time window. The above-mentioned process is performed for each of the multiple time windows.

[0038] The aggregate spectrum generating unit 26 generates an aggregate spectrum based on, for example, a part or all of the frequency spectra generated for each of the multiple Doppler sensors 16. As shown in FIG. 5, for the first time window, the aggregate spectrum (1) may be generated by adding the amplitudes (intensities) of the frequency spectrum of the I signal data of D(1,1), the frequency spectrum of the Q signal data of D(1,1), the frequency spectrum of the I signal data of D(1,2), the frequency spectrum of the Q signal data of D(1,2), the frequency spectrum of the I signal data of D(1,3), the frequency spectrum of the Q signal data of D(1,3), ..., the frequency spectrum of the Q signal data of D(1,6) for each frequency. The aggregate spectrum (1) corresponds to the aggregate spectrum of the first time window. In this way, the aggregate spectrum generating unit 26 may generate an aggregate spectrum that is a frequency spectrum obtained by summing up a part or all of the frequency spectra generated for each of the multiple Doppler sensors 16.

[0039] Furthermore, the aggregate spectrum generating unit 26 may generate an aggregate spectrum, which is a frequency spectrum obtained by averaging some or all of the frequency spectra generated for each of the multiple Doppler sensors 16 .

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

[0041] In Figure 5, aggregate spectrum (1), which is the aggregate spectrum of the first time window, is shown. In a similar manner, aggregate spectrum (2), which is the aggregate spectrum of the second time window, aggregate spectrum (3), which is the aggregate spectrum of the third time window, etc. are generated.

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

[0043] Furthermore, the biological information generating unit 28 may identify the maximum amplitude and the second largest amplitude in the aggregate spectrum. Then, the biological information generating unit 28 may generate an amplitude ratio by dividing the maximum amplitude by the second largest amplitude.

[0044] Furthermore, the bioinformation generating unit 28 may generate an amplitude ratio for each of the aggregate spectra calculated for a plurality of time windows (e.g., the first time window to the 30th time window). Then, the bioinformation generating unit 28 may extract aggregate spectra having an amplitude ratio equal to or greater than a predetermined threshold (e.g., 1.5). Then, the bioinformation generating unit 28 may generate an average value of the respiration rates generated for each of the aggregate spectra having an amplitude ratio equal to or greater than a predetermined threshold (e.g., 1.5) as the respiration rate for a period (e.g., one minute) associated with the plurality of time windows.

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

[0046] In this embodiment, the frequency spectrum may not be selected by the frequency spectrum selector 24. The aggregate spectrum generator 26 may generate an aggregate spectrum for a certain period of time by using all frequency spectra for that period of time generated by the frequency spectrum generator 22.

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

[0048] In addition, it is not necessary to convert each of the I signal data and the Q signal data into a frequency spectrum. For example, data of a complex signal having an I component as a real part and a Q component as an imaginary part may be converted into a frequency spectrum. Then, an aggregate spectrum may be generated based on the frequency spectrum.

[0049] When measuring the biometric information of a subject using multiple Doppler sensors 16, depending on the subject's position, posture, etc., some of the measurement results obtained from each of the multiple Doppler sensors 16 may be low in accuracy.

[0050] Therefore, if biometric information is measured using each of the multiple Doppler sensors 16 and a representative value such as the average value of the measured biometric information is used as the value of the subject's biometric information, the value of the biometric information obtained in this manner may not be a valid value.

[0051] As described above, in this embodiment, the biological information is generated based on the aggregate spectrum. Therefore, according to this embodiment, it is possible to measure the biological information of the subject more accurately than when a representative value such as an average value of the measured biological information is used as the value of the biological information of the subject.

[0052] Also, for example, the angles of the Doppler sensors 16 with respect to the subject are different, and therefore the peak frequencies of the frequency spectrum based on the measurement results may be slightly different. Here, when multiple Doppler sensors 16 are arranged in a line perpendicular to the length direction of the bed 14, multiple Doppler sensors 16 are arranged symmetrically with respect to the center line of the bed 14, multiple Doppler sensors 16 are arranged in a line at equal intervals, or other arrangements are adopted, an aggregate spectrum is generated in which the frequency spectra corresponding to the individual Doppler sensors 16 are appropriately averaged, and as a result, it becomes possible to measure the biological information of the subject with higher accuracy.

[0053] The present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above description, the respiration rate is generated as the biological information of the subject, but the heart rate can also be generated in the same manner. [Explanation of symbols]

[0054] 1 Biometric information detection system, 10 signal processing device, 12 Doppler sensor unit, 14 bed, 16, 16a, 16b, 16c, 16d, 16e, 16f Doppler sensors, 20 Doppler data acquisition unit, 22 frequency spectrum generation unit, 24 frequency spectrum selection unit, 26 aggregate 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; a selection means for selecting, from the frequency spectra generated for each of the plurality of Doppler sensors, the frequency spectrum generated for each of a plurality of Doppler sensors that is a part of the plurality of Doppler sensors, based on a peak frequency in the frequency spectrum generated for each of the plurality of Doppler sensors; an aggregate spectrum generating means for generating an aggregate spectrum based on the selected plurality of frequency spectra; 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, The aggregate spectrum generating means generates the aggregate spectrum, which is a frequency spectrum obtained by summing or averaging the selected plurality of frequency spectra.

3. 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.

4. 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; selecting, from the frequency spectra generated for each of the plurality of Doppler sensors, the frequency spectra generated for each of a plurality of Doppler sensors that are a part of the plurality of Doppler sensors, based on a peak frequency in the frequency spectrum generated for each of the plurality of Doppler sensors; generating an aggregate spectrum based on a selected number of said frequency spectra; generating biological information of the subject for the period based on the aggregate spectrum; A biological information detection method comprising:

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; selecting, from the frequency spectra generated for each of the plurality of Doppler sensors, the frequency spectra generated for each of a plurality of Doppler sensors that are a part of the plurality of Doppler sensors, based on a peak frequency in the frequency spectrum generated for each of the plurality of Doppler sensors; generating an aggregate spectrum based on a selected number of said frequency spectra; 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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