Living body condition measuring device, living body condition measuring method, program, and living body condition measuring system

Abstract

To reduce an arithmetic amount for measuring a living body condition using a reflection signal.SOLUTION: A living body condition measuring device 1 includes: a signal acquisition unit 153 for acquiring a reflection signal generated when a chirp signal of a frequency band of a millimeter-wave band or higher transmitted at each predetermined frame time is reflected by a person U to be measured; a signal conversion unit 154 for converting the reflection signal to a complex signal of a frequency region at each frame time; a frequency selection unit 155 for selecting a frequency corresponding to a frequency component with relatively large intensity of a plurality of frequency components included in the complex signal; and a measuring unit 156 for specifying a living body condition of the person U to be measured on the basis of a change in the phase of the frequency component corresponding to the frequency selected by the frequency selection unit 155 over a frequency fixing period longer than the frame time.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a biological condition measuring device, a biological condition measuring method, a program, and a biological condition measuring system for measuring a biological condition of a person. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known a method of measuring a heart rate by transmitting a millimeter wave signal and analyzing a reflected wave signal generated when the transmitted millimeter wave signal is reflected by a human body (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-214876 A Summary of the Invention [Problem to be solved by the invention]

[0004] The transmitted millimeter wave signal is reflected by various objects in the space, generating different reflected signals. When analyzing these many reflected signals, the amount of calculation required to measure biological conditions such as heart rate and breathing becomes enormous.

[0005] The present invention has been made in consideration of these points, and has an object to reduce the amount of calculation required to measure a living body condition using a reflected signal. [Means for solving the problem]

[0006] A biological condition measuring device of a first aspect of the present invention has a signal acquiring unit that acquires a reflected signal generated when a chirp signal in a frequency band equal to or higher than the millimeter wave band transmitted every predetermined frame time is reflected from a subject, a signal converting unit that converts the reflected signal into a complex signal in the frequency domain every frame time, a frequency selecting unit that selects a frequency corresponding to a frequency component having a relatively large intensity from among a plurality of frequency components contained in the complex signal, and a measuring unit that identifies the biological condition of the subject based on a change in phase of the frequency component corresponding to the frequency selected by the frequency selecting unit over a frequency fixed period longer than the frame time.

[0007] The measurement unit may generate a phase signal by arranging the phases of the frequency components in a time series over the frequency fixed period, and identify the biological condition based on the frequency components in the phase signal that are included in a period range or frequency range corresponding to the biological condition.

[0008] When a time interval between peaks in the phase signal is included in a range assumed as a period of the biological state to be identified, the measurement unit may identify the time interval as the period of the biological state to be identified.

[0009] The measurement unit may transform the phase signal into a frequency domain, and identify a frequency component having a first intensity or higher among a plurality of frequency components included in a respiratory frequency band as the respiratory frequency, and identify a frequency component having a second intensity or higher among a plurality of frequency components included in a heartbeat frequency band as the heartbeat frequency.

[0010] The measurement unit may determine a heart rate based on the phase signal over the frequency locking period, and determine a respiratory rate based on the phase signal over a period that is 1.5 to 2.5 times the frequency locking period. The frequency locking period is, for example, 5 to 10 seconds.

[0011] The measurement section may correct the phase signal so as to reduce discontinuity in the phase signal at a timing when the frequency selected by the frequency selection section is switched.

[0012] The frequency selection unit may select a frequency corresponding to a frequency component having a relatively large intensity for each frequency fixing period. For example, the frequency selection unit selects a frequency corresponding to a frequency component having a largest intensity among the plurality of frequency components.

[0013] The signal acquiring unit may acquire the reflected signals generated by reflection from the multiple subjects, and the frequency selecting unit may select frequencies from the multiple frequency components corresponding to a number of frequency components corresponding to the number of subjects.

[0014] The biological condition measuring device may further have a memory unit that stores a frequency corresponding to the frequency component selected by the frequency selection unit, and the measurement unit may identify the biological condition of the subject based on a change in phase of the frequency component corresponding to the frequency stored in the memory unit.

[0015] A biological condition measuring method of a second aspect of the present invention includes the steps of: acquiring a reflected signal generated when a chirp signal in a frequency band equal to or higher than the millimeter wave band transmitted every predetermined frame time is reflected from a subject; a signal conversion unit converting the reflected signal into a complex signal in the frequency domain every frame time; selecting a frequency corresponding to a frequency component having a relatively large intensity from among a plurality of frequency components contained in the complex signal; and identifying the biological condition of the subject based on a change in phase of the frequency component corresponding to the selected frequency over a fixed frequency period longer than the frame time.

[0016] A program of a third aspect of the present invention causes a computer to execute the steps of acquiring a reflected signal generated when a chirp signal in a frequency band equal to or higher than the millimeter wave band transmitted at each predetermined frame time is reflected off the subject, a signal conversion unit converting the reflected signal into a complex signal in the frequency domain at each frame time, selecting a frequency corresponding to a frequency component having a relatively large intensity from among a plurality of frequency components contained in the complex signal, and identifying the biological condition of the subject based on a change in phase of the frequency component corresponding to the selected frequency over a frequency fixed period longer than the frame time.

[0017] A fourth aspect of the present invention provides a biological condition measuring system comprising a biological condition measuring device and an external device capable of communicating with the biological condition measuring device, wherein the biological condition measuring device has a signal acquiring unit that acquires a reflected signal generated when a chirp signal in a frequency band equal to or higher than the millimeter wave band and transmitted every predetermined frame time is reflected off the subject, and the biological condition measuring device or the external device has a signal converting unit that converts the reflected signal into a complex signal in the frequency domain every frame time, a frequency selecting unit that selects a frequency corresponding to a frequency component having a relatively large intensity from among a plurality of frequency components contained in the complex signal, and a measuring unit that identifies the biological condition of the subject based on a change in phase of the frequency component corresponding to the frequency selected by the frequency selecting unit over a frequency fixed period longer than the frame time. Effect of the Invention

[0018] According to the present invention, it is possible to reduce the amount of calculation required to measure a biological condition using a reflected signal. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram showing an overview of a biological state measuring system S1. [Diagram 2] FIG. 13 is a diagram showing an example of a screen showing measurement results displayed on the information terminal 2. [Diagram 3]13 is a diagram showing another example of a screen showing measurement results displayed on the information terminal 2. FIG. [Figure 4] FIG. 1 is a diagram showing a configuration of a biological state measuring device 1. [Diagram 5] 2 is a diagram for explaining a transmission range of a transmitter 11 and a reception range of a receiver 12. FIG. [Figure 6] FIG. 13 is a diagram illustrating an example of a frequency fixing period. [Figure 7] 13 is a diagram for explaining the operation of a measurement unit 156. FIG. [Figure 8] 13 is a diagram for explaining the operation of a measurement unit 156. FIG. [Figure 9] 13 is a diagram for explaining a process in which the measurement section 156 tracks the biological condition of the subject U. FIG. [Figure 10] 3 is a flowchart showing an outline of a process flow in the biological state measuring device 1. [Figure 11] 10 is a flowchart showing details of a process for analyzing a reflected signal in the biological state measuring device 1. [Figure 12] FIG. 13 is a diagram showing the configuration of a biological state measuring system S2 according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] [Outline of the biological condition measurement system S1] 1 is a diagram showing an overview of a biological condition measuring system S1. The biological condition measuring system S1 is a system for measuring a human biological condition. The biological condition is a heart rate or a respiratory rate, or a movement of a part of a human body. The biological condition is represented by, for example, the heart rate, the respiratory rate, or the number of changes in movement per unit time.

[0021] The biological state measuring system S1 includes a biological state measuring device 1 and an information terminal 2. The biological state measuring device 1 can measure the biological state of a person (subject U in FIG. 1) within the reach of radio waves emitted by the biological state measuring device 1. The information terminal 2 is a terminal for displaying the results of measurements by the biological state measuring device 1 and for controlling the biological state measuring device 1, and is, for example, a computer, a tablet, or a smartphone.

[0022] The biological state measuring device 1 transmits radio waves of a frequency equal to or higher than the millimeter wave band as a transmission signal in multiple directions, and receives a reflected signal generated when the transmitted radio waves are reflected by a surrounding object. The biological state measuring device 1 determines the distance to the object that reflected the transmission signal based on the propagation time from when the transmission signal is transmitted until when the reflected signal is received. There are tissues in the human body that easily reflect radio waves and tissues that do not easily reflect radio waves, and the biological state measuring device 1 can determine the movement of the tissue by determining the distance to the tissue that easily reflects radio waves. For example, the biological state measuring device 1 measures the heart rate by determining the movement of the heart, and measures the respiratory rate by determining the movement of the pleura.

[0023] The transmission signal is, for example, a signal in the 60 GHz band. Since the wavelength of a 60 GHz signal is 5 mm, a 5 mm change in the position of the object from which the transmission signal is reflected corresponds to a phase change of 2π. The biological state measuring device 1 can detect minute changes of 5 mm or less in parts of the heart, lungs, etc. by identifying the change in the phase of the reflected signal.

[0024] The biological state measuring device 1 transmits a chirp signal whose frequency changes over time as a transmission signal. When the biological state measuring device 1 transmits a chirp signal, the biological state measuring device 1 converts the reflected signal into the frequency domain by Fourier transforming it, and identifies the frequency contained in the reflected signal, thereby making it possible to measure with high accuracy the propagation time from when the signal of that frequency is transmitted to when it is received.

[0025] By the way, a chirp signal is a signal whose frequency changes over time. Therefore, the reflected signal after the chirp signal is reflected by an object contains signals of many frequencies included in the frequency band contained in the chirp signal. If this reflected signal is converted into the frequency domain and then analyzed, the amount of calculation required for analysis will be enormous if all signals in a wide frequency band are analyzed.

[0026] The inventors of the present application have found that the intensity (i.e., amplitude or power) of each frequency component contained in the reflected signal varies depending on the frequency, and the frequency at which the intensity is high varies depending on the position of the subject U. Based on this principle, the biological state measuring device 1 selects a frequency corresponding to a frequency component with a relatively high intensity from among a plurality of frequency components contained in the reflected signal, and identifies the biological state of the subject U based on a change in phase of the frequency component corresponding to the selected frequency over a predetermined frequency fixing period. The frequency fixing period will be described in detail later, but the frequency fixing period is a time that is preset as a time longer than the frame time of FFT (Fast Fourier Transform) processing executed by the biological state measuring device 1, and is, for example, 5 seconds or more and less than 10 seconds.

[0027] Such a configuration of the biological state measuring device 1 can significantly reduce the amount of calculation and improve the accuracy of the analysis. In addition, since the frequency to be analyzed is periodically reselected, the accuracy of the analysis can be maintained at a high level even if the position of the subject U changes.

[0028] [Measurement results display screen] Fig. 2 is a diagram showing an example of a screen showing the measurement results displayed on the information terminal 2. The screen shown in Fig. 2 includes a measurement result display area R1 and an operation area R2.

[0029] At the top of area R1, the distance from the biological state measuring device 1 to the nearest subject U1, and the respiration rate and heart rate of the subject U1 are shown. Also shown are the respiration waveform and heart rate waveform of the subject U1. Below the respiration waveform and heart rate waveform, the distance to each of the other subjects U, and the respiration rate and heart rate of the subject U are shown in association with each of the other subjects U. Area R1 also shows a diagram showing the relationship between the distance to the subject U and the strength of the received reflected signal.

[0030] Area R2 displays images of operation buttons for accepting operations to start, interrupt, and end the measurement. The "Update" button in area R2 is a button for updating the measurement results displayed in area R1 to the latest measurement results.

[0031] Fig. 3 is a diagram showing another example of a screen showing measurement results displayed on the information terminal 2. Fig. 3 is a diagram showing the positions of multiple subjects U whose biological conditions have been measured. The black squares in Fig. 3 indicate the positions of the biological condition measuring device 1, and other white figures indicate the positions of multiple subjects U who have reflected the transmitted signal. The biological condition measuring device 1 may include the image shown in Fig. 3 on the screen shown in Fig. 2, or may cause the information terminal 2 to display the image shown in Fig. 3 when a predetermined operation is performed on the screen shown in Fig. 2.

[0032] [Configuration of biological state measuring device 1] 4 is a diagram showing the configuration of the biological condition measuring device 1. The biological condition measuring device 1 has a transmitting unit 11, a receiving unit 12, an external connection unit 13, a storage unit 14, and a control unit 15. The control unit 15 has an operation accepting unit 151, a radio wave control unit 152, a signal acquiring unit 153, a signal converting unit 154, a frequency selecting unit 155, and a measuring unit 156.

[0033] The transmitter 11 transmits a transmission signal in a frequency band equal to or greater than the millimeter wave band at a predetermined time interval under the control of the radio wave control unit 152. The transmitter 11 transmits a chirp signal at a period of, for example, 12.5 milliseconds. The transmitter 11 has a signal generating circuit that generates a chirp signal, and an antenna for transmitting the transmission signal as a radio wave. As an example, the biological state measuring device 1 may have a plurality of transmitters 11 that transmit transmission signals to different ranges at different times.

[0034] The transmitting unit 11 transmits a transmission signal at a time interval less than half the minimum value of the period in which a preset biological condition changes. For example, if the maximum heart rate is assumed to be 150 beats / minute, the minimum value of the period in which the heart rate fluctuates is 0.4 seconds. Therefore, the transmitting unit 11 transmits a transmission signal at a time interval less than 0.2 seconds. As an example, the transmitting unit 11 according to this embodiment transmits a transmission signal at a period of 12.5 milliseconds (equivalent to 80 Hz). By transmitting a transmission signal at such a time interval, the biological condition measuring device 1 can identify the change state of a part of the body of the subject U based on the reflected signal received by the receiving unit 12 at that time interval.

[0035] The length of the transmission signal transmitted by the transmitting unit 11 is arbitrary, but it is desirable that the length be sufficiently shorter than the time interval for transmitting the transmission signal, for example, within 2 milliseconds. When the biological state measuring device 1 has multiple transmitting units 11, the length of the transmission signal transmitted by the transmitting units 11 is determined based on the number of transmitting units 11. Specifically, the length of the transmission signal is less than the time interval for transmitting the transmission signal divided by the number of transmitting units 11. Setting the length of the transmission signal in this manner allows the multiple transmitting units 11 to transmit the transmission signal at different timings.

[0036] The receiving unit 12 receives a plurality of reflected signals generated when the transmission signal is reflected by a plurality of subjects U. As an example, the receiving unit 12 has a plurality of receiving units 12 each receiving a reflected signal arriving from a different range. The receiving unit 12 inputs the received reflected signal to the measuring unit 156.

[0037] Fig. 5 is a diagram for explaining the transmission range of the transmitter 11 and the reception range of the receiver 12. Fig. 5(a) shows a schematic diagram of the ranges in which the transmitters 11 transmit transmission signals and the positions of multiple subjects U when the biological state measuring device 1 has transmitters 11A, 11B, and 11C. Fig. 5(b) shows a schematic diagram of the ranges in which the receivers 12 receive reflected signals and the positions of multiple subjects U when the biological state measuring device 1 has receivers 12A, 12B, and 12C.

[0038] In the example shown in Fig. 5, the transmission range of each transmitter 11 is a sector shape of ±60 degrees (120 degrees), and the reception range of each receiver 12 is a sector shape of ±60 degrees (120 degrees). Although not shown in Fig. 5, the transmitter 11 transmits a transmission signal to a predetermined range in the vertical direction, and the receiver 12 receives a reflected signal arriving from the predetermined range in the vertical direction. The predetermined range is, for example, a range of ±15 degrees (30 degrees) in the horizontal direction.

[0039] 5, it is desirable that the transmission range of the transmitter 11 and the reception range of the receiver 12 do not completely match. The biological state measuring device 1 can determine that the subject U is present in a range where the transmission range of the transmitter 11 that transmitted the transmission signal overlaps with the reception range of the receiver 12 that received the reflected signal based on the transmission signal. Therefore, when the transmission range and the reception range do not completely match, the number of overlapping ranges between the transmission range and the reception range increases, and the resolution with which the biological state measuring device 1 determines the position of the subject U increases.

[0040] The external connection unit 13 has a communication interface for transmitting and receiving data to and from the information terminal 2. The external connection unit 13 has, for example, a USB interface. The external connection unit 13 receives operation data input at the information terminal 2, and inputs the received data to the operation reception unit 151. In addition, the external connection unit 13 transmits data indicating the measurement result output by the output unit 155 to the information terminal 2.

[0041] The storage unit 14 has a storage medium such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage unit 14 stores a program executed by the control unit 15. The storage unit 14 also stores the reflected signal received by the receiving unit 12 and the measurement result generated by the control unit 15 by analyzing the reflected signal.

[0042] Furthermore, the storage unit 14 stores the frequency selected by the frequency selection unit 155 as a frequency corresponding to a frequency component used when the measurement unit 156 analyzes the reflected signal. This frequency stored in the storage unit 14 is updated at predetermined intervals (for example, a frequency fixing period).

[0043] The control unit 15 has, for example, a CPU (Central Processing Unit). The control unit 15 executes a program stored in the storage unit 14 to function as an operation reception unit 151, a radio wave control unit 152, a signal acquisition unit 153, a signal conversion unit 154, a frequency selection unit 155, and a measurement unit 156.

[0044] The operation receiving unit 151 receives operation data input from the information terminal 2 via the external connection unit 13, thereby receiving an operation by a user. The operation receiving unit 151 receives, for example, an operation to start measurement, an operation to interrupt measurement, an operation to end measurement, or an operation to update the measurement result, which is input in the area R2 shown in FIG.

[0045] Furthermore, the operation accepting unit 151 may accept an operation to set a range within which the measuring unit 156 identifies a biological condition (hereinafter may be referred to as a "specification target range"). For example, the operation accepting unit 151 accepts the setting of a range of distance to the subject U within which the biological condition is to be identified. The operation accepting unit 151 may accept the setting of a range within which the biological condition is to be identified within a range from 0 degrees to 360 degrees based on a predetermined side (for example, the front direction) of the biological condition measuring device 1.

[0046] As an example, the operation accepting unit 151 accepts the setting of a numerical value indicating an angle such as "0 degrees to 90 degrees" or "270 degrees to 90 degrees." The operation accepting unit 151 may accept the setting of a range for identifying a biometric condition by displaying a circular image as shown in Fig. 3 on the information terminal 2 via the external connection unit 13 and accepting an operation of surrounding the range for identifying a biometric condition.

[0047] The radio wave control unit 152 controls the transmitting unit 11 and the receiving unit 12. The radio wave control unit 152 controls, for example, the timing at which the transmitting unit 11 transmits a transmission signal. The radio wave control unit 152 also controls the range in which the transmitting unit 11 transmits a transmission signal and the range in which the receiving unit 12 receives a reflected signal.

[0048] As an example, the radio wave control unit 152 controls the multiple transmission units 11 so that one or more of the multiple transmission units 11 corresponding to the specific target range accepted by the operation acceptance unit 151 transmits a transmission signal. Also, the radio wave control unit 152 controls the multiple reception units 12 so that one or more of the reception units 12 corresponding to the specific target range accepted by the operation acceptance unit 151 receives a reflected signal. In this way, the radio wave control unit 152 causes the transmission unit 11 corresponding to the specific target range to transmit a transmission signal and causes the reception unit 12 corresponding to the specific target range to receive the reflected signal, thereby reducing the influence of unnecessary reflected signals coming from a range where the subject U is not present, thereby improving the measurement accuracy.

[0049] After the measuring unit 156 identifies the position of the subject U, the radio wave control unit 152 may cause the transmitting units 11 corresponding to the range corresponding to the position of the subject U to transmit a transmission signal, and may cause the transmitting units 11 corresponding to all ranges to periodically transmit a transmission signal. By operating the radio wave control unit 152 in this manner, the number of reflected signals generated when the transmitted signal is reflected by objects other than the subject U is reduced, thereby reducing the load on the control unit 15 when analyzing the reflected signals.

[0050] The measuring unit 156 measures multiple propagation times from when the transmitting unit 11 transmits a transmission signal to when the receiving unit 12 receives multiple reflected signals, in order to identify the distance from the biological state measuring device 1 to the subject U and the direction of the subject U relative to the biological state measuring device 1, by digital signal processing of the reflected signal received by the receiving unit 12. When the biological state measuring device 1 has multiple receiving units 12, the measuring unit 156 measures, for each receiving unit 12, the propagation time from when the transmitting unit 11 transmits a transmission signal to when the multiple receiving units 12 receive a reflected signal.

[0051] The measurement unit 156 may measure the amount of change in the frequency of a chirp signal included in the transmission signal or the amount of change in the phase of the transmission signal as the amount of change in the propagation time. Since the amount of change in the frequency of a chirp signal or the amount of change in the phase of the transmission signal is equivalent to the amount of change in the propagation time, even when the measurement unit 156 measures the amount of change in the frequency of a chirp signal or the amount of change in the phase of the transmission signal, it can be considered that the amount of change in the propagation time has been measured.

[0052] When the biological state measuring device 1 has a plurality of transmitting units 11, the measuring unit 156 measures the propagation time from when each of the plurality of transmitting units 11 transmits a transmission signal until when the receiving unit 12 receives a reflected signal for each transmitting unit 11. The measuring unit 156 stores propagation time data indicating the measured propagation time in the storage unit 14 in association with each transmitting unit 11. When the biological state measuring device 1 has a plurality of receiving units 12, the measuring unit 156 measures the propagation time from when the transmitting unit 11 transmits a transmission signal until when the plurality of receiving units 12 receive a reflected signal for each receiving unit 12. The measuring unit 156 stores propagation time data indicating the measured propagation time in association with each receiving unit 12 in the storage unit 14.

[0053] When the biological state measuring device 1 has multiple transmitting units 11 and multiple receiving units 12, the measurement unit 156 measures the propagation time from when each of the multiple transmitting units 11 transmits a transmission signal to when the multiple receiving units 12 receive a reflected signal for each combination of the transmitting units 11 and the receiving units 12. The measurement unit 156 stores propagation time data indicating the measured propagation time in the storage unit 14 in association with the combination of the transmitting unit 11 and the receiving unit 12.

[0054] The signal acquiring unit 153 acquires a reflected signal generated when a transmission signal (i.e., a chirp signal) in a frequency band equal to or higher than the millimeter wave band, transmitted at each predetermined frame time, is reflected by the subject U. The frame time is a time corresponding to a period during which the signal converting unit 154 executes an FFT to convert the reflected signal into a signal in the frequency domain. The signal converting unit 154 may acquire a plurality of reflected signals generated by reflection from a plurality of subjects. The signal converting unit 154 inputs the acquired reflected signal to the signal converting unit 154.

[0055] The signal converter 154 converts the reflected signal into a complex signal in the frequency domain for each frame time. As an example, the transmission signal is quadrature modulated data, and the signal converter 154 samples the I data and Q data in the received quadrature modulated data at each predetermined sampling time and performs FFT on the sampled value to convert the reflected signal into a complex signal. The vector of the complex signal corresponds to the intensity and phase of the reflected signal.

[0056] The signal conversion unit 154 generates 512 bytes of digital data corresponding to I data and 512 bytes of digital data corresponding to Q data by sampling 256 times per frame time. When the frame time is 12.5 milliseconds, the signal conversion unit 154 converts 80 frames per second into a complex signal and generates 512×2×80 bytes=80 KB of data.

[0057] The frequency selection unit 155 selects a frequency corresponding to a frequency component having a relatively large intensity (i.e., amplitude or power) from among a plurality of frequency components included in the complex signal. The frequency selection unit 155 selects, for example, a frequency corresponding to a frequency component having the largest intensity from among a plurality of frequency components. Specifically, the frequency selection unit 155 selects a frequency corresponding to a complex signal having the largest intensity from a plurality of complex signals corresponding to a plurality of frequencies generated by the signal conversion unit 154 in a certain frame, and stores the selected frequency in the storage unit 14.

[0058] The frequencies thus stored in the storage unit 14 are held over a frequency fixing period in the storage unit 14. That is, the frequency selection unit 155 selects a frequency corresponding to a frequency component with a relatively large intensity for each frequency fixing period.

[0059] FIG. 6 is a diagram showing an example of a frequency fixing period. The horizontal axis of FIG. 6 indicates time, and the vertical axis indicates the amount of change in the biological state. The frequency fixing period is preferably longer than the period in which the biological state to be measured varies in order to ensure the continuity of the signal, and is, for example, 5 seconds or more. In addition, when the position of the subject U changes, it is preferable to use a frequency suitable for the position after the change, so the frequency fixing period is, for example, less than 10 seconds. That is, the frequency fixing period is preferably 5 seconds or more and less than 10 seconds, and as an example, it is 6.4 seconds, which corresponds to 512 frames, as shown in FIG. 6.

[0060] The frequency selection unit 155 may select a plurality of frequencies corresponding to a predetermined number of frequency components in ascending order of intensity from among the plurality of frequency components. The predetermined number is set via the operation reception unit 151 and stored in the storage unit 14, and is, for example, 4. Even if noise is superimposed on some of the selected frequencies by the frequency selection unit 155, reducing reliability, the measurement unit 156 can use other frequencies to maintain the accuracy of identifying the biological state.

[0061] The frequency selection unit 155 may select, from among the multiple frequency components, frequencies corresponding to the number of frequency components corresponding to the number of subjects U. For example, the frequency selection unit 155 selects a number of frequencies obtained by multiplying the number of frequencies selected for one subject U by the number of subjects set via the operation reception unit 151. Although details will be described later, by operating the frequency selection unit 155 in this manner, when multiple subjects U are present in different positions, the measurement unit 156 can analyze the frequency components suitable for each subject U, thereby identifying the biological condition of each subject U with high accuracy.

[0062] The measuring unit 156 analyzes the reflected signal to identify three elements: the distance between the biological state measuring device 1 and the person U, the direction of the person U relative to the biological state measuring device 1, and the moving speed of the person U, thereby identifying the biological state of the person U. The measuring unit 156 identifies the biological state of the person U based on a change in phase of the frequency component corresponding to the frequency selected by the frequency selecting unit 155 over a frequency fixed period longer than the frame time. The operation of the measuring unit 156 will be described in detail below.

[0063] The measuring unit 156 determines the distance between the biological state measuring device 1 and the subject U based on the propagation time from when the transmitting unit 11 transmits a transmission signal to when the receiving unit 12 receives a reflected signal. The measuring unit 156 determines the direction of the subject U by a combination of the transmitting unit 11 that transmits the transmission signal and the receiving unit 12 that receives the reflected signal. The measuring unit 156 determines the period of movement of parts of the subject U based on the period of change in the propagation time.

[0064] Furthermore, the measuring unit 156 determines the moving speed of the subject U based on the amount of change in the propagation time and the amount of change in the direction of the subject U. The measuring unit 156 can also determine the moving speed of the subject U by calculating an angular frequency based on the magnitude of the change in phase of a reflected signal based on a chirp signal transmitted at a constant time interval.

[0065] Although the method by which the measurement unit 156 specifies the propagation time based on the reflected signal is arbitrary, the measurement unit 156 specifies, in the frequency domain, the frequency component selected by the frequency selection unit 155 among the multiple frequency components included in the chirp signal constituting the reflected signal, and specifies as the propagation time the difference between the time when the transmission unit 11 transmits the frequency component and the time when the reception unit 12 receives the frequency component included in the reflected signal. In order to improve the measurement accuracy, the measurement unit 156 may measure the propagation time by specifying the propagation time for multiple frequency components corresponding to the multiple frequencies selected by the frequency selection unit 155, and calculating a statistical value (e.g., an average value or a median value) of the specified propagation times.

[0066] Fig. 7 is a diagram for explaining the operation of the measurement unit 156. The white rectangles in Fig. 7 indicate transmission signals transmitted by the transmitter 11, and the black rectangles indicate reflected signals received by the receiver 12. In the example shown in Fig. 7, the transmitters 11A, 11B, and 11C sequentially transmit transmission signals at times T1, T2, and T3, and then the transmitters 11A, 11B, and 11C sequentially transmit transmission signals at times T4, T5, and T6.

[0067] 7, the cycle in which the transmitting unit 11 transmits a transmission signal is set to a time longer than (time length of the transmission signal+time during which a reflected signal may be received)×(number of transmitting units 11). By setting the cycle in which the transmission signal is transmitted in this manner, it is possible to prevent reflected signals in response to transmission signals transmitted by a plurality of transmitting units 11 from reaching the biological state measuring device 1 at the same time.

[0068] The measuring unit 156 measures the time from when each of the transmitting units 11A, 11B, and 11C transmits a transmission signal to when it receives a reflected signal. In the example shown in Fig. 7, the measuring unit 156 measures that the receiving unit 12A receives a reflected signal after a time period D1 has elapsed since the transmitting unit 11A transmitted a transmission signal at time T1. The reflected signal is a reflected signal generated when the transmission signal transmitted by the transmitting unit 11A is reflected by the subject U1 in the example shown in Fig. 5.

[0069] The measurement unit 156 also measures that the receiving unit 12A has received a reflected signal even after a time D2 has elapsed since the transmitting unit 11A transmitted a transmission signal. In the example shown in FIG. 5, the reflected signal is a reflected signal generated when the transmission signal transmitted by the transmitting unit 11A is reflected by the subject U2, who is a subject U different from the subject U1. Furthermore, the measurement unit 156 measures that the receiving unit 12C has received a reflected signal even after a time D3 has elapsed since the transmitting unit 11A transmitted a transmission signal. In the example shown in FIG. 5, the reflected signal is a reflected signal generated when the transmission signal transmitted by the transmitting unit 11A is reflected by the subject U3.

[0070] Similarly, the measurement unit 156 measures that the reception unit 12A receives a reflected signal after a time period D4 has elapsed since the transmission unit 11B transmitted a transmission signal. In the example shown in FIG. 5, the reflected signal is a reflected signal generated when the transmission signal transmitted by the transmission unit 11B is reflected by the subject U4.

[0071] The measuring section 156 repeats the same process even after time T4. As shown in Fig. 7, the propagation time from when the transmitter 11 transmits a transmission signal to when the receiver 12 receives a reflected signal changes from D1 to D4 to D1' to D4'. This is because the part of the subject U1 to subject U4 that reflected the transmission signal has moved, causing a change in the distance between the part and the biological state measuring device 1.

[0072] The measuring unit 156 may further measure the intensity of the reflected signal received by the receiving unit 12, and store the measured intensity of the reflected signal together with the propagation time in the memory unit 14. Since the amount of signal attenuation varies depending on the distance between the biological state measuring device 1 and the subject U, it is considered that the intensity of the reflected signal decreases as the propagation time increases, as shown in FIG. 7. When the intensity of a reflected signal with a long propagation time is greater than the intensity of a reflected signal with a short propagation time, the measuring unit 156 may determine that the reflected signal may contain noise, and may not store the propagation time of the reflected signal in the memory unit 14.

[0073] Based on the measured propagation time, the measurement unit 156 identifies the biological condition of each of the multiple subjects U. When the biological condition measuring device 1 has multiple transmitting units 11, the measurement unit 156 identifies the biological condition of the multiple subjects U who are within the range where the multiple transmitting units 11 transmit transmission signals. When the biological condition measuring device 1 has multiple receiving units 12, the measurement unit 156 identifies the biological condition of the multiple subjects U who are within the range where the multiple receiving units 12 receive reflected signals.

[0074] The measurement unit 156 identifies the biological condition of the subject U based on a change in the phase of the frequency component corresponding to the frequency stored in the storage unit 14. The measurement unit 156 first generates a phase signal by chronologically arranging phase data indicating the phase of the frequency component corresponding to the frequency selected by the frequency selection unit 155 over a frequency fixing period. Then, the measurement unit 156 identifies the biological condition based on the frequency component included in the period range or frequency range corresponding to the biological condition in the generated phase signal.

[0075] The measurement unit 156, for example, identifies the time interval of peaks in the phase signal to identify the respiration rate and the heart rate. When the time interval of the peaks is included in a range assumed as the period of the biological state to be identified, the measurement unit 156 identifies the identified time interval as the period of the biological state. The measurement unit 156 identifies the respiration rate per unit time based on the time interval of the peaks included in the range assumed as the period of the respiratory cycle. Similarly, the measurement unit 156 identifies the heart rate per unit time based on the time interval of the peaks included in the range assumed as the period of the heartbeat. The range assumed as the period of the respiratory cycle is, for example, from 3 seconds to 6 seconds, and the range assumed as the period of the heartbeat is, for example, from 0.5 seconds to 1 second.

[0076] The measuring unit 156 may convert the signal generated by arranging the phases of the frequency components corresponding to the frequencies selected by the frequency selecting unit 155 in a time series into the frequency domain by FFT processing, and separate the signal into frequency components included in the respiratory frequency band and frequency components included in the heartbeat frequency band by a bandpass filter. The respiratory frequency band corresponds to a range expected as the frequency of the respiratory cycle (i.e., the inverse of the cycle), for example, 0.167 Hz to 0.333 Hz (corresponding to a respiratory rate of 10 to 20 times per minute). The heartbeat frequency band corresponds to a range expected as the frequency of the heartbeat (i.e., the inverse of the cycle), for example, 1 Hz to 2 Hz (heartbeat rate of 60 to 120 times per minute). These values ​​are stored in the storage unit 14, for example, when the operation receiving unit 151 receives the settings.

[0077] The measurement unit 156 identifies, as the respiratory frequency, a frequency component having an intensity equal to or greater than a first intensity (e.g., a frequency component having the maximum intensity) among a plurality of frequency components included in the respiratory frequency band. Similarly, the measurement unit 156 identifies, as the heartbeat frequency, a frequency component having an intensity equal to or greater than a second intensity (e.g., a frequency component having the maximum intensity) among a plurality of frequency components included in the heartbeat frequency band. The measurement unit 156 operates in this manner, thereby making it possible to identify the frequencies of the respiratory and heartbeat with high accuracy.

[0078] In addition, when the frequency selected by the frequency selection unit 155 is switched for each fixed frequency period, the time series data may change discontinuously before and after the frequency switching. In such a case, the measurement unit 156 may correct the phase signal so as to reduce the discontinuity of the phase signal based on the time series phase data at the timing of the frequency switching. For example, the measurement unit 156 corrects the value of the phase data within a predetermined range from the end of the time series phase data before the frequency switching and the value of the phase data within a predetermined range from the beginning of the time series phase data after the frequency switching, so that the phase signal changes continuously.

[0079] Since the intensity of the signal reflected by the heart is small, the measurement unit 156 may amplify the frequency components included in the heart rate frequency band. The measurement unit 156 may amplify the reflected signal with different amplification factors for the respiratory frequency band and the heart rate frequency band.

[0080] The measurement unit 156 may extract samples (M samples) for a certain period of time from a signal generated by arranging in time series the phases of frequency components corresponding to the frequencies selected by the frequency selection unit 155, and perform matching processing on the multiple samples to identify the period of the signal, thereby identifying the biological state. In the matching processing, the measurement unit 156 uses, for example, the sum of squared differences of multiple samples shifted by a predetermined sampling time as an evaluation value, and identifies the amount of shift when the evaluation value is minimized as the period of the signal.

[0081] The measurement unit 156 determines the heart rate based on the phase signal over a frequency fixed period, and determines the respiration rate based on the phase signal over a period that is 1.5 to 2.5 times the frequency fixed period. When the frequency fixed period is set to, for example, 5 to 10 seconds, the measurement unit 156 operates in this manner, so that the heart rate and respiration rate can be measured based on the phase signal over multiple cycles of the heartbeat and respiration, thereby improving the measurement accuracy.

[0082] When the biological condition measuring device 1 has multiple transmitting units 11 and multiple receiving units 12, the measuring unit 156 identifies the biological conditions of multiple subjects U in each of multiple ranges defined by combinations of ranges in which the multiple transmitting units 11 transmit transmitted signals and ranges in which the multiple receiving units 12 receive reflected signals, based on the propagation time measured for each combination of the transmitting units 11 and the receiving units 12. By configuring the biological condition measuring device 1 in this way, even if multiple subjects U are located at the same distance from the biological condition measuring device 1, the biological condition measuring device 1 can identify the biological condition of each of the subjects U.

[0083] To identify the biological conditions of the multiple subjects U, the measurement unit 156 first creates a waveform indicating the movement of the heart or a waveform indicating the movement of the pleura, etc., by identifying the change in distance between the biological condition measuring device 1 and the site that reflected the transmitted signal in each of the multiple subjects U, based on the change in the measured propagation time. The measurement unit 156 identifies the period of these waveforms, thereby identifying the biological conditions, such as the heart rate or respiratory rate per unit time.

[0084] 7, when a transmission signal is reflected by multiple subjects U, the receiving unit 12 receives multiple reflected signals based on one transmission signal. The measuring unit 156 performs the following process to identify the propagation time corresponding to each of the multiple subjects U.

[0085] First, the measurement unit 156 classifies the propagation time data indicating the measured propagation times into a plurality of time series data constituted by a plurality of propagation time data indicating propagation times varying within a time range equal to or less than a first threshold value, and identifies the biological condition of each of the plurality of subjects U based on the change in propagation time at each time interval indicated by each of the plurality of time series data. The first threshold value is a value that is greater than the maximum amount of change in propagation time caused by the movement of the organs of one subject U and is smaller than the minimum value assumed as the difference in propagation time between the reflected signal from the other subjects U. The measurement unit 156 stores the identified biological condition in the storage unit 14 in association with the subject U.

[0086] The maximum value of the change in propagation time caused by the movement of the organs of the subject U corresponds to the maximum amount (e.g., 5 cm) that is assumed as the amount of displacement of the organ position when the subject U is stationary, and the difference in propagation time with reflected signals from other subjects U corresponds to a difference in distance of, for example, 50 cm. In other words, the first threshold is the time required for radio waves to propagate any distance between 5 cm and less than 50 cm.

[0087] 7 shows a case where the difference in propagation time between a reflected signal with a delay time of D1 from time T1 and a reflected signal with a delay time of D1' from time T4, a predetermined time interval after time T1, is less than a first threshold value. The measuring unit 156 determines that these reflected signals are reflected signals corresponding to the same subject U. Also, FIG. 7 shows a case where the difference in propagation time between a reflected signal with a delay time of D1 from time T1 and a reflected signal with a delay time of D2' from time T4 is equal to or greater than the first threshold value. The measuring unit 156 determines that these reflected signals are reflected signals corresponding to different subjects U.

[0088] FIG. 8 is a diagram for explaining the operation of the measuring unit 156. The horizontal axis of FIG. 8 is time, and the vertical axis is the propagation time of the reflected signal measured by the measuring unit 156 at each time. The fluctuation in the propagation time is equivalent to the fluctuation in the phase of the reflected signal. The black circles in FIG. 8 are the propagation times of the reflected signal corresponding to the measured person U1, and the white circles are the propagation times of the reflected signal corresponding to the measured person U2. The fluctuation range within one period of the multiple propagation times indicated by the black circles is Δt1, and the fluctuation range within one period of the multiple propagation times indicated by the white circles is Δt2, which are less than the first threshold value. On the other hand, the minimum value ΔT of the difference between the propagation times indicated by the black circles and the propagation times indicated by the white circles is equal to or greater than the first threshold value.

[0089] The propagation time of the reflected signal corresponding to the subject U1 is the time from when the component of the first frequency included in the transmission signal is transmitted by the transmitting unit 11 until the receiving unit 12 receives the component of the first frequency included in the reflected signal. The propagation time of the reflected signal corresponding to the subject U2 is the time from when the component of the second frequency included in the transmission signal is transmitted by the transmitting unit 11 until the receiving unit 12 receives the component of the second frequency included in the reflected signal.

[0090] The measurement unit 156 classifies the multiple propagation time data into first time series data corresponding to the multiple propagation times indicated by black circles and second time series data corresponding to the multiple propagation times indicated by white circles. Then, the measurement unit 156 identifies the biological condition of the subject U1 based on the first time series data, and identifies the biological condition of the subject U2 based on the second time series data. By operating the measurement unit 156 in this manner, the measurement unit 156 can identify the biological condition of each of the multiple subjects U even when the reception unit 12 receives multiple reflected signals based on a transmission signal transmitted by one transmission unit 11.

[0091] After identifying the biological conditions of the multiple subjects U, the measurement unit 156 may track the biological conditions of the moving subjects U based on the magnitude of the propagation time. The measurement unit 156 identifies time series data consisting of multiple propagation time data indicating propagation times that vary within a time range equal to or less than a second threshold value that is greater than the first threshold value within a period in which the propagation time varies as the biological condition of one subject U, and stores the identified biological condition in the storage unit 14 in association with the subject U. The second threshold value is a value that is greater than the maximum amount of change in propagation time within a predetermined time period (e.g., within one period in which the propagation time varies) caused by the movement of one subject U, and is smaller than the difference in propagation time between the reflected signals from the other subjects U.

[0092] Fig. 9 is a diagram for explaining the process in which the measurement unit 156 tracks the biological condition of the subject U. As in Fig. 8, the black circles in Fig. 9 represent the propagation times of the reflected signals corresponding to the subject U1, and the white circles represent the propagation times of the reflected signals corresponding to the subject U2.

[0093] 9, subject U1 and subject U2 are moving, and the propagation time changes over time. Specifically, subject U1 is moving away from biological state measuring device 1 over time, and subject U2 is moving toward biological state measuring device 1 over time. The measuring unit 156 selects, from among the multiple propagation time data, multiple propagation time data that indicate propagation times with a fluctuation range equal to or less than a second threshold for each propagation time fluctuation period, thereby identifying first time series data corresponding to subject U1 shown in black and second time series data corresponding to subject U2 shown in white.

[0094] Since the measurement section 156 creates the first time series data based on the first frequency component and creates the second time series data based on the second frequency component, the first time series data and the second time series data can be separated even at a time when the positions of the subject U1 and the subject U2 are approximately the same.

[0095] However, as a result of the frequency selection unit 155 reselecting the frequency, there is a case where the frequency corresponding to the subject U1 is changed from the first frequency to the second frequency, and the frequency corresponding to the subject U2 is changed from the second frequency to the first frequency. In such a case, at the time when the positions of the subjects U1 and U2 are almost the same, the measurement unit 156 may identify the propagation time data corresponding to each subject U based on the characteristics (e.g., intensity or period) of the waveform when the propagation time data before and after are combined. Specifically, the measurement unit 156 assumes that the propagation time data that is unknown to which subject U corresponds to is the propagation time data of one of the subjects U, and identifies the characteristics of the waveform of the period including the propagation time data. If the identified characteristics match the characteristics of the past period, the measurement unit 156 determines that the assumption is correct, and if they do not match, the measurement unit 156 determines that the assumption is incorrect and identifies that the propagation time data corresponds to another subject U.

[0096] The measurement unit 156 may identify biological conditions corresponding to each of a plurality of parts of the subject U. The measurement unit 156 identifies the parts based on the propagation times of different frequency components included in a plurality of reflected signals generated by reflection of a transmission signal at a plurality of parts, such as the movement of the heart, the movement of the carotid artery, the movement of the pleura, or the movement of the head of the subject U. The measurement unit 156 classifies a plurality of reflected signals generated by reflection of a single transmission signal transmitted by the transmission unit 11 at a plurality of parts of the subject U, based on a combination of a range including the propagation time measured by the measurement unit 156 and a frequency selected by the frequency selection unit 155, thereby identifying a plurality of biological conditions corresponding to a plurality of parts. By operating in this manner, the measurement unit 156 can identify a plurality of biological conditions of the subject U even if the difference in propagation time between the plurality of parts is small.

[0097] The measuring unit 156 may identify the positions of multiple subjects U. Specifically, the measuring unit 156 identifies the position of the subject U who emitted the reflected signal based on the range in which the receiving unit 12 that received the reflected signal receives the reflected signal, the range in which the transmitting unit 11 that transmitted the transmission signal that generates the reflected signal transmits the transmission signal, and the distance to the subject U corresponding to the propagation time.

[0098] 5(a), the transmission signal transmitted by the transmitter 11A is reflected by the subjects U1, U2, and U3, and the transmission signal transmitted by the transmitter 11B is reflected by the subject U4. The reflected signals reflected by the subjects U1, U2, and U4 are received by the receiver 12A, and the reflected signal reflected by the subject U3 is received by the receiver 12C.

[0099] When the receiver 12A receives a reflected signal based on the transmission signal transmitted by the transmitter 11A, the measurement unit 156 determines that the subjects U1 and U2 who reflected the transmission signal are in an area where the transmission range of the transmitter 11A and the reception range of the receiver 12A overlap. When the receiver 12C receives a reflected signal based on the transmission signal transmitted by the transmitter 11A, the measurement unit 156 determines that the subject U3 who reflected the transmission signal is in an area where the transmission range of the transmitter 11A and the reception range of the receiver 12C overlap.

[0100] The measuring unit 156 further specifies the distance between the biological state measuring device 1 and the subject U based on the magnitude of the propagation time. The measuring unit 156 can specify the positions of multiple subjects U relative to the biological state measuring device 1 based on the area in which the subjects U are present and the distance from the biological state measuring device 1 to the subjects U.

[0101] The output unit 155 outputs information indicating the position of the subject U identified by the measurement unit 156 in association with the biological condition. Specifically, the output unit 155 causes the information terminal 2 to display a screen indicating the biological condition shown in Fig. 2 and a screen indicating the position of the subject U shown in Fig. 3, outputs these data to a printer, and transmits them to an external device via a communication line.

[0102] 2, the output unit 155 outputs the biological state corresponding to the subject U identified as being closest to the biological state measuring device 1 based on the propagation time, among the multiple biological states corresponding to the multiple subjects U identified by the measurement unit 156, in preference to biological states corresponding to the other subjects U. For example, the output unit 155 causes the information terminal 2 to display the biological states in order starting from the subject U closest to the biological state measuring device 1, or causes the information terminal 2 to display only the biological state of the subject U closest to the biological state measuring device 1. By the output unit 155 operating in this manner, when there are many people in a room in which the biological state measuring device 1 is used, the user can easily grasp the biological state of the subject U whose biological state is to be measured.

[0103] [Processing flow in biological state measuring device 1] Fig. 10 is a flowchart showing an outline of the flow of processing in the biological state measuring device 1. The flowchart shown in Fig. 10 starts at the point when the user of the biological state measuring device 1 performs an operation to start measurement.

[0104] The radio wave control unit 152 selects, based on time, from the multiple transmission units 11, a transmission unit 11 to be caused to transmit a transmission signal (S11). In the example shown in Fig. 7, the radio wave control unit 152 selects the transmission unit 11A at time T1. The radio wave control unit 152 causes the selected transmission unit 11 to transmit a transmission signal (S12).

[0105] Next, the receiver 12 receives a reflected signal based on the transmitted signal (S13). The measurement unit 156 calculates the propagation time required from when the transmitted signal is transmitted until the receiver 12 receives the reflected signal (S14). The measurement unit 156 stores the propagation time data in the storage unit 14 in association with the combination of the transmitter 11 that transmitted the transmitted signal and the receiver 12 that received the reflected signal (S15).

[0106] The radio wave control unit 152 determines whether the next transmission timing (for example, time T2) has arrived (S16). If the radio wave control unit 152 determines that the next transmission timing has not arrived (NO in S16), the radio wave control unit 152 does not cause the transmission unit 11 to transmit a transmission signal, and the processes from S13 to S16 are repeated.

[0107] When the radio wave control unit 152 judges that the next transmission timing has come (YES in S16), the measurement unit 156 judges whether or not a predetermined time has elapsed since the transmission unit 11 started transmitting a transmission signal and it is time to identify the biological condition (S17). The predetermined time is the time until the measurement unit 156 stores a number of propagation time data required to identify the biological condition. The predetermined time is a frequency fixed period longer than one cycle of the biological condition, for example, 5 seconds or more.

[0108] If the measurement unit 156 determines that the predetermined time has not elapsed (NO in S17), the radio wave control unit 152 selects the next transmission unit 11 (S11), and the processes from S11 to S17 are repeated. If the measurement unit 156 determines that the predetermined time has elapsed (YES in S17), the measurement unit 156 identifies the biological condition based on the propagation time data stored in the storage unit 14 (S18). The output unit 155 outputs the biological condition identified by the measurement unit 156 (S19). The biological condition measuring device 1 repeats the processes from S11 to S20 until the operation reception unit 151 receives an end operation (NO in S20).

[0109] Fig. 11 is a flowchart showing details of the process of analyzing a reflected signal in the biological state measuring device 1. The flowchart shown in Fig. 11 starts from the point in time when the receiving section 12 receives a reflected signal (S13 in Fig. 10).

[0110] When the receiver 12 receives the reflected signal, the signal converter 154 converts the reflected signal into the frequency domain by FFT (S21). Then, the frequency selector 155 determines whether it is time to select the frequency of the frequency component to be analyzed (S22). That is, the frequency selector 155 determines whether a frequency fixing period has elapsed since the previous frequency was selected again.

[0111] When it is determined that it is time to select frequencies (YES in S22), the frequency selection unit 155 selects a predetermined number of frequencies based on the intensities (i.e., amplitudes or powers) of the multiple frequency components (S23). The frequency selection unit 155 stores data indicating the selected frequencies in the storage unit 14 (S24).

[0112] Next, the measurement unit 156 identifies the phase of the frequency component of the selected frequency (S25). The measurement unit 156 associates the identified phase with a time and stores it in the storage unit 14 (S26). The measurement unit 156 repeats the processes of S25 and S26 until one frame period of the FFT ends (while NO is returned in S27).

[0113] When the frame period ends (YES in S27), the measurement unit 156 determines whether or not a predetermined time required to identify the biological condition has elapsed (S28). If the predetermined time has elapsed (YES in S28), the measurement unit 156 identifies the biological condition (S29). If the predetermined time has not elapsed (NO in S28), the measurement unit 156 returns the process to S22. The predetermined time is at least twice the maximum value assumed as the cycle of the biological condition, and when the biological condition is the respiratory rate, the predetermined time is, for example, at least 12 seconds (preferably 60 seconds), and when the biological condition is the heart rate, the predetermined time is, for example, at least 2 seconds (preferably 10 seconds).

[0114] The measurement unit 156 determines whether or not the operation receiving unit 151 has received an end operation (S30). If the end operation has not been performed (NO in S30), the measurement unit 156 returns the process to S22.

[0115] When the frequency selection unit 155 determines in S22 that it is not time to select a frequency (NO in S22), it identifies the selected frequency stored in the storage unit 14 in S24 (S31). The measurement unit 156 executes the processes from S25 to S29 by analyzing the frequency component corresponding to the selected frequency included in the reflected signal.

[0116] [Variations] In the above description, the biological state measuring device 1 identifies the biological states of multiple subjects U, but some of the functions of the control unit 15 of the biological state measuring device 1 in the above description may be realized by another information processing device (for example, a computer on the cloud). In other words, the biological state measuring device 1 and the other information processing device may work in cooperation with each other to function as a biological state measuring system.

[0117] 12 is a diagram showing the configuration of a biological state measuring system S2 according to a modified example. The biological state measuring device 1 of the biological state measuring system S2 sequentially transmits the received reflected signals to an external server 3. In this case, the external server 3 executes at least some of the functions of the signal acquiring unit 153, the signal converting unit 154, the frequency selecting unit 155, and the measuring unit 156. Specifically, the external server 3 classifies the reflected signals of each of the multiple subjects U, identifies the biological state based on the propagation time, and transmits the identified result to an arbitrary terminal.

[0118] The biological state measuring device 1 may transmit data of the frequency component corresponding to the frequency selected by the frequency selecting section 155 to an external server 3, and the server 3 may execute the processing of the measuring section 156. Furthermore, the biological state measuring device 1 may transmit to the server 3 only data of the frequency component contained in the reflected signal received by the receiving section 12 corresponding to the position where the presence of the subject U is detected. With this configuration, it is possible to reduce the amount of data transmitted to the server 3 and the amount of calculation in the server 3.

[0119] The external server 3 may receive reflected signals from the multiple biological state measuring devices 1 and identify the biological states of the multiple subjects U corresponding to the reflected signals received by the multiple biological state measuring devices 1. This configuration is suitable for the case where a large number of subjects U are present in multiple rooms.

[0120] [Effects of biological condition measuring device 1] As described above, the frequency selection unit 155 selects a frequency at which the intensities of the multiple frequency components corresponding to the multiple frequencies included in the reflected signal are relatively large every time the frequency fixing time elapses. The measurement unit 156 can measure the biological condition of the subject U, such as the heart rate or respiratory rate, while suppressing the amount of calculation by identifying the fluctuation period of the phase of the frequency components of the selected frequency in the reflected signal.

[0121] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0122] 1. Biological condition measuring device 2. Information terminal 3 Server 11 Transmitter 12 Receiving section 13 External connection part 14 Storage section 15 Control section 151 Operation reception section 152 Radio Control Unit 153 Signal Acquisition Unit 154 Signal conversion unit 155 Frequency Selection Unit 156 Measuring section

Claims

1. An ecological condition measuring device for measuring the biological condition of a subject, comprising: a signal acquisition unit that acquires a reflected signal generated when a chirp signal in a frequency band equal to or higher than the millimeter wave band transmitted at each predetermined frame time is reflected from the subject; a signal conversion unit that converts the reflected signal into a complex signal in a frequency domain for each frame time; a frequency selection unit that selects a frequency corresponding to a frequency component having a relatively large intensity from among a plurality of frequency components included in the complex signal; a measuring unit that identifies the biological condition of the subject based on a change in the phase of the frequency component corresponding to the frequency selected by the frequency selecting unit over a frequency fixed period that is longer than a cycle in which the biological condition fluctuates; A biological condition measuring device having the same.

2. the measurement unit generates a phase signal by arranging the phases of the frequency components in time series over the frequency fixed period, and identifies the biological condition based on frequency components in the phase signal that are included in a period range or a frequency range corresponding to the biological condition. The biological condition measuring device according to claim 1 .

3. When a time interval between peaks in the phase signal is included in a range assumed as a period of the biological state to be identified, the measurement unit identifies the time interval as the period of the biological state. The biological condition measuring device according to claim 2 .

4. the measurement unit transforms the phase signal into a frequency domain, and identifies, as a respiratory frequency, a frequency component having a first intensity or higher among a plurality of frequency components included in a respiratory frequency band, and identifies, as a heartbeat frequency, a frequency component having a second intensity or higher among a plurality of frequency components included in a heartbeat frequency band; The biological condition measuring device according to claim 2 .

5. the measurement unit determines a heart rate based on the phase signal over the frequency fixed period, and determines a respiratory rate based on the phase signal over a period that is 1.5 times or more and 2.5 times or less than the frequency fixed period. The biological condition measuring device according to claim 2 .

6. The frequency fixing period is 5 seconds or more and less than 10 seconds. The biological condition measuring device according to claim 5 .

7. the measurement unit corrects the phase signal so as to reduce discontinuity in the phase signal at a timing when the frequency selected by the frequency selection unit is switched. The biological condition measuring device according to claim 2 .

8. the frequency selection unit selects a frequency corresponding to a frequency component having a relatively large intensity for each frequency fixing period. The biological condition measuring device according to claim 1 .

9. the frequency selection unit selects a frequency corresponding to a frequency component with the greatest intensity from among the plurality of frequency components. The biological condition measuring device according to claim 1 .

10. the signal acquiring unit acquires the reflected signals generated by reflection from the plurality of subjects; the frequency selection unit selects, from the plurality of frequency components, frequencies corresponding to frequency components whose number corresponds to the number of the subjects. The biological condition measuring device according to claim 1 .

11. further comprising a storage unit that stores frequencies corresponding to the frequency components selected by the frequency selection unit; the measurement unit identifies the biological condition of the subject based on a change in the phase of the frequency component corresponding to the frequency stored in the storage unit. The biological condition measuring device according to claim 1 .

12. A computer-implemented method for measuring a biological condition of a subject, comprising: acquiring a reflected signal generated when a chirp signal in a frequency band equal to or higher than the millimeter wave band transmitted at each predetermined frame time is reflected from the subject; a signal conversion unit that converts the reflected signal into a complex signal in a frequency domain for each frame time; selecting a frequency corresponding to a frequency component having a relatively large intensity from among a plurality of frequency components included in the complex signal; identifying the biological condition of the subject based on a change in phase of the frequency component corresponding to a selected frequency over a fixed frequency period longer than a cycle in which the biological condition fluctuates; A biological condition measuring method comprising:

13. A program for causing a computer to measure a biological condition of a subject, acquiring a reflected signal generated when a chirp signal in a frequency band equal to or higher than the millimeter wave band transmitted at each predetermined frame time is reflected from the subject; a signal conversion unit that converts the reflected signal into a complex signal in a frequency domain for each frame time; selecting a frequency corresponding to a frequency component having a relatively large intensity from among a plurality of frequency components included in the complex signal; identifying the biological condition of the subject based on a change in phase of the frequency component corresponding to a selected frequency over a fixed frequency period longer than a cycle in which the biological condition fluctuates; A program to execute.

14. A biological condition measuring device for measuring the biological condition of a subject, and an external device capable of communicating with the biological condition measuring device, the biological state measuring device has a signal acquiring unit that acquires a reflected signal generated when a chirp signal in a frequency band equal to or higher than the millimeter wave band, which is transmitted at each predetermined frame time, is reflected from the subject; The biological state measuring device or the external device is a signal conversion unit that converts the reflected signal into a complex signal in a frequency domain for each frame time; a frequency selection unit that selects a frequency corresponding to a frequency component having a relatively large intensity from among a plurality of frequency components included in the complex signal; a measuring unit that identifies the biological condition of the subject based on a change in the phase of the frequency component corresponding to the frequency selected by the frequency selecting unit over a frequency fixed period that is longer than a cycle in which the biological condition fluctuates; having Biological status measurement system.

Images