JP7099353B2 - Biological information measurement system - Google Patents

Description

The present invention relates to a biological information measurement system.

Conventionally, in medical institutions such as hospitals, a system for continuously measuring biological information such as a patient's respiratory rate, respiratory waveform, heart rate, and heart rate waveform using a radio wave sensor and monitoring the presence or absence of an abnormality has been used. ing. In this system, by displaying the measurement data of biological information on a terminal device provided on the bedside, a medical worker such as a doctor or a nurse can confirm the measurement data.
It has been proposed that the sensor should be installed next to or directly under the mat (see, for example, Patent Document 1).

By the way, in recent years, in order to prevent pressure sores (bedsores) in patients without the work of nurses / caregivers, there has been an opportunity to use an electric air mattress that periodically moves the contact area with the human body by expanding and contracting. It has increased.

International Publication No. 2017/130646

However, when the above air mattress is used, the operation of the air mattress may affect the measured value of the sensor. In particular, when the sensor is installed directly under the mat as in Patent Document 1, it is directly affected by the air mat, and the measured value is likely to be affected.
Further, when the sensor is installed next to the mat as in Patent Document 1, the entire sensor protrudes from the mat, which hinders the behavior of medical staff and patients, and causes a problem in operability. Also, in order to attach the sensor to the side of the mat so that it does not interfere with the movement, for example, it is necessary to fix it to the fence next to the bed, but since the fence next to it is frequently removed, this is also a problem for operability. There is.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a biological information measurement system having good operability and capable of reducing the influence of the operation of an air mattress.

In order to solve the above problems, the biological information measurement system of the present invention is used.
An air mat that moves up and down due to expansion or contraction due to air supply and exhaust,
A radio wave sensor that irradiates a living body on the air mat with radio waves and detects the movement of the living body using the reflected waves.
An arithmetic processing unit that acquires biological information of a living body on the air mattress from a detection signal output from the radio wave sensor.
Equipped with
The radio wave sensor is located below the air mattress at a position where at least a part thereof overlaps the lower surface of the edge portion of the air mattress, and the directivity of the radio wave radiated from the radio wave sensor faces the center of the upper surface of the air mattress. It is characterized in that it is arranged in such a manner.

According to the present invention, it is possible to provide a biological information measurement system having good operability and capable of reducing the influence of the operation of the air mattress.

It is a schematic diagram which shows the structure of the biological information measurement system of 1st Embodiment. It is a block diagram which shows the functional structure of the biological information measurement system of FIG. It is an external view of a radio wave sensor. It is sectional drawing in the IV line of FIG. It is a figure for demonstrating the arrangement of a radio wave sensor. It is a figure for demonstrating the configuration of a radio wave sensor. It is a figure for demonstrating the noise reduction processing using an adaptive noise canceling mechanism. It is a figure for demonstrating the noise reduction processing using a power spectrum. It is a figure which shows the arrangement example of the radio wave sensor which forms a pair of 2nd Embodiment. It is a figure for demonstrating the signal processing in 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

<First Embodiment>
[Configuration of biometric information measurement system]
First, the configuration of the biological information measurement system 100 of the present embodiment will be described.

FIG. 1 is a conceptual diagram showing the configuration of the biological information measurement system 100. FIG. 2 is a block diagram showing a functional configuration of the biological information measurement system 100.
As shown in FIGS. 1 and 2, the biological information measurement system 100 obtains biological information from, for example, an air mat device 10, a radio wave sensor 20 disposed in the air mat device 10, and a detection signal of the radio wave sensor 20. It is configured to include a device (calculation processing unit) 30 and a display device 40 for displaying the calculation result by the calculation device 30.
Although the arithmetic unit 30 and the display device 40 are separate bodies here, they may be integrated.

[Air mattress device]
The air mattress device 10 is a bed device that is installed in, for example, a hospital room and in which a patient who is a user lies down. The air mattress device may be a cushion device on which the patient sits.

The air mat device 10 includes a bed frame 11 and an air mat 12.

The bed frame 11 includes a floor plate 11a, a headboard 11b surrounding the floor plate 11a, a footboard 11c, and fences 11d and 11d.
The floor plate 11a is a rectangular plate on which the air mat 12 is placed. A headboard 11b and a footboard 11c are erected at both ends of the floor plate 11a in the longitudinal direction. Further, removable fence bodies 11d and 11d are erected on both sides of the floor plate 11a in the lateral direction.

The air mat 12 is a so-called air mattress that has a plurality of air cells 12a and can support the load of a patient lying down on the air mat 12 by filling the inside of the air cells 12a with air. The plurality of air cells 12a form, for example, the air mattress 12 by being juxtaposed in the longitudinal direction of the air mattress 12. The air cells 12a arranged adjacent to each other may or may not be fixed to each other.

The plurality of air cells 12a are divided into a plurality of groups. By alternately expanding or contracting the air cells 12a of each group at regular intervals, the air cells 12a supporting the patient can be switched at regular intervals to partially change the thickness of the air mattress 12. Further, the thickness of the air mat 12 can be changed as a whole by simultaneously expanding or contracting all the air cells 12a at regular intervals. Due to such expansion or contraction, the air mat 12 moves up and down.
The vertical movement of the air mattress prevents the repulsive force from the air mattress from being continuously applied to the same part of the patient's body for a long time, and the same pressure is applied to a specific part of the patient's body for a long time to cause pressure sores (bedsores). ) Can be prevented, an effect of preventing stuffiness, an effect of facilitating getting out of bed, and the like can be obtained.

Further, the air mat 12 includes an air supply / exhaust unit 13 and a mat control unit 14.
The air supply / exhaust unit 13 includes, for example, a pump 13a that supplies air to the air cell 12a, an exhaust valve 13b that exhausts air from the air cell 12a, and a connection path that separately connects the air cell 12a, the pump 13a, and the exhaust valve 13b. , Etc. are provided.
The mat control unit 14 measures the internal pressure of the air cell 12a by a measurement unit (not shown), outputs an ON / OFF signal based on the measurement result, and controls the pump 13a and the exhaust valve 13b.

[Radio wave sensor]
The radio wave sensor 20 is a sensor capable of detecting the movement of the patient without contacting the patient by irradiating the patient to be measured with a radio wave and detecting the reflected wave.
Specifically, examples of the radio wave sensor 20 include sensors such as Doppler, FMCW, and pulse Doppler.
The radio wave sensor 20 irradiates the patient with microwaves and detects the movement of the patient by the change in the frequency of the reflected microwaves. That is, when the patient is moving, the frequency of the reflected wave changes due to the Doppler effect, and this frequency change is detected and the detection signal is output. When the patient is not moving (including the case where there is no patient), the frequency does not change and the detection signal without change is output.

FIG. 3 is an external view of the radio wave sensor 20. Further, FIG. 4 is a cross-sectional view taken along the line IV of FIG.
As shown in FIGS. 3 and 4, the radio wave sensor 20 includes a housing 21 having an accommodation space inside. The housing 21 includes a flat main body portion 211 and a protruding portion 212 protruding upward at one end in the longitudinal direction of the main body portion 211.

Inside the housing 21, an antenna 22, a main board 23 having a radio wave detection circuit, a communication connector 25 connected to a communication cable 24, a holding member 26 for integrally holding these, and the like are housed.
The antenna 22 transmits a transmission signal output from the radio wave detection circuit as a radio wave having a predetermined frequency. Further, the antenna 22 receives a radio wave (reflected wave) that is reflected and returned to the patient (living body) among the transmitted radio waves, and outputs a received signal.
The radio wave detection circuit generates a transmission signal having a predetermined frequency, outputs the generated transmission signal to the antenna 22, and detects the radio wave received by the antenna 22.

The radio wave sensor 20 is arranged below the air mattress 12 at a position where at least a part thereof overlaps the lower surface of the edge portion of the air mattress 12. That is, as shown in FIG. 1, the radio wave sensor 20 is arranged so as to be inserted between the air mat 12 and the floor plate 11a. The radio wave sensor 20 may be placed on the floor plate 11a, and the air mat 12 may be placed on the floor plate 11a.

Further, the directivity of the radio wave radiated from the antenna 22 of the radio wave sensor 20 is arranged so as to face the center of the upper surface of the air mat 12.
Specifically, when the antenna 22 is a patch antenna, the half-value width is about ± 30 degrees, and it is preferable that the patient is contained in this half-value width. For example, the antenna surface is relative to the main surface of the main board 23. It is installed at an angle of about 40 to 80 degrees.
At this time, as shown in FIG. 5, it is preferable that the direction in which the directivity of the radio wave radiated from the antenna 22 of the radio wave sensor 20 is maximized is adjusted to be different from the direction in which the air mattress 12 moves most. By doing so, it is possible to obtain a large signal value while reducing the influence of the vertical movement of the air mat 12, and it is possible to perform effective measurement.

The shape of the housing 21 is formed according to the installation angle of the antenna 22, and the main board 23, the communication connector 25, and the like are housed inside the main body 211, and the protruding portion 212 is accommodated. The antenna 22 will be housed inside the.
Then, it is inserted from the main body portion 211 of the radio wave sensor 20 below the air mattress 12 (between the air mattress 12 and the floor plate 11a) and arranged at a predetermined position. From the viewpoint of improving operability, it is preferable that the entire radio wave sensor 20 is positioned so as to overlap the lower surface of the edge portion of the air mattress 12, but as shown in FIG. 1, a part of the radio wave sensor 20 is a part of the air mattress 12. It may protrude outward from the edge of the.

Further, in the state where the radio wave sensor 20 is arranged as described above, the height of the radio wave sensor 20 (height of the protruding portion 212) is preferably equal to or less than the thickness of the air mat 12. By doing so, it is possible to prevent the patient from being uncomfortable due to the unevenness of the air mat 12 due to the installation of the radio wave sensor 20.

When the antenna 22 is an array antenna whose directivity can be controlled, the antenna 22 may be configured not to be tilted with respect to the main board 23. In this case, the entire radio wave sensor 20 is formed in a flat shape, and the entire radio wave sensor 20 is inserted below the air mattress 12 (between the air mattress 12 and the floor plate 11a) and arranged at a position overlapping the lower surface of the edge portion of the air mattress 12. Will be set up.

FIG. 6 is a diagram for further explaining the configuration of the radio wave sensor 20.
As shown in FIG. 6, the back surface of the protrusion 212 of the housing 21 is open, and this opening is closed by the holding member 26 housed inside the housing 21, and the protrusion 212 is closed as needed. It is also preferable that the holding member 26 can be pulled out from the opening on the back surface.
By doing so, it is possible to replace and maintain the internal parts of the radio wave sensor 20 even when the patient lies on the air mat 12 and the radio wave sensor 20 is still installed.

Further, in the present embodiment, the pressure sensor 50 is provided between the air mat 12 and the floor plate 11a.
The pressure sensor 50 is arranged at a position that does not overlap the patient's body as much as possible (for example, under the corner of the air mat 12).

[Arithmetic logic unit]
The arithmetic unit 30 includes, for example, a CPU (Central Processing Unit), a storage device that stores a control program and control data, and a memory in which the CPU expands the data.
The arithmetic unit 30 performs a calculation by processing the detection signal output from the radio wave sensor 20 by executing the control program by the CPU.

[Display device]
The display device 40 is, for example, a device provided on the bedside of the patient and displaying the calculation result by the calculation device 30. The display device 40 may be, for example, a monitoring device provided in a nurse station or a mobile terminal device carried by a medical worker such as a doctor or a nurse.
The display device 40 is configured to include, for example, an LCD (Liquid Crystal Display) or the like, and displays various screens according to instructions of a display signal input from the arithmetic unit 30.
The display device 40 can switch and display a plurality of screens including a screen for displaying biological information (measured values, measured waveforms, etc.).

[Signal processing by arithmetic unit]
Next, signal processing by the arithmetic unit 30 of the biological information measurement system 100 will be described.

In the present embodiment, the arithmetic unit 30 calculates biological information based on the detection signal output from the radio wave sensor 20 and the reference signal indicating the operation of the air mattress 12.

Specifically, when the detection signal is output from the radio wave sensor 20, the arithmetic unit 30 converts the detection signal into a distance signal or a speed signal.
For example, in order to obtain the distance signal from the detection signal (IQ signal) of the radio wave sensor 20, the following equation (1) can be used. Here, the angle θ becomes a distance signal.
θ = arctan (Q / I) ... (1)

Further, the arithmetic unit 30 acquires a reference signal from the pressure sensor 50.
Here, the reference signal is a signal indicating a pressure change due to the movement of the air mat 12 detected by the pressure sensor 50.
By arranging the pressure sensor 50 at a position that does not overlap the patient's body as much as possible, a reference signal indicating only the movement of the air mat 12 without being affected by the movement of the patient is generated.

Next, the arithmetic unit 30 performs noise reduction processing for subtracting a component of the reference signal from the distance signal or the speed signal.
As the noise removal process, a method using an adaptive noise canceling mechanism, a method using a power spectrum, or the like is used.

FIG. 7 is a diagram for explaining a noise reduction process using an adaptive noise canceling mechanism.
As shown in FIG. 7, the adaptive noise canceling mechanism outputs a signal in which the operation (noise) of the air mattress 12 is suppressed by using an adaptive filter.
Specifically, an input signal obtained by converting the detection signal (IQ signal) of the radio wave sensor 20 into a distance signal or a speed signal is input to the adaptive noise canceling mechanism. Such an input signal includes a noise signal caused by the operation of the air mat 12 in addition to a biological signal caused by the movement of the patient. Then, the frequency region (noise signal caused by the operation of the air mat 12) of the undesired portion is filtered from the input signal by the adaptive filter, and the signal from which this noise signal is subtracted is output. Since this output signal is obtained by removing the noise signal from the input signal, its peak frequency can be estimated as biometric information (respiratory rate, etc.).

8 (a) to 8 (c) are diagrams for explaining a noise reduction process using a power spectrum.
As shown in FIG. 8A, the input signal obtained by converting the detection signal (IQ signal) of the radio wave sensor 20 into a distance signal or a speed signal is subjected to FFT and power conversion such as Fourier transform to obtain a power spectrum. ..
Similarly, as shown in FIG. 8B, the power spectrum of the reference signal is also obtained. It is preferable that the maximum value of the peak frequency of the reference signal is normalized so as to be the same as the value of the same frequency of the input signal.
Then, the power spectrum of the reference signal is subtracted from the power spectrum of the detection signal of the radio wave sensor 20 to obtain a power spectrum from which noise has been removed as shown in FIG. 8 (c). The peak frequency of the power spectrum of FIG. 8 (c) is biological information (respiratory rate, etc.).

As the reference signal, the moving distance of the air mattress 12 in the thickness direction, the moving speed of the air mattress 12 in the thickness direction, and the like can also be used. In this case, a distance sensor or a speed sensor may be used instead of the pressure sensor 50. As the distance sensor and the speed sensor, a sensor using a radio wave, a laser, an ultrasonic wave, or the like is used.

[Effects of embodiments]
As described above, according to the present embodiment, the biological information measurement system 100 radiates radio waves to the air mat 12 that moves up and down due to expansion or contraction due to air supply / exhaust and the patient on the air mat 12, and the reflected wave thereof. The radio wave sensor 20 includes a radio wave sensor 20 that detects the movement of the living body by using the radio wave sensor 20, and a calculation device 30 that acquires the biometric information of the patient on the air mat 12 from the detection signal output from the radio wave sensor 20. Arranged below the air mat 12 at a position where at least a part overlaps the lower surface of the edge portion of the air mat 12 so that the directivity of the radio wave radiated from the radio wave sensor 20 faces the center of the upper surface of the air mat 12. Will be done.
Therefore, since the radio wave sensor 20 is located below the air mat 12 and at least a part thereof overlaps the lower surface of the edge of the air mat 12, it can be operated without disturbing the behavior of the medical staff or the patient. The sex can be improved.
Further, since the radio wave sensor 20 is located below the air mattress and at least a part thereof overlaps the lower surface of the edge portion of the air mattress 12, the air mattress is compared with the case where the sensor is installed directly under the air mattress, for example. It is not easily affected by 12 and can suppress the influence on the measured value.
Further, since it may be inserted between the air mat 12 and the support portion (here, the floor plate 11a) that supports the air mat 12 under the air mat 12, the installability can be improved.

Further, according to the present embodiment, the direction in which the directivity of the radio wave radiated from the radio wave sensor 20 is maximized is different from the direction in which the air mat 12 moves most.
Therefore, it is possible to obtain a large signal value while reducing the influence of the operation of the air mat 12, and effective measurement is possible.

Further, according to the present embodiment, the height of the radio wave sensor 20 when disposed with respect to the air mattress 12 is equal to or less than the thickness of the air mattress 12.
Therefore, it is possible to prevent the patient from being uncomfortable by installing the radio wave sensor 20.

Further, according to the present embodiment, the arithmetic unit 30 acquires biometric information based on the detection signal output from the radio wave sensor 20 and the reference signal indicating the operation of the air mattress 12.
Specifically, the arithmetic unit 30 acquires biometric information by subtracting a component of the reference signal from the detection signal output from the radio wave sensor 20.
Further, the reference signal is a signal indicating any one of the moving distance in the thickness direction of the air mattress 12, the moving speed in the thickness direction of the air mattress 12, and the pressure change due to the movement of the air mattress 12.
Therefore, more accurate measurement becomes possible.

As the reference signal, an ON / OFF signal of at least one of the pump 13a and the exhaust valve 13b of the air mattress 12 may be used.
In this case, when the arithmetic unit 30 determines from the reference signal that at least one of the pump 13a and the exhaust valve 13b of the air mattress 12 is operating, the arithmetic unit 30 acquires the detection signal (or the detection signal) output from the radio wave sensor 20. The biometric information provided) is judged to be invalid.

In the above embodiment, the number of radio wave sensors 20 is one, but a plurality of radio wave sensors 20 may be installed.
Further, in the above embodiment, the radio wave sensor 20 is arranged with respect to one side in the longitudinal direction of the air mattress 12, but may be arranged with respect to one side in the lateral direction of the air mattress 12. That is, it may be placed near the patient's head or feet.
Even in this case, the radio wave sensor 20 is located below the air mattress 12 at a position where at least a part thereof overlaps the lower surface of the edge portion of the air mattress 12, and the directivity of the radio wave is directed toward the center of the upper surface of the air mattress 12. It will be arranged like this.

Further, the operation information of the air mat 12 when there is no patient on the air mat 12 is measured and saved as a reference signal, and the saved operation information of the air mat 12 is obtained from the measured value of the radio wave sensor 20 when the patient is present. May be used to subtract the influence of the air mattress operation.

Further, the arithmetic unit 30 may acquire biometric information without performing processing using the above-mentioned reference signal.

<Second embodiment>
Next, the second embodiment of the present invention will be described focusing on the differences from the first embodiment. The same configurations as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

[Configuration of biometric information measurement system]
The biological information measurement system in the present embodiment includes a second radio wave sensor 60 in addition to the radio wave sensor 20.
The radio wave sensor 20 and the second radio wave sensor 60 form a pair, and the second radio wave sensor 60 is arranged so as to face the radio wave sensor 20 with the air mat 12 interposed therebetween.
The configuration of the second radio wave sensor 60 is the same as that of the radio wave sensor 20, but the frequencies of the generated radio waves are set to be different from each other.

9 (a) and 9 (b) are diagrams showing an example of the arrangement of the radio wave sensor 20 and the second radio wave sensor 60.
In FIG. 9A, one radio wave sensor 20 is arranged at a position where one of the radio wave sensors 20 overlaps the lower surface of the lower side of the air mattress 12 in the lateral direction (the edge on the foot side), and the other second radio wave sensor 60 has a second radio wave sensor 60. This is an example of the arrangement placed above the patient's head. The antenna surfaces of the two sensors 20 and 60 are installed so as to face each other.
Further, in FIG. 9B, one radio wave sensor 20 is arranged at a position where one of the radio wave sensors 20 overlaps the lower surface of one edge portion in the longitudinal direction of the air mattress, and the other second radio wave sensor 60 is the length of the air mattress 12. This is an example of being arranged at a position above the other edge in the direction. The antenna surfaces of the two sensors are installed so as to face each other.

[Signal processing by arithmetic unit]
In this case, as shown in FIG. 10, the arithmetic unit 30 obtains a synthetic signal from the distance or speed signal obtained from the detection signals of the paired radio wave sensors 20 and 60, and acquires biological information from the synthetic signal. The combined signal may be an additive value of two signals, or may be an average value of two signals.

As a result, for example, when the entire patient moves in the same direction, the increase / decrease in the distance or speed signal obtained from each of the paired radio wave sensors 20 and 60 is offset and synthesized because they move in the opposite direction. The signal becomes a signal from which the body movement component is removed (or reduced).
In addition, when the volume of the patient expands or contracts as in breathing, the increase / decrease of the distance or speed signal obtained from each of the paired radio wave sensors 20 and 60 moves in the same direction. It is more emphasized and the influence of noise can be reduced.
Further, even when the patient is biased on the air mat 12, the influence of the bias can be reduced in the synthesized signal by strengthening the signal of one of the paired radio wave sensors 20 and 60.

When the final biometric information is calculated by averaging after acquiring the biometric information (respiration rate and heart rate) of each sensor, the correlation between the distance or speed signals originally obtained from each sensor is obtained. Where the information is discarded, by doing the above, the information on the correlation of the phase information of each sensor can be effectively utilized, and the influence of disturbance such as body movement can be reduced.

[Effects of embodiments]
As described above, according to the present embodiment, the second radio wave sensor 60 is provided so as to face each other with the radio wave sensor 20 and the air mat 12 interposed therebetween, and the arithmetic unit 30 includes the radio wave sensor 20 and the second radio wave sensor 20. A synthetic signal is obtained from the distance or speed signal obtained from each detection signal of the radio wave sensor 60, and biological information is acquired from the synthetic signal.
Therefore, the influence of disturbance such as body movement can be reduced, and more accurate measurement becomes possible.

Of course, also in the present embodiment, the arithmetic processing using the reference signal may be performed as in the first embodiment.

Further, the pair of radio wave sensors is not limited to one set, and a plurality of sets may be provided. For example, the configuration may include a pair of both FIGS. 9 (a) and 9 (b).

The embodiments to which the present invention can be applied are not limited to the first and second embodiments described above, and can be appropriately changed without departing from the spirit of the present invention.

For example, in order to increase the reflectance of the radio wave sensor, a reflector (aluminum foil, a plate coated with aluminum foil, etc.) that reflects the radio wave of the sensor may be arranged on the upper surface of the air mat 12.

100 Biological information measurement system 10 Air mat device 11 Bed frame 11a Floor board 11b Headboard 11c Footboard 11d Fence body 12 Air mat 12a Air cell 13 Air supply / exhaust unit 13a Pump 13b Exhaust valve 14 Mat control unit 20 Radio wave sensor 21 Housing 211 Main body 212 Part 22 Antenna 23 Main board 24 Communication cable 25 Communication connector 26 Holding member 30 Calculation device (calculation processing unit)
40 Display device 50 Pressure sensor 60 Second radio wave sensor

Claims (9)

An air mat that moves up and down due to expansion or contraction due to air supply and exhaust,
A radio wave sensor that irradiates a living body on the air mat with radio waves and detects the movement of the living body using the reflected waves.
An arithmetic processing unit that acquires biological information of a living body on the air mattress from a detection signal output from the radio wave sensor.
Equipped with
The radio wave sensor is located below the air mattress at a position where at least a part thereof overlaps the lower surface of the edge portion of the air mattress, and the directivity of the radio wave radiated from the radio wave sensor faces the center of the upper surface of the air mattress. A biometric information measurement system characterized in that it is arranged in such a manner. The biometric information measurement system according to claim 1, wherein the direction in which the directivity of the radio wave radiated from the radio wave sensor is maximized is different from the direction in which the air mattress moves most. The biometric information measurement system according to claim 1 or 2, wherein the radio wave sensor has a height equal to or less than the thickness of the air mat when it is arranged with respect to the air mat. The arithmetic processing unit is
The biometric information measurement according to any one of claims 1 to 3, wherein the biometric information is acquired based on the detection signal output from the radio wave sensor and the reference signal indicating the operation of the air mattress. system. The biometric information measurement system according to claim 4, wherein the arithmetic processing unit acquires the biometric information by subtracting a component of the reference signal from the detection signal output from the radio wave sensor. The living body according to claim 4 or 5, wherein the reference signal is a signal indicating a moving distance in the thickness direction of the air mattress, a moving speed in the thickness direction of the air mattress, or a pressure change due to the movement of the air mattress. Information measurement system. The reference signal is an ON / OFF signal of at least one of the pump and the exhaust valve of the air mattress.
The calculation processing unit invalidates the detection signal output from the radio wave sensor when it is determined from the reference signal that at least one of the pump of the air mattress and the exhaust valve is operating. Item 4. The biometric information measurement system according to Item 4. A second radio wave sensor is provided so as to face the radio wave sensor with the air mattress in between.
The arithmetic processing unit obtains a synthetic signal from a distance or speed signal obtained from each detection signal of the radio wave sensor and the second radio wave sensor, and acquires the biological information from the synthetic signal. Item 6. The biometric information measurement system according to any one of Items 1 to 7. The biometric information measurement system according to claim 8, further comprising a plurality of pairs of the radio wave sensor and the second radio wave sensor.

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