JP2021023491A - Radio wave type moisture meter and biological information measurement device - Google Patents

Abstract

To provide a radio wave type moisture meter less likely to be affected by its surrounding factors such as vibration, and a biological information measurement device related with it.SOLUTION: The radio wave type moisture meter comprises: a radio transmission unit for transmitting a radio wave; a first radio reception unit and a second radio reception unit at least one of which receives a radio wave that has been transmitted by the radio transmission unit and has passed through a measurement target; a phase difference detection unit for detecting the phase difference between the radio waves received respectively by the first radio reception unit and the second radio reception unit; and a moisture detection unit for detecting the moisture content of the measurement target on the basis of the phase difference detected by the phase difference detection unit.SELECTED DRAWING: Figure 1B

Description

The present invention relates to a radio wave type moisture meter and a biological information measuring device.

In recent years, attention has been paid to a system that unconsciously measures biological information and manages health in daily life without invasiveness and without restraint.
In particular, unrestrained biometric information measurement technology is required for monitoring of elderly people during long-term care and monitoring of infants.
In addition, driver monitoring during autonomous driving is one of the important basic technologies for the realization of autonomous driving.
As a biological information measuring device, many types of measuring devices worn on the body such as a wristwatch have been developed.

However, in the type of measuring device worn on the body, it is troublesome to wear it on the body. In addition, it is not suitable for long-term monitoring because it requires battery operation. In addition, it is not suitable for use in systems that the operator may change at any time, such as driver monitoring, which is an elemental technology such as automatic driving / safe driving.
Currently, driver monitoring technologies include "contact-type sensor for measuring pressure fluctuation" (Patent Document 1), "Doppler-type sensor using microwave reflection" (Patent Document 2), and "capacitive coupling type". A method using electrodes ”(Non-Patent Document 1) has been proposed.
Further, as a moisture content sensor using a microwave (radio wave), a "microwave moisture meter" (Patent Document 3), a "microwave densitometer" (Patent Document 4), and the like have been proposed.

Japanese Unexamined Patent Publication No. 2018-23618 Publication of International Patent Application WO2013-118398 Japanese Unexamined Patent Publication No. 11-2236111 Japanese Unexamined Patent Publication No. 9-2435575

Makikawa et al., “Electrocardiogram measurement with non-grounded capacitively coupled electrodes,” Biomedical Engineering, 2006, Vol. 44, No. 1, p. 177-183.

All of the biometric information measurement technologies currently being researched and developed have the drawback of being vulnerable to noise caused by vibration from the road surface and acceleration / deceleration.
In the contact measurement technology disclosed in Patent Document 1 and the like, the contact pressure changes due to vibration, and the vibration of the noise source contains the same frequency components as the heartbeat and respiration, resulting in large noise and data processing. There is a limit to the noise removal by.

Similar to Patent Documents 2 to 4 and Non-Patent Document 1, sensors using microwave reflection, measurement methods using electrolytic resonance, methods using capacitive coupling electrodes, etc. also use biological information due to body vibration. There is a problem that a large noise is added to the signal such as.

An object of the present invention is to provide a radio wave type moisture meter which is not easily affected by ambient influences such as vibration and a biometric information measuring device related thereto.

The present invention has the following features.
1) The point that the transmission of radio waves was used for the measurement of biological information.
2) The point at which the amount of water is determined based on the phase difference of radio waves transmitted through parts with different transmittances.
3) The point of obtaining the time change of the water content based on the time change of the phase difference of the radio waves transmitted through the parts having different transmittances.
4) By considering the change in water content based on the change in received signal intensity in addition to the change in water content based on the phase difference, the change in water content can be estimated over a wide range of changes in water content.
5) By using multiple receiving antennas and measuring the phase difference between each receiving antenna and the difference in received signal intensity, the difference in radio wave transmittance depending on the part is estimated, and the water content of the part is sensed accurately. The point that can be done.

According to one aspect of the present invention, a first radio wave receiving unit that receives at least one of a radio wave transmitting unit that transmits radio waves and a transmitted wave that the radio waves transmitted from the radio wave transmitting unit have passed through a measurement target. And the second radio wave receiving unit, the phase difference detecting unit that detects the phase difference of the radio waves received by each of the first radio wave receiving unit and the second radio wave receiving unit, and the phase difference detecting unit detects. Provided is a radio wave type moisture meter having a moisture content detecting unit for detecting the moisture content of the measurement target based on the phase difference.

The transmitted wave of the radio wave is provided at a position where at least one of the first radio wave receiving unit and the second radio wave receiving unit is received. Although it may be possible to receive both waves, both transmitted waves are provided at positions where a difference (phase difference) depending on the difference in transmittance of each transmitted object occurs. In this way, the structure of the measuring device is simplified by using the phase difference of the radio waves.
In the system, the transmitting side and the receiving side can be separated by making a system that measures the difference between the received radio waves of the two antennas. Since the transmitting side and the receiving side can be separated in this way, the degree of freedom in arranging the device including the radio wave receiving unit is increased.
By comparing the measurement results from the two antennas, it is possible to eliminate the same changes that occur in both antennas.
As a result, changes in the positional relationship between the body and the sensor are eliminated, and a system that is more resistant to noise can be constructed. The receiving unit and the subsequent signal processing unit may be connected wirelessly or the like.

The water content detection unit may obtain the time change of the water content based on the time change of the phase difference.
By measuring the time change of the phase difference, it is possible to measure the time change of biological information such as heart rate variability and respiratory variability in addition to obtaining the body water content.

The water content detection unit may estimate the water content by integrating the phase difference detected by the phase difference detection unit.

The water content detection unit may estimate the water content by measuring the phase difference detected by the phase difference detection unit at different frequencies and taking the product of the water content candidates obtained at different frequencies. good.

Further, a signal strength detection unit for detecting the electric field strength of the received radio wave is provided, and the water content detection unit is the measurement target based on the detection result of the phase difference detection unit and the detection result of the signal strength detection unit. The water content may be estimated.

The water content based on the phase difference can be detected with high resolution, but the water content detection range can measure only a change of one wavelength at the maximum.
Therefore, it is possible to measure the water content with high resolution by measuring the signal strength, which has a wide detection range depending on the water content but has a large signal variation and low resolution, and integrates the phase difference and the two. In addition, the time change of the water content can be obtained in a wide range on the time axis.

Further, in the above, a first bandpass filter is provided between the first radio wave receiving unit and the phase difference detecting unit, and the first bandpass filter is provided between the second radio wave receiving unit and the phase difference detecting unit. By providing a second bandpass filter having the same filter characteristics as the first bandpass filter and setting the filtering frequencies of the first bandpass filter and the second bandpass filter according to the transmission frequency, the above It is advisable to remove other than the radio waves from the radio wave transmitter.

Further, it has a biological information detection unit that detects a signal of biological information based on the phase difference detected by the phase difference detection unit, and the output of the biological information detection unit is used as a detection target item for biological information. It is preferable to provide a third bandpass filter that separates frequencies accordingly.
The frequency suitable for the detection item (breathing detection, pulse detection, etc.) can be detected by the third bandpass filter.

The present invention is a biometric information measuring device using the radio wave type moisture meter according to any one of the above.
Since changes in water content in a living body are often caused by changes in blood volume, urine volume, body fluid volume, etc., it is possible to obtain biological information and its temporal changes by accurately measuring the water content in the living body. Since it can be used, it can be expected to be used in the medical field.
It is preferable that either one of the first radio wave receiving unit and the second radio wave receiving unit is arranged at a position where the transmitted wave penetrates the subject's organ (measurement target organ).

Further, the present invention includes a radio wave transmitting unit for transmitting radio waves and a plurality of radio wave receiving units for receiving a transmitted wave transmitted from the radio wave transmitting unit through a measurement target by at least one radio wave receiving unit. The amount of water to be measured based on the phase difference detection unit that is arranged at different positions and detects the phase difference of the radio waves received by the plurality of radio wave receiving units and the phase difference detected by the phase difference detection unit. This is a radio wave type moisture meter having a moisture amount detecting unit for detecting the above position for each position.
In order to grasp the biological information depending on the position of the living body, the radio wave receiving units may be arranged in an array.
By arranging more sensors (receivers), it is possible to measure the water content at a plurality of locations at the same time. For example, biological information such as water content can be obtained like a two-dimensional image.

Further, the present invention includes a first radio wave receiving unit and the first radio wave receiving unit that receive at least one of the transmitted waves transmitted from the radio wave transmitting unit that transmits radio waves and transmitted from the measurement target. The measurement target is based on a phase difference detection unit that detects the phase difference of radio waves by radio waves received by each of the second radio wave receiving units provided at different positions and a phase difference detected by the phase difference detection unit. It is a signal processing circuit of a radio wave type moisture meter having a moisture content detection unit for detecting the moisture content of.
The present invention is a first radio wave receiving unit and a second radio wave that receive at least one of a radio wave transmitting unit that transmits radio waves and a transmitted wave that the radio waves transmitted from the radio wave transmitting unit have passed through a measurement target. The phase difference detection unit that detects the phase difference of the radio waves received by the receiving unit, the first radio wave receiving unit and the second radio wave receiving unit, and the phase difference detected by the phase difference detecting unit. Based on this, it is a biometric information detection device having a biometric information detection unit that detects the biometric information of the measurement target.

According to another aspect of the present invention, the transmitted wave transmitted from the radio wave transmitting unit that transmits the radio wave passes through the measurement target, and the transmitted wave is transmitted to at least one of the first radio wave receiving unit and the second radio wave receiving unit. On the other hand, it is detected in the step of receiving, the phase difference detection step of detecting the phase difference of the radio waves received by each of the first radio wave receiving unit and the second radio wave receiving unit, and the phase difference detecting step. Provided is a radio wave type moisture measurement method including a moisture content detection step for detecting the moisture content of the measurement target based on the phase difference.
The present invention is a program for causing a computer to execute the radio wave type moisture measurement method described above.

According to the present invention, it is possible to provide a radio wave type moisture meter and a biological information measuring device that are not easily affected by the surroundings.

It is a principle figure of the radio wave moisture meter by embodiment of this invention. It is a functional block diagram which shows one configuration example of the biological information measuring apparatus using the radio wave moisture meter according to 1st Embodiment of this invention. It is a flowchart which shows an example of the flow of the biological information detection processing by this embodiment. It is a modification of FIG. 2A, and is a flowchart showing an example of the flow of the biological information detection process for obtaining biological information in consideration of both the phase difference and the signal strength. It is a figure which shows an example of the waveform of the radio wave obtained along the flow of the biological information detection processing. It is a figure which shows an example of the waveform of the radio wave obtained along the flow of the biological information detection processing. It is the figure which measured the relationship between the phase difference and the water content (water level). It is a figure which shows the relationship between the measurement result and the theoretical value of the figure which shows the relationship between the water level and the delay time of FIG. 4A. It is a figure which shows the example which estimated the water content at the 1st frequency of a plurality of frequencies. It is a figure which shows the example which estimated the water content in the 2nd frequency of a plurality of frequencies. It is a figure which shows the relationship between the water level and the received signal strength. It is the figure which combined the value of the phase difference along the tendency of the relationship between a water level and a received signal. It is a figure which shows the relationship between the phase difference which becomes the base of drawing of FIG. 7A, and the water level (the figure corresponding to the figure 4A above). It is a figure which shows the example of performing the heart rate measurement by the biological information measuring apparatus using the radio wave moisture meter by the 2nd Embodiment of this invention. FIG. 8A is a diagram showing a state in which the subject is sitting on a chair. FIG. 8B is a diagram showing a state in which the subject is away from the chair. FIG. 8A is a diagram showing the positional relationship between the radio wave transmitting unit, the first radio wave receiving unit, the second radio wave receiving unit, and the heart of the subject. It is a figure which shows the more detailed configuration example of FIG. It is a figure which shows an example of the heartbeat, respiration measurement using the biological information measuring apparatus by the 3rd Embodiment of this invention, and also, in order to confirm the accuracy of the heartbeat, respiration measurement technique by this embodiment, in order to confirm. It is a figure which also refers to the simultaneous measurement result by a pulse transducer. It is a figure which shows the state of the simultaneous measurement by a pulse transducer. It is a figure which shows an example of the measurement result which made the abdomen at the time of urination a measurement target by the 3rd Embodiment of this invention. It is a figure which shows an example of the measurement result which made the leg (calf) at the time of cuff release by the 4th Embodiment of this invention (it does not return when pressure is applied to a thigh) as a measurement target. It is a figure which shows an example of the biological information measuring apparatus by 5th Embodiment of this invention, and is the figure which shows the state of measuring the water content of a leg part at the time of head-up / head-down. It is a figure which shows the measurement result of the water content of a leg at the time of head up / head down, and changes with time by corresponding the waveform based on a phase difference, the waveform based on the received signal strength, and the change of the foot thickness by a strain gauge. It is a figure shown. It is a figure which shows an example of the biological information measuring apparatus by the 6th Embodiment of this invention. It is a figure which shows the transportation means such as the automobile provided with the biological information measuring apparatus according to 7th Embodiment of this invention.

In the present specification, the term "radio wave" refers to an electromagnetic wave having a lower frequency (longer wavelength) than light, and more specifically, an electromagnetic wave having a frequency of 3 THz or less, particularly an extremely low frequency of 50 Hz. It refers to electromagnetic waves from long waves to submillimeter waves of about 3 THz. Microwave refers to an electromagnetic wave having a frequency of about 300 MHz to 300 GHz.
Further, in the present specification, in the frequency range of electromagnetic waves, electromagnetic waves (radio waves) in the frequency band from 50 Hz to 3 THz are used because they hardly transmit the living body at 3 THz or higher and directivity cannot be obtained at 50 Hz or lower. It is preferable to use it, and more preferably, an electromagnetic wave (microwave) in the range of 300 MHz to 300 GHz is used.
In the following, an example in which microwaves are used as radio waves will be described, but radio waves in other frequency bands can be used, and the purpose is not limited to microwaves.
It is considered that the influence of noise in the measurement technology of biological information is derived from the fact that the part to be measured is the body surface. When a contact-type sensor is used, it is difficult to measure biological information in a vibrating car because it is greatly affected by the movement of the body. In addition, although the technology using microwave reflection, electrolytic resonance, and capacitive coupling is non-contact measurement, the measurement result changes greatly due to the change in the distance between the sensor and the body. Therefore, in the measurement in a vibrating environment, there arises a problem that a large noise is added.
Currently, the biometric information measurement technology using a non-contact sensor that is being developed has the drawback of being vulnerable to noise caused by vibration, and the only items that can be measured are heart rate and respiratory rate.
The biological information measurement technique according to the present embodiment described below can not only stably measure heartbeat and respiration, but also determine body water content, body water distribution, cardiac output, bladder urine volume, cerebral blood flow, etc. It makes it possible to measure changes in water content in the body.

First, the features of the biometric information measurement technique using the non-contact sensor according to the present embodiment will be described.
1) Points where the transmission of microwaves is used to measure biological information Systems using microwave reflections are known, but most of the reflected waves are reflected on the body surface, so the body fluctuates with respiration and heartbeat. It measures the surface.
On the other hand, by using the transmitted microwave, it is possible to measure the state inside the body instead of the surface of the body, so that more information including the information inside the body can be measured.

2) A system that measures the transmission of microwaves with two antennas and measures the phase difference Although it is different from the measurement technology of biological information, there is a measurement system that uses the transmission of microwaves. In the biometric information measurement system using the transmission of these microwaves, a method of measuring the transmission time and the phase difference between the transmitted microwave and the received microwave is used.
On the other hand, in the biometric information measurement technique according to the present embodiment, it is possible to separate the transmitting side and the receiving side by measuring the phase difference of the microwaves received by at least two antennas.
By separating the transmitting side and the receiving side, the arrangement of the biometric information measuring device can be made more free.

By comparing the microwave measurement results of the two receiving antennas, it is possible to eliminate the same changes that occur in both antennas. As a result, changes due to the positional relationship between the measurement target (body) and the sensor can be removed, and the system can be made more resistant to noise.
In addition, by measuring the time change of the phase difference, the time change of the body water content can be accurately measured, and in addition, the time change of important measurement items in the living body such as heart rate variability and respiratory variability can be accurately measured. can do.

3) A system that measures the signal strength (decrease) in addition to the microwave phase difference The phase difference can be measured with high resolution, but only one wavelength change can be measured at the maximum. Therefore, by simultaneously measuring the signal strength having a wide measurement range of change but having a large variation and low resolution and integrating it with the measurement result of the phase difference, it is possible to measure the biological information in a wide range with high resolution.

Hereinafter, embodiments of the present invention will be described in detail. FIG. 1A is a principle diagram of a radio wave moisture meter according to the present embodiment. In this embodiment, attention is paid to the property that the propagation speed of radio waves is reduced by moisture. As shown in FIG. 1A, radio waves are transmitted when they propagate and receive only in the air (upper figure: t0-t1) and when they propagate (transmit) through water (lower figure: t0-t1). There is a difference in the time required from reception to reception (t1 in the upper figure and t1 in the lower figure). In this way, the phase difference can be obtained by comparing the phases of the received signals between the different receiving units, and the water content can be measured from the phase difference, that is, the delayed time.

(First Embodiment)
FIG. 1B is a functional block diagram showing a configuration example of a biological information measuring device using a radio wave moisture meter according to an embodiment of the present invention.
As shown in FIG. 1B, in the radio wave moisture meter A according to the present embodiment, the radio wave transmitting unit (transmitting unit) 1 that transmits microwaves and the microwave transmitted from the radio wave transmitting unit 1 are measurement targets H such as humans. It has a first radio wave receiving unit 3 and a second radio wave receiving unit 5 for receiving the transmitted waves transmitted through the above. For example, the first radio wave receiving unit 3 is arranged at a position where it receives radio waves that do not pass through the human organ H1, and the second radio wave receiving unit 5 is arranged at a position where it receives radio waves that pass through the human body organ H1. There is. Utilizing the fact that the magnetic permeability of microwaves differs between the organ H1 and the portion without an organ.

The transmitted wave is provided at a position where at least one of the first radio wave receiving unit 3 and the second radio wave receiving unit 5 is received. It may be possible to receive both, but both transmitted waves are provided at different positions so that a difference (phase difference) occurs. The first radio wave receiving unit 3 and the second radio wave receiving unit 5 may each have an antenna unit, electrodes, or the like.
Further, among the outputs of the first radio wave receiving unit 3 and the second radio wave receiving unit 5, the first bandpass filter 7 and the first bandpass filter 7 for removing microwaves other than the wavelength region of the microwave transmitted from the radio wave transmitting unit 1 It has a second bandpass filter 11. The first bandpass filter 7 and the second bandpass filter 11 may have the same filtering characteristics.

It has a phase difference detecting unit 15 for detecting a phase difference and a signal strength detecting unit 17 for detecting a signal strength based on the outputs from each of the first bandpass filter 7 and the second bandpass filter 11. ..
Further, the A / D conversion unit 21 that A / D-converts the phase difference signal detected by the phase difference detection unit 15 and the signal strength detected by the signal strength detection unit 17, and the output from the A / D conversion unit 21. It has a biometric information detection unit 23 that detects biometric information based on the above. Biological information includes the amount of water. In addition, it is possible to detect various kinds of biological information related to the amount of water, which will be described later.

FIG. 2A is a flowchart showing an example of the flow of the biological information detection process according to the present embodiment. FIG. 2B is a modification of FIG. 2A, and is a flowchart showing an example of a flow of biometric information detection processing for obtaining biometric information in consideration of both a phase difference and a signal strength.
3A and 3B are diagrams showing an example of a microwave waveform obtained along the processing flow. The horizontal axis is time and the vertical axis is signal strength.
As shown in FIG. 2A, the biological information acquisition process is started (Start), and in step S1, microwaves are transmitted from the radio wave transmission unit 1. 1) Sg1 in FIG. 3A is an example of the transmitted microwave waveform, and for example, a sine wave is transmitted. In step S2, the first radio wave receiving unit 3 and the second radio wave receiving unit 5 receive microwaves individually. 2) Sg2 in FIG. 3A and 3) Sg3 in FIG. 3A show an example of the obtained microwave. As shown in the figure, there is noise.

Next, in step S3, the pandapass filter process is performed by the first bandpass filter 7 and the second bandpass filter 11. Then, as shown in 4) Sg4 of FIG. 3B and Sg5 of 5) of FIG. 3B, noise is removed and a clean waveform is obtained.
In step S4, the phase difference detection unit 15 obtains the phase difference between 4) Sg4 in FIG. 3B and Sg5 in 5) in FIG. 3B. Then, as shown in FIG. 3B, the phase difference signal Sg6 is obtained. The phase difference is a signal for one wavelength. This phase difference is obtained based on the transmission of the transmitted wave, and is based on, for example, the difference in the amount of water based on the position of the living body. Therefore, according to the present embodiment, a difference in water content can be obtained (see also FIG. 1A).
Next, in step S5, the phase difference can be A / D converted by the A / D conversion unit 21, and the biological information can be detected by the biological information detection unit 23 in step S6. As a result, the process ends (End).
When detecting biological information based on the phase difference, for example, a method of obtaining a calibration curve based on past detection results and converting the phase difference into biological information based on the calibration curve is used. Can be done.

Alternatively, as shown in the flowchart shown in FIG. 2B, the signal strength is detected by the signal strength detection unit 17 (5 in FIG. 3B) Sg5, 7) Sg7) in step S11 from step S4 in FIG. 2A, and in step S12. , Biometric information may be detected based on the phase difference and the signal strength. Other exemplary methods will also be described below.

FIG. 4A is a diagram in which the relationship between the phase difference and the water content (water level) is actually measured. As shown in FIG. 4A, since the phase difference is for one wavelength, the phase difference shows an accurate value with respect to the water level, but is shown as a periodic value. Therefore, only the relative change can be obtained for a certain water level range from the phase difference alone. Therefore, for example, the following method for estimating the amount of water can be used.

As the first method for estimating the water content, the water content can be obtained by the phase difference integration process (see the lower figure of FIG. 4A). FIG. 4B is a diagram showing the relationship between the measurement result and the theoretical value of the diagram showing the relationship between the water level and the delay time in FIG. 4A. As shown in FIG. 4B, it can be seen that a value similar to the theoretical value can be obtained up to a certain water level by the phase difference integration process. In this way, it can be seen that the water content close to the theoretical value can be obtained by obtaining the phase difference and integrating it.

As a second method for estimating the water content, the water content can be obtained by synthesizing a plurality of frequencies instead of integrating the phase differences. That is, by obtaining the phase difference at different frequencies, a plurality of water amounts can be estimated from one frequency, but by multiplying the candidates for the water content obtained from a plurality of frequencies, both frequencies can be estimated. Candidates can be selected.

5A and 5B are diagrams showing an example of the principle of estimating the amount of water by a plurality of frequencies. For example, if the water level is 18 mm when measured at the first frequency (first wavelength) shown in FIG. 5A, an intersection appears at the first wavelength with a phase difference of about 75 degrees (see arrow). When calculated from the phase difference of 75 degrees measured at the intersection, a plurality of candidates (here, five candidates) can be obtained as the water content (water level) of 18 mm, 38 mm, 58 mm, 78 mm, and 98 mm.
On the other hand, as shown in FIG. 5B, when measured at a second frequency (second wavelength) different from the first frequency, an intersection appears when the phase difference is about 0 degrees (see the arrow). When calculated from the phase difference of 0 degrees measured at the intersection, candidates (here, three candidates) of 18 mm, 51 mm, and 84 mm can be obtained as the water content (water level).
When the candidates obtained from these two wavelengths are combined (when the product (AND) of the two is taken), the water content (water level) can be estimated to be 18 mm.

As a third method for estimating the water content, the water content can also be obtained by synthesis based on the electric field strength and the phase difference.
FIG. 6 is a diagram showing the relationship between the water level and the received signal strength. As shown in FIG. 6, the received signal strength can be obtained to be close to the theoretical value over a wide range of the water level. However, the accuracy of the value itself should be obtained from the phase difference.

Therefore, as shown in FIGS. 7A and 7B, biometric information that is more accurate than the measurement based on the reception intensity alone is detected by synthesizing the phase difference values along the tendency of the relationship between the water level and the reception intensity. be able to.
FIG. 7A is a diagram in which the values of the phase difference are combined along with the tendency of the relationship between the water level and the received signal. FIG. 7B is a diagram showing the relationship between the phase difference and the water level, which is the basis of the drawing of FIG. 7A (the diagram corresponding to FIG. 4A).

Explaining the processing contents in more detail, in step 1, a rough water level is selected from the received signal strength (A1, B1, C1).
In step 2, the water level is selected in the range of A1, B1 and C1 from the phase difference.
For example, if the received signal strength is -40dbm, B1, when the phase difference is 50 degrees, multiple water levels are estimated as 18mm, 32mm, 48mm, but A1, B1, C1 can be selected from the received signal strength. Therefore, if it is −40 dBm, the water level can be estimated to be 32 mm of B1.
In this way, the phase difference signal can measure the water content in detail, but it is shaken off by a large change. Therefore, by measuring a rough change from the reception intensity and finely measuring the range by the phase difference, it is possible to detect a wide range with high accuracy.
As described above, according to the present embodiment, the water content can be accurately determined. Therefore, accurate measurement of biological information depending on the amount of water is possible.
For example, it may be possible to detect even a slight lesion of an organ.

An example of the positional relationship between the radio wave transmitting unit and the radio wave receiving unit will be described.
1) Basic example: A configuration having one radio wave transmitting unit and two or more radio wave receiving units.
2) Application example 1: An example in which the signal of the radio wave transmitting unit is divided into two and the first transmitting signal and the received signal received by the radio wave receiving unit are compared.
3) Application example 2: A configuration example having one radio wave transmitting unit, one radio wave receiving unit, and a signal generating unit that generates a signal having the same frequency as the radio wave transmitting unit, a signal between the radio wave transmitting unit and the signal generating unit. By comparing, the amount of water can be detected.
4) It has a plurality of radio wave transmitting units for transmitting microwaves having different frequencies, a radio wave receiving unit, and a signal generating unit. In the signal generation unit, the signal generation unit generates a signal combined with signals of different frequencies transmitted from the radio wave transmission unit to obtain a phase difference based on the transmission of a plurality of paths and detect the water content. In this case, an electromagnetic wave in a wavelength range of a radio wave having a band wider than that of a microwave (for example, 50 Hz to 3 THz band) may be used.
In addition, it is possible to compare a plurality of routes by switching the transmission timing with a plurality of radio wave transmission units.

(Second Embodiment)
Next, the biological information measuring device according to the second embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 8 is a diagram showing an example of performing heart rate measurement. FIG. 8A is a diagram showing a state in which the subject H is sitting on the chair 22. The radio wave transmitting unit 1 is arranged in front of the subject, and the first radio wave receiving unit 3 and the second radio wave receiving unit 5 are arranged at different positions on the back surface of the subject H. FIG. 8B is a diagram showing a state in which the subject H is separated from the chair 22. FIG. 9 is a diagram showing the positional relationship between the radio wave transmitting unit 1, the first radio wave receiving unit 3, the second radio wave receiving unit 5, and the heart 31 of the subject H in FIG. 8A. FIG. 10 is a diagram showing a more detailed configuration example of FIG.
For example, a heart rate measurement experiment can be performed while sitting and wearing clothes. It can be measured at rest (when breathing normally).

As shown in FIG. 9, the body of the subject H is arranged between the radio wave transmitting unit 1, the first radio wave receiving unit 3, and the second radio wave receiving unit 5. In particular, the heart 31 is not arranged between the radio wave transmitting unit 1 and the first radio wave receiving unit 3, and the heart 31 is located between the radio wave transmitting unit 1 and the second radio wave receiving unit 5. Have been placed. As shown in FIG. 10, the radio wave transmitting unit 1 has an output of 4 dBm at a frequency of about several GHz, for example, 2300 to 2500 MHz. The distance between the radio wave transmitting unit 1, the first radio wave receiving unit 3, and the second radio wave receiving unit 5 is 400 mm.
Biological information can be obtained by the biological information detection circuit 23 from the phase difference between the received signals of the first radio wave receiving unit 3 and the second radio wave receiving unit 5.
FIG. 11A is a diagram showing an example of heart rate and respiration measurement, and also refers to the result of simultaneous measurement by a pulse transducer in order to confirm the accuracy of the heart rate and respiration measurement technique according to the present embodiment. FIG. 11B is a diagram showing a state of simultaneous measurement by the pulse transducer.

In the present embodiment, the body water content to be measured is the cardiac output and the urine volume. Cardiac output is the amount of blood that is expelled from the heart in one minute. Currently, the bioelectrical impedance method has been put into practical use as a method for measuring cardiac output.
However, the bioelectrical impedance method has a problem that it involves contact because it is necessary to attach an electrode to the body.
Regarding the amount of urine, a measurement method using an ultrasonic sensor has been put into practical use.
However, in the measurement method using the ultrasonic sensor, it is necessary to make contact with the skin via a gel peculiar to ultrasonic measurement, and this also involves contact.
In the measurement method involving contact as described above, the person to be measured is uncomfortable and the measurement environment is restricted.
In order to solve these problems, a technique for measuring cardiac output and urine volume will be described in the present embodiment by using a non-contact measurement technique for body water content.

The waveform shown in FIG. 11A (a) is raw data (waveform) detected by the biological information detection unit 23 of the radio wave moisture meter A shown in FIG. 1B. This raw data is a diagram showing the time change of the delay time (arbitrary unit) of the microwave based on the obtained water content based on the method and the like shown in FIG. 5 for integrating the phase difference.
By measuring the time change of the phase difference, it becomes possible to measure not only the amount of body water but also the time change such as heart rate variability and respiratory variability.
FIG. 11A (b) is a diagram showing an example of a waveform obtained by passing the raw data shown in FIG. 11A (a) through a heartbeat extraction bandpass filter (0.4 to 10 Hz) suitable for heartbeat extraction.
FIG. 11A (c) is a diagram showing an example of a waveform obtained by passing the raw data shown in FIG. 11A (a) through a respiratory extraction bandpass filter (0.2 to 0.4 Hz) suitable for respiratory extraction. ..
As shown in FIG. 11A (d), it can be seen that the heartbeat waveform obtained based on the non-contact measurement technique for body water content according to the present embodiment shows good agreement with the waveform of the pulse transducer for comparison. ..

Further, as shown in FIG. 11A (c), it is within the range of 12 to 18 times, which is about 15 times per minute, and it can be seen that extraction can be performed with good accuracy.
By taking out the phase difference between the first radio wave receiving unit 3 and the second radio wave receiving unit 5 in this way, it is possible to investigate the change in the amount of water caused by the heart, that is, the change in the cardiac output. ..
It is also possible to extract the respiratory waveform.
Further, by using a bandpass filter, it is possible to narrow down the measurement target of biological information.
As described above, according to the present embodiment, the discomfort of the person to be measured and the binding of the measurement environment, which have been problems when the conventional contact-type biometric information detection technology is used, are suppressed, and the body moisture is suppressed. It can be seen that it is possible to measure biological information in a non-contact manner based on the non-contact measurement technology for quantity.

(Third Embodiment)
Next, the biological information measuring device according to the third embodiment of the present invention will be described in detail with reference to the drawings.
The target of the biological information detection technique according to this embodiment is the amount of urine. FIG. 12 is a diagram showing an example of measurement results in which the abdomen during urination according to the present embodiment is measured. In FIG. 12, the signal Sg6 is a diagram showing the time change of the (delay time) of the water content obtained based on the integration of the phase difference.

Further, in FIG. 12, the signal Sg7 is a diagram showing the time change of the (delay time) of the water content obtained based on the received signal strength.
As shown in FIG. 12, in the present embodiment, it can be seen that the signal Sg7 based on the reception intensity and the signal Sg6 based on the phase difference have the same general tendency of time change. However, since the signal Sg6 based on the phase difference also represents a fine change, more accurate biological information can be obtained.
In this way, by setting the measurement site to the abdomen, it is possible to measure the water accumulated in the bladder and use it to promote urination.

(Fourth Embodiment)
Next, the biological information measuring device according to the fourth embodiment of the present invention will be described in detail with reference to the drawings.
The target of the biological information detection technique according to this embodiment is the water content of the calf.
FIG. 13 is a diagram showing an example of measurement results for the legs (calves) at the time of cuff release according to the present embodiment (when pressure is applied to the thighs, the legs do not return). In FIG. 13, the signal Sg6 is a diagram showing the time change of the (delay time) of the water content obtained based on the integration of the phase difference.
Further, in FIG. 13, the signal Sg7 is a diagram showing the time change of the (delay time) of the water content obtained based on the received signal strength.

Further, in FIG. 13, the signal Sg11 is a diagram showing a change in the thickness of the foot (depending on the strain gauge).
Time t = 5 minutes indicates the period of ischemia by the thigh cuff.
As shown in FIG. 13, the change in the foot thickness by the strain gauge is in good agreement with the detection result of the water content based on the phase difference rather than the change based on the received signal strength. From this, it can be seen that the change in calf water content can be accurately measured by the water content detection technique based on the phase difference according to the present embodiment. Using this technology, it is also possible to monitor economy syndrome and the like.

(Fifth Embodiment)
Next, the biological information measuring device according to the fifth embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 14 is a diagram showing an example of the biological information measuring device according to the present embodiment, and is a diagram showing how the water content of the leg portion at the time of head-up / head-down is measured. Reference numeral 53 is a horizontal line (reference line). The left figure of FIG. 14 is a view showing a state in which the subject H is lying on the horizontal bed 51, and the water content is measured on the legs of the subject according to the first to fourth embodiments of the present invention. It is a figure which shows the example in which the apparatus 55 is arranged. The upper right view of FIG. 14 shows the head-up state, and the lower right figure of FIG. 14 shows the head-down state.

FIG. 15 is a diagram showing the measurement results of the water content of the legs during head-up / head-down. Waveform Sg7 based on the phase difference, waveform Sg7 based on the received signal strength, and change in foot thickness Sg11 by the strain gauge. It is a figure which showed the time change corresponding to.
On the time axis (horizontal axis), the signal changes by changing the motion 1) head up 15 degrees, 5 minutes, motion 2) head up 30 degrees, 5 minutes, motion 3) head down 5 degrees, 5 minutes. I checked.

Then, it can be seen that the higher the head-up angle, the larger the change in both Sg6 and Sg7, and that the change in the water content is detected even in the head-down.
As described above, according to the present embodiment, it can be seen that the change (body fluid shift) due to gravity of the body fluid (blood) can be measured.
From this, it can be seen that by using the biological information detection technique according to the present embodiment, it can be utilized for venous condition monitoring. By using the leg as the measurement site, it is possible to measure the accumulation of venous blood in the leg and use it as a countermeasure for economy syndrome.

(Sixth Embodiment)
Next, the biological information measuring device according to the sixth embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 16 is a diagram showing an example of the biological information measuring device according to the present embodiment, in which the subject H is lying horizontally on the bed 81, the radio wave transmitting unit 1 is arranged above the bed 81, and the subject H is under the bed 81. , 1st and 2nd radio wave receiving units 3 and 5 are arranged. By arranging the first radio wave receiving unit 3 under the organ 31 such as the heart in the body of the subject and the second radio wave receiving unit 5 at a position where there is no organ, changes in the blood flow of the heart and the like are measured. be able to.
Further, the organ to be measured may be switched by moving the bed 81 in the horizontal direction.
By arranging the first or second radio wave receiving units, which are the sensors on the receiving side, in an array, it is possible to make a system in which more sensors are arranged and measurements are performed at a plurality of locations at the same time.

(7th Embodiment)
Next, the biological information measuring device according to the seventh embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 17 is a diagram showing a means of transportation such as an automobile 71 equipped with a biological information measuring device according to the present embodiment. In the driver's seat of the automobile 71, the radio wave transmitting unit 1 is arranged at the upper part, and for example, the first and second radio wave receiving units 3 and 5 are arranged at different positions on the back surface of the seat. The first radio wave receiving unit 3 is placed in the body of the subject at a position where microwaves pass through the organ 31 such as the heart, and the second radio wave receiving unit 5 is placed at a position where microwaves do not pass through the organ 31 such as the heart. Place it.

For example, when an abnormal increase or decrease in heart rate is detected, the speed may be automatically reduced or the vehicle may be stopped.
As described above, the biological information detection technique according to the present embodiment can be used as a sensor for automatic driving. At that time, unlike the contact type sensor, even if the driver changes, the sensor portion can be used as it is without changing.

As an application example of the radio wave type moisture meter according to the present invention, a technology for monitoring the biological information of a driver during automatic driving, a medical examination at a hospital or an examination related to a disease, a state of a subject in a bed including a hospital, a nursing facility, or a home. It can be applied to the monitoring technology of the subject and the monitoring technology of the subject's condition by installing it in a wheelchair or a seat.
In addition, by changing the measurement site to the abdomen, chest, head, legs, etc., it is possible to monitor information such as organs existing in each part in a non-contact manner.
The present invention can also be used for detecting pulmonary edema, pulmonary hemorrhage, hydrocephalus, pleural effusion, ascites, and the like.
In addition, the moisture meter according to the present embodiment can be applied to a field different from the biological information detection. For example, it can be used for monitoring soil moisture content in agricultural land. That is, the moisture can be easily measured and the contacts do not rust because they are non-contact. Therefore, it is also suitable for long-term monitoring of soil moisture content on agricultural land.
In addition, by measuring the water content of the crop, it can be applied to the monitoring of the water condition of the crop itself.

(Summary)
With the conventional biological information measurement method using microwave reflection, it is difficult to limit the measurement location, and there is a problem that the movement of various objects around the measurement is also measured. In addition, there is a problem that it is vulnerable to noise such as vibration.
On the other hand, according to the water content measurement technique of the present invention, the permeation path can be limited, so that the measurement site can be easily limited.
By increasing the number of receiving antennas to two or more for one microwave transmitter, it is possible to measure at a plurality of parts. Since it is easy to measure with a plurality of sensors, it is possible to easily detect a sensor failure.

Since the present invention is a system that utilizes the transmission of microwaves, it is possible to measure changes in the amount of water in each measurement target site in a non-contact manner. For example, changes in water content in a living body are caused by items such as changes in blood volume, urine volume, and body fluid volume. According to the present invention, non-contact measurement for these items is possible.
The microwave used in the present invention is, for example, a 1 to 2 GHz band, which is a radio wave band that is currently in widespread use, so that both the transmitter and the receiver can be obtained at a very low cost. Further, since the phase difference detector can also be measured by incorporating one IC, it can be realized as a very small and inexpensive system.

In the future, when disease prediction / prevention utilizing artificial intelligence (AI) is realized, biological information measurement in daily life will be required more. At this time, since more information can be measured, the accuracy of disease prediction is greatly improved. Therefore, more kinds of information can be measured for measuring biological information in daily life.
The present invention has an advantage that measurement is possible if there are two or more measurement targets having different magnetic permeability.

Processing and control can be performed by software processing by CPU (Central Processing Unit) or GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Hardware).
Further, in the above-described embodiment, the configurations and the like shown in the drawings are not limited to these, and can be appropriately changed within the range in which the effects of the present invention are exhibited. In addition, it can be appropriately modified and implemented as long as it does not deviate from the scope of the object of the present invention.

In addition, each component of the present invention can be arbitrarily selected, and an invention having the selected configuration is also included in the present invention.
Further, the program for realizing the function described in the present embodiment is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into the computer system and executed to process each part. May be done. The term "computer system" as used herein includes hardware such as an OS and peripheral devices.

In addition, the "computer system" includes a homepage providing environment (or display environment) if a WWW system is used.
Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storage device such as a hard disk built in a computer system. Further, a "computer-readable recording medium" is a communication line for transmitting a program via a network such as the Internet or a communication line such as a telephone line, and dynamically holds the program for a short period of time. In that case, it also includes the one that holds the program for a certain period of time, such as the volatile memory inside the computer system that becomes the server or client. Further, the program may be for realizing a part of the above-mentioned functions, and may be further realized by combining the above-mentioned functions with a program already recorded in the computer system. At least some of the functions may be realized by hardware such as integrated circuits.

The present invention can be used for a biological information detection device.

A Radio Moisture Analyzer H Measurement target (subject)
H1 Organ 1 Radio wave transmission unit 3 First radio wave reception unit 5 Second radio wave reception unit 7 First bandpass filter 11 Second bandpass filter 15 Phase difference detection unit 17 Signal strength detection unit 21 A / D conversion unit 23 Biometric information detector

Claims (14)

A radio wave transmitter that transmits radio waves and
A first radio wave receiving unit and a second radio wave receiving unit, in which the radio wave transmitted from the radio wave transmitting unit receives at least one of the transmitted waves transmitted through the measurement target,
A phase difference detection unit that detects the phase difference of the radio waves received by each of the first radio wave receiving unit and the second radio wave receiving unit, and
A radio wave type moisture meter having a moisture content detection unit that detects the moisture content of the measurement target based on the phase difference detected by the phase difference detection unit. The water content detection unit
The radio wave type moisture meter according to claim 1, wherein the time change of the water content is obtained based on the time change of the phase difference. The water content detection unit
The radio wave type moisture meter according to claim 1 or 2, wherein the moisture content is estimated by integrating the phase difference detected by the phase difference detecting unit. The water content detection unit
The radio wave type moisture according to claim 1 or 2, wherein the phase difference detected by the phase difference detection unit is measured at different frequencies, and the moisture content is estimated by taking the product of the candidates for the moisture content obtained at different frequencies. Total. Furthermore, it is equipped with a signal strength detector that detects the signal strength of the received radio wave.
The water content detection unit
The radio wave type moisture meter according to claim 1 or 2, which estimates the water content of the measurement target based on the detection result of the phase difference detection unit and the detection result of the signal strength detection unit. A first bandpass filter is provided between the first radio wave receiving unit and the phase difference detecting unit.
A second bandpass filter having the same filter characteristics as the first bandpass filter is provided between the second radio wave receiving unit and the phase difference detecting unit.
Any one of claims 1 to 5 that removes radio waves other than radio waves from the radio wave transmitting unit by setting the filtering frequencies of the first bandpass filter and the second bandpass filter according to the transmission frequency. The radio wave type moisture meter described in the section. Further, it has a biometric information detection unit that detects a biometric information signal based on the phase difference detected by the phase difference detection unit.
The radio wave type moisture meter according to any one of claims 1 to 6, further comprising a third bandpass filter that frequency-separates the output of the biological information detection unit according to the biological information to be detected. .. A biometric information measuring device using the radio wave type moisture meter according to any one of claims 1 to 7. The biometric information measuring device according to claim 8, wherein either one of the first radio wave receiving unit and the second radio wave receiving unit is arranged at a position where the transmitted wave passes through the organ. A radio wave transmitter that transmits radio waves and
A plurality of radio wave receiving units for receiving the transmitted wave transmitted from the radio wave transmitting unit through the measurement target by at least one of the radio wave receiving units are arranged at different positions.
A phase difference detection unit that detects the phase difference of the radio waves received by the plurality of radio wave reception units, and a phase difference detection unit.
A radio wave type moisture meter having a moisture content detecting unit that detects the moisture content of the measurement target for each position based on the phase difference detected by the phase difference detecting unit. A first radio wave receiving unit and a position different from the first radio wave receiving unit, which receives at least one of the transmitted waves transmitted from the radio wave transmitting unit that transmits radio waves transmitted from the measurement target. A phase difference detection unit that detects the phase difference of radio waves based on the radio waves received by each of the two radio wave reception units,
A signal processing circuit of a radio wave type moisture meter including a moisture content detecting unit that detects the moisture content of the measurement target based on the phase difference detected by the phase difference detecting unit. A radio wave transmitter that transmits radio waves and
A first radio wave receiving unit and a second radio wave receiving unit, in which the radio wave transmitted from the radio wave transmitting unit receives at least one of the transmitted waves transmitted through the measurement target,
A phase difference detection unit that detects the phase difference of the radio waves received by each of the first radio wave receiving unit and the second radio wave receiving unit, and
A biological information detection device including a biological information detection unit that detects biological information of a measurement target based on the phase difference detected by the phase difference detection unit. A step of receiving a transmitted wave in which a radio wave transmitted from a radio wave transmitting unit that transmits radio waves has passed through a measurement target is received by at least one of a first radio wave receiving unit and a second radio wave receiving unit.
A phase difference detection step for detecting the phase difference of the radio waves received by each of the first radio wave receiving unit and the second radio wave receiving unit, and
A radio wave type moisture measurement method including a moisture amount detection step for detecting the moisture amount of the measurement target based on the phase difference detected in the phase difference detection step. A program for causing a computer to execute the radio wave type moisture measurement method according to claim 13.