WO2021090955A1 - Biosignal detection device, heart rate signal detection server, vehicle, biosignal detection program, and heart rate signal detection program - Google Patents

Abstract

The purpose is to acquire a biosignal for a subject seated in a vehicle or the like.　A heart rate signal detection device 11 is provided with a resonance circuit 1a that detects a cardiorespiratory signal based on heart rate and respiration and a resonance circuit 1b that detects a respiratory signal based on respiration. The resonance circuit 1a is provided with a flat capacitor 3a that is mounted at the position of the heart of a subject 10, and the resonance circuit 1b is provided with a flat capacitor 3b that is mounted at the position of the lungs. A signal processing device 16, by subtracting the respiratory signal from the cardiorespiratory signal, removes the respiratory component included in the cardiorespiratory signal and outputs a heart rate signal that is the difference between the two signals. The heart rate signal detection device 11 can be installed in a vehicle to monitor the physical condition of a driver, and, in this case, if the capacitors 3a, 3b are built into a driver's seat or a seatbelt, the capacitors can be mounted without imposing a burden on the driver.

Description

Biological signal detection device, heartbeat signal detection server, vehicle, biological signal detection program, and heartbeat signal detection program

The present invention relates to a biological signal detection device, a heartbeat signal detection server, a vehicle, a biological signal detection program, and a heartbeat signal detection program, for example, a device that measures a biological signal using a capacitance.

For example, while driving a vehicle, the driver's tension may increase, so it is required to monitor whether or not the driver is in good physical condition.
Confirmation of pulse waves is important for grasping the health condition of the driver, and it is extremely effective as a means for detecting signs of illness, especially abnormalities in the circulatory system.
Driving is a daily operation, and a non-contact pulse measurement method is required in order to measure biological signals such as a pulse without imposing a burden on the driver.

As such a pulse wave measurement technique, there is "Measurement system and measurement method" of Patent Document 1.
In this technology, a resonance circuit is constructed by using a capacitor, a coil, or the like, and a sensing element connected in parallel with the capacitor is brought closer to the vicinity of the heart of the human body.
Since the sensing element and the human body portion of the heart region are capacitively coupled, the pulse of the heart can be detected as a change in the resonance frequency.
Since the sensing element can be worn on clothes without contacting the human body, it is suitable for mounting on a vehicle.

Japanese Unexamined Patent Publication No. 2018-186890

However, with the conventional technology, there is a problem that it is difficult to extract biological signals such as heartbeat components from these because the effects of body movement and respiration are detected in addition to the heartbeat.

An object of the present invention is to acquire a biological signal of a subject seated in a vehicle or the like.

(1) In the invention according to claim 1, a seating member on which a subject for biological signal detection is seated and an organ in the seating member that is installed at the heart region of the subject and reaches the heart region of the subject. A first capacitor that is capacitively coupled to the subject, a second capacitor that is installed at the lung site of the subject in the seating member, and is capacitively coupled to an organ that reaches the lung region of the subject, and the above. A first biological signal based on a temporal change in the capacitance of the first capacitor coupled with capacitance, and a second biological signal based on a temporal change in the capacitance of the second capacitor coupled with capacitance. The present invention provides a biological signal detecting device including a biological signal acquiring means for acquiring the above, and a biological signal output means for outputting the acquired first biological signal and a second biological signal.
(2) In the invention according to claim 2, at least one of the first capacitor and the second capacitor is installed on the backrest portion of the seating member, and the other is installed on the seat belt portion. The biological signal detection device according to claim 1, wherein the biological signal detection device is provided.
(3) In the invention according to claim 3, the output first biological signal and the second biological signal are acquired, and the acquired first biological signal is synchronized with the first biological signal. Claim 1 or claim 2 is characterized by comprising a heartbeat signal acquisition means for acquiring a heartbeat signal using the difference between the biological signals of 2 and a heartbeat signal output means for outputting the acquired heartbeat signal. The biological signal detection device according to the above is provided.
(4) The invention according to claim 4, wherein the first biological signal and the second biological signal that have been output are transmitted to a predetermined server device. Alternatively, the biological signal detection device according to claim 2 is provided.
(5) In the invention according to claim 5, the biological signal receiving means for receiving the first biological signal and the second biological signal from the biological signal detecting device according to claim 4, and the first received biological signal. It is provided with a heartbeat signal acquisition means for acquiring a heartbeat signal using a difference between a biological signal and a second biological signal synchronized with the first biological signal, and a heartbeat signal output means for outputting the acquired heartbeat signal. Provided is a heartbeat signal detection server characterized by the above.
(6) In the invention according to claim 6, the biological signal detection device according to any one of claims 1 to 4 is provided, and the seating member is provided in the driver's seat. Provide a vehicle characterized by.
(7) In the invention according to claim 7, the temporal time of the capacity of the first capacitor that electrostatically couples with the organ reaching the heart region of the subject, which is installed in the heart region of the subject for biological signal detection. Based on the temporal change in the capacity of the first biological signal based on the change and the capacity of the second capacitor that is electrostatically coupled to the organ reaching the lung region of the subject, which is installed in the lung region of the subject. Provided are a biological signal acquisition function for acquiring a second biological signal, a biological signal output function for outputting the acquired first biological signal and a second biological signal, and a biological signal detection program realized by a computer. To do.
(8) In the invention according to claim 8, the biological signal receiving function for receiving the first biological signal and the second biological signal from the biological signal detecting device according to claim 4, and the received first biological signal. A computer performs a heartbeat signal acquisition function that acquires a heartbeat signal using a difference between a biological signal and a second biological signal that synchronizes with the first biological signal, and a heartbeat signal output function that outputs the acquired heartbeat signal. To provide a heartbeat signal detection program realized in.

According to the present invention, the biological signals of the organs reaching the heart region of the seated subject and the biological signals of the organs reaching the lung region can be acquired by the first capacitor and the second capacitor.

It is a figure for demonstrating the operation principle of a resonance circuit. It is a figure for demonstrating the structure of the heartbeat signal detection apparatus. It is a figure for demonstrating the hardware configuration of a signal processing apparatus. It is a figure for demonstrating the structure of a capacitor. It is a figure for demonstrating the difference of the measurement area by the size of the electrode area of a capacitor. It is a figure which showed the mounting example of a capacitor. It is a figure for demonstrating the experimental result. It is a flowchart for demonstrating the heartbeat detection process. It is a figure for demonstrating the modification of a capacitor. It is a figure for demonstrating the vehicle-mounted example of the heart rate signal detection device.

(1) Outline of Embodiment The heartbeat signal detection device 11 (FIG. 2) includes a resonance circuit 1a for detecting a heartbeat and respiration signal due to heartbeat and respiration, and a resonance circuit 1b for detecting a respiration signal due to respiration.
The resonance circuit 1a includes a flat plate type capacitor 3a (FIG. 6) to be mounted at the position of the heart of the subject 10, and the resonance circuit 1b includes a flat plate type capacitor 3b to be mounted at the position of the lungs.

The capacitor 3a has an electrode formed larger than that of the capacitor 3b, and the inner part of the body is defined as a measurement region (hatched portion in FIGS. 5A and 5B) than the capacitor 3b.
As a result, the capacitor 3a detects the beat due to the heartbeat and the movement due to the respiration of the lungs around it as a change in capacitance, and the capacitor 3b detects the movement due to the respiration of the lung as a change in capacitance. To do.

These changes in capacitance appear as changes in the resonance frequency, and the resonance circuit 1a (FIG. 1 (a)) transmits a heartbeat / breathing signal that combines heartbeat and breathing due to the voltage of the coil 5a caused by the change in resonance frequency. Upon detection, the resonant circuit 1b (not shown) detects the breathing signal due to breathing by the voltage of the coil 5b.
The signal processing device 16 (FIG. 2) removes the respiratory component contained in the heartbeat / breathing signal by subtracting the breathing signal from the heartbeat / breathing signal, thereby outputting the heartbeat signal which is the difference between the two.

The heartbeat signal detection device 11 can be mounted on the vehicle to monitor the physical condition of the driver. In this case, if the capacitors 3a and 3b are built in the driver's seat or seat belt, these can be carried out without burdening the driver. Can be attached.

(2) Details of the Embodiment FIG. 1 is a diagram for explaining the operating principle of the resonant circuit 1a according to the present embodiment.
The heartbeat signal detection device 11 (FIG. 2) includes a resonance circuit 1a for detecting a signal (hereinafter referred to as a heartbeat / respiration signal) in which the movement of the subject 10 due to the heartbeat and the movement of the lungs due to the respiration overlap. A resonance circuit 1b for detecting a signal (hereinafter referred to as a respiratory signal) obtained from the movement of the lungs due to respiration is provided, and FIG. 1 shows the configuration of the resonance circuit 1a among these.

Hereinafter, the components for the heartbeat / respiration signal will be represented by the capacitors 3a and the like, and the components for the respiration signal will be represented by the capacitors 3b and the like and b. It will be expressed without subscripts such as capacitor 3.

The resonance circuit 1a is configured by using an RLC series circuit in which a transmitter 6a, a resistor 2a, a capacitor 3a, and a coil 5a are connected in series.
The capacitor 3a is a flat plate type capacitor, and is formed by arranging electrodes 31a and 32a on both sides of the dielectric plate 33a. The electrode 34a will be described later with reference to FIG.
The electrode 31a is formed on the side facing the body surface of the subject 10, and the electrode 32a is formed on the side facing the body surface.

The transmitter 6a is an AC power supply that supplies power to the resonance circuit 1a, one power supply terminal is connected to one terminal of the resistor 2a, the other power supply terminal is grounded, and one terminal of the coil 5a is connected. You are connected.
The other terminal of the resistor 2a is connected to the electrode 31a of the capacitor 3a, and the other terminal of the coil 5a is connected to the electrode 32a.

Here, assuming that the capacitance of the capacitor 3a is R and the inductance of the coil 5a is L, the resonance frequency fr of the resonance circuit 1a is 1 divided by the square root of LC and 2π as shown in the equation (1). It is represented by a value, and in the present embodiment, the resonance frequency fr is set to be about 100 [KHz].
Although the signals from the heartbeat and respiration are weak, they can be magnified and detected by using the resonance phenomenon.

When the capacitor 3a of the resonance circuit 1a configured in this way is attached to the chest of the subject 10 and the transmitter 6a is started, the capacitor 3a is driven by an alternating current.
Then, the capacitor 3a is capacitively coupled (coupling) with the internal organs (blood flow through the heart, lungs, arteries, etc.) and electrostatically (because the shape of the coupled dielectric changes). The capacity changes according to the movement of these organs.
As a result, the resonance frequency of the resonance circuit 1a fluctuates, so that the movement of these organs can be detected by the change in the resonance frequency.

In the prior art of Patent Document 1, the electrode plate connected in parallel with the capacitor is arranged on the chest, whereas in the heartbeat signal detection device 11, the flat plate type capacitor is arranged on the chest as described above.
The phenomenon that the flat plate type capacitor can be installed outside the body to detect the movement inside the body is a phenomenon newly discovered by the inventors of the present application, and the detailed principle of coupling and the equivalent circuit including the human body are currently being enthusiastically elucidated. I'm in the middle of it.

Since the alternating current is conducted through clothes and gaps, the capacitor 3a can be attached while the subject 10 is wearing clothes.
In this case, in the capacitor 3a used in the experiment, since the electrode 31a is exposed, the clothing functions as a dielectric material that separates the electrode 31a from the human body.

In a commonly used heartbeat / respiration detection system, electrodes and the like must be attached directly to the skin, which imposes a heavy burden on the subject 10, but the capacitor 3a may be applied from above while wearing clothes. The mental and physical burden on the subject 10 can be significantly reduced.

The change in the capacitance of the capacitor 3a can be detected from the change in the resonance frequency as in the prior art of Patent Document 1, but the heartbeat signal detection device 11 detects this by the time change of the voltage Vf generated in the coil 5a. To detect. Since one terminal of the coil 5a is grounded, Vf is also the potential of the other terminal.

FIG. 1B shows the frequency characteristics of the resonant circuit 1a. The vertical axis represents the voltage amplitude in [V], and the horizontal axis represents the frequency in [Hz]. Here, the curve representing the frequency characteristic of the resonance circuit 1a will be referred to as a resonance curve.

The resonance curve has a bell shape centered on the resonance frequency, and is constant unless the capacitance of the capacitor 3a changes.
In the case of the resonant circuit 1a, the capacitance changes with the cardiopulmonary activity of the heart and lungs. Therefore, at a certain time point, for example, the curve 21 is formed, and at another time point, for example, the curve 22 is formed. It changes from moment to moment.

In this way, the resonance curve has a bell-shaped shape centered on the resonance frequency at each time, which changes depending on the cardiopulmonary activity, and the change in the resonance frequency (that is, the change in capacitance accompanying the cardiopulmonary activity). The resonance point, width, and height change dynamically accordingly.

With respect to the resonance curve that changes from moment to moment, the heartbeat signal detection device 11 fixes the drive frequency and the amplitude of the output voltage of the transmitter 6a in the vicinity of the resonance frequency of the resonance circuit 1a.
When so-called fixed point observation with fixed voltage and amplitude is performed in this way, cardiopulmonary activity is observed as a potential difference of resonance amplitude 23.

For example, when the drive frequency of the transmitter 6a is fixed at the position of the broken line 25, the amplitude becomes the voltage 27 on the curve 21 and the voltage 28 on the curve 22. The potential difference 23 corresponds to a change in the capacitance of the capacitor 3a, that is, a movement of the heart and lungs.
As described above, in the resonance circuit 1a, since the voltage amplitude changes according to the movement of the heart and lungs, the cardiopulmonary activity can be detected as an electric signal by observing the voltage Vf generated in the coil 5a.

The resonance circuit 1a is designed to resonate at about 100 [KHz], but the drive frequency is changed in this vicinity, and the frequency at which the heartbeat / respiration signal appears most often is manually or automatically scanned and selected. It can also be configured as follows. The same applies to the resonant circuit 1b.

As described above, since the heartbeat signal detection device 11 measures the voltage of the coil 5a instead of the change in the resonance frequency, it is not necessary to precisely adjust the frequency, and the drive frequency may be in the vicinity of the resonance frequency.
This simplifies the configuration of the electric circuit, does not require adjusting the drive frequency for each individual, and is robust (robust) for the measurement of a plurality of subjects 10 having individual differences in physique.

Further, when detecting the frequency, complicated digital signal processing such as FFT (Fast Fourier Transform) is required, the apparatus becomes large and expensive, and a delay due to the processing time also occurs.
On the other hand, since the heartbeat signal detection device 11 measures the change in the voltage of the coil 5a, it does not require calibration for strictly detecting the voltage value, and detects it without delay using a simple analog circuit described later. Processing can be performed.

In addition, in digital signal processing, pulsed signals may not be leveled and detected by integration processing or the like, but the heart rate signal detection device 11 also detects these by an analog circuit and simple digital processing described later. Can be done.
As described above, the heartbeat signal detection device 11 is robust against individual differences in the physique of the subject 10, has a simple circuit configuration, and has a low manufacturing cost, and is therefore suitable for mass production and mounting on a vehicle. There is.
Although the resonance circuit 1a has been described above, the configuration of the resonance circuit 1b is also the same.

FIG. 2 is a diagram for explaining the configuration of the heartbeat signal detection device 11.
The heartbeat signal detection device 11 is a device that detects a heartbeat signal due to a pulse wave, and detects a resonance circuit 1a for detecting a heartbeat / breathing signal, a half-wave rectifying unit 12a, an HPF13a, an LPF14a, an amplifier circuit 15a, and a breathing signal. It is composed of a resonance circuit 1b, a half-wave rectifying unit 12b, an HPF13b, an LPF14b, an amplifier circuit 15b, and a signal processing device 16 that detects a heartbeat signal by differentially processing the heartbeat / breathing signal and the breathing signal.

When the heartbeat signal is filtered by digital processing, the pulsed signal generated momentarily such as arrhythmia is leveled and disappears due to the integration calculation. To prevent this, resonance circuits 1 to The amplifier circuit 15 was composed of an analog circuit.

The half-wave rectifier unit 12 half-wave rectifies the output of the resonance circuit 1. HPF13 and LPF14 are a high-pass filter and a low-pass filter, respectively. The amplifier circuit 15a is an amplifier circuit that amplifies a signal.

In such a measurement, HPF13 and LPF14 are usually used, but in the case of the heartbeat signal detection device 11, it has been found that the measurement can be performed without them. Therefore, in the present embodiment, the normal HPF13 and LPF14 surrounded by the dotted line in FIG. 2 are omitted. As a result, the circuit can be simplified and the cost can be reduced.
Further, when the drive frequencies of the transmitter 6a and the transmitter 6b are the same, one transmitter 6 may be shared by the resonance circuit 1a and the resonance circuit 1b.

The signal processing device 16 calculates the heartbeat signal by digital processing by calculating the difference between the heartbeat / breathing signal detected by the resonance circuit 1a and the breathing signal detected by the resonance circuit 1b.
Since the respiration signal is weaker than the heartbeat respiration signal, the signal processing device 16 amplifies the respiration signal and then performs a subtraction process so that the respiration component is erased from the heartbeat respiration signal.
This amplification was performed by multiplying the real number n by n (n was obtained by an experiment), but it can be performed at a higher speed by performing a bit shift operation.

Further, in the present embodiment, the signal level of the respiration signal is adjusted, but the heartbeat respiration signal or both the heartbeat respiration signal and the respiration signal may be adjusted.
Further, the respiratory signal may be amplified in an analog manner by the amplifier circuit 15b instead of being digitally processed by the signal processing device 16. Doing this reduces digital processing and allows for faster processing. It is also possible to configure the difference circuit with an analog circuit.

As mentioned earlier, in digital processing, the signal may be leveled by integration, but in the case of the signal processing device 16, the respiration signal is simply amplified and subtracted from the heartbeat respiration signal, so the integration is performed. All heartbeat signals including pulsed signals can be output in real time without delay without complicated digital processing including.

FIG. 3 is a diagram for explaining a hardware configuration of the signal processing device 16.
In the signal processing device 16, a CPU (Central Processing Unit) 41, a ROM (Read Only Memory) 42, a RAM (Random Access Memory) 43, an interface 44, an input device 45, an output device 46, a storage device 47, and the like are connected by a bus line. It is composed of.

The CPU 41 operates according to the heartbeat signal detection program stored in the storage device 47, controls the resonance circuits 1 to the amplifier circuit 15, calculates the pulse signal from the detected heartbeat / breathing signal and the breathing signal, and the like.

The ROM 42 is a read-only memory, and stores basic programs, parameters, and the like when the signal processing device 16 operates.
The RAM 43 is a readable and writable memory, and provides a working memory when the CPU 41 processes a heartbeat / respiration signal and a respiration signal to calculate a heartbeat signal.

The interface 44 is an interface for connecting the signal processing device 16 and the amplifier circuits 15a and 15b.
The input device 45 includes, for example, an input device such as a touch panel, a keyboard, or a mouse, and is used when operating the signal processing device 16.
The output device 46 includes a display, a speaker, and the like, and displays a heartbeat signal and outputs an operation sound.

The storage device 47 is configured by using a large-capacity storage medium such as a semiconductor device or a hard disk, and stores an OS (Operating System), a heartbeat signal detection program, detected pulse data, and the like.

FIG. 4 is a diagram for explaining the configuration of the capacitor 3.
4 (a) to 4 (c) are views showing a capacitor 3a, (a) is a surface on the opposite side of the human body side (a surface on the side not facing the human body), and (c) is a surface on the human body side. It represents (the surface on the side facing the human body), and (b) represents the cross section.
As shown in FIG. 4B, the capacitor 3a is made of a dielectric plate 33a made of a square glass epoxy resin or bakelite having a side of about 10 [cm] and a thickness of about 1 [mm]. An electrode 32a made of a copper thin film is formed on the surface opposite to the human body side, and an electrode 31a and an electrode 34a made of a copper thin film are formed on the surface on the human body side.

As shown in FIG. 4A, the electrode 32a has a square shape with a side of about 8 [cm] and is arranged at the center of the dielectric plate 33a. A dielectric plate 33a is exposed on the outside of the periphery of the electrode 32a.
On the other hand, the electrode 31a has the same size and shape as the electrode 32a, and is formed at a position corresponding to the electrode 32a. Further, around the electrode 31a, an electrode 34a having a width of about 1 [cm] is formed in an annular shape across an exposed surface of the dielectric plate 33a.

The electrode 32a and the electrode 31a are connected to the coil 5a and the resistor 2a, respectively, and the electrode 34a is grounded. The resistor 2a may be connected to the electrode 32a, and the coil 5a may be connected to the electrode 31a.
As described above, when the electrode 31a and the electrode 32a are formed in the same shape and the electrode 34a is grounded, good results are obtained, which was found by the inventor of the present application by trial and error.

4 (d) to (f) are views showing a capacitor 3b, (d) is a surface on the opposite side of the human body side (a surface on the side not facing the human body), and (f) is a surface on the human body side. (E) represents a cross section.
The capacitor 3b is configured by using the same member as the capacitor 3a. The thickness of each member of the capacitor 3b is the same as that of the capacitor 3a, but the area of each member is reduced to 25%, and the length of one side is about 5 [cm].
Although the shape of the capacitor 3 has been described above, it is also possible to form the outer shape into a circular shape or an elliptical shape that matches the heart. Further, it is possible to give a three-dimensional shape such as bending the plate surface.
For example, based on the size Q of the heart, the capacitor 3a is formed to have a size equal to or larger than Q, while the capacitor 3b is formed to be smaller than Q.

FIG. 5 is a diagram for explaining the difference in the measurement region depending on the size of the electrode area of the capacitor 3.
According to the experiment of the inventor of the present application, it was found that the larger the area of the electrode, the deeper the body can be used as the measurement region.
FIG. 5A shows a measurement area of the capacitor 3a.
The capacitor 3a is set to a size that covers the heart from outside the body, and as shown schematically by diagonal lines, the capacitor 3a extends to the deep part of the body to the heart as a measurement area of the heart and the surrounding lungs. Detect movement.

FIG. 5B shows the measurement area of the capacitor 3b.
Since the electrode area of the capacitor 3b is smaller than that of the capacitor 3a, the movement of the lungs is detected by setting the shallow part of the body as the measurement area as schematically shown by the diagonal line.

FIG. 6 is a diagram showing an example of mounting the capacitor 3.
In the experiment conducted this time, as shown in the figure, a capacitor 3a was placed at the position of the heart on the front side of the subject 10 from above the clothes, and the position of the lungs shifted from the heart (for example, as shown in FIG. 6). A capacitor 3b was installed at the position of the lung on the right side of the subject 10.

FIG. 7 is a diagram for explaining the experimental results.
FIG. 7A shows a heartbeat / breathing signal 51 by the condenser 3a.
In addition, the subject 10 also measured the electrocardiogram with a normal electrocardiogram monitor at the same time for comparison, and the electrocardiogram 50 by this is also shown in the figure.
The horizontal axis represents the time axis in seconds, which is common to heartbeat / breathing signals and electrocardiograms. The vertical axis on the left side represents the heartbeat / respiration signal, and the vertical axis on the right side represents the value of the electrocardiogram in [mV] units. The same applies to FIGS. 7 (b) and 7 (c).

As shown in FIG. 7A, in the heartbeat / respiration signal 51, a portion that seems to correspond to the R wave of the electrocardiogram 50 and a portion that does not correspond to the R wave are mixed.
Here, the R wave is a pulse-shaped wave (for example, R wave 55) that rises sharply in the electrocardiogram, and a name is given to a characteristic portion of the electrocardiographic waveform such as the S wave.
In the analysis of the electrocardiogram, the measurement of the interval between adjacent R waves, that is, the RR interval is the most important.

FIG. 7B shows the respiration signal 52 due to the capacitor 3b.
There are some heartbeat-like parts, but they are less clear than the heartbeat-breathing signal due to the predominance of respiratory components.
FIG. 7 (c) shows the heartbeat signal 53 generated by the difference between the heartbeat respiration signal and the respiration signal.
As shown in the figure, in the heartbeat signal 53, the peaks 56, 56, ... Of the R waves 55 and 55 are clearly detected, and the RR interval is accurately detected.

FIG. 8 is a flowchart for explaining the heartbeat detection process performed by the signal processing device 16.
The following processing is performed according to the pulse signal detection program stored in the storage device 47 by the CPU 41. It is assumed that the subject 10 is equipped with capacitors 3a and 3b.

First, the CPU 41 communicates with the resonance circuits 1a and 1b via the interface 44, starts the transmitters 6a and 6b, and drives the resonance circuits 1a and 1b (step 5).
As a result, the resonance circuit 1a starts the detection of the heartbeat respiration signal, and the resonance circuit 1b starts the detection of the respiration signal.
These signals are analog-processed by the half-wave rectifier unit 12a to the amplifier circuit 15a and the half-wave rectifier unit 12b to the amplifier circuit 15b, respectively, and then input to the signal processing device 16 via the interface 44.

The CPU 41 samples the heartbeat / respiration signal and the respiration signal input via the interface 44 at a predetermined sampling rate, converts them into digital data, and stores them in the RAM 43 (steps 10 and 15).
At this time, the CPU 41 assigns a detection time to the digitized heartbeat / respiration signal and the respiration signal so that the heartbeat / respiration signal detected at the same time can be associated with the respiration signal in chronological order.

Next, the CPU 41 amplifies the respiratory signal stored in the RAM 43, and stores the amplified respiratory signal in the RAM 43 (step 20).
Next, the CPU 41 reads the corresponding heartbeat / respiration signal in time series and the respiration signal after amplification from the RAM 43, calculates the difference between them, and stores them in the RAM 43 (step 25).
As long as the heartbeat signal can be detected normally, the association of the detection times may be slightly different.

Next, the CPU 41 outputs the difference stored in the RAM 43 to the output device 46 as a heartbeat signal (step 30).
The CPU 41 returns to step 10 when continuing the measurement (step 35; Y), and ends the process after stopping the resonance circuits 1a and 1b when ending the measurement (step 35; N).

FIG. 9 is a diagram for explaining a modification of the capacitor 3a.
The capacitor 3a according to this modification has an electrode 35a having the same size as the electrode 32a via a dielectric (space in the case of the figure) on the outside of the electrode 32a, and the electrode 35a is grounded. There is. Other configurations are the same as those of the capacitor 3a of the embodiment. Similarly, the capacitor 3b also includes an electrode 35b (not shown).
With this configuration, the influence of external electromagnetic noise on the capacitor 3 can be reduced.

FIG. 10 is a diagram for explaining an example of mounting the heartbeat signal detection device 11 on a vehicle.
In the example of FIG. 10A, the capacitor 3b is arranged on the seat belt, and the capacitor 3a is arranged (built-in) on the backrest of the seat.
The capacitor 3b is placed near the seatbelt in contact with the chest of the subject 10 when the seatbelt is fastened, and the capacitor 3a is placed at the heart when the subject 10 sits on the seat. The backrest part near where is located.

When the heartbeat signal detection device 11 is driven, the capacitor 3 and the internal organs of the subject 10 are capacitively coupled to each other via the clothes worn by the subject 10, the material of the seatbelt, the member of the backrest, and the like, and the heartbeat / breathing signal Respiratory signals can be detected.

By deploying the capacitors 3a and 3b in this way, the subject 10 can wear the capacitors 3a and 3b without any consciousness simply by sitting down and wearing the seatbelt, and can be worn for a long period of time over the operation period. Can be detected.
If the electrodes and dielectric of the capacitor 3 are made of a flexible material such as a conductive resin, it can be mounted more comfortably.

The example of FIG. 10B shows an example in which the capacitor 3a is built in the seat belt and the capacitor 3b is built in the backrest of the seat.
Since the three-point seat belt just covers the heart area, if the capacitor 3a is miniaturized to a size that fits in the seat belt, the heart region of the subject 10 can be monitored well.
Further, it is effective to install the capacitor 3b in the vicinity of the lungs displaced from the heart.
Further, in the cases of FIGS. 10A and 10B, if a grounding electrode is attached to the handle so that the user's body is grounded by grasping the handle, electromagnetic noise acting on the human body from the outside is generated. Can be removed, and the detection accuracy of the heartbeat signal is improved.

The signal processing device 16 may be mounted on a vehicle or may be mounted on a server device.
When the signal processing device 16 is realized by a server device, the heartbeat signal detection device 11 includes a transmission / reception device connected to a communication network such as the Internet instead of the heartbeat signal detection device 11, and is detected by the resonance circuits 1a to the amplifier circuit 15a. The heartbeat / breathing signal and the breathing signal detected by the resonance circuits 1b to the amplifier circuit 15b are transmitted to the server device.

The server device calculates the heartbeat signal from the heartbeat signal detection device 11 of the embodiment and the modified example described above.
Such a configuration can be used, for example, to provide a monitoring device at a taxi or tour bus business establishment to monitor the health condition of the driver.
Further, in the server device, not only the heartbeat signal but also the respiratory state of the driver can be monitored by the respiratory signal.
Heartbeat and respiration are indicators that can easily confirm the health condition, but the driver's abnormality can be detected quickly by the heartbeat signal and respiration signal.
Furthermore, it can be expanded to other industries such as railway drivers and aircraft pilots.

According to the embodiment described above, the following effects can be obtained.
(1) The pulse of the subject 10 can be measured by attaching a parallel plate type capacitor.
(2) Since the pulse can be measured through clothes, long-term measurement can be performed without imposing a mental or physical burden on the subject 10.
(3) Although the signal that can be detected by a capacitive electrode such as a capacitor is weak, it is possible to amplify and detect a minute change by resonating using a resonance circuit.
(4) The heartbeat component can be efficiently acquired by taking the difference between the heartbeat breathing signal in which the breathing component and the heartbeat component are mixed and the breathing signal in which the respiratory component is dominant.
(5) It is possible to monitor the health condition of the driver by mounting the vehicle on the vehicle.
(6) By incorporating a capacitor into the seat belt or seat in consideration of the vehicle structure, the sensor arrangement and shape can be optimized.

1 Resonance circuit 2 Resistance 3 Capacitor 5 Coil 6 Transmitter 10 Target person 11 Heartbeat signal detector 12 Half-wave rectifier 13 HPF
14 LPF
15 Amplifier circuit 16 Signal processing device 21, 22 Curve 23 Potential difference 27, 28 Voltage 31, 32, 34, 35 Electrode 33 Dielectric plate 33
41 CPU
42 ROM
43 RAM
44 Interface 45 Input device 46 Output device 47 Storage device 50 Electrocardiogram 51 Heartbeat breathing signal 52 Breathing signal 53 Heartbeat signal 55 R wave 56 Peak

Claims (8)

1. The seating member on which the subject of biological signal detection sits,
   In the seating member, a first capacitor that is installed in the heart region of the subject and is capacitively coupled to an organ reaching the heart region of the subject.
   In the seating member, a second capacitor installed at the lung site of the subject and capacitively coupling with an organ reaching the lung region of the subject,
   A first biological signal based on a temporal change in the capacitance of the first capacitor coupled with capacitance, and a second biological signal based on a temporal change in the capacitance of the second capacitor coupled with capacitance. And, the biological signal acquisition means to acquire,
   A biological signal output means for outputting the acquired first biological signal and the second biological signal,
   A biological signal detection device, characterized in that it is provided with.
2. According to claim 1, at least one of the first capacitor and the second capacitor is installed on the backrest portion of the seating member, and the other is installed on the seat belt portion. The biological signal detection device according to the description.
3. The output first biological signal and the second biological signal are acquired, and the heartbeat signal is obtained by using the difference between the acquired first biological signal and the second biological signal synchronized with the first biological signal. The means of acquiring the heartbeat signal to be acquired,
   A heartbeat signal output means for outputting the acquired heartbeat signal, and
   The biological signal detection device according to claim 1 or 2, wherein the biological signal detection device is provided.
4. A transmission means for transmitting the output first biological signal and the second biological signal to a predetermined server device, and
   The biological signal detection device according to claim 1 or 2, wherein the biological signal detection device is provided.
5. A biological signal receiving means for receiving the first biological signal and the second biological signal from the biological signal detecting device according to claim 4.
   A heartbeat signal acquisition means for acquiring a heartbeat signal using the difference between the received first biological signal and the second biological signal synchronized with the first biological signal.
   A heartbeat signal output means for outputting the acquired heartbeat signal, and
   A heartbeat signal detection server characterized by being equipped with.
6. A vehicle comprising the biological signal detection device according to any one of claims 1 to 4, and having the seating member in the driver's seat.
7. A first biosignal based on a temporal change in the capacity of a first capacitor that is capacitively coupled to an organ reaching the heart region of the subject, which is installed in the heart region of the subject for biological signal detection.
   A living body that acquires a second biological signal based on a temporal change in the capacity of a second capacitor that is capacitively coupled to an organ reaching the lung region of the subject, which is installed at the lung site of the subject. Signal acquisition function and
   The biological signal output function that outputs the acquired first biological signal and the second biological signal, and
   A biological signal detection program realized by a computer.
8. A biological signal receiving function for receiving the first biological signal and the second biological signal from the biological signal detecting device according to claim 4.
   A heartbeat signal acquisition function that acquires a heartbeat signal using the difference between the received first biological signal and the second biological signal synchronized with the first biological signal.
   The heartbeat signal output function that outputs the acquired heartbeat signal and
   A heart rate signal detection program that realizes on a computer.

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