JP7414201B2 - Biometric information acquisition device - Google Patents

Description

The present invention relates to a biological information acquisition device.

BACKGROUND ART Research and development of diagnostic systems based on body-conducted sounds (eg, blood flow sounds, heart sounds, breathing sounds, etc.) and acceleration signals have been progressing for the early detection of respiratory and circulatory system diseases. Clear signals can be easily obtained by collecting blood flow sounds near the wrist, heart sounds near the chest or abdomen, and breathing sounds near the cheeks. However, attaching microphones to three locations and collecting body-conducted sound from each location is time-consuming, costly, and labor-intensive, and places a heavy burden on the subject.

Therefore, as described in Patent Document 1, an acoustic signal separation device that can highly accurately separate a specific component from a mixed acoustic signal sampled at one location has been proposed. Further, as described in Patent Document 2, a sleep diagnosis device has been proposed that obtains biological information of a subject using one acceleration sensor and detects breathing rate and heart rate.

However, in the acoustic signal separation device of Patent Document 1, since the acoustic sensor 11 is attached to the carotid artery epithelium, it takes time and effort to attach it, and there are disadvantages in that it is easy to pick up sounds other than body-conducted sound. Further, the sleep diagnosis device of Patent Document 2 has a problem in that information other than changes in sleeping posture, breathing rate, and heart rate cannot be derived.

Further, in the accelerometer heart rate meter of Patent Document 3 and the heartbeat measuring device of Patent Document 4, the heart rate can be measured by using an acceleration sensor and performing signal processing on the acceleration signal obtained therefrom. However, since the accelerometer heart rate monitor of Patent Document 3 and the heartbeat measuring device of Patent Document 4 directly measure the vibration acceleration generated by the pulsation, the vibration acceleration and gravitational acceleration are mixed, and the pulsation information is not properly measured. There is a problem that it cannot be taken out.

Japanese Patent Application Publication No. 2015-31889 Patent No. 3809847 Patent No. 2849711 Patent No. 3682254

The present invention has been made in view of such problems, and an object of the present invention is to provide a biological information acquisition device that can accurately acquire biological information using a simple method.

A biological information acquisition device according to the present invention is a biological information acquisition device having a small sensor head, the small sensor head comprising :
A mounting part that can be attached to the body of a subject, a body-conducted sound sensor that detects body-conducted sound and acquires an acoustic signal, and a body-conducted sound vibration signal measurement that measures the acoustic signal acquired by the body-conducted sound sensor. means and
A biological information calculating means for calculating biological information from the acoustic signal.

According to the present invention, biological information can be accurately acquired using a simple method.

FIG. 1 is a diagram illustrating the appearance of a biological information acquisition device according to the present invention. It is a figure explaining an attachment part and a body conduction sound sensor. FIG. 2 is a diagram illustrating a biological information acquisition device attached to a subject. It is a figure explaining a body-conducted sound vibration signal measuring means and external equipment.

Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings, but the embodiments are intended to facilitate understanding of the principles of the present invention, and the scope of the present invention is limited to the following: The present invention is not limited to these embodiments, and other embodiments in which the configurations of the following embodiments are appropriately replaced by those skilled in the art are also included within the scope of the present invention.

As shown in FIG. 1, a biological information acquisition device 900 according to the present invention includes a small sensor head 100 and a cable 200 connectable to a terminal.

The small sensor head 100 includes an attachment part 110 that can be attached to the body of a subject, a body-conducted sound sensor 120 that detects body-conducted sound and acquires an acoustic signal, and a body-conducted sound sensor 120 that detects body-conducted sound and acquires an acoustic signal. It includes body-conducted sound vibration signal measuring means 130 for measuring, and biological information calculating means 140 for calculating biological information from the acoustic signal.

(1) Attachment part As shown in FIG. 2, the small sensor head 100 has an attachment part 110 that can be attached to the body of the subject. The attachment part 110 includes a biological skin adhesive protection sheet 111, a biological skin adhesive gel material 112, a soft support 113, and a hard support 114. The biological skin adhesive protection sheet 111 is a removable sheet member that protects the adhesive surface of the biological skin adhesive gel material 112. The biological skin adhesive gel material 112 is made of an adhesive gel that is harmless to the human body, such as silicone gel. The soft support 113 is made of a soft polymer base material such as polyurethane, and improves the feeling of wearing the small sensor head 100 on the subject when it is attached to the subject. The rigid support 114 is formed of a rigid polymer base material such as polystyrene.

(2) Body conduction sound sensor 120
The small sensor head 100 includes a body-conducted sound sensor 120 that detects body-conducted sound and acquires acoustic signals. Body-conducted sound sensor 120 includes a MEMS sensor 121, a filler 122, and a covering material 123.

The MEMS sensor 121 is formed using 3D-MEMS (three-dimensional MEMS) technology in which a silicon wafer is deeply etched by reactive ion etching. The MEMS sensor 121 is equipped with a sensor board, and the sensor board is, for example, GY-521, although it is not particularly limited. GY-521 is a breakout board for utilizing MPU-6050.

The body-conducted sound sensor 120 includes an acceleration sensor that detects the acceleration of the subject's body movement and obtains an acceleration signal. The acceleration sensor has a plurality of different detection axes, and is, for example, a three-axis acceleration sensor.

For example, when the small sensor head 100 is attached to the subject's chest, the chest vibrates every time the subject breathes, which causes the inclination angle of the acceleration sensor in the body-conducted sound sensor 120 to change in accordance with the breathing cycle. . Furthermore, the acceleration sensor inclination angle changes in accordance with the subject's heartbeat. By calculating the inclination angle of the acceleration sensor and performing counting processing, data on the subject's heart rate and breathing rate can be obtained.

The calculation process of the inclination angle from the acceleration data for three axes is not particularly limited, but for example, if the detection axis of the acceleration sensor is defined and the inclination angle of the X-axis with respect to the horizontal plane is defined as φ, φ is It can be calculated using the following formula.

Ｙ軸の水平面に対する傾斜角をρと定義すると、ρは以下の式で計算可能である。

When the inclination angle of the Y-axis with respect to the horizontal plane is defined as ρ, ρ can be calculated using the following formula.

なおａ_ｘ，ａ_ｙ，ａ_ｚは、それぞれ、Ｘ軸、Ｙ軸、Ｚ軸の加速度データである。

Note that a _x , a _y , and a _z are acceleration data of the X axis, Y axis, and Z axis, respectively.

By capturing changes in at least one of the inclination angles φ and ρ of the X-axis and Y-axis with respect to the horizontal plane from the acceleration detected by the acceleration sensor, it is possible to capture slow movements such as breathing, for example. This makes it possible to stably measure heart rate and breathing rate.

Further, the body-conducted sound sensor 120 can also include an angular velocity sensor that detects the angular velocity of the subject's body movement and obtains an angular velocity signal. The angular velocity sensor has a plurality of different detection axes, and is, for example, a three-axis angular velocity sensor. Information about time changes in angular velocity or angle around the detection axis of the angular velocity sensor is acquired from the angular velocity sensor. A temporal change in angular velocity detected by an angular velocity sensor or a temporal change in an angle obtained by integral processing of angular velocity itself represents a posture change. Therefore, by capturing the movement of a predetermined part of the subject in terms of changes in angular velocity or angle, it is possible to capture even slow movements such as breathing, for example.

For example, when the small sensor head 100 is attached to the subject's chest, the chest vibrates every time the subject breathes, which causes the angular velocity data from the angular velocity sensor in the body-conducted sound sensor 120 to change in accordance with the breathing cycle. do. Similarly, the angular velocity data from the angular velocity sensor changes in accordance with the subject's heartbeat. By performing counting processing on the angular velocity data from the angular velocity sensor, data on the subject's heart rate and breathing rate can be obtained. Specifically, the obtained angular velocity data is filtered, the filtered waveform is subjected to threshold processing, the wave number is counted or the wave period is measured, and the result is output as heart rate or respiration rate. .

The body conduction sound sensor 120 may include an acceleration sensor that detects the acceleration of the body conduction of the subject and acquires an acceleration signal, and an angular velocity sensor that detects the angular velocity of the body conduction of the subject and acquires the angular velocity signal. It is possible.

In this embodiment, a configuration using a 3-axis acceleration sensor or a 3-axis angular velocity sensor is shown, but it is also possible to use a 1-axis or 2-axis acceleration sensor or a 1-axis or 2-axis angular velocity sensor. Note that if the direction of the detection axis of the acceleration sensor or angular velocity sensor is parallel to the direction of gravity, the change will be small and difficult to detect, but if the sensor has multiple detection axes, no matter how the subject moves, the direction of gravity will change. Since there are detection axes that are not parallel, it is preferable to use a 3-axis acceleration sensor or a 3-axis angular velocity sensor.

(3) Body-conducted sound vibration signal measuring means The small sensor head 100 has a body-conducted sound vibration signal measuring means 130 that measures the acoustic signal acquired by the body-conducted sound sensor 120.

As shown in FIG. 3, the body-conducted sound vibration signal measuring means 130 includes a vibratory heart rate measuring section 131 that measures the acoustic heart rate, and a vibratory respiration rate measuring section 132 that measures the acoustic respiration rate.

As shown in FIG. 4, when the body-conducted sound vibration signal measuring means 130 receives the acoustic signal from the body-conducted sound sensor 120, the body-conducted sound vibration signal measuring means 130 transmits the acoustic signal at a predetermined time from the transmitting/receiving section 133 to the recording section 134, and sends the acoustic signal to the control section 135. The acoustic conversion signal subjected to Fourier transformation is transmitted to the oscillating heart rate measuring section 131 and the oscillating respiration rate measuring section 132. The control unit 135 is configured to control the operation of the body-conducted sound vibration signal measuring means 130, and includes a memory and a processor. The memory is configured to store computer readable instructions (programs). For example, the memory may include a ROM that stores various programs and the like, a RAM that has multiple work areas that store various programs that are executed by the processor, and the like. Further, the memory may be configured by a flash memory or the like. The processor is, for example, a CPU, MPU and/or GPU. The CPU may be composed of multiple CPU cores. A GPU may be composed of multiple GPU cores. The recording unit 134 is, for example, a storage such as an HDD, an SSD, or a flash memory, and is configured to store programs and various data.

The vibrational heart rate measurement unit 131 removes signals below a predetermined frequency from the received acoustic conversion signal using a high-pass filter, determines the frequency at which the low frequency removed signal peaks, and calculates the acoustic heart rate. In addition, in the oscillatory respiration rate measurement unit 132, a signal having a predetermined frequency or higher is removed from the received acoustic conversion signal using a low-pass filter, and the frequency at which the high frequency removed signal reaches a peak is determined to calculate the acoustic respiration rate.

In this practical embodiment, the body-conducted sound vibration signal measuring means 130 includes a vibratory heart rate measuring section 131 that measures the acoustic heart rate, and a vibratory respiration rate measuring section 132 that measures the acoustic respiration rate. However, the biological information acquisition device according to the present invention is not limited to measuring heart rate and respiration rate, but can also measure information on intestinal peristalsis, for example.

(4) Biological information calculation means As shown in FIG. 3, the small sensor head 100 has a biological information calculation means 140 that calculates biological information from acoustic signals.

The biological information is not particularly limited, but includes, for example, stress index, degree of fatigue, degree of intestinal peristalsis, blood pressure, etc., and preferably includes stress index.

The autonomic nervous system is a system that controls blood circulation, breathing, body temperature regulation, etc. without conscious intervention, and includes the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system works to increase the body's activity level and athletic ability, while the parasympathetic nervous system works to calm the mind and body and suppress and save energy. Heart rate variability affects both the sympathetic and parasympathetic nervous systems. That is, the stress index can be considered using the following formula.

心電図を周波数解析してパワースペクトルにしたときに、LF(Low Frequency)とHF(High Frequency)の２つの領域に分けられる。LF成分は交感神経または副交感神経が活性化しているときに増加し、HF成分は副交感神経が活性化している場合に増加する。そのためLF/HFを指標とすることにより、数値が高いときはストレスがあり低いときはリラックスしていると判定することができる。

When an electrocardiogram is frequency-analyzed into a power spectrum, it can be divided into two regions: LF (Low Frequency) and HF (High Frequency). The LF component increases when the sympathetic or parasympathetic nerves are activated, and the HF component increases when the parasympathetic nerve is activated. Therefore, by using LF/HF as an index, it can be determined that when the value is high, you are stressed, and when the value is low, you are relaxed.

In addition, by extracting high frequency fluctuation components (HF component) corresponding to respiratory fluctuations and low frequency components (LF component) corresponding to Mayer waves, which are blood pressure fluctuations, and comparing the magnitude of the two, we can calculate the stress index. It is also possible to evaluate That is, the biological information calculation means 140 calculates the high frequency fluctuation component (HF component) corresponding to the respiratory fluctuation measured by the oscillating respiration rate measuring section 132 and the Mayer wave (HF component) which is the blood pressure fluctuation measured by the oscillating heart rate measuring section 131. Biological information can be calculated using LF/HF, which is the ratio of the low frequency component (LF component) corresponding to the Mayer wave), as a stress index. For example, evaluate LF/HF using the sum value (integral value) of the intensities of the LF component region (0.05Hz to 0.15Hz) and the HF component region (0.15Hz to 0.40Hz) of the power spectrum. Can be done.

In a relaxed state, that is, when the parasympathetic nervous system is activated, an HF component that reflects respiratory fluctuations and a LF component that reflects blood pressure fluctuations also appear, but in a state of stress, that is, when the sympathetic nervous system is activated. , the HF component decreases while the LF component appears. Therefore, when you are in a relaxed state, the HF component becomes relatively large, so the value of LF/HF becomes small.On the other hand, when you are in a state of stress, the LF component becomes large relative to HF, so the value of LF/HF becomes large. Become.

The calculated biometric information is sent to the connected external device. The external device includes a power supply section 810, a display section 820, and a notification section 830, as shown in FIG. The transmitted biometric information is displayed on the display section 820, and is notified to the measurer by the notification section 830.

It can be used to obtain biological information.

100: Small sensor head
110: Mounting part
111: Biological skin adhesive protection sheet
112: Biological skin adhesive gel material
113: Soft support
114: Rigid support
120: Body conduction sound sensor
121:MEMS sensor
122: Filling material
123: Covering material
130: Body-conducted sound vibration signal measurement means
131: Vibratory heart rate measurement section
132: Vibratory respiration rate measuring section
133: Transmission/reception section
134: Recording Department
135:Control unit
140: Biological information calculation means
200: Cable
810: Power supply section
820:Display section
830: Information department
900: Biological information acquisition device

Claims (2)

A biological information acquisition device having a small sensor head,
The small sensor head is
an attachment part that can be attached to the body of the subject;
A MEMS sensor as an acceleration sensor that detects body-conducted sound and acquires it as an acoustic signal,
Body-conducted sound vibration signal measuring means having a vibratory heart rate measuring section that measures an acoustic heart rate based on the acoustic signal acquired by the MEMS sensor and a vibratory respiration rate measuring section that measures an acoustic respiration rate;
A biological information calculation means for calculating biological information from the acoustic signal ,
The biological information calculation means calculates biological information using respiratory fluctuation/heart rate fluctuation, which is a ratio of respiratory fluctuation measured by the oscillating respiration rate measuring section and heart rate fluctuation measured by the oscillating heart rate measuring section, as a stress index. ,
A biological information acquisition device characterized by : The body-conducted sound vibration signal measuring means includes an acoustic signal converter that performs Fourier transform on the acoustic signal acquired by the MEMS sensor,
The vibration heart rate measuring section includes a low frequency removal section that removes a low frequency component from the acoustic conversion signal obtained by the acoustic signal conversion section, and an acoustic It has an acoustic heart rate calculation section that calculates the heart rate,
The oscillatory respiration rate measurement unit includes a high frequency removal unit that removes high frequency components from the acoustic conversion signal obtained by the acoustic signal conversion unit, and calculates an acoustic respiration rate based on the high frequency removed signal obtained by the high frequency removal unit. 2. The biological information acquisition device according to claim 1, further comprising an acoustic respiration rate calculation unit.