KR20220165509A - Biosignal measuring device and method - Google Patents

Abstract

The present invention relates to a biosignal measuring method for measuring a human body's heart rate and respiration accurately and simply from biosignals received from a plurality of sensors. The method comprises the step of: placing a plurality of sensors around a person's body to detect ballistocardiogram signals and motion signals; allowing a filtering unit to denoise the plurality of ballistocardiogram signals to extract a frequency domain from the same; allowing the filtering unit to synchronize the plurality of ballistocardiogram signals and motion signals based on time; allowing the filtering unit to detect and remove motion artifacts from the multiple ballistocardiogram signals; allowing a signal selecting unit to determine an optimal ballistocardiogram signal from the plurality of ballistocardiogram signals from which the motion artifacts have been removed; and allowing a heart rate and respiration measuring unit to measure a heart rate and respiration by detecting a peak value from the optimal ballistocardiogram signal.

Description

Biosignal measuring device and method {Biosignal measuring device and method}

The present invention relates to a bio-signal measuring device and method, and more particularly, to a bio-signal capable of measuring a bio-signal of a human body by selecting a value most similar to heart rate data and respiration data among signals measured by a plurality of piezo sensors. It relates to measuring devices and methods.

A ballistocardiogram (BCG) is a hand-held weight scale that vibrates in accordance with the heartbeat when the human body is placed on a hand-held weight scale.

Such a ballistic signal represents information about a user's heartbeat as an electrical signal together with an electrocardiogram (ECG) signal. An electrocardiogram (ECG) signal is obtained by attaching electrodes to a part of the body close to the heart and measuring minute electrical signals generated by muscles when the heart beats. The ECG signal is a form that can be analyzed for various heart diseases and is a signal that is mainly measured and analyzed for medical purposes.

On the other hand, the ballistic signal is a signal obtained by measuring minute vibrations of the heartbeat. Although the motion of the heart muscle cannot be expressed as an electrical signal, it contains information about heartbeats per minute.

In addition, the heart ballistic signal has the advantage of being able to measure the user's heartbeat signal unrestrainedly and involuntarily, since there is no need to attach special electrodes or sensors to the body.

The heart ballistic signal is mainly measured while the user is lying on the bed. It can also be measured by detecting minute changes in the weight of the entire bed using a load cell under the bed. It can also be measured through The signals measured at this time include breathing, movement, and noise signals, and factors that affect the signals during measurement include the user's lying posture, the material and thickness of the clothes worn, and the type of mattress.

As described above, the bio-signal detection method using the heart ballistic signal that is currently being applied has a disadvantage in that it requires multiple corrections to calculate more accurate bio-information because it is vulnerable to pressure noise around the actual measurement target, as described above. Therefore, there is a need for a method for accurately measuring bio-signals.

Korean Patent Registration No. 10-1270312

The present invention is to solve the problems of the prior art as described above, and an object of the present invention is to simply and accurately measure the heart rate and respiration of a human body among bio-signals received from a plurality of sensors.

In order to achieve the above object, a biosignal measurement method according to the present invention includes the steps of detecting a ballistocardiogram signal and a movement signal by a plurality of sensors disposed around the human body; denoising, by a filtering unit, to extract a frequency domain from the plurality of ballistic signals; synchronizing, by the filtering unit, the plurality of ballistic signals and the motion signal in time; detecting and removing motion noise from the plurality of ballistic signals by the filtering unit; determining, by a signal selector, an optimal ballistic signal from the plurality of ballistic signals from which the motion noise has been removed; and measuring, by a heart rate and respiration measurement unit, a heart rate and respiration by detecting a peak value in the optimal ballistic signal.

Here, the step of denoising by the filtering unit to extract the frequency domain from the plurality of heart ballistic signals includes separating the plurality of heart ballistic signals into a set of basis functions and performing wavelet transform based on time and scale. ) may be performed.

In addition, the step of denoising by the filtering unit to extract a frequency domain from the plurality of ballistic signals may include a low-pass filter using a band-pass filter to obtain frequencies of 30 Hz or less from the plurality of ballistic signals. The frequency is filtered, and the high-pass filter may filter a frequency of 0.1 Hz or more from the plurality of ballistic signals.

이고, 끝나는 시점은,

의 수식으로 복수의 상기 심탄도 신호 및 상기 움직임 신호를 시간상에서 동기화 하며, 여기서, F_t는 제1센서부의 현재값이며, F_t-1은 제1센서부의 이전 값이고, F_thds는 트리거 시점의 문턱값이고, F_thde는 종료 시점의 문턱값이며, m은 제1센서부의 개수일 수 있다.In addition, in the step of synchronizing the plurality of ballistic signals and the movement signals by the filtering unit in time, when it is assumed that the size of the motion noise removal time is n, the trigger activation time point is:

, and the end point is

The plurality of ballistic signals and the movement signals are synchronized in time by the formula of, where F _t is the current value of the first sensor unit, F _t-1 is the previous value of the first sensor unit, and F _thds is the trigger time is a threshold value of , F _thde is a threshold value at an end point, and m may be the number of first sensor units.

In addition, in a state in which the plurality of heart trajectory signals and the movement signals are synchronized in time, the filtering unit determines that a section in which the slope of the motion signal increases to a positive slope or a negative slope is equal to motion noise and is removed. can

In addition, the step of determining the optimal ballistic signal from the plurality of ballistic signals from which the motion noise has been removed by the signal selection unit calculates a signal to noise ratio based on a power spectrum density. can be determined by

In addition, the signal selector may perform fast Fourier transform on a plurality of the heart ballistic signals, select two ballistic signals with the lowest signal-to-noise ratios among the plurality of heart ballistic signals, and calculate an average.

In addition, the signal selector may apply standardization and normalization to the signal values of the plurality of ballistic trajectory signals to adjust them into signals of the same magnitude, and then apply cross-correlation to the signal values calculated from the signal-to-noise ratio.

In addition, the signal selector may determine the optimal ballistic signal by selecting a ballistic signal having a value similar to or greater than a signal value calculated from the signal-to-noise ratio from among the plurality of ballistic signals.

Meanwhile, a bio-signal measuring method according to the present invention for achieving the above object includes receiving an optimal ballistic signal; And the optimal ballistic signal is denoised to extract a frequency domain from a plurality of ballistocardiogram signals and movement signals by a plurality of sensors disposed around the human body, and , A signal determined by synchronizing the plurality of ballistic signals and the movement signals in time and then detecting and removing motion noise from the plurality of ballistic signals, and the heart rate and respiration measuring unit detects a peak value in the optimal ballistic signal. and measuring heart rate and respiration.

In addition, the step of measuring heart rate and respiration by detecting a peak value from the optimal ballistic trajectory signal by the heart rate and respiration measuring unit detects a peak value in a predetermined frequency domain by applying a fast Fourier transform to the optimal ballistic trajectory signal. can do.

In addition, the predetermined frequency range is 1 to 1.5 Hz, and the heart rate and respiration measurement unit may calculate the heart rate by multiplying the peak value by 60.

On the other hand, in the bio-signal measuring device according to the present invention for achieving the above object, a plurality of sensors disposed around the human body detect ballistocardiogram signals and movement signals, and a filtering unit detects the frequency of the plurality of ballistocardiogram signals. Denoises to extract a region, the filtering unit synchronizes the plurality of ballistic signals and the motion signal in time, the filtering unit detects and removes motion noise from the plurality of ballistic signals, and a transmission module for determining an optimal ballistic trajectory signal from the plurality of ballistic ballistic signals from which the motion noise has been removed; and a receiving module configured to measure heart rate and respiration by the heart rate and respiration measuring unit by detecting a peak value in the optimal ballistic signal.

The bio-signal measurement apparatus and method according to the present invention measures the heart rate and respiration by selecting the channel with the most similar sensor value based on the human heart rate and respiration data received from a plurality of sensors, thereby determining the state of the human heart rate and respiration. can be accurately measured.

In addition, the bio-signal measuring device and method according to the present invention can measure the state of heart rate and breathing just by touching a mat, pad, etc. to the human body without attaching a separate device to the human body, so it is non-stimulating and non-aware. , in the form of non-restraint, the patient to be measured can conveniently use it without feeling repulsive.

1 is a diagram schematically showing a bio-signal measurement system according to an embodiment of the present invention.
2 is a block diagram of a bio-signal measuring device according to an embodiment of the present invention.
3 is a flowchart of a bio-signal measurement method according to an embodiment of the present invention.
4 is a flowchart of a bio-signal measuring method according to an embodiment of the present invention.
5 is a diagram schematically illustrating sensing of an FSR signal in a bio-signal measuring device according to an embodiment of the present invention.
6 is a diagram schematically illustrating calculation of a signal-to-noise ratio using a PSD to determine an optimal ballistic signal in a bio-signal measuring device according to an embodiment of the present invention.
7 is a diagram schematically illustrating calculation of similarity using cross-correlation in order to determine an optimal ballistic signal in a bio-signal measuring device according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, some configurations irrelevant to the gist of the present invention will be omitted or compressed, but the omitted configurations are not necessarily unnecessary in the present invention, and can be combined and used by those skilled in the art to which the present invention belongs. can

<Configuration of biological signal measurement system>

1 is a diagram schematically showing a bio-signal measurement system according to an embodiment of the present invention.

As shown in FIG. 1 , the bio-signal measuring system according to an embodiment of the present invention may include a bio-signal measuring device 1 and a medical server 2 .

The bio-signal measuring device 1 is configured to receive a ballistocardiogram (BCG) signal detected from a patient's body and measure heart rate and respiration. The bio-signal measuring device 1 may measure the patient's heart rate and respiration based on ballistic signals detected by a plurality of sensors. That is, a plurality of sensors provided in the transmission module 10 detects a ballistic trajectory signal from the patient's body, filters noise from the detected ballistic trajectory signal, determines an optimal ballistic trajectory signal, and transmits it to the receiving module 20. And, the receiving module 20 can finally measure the patient's heart rate and respiration through filtering and peak value detection from the optimal ballistic signal. The bio-signal measuring device 1 according to the present invention can measure heart rate and respiration in the patient's body even if it is not fixed to a specific part of the patient's body and only touches the patient's body. Therefore, heart rate and respiration can be measured in a non-stimulating, non-awareness and unrestrained fashion.

The medical server 2 is configured to store information about the patient's heart rate and respiration measured by the bio-signal measuring device 1. The medical server 2 receives information about the patient's heart rate and respiration measured by the bio-signal measuring device 1, and in addition to personal information such as the patient's name, age, height, weight, etc. information can be stored.

<Configuration of bio-signal measuring device>

Hereinafter, the configuration of the bio-signal measuring device 1 according to the present invention will be described with reference to the drawings.

2 is a block diagram of a bio-signal measuring device according to an embodiment of the present invention.

As shown in FIG. 2 , the bio-signal measuring device 1 according to an embodiment of the present invention may include a transmission module 10 and a reception module 20 .

First, the transmission module 10 is a component that detects a biosignal from the patient's body, filters noise from the detected biosignal, determines an optimal signal, and transmits it to the reception module 20 . The transmission module 10 may include a first sensor unit 110 , a second sensor unit 120 , a filtering unit 130 , a signal selection unit 140 and a transmission unit 150 .

The first sensor unit 110 is a component that senses a ballistic signal measured from the patient's body. The first sensor unit 110 may include a plurality of piezoelectric pressure sensors (hereinafter referred to as piezoelectric sensors). That is, the heart trajectory signal of the patient may be measured in a state in which the plurality of piezo sensors are in contact with the patient's body.

Here, the piezo sensor is also referred to as a piezoelectric pressure sensor. This is to detect the voltage generated by the stress by applying the displacement or deformation generated in the elastic body by the pressure to the piezoelectric element. As materials for the piezoelectric element, quartz, Rochelle salt, barium titanate (BaTiO3), PZT (zircon titanate ceramics), PVDF (polyvinylidene fluoride), and the like are used. Since the output impedance is very high, an impedance conversion circuit is required for measurement. Although the sensitivity is very high, because the dielectric polarization is used, the induced voltage is proportional to the time differential of the applied stress, and the voltage decreases with time due to leakage, so the static pressure cannot be measured. It has advantages such as small size, high sensitivity, high speed response, and heat resistance. Therefore, the first sensor unit 110 may measure the heart rate and respiration by measuring the vibration of the pulse wave transmitted by the heartbeat.

The first sensor unit 110 is provided in plurality inside a mat or pad formed in a predetermined area, and may be arranged in a predetermined pattern. For example, six first sensor units 110 may be arranged inside a mat or pad in a 2x3 matrix. Alternatively, 12 first sensor units 110 may be arranged inside a mat or pad in a 3x4 matrix. The arrangement of the first sensor unit 110 may vary depending on implementation.

Here, when the first sensor unit 110 detects the heart ballistic signal, since the voltage at both ends is used to measure the signal, the signal of the high point and the low point can be extracted using DC-offset. In addition, a circuit stabilization buffer circuit may be additionally used to prevent high current.

The second sensor unit 120 is a component that senses the movement of the patient on the mat by measuring the pressure value. The second sensor unit 120 may be provided as a force sender resistor (FSR) sensor.

Here, the FSR sensor is also known as a pressure sensor as a sensor using the property of changing resistance value depending on physical force, weight, and the like. This FSR sensor is a thin film type sensor composed of several layers. The most basic FSR has a layer that creates a spatial gap called a spacer in the middle, and a layer (FPC) on which circuits are printed above and below this space and a film layer (MD film) coated with a conductive material ) is placed. And when force is applied from above, more of the printed layer comes into contact with the film layer coated with the conductive material, reducing the resistance of the sensor. Therefore, the voltage can be measured by the resistance value that changes according to the force.

The second sensor unit 120 detects the movement when the positive slope of the pressure value greatly increases or, conversely, the pressure value greatly decreases with the negative slope on the mat or pad. can detect Alternatively, when movement occurs on the surface of a mat, pad, etc. in the plurality of second sensor units 120, the change in pressure value at the location of the specific second sensor unit 120 greatly increases or decreases, so that the time point at which the movement occurs can detect

Like the first sensor unit 110, the second sensor unit 120 is provided in plurality inside a mat or pad formed in a predetermined area, and may be arranged in a predetermined pattern. For example, six second sensor units 120 may be arranged inside a mat or pad in a 2x3 matrix. Alternatively, 12 second sensor units 120 may be arranged inside a mat or pad in a 3x4 matrix. The arrangement of the first sensor unit 110 may vary depending on implementation. Alternatively, only one may be provided inside a mat or pad.

The filtering unit 130 filters and removes motion artifacts from the plurality of ballistic signals detected by the first sensor unit 110 . Since the heart ballistic signal detected by the first sensor unit 110 may include motion noise when the patient moves, it is necessary to filter and remove it in order to measure the patient's bio-signal. In this case, the filtering unit 130 may remove motion noise by synchronizing the motion signal generated by the second sensor unit 120 with the ballistic signal in time and filtering the time when the motion occurs.

First, the filtering unit 130 uses a wavelet transform and a band-passfilter on a plurality of heart ballistic signals to denoise to extract a frequency domain in a range in which a biosignal is measured. can be performed.

Here, the wavelet transform is a transform method representing time and frequency components of a signal whose frequency components change temporally. In general, the Fourier transform expresses frequency components under the assumption that the signal does not change in time, but the wavelet transform represents signals whose frequency components change in time, such as chirped signals, electrocardiographs (ECGs), and video signals. It is a conversion method used to express time and frequency components for . In this case, a low frequency component can be expressed with a high frequency resolution, and a high frequency component can be converted to a high time resolution.

In addition, the band pass filter is a filter that passes signals of a frequency band between two specific cutoff frequencies without attenuation, but attenuates all other frequencies. For example, in order to reduce the cutting effect, it is designed in a trapezoidal shape given by four frequencies f1, f2, f3, f4 that gradually change the cutoff frequency. It has the characteristics of blocking f1 or less and f4 or more, passing between f2 and f3 without attenuation, and changing linearly between f1 and f2 and between f3 and f4. Such a band pass filter includes a low pass filter and a high pass filter, as is well known.

The filtering unit 130 may utilize a wavelet transform, a low-pass filter, and a high-pass filter to extract range frequency domains for the plurality of ballistic signals sensed by the first sensor unit 110 . Therefore, the filtering unit 130 may filter the ballistic signal received from the first sensor unit 110 in the frequency domain by using the low-pass filter and the high-pass filter.

In addition, when the first sensor unit 110 detects a plurality of ballistic signals, a value of low voltage is received, so that the value of the corresponding ballistic signal filtered in the frequency domain is amplified through an operational amplifier (OP-AMP). There is a need. Accordingly, the filtering unit 130 may amplify the ballistic signal through an operational amplifier to measure the ballistic signal.

In addition, the filtering unit 130 may remove motion noise from the ballistic trajectory signals for a specific time period by synchronizing the filtered plurality of ballistic signals with the motion signal in time.

The signal selection unit 140 is a component that determines an optimal ballistic signal from a plurality of ballistic signals from which motion noise has been removed. The signal selector 140 may calculate and determine a signal to noise ratio based on a power spectrum density (PSD) for a plurality of ballistic signals.

Specifically, the signal selection unit 140 performs a fast Fourier transform on a plurality of ballistic signals from which motion noise has been removed after being filtered, and when the fast Fourier transform is performed in this way, values with strong signals are excluded. Weak signals come out. These signals are noises. For example, assuming that signal channels sensed in sampling units from six first sensor units 110 are assumed, two signal channels having the smallest total signal-to-noise among the six signal channels are selected, and the The average of the signal values can be calculated. This is a primary process for determining the optimal ballistic signal.

Then, assuming that the value calculated from the signal-to-noise ratio is A and the signal values detected in each signal channel are 1 to 6, standardization and normalization are performed on each signal channel for comparison with signal A, that is, cross correlation. through and adjust to a signal of the same magnitude. This cross-correlation is an index representing the correlation between two signals.

Next, when the value of signal A is slid along the X-axis by setting the rear end of the value of A signal and the point of the front end of each signal channel identically, a value similar to or greater than the value of signal A is obtained. It is to select the optimal signal by selecting the signal value with This is a secondary process for determining the optimal ballistic signal.

The transmission unit 150 transmits the optimal ballistic signal determined by the transmission module 10 to the reception module 20 . The transmission unit 150 may be connected to a wired or wireless network to transmit an optimal ballistic signal.

Next, the receiving module 20 is configured to measure heart rate and respiration by detecting a peak value based on the optimal ballistic signal received from the transmitting module 10 . The receiving module 20 may include a receiving unit 210, a heart rate and respiration measuring unit 220, and a transmitting unit 230.

The receiver 210 is a component that receives the optimal ballistic signal transmitted by the transmitter 150 . The receiving unit 210 may be connected to the transmitting unit 150 through a wired or wireless network to receive an optimal ballistic signal.

The heart rate and respiration measuring unit 220 is a component that measures the patient's heart rate and respiration by detecting a peak value in the received optimal heart ballistic signal. The ballistic signal detected by the first sensor unit 110 may be a signal value in which noise of several signals is mixed. For example, if a normal person's respiratory rate is 60 to 96 times, the change in frequency will be a value in the range of 1 to 1.5 Hz. This becomes a measure of respiration. Therefore, after decomposing the ballistic signal detected by the first sensor unit 110 through fast Fourier transform in the range of 1 to 1.5 Hz, the signal value obtained by filtering the noise through analog filtering, and then decomposing each ballistic signal into the highest Detect the frequency value of the signal value. Then, when the highest frequency value (peak value) is multiplied by 60, the heart rate can be calculated.

The transmitter 230 transmits the heart rate and respiration values measured by the heart rate and respiration measurement unit 220 to the medical server 2 . The transmitting unit 230 may be connected to the medical server 2 through a wired or wireless network to transmit heart rate and respiration values.

<How to measure vital signs>

Hereinafter, a bio-signal measuring method according to an embodiment of the present invention will be described with reference to the drawings.

3 is a flowchart of a bio-signal measuring method according to an embodiment of the present invention, and FIG. 4 is a flowchart of a bio-signal measuring method according to an embodiment of the present invention.

As shown in FIGS. 3 and 4 , in the bio-signal measurement method according to the embodiment of the present invention, a plurality of sensors disposed around the human body may initially detect a ballistocardiogram signal and a motion signal. <S30>

Specifically, the first sensor unit 110 is provided as a piezo sensor and can sense a ballistic signal measured from the patient's body. The first sensor unit 110 may measure the heart trajectory signal of the patient while in contact with the patient's body.

In addition, the second sensor unit 120 is provided as an FSR sensor and detects the patient's movement on the mat by measuring the pressure value on the mat on which the patient is lying or on the pad that the patient is attaching to a specific part of the body. pressure can be sensed.

Next, the filtering unit 130 may denoise to extract a frequency domain from the plurality of ballistic signals. <S31>

Specifically, the filtering unit 130 may filter and remove motion noise from the plurality of ballistic signals sensed by the first sensor unit 110 . Here, a wavelet transform may be applied to a plurality of heart ballistic signals, and then a low-pass filter and a high-pass filter may be used to extract a measured range frequency region of the heartbeat data.

Here, the filtering unit 130 may perform wavelet transform based on time and scale by separating a plurality of ballistic signals into a set of basis functions.

The low-pass filter filters frequencies below 30 Hz in the ballistic signal, and the high-pass filter filters frequencies above 0.1 Hz.

In addition, when the first sensor unit 110 detects a plurality of ballistic signals, a value of low voltage is received, so that the value of the corresponding ballistic signal filtered in the frequency domain is amplified through an operational amplifier (OP-AMP). There is a need. Accordingly, the filtering unit 130 may amplify the ballistic signal having a frequency between 0.1 and 30 Hz by a factor of 1 to 400 through an operational amplifier to measure the ballistic signal.

In addition, since the first sensor unit 110 measures the ballistic signal using the voltage at both ends when detecting the ballistic signal, it is possible to extract the signal of the high point and the low point using the DC-offset.

In addition, a buffer circuit for circuit stabilization may be additionally used to prevent high current.

Thereafter, a plurality of ballistic signals and movement signals may be synchronized in time. <S32> This will be described with reference to FIG. 5 .

5 is a diagram schematically illustrating sensing of an FSR signal in a bio-signal measuring device according to an embodiment of the present invention.

When the patient is lying on the mat and the patient moves, such as tossing and turning, heart rate and respiration may not be measured properly. Accordingly, it is possible to accurately measure the patient's heart rate and respiration only when motion noise is removed from the plurality of ballistic signals. Accordingly, the filtering unit 130 may remove motion noise by using the pressure value sensed by the second sensor unit 120 provided inside the mat.

As shown in FIG. 5 , the second sensor unit 120 detects movement on the mat or pad when the positive slope of the pressure value greatly increases or, conversely, the pressure value decreases to a negative slope on the mat or pad. It is possible to detect the time when the movement of the patient occurs.

Alternatively, when movement occurs on the surface of a mat, pad, etc. in the plurality of second sensor units 120, the change in pressure value at the location of the specific second sensor unit 120 greatly increases or decreases, so that the time point at which the movement occurs can detect

Therefore, the filtering unit 130 synchronizes the motion signals detected by the second sensor unit 120 with the plurality of ballistic signals filtered in the frequency domain between 0.1 and 30 Hz in time to synchronize the ballistic signals for a specific time period. noise can be removed.

For example, assuming that the number of first sensor units 110 is 6 and that the size of the motion noise cancellation time of the first sensor unit 110 is n, the activation time of the trigger is as follows.

Here, F _t is a current value of the first sensor unit 110, F _t−1 is a previous value of the first sensor unit 110, and F _thds is a threshold value at the start time.

Also, the ending point is as follows.

Here, F _thde is the threshold value at the end point.

In the example, it has been described assuming that the number of first sensor units 110 is 6, but it may vary according to the number of first sensor units 110 .

Using this equation, a plurality of ballistic signals filtered in the frequency domain between 0.1 and 30 Hz and the motion signal detected by the second sensor unit 120 may be synchronized in time.

Next, motion noise may be detected and removed from the plurality of ballistic signals. <S33>

A plurality of ballistic signals filtered in the frequency domain between 0.1 and 30 Hz synchronized in time are synchronized with the motion signal detected by the second sensor unit 120, and thus the position of motion noise may be detected in the ballistic signal. Accordingly, the filtering unit 130 may remove motion noise from the ballistic signal for a specific period of time.

Thereafter, an optimal ballistic signal may be determined from a plurality of ballistic signals from which motion noise has been removed. <S34> This will be described with reference to FIG. 6 .

6 is a diagram schematically illustrating the determination of an optimal ballistic signal in the bio-signal measuring device according to an embodiment of the present invention.

The signal selector 140 may calculate and determine a signal to noise ratio based on a power spectrum density (PSD) for a plurality of ballistic signals.

Specifically, the signal selection unit 140 performs a fast Fourier transform on a plurality of ballistic signals from which motion noise has been removed after being filtered, and when the fast Fourier transform is performed in this way, values with strong signals are excluded. Weak signals come out. These weak signals are noises. For example, assuming that signal channels sensed in sampling units from six first sensor units 110 are assumed, two signal channels having the lowest total signal-to-noise ratio are selected among the six signal channels, and the signals of these two channels are selected. The average of the values can be calculated. This is a primary process for determining the optimal ballistic signal.

Then, assuming that the signal value calculated from the signal-to-noise ratio is A and the signal values detected in each signal channel of the plurality of ballistic signals are 1 to 6, for comparison with signal A, that is, cross correlation Each signal channel is standardized and normalized and adjusted to a signal of the same magnitude.

Next, when the value of signal A is slid along the X-axis by setting the rear end of the value of A signal and the point of the front end of each signal channel identically, a value similar to or greater than the value of signal A is obtained. It is to select the optimal signal by selecting the signal value with This is a secondary process for determining the optimal ballistic signal.

Finally, the heart rate and respiration can be measured by detecting the peak value in the optimal ballistic signal. <S35>

Specifically, the receiver 210 may receive the optimal ballistic signal transmitted by the transmitter 150 and transmit the signal to the heart rate and respiration measurement unit 220 . Accordingly, the heart rate and respiration measuring unit 220 may measure the patient's heart rate and respiration by detecting a peak value in the received optimal ballistic signal.

The ballistic signal detected by the first sensor unit 110 may be a signal value in which noise of several signals is mixed. For example, if a normal person's respiratory rate is 60 to 96 times, it will be a value in the range of 1 to 1.5 Hz when changed to a frequency. This becomes a measure of respiration. Therefore, after decomposing the ballistic signal detected by the first sensor unit 110 through fast Fourier transform in the range of 1 to 1.5 Hz for noise-filtered signal values through analog filtering, each ballistic signal has the highest Detect the frequency value of the signal value. Then, when the highest frequency value (peak value) is multiplied by 60, the heart rate can be calculated.

As described above, in the present invention, the optimal ballistic signal is determined by receiving ballistic signals from a plurality of sensors, filtering the received plurality of ballistic signals to remove noise, and detecting a peak value in the optimal ballistic signal to treat the patient's condition. Heart rate and breathing can be measured. Since it is possible to measure the patient's body by touching a mat or pad without attaching a separate device to the patient's body, it can provide comfort to the patient in the form of non-stimulation, non-awareness, and non-restraint, and at the same time, accurate measurement is possible. make it possible

The preferred embodiment of the present invention described above has been disclosed for illustrative purposes, and various modifications, changes and additions will be possible to those skilled in the art with ordinary knowledge of the present invention within the spirit and scope of the present invention, and such modifications and changes and additions should be considered to fall within the scope of the claims of the present invention.

1: bio-signal measuring device
10: transmission module
110: first sensor unit
120: second sensor unit
130: filtering unit
140: signal selector
150: transmission unit
20: receiving module
210: receiver
220: heart rate and respiration measuring unit
230: transmission unit
2 : Medical server

Claims (13)

In the biosignal measuring method,
Sensing a ballistocardiogram signal and a motion signal by a plurality of sensors disposed around the human body;
denoising, by a filtering unit, to extract a frequency domain from the plurality of ballistic signals;
synchronizing, by the filtering unit, the plurality of ballistic signals and the motion signal in time;
detecting and removing motion noise from the plurality of ballistic signals by the filtering unit; and
Determining, by a signal selector, an optimal ballistic signal from the plurality of ballistic signals from which the motion noise has been removed;
How to measure vital signs.
According to claim 1,
The step of denoising by the filtering unit to extract a frequency domain from the plurality of ballistic signals,
Separating a plurality of the ballistic signals into a set of basis functions and performing wavelet transform based on time and scale,
How to measure vital signs.
According to claim 1,
The step of denoising by the filtering unit to extract a frequency domain from the plurality of ballistic signals,
Using a band-passfilter, a low-pass filter filters frequencies of 30 Hz or less from the plurality of ballistic signals, and a high-pass filter filters frequencies of 0.1 Hz or more from the plurality of ballistic signals.
How to measure vital signs.
According to claim 1,
Synchronizing, by the filtering unit, the plurality of ballistic signals and the motion signal in time,
Assuming that the size of the motion noise cancellation time is n, the trigger activation time is

ego,
the ending point,

The plurality of ballistic signals and the motion signal are synchronized in time by the formula of
Here, F _t is the current value of the first sensor unit, F _t-1 is the previous value of the first sensor unit, F _thds is the threshold value at the trigger time, F _thde is the threshold value at the end time point, and m is the first The number of sensor parts,
How to measure vital signs.
According to claim 4,
In a state in which the plurality of the heart trajectory signals and the motion signals are synchronized in time, the filtering unit determines that a section in which the slope of the motion signal increases to a positive slope or a negative slope is equal to noise and removes it.
How to measure vital signs.
According to claim 1,
The step of determining the optimal ballistic signal from the plurality of ballistic signals from which the motion noise has been removed by the signal selector,
Determined by calculating the signal to noise ratio based on the power spectrum density,
How to measure vital signs.
According to claim 6,
The signal selector,
Performing Fast Fourier Transform on the plurality of ballistic signals;
Calculating an average by selecting two ballistic signals with the lowest signal-to-noise ratio among the plurality of ballistic signals,
How to measure vital signs.
According to claim 7,
The signal selector,
Standardization and normalization are applied to the signal values of the plurality of ballistic signals to adjust them to signals of the same size, and then cross-correlation is applied with the signal value calculated from the signal-to-noise ratio.
How to measure vital signs.
According to claim 8,
The signal selector,
determining the optimal ballistic signal by selecting a ballistic signal having a value similar to or greater than a signal value calculated from the signal-to-noise ratio from among the plurality of ballistic signals;
How to measure vital signs.
In the biosignal measuring method,
receiving an optimal ballistic signal; and
The optimal ballistic signal,
A plurality of sensors disposed around the human body detect ballistocardiogram signals and movement signals, denoise the plurality of ballistocardiogram signals to extract frequency domains, and perform a plurality of ballistocardiogram signals and A signal determined by synchronizing the motion signal in time and then detecting and removing motion noise from the plurality of ballistic signals;
A heart rate and respiration measurement unit detecting a peak value in the optimal ballistic signal to measure heart rate and respiration,
How to measure vital signs.
According to claim 1,
The step of measuring the heart rate and respiration by the heart rate and respiration measuring unit by detecting a peak value in the optimal ballistic signal,
Detecting a peak value in a predetermined frequency domain by applying fast Fourier transform to the optimal ballistic signal,
How to measure vital signs.
According to claim 11,
The predetermined frequency range is 1 to 1.5 Hz,
The heart rate and respiration measurement unit calculates the heart rate by multiplying the peak value by 60.
How to measure vital signs.
In the bio-signal measuring device,
A plurality of sensors disposed around the human body detect ballistocardiogram signals and motion signals, a filtering unit denoises a plurality of ballistocardiogram signals to extract a frequency domain, and the filtering unit denoises a plurality of ballistocardiogram signals. The ballistic signal and the motion signal are synchronized in time, the filtering unit detects and removes motion noise from the plurality of ballistic signals, and the signal selection unit detects and removes motion noise from the plurality of ballistic signals from which the motion noise has been removed. a transmission module for determining a ballistic signal; and
The heart rate and respiration measurement unit includes a receiving module for measuring heart rate and respiration by detecting a peak value in the optimal ballistic signal.
Bio-signal measuring device.

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