WO2022169021A1 - Waistband-type wearable electrocardiogram measurement apparatus, and method and apparatus for measuring heartbeat using same - Google Patents

Abstract

The present invention relates to a waistband-type wearable electrocardiogram measurement apparatus, and a method and apparatus for measuring a heartbeat using same. The waistband-type wearable electrocardiogram measurement apparatus according to one embodiment of the present invention comprises: an elastic member; and fiber electrodes that are formed on the elastic member and measure an electrocardiogram signal of a user, wherein the fiber electrodes may include a conductive yarn and a metal mixture coated on the conductive yarn.

Description

Waistband type wearable electrocardiogram measuring device and heart rate measuring method and device using same

The present invention relates to a waistband type wearable electrocardiogram measuring device, and more particularly, to a waistband type wearable electrocardiographic measuring device and a method and apparatus for measuring a heartbeat using the same.

A wearable technology capable of continuously measuring biosignals in daily life has been proposed as the most promising continuous electrocardiogram measurement technology. A garment-type ECG measurement system, one of the representative wearable ECG measurement technologies, is manufactured in a way that the system is embedded in clothing. However, most of the measurement systems have been mainly manufactured in the form of high elasticity and close contact with the body in order to improve the quality of the measured signal because they are vulnerable to motion noise.

However, since this shape may cause great discomfort by pressing the user's body for a long time, improvement in user convenience or usability has been continuously required.

The present invention was created to solve the above problems, and an object of the present invention is to provide a waistband-type wearable electrocardiogram measuring device and a heartbeat measuring method and apparatus using the same.

Another object of the present invention is to provide an electrocardiogram measuring device using a fiber electrode coated with a metal mixture.

Objects of the present invention are not limited to the objects mentioned above, and other objects not mentioned will be clearly understood from the description below.

In order to achieve the above objects, a waistband-type wearable electrocardiogram measuring device according to an embodiment of the present invention, an elastic member; and a fiber electrode formed on the elastic member and measuring a user's ECG signal, wherein the fiber electrode may include a conductive yarn and a metal mixture coated on the conductive yarn.

In an embodiment, the fiber electrode may include first to third electrodes, the first electrode may be located on a side surface of the second electrode, and the third electrode may be located below the second electrode. have.

In an embodiment, the waistband-type wearable electrocardiogram measuring device may further include a first fabric positioned between the elastic member and the fiber electrode and having a restoring force.

In an embodiment, the waistband-type wearable electrocardiogram measuring device may further include an interface unit connected to the fiber electrode and transmitting the electrocardiogram signal measured by the fiber electrode to the heart rate measuring device.

In an embodiment, the waistband-type wearable electrocardiogram measuring device includes: a cover member positioned on the interface unit to cover the interface unit; may further include.

In an embodiment, the waistband-type wearable electrocardiogram measuring device further includes; a second fabric that is positioned between the elastic member and the fiber electrode and has no stretch, and one end of the interface unit is formed with the fiber electrode and connected, and the other end of the interface unit may be connected to the heart rate measuring device through the elastic member and the second fabric.

In an embodiment, the electrocardiogram signal is transmitted to a heartbeat measuring device, the electrocardiogram signal is interpolated by the heartbeat measuring device, the interpolated electrocardiogram signal is filtered, and a QRS waveform of the filtered electrocardiogram signal is obtained. The heartbeat interval of the user may be calculated using the method, and the average number of beats per minute may be calculated by moving averaging the heartbeat interval.

Specific details for achieving the above objects will become clear with reference to the embodiments to be described in detail below in conjunction with the accompanying drawings.

However, the present invention is not limited to the embodiments disclosed below, but may be configured in various different forms, and those of ordinary skill in the art to which the present invention pertains ( Hereinafter, "a person skilled in the art") is provided to fully inform the scope of the invention.

According to an embodiment of the present invention, there is no restriction on activity by applying pressure to the upper body or attaching an additional measuring sensor through a waistband type wearable electrocardiogram measuring device. can

The effects of the present invention are not limited to the above-described effects, and potential effects expected by the technical features of the present invention will be clearly understood from the following description.

1 is a view showing a manufacturing process of a fiber electrode according to an embodiment of the present invention.

2A and 2B are diagrams illustrating an example of a fiber electrode according to an embodiment of the present invention.

3A to 3C are diagrams illustrating an image of a fiber electrode according to an embodiment of the present invention.

4A to 4C are diagrams illustrating a wearable electrocardiogram measuring device of a waistband type according to an embodiment of the present invention.

4D is a diagram illustrating an arrangement structure of a fiber electrode according to an embodiment of the present invention.

5 is a diagram illustrating a heart rate measuring system according to an embodiment of the present invention.

6 is a diagram illustrating a heart rate measuring method according to an embodiment of the present invention.

7 is a diagram illustrating a waveform change graph before and after interpolation according to an embodiment of the present invention.

8 is a diagram illustrating a frequency characteristic graph of a band pass filter according to an embodiment of the present invention.

9 is a diagram illustrating an electrocardiogram signal graph before and after filtering according to an embodiment of the present invention.

10 is a diagram illustrating a QRS graph according to an embodiment of the present invention.

11 is a diagram illustrating an RRI graph before and after correction of ectopic beats according to an embodiment of the present invention.

12 is a diagram illustrating a frequency characteristic graph of a moving average filter according to an embodiment of the present invention.

13 is a diagram illustrating an average heart rate graph before and after application of a moving average filter according to an embodiment of the present invention.

14 is a diagram illustrating a functional configuration of a heart rate measuring apparatus according to an embodiment of the present invention.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail.

Various features of the invention disclosed in the claims may be better understood upon consideration of the drawings and detailed description. The apparatus, methods, methods, and various embodiments disclosed herein are provided for purposes of illustration. The disclosed structural and functional features are intended to enable those skilled in the art to specifically practice the various embodiments, and are not intended to limit the scope of the invention. The terms and sentences disclosed are for the purpose of easy-to-understand descriptions of various features of the disclosed invention, and are not intended to limit the scope of the invention.

In describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, a waistband-type wearable electrocardiogram measuring apparatus and a heartbeat measuring method and apparatus using the same according to an embodiment of the present invention will be described.

1 is a view showing a manufacturing process of a fiber electrode according to an embodiment of the present invention. 2A and 2B are diagrams illustrating an example of a fiber electrode according to an embodiment of the present invention.

Referring to FIG. 1 , in the knitting step 110 , for the manufacture of a fiber electrode, PET (polyester) 70 fibers and a diameter of 30

Conductive yarn can be manufactured by covering two strands of m silver wire.

For the elongation recovery rate and body adhesion of the fiber electrode, the fabricated conductive yarn can be mixed with 82% PET and 18% PU (polyurethane) to produce a conductive-based fiber electrode with a stripe structure.

In the screen printing step 120 , a silver compound may be coated on the conductive fiber electrode to improve skin adhesion and measurement accuracy of the conductive fiber electrode.

For example, a silver mixture can be partially coated over a conductive yarn-based fiber electrode via silk screen. Referring to FIG. 2A , it can be seen that the conduction-based fiber electrode is subjected to the coating process of the silver mixture.

In the curing step 130, 100

The silver mixture can be fixed on the fiber electrode by curing at a temperature of In this case, the silver mixture may be coated only on the area where the conductor is knitted in consideration of elasticity, conductivity, adhesion, foreign body feeling, and sewing properties.

Referring to FIG. 2B , enlarged views of the front and side surfaces of the fiber electrode coated with the silver mixture can be seen.

3A to 3C are diagrams illustrating an image of a fiber electrode according to an embodiment of the present invention.

Referring to FIG. 3A , the surface of the fiber electrode before coating of the silver mixture can be confirmed. Conductive yarn-based fiber electrodes are approximately 30

It can be seen that it is composed of m-thick silver yarn and several strands of polyester.

Referring to FIGS. 3B and 3C , the surface ( FIG. 3B ) and the side cross-section ( FIG. 3C ) of the fiber electrode after coating of the silver mixture can be confirmed. It can be seen that the silver mixture is applied on the fiber electrode to a thickness of about 190 to 240 silver threads.

The sheet resistance of the fiber electrode coated with the silver mixture can be measured. In this case, the sheet resistance was measured for a sample that was not coated with the silver mixture and a sample that had been coated with the silver mixture. can measure the sheet resistance.

Since the measurement result may change for each measurement, three measurement positions for each sample are arbitrarily determined to calculate the average sheet resistance, and then the sheet resistance can be measured by repeating 10 times for each position.

As a result, the sheet resistance of the uncoated sample was 202.03

43.05

/sq., whereas the coated surface and the back surface resistance of the coated sample were 0.22 each

0.03

/sq., 0.17

0.02

/sq. It can be confirmed that the sheet resistance is reduced by the silver mixture coating as shown in <Table 1> below.

	without silver compound coating	With silver compound coating (coated side)	With silver compound coating (back side)
Surface resistance( /sq.)	202.0 43.1	0.22 0.03	0.17 0.02

4A to 4C are diagrams illustrating a waistband-type wearable electrocardiogram measuring apparatus 400 according to an embodiment of the present invention. 4D is a diagram illustrating an arrangement structure of a fiber electrode 407 according to an embodiment of the present invention.

4A to 4C , the waistband-type wearable electrocardiogram measuring device 400 includes an elastic member 401 , a first fabric 403 , a second fabric 405 , a fiber electrode 407 , and an interface unit 409 . , a cover member 411 and a fixing part 413 may be included.

In an embodiment, the fiber electrode 407 is formed on the elastic member 401 and may measure the user's ECG signal. For example, the elastic member 401 may be implemented as an elastic band.

That is, according to the present invention, in order to realize an electrocardiogram measuring waistband that can be applied to various sizes and shapes of the human body, a waistband-type electrode can be configured using an elastic member having mobility in the measurement range and the previously manufactured fiber electrode. have.

In one embodiment, the fiber electrode 407 may include a conductive yarn and a metal mixture coated on the conductive yarn. For example, the metal mixture may include a silver compound.

In one embodiment, the first fabric 403 is positioned between the elastic member 401 and the fiber electrode 407 and may be made of a material having a restoring force. For example, the first fabric 403 may be comprised of a spacer mesh fabric.

The electrode is three-dimensionally configured by positioning the first fabric 403 having a restoring force between the elastic member 401 and the fiber electrode 407, thereby improving skin adhesion (contactability).

In one embodiment, the second fabric 405 is positioned between the elastic member 401 and the fiber electrode 407 and may be made of a material without stretch. For example, the second fabric 405 may be comprised of a woven fabric.

In an embodiment, the interface unit 409 may be connected to the fiber electrode 407 and transmit an electrocardiogram signal measured by the fiber electrode 407 to the heart rate measuring device.

For example, the interface unit 409 may be configured as a nickel snap button to interface the fiber electrode 407 and the heart rate measuring device. In this case, in order to prevent the metal part of the snap button from directly contacting the skin, the periphery of the post of the snap button may be covered with a cover member 411 to prevent exposure thereof. For example, the cover member 411 may be formed of a seam tape.

In addition, the non-stretchable second fabric 405 may be positioned between the fiber electrode 407 and the elastic member 401 to prevent deformation of the waistband portion connected to the heart rate measuring device through the snap button.

In an embodiment, the electrocardiogram signal is interpolated by the heartbeat measuring device, the interpolated electrocardiogram signal is filtered, and the user's heartbeat interval is calculated using the QRS waveform of the filtered electrocardiogram signal, the heartbeat rate An average number of beats per minute may be calculated by moving averaging the interval.

In one embodiment, one end of the interface unit 409 is connected to the fiber electrode 407 , and the other end of the interface unit 409 passes through the elastic member 401 and the second fabric 405 to be connected to the heart rate measuring device. can

In an embodiment, the cover member 411 may be positioned on the interface unit 409 to cover the interface unit 409 .

In one embodiment, the fixing part 413 may be configured as a size adjustment hook (hook), it may be arranged on the elastic band 401 to enable two-step size adjustment.

For example, the fiber electrode 407 may be symmetrically disposed at a predetermined distance from a center front line on a clothing construction for interfacing with the heart rate measuring device. The interfacing unit 409 may be disposed based on a center front line.

Referring to FIG. 4D , the fiber electrode 407 may include first to third electrodes 421 , 422 , and 423 . In this case, the first electrode 421 may be located on a side surface of the second electrode 422 , and the third electrode 423 may be located below the second electrode 422 .

In an embodiment, the first to third electrodes 421 , 422 , and 423 may be disposed by a modified limb leads method.

In this case, lead I is the potential difference between the first electrode 421 and the second electrode 422 , lead II is the potential difference between the first electrode 421 and the third electrode 423 , and lead III is the first It may be induced by a potential difference between the second electrode 422 and the third electrode 423 .

Lead II is most similar to the direction of electrical conduction of the heart and can measure the highest amplitude electrocardiogram. Lead II can be expressed as a vector sum of horizontal and vertical directions, and this can be defined as leads I and III.

The vector corresponding to lead II can also be expressed as the sum of vectors I' and III', and in this case, the potential difference between the lower extremities can be measured through lead I'. This induction method may have an advantage in that it does not apply pressure to the upper body or attach an additional measurement sensor, so there are few restrictions on activity.

Referring to FIGS. 4A to 4D , in various embodiments of the present invention, the electrocardiogram measuring apparatus 400 has more configurations than those described in FIGS. 4A to 4D because the configurations described in FIGS. 4A to 4D are not essential. Or, it may be implemented with fewer configurations.

5 is a diagram illustrating a heart rate measuring system 500 according to an embodiment of the present invention.

Referring to FIG. 5 , the heart rate measuring system 500 may include an electrocardiogram measuring device 510 , a heart rate measuring device 520 , and a terminal device 530 .

The electrocardiogram measuring apparatus 510 may acquire an electrocardiogram signal from a waistband electrocardiogram fiber electrode.

The heartbeat measuring device 520 may receive an electrocardiogram signal from the electrocardiogram measuring device 510 and transmit it to the terminal device 530 . The terminal device 530 may display the transmitted ECG signal in a real-time graph format and store it as a file.

Also, the heartbeat measuring apparatus 520 may transmit heartbeat rate information calculated from the electrocardiogram signal to the terminal device 530 . The terminal device 530 may display the transmitted heart rate information.

Referring to FIG. 5 , in various embodiments of the present invention, the heart rate measurement system 500 has more configurations than the configurations described in FIG. 5 , or fewer configurations because the configurations described in FIG. 5 are not essential. It can be implemented by having

6 is a diagram illustrating a heart rate measuring method according to an embodiment of the present invention. In an embodiment, each step of FIG. 6 may be performed by the heart rate measuring device 520 .

Referring to FIG. 6 , step S612 is a step of interpolating an electrocardiogram signal.

Step S614 is a step of primary filtering the interpolated ECG signal using a high pass filter.

Step S616 is a step of secondarily filtering the firstly filtered ECG signal using a band pass filter.

In an embodiment, steps S612 to S616 may be configured as pre-processing steps.

Step S622 is a step of detecting the QRS waveform of the second-filtered ECG signal.

Step S624 is a step of correcting an ectopic beat of the QRS waveform.

Step S626 is a step of calculating a heartbeat interval (RRI) from the corrected QRS waveform.

In an embodiment, steps S622 to S626 may consist of heart rate estimation.

Step S632 is a step of calculating the average number of beats per minute by moving averaging the heartbeat interval.

In one embodiment, step S632 may be configured as a post-processing step.

7 is a diagram illustrating a waveform change graph before and after interpolation according to an embodiment of the present invention.

Referring to FIG. 7 , in order to interpolate packet loss occurring during the transmission of an electrocardiogram signal, it is confirmed that the waveform distortion caused by the non-uniform data transmission rate is improved by storing and interpolating the time data at the time the data is acquired. can

8 is a diagram illustrating a frequency characteristic graph of a band pass filter according to an embodiment of the present invention. 9 is a diagram illustrating an electrocardiogram signal graph before and after filtering according to an embodiment of the present invention.

Referring to FIGS. 8 and 9 , since the ECG signal may be greatly affected by respiration or motion noise, filtering may be required in the pre-processing step.

In this case, a band-pass filter may be used to remove low-frequency and high-frequency noise. The band pass filter may include a Finite Impulse Response (FIR) filter having a pass band of 5-35 Hz.

10 is a diagram illustrating a QRS graph according to an embodiment of the present invention.

Referring to FIG. 10 , the QRS waveform of the ECG signal may be detected using the Pan-Tompkins algorithm, but is not limited thereto.

Since the detected QRS waveform may contain false positives or false negatives, such as false positives, false positives can be corrected by manual calibration. Correction of false detection can be performed using the pole detection GUI.

11 is a diagram illustrating an RRI graph before and after correction of ectopic beats according to an embodiment of the present invention.

Referring to FIG. 11 , heart rate interval (RRI) calculation and ectopic compensation may be performed.

RRI can be calculated from the detected and calibrated QRS waveform. For example, the RRI can be calculated through the difference between the temporal positions of the QRS waveform.

At this time, when the QRS waveform is lost, a phenomenon in which the RRI becomes too large (false negative) or too small (false positive) may occur, such as when an ectopic beat occurs, which may cause an error in the calculation of the heart rate. Therefore, compensation for the lost RRI may be performed.

For example, the algorithm proposed by Morelli et al. may be used for RRI compensation, but is not limited thereto. In this algorithm, the number of lost beats can be estimated from the length of the ectopic beat section and the average beat interval, and beats can be generated based on this.

12 is a diagram illustrating a frequency characteristic graph of a moving average filter according to an embodiment of the present invention. 13 is a diagram illustrating an average heart rate graph before and after application of a moving average filter according to an embodiment of the present invention.

12 and 13 , a moving averaging filter for estimating the heart rate may be used.

For example, the heart rate HR may be calculated by taking the reciprocal of the RRI. However, when the heart rate is calculated using the above formula for every RRI, it can be seen that the HR has a very rapid change due to a subtle error in the QRS position during detection. For example, if the QRS position is measured out of 50 ms due to a detection error, an error of approximately 5 bpm may occur based on a heart rate of 72 beats per minute.

Thus, an average of n adjacent beats is provided to provide an average beat, for example, a 5-point moving average filter may be used to average five beats to calculate an average bpm. The coefficients of the moving average filter used can be expressed as [0.2, 0.2, 0.2, 0.2, 0.2].

In one embodiment, a performance evaluation of heart rate estimation may be performed. The heart rate measurement performance according to the present invention may be compared with the heart rate per minute of the ECG measured by the existing reference ECG measurement system.

The ECG signal and the reference ECG signal measured using the heartbeat measurement system 500 according to the present invention were simultaneously measured, and may be acquired at 2 kHz for 6 minutes in a comfortable position in which the user lies on the bed.

The average, standard deviation, and root mean square error (RMSE) of heart rates calculated from the ECG signal obtained through the heartbeat measurement system 500 according to the present invention and the reference ECG signal may be calculated.

Also, the heart rate estimation performance may be evaluated by comparing the heart rate measured by the heart rate measuring system 500 according to the present invention with the HR measured by the reference system. At this time, as the evaluation criteria, the mean and standard deviation, and the RMSE between the two measurement methods are compared, and it can be checked whether the trend can be well followed when estimating the real-time heart rate.

The heart rate measurement performance of the heart rate measurement system 500 according to the present invention and the heart rate per minute of the ECG signal measured by the reference ECG measurement system may be evaluated.

Referring to <Table 2> below, as a result of obtaining QRS of the heart rate measuring system 500 according to the present invention, it can be seen that 350 out of a total of 406 beats are normally received and have a loss rate of 13.6%.

Parameter	Value
Total beats	406
true positive	350
false positive	0
false negative	56
Loss(%)	13.6

Table 3 below shows the final performance of the heart rate measuring system 500 according to the present invention, and from this result, it can be confirmed that the heart rate measuring system 500 according to the present invention has an RMSE of about 2.7 bpm compared to the reference system. In addition, since the difference between the simple average bpm is only 0.2 bpm, it may be possible to estimate the heart rate almost similar to the reference system.

	Biopac	Waist-band type wireless ECG monitoring system
Mean ± SD (bpm)	67.2 2.9	67.0 3.7
RMSE (bpm)	2.7

14 is a diagram illustrating a functional configuration of a heart rate measuring apparatus 520 according to an embodiment of the present invention.

Referring to FIG. 14 , the heartbeat measuring apparatus 520 may include an acquisition unit 1410 , a control unit 1420 , and a storage unit 1430 .

The acquisition unit 1410 may acquire the user's ECG signal from the ECG measuring apparatus 510 .

The acquisition unit 1410 may include a commercial analog front-end (AFE) module for measuring an electrocardiogram. In an embodiment, the acquisition unit 1410 is a one-channel AFE that amplifies the electrocardiogram and performs analog-to-digital converter (ADC), and may have a 16-bit ADC resolution.

The controller 1420 may calculate heart rate data based on the user's ECG signal.

In an embodiment, the controller 1420 may include at least one processor or microprocessor, or may be a part of the processor. Also, the controller 1420 may be referred to as a communication processor (CP). The controller 1420 may control the operation of the heart rate measuring apparatus 520 according to various embodiments of the present disclosure.

The communication unit 1430 may transmit the electrocardiogram data and heart rate data received from the control unit 1420 to the terminal device 530 .

In an embodiment, the communication unit 1410 may include at least one of a wired communication module and a wireless communication module. For example, the communication unit 1410 may include a Bluetooth communication module. All or part of the communication unit 1410 may be referred to as a 'transmitter', 'receiver', or 'transceiver'.

Referring to FIG. 14 , in various embodiments of the present disclosure, the heartbeat measuring apparatus 520 does not necessarily include the components described in FIG. 14 , and thus has more components than those described in FIG. 14 , or fewer components. It can be implemented by having

The above description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention.

The various embodiments disclosed herein may be performed out of order, and may be performed simultaneously or separately.

In an embodiment, at least one step may be omitted or added in each figure described herein, may be performed in the reverse order, or may be performed simultaneously.

The embodiments disclosed in the present specification are not intended to limit the technical spirit of the present invention, but to illustrate, and the scope of the present invention is not limited by these embodiments.

The protection scope of the present invention should be construed by the claims, and all technical ideas within the scope equivalent thereto should be understood to be included in the scope of the present invention.

Claims (7)

1. elastic member; and

   a fiber electrode formed on the elastic member and measuring the user's ECG signal;

   including,

   The fiber electrode comprises a conductive yarn and a metal mixture coated on the conductive yarn,

   A waistband-type wearable electrocardiogram device.
2. According to claim 1,

   The fiber electrode includes first to third electrodes,

   The first electrode is located on the side of the second electrode,

   The third electrode is located below the second electrode,

   A waistband-type wearable electrocardiogram device.
3. According to claim 1,

   a first fabric positioned between the elastic member and the fiber electrode and having a restoring force;

   further comprising,

   A waistband-type wearable electrocardiogram device.
4. According to claim 1,

   an interface unit connected to the fiber electrode and transmitting an electrocardiogram signal measured by the fiber electrode to the heart rate measuring device;

   further comprising,

   A waistband-type wearable electrocardiogram device.
5. 5. The method of claim 4,

   a cover member positioned on the interface unit and covering the interface unit;

   further comprising,

   A waistband-type wearable electrocardiogram device.
6. 5. The method of claim 4,

   a second fabric positioned between the elastic member and the fiber electrode and having no stretch;

   further comprising,

   One end of the interface unit is connected to the fiber electrode,

   The other end of the interface unit is connected to the heart rate measuring device through the elastic member and the second fabric,

   A waistband-type wearable electrocardiogram device.
7. According to claim 1,

   The electrocardiogram signal is transmitted to a heart rate measuring device,

   By the heartbeat measuring device, the electrocardiogram signal is interpolated, the interpolated electrocardiogram signal is filtered, and the heartbeat interval of the user is calculated using the QRS waveform of the filtered electrocardiogram signal, and the heartbeat rate The average beats per minute is calculated by moving averaging the interval,

   A waistband-type wearable electrocardiogram device.

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