KR20240025267A - Apparatus and method for measuring pulse transit time - Google Patents

Abstract

The pulse wave transmission time measuring device includes a radar signal receiver that receives a radar signal projected and reflected from the ultra-wideband radar to the user's chest, a first heart rate waveform detector that detects the first heartbeat waveform of the chest based on the radar signal, and a user A second heart rate waveform receiver that receives the second heart rate waveform of the user's wrist measured from a smart wristband worn on the wrist, and a pulse wave transmission time that detects the pulse wave transmission time based on the first heart rate waveform and the second heart rate waveform. Includes a detection unit.

Description

Apparatus and method for measuring pulse wave transit time {APPARATUS AND METHOD FOR MEASURING PULSE TRANSIT TIME}

The present invention relates to a pulse wave transit time measuring device and method, and more specifically, to a pulse wave transit time measuring device and method for measuring the pulse wave transit time between the user's chest and wrist.

When the aortic valve opens due to ventricular contraction and a stroke volume of blood is ejected into the aorta, the pressure in the aorta reaches its maximum value, and as blood flow progresses to the extremities, a pulsatile wave is transmitted. It takes time for the pulse wave from the base (proximal point, close to the heart) to reach the distal point (distal point, far from the heart), and the delay time of this pulse wave is called pulse transit time (PTT). I call. PTT is a factor that can determine the stiffness of arterial blood vessels and is also used to estimate blood pressure non-invasively. The most common way to measure PTT is to utilize the time difference between the R peak of the electrocardiogram (ECG) and the feature point of the photo-plethysmograph (PPG). These conventional methods directly measure ECG, PPG, or arterial pressure to measure PTT, but these methods involve attaching several electrodes to the body, which has the problem of poor accessibility and convenience for users in daily life.

The technical problem to be achieved by the present invention is to measure the user's heart rate waveform in a non-contact manner using a non-contact ultra-wideband radar, and to determine the pulse wave transmission time by measuring the delay time between the heart rate waveform of the chest and the heart rate waveform of the wrist in a simple manner. To provide an apparatus and method for detecting pulse wave transit time.

One embodiment of the present invention is used to implement cuffless blood pressure (Cuffless Blood Pressure) measurement, which can eliminate the discomfort caused by wearing a cuff felt by the person being measured, and can easily measure blood pressure during daily life. The purpose is to provide a device and method for measuring pulse wave transit time.

The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

In order to achieve the above technical problem, a pulse wave transit time measuring device according to an embodiment of the present invention includes a radar signal receiver that receives a radar signal projected and reflected from the user's chest from an ultra-wideband radar, and the radar signal based on the radar signal. A first heart rate waveform detector that detects the first heart rate waveform of the chest, a second heart rate waveform receiver that receives the second heart rate waveform of the user's wrist measured from a smart wristband worn on the user's wrist, and the first heart rate waveform and the and a pulse wave transit time detection unit that detects the pulse wave transit time based on the second heartbeat waveform.

A method of measuring pulse wave propagation time according to an embodiment of the present invention includes detecting the first heart rate waveform of the user's chest based on a radar signal collected non-contactly from the user's body through an ultra-wideband radar, mounted on the user's wrist. detecting a second heart rate waveform of the user's wrist through a smart wristband and detecting the user's pulse wave transmission time based on the first heart rate waveform and the second heart rate waveform through a pulse wave transmission time measuring device. Includes steps.

An apparatus and method for measuring pulse wave transmission time according to an embodiment can measure the user's heart rate waveform in a non-contact manner using a non-contact ultra-wideband radar, and calculate the delay time between the heart rate waveform of the chest and the heart rate waveform of the wrist in a simple method. Based on this, the pulse wave transmission time can be measured, improving user accessibility and convenience.

The pulse wave transmission time measuring device and method according to one embodiment are used to implement cuffless blood pressure measurement, eliminating the discomfort caused by wearing a cuff felt by the person being measured, and making it easy to use during daily life. Blood pressure can be measured.

An apparatus and method for measuring pulse wave transmission time according to an embodiment can provide convenience in monitoring blood pressure and cardiac activity of healthy people as well as patients during daily life.

The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the description or claims of the present invention.

1 is a diagram showing a system for measuring pulse wave transit time according to an embodiment.
FIG. 2 is a block diagram showing the pulse wave transit time measuring device of FIG. 1 according to an embodiment.
FIG. 3 is a block diagram showing the first heart rate waveform detector of FIG. 2 according to an embodiment.
FIG. 4 is a block diagram showing the pulse wave transit time detector of FIG. 2 according to an embodiment.
Figure 5 is a graph showing a first frame and a first frameset according to one embodiment.
FIG. 6 is a diagram showing a process for detecting a first heart rate waveform in a first frame according to an embodiment.
Figure 7 is graphs showing a second frame and a second frameset according to one embodiment.
Figure 8 is a graph showing a first heart rate waveform and a second heart rate waveform according to an embodiment.
FIG. 9 is a diagram showing a graph in which a first heart rate waveform and a second heart rate waveform are synchronized according to an embodiment.
Figure 10 is a flowchart showing a method of measuring pulse wave transit time according to an embodiment.
Figure 11 is a flowchart showing a method of measuring pulse wave transit time according to an embodiment.

Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention may be implemented in various different forms and, therefore, is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this means not only "directly connected" but also "indirectly connected" with another member in between. "Includes cases where it is. Additionally, when a part is said to “include” a certain component, this does not mean that other components are excluded, but that other components can be added, unless specifically stated to the contrary.

The terms used herein are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to indicate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

In this specification, “module” includes a unit comprised of hardware, software, or firmware, and may be used interchangeably with terms such as logic, logic block, component, or circuit, for example. A module may be an integrated part, a minimum unit that performs one or more functions, or a part thereof. For example, the module may be composed of an application-specific integrated circuit (ASIC).

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

1 is a diagram showing a system for measuring pulse wave transit time according to an embodiment.

The pulse wave transit time measuring system according to one embodiment includes a pulse wave transit time measuring device 100, an ultra-wideband radar 200, and a smart wristband 300. The pulse wave transmission time measurement system according to one embodiment obtains heart rate information from the user's chest in a non-contact manner using a smartphone equipped with an ultra-wide band (UWB) radar 200, and uses a smart wrist band. (300) Alternatively, after obtaining heart rate information from the user's wrist using a smart watch, the pulse wave transmission time between them can be measured using the pulse wave transmission time measuring device 100.

The pulse wave transit time measurement device 100 may be mounted together with the ultra-wideband radar 200 in a user terminal such as a smartphone. The pulse wave transit time measurement device 100 and the ultra-wideband radar 200 mounted on the user terminal can exchange necessary information with each other.

Here, the user terminal can be a smart device equipped with a processor, memory, and communication functions, such as a smartphone, tablet PC, note PC, or desktop. Alternatively, it can be a dedicated device, kiosk, or point of care (POC) equipment with display and input capabilities. The user terminal may provide information measured through the ultra-wideband radar 200 and the smart wristband 300 to the pulse wave propagation time measuring device 100 through a wired or wireless network.

The transceiver and antenna of the ultra-wideband radar 200 are small in size, so they can be mounted on user terminals such as smartphones. Recently, commercialized user terminals have been released equipped with an ultra-wideband radar 200, so heart rate information can be obtained from the user's chest 10, which corresponds to the proximal point, in a non-contact manner. In addition, the ultra-wideband radar 200 emits power that can reach a distance of several meters, so when the user terminal is pointed at the user's chest 10, minute movements of the heartbeat can be captured.

The smart wristband 300 can optically measure heart rate at the wrist. The smart wristband 300 can obtain heart rate information from the distal end corresponding to the user's wrist. Here, the smart wristband 300 includes a smart band and a smart watch.

The smart wristband 300 can communicate with the user terminal through Bluetooth, etc., and can provide heart rate information including the heart rate waveform of the heart rate signal of the user's wrist to the device 100 for measuring the pulse wave transmission time of the user terminal.

The ultra-wideband radar 200 may be a radar using ultra-wideband (UWB). Ultra-wideband (UWB) is a wireless communication technology that transmits large amounts of information at low power over a very wide band compared to existing spectrum. For example, the ultra-wideband radar 200 uses a wireless communication technology capable of transmitting at a speed of 100 to 500M per second using a GHz-wide frequency band, allowing large-capacity videos to be transmitted perfectly without shaking or loss, and the transmission distance It reaches 1km, which is 10 times longer than Bluetooth's 100m. The ultra-wideband radar 200 uses very narrow pulses of several nano or pico seconds and can be used without interference with existing communication systems or frequency restrictions.

The ultra-wideband radar 200 is capable of transmitting and receiving a relatively large number of pulse signals containing detection target information in broadband frequency components, thereby increasing the measurement accuracy of the detection range and distinguishing the type and shape of the object to be detected by frequency characteristics. It is possible to provide flexibility in information processing according to weather conditions and the detection angle of the radar system. The ultra-wideband radar 200 includes a transmitting and receiving antenna, an impulse signal generator, and an impulse detector. In one embodiment, the transmitting and receiving antennas can be configured in a pattern on a substrate and thus can be mounted flat on the outermost case surface of the user terminal.

In one embodiment, the ultra-wideband radar 200 adjusts the transmission/reception antenna to point toward the user's chest 10 to receive a radar signal from the user's chest 10 and detect heart rate information. Information on the heart rate of the user's chest 10 may be obtained through a radar signal in the form of a radar pulse.

For example, in order for the ultra-wideband radar 200 to obtain heart rate information from the user's chest 10, the antenna installed on the smartphone equipped with the ultra-wideband radar 200 is directed toward the chest and the opening angle of the antenna ( A person's upper body must be included within the opening angle.

The pulse wave propagation time measuring device 100 may detect the first heartbeat waveform of the user's chest 10 based on a radar pulse containing information on the heartbeat of the user's chest measured from the ultra-wideband radar 200. The pulse wave transmission time measuring device 100 may detect the second heart rate waveform of the user's wrist using information on the heart rate of the user's wrist measured from the smart wrist band 300.

The pulse wave transit time measuring device 100 can detect the pulse wave transit time (PTT, pulse transit time) within the user's body based on the first heart beat waveform and the second heart beat waveform.

FIG. 2 is a block diagram showing the pulse wave transit time measuring device of FIG. 1 according to an embodiment.

Referring to FIG. 2, the pulse wave transit time measuring device 100 includes a radar signal receiver 110, a first heart rate waveform detector 120, a second heart rate waveform receiver 130, a pulse wave transit time detector 140, and a control unit ( 150) may be included.

The radar signal receiver 110 may receive a radar signal projected and reflected from the ultra-wideband radar 200 to the user's chest 10 (see FIG. 1). The radar signal receiver 110 may collect pulse-type radar signals received from the reception antenna of the ultra-wideband radar 200.

In one embodiment, when pulses emitted from the ultra-wideband radar 200 are projected toward the human body, the phase of the pulses reflected from the rib cage and collected by the antenna at the moment the body surface of the rib cage moves due to breathing or heart rate is of time. It changes continuously according to the flow. Accordingly, the ultra-wideband radar 200 can detect breathing or heart rate based on the change trend of the phase difference. However, since the phase change caused by body movement is much larger than that caused by breathing or heart rate, the changes caused by breathing or heart rate may be buried by those caused by body movement. Therefore, when there is movement such as tossing and turning, breathing and heart rate are monitored. It is difficult to detect. Therefore, when measuring the heart rate of the user's chest 10 through the ultra-wideband radar 200, the user is required not to make any major movements for more than a few seconds.

The first heart rate waveform detector 120 converts the received radar signal into a digital signal frame and accumulates the frames at regular time intervals to create a frameset. The first heart rate waveform detection unit 120 can measure the phase change due to the user's heart rate in time series through the frameset and detect the first heart rate waveform in the user's chest based on this. A detailed description is provided with reference to FIG. 3 .

The second heart rate waveform receiver 130 may receive the second heart rate waveform of the user's wrist measured from the smart wristband 300 (see FIG. 1) worn on the user's wrist. The smart wristband 300 can optically extract the heart rate waveform of the user's wrist directly from the user's wrist. That is, the second heart rate waveform receiver 130 may receive heart rate information of the user's wrist including the second heart rate waveform from the smart wristband 300.

The pulse wave transit time detection unit 140 may detect the pulse wave transit time based on the first heart rate waveform detected from the first heart rate waveform detector 120 and the second heart beat waveform received from the second heart rate waveform receiver 130. . In one embodiment, the pulse wave transmission time detector 140 may calculate the delay time between the first heart rate waveform and the second heart rate waveform and detect the pulse wave transmission time from the user's chest to the wrist based on the calculated delay time. . A detailed description is provided with reference to FIG. 4 .

The control unit 150 may control signals between the first heart rate waveform detection unit 120, the second heart rate waveform reception unit 130, and the pulse wave transit time detection unit 140.

FIG. 3 is a block diagram showing the first heart rate waveform detector of FIG. 2 according to an embodiment.

Referring to FIG. 3, the first heart rate waveform detection unit 120 includes a radar signal processing unit 210, a first frameset generation unit 220, a second frameset generation unit 230, and a filtering unit 240. can do.

The radar signal processing unit 210 may process the pulse-type radar signal received from the ultra-wideband radar 200 (see FIG. 1) into digital form. The digital signal may be a first frame in the form of data. The first frame may include an index indicating the amplitude and the distance between the antenna and the user's chest.

The first frameset generator 220 may remove noise components through a band-pass filter that allows the first frames to pass only a specific band, and generate a first frameset in which the first frames are accumulated at regular time intervals. The first frameset may include amplitude, distance to chest index, and time data.

The second frameset generator 230 may generate a second frameset through Chirp Z-transform based on the first frameset.

The filtering unit 240 may include a band-pass filter that selectively allows each time series data to pass through a specific band in order to extract only components related to the user's heart rate from the time series data of the second frameset. Here, a specific band that extracts only components related to the user's heart rate may be a band ranging from 1 Hz to 3 Hz.

FIG. 4 is a block diagram showing the pulse wave transit time detector of FIG. 2 according to an embodiment.

Referring to FIG. 4 , the pulse wave transit time detection unit 140 may include a synchronization unit 310 and a pulse wave transit time calculation unit 320.

The synchronization unit 310 may synchronize the time axis of the first heart rate waveform and the time axis of the second heart rate waveform. The synchronization unit 310 performs a process in which the smart wristband (300, see FIG. 1) measures the second heart rate waveform for a certain period of time, the ultra-wideband radar (200, see FIG. 1), and the first heart rate waveform detector (120, see FIG. 2). Reference) can match the measurement reference time between the smart wristband 300 and the ultra-wideband radar 200 so that the process of detecting the first heart rate waveform from the user's chest (10, see FIG. 1) can be synchronized. there is. That is, the synchronization unit 310 can align the first heart rate waveform and the second heart rate waveform on the same time axis.

The pulse wave transmission time calculation unit 320 detects the first peak of the first heart beat waveform and the second peak of the second heart beat waveform, which are different points where the same heartbeat occurs, and the delay time between the first peak and the second peak. The average value can be calculated by measuring.

For example, the pulse wave transmission time calculation unit 320 extracts each heart rate waveform from the user's chest and wrist aligned on the same time axis, and then selects the first peak and the second peak at different times when the same heart beat occurs. , and the delay time between the first peak and the second peak can be detected. That is, the pulse wave transfer time calculation unit 320 measures the delay times between the first and second peaks corresponding to each other within the aligned first and second heart beat waveforms and calculates the average of these as the pulse wave transfer time. can be decided.

Figure 5 is a graph showing a first frame and a first frameset according to one embodiment. Figure 5a shows the first frame and Figure 5b shows the first frameset.

In FIG. 5A, the vertical axis of the first frame may correspond to the amplitude of a radio wave including a plurality of peaks. The horizontal axis of the first frame may be an index representing each sampler of the transceiver. That is, the horizontal axis may correspond to the distance in a straight line connecting the antenna of the ultra-wideband radar (200, see FIG. 1) and the target user's chest (10, see FIG. 1) on a plane. For example, the larger the number of the index where the maximum peak is located, the farther the user's chest 10 is located from the antenna of the ultra-wideband radar 200, and the smaller the number, the closer the antenna is to the user's chest 10. It can mean.

In Figure 5b, the first frame is a band-pass filter that selectively passes only components of a specific bandwidth (e.g., 2.3 GHz) based on the center frequency (e.g., 6.8 GHz) of the pulse, which is a radar signal. -pass filter) to remove noise components. Figure 5b shows a first frameset created by filtering each of the first frames and then accumulating them. That is, the first frameset may be generated by accumulating a certain number (eg, 512, 1024, 2048, etc.) of the first frames that have passed the filter at regular time intervals. FIG. 6 is a diagram showing a process for detecting a first heart rate waveform in a first frame according to an embodiment.

In FIG. 6, the second frameset generator 230 (see FIG. 3) converts a plurality of first frames from the first frameset 61 through Chirp Z-Transform to generate a plurality of second frames. A second frameset (62, 63) including these can be created. The plurality of second framesets 62, 63 may be a plurality of amplitude spectra. When a plurality of amplitude spectra are accumulated and arranged on the time axis, a change in the position of the spectral peak corresponding to a change in the phase of the frame around the center frequency of the ultra-wideband radar (200, see FIG. 1) is revealed over time. The second frameset 63 is a graph that shows the second frameset 62 by expressing time direction components according to time series. That is, the second frameset 63 shows time series data. Since the first frames of the first frameset 61 and their amplitude spectra correspond one-to-one, the length of the newly created second framesets 62 and 63 in the time axis direction will be the same as that of the first frameset 61. You can.

The filtering unit 240 may perform filtering to selectively pass the time series data of each frequency through the frequency of a specific band in order to extract only heart rate components from the second framesets 62 and 63. For example, a band pass filter (BPF) can selectively pass a specific band of 1 Hz to 3 Hz to exclude various noises other than the phase caused by the heart rate and generate a third frameset 64 that has only data on heart rate components. there is. After selecting the time series data with the largest amplitude in the third frame set 64 and removing noise, a heart rate waveform is obtained.

Figure 7 is a graph showing a second frame set and a third frame set according to one embodiment.

FIG. 7(a) is a diagram showing the second frameset (62, 63, see FIG. 6) created in FIG. 6, and FIG. 7(b) is a diagram showing the third frameset (64, see FIG. 6) created in FIG. 6. ) This is a picture showing. Figure 7(a) shows an amplitude spectrum including frequency components other than the heart rate component on the frequency axis (y-axis) and the time axis (x-axis). Figure 7(b) shows the third frame set containing only heart rate components through a band pass filter (BPF) on the frequency axis (y-axis) and the time axis (x-axis).

In FIG. 7(b), it can be seen that the phase change due to heartbeat appears most prominently in time series data near the center frequency (e.g., 6.8 GHz) of the ultra-wideband radar 200 (see FIG. 1). For example, in order to obtain representative time series data that best reveals the impact of heart rate, time series data corresponding to 64 frequencies centered on the center frequency are selected as candidates. And among these, the one with the greatest amplitude change can be selected as representative time series data. Its waveform can be shown in Figure 8(a).

Figure 8 is a graph showing a first heart rate waveform and a second heart rate waveform according to an embodiment. Figure 8(a) shows a first heart rate waveform according to one embodiment. Figure 8(b) shows a second heart rate waveform according to one embodiment.

In Figure 8(a), the waveform of the time series data can be regarded as a heartbeat waveform, with each peak corresponding to an actual heartbeat.

In Figure 8(b), the waveform can be considered that of a heartbeat, with each peak corresponding to an actual heartbeat. A smart wristband 300 (see FIG. 1) including a smart watch and/or a smart band extracts a second heart rate waveform containing information on the user's heart rate by an optical method, for example, a photoplethysmography sensor ( Photoplethysmogram (PPG) may be used.

FIG. 9 is a diagram showing a graph in which a first heart rate waveform and a second heart rate waveform are synchronized according to an embodiment.

As explained with reference to FIG. 4, the synchronization unit 310 may synchronize the time axis of the first heart rate waveform and the time axis of the second heart rate waveform. Figure 9 shows graphs for the first heart rate waveform and the second heart rate waveform arranged up and down. Graphs for each of the first heart rate waveform and the second heart rate waveform are normalized and displayed. In Figure 9, it can be seen that a certain time delay occurs between the first heart rate waveform obtained from the chest and the second heart rate waveform obtained from the wrist. More specifically, peaks determined to have occurred at the same heart rate are extracted from each graph, the time delay between each extracted peak is measured, the average value of the delay time is detected, and the pulse wave transmission time is obtained. For example, a first peak may be extracted from a graph of a first heart rate waveform and a second peak corresponding to the first peak may be extracted from a graph of a second heart rate waveform. The delay time between the first peak and the second peak may correspond to the pulse wave propagation time. The user's pulse wave transmission time can be detected by calculating the average value of a plurality of delay times.

Figure 10 is a flowchart showing a method of measuring pulse wave transit time according to an embodiment.

In FIG. 10 , the pulse wave transmission time measurement method may detect the first heartbeat waveform of the user's chest based on a radar signal non-contactly collected from the user's body through an ultra-wideband radar (step S100). In one embodiment, the user places a user terminal, such as a smartphone equipped with an ultra-wideband radar, toward the user's chest and detects the first heart rate waveform of the user's chest by projecting a radar signal to the user's chest in a non-contact manner. You can.

The pulse wave transmission time measurement method can detect the second heart rate waveform of the user's wrist through a smart wrist band worn on the user's wrist (step S200). In one embodiment, the smart wristband can optically detect the second heart rate waveform of the user's wrist.

The pulse wave transmission time measurement method can detect the first heart beat waveform of the chest based on the radar signal reflected from the user's chest (step S300). In one embodiment, the pulse wave transit time measurement method may use chirp transform to generate an amplitude spectrum frame set corresponding to the user's heart rate and extract only the user's heart rate components through filtering.

The pulse wave transit time measurement method may detect the user's pulse wave transit time based on the first heart beat waveform and the second heart beat waveform through a pulse wave transit time measuring device (step S400). In one embodiment, the pulse wave transit time measurement method extracts a first peak for a specific heart beat from the first heart rate waveform of the chest and extracts a second peak for the same heart beat as the specific heart rate from the second heart rate waveform of the wrist to create a pulse wave transit time measurement method. The delay time between the first peak and the second peak can be detected. The detected delay time may be detected for multiple different peaks for the same heartbeat, and the average value may be determined by the user's pulse wave transmission time. In one embodiment, the method of measuring the pulse wave transit time includes the first peak and the second peak of the first heart beat waveform, which are different points where the same heart beat occurs after the synchronization step of matching the time axis of the first heart beat waveform and the time axis of the second heart beat waveform. The second peak of the heart rate waveform can be detected.

Figure 11 is a flowchart showing a method of measuring pulse wave transit time according to an embodiment. Figure 11 shows steps in which the first heart rate waveform detection unit detects the first heart rate waveform.

The first heart rate waveform detector may detect the first heart rate waveform of the chest based on the radar signal. The first heart rate waveform detector may process the radar signal received from the ultra-wideband radar and convert it into a first frame, which is digital data (step S310).

The first heart rate waveform detector may filter the first frame to only components of a specific bandwidth and generate a first frameset in which the first frames are accumulated at regular time intervals (step S320). For example, the first heart rate waveform detector is a band-pass filter that selectively passes only components with a specific bandwidth of 2.3 GHz for each first frame based on 6.8 GHz, the center frequency of the pulse of the radar signal. Noise components can be removed by passing through .

The first heart rate waveform detector may generate a second frameset composed of a plurality of second frames having an amplitude spectrum through Chirp Z-transform based on the first frameset (step S330).

The first heart rate waveform detector may perform filtering to selectively pass only the frequencies of a specific band on the time series data of each frequency in order to extract only the heart rate component from the second frame set (step S340). In one embodiment, the first heart rate waveform detector extracts the amplitude over time at a plurality of frequencies centered on the center frequency of the ultra-wideband radar, and the change in amplitude is the largest among the amplitudes at the extracted plurality of frequencies. A large amplitude can be selected and determined as the user's first heartbeat waveform.

Each component, such as a module or program, according to an embodiment of the present invention may be composed of a single or a plurality of sub-components, and some of these sub-components may be omitted or other sub-components may be added. may be included. Some components (modules or programs) may be integrated into one entity and perform the same or similar functions performed by each corresponding component before integration. Operations performed by modules, programs, or other components according to embodiments of the present invention are executed sequentially, in parallel, repeatedly, or heuristically, or at least some operations are executed in a different order, omitted, or other operations are added. It can be.

The description of the present invention described above is for illustrative purposes, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. will be. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as unitary may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

10: User chest
100: Pulse wave transit time measurement device
110: Radar signal receiver
120: First heartbeat waveform detection unit
130: Second heart rate waveform receiver
140: Pulse wave transmission time detection unit

Claims (10)

In the pulse wave transit time measuring device,
A radar signal receiver that receives a radar signal projected and reflected from the ultra-wideband radar to the user's chest;
a first heart rate waveform detection unit that detects a first heart rate waveform of the chest based on the received radar signal;
a second heart rate waveform receiver that receives a second heart rate waveform measured at the user's wrist from a smart wristband worn on the user's wrist; and
a pulse wave transit time detector that detects a pulse wave transit time based on the first heart beat waveform and the second heart beat waveform;
A pulse wave transit time measuring device comprising: According to paragraph 1,
The pulse wave transit time detection unit calculates a delay time between the first heartbeat waveform and the second heartbeat waveform and detects the pulse wave transit time of the user based on the calculated delay time. According to paragraph 2,
The first heart rate waveform detection unit includes a radar signal processing unit that processes the radar signal of the user's chest collected from the ultra-wideband radar and converts it into a first frame, which is digital data;
a first frameset generator that removes noise components by passing the first frames through a band-pass filter and generates a first frameset by accumulating the first frames at regular time intervals;
a second frameset generator that generates a second frameset including a plurality of second frames by converting the first frameset through chirp Z-transform; and
a filtering unit that filters time series data for each frequency to selectively pass only frequencies in a specific band in order to extract only heart rate components from the second frameset;
A pulse wave transit time measuring device comprising: According to paragraph 3,
A pulse wave transit time measuring device in which the specific band is 1Hz to 3Hz. According to paragraph 2,
The pulse wave transmission time detection unit includes a synchronization unit that synchronizes the time axis of the first heart rate waveform and the time axis of the second heart rate waveform; and
Detect the first peak of the first heart rate waveform and the second peak of the second heart rate waveform, which are different points where the same heartbeat occurs, measure the delay time between the first peak and the second peak, and calculate the average value. A pulse wave transit time calculation unit that calculates;
A pulse wave transit time measuring device comprising:
In the method of measuring the pulse wave transit time by a pulse wave transit time measuring device,
detecting, by the pulse wave transit time measuring device, a first heart rate waveform of the user's chest based on a radar signal non-contactly collected from the user's body through an ultra-wideband radar;
detecting a second heart rate waveform of the user's wrist through a smart wristband in which the pulse wave transmission time measuring device is mounted on the user's wrist and is electrically connected to the ultra-wideband radar; and
detecting, by the pulse wave transit time measuring device, the pulse wave transit time of the user based on the first heart rate waveform and the second heart rate waveform;
A method of measuring pulse wave transit time including. According to clause 6,
The step of detecting the user's pulse wave transmission time is,
A radar signal receiving unit receiving the radar signal;
A first heart rate waveform detection unit detecting a first heart rate waveform of the chest based on the radar signal;
A second heart rate waveform receiving unit receiving the second heart rate waveform; and
A pulse wave transfer time detection unit calculating a delay time between the first heart beat waveform and the second heart beat waveform of the wrist and detecting the pulse wave transfer time based on the calculated delay time;
A method of measuring pulse wave transit time including. In clause 7,
The step of detecting the first heart rate waveform of the chest by the first heart rate waveform detector based on the radar signal,
Processing the radar signal received from the ultra-wideband radar and converting it into a first frame that is digital data;
filtering only components of a specific bandwidth from the first frame and generating a first frameset by accumulating the first frames at regular time intervals;
Generating a second frameset composed of a plurality of second frames having an amplitude spectrum through chirp Z-transform based on the first frameset; and
performing filtering to selectively pass only frequencies in a specific band on time series data of each frequency to extract only heart rate components from the second frameset;
A method of measuring pulse wave transit time including. The method of claim 8, wherein the first heart rate waveform detection unit detects the first heart rate waveform,
The amplitude over time at a plurality of frequencies is extracted centering on the center frequency of the ultra-wideband radar, and the amplitude with the largest change in amplitude is selected among the amplitudes at the extracted plural frequencies. 1 Steps to determine based on heart rate waveform
A method for measuring pulse wave transit time further comprising: The method of claim 7, wherein the pulse wave transmission time detector detecting the pulse wave transmission time based on the delay time comprises:
A synchronization step of matching the time axis of the first heart rate waveform with the time axis of the second heart rate waveform; and
Detect the first peak of the first heart rate waveform and the second peak of the second heart rate waveform, which are different points where the same heartbeat occurs, measure the delay time between the first peak and the second peak, and calculate the average value. calculating step;
A method of measuring pulse wave transit time including.

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