KR101916591B1 - A bio-information determination apparatus and method using principal component analysis of radar signal - Google Patents

Abstract

Disclosed are an apparatus for determining biometric information using principal component analysis of a radar signal and a method thereof. The method for determining biometric information of a target using principal component analysis includes the steps of: generating a frame set by accumulating a single frame formed by superimposing radar pulses reflected from the target for measuring a heartbeat according to a predetermined reception time; setting a region of interest based on time series data with a characteristic similar to the heartbeat of the target among the time series data included in the generated frame set; acquiring one time series data for extracting the heartbeat of the target by performing the principal component analysis on time series data of samplers included in the set region of interest; removing a noise component by using a frequency of the acquired one time series data; and extracting heartbeat information of the target using the one time series data from which the noise component is removed. Accordingly, the present invention can detect the changes of a heartbeat frequency and the heartbeat in a time domain.

Description

Field of the Invention [0001] The present invention relates to a biological information determining apparatus and a biological information determining method using principal component analysis of a radar signal,

More particularly, the present invention relates to a biometric information determination apparatus and method using principal component analysis of a radar signal, and more particularly, to a biometric information determination apparatus and method using principal component analysis of a radar signal, The present invention relates to an apparatus and a method for detecting a change in a heart rate and a heart rate of a heart.

Radar technology has been used to detect distant targets in aeronautical and military applications, or to measure distances to targets. In recent years, attempts have been made to acquire non-invasive and non-contact biological information such as pulse, heartbeat, and respiration from a close-range person using radar technology.

An impulse radar and a CW Doppler radar may be used as a radar technique for acquiring biometric information of a person. These two types of radar technology have different application areas because of differences in power consumption, target detection distance, and spatial resolution.

Among them, UWB (Ultra Wide Band) impulse radar has advantages of low risk of overexposure of electromagnetic wave and low power consumption when used in human body. In addition, the UWB impulse radar has excellent characteristics in terms of coexistence with peripheral devices, and is superior in spatial resolution compared to other methods, and can be considered as a method suitable for acquiring human biometric information.

In order to extract non-invasive and non-invasive human biometric information in this way, a study focusing on radar signals in the frequency domain is mainly focused on analysis of conventional studies using impulse radar. However, if the radar signal is processed in the frequency domain, it is impossible to observe a change in the short-term characteristics in the time domain. In addition, in the case of a heartbeat distributed in a narrow and low frequency band, The problem of increasing the signal acquisition time occurs.

In the present invention, a new radar signal processing method capable of accurately extracting the heartbeat frequency of human biometric information using a UWB impulse radar and accurately detecting the change in heartbeat in the time domain is proposed .
Prior Art 1: Ershad Sharifahmadian and Alireza Ahmadian. &Quot; Adaptive signal processing algorithm for remote detection of heart rate (HR) using ultra-wideband waveforms based on principal component analysis ", 31st Annual International Conference of the IEEE EMBS, IEEE, Sept. 2009. pp.5717-5720.
Prior Art 2: Korean Patent Publication KR10-2016-0148904 (2016-12-27)

The present invention provides an apparatus and method for detecting a change in a heart rate and a heart rate in a time domain by performing Principal Component Analysis on time series data of a frame set generated through a radar signal.

A method of determining a biometric information of a target using principal component analysis according to an embodiment of the present invention includes accumulating a single frame formed by superimposing radar pulses reflected from a target for measuring a heartbeat according to a predetermined reception time, ); Setting a region of interest based on time-series data having characteristics similar to a heartbeat of the target among the time-series data included in the generated frame set; Obtaining one time series data for extracting a heartbeat of the target by performing Principal Component Analysis on time series data of samplers included in the set region of interest; Removing a noise component using the obtained frequency of one time series data; And extracting the heartbeat information of the target using one time series data from which the noise component is removed.

And converting the generated frame set into binary data based on a predetermined criterion, wherein the setting step includes setting a phase change pattern of the frame set converted into the binary data to a predetermined level or higher The area of interest can be set based on the time series data.

The removing step may remove a noise component included in the one time series data by using a dominant frequency determined from the obtained one time series data.

The extracting may calculate a frequency of a heartbeat for the target using a time interval between peak components of one time-series data from which the noise component is removed.

A target biometric information determination apparatus using a principal component analysis according to an exemplary embodiment of the present invention includes a processor for signal processing a single frame formed by overlapping radar pulses reflected from a target for measuring a heart beat, A frame set is generated by accumulating a single frame formed by superimposing radar pulses reflected from a target to be measured according to a predetermined reception time, and generates a frame set based on the heartbeat of the target A time series data for extracting a heartbeat of the target by performing a principal component analysis on time series data of samplers included in the set region of interest based on time series data having similar characteristics, , And the acquired one The noise component is removed using the frequency of the time series data, and the heartbeat information of the target can be extracted using one time series data from which the noise components are removed.

Wherein the processor converts the generated frame set into binary data based on a predetermined criterion, and generates, based on the time series data of the phase set by the heartbeat of the time series data of the frame set converted into the binary data, Can be set.

The processor may remove a noise component included in the one time series data using a dominant frequency determined from the obtained one time series data.

The processor may calculate a frequency of a heartbeat for the target using a time interval between peak components of one time-series data from which the noise component is removed.

According to an embodiment of the present invention, principal component analysis is performed on the time series data of the frame set generated through the radar signal to detect the change in the heart rate frequency and heart rate in the time domain.

1 is a view showing a biological information determination system using a radar signal according to an embodiment of the present invention.
2 is a diagram illustrating a method of generating a frame set according to an embodiment of the present invention.
3 is a flowchart illustrating a method of determining biometric information using principal component analysis of a radar signal according to an exemplary embodiment of the present invention.
4 is a diagram illustrating an example of converting a frame set according to an embodiment of the present invention into binary data.
FIG. 5 is a diagram illustrating an example of restored heartbeat information through principal component analysis according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a biological information determination system using a radar signal according to an embodiment of the present invention.

In order to determine the biometric information of the target 110, the biometric information determination apparatus 100 may project a radar signal toward a direction in which the target 110 is positioned using a transmission antenna. At this time, the transmission radar signal projected through the transmission antenna may be a pulse-shaped radar signal. For example, the transmitted radar signal may be a radar signal in the form of a low-risk, low-power UWB impulse to the human body. At this time, a frequency characteristic such as a center frequency and a bandwidth of a UWB impulse type radar signal projected through the biological information determination apparatus 100 is defined as a standard.

The biometric information determination apparatus 100 can determine the biometric information of the target 110 using the received radar signal that is reflected from the target 110 and collected through the reception antenna. At this time, the biometric information determination apparatus 100 can measure the change in the short-term characteristics of the biometric information according to the time, by analyzing the received radar signal in the time domain, unlike the conventional technique of analyzing the received radar signal in the frequency domain. Various bio-information of the target 110 can be measured using a radar signal, but the present invention provides a method of measuring the heartbeat information among them.

2 is a diagram illustrating a method of generating a frame set according to an embodiment of the present invention.

The transmission radar signal projected from the biological information determination apparatus 100 may be in the form of a pulse whose width is extremely narrow on the time axis as shown in FIG. The biological information determination apparatus 100 can project a transmission radar signal of this type to the target 110 at regular time intervals using a transmission antenna.

The biometric information determination apparatus 100 can collect the radar signal reflected from the target 110 using the receiving antenna. At this time, the biological information determination apparatus 100 may collect the reception radar signal through the reception antenna according to a predetermined time. The received radar signal collected via the receive antenna may be a signal in the form of a superposition of multiple radar pulses.

The biological information determination apparatus 100 may convert the reception radar signal collected through the reception antenna into digital data. At this time, the receiving radar signal collected through the receiving antenna can be converted into digital data by being sampled using a plurality of samplers. In the present invention, a receiving radar signal converted into digital data is referred to as a frame.

FIG. 2 (b) shows the shape of a single frame in the present invention. In this case, the sampler index axis corresponding to the horizontal axis represents the number of each sampler index, and the signal amplitude axis corresponding to the vertical axis represents the voltage of the radar signal collected through the receiving antenna. At this time, each sampler index number may be proportional to the distance from the radar antenna to the target 110. For example, the larger the sampler index number, the greater the distance from the radar antenna to the target 110.

The biometric information determination apparatus 100 may generate and use a frame set in which a plurality of single frames are accumulated in accordance with the flow of time in order to efficiently extract the heart rate frequency of the target 110 from the received radar signal. At this time, a plurality of single frames to be accumulated can be used in units of n power of 2, such as 512, 1024, and so on.

Specifically, FIG. 2C shows a form of a frame set in the present invention. The frame set has a form in which the size of the received radar signal is expressed on a plane formed by the sampled index axis and the time axis. That is, the frame set can be represented by a data structure of a two-dimensional matrix.

For example, suppose that the biometric information determination apparatus 100 supports 256 samplers. The sampler index axis of the frameset can then be composed of 256. And that the bioinformation determination apparatus 100 acquires 512 reception radar signals at 20 ms intervals. Then, since a single frame collected every 20ms interval accumulates in the time axis direction to constitute a frame set, the time axis is composed of 512 unit time (0.02 second), and one frame set is generated by receiving radar signal collected for 10.24 seconds . Such a frame set is not limited to the above example, but may be changed into various values according to needs and uses.

The frame set generated through the biometric information determination apparatus 100 includes biometric information of the target 110. Particularly, the data showing the largest fluctuation among the data in the time axis direction included in the frame set represents information about respiration of the target 110. That is, as shown in FIG. 2 (c), a large variation in the data in the time axis direction of the 138th sampler indicates that the phase of the received radar signal varies due to the respiration of the target 110 .

On the other hand, a ripple appearing in a small size on the data in the time axis direction of almost all samplers represents information about the heartbeat of the target 110. [ The biometric information determination apparatus 100 of the present invention selects samplers included in the region of interest from among a plurality of samplers and performs principal component analysis on data in the time axis direction of the selected samplers, The heart rate information can be measured.

3 is a flowchart illustrating a method of determining biometric information using principal component analysis of an impulse radar signal according to an exemplary embodiment of the present invention.

In step 310, the bio-information determination apparatus 100 may generate a frame set by accumulating a single frame formed by superimposing radar pulses reflected from a target for measuring heartbeats according to a predetermined reception time have. At this time, the generated frame set has a form in which the size of the received radar signal is expressed on the plane formed by the sampled index axis and the time axis. That is, the frame set can be represented by a data structure of a two-dimensional matrix.

In step 320, the biometric information determination apparatus 100 may set the region of interest based on the time series data having a characteristic similar to the heartbeat of the target 110 among the time series data included in the generated frame set. For this purpose, the biological information determination apparatus 100 may first perform a preprocessing process on the time series data, which is a data set in the time axis direction of each sampler in the frame set.

Specifically, the bio-information determination apparatus 100 may use a band-pass filter to extract the heartbeat information of the target 110 by removing the DC component, respiration component, and noise from the time series data of each sampler. Since the heartbeat frequency of a person is distributed in a band of 1 to 3 Hz, the bioinformation determining apparatus 100 filters the time series data of each sampler by using a band-pass filter which selectively passes a signal component composed of frequencies of 1 to 3 Hz, Only the signal components affected by the heartbeat can be left in the set. That is, the low-frequency component or the high-frequency noise component contained in the signal reflected from the stationary background object can be effectively removed through the band-pass filter.

Then, the biometric information determination apparatus 100 sets all values of the data of the frame set subjected to the preprocessing process to a value higher than a specific threshold value, and sets a lower value to "0" You can generate the same binary data. The white point shown in FIG. 4 represents the value of "1" and the black point represents "0". Referring to the time series data of each sampler, in the section from the 150th sampler to the 200th sampler, It can be observed that the phase change pattern appears to be conspicuous.

The biometric information determination apparatus 100 determines a region of the interval from the 150th sampler to the 200th sampler, in which the phase change pattern of the radar signal due to the heartbeat is remarkably more than a predetermined level among the time series data of the frame set converted into the binary data The region of interest 410 may be set.

In step 330, the biometric information determination apparatus 100 performs a principal component analysis on the time series data of the samplers included in the set region of interest, thereby generating one time series data for extracting the heartbeat of the target 110 Can be obtained. Specifically, the bio-information determination apparatus 100 performs principal component analysis on the time series data of the samplers included in the region of interest, and determines the maximum value of the main component (eigenvalue) matching the maximum value The vector can be extracted. The bioinformation determination apparatus 100 can generate one time series data representing time series data of a plurality of samplers included in the region of interest 410 using the extracted principal component vector.

As a result, the biometric information determination apparatus 100 performs dimension reduction by extracting one time series data representative of time series data of a plurality of samplers included in the interest region 410 through principal component analysis, By recovering one time series data obtained as a result of the execution, the heartbeat information of the target 110 such as the thin solid line in FIG. 5 can be extracted.

In operation 340, the biometric information determination apparatus 100 may remove a noise component using the frequency of one time series data obtained. Specifically, the heartbeat waveform of the target 110 extracted by restoring one time-series data obtained through principal component analysis includes a noise component as shown by a thin solid line in FIG. This is because the noise component of the time series data of each sampler is emphasized in the process of performing the principal component analysis and it is necessary to remove the noise component in order to extract the heartbeat information of the accurate target 110.

To this end, the bio-information determination apparatus 100 can first confirm the dominant frequency component by performing frequency conversion on the heartbeat waveform of the extracted target 110 by recovering one time series data obtained through principal component analysis. For example, the biometric information determination apparatus 100 can perform a Fourier transform on the heartbeat waveform of the extracted target 110 to identify the dominant frequency component. At this time, the identified dominant frequency component may be regarded as the actual heartbeat frequency of the target 110, but the present invention uses it only for reference purposes.

Then, the bio-information determination apparatus 100 generates a low-pass filter that cuts off a value obtained by adding about 0.3 to 0.5 Hz to the identified dominant frequency component, By filtering the heartbeat waveform of the extracted target 110, the noise component can be effectively removed. At this time, the process of generating the low-pass filter can be adaptively performed according to the heartbeat waveform of the extracted target 110 as a result of the principal component analysis. The heartbeat waveform of the target 110 from which the noise component is removed is shown by the thick solid line Can appear together.

In operation 350, the biometric information determination apparatus 100 may extract the heartbeat information of the target 110 using one time series data from which noise components are removed. Specifically, since the heartbeat waveform of the target 110 from which the noise component is removed is synchronized with the actual heartbeat of the target 110, the position of each peak can be estimated as the time point of occurrence of the heartbeat. Means a point of time when a heartbeat of the target 110 is generated. Therefore, the bio-information determination apparatus 100 can estimate the time point of occurrence of heartbeat with respect to the target 110 using the peak component, and can estimate the heartbeat frequency of the target 110 through the reciprocal of the time interval between the points of occurrence of the heartbeat Can be calculated.

Meanwhile, the method according to the present invention may be embodied as a program that can be executed by a computer, and may be embodied as various recording media such as a magnetic storage medium, an optical reading medium, and a digital storage medium.

Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or combinations thereof. Implementations may be implemented in a computer program product, such as an information carrier, e.g., a machine readable storage device, such as a computer readable storage medium, for example, for processing by a data processing apparatus, Apparatus (computer readable medium) or as a computer program tangibly embodied in a propagation signal. A computer program, such as the computer program (s) described above, may be written in any form of programming language, including compiled or interpreted languages, and may be stored as a stand-alone program or in a module, component, subroutine, As other units suitable for use in the present invention. A computer program may be deployed to be processed on one computer or multiple computers at one site or distributed across multiple sites and interconnected by a communications network.

Processors suitable for processing a computer program include, by way of example, both general purpose and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer may include one or more mass storage devices for storing data, such as magnetic, magneto-optical disks, or optical disks, or may receive data from them, transmit data to them, . ≪ / RTI > Information carriers suitable for embodying computer program instructions and data include, for example, semiconductor memory devices, for example, magnetic media such as hard disks, floppy disks and magnetic tape, compact disk read only memory A magneto-optical medium such as a floppy disk, an optical disk such as a DVD (Digital Video Disk), a ROM (Read Only Memory), a RAM , Random Access Memory), a flash memory, an EPROM (Erasable Programmable ROM), an EEPROM (Electrically Erasable Programmable ROM), and the like. The processor and memory may be supplemented or included by special purpose logic circuitry.

In addition, the computer-readable medium can be any available media that can be accessed by a computer, and can include both computer storage media and transmission media.

While the specification contains a number of specific implementation details, it should be understood that they are not to be construed as limitations on the scope of any invention or claim, but rather on the description of features that may be specific to a particular embodiment of a particular invention Should be understood. Certain features described herein in the context of separate embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments, either individually or in any suitable subcombination. Further, although the features may operate in a particular combination and may be initially described as so claimed, one or more features from the claimed combination may in some cases be excluded from the combination, Or a variant of a subcombination.

Likewise, although the operations are depicted in the drawings in a particular order, it should be understood that such operations must be performed in that particular order or sequential order shown to achieve the desired result, or that all illustrated operations should be performed. In certain cases, multitasking and parallel processing may be advantageous. Also, the separation of the various device components of the above-described embodiments should not be understood as requiring such separation in all embodiments, and the described program components and devices will generally be integrated together into a single software product or packaged into multiple software products It should be understood.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100: Biometric information determination device
110: Target

Claims (8)

delete Generating a frame set by accumulating a single frame formed by overlapping radar pulses reflected from a target for measuring heartbeat according to a predetermined reception time;
Converting the time series data included in the generated frame set into binary data according to a predetermined criterion to set a region of interest;
Obtaining one time series data for extracting a heartbeat of the target by performing Principal Component Analysis on time series data of samplers included in the set region of interest;
Removing a noise component using the obtained frequency of one time series data; And
Extracting the heartbeat information of the target using one time series data from which the noise component is removed
Lt; / RTI >
Wherein the setting step comprises:
And determining a region of interest based on time-series data having a phase change pattern of a heartbeat-induced phase change of the time-series data of the frame set converted into the binary data. Generating a frame set by accumulating a single frame formed by overlapping radar pulses reflected from a target for measuring heartbeat according to a predetermined reception time;
Converting the time series data included in the generated frame set into binary data according to a predetermined criterion to set a region of interest;
Obtaining one time series data for extracting a heartbeat of the target by performing Principal Component Analysis on time series data of samplers included in the set region of interest;
Removing a noise component using the obtained frequency of one time series data; And
Extracting the heartbeat information of the target using one time series data from which the noise component is removed
Lt; / RTI >
Wherein the removing comprises:
And removing principal components included in the one time series data by using a dominant frequency determined from the obtained one time series data. Generating a frame set by accumulating a single frame formed by overlapping radar pulses reflected from a target for measuring heartbeat according to a predetermined reception time;
Converting the time series data included in the generated frame set into binary data according to a predetermined criterion to set a region of interest;
Obtaining one time series data for extracting a heartbeat of the target by performing Principal Component Analysis on time series data of samplers included in the set region of interest;
Removing a noise component using the obtained frequency of one time series data; And
Extracting the heartbeat information of the target using one time series data from which the noise component is removed
Lt; / RTI >
Wherein the extracting comprises:
And calculating a frequency of a heartbeat for the target using a time interval between peak components of one time series data from which the noise component is removed. delete A processor for processing a single frame formed by superimposing radar pulses reflected from a target for measuring a heartbeat
Lt; / RTI >
The processor comprising:
A frame set is generated by accumulating a single frame formed by overlapping radar pulses reflected from a target for measuring heartbeat according to a predetermined reception time,
The time series data included in the generated frame set is converted into binary data according to a predetermined reference, and the time series data of the frame set converted into the binary data is converted into binary data based on time series data Area,
Acquiring one time series data for extracting a heartbeat of the target by performing Principal Component Analysis on the time series data of the samplers included in the set region of interest,
Removing a noise component using the obtained frequency of one time series data,
And extracting heartbeat information of the target using one time series data from which the noise component is removed. A processor for processing a single frame formed by superimposing radar pulses reflected from a target for measuring a heartbeat
Lt; / RTI >
The processor comprising:
A frame set is generated by accumulating a single frame formed by overlapping radar pulses reflected from a target for measuring heartbeat according to a predetermined reception time,
Converting the time series data included in the generated frame set into binary data according to a predetermined criterion to set a region of interest,
Acquiring one time series data for extracting a heartbeat of the target by performing Principal Component Analysis on the time series data of the samplers included in the set region of interest,
A noise component included in the one time series data is removed using a dominant frequency determined from the obtained one time series data,
And extracting heartbeat information of the target using one time series data from which the noise component is removed. A processor for processing a single frame formed by superimposing radar pulses reflected from a target for measuring a heartbeat
Lt; / RTI >
The processor comprising:
A frame set is generated by accumulating a single frame formed by overlapping radar pulses reflected from a target for measuring heartbeat according to a predetermined reception time,
Converting the time series data included in the generated frame set into binary data according to a predetermined criterion to set a region of interest,
Acquiring one time series data for extracting a heartbeat of the target by performing Principal Component Analysis on the time series data of the samplers included in the set region of interest,
Removing a noise component using the obtained frequency of one time series data,
Wherein a frequency of a heartbeat for the target is calculated using a time interval between peak components of one time series data from which the noise component is removed.

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