KR20190090610A - Differential phase radar bio-signal detection apparatus and method - Google Patents

Abstract

The present invention relates to an apparatus for detecting a differential phase Doppler radar bio-signal and a method thereof. More specifically, when detecting a bio-signal, provided are the apparatus for detecting a differential phase Doppler radar bio-signal which can efficiently remove noise in accordance with the movement of living things and can precisely measure a necessary bio-signal and the method thereof. According to one embodiment of the present invention, the apparatus for detecting a differential phase Doppler radar bio-signal comprises: a transmission unit transmitting a signal to a living thing; a plurality of reception units receiving a signal reflected by the living thing; and a signal processing unit using the signal received by the plurality of reception units to remove a component caused by the movement of the living thing and obtaining a bio-signal.

Description

DIFFERENTIAL PHASE RADAR BIO-SIGNAL DETECTION APPARATUS AND METHOD}

The present invention relates to a differential phase Doppler radar biosignal detection apparatus and method, and more particularly, in detecting a biosignal, a differential capable of efficiently removing noise due to movement of a living body and accurately measuring a required biosignal. A phase Doppler radar biosignal detection apparatus and method.

In recent years, interest in Doppler radar for detecting biosignals has been increasing rapidly. Doppler radars are systems that transmit a single frequency continuous wave to receive a phase modulated continuous wave reflected by a moving object. The phase signal modulated by the continuous wave includes displacement information on the movement of the object over time. The biosignal detector using the Doppler effect can detect a heart rate, respiratory cycle, etc. by receiving a phase modulated signal by physiological movements caused by human heartbeat and respiration. Doppler radars have the advantage of being able to measure bio-signals from a distance without contact and having a simple structure without being affected by the external environment. Therefore, it can be applied to various fields such as patient heart rate monitoring, home health care and vehicle driver heart rate measurement, and researches for this are being actively conducted.

~180

로 제한되는 문제점을 해결하기 위해 extended differentiate and cross multiply (DACM) 알고리즘이 제안되었다.Since the human biological signal is a very small movement, there is a null point problem that cannot be detected by a sinusoidal wave depending on the distance between the Doppler radar and the subject. In order to solve this problem, a Doppler radar structure for outputting I and Q signals having mutually perpendicular phases has been proposed. Doppler radar with such a receiver structure uses the complex signal demodulation method or the arctangent demodulation method to obtain I and Q baseband signals obtained from the receiver. The biosignal can be detected. In addition, the air tangent of the arc tangent function is -180 in the arc tangent demodulation method.

To 180

The extended differentiated and cross multiply (DACM) algorithm is proposed to solve the problem.

Although many technical problems have been solved as researches on the Doppler radar for detecting a biosignal have been conducted, in the case of actually detecting the biosignal using a Doppler radar, even a slight movement (0.5cm ~ 2cm) is larger than the biosignal. There is a serious problem that the signal becomes a noise signal and the signal is distorted. Therefore, it is necessary to remove the noise caused by arbitrary physical movements, not the movement of the heartbeat and breathing, so that accurate bio signals can be detected. Accordingly, methods based on software and hardware for removing any body movement have been studied. However, the software-based method has the disadvantage of removing only a certain pattern of motion or taking a long time to obtain an accurate result. In addition, the proposed hardware-based methods are difficult to implement because of the use of complex radars or additional devices such as cameras, and need to be improved in terms of cost.

Accordingly, it is an object of the present invention to provide an apparatus and method for removing a noise caused by arbitrary body movement and detecting a biosignal using a differential phase signal.

In accordance with an aspect of the present invention, there is provided a differential phase radar biosignal detection apparatus including a transmitter configured to transmit a signal toward a living body, a plurality of receivers receiving a signal reflected from the living body, and the plurality of receivers. It may include a signal processor for removing a component caused by the movement of life using the received signal to obtain a biological signal.

According to an exemplary embodiment of the present disclosure, the apparatus may further include a signal converter converting the signal received from the receiver into a digital signal and transferring the converted signal to the signal processor.

According to an embodiment of the present disclosure, the receiver may be disposed at a symmetrical position with respect to the transmitter.

According to an embodiment of the present invention, four receiving units may be included in up, down, left, and right positions with respect to the transmitter.

According to an embodiment of the present disclosure, the signal processor may obtain a differential phase of signals received by the plurality of receivers to remove noise caused by the movement of a living body and obtain a biosignal.

According to an embodiment of the present invention, the signal processor may convert the signals received by the plurality of receivers into I / Q baseband signals and use them to obtain differential phases.

According to an embodiment of the present invention, the signal processor may obtain a differential phase after removing the dynamic DC offset of the baseband signal.

According to an embodiment of the present invention, the baseband signal from which the dynamic DC offset is removed may be used to obtain an I / Q baseband signal having a polarized differential phase.

According to an embodiment of the present invention, the signal processor may obtain the differential phase by dividing and demodulating the I / Q baseband signal having the differential phase at an angle of polarization by the magnitude of an amplitude noise element.

According to an aspect of the present invention, there is provided a differential phase radar biosignal detection method, comprising: transmitting a signal to a living body, receiving a signal reflected from the living body at a plurality of positions; And removing the components caused by the movement of life using the plurality of signals received at the plurality of positions, and obtaining a biosignal.

According to an embodiment of the present disclosure, the signal receiving step may be disposed at a position symmetrical with respect to the transmitter in the plurality of receivers.

According to an embodiment of the present invention, four receiving units may be included in up, down, left, and right positions with respect to the transmitter.

According to an embodiment of the present disclosure, the obtaining of the biosignal may obtain a differential phase of the signals received by the plurality of receivers to remove noise caused by the movement of the living body and acquire the biosignal.

According to an embodiment of the present disclosure, the obtaining of the biosignal may include converting signals received by the plurality of receivers into I / Q baseband signals to obtain a differential phase.

According to an embodiment of the present disclosure, the obtaining of the biosignal may further include obtaining a differential phase after removing the dynamic DC offset of the baseband signal.

According to an embodiment of the present disclosure, the obtaining of the biosignal may further include calculating and obtaining an I / Q baseband signal having a polarized differential phase using the baseband signal from which the dynamic DC offset is removed. .

According to an embodiment of the present disclosure, the obtaining of the biosignal may further include obtaining a differential phase of dividing and demodulating an I / Q baseband signal having the differential phase at an angle of declination by an amplitude noise component.

According to the present invention, it is possible to remove the body movement of the living body and to accurately measure the bio-signals.

In addition, it is possible to provide a technology that can more accurately detect the measured bio-signals by removing the movement of life and measuring the bio-signals, and by catching the signal modulation due to noise generated in addition to the movement than conventional techniques.

In addition, the present invention can be easily applied with a simple design change without introducing a new device into the existing biosignal detection apparatus and method.

1 is an example of a Doppler radar biosignal detection apparatus.
2 is an example of an apparatus for detecting a Doppler radar biosignal for removing life movement.
3 is a block diagram of an apparatus for detecting a Doppler radar biosignal according to an embodiment of the present invention.
4 is a block diagram of an apparatus for detecting a Doppler radar biosignal according to an embodiment of the present invention.
5 is an example of a dynamic DC offset cancellation method of a baseband signal according to an embodiment of the present invention.
6 is an example of a method of obtaining a differential phase by using a baseband signal according to an embodiment of the present invention.
7 is an example of arrangement of a transceiver of a Doppler radar biosignal detecting apparatus according to an embodiment of the present invention.
8 is a flowchart illustrating a Doppler radar biosignal detection method according to an embodiment of the present invention.

Hereinafter, an apparatus and method for detecting a differential phase Doppler radar biosignal according to the present invention will be described in detail with reference to the accompanying drawings. The embodiments are provided so that those skilled in the art can easily understand the technical spirit of the present invention, and thus the present invention is not limited thereto. In addition, the matters described in the attached drawings may be different from those actually implemented by the schematic drawings to easily describe the embodiments of the present invention.

In addition, each component expressed below is only an example for implementing this invention. Thus, in other implementations of the present invention, other components may be used without departing from the spirit and scope of the present invention.

In addition, each component may be implemented solely by hardware or software configuration, but may be implemented by a combination of various hardware and software configurations performing the same function. In addition, two or more components may be implemented together by one hardware or software.

Also, the expression " comprising " is intended to merely denote that such elements are present as an expression of " open ", and should not be understood to exclude additional elements.

1 is an example of a Doppler radar biosignal detection apparatus.

Referring to FIG. 1, a conventional Doppler radar for detecting a biosignal sends a signal generated by an oscillator to a creature through a transmitter TX, and then receives a signal reflected from the creature and returns from the receiver RX. The biosignal can be detected by receiving. A conventional Doppler radar for detecting a biosignal is composed of one receiver and one transmitter and uses a direct conversion structure to simplify the structure. To solve the null point problem, we take a structure that demodulates the I / Q quadrature signal. The radar transmitter propagates a single frequency continuous wave and receives the phase modulated signal at the receiver to detect heartbeat and respiration signals.

However, when a living body is accompanied by body motion without stopping the living body, the Doppler radar for detecting the biological signal includes both the biological signal and the body motion noise signal in the demodulated phase signal. Therefore, the demodulated phase signal may be expressed as a linear sum of the biosignal and the body motion signal. In general, since the body motion signal is larger in magnitude than the biosignal, the accurate biosignal cannot be detected. In the case where the structure is applied to the detection of the actual bio-signal using such a structure, there is a problem that a detection error is likely to occur since the subject is not stopped without any movement.

2 is an example of an apparatus for detecting a Doppler radar biosignal for removing life movement.

Referring to FIG. 2, a conventional Doppler radar signal detecting apparatus for removing living body movements has been proposed in which a Doppler radar structure using two songs and receivers is used to remove arbitrary body movements. 1 is a method of removing arbitrary body movements by using two phases of a Doppler radar song and a receiver as shown in FIG. In order to demodulate the phase, a complex signal demodulation method is used, and arbitrary body movements are eliminated by multiplying the signals detected from the front and the rear. Such a demodulation method does not take into account the change in the DC offset and the AC amplitude included in the baseband signal, so that there is a high possibility of detection error for a large motion. In addition, the bidirectional radar arrangement as shown in FIG. 2 has a disadvantage in that it is difficult to apply to an actual application and the hardware configuration is very complicated compared to the conventional Doppler radar sensor.

3 and 4 are block diagrams of a Doppler radar biosignal detection apparatus according to an embodiment of the present invention.

3 and 4, the Doppler radar biosignal detecting apparatus according to an exemplary embodiment may include a transceiver 310, a signal processor 320, and a signal converter 330.

The transceiver 310 may include a transmitter 311 for transmitting a signal toward the creature 301 and a receiver 312 for receiving a signal reflected from the creature 301. The receiver 312 may be included in plural to receive signals individually at different locations. The signal received by the receiver 312 may include a biosignal. The biosignal may include a biosignal such as a heartbeat, respiration, and pulse. The biological signal may include vibration by voice.

The transmitter 311 may transmit a single frequency continuous wave to the living body 301. The transmitter 311 may include an electromagnetic wave, an electromagnetic wave, and the like, and may include an RF signal, an optical signal, and an ultrasonic wave, and may transmit information without being limited thereto. It can contain all kinds of signals. The signal transmitted from the transmitter 311 to the creature 301 may be reflected by the creature 301 and received by the receiver 312, and the reflected signal may be related to the biosignal of the creature 301. May contain information. The signal may be reflected by the body of the living body 301 and phase-modulated by the biological signal of the living body 301 to include information about the biological signal.

The receiver 312 may receive a signal including information about the biosignal. The receiver 312 may be included in plurality. The plurality of receivers 312 may be disposed at a plurality of positions, respectively, to receive a signal. The receiver 312 may be disposed or positioned in a symmetrical form with respect to the transmitter 311. The receiving unit 312 may be individually disposed or positioned up, down, left, and right about the transmitter 311. The receiver 312 may be arranged in a plurality of circular forms around the transmitter 311. The receiver 312 may receive a signal reflected from the living body 301 and then convert or drop it into a baseband signal. The receiver 312 may receive a signal reflected from the living body 301 and convert the signal to an I / Q baseband signal having a quadrature phase.

만큼 위상 변조된 신호로, 여기서는 두 개의 수신부(312)를 사용하는 것으로 가정한다. 두 수신부(312)에서 출력된 I/Q 기저대역 신호는 수학식 4와 같이 표현 할 수 있다.The receiver 312 is an I / Q baseband signal

As a phase modulated signal, it is assumed here that two receivers 312 are used. The I / Q baseband signals output from the two receivers 312 may be expressed by Equation 4.

&Quot; (4) "

와

는 교류 신호의 진폭을 나타내며

와

는 기저대역 신호의 직류 오프셋 전압을 나타낸다. 여기서 직류 오프셋 전압은 피 측정자의 주변물체와 피 측정자의 위치 그리고 수신부(312) 회로 내에서 축적된 직류 오프셋이 모두 포함되어 나타난다. 위 식의 삼각함수에 포함된

는 송신하는 단일주파수 지속파의 파장,

는 송신 경로에 따른 residual phase offset을 의미한다.In the above equation

Wow

Represents the amplitude of the AC signal

Wow

Denotes the DC offset voltage of the baseband signal. In this case, the DC offset voltage includes both the object around the subject, the position of the subject, and the DC offset accumulated in the receiver 312 circuit. Included in the trigonometric function

Is the wavelength of a single-frequency continuous wave

Denotes a residual phase offset according to a transmission path.

The signal converter 330 may convert the signal received by the receiver 312 into an analog signal and a digital signal. The signal converter 330 may provide the converted signal to the signal processor 320. The signal converter 330 may convert a signal received by the receiver 312 into a signal having an advantageous shape for processing by the signal processor 320.

The signal processor 320 may detect a biosignal by acquiring a differential phase of signals received by the plurality of receivers 312.

, 호흡신호

그리고 임의의 공통된 신체 움직임 신호

의 선형 합으로 나타낼 수 있다. 따라서, i 번째 수신부(312)에서 검출된 위상

는

로 나타낼 수 있다. 심장박동신호

와 호흡신호

는 주기적인 움직임 이므로 간단히 사인파의 형태로 나타낼 수 있으므로 첫번째 수신부(312)와 두번째 수신부(312)에서 검출되는 위상은 각각 수학식 1 및 수학식 2와 같이 근사적으로 표현 할 수 있다.According to an embodiment of the present invention, the signal processor 320, the phase information included in the received signal when detecting the biological signal is a heartbeat signal

Breathing signal

And any common body movement signals

It can be expressed as a linear sum of. Thus, the phase detected by the i-th receiver 312

The

. Heart rate signal

And breathing signals

Since is a periodic movement, it can be simply expressed in the form of a sine wave, and thus the phases detected by the first receiver 312 and the second receiver 312 can be approximately expressed as Equation 1 and Equation 2, respectively.

[Equation 1]

&Quot; (2) "

과

은 진폭,

과

는 주파수, 그리고

와

는 각각 호흡과 심장박동에 대한 초기 위상을 의미한다. 또,

,

과

,

는 각각 두 수신부(312)에서 검출된 호흡과 심장박동에 의한 움직임의 진폭과 위상 차이를 말한다. 위의 두 식을 이용하여 차동위상

을 수학식 3과 같이 표현 할 수 있다.here,

and

Is the amplitude,

and

Is the frequency, and

Wow

Are the initial phases of breathing and heart rate, respectively. In addition,

,

and

,

Denotes the amplitude and phase difference of movement due to respiration and heartbeat detected by the two receivers 312, respectively. Differential phase using the above two equations

Can be expressed as in Equation 3.

&Quot; (3) "

,

과

,

에 의해 결정된다. 따라서, 두 수신부(312)에서 검출된 생체 신호의 진폭과 위상 차이가 클수록 위상 차이 신호에서 더 큰 크기의 생체 신호로 나타난다. 반면, 두 수신부(312)에서 공통적으로 검출된 신호는 상쇄 되므로 이를 이용하면 공통된 신체 움직임을 상쇄하는 동시에 생체 신호를 검출 할 수 있게 된다.As shown in Equation 3, the differential phase signal includes frequency information of respiration and heartbeat. If you convert a time domain signal into a frequency domain signal, the magnitude of the frequency component of the biological signal

,

and

,

. Therefore, the larger the amplitude and phase difference of the biological signals detected by the two receivers 312, the larger the biological signal appears in the phase difference signal. On the other hand, since the signals commonly detected by the two receivers 312 are canceled, the signals can be detected at the same time by canceling the common body movement.

5 is an example of a dynamic DC offset cancellation method of a baseband signal according to an embodiment of the present invention.

만큼 위상 변조된 신호로, 본 발명의 일 실시 예에서는 두 개의 수신부(312)를 사용하는 것으로 가정한다. 두 수신부(312)에서 출력된 I/Q 기저대역 신호는 수학식 4와 같이 표현 할 수 있다.Referring to FIG. 5 (a), after the transmission signal is reflected on the body, the signal received by the receiver 312 is converted into an I / Q baseband signal. I / Q baseband signals

As a phase-modulated signal, it is assumed that two receivers 312 are used in an embodiment of the present invention. The I / Q baseband signals output from the two receivers 312 may be expressed by Equation 4.

&Quot; (4) "

와

는 교류 신호의 진폭을 나타내며

와

는 기저대역 신호의 직류 오프셋 전압을 나타낸다. 상기 직류 오프셋 전압은 피 측정자의 주변물체와 피 측정자의 위치 그리고 수신부(312) 회로 내에서 축적된 직류 오프셋이 모두 포함되어 나타날 수 있다. 위 식의 삼각함수에 포함된

는 송신하는 단일주파수 지속파의 파장,

는 송신 경로에 따른 잔류 위상 오프셋(residual phase offset)을 의미한다.here,

Wow

Represents the amplitude of the AC signal

Wow

Denotes the DC offset voltage of the baseband signal. The DC offset voltage may include both a peripheral object of the subject, the position of the subject, and a DC offset accumulated in the receiver 312 circuit. Included in the trigonometric function

Is the wavelength of a single-frequency continuous wave

Denotes a residual phase offset along the transmission path.

와

그리고

와

는 일정한 값으로 근사할 수 있다. 하지만, 작은 움직임뿐 만 아니라 임의의 신체 움직임과 같은 큰 움직임이 포함된 경우

와

그리고

와

는 배경 산란(background scattering)의 변화와 움직임에 의한 피 측정자의 위치 변화로 인해 시간에 따라 변하는 변수가 된다. 따라서, 기저대역 신호에 포함된 위상정보를 정확히 검출하기 위해서는 시간에 따라 변하는 교류 신호의 진폭과 직류 오프셋에 대한 측정(calibration)이 필요하다. 본 발명의 일 실시 예에 따르면 기저대역 신호의 I, Q 신호간의 교류 신호 진폭에 대한 차이는 Gram-Schmidt procedure 또는 digital-IF 구조의 수신부(312)를 이용하여 측정(calibration) 할 수 있으며 여기서는 I, Q 신호간의 교류 신호 진폭에 대한 차이는 무시한다.The Doppler radar biosignal detection device detects motion smaller than the wavelength of the transmitted signal.

Wow

And

Wow

Can be approximated to a constant value. However, if you include not only small movements but also large movements such as arbitrary body movements

Wow

And

Wow

Is a variable that changes over time due to changes in background scattering and changes in the position of the subject due to movement. Therefore, in order to accurately detect the phase information included in the baseband signal, it is necessary to measure the amplitude and the DC offset of the AC signal that changes over time. According to an embodiment of the present invention, the difference in the AC signal amplitude between the I and Q signals of the baseband signal may be measured using the Gram-Schmidt procedure or the receiver 312 of the digital-IF structure, where I However, the difference in the amplitude of the AC signal between the Q signals is ignored.

를 복조하기 전에 기저대역 신호에 포함된 직류 오프셋을 제거해 기저대역 신호를 만들 수 있다. 직류 오프셋은 기저대역 신호의 I/Q trajectory에서 원의 중심으로 생각할 수 있다. 상기 신호처리부(320)는 시간에 따라 변하는 직류 오프셋은 원의 중심을 동적으로 추적해 얻을 수 있다. 여기서는 단위 시간을 나누어 수신된 원들의 중심을 계산한다. 샘플링 된 기저대역 I/Q 신호들 전체를 (

[1],

[1]), (

[2],

[2])

(

[N],

[N]) 이라고 할 때, 적당한 단위 길이

으로 샘플링 데이터를 나누어 단위 시간 원으로 정의한다. 이때, 단위 시간 원의 직류 오프셋과 교류 진폭은 일정하다고 근사할 수 있다. 단위 시간 원의 중심은 수학식 5와 같은 최적화 함수를 계산하여 얻을 수 있다.5 (b), the signal processor 320 is a differential phase signal

Before demodulating, the baseband signal can be removed by removing the DC offset included in the baseband signal. The DC offset can be thought of as the center of the circle in the I / Q trajectory of the baseband signal. The signal processor 320 may obtain a DC offset that changes over time by dynamically tracking the center of the circle. Here, the unit time is divided to calculate the center of the received circles. The entire sampled baseband I / Q signals

[1] ,

[One]), (

[2] ,

[2])

(

[N],

[N]), the proper unit length

By dividing the sampling data, define the unit time circle. At this time, it can be approximated that the DC offset and the AC amplitude of the unit time circle are constant. The center of the unit time circle can be obtained by calculating an optimization function such as Equation 5.

&Quot; (5) "

에 의해 결정된다. 상기 신호처리부(320)에서 기저대역 신호에서 직류 오프셋이 제거 되고 나면 도 5 (b)와 같이 원들의 중심이 I/Q 직교평면에서 원점에 위치하게 된다. 제안된 차동위상을 수신하는 도플러 레이다에서 위상 차이는 직류 오프셋이 정확히 제거 된 후 얻을 수 있으며 직류 오프셋이 남아있게 되면 차동위상 신호를 계산하는데 오류가 발생하게 될 수 있다.Where the mth dc offset value is

. After the DC offset is removed from the baseband signal by the signal processor 320, the centers of the circles are located at the origin in the I / Q orthogonal plane as shown in FIG. In the Doppler radar receiving the proposed differential phase, the phase difference can be obtained after the DC offset is correctly removed. If the DC offset remains, an error in calculating the differential phase signal may occur.

6 is an example of a method of obtaining a differential phase by using a baseband signal according to an embodiment of the present invention.

Referring to FIG. 6, the signal processor 320 calculates a quadrature phase signal having a phase difference between two received signals at a polarization angle before a phase difference demodulation process. The I / Q baseband signal received after calibrating the dynamic DC offset may be calculated by Equation 6 as shown in FIG.

&Quot; (6) "

는 위상 차이 복조과정에서 영향을 주지 않는 상수이므로 무시할 수 있다. 따라서, 도 6 (b)의 차동 위상 신호를 편각으로 갖는 직각위상 신호

는 위의 I/Q 기저대역 신호를 이용하여 수학식 7과 같이 계산될 수 있다.Where residual phase

Is a constant that does not affect phase difference demodulation and can be ignored. Therefore, the quadrature phase signal having the differential phase signal of FIG.

May be calculated as shown in Equation 7 using the I / Q baseband signal.

[Equation 7]

.

.

는 여전히 교류 진폭

을 포함 하고 있지만, 이는 제안된 위상 차이 복조 과정에서 정확한 차동위상 정보를 얻기 위해 상쇄 될 수 있다.Equation 7 can be obtained by using a simple trigonometric function. Quadrature Phase Signal with Differential Phase

Is still alternating amplitude

However, this can be canceled to obtain accurate differential phase information in the proposed phase difference demodulation process.

The signal processor 320 performs a process of demodulating the differential phase after calculating a quadrature phase signal having the differential phase as a polarization angle. The signal processor 320 may demodulate a signal using a complex signal demodulation (CSD) method and an amplitude-compensated complex signal demodulation (ACCSD) method that improves CSD. ACCSD method can extract only accurate phase information by mitigating the influence of AC amplitude of baseband signal.

CSD may be demodulated by applying Equation 8 to the quadrature signal having the differential phase at a polar angle.

[Equation 8]

.

.

는 잡음신호이다. 상기 CSD로 복조하면 복조된 신호에 차동위상이 아닌 잡음 신호

가 여전히 포함될 수 있다. 상기 복조된 신호를 FFT 처리 할 경우 그 결과는 위상차이 신호인

와 교류 진폭 잡음 요소인

의 convolution 형태로 나타나게 된다. 따라서 온전한 위상차이 정보를 얻기 위해서는 진폭 잡음 신호가 제거 되어야 하며 이는 ACCSD 방법으로,

로 나눈 수학식 9를 계산해 수행될 수 있다. here,

Is a noise signal. When demodulating with the CSD, a noise signal other than the differential phase is applied to the demodulated signal.

May still be included. In case of FFT processing the demodulated signal, the result is phase difference signal.

And AC amplitude noise factor

It appears as a convolution of. Therefore, in order to obtain the full phase difference information, the amplitude noise signal must be removed. This is the ACCSD method.

Equation 9 divided by may be performed.

 &Quot; (9) "

The differential phase signal demodulated using the ACCSD method is free from AC amplitude noise caused by large body movements. As can be seen from Equation 9, the AC amplitude can be obtained by calculating the baseband signal from which the DC offset is removed.

7 is an example of arrangement of a transceiver of a Doppler radar biosignal detecting apparatus according to an embodiment of the present invention.

Referring to FIG. 7, in the Doppler radar biosignal detecting apparatus according to an exemplary embodiment, a plurality of receivers may be disposed around the transmitter 311.

라 하면, 6개의 차동위상 신호로 더욱 복잡한 형태의 신체 움직임을 상쇄할 수 있다. 생명체(301)가 앞-뒤, 위-아래, 그리고 좌-우로 움직이는 경우 6개의 차동위상 모두 움직임을 상쇄 할 수 있으며 상기 생명체(301)가 양 옆으로 비트는 움직임은

, 구부리는 움직임은

에 의해 상쇄 할 수 있다. 본 발명의 일 실시 예에 따른 도플러 레이더 생체신호 검출 장치 상기한 방법을 이용해 복잡한 신체 움직임을 제거할 수 있을 뿐만 아니라 높은 신호 대 잡음비를 갖는 검출이 가능하다. As shown in FIG. 7, when four signals are received by the four receivers 312, the four receivers 312 may detect differential phases with the other receivers 312. In Figure 7, the differential phase between the receiver 312

6 differential phase signals can compensate for more complex body movements. When the creature 301 moves forward-backward, up-down, and left-right, all six differential phases can cancel out the movements.

Bending movement

Can be offset by Doppler radar biosignal detection apparatus according to an embodiment of the present invention not only can remove complex body movements using the method described above, but also has a high signal-to-noise ratio detection.

의 공통된 신호를 추출해 내기 위해 차동위상 신호끼리의 교차연관(cross-correlation)하는 방법을 사용한다. 즉, 연산자

를 교차연관(cross-correlation)이라고 하면 아래와 같은 수학식 10을 통해 차동위상 신호 간의 공통신호를 찾을 수 있다.Demodulated Differential Phase Signal Using Differential Phase Demodulation Method

The cross-correlation of differential phase signals is used to extract the common signal of. That is, operator

When cross-correlation is referred to as cross-correlation, a common signal between differential phase signals can be found through Equation 10 shown below.

&Quot; (10) "

=

=

는 복수의 수신부(312)를 이용해 획득한 차동위상 신호이다. 상기 복수의 차동위상 신호를 전부를 사용하지 않고 그 중 몇 개만을 사용하여 신호처리 시간을 줄일 수 있으며, 교차연관(cross-correlation)을 수학식 11과 같이 주파수 도메인에서 진행할 경우 신호처리 시간을 단축 할 수 있다.here,

Is a differential phase signal obtained using the plurality of receivers 312. Signal processing time can be reduced by using only a few of the plurality of differential phase signals, and the signal processing time is shortened when cross-correlation is performed in the frequency domain as shown in Equation (11). can do.

&Quot; (11) "

=

=

As shown in Equation 11, after performing fast Fourier transform on each of the differential phase signals, cross-correlation calculation may be performed using their conjugate products.

The Doppler radar biosignal detection apparatus according to an exemplary embodiment of the present invention does not use the antennas of the receiver 312 as the same polarization in a differential phase Doppler radar including a plurality of receivers 312 or two receivers 312. It is possible to configure the system to have different polarizations. Since the magnitude and phase of the received biosignal varies depending on the antenna polarization, the antenna of the receiver 312 receiving the heartbeat signal at the shortest distance is configured by co-polarization with the transmitter antenna and the antenna of the other receiver 312 is Using the wrong angle antenna polarization can increase the differential phase effect on the biosignal and cancel the large common body motion signal.

8 is a flowchart illustrating a Doppler radar biosignal detection method according to an embodiment of the present invention.

Referring to FIG. 8, the method of detecting a Doppler radar biosignal according to an embodiment of the present disclosure may include a step (S801) of a transmitter transmitting a signal to a living organism.

In operation S801, the single frequency sustain wave may be transmitted to the living organism 301. In operation S801, the signal transmitted from the transmitter 311 to the living organism 301 may include an RF signal, an optical signal, and an ultrasonic wave, but may include all kinds of signals capable of transferring information.

The method of detecting a Doppler radar biosignal according to an embodiment of the present invention may include receiving a signal reflected from the living body at a plurality of locations (S802).

In operation S802, a signal transmitted from the transmitter 311 to the living organism 301 may be reflected by the living creature 301 and received by the receiving unit 312, and the reflected signal may be a living body of the living creature 301. It may include information about the signal. The signal may be reflected by the body of the living body 301 and phase-modulated by the biological signal of the living body 301 to include information about the biological signal.

In operation S802, the receiver 312 may receive a signal including information about the biosignal. The receiver 312 may be included in plurality. The plurality of receivers 312 may be disposed at a plurality of positions, respectively, to receive a signal. The receiver 312 may be disposed or positioned in a symmetrical form with respect to the transmitter 311. The receiving unit 312 may be individually disposed or positioned up, down, left, and right about the transmitter 311. The receiver 312 may be arranged in a plurality of circular forms around the transmitter 311. The receiver 312 may receive a signal reflected from the living body 301 and then convert or drop it into a baseband signal. The receiver 312 may receive a signal reflected from the living body 301 and convert the signal to an I / Q baseband signal having a quadrature phase.

만큼 위상 변조된 신호로, 여기서는 두 개의 수신부(312)를 사용하는 것으로 가정한다. 두 수신부(312)에서 출력된 I/Q 기저대역 신호는 수학식 4를 계산해 획득할 수 있다.In step S802, the receiver 312 is an I / Q baseband signal.

As a phase modulated signal, it is assumed here that two receivers 312 are used. The I / Q baseband signals output from the two receivers 312 may be obtained by calculating Equation 4.

만큼 위상 변조된 신호로, 본 발명의 일 실시 예에서는 두 개의 수신부(312)를 사용하는 것으로 가정한다. 두 수신부(312)에서 출력된 I/Q 기저대역 신호는 수학식 4를 계산해 얻을 수 있다.In operation S802, the signal received by the receiver 312 is converted into an I / Q baseband signal. I / Q baseband signals

As a phase-modulated signal, it is assumed that two receivers 312 are used in an embodiment of the present invention. The I / Q baseband signals output from the two receivers 312 can be obtained by calculating Equation 4.

Doppler radar biosignal detection method according to an embodiment of the present invention may include the step of removing the components caused by the movement of life using a plurality of signals received at the plurality of locations and obtaining a biosignal (S803). .

In operation S803, the signal processor 320 may acquire a differential phase of signals received by the plurality of receivers 312 to detect a biosignal.

, 호흡신호

그리고 임의의 신체 움직임 신호

의 선형 합으로 나타낼 수 있다. 따라서, i 번째 수신부(312)에서 검출된 위상

는

로 나타낼 수 있다. 심장박동신호

와 호흡신호

는 주기적인 움직임 이므로 간단히 사인파의 형태로 나타낼 수 있으므로 첫번째 수신부(312)와 두번째 수신부(312)에서 검출되는 위상의 차동위상

을 상기 수학식 3을 계산해 획득할 수 있다.According to an embodiment of the present invention at step S803, the signal processing unit 320 detects a biosignal, and the phase information included in the received signal is a heartbeat signal.

Breathing signal

And random body movement signals

It can be expressed as a linear sum of. Thus, the phase detected by the i-th receiver 312

The

. Heart rate signal

And breathing signals

Since is a cyclic movement, it can be simply expressed in the form of a sine wave, so the differential phase of the phase detected by the first receiver 312 and the second receiver 312

May be obtained by calculating Equation 3 above.

In step S803, the difference in the AC signal amplitude between the I and Q signals of the baseband signal may be measured by using the Gram-Schmidt procedure or the receiver 312 of the digital-IF structure. Ignore the difference in signal amplitude.

를 복조하기 전에 기저대역 신호에 포함된 직류 오프셋을 제거해 기저대역 신호를 만들 수 있다. 직류 오프셋은 기저대역 신호의 I/Q trajectory에서 원의 중심으로 생각할 수 있다. 상기 신호처리부(320)는 시간에 따라 변하는 직류 오프셋은 원의 중심을 동적으로 추적해 얻을 수 있다. 여기서는 단위 시간을 나누어 수신된 원들의 중심을 계산한다. 샘플링 된 기저대역 I/Q 신호들 전체를 (

[1],

[1]), (

[2],

[2])

(

[N],

[N]) 이라고 할 때, 적당한 단위 길이

으로 샘플링 데이터를 나누어 단위 시간 원으로 정의한다. 이때, 단위 시간 원의 직류 오프셋과 교류 진폭은 일정하다고 근사할 수 있다. 단위 시간 원의 중심은 상기 수학식 5와 같은 최적화 함수를 계산하여 얻을 수 있다.In step S803, the signal processor 320 is a differential phase signal.

Before demodulating, the baseband signal can be removed by removing the DC offset included in the baseband signal. The DC offset can be thought of as the center of the circle in the I / Q trajectory of the baseband signal. The signal processor 320 may obtain a DC offset that changes over time by dynamically tracking the center of the circle. Here, the unit time is divided to calculate the center of the received circles. The entire sampled baseband I / Q signals

[1] ,

[One]), (

[2] ,

[2])

(

[N],

[N]), the proper unit length

By dividing the sampling data, define the unit time circle. At this time, it can be approximated that the DC offset and the AC amplitude of the unit time circle are constant. The center of the unit time circle can be obtained by calculating an optimization function as shown in Equation 5 above.

After the DC offset is removed from the baseband signal by the signal processor 320 in step S803, the centers of the circles are located at the origin in the I / Q orthogonal plane as shown in FIG. In the Doppler radar receiving the proposed differential phase, the phase difference can be obtained after the DC offset is correctly removed. If the DC offset remains, an error in calculating the differential phase signal may occur.

는 위의 I/Q 기저대역 신호를 이용하여 수학식 7을 계산해 얻을 수 있다.In step S803, the signal processor 320 calculates a quadrature phase signal having a phase difference between two received signals at a polar angle before the phase difference demodulation process. The received I / Q baseband signal after calibrating the dynamic DC offset may be obtained by calculating Equation 6 above. Quadrature signal having polarization of the differential phase signal

Equation 7 can be obtained by using the above I / Q baseband signal.

는 여전히 교류 진폭

을 포함 하고 있지만, 이는 본 발명의 일 실시 예에 따른 위상 차이 복조 과정에서 정확한 차동위상 정보를 얻기 위해 상쇄 될 수 있다.Equation 7 in step S803 can be obtained using a simple trigonometric function. Quadrature Phase Signal with Differential Phase

Is still alternating amplitude

However, this may be canceled to obtain accurate differential phase information in the phase difference demodulation process according to an embodiment of the present invention.

In step S803, the signal processing unit 320 calculates a quadrature phase signal having the differential phase at a polarization angle, and then proceeds to demodulate the differential phase. The signal processor 320 may demodulate a signal using a complex signal demodulation (CSD) method and an amplitude-compensated complex signal demodulation (ACCSD) method that improves CSD. ACCSD method can extract only accurate phase information by mitigating the influence of AC amplitude of baseband signal.

In operation S803, the CSD may be demodulated by applying the equation (8) to the quadrature signal having the differential phase at a polarization angle.

로 나눈 상기 수학식 9를 계산해 수행될 수 있다. In order to obtain the complete phase difference information in step S803, the amplitude noise signal should be removed, which is the ACCSD method.

It can be performed by calculating Equation 9 divided by.

The differential phase signal demodulated using the ACCSD method is free from AC amplitude noise caused by large body movements. As can be seen from Equation 9, the AC amplitude can be obtained by calculating the baseband signal from which the DC offset is removed.

In the method of detecting a Doppler radar biosignal according to an embodiment of the present invention, the signal converter 330 converts a signal received by the receiver 312 into an analog signal as a digital signal and a digital signal into an analog signal ( Not shown). The signal converter 330 may provide the converted signal to the signal processor 320. The signal converter 330 may convert a signal received by the receiver 312 into a signal having an advantageous shape for processing by the signal processor 320.

The present invention has been described with reference to the preferred embodiments. Those skilled in the art will understand that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (17)

A transmitter for transmitting a signal toward a living organism;
A plurality of receivers for receiving a signal reflected from the living body; And
And a signal processor which removes a component caused by the movement of the living body from the plurality of signals received by the plurality of receivers and obtains a biosignal.
The method of claim 1,
And a signal converter converting the signal received from the receiver into a digital signal and transferring the converted signal to the signal processor.
The method of claim 1,
The plurality of receivers,
And a differential phase radar biosignal detection device disposed at a symmetrical position with respect to the transmitter.
The method of claim 3,
The receiver may further comprise:
The apparatus for detecting a differential phase radar biosignal including four up, down, left and right positions with respect to the transmitter.
The method of claim 1,
The signal processing unit,
And a differential phase radar biosignal detection device which obtains a biosignal by removing noise caused by movement of a living being by obtaining a differential phase of any two signals among a plurality of signals received by the plurality of receivers.
The method of claim 5,
The signal processing unit,
And a differential phase radar biosignal detection device for converting signals received by the plurality of receivers into I / Q baseband signals to obtain a differential phase.
The method according to claim 6,
The signal processing unit,
And a differential phase radar biosignal detection device that obtains a differential phase after removing the dynamic DC offset of the baseband signal.
The method of claim 7, wherein
And a differential phase radar biosignal detection device for calculating an I / Q baseband signal having a polarized differential phase by using the baseband signal from which the dynamic DC offset is removed.
9. The method of claim 8,
The signal processing unit,
And a differential phase radar biosignal detection device for obtaining a differential phase that divides and demodulates the I / Q baseband signal having the differential phase at an angle of declination.
Transmitting a signal to a living unit by a transmitter;
Receiving, by a plurality of receivers, a plurality of signals reflected from the creature at a plurality of positions; And
And removing a component caused by the movement of the living body and acquiring a biological signal by using the plurality of signals received at the plurality of positions.
The method of claim 10,
The signal receiving step includes:
And a plurality of receivers arranged at symmetrical positions with respect to the transmitter.
12. The method of claim 11,
The receiver may further comprise:
4. A method of detecting a differential phase radar biosignal including four up, down, left, and right positions about the transmitter.
The method of claim 10,
The biosignal obtaining step,
Differential phase radar bio-signal detection method of obtaining a bio-signal by removing the noise caused by the movement of life by obtaining the differential phase of any two signals of the plurality of signals received by the plurality of receivers.
The method of claim 13,
The biosignal obtaining step,
And converting the signals received by the plurality of receivers into I / Q baseband signals to obtain differential phases.
15. The method of claim 14,
The biosignal obtaining step,
And obtaining a differential phase after removing the dynamic DC offset of the baseband signal.
16. The method of claim 15,
The biosignal obtaining step,
And calculating an I / Q baseband signal having a polarized differential phase by using the baseband signal from which the dynamic DC offset is removed.
17. The method of claim 16,
The biosignal obtaining step,
And obtaining a differential phase for dividing and demodulating the I / Q baseband signal having the differential phase at an angle of declination by the magnitude of an amplitude noise element.

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