JP7428605B2 - Respiratory heart rate measuring device and respiratory heart rate measuring program - Google Patents

Description

The present disclosure relates to a technique for measuring a subject's breathing rate and heart rate using radar.

A technique for measuring a subject's breathing rate and heart rate using a radar is disclosed in Patent Document 1 and the like. In Patent Document 1, etc., the subject is detected by detecting the time change in the position of the body surface of the subject resulting from the subject's breathing and heartbeat as the time change in the amplitude or phase of the radar signal reflected from the subject. The breathing rate and heart rate of the subject can be measured without contact with the subject.

Japanese Patent Application Publication No. 2019-013479

FIG. 1 shows the respiratory heart rate measurement process of Patent Document 1. First, by applying a bandpass filter having a pass band corresponding to the general breathing rate to the radar signal, it is possible to extract the radar signal component having the frequency _fB1 and the large power P from the radar signal. The breathing rate of the patient can be measured. Next, by applying a bandpass filter having a pass band corresponding to a general heart rate to the radar signal, it is possible to extract a radar signal component having a frequency _fH1 and a small power P from the radar signal. The heart rate of the specimen can be measured.

Here, the radar signal component originating from the subject's respiration includes not only a radar signal component having a fundamental frequency f _B1 and a large power P, but also harmonic frequencies f _B2 and f _B3 resulting from a non-sinusoidal signal or non-linear distortion. (further harmonic frequencies have been omitted). However, while the radar signal component with fundamental frequency f _B1 is taken into account, the radar signal components with harmonic frequencies f _B2 , f _B3 are not taken into account. As the radar signal component derived from the heartbeat of the subject, not only the radar signal component with a small power P having the fundamental frequency f _H1 but also harmonic frequencies f _H2 and f _H3 resulting from a non-sinusoidal signal or non-linear distortion are used. There is a radar signal component with However, while the radar signal component with the fundamental frequency f _H1 is taken into account, the radar signal components with harmonic frequencies f _H2 , f _H3 are not taken into account.

In the upper part of FIG. 1, the subject's breathing and heartbeat are normal. Therefore, by applying a bandpass filter having a pass band corresponding to the general breathing rate to the radar signal, radar signal components having the fundamental frequency f _B1 and harmonic frequencies f _B2 and f _B3 are extracted from the radar signal. be able to. Then, by applying a bandpass filter having a passband corresponding to a general heart rate to the radar signal, radar signal components having a fundamental frequency f _H1 and harmonic frequencies f _H2 and f _H3 are extracted from the radar signal. be able to. In other words, radar signal components having fundamental/harmonic frequencies f _B1 , f _B2 , f _B3 derived from the subject's breathing, and fundamental/harmonic frequencies f _H1 , f _H2 , f _H3 originating from the subject's heartbeat are combined. It is possible to correctly separate the radar signal components that have Then, the breathing rate and heart rate of the subject can be accurately measured.

In the middle part of FIG. 1, the subject's breathing and heartbeat are slower than normal. Therefore, by applying a bandpass filter having a passband corresponding to the general breathing rate to the radar signal, the radar signal component having the fundamental frequency f _B1 and the harmonic frequency f _B2 can be extracted from the radar signal. However, the radar signal component with harmonic frequency f _B3 cannot be extracted from the radar signal. Then, by applying a bandpass filter having a passband corresponding to a general heart rate to the radar signal, radar signal components having a fundamental frequency f _H1 and harmonic frequencies f _H2 and f _H3 are extracted from the radar signal. However, the radar signal component having the harmonic frequency f _B3 originating from breathing cannot be removed from the radar signal. In other words, the radar signal component having the harmonic frequency _fB3 derived from the subject's breathing is erroneously extracted as the radar signal component having the fundamental frequency originating from the subject's heartbeat. Therefore, although it is possible to accurately measure the respiratory rate of the subject, it is not possible to accurately measure the heart rate of the subject.

In the lower part of FIG. 1, the subject's breathing and heartbeat are faster than normal. Therefore, by applying a bandpass filter having a pass band corresponding to the general breathing rate to the radar signal, radar signal components having the fundamental frequency f _B1 and harmonic frequencies f _B2 and f _B3 are extracted from the radar signal. However, the radar signal component with the fundamental frequency f _H1 originating from the heartbeat cannot be removed from the radar signal. Then, by applying a bandpass filter having a pass band corresponding to a general heart rate to the radar signal, radar signal components having harmonic frequencies f _H2 and f _H3 can be extracted from the radar signal. The radar signal component with fundamental frequency f _H1 cannot be extracted from the radar signal. That is, a radar signal component having a harmonic frequency f _H2 derived from the subject's heartbeat is erroneously extracted as a radar signal component having a fundamental frequency originating from the subject's heartbeat. Therefore, although it is possible to accurately measure the respiratory rate of the subject, it is not possible to accurately measure the heart rate of the subject.

Therefore, in order to solve the above problems, the present disclosure provides a radar having a fundamental frequency as a radar signal component derived from the breathing and heartbeat of the subject when measuring the breathing rate and heart rate of the subject using a radar. It is an object of the present invention to accurately measure the respiratory rate and heart rate of a subject even when not only signal components but also radar signal components having harmonic frequencies are present.

In order to solve the above problem, it was decided to extract the radar signal component having the maximum peak frequency of the frequency conversion result of the radar signal as the radar signal component having the fundamental frequency derived from the breathing of the subject. Then, a radar signal component having a harmonic frequency originating from the subject's breathing can be identified. Then, radar signal components having a fundamental frequency and harmonic frequencies derived from the subject's breathing can be removed from the radar signal. Furthermore, the radar signal component having the maximum peak frequency of the frequency conversion results of the remaining radar signals can be extracted as the radar signal component having the fundamental frequency derived from the heartbeat of the subject.

Specifically, the present disclosure provides a respiration rate measuring unit that frequency-converts a radar signal reflected from a subject and measures the respiratory rate of the subject based on the maximum peak frequency of the frequency conversion result of the radar signal. and removing a radar signal component originating from the subject's respiration from the radar signal by removing from the radar signal a radar signal component having the maximum peak frequency of the frequency conversion result of the radar signal and its harmonic frequency. After that, a respiratory component removal unit generates a heartbeat radar signal by extracting a radar signal component derived from the heartbeat of the subject, and a respiratory component removal unit that converts the frequency of the heartbeat radar signal and detects the maximum peak of the frequency conversion result of the heartbeat radar signal. The respiratory heart rate measuring device is characterized by comprising: a heart rate measuring section that measures the heart rate of the subject based on frequency.

The present disclosure also provides a respiration rate measuring step of converting the frequency of a radar signal reflected from the subject and measuring the respiration rate of the subject based on the maximum peak frequency of the frequency conversion result of the radar signal; By removing the radar signal component having the maximum peak frequency of the frequency conversion result of the radar signal and its harmonic frequency from the radar signal, the radar signal component originating from the respiration of the subject is removed from the radar signal. , a step of removing a respiratory component to generate a heartbeat radar signal by extracting a radar signal component derived from the heartbeat of the subject, and converting the frequency of the heartbeat radar signal based on the maximum peak frequency of the frequency conversion result of the heartbeat radar signal. and a heart rate measuring step of measuring the heart rate of the subject.

According to these configurations, even when there are not only radar signal components having a fundamental frequency but also radar signal components having harmonic frequencies as radar signal components derived from the subject's breathing and heartbeat, the subject's breathing and heartbeat can be detected. It is possible to accurately measure the number of heartbeats and heart rate.

Further, in the present disclosure, when calculating the amplitude and phase of a radar signal component having the maximum peak frequency and the harmonic frequency of the frequency conversion result of the radar signal, the respiratory component removal unit converts the frequency of the radar signal. The respiratory heart rate measuring device is characterized in that the absolute value of the error value obtained by removing the resulting radar signal component having the maximum peak frequency and the harmonic frequency from the radar signal becomes a minimum value.

According to this configuration, the radar signal having the fundamental frequency and harmonic frequencies originating from the subject's breathing can be transmitted without applying a band removal filter at the fundamental frequency and harmonic frequencies originating from the subject's breathing to the radar signal. components can be easily removed from the radar signal.

Further, in the present disclosure, when calculating the amplitude and phase of a radar signal component having the maximum peak frequency and the harmonic frequency of the frequency conversion result of the radar signal, the respiratory component removal unit converts the frequency of the radar signal. The respiratory heart rate measuring device is characterized in that it refers to the maximum peak frequency of the result and the amplitude and phase at the harmonic frequency.

With this configuration as well, the radar signal component having the fundamental frequency and harmonic frequencies originating from the subject's breathing can be removed without applying a band removal filter at the fundamental frequency and harmonic frequencies originating from the subject's breathing to the radar signal. can be easily removed from the radar signal.

Further, in the present disclosure, when applying a band removal filter at the maximum peak frequency of the frequency conversion result of the radar signal and the harmonic frequency to the radar signal, This is a respiratory heart rate measuring device characterized by compensating for linear distortion signal components caused by characteristics.

According to this configuration, even when applying a band removal filter at the fundamental frequency and harmonic frequencies originating from the breathing of the subject to the radar signal, the radar signal having the fundamental frequency and harmonic frequencies originating from the breathing of the subject components can be reliably removed from the radar signal.

Further, in the present disclosure, the heart rate measuring unit frequency-converts a cross-correlation result between the heartbeat radar signal and a reference heartbeat radar signal that pseudo-simulates the heartbeat radar signal, and The respiratory heart rate measuring device is characterized in that the heart rate of the subject is measured based on the maximum peak frequency of the frequency conversion result.

According to this configuration, even when a noise component having a high frequency originating from the respiratory heart rate measuring device or a signal component having a low frequency originating from the subject's breathing is superimposed on or remains on the heart rate radar signal, the The heart rate of the sample can be measured accurately.

Further, in the present disclosure, the respiration rate measurement unit calculates the amount of weight that a radar signal component having a maximum peak frequency of the frequency conversion result of the radar signal occupies in the entire frequency conversion result of the radar signal. The heart rate measurement unit evaluates the degree of reliability of the measurement result of the respiratory rate of the subject, and determines whether the radar signal component having the maximum peak frequency of the frequency conversion result of the heart rate radar signal is the result of the frequency conversion of the heart rate radar signal. The respiration heart rate measuring device is characterized in that the degree of reliability of the measurement result of the heart rate of the subject is evaluated based on the magnitude of weighting in the whole.

According to this configuration, the reliability of the measurement results of the breathing rate and heart rate of the subject can be evaluated. Then, when the reliability of the measurement result is higher/lower than the threshold value, the measurement result can be adopted/discarded. Furthermore, when the threshold value for the reliability of the measurement result is high/low, the measurement result can be output with emphasis on accuracy/real-time performance.

As described above, the present disclosure provides that when measuring the respiration rate and heart rate of a subject using radar, not only the radar signal component having a fundamental frequency but also the radar signal component derived from the respiration and heartbeat of the subject are used. Even when radar signal components having harmonic frequencies are present, the respiratory rate and heart rate of the subject can be accurately measured.

FIG. 3 is a diagram illustrating a respiration heart rate measurement process of the prior art. FIG. 1 is a diagram showing a respiratory heart rate measurement system of the present disclosure. FIG. 3 is a diagram illustrating a respiratory heart rate measurement procedure of the present disclosure. FIG. 3 is a diagram illustrating a first respiration measurement process of the present disclosure. FIG. 7 is a diagram illustrating a second respiration measurement process of the present disclosure. FIG. 7 is a diagram illustrating a third respiration measurement process of the present disclosure. FIG. 7 is a diagram illustrating a third respiration measurement process of the present disclosure. FIG. 3 is a diagram illustrating a first heartbeat measurement process of the present disclosure. FIG. 7 is a diagram illustrating a second heartbeat measurement process of the present disclosure. FIG. 3 is a diagram illustrating a respiration rate evaluation process of the present disclosure. FIG. 3 is a diagram illustrating heart rate evaluation processing according to the present disclosure. FIG. 3 is a diagram showing respiration measurement results of the present disclosure.

Embodiments of the present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of implementation of the present disclosure, and the present disclosure is not limited to the following embodiments.

FIG. 2 shows a respiratory heart rate measurement system of the present disclosure. FIG. 3 shows the respiratory heart rate measurement procedure of the present disclosure. The respiratory heart rate measuring system S includes a radar transmitting/receiving device 1, a respiratory heart rate measuring device 2, and a respiratory heart rate display device 3, and uses the radar transmitting/receiving device 1 to transmit a radar signal to be irradiated to the subject T. In addition to receiving the radar signal reflected from the subject T, the respiratory rate and heart rate of the subject T can be displayed using the respiratory heart rate display device 3. The respiratory heart rate measuring device 2 includes a respiratory rate measuring section 21, a respiratory component removing section 22, and a heart rate measuring section 23, and can be realized by installing the respiratory heart rate measuring program shown in FIG. 3 into a computer.

FIG. 4 shows the first respiration measurement process of the present disclosure. In FIG. 4, the In-phase component and the Quadrature-phase component are superimposed. The respiration rate measurement unit 21 frequency-converts the radar signal S(t) reflected from the subject T, and measures the respiration of the subject T based on the maximum peak frequency f _B1 of the frequency conversion result of the radar signal S(t). The number = 60f _B1 /min is measured (step S1). That is, the respiration rate measurement unit 21 uses the radar signal component having the maximum peak frequency f _B1 of the frequency conversion result of the radar signal S(t) as the radar signal component having the fundamental frequency f _B1 derived from the breathing of the subject T. Extract. Then, the respiration rate measuring unit 21 identifies radar signal components having harmonic frequencies f _B2 and f _B3 (further harmonic frequencies are omitted) derived from the breathing of the subject T.

Therefore, radar signal components derived from the breathing and heartbeat of the subject T include not only radar signal components having fundamental frequencies f _B1 and f _H1 but also radar signal components having harmonic frequencies f _B2 , f _B3 , f _H2 , and f _H3 . Even when a signal component exists, the respiratory rate of the subject T = 60 f _B1 /min can be accurately measured. Note that as the radar signal component derived from the breathing of the subject T, a radar signal component having a subharmonic frequency such as half of the fundamental frequency may be considered.

The respiratory component removing unit 22 removes the radar signal component having the maximum peak frequency f _B1 of the frequency conversion result of the radar signal S(t) and its harmonic frequencies f _B2 and f _B3 from the radar signal S(t) (step S2). In other words, the respiratory component removal unit 22 removes the radar signal component derived from the breathing of the subject T from the radar signal S(t), and then extracts the radar signal component derived from the heartbeat of the subject T from the heartbeat radar signal. S _H (t) is generated (step S3).

ここで、ａ_０＋ｂ_０ｔは、トレンド成分を表し、ａ_ｉ、ｂ_ｉは、周波数ｆ_Ｂ１、ｆ_Ｂ２、ｆ_Ｂ３を有するレーダ信号成分のうちの、ｃｏｓ成分の振幅及びｓｉｎ成分の振幅を表す。なお、トレンド成分として、ａ_０＋ｂ_０ｔ＋ｃ_０ｔ^２＋・・・を用いてもよい。 Specifically, when the respiratory component removing unit 22 calculates the amplitude and phase of the radar signal component having the maximum peak frequency f _B1 and harmonic frequencies f _B2 and f _B3 of the frequency conversion result of the radar signal S(t), , the absolute value of the error value obtained by removing the radar signal components having the maximum peak frequency f _B1 and harmonic frequencies f _B2 and f _B3 of the frequency conversion result of the radar signal S (t) from the radar signal S (t) is the minimum value. Make it so that Then, the heartbeat radar signal S _H (t) is expressed by Equation 1.

Here, a ₀ + b ₀ t represents a trend component, and a _i and b _i represent the amplitude of the cos component and the amplitude of the sine component among the radar signal components having frequencies f _B1 , f _B2 , and f _B3 . represent. Note that a ₀ +b ₀ t+c ₀ t ² +... may be used as the trend component.

Therefore, without applying a band removal filter at the fundamental frequency f _B1 and harmonic frequencies f _B2 and f _B3 originating from the breathing of the subject T to the radar signal S(t), the fundamental frequency originating from the breathing of the subject T can be removed. Radar signal components having frequency f _B1 and harmonic frequencies f _B2 , f _B3 can be easily removed from radar signal S(t). Note that as the radar signal component derived from the breathing of the subject T, a radar signal component having a subharmonic frequency such as half of the fundamental frequency may be removed.

FIG. 5 shows the second respiration measurement process of the present disclosure. In FIG. 5, the In-phase component and the Quadrature-phase component are superimposed. Regarding step S1, the second respiration measurement process shown in FIG. 5 is similar to the first respiration measurement process shown in FIG. 4.

The respiratory component removing unit 22 removes the radar signal component having the maximum peak frequency f _B1 of the frequency conversion result of the radar signal S(t) and its harmonic frequencies f _B2 and f _B3 from the radar signal S(t) (step S2). In other words, the respiratory component removal unit 22 removes the radar signal component derived from the breathing of the subject T from the radar signal S(t), and then extracts the radar signal component derived from the heartbeat of the subject T from the heartbeat radar signal. S _H (t) is generated (step S3).

ここで、ａ_０＋ｂ_０ｔは、トレンド成分を表し、ａ_ｉ、ｂ_ｉは、周波数ｆ_Ｂ１、ｆ_Ｂ２、ｆ_Ｂ３を有するレーダ信号成分のうちの、ｃｏｓ成分の振幅及びｓｉｎ成分の振幅を表す。なお、トレンド成分として、ａ_０＋ｂ_０ｔ＋ｃ_０ｔ^２＋・・・を用いてもよい。 Specifically, when the respiratory component removing unit 22 calculates the amplitude and phase of the radar signal component having the maximum peak frequency f _B1 and harmonic frequencies f _B2 and f _B3 of the frequency conversion result of the radar signal S(t), , the amplitude and phase at the maximum peak frequency f _B1 and harmonic frequencies f _B2 and f _B3 of the frequency conversion result of the radar signal S(t) are referred to. Note that for the maximum peak frequency f _B1 and harmonic frequencies f _B2 and f _B3 of the frequency conversion result of the radar signal S(t), the amplitude is shown, but the phase is not shown. The heartbeat radar signal S _H (t) is expressed by Equation 2.

Here, a ₀ + b ₀ t represents a trend component, and a _i and b _i represent the amplitude of the cos component and the amplitude of the sine component among the radar signal components having frequencies f _B1 , f _B2 , and f _B3 . represent. Note that a ₀ +b ₀ t+c ₀ t ² +... may be used as the trend component.

Therefore, without applying a band removal filter at the fundamental frequency f _B1 and harmonic frequencies f _B2 and f _B3 originating from the breathing of the subject T to the radar signal S(t), the fundamental frequency originating from the breathing of the subject T can be removed. Radar signal components having frequency f _B1 and harmonic frequencies f _B2 , f _B3 can be easily removed from radar signal S(t). Note that as the radar signal component derived from the breathing of the subject T, a radar signal component having a subharmonic frequency such as half of the fundamental frequency may be removed.

The third respiration measurement process of the present disclosure is shown in FIGS. 6 and 7. In FIGS. 6 and 7, the In-phase component and the Quadrature-phase component are superimposed. Regarding step S1, the third respiration measurement process shown in FIGS. 6 and 7 is the same as the first respiration measurement process shown in FIG. 4.

The respiratory component removing unit 22 removes the radar signal component having the maximum peak frequency f _B1 of the frequency conversion result of the radar signal S(t) and its harmonic frequencies f _B2 and f _B3 from the radar signal S(t) (step S2). In other words, the respiratory component removal unit 22 removes the radar signal component derived from the breathing of the subject T from the radar signal S(t), and then extracts the radar signal component derived from the heartbeat of the subject T from the heartbeat radar signal. S _H (t) is generated (step S3).

Specifically, the respiratory component removal unit 22 applies a band removal filter at the maximum peak frequency f _B1 and harmonic frequencies f _B2 and f _B3 of the frequency conversion result of the radar signal S(t) to the radar signal S(t). When applied, it compensates for linear distortion signal components due to the frequency characteristics of the band-rejection filter. Note that the maximum peak frequency f _B1 and harmonic frequencies f _B2 and f _B3 of the frequency conversion result of the radar signal S(t) are specified, and the frequency characteristics of the band removal filter are known, so the frequency of the band removal filter is The linear distortion signal component due to the characteristic can be calculated.

In the third stage of FIG. 6, a collective band removal filter is applied, and radar signal components having frequencies from the maximum peak frequency f _B1 to the harmonic frequency f _B3 are collectively removed. In the third stage of FIG. 7, a comb-shaped band rejection filter is applied, and radar signal components having maximum peak frequency f _B1 , harmonic frequency f _B2 and harmonic frequency f _B3 are individually removed.

Therefore, even when applying a band removal filter at the fundamental frequency f _B1 and harmonic frequencies f _B2 and f _B3 derived from the breathing of the subject T to the radar signal S(t), the fundamental frequency f B1 originating from the breathing of the subject T is applied to the radar signal S(t). Radar signal components having frequency f _B1 and harmonic frequencies f _B2 , f _B3 can be reliably removed from radar signal S(t). Note that as the radar signal component derived from the breathing of the subject T, a radar signal component having a subharmonic frequency such as half of the fundamental frequency may be removed.

FIG. 8 shows the first heart rate measurement process of the present disclosure. In FIG. 8, the In-phase component and the Quadrature-phase component are superimposed. The heart rate measuring unit 23 frequency-converts the heart rate radar signal S _H (t), and based on the maximum peak frequency f _H1 of the frequency conversion result of the heart rate radar signal S _H (t), the heart rate of the subject T = 60f. _H1 /min is measured (step S4). That is, the heart rate measuring unit 23 converts the radar signal component having the maximum peak frequency f _H1 of the frequency conversion result of the heart rate radar signal S _H (t) into the radar signal component having the fundamental frequency f _H1 derived from the heartbeat of the subject T. Extract as a component. Then, the heart rate measuring unit 23 identifies radar signal components having harmonic frequencies f _H2 and f _H3 (further harmonic frequencies are omitted) derived from the heartbeat of the subject T.

Here, in the frequency conversion result of the heartbeat radar signal S _H (t), some radar signal components having the fundamental frequency f _B1 and harmonic frequency f _B2 derived from the breathing of the subject T remain, but the is small compared to the radar signal component with fundamental frequency f _H1 originating from the heartbeat of T.

Therefore, radar signal components derived from the breathing and heartbeat of the subject T include not only radar signal components having fundamental frequencies f _B1 and f _H1 but also radar signal components having harmonic frequencies f _B2 , f _B3 , f _H2 , and f _H3 . Even when a signal component exists, the heart rate of the subject T = 60 f _H1 /min can be accurately measured. Note that as the radar signal component derived from the heartbeat of the subject T, a radar signal component having a subharmonic frequency such as half of the fundamental frequency may be considered.

FIG. 9 shows the second heart rate measurement process of the present disclosure. In FIG. 9, the In-phase component and the Quadrature-phase component are superimposed. The heart rate measuring unit 23 calculates a cross-correlation result S C between the heart rate radar signal S _H (t) and a reference heart rate radar signal _{S S (} t) which is a pseudo model of the heart rate radar signal S _H (t). (t) is frequency-converted, and the heart rate of the subject T = 60 f _H1 /min is measured based on the maximum peak frequency f _H1 of the frequency conversion result of the cross-correlation result S _C (t) (step S4). That is, the heart rate measuring unit 23 converts the radar signal component having the maximum peak frequency f _H1 of the frequency conversion result of the cross-correlation result S _C (t) into the radar signal component having the fundamental frequency f _H1 derived from the heartbeat of the subject T. Extract as a component. Then, the heart rate measurement unit 23 identifies radar signal components having harmonic frequencies f _H2 and f _H3 (further harmonic frequencies are omitted) derived from the heartbeat of the subject T.

ここで、Ｃｏｒｒは、２個の引数の間の時間領域の相関関数を表す。 Here, as the reference heart rate radar signal S _S (t), a reference heart rate radar signal S _COS (t) which is a cos basis and a reference heart rate radar signal S _SIN (t) which is a sin basis are prepared. Then, the cross-correlation shown in Equation 3 is calculated as the cross-correlation result S _C (t).

Here, Corr represents a time domain correlation function between two arguments.

Therefore, the noise component having a high frequency originating from the respiratory heart rate measuring device 2 and the signal component having low frequencies f _B1 , f _B2 , f _B3 originating from the breathing of the subject T are the heart rate radar signal S _H (t). Even when the heart rate of the subject T is superimposed or remains, the heart rate of the subject T = 60 f _H1 /min can be accurately measured. Note that as the radar signal component derived from the heartbeat of the subject T, a radar signal component having a subharmonic frequency such as half of the fundamental frequency may be considered.

FIG. 10 shows the respiration rate evaluation process of the present disclosure. In FIG. 10, the In-phase component and the Quadrature-phase component are superimposed. The respiration rate measurement unit 21 calculates the frequency of the radar signal S(t) based on the weighting that the radar signal component having the maximum peak frequency _fB1 of the frequency conversion result of the radar signal S(t) occupies in the entire frequency conversion result of the radar signal S(t). , the reliability of the measurement result of the respiratory rate of the subject T = 60 f _B1 /min is evaluated (step S5).

Specifically, the respiration rate measurement unit 21 calculates the reliability of the measurement result of the respiration rate of the subject T as follows: (signal component of maximum peak frequency f _B1 )/(sum of signal components of all peak frequencies or higher peak frequencies) Calculate. Furthermore, as the reliability of the measurement result of the respiratory rate of the subject T, it is also possible to use (sum of signal components of peak frequencies f _B1 , f _B2 , f _B3 )/(sum of signal components of all peak frequencies or upper peak frequencies). good. Then, when the reliability of the measurement result of the respiratory rate of the subject T is higher/lower than the threshold value, the respiratory rate measurement unit 21 adopts/discards the measurement result of the respiratory rate of the subject T. Furthermore, when the threshold value for the measurement result of the respiratory rate of the subject T is high/low, the respiratory rate measurement unit 21 outputs the measurement result of the respiratory rate of the subject T with emphasis on accuracy/real-time performance.

FIG. 11 shows the heart rate evaluation process of the present disclosure. In FIG. 11, the In-phase component and the Quadrature-phase component are superimposed. The heart rate measuring unit 23 calculates the weight that the radar signal component having the maximum peak frequency f _H1 of the frequency conversion result of the heartbeat radar signal S _H (t) accounts for in the entire frequency conversion result of the heartbeat radar signal S _H (t). Based on the magnitude, the reliability of the measurement result of the heart rate of the subject T = 60 f _H1 /min is evaluated (step S6).

Specifically, the heart rate measurement unit 23 calculates the reliability of the heart rate measurement result of the subject T by (signal component of maximum peak frequency f _H1 )/(sum of signal components of all peak frequencies or higher peak frequencies). Calculate. Note that as the reliability of the measurement result of the heart rate of the subject T, (sum of signal components of peak frequencies f _H1 , f _H2 , f _H3 )/(sum of signal components of all peak frequencies or upper peak frequencies) can also be used. good. Then, when the reliability of the measurement result of the heart rate of the subject T is higher/lower than the threshold value, the heart rate measurement unit 23 adopts/discards the measurement result of the heart rate of the subject T. Further, when the threshold value for the measurement result of the heart rate of the subject T is high/low, the heart rate measurement unit 23 outputs the measurement result of the heart rate of the subject T with emphasis on accuracy/real time.

The respiration measurement results of the present disclosure are shown in FIG. 12. The vertical line at the top of FIG. 12 indicates that the measurement result of the respiratory rate of the subject T is rejected because the reliability of the measurement result of the respiratory rate of the subject T is lower than the threshold value. The white circle at the bottom of FIG. 12 indicates that the measurement result of the respiratory rate of the subject T is adopted because the reliability of the measurement result of the respiratory rate of the subject T is higher than the threshold value. Furthermore, even when the reliability of the measurement result of the respiration rate of the subject T is high compared to the threshold value, if the measurement result of the respiration rate of the subject T changes suddenly, the measurement result of the respiration rate of the subject T may be rejected. You may.

The respiration heart rate measurement device and the respiration heart rate measurement program of the present disclosure use a radar having a fundamental frequency as a radar signal component derived from the respiration and heartbeat of the object when measuring the respiration rate and heart rate of the object using radar. Even when not only signal components but also radar signal components having harmonic frequencies are present, the respiratory rate and heart rate of the subject can be accurately measured.

S: Respiratory heart rate measuring system T: Subject 1: Radar transmitting/receiving device 2: Respiratory heart rate measuring device 3: Respiratory heart rate display device 21: Respiratory rate measuring section 22: Respiratory component removing section 23: Heart rate measuring section

Claims (8)

a respiration rate measuring unit that converts the frequency of a radar signal reflected from the subject and measures the respiratory rate of the subject based on the maximum peak frequency of the frequency conversion result of the radar signal;
By removing from the radar signal the radar signal component having the maximum peak frequency of the frequency conversion result of the radar signal and its harmonic frequency, the radar signal component originating from the respiration of the subject is removed from the radar signal. a respiratory component removal unit that generates a heartbeat radar signal by extracting a radar signal component derived from the heartbeat of the subject;
a heart rate measuring unit that converts the frequency of the heart rate radar signal and measures the heart rate of the subject based on the maximum peak frequency of the frequency conversion result of the heart rate radar signal ,
The respiratory component removal unit calculates the maximum peak frequency and phase of the radar signal component having the maximum peak frequency and the harmonic frequency of the frequency conversion result of the radar signal. The absolute value of the error value obtained by removing the radar signal component having the harmonic frequency from the radar signal is set to a minimum value.
A respiratory heart rate measuring device characterized by: a respiration rate measuring unit that converts the frequency of a radar signal reflected from the subject and measures the respiratory rate of the subject based on the maximum peak frequency of the frequency conversion result of the radar signal;
By removing from the radar signal the radar signal component having the maximum peak frequency of the frequency conversion result of the radar signal and its harmonic frequency, the radar signal component originating from the respiration of the subject is removed from the radar signal. a respiratory component removing unit that generates a heartbeat radar signal by extracting a radar signal component derived from the heartbeat of the subject;
a heart rate measuring unit that converts the frequency of the heart rate radar signal and measures the heart rate of the subject based on the maximum peak frequency of the frequency conversion result of the heart rate radar signal ,
The heart rate measuring unit frequency-converts the cross-correlation result between the heartbeat radar signal and a reference heartbeat radar signal using a mother wavelet function that simulates the heartbeat radar signal, and converts the cross-correlation result. Measure the heart rate of the subject based on the maximum peak frequency of the frequency conversion result.
A respiratory heart rate measuring device characterized by: The respiratory component removal unit calculates the maximum peak frequency and phase of the frequency conversion result of the radar signal when calculating the amplitude and phase of the radar signal component having the maximum peak frequency and the harmonic frequency of the frequency conversion result of the radar signal. The respiratory heart rate measuring device according to claim 2 , wherein the absolute value of an error value obtained by removing the radar signal component having the harmonic frequency from the radar signal is a minimum value. The respiratory component removal unit calculates the maximum peak frequency and phase of the radar signal component having the maximum peak frequency and the harmonic frequency of the frequency conversion result of the radar signal. The respiratory heart rate measuring device according to claim 2 , characterized in that the amplitude and phase at the harmonic frequency are referred to. The respiratory component removing unit removes linear distortion due to frequency characteristics of the band removal filter when applying the band removal filter at the maximum peak frequency of the frequency conversion result of the radar signal and the harmonic frequency to the radar signal. The respiratory heart rate measuring device according to claim 2 , wherein the respiratory heart rate measuring device compensates for signal components. The respiration rate measurement unit measures the respiration rate of the subject based on the weighting that a radar signal component having the maximum peak frequency of the frequency conversion result of the radar signal occupies in the entire frequency conversion result of the radar signal. Evaluate the reliability of measurement results,
The heart rate measuring unit calculates the heart rate of the subject based on the weight that a radar signal component having the maximum peak frequency of the frequency conversion result of the heart rate radar signal occupies in the entire frequency conversion result of the heart rate radar signal. The respiratory heart rate measuring device according to any one of claims 1 to 5, characterized in that the reliability level of the measurement result of the number of heartbeats is evaluated. a respiration rate measuring step of converting the frequency of a radar signal reflected from the subject and measuring the respiration rate of the subject based on the maximum peak frequency of the frequency conversion result of the radar signal;
By removing from the radar signal the radar signal component having the maximum peak frequency of the frequency conversion result of the radar signal and its harmonic frequency, the radar signal component originating from the respiration of the subject is removed from the radar signal. a respiratory component removal step of generating a heartbeat radar signal by extracting a radar signal component derived from the heartbeat of the subject;
a heart rate measuring step of converting the frequency of the heart rate radar signal and measuring the heart rate of the subject based on the maximum peak frequency of the frequency conversion result of the heart rate radar signal;
have the computer execute the following in order ,
The respiratory component removing step includes calculating the maximum peak frequency and phase of the radar signal component having the maximum peak frequency and the harmonic frequency of the frequency conversion result of the radar signal. The absolute value of the error value obtained by removing the radar signal component having the harmonic frequency from the radar signal is set to a minimum value.
A respiratory heart rate measurement program. a respiration rate measuring step of converting the frequency of a radar signal reflected from the subject and measuring the respiration rate of the subject based on the maximum peak frequency of the frequency conversion result of the radar signal;
By removing from the radar signal the radar signal component having the maximum peak frequency of the frequency conversion result of the radar signal and its harmonic frequency, the radar signal component originating from the respiration of the subject is removed from the radar signal. a respiratory component removal step of generating a heartbeat radar signal by extracting a radar signal component derived from the heartbeat of the subject;
a heart rate measuring step of converting the frequency of the heart rate radar signal and measuring the heart rate of the subject based on the maximum peak frequency of the frequency conversion result of the heart rate radar signal;
have the computer execute the following in order ,
The heart rate measuring step frequency-converts the cross-correlation result between the heartbeat radar signal and a reference heartbeat radar signal using a mother wavelet function that simulates the heartbeat radar signal, and converts the cross-correlation result. Measure the heart rate of the subject based on the maximum peak frequency of the frequency conversion result.
A respiratory heart rate measurement program.

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