JP2017104360A - Acquisition device of biological information, acquisition program of biological information and acquisition method of biological information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce burden to a subject in comparison with the case of using a polysomnography at sleep and detect a heart beat interval with high accuracy in comparison with a conventional system.SOLUTION: An acquisition device (S) of biological information includes: respiratory waveform calculation means (C5) for calculating a first respiratory waveform (22) based on a first stride (N1) and a vibration waveform (21), and calculating a second respiratory waveform (22) based on a second stride (N2) and a vibration waveform (21) having a period different from the first stride (N1); pulse waveform calculation means (C6) for calculating a first pulse waveform (23) obtained by subtracting the first respiratory waveform (22) from the vibration waveform (21), and calculating a second pulse waveform (23) obtained by subtracting the second respiratory waveform (22) from the vibration waveform (21); and index calculation means (C14) for calculating a heart rate variation index based on the pulse waveform (23), in which each peak interval (RRI) is abnormal and the number of peak intervals is small, from each pulse waveform (23).SELECTED DRAWING: Figure 3

Description

  The present invention relates to a biological information acquisition apparatus, a biological information acquisition program, and a biological information acquisition method for acquiring biological information of a subject, and in particular, a biological information acquisition apparatus capable of acquiring a pulse wave signal, and a biological information acquisition program. And a method for acquiring biological information.

  Conventionally, in order to examine a human sleep stage, sleep polysomnography (PSG) is used, and an electroencephalogram, an electrooculogram, and an electromyogram during sleep are measured and determined. However, this detection of sleep depth and sleep cycle generally requires a large number of electrodes to be attached to the human body in order to collect brain waves, etc., and preparations are very troublesome, and there are also problems that prevent sleep. I couldn't measure it at home.

In order to reduce the burden on the test subject, a method of measuring body movement, respiration, and heart rate by installing a piezoelectric sensor (pressure sensor) under the bedding is not a method of attaching electrodes to the human body. ~ 3.
Patent Documents 4 to 7 describe techniques using a contact-type photoelectric pulse wave sensor.
Furthermore, Patent Documents 8 to 11 describe techniques for measuring body movement, respiration, and heartbeat in a non-contact manner using a microwave radar. Patent Document 8 describes a technique for calculating a respiration rate and a heart rate using fast Fourier transform (FFT). Patent Documents 9 and 10 describe a method for detecting a human body abnormal state by monitoring the position and movement of a person based on the intensity of a radar reflected wave. Patent Document 11 describes that a temporal change of an IQ norm signal is calculated from orthogonal I and Q output signals of Doppler radar and used for sleep stage estimation and autonomic nerve activity evaluation.

JP 2014-147597 A Japanese Patent No. 4582642 Japanese Unexamined Patent Publication No. 2015-42267 Japanese Patent Laying-Open No. 2015-198094 Japanese Patent Laying-Open No. 2015-178011 JP 2010-179133 A Japanese Patent No. 3353552 Japanese Patent No. 3057438 Japanese Patent No. 5350721 JP 2014-217453 A JP 2014-307553 A

(Problems of conventional technology)
In the techniques described in Patent Documents 1 to 3, although the burden on the subject is small because the invasiveness to the subject is lower than in the case where electrodes are attached to the human body, body motion and vibration (breathing, pulse wave) Heart rate can be extracted for measurement using the method via bedding, but the heart rate interval (pulse wave) for calculating heart rate variability (HRV) indicating sleep stage and autonomic nervous activity There was a problem that it was not possible to accurately detect (equal to the interval). For example, the heart rate is calculated as 60000 / average heart rate interval [times / minute] using an average value [ms] of heart beat intervals in 10 beats. It is important that the time series data itself is accurate. Therefore, in patent documents 1-3, there exists a problem that it is difficult to detect correctly HRV required when determining the state and quality of sleep.

In the technique using the contact type photoelectric pulse wave sensor described in Patent Documents 4 to 7, there is a problem that noise such as body movement is mixed, the sensor is detached from the fingertip, or a contact failure with the fingertip is likely to occur. is there.
In the technique using the microwave radar described in Patent Documents 8 to 11, detection of body motion and respiratory signal is relatively easy, but extraction of pulse wave vibration having only a displacement of about 5% of respiratory vibration is performed on the body. There is a problem that it is difficult to extract pulse wave vibration due to the influence and disturbance of motion and respiratory vibration. In addition, in the technology using microwave radar, the pulse wave may not exist (the arteriole on the skin surface does not exist) in the irradiation area of the microwave radar, particularly in the central region where the intensity of the irradiation radio wave is secured. . In addition, the reflected radio wave intensity from the body surface may not be sufficient depending on the posture during sleep. That is, the pulse wave vibration may not be detected depending on the installation position of the microwave radar and the position, posture, and behavior of the subject during sleep.

  It is a technical object of the present invention to reduce the burden on the subject as compared to the case of using sleep polysomnography and to detect the heartbeat interval with higher accuracy than in the conventional method.

In order to solve the technical problem, the biological information acquisition apparatus according to claim 1 is provided.
A detection member that is arranged in a non-contact state to the subject and detects vibration of the surface of the subject,
Vibration waveform acquisition means for acquiring a vibration waveform that is a temporal history of vibration detected by the detection member;
The first respiration, which is a period for calculating the average of vibration information and is a temporal history of the average of vibration based on the first step width sufficiently short with respect to the breathing interval and the vibration waveform. Respiration that calculates a waveform and calculates a second respiratory waveform that is an average temporal history of vibration based on the second step width and the vibration waveform that are different in duration from the first step width. Waveform calculation means,
A pulse waveform that calculates a first pulse waveform obtained by subtracting the first respiratory waveform from the vibration waveform and calculates a second pulse waveform obtained by subtracting the second respiratory waveform from the vibration waveform. Computing means;
Peak selection means for selecting a peak in each pulse wave waveform;
Based on the peak selected by the peak selection means and a preset threshold value, the number of peak intervals in which the interval of each peak of the first pulse wave waveform is abnormal is detected, and based on the threshold value, An abnormal interval detecting means for detecting the number of peak intervals in which the interval of each peak of the second pulse wave waveform is abnormal;
An index calculation means for calculating a heart rate fluctuation index based on a pulse waveform with a small number of abnormal peak intervals;
It is provided with.

In order to solve the technical problem, the biological information acquisition apparatus according to claim 2 comprises:
A detection member that is arranged in a non-contact state to the subject and detects vibration of the surface of the subject,
From the vibration waveform that is a temporal history of vibration detected by the detection member, the first step width and the vibration waveform that are periods in which an average of vibration information is calculated and are short with respect to the breathing interval In the first pulse waveform calculated by subtracting the first respiratory waveform that is the average temporal history of vibrations calculated based on the peak, the peak selected by the peak selection means is preset. Based on a threshold value, a first interval abnormality number in which the interval of each peak of the first pulse wave waveform is abnormal, and a second step width having a period different from the first step width from the vibration waveform, In the second pulse waveform calculated by subtracting the second respiratory waveform that is the average temporal history of the vibration calculated based on the vibration waveform, the peak is selected by the peak selecting means Each of the second pulse wave waveforms based on the peak and the threshold value And detecting a second interval abnormality number having an abnormal peak interval, comparing the first interval abnormality number and the second interval abnormality number, and generating a pulse waveform having a small number of abnormal peak intervals. Based on an index calculating means for calculating a heart rate variability index,
It is provided with.

The invention according to claim 3 is the biological information acquisition device according to claim 1 or 2,
In each pulse waveform, for each waveform portion having a value higher than a preset reference value, the area surrounded by one waveform portion is larger than a preset threshold value and peaks in the one waveform portion. When there are a plurality of candidates, a peak candidate for selecting a peak candidate of the one waveform portion as a peak of the one waveform portion based on a peak interval of a waveform portion different from the one waveform portion. Selection means,
It is provided with.

In order to solve the technical problem, the biological information acquisition apparatus according to claim 4 is provided by:
A detection member that is arranged in a non-contact state to the subject and detects vibration of the surface of the subject,
Vibration waveform acquisition means for acquiring a vibration waveform that is a temporal history of vibration detected by the detection member;
A respiration waveform that is a period for calculating the average of vibration information and calculates a respiration waveform, which is a temporal history of the average of vibration, based on a step length sufficiently short with respect to a respiration interval and the vibration waveform And a computing means of
A pulse wave waveform calculating means for calculating a pulse waveform obtained by subtracting the respiratory waveform from the vibration waveform;
In the pulse waveform, for each waveform portion having a value higher than a preset reference value, the area surrounded by one waveform portion is larger than a preset threshold value, and a peak appears in the one waveform portion. Peak selection for selecting a peak candidate of the one waveform portion as a peak of the one waveform portion based on a peak interval of a waveform portion different from the one waveform portion when a plurality of candidates exist Means,
An index calculating means for calculating a heart rate fluctuation index based on the peak interval of the pulse wave waveform;
It is provided with.

The invention according to claim 5 is the biological information acquisition device according to any one of claims 1 to 4,
In the plurality of peak candidates detected in the pulse wave waveform, when the amplitude value of the peak candidate is smaller than a preset threshold value, the peak is excluded from the peak candidate and selected. Selection means,
It is provided with.

The invention according to claim 6 is the biological information acquisition apparatus according to any one of claims 1 to 5,
In the plurality of peak candidates detected in the pulse wave waveform, when the time interval between the set of peak candidates is smaller than a preset threshold, the set of peak candidates is The peak selection means for selecting a peak by excluding one peak candidate based on the interval between different peak candidates,
It is provided with.

The invention according to claim 7 is the biological information acquisition apparatus according to any one of claims 1 to 6,
A plurality of the detection members arranged on the surface of the subject,
It is provided with.

In order to solve the technical problem, the biological information acquisition program according to claim 8 is provided by:
Computer
Vibration waveform acquisition means for acquiring a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with the subject;
The first respiration, which is a period for calculating the average of vibration information and is a temporal history of the average of vibration based on the first step width sufficiently short with respect to the breathing interval and the vibration waveform. Respiration that calculates a waveform and calculates a second respiratory waveform that is an average temporal history of vibration based on the second step width and the vibration waveform that are different in duration from the first step width. Waveform calculation means,
A pulse waveform that calculates a first pulse waveform obtained by subtracting the first respiratory waveform from the vibration waveform and calculates a second pulse waveform obtained by subtracting the second respiratory waveform from the vibration waveform. Computing means,
Peak selection means for selecting a peak in each pulse wave waveform,
Based on the peak selected by the peak selection means and a preset threshold value, the number of peak intervals in which the interval of each peak of the first pulse wave waveform is abnormal is detected, and based on the threshold value, An abnormal interval detection means for detecting the number of peak intervals in which the interval between the peaks of the second pulse wave waveform is abnormal,
An index calculating means for calculating a heart rate variability index based on a pulse wave waveform with a small number of abnormal peak intervals,
It is made to function as.

In order to solve the technical problem, the biological information acquisition program according to claim 9 is provided by:
Computer
It is a period for calculating the average of vibration information from a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with respect to the subject, and with respect to a breathing interval In the first pulse wave waveform calculated by subtracting the first respiratory waveform that is the average temporal history of vibration calculated based on the first short-term step size and the vibration waveform, Based on a preset threshold value, a first interval abnormality number in which the interval of each peak of the first pulse wave waveform is abnormal, and a second period having a period different from the first step size based on the vibration waveform. In the second pulse waveform calculated by subtracting the second respiratory waveform, which is the average temporal history of vibration calculated based on the step size and the vibration waveform, based on the threshold value A second interval in which the interval between the peaks of the second pulse wave waveform is abnormal The calculation of an index for detecting a constant, comparing the first interval abnormality number and the second interval abnormality number, and calculating a heart rate variability index based on a pulse wave waveform with a small number of abnormal peak intervals means,
It is made to function as.

In order to solve the technical problem, the biological information acquisition program according to the invention of claim 10 includes:
Computer
Vibration waveform acquisition means for acquiring a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with the subject;
A respiration waveform that is a period for calculating the average of vibration information and calculates a respiration waveform, which is a temporal history of the average of vibration, based on a step length sufficiently short with respect to a respiration interval and the vibration waveform Computing means,
Pulse wave waveform calculation means for calculating a pulse waveform obtained by subtracting the respiratory waveform from the vibration waveform;
In the pulse waveform, for each waveform portion having a value higher than a preset reference value, the area surrounded by one waveform portion is larger than a preset threshold value, and a peak appears in the one waveform portion. When there are a plurality of candidates, the peak candidate of the one waveform portion that is closest to the temporal median value of the peaks of adjacent waveform portions that are adjacent in time to the one waveform portion is Means for selecting a peak to be selected as a peak of one waveform portion;
An index calculating means for calculating a heart rate variability index based on the peak interval of the pulse wave waveform;
It is made to function as.

In order to solve the technical problem, the biological information acquiring method according to the invention of claim 11 includes:
Obtaining a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with the subject;
The first respiration, which is a period for calculating the average of vibration information and is a temporal history of the average of vibration based on the first step width sufficiently short with respect to the breathing interval and the vibration waveform. A step of calculating a waveform and calculating a second respiratory waveform, which is an average temporal history of vibration, based on the second step width and the vibration waveform having a period different from the first step width. When,
Calculating a first pulse waveform obtained by subtracting the first respiratory waveform from the vibration waveform, and calculating a second pulse waveform obtained by subtracting the second respiratory waveform from the vibration waveform;
Selecting a peak in each pulse wave waveform;
Based on the peak selected in the peak selection step and a preset threshold, the number of peak intervals in which the interval of each peak of the first pulse wave waveform is abnormal is detected, and based on the threshold Detecting the number of peak intervals in which the interval between the peaks of the second pulse wave waveform is abnormal;
Calculating a heart rate variability index based on a pulse waveform with a small number of abnormal peak intervals;
It is characterized by performing.

In order to solve the technical problem, the biometric information acquisition method according to the invention described in claim 12 includes:
It is a period for calculating the average of vibration information from a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with respect to the subject, and with respect to a breathing interval In the first pulse wave waveform calculated by subtracting the first respiratory waveform that is the average temporal history of vibration calculated based on the first short-term step size and the vibration waveform, Based on a preset threshold value, a first interval abnormality number in which the interval of each peak of the first pulse wave waveform is abnormal, and a second period having a period different from the first step size based on the vibration waveform. In the second pulse waveform calculated by subtracting the second respiratory waveform, which is the average temporal history of vibration calculated based on the step size and the vibration waveform, based on the threshold value A second interval in which the interval between the peaks of the second pulse wave waveform is abnormal A constant number is detected, the first interval abnormality number and the second interval abnormality number are compared, and a heart rate fluctuation index is calculated based on a pulse wave waveform with a small number of abnormal peak intervals. And

In order to solve the technical problem, the biometric information acquiring method according to the invention described in claim 13 includes:
Obtaining a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with the subject;
A step of calculating a respiratory waveform that is a period for calculating an average of vibration information and is based on the vibration waveform and a step length sufficiently short with respect to a breathing interval and the vibration waveform. ,
Calculating a pulse waveform obtained by subtracting the respiratory waveform from the vibration waveform;
In the pulse waveform, for each waveform portion having a value higher than a preset reference value, the area surrounded by one waveform portion is larger than a preset threshold value, and a peak appears in the one waveform portion. When there are a plurality of candidates, the peak candidate of the one waveform portion that is closest to the temporal median value of the peaks of adjacent waveform portions that are adjacent in time to the one waveform portion is Selecting as a peak of one waveform portion;
Calculating a heart rate variability index based on the peak interval of the pulse wave waveform;
It is characterized by performing.

According to invention of Claim 1, 2, 4, 8-13, while reducing the burden on a test subject compared with the case where sleep polysomnography is used, a heartbeat interval is compared with the conventional system. It can be detected with high accuracy.
According to the third aspect of the present invention, when the area surrounded by one waveform portion of the pulse waveform is larger than a preset threshold value and there are a plurality of peak candidates in one waveform portion, When a candidate for a peak of one waveform portion that is closest to the temporal median of adjacent waveform portions adjacent to each other in time is not selected as a peak of the one waveform portion. In comparison, the heartbeat interval can be detected with high accuracy. Specifically, it is possible to remove the adverse effect that the peak shape of the pulse wave has been conventionally disturbed by the respiratory motion having a vibration displacement of about 20 times the pulse wave.

According to the fifth aspect of the present invention, it is possible to detect the heartbeat interval with higher accuracy than in the case where candidates for small amplitude peaks are not excluded.
According to the sixth aspect of the present invention, it is possible to detect a heartbeat interval with higher accuracy than in a case where a peak candidate having a small interval between peak candidates is not excluded.
According to the seventh aspect of the present invention, the detection failure of the pulse waveform is reduced as compared with the case where a plurality of detection members are not provided.

FIG. 1 is an overall explanatory diagram of a biometric information acquisition apparatus according to a first embodiment of the present invention. FIG. 2 is an explanatory diagram of the detection member according to the first embodiment. FIG. 3 is an explanatory diagram showing functions up to HRV calculation in the biological information acquisition apparatus according to the first embodiment of the present invention in a block diagram (functional block diagram). FIG. 4 is an explanatory diagram of an example of the waveform of the first embodiment, FIG. 4A is an explanatory diagram of a vibration waveform when the pulse wave component is large, FIG. 4B is an explanatory diagram of a respiratory waveform calculated from the waveform of FIG. 4C is an explanatory diagram of a pulse wave waveform calculated from the waveforms of FIGS. 4A and 4B. FIG. 5 is an explanatory diagram of an example of a waveform different from the waveform of FIG. 4, FIG. 5A is an explanatory diagram of a vibration waveform when the pulse wave component is small, and FIG. 5B is an explanatory diagram of a respiratory waveform calculated from the waveform of FIG. FIGS. 5C and 5C are explanatory diagrams of pulse wave waveforms calculated from the waveforms of FIGS. 5A and 5B. FIG. 6 is an explanatory diagram of a method of acquiring vibration waveform information according to the first embodiment. FIG. 7 is an explanatory diagram of a period for determining body movement according to the first embodiment. 8 is an explanatory diagram of a peak selection method according to the first embodiment, FIG. 8A is an explanatory diagram of a peak extraction method, FIG. 8B is an explanatory diagram of a method of excluding a peak having a small amplitude from a peak candidate, and FIG. 8C is an interval. It is explanatory drawing of the method of excluding a short peak candidate. FIG. 9 is an explanatory diagram of the processing for excluding candidates for respiratory effects according to the first embodiment. FIG. 10 is an explanatory diagram of a peak interval evaluation method according to the first embodiment, and is an explanatory diagram of a peak selected by excluding a peak candidate in each exclusion process from the pulse wave waveform shown in FIG. 8A. FIG. 11 is an explanatory diagram of the peak interval of Example 1, FIG. 11A is an explanatory diagram of an example of a vibration waveform, FIG. 11B is an explanatory diagram of a pulse waveform derived from the vibration waveform of FIG. 11A, and FIG. It is explanatory drawing of the peak space | interval (RRI space | interval) derived | led-out from this pulse wave waveform. FIG. 12 is an explanatory diagram of a graph obtained by performing fast Fourier transform on the waveform of the peak interval, where the horizontal axis represents frequency and the vertical axis represents power. FIG. 13 is an explanatory diagram of an example of HRV, FIG. 13A is a graph showing the activity of the parasympathetic nerve, and FIG. 13B is a graph showing the activity of the sympathetic nerve. FIG. 14 is a flowchart of biometric information acquisition processing according to the first embodiment. FIG. 15 is an explanatory diagram of a conventional method of calculating a pulse waveform, FIG. 15A is an explanatory diagram of a vibration waveform corresponding to FIG. 5A, and FIG. 15B is obtained by calculating with a step size of 0.8 seconds in FIG. FIG. 15C is an explanatory diagram of a respiratory waveform, and FIG. 15C is an explanatory diagram of a pulse waveform calculated from the vibration waveform of FIG. 15A and the respiratory waveform of FIG. 15B.

Next, specific examples of embodiments of the present invention (hereinafter referred to as examples) will be described with reference to the drawings, but the present invention is not limited to the following examples.
In the following description using the drawings, illustrations other than members necessary for the description are omitted as appropriate for easy understanding.

FIG. 1 is an overall explanatory diagram of a biometric information acquisition apparatus according to a first embodiment of the present invention.
In FIG. 1, the biometric information acquisition apparatus S according to the first embodiment of the present invention includes a bed (bed) 1 on which a human (subject) lies as an example of a subject. The bed 1 includes a mattress support 1a as a bed body and a mattress 1b supported by the mattress support 1a. The mattress 1b of Example 1 has a cushioning property for improving the sleeping comfort by being placed on the mattress support 1a. The mattress 1b is made of urethane or bedding such as a so-called air mattress (air mat or air bed) in which air is sealed.

Further, a microwave radar SN1 as an example of a detection device is supported on the lower surface of the mattress 1b. The microwave radar SN1 according to the first embodiment can detect vibrations of the body surface of the subject by transmitting and receiving microwaves (electromagnetic waves).
In the first embodiment, the microwave radar SN1 in the bed 1 is the first radar SN1a disposed at a position corresponding to the upper body of the subject, particularly the chest, and the second radar disposed at a position corresponding to the abdomen. Radar SN1b.

FIG. 2 is an explanatory diagram of the detection member according to the first embodiment.
In FIG. 2, each of the radars SN1a and SN1b according to the first embodiment has a configuration in which a total of nine microwave Doppler sensors 2 as an example of a detection member are arranged in a lattice shape of 3 × 3. Each microwave Doppler sensor 2 according to the first embodiment is configured by a commercially available sensor capable of transmitting and receiving two signals of an I channel and a Q channel whose phase is shifted by 90 degrees from the I channel.

In addition, the frequency of each microwave in Example 1 is open to the public and does not require a specific license, and passes through the outer surface of the mattress 1b, the clothes of the subject, and the like. It is desirable to employ a frequency that can be transmitted to the body surface of the specimen and can receive a reflected wave from the subject. Therefore, in Example 1, the frequency of the microwave is set in advance to about 24 [GHz].
The mattress 1b is also free of coil springs or the like that may adversely affect microwave transmission / reception, and is preferably, for example, the urethane low-resilience mattress or air mattress.

In FIG. 1, the biological information acquisition apparatus S according to the first embodiment includes a client personal computer (apparatus body, computer) PCa as an information terminal to which the microwave radar SN1 is connected. The client personal computer PCa according to the first embodiment includes a so-called computer device, and includes a computer main body H1, a display H2, input devices such as a keyboard H3 and a mouse H4, an HD drive (hard disk drive) (not shown), and the like. ing.
The biological information acquisition apparatus S of the first embodiment is configured by the bed 1, the microwave radar SN1, the client personal computer PCa, and the like.

(Description of the control part of Example 1)
FIG. 3 is an explanatory diagram showing functions up to HRV calculation of the biometric information acquisition apparatus according to the first embodiment of the present invention in a block diagram (functional block diagram).
In FIG. 3, the computer main body H1 of the client personal computer PCa has an I / O (input / output interface) that performs input / output of signals with the outside and adjustment of the input / output signal level, programs and data for performing necessary processing, and the like. ROM (read-only memory, recording medium) in which is stored, RAM (random access memory, recording medium) for temporarily storing necessary data and programs, processing according to the program stored in ROM, etc. A CPU (central processing unit), a clock oscillator, and the like are included, and various functions can be realized by executing programs stored in a ROM, a RAM, and the like.
The client personal computer PCa having the above configuration can realize various functions by executing programs stored in a hard disk, a ROM, or the like.

(Signal input element connected to the computer main body H1 of the client personal computer PCa)
In addition to the keyboard H3 and the mouse H4, output signals from the next signal output element SN1 and the like are input to the computer main body H1 of the client personal computer PCa.
SN1: Microwave radar The microwave radar SN1 irradiates the upper surface of the bed 1 with microwaves, receives a reflected wave from the subject, and inputs an output signal corresponding to the received reflected wave to the computer main body H1. . In the first embodiment, the output signal from the microwave radar SN1 is input to the computer main body H1 via the bandpass filter 11, the amplifier circuit 12, and the AD conversion circuit 13. Note that the bandpass filter 11 has components of higher frequency than the normal body movement, respiration, and pulse wave period (60 Hz or more in the first embodiment) and a DC component (0.015 Hz or less) from the output of the microwave radar SN1. It is a filter for removing. The amplifier circuit 12 amplifies the signal from the microwave radar SN1, and the AD converter circuit 13 converts the analog signal of the microwave radar SN1 into a digital signal. Moreover, the microwave radar SN1 of the first embodiment outputs a signal every 10 ms as an example. That is, the sampling frequency of the microwave radar SN1 is set to 100 Hz.

(Description of function of computer main body H1 of client personal computer PCa)
The hard disk drive of the client personal computer PCa stores a basic software (operating system) OS that controls basic operations of the client personal computer PCa, a biometric information acquisition program AP1 as an application program, and other software (not shown).

(Biological information acquisition program AP1)
The biometric information acquisition program AP1 includes the following functional means (program modules).
C1: Signal receiving means The signal receiving means C1 receives a signal from the microwave radar SN1.
C2: Signal History Storage Unit The signal history storage unit C2 stores a history of output signals output from the microwave radar SN1. In the first embodiment, the history of output signals of the I and Q channels of the microwave Doppler sensor 2 is stored. Accordingly, in the first embodiment, in the microwave radar SN1, each of the radars SN1a and SN1b has nine microwave Doppler sensors 2, and the microwave Doppler sensors 2 output the I and Q channels. 2 (number of radars) × 9 (number of Doppler sensors) × 2 (one channel) = 36 types of output signal histories are stored. However, this signal history storage means is not essential for pulse wave extraction. It is only desirable to have this signal history storage means in order to perform signal processing again based on the recorded data.

FIG. 4 is an explanatory diagram of an example of the waveform of the first embodiment, FIG. 4A is an explanatory diagram of a vibration waveform when the pulse wave component is large, FIG. 4B is an explanatory diagram of a respiratory waveform calculated from the waveform of FIG. 4C is an explanatory diagram of a pulse wave waveform calculated from the waveforms of FIGS. 4A and 4B.
FIG. 5 is an explanatory diagram of an example of a waveform different from the waveform of FIG. 4, FIG. 5A is an explanatory diagram of a vibration waveform when the pulse wave component is small, and FIG. 5B is an explanatory diagram of a respiratory waveform calculated from the waveform of FIG. FIGS. 5C and 5C are explanatory diagrams of pulse wave waveforms calculated from the waveforms of FIGS. 5A and 5B.
FIG. 6 is an explanatory diagram of a method of acquiring vibration waveform information according to the first embodiment.

C3: Vibration Waveform Acquisition Unit The vibration waveform acquisition unit C3 acquires a vibration waveform 21 that is a temporal history of vibration detected by the microwave radar SN1. 4A and 5A, the vibration waveform 21 includes not only the pulse wave but also vibration and noise associated with body movement and respiration. The vibration waveform acquisition unit C3 according to the first embodiment acquires two minutes of data (12000 data) as data of the vibration waveform 21 from the history information stored in the signal history storage unit C2. In addition, when the vibration waveform acquisition means C3 of Example 1 acquires the vibration waveform 21 for 2 minutes and performs the calculation of HRV, when processing the next vibration waveform 21, as shown in FIG. In addition, the vibration waveform 21 for two minutes in which the last one minute of the previous vibration waveform 21 overlaps is acquired and processed. In the first embodiment, the processes of the means C3 to C9 are performed on 36 types of vibration waveforms 21 stored in the signal history storage means C2.

C4: Step width storage means The step width storage means C4 is a period for calculating the average of vibration information and stores a step width N that is sufficiently short for the breathing interval (about 5 seconds). The step size storage means C4 of the first embodiment has a third step size of 0.81 [seconds] as an example of the first step size N1 and 0.41 [seconds] as an example of the second step size N2. As an example of the width N3, 0.21 [second] and as an example of the fourth step width N4, 0.11 [second] are stored.

すなわち、実施例１の呼吸波形の演算手段Ｃ５は、１０ｍｓ毎に測定された振動波形２１の振幅値ｘ_ｉに対して、過去ｍ個分のデータから未来ｍ個分のデータの平均を呼吸波形２２の振幅値ｘ_ｊとして演算している。 C5: Respiration Waveform Calculation Unit The respiration waveform calculation unit C5 calculates a respiration waveform 22 that is an average temporal history of vibration based on the step width W and the vibration waveform 21. In the first embodiment, the respiratory waveform is derived using a simple moving average method as an example. Therefore, when the amplitude value of the vibration waveform 21 is x _i , the amplitude value of the respiration waveform 22 is x _j , and the step size N = 2m + 1, x _j is calculated using the following equation (1). Thus, the respiratory waveform 22 is derived.

That is, the arithmetic means C5 respiration waveform of the first embodiment, the amplitude value x _i of the vibration waveform 21, which is measured every 10 ms, the average respiration waveform of future m pieces of data from the past m pieces of data It is calculated as the amplitude value _{x j} of 22.

Note that the respiration waveform calculation means C5 of the first embodiment derives the respiration waveform 22 for each of the first step width N1 to the fourth step width N4. That is, the first respiration waveform 22-1 is calculated from the equation (1) using the first step size N1, and the second respiration from the equation (1) is calculated using the second step size N2. The waveform 22-2 is calculated, the third step N3 is used to calculate the third respiration waveform 22-3 from the equation (1), and the fourth step N4 is used to calculate the equation (1 ) To calculate the fourth respiration waveform 22-4. As an example, when the respiration waveform 22 is calculated from the vibration waveform 21 shown in FIG. 4A using the first step size (0.81 second), the first respiration waveform 22-1 shown in FIG. 4B is calculated. . As an example, when the respiration waveform 22 is calculated from the vibration waveform 21 shown in FIG. 5A using the fourth step size (0.11 seconds), the fourth respiration waveform 22-4 shown in FIG. 5B is calculated. Is done.
Further, in the respiration waveform calculation means C5 of the first embodiment, the respiration waveform 22 is calculated using the simple moving average method, but the present invention is not limited to this. For example, a weighted moving average method can be used. The preset weighting factor if set to W _i, also by calculating the x _j using the following formula (1 '), it is possible to derive a respiratory waveform 22.

C6: Pulse Wave Waveform Calculation Unit The pulse wave waveform calculation unit C6 calculates a pulse wave waveform 23 obtained by subtracting the respiratory waveform 22 from the vibration waveform 21. The pulse wave waveform calculation means C6 of the first embodiment calculates the pulse wave waveform 23 for each of the first step width N1 to the fourth step width N4. That is, the first respiratory waveform 22-1 is subtracted from the vibration waveform 21 to calculate the first pulse waveform 23-1, and the second respiratory waveform 22-2 is subtracted from the vibration waveform 21; The second pulse wave waveform 23-2 is calculated. Further, the third respiratory waveform 22-3 is subtracted from the vibration waveform 21 to calculate the third pulse waveform 23-3, and the fourth respiratory waveform 22-4 is subtracted from the vibration waveform 21, The fourth pulse wave waveform 23-4 is calculated. In FIG. 4, as an example, when the first respiration waveform 22-1 shown in FIG. 4B is subtracted from the vibration waveform 21 shown in FIG. 4A, a first pulse wave waveform 23-1 shown in FIG. 4C is obtained. 5, as an example, the fourth pulse waveform 23-4 shown in FIG. 5C is obtained by subtracting the fourth respiration waveform 22-4 shown in FIG. 5B from the vibration waveform 21 shown in FIG. 5A. .

That is, in the simple moving average method, the vibration waveform is M [i], the body motion waveform is B [i], the respiratory waveform is R [i], the pulse waveform is H [i], and the noise waveform is W. When [i] is set, the moving average waveform is S [i], and the difference waveform is Q [i], the following equations (2) to (4) are established.
M [i] = B [i] + R [i] + H [i] + W [i] (2)
S [i] ≈B [i] + R [i] (3)
Q [i] = M [i] −S [i] ≈H [i] + W [i] (4)
Therefore, the waveform Q [i] calculated by the pulse wave waveform calculation means C6 includes the noise W [i], but a waveform substantially equivalent to the pulse wave waveform H [i] is obtained. The biological information desired to be obtained from the pulse waveform is the heart rate (number of peaks per minute) and the heart rate interval (peak interval), and noise generally has a smaller amplitude than the pulse wave amplitude. Therefore, there is no problem if the peak position can be detected.

FIG. 7 is an explanatory diagram of a period (2 minutes) for determining body movement according to the first embodiment.
C7: Body Movement Period Determination Unit The body movement period determination unit C7 determines whether it is a period in which body movement such as turning over has occurred. In FIG. 7, the body movement period determination means C <b> 7 according to the first embodiment determines whether or not the body movement has occurred every 5 seconds from the pulse waveform 23. The body movement is an extremely large vibration compared to respiration and pulse wave, and the pulse wave waveform 23 is also affected and observed as a large waveform. Therefore, the body movement period determination unit C7 according to the first embodiment has an area (integrated value) of a waveform portion larger than 0 V as an example of the reference value within a period of 5 seconds that is larger than a preset threshold value. In this case, it is determined that the period of 5 seconds is a period in which body movement has occurred. The preset threshold value is set in advance by an experiment or the like. For example, the threshold value is set to 10 times the area of the average waveform portion in a period in which there is no body movement (a period of only respiration or pulse wave). Can be set as FIG. 7 shows a case where there are three body motion sections in the first half and a large number (about 10 times) of body motion sections in the second half in 2 minutes of pulse wave interval calculation. In addition, although determination of the body movement period of Example 1 illustrated the case where the area of a waveform part was used, it is not limited to this, It can also be determined by whether the value of a peak is larger than a threshold value. It is.

C8: Peak Selection Unit The peak selection unit C8 includes a peak candidate extraction unit C8A, a low amplitude candidate exclusion unit C8B, a short interval candidate exclusion unit C8C, and a respiratory effect candidate exclusion unit C8D. . The peak selection means C8 selects a peak candidate (maximum part of the waveform) based on the heartbeat in the pulse waveform 23.

8 is an explanatory diagram of a peak selection method according to the first embodiment, FIG. 8A is an explanatory diagram of a peak extraction method, FIG. 8B is an explanatory diagram of a method of excluding a peak having a small amplitude from a peak candidate, and FIG. 8C is an interval. It is explanatory drawing of the method of excluding a short peak candidate.
C8A: Peak Candidate Extracting Unit The peak candidate extracting unit C8A detects a peak candidate based on the pulse wave waveform 23 calculated by the pulse wave waveform calculating unit C6. In FIG. 8A, the peak candidate extracting means C8A of the first embodiment uses the waveform portion 23 of a value higher than 0V as an example of a preset reference value in the pulse wave waveform 23 (after being above 0V, In the period from 0V to below 0V), the position that becomes the maximum is extracted as the peak candidate 23b.

C8B: Low Amplitude Candidate Exclusion Unit The low amplitude candidate exclusion unit C8B is configured such that, in a plurality of peak candidates 23b detected in the pulse wave waveform 23, the amplitude value of the peak candidate 23b is smaller than a preset threshold value. Are excluded from the peak candidate 23b. In the low amplitude candidate exclusion means C8B of the first embodiment, 1/3 of the average amplitude value of the adjacent peak candidates 23b is set as an example of a preset threshold value. Therefore, as shown in FIG. 8B, in the peak selecting means C8 of the first embodiment, the amplitude value of the peak candidate 23b is the value of the peak candidate 23b on both sides of the plurality of peak candidates 23b detected in the pulse wave waveform 23. If it is smaller than 1/3 of the average of the amplitude values, the peak candidate 23b is excluded from the candidates and a peak is selected. That is, the low amplitude candidate exclusion means C8B excludes a peak whose amplitude is too small because it is not a peak based on the heartbeat but is likely to be disturbance or noise.
The threshold value is not limited to 1/3 of the average amplitude value of the two adjacent peak candidates 23b illustrated. For example, an arbitrary change may be made according to required accuracy, specifications, etc., such as using the average value of the entire peak candidates instead of the average of the peak candidates 23b on both sides as a reference, or using the average of the 10 peak candidates 23b before and after. Is possible. Moreover, it is not limited to 1/3, It can change arbitrarily, such as 1/4 and 1/5.

C8C: Sub-interval candidate excluding means The sub-interval candidate excluding means C8C has a preset time interval between a pair of peak candidates 23b in a plurality of peak candidates 23b detected in the pulse wave waveform 23. If it is smaller than the threshold value, one peak candidate 23b is excluded from the peak candidates based on the interval between the peak candidates different from the set of peak candidates 23b. In the sub-interval candidate excluding means C8C according to the first embodiment, 1/2 as the average of the peak interval between the peak candidates 23b of 10 beats before and after is set as a preset threshold value. Therefore, as shown in FIG. 8C, in the peak selecting means C8 of the first embodiment, the time interval between the pair of peak candidates 23b1 is 1 of the average of the peak intervals between the peak candidates 23b of 10 beats before and after. When smaller than / 2, the peak candidate 23b1 far from the temporal median of the interval between the peak candidates 23b2 on both sides of the pair of peak candidates 23b1 is excluded from the candidates and the peak is selected. That is, the small interval candidate exclusion means C8C excludes a peak whose interval is too narrow because it is not a peak based on a heartbeat but is likely to be a disturbance or noise.
Note that the threshold value and which peak candidate is excluded is not limited to the exemplified configuration. For example, the peak interval can be arbitrarily changed, for example, it is adjacent to both the front and rear sides, or is the average of all peak candidates. In addition, the distance from the peak candidate 23b2 adjacent to the front side in time is not close to or far from the median time, but the peak interval of the whole peak candidate or the side closer to the average value of the previous 10 beats in time Can be left as a peak candidate.

FIG. 9 is an explanatory diagram of the processing for excluding candidates for respiratory effects according to the first embodiment.
C8D: Respiratory Effect Candidate Exclusion Unit The respiratory effect candidate excluding unit C8D has an area S1 surrounded by one waveform portion 23a1 in the pulse waveform 23 that is greater than a preset threshold value, and one waveform portion. When a plurality of peak candidates 23b exist in 23a1, a peak candidate is selected based on the peak interval of a waveform portion different from one waveform portion 23a1. Specifically, the peak candidates other than the peak candidate 23b3 of one waveform portion 23a1 that is closest to the temporal median 31 of the peaks of the adjacent waveform portions 23a2 that are temporally adjacent to one waveform portion 23a1 in time. 23b4 is excluded from the candidates. In the respiratory effect candidate excluding means C8D according to the first embodiment, the preset threshold value is set to twice the average value of the areas S2a and S2b of the front and rear waveform portions 23a. Therefore, the peak selecting means C8 of the first embodiment uses one waveform portion 23a1 for each waveform portion 23a having a value higher than the value of 0V as an example of a preset reference value in the pulse wave waveform 23. When the enclosed area S1 is larger than a preset threshold and there are a plurality of peak candidates 23b in one waveform portion 23a1, adjacent waveforms adjacent to each other in terms of time with respect to one waveform portion 23a1 The peak candidate 23b3 of one waveform portion 23a1 closest to the temporal median 31 between the peaks of the portion 23a2 is selected as a peak. That is, in the respiratory effect candidate exclusion means C8D, the waveform portion 23a1 having a large area S1 has a respiratory waveform (the respiratory amplitude is about 20 times the pulse wave = the amplitude of the pulse wave is about 5% of the respiratory waveform). 23, it is determined that there is a high possibility of appearing in 23, and those other than the peak candidate 23b that is highly likely to be a peak based on a pulse wave are excluded.

In addition, although twice the average area of the adjacent waveform part was illustrated as a threshold value, it is not limited to this. For example, it is possible to set the average area of the waveform portions for 10 beats before and after, instead of the adjacent waveform portions, or the average area of the entire waveform portions. Moreover, it is not limited to 2 times, It is possible to make arbitrary settings, such as 1.5 times or 3 times or more. Further, it is also possible to adopt a configuration in which peak candidates to be excluded are determined based on the condition that the absolute value of the amplitude value is larger than the average of the whole without being based on the area value.
In the first embodiment, the selection method of selecting the peak candidate 23b3 closest to the median time and excluding the other is illustrated, but the present invention is not limited to this. For example, based on the average value of the past 10 heartbeats, one heartbeat time is added to the time (time) of the pulse wave peak before the corresponding area, and the peak candidate closest to the time of the addition result is selected. It is also possible. In addition, it is also possible to select a peak candidate closest to the average interval of all peak candidates excluding the peak candidate of the waveform portion 23a1.

FIG. 10 is an explanatory diagram of a peak interval evaluation method according to the first embodiment, and is an explanatory diagram of a peak selected by excluding a peak candidate in each exclusion process from the pulse wave waveform shown in FIG. 8A.
Therefore, in the peak selection unit C8 of the first embodiment, the peak is selected as shown in FIG. 10 through the processing in each of the exclusion units C8B to C8D with respect to the example of the pulse waveform shown in FIG. 8A.
In the first embodiment, peaks are selected for the four types of pulse wave waveforms 23-1 to 23-4 derived from the single vibration waveform 21 using the step sizes N1 to N4. . Therefore, in the first embodiment in which four types of pulse waveforms are derived for 36 types of vibration waveforms 21, peaks are selected for 144 (= 36 × 4) types of pulse waveforms 23. .

C9: Abnormal Interval Detection Unit The abnormal interval detection unit C9 detects a peak in which the interval between the peaks 23b selected by the peak selection unit C8 is abnormal with respect to the pulse wave waveform 23. The abnormality interval detecting means C9 of the first embodiment has an abnormal interval RRI between the peaks 23b of the first pulse wave waveform 23-1 to the fourth pulse wave waveform 23-4 based on a preset threshold value. The number of certain peak intervals RRI is detected. The abnormal interval detection means C9 of the first embodiment performs processing on the 144 types of pulse wave waveforms 23 described above.
In the first embodiment, when the n-th interval is RRIn and the preset threshold is R1, it is reasonable to satisfy the following expression (5) based on the following expression (5). Otherwise, it is determined as abnormal.
RRIn− (average of past 15 beats of RRIn + average of future 15 beats of RRIn) / 2 ≦ R1 (5)
Equation (5) can also be expressed as the following equation (5 ′).

That is, in the equation (5), when RRIn is not so far apart (fluctuation is small) with respect to the average of before and after (past / future), it is determined to be appropriate, and when the fluctuation is large, it is determined to be abnormal. That is, the pulse wave based on the heartbeat has a small fluctuation, and when the fluctuation is large, it is determined that there is a high possibility that the pulse wave is affected by noise, breathing, and body movement.
Then, the abnormal interval detecting means C9 of the first embodiment counts the number of RRIn determined to be abnormal.
In the first embodiment, for example, the threshold value R1 can be set to R1 = 500 ms for a subject with large fluctuations, and R1 = 300 ms for a subject with small fluctuations. The user of the information acquisition device S can set. The fluctuation threshold R1 is not limited to the configuration illustrated in the embodiment, and can be changed as appropriate according to the design, specifications, and the like, such as the configuration of the apparatus and the required accuracy.

C10: Waveform Selection Unit The waveform selection unit C10 selects the pulse waveform 23 having the smallest number of abnormal RRIn detected by the abnormal interval detection unit C9 as a waveform used for calculating the HRV of the subject. To do. In the first embodiment, the pulse wave waveform 23 having the smallest number of abnormal RRIns (interval abnormality number) is selected from among the 144 types of pulse wave waveforms 23 described above. That is, the first interval abnormality number in the pulse wave waveform 23-1 derived using the first step width N1 and the pulse wave waveform 23-2 derived using the second step width N2. The second number of abnormal intervals, the third number of abnormal intervals in the pulse waveform 23-3 derived using the third step size N3, and the pulse derived using the fourth step size N4. The pulse wave waveform 23 having the smallest number of abnormal intervals is selected from the fourth number of abnormal intervals in the wave waveform 23-4. In the first embodiment, the pulse waveform 23 having the least abnormality among the pulse waveforms 23 derived using the four types of step sizes N1 to N4 with respect to the 36 types of vibration waveforms 21 is the optimum waveform. Choose as. In addition, when there are a plurality of pulse wave waveforms with the smallest number of abnormal RRIns, any waveform can be selected, but as an example, the waveform that first detected the abnormal interval should be adopted. Is possible. This selection of the optimum waveform is performed every minute. In other words, the optimum waveform can be selected in response to the dynamic change of the optimum waveform according to the position and posture of the body on the bed.

C11: Heartbeat Interval Correction Unit The heartbeat interval correction unit C11 performs correction to replace RRIn determined as an abnormal interval by the abnormal interval detection unit C9 with an average value of RRI before and after not abnormal. Further, the heartbeat interval correction unit C11 of the first embodiment corrects the threshold value R1 used in the abnormal interval detection unit C9, that is, learns the so-called threshold value R1. As for learning of the threshold value R1, any conventionally known method can be employed. For example, when the number of RRIn determined to be abnormal is within a preset range, the previous threshold value R1 is used. If the number of abnormalities is too large, the threshold value R1 can be increased by 5 ms as an example, and if the number of abnormalities is too small, the threshold value R1 can be decreased by 5 ms as an example.

C12: Handing over means during body movement period Handing over means C12 during body movement periods is a peak interval that is not a body motion period, in the body motion period determined by the body motion period determination means C7. Process to take over. When the body movement period determined by the body movement period determination unit C7 continues (in the latter half of FIG. 7, for example, 10 body movement intervals are 10 seconds). In the case of continuous), by substituting the peak interval RRI for the previous one minute as the peak interval RRI of the corresponding one-minute period, the peak interval RRI that is not the body movement period is substituted for the peak interval RRI that is not the body movement period. Take over (correct). That is, in Example 1, there is a possibility that the peak interval RRI of the pulse wave waveform 23 may not be accurate due to the influence of body movement during the body movement period. As the RRI data of the body movement period, the RRI data of the immediately preceding period without body movement. Is used.

11 is an explanatory diagram of the peak interval RRI of the first embodiment, FIG. 11A is an explanatory diagram of an example of a vibration waveform, FIG. 11B is an explanatory diagram of a pulse wave waveform derived from the vibration waveform of FIG. 11A, and FIG. It is explanatory drawing of the peak space | interval (RRI space | interval) derived | led-out from the pulse wave waveform of 11B.
C13: Heartbeat interval extraction means The heartbeat interval extraction means C13 extracts the peak interval RRI based on the peak processed by the takeover means C12 during the body movement period. As shown in FIG. 11C, the heartbeat interval extraction means C13 of the first embodiment creates the waveform information 24 of the peak interval RRIn in which each peak interval (heartbeat interval) RRIn is plotted along the time series.

FIG. 12 is an explanatory diagram of a graph obtained by performing fast Fourier transform on the waveform of the peak interval RRI, where the horizontal axis represents frequency and the vertical axis represents power.
FIG. 13 is an explanatory diagram of an example of HRV, FIG. 13A is a graph showing the activity of the parasympathetic nerve, and FIG. 13B is a graph showing the activity of the sympathetic nerve.
C14: HRV calculation means HRV calculation means C14, which is an example of biological information calculation means and is an example of index calculation means, calculates a heart rate fluctuation index (HRV) based on the peak interval RRI of the pulse wave waveform 23. Calculate. In Example 1, as an example of HRV, both the activity of the parasympathetic nerve and the activity of the sympathetic nerve are calculated. In the first embodiment, specifically, a fast Fourier transform (FFT) is performed on the waveform information 24 created by the heartbeat interval extraction means C13 to obtain a power spectrum as shown in FIG. . Then, 0.04 [Hz] to 0.15 [Hz] is set as a low frequency range, 0.15 [Hz] to 0.4 [Hz] is set as a high frequency range, and the area LF of the waveform portion in the low frequency range; The area HF of the waveform portion in the high frequency region is calculated.

It is known that the high frequency area HF is closely related to the activity of the parasympathetic nerve, and LF / HF is known to be deeply related to the activity of the sympathetic nerve. It is also possible to determine a change in the sleep stage (wakefulness, REM sleep, non-REM sleep) of the subject by observing a temporal change in the activity of the sympathetic nerve. Accordingly, the HRV calculating means C14 of the first embodiment calculates the time change of the HF shown in FIG. 13A as the time change of the activity of the parasympathetic nerve, and the LF shown in FIG. 13B as the time change of the activity of the sympathetic nerve. The time change of / HF is calculated. Therefore, as a result, the HRV calculating unit C14 according to the first embodiment calculates the HRV based on the pulse waveform 23 having the least abnormal RRIn in the waveform selecting unit C10.
In the first embodiment, the HRV calculating unit 14 acquires not only the HRV but also the heart rate by counting the number of peaks in the pulse wave waveform 23 for two minutes.

(Description of Flowchart of Example 1)
Next, a flow of biometric information acquisition processing by the biometric information acquisition program AP1 of the client personal computer PCa according to the first embodiment will be described with reference to flowcharts.

(Description of Flowchart of Biometric Information Acquisition Processing of Example 1)
FIG. 14 is a flowchart of biometric information acquisition processing according to the first embodiment.
Processing of each ST (step) in the flowchart of FIG. 14 is performed according to a program stored in the ROM or the like of the control unit. This process is executed in a multitasking manner in parallel with other various processes of the control unit.

The flowchart shown in FIG. 14 is started when the biometric information acquisition program AP1 is started.
In ST1 of FIG. 14, the vibration waveform 21 detected by the microwave radar SN1 is acquired. Then, the process proceeds to ST2.
In ST2, the respiration waveform 22 is calculated for each step size N1 to N4. Then, the process proceeds to ST3.
In ST3, the pulse waveform 23 (23-1 to 23-4) is calculated from the vibration waveform 21 and each respiratory waveform 22 (22-1 to 22-4). Then, the process proceeds to ST4.
In ST4, the body movement period is determined from the integrated value of the pulse waveform 23. Then, the process proceeds to ST5.

In ST5, a peak candidate is extracted from the pulse wave waveform 23. Then, the process proceeds to ST6.
In ST6, a process of excluding a peak candidate having a small amplitude from the candidates is performed. Then, the process proceeds to ST7.
In ST7, a process of excluding a peak candidate having a small heartbeat interval from the candidates is performed. Then, the process proceeds to ST8.
In ST8, processing for excluding from the candidates the peak candidates affected by respiration from the peak candidates is performed. Then, the process proceeds to ST9.
In ST9, the peak of the pulse waveform 23 is selected (determined). Then, the process proceeds to ST10.
In ST10, the pulse waveform 23 having the smallest number of abnormal RRIns is selected as the optimum pulse waveform. That is, the optimum waveform and step sizes N1 to N4 are selected. Then, the process proceeds to ST11.

In ST11, a correction for replacing RRIn determined to be an abnormal interval with an average value of RRI before and after not abnormal and a process for correcting (learning) a threshold R1 of the heartbeat interval are executed. Then, the process proceeds to ST12.
In ST12, in a period in which body motion continues, a process of taking over the heartbeat interval of the previous one minute is executed. Then, the process proceeds to ST13.
In ST13, a heartbeat interval is extracted from the pulse wave waveform 23 selected in ST10. Then, the process proceeds to ST14.
In ST14, the HRV is calculated and the heart rate is calculated. Then, the biometric information acquisition process ends.

(Operation of Example 1)
In the biological information acquisition apparatus S according to the first embodiment having the above-described configuration, the microwave radar SN1 detects vibration associated with the body movement, breathing, and pulse wave of the subject. And the vibration waveform 21 is acquired based on the output signal of microwave radar SN1. A respiration waveform 22 is derived from the vibration waveform 21 by a moving average method, and a pulse wave waveform 23 is derived based on the vibration waveform 21 and the respiration waveform 22. Then, the heartbeat interval RRI is derived from the pulse wave waveform 23, and HRV is derived.

In recent years, the need for daily measurement of sleep and stress levels at home has increased due to increased health awareness. In addition, to the technology of the wakefulness measurement in the automatic driving technology, the wakefulness / sleep discrimination in the elderly care welfare facilities, the sleep stage determination of non-REM sleep / REM sleep, and the long-term vital signs (breathing / heartbeat) monitoring of infants The demand is getting stronger. In order to realize these technologies, it is necessary to measure the subject's physical and mental loads in a non-contact manner and accurately measure the heartbeat interval (synchronized with the pulse wave interval). Random body movements such as irregular limb movements can be countered by excluding the period, but extraction of pulse wave intervals that are not affected by vibrations associated with respiration that has occurred constantly has been a major issue .
Conventional contact-type heart rate measurements include electrocardiogram measurement with electrodes and photoelectric pulse wave sensors with a photoelectric sensor attached to the fingertip. It was not suitable for long-term measurement of delicate elderly people and infants. In addition, the quality of sleep depends on various factors such as mental and physical stress levels, the presence of daytime exercise, and bathing just before going to bed. It is difficult to judge the quality.

  Therefore, in order to ensure good quality sleep, it is desired to measure the sleep depth and sleep cycle quantitatively at home from the day to self-manage. In addition, it is necessary to regularly measure the degree of stress that causes sleep disorders, and for the elderly, care workers to take action to improve quality of life such as life guidance and exercise guidance. Furthermore, it is important to measure the timing of the elderly's excretion assistance at night in elderly care facilities as a service for elderly people who have a deep sleep time, and excretion care (diapers as much as possible during arousal or light sleep) Exchange). This is why a tool that automatically notifies caregivers of the timing of diaper exchange is desired. In automatic driving and dozing detection, when the degree of arousal and sleepiness appear, there is a tendency for the heartbeat interval to increase. This subtle change in the heartbeat interval is extracted and the driver is warned with an alarm.

Here, in the biological information acquisition apparatus S of the first embodiment, the non-contact type microwave radar SN1 is used, and compared to the case of using polysomnography for attaching electrodes to the subject, The burden can be reduced. In particular, in the first embodiment, vibrations are detected by two radars SN1a and SN1b in the chest and abdomen, and each radar SN1a and SN1b has nine microwave Doppler sensors 2. Therefore, compared with the case where vibration is detected by one radar or a case where there is only one microwave Doppler sensor 2, a pulse wave having a larger area can be obtained, and the posture, sleeping position, and turning of the subject can be obtained. Even if the movement is, for example, it is highly possible that the microwave Doppler sensor 2 can cover the position of the arteriole, and it is easy to detect pulse wave vibration from the body surface. Therefore, vibration detection failures are reduced, HRV detection failures are reduced, and detection accuracy can be improved.
Therefore, in Example 1, HRV can be derived using a non-contact type microwave radar SN1 with a small measurement load on the subject without using an electrocardiogram or a photoelectric pulse wave sensor, and sympathetic and parasympathetic nerves can be derived. The activity level of the autonomic nerve that controls the balance can be measured. In addition, since the pulse waveform 23 is derived with high accuracy, discrimination of arousal / sleep as an example of a biological index based on heartbeat, sleep stage determination of non-REM sleep / REM sleep, and improvement of measurement of stress level Can also be expected.

FIG. 15 is an explanatory diagram of a conventional method of calculating a pulse waveform, FIG. 15A is an explanatory diagram of a vibration waveform corresponding to FIG. 5A, and FIG. 15B is obtained by calculating with a step size of 0.8 seconds in FIG. FIG. 15C is an explanatory diagram of a respiratory waveform, and FIG. 15C is an explanatory diagram of a pulse waveform calculated from the vibration waveform of FIG. 15A and the respiratory waveform of FIG. 15B.
In addition, in the biological information acquisition apparatus S according to the first embodiment, the respiratory waveform 22 is derived using four types of step sizes N1 to N4. In the conventional moving average method, the step size is fixed. Therefore, for example, when 0.8 second is used as the step size for the vibration waveform 21 shown in FIGS. 5A and 15A, as shown in FIG. 15B, the respiration waveform is a gentle waveform compared to FIG. 5B. turn into. Therefore, as shown in FIG. 15C, the peak of the obtained pulse wave waveform is less conspicuous than that in FIG. 5C. Therefore, for example, a peak based on the heartbeat is difficult to discriminate like the peak at the left end of the pulse wave waveform of FIG. 15C, or a peak different from the peak based on the heartbeat is likely to be selected, and accuracy is likely to decrease. Similarly, in the case of the vibration waveform of FIG. 4A, when 0.1 second is used as the step size, the pulse waveform (not shown) has a peak similar to the peak of the pulse waveform compared to FIG. 4C. Many appear and it becomes easy to select a peak different from the peak based on the heartbeat, and the accuracy tends to be lowered. That is, the magnitude of the pulse wave signal in the vibration waveform measured according to the position and posture of the body changes, and the optimal step size changes from time to time. In the conventional technology using a specific step size, There was a problem that accuracy was likely to be lowered.

Therefore, in the conventional method in which the step size is fixed, the heartbeat interval cannot be obtained with sufficient accuracy in the case of the waveforms shown in FIGS. 5A and 15A. On the other hand, in the biological information acquisition apparatus S of the first embodiment, the respiration waveform 22 is derived with four types of step widths N1 to N4 for each two-minute vibration waveform 21. Then, the smallest number of abnormal heartbeat intervals RRIn, that is, the optimum combination of the vibration waveform 21 of the microwave Doppler sensor 2 and the step sizes N1 to N4 is selected. In particular, in the first embodiment, the optimum step widths N1 to N4 are selected every minute in response to the step width changing from moment to moment according to the position of the body. Therefore, the heartbeat interval can be detected with higher accuracy and HRV can be detected with higher accuracy than in the prior art in which the step size is fixed.
In the first embodiment, the HRV is obtained from the vibration waveform 21 based on the data for 2 minutes, but since the HRV is overlapped by 1 minute, the HRV is substantially calculated every minute. It corresponds to that. Therefore, the optimal vibration waveform 21 and step sizes N1 to N4 are selected every minute.

Further, in the biological information acquisition apparatus S of the first embodiment, the peak candidate affected by the respiration is excluded by the respiration effect candidate excluding means C8D which has not been performed at the time of deriving the conventional HRV. Therefore, in the conventional method, the heartbeat interval RRI may be derived based on the peak affected by respiration, not based on the heartbeat, which causes a decrease in accuracy. On the other hand, in Example 1, the peak candidate affected by the respiration is excluded by the respiration effect candidate excluding means C8D. Therefore, HRV accuracy can be improved as compared with the conventional method.
Furthermore, in the biological information acquisition apparatus S of Example 1, peak candidates with small amplitudes and peak candidates with too narrow intervals are excluded from the peak candidates. Therefore, the detection accuracy of the heartbeat interval RRI can be improved as compared with the case where such processing is not executed.

(Example of change)
As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various change is performed within the range of the summary of this invention described in the claim. It is possible. Modification examples (H01) to (H012) of the present invention are exemplified below.
(H01) In the above embodiment, the subject is a human, but is not limited to this. For example, the present invention can be applied to other living bodies such as animals.
(H02) In the above-described embodiments, the exemplified specific numerical values are not limited to the exemplified numerical values, and can be appropriately changed according to the design, specifications, and the like. For example, the step widths N1 to N4 are exemplified by four types, but are not limited to four types as long as they are at least two types.

(H03) In the above-described embodiment, the configuration in which the biometric information acquisition program AP1 performs the centralized processing with the single biometric information acquisition apparatus S is illustrated, but the present invention is not limited thereto. For example, all or part of the biometric information acquisition program AP1 may be stored in a plurality of computer devices connected to the network, and distributed processing, that is, a so-called cloud type configuration may be configured via the network.

(H04) In the above-described embodiment, the microwave radar SN1 is supported, that is, attached to the lower surface of the mattress 1b. However, the microwave radar SN1 is not limited to this, and can be incorporated in the mattress 1b. . The microwave radar SN1 is fixedly supported on the lower surface of the mattress 1b. However, the microwave radar SN1 is not limited thereto. For example, the microwave radar SN1 is interposed between the mattress support 1a and the mattress 1b, and between By providing a slider or the like that can move in the direction, it can be configured to be variably set at an arbitrary position. In addition, the microwave radar SN1 is not supported by the bed 1, and can be changed, for example, stored in the sleeping pocket of the subject, sewn on the sleeping suit, or installed on the ceiling above the bed 1. It is.

(H05) In the above-described embodiment, the microwave radar SN1 that irradiates the microwave is illustrated as an example of the detection member. However, the present invention is not limited to this, and the configuration can be changed to any configuration that can detect the vibration of the human body surface. . For example, it is possible to change the wavelength range of the electromagnetic wave to be used. However, when selecting the wavelength region of the electromagnetic wave, if the wavelength region cannot pass through the mattress 1b or the like, an opening for passing the electromagnetic wave is formed in the mattress 1b, or a wavelength region that is legally restricted by the Radio Law is selected. If selected, it is necessary to obtain authorization and permission.
(H06) In the above embodiment, the connection between the microwave radar SN1 and the client personal computer PCa is configured by a wired cable, but is not limited thereto, and may be configured by, for example, wireless communication.

(H07) In the above-described embodiment, it is desirable to perform the peak candidate exclusion process by the respiratory effect candidate exclusion means C8D, but it is also possible to perform a process that is not performed.
(H08) In the above-described embodiment, it is desirable to use four types of step sizes N1 to N4 and perform processing for selecting the optimum waveform and step size, but it is also possible to perform processing that is not performed.
(H09) In the above-described embodiment, the configuration in which the nine microwave Doppler sensors 2 are provided in the radars SN1a and SN1b is illustrated, but the present invention is not limited to this. The number of microwave Doppler sensors 2 can be arbitrarily changed according to the range to be covered. In order to widen the range to be covered, it is desirable to have a configuration having a plurality of microwave Doppler sensors 2, but it is also possible to have only one.

(H010) In the above embodiment, as shown in FIG. 3, it has been described that the signal processing portion is processed in the computer main body H1, but the portion of the biometric information acquisition program AP1 is embedded software or FPGA (field- It can also be realized with a programmable gate array.
(H011) In the above-described embodiment, the configuration in which the vibration waveform 21 is acquired by the microwave radar SN1 is exemplified, but the present invention is not limited to this. For example, it is possible to employ a configuration that can detect vibration based on body movement, breathing, heartbeat, etc. of a subject in a non-contact manner using a piezoelectric sensor, an air pressure sensor, or a water pressure sensor.
(H012) In the above-described embodiment, the configuration in which the respiratory waveform 22 at each step size N1 to N4 is derived from the vibration waveform 21 and the respective pulse waveform 23 is derived is illustrated, but the present invention is not limited to this. For example, the first respiration waveform 22-1 is derived from the vibration waveform 21 using the first step width N1, and after the first pulse wave waveform 23-1 is derived, the second step width N2 is used. It is also possible to calculate the second respiration waveform 22-2 and the second pulse wave waveform 23-2 in the order of derivation,. Alternatively, after calculating up to the first step abnormality number with respect to the first step width N1, it is also possible to calculate the second step abnormality number with respect to the second step width N2, and so on. It is.

2 ... detection member,
21 ... Vibration waveform,
22 ... Respiration waveform,
22-1 ... the first respiratory waveform,
22-2 ... second respiratory waveform,
23 ... Pulse waveform,
23-1 ... First pulse waveform,
23-2 ... second pulse waveform,
23a1 ... one waveform part,
23a2 ... adjacent waveform portion,
23b ... Peak candidate,
23b1 ... a set of peak candidates 23b3, 23b4 ... peak candidates,
AP1 ... biometric information acquisition program,
C3: Vibration waveform acquisition means,
C5: Respiration waveform calculation means,
C6: Pulse wave waveform calculation means,
C8: Peak selection means,
C9: Abnormal interval detection means,
C14: Indicator calculation means,
N ... step size,
N1 ... first step size,
N2 ... second step size,
PCa ... computer,
R1 ... threshold,
S ... biological information acquisition device,
S1: Area surrounded by one waveform portion.

Claims (13)

A detection member that is arranged in a non-contact state to the subject and detects vibration of the surface of the subject,
Vibration waveform acquisition means for acquiring a vibration waveform that is a temporal history of vibration detected by the detection member;
The first respiration, which is a period for calculating the average of vibration information and is a temporal history of the average of vibration based on the first step width sufficiently short with respect to the breathing interval and the vibration waveform. Respiration that calculates a waveform and calculates a second respiratory waveform that is an average temporal history of vibration based on the second step width and the vibration waveform that are different in duration from the first step width. Waveform calculation means,
A pulse waveform that calculates a first pulse waveform obtained by subtracting the first respiratory waveform from the vibration waveform and calculates a second pulse waveform obtained by subtracting the second respiratory waveform from the vibration waveform. Computing means;
Peak selection means for selecting a peak in each pulse wave waveform;
Based on the peak selected by the peak selection means and a preset threshold value, the number of peak intervals in which the interval of each peak of the first pulse wave waveform is abnormal is detected, and based on the threshold value, An abnormal interval detecting means for detecting the number of peak intervals in which the interval of each peak of the second pulse wave waveform is abnormal;
An index calculation means for calculating a heart rate fluctuation index based on a pulse waveform with a small number of abnormal peak intervals;
An apparatus for acquiring biological information, comprising: A detection member that is arranged in a non-contact state to the subject and detects vibration of the surface of the subject,
From the vibration waveform that is a temporal history of vibration detected by the detection member, the first step width and the vibration waveform that are periods in which an average of vibration information is calculated and are short with respect to the breathing interval In the first pulse waveform calculated by subtracting the first respiratory waveform that is the average temporal history of vibrations calculated based on the peak, the peak selected by the peak selection means is preset. Based on a threshold value, a first interval abnormality number in which the interval of each peak of the first pulse wave waveform is abnormal, and a second step width having a period different from the first step width from the vibration waveform, In the second pulse waveform calculated by subtracting the second respiratory waveform that is the average temporal history of the vibration calculated based on the vibration waveform, the peak is selected by the peak selecting means Each of the second pulse wave waveforms based on the peak and the threshold value And detecting a second interval abnormality number having an abnormal peak interval, comparing the first interval abnormality number and the second interval abnormality number, and generating a pulse waveform having a small number of abnormal peak intervals. Based on an index calculating means for calculating a heart rate variability index,
An apparatus for acquiring biological information, comprising: In each pulse waveform, for each waveform portion having a value higher than a preset reference value, the area surrounded by one waveform portion is larger than a preset threshold value and peaks in the one waveform portion. When there are a plurality of candidates, a peak candidate for selecting a peak candidate of the one waveform portion as a peak of the one waveform portion based on a peak interval of a waveform portion different from the one waveform portion. Selection means,
The biological information acquiring apparatus according to claim 1, wherein the biological information acquiring apparatus is provided. A detection member that is arranged in a non-contact state to the subject and detects vibration of the surface of the subject,
Vibration waveform acquisition means for acquiring a vibration waveform that is a temporal history of vibration detected by the detection member;
A respiration waveform that is a period for calculating the average of vibration information and calculates a respiration waveform, which is a temporal history of the average of vibration, based on a step length sufficiently short with respect to a respiration interval and the vibration waveform And a computing means of
A pulse wave waveform calculating means for calculating a pulse waveform obtained by subtracting the respiratory waveform from the vibration waveform;
In the pulse waveform, for each waveform portion having a value higher than a preset reference value, the area surrounded by one waveform portion is larger than a preset threshold value, and a peak appears in the one waveform portion. Peak selection for selecting a peak candidate of the one waveform portion as a peak of the one waveform portion based on a peak interval of a waveform portion different from the one waveform portion when a plurality of candidates exist Means,
An index calculating means for calculating a heart rate fluctuation index based on the peak interval of the pulse wave waveform;
An apparatus for acquiring biological information, comprising: In the plurality of peak candidates detected in the pulse wave waveform, when the amplitude value of the peak candidate is smaller than a preset threshold value, the peak is excluded from the peak candidate and selected. Selection means,
The biological information acquisition apparatus according to claim 1, further comprising: In the plurality of peak candidates detected in the pulse wave waveform, when the time interval between the set of peak candidates is smaller than a preset threshold, the set of peak candidates is The peak selection means for selecting a peak by excluding one peak candidate based on the interval between different peak candidates,
The biological information acquisition apparatus according to claim 1, further comprising: A plurality of the detection members arranged on the surface of the subject,
The biological information acquisition apparatus according to claim 1, comprising: Computer
Vibration waveform acquisition means for acquiring a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with the subject;
The first respiration, which is a period for calculating the average of vibration information and is a temporal history of the average of vibration based on the first step width sufficiently short with respect to the breathing interval and the vibration waveform. Respiration that calculates a waveform and calculates a second respiratory waveform that is an average temporal history of vibration based on the second step width and the vibration waveform that are different in duration from the first step width. Waveform calculation means,
A pulse waveform that calculates a first pulse waveform obtained by subtracting the first respiratory waveform from the vibration waveform and calculates a second pulse waveform obtained by subtracting the second respiratory waveform from the vibration waveform. Computing means,
Peak selection means for selecting a peak in each pulse wave waveform,
Based on the peak selected by the peak selection means and a preset threshold value, the number of peak intervals in which the interval of each peak of the first pulse wave waveform is abnormal is detected, and based on the threshold value, An abnormal interval detection means for detecting the number of peak intervals in which the interval between the peaks of the second pulse wave waveform is abnormal,
An index calculating means for calculating a heart rate variability index based on a pulse wave waveform with a small number of abnormal peak intervals,
A biometric information acquisition program characterized by being made to function as: Computer
It is a period for calculating the average of vibration information from a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with respect to the subject, and with respect to a breathing interval In the first pulse wave waveform calculated by subtracting the first respiratory waveform that is the average temporal history of vibration calculated based on the first short-term step size and the vibration waveform, Based on a preset threshold value, a first interval abnormality number in which the interval of each peak of the first pulse wave waveform is abnormal, and a second period having a period different from the first step size based on the vibration waveform. In the second pulse waveform calculated by subtracting the second respiratory waveform, which is the average temporal history of vibration calculated based on the step size and the vibration waveform, based on the threshold value A second interval in which the interval between the peaks of the second pulse wave waveform is abnormal The calculation of an index for detecting a constant, comparing the first interval abnormality number and the second interval abnormality number, and calculating a heart rate variability index based on a pulse wave waveform with a small number of abnormal peak intervals means,
A biometric information acquisition program characterized by being made to function as: Computer
Vibration waveform acquisition means for acquiring a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with the subject;
A respiration waveform that is a period for calculating the average of vibration information and calculates a respiration waveform, which is a temporal history of the average of vibration, based on a step length sufficiently short with respect to a respiration interval and the vibration waveform Computing means,
Pulse wave waveform calculation means for calculating a pulse waveform obtained by subtracting the respiratory waveform from the vibration waveform;
In the pulse waveform, for each waveform portion having a value higher than a preset reference value, the area surrounded by one waveform portion is larger than a preset threshold value, and a peak appears in the one waveform portion. When there are a plurality of candidates, the peak candidate of the one waveform portion that is closest to the temporal median value of the peaks of adjacent waveform portions that are adjacent in time to the one waveform portion is Means for selecting a peak to be selected as a peak of one waveform portion;
An index calculating means for calculating a heart rate variability index based on the peak interval of the pulse wave waveform;
A biometric information acquisition program characterized by being made to function as: Obtaining a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with the subject;
The first respiration, which is a period for calculating the average of vibration information and is a temporal history of the average of vibration based on the first step width sufficiently short with respect to the breathing interval and the vibration waveform. A step of calculating a waveform and calculating a second respiratory waveform, which is an average temporal history of vibration, based on the second step width and the vibration waveform having a period different from the first step width. When,
Calculating a first pulse waveform obtained by subtracting the first respiratory waveform from the vibration waveform, and calculating a second pulse waveform obtained by subtracting the second respiratory waveform from the vibration waveform;
Selecting a peak in each pulse wave waveform;
Based on the peak selected in the peak selection step and a preset threshold, the number of peak intervals in which the interval of each peak of the first pulse wave waveform is abnormal is detected, and based on the threshold Detecting the number of peak intervals in which the interval between the peaks of the second pulse wave waveform is abnormal;
Calculating a heart rate variability index based on a pulse waveform with a small number of abnormal peak intervals;
To obtain biological information.   It is a period for calculating the average of vibration information from a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with respect to the subject, and with respect to a breathing interval In the first pulse wave waveform calculated by subtracting the first respiratory waveform that is the average temporal history of vibration calculated based on the first short-term step size and the vibration waveform, Based on a preset threshold value, a first interval abnormality number in which the interval of each peak of the first pulse wave waveform is abnormal, and a second period having a period different from the first step size based on the vibration waveform. In the second pulse waveform calculated by subtracting the second respiratory waveform, which is the average temporal history of vibration calculated based on the step size and the vibration waveform, based on the threshold value A second interval in which the interval between the peaks of the second pulse wave waveform is abnormal A constant number is detected, the first interval abnormality number and the second interval abnormality number are compared, and a heart rate fluctuation index is calculated based on a pulse wave waveform with a small number of abnormal peak intervals. A method for acquiring biometric information. Obtaining a vibration waveform that is a temporal history of vibration of the surface of the subject detected by a detection member arranged in a non-contact state with the subject;
A step of calculating a respiratory waveform that is a period for calculating an average of vibration information and is based on the vibration waveform and a step length sufficiently short with respect to a breathing interval and the vibration waveform. ,
Calculating a pulse waveform obtained by subtracting the respiratory waveform from the vibration waveform;
In the pulse waveform, for each waveform portion having a value higher than a preset reference value, the area surrounded by one waveform portion is larger than a preset threshold value, and a peak appears in the one waveform portion. When there are a plurality of candidates, the peak candidate of the one waveform portion that is closest to the temporal median value of the peaks of adjacent waveform portions that are adjacent in time to the one waveform portion is Selecting as a peak of one waveform portion;
Calculating a heart rate variability index based on the peak interval of the pulse wave waveform;
To obtain biological information.

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