JP5637583B2 - Age estimation device, age estimation method and age estimation program by non-contact biological information collection - Google Patents

Description

  The present invention relates to an age estimation device, an age estimation method, and an age estimation program based on collection of non-contact biological information.

  In the medical field, biological information such as heartbeat, respiration, body temperature, blood pressure, and the like is called vital signs, and the physical characteristics and conditions of the subject are accurately reflected in these biological information. Such biometric information is used, for example, as an index for increasing the safety and comfort in driving a vehicle by knowing the mental state (whether it is in tension, etc.) of the driver when driving the vehicle.

  In particular, heart rate and breathing have been collected by many researchers in the past due to the ease of collection, and research is used as an indicator for detecting the driver's drinking and sleeping states and their signs. Is underway.

  As for the heart rate and respiration rate of a human body, a contact-type measurement method in which electrodes are attached to the chest and a weak current flowing through the human body with heartbeat and respiration is detected is widely used in medical institutions and the like. In addition, methods for measuring heart rate and respiration rate in a non-contact manner using an air mattress or microwave have been developed.

  By the way, collision safety devices such as seat belts and airbags contribute to minimizing the damage caused by automobile traffic accidents, but these safety devices are now independent of the age and gender of passengers. Being activated.

  However, it has been found that the impact resistance of passengers varies depending on age and gender, and it has been reported that elderly people are more likely to be severer than other age groups even if they receive the same external force. . Therefore, if the age and sex of the occupant can be determined and the safety device can be operated according to the age and sex when a traffic accident occurs, it is considered that the occurrence and magnitude of injury to the occupant can be reduced.

  Therefore, an object of the present invention is to provide an age estimation apparatus, an age estimation method, and an age estimation program for estimating the age of a subject from heartbeats and breaths obtained by a biological information collection means.

  One aspect of the present invention is an age estimation apparatus that estimates the age of a subject, obtains biological information including a heartbeat signal from the subject, and obtains an RR interval indicating the heartbeat interval based on the heartbeat signal. The age of the subject is estimated from the RR interval.

  Another aspect of the present invention is an age estimation method for estimating the age of a subject, obtaining biological information including a heartbeat signal from the subject, and indicating a heartbeat interval based on the heartbeat signal. And the age of the subject is estimated from the RR interval.

  According to another aspect of the present invention, there is provided an age estimation program for estimating the age of a subject, wherein biological information including a heartbeat signal is obtained from the subject and a heartbeat interval is determined based on the heartbeat signal. An RR interval is obtained, and a process of estimating the age of the subject from the RR interval is executed.

  Here, biological information acquisition means for acquiring the biological information from the subject, heart rate extraction means for extracting the heartbeat signal from the biological information, RR interval calculation means for obtaining an RR interval from the heartbeat signal, Respiratory fluctuation extracting means for obtaining the respiratory fluctuation of the RR interval calculated by the RR interval calculating means, amplitude value calculating means for obtaining the amplitude value of the respiratory fluctuation, and the subject based on the amplitude value of the respiratory fluctuation It is preferable to include age estimation means for estimating the age.

  Furthermore, it is preferable that the age estimation means determine that the subject is an elderly person when the amplitude value of the respiratory change is equal to or less than a predetermined threshold value.

  In addition, the age estimating means may determine the subject from the amplitude value of the respiratory change in the RR interval determined by the respiratory change extracting means based on a predetermined relational expression between the amplitude value of the respiratory change and the age. It is preferable to estimate the age.

  A biological information acquisition unit that acquires the biological information from the subject; a heart rate extraction unit that extracts the heartbeat signal from the biological information; an RR interval calculation unit that obtains an RR interval from the heartbeat signal; and the RR Respiratory fluctuation extracting means for obtaining respiratory fluctuations of the RR interval calculated by the interval calculating means; integral value calculating means for obtaining an integrated value of the respiratory fluctuations; and It is preferable to include age estimation means for estimating the age.

  Furthermore, it is preferable that the age estimation means determines that the subject is an elderly person when the integrated value of the respiratory change is equal to or less than a predetermined threshold.

  Further, it is preferable that the biological information acquisition means acquires the biological information from the subject without contact. For example, the biological information acquisition unit is preferably a microwave Doppler module.

  Here, it is preferable that the microwave Doppler module is disposed in a backrest portion of a seat. For example, it is preferable to arrange the seat back portion of a vehicle such as an automobile. Furthermore, it is preferable that the microwave Doppler module is disposed at a position shifted to the right from the center when viewed from the front of the seating surface of the seat.

  Further, it is preferable that the heartbeat extracting unit extracts a frequency component of 0.8 Hz to 2.0 Hz as the heartbeat signal from the biological information.

  According to the present invention, the age of the subject can be estimated from the heartbeat and respiration obtained by the biological information collecting means.

It is a figure which shows the basic composition of the age estimation apparatus in embodiment of this invention. It is a figure which shows arrangement | positioning to the sheet | seat of the measurement part in embodiment of this invention. It is a figure which shows the example of a heartbeat waveform. It is a figure which shows the structure of the age estimation part in embodiment of this invention. It is a flowchart of the age estimation process in embodiment of this invention. It is a functional block diagram which shows the structure of the age estimation apparatus in embodiment of this invention. It is a figure which shows the example of the body surface displacement signal obtained in embodiment of this invention. It is a figure which shows the example of the electrocardiogram obtained in embodiment of this invention. It is a figure which shows the example of the spectrum of the body surface displacement signal in embodiment of this invention. It is a figure which shows the example of the spectrum of the electrocardiogram in embodiment of this invention. It is a figure which shows the relationship between the amplitude value of respiratory change, and a test subject's age. It is a figure which shows the relationship between the amplitude value of respiratory change, and a test subject's age. It is a flowchart of the age estimation process in another embodiment of the present invention. It is a functional block diagram which shows the structure of the age estimation apparatus in another embodiment of this invention.

  The age estimation device according to the embodiment of the present invention includes a measurement unit 10 and an age estimation unit 12 as shown in FIG.

  The measurement unit 10 includes means for collecting biological information from a person (subject) that is an age estimation target. The measurement part 10 should just collect the signal which shows a person's heartbeat at least.

  The measurement part 10 can be comprised including a microwave Doppler module, for example. Microwaves have the property that a reflected wave is generated when they hit an object (a person or an object). When the object is moving when the reflected wave is generated, the frequency of the reflected wave is affected and the frequency of the original microwave is shifted. The microwave Doppler module includes a transmitter that emits microwaves, a receiver that receives microwaves reflected by the object, and a calculation unit that detects the difference in frequency between the transmitted wave and the received wave and obtains the movement of the object Consists of including.

  By using this microwave Doppler module to irradiate the subject's chest and back with microwaves, it is possible to measure minute displacements on the surface of the living body caused by the subject's heartbeat and respiration. The oscillation frequency of the microwave is preferably, for example, 10.525 GHz (10.52 GHz to 10.53 GHz). In addition, since microwaves are transmitted through clothing, the heart rate and respiration can be measured while the subject is wearing clothing. With this method, the heart rate and respiration can be measured in a non-restraining and non-invasive manner for the subject.

  The body surface displacement measurement by the microwave Doppler module may be performed from the back side of the subject or from the chest side. However, the measurement from the back side has the advantage of being less susceptible to respiration than the measurement from the chest side.

  For example, as shown in FIG. 2, the measurement unit 10 may be disposed in the vehicle seat 14. FIG. 2 is a view of the seat 14 as seen from the front of the seating surface. It is preferable to arrange the measurement unit 10 on the backrest part 14a so that the microwave hits the upper body from the back side of the subject (driver) sitting on the seat 14. In addition, the measurement unit is located at a position shifted to the right from the center (line A) when viewed from the front of the seat surface of the seat of the backrest portion 14a so that the microwave hits the position as close as possible to the heart of the subject (driver) sitting on the seat 14. It is preferable to arrange 10. At this time, it is preferable to provide the measurement unit 10 so that the microwave is radiated from the backrest portion 14 a toward the seating surface direction of the seat 14.

  Further, the displacement due to the heartbeat is smaller than the displacement due to breathing or other body movements, and a filtering process may be performed to extract only the displacement due to the heartbeat. For example, since the detected frequency differs between the heartbeat and the respiration, the heartbeat component and the respiration component can be separated by using a bandpass filter that transmits only each frequency band. This process will be described later.

When the microwave Doppler module is used for collecting biological information, the power density is preferably 1 mW / cm ² or less so as to be safe with respect to side effects on the human body including heat generation.

  In addition, when non-contact property is not required for the age estimation device, a general electrocardiogram may be used as the measurement unit 10. The electrocardiogram is equipped with electrodes (anode and cathode) with two potential differences across the heart on the surface of the human body, and a ground electrode (instant electrode) at one site, and the potential difference between the electrodes is differentially amplified. To collect a signal indicating the heartbeat.

  As shown in FIG. 3, the heartbeat is composed of three types of waveforms called P wave (atrial excitement wave), QRS wave (ventricular excitement wave), and T wave (ventricular excitement recovery wave). Further, the interval between the apexes of the spike-like QRS wave is defined as the RR interval. In the present embodiment, the vertices of the respective waveforms are detected from the signal obtained by the measurement unit 10, and the vertex interval is evaluated as the RR interval.

  As shown in FIG. 4, the age estimation unit 12 can be configured by a general computer including a processing unit 20, a storage unit 22, an input unit 24, and an output unit 26. The age estimation unit 12 may be configured by a logic circuit configured to perform the following age estimation process.

  The processing unit 20 is a part that performs calculations in a computer such as a CPU. The processing unit 20 executes an age estimation program stored in advance in the storage unit 22 and processes the signal obtained by the measurement unit 10 to estimate the age of the subject. The storage unit 22 includes storage means such as a semiconductor memory and a hard disk. The storage unit 22 is appropriately accessible from the processing unit 20, and stores and holds an age estimation program, a signal obtained by the measurement unit 10, parameters necessary for age estimation processing, and the like. The input unit 24 includes character input means such as a keyboard and a pointing device such as a mouse. The input unit 24 may include an interface for connecting to a network or an external device. The input unit 24 is used to input various data and various parameters necessary for performing age estimation processing. The output unit 26 includes a display device such as a display and a printing device such as a printer. The output unit 26 may include an interface for outputting a signal to an external device. The output unit 26 outputs a signal indicating the age of the subject estimated by the age estimation device, or functions as a user interface for inputting various data and various parameters necessary for performing the age estimation process.

  Hereinafter, age estimation processing in the age estimation apparatus will be described with reference to the flowchart of FIG. Moreover, by performing each process in the following processes, the age estimation device functions as each functional block shown in FIG.

  In step S10, the measurement unit 10 acquires a biological information signal including information about the heartbeat of the subject. The process of step S10 corresponds to the biological information acquisition unit 30.

  In the present embodiment, a case where biological information is acquired using a microwave Doppler module will be mainly described. The microwave Doppler module irradiates the subject with the microwave from the measurement unit 10, receives the microwave reflected by the subject, and detects the difference in frequency between the transmitted wave and the received wave, thereby moving the object. It is comprised including the calculating part which calculates | requires.

  By using this microwave Doppler module to irradiate the subject's chest and back with microwaves, it is possible to measure minute displacements on the surface of the living body caused by the subject's heartbeat and respiration. In the present embodiment, the sampling frequency is 200 Hz and the collection time is 5 minutes. However, the present invention is not limited to this, and it is possible to estimate the age even when measuring a shorter time.

  A signal relating to biological information obtained in the measurement unit 10 is sent to the processing unit 20, and the processing unit 20 stores the information in the storage unit 22.

  In step S12, a signal related to the heartbeat is extracted from the biological information obtained in step S10. The process of step S12 corresponds to the heartbeat extracting unit 32.

  FIG. 7 is an example of a body surface displacement signal obtained by the microwave Doppler module. The body surface displacement signal is superimposed with a waveform that rises and falls according to the breathing of the subject. On the other hand, FIG. 8 is an example of a signal obtained by electrocardiogram for the same subject. Although noise is superimposed, a spike-like QRS wave is clearly observed.

  FIG. 9 shows the spectrum of the body surface displacement signal obtained by the microwave Doppler module, and FIG. 10 shows the spectrum of the signal obtained by the electrocardiogram. From the spectrum of FIG. 10, it was found that the human heartbeat signal is distributed in the frequency band of 0.8 Hz to 2.0 Hz, particularly in the frequency band of 1.0 Hz to 1.6 Hz. Also in FIG. 9, a spectrum peak is observed in a frequency band of 0.8 Hz to 2.0 Hz, particularly in a frequency band of 1.0 Hz to 1.6 Hz.

  Accordingly, when the body surface displacement signal of the subject is obtained by the microwave Doppler module, the processing unit 20 extracts a frequency component in a frequency band of 0.8 Hz to 2.0 Hz by filtering. In particular, it is preferable to extract frequencies in the frequency band of 1.0 Hz to 1.6 Hz. For example, using a third-order Butterworth band filter, the low-pass filter coefficient is set to a low cutoff frequency of 1.0 (Hz) and the high-pass filter coefficient is set to a high cutoff frequency of 1.6 (Hz). Thus, a desired frequency component can be extracted.

  Further, when the heartbeat signal of the subject is obtained by an electrocardiogram, the processing unit 20 preferably performs a process of enhancing the QRS wave by a filter process. For example, using a third-order Butterworth band filter, the low-pass filter coefficient is set to a low cutoff frequency of 5.0 (Hz), and the high-pass filter coefficient is set to a high cutoff frequency of 15.0 (Hz). Thus, the frequency component of the QRS wave can be emphasized.

  The processing unit 20 stores the heartbeat signal component extracted from the body surface displacement signal obtained by the microwave Doppler module or the heartbeat signal in which the QRS wave of the electrocardiogram is emphasized in the storage unit 22.

  In step S14, the RR interval is calculated from the signal indicating the heartbeat obtained in step S12. The processing in step S14 corresponds to the RR interval calculation means 34.

  The RR interval is the interval between spiked QRS wave peaks. The processing unit 20 sets a threshold value for extracting a QRS wave peak from the heartbeat signal obtained in step S12, and when the threshold value is exceeded, the QRS wave peak is assumed to be an adjacent peak interval as an RR interval. calculate. The processing unit 20 stores the obtained RR interval in the storage unit 22.

  Table 1 shows an example of the calculated RR interval. Table 1 shows the RR interval calculated from the body surface displacement signal obtained by the microwave Doppler module and the RR interval calculated from the heartbeat signal obtained by the electrocardiogram for 10 subjects in their 20s. Yes.

  In step S16, respiratory change is extracted from the RR interval calculated in step S14. Step S <b> 16 corresponds to the respiratory change extraction unit 36.

  First, the RR interval calculated in step S14 is sampled at a predetermined sampling period. The sampling frequency is preferably 2 Hz, for example.

  Next, two types of infinite impulse response filters (IIR) are applied to extract respiratory fluctuations from the sampled RR interval signals. In the first infinite impulse response filter, a frequency band of 0.09 Hz or less is cut off. For example, a low-frequency cutoff frequency of 0.09 Hz is filtered using a Butterworth high-pass filter of order 21. Subsequently, in the second infinite impulse response filter, the frequency band of 0.12 Hz or lower is cut off, and further, the frequency band of 0.4 Hz or higher is cut off. For example, a Butterworth bandpass filter of order 21 is used to perform filtering with a low cutoff frequency of 0.12 Hz and a high cutoff frequency of 0.4 Hz.

  In step S18, the amplitude value is obtained from the respiratory change extracted in step S16. Step S18 corresponds to the amplitude value calculation means 38.

  The variation (dispersion) in the RR interval obtained from the measurement for one subject has characteristics depending on the age. That is, the RR interval variation tends to decrease as the age increases.

The method for extracting the amplitude value of the respiratory fluctuation is to detect a positive peak (mountain) and a negative peak (valley) of the waveform of the respiratory fluctuation waveform extracted in step S16 for one subject, The average value of the positive peak and the average value of the negative peak are obtained, and the difference between the average value of the positive peak and the average value of the negative peak is used as the amplitude value (A _RSA ) of respiratory fluctuation.

The processing unit 20 performs the above processing, and stores the obtained amplitude value A _RSA of the respiratory change in the storage unit 22.

In step S20, the age of the subject is estimated from the respiratory fluctuation amplitude value A _RSA extracted in step S18. Step S20 corresponds to the age estimation means 40.

FIG. 11 is a diagram in which the amplitude values A _RSA of respiratory changes obtained for a plurality of subjects are plotted against age. The amplitude value A _RSA of subjects in their 20s (Group I) is distributed in the range of about 20 to 130, whereas the amplitude value A _RSA of subjects in the 40s and over (Group II) is 0 to 40. Distributed in the range.

Therefore, the processing unit 20 determines a subject having an amplitude value A _RSA of 40 to 60 as a threshold, more preferably an amplitude value A _RSA of 50 as a threshold, and an amplitude value A _RSA equal to or lower than the threshold as an elderly person. .

  In such a process, the subject determined to be an elderly person may include a person who is not an elderly person, but the safety device such as adjusting the tightening strength of the seat belt for the elderly person is controlled for the elderly person. There is no problem if you do.

FIG. 12 is a diagram in which the amplitude values A _RSA of respiratory fluctuations obtained for a plurality of subjects are averaged and plotted for each age group. In FIG. 12, the solid line is a conversion line indicating the tendency of the amplitude value A _RSA of the respiratory fluctuation of the body surface displacement signal obtained by the microwave Doppler module, and the broken line is the respiratory fluctuation of the heartbeat signal obtained by the electrocardiogram. It is the conversion line which shows the tendency of amplitude value _ARSA of. In any measurement method, it can be seen that the amplitude value A _RSA tends to gradually decrease from the 20s to the 60s.

Accordingly, the processing unit 20 applies the amplitude value A _RSA of the subject obtained in step S18 to the conversion line in FIG. 12, and estimates the age of the subject.

  Based on the age of the subject thus estimated, a collision safety device such as a seat belt or an airbag can be activated according to the age when a traffic accident occurs. As a result, for elderly people, the operation of the safety device can be adjusted to reduce the occurrence and magnitude of injury to the occupant.

Instead of the method of obtaining the respiratory fluctuation amplitude value in step S18, the integral value I _RSA of respiratory fluctuation may be calculated by applying Equation (1). | RSA | is the absolute value of the numerical value of the respiratory fluctuation waveform. FIG. 13 and FIG. 14 show a flowchart in this case and a functional block diagram of the age estimation apparatus.

The integrated value I _RSA calculated in this way also has a distribution corresponding to the age group of the subject as in FIG. That is, the integrated value I _RSA of subjects in their 20s is distributed over a wide range, whereas the integrated value I _RSA of subjects in their 40s and over is distributed in a low value range. Therefore, if the integrated value I _RSA is equal to or less than a predetermined threshold value, it can be determined that the elderly person.

  DESCRIPTION OF SYMBOLS 10 Measurement part, 12 Age estimation part, 14 Seat, 14a Backrest part, 20 Processing part, 22 Storage part, 24 Input part, 26 Output part, 30 Biometric information acquisition means, 32 Heart rate extraction means, 34 RR interval calculation means, 36 Respiratory fluctuation extracting means, 38 amplitude value calculating means, 40 age estimating means.

Claims (13)

An age estimation device for estimating the age of a subject,
Biometric information acquisition means for acquiring biometric information from the subject;
A heartbeat extracting means for extracting a heartbeat signal from the biological information;
RR interval calculation means for obtaining an RR interval from the heartbeat signal;
A respiratory fluctuation extracting means for obtaining a respiratory fluctuation of the RR interval calculated by the RR interval calculating means;
An amplitude value calculating means for obtaining an amplitude value of the respiratory change;
Age estimation means for estimating the age of the subject based on the amplitude value of the respiratory variation;
Equipped with a,
The age estimating means calculates the age of the subject from the amplitude value of the respiratory change in the RR interval determined by the respiratory change extracting means based on a predetermined relational expression between the amplitude value of the respiratory change and the age. age estimation apparatus and estimates the. An age estimation device for estimating the age of a subject,
Biometric information acquisition means for acquiring biometric information from the subject;
A heartbeat extracting means for extracting a heartbeat signal from the biological information;
RR interval calculation means for obtaining an RR interval from the heartbeat signal;
A respiratory fluctuation extracting means for obtaining a respiratory fluctuation of the RR interval calculated by the RR interval calculating means;
An integral value calculating means for obtaining an integral value of the respiratory change;
An age estimation means for estimating the age of the subject based on the integrated value of the respiratory variation;
An age estimation device comprising: The age estimation device according to claim 1,
The age estimation means, age estimation apparatus amplitude of the respiratory variation is the subject is less than or equal to a predetermined threshold and wherein the stamp Teisu Rukoto to be elderly. The age estimation device according to claim 2,
The age estimation means, age estimation device integrated value of the respiratory variation is the subject is less than or equal to a predetermined threshold and wherein the stamp Teisu Rukoto to be elderly. The age estimation device according to any one of claims 1 to 4 ,
The biometric information acquisition unit acquires the biometric information from a subject in a non-contact manner. The age estimation device according to claim 5 ,
The age estimation apparatus, wherein the biological information acquisition means is a microwave Doppler module. The age estimation device according to claim 6 ,
The microwave Doppler module is disposed on a backrest portion of a seat. The age estimation device according to claim 7 ,
The age estimation apparatus, wherein the microwave Doppler module is arranged at a position shifted to the right from the center when viewed from the front of the seating surface of the seat. The age estimation device according to any one of claims 1 to 8 , wherein
The age estimation apparatus, wherein the heartbeat extraction means extracts a frequency component of 0.8 Hz to 2.0 Hz as the heartbeat signal from the biological information. An age estimation method for estimating the age of a subject,
A biological information acquisition step of acquiring biological information from the subject;
A heartbeat extraction step of extracting a heartbeat signal from the biological information;
An RR interval calculating step for obtaining an RR interval from the heartbeat signal;
A respiratory variation extracting step for obtaining a respiratory variation of the RR interval calculated in the RR interval calculating step;
An amplitude value calculating step for obtaining an amplitude value of the respiratory change,
And age estimation step of estimating the age of the subject based on the amplitude value of the respiratory variation,
Equipped with a,
In the age estimation step, the age of the subject is determined from the amplitude value of the respiratory change in the RR interval determined in the respiratory change extraction step based on a predetermined relationship between the amplitude value of the respiratory change and the age. age estimation method, characterized in that the estimated. An age estimation method for estimating the age of a subject,
A biological information acquisition step of acquiring biological information from the subject;
A heartbeat extraction step of extracting a heartbeat signal from the biological information;
An RR interval calculating step for obtaining an RR interval from the heartbeat signal;
A respiratory variation extracting step for obtaining a respiratory variation of the RR interval calculated in the RR interval calculating step;
An integral value calculating step for obtaining an integral value of the respiratory change;
An age estimation step of estimating the age of the subject based on the integrated value of the respiratory variation;
An age estimation method comprising: An age estimation program for estimating the age of a subject,
On the computer,
A biological information acquisition step of acquiring biological information from the subject;
A heartbeat extraction step of extracting a heartbeat signal from the biological information;
An RR interval calculating step for obtaining an RR interval from the heartbeat signal;
A respiratory variation extraction step for obtaining a respiratory variation of the RR interval calculated in the RR interval calculation step;
An amplitude value calculating step for obtaining an amplitude value of the respiratory change,
An age estimation step of estimating the age of the subject based on the amplitude value of the respiratory variation;
It was carried out,
In the age estimation step, the age of the subject is determined from the amplitude value of the respiratory variation in the RR interval obtained in the respiratory variation extraction step based on a predetermined relationship between the amplitude value of the respiratory variation and the age. age estimation program, characterized in that the estimate. An age estimation program for estimating the age of a subject,
On the computer,
A biological information acquisition step of acquiring biological information from the subject;
A heartbeat extraction step of extracting a heartbeat signal from the biological information;
An RR interval calculating step for obtaining an RR interval from the heartbeat signal;
A respiratory variation extraction step for obtaining a respiratory variation of the RR interval calculated in the RR interval calculation step;
An integral value calculating step for obtaining an integral value of the respiratory change;
An age estimation step of estimating the age of the subject based on the integrated value of the respiratory variation;
An age estimation program characterized by having

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