JP2017000649A - Brain wave analysis method and analysis device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To analyze a psychological state even under a kinetic environment such as during vehicle travel.SOLUTION: The invention is configured to utilize efficiently an electrocardiographic signal in addition to a brain wave signal, for determining a psychological state of an analysis object person. Namely, the invention is based on the knowledge that the electrocardiographic signal is superposed to the brain wave signal with a time delay through blood stream, and ease of flow of the blood stream to a brain from a heart which determines the transmission speed of the electrocardiographic signal to the brain, have correlation with a psychological state of a driver (especially, tension degree). In detail, a time difference between the acquired brain wave signal and the electrocardiographic signal is calculated, then according to the calculated time difference, the psychological state of the analysis object person (for example, a driver J) is determined. A signal corresponding to the electrocardiographic signal may be extracted from the brain wave signals on the plural portions, and thereby the time difference may be acquired based on the extracted signal and the brain wave signal.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electroencephalogram analysis method and an analysis apparatus.

  In order to analyze a human psychological state or the like, an electroencephalogram (electroencephalogram signal) is used. In fact, in the electroencephalogram signals, signals accompanying eye movements and heart movements appear as noise. For this reason, Patent Document 1 discloses a technique for removing noise associated with eye movement and heart movement from an electroencephalogram signal.

JP 2014-533589 A

  By the way, the acquisition of an electroencephalogram signal is generally performed in a quiet and stable environment (static environment) so that noise is not mixed as much as possible, as represented by hospitals and laboratories. On the other hand, recently, it is desired to determine a psychological state using an electroencephalogram signal not only in a static environment but also in a dynamic environment. For example, it is possible to analyze (determine) what kind of psychological state a driver of a vehicle represented by an automobile is, for example, how much the driver's tension is, It has become desirable to analyze the psychological state of pedestrians.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electroencephalogram analysis method and analysis apparatus that can analyze the psychological state of an analysis subject even in a dynamic environment. It is to provide.

  In order to achieve the above object, in the present invention, basically, in addition to an electroencephalogram signal, an electrocardiogram signal that has conventionally been considered only as noise is also effectively used to analyze the psychological state of the subject to be analyzed. Is determined. That is, the present invention relates to the flow of blood flow from the heart to the brain in which the electrocardiogram signal is superimposed on the electroencephalogram signal with a time delay through the blood flow and the transmission speed of the electrocardiogram signal to the brain is determined. This is based on the knowledge that ease and the driver's psychological state (particularly the degree of tension) have a correlation.

Specifically, in the electroencephalogram analysis method of the present invention, the following first solution is adopted. That is, as described in claim 1,
A first step of acquiring an electroencephalogram signal emitted by the analysis subject;
A second step of acquiring an electrocardiogram signal emitted by the analysis subject;
A third step of calculating a time difference between the electroencephalogram signal obtained in the first step and the electrocardiogram signal obtained in the second step;
A fourth step of determining the psychological state of the analysis subject according to the time difference obtained in the third step;
It is supposed to be equipped with.

  According to the above solution, the psychological state of the analysis subject can be determined using the time difference between the electroencephalogram signal and the electrocardiogram signal as a parameter. In particular, in order to obtain the above time difference, it is only necessary to detect the appearance timing of a waveform (for example, a peak waveform) that changes in the same period as that of the electrocardiogram signal for the electroencephalogram signal. Even in a dynamic environment, the time difference can be accurately acquired and the psychological state can be accurately determined.

Preferred embodiments based on the above solution are as described in claims 2 to 4 in the claims. That is,
The electroencephalogram signal acquired in the first step is an electroencephalogram signal at a position corresponding to the occipital region of the analysis subject,
The psychological state of the analysis subject determined in the fourth step is a degree of tension.
(Corresponding to claim 2). In this case, the electroencephalogram signal obtained from the back of the head is a portion where a so-called alpha wave appears, and shows a tension state (in other words, a relaxed state), which is extremely preferable for determining the degree of tension of the analysis subject. It will be a thing.

  In the fourth step, the psychological state obtained by the third step is collated with a database in which the psychological state is associated with the time difference between the electroencephalogram signal and the electrocardiogram signal to store the psychological state. It is determined (corresponding to claim 3). In this case, it is preferable to determine the degree of tension easily (easy) using a database in which the time difference and the degree of tension are associated with each other.

  The analysis subject is assumed to be a driver of the vehicle (corresponding to claim 4). In this case, the degree of tension of the driver of the vehicle can be determined. In particular, when applied to a commercially available vehicle, according to the driver's degree of tension, for example, if the degree of tension is too high, information that prompts a break or the temperature of the conditioned air is reduced. If the change can be made and the degree of tension is too low, change the vehicle state, such as changing the reaction force of the steering handle, etc. This is preferable in terms of preventing the person from being overly relaxed and indiscreet. In addition, when the vehicle manufacturer uses it, for example, when the same driving operation is performed, the behavior of the vehicle is set so that the degree of tension increases in the case of a sports vehicle. In the family car, it is preferable for use in the development of the vehicle such as setting the vehicle behavior characteristic so that the degree of tension is not so high.

In order to achieve the above object, the following second solution is adopted in the electroencephalogram analysis method of the present invention. That is, as described in claim 5,
An eleventh step of acquiring a plurality of electroencephalogram signals emitted by the analysis subject;
Based on the plurality of electroencephalogram signals obtained in the eleventh step, a twelfth step of extracting a time-series repetitively changing signal as an electrocardiogram signal;
A thirteenth step of calculating a time difference between the electroencephalogram signal obtained in the eleventh step and the electrocardiogram signal obtained in the twelfth step;
A 14th step of determining a psychological state of the analysis subject according to the time difference obtained in the 13th step;
It is supposed to be equipped with. According to the above solution, the psychological state of the analysis subject can be determined as in the case of claim 1 without using an electrocardiogram signal separately.

In order to achieve the above object, the following first solution is adopted in the electroencephalogram analysis apparatus of the present invention. That is, as described in claim 6,
An electroencephalogram measurement means for acquiring an electroencephalogram signal emitted by the person to be analyzed;
An electrocardiogram measuring means for acquiring an electrocardiographic signal emitted by the subject to be analyzed;
Difference calculating means for calculating a time difference between the electroencephalogram signal obtained by the electroencephalogram measurement means and the electrocardiogram signal obtained by the electrocardiogram measurement means;
In accordance with the time difference obtained by the difference calculation means, determination means for determining the psychological state of the analysis target person;
It is supposed to be equipped with. According to the above solution, an analyzer for performing the analysis method according to claim 1 is provided.

In order to achieve the above object, the following second solution is adopted in the electroencephalogram analysis apparatus of the present invention. That is, as described in claim 7,
An electroencephalogram measuring means for acquiring electroencephalogram signals at a plurality of locations emitted by the analysis subject;
Based on a plurality of electroencephalogram signals obtained by the electroencephalogram measurement means, an electrocardiogram signal extraction means for extracting a time-series repetitive signal as an electrocardiogram signal;
A difference calculation means for calculating a time difference between the electroencephalogram signal obtained by the electroencephalogram measurement means and the electrocardiogram signal obtained by the electrocardiogram signal extraction means;
In accordance with the time difference obtained by the difference calculation means, determination means for determining the psychological state of the analysis target person;
It is supposed to be equipped with. According to the above solution, an analysis apparatus for executing the analysis method according to claim 5 is provided.

  According to the present invention, it is possible to analyze the psychological state of an analysis subject even under a dynamic environment.

The simplified side view which shows a state when analyzing a driver's psychological state by this invention The figure which shows the position which measures an electroencephalogram. The figure which shows the relationship between the electroencephalogram signal and electrocardiogram signal in a stop. The figure which shows the relationship between the electroencephalogram signal and electrocardiogram signal during driving | running | working at 20 km / h. The figure which shows the relationship between the electroencephalogram signal and electrocardiogram signal during driving | running | working at 60 km / h. The figure which shows collectively the time difference of the electroencephalogram signal and electrocardiogram signal in FIGS. The figure which showed the example of the control system of this invention in the block diagram. The flowchart which shows the example of control of this invention. The flowchart which shows another example of control of this invention.

  In the vehicle V shown in FIG. 1, SS is a driver's seat, and J is a driver as an analysis subject seated in the driver's seat SS. Further, 1 is a steering handle, 2 is an instrument panel, and 3 is a front window glass.

  The driver J is equipped with a helmet-type electroencephalograph 10 for measuring an electroencephalogram on his head. Although not directly related to the present invention, the electroencephalogram measuring instrument 10 is provided with a pair of left and right eye cameras 11 for imaging the movement of the eyeball of the driver J. The driver's seat SS is equipped with an electrocardiograph 12 at a position corresponding to the driver J's heart. The electrocardiograph 12 is, for example, a capacitance type and can be configured by a sheet-embedded heart rate monitor.

  FIG. 2 shows an example of position setting of a large number of electrodes 10a mounted on the above-described electroencephalogram measuring instrument 10. In the embodiment, a total of 32 electrodes 10 a are provided including the GRAND electrode indicated by “GND” and the Reference electrode indicated by “Cpz”.

  Here, in FIGS. 3 to 5, the solid line indicates an example of an electroencephalogram signal obtained from the occipital region (electrode 10 a indicated by “Poz” in FIG. 2) among the electroencephalogram signals obtained by the electroencephalograph 10. It contains noise of ECG signal. 3-5, the broken line shows an example of the electrocardiogram signal obtained by the electrocardiograph 12. FIG. 3 is measurement data acquired when the vehicle is resting while the vehicle is stopped, FIG. 4 is measurement data acquired while traveling at a speed of 20 km / h on the circuit, and FIG. Measurement data acquired during traveling at / h.

  In FIG. 3, there is a time difference between the appearance times of the peak waveforms that change in the same cycle as the electroencephalogram signal and the electrocardiogram signal. In other words, since the electrocardiogram signal is mixed as noise in the electroencephalogram signal in the same cycle as the electrocardiogram signal cycle, the electroencephalogram signal appears at the same cycle as the electrocardiogram signal cycle. The time difference can be acquired by detecting the appearance timing of a waveform to be performed (for example, a peak waveform or a waveform in the vicinity thereof).

  In the case of FIG. 3 where the degree of tension is relatively low, the time difference is large, in FIG. 4, the time difference is small, and in FIG. 5, the time difference is the smallest. FIG. 6 collectively shows the time differences in FIGS.

  The electrocardiographic signal is superimposed as noise on the electroencephalogram signal with a time difference according to the speed of blood flow flowing from the heart to the brain. And it is considered that as the traveling speed increases, tension increases, blood vessels between the heart and the brain become thinner, blood flow speed increases, and the time difference becomes smaller. That is, it can be determined that the smaller the time difference, the faster the blood flow velocity and the higher the degree of tension.

  In addition, the electrocardiogram signal is mixed with the electroencephalogram signal as noise. The situation is that the thickness of the blood vessel slightly changes due to the wave when the blood is sent out from the heart, and the surrounding brain cell compression due to this change in the blood vessel thickness It is considered that the signal was converted into an electric signal and mixed into the electric signal due to brain cell activity.

  The time difference between the electroencephalogram signal and the electrocardiogram signal is created and stored in advance as a database in association with the degree of tension. Thereby, the tension | tensile_strength used as a driver | operator's present psychological state can be determined by collating the said time difference measured this time with a database.

  FIG. 7 is a control block diagram for determining a driver's psychological state using an electroencephalogram signal and an electrocardiogram signal. In FIG. 7, the electroencephalogram signal from the electroencephalograph 10 and the electrocardiogram signal from the electrocardiograph 12 are input to the difference calculation unit 21 in the controller U. In the difference calculation unit 21, the time difference between the above-described electroencephalogram signal and electrocardiogram signal is calculated. The time difference calculated by the difference calculation unit 21 is input to the tension degree determination unit 22. The tension degree determination unit 22 compares the time difference calculated by the difference calculation unit 21 with a database unit (storage unit) 23 that stores the time difference and the tension degree in association with each other, and determines the degree of tension.

  The determination result in the tension degree determination unit 22 is input to the feedback control unit 24. The feedback control unit 24 changes and controls the vehicle state so that the driver J enters an appropriate tension state according to the determined degree of tension. For example, the vehicle state change control can be performed as follows. When the degree of tension is extremely high, it is desirable to relieve tension, so music can be played (may be a display that encourages music to flow), the temperature of the conditioned air can be lowered, It can be increased. In addition, when the degree of tension is too low (a state of randomness), in order to increase the tension of the driver J, for example, the steering force of the driving operation system such as the steering handle 1, the accelerator pedal, the brake pedal, and the clutch pedal is large. The direction is changed, or the side window glass is slightly opened to take in the driving wind. When the degree of tension is moderate, the vehicle state remains unchanged and remains unchanged. Note that the change in the vehicle state is merely an example, and other appropriate methods such as prompting the driver to operate in a direction in which the degree of tension is moderate by voice or display can be adopted.

  FIG. 8 is a flowchart showing an example of control by the controller U described above, and this flowchart will be described below. In the following description, Q indicates a step. First, an electroencephalogram signal from the electroencephalogram measuring instrument 10 is inputted at Q1, and then an electrocardiogram signal from the electrocardiograph measuring instrument 12 is inputted at Q2. Thereafter, in Q3, the time difference between the electroencephalogram signal and the electrocardiogram signal is calculated.

  After Q3, in Q4, the degree of tension is determined according to the time difference calculated in Q3 (determination using a database). Thereafter, in Q5, the vehicle state change control is performed according to the degree of tension determined in Q4.

  FIG. 9 shows another control example of the present invention, in which the above-described time difference is obtained only by an electroencephalogram signal without using the electrocardiograph 12 separately. That is, FIG. 9 is executed instead of the processing of Q1 to Q3 in FIG.

  On the premise of the above, first, a plurality of electroencephalogram signals are input in Q11. As the electroencephalogram signals at a plurality of locations, for example, the electroencephalogram signals from the electrode 10a indicated by “Poz”, the electrode 10a indicated by “O1”, and the electrode 10a indicated by “O2” in FIG.

  After Q11, in Q12, by comparing the electroencephalogram signals at a plurality of locations, a signal that changes repeatedly in time series is taken out as a signal corresponding to the electrocardiogram signal. That is, while the electroencephalogram signals at a plurality of locations are different from each other, it can be considered that the electroencephalogram signals are mixed at the same timing in the electroencephalogram signals at the plurality of locations, Since the ECG signal appears at the same timing, the appearance timing of the ECG signal can be known by the above-described processing.

  After Q22, in Q23, a difference, that is, a time difference between the electrocardiogram signal extracted in Q22 and one arbitrary electroencephalogram signal among a plurality of locations is calculated. Thereafter, the processes in FIG. 4 and subsequent steps in FIG. 8 are performed. Note that it is also possible to obtain a plurality of time differences between each electroencephalogram signal and the extracted electrocardiogram signal by using a plurality of electroencephalogram signals used for the calculation of the time difference, and to make the average value of the plurality of time differences the final time difference.

  Although the embodiments have been described above, the present invention is not limited to the embodiments, and appropriate modifications can be made within the scope of the claims. The electroencephalograph 10 may be a non-contact type. It is possible to appropriately select how to use the determined psychological state of the driver. For example, as shown in FIG. 1, analysis (determination) of a driver's psychological state using an electroencephalogram signal and an electrocardiogram signal is not used for a general user (for a commercially available vehicle), but is data by a vehicle manufacturer. It can also be used for collection. That is, for example, a driver's psychological state obtained using an electroencephalogram signal and an electrocardiogram signal is created and stored as a database stored in association with various driving scenes. A database can be installed and used to estimate the psychological state of the driver in a certain driving scene. Further, it can be used only by the vehicle manufacturer in order to help the vehicle design, improvement, etc. so that the driver's psychological state is in a preferable state. In addition, the analysis target person is not limited to a person who operates a vehicle such as an automobile, a railway vehicle, a ship operator, or an airplane operator, but an appropriate person such as a pedestrian can be set as the analysis target person. For example, depending on the influence of the video on the psychological state, gender, age, etc. by showing a certain video set on a game machine etc. to multiple (many) analysts at the same time and determining the psychological state It can be used in appropriate fields, such as analyzing differences in psychological state. Of course, the object of the present invention is not limited to what is explicitly stated, but also implicitly includes providing what is substantially preferred or expressed as an advantage.

  The present invention is preferable in determining the psychological state of the analysis subject under a dynamic environment.

V: Vehicle SS: Driver's seat J: Driver (analysis subject)
U: Controller 10: Electroencephalograph 10a: Electrode 12: Electrocardiograph 21: Difference calculation unit 22: Tension degree determination unit 23: Database 24: Feedback control unit

Claims (7)

A first step of acquiring an electroencephalogram signal emitted by the analysis subject;
A second step of acquiring an electrocardiogram signal emitted by the analysis subject;
A third step of calculating a time difference between the electroencephalogram signal obtained in the first step and the electrocardiogram signal obtained in the second step;
A fourth step of determining the psychological state of the analysis subject according to the time difference obtained in the third step;
A method for analyzing an electroencephalogram, comprising: In claim 1,
The electroencephalogram signal acquired in the first step is an electroencephalogram signal at a position corresponding to the occipital region of the analysis subject,
The psychological state of the analysis subject determined in the fourth step is a degree of tension.
A method for analyzing an electroencephalogram characterized by that. In claim 1 or claim 2,
In the fourth step, the psychological state obtained by the third step is collated with a database in which the psychological state is associated with the time difference between the electroencephalogram signal and the electrocardiogram signal to store the psychological state. A method of analyzing an electroencephalogram characterized by determining. In any one of Claims 1 thru | or 3,
The method for analyzing an electroencephalogram, wherein the subject to be analyzed is a vehicle driver. An eleventh step of acquiring a plurality of electroencephalogram signals emitted by the analysis subject;
Based on the plurality of electroencephalogram signals obtained in the eleventh step, a twelfth step of extracting a time-series repetitively changing signal as an electrocardiogram signal;
A thirteenth step of calculating a time difference between the electroencephalogram signal obtained in the eleventh step and the electrocardiogram signal obtained in the twelfth step;
A 14th step of determining a psychological state of the analysis subject according to the time difference obtained in the 13th step;
A method for analyzing an electroencephalogram, comprising: An electroencephalogram measurement means for acquiring an electroencephalogram signal emitted by the person to be analyzed;
An electrocardiogram measuring means for acquiring an electrocardiographic signal emitted by the subject to be analyzed;
Difference calculating means for calculating a time difference between the electroencephalogram signal obtained by the electroencephalogram measurement means and the electrocardiogram signal obtained by the electrocardiogram measurement means;
In accordance with the time difference obtained by the difference calculation means, determination means for determining the psychological state of the analysis target person;
An electroencephalogram analysis apparatus comprising: An electroencephalogram measuring means for acquiring electroencephalogram signals at a plurality of locations emitted by the analysis subject;
Based on a plurality of electroencephalogram signals obtained by the electroencephalogram measurement means, an electrocardiogram signal extraction means for extracting a time-series repetitive signal as an electrocardiogram signal;
A difference calculation means for calculating a time difference between the electroencephalogram signal obtained by the electroencephalogram measurement means and the electrocardiogram signal obtained by the electrocardiogram signal extraction means;
In accordance with the time difference obtained by the difference calculation means, determination means for determining the psychological state of the analysis target person;
An electroencephalogram analysis apparatus comprising:

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