JP6550952B2 - Method and apparatus for analyzing electroencephalogram - Google Patents

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, in recent years, it has been 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 how pedestrians are in tension.

  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 degree of tension 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 been conventionally considered only as noise is effectively used, and the degree of tension 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 there is a correlation between ease and the driver's degree of tension.

Specifically, in the electroencephalogram analysis method of the present invention, there is adopted a solving techniques such as follows. 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 subject of analysis;
A third step of calculating a time difference in a peak waveform or a waveform in the vicinity thereof between the electroencephalogram signal obtained in the first step and the electrocardiogram signal obtained in the second step;
A fourth step of determining the degree of tension of the person to be analyzed according to the time difference obtained in the third step;
It is supposed to be equipped with.

  According to the above-described solution technique, it is possible to determine the degree of tension of the analysis subject 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 obtained with high accuracy, and the degree of tension can be determined with high accuracy.

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 person to be analyzed (corresponding to claim 2). In this case, the electroencephalogram signal obtained from the back of the head is a place where a so-called alpha wave appears, and it is extremely preferable in determining the degree of tension of the person to be analyzed because it well indicates a tense state (in other words, a relaxed state). It will be a thing.

  In the fourth step, the degree of tension is determined by collating the time difference obtained in the third step with a database that stores the degree of tension associated with the time difference between the electroencephalogram signal and the electrocardiogram signal. Yes, as in (claim 3). In this case, it is preferable to easily (easily) determine the degree of tension 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 case of a family car, it is preferable to set it to the behavior characteristics of the vehicle such that the degree of tension does not increase so much, and so on to help develop the vehicle.

To achieve the above object, in the electroencephalogram analysis apparatus of the present invention are adopted solving techniques such as follows. That is, as described in claim 5 ,
EEG measuring means for acquiring an EEG signal emitted by a person to be analyzed;
An electrocardiogram measurement means for acquiring an electrocardiogram signal emitted by the subject of analysis;
A difference calculation means for calculating a time difference between a peak waveform or a waveform in the vicinity thereof between an electroencephalogram signal obtained by the electroencephalogram measurement means and an electrocardiogram signal obtained by the electrocardiogram measurement means;
A determination unit that determines the degree of tension of the person to be analyzed according to the time difference obtained by the difference calculation unit;
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.

  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 the driver | operator's tension degree 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 a control system of this invention in block diagram. The flowchart which shows the example of control of this invention. The flowchart which shows the example of reference control .

  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. The electroencephalogram measurement device 10 is provided with a pair of left and right eye cameras 11 for capturing the movement of the eyeball of the driver J, though not directly related to the present invention. 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 10a are provided, including GRAND electrodes indicated by "GND" and Reference electrodes 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 the electrocardiogram 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. It is measurement data acquired while driving 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 in which the degree of tension is relatively low, the time difference is large, in the case of FIG. 4 the time difference is small, and in the case of FIG. 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. The higher the traveling speed, the higher the tension, the thinner the blood vessels between the heart and the brain, the higher the blood flow speed, and the smaller the time difference. 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. Thus, by checking the measured current time difference with the database, it is possible to determine the degree of tension at which the driver's current mental state is reached.

  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 electroencephalogram measurement device 10 and the electrocardiogram signal from the electrocardiogram measurement device 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 is in 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. Or the side wind glass is slightly opened to take in the traveling 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 an example of reference control , in which the above-mentioned time difference is obtained only by the electroencephalogram signal without using the electrocardiograph 12 separately. That is, FIG. 9 is executed in place 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, EQ signals at a plurality of locations are compared in Q12 to extract time-series repetitively changing signals as signals 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, the difference, that is, the time difference between the electrocardiogram signal extracted in Q22 and any one electroencephalogram signal of a plurality of locations is calculated. After this, the processing of FIG. 4 and thereafter in FIG. 8 is 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. How to use the determined degree of tension of the driver can be appropriately selected. For example, as shown in FIG. 1, the analysis (determination) of the driver's tension 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 tension degree obtained by 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 how much the driver is nervous in a certain driving scene. Also, it may be used only by the vehicle manufacturer in order to help design, improve, etc. the vehicle so that the driver's degree of tension 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 degree of tension, gender, age, etc., by showing a certain video set on a game machine or the like to a plurality (a large number) of analysis subjects at the same time and determining the degree of tension It can be used in appropriate fields such as analyzing differences in tension levels. Of course, the object of the present invention is not limited to what is explicitly stated, but implicitly also includes providing what is substantially preferred or expressed as an advantage.

  The present invention is preferable in determining the degree of tension of an analysis subject under a dynamic environment.

V: Vehicle SS: Driver's seat J: Driver (analyzer)
U: controller 10: electroencephalograph 10a: electrode 12: electrocardiograph 21: difference calculation unit 22: tension degree determination unit 23: database 24: feedback control unit

Claims (5)

A first step of acquiring an electroencephalogram signal emitted by an analysis subject;
A second step of acquiring an electrocardiogram signal emitted by the subject of analysis;
A third step of calculating a time difference between a peak waveform or a waveform in the vicinity thereof between the electroencephalogram signal obtained in the first step and the electrocardiogram signal obtained in the second step;
A fourth step of determining the degree of tension of the person to be analyzed according to the time difference obtained in the third step;
A method of analyzing an electroencephalogram characterized by comprising: In claim 1,
The electroencephalogram analysis method, wherein the electroencephalogram signal acquired in the first step is an electroencephalogram signal at a position corresponding to the occipital region of the person to be analyzed. In claim 1 or claim 2,
In the fourth step, the degree of tension is determined by collating the time difference obtained in the third step with a stored database in which the degree of tension is associated with the time difference between the electroencephalogram signal and the electrocardiogram signal. EEG analysis method characterized by that. In any one of claims 1 to 3,
A method of analyzing electroencephalograms, wherein the subject of analysis is a driver of a vehicle. EEG measuring means for acquiring an EEG signal emitted by a person to be analyzed;
An electrocardiogram measurement means for acquiring an electrocardiogram signal emitted by the subject of analysis;
A difference calculation means for calculating a time difference between a peak waveform or a waveform in the vicinity thereof between an electroencephalogram signal obtained by the electroencephalogram measurement means and an electrocardiogram signal obtained by the electrocardiogram measurement means;
A determination unit that determines the degree of tension of the person to be analyzed according to the time difference obtained by the difference calculation unit;
An electroencephalogram analyzer characterized by comprising.

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