JP2014230717A - Concentration level estimation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concentration level estimation device capable of estimating a concentration level according to individual differences with a high degree of precision.SOLUTION: A concentration level estimation device 1 for estimating a concentration level of an object person includes: a heartbeat sensor 10 for detecting the information on heartbeats from the object person; a concentration level estimation part 15 for estimating a concentration level from the information on the heartbeats; a collection part 12 for collecting a subjective concentration level correlated with the concentration level by the input of the object person, a reaction time, etc.; a conversion part 13 for converting the subjective concentration level, the reaction time, etc. into a concentration level; and a learning part 14 for learning the heartbeat information corresponding to the input subjective concentration level, the reaction time, etc. and the concentration level converted by the conversion part 13 as learning data. The concentration level estimation part 15 estimates the concentration level from the heartbeat information using the result of the learning at the learning part 14.

Description

  The present invention relates to a concentration estimation apparatus.

  It is known that the degree of human concentration has a deep relationship with brain waves (especially θ waves). However, it is difficult to measure brain waves from people every day. Therefore, a technique has been proposed in which physiological information (such as heartbeat, respiration, and skin potential activity) that correlates with the concentration level is detected and the concentration level is estimated using the physiological information. In Patent Document 1, the degree of concentration is estimated from a plurality of pieces of biological information (such as heart rate, respiration, and skin resistance value) measured from a person, and concentration level rule setting information that associates the pieces of biological information with the concentration state. A concentration level estimation device that displays the estimated concentration level is disclosed.

Japanese Patent Laid-Open No. 9-262216 JP 2008-79737 A JP 2012-63885 A JP 2012-10856 A JP 2011-167323 A

  Since there are individual differences in the degree of concentration, there is room for improvement in estimating the degree of concentration according to individual differences. In the case of the concentration estimation device disclosed in Patent Document 1, the concentration is estimated according to the concentration rule setting information in which a plurality of pieces of biological information are associated with the concentration state. The difference is not reflected.

  Therefore, an object of the present invention is to provide a concentration degree estimation device that can estimate the degree of concentration with high accuracy according to individual differences.

  A concentration level estimation apparatus according to the present invention is a concentration level estimation device for estimating a concentration level of a target person, and includes first information detection means for detecting first information correlated with the concentration level from the target person, A concentration degree estimating means for estimating the degree of concentration from the first information detected by the one information detecting means; a second information collecting means for collecting second information correlated with the concentration degree by the input of the subject; Conversion means for converting the second information collected by the information collection means into a degree of concentration, first information detected by the first information detection means corresponding to the second information collected by the second information collection means, and conversion Learning means for learning the concentration degree converted by the means as learning data, and the concentration degree estimation means estimates the concentration degree from the first information using the learning result of the learning means.

  In this concentration level estimation device, the first information having a correlation with the concentration level is detected from the subject by the first information detection means. Since this first information has a correlation with the degree of concentration of a person, it can be used for estimation of the degree of concentration, for example, physiological information such as heartbeat, respiration, and skin potential activity. In the concentration estimation apparatus, the second information collecting means collects second information correlated with the concentration from the target person. Since this second information is correlated with the degree of concentration by human input, it can be used to personally adapt the relationship between the first information and the degree of concentration. For example, the second information is input by a person. Subjective concentration, reaction time for any task. In the concentration estimation device, the conversion means converts the second information into the concentration, and the learning means learns the first information corresponding to the second information and the concentration converted from the second information as learning data. To do. By this learning, the relationship between the first information and the degree of concentration can be personally adapted. Therefore, in the concentration degree estimation device, the concentration degree is estimated from the first information by using the learning result by the concentration degree estimating means. This estimated degree of concentration reflects the learning result for personal adaptation, and is a degree of concentration according to the individual of the subject person. As described above, the concentration estimation apparatus collects the second information correlated with the concentration input by the target person, and learns the first information and the concentration converted from the second information as learning data. By doing so, the relationship between the first information and the degree of concentration can be personally adapted, and the degree of concentration can be estimated with high accuracy according to individual differences.

  In the concentration level estimation apparatus of the present invention, the conversion unit calculates a variation in the concentration level converted from the second information, and the learning unit learns considering the variation in the concentration level calculated by the conversion unit. Is preferred.

  Since the second information is input by a person, there is variation (error). Therefore, the degree of concentration converted from the second information also varies. Therefore, in the concentration level estimation device, when the conversion unit converts the concentration level from the second information, the concentration level variation is also calculated. In the concentration estimation apparatus, learning is performed by taking into account the variation in the concentration by the learning means. In this way, the concentration estimation apparatus performs learning by taking into account the variation in the second information input by the subject (and thus the variation in the concentration converted from the second information), thereby performing learning. The estimation result of the degree of concentration does not change abruptly, and stable estimation is possible.

  According to the present invention, the second information correlated with the degree of concentration input by the subject is collected, and the first information and the degree of concentration converted from the second information are learned as learning data. The relationship between the first information and the degree of concentration can be personally adapted, and the degree of concentration can be estimated with high accuracy according to individual differences.

It is a block diagram of the concentration estimation apparatus which concerns on this Embodiment. It is a graph which shows the comparative example of the concentration degree (estimated label) estimated from the heartbeat feature-value, and the concentration degree (correct answer label) by the theta wave content rate of an electroencephalogram. It is explanatory drawing of the method of classifying the class label of a concentration degree from (theta) wave content rate. It is a schematic diagram which shows an example of the learning data memorize | stored in the memory | storage part of FIG. It is an example of the display screen for collecting the input information by a user in the collection part of FIG. 1, (a) is a display screen for collecting subjective concentration, and (b) for collecting reaction time It is a display screen. It is an example of the correspondence between the heart rate feature amount measurement section and the collection of input information by the user, (a) is the correspondence relationship between the heart rate feature amount measurement section and the subjective concentration degree collection timing, and (b) is the heart rate feature. This is a correspondence relationship between the quantity measurement section and the reaction time collection section. It is an example of the relationship between the subjective concentration and the reaction time and the θ wave content (concentration), (a) is the relationship between the subjective concentration and the θ wave content, and (b) is the reaction time and the θ wave. It is the relationship with the content rate. It is a figure which shows the dispersion | variation between (theta) wave content rate (concentration degree) and subjective concentration degree. It is an example of the correspondence of the heart rate feature-value measurement area when a user walks, and the subjective concentration degree collection timing by a user.

  Hereinafter, an embodiment of a concentration estimation apparatus according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  The concentration estimation apparatus according to the present embodiment is configured by incorporating a concentration estimation application into a smartphone carried by a user (corresponding to a subject whose concentration is described in the claims). . The concentration level estimation apparatus according to the present embodiment estimates the concentration level of a person without using an electroencephalogram (particularly, a θ wave). In order to estimate the degree of concentration, the concentration degree estimation apparatus according to the present embodiment uses the heartbeat as the first information correlated with the degree of concentration, and is input by the user as the second information correlated with the degree of concentration. Subjective concentration and reaction time of input by the user are used.

  Among human background brain waves, a band of 4 to 8 Hz is called a θ wave, and is known to occur when sleepiness occurs. On the other hand, there is a characteristic brain wave called Fmθ wave measured in the frontal region, and it is known that this Fmθ wave is generated when concentrated on one thing. The present inventor has confirmed a phenomenon in which the θ wave power is significantly increased through the experiment even when the button is pressed, the sentence is created, or the vehicle is driven. This result suggests that the concentration state of a person can be determined from the θ wave content rate or the θ wave power without directly observing the Fmθ wave. Therefore, the degree of concentration can be defined by the θ wave content rate or θ power of the electroencephalogram. However, it is difficult to measure brain waves from people every day.

  Examples of physiological information other than brain waves include heartbeat, respiration, and skin potential activity. Such physiological information can be measured more easily than the electroencephalogram measurement by using a wristwatch type or chest band type device. Therefore, in the present embodiment, the degree of concentration defined by the electroencephalogram is estimated using the heartbeat from the physiological information.

  There are individual differences in the degree of concentration, and the degree of concentration may vary from person to person even when physiological information such as heartbeat is the same. However, there is a case where there is no data for each individual in the relationship between the physiological information and the degree of concentration. Therefore, in order to personally adapt this relationship, learning is performed using the subjective concentration level input by the user having a correlation with the concentration level and the reaction time of the input by the user.

  As this learning, for example, a multi-class classification (particularly, two-class classification) or a regression model is learned by a machine learning technique represented by a support vector machine. This learning uses a basic learning data set obtained from an unspecified large number of people and an additional learning data set obtained from users. The basic learning data is an electroencephalogram when performing a task that concentrates in advance and a task that rests. This is data that simultaneously measures the θ wave content rate (concentration level) and the heart rate feature amount, and sets the concentration level and the heart rate feature amount for which the θ wave content rate is determined as a threshold. The additional learning data collects the subjective concentration level and reaction time input by the user and measures the features of the user's heart rate corresponding to it, and the concentration level and heart rate converted from this subjective concentration level and reaction time. This is data in which feature quantities are set.

  The heartbeat feature amount used in this embodiment will be described. In the present embodiment, a plurality of heartbeat feature amounts are extracted from the electrocardiogram detected by the user. As this extraction method, RR interval (R wave and R wave interval) data is acquired from time series data of cardiac potentials, and a heartbeat feature amount is calculated from the RR interval data for a predetermined time (for example, 3 minutes). As the heartbeat feature amount, four feature amounts of RRV, LF / HF, barycentric frequency, and peak frequency are used. RRV is the variance of the RR interval. LF / HF is obtained by dividing the LF component (0.04 to 0.15 [Hz]) in the power spectrum of the RR interval by the HF component (0.15 to 0.4 [Hz]). The centroid frequency is a frequency indicating the centroid of the power spectrum at the RR interval. The peak frequency is a frequency indicating the maximum value of the power spectrum in the RR interval. In the present embodiment, a vector composed of values of RRV, LF / HF, barycentric frequency, and peak frequency is referred to as a heartbeat feature vector x.

  FIG. 2 shows a comparative example of the degree of concentration estimated from the four heartbeat feature amounts and the concentration degree based on the θ wave content of the electroencephalogram. Here, an electrocardiogram and an electroencephalogram were simultaneously detected from a subject, four heartbeat feature quantities were calculated from the electrocardiogram, and a θ wave content rate was obtained from the electroencephalogram. In the present embodiment, the degree of concentration is determined by two classes of concentration and rest. In the present embodiment, quadratic discriminant analysis (QDA [Quadratic Discriminant Analysis]) is used as a method for discriminating two classes of concentration from the four heartbeat feature quantities. In FIG. 2, the time change G1 of the θ wave content rate is discriminated using the threshold value S, and the case where it is larger than the threshold value S is concentrated, and the case where it is equal to or smaller than the threshold value S is rested. This discrimination result is indicated by a circle as a correct answer label. The threshold value S is appropriately set by experiment or the like. In addition, the degree of concentration estimated from the heartbeat feature amount is indicated by an x mark as an estimation label. When the concentrated correct answer label and the estimated label are compared and the correct answer label of the rest and the estimated label are compared, there are many portions where the correct answer label matches the estimated label. From this result, it can be seen that there is a correlation between the heartbeat and the θ wave content rate (concentration) of the electroencephalogram.

  There are three forms in this embodiment. The first embodiment is a basic form of a concentration degree estimation apparatus. In the second embodiment, learning is performed with emphasis on additional learning data as the amount of additional learning data increases. The third embodiment is a form for increasing the collection rate such as the subjective concentration from the user.

  Now, with reference to FIG. 1, the concentration estimation apparatus 1 according to the first embodiment will be described in detail. FIG. 1 is a configuration diagram of a concentration degree estimation apparatus according to the present embodiment.

  The concentration level estimation device 1 includes a heart rate sensor 10, a storage unit 11, a collection unit 12, a conversion unit 13, a learning unit 14, a concentration level estimation unit 15, and a display unit 16. The memory | storage part 11, the collection part 12, the conversion part 13, the learning part 14, the concentration degree estimation part 15, and the display part 16 are comprised in a smart phone. The heart rate sensor 10 can wirelessly communicate with a smartphone. In the first embodiment, the heart rate sensor 10 corresponds to the first information detection unit described in the claims, the collection unit 12 corresponds to the second information collection unit described in the claims, The conversion unit 13 corresponds to the conversion unit described in the claims, the learning unit 14 corresponds to the learning unit described in the claims, and the concentration degree estimation unit 15 estimates the concentration degree described in the claims. Corresponds to means.

  The heart rate sensor 10 will be described. The heart rate sensor 10 is a sensor that detects a cardiac potential. The heart rate sensor 10 is a chest band type worn on the chest of the user. The heart rate sensor 10 has a wireless communication function such as Bluetooth (registered trademark) for wireless communication with a smartphone. The heart rate sensor 10 always detects the user's cardiac potential and transmits the detected cardiac potential to the smartphone via wireless communication.

  The storage unit 11 will be described. The memory | storage part 11 is comprised in the predetermined area | region of the memory device of a smart phone. The storage unit 11 stores learning data used by the learning unit 14. The learning data includes basic learning data stored in advance in the storage unit 11 and additional learning data stored in the storage unit 11 every time it is collected from the user. The learning data consists of a pair of a heart rate feature vector x (RRV, LF / HF, barycentric frequency, peak frequency) and a concentration degree vector w (rest class probability, concentration class probability).

The basic learning data is learning data acquired from an unspecified number of people before the start of use. A method of creating this basic learning data will be described. In a preliminary experiment, an electroencephalogram and an electrocardiogram are simultaneously detected for a predetermined time from an unspecified number of people. When the θ wave content rate is acquired from the electroencephalogram, the θ wave content rate G2 is determined using the threshold value S as shown in FIG. If it is larger than the threshold value S, the probability of the concentrated class is set to 1, and the probability of the rest class is set to 0. If the threshold is less than or equal to the threshold S, the rest class probability is set to 1 and the concentrated class probability is set to 0. Further, when the RR interval is acquired from the cardiac potential, RRV, LF / HF, barycentric frequency, and peak frequency are calculated from the RR interval. FIG. 4 shows an example of basic learning data x ₁ , x ₂ ,... Stored in the storage unit 11. If the user's own brain wave or electrocardiogram can be detected in advance, the basic learning data of the user may be created and stored in the storage unit 11.

Additional learning data is learning data acquired from the user after the start of use. The heart rate feature quantity vector x of the additional learning data is created by the concentration level estimation unit 15 and will be described in the concentration level estimation unit 15. The concentration vector w of the additional learning data is created by the conversion unit 13 and will be described in the conversion unit 13. FIG. 4 shows an example of additional learning data x ′ ₁ , x ′ ₂ ,... Stored in the storage unit 11.

  The collecting unit 12 will be described. The collection unit 12 collects an index of the degree of concentration of the user by causing the user to input. As this index, there are a subjective concentration determined by the user and a concentration level of the user with respect to the task (in this embodiment, a reaction time with respect to the task). The collection unit 12 uses the display function and touch panel function of the smartphone. Specifically, the collection unit 12 displays a guidance screen for the user to input on the display of the smartphone, and causes the user to input a screen on the touch panel according to the guidance screen. Then, the collection unit 12 records the input information. This recorded information is used by the conversion unit 13.

  Subjective concentration is collected by VAS [Visual Analog Scale]. VAS is described as 0 [not concentrating] and 100 [concentrating] at both ends of a horizontal line of 100 [mm], and the horizontal line at the position that best fits the subjectivity of the user. This is a technique to draw a line. FIG. 5A shows an example of a display screen on the display for inputting the subjective concentration degree by VAS, and a line input by the user is drawn at a position closer to “concentrated”. ing. The collection unit 12 measures the distance from the left end of the line drawn with respect to the 100 mm horizontal line in mm units, and sets the value as the subjective concentration. When collecting the subjective concentration, the user is made to input the subjective concentration at the time of work such as desk work (for example, creation of a sentence by a personal computer) and a meeting. As shown in FIG. 6 (a), the heart rate feature amount measurement interval corresponding to the input subjective concentration level is an interval (desk work, conference, etc.) before the input timing of the subjective concentration level. Section).

  As the reaction time, for example, the time from when a predetermined portion in the screen of the display shines until the user presses the screen is collected. The reaction time may be collected only once and may be the reaction time of one time, or may be collected a plurality of times during a predetermined time (for example, 5 minutes) and the average reaction time may be obtained. FIG. 5B shows an example of a display screen on the display for collecting the reaction time. When the circular portion at the center of the screen shines, it is pushed by the user with the touch panel function. The collection unit 12 measures the time from when this light is emitted until it is pressed, and sets it as the reaction time. When collecting the reaction time, it may be performed at any time when work such as desk work or conference is not performed. The heart rate feature amount measurement interval corresponding to the collected reaction time is the same as the interval in which the task of inputting the reaction time is performed, as shown in FIG. After the reaction time is collected a plurality of times in this section, the average value of the reaction times of the plurality of times is calculated.

  The conversion unit 13 will be described. The conversion unit 13 converts the subjective concentration level and reaction time collected by the collection unit 12 into a concentration level (resting class belonging probability and concentrated class belonging probability). Before specifically describing the processing in the conversion unit 13, how to determine the belonging probability of each class will be described. FIG. 7 shows an example of the relationship between the subjective concentration and reaction time collected in a prior experiment by five arbitrary persons and the θ wave content rate (concentration). FIG. 7A shows the relationship between the subjective concentration and the θ wave content, and the subjective concentration increases as the θ wave content increases. When this data is linearly regressed, a linear regression line L1 is obtained. FIG. 7B shows the relationship between the reaction time and the θ wave content, and the reaction time is shortened as the θ wave content increases. When this data is linearly regressed, a linear regression line L2 is obtained. As can be seen from the example of FIG. 7, the subjective concentration level and the reaction time are information input by a person, and thus have a correlation with the input concentration level (the content of θ waves of brain waves). Therefore, by extracting this correlation by linear regression, the θ wave content rate (concentration level) can be estimated from the subjective concentration level and the reaction time.

However, as can be seen from the example of FIG. 7, the subjective concentration level and the reaction time are a human subjective input and a human action, and thus there is a variation between the concentration level (the θ wave content rate of the electroencephalogram). . As described above, since there is a variation (error) between the concentration level, the subjective concentration level, and the reaction time, it is necessary to consider the uncertainty due to this variation when using the subjective concentration level and the reaction time for learning. is there. As shown in FIG. 8, it is assumed that the variation between the θ wave content rate (concentration level) and the subjective concentration level follows a Gaussian distribution D in the present embodiment. For this Gaussian distribution, the linear regression equation f (x) of Equation (1) and the variance σ ² of the regression residual are obtained, and these are used as Gaussian distribution parameters (average f (x), variance σ ² ). In the present embodiment, the proportion of the area of the Gaussian distribution D that is larger than the threshold S (shaded portion) is the concentration class belonging probability, and the proportion of the area of the Gaussian distribution D that is smaller than the threshold S (plain portion) is resting. Class membership probability. This area can be obtained from a normal distribution table or a known function. In addition to the linear regression, a non-linear function such as a quadratic polynomial may be used for the correlation.

In order to obtain the linear regression equation f (x) and the variance σ ² expressed by the equation (1), the data of the electroencephalogram (θ wave content rate) and the data of the subjective concentration and the reaction time are required. Basically, brain waves cannot be measured from the user. Therefore, in preliminary experiments, we measure brain waves from a large number of unspecified people, and collect subjective concentration and reaction time. The collection of each data may be performed together with the collection of basic learning data. Then, linear regression is performed using the electroencephalogram (θ wave content) data and each data of the subjective concentration and the reaction time, and the linear regression equation f (x) for the subjective concentration and the variance σ of the regression residual ² , the linear regression equation f (x) for the reaction time and the variance σ ² of the regression residual are obtained. The conversion unit 13 uses the linear regression equation f (x) and the variance σ ² obtained in advance. When the user's brain wave can be measured, the conversion unit 13 may obtain the linear regression equation f (x) and the variance σ ² based on the user's brain wave data. If the user's linear regression equation f (x) and variance σ ² can be obtained, the adaptation to the individual user can be performed with higher accuracy.

In the conversion unit 13, when the subjective concentration is collected by the collection unit 12, a Gaussian distribution corresponding to the subjective concentration is set using the linear regression equation f (x) and the variance σ ² for the subjective concentration, The Gaussian distribution is divided by the threshold value S to calculate the belonging probability of the rest class and the belonging probability of the concentrated class. Further, in the conversion unit 13, when the reaction time is collected by the collection unit 12, a Gaussian distribution corresponding to the reaction time is set using the linear regression equation f (x) and the variance σ ² for the reaction time, The Gaussian distribution is divided by the threshold value S, and the belonging probability of the rest class and the belonging probability of the concentrated class are calculated. Each time the conversion unit 13 converts the belonging probability of the rest class and the belonging probability of the concentration class, four heart rate feature amounts of the corresponding section calculated by the concentration degree estimation unit 15 are associated with each other, and the heart rate feature amount vector A pair of x ′ and the concentration vector w ′ is stored as additional learning data in the storage unit 11. The learning unit 14 learns the heartbeat feature vector x ′ and the concentration vector w ′ as learning data in order to adapt to the individual user.

The learning unit 14 will be described. The learning unit 14 performs learning by secondary discriminant analysis using the basic learning data and the additional learning data stored in the storage unit 11. In this learning, learning is performed separately for a rest class and a concentrated class, and an average vector and a variance-covariance matrix for each class are calculated. Specifically, the learning unit 14 calculates a weighted sample average vector for each class j using Equation (2). Further, the learning unit 14 calculates the weighted sample variance covariance S _j for each class j by using the calculated weighted sample average vector according to Equation (3). Note that j is a class number, {1 (= rest class), 2 (= concentrated class)}. l is the number of basic learning data. u is the number of additional learning data. w _ij is a weight vector (concentration degree vector) and is {w _i1 (= rest class probability), w _i2 (= concentration class probability)}. x _i is a heartbeat feature vector.

  The weighted sample average vector and the weighted sample variance covariance of each class obtained by the learning unit 14 are used when the concentration degree estimation unit 15 estimates the concentration degree from the heartbeat feature amount vector. The learning frequency in the learning unit 14 may be learned every time one additional learning data is added, or may be learned every time a predetermined number of additional learning data is added.

The concentration degree estimation unit 15 will be described. The concentration degree estimation unit 15 calculates four heart rate feature amounts using the electrocardiogram detected by the heart rate sensor 10, and uses the four heart rate feature amounts for two classes of concentration (rest when the θ wave content rate is small). Estimate class and concentration class when large). This estimation is performed by the secondary discriminant analysis (QDA) as described above, and when learning is already performed in the learning unit 14, the learning result (weighted sample average vector and weighted sample variance of each class) Covariance) is used. Specifically, the concentration degree estimation unit 15 acquires RR interval data from time series data of a cardiac potential for a predetermined time detected by the heart rate sensor 10, and RRV, LF / from the RR interval data for the predetermined time HF, centroid frequency, and peak frequency are calculated. Then, the concentration level estimation unit 15 calculates the Mahalanobis distance D _j (x) for each class j by using the heart rate feature vector x consisting of RRV, LF / HF, barycentric frequency, and peak frequency according to equation (4). calculate. Further, the concentration level estimation unit 15 estimates the concentration level (rest class, concentration class) c (x) according to Equation (5) using the Mahalanobis distance D _j (x) of each class. In addition, in the initial stage where there is no additional learning data and the learning unit 14 has not yet performed the learning, the weighted sample average vector and the weighted sample variance covariance of each class are set to preset initial values. Use.

  The display unit 16 will be described. The display part 16 uses the display function by the display of a smart phone. The display unit 16 displays the estimation result (rest class, concentration class) of the concentration level in the concentration level estimation unit 15 on the display. The display unit 16 may display other information related to the estimation result in addition to the concentration degree estimation result.

With reference to FIG. 1, the flow of operation in the concentration degree estimation apparatus 1 will be briefly described. The user's smartphone has an application for estimating the degree of concentration. The storage unit 11 stores basic learning data in advance. The conversion unit 13 is preset with a linear regression line f (x) and variance σ ₂ for the subjective concentration and a linear regression line f (x) and variance σ _{2 for the} reaction time. The heart rate sensor 10 is worn on the chest of the user.

  When the use is started, the heart rate sensor 10 always detects the user's cardiac potential and wirelessly transmits the cardiac potential data to the smartphone. The smartphone receives this electrocardiographic data. The concentration level estimation unit 15 extracts RR interval data from the electrocardiographic data for a predetermined time, and calculates RRV, LF / HF, barycentric frequency, and peak frequency (heart rate feature vector) from the RR interval data for a predetermined time. .

When the subjective concentration can be collected from the user, the collection unit 12 collects the user's subjective concentration by VAS. Alternatively, if the user's reaction time can be collected, the collection unit 12 collects the reaction time by the user's reaction input operation. Each time the collection unit 12 collects the subjective concentration or reaction time, the conversion unit 13 sets a Gaussian distribution corresponding to the subjective concentration or reaction time using the linear regression equation f (x) and the variance σ ^2. Then, the Gaussian distribution is divided by the threshold value S to calculate the belonging probability of the rest class and the belonging probability of the concentrated class. The calculated concentration vector consisting of the calculated affiliation probabilities of each class and the heart rate feature vector of the corresponding section are stored in the storage unit 11 as additional learning data.

  When additional learning data is newly added to the storage unit 11, the learning unit 14 calculates a weighted sample average vector for each class j using Equation (2). Further, the learning unit 14 calculates the weighted sample variance covariance for each class j using Equation (3) using the weighted sample average vector of each class j.

  The concentration estimation unit 15 calculates the Mahalanobis distance for each class j using equation (4) using the weighted sample average vector and the weighted sample variance covariance for each class each time the heart rate feature vector x is calculated. calculate. Furthermore, the concentration level estimation unit 15 estimates the concentration level class using Equation (5) using the Mahalanobis distance of each class. The display unit 16 displays the estimated degree of concentration (rest class, concentration class) on the display.

  According to this concentration estimation apparatus 1, the subjective concentration and reaction time by the user's input are collected, and the heart rate feature amount of the user and the concentration converted from the subjective concentration and reaction time are learned as learning data. As a result, the relationship between the heartbeat feature amount and the degree of concentration (theta wave of the electroencephalogram) can be adapted to the individual user, and the concentration level of the user can be estimated with high accuracy.

  Further, according to the concentration degree estimation apparatus 1, learning is performed in consideration of the subjective concentration degree and the variation in reaction time (and consequently the variation in the concentration degree converted from the subjective concentration degree and the reaction time) due to the input of the subject. Thus, the influence of uncertain additional learning data on learning can be suppressed, and the estimation result of the degree of concentration does not change suddenly by learning, and stable estimation is possible. For example, even when there is a subjective concentration or reaction time with a large error, the influence on the estimation result is small. Further, according to the concentration degree estimation device 1, since additional learning data of the user is gradually added, the tendency of the concentration degree estimation gradually adapts to the individual, so there is no sense of incongruity.

  Further, according to the concentration level estimation device 1, additional learning data can be easily collected because the user only has to input the subjective concentration level or input a simple task using the touch panel function of the smartphone. Since the user only performs such input, the burden is small. In addition, according to the concentration estimation apparatus 1, by configuring the smartphone to be always carried by the user, it is possible to increase the opportunity to collect the user's subjective concentration and reaction time, and collect a lot of additional learning data. can do.

  With reference to FIG. 1, the concentration degree estimation apparatus 2 according to the second embodiment will be described. Compared with the concentration degree estimation device 1 according to the first embodiment, the concentration degree estimation device 2 is different in that learning is performed with an emphasis on additional learning data as the number of additional learning data increases. Therefore, the concentration degree estimation device 2 includes a learning unit 24 instead of the learning unit 14 of the concentration degree estimation device 1 according to the first embodiment. In the second embodiment, the learning unit 24 corresponds to learning means described in the claims. In the second embodiment, only the learning unit 24 will be described.

  In the concentration estimation apparatus 1 according to the first embodiment, learning is performed by handling the basic learning data and the additional learning data in the same manner. However, this learning is learning for adapting to the individual user, but the basic learning data is not data obtained from the user. Therefore, in the concentration level estimation device 2, the learning is performed with emphasis on the additional learning data by reducing the influence on the learning of the basic learning data as the number of the additional learning data increases.

Specific processing in the learning unit 24 will be described. The learning unit 24 performs learning by adding a weight according to an increase in the number of additional learning data to the learning in the learning unit 14 according to the first embodiment. Specifically, the learning unit 24 introduces a weight parameter a _i represented by Expression (6). The weight parameter a _i is fixed to 1 when the learning is performed with the additional learning data, and is decreased as the ratio of the number u of the additional learning data is increased. The learning unit 24 uses the weight parameter a _i to calculate a weighted sample average vector for each class j using Equation (7). Further, the learning unit 24 calculates the weighted sample variance covariance S _j for each class j using Equation (8) using the weighted sample average vector and the weight parameter a _i of each class.

  According to this concentration level estimation device 2, the influence on the learning of the additional learning data becomes larger by performing the learning with an emphasis on the additional learning data as the number of the additional learning data increases (the influence on the learning of the basic learning data). The relationship between the heartbeat feature amount and the degree of concentration (the brain wave θ wave) can be adapted to the individual user, and the degree of concentration of the user can be estimated with higher accuracy.

  With reference to FIG. 1, a concentration estimation apparatus 3 according to a third embodiment will be described. Compared with the concentration level estimation device 1 according to the first embodiment or the concentration level estimation device 2 according to the second embodiment, the concentration level estimation device 3 collects subjective concentration levels and the like based on user input. The difference is that the method has been improved. Therefore, the concentration degree estimation device 3 includes a collection unit 32 instead of the collection unit 12 of the concentration degree estimation devices 1 and 2 according to the first and second embodiments. In the third embodiment, the collection unit 32 corresponds to a second information collection unit described in the claims. In the third embodiment, only the collecting unit 32 will be described.

  In the concentration level estimation apparatuses 1 and 2 according to the first and second embodiments, after a task such as desk work is performed, the user is made to input the subjective concentration during the task. However, depending on the user, the input is forgotten, and additional learning data cannot be obtained sufficiently if the subjective concentration cannot be collected. Therefore, the concentration level estimation device 3 recognizes the user's behavior and prompts the user to input the subjective concentration level according to the result of the behavior recognition. For example, when walking is recognized during desk work, it is considered that the desk work is interrupted or terminated. Therefore, when the user walks in a state where the subjective concentration is not input after the desk work is finished, the user is prompted to input the subjective concentration in the desk work before the start of walking in the stationary state after the end of walking. An acceleration sensor mounted on a smartphone is used to determine whether or not walking. Moreover, the vibrator function and alarm function of a smart phone are utilized for prompting the user to input.

  Specific processing in the collection unit 32 will be described. The collection unit 32 determines whether or not the norm of acceleration detected by the acceleration sensor of the smartphone is equal to or greater than a threshold value, and if it is equal to or greater than the threshold value, estimates that the user is walking or is doing some work. If it is less than the threshold, it is estimated that the user is seated. When it is estimated that the user is seated (stationary state), the collection unit 32 vibrates with a vibrator function or generates an alarm sound with an alarm function when the stationary state continues for a certain period of time. Displays a screen for inputting the subjective degree of concentration by VAS. For example, a sentence such as “Please input the degree of concentration during desk work before walking” is inserted into the screen to be displayed. In addition to the method for determining the norm of acceleration, it may be determined by various other methods such as frequency analysis of the norm of acceleration. Moreover, you may estimate whether it is walking using information other than acceleration.

  In the walking section, fluctuations in the heart rate due to exercise increase. Therefore, the heartbeat feature amount in this section cannot be used as additional learning data. Therefore, the heart rate feature amount measurement section corresponding to the subjective concentration inputted after walking is a section before walking as shown in FIG.

  In addition, when it is estimated that the subject is in a stationary state, input of the subjective concentration may be prompted when there is a sudden fluctuation in the heartbeat. Also, it acquires physiological information such as heartbeats, records the time when the acquired physiological information fluctuated greatly, shows the time when the physiological information fluctuated greatly after returning to the steady state, and the fact that it changed. The input of the subjective concentration at that time may be prompted. Further, the input of the subjective concentration degree may be prompted after an arbitrary event ends. In addition, when it is considered that the work is continued (for example, when the state of high concentration of the user continues), input of the subjective concentration may be waited until it is estimated that the user is resting. Also, instead of inputting the subjective concentration degree only once, the input of the subjective concentration degree may be prompted a plurality of times at a predetermined time interval (for example, every 10 minutes) based on the timing of prompting each input described above. Moreover, although the example of a subjective concentration degree is shown, it can apply similarly about reaction time.

  According to the concentration estimation device 3, by recognizing the user's behavior, physiological state, etc., it is possible to prompt input of subjective concentration, etc. at an appropriate timing, and to collect more additional learning data Can do. As a result, the user can be adapted more individually, and the user's concentration can be estimated with higher accuracy.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is implemented in various forms, without being limited to the said embodiment.

  For example, in the present embodiment, the concentration estimation device is configured using a smartphone, but the concentration estimation device may be configured in a mobile terminal other than a smartphone, or a portable type such as a tablet computer or a laptop computer. The concentration estimation device may be configured on a personal computer, the concentration estimation device may be configured on a car navigation system mounted on a vehicle, or the concentration estimation device may be configured on a desktop personal computer. Alternatively, the detected heart rate data and the collected subjective concentration level may be transmitted to a center server, a cloud computer, or the like, and the concentration level estimation device may be configured in these remote computers. When the concentration estimation device is configured in the car navigation system, it is possible to determine whether the vehicle is stopped from the vehicle information, and to prompt the user to input the subjective concentration on the navigation screen when the stop time continues for a certain time. By comprising in this way, additional learning data can be collected after a driving | operation completion even in the situation where a smart phone etc. cannot be operated during a vehicle driving | operation, and a collection rate can be improved.

  In the present embodiment, the heartbeat is applied as the first information correlated with the degree of concentration. However, the first information may be other information as long as there is a correlation with the degree of concentration. Other physiological information such as body movement information such as body shake and eye movement may be used, and in the case of a vehicle driver, driving such as inter-vehicle distance, steering fluctuation, yaw rate change, etc. It may be information.

  In this embodiment, the subjective concentration and reaction time using the touch panel of the smartphone are applied as the second information correlated with the concentration input by the user. However, as the second information, the concentration and Other correlated information may be used, for example, the answer time and correct answer rate of a calculation task, and the reaction time and score of an action game. Also, the input method may be other input such as voice.

  In the present embodiment, the concentration level is estimated with two classes of concentration and rest, but the concentration level may be estimated with three or more classes.

  DESCRIPTION OF SYMBOLS 1, 2, 3 ... Concentration degree estimation apparatus, 10 ... Heart rate sensor, 11 ... Memory | storage part, 12, 32 ... Collection part, 13 ... Conversion part, 14, 24 ... Learning part, 15 ... Concentration degree estimation part, 16 ... Display Department.

Claims (2)

A concentration estimation device for estimating the concentration of a target person,
First information detecting means for detecting first information correlated with the degree of concentration from the target person;
A concentration degree estimating means for estimating the concentration degree from the first information detected by the first information detecting means;
Second information collecting means for collecting second information correlated with the degree of concentration by the input of the target person;
Conversion means for converting the second information collected by the second information collection means into a degree of concentration;
Learning means for learning, as learning data, the first information detected by the first information detecting means corresponding to the second information collected by the second information collecting means, and the degree of concentration converted by the converting means;
With
The concentration degree estimation device, wherein the concentration degree estimation means estimates the concentration degree from the first information using a learning result in the learning means. The conversion means calculates a variation in the degree of concentration converted from the second information,
The concentration learning apparatus according to claim 1, wherein the learning unit learns in consideration of variation in the concentration calculated by the conversion unit.

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