JPH07156682A - Awakening condition detecting device - Google Patents

Abstract

PURPOSE:To attain surely and quickly detecting decrease in an awakening condition by integrating a continued time relating to an eye closed time of a wink detected by a wink detecting means, and judging an awakening degree decreased condition when this integrated value is increased to a preset value or more within a prescribed time. CONSTITUTION:A wink detecting means 1 for detecting a wink of a subject, that is, opening/closing condition of an eye is provided, to feed a signal to an arithmetic means 2 when closing the eye is detected. The arithmetic means 2, having a timer, receives the signal from the wink detecting means 1 to calculate an eye closed time stored. By integrating the eye closed time, when this integrated value is increased to a prescribed set value or more within a prescribed time, an awakening condition is decided to decrease, and when decreasing the awakening condition is decided, a driver or the like is informed of decreasing the awakening condition by a notice awakening means 3 and forced to awaken. As the wink detecting means 1, a CCD camera or the like for photographing a face image data of the detected person is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting an awake state of a vehicle driver or the like by utilizing blinking (opening and closing of eyelids).

[0002]

2. Description of the Related Art As a conventional example of a device for detecting an awakening state using blinking, for example, Japanese Patent Laid-Open No. 63-25822.
There is a "drowsiness detector" disclosed in Japanese Patent Laid-Open No. In this device, a blink with a closed time of a predetermined time or more is detected, and when the number of times of blinking reaches a predetermined number of times within a predetermined time, a dozing state, that is, the awakening level drops below a reference value. It is determined that the state is present and an alarm is issued. For example, if five blinks with a width of 0.3 seconds or more appear within one minute, the alarm is activated.

[0003]

However, in the above-described conventional statistical processing method for determining the wakefulness by blinking, only the case where the change process in the human biological phenomenon is the same pattern is considered. However, no consideration was given to the fact that there are various patterns in the process of lowering wakefulness. Therefore, there is a problem that, for example, even if the arousal level suddenly decreases and long closed eyes appear, an alarm is not issued unless the number of closed eyes reaches a predetermined number. For example, as an example of a case where the arousal level is rapidly reduced, there is a blinking appearance pattern as described later with reference to FIG. In such a case, when the conventional method is applied, in the electro-oculography data shown in FIG. 3, up to five blinks (numbers 1 to 5) of 0.3 seconds or more are detected, and an alarm is finally issued.
However, in this case, since a considerably long closed eye (T3) has appeared before the fifth blink, the arousal level is already extremely low at that time, and at that time Although it is necessary to issue an alarm, the conventional method has a problem that the time of alarm generation may be significantly delayed from the time when it is necessary.

The present invention has been made to solve the problems of the prior art as described above, and various arousals such as a pattern in which the arousal level gradually decreases and a pattern in which the arousal level rapidly decreases. It is an object of the present invention to provide a wakefulness detecting device capable of surely and promptly detecting a decrease in wakefulness in any of the degree-decreasing patterns. Also,
Another object of the present invention is to provide a wakefulness detection device capable of detecting the degree of decrease in wakefulness, that is, the degree of wakefulness.

[0005]

In order to achieve the above object, the present invention is constructed as described in the claims. That is, in the invention according to claim 1, for the blink detection means for detecting the open / closed state of the eyelids, and for the eye closing time of the blink detected by the eye blink detecting means, the duration is sequentially integrated, and the value is closed. It is configured to include a time integrated value, and a calculating unit that determines that the awakening degree is in a lowered state when the eye closing time integrated value becomes equal to or more than a predetermined set value within a predetermined time. It should be noted that this configuration corresponds to, for example, a configuration in which the duration of closing the eyes is sequentially added up for all the blinks in the first embodiment described later. Further, in the invention according to claim 2, the blink detection means for detecting the open / closed state of the eyelids, and the eye closing time of the blink detected by the blink detecting means, the duration of which is the reference eye closing time or more in order. And integrating the value as the eye-closing time integrated value, and when the eye-closing time integrated value becomes a predetermined set value or more within a predetermined time, it is determined that the awakening degree lowering state. is doing. Note that this configuration corresponds to, for example, a first embodiment described below. Further, a specific example of the blink detection means is also described in the first embodiment described below.

The invention described in claim 3 is the same as claim 2
In the wakefulness detection device according to, the means for counting the cumulative number of blinking eyes used for the integration when the eye closing time integrated value becomes a predetermined set value or more within a predetermined time, and the blinking eyes closed. Means for determining the arousal level based on the number of times of integration. In addition,
This configuration corresponds to, for example, the second embodiment described below. Further, in the invention according to claim 4, in the awakening state detection device according to claim 2, the elapsed time from the start of integrating the blinking eye-closing time until the integrated value of the eye-closing time reaches a predetermined set value is counted. Means, and means for determining the degree of awakening based on the elapsed time. Note that this configuration corresponds to, for example, a third embodiment described below. The invention according to claim 5 is the wakefulness detecting device according to claim 2, wherein the predetermined set value has a plurality of different set values, and the plurality of set values and the eye-closure time integrated value. It is provided with a means for judging the arousal level by comparison with. Note that this configuration corresponds to, for example, a fourth embodiment described below. The invention according to claim 6 is the wakefulness detecting device according to claim 2, wherein the reference eye closing time includes a plurality of reference eye closing times having different values, and the plurality of reference eye closing times and blink eye closing times. It is provided with a means for judging the arousal level by comparison with. Note that this configuration corresponds to, for example, a fifth embodiment described below.

According to a seventh aspect of the invention, in the wakefulness detecting device according to the second to sixth aspects, when a decrease in the wakefulness is detected, the subject is lowered in the wakefulness. It is equipped with means for notifying and awakening the subject. It should be noted that this configuration corresponds to, for example, the configuration described in a first embodiment described later. Specific examples of the notification / wake-up means are described in Tables 1 and 2 below. The invention according to claim 8 is, in the awakening state detection device according to any one of claims 2 to 7, a manual switch that is operated when the subject is aware of a decrease in arousal level, and the manual switch signal. Means for correcting the value of the set value based on the eye-closing time integrated value integrated within a predetermined time before is input. Further, the invention according to claim 9 is the wakefulness detecting device according to claim 8, further comprising means for correcting the reference eye closing time based on the blink eye closing time that appears before the input of the manual switch signal. Is. Further, the invention according to claim 10 is
The alertness detection device according to claim 8 or 9, wherein when a decrease in the alertness is detected, the subject is notified of the decrease in the alertness and the subject is awakened.
Awakening means, and means for operating the notification / wakeup means at a high level when the manual switch signal is input. The claim 8
The configuration described in claim 10 corresponds to, for example, the configuration described in a sixth embodiment described below.

[0008]

In the present invention, in consideration of individual differences in the process of awakening and falling asleep, whether the wakefulness gradually decreases or the wakefulness rapidly decreases, In order to always detect the awakening state appropriately, basically, the judgment is made on the basis of the integrated value of the eye blink closing time within a predetermined time. Also,
The awakening degree is determined from the process of integrating the blinks, based on the characteristics of the blinking, in which the awakening degree decreases as the eye-closing time increases. First, in claim 1, for all the blinks, the duration of closing the eyes is sequentially integrated, and the value is set as the eye closing time integrated value, and the eye closing time integrated value becomes equal to or more than a predetermined set value within a predetermined time. At times, it is determined that the awakening level is low. That is, since the state in which the number of blinks greatly increases indicates a decrease in arousal level, it is determined that the integrated value of the eye-closing time of blinking is equal to or more than a predetermined set value within a predetermined time indicates a low awakening level. You can Further, claim 2 sequentially integrates the eye closing time duration of the reference eye closing time or longer, and sets the value as the eye closing time integrated value, and the eye closing time integrated value is a predetermined set value within a predetermined time. When it becomes the above, it is judged that the state of awakening is lowered. In other words, blinks with a very short duration occur even when the wakefulness is normal, so select a duration that is greater than or equal to the predetermined value (reference eye closing time), and set the value obtained by integrating these values within the predetermined time. When the value is equal to or more than the value, it is determined that the state is lower in arousal level. With this configuration, it is possible to exclude the eye closing time due to normal physiological blinking from the integrated value.

Further, claim 3 shows that even if the integrated value of eye-closing time is the same, the one having a longer eye-closing time per one time (the one having a smaller number of eye-closing times) has lower awake state. Based on this, when the integrated value of the eye-closing time is equal to or more than a predetermined set value within a predetermined time, the number of times of blinking eyes used for the integration is counted, and the awakening degree is determined based on the number of times of integration. . That is, the smaller the number of integrations when the integrated value of the eye-closure time becomes equal to or greater than the set value, the lower the awakening state becomes, and therefore the awakening degree can be determined from this value. In addition, claim 4 is,
If the eye closing time per one time is long or the eye closing occurs frequently, it is indicated that the awake state is lowered, and the eye closing time integrated value is set to a predetermined set value after the eye blink closing time is started to be integrated. The elapsed time until is calculated, and the awakening degree is determined based on the elapsed time. That is, the shorter the elapsed time until the integrated value of the eye-closure time becomes the predetermined set value, the lower the awakening state becomes. Therefore, the awakening degree can be determined from this value. Also,
According to a fifth aspect of the present invention, a plurality of set values having different values are provided as a set value serving as a comparison reference of the eye closed time integrated value based on the fact that the larger the eye closed time integrated value within a predetermined time is, the lower the arousal level is. The awakening level is determined by comparing the value with the integrated value of the eye-closing time. That is, the greater the set value that the eye-closing time integrated value exceeds, the lower the awakening degree. Therefore, the awakening degree can be determined depending on which set value the eye-closing time integrated value exceeds. Further, claim 6 has a plurality of reference eye closing times having different values as the reference eye closing time for determining whether or not to integrate based on the fact that the longer the eye blink closing time is, the lower the arousal level is, The awakening degree is determined by comparing a plurality of reference eye closing times with blinking eye closing times. That is,
The length of the blinking eye-closing time is detected by the reference eye-closing time.

A seventh aspect of the present invention is a combination of the wakefulness detecting device according to any one of the second to sixth aspects and a notification / wakeup means, and when a decrease in the wakefulness is detected, the subject (for example, The driver is notified that the wakefulness has deteriorated and the subject is awakened. Further, the eighth aspect has a function of correcting the set value according to the individual difference of the subject.
That is, the set value that is the criterion for determining the state of decreased arousal is
Strictly speaking, it varies depending on each subject, so it is equipped with a manual switch that is operated when the subject becomes aware of a decrease in arousal level.
By correcting the value of the set value based on the eye-closed time integrated value integrated within the predetermined time before the manual switch signal is input, the set value suitable for the subject can be given. The ninth aspect is provided with a function of correcting the reference eye closure time according to the individual difference of the subject.
That is, the reference eye closing time to determine whether to integrate is also strictly different for each subject, by correcting the reference eye closing time based on the blink eye closing time that appeared before the input of the manual switch signal, It is possible to give the subject a standard eye-closing time suitable for the subject. In addition, claim 10
Is configured to change the operation level (stimulus intensity) of the notification / wake-up means in accordance with the signal from the manual switch. That is, when the signal from the manual switch is input, it indicates that the awakening degree is considerably lowered. Therefore, it is better to operate the notification / wakeup means and perform strong awakening. Therefore, a high level of notification / wakefulness (strong stimulation)
It is configured to operate with. Regarding the relationship between the drowsiness consciousness of the subject and the awakening degree in claims 8 to 10, a sixth example described later and FIG.
Will be described in detail.

[0011]

1 is a block diagram of an embodiment showing the structure of the present invention. In FIG. 1, 1 is a blink detection means,
Reference numeral 2 is a calculation means, and 3 is a notification / wakeup means. First, in the blink detection means 1 (details will be described later), the subject's blink,
That is, the open / closed state of the eyes is detected. Next, a signal is sent to the calculation means 2 when the eye flapping detection means 1 detects the eye closure as described above. The calculation means 2 has a timer and receives a signal from the blink detection means 1 to calculate the eye-closing time. Further, the calculation means 2 has a memory function and stores the eye-closing time. Further, a decrease in the arousal state and its degree (awakening degree) are determined from the value obtained by integrating the individual eye-closing time (details will be described later). The result determined by the calculation means 2 may be used as, for example, data for research and development, or may be used as a signal for driving a practical means such as the notification / wakeup means 3. As described above, the basic configuration of the present invention comprises the blink detection means 1 and the calculation means 2, but as shown in FIG. 1, the notification / wakeup means 3 is provided and the awakening detected by the calculation means 2 is provided. When the decrease in the awakening level becomes equal to or lower than a predetermined reference value, the notification / wakeup means 3 may be configured to notify the driver or the like of the decrease in the awakening level or forcibly awaken.

As the blink detecting means 1, for example, the following means (1) to (3) can be considered. (1) Means Using Electrodes Using a pair of electrodes, one is attached to the upper part of the eyebrows of the subject (for example, the driver) and the other is attached to the lower part of the lower eyelid. Then, the action potential (ocular potential) of the muscle that causes blinking is transmitted to the receiver side by a transmitter and an antenna attached to the body surface, and the output of the receiver is taken out by a differential amplifier. This output is as shown in the electro-oculogram waveform diagram of FIG. 2 described later, and becomes high level when the eyes are closed. Therefore, by determining whether the voltage is higher or lower than the predetermined reference voltage, it is possible to detect the eye-closed state in which the eyelids are closed. (2) Means consisting of light emitting element and light receiving element Light (eg, infrared light so as not to cause glare) is projected from the light emitting diode mounted on the eyeglass frame or the like to the position of the eye of the subject, and the eyeball or The phototransistor receives the reflected light reflected by the eyelids. In this case, the distance from the light-emitting element and the light-receiving element is shorter in the eyelid than in the eyeball, and the light reflected by the skin-colored eyelid is stronger than the light reflected by the black cornea of the eyeball, so that the eye is closed Moreover, the output voltage of the phototransistor becomes large. Therefore, the output of the phototransistor is compared with a reference value, and when the output is equal to or higher than the reference value, it can be determined that the eyelid is closed and the eye is closed. (3) Means of using image processing C fixed to an instrument panel or the like in front of the subject
The face image data of the subject is photographed by the CD camera, the photographed face image data is converted into a digital image frame by frame, and the digital image is sent to the frame memory of the image processing apparatus. In the image processing apparatus, the binarization processing is performed so that hair, eyebrows, eyes, etc. become black pixels and other portions become white pixels. Then, the left and right contour lines of the face, that is, the face width is recognized based on the continuity of the white pixels. Next, the center line of the face is obtained from the face width, and the eyes (black pixels) are detected in the area surrounded by the center line and the left and right face widths. Then, the degree of opening of the eye is obtained from the size of the area of the black pixel corresponding to the eye, the aspect ratio, and the like, and the open / closed eye can be determined from this value. Note that, among the means (1) to (3), (1) and (2) are used at the research and development stage because it is necessary to attach electrodes, glasses, etc. to a subject such as a driver. Suitable for equipment. Further, the means (3) allows non-contact detection, which is suitable as a practical device. Also,
As the notification / wake-up means 3, sound (means for generating a buzzer sound, etc.), scent (means for giving stimulating menthol, etc.), air conditioning (on / off of air conditioner, temperature, air volume, etc. are controlled) Means), vibration (means for vibrating a seat or the like), etc., means for making an announcement or awakening, or a combination thereof (details will be described later).

(Operation) The operation of the first embodiment will be described below. First, the relationship between blinking and arousal level will be described with reference to FIG. FIG. 2 is an eye movement (EOG) representing the relationship between the electro-oculography data and the arousal level (alertness index) obtained by measuring the electro-oculography above and below the eye.
It is a figure which shows a rating standard. In FIG. 2, the part where the waveform rises (high level part) shows the eye closed state, and the low level part shows the eye opened state. First, in a clear state where the degree of arousal is high (the degree index 3), a fast and sharp waveform appears. That is, fast and sharp blinks occur at intervals.

Next, in a state in which the degree of awakening is slightly lowered (the degree of awareness index 2.5), the number of blinks increases. As the arousal level gradually decreases (awareness index 2), the eye blinks slowly (a waveform with a slightly longer duration than the awakening index 3)
Appears. When the arousal level further decreases, short eye closure (awareness index 1.5) and long eye closure (awareness index 1) appear.
The appearance of such a waveform indicates that it is in a dull state before falling asleep. Note that the closed eye in FIG. 2 is a state in which the closed eye state continues for a considerably longer period than the normal blinking. As described above, the change in the blinking state is used as an index of the arousal level, and the longer the eyes are closed, the lower the arousal level is. In addition, there are individual differences in the process of decreasing the arousal level in a vehicle driver or the like, and in some cases, as shown in the order of FIG. In some cases, the arousal level may suddenly decrease and the state may suddenly change from 3 to 1. FIG. 3 is a signal waveform diagram showing an example of actual electro-oculography data and a waveform obtained by signal processing the data. In FIG. 3, is the electro-oculography data, is the eye-closure signal obtained by signal processing the electro-oculography data (when the high level is closed:
Eye-closing time Tn), an integrated value T of eye-closing time, and a predetermined set value Td. In the present embodiment, when the blink signal as shown in FIG. 3 appears as the detection signal of the blink detection means 1, the computing means 1 first compares the blink eye closing time with the reference eye closing time Ta and blinks longer than Ta. The eye-closing time T1, T2, T3, ... Is detected. Then, the eye-closing time is integrated, and when the eye-closing time integrated value T, which is the total value, becomes equal to or more than the set value Td within the predetermined time Tc, it is determined that the awakening degree is significantly decreased (drowsy state). It is configured to do.

The details will be described below with reference to the flow chart shown in FIG. In FIG. 4, first, when the ignition switch is turned on, the wakefulness detecting device is started (steps 100 and 101). Next, n is set to 1 (step 102), and when the first eye closing is detected (steps 103 and 104), the timer is started (step 105) and the first blinking eye closing time T1.
Is calculated (step 106). If "no" in the above step 103, that is, if the eyes are not closed, the process returns to step 103 and the eye condition is detected until the eyes are closed. Next, in step 107, the eye blink closing time T1
Is equal to or longer than the reference eye-closing time Ta, and if T1 <Ta (step 107 = "no"), the elapsed time T
b is calculated (step 108), and if the value does not reach the predetermined time Tc (step 109), n = 1 remains,
It returns to step 103 which detects the state of an eye again. In step 107, the eye blink closing time T1 is the reference eye closing time Ta.
If it is above (step 107 = "yes"), the value is integrated (step 110). In this case, since the eye is closed for the first time, the eye-closure time integrated value T = T1. Next, at step 111, the eye-closing time integrated value T is set to the set value T.
Determine if it is greater than or equal to d. When T <Td (step 11)
1 = “no”), set n = n + 1. That is, in this case, n = 2 (step 112), and if the elapsed time Tb is within the predetermined time Tc (step 10).
8, 109), and again from step 103 to step 107
repeat. By repeating the above route, the eyes closed for the reference eye closing time Ta or more are sequentially integrated from T1 to Tn (T = T1 + T
2 + ... + Tn) On the other hand, if “yes” (T ≧ Td) in step 111, it is determined in step 115 that the awakening level has significantly decreased (drowsy state). If step 115 is passed or if "no" is determined in step 109 (that is, elapsed time Tb ≧ predetermined time Tc), the process returns to step 102 and the calculation is repeated from n = 1 again. For example, when the electro-oculography data as shown in FIG.
When three blinks 2 and 3 are input, the eye-closure time integrated value T (= T1 + T2 + T3) becomes the set value Td or more. The elapsed time Tb at this time is less than or equal to the predetermined time Tc. Therefore, when the eye-closing time integrated value T reaches the set value Td, it is determined that the subject is in a dozing state, and at this time, an alarm (starting the notification / wake-up means 3) can be issued. In the case of the conventional example, even in such a case, the alarm is delayed until the time when five blinks are input (T5 in FIG. 3). Therefore, in the present embodiment, it is possible to detect the deterioration of the wakefulness at an early stage.

Next, the notification / awakening means 3 will be described. Generally, a person becomes less sensitive to a stimulus as the degree of arousal decreases, and for example, when a person falls asleep, it may not be possible to sufficiently awaken with a light stimulus.
Moreover, when the arousal level is slightly lowered, an unnecessarily strong stimulus may be annoying. Therefore, the degree of stimulation by the notification / wake-up means 3 is changed according to the awakening degree of the subject (for example, the driver), and in the case of a drowsiness state in which the awakening degree is significantly reduced, a strong stimulation is given to eliminate the drowsiness state. On the contrary, when the arousal level is slightly lowered, it is necessary to give a light stimulus. Also, changing the intensity of the stimulus according to the arousal level causes the subject to recognize the arousal level, and thus encourages drivers who were not aware of drowsiness to concentrate on driving. It also has the effect of inducing the driver to take a break if he or she still feels fine. As the notification / wakeup means 3, it is effective to use stimuli such as sound, scent, air conditioning, and vibration as described above, alone or in combination. Further, when changing the degree of stimulation, a method of changing the strength with a single kind of stimulation and a method of changing the strength with a combination of a plurality of kinds of stimulation can be considered. When changing the intensity of a single type of stimulus, it can be performed, for example, by changing the parameters as shown in Table 1 below.

[0017]

[Table 1]

Further, as will be described in detail later, when changing the degree of notification / awakening according to the decrease in arousal level, for example, as shown in Table 2 below, pattern A (very strong stimulus), pattern B (somewhat strong) It may be divided into three patterns of strong stimulus) and C pattern (slightly suppressed stimulus), and a suitable pattern may be selected and operated according to the decrease in arousal level.

[0019]

[Table 2]

The means shown in Tables 1 and 2 may be used alone or in any combination thereof. The part described as plural in the column of notification / wake-up means in Table 2 shows one example of the above combination.

As described above, in order to change the strength of the stimulus of the notification / wakefulness means 3 according to the wakefulness, it is not only necessary to detect that the wakefulness has dropped below the reference value, but also the wakefulness It is necessary to judge the degree, that is, the degree of arousal. Hereinafter, examples having a function of determining the arousal level will be described. In the second embodiment of the present invention, it is possible to judge the awakening degree and perform the notification and the awakening according to the judgment. FIG. 5 is a waveform diagram of a blink signal for explaining the second embodiment. In addition, in FIG. 5, the display of the electro-oculography data is omitted. In this embodiment, the appearance pattern of each blink signal is stored, and the awakening level is determined based on the stored pattern. In particular,
The arousal level is determined from both the number of blinks and the eye-closing time integrated value T. For example, as a result of integrating many short blinks as shown in (1) of FIG.
Is greater than the set value Td, the acuity index 2 in FIG.
Corresponding to the case of up to 2.5, it is determined to be the initial state of a decreased alertness. This state is called awakening degree C. In this case, as described in the notification / wakeup means 3 (see Table 2), for example, the operation of the notification / wakeup means is at a slightly suppressed level. Next, as shown in (2) of FIG. 5, when a number of slightly longer blinks are integrated and become equal to or greater than the set value Td, this corresponds to the case of the awareness index 1.5 of FIG. It is judged that the condition has dropped considerably. This state is called awakening degree B. In this case, the notification / awakening means is presented with a slightly stronger strength. Next, as shown in (3) of FIG. 5, when a fairly long blink occurs and the integrated value of 1 or 2 exceeds the set value Td, it corresponds to the case of the awareness index 1 of FIG. However, it is determined that the awakening degree is extremely low, that is, a so-called dozing state. This state is called awakening degree A. In this case, the notification / wake-up means presents a very strong stimulus with a high degree of urgency.

The operation of the second embodiment will be described below with reference to the flow chart shown in FIG. 6, steps 100 to 112 are the same as those in FIG. Next, if the integrated value T is equal to or greater than the set value Td in step 111 (step 111 = "yes"), the awakening degree is determined in step 113 and thereafter according to the number of times of blinks. First, in step 113, the number of integrations n is 1 ≦ n
In the case of <3, the set value is reached a small number of times, which corresponds to the awakening degree A described above. Also, step 113
In the case of "no", it is determined in step 114 whether or not 3≤n <5, and in the case of "yes", it corresponds to the awakening degree B. Further, if “no” in step 114, that is, if the number of times of integration is 5 or more, it corresponds to the awakening degree C. By switching the pattern of the notification / awakening means 3 according to the above-mentioned arousal levels A, B, and C, it is possible to perform notification / awakening according to the arousal level.
As described above, as the notification / awakening means 3, means such as sound, scent, air conditioner, and vibration are used, and the strength of the presentation and the presentation time are changed according to the awakening level, and the awakening degree is greatly reduced. The more stimulating it is, the more stimulating it is. Also, when the vehicle is driving, and the awakening level is considerably low, the emergency flashing light is turned on to decelerate safely, and if it is on a highway, etc., it will switch to the autopilot function. Means can also be realized.

Next, the accuracy of the awakening degree determination in the second embodiment will be described. FIG. 11 is a comparison characteristic diagram of the data determined by the method of the second embodiment and the data determined by the experiment using the biological signal. As the above-mentioned biological signal, three types of data, that is, an electroencephalogram, an electro-oculogram (blink), and a facial expression, are used comprehensively. In FIG. 11, the solid line indicates the value of the arousal level according to the second embodiment, and the broken line indicates the experimental value based on the biological signal. As can be seen from FIG. 11, the determination value according to the second embodiment is very close to the experimental value based on the biological signal, and if configured as in the second embodiment, three types can be obtained by detecting only blinking. It was found that the same determination result as that obtained using the biomedical signal can be obtained.

Next, FIG. 7 is a waveform diagram of a blink signal for explaining the third embodiment of the present invention. It is indicated that the shorter the elapsed time (total integration time) Tb from the start of integration of the eyelid closing time to the set value Td of the eye closure time integration value Tb, the lower the arousal level. Therefore, in this embodiment, the awakening degree is determined based on the elapsed time Tb. As shown in FIG.
The shorter the elapsed time required for integration, the higher the arousal level.

Next, FIG. 8 is a characteristic diagram of the set value Td for explaining the fourth embodiment of the present invention. This embodiment uses the fact that the awakening degree decreases as the integrated value T of the eye closure time increases, and a plurality of set values Td1 to Td3 are used.
Is provided and the arousal level is determined by comparing the set value with the eye-closure time integrated value T. That is, the greater the set value that the eye-closing time integrated value exceeds, the lower the awakening degree. Therefore, the awakening degree can be determined depending on which set value the eye-closing time integrated value exceeds.

Next, FIG. 9 is a characteristic diagram of the reference eye closing time Ta for explaining the fifth embodiment of the present invention. This embodiment utilizes the fact that the awakening degree decreases as the eye blink closing time increases, and a plurality of reference eye closing times T
a1 to Ta3 are provided, and the awakening degree is determined by comparing the reference eye closing time Ta with the blinking eye closing time. That is, the length of the blinking eye-closing time is detected by the reference eye-closing time.

Next, a sixth embodiment of the present invention will be described. In this embodiment, the determination level of the awakening state detection device is corrected according to the operation of a subject (for example, a driver). That is, the present embodiment is provided with a manual switch that is input when the subject becomes drowsy. The input of this manual switch signal means that the arousal level of the subject has decreased considerably. FIG. 12 is a characteristic diagram showing the relationship between the time when the subject operates the switch (the time when he becomes drowsy) and the awakening degree. In FIG. 12, the bar graph value represents the number of times the subject operated the switch for each alertness index, and the broken line graph represents the cumulative ratio of the number of times the switch was operated. As can be seen from FIG. 12, only about 20% of the users operated the switch with a wakefulness index of considerably higher than 6 and the switch was operated when the wakefulness index of 5 or less significantly deteriorated. It was often operated. From this, it is understood that the awakening degree is considerably lowered when the subject becomes aware of drowsiness. Therefore, when the manual switch signal is input before the wakefulness detection device itself detects the decrease in the wakefulness, the maximum value of the eye-closure time integrated value T accumulated within the predetermined time Tc before the manual switch signal is input. By correcting the value of the set value Td to the corrected value Td 'on the basis of (equal to the correction value Td' in FIG. 10), the value of the set value Td serving as the determination reference is changed to a value suitable for the subject. You can do it. Figure 10
FIG. 9 is a characteristic diagram showing a relationship between the set value Td and the correction value Td ′. Further, the reference eye closing time Ta may be corrected based on the blinking eye closing time that appears before the input of the manual switch signal. Furthermore, the notification / wake-up means 3 may be configured to operate at a high level when a manual switch signal is input. That is, when the signal of the manual switch is input, as described with reference to FIG. 12, it indicates that the awakening degree is considerably lowered. Therefore, the notification / wakeup means 3 is operated and strong awakening is performed. Better. Therefore, the notification / wakeup means is configured to operate at a high level (strong stimulus).

[0028]

As described above, according to the present invention, basically, the awakening degree is gradually determined by the fact that the awakening degree is judged based on the integrated value of the eye blink closing time within the predetermined time. Even when the wakefulness decreases, the wakefulness can be detected reliably even when the wakefulness suddenly decreases and the person falls asleep. You can do it. Further, by taking into consideration the characteristic of blinking that the degree of awakening is significantly reduced as the eye closing time is longer, the lower the awakening degree is, the earlier the lowered state can be detected. Further, in the process of integrating the blinks, the arousal level can be determined based on the number of eye closures required for the integration. Therefore, it is possible to switch the notification / awakening stimulus level in stages according to the awakening degree. In addition, by combining with a manual switch that is operated when the subject becomes aware of drowsiness, it is possible to grasp the blink pattern at the time when the driver etc. becomes aware of drowsiness, and the detection accuracy can be further adjusted to individual differences. It can be exactly what you did. In addition,
As an awakening means, various effects can be obtained such that various kinds of stimuli are presented in a stepwise manner according to the awakening degree, or braking is applied to the vehicle so that the vehicle can be awakened more reliably.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a consciousness index and an electro-oculogram waveform.

FIG. 3 is a signal waveform diagram showing electro-oculogram data and processed waveforms in the first embodiment.

FIG. 4 is a flowchart showing an arithmetic processing process of the first embodiment.

FIG. 5 is a signal waveform diagram in the second embodiment.

FIG. 6 is a flowchart showing a calculation process of the second embodiment.

FIG. 7 is a signal waveform diagram in the third embodiment.

FIG. 8 is a characteristic diagram showing the length of a set value in the fourth embodiment.

FIG. 9 is a characteristic diagram showing the length of the reference eye opening time in the fifth embodiment.

FIG. 10 is a characteristic diagram showing a relationship between a set value and an eye-closure time integrated value in the sixth embodiment.

FIG. 11 is a comparison characteristic diagram of a determination result according to the second embodiment and an experimental value based on a biological signal.

FIG. 12 is a characteristic diagram showing the relationship between the time when the subject operates the manual switch (the time when he becomes drowsy) and the awakening degree.

[Explanation of symbols]

 1 ... Blink detection means 2 ... Calculation means 3 ... Notification / wakeup means

Claims (10)

[Claims] 1. A blink detection means for detecting an open / closed state of an eyelid, and the eye closing time of the blink detected by the blink detecting means, the durations thereof are sequentially integrated, and the value is taken as an eye closing time integrated value, and the eye closing is performed. A wakefulness detecting device comprising: a calculating unit that determines that the wakefulness is in a lowered state when the time integrated value becomes equal to or more than a predetermined set value within a predetermined time. 2. Blink detection means for detecting the open / closed state of the eyelids, and eye blink closing times detected by the blink detection means, the durations of which are equal to or longer than the reference eye closing time are sequentially added up, and the values are calculated. An awakening state detection device comprising: an eye-closed time integrated value, and a calculating unit that determines that the eye-closed time integrated value is equal to or higher than a predetermined set value within a predetermined time . 3. The wakefulness detecting device according to claim 2, wherein when the integrated value of the eye closing time becomes equal to or more than a predetermined set value within a predetermined time, the integrated number of blinking eyes used for the integration is counted. And a means for determining the awakening degree based on the cumulative number of times of blinking eyes closed. 4. The wakefulness detecting device according to claim 2, wherein the elapsed time from the start of integrating the blinking eye-closing time until the integrated value of the eye-closing time reaches a predetermined set value, and the elapsed time. A wakefulness detecting device comprising: means for determining a wakefulness based on 5. The awakening state detection device according to claim 2, wherein the predetermined set value has a plurality of set values having different values, and the awakening degree is obtained by comparing the plurality of set values with an eye closing time integrated value. A wakefulness detecting device comprising means for determining. 6. The wakefulness detecting device according to claim 2, wherein the reference eye closing time has a plurality of reference eye closing times having different values, and the awakening degree is obtained by comparing the plurality of reference eye closing times with blink eye closing times. A wakefulness detecting device comprising means for determining. 7. The wakefulness detection device according to claim 2, wherein when a decrease in the wakefulness is detected, the subject is notified of the decrease in the wakefulness, and the test is performed. An awakening state detection device comprising a notification / wakeup means for awakening a person. 8. A wakefulness detecting apparatus according to any one of claims 2 to 7, wherein a manual switch to be operated when a subject is aware of a decrease in wakefulness, and the manual switch signal are input. And a means for correcting the value of the set value on the basis of the integrated value of the eye-closure time accumulated within a predetermined time before the wakefulness detecting device. 9. The awake state detecting apparatus according to claim 8, further comprising means for correcting the reference eye closing time based on the blink eye closing time that appears before the input of the manual switch signal. Detection device. 10. The wakefulness detecting device according to claim 8 or 9, wherein when a decrease in wakefulness is detected, the subject is informed of the decrease in wakefulness and the subject is awakened. A wakefulness detecting apparatus comprising: a notification / wakeup means for causing the notification / wakeup means to be operated at a high level when the manual switch signal is input.