JPH0638793B2 - Arousal level detector - Google Patents

Description

TECHNICAL FIELD The present invention relates to a wakefulness detection device that determines a wakefulness by detecting a skin potential of a human body.

[Prior Art] Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 60-139539, there is a device in which a human body is equipped with a means for detecting skin potential and awakening or sleep of a person is detected by this skin potential. .

Focusing on the fact that there is a difference in skin potential (hereinafter referred to as SPL) between wakefulness and sleep, it is configured to determine to fall asleep when the SPL falls below a predetermined value.

[Problems to be Solved by the Invention] By the way, in general, a biological signal has individual differences or diurnal variations, and SPL also has diurnal variations.

In the above-mentioned technique, in order to cope with these individual differences and daily fluctuations, a sleep experiment is performed in advance to determine a predetermined value for determining sleep fall.

However, with this method, the user is forced to perform a sleep experiment, which greatly impairs the ease of use of the device.

Further, according to the above-mentioned method, it is possible to deal with a steady individual difference to some extent, but there is almost no effect of dealing with the daily fluctuation of each individual.

The present invention, when a person receives some kind of environmental change (stimulation),
Skin potential response (hereinafter S
PR) appears, and the appearance of this SPR is closely related to the arousal level, and it is an object to solve the problems of the above-mentioned conventional techniques. It is an object of the present invention to prevent an erroneous determination even if a signal fluctuation occurs, and to provide a more excellent awakening degree detection device.

[Means for Solving the Problems] Claim 1 according to the present invention made to solve the above problems, as shown in FIG. 1, is a skin potential detecting means for detecting the skin potential of a human body and the skin. A potential fluctuation detecting means for detecting a temporary fluctuation of the skin potential detected by the potential detecting means, and an awakening degree judging means for judging the arousal level based on the upward fluctuation detected by the potential fluctuation detecting means. And the awakening degree determination means is configured to start the determination after a predetermined time has elapsed since the detection means was attached to the human body.

According to a second aspect of the present invention, there are provided a skin potential detecting means for detecting a skin potential of a human body, a potential fluctuation detecting means for detecting a temporary fluctuation of the skin potential detected by the skin potential detecting means, and the potential fluctuation detecting means. And the skin potential detected by the potential fluctuation detecting means is set to a value lower than the reference value when the skin potential detected by the When it is less than the pressed determination value is determined, the skin potential detecting means is determined to be in a pressed state, and the awakening determination inhibiting means for inhibiting the determination by the awakening degree determining means is provided. To do.

According to a third aspect of the present invention, there are provided a skin potential detecting means for detecting a skin potential of a human body, a potential fluctuation detecting means for detecting a temporary fluctuation of the skin potential detected by the skin potential detecting means, and the potential fluctuation detecting means. As a reference value the skin potential after convergence of the temporary fluctuation detected by the, based on the change in skin potential by the skin potential detection means with respect to this reference value, awakening degree determination means for determining the awakening degree, When the skin potential detected by the potential fluctuation detecting means is lowered, it is provided with a reference value update prohibiting means for prohibiting updating of the reference value even when a temporary fluctuation occurs. And

According to a fourth aspect of the present invention, there are provided a skin potential detecting means for detecting a skin potential of a human body, a potential fluctuation detecting means for detecting a temporary fluctuation of the skin potential detected by the skin potential detecting means, and the potential fluctuation detecting means. As a reference value the skin potential after convergence of the temporary fluctuation detected by the, based on the change in skin potential by the skin potential detection means with respect to this reference value, awakening degree determination means for determining the awakening degree, Until the reference value is set, an initial reference value setting means for setting the initial value of the skin potential as the initial reference value is provided.

[Operation] The arousal level is detected based on the fluctuation of the skin potential by the skin potential detecting means, but the skin potential may become an unstable detection signal due to individual differences, diurnal variations, and handling of the device. According to each aspect of the present invention, it is possible to reliably determine the arousal level even with the unstable signal of the skin potential described above.

That is, the awakening degree determination means of claim 1 is configured to start the determination after a predetermined time has elapsed since the skin potential detection means was attached to the human body. Therefore, since the determination is not performed before the detecting means is adapted to the skin, it serves to avoid erroneous determination during this period.

According to the awakening degree determining means of the invention of claim 2, when the skin potential is lower than the reference value, it is determined that the awakening degree is lower, but the skin potential is lower than the pressure determination value set lower than the reference value. When it does, the determination of the decrease in arousal is prohibited. This serves to prevent the erroneous determination of the awakening degree due to the decrease in SPL at the time of pressing.

Further, in the awakening degree determination means of claim 3, the skin potential after the temporary fluctuation of the skin potential converges is used as a reference value, and the reference value is sequentially updated by the temporary fluctuation, so that the diurnal fluctuation can be dealt with. However, the reference value update prohibiting means prohibits the update of the reference value even if a temporary fluctuation occurs while the skin potential is lowered. That is, in consideration of the fact that the arousal level is low even when SPR occurs when the skin potential is decreased, the update of the reference value is prohibited so that the detection of the decreased arousal level is not delayed. .

In the invention of claim 4, the reference value for the determination of the skin potential is the stable value after SPR, but immediately after starting the SP
Although R may not appear, the initial reference value setting means sets the initial value of the skin potential as the reference value, so that the determination of the arousal level is prevented from being impossible or delayed.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

This embodiment is mounted on a vehicle to notify the driver of the decrease in arousal level by detecting a decrease in the awakening level of the driver of the vehicle, and controls the car earphone to wake up the driver's drowsiness. .

FIG. 2 is a block diagram showing the configuration of a doze detecting device using the present invention.

Reference numerals 1a and 1b are SPL detection electrodes, which are detection electrodes that are attached to the forearm and the ball of the subject by paste or the like (see FIG. 3), and are biological electrodes such as silver / silver chloride electrodes. is there. 2 is a detection circuit, which is the detection electrodes 1a and 1b
The SPL of the ball of the palm of the hand to the forearm derived from the above is differentially amplified and amplified to several V order. Reference numeral 3 denotes an awakening degree calculation unit, which includes an A / D conversion unit 3a that converts an analog SPL signal into a digital signal and a microcomputer 3b that executes a calculation process described later.

Reference numeral 4 is a buzzer and 5 is an air conditioner control device. It is a 6-car air conditioner and includes an inside / outside air switching device 6a, a blower 6b, an evaporator (cooling heat exchanger) 6c, a compressor (refrigerant compressor) 6d, a heater (heating exchanger) 6e, an air mix damper 6f, a bypass damper 6g, a bypass. The servo motor 6h and the bypass outlet 6i are included. Here, the bypass outlet 6i is open toward the driver's face.

Next, the operation of each component shown in FIG. 2 according to the first embodiment will be described. Power is supplied to the vehicle drowsiness alarm device of FIG. 2 by operating the ignition key switch of the vehicle, and the drowsiness detection process is executed by the microcomputer 3b.

Then, the buzzer 4 sounds by the decrease signal indicating the decrease in the arousal level output from the microcomputer 3b to notify the driver of the decrease in the arousal level and encourage the driver to take a break. In addition, the air conditioner control device 5 responds to the lowering signal output from the microcomputer 3b, to the blower 6b and the compressor 6d.
And the bypass servomotor 6h causes the bypass damper 6g to be opened to blow out cool air from the bypass outlet 6i toward the driver's face. This causes the driver to fall asleep.

Next, the awakening degree evaluation principle of the present embodiment will be described. FIG. 4 is a graph showing changes in SPL during vehicle operation. As shown in FIG. 4, the SPL at the early stage of vehicle operation is maintained at a high level, and the SPR is sensitive to environmental changes (stimulation) such as conversation and overtaking of a truck. However, about 1 hour after the start of the operation, the SPL is gradually reduced due to familiarization with the operation and the operating environment. Then, at this time, the SPR due to the environmental change, which often occurs when the SPL is at a high level, does not occur, and the SPL decreases in a toothed shape.

A detailed examination of the changes in SPL shown in this way shows that
It can be seen that the SPL after the occurrence of the SPR always returns to a substantially constant value. Also, after a long time has passed from the start of operation, SP
If SPR occurs even if L becomes low level, this SPL
Therefore, it can be said that the SPL after the SPR occurs reflects the high awakening level of the driver at that time. Therefore, the SPL after the occurrence of the SPR is stored as a reference value for the calculation of the SPL decrease rate, and this reference value is updated each time the SPR occurs, so that the awakening can be performed without being affected by the diurnal variation of the SPL and individual differences. It is intended to judge the deterioration of the degree.

As for SPR, as shown in FIG. 5, it can be seen that −V ₁ / t ₁ is larger than −V ₂ / t ₂ due to the decrease in SPL due to diurnal fluctuation and decrease in arousal level. Therefore, this −V / t is the threshold value T
If larger, it can be determined that SPR has occurred.

Further, in this embodiment, various measures are taken to prevent erroneous determination due to unstable output of various SPLs.

Next, the operation of the microcomputer 3b according to this embodiment will be described. 6A to 6C are flowcharts showing the operation of the microcomputer 3b according to this embodiment.

This process is executed at a sampling cycle of 1 second.
In the following description, the value of SPL takes a negative potential, but here, in order to simplify the description, the magnitude relationship will be described by its absolute value. First, in step 100, the internal RAM of the microcomputer 3b is cleared,
After performing initial settings such as setting various flags, the process proceeds to the next step 105. In step 105, SPL is read from the A / D converter 3a. The SPL is sampled every cycle, that is, once every second. In the following step 110, it is determined whether or not the value of SPL is continuous for 5 seconds within the range of normal data of 0 to 100 mV, and in the case of a negative determination, the sampling is executed again and the positive determination is made. In the case of, the buzzer sounds twice with a short sound of 4 Hz, and the flag indicating the normal time is turned on. This flag is for skipping the process of step 110 from the next time. In addition, this buzzer is performed only once after starting. Then, in step 115, Y
A flag determination is made as to whether or not the minute (for example, 2 minutes) timer is activated. In the first processing, a negative determination is made, so the Y minute timer is activated in step 120, and then the routine proceeds to step 125. In step 125, it is determined whether or not the SPL value is abnormal data for 5 consecutive seconds. If abnormal, the Y minute timer is turned off in step 130 and the Y minute time-up flag is set. Is turned off and the process is restarted from step 100 of initialization.

On the other hand, when it is determined in step 125 that the SPL value is not abnormal data for 5 consecutive seconds, step 1
At 35, the Y minute time-up flag is determined. This determination process is a determination as to whether or not Y minutes have elapsed since the start of measurement. When Y minutes have not elapsed, the process returns to step 105, and when Y minutes have elapsed, the step of FIG. 6 (B) is performed. Move to 140. The processing of step 135 is to wait until the value of SPL after mounting the detection electrodes 1a and 1b is stabilized, which will be described later. Therefore, from step 105 to step 1
The Y minutes up to 35 is a waiting time for preventing an erroneous determination at the initial stage, and the analysis of a decrease in arousal degree described later is not performed.

In the next step 140, the −V / t calculation described in FIGS. 4 and 5 is performed, and in the following step 145, the SPR is detected by comparing the −V / t calculated in step 140 with the threshold T. To do. Here, assuming that SPR has not occurred, the routine proceeds to step 150. In step 150, the SPR flag is determined. Since the flag has not been turned on yet, the process proceeds to step 155, and the reference flag indicating whether or not the reference value is set is determined. Even in this determination process, since SPR does not appear and the reference value is not set, in step 160 and subsequent steps, a temporary reference value setting process and a low SPL that replace the reference value setting process after SPR has occurred are performed. The determination process of the awakening degree in the level is executed. That is, in step 160, the initial good flag is determined, but in the first process, since the flag is not turned on, the process proceeds to step 165. In step 165, the SPL detection level is a predetermined value a (for example, 25 m
v) or more, and if the SPL value is the predetermined value a or more, the process proceeds to step 170, the SPL value at that time is stored, and the number of times of storage n is incremented, Further, in the following step 175, it is determined whether or not the number of times of storage n reaches Q (for example, 5 times). Since a negative determination is made in the first determination processing of step 175, the initial good flag is turned on at step 180, and when the predetermined number of times Q is reached, at step 185, the average value of the SPL values of Q times is temporarily set. After setting the reference value and setting it as the reference value, a reference flag indicating that the reference value has been set is turned on. The setting of the temporary reference value will be described later.

On the other hand, when it is determined in step 165 that the SPL value is equal to or less than the predetermined value a, in step 190, the average value of the sampled Q times (5 times) of the SPL value is calculated, and the calculated value is calculated. Memorize This process is performed a predetermined number of times SP as in the processes of steps 170 and 175 described above.
This is done by averaging the L values. Next Step 195
Then, the low awakening degree flag is determined, and if the flag is not turned on, the W minute (for example, 25 seconds) time-up flag is determined in step 200, and further, it is determined in step 205 that the flag is off. Start the W minute timer at. Then, when it is determined in step 200 that the W minute time-up flag is ON, that is, when it is determined that W minutes have elapsed after the calculation of the average value of the SPL values, the previous data of the SPL average value is calculated in step 210. If there is no previous data, step 2
At S30, the current data of the SPL average value is set to the previous data of the SPL average value. On the other hand, if the previous data is already set, at step 215, the previous data of the SPL average value and the current data are set. It is determined whether or not the difference is within a predetermined range ± b (for example, 1 mV). In this determination process, when the value is within the predetermined range b, a reduction signal for warning the reduction of the awakening degree is output in step 220 to output the buzzer 4
Sound for 5 seconds. After that, turn on the low alertness flag,
In step 230, the current data of the SPL average value is set as the previous data of the SPL average value. On the other hand, if the difference between the previous data and the current data is outside the predetermined range b in step 215, the low awakening degree flag is turned off in step 235, and the W minute time-up flag is further set in step 240. Turn off. The reason for performing this processing will be described later.

As a method of calculating the SPL average value (step 190), when the value of SPL is out of the range of 0 to 100 mV, the value may be ignored and the average value may be calculated using only other values. Further, when the value out of the range is three or more times among the values of SPL of 5 times, it may be determined that there is no SPL average value and the previous SPL average value may be used. This works so as not to update the SPL average value and the reference value with respect to a minute fluctuation value, and thus also effectively works to remove noise generated between the electrode and the skin.

Then, after the power is turned on, the first SPR is performed in step 145.
If it is detected, the routine proceeds to step 250, where the SPR flag is judged. However, since it is judged here that the SPR flag is not turned on, the SPR flag is turned on at step 255. This SPR flag is a flag that is turned on each time SPR occurs. Then, the process proceeds to step 150, and the SPR flag is determined. Since the SPR flag is turned on in step 255 here, the process proceeds to step 260 and the subsequent steps to set and update the reference value. First, in step 260, the stability flag is determined. The stability flag is a flag indicating that the SPL value after the SPR has been generated has stabilized within a predetermined range.
When it is determined at 65 that the SPL is stable, it is turned on at step 270. If the stability flag is turned on, the process proceeds from step 260 to step 285 to store the reference value calculation data based on the value of SPL and to count up the number of times the stored value is taken in, and then in step 290. When it is determined that the SPL value has been fetched a predetermined number of times P, in step 295 a stable SPL is calculated by averaging the stored values. Continued Step 29
At 8, it is determined whether or not the stable SPL is equal to or greater than the predetermined value a, and if the determination is affirmative, the determination of the reference flag in step 300 is performed. If the flag is not turned on, stable SPL is set as a reference value in step 305, the reference flag is turned on, and Z minutes (for example, 10
Min) Reset the timer. On the other hand, when the reference flag is turned on, the reference value already set in step 310 is compared with the stable SPL, and further step 31
5, stable SPL and a predetermined value X (for example, 0.
7 or 0.8) is compared with the pressing determination value. Here, when it is determined in step 310 that the stable SPL is larger, the updating process or the like using the stable SPL as a reference value is performed in step 305 described above, while the stable SPL is the reference value and the press determination value. If it is determined that the Z minute timer has timed out in step 320, it is determined in step 320.
5 or return to step 105, and when it is determined that the stable SPL is smaller than the pressing determination value, step 32
The process proceeds to the pressing flag determination process of No. 5. That is, once the reference value is set, the stable S value larger than the reference value is set.
When PL appears, the reference value is unconditionally updated with the stable SPL, but when stable SPL smaller than the reference value appears, the reference value is not updated unless Z minutes have elapsed. The reason for this will be described later. In addition, stable SPL is performed in step 315.
When is smaller than the pressing determination value, the pressing flag is determined and the pressing flag is turned on (described later) in steps 325 and 330.

If a new SPR is generated during this process (step 145), step 250 is followed by step 3
By 35, n reference value calculation data are cleared, and a process for newly obtaining a stable SPL is executed.

Next, a process for determining a decrease in arousal level after setting the reference value will be described. When it is determined in step 155 that the reference flag is turned on, the reduction rate is calculated by the following equation (1) in step 400.

Decrease rate = current SPL / reference value (1) In the following step 405, it is determined whether the above-mentioned decrease rate is larger than a predetermined value X, it is determined that it is smaller, and the flag is turned on by the determination of the pressing flag. If not (step 410), a drop signal is output and the buzzer is sounded (step 420). That is, when the value of SPL falls below X, it is determined that the awakening degree has decreased and the buzzer sounds for 5 seconds. On the other hand, when the value of SPL exceeds the predetermined value X in step 405, the pressing flag is turned off in step 425, and this processing ends.

The processing shown in this flowchart includes the characteristic processing described below.

First, in step 135, after the detection electrodes 1a and 1b are attached, the process waits for Y minutes (2 minutes) and then step 14
Processing of 0 or less is being executed.

The reason why this process is added will be described with reference to FIG. In the figure, SPL (A) (solid line) shows the measurement result when the measurement is started at the same time when the detection electrodes 1a and 1b are attached.
The measurement result when a sufficient time has elapsed after the electrode is attached is shown by SPL (B) (broken line). As is clear from these results, both SPL (A) and SPL (B) show a decrease in value only by SPL (A), even though the measurement experiment was conducted in a situation where the arousal level did not decrease. I understood. It is considered that this is because the value of SPL decreases as the electrode and the skin get fit, and it takes a predetermined time for the value to stabilize. From this, the detection electrodes 1a, 1b
If the measurement is immediately started after wearing the SPL, the SPL may be reduced to 80% of the reference value, which may cause a false determination that the wakefulness is reduced. Focusing on these facts, the detection of the arousal level is prohibited until the predetermined time elapses after the detection electrodes 1a and 1b are attached as described above.

Further, in steps 160 to 185, S
Instead of setting the reference value before the occurrence of PR, a temporary reference value setting process based on the SPL average value is performed. That is,
As the reference value for determining the awakening degree reduction in this processing, the value of stable SPL after the appearance of SPR in the processing of steps 140, 260 to 320 is used. However, as shown in FIG. 8, there is little external stimulus and S immediately after the start of measurement.
Since the PR does not appear and the reference value is not set, the PR may not be detected even though the wakefulness is lowered.

Therefore, after the start of measurement, until the appearance of SPR, the stable SPL average value detected first is used as the temporary reference value.

In steps 195 to 240, the detection process of the awakening degree decrease for the case where the signal level of SPL is low (0 to 25 mV) is performed. That is, when the SPL average value decreases and the fluctuation in the predetermined range b or more disappears, the buzzer 4 gives a warning. This is because in the case of a low SPL signal level, it was possible to recognize that the arousal level had decreased when the SPL value decreased and reached a stable value, so the above-described determination processing was added. Of.

When the difference between the previous data and the current data of the SPL average value is outside the predetermined range b, the calculation of the SPL average value and the determination of the awakening degree are performed every 30 seconds, while the awakening degree is once determined to decrease. If SPL is reached, the SPL
The calculation of the average value and the warning by the buzzer are alternately repeated for 5 seconds until it goes out of the predetermined range b, whereby it is possible to accurately and continuously detect the decrease in arousal level and the warning.

SPR by steps 260 to 310
When the stable SPL after the occurrence of is larger than the reference value, the reference value is unconditionally updated. However, when the stable SPL is smaller than the reference value, the processing of step 320 causes Z minutes (10 minutes from the previous update). If the number of minutes has not passed, the reference value is not updated.

The reason why such processing is added will be described with reference to FIG. As shown in FIG. 9, when the value of SPL is decreasing with the passage of time, the reference value SPL ₁ is set at the time point t ₀ , and then SPR appears and is lower than the reference value SPL _1. When the stable SPL of the value is obtained at the time point t ₁ , and the value is set as the reference value SPL ₂ , the time when the reduction rate of the alertness is 80% is the time point t ₃ , and the reference value SPL ₁ is maintained. At the time of determination of the decrease in arousal level in t ₂
More late. However, if the SPL is decreasing,
When a stimulus is applied despite being half awake, S
Since the PR may appear, if the reference value is simply updated by the appearance of the SPR, the time point for determining the decrease in the arousal level may be delayed. Moreover, in particular, when the SPL lowering tendency continues, the reference value may be updated every time SPR occurs, and the determination of the lowering of the awakening degree may be extremely delayed.

Therefore, when the SPL shows a decreasing tendency, the reference value is not updated so that the warning of the decrease in the arousal level can be issued at least once within Z minutes. In order to cope with fluctuations such as a decrease, the standard value is allowed to change to a low level every Z minutes.

In the processing of steps 315 to 325, 410, etc., when the stable SPL is smaller than the pressing determination value (reference value × X) (step 315), the pressing flag is turned on (step 330) and the reference value is not updated. Not
Processing for avoiding the output of the signal for lowering the arousal level (step 41)
0, step 420).

This processing is added for the following reason. Second
As shown in FIGS. 3 and 4, the detection electrodes 1a, 1 are attached to the finger and the wrist.
In the embodiment in which b is mounted and SPL is detected, excessive pressure is applied to the finger electrodes when the steering wheel of the automobile is gripped. It was found that the SPL in this state drastically drops as shown in FIG. 10, and that state is maintained when the handle is continuously held. Therefore, the present processing is performed by adding the above-described processing so as not to be erroneously determined to be a decrease in awakening degree even when the steering wheel or the like is strongly gripped.

Here, when examining the difference between the decrease in the arousal level and the decrease in the pressed state, as shown in FIG. 11, in the pressed state, it takes 20 seconds or less before the SPL value decreases to 80%. , It was found to be shorter than the decrease in arousal level. From the above, the criterion for judging the decrease of the SPL value due to the pressure is the pressing judgment value lower than the reference value. Then, when the stable SPL becomes larger than the pressing determination value (step 405), the pressing flag is reset to return to the normal processing (step 425).

As a criterion for the pressed state, instead of the pressed determination value, for example, the SPL value before the appearance of SPR and the stable SPL after the appearance of SPR are compared, and the change for 20 seconds is a predetermined value or more (0.7 mV / s Etc.), it may not be determined that the awakening degree has decreased, and at this time, the buzzer may be sounded at the same time to warn the driver.

The following processing can be considered as a modification of the above embodiment.

(1) Instead of the process of using the reference value X (80% or 70%) as the criterion for the decrease in arousal level as in steps 405 to 420 of FIG. 6 (C), steps 190 to 240 will be described. You may use together the determination process of the low level signal's awakening degree reduction. That is, the SPL average value is lower than the reference value × X, and the previous SPL average value and the current SPL average value are
When the difference from the PL average value is ± 1 mV, a warning is given for 5 seconds, and the determination of the awakening degree and the warning are repeated until the difference is out of the range.

(2) As a condition for updating the reference value, there is SPR three or more times per minute, and the stable SPL after that is
You may add the condition that it is 90% or more of the already set reference value. As a result, it is possible to more harmonize the detection delay of the decrease in arousal level with the effect of diurnal variation.

Although the embodiments and the modifications thereof to which the present invention is applied have been described above, the present invention is not limited to these.

For example, as another embodiment, a wakefulness detecting device that consumes less power and is battery-powered and portable will be described.

That is, the characteristic configuration of this device is shown in the block diagram of FIG. 12, and an amplifier 20 connected to the detection electrodes 1a and 1b and a voltage from the amplifier 20 is converted into a frequency. V / F section 22 for inputting to computing section 3b
A differential circuit 24 that outputs a differential signal based on the signal from the amplifier 20; and an operation start circuit 26 that starts the operation unit 3b based on the output signal from the different circuit 24 and the time-up signal from the timer circuit 28. Is equipped with. In the above configuration, the SPLs from the detection electrodes 1a and 1b are amplified by the amplifier 20, converted into a frequency signal by the V / F unit 22 and input to the arithmetic unit 3b, and the differentiation circuit 24
Is also entered directly. When the differentiating circuit 24 detects the detection of SPR based on the signal from the amplifier 20, it sends a signal to the arithmetic unit activating circuit 26 to activate the arithmetic unit 3b.
The arithmetic unit 3b is intermittently activated by the timer circuit 28 at regular intervals except when the SPR is detected by the differentiating circuit 24.

The operation of this device will be described with reference to the flowchart of FIG. 13. First, step 500 shows that the initial process is executed. This process corresponds to steps 100 to 135 in FIG. 6 (A). The following steps 510 and 520 show that the arithmetic unit 3b is activated via the arithmetic unit activation circuit 26 when SPR is detected based on the signal of the differentiating circuit 24. Then, when the arithmetic unit 3b is activated, step 5
A reference value setting process is executed at 30 and the following step 54
At 0, the timer circuit 28 is reset by the signal from the arithmetic unit 3b. Then, when these processes are completed, the arithmetic unit 3b is stopped in step 545. This processing corresponds to steps 145 and 150 and steps 260 to 335 in FIG. 6 (B).

On the other hand, while SPR does not appear, at step 550,
The timer circuit 28 determines whether or not the time is up within a predetermined time (for example, 25 seconds). When the time is up, the arithmetic unit starting process is performed in step 560,
SPL sampling (step 570), awakening degree calculation (step 580) and resetting of the timer circuit 28 (step 590) are performed, and then the calculation unit 3b is stopped (step 595). Here, the steps 570 and 580 correspond to steps other than the above-described initial processing and reference value setting processing in FIGS. 6 (A) to (C).

In addition, as a timer in the present embodiment, FIG.
(C) Y minute timer in step 115, step 205
The W minute timer, which is equivalent to the Z minute timer in step 320, is required. Among them, the Y minute timer and the Z minute timer have a time t from the detection of the SPR to the detection of the stable SPL. , A W minute timer or the like stores the number of times the flag is turned on when the time is up, and is configured as a simple timer that determines the sum of them. Then, the state of the flag set by the time-out of the simple timer is determined and various calculations are performed.

When the state of awakening detected by this device is shown in FIG. 14, for example, SPR appears at the beginning of measurement and the calculation unit 3b
In the state in which S is started for a long time and SPR does not appear, the calculation unit 3b is started for the sampling time Tb at the sampling interval ta.

Therefore, according to the above-described embodiment, the microcomputer is operated intermittently within the range that does not affect the detection of the arousal level, that is, the startup time of the microcomputer is shortened with respect to the total measurement time. The power consumption is reduced, so that when a battery is used, the service life can be extended, the battery can be downsized, and the degree of freedom in designing as a portable device can be increased.

Increasing the sampling interval performed intermittently is the maximum (ta-t
Since b) is brought about, it is decided in consideration of the time allowed as the detection delay of the awakening degree and the power consumption.

Further, the present invention is not limited to the detection of drowsiness in a vehicle, and can be applied to the detection of drowsiness in various kinds of work and work. It is appropriately changed according to the environment.

Further, the detection electrodes 1a and 1b and the detection circuit 2 shown in FIG. 3 can have various configurations. For example,
One detection electrode may be formed as a finger electrode and the other electrode may be formed as a wristwatch type.

Furthermore, in each of the above-described examples, the threshold value for detecting the decrease in arousal level from the fluctuation of SPL, the threshold value for detecting SPR, etc. may vary depending on the environment in which the subject is present and individual differences. It should be changed appropriately.

Further, in each of the above-mentioned embodiments, the buzzer or the car air conditioner is activated mainly due to the decrease of the arousal level, but the stop of the buzzer or the car air conditioner may be performed by a timer for a predetermined time, or the increase of the SPL. Or
You may detect and generate SPR.

In the various embodiments described above, the S
Although the awakening degree is determined based on the degree of decrease in SPL with respect to PL as a reference value, the awakening degree may be determined based on the frequency of occurrence of SPR.

[Effects of the Invention] As described above, according to the invention of claim 1, the judgment is started after a predetermined time has passed since the skin potential detecting means was attached to the human body. Detection can be prevented. Further, according to the invention of claim 2, when the skin potential is lower than the pressing determination value set lower than the reference value, the determination of the decrease in the awakening degree is prohibited, so that the awakening when the skin potential detecting means is pressed is awakened. It is possible to prevent erroneous determination of the degree. Further, according to the invention of claim 3, updating of the reference value is prohibited when a temporary fluctuation occurs while the skin potential is decreasing. Therefore, when the skin potential is slowly decreasing, It is possible to prevent delay in detection of a decrease in alertness. Moreover, according to the invention of claim 4, since the initial value of the skin potential is set as the reference value immediately after the activation, it is possible to solve the problem that the determination of the arousal level becomes impossible or delayed at the activation. In other words, the present invention has the remarkable effects that it is possible to appropriately cope with the daily fluctuations and the human characteristics by the above-mentioned configuration and to avoid erroneous detection with respect to various external factors. It is a thing.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a basic configuration of the present invention, FIG. 2 is a configuration diagram showing an awakening degree detection device according to an embodiment of the present invention, and FIG.
FIG. 4 is an explanatory view showing the mounting state of the detection electrode, FIG. 4 is a time chart showing the basic operation of the same embodiment, and FIG. 5 is SPR.
6 (A), (B), and (C) are flow charts according to the same embodiment, FIGS. 7 to 11 are graphs for explaining the operation of the same embodiment, and FIG. 12 is another graph. FIG. 13 is a configuration diagram showing a wakefulness detection device according to an embodiment, FIG. 13 is a flowchart of another embodiment, and FIG. 14 is a time chart of another embodiment. 1a, 1b ... Detection electrode, 2 ... Detection circuit 3 ... Awakening degree computing unit, 3a ... A / D converter 3b ... Microcomputer, 4 ... Buzzer 5 ... Air conditioner control device, 6 ... Car air conditioner SPL ... Potential (Skin Potential Lebel) SPR ... Skin Potential Lebel Responc
e)

Claims (4)

[Claims] 1. A skin potential detecting means for detecting a skin potential of a human body, a potential fluctuation detecting means for detecting a temporary fluctuation of the skin potential detected by the skin potential detecting means, and the potential fluctuation detecting means. And awakening degree determining means for determining the awakening degree based on the fluctuation detected by the above, and the awakening degree determining means starts the determination after a predetermined time elapses after the detecting means is mounted on the human body. An awakening degree detection device configured to perform. 2. A skin potential detecting means for detecting a skin potential of a human body, a potential fluctuation detecting means for detecting a temporary fluctuation of the skin potential detected by the skin potential detecting means, and the potential fluctuation detecting means. And the skin potential detected by the potential fluctuation detection means is set to a value lower than the reference value when the skin potential detected by the When it is less than the pressed determination value, it is determined that the skin potential detecting means is in the pressed state,
An awakening degree detection device comprising: an awakening determination inhibiting means for inhibiting the determination by the awakening degree determining means. 3. A skin potential detecting means for detecting a skin potential of a human body, a potential fluctuation detecting means for detecting a temporary fluctuation of the skin potential detected by the skin potential detecting means, and the potential fluctuation detecting means. As a reference value the skin potential after the temporary fluctuations detected by the convergence, based on the change in skin potential by the skin potential detection means with respect to this reference value, awakening degree determination means for determining the awakening degree, When the skin potential detected by the potential fluctuation detecting means is lowered, the reference value update prohibiting means for prohibiting the update of the reference value is provided even if a temporary fluctuation occurs. Awakening degree detection device. 4. A skin potential detecting means for detecting a skin potential of a human body, a potential fluctuation detecting means for detecting a temporary fluctuation of the skin potential detected by the skin potential detecting means, and the potential fluctuation detecting means. As a reference value the skin potential after the temporary fluctuations detected by the convergence, based on the change in skin potential by the skin potential detection means with respect to this reference value, awakening degree determination means for determining the awakening degree, An awakening degree detection device comprising: an initial reference value setting unit that sets an initial value of the skin potential as a reference value until the reference value is set.