JPH0314655B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a device that detects and warns the occurrence of drowsy driving based on the opening/closing status of the driver's eyelids. This invention relates to a driving detection device.

[Technical background of the invention and its problems] In recent years, various devices have been proposed to prevent drowsy driving and improve driving safety. For example, the dozing prevention device disclosed in Japanese Patent Application Laid-Open No. 127198/1983 is one of the devices for this purpose. This anti-drowsiness device uses glasses equipped with a means for transmitting electromagnetic waves to the wearer's eyes and a means for receiving reflected waves from the wearer's eyes, and transmits electromagnetic waves such as infrared rays to the eyelids and cornea of the eyes. By focusing on the fact that the level of reflected waves from the eyelids becomes higher when the waves are transmitted, it detects when the eyelids are closed, and if this state continues for a predetermined period of time, it determines that the person is dozing off and issues an alarm. . That is, by making the driver wear glasses related to this dozing prevention device, it is possible to detect dozing off while driving and warn the driver.

By the way, in the above-mentioned dozing prevention device, the wave transmitting means and the wave receiving means transmit electromagnetic waves to the wearer's eyes under the correct wearing condition, so that the waves reflected from the wearer's eyes can be obtained. It is installed on the mirror body. However, when a vehicle is running, vehicle vibrations occur due to various factors, and the driver inside the vehicle is also affected by this vibration to some extent, so it is important that the driver wears the product in the correct condition. There is a risk that the sleeping mirror placed on the driver's face may become misaligned with the driver's face, temporarily or unknowingly, due to the effects of vibration. In such a misaligned state, the electromagnetic waves transmitted from the wave transmitting means may not reach the driver's eyes and may be reflected elsewhere and return to the receiving means, or may be left untransmitted. There is a possibility that an incorrect situation may occur, and as a result, accurate detection may not be possible.

[Object of the Invention] The present invention has been made in view of the above, and has an object to include a means for transmitting electromagnetic waves to the wearer's eyes and receiving reflected waves by the wearer's eyes, A device that detects the opening and closing status of the driver's eyelids based on the difference in the level of waves reflected by the cornea of the eye and waves reflected by the eyelids, and detects and alerts the driver if he or she is dozing off based on the detection results, ensures the ability to detect dozing. To provide a reliable drowsy driving prevention device.

[Summary of the invention] In order to achieve the above object, in the device,
This invention includes an eye blink detection means that detects that the driver blinks based on the reflected wave and outputs a blink signal, and detects that the sleep mirror is not in the correct wearing state when the blink signal is not input for a predetermined period of time. The gist of the present invention is to provide a wearing state notification means that makes a judgment and gives an alarm.

[Embodiments of the Invention] Examples of the invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a drowsy driving prevention device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of this drowsiness driving prevention device. The components of this drowsy driving prevention device, which will be explained below with reference to FIGS. 1 and 2, are provided in a sleep mirror 1. A wave transmitting/receiving section 3 that transmits electromagnetic waves of a specific wavelength and receiving reflected waves from the wearer's eyes, and a sleep mirror 1 that drives and controls this wave transmitting/receiving section 3 and based on signals from the wave transmitting/receiving section 3. The control circuit box 5 is divided into a control circuit box 5 for detecting drowsiness of the driver, who is the wearer of the vehicle.

The wave transmitting/receiving unit 3 is provided near the frame bottom 7 that holds the lenses of the sleeping mirror 1, and includes a wave transmitting means 9 that transmits electromagnetic waves of a specific wavelength (for example, 900 nm) to the eyes of the wearer of the glasses 1. , a first wave receiving means 11 that receives reflected waves of the electromagnetic waves of a specific wavelength transmitted from the wave transmitting means 9 by the cornea or eyelids of the wearer's eyes; and an electromagnetic wave transmitted from the wave transmitting means 9. The second wave receiving means 13 receives electromagnetic waves in a wavelength band different from the wavelength band (for example, 1200 nm for detecting headlamp light). Wave transmitting means 9
The configuration includes a light emitting element 15 that outputs electromagnetic waves in a wavelength band near near-infrared light, and a transmitting narrowband filter 17 that passes only electromagnetic waves of the specific length (for example, 900 nm) among the output electromagnetic waves. It is.
The first and second wave receiving means 11 and 13 both include receiving narrowband pass filters 19 and 21 that pass only electromagnetic waves of specific wavelengths, and electromagnetic waves that have passed through the receiving narrowband filters 19 and 21, respectively. The configuration includes light receiving elements 23 and 25, respectively, which receive light and convert it into an electrical signal. Note that the light receiving elements 23 and 25 are composed of, for example, phototransistors.

The control circuit box 5 is connected to one vine 27 of the glasses 1.
, and is connected to the wave transmitting/receiving section 3 by a cord (not shown). The control circuit box 5 includes a drive circuit 29 connected to the light emitting element 15 to drive and control the light emitting element, and a drive circuit 29 connected to the light receiving elements 23 and 25 of the first and second wave receiving means 11 and 13 to drive and control the light receiving elements. It has a processing circuit 31 that processes the light reception signals from 23 and 25 to determine whether the driver has fallen asleep.

In the processing circuit 31, the output of the light receiving element 23 is connected to a non-inverting input terminal (+) of a comparator 35 via an amplifier 33. This comparator 35 has its inverting input terminal (-) connected in series between the power supply voltage Vcc and ground, and between a resistor 37 and a resistor 39 that divide the power supply voltage Vcc, and whose output is It is connected to an input terminal b of an AND circuit 41 and an input terminal a of an AND circuit 45 via a differentiating circuit 43. In the comparator 35, the divided voltage supplied to the inverting input terminal (-) is transmitted to the wave transmitting means 9.
This difference is set to become clear by focusing on the fact that the level of the electromagnetic waves reflected by the eyelids is higher than the level of the waves reflected by the cornea, so that the received light signal is higher than the divided voltage. The sensor outputs a high level (H) signal upon detecting that the received light signal is a reflected wave from the eyelids (that is, the eyes are closed).

On the other hand, in the processing circuit 31, the light receiving element 25
The output amplifier 51 is connected to the non-inverting input terminal (+) of the comparator 53. This comparator 53
is connected in series between the power supply voltage Vcc and ground, and between resistors 55 and 57 that divide the power supply voltage Vcc, and its output is connected through an inverter 59. It is connected to input terminal b of the AND circuit 45 and input terminal c of the AND circuit 41. In this comparator 53, the divided voltage supplied to the inverting input terminal (-) is transferred to a transmitting means such as a headlamp of an oncoming vehicle so that the electromagnetic wave level in the vicinity of near infrared rays in the vicinity of the wave transmitting/receiving section 3 is The electromagnetic waves transmitted from the driver's eyelids are set to be able to determine whether the level of the electromagnetic waves is high enough to affect the level of the reflected waves by the cornea or eyelids of the driver's eyes. It detects that the level is high enough to affect the reflected waves by the cornea or eyelids of the eye and outputs a high level (H) signal. Note that instead of providing the circuit from the second wave receiving means 13 to the comparator 53 described above, a vapor-deposited film of a filter is coated on the lens surface of the glasses 1 in order to block external electromagnetic waves in the near-infrared region. Good too.

The AND circuit 41 has input terminals b and c connected to the output of the comparator 35 and the output of the comparator 53 via the inverter 59, respectively, as described above, and an input terminal a connected to the oscillator 47. , and its output is connected to the clock input terminal c _L of the counter circuit 48. That is, this AND circuit 41 is in a state where the comparator 35 outputs a high level (H) signal and the comparator 53 outputs a low level (L) signal, in other words, near the wave transmitting/receiving section 3. When the background level of electromagnetic waves in the near-infrared region is below a predetermined level and it is detected that the electromagnetic waves transmitted from the wave transmitting means 9 are reflected by the driver's eyelids, the oscillator 47 generates a predetermined signal. Pulses output at time intervals are supplied to the clock terminal _cL of the counter circuit 48.

As described above, the counter circuit 48 measures the time during which the driver's eyelids are closed by counting the pulses from the oscillator 47 supplied when the driver's eyelids are closed, and this count value reaches a predetermined value. When the driver's eyelids have been closed for a predetermined period of time (for example, 2 seconds), the system determines that the driver is drowsy while driving.
An alarm command signal is output to the alarm drive circuit 49 connected to the output to drive the alarm speaker 50. Note that since the output of the counter circuit 48 is connected to the reset terminal R of the counter circuit 48, the count value of the counter circuit 48 is reset at the same time as the alarm command signal is output.

On the other hand, the AND circuit 45, as described above,
In addition to the fact that the input terminals a and b are connected to the output of the comparator 35 via the differentiating circuit 43 and the output of the comparator 53 via the inverter 59, the output is connected to the reset terminal R of the counter circuit 61.
It is connected to the. This counter circuit 61 has its clock input terminal _cL connected to the oscillator 47, and its output terminal connected to the warning speaker 65 via the warning driving circuit 63. Time is measured by counting the supplied pulses, and when the counted value reaches a predetermined value without a reset signal being supplied to the reset terminal R, the warning drive circuit 6
3 outputs a notification command signal to drive a warning speaker. That is, the AND circuit 45 operates when the output of the comparator 53 is low level (L),
In other words, the output of the comparator 35 rises from a low level (L) to a high level (H) when the background level of electromagnetic waves in the near-infrared region near the wave transmitting/receiving section 3 is below a predetermined level. Time,
In other words, when it is detected that the driver's eyelids are closed, the pulse generated by the differentiating circuit 43 is outputted to the reset terminal R of the counter circuit 61 as the reset signal. For this reason, the counter circuit 61 determines that the eyeglasses 1 are not in the correct wearing state and notifies the wearer when this eyelid closing action (blink) is not detected for a predetermined period (for example, one minute). Note that the notification in this case does not need to be a signal with a level as high as the alarm sound that is output during drowsy driving, so the warning notification drive circuit 63 may use a melody, for example.
Consists of IC, etc.

Next, the operation of this embodiment will be explained.

When the driver puts on the glasses 1 at the start of driving, the light emitting element 15 emits light from the wave transmitting means 9 under the control of the drive circuit 29, and electromagnetic waves of a specific wavelength are transmitted to the driver's eyes via the wave transmitting narrowband filter 17. is transmitted. This transmitted electromagnetic wave is reflected by the cornea when the driver's eyelids are open, and reflected by the eyelids when the driver's eyelids are closed. The first and second waves are reflected as reflected waves along with the light reflected by the eyelids.
to the wave receiving means 11 and 13. In the first wave receiving means 11, out of this reflected wave, the wave transmitting means 9
After extracting only the same specific wavelength component as the electromagnetic wave transmitted from the light receiving element 2 by the receiving narrow band filter 19,
Receives light at 3. On the other hand, in the second wave receiving means 13, among the reflected waves, wavelength components different from the electromagnetic waves transmitted from the wave transmitting means 9 to measure the level of the external light are filtered through the receiving narrow band filter 21. After extraction, the light is received by the light receiving element 25.

The light receiving element 23 photoelectrically converts the received electromagnetic wave into a received light signal, which is amplified by the amplifier 33 and sent to the comparator 3.
Output to 5. Comparator 35 compares the level of this light reception signal with the voltage level divided by resistors 37 and 39, and outputs a high level (H) signal when the level of the light reception signal is high. That is, in this comparator 35, the level of the electromagnetic wave reflected by the eyelids of the electromagnetic wave transmitted from the wave transmitting means 9 with the divided voltage supplied to the inverting input terminal (-) is higher than the level of the reflected wave by the cornea. Since the setting is made so that this difference becomes clear by paying attention to the fact that the difference occurs, it detects that the received light signal is a reflected wave from the eyelids and outputs a high level (H) signal. This high level (H) signal is sent to the AND circuit 4.
Since it is output to the input terminal b of 1 and triggers the differentiating circuit 43 at the rising edge of the rising edge, the differentiating circuit 4
3 uses this trigger to generate a pulse signal with a predetermined time width.
Output is output to input terminal a of AND45.

On the other hand, the light receiving element 25 photoelectrically converts the received electromagnetic wave and outputs it to the comparator 53 after being amplified by the amplifier 51 as a received light signal. Comparator 53 compares the level of this light reception signal with the voltage level divided by resistors 55 and 57, and outputs a high level (H) signal when the level of the light reception signal is high. In this comparator 53, the electromagnetic wave level in the near-infrared region around where the wave transmitting/receiving section 3 is provided is applied to the divided voltage supplied to the inverting input terminal (-). The electromagnetic waves transmitted from the driver's eyelids are set to be able to determine whether the level of the electromagnetic waves is high enough to affect the level of the reflected waves by the cornea or eyelids of the driver's eyes. If the level is high enough to affect the waves reflected by the cornea or eyelids of the eye, a high level (H) signal is output. This high level (H) signal is inverted by the inverter 59 and then
Input terminal b of AND circuit 45 and AND circuit 41
is output to input terminal c of. That is, this second
In the circuit from the wave receiving means 13 to the inverter 59, the level of electromagnetic waves in the near-infrared region around the wave transmitting/receiving section 3, so to speak, the background level is high in order to accurately detect drowsy driving or the wearing state of the glasses 1. In order to prevent detection in this state, a low level (L) signal is output to the AND circuits 41 and 45, so that the necessary signal is not supplied to the circuit for carrying out the detection.

The AND circuit 41 has input terminals b and c in a high level (H) state, that is, as described above, the wave transmitting/receiving section 3
When the surrounding background level is not higher than a predetermined level and a reflected wave from the driver's eyelids is being obtained, the oscillator 47 outputs a pulse signal at regular time intervals to the counter circuit 48. When the counter circuit 48 counts the supplied pulses and reaches a predetermined value, that is, when the driver's eyelids remain closed for a predetermined period of time, the counter circuit 48 determines that the driver is dozing and issues an alarm. Outputs a command signal. The alarm drive circuit 49 receives this alarm command signal and operates the alarm speaker 50 to wake up the driver.

Further, the AND circuit 45 receives the pulse signal output from the differentiating circuit 43 when the input terminal b is at a high level (H), that is, when the background level around the wave transmitting/receiving section 3 is not higher than a predetermined level as described above. It is output as a reset signal to the reset terminal R of the counter circuit 61. The counter circuit 61 normally generates an oscillator under reset control each time it is supplied with a reset signal from the differentiating circuit 43, that is, a signal generated when the driver's eyelids change from an open state to a closed state. The counting operation of pulse signals from 47 continues. During such a counting operation, if the reset signal is not supplied for a predetermined period of time or more, in other words, humans normally perform an instantaneous blinking operation of about 0.5 seconds or less in an awake state, but as part of this blinking operation, If the action of closing a certain eyelid cannot be detected for a predetermined period of time or more, the counter circuit 61 determines that the glasses 1 are not correctly worn and outputs a warning command signal. Warning drive circuit 63
In response to the command signal, the warning speaker 65
to prompt the driver to correctly wear the glasses 1.

[Effects of the Invention] As explained above, there is a means for transmitting electromagnetic waves to the wearer's eyes and receiving the waves reflected by the wearer's eyes, and the means for transmitting electromagnetic waves to the eyes of the wearer and receiving the waves reflected by the eyes of the wearer is provided. In a device that detects the opening and closing status of the driver's eyelids based on the difference in level, and detects and alerts the driver when the driver falls asleep based on the detection results, if the driver's blinking action cannot be detected for a predetermined period of time, the glasses are not properly worn. Since it is determined that there is no such event and the driver is notified of this, it is possible to ensure the detection of drowsy driving, thereby making it possible to prevent the occurrence of drowsiness from being overlooked and from generating false alarms.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of a drowsy driving prevention device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a circuit configuration of the drowsiness driving prevention device according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Glasses, 3... Wave transmitting/receiving unit, 5... Control circuit box, 9... Wave transmitting means, 11... First wave receiving means, 13... Second wave receiving means, 29... Drive Circuit, 31...Processing circuit, 41...AND circuit, 4
3...Differential circuit, 45...AND circuit, 47...
Oscillator, 48...Counter circuit, 49...Alarm drive circuit, 50...Alarm speaker, 61...Counter circuit, 63...Warning drive circuit, 65...
...Warning speaker.

Claims (1)

[Claims] 1 It has means for transmitting electromagnetic waves to the wearer's eyes and receiving the waves reflected by the wearer's eyes, and detects the opening and closing of the driver's eyelids based on the difference in the level of the waves reflected by the cornea of the eye and the waves reflected by the eyelids. A device that detects a situation, detects a driver's drowsiness based on the detection result, and issues an alarm, comprising: a blink detection means that detects a blink of the driver based on the reflected wave and outputs a blink signal; A device for preventing drowsy driving, comprising a wearing state notification means that determines that the glasses are not in the correct wearing state and issues an alarm when a blink signal is not input for a predetermined period of time.