Patent Application
20150351702
The present invention relates to a technique to detect drowsiness of a human.
JP 2011-123653 A (PTL 1) discloses a background art of this technical field. As stated in this publication, “. . . assesses the driver's arousal level based on data obtained from the temperature of the facial skin, the temperature of the finger skin and the pulse rate, each being measured, and on each assessing threshold value” (refer to Solution to Problem).
PTL 1: JP 2011-123653 A
Drowsiness of a human may be caused by an underlying disease such as sleep apnea syndrome in some cases, but not in other cases. Regardless of the cause, drowsiness occurring during driving of a vehicle or the like may in some cases lead to a serious accident involving loss of life. Furthermore, drowsiness has already led to heavy economic losses. Therefore, there is a need for a technique to detect drowsiness (before falling asleep) with such a high accuracy as to classify the drowsiness into levels, and prevent accidents and ensure safety by taking measures corresponding to each level.
The known technique in the above publication may be able to detect a fixed level of drowsiness to assess the drowsiness based on the preset assessing threshold; however, it is difficult to detect the drowsiness with high accuracy.
To solve the above-described problem, configurations as described in CLAIMS are adopted, for example.
The present application includes a plurality of means for solving the above-described problem, and provides an exemplary means for assessing a drowsiness level of a living body by calculating the drowsiness level based on a core body temperature and a surface temperature in a peripheral region of the living body.
Detecting drowsiness with high accuracy makes it possible to prevent accidents caused by drowsiness. As a result, safety for humans and society can be achieved and economic loss can be reduced.
Embodiments will be described below with reference to the drawings.
In the present embodiment, an exemplary in-vehicle drowsiness detection apparatus (100) will be described.
A temperature measurement unit (102) for measuring the temperature of a human hand (101) may be attached to a surface or an inner portion of a steering wheel (103), or to the human hand. Alternatively, a non-contact temperature sensor may be installed in a vehicle or the inner portion of the steering wheel, or mounted on the shift lever. Therefore, techniques in the embodiment are merely exemplary and non-limiting. In use of the sensor attached to the human hand (101), data may be transmitted to a data processing/drowsiness level assessing unit (104) using a radio wave or the like, other than using a cable.
The temperature measurement unit (102) may be separated into a fingertip temperature measurement unit (105) and a palm temperature measurement unit (106). Another possible technique is to provide a temperature sensor on one surface; the sensor portion to be used for the measurement is determined using a pressure sensor to detect a hand touch. According to the drowsiness level calculated by the data processing/drowsiness level assessing unit (104), an information presentation unit (107) is functionally configured and includes a stimulus presentation unit (201) and an alarm presentation unit (202). The information presentation unit (107) presents a stimulus to alert a driver, or presents an alarm to the driver and outside the vehicle. A technique using the information presentation unit (107) in conjunction with a vehicle navigation system is effective, but non-limiting. The stimulus and alarm as described above may be presented as voice, or visual information such as a character, an image, and a video presented on a display. As a stimulus, cool air can be blown in conjunction with an air conditioner. Other techniques include generating fragrance. Examples of fragrances known to have alertness effects include rosemary, peppermint, and tea tree. An effective technique to use essential oils having alertness effects may be to provide essential oils in a bottle or provide fragrance components such as essential oil on a tray, to be placed at an air conditioning outlet in advance. When a driver needs to be alerted, air from the air conditioner containing fragrance components may be blown with this technique. An alarm to the outside of a vehicle may be implemented by reporting to an external institution on a radio wave or the like, by flashing a hazard lamp, or by using a message board such as an electronic bulletin board installed inside or outside the vehicle. An alarm can be displayed in conjunction with a destination screen or a passenger status screen when the vehicle is a bus.
An exemplary method of detecting drowsiness in a vehicle will be described specifically below by using a flowchart in
When peaks are lost in a palm and one peak is detected in a fingertip, the assessment is drowsiness level 2 (high-level drowsiness), and then, the status goes on to a stimulus presentation for alertness and an alarm presentation (306) including a call for a replacement driver. When a peak is detected in both a palm and a fingertip, peak heights (absolute values) and/or time intervals of the peaks can be used for the assessment. In the assessment using peak heights, the peak height lower than a preset threshold is assessed as drowsiness level 1 (medium-level drowsiness). In this case, stimulus presentation (310) is performed while a processing flow on and after the temperature measurement is repeated to confirm the effectiveness of the stimulus presented. The difference in the forms of the peaks can be used in this manner to analyze the drowsiness level with higher accuracy.
When time intervals are used instead of the peak heights for assessment, it is assessed as follows: the shorter the time intervals of the peaks, the lower the drowsiness level; the longer the time intervals of the peaks, the higher the drowsiness level. Thresholds are also preset in this case.
Thresholds for the peak heights and time intervals are not for everybody, and can be set individually using own data.
If no peaks are detected in palm and fingertip, the driver has possibly fallen asleep already. An object of the present invention is to detect drowsiness before reaching this state. If this state is detected, an alarm using a hazard lamp, voice, a message board or the like is emitted preferentially to the outside of the vehicle, and a stimulus is provided to the driver for alertness.
A trigger (301) for starting a measurement can be programmed in advance and emitted during driving at a specified time interval. Alternatively, a trigger may be emitted by, for example, using a timing of operating a brake or a shift lever, while stopping at an intersection or at a timing of starting a vehicle upon a traffic signal change.
Exemplary data of measured temperature and exemplary processing data are shown in
To assess the drowsiness level, it is possible not only to use differential data but also to detect a difference between temporally successive data so as to assess whether the temperature is on the rise. A second point is measured after a predetermined time of 1 sec., for example, has passed since a first point is measured. A difference between the two measurement values is then calculated. Furthermore, after a predetermined period of time, a third point is measured. Then, a difference between the measurement value of the second point and the measurement value of the third point is calculated. This operation is continued and when the difference remains a positive value continually, the temperature is assessed to be on the rise. In this manner, the drowsiness level can be analyzed with high accuracy.
In the present embodiment, another example of a device for assessing drowsiness level will be described. Here, the apparatus may be used not only in a vehicle but also by a system terminal operator, a PC operator or the like.
Here, description will be omitted for the portions with the same reference signs and the same functions as in the already-described configuration of the in-vehicle drowsiness detection apparatus 100 in
Electrical wiring among a monitor (801), a computer (802), a keyboard (803), and a mouse (804) is omitted in
A palm temperature measurement unit (106) is attached to a portion (808) to be covered with a palm when the mouse is operated with a human hand. There are other techniques such as attaching a surface thermometer to the mouse surface, or attaching a non-contact temperature sensor to the inner structure of the mouse. The drowsiness level can be analyzed with high accuracy by using the above techniques without much costs, and without interrupting normal computer operations.
Procedures for a temperature measurement and a drowsiness level assessment are similar to the procedures in the first embodiment. A monitor (801) can be used as an information presentation unit (107). Stimulus presentation (310) and stimulus/alarm presentation (306) can be implemented by using the monitor (801), voice with a speaker, or the like. Other techniques include providing a vibration function to the mouse (804) or the keyboard (803) and presenting a stimulus to an operator using the vibration. In presenting the above using the monitor (301), a drowsiness detection program or the like is started in advance on a computer terminal (302) or on a system to which the terminal is coupled. In order to prevent an accident caused by, for example, an erroneous operation on the terminal, it is effective to present an alarm, together with information on a problematic terminal, to a system administrator, a labor manager, or the like.
In the present embodiment, an exemplary device for assessing drowsiness level will be described in which a temperature measurement unit (102) is worn by a human and not attached to an apparatus operated by the human, so that drowsiness can be detected substantially wherever the human is. This is effective, for example, for detecting drowsiness of a surveillance staff standing on a ship.
If a portion to be measured is a foot, a technique to use a sock is effective, and if the portion is a hand, a technique to use a glove is effective, but non-limiting. For a sock, effective techniques include attaching a temperature measurement sensor to fiber portions that come in contact with a sole and a fingertip. For a glove, effective techniques include attaching a temperature measurement sensor to fiber portions that come in contact with a palm and a fingertip. Furthermore, there are other effective techniques to incorporate a sensor formed of a material such as carbon nanotubes, which may be fabricated into the fiber. It is also possible to place carbon nanotubes between the temperature measurement sensor and a body surface.
An electrical circuit in a detection system beyond the sensor may be provided outside the glove. Alternatively, a wireless function can be provided in the sensor so that the data can be transmitted wirelessly, but these methods are non-limiting.
Attaching a temperature sensor to footwear such as thong sandals may be effective, other than attaching the sensor to the above-described sock or glove including the glove for drive. In this manner, drowsiness level can be analyzed with high accuracy substantially whenever the human is.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/057340 | 3/15/2013 | WO | 00 |
