IEEE Consumer Electronics Magazine - October 2015 - 116

HEAD POsE
This feature determines when there is an
increase in the fatigue level because a
Driver
fatigued driver starts losing muscle tone in
Intrusive
Physiological
the neck; hence, the cranium may begin to
Skin
EEG
Heart Rate Pulse Data Conductivity
have a different position (dropping or
Blinking
moving to the sides) [49]. Another good
aspect of measuring the head pose is that it
Nonintrusive
is possible to be aware of the inattention of
Others
Vision Based
PERCLOS
the driver. For instance, if he or she is
Vehicle
Speed
looking to the side, then inattention is
Driver
present [29]. A common practice is to
Physical
Brakes
Lane
combine the head-position detection with
Departure
Head Pose
other features [28], [29], [40], [55], [74],
Steering
such as eye characteristics, other facial
Wheel
Posture
expressions, or driving reactions.
The company Smart Eye created a
system that uses infrared light and a
camera to measure head pose and eye
feature attributes. As mentioned previously, this company is related to autoFIGURE 5. General DFD systems categories.
motive OEMs and universities [8], [17],
[36], [40], [56]. CMU and its Robotics
Institute have been involved in the facial recognition methods, especially working with active appearance models
The main purpose of the Kalman
(AAMs). AAMs are used for all facial expressions, including
filter is to predict the location
head pose and gaze tracking [28], [55]. At Rensselaer Polytechnic Institute, facial features have been studied. The main
of the face's area.
attributes studied are yawning, head movement, gaze, and
eyelid movement [29]. The Sleep Control Helmet System
(Security Electronic Systems) is generally used in the mining
followed by drowsiness [16]. The BP increases because the
segment, where the users are required to wear a helmet. It
monotonous environment implies a stressful situation.
detects the angle of the head pose [8]. Nap Zapper (Welking)
uses a mercury switch on a device worn around the ear [8].
EEG
An EEG is a physiological measurement; it senses the electrical activity produced by the brain by means of electrodes on
OTHERs
the subject's scalp [49]. Even though the EEG is hard to impleThere are several other ways to define whether the user is
ment in a salable product, some implementations have been
drowsy. For example, yawning is a collateral activity habitumade, mostly at the academic or research level. Research to
ally caused by being drowsy, although a study performed at
develop a noninvasive EEG model is described in [91]. In [60],
the University of California at San Diego has reported that
a brain-computer interface is reported to monitor EEG signals
yawning does not tend to occur in the final moments before
in real time. Sharabaty et al. detail a method to estimate drowsfalling asleep. A couple of implementations have been develiness based on alpha waves in [92].
oped by Rensselaer Polytechnic Institute (Troy, New York)
Some examples of DFD systems that implement EEG
[29], and Shanghai Jiao Tong University (China) [31]. Menare as follows. The drowsiness-detection algorithm by Contal reaction time [8] refers to a tactic where the system
solidated Research, Inc., uses EEG waveforms recorded at
requests an action from the user. This work is reported by
the occipital area, and the output updates every 1.2 s [49].
International Mining Technologies and Muirhead/Remote
The Naval Health Research Center's algorithm uses the
Control Tech [8]. Finally, body movement is measured in the
EEG power spectrum. A baseline or pattern measurement
PASS (Advanced Safety Concepts) [8].
has to be taken to know what would be the alert state of the
specific user. The method reviews the variations in the EEG
CONCLUSION
power spectrum [49]. The Pacific Science and Engineering
This article presents a survey on DFD systems design and
Group combines the use of a vision system, detecting head
technologies. According to the literature reviewed, it is clear
and eye movements, with EEG, but it uses wireless electhere is great interest from private companies, universities,
trodes in an attempt to to diminish the possible rejection of
and governmental organizations to develop DFD systems.
the user [17].
This interest may be related to the increasing number of
DFD System

116 IEEE Consumer Electronics Magazine

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october 2015
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