Recognition of facial expressions - Knowledge Based Systems ...

updating the probabilities, the system is able to provide the user with the emotional load
for every expression.
Eye Detection Module
In order to detect the location of the eyes in the current frame, the specialized module
passes the input image through a set of simple processing tasks. The initial image looks
like that in Figure 21.
Figure 21. Initial IR image
The eye detector makes use of the property that the reflection of the infra red light on the
eye is visible as a bright small round surrounded by a dark area. The routine is supposed
to search for pixels that have that property. Finally the eye locations are chosen as the
first two in a recovered candidate list.
First a Sobel-based edge detector is applied for detecting the contours that exists in the
image. The reason of applying an edge detector is that the searched items contain a clear
transition area in the pixels’ color. The result is as in Figure 22.
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