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Recognition of facial expressions - Knowledge Based Systems ...

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Figure 28. FCP detection<br />

The efficiency in detection <strong>of</strong> FCPs is strictly related to the efficiency <strong>of</strong> pupil position<br />

recovering. In order to make the pupil detection routine more reliable, an enhancement<br />

has been done based on Kalman Filter. The mechanism is supposed to do a tracking <strong>of</strong><br />

pupils in the time dimension by involving a permanent estimation <strong>of</strong> the parameters (as<br />

position, velocity, acceleration, etc.). The situations when the eyes are closed are now<br />

correctly processed by the visual feature detection module. The output <strong>of</strong> the system can<br />

be a simple graph showing the variation <strong>of</strong> the emotional load in time or on the form <strong>of</strong> a<br />

graphical response. The result <strong>of</strong> the processing may also include an emotional load,<br />

similar to that <strong>of</strong> the input signal, or different, according to a secondary reasoning<br />

mechanism.<br />

Face representational model<br />

The <strong>facial</strong> expression recognition system handles the input video stream and performs<br />

analysis on the existent frontal face. In addition to the set <strong>of</strong> degree values related to the<br />

detected <strong>expressions</strong>, the system can also output a graphical face model.<br />

The result may be seen as a feedback <strong>of</strong> the system to the given <strong>facial</strong> expression <strong>of</strong> the<br />

person whose face is analyzed and it may be different <strong>of</strong> that. One direct application <strong>of</strong><br />

the chosen architecture may be in a further design <strong>of</strong> systems that perceive and interact<br />

with humans by using natural communication channels. In the current approach the result<br />

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