Recognition of facial expressions - Knowledge Based Systems ...

Figure 27. Characteristic points area
In the case of detecting the FCP of the left eye, the P1 is considered to be at the first high
intensity pixel from the left side of the characteristic area. In the same way P3 is the right
most pixel having a high intensity. The locations of the upper most and lower most points
of the left eye are computed in the same manner. The same procedure is followed for the
right eye.
In case of the eyebrows, P11 and P13 are the left/right most points in the area to be
analyzed and P9 is the upper most one. For detecting the location of the nose point P17,
the searching area is defined as starting from the coordinates of the pupils to just above
the area of the mouth. The point is found to be the first point with high intensity in the
search from the lowest line to the upper most in the area. The chin point P20 is found in
the same way as P17. For detecting the points in the mouth area the same first pixel
removing procedure is done. The characteristic points are considered to be as the
left/right/up/down most bright points in the mouth area (Figure 27). The result of all the
detection steps is represented in Figure 28.
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