Face Detection and Modeling for Recognition - Biometrics Research ...

average C 2 r
to the average C r /C b . Figure 3.11 shows the major steps in computing
the mouth map of the subject in Fig. 3.9. Note that after the mouth map is dilated,
masked, and normalized, it is dramatically brighter near the mouth areas than at
other facial areas.
Figure 3.11.
Construction of the mouth map.
3.3.3 Eye and Mouth Candidates
We form an eye-mouth triangle for all possible combinations of two eye candidates
and one mouth candidate within a face candidate. We then verify each eye-mouth
triangle by checking (i) luma variations and average gradient orientations of eye and
mouth blobs; (ii) geometry and orientation constraints of the triangle; and (iii) the
presence of a face boundary around the triangle.
A weight is computed for each
verified eye-mouth triangle.
The triangle with the highest weight that exceeds a
threshold is selected. We discuss the detection of face boundary in Section 3.3.4, and
the selection of the weight and the threshold in Section 3.3.5.
Note that the eye and mouth maps are computed within the entire areas of the
face candidate, which is bounded by a rectangle. The search for the eyes and the
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