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BIometrIC systems
similarity is calculated by the cosine of the angle between their vec-
tors, on the Euclidean distance. In other words, if the cosine is zero,
then the images are totally dissimilar.
2.5.6 Effect of the Eyebrows and Upper and Lower Eyelids
e eyelids and eyebrows hide a part of the iris. is affects the per-
formance of the authentication process.
To overcome these problems, Daugman (2004) and Wildes (1997)
modeled the upper and lower eyelids with parabolic arcs. Miyazawa
et al. (2005) and Daouk et al. (2002) have used only the lower part of
the iris for authentication. is method has proven an effectiveness of
100% at the level of verification (Daouk et al. 2002). Tian et al. (2006)
adopted the linear Hough transform. ey used ...