![](bg4.png)
Table 1: Obtained results of the proposed algorithm.
# frames # frames
TP TN FP FNopened closed
eyes eyes
13677 222 13062 152 568 130
• True Negatives. The algorithm identifies that
there was no pupil to be detected, e.g. the eye
closed.
• False Positives. The algorithm detects a pupil
where there is none in the image, or the detected
center is too distant (over a choosen threshold)
from the real one.
• False Negatives. The algorithm detects that there
is no pupil even though there is a clearly visible
pupil in the image.
a) b)
Figure 5: Samples frames in which the algorithm fails in
detecting pupil center.
Table 1 shows the incidence of such cases over the
frames of the collected dataset. In 95% of the frames,
the algorithm succeeds in detecting the pupil center or
in detecting a closed eye.
In Fig. 4 it is possible to see three examples in
which the algorithm succeeds in the detection of the
pupil center. The cases are particularly difficult due
to the large rotation of the eye (Fig. 4a) or because
of very long eyebrows (Fig. 4b) or very pronounced
makeup (Fig. 4c). Note also that because of the non
perfect adherence of the mask to the face, dark and
thick regions are present on the image borders: this
causes, in many algorithms, a failure to find the cor-
rect position of the pupil.
In Fig. 5 there are two cases in which the algo-
rithm fails: in the first case, due to the make-up, the
algorithm fails to recognize the closed ey,e while in
the second image, being very noisy, the shape of the
pupil is very distorted.
5 CONCLUSIONS
In this paper a new model-based algorithm for pupil
localization is presented. The algorithm overcomes
some common problems affecting other approaches
by constructing a model that is specific for the ob-
served subject. The experimental results show the ef-
fectiveness of the proposed algorithm.
Future work will be oriented to the use of a more
refined appearance model, incorporating probabilistic
elements, in order to improve the detection accuracy
for very noisy images and for the case in which the
pupil is largely occluded by the eyelid.
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