  Unobtrusive every day health monitoring can be of important use for the
elderly population. In particular, pupil size may be a valuable source of
information, since, apart from pathological cases, it can reveal the emotional
state, the fatigue and the ageing. To allow for unobtrusive monitoring to gain
acceptance, one should seek for efficient methods of monitoring using com- mon
low-cost hardware. This paper describes a method for monitoring pupil sizes
using a common web camera in real time. Our method works by first detecting the
face and the eyes area. Subsequently, optimal iris and sclera location and
radius, modelled as ellipses, are found using efficient filtering. Finally, the
pupil center and radius is estimated by optimal filtering within the area of
the iris. Experimental result show both the efficiency and the effectiveness of
our approach.
