Mouth Segmentation Using Active Contours
AUTHORS:
P. Juran, P. Krsek, L.J.M. Rothkrantz,
V. Hlavac
KEYWORDS:
ABSTRACT:
This report describes our approach to localisation
of the exact position of lips and teeth on a picture of mouth. Acquired
information about mouth position will be used as input data for emotion
recognition system. Basic demand is a good functionality on pictures of
face without special make-up. Our algorithm consists of four steps:
-
Preprocessing - image filtering
-
Finding mouth-through line - valley detection and area growing
-
Locating lips contour - active contours (snakes)
-
Searching for teeth - active contours (snakes)
In the first part of our report we are interested in
image preprocessing. Colour information is used to obtain a picture with
better contrast and the image is further processed by filtering. Then we
locate the mouth-through line using two stage algorithm of valley detection
and area growing. The line is used for definition of the starting conditions
of the next step, the snakes. In the next part, we pay attention especially
to definition of the energy of the active contour, terminating condition
and the requirements of correct development. We experimented with several
image definitions and their availability will be also discussed. In the
final part we will describe results and conditions for realised experiments.
This page was created on January 19, 1998 by Anna
Wojdel