We present a supervised classification model based on a variational approac
h. This model is devoted to find an optimal partition composed of homogeneo
us classes with regular interfaces. The originality of the proposed approac
h concerns the definition of a partition by the use of level sets. Each set
of regions and boundaries associated to a class is defined by a unique lev
el set function. We use as many level sets as different classes and all the
se level sets are moving together thanks to forces which interact in order
to get an optimal partition. We show how these forces can be defined throug
h the minimization of a unique fonctional. The coupled Partial Differential
Equations (PDE) related to the minimization of the functional are consider
ed through a dynamical scheme. Given an initial interface set (zero level s
et), the different terms of the PDE's are governing the motion of interface
s such that, at convergence, we get an optimal partition as defined above.
Each interface is guided by internal forces (regularity of the interface),
and external ones (data term, no vacuum, no regions overlapping). Several e
xperiments were conducted on both synthetic and real images.