This module reduces the total variation
\index{total variation}
\index{Fast Level Set Transform} 
of an image by modifying the local
contrast of shapes in a bilinear interpolated image 
\index{interpolation!bilinear}
(see \texttt{flst\_bilinear}). 
More precisely, it is a scale-space depending on a
scale parameter $t$. The contrast of a shape relatively to its background is
reduced at a speed proportional to the global curvature of its boundary,
defined as the ratio $C=\frac{L}{A}$, $L$ being the length and $A$ the
area. The contrast of a leaf in the tree is reduced of $t C$. If this amount
is superior to the original contrast $c$, the leaf is removed and we try to
reduce the contrast of its parent according to the scale $t-\frac{c}{C}$,
provided it has no other child. If it has other children, we apply the same
operation to each corresponding branch. If each one is removed in the process,
the scale parameter we apply to the shape is $t$ minus the amount of scale
used by each branch.

The parameter \texttt{quantization} represents a subsampling of the tree of
bilinear level lines such that the contrast between a shape and its parent is
at most \texttt{quantization}.

The parameter \texttt{precision} is linked to the discretization of the level
lines (see \texttt{flstb\_boundary}).

This filter is presented by F. Dibos and G. Koepfler.
