糖心TV

For the most part, shape modelling has focused on modelling families
of regions consisting of deviations around a given reference shape
with a simple topology. There are applications, however, where the
family of regions involved does not show such constrained behaviour.
Cases where the number of objects is unknown a priori, or where the
topology of the region may be otherwise complex (for example network
shapes), require new techniques. 'Higher-order active contours'
(HOACs) represent one approach to modelling such families of regions.
By introducing explicit long-range interactions between region
boundary points, HOACs can model families of regions sharing geometric
properties without overly constraining region topology. Representing
regions by their boundaries is often inconvenient, however, both
analytically and numerically, especially for complex topologies. An
alternative is the approach known as 'phase field' modelling. The
phase field representation and modelling framework offers a number of
advantages, both for the simplest region models and for HOACs. By way
of illustration, the use of HOAC and HOAC phase field models to
estimate the regions corresponding to road networks and tree crowns in
satellite and aerial images will be described