boundary_distance

Wichtig sind:

- inner und outer boundary ansatz: 
include/vigra/multi_distance.hxx                              
- vektor distanz transformation: 
include/vigra/vectorial_distance.hxx                        
- vektor distanz transformation mit komponentenweiser korrektur: 
include/vigra/vectorial_boundary_distance.hxx        
- test von boundary vdt: 
test/multidistance/test.cxx