Waltz Filtering Process
The constraint propagation rapidly reduces the size of
the search space of possible interpretations: each time a node
label is deleted, the branching factor of the search at that
node is reduced by one.
- Associate with each vertex a set of all possible labels
for that vertex type.
- Compare the label sets along lines: a label for a line must
be consistent at both ends. If a vertex label involves a line
label that cannot be matched at the other end, that vertex label
can be deleted.
- As vertex labels are deleted, see if other vertices adjacent
along some line are further constrained.
- Continue until no further deletions are possible.
- Search in the reduced label set for globally consistent