Artificial Intelligence and Soft Computing: Behavioral ... - Arteimi.info

matches (a) and (b). Similarly, we labeled other junctions. Now, in many
junctions we have more than one possible label. We can overcome it by
considering the ‘constraints of neighboring junctions’ [8], so that the type of
each junction is unique for a realistic object. Careful observation yields that
since A and B are neighboring junctions, trying to connect (a) with (c) and (b)
with (c) shows that (a)-(c) connection is feasible. The constraints of
neighborhood junctions are applied to each label to reduce it to a single type
per junction. The result of the type reduction is presented below.
Table 19.2: Junction type reduction.
Junctions possible name of label
A (a)
C (d)
E (g)
G (k)
The algorithm for junction labeling, also called the waltz algorithm [9], is
presented below.
Procedure junction-labeling (edges, labels)
Begin
1. Label boundary by clockwise encirclement;
2. Label interior edges by ‘+’ or ‘-’ as convenient;
3. Label junction types from the possible match with fig. 19.13. You may
allow rotation of types and the types need not be uniqu;
4. Reduce the types of each junction to a single one by considering the
types of the neighboring junctions;
5. Repeat step 4 until each junction of the object has a single type.
End.
19.7 Conclusions
The chapter introduced three basic types of CSP dealing with algebraic,
logical and geometric constraints. The concept of constraint simplification and
equivalence is discussed and constraint propagation in networks has been
illustrated. The principles of constraint logic programming are also presented
with examples. An algorithm for constraint satisfiability testing is discussed.
The concepts of recognizing trihedral objects from their junction labeling
have also been covered briefly.