Contour Lines
Lines are either:
- limbs: surface of object tangential to camera angle (<<- or ->>)
- edges: surface normal discontinuity
- concave (-)
- convex (+)
- occluding (<-- or -->)
Using the Huffman-Clowes label set, trihedral objects have
vertices composed of the intersection of 3 planes. The
Waltz algorithm for labeling line drawings can then be used.
This models edge labeling as a constraint satisfaction problem (CSP)
in which each line gets one label.
