In this paper we consider the task of matching patterns, as occur in hand-d
rawn symbols and schematic diagrams, by their parts and relationships. Of p
articular interest for computer vision is the integration of two approaches
to the recognition by parts problem-graph matching and syntactic rule-base
d approaches. A new procedure is developed, named CLARET, which matches par
ts and relationships by tightly coupling the processes of matching and rule
generation at run time. We have developed an interactive system for interp
reting hand-drawn symbols and schematic drawings. The system operates invar
iant to rotation, scale, and position and projects images onto a drawing ca
nvas. The procedure is analyzed for its ability to accommodate new symbols
and answer orientation queries, and it is compared empirically with machine
learning techniques. (C) 1999 Academic Press.