In this paper a new character description method, based on the combination
of structural and statistical approaches, is presented. Characters are prel
iminarily decomposed in terms of structural primitives (circular arcs) and
successively described in terms of statistical features (geometric moments)
. The obtained description is much more stable and yields significant impro
vements in classification performance: its effectiveness has been demonstra
ted by comparing the recognition results obtained by applying the geometric
moments directly on the character bit maps and, as proposed, on the charac
ter decomposition in circular arcs. Absolute and relative performance is si
gnificant especially for particularly critical cases. Novel recurrent formu
lae for evaluating in a closed form the moments of objects represented in t
erms of circular arcs are also introduced; experimental results reveal a si
gnificant reduction of the time needed for evaluating the moments. (C) 1999
Elsevier Science B.V. All rights reserved.