An invariant handwritten Chinese character recognition system is propo
sed. Characters can be in arbitrary location, scale and orientation. F
ive invariant features are employed in this study. The first four feat
ures are used for preclassification to reduce matching time. The last
feature, ring data, constructs ring-data vectors to characterize chara
cter samples and constructs weighted ring-data matrices to characteriz
e characters to further reduce matching time. Fuzzy membership functio
ns are defined based on these two characteristics to match characters.
A character set is constructed from 200 handwritten Chinese character
s and comprising several different samples of each character in arbitr
ary orientations. The performance of the proposed invariant features a
nd fuzzy matching is verified through extensive experiments with the c
haracter set: (i) the performance of the proposed fuzzy matching is su
perior to that of two traditional statistical classifiers; (ii) the pe
rformance of the fuzzy ring-data vector is clearly superior to that of
the fuzzy ring-data matrix, but the latter needed less matching time;
(iii) the preclassification reduces the fuzzy matching time and impro
ves the recognition rate; and (iv) the performance of the proposed inv
ariant features is clearly superior to that of moment invariants.