An efficient prototype merging strategy for the condensed 1-NN rule through class-conditional hierarchical clustering

A generalized prototype-based classi2cation scheme founded on hierarchical clustering is proposed. The basic idea is to obtain a condensed 1-NN classi2cation rule by merging the two same-class nearest clusters, provided that the set of cluster representatives correctly classi2es all the original points. Apart from the quality of the obtained sets and its 5exibility which comes from the fact that di7erent intercluster measures and criteria can be used, the proposed scheme includes a very e cient four-stage procedure which conveniently exploits geometric cluster properties to decide about each possible merge. Empirical results demonstrate the merits of the proposed algorithm taking into account the size of the condensed sets of prototypes, the accuracy of the corresponding condensed 1-NN classi2cation rule and the computing time. ? 2002 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.