Distance measures like the Euclidean distance are used to measure similarit
y between images in content-based image retrieval. Such geometric measures
implicitly assign more weighting to features with large ranges than those w
ith small ranges. This paper discusses the effects of five feature normaliz
ation methods on retrieval performance. We also describe two likelihood rat
io-based similarity measures that perform significantly better than the com
monly used geometric approaches like the L-p metrics. (C) 2001 Elsevier Sci
ence B.V. All rights reserved.