This paper proposes a technique for indexing, clustering and retrieving images based on their edge features. In this technique,
images are decomposed into several frequency bands using the Haar wavelet transform. From the one-level decomposition sub-bands
an edge image is formed. Next, the higher order auto-correlation function is applied on the edge image to extract the edge
features. These higher order autocorrelation features are normalized to generate a compact feature vector, which is invariant
to shift, image size and gray level. Then, these feature vectors are clustered by a self-organizing map (SOM) based on their
edge feature similarity. The performed experiments show the high precision of this technique in clustering and retrieving
images in a large image database environment.