Content-based image retrieval - A survey

Current technology allows the acquisition, transmission, storing, and manipulation of large collections of images. Images are retrieved basing on similarity of features where features of the query specification are compared with features from the image database to determine which images match similarly with given features. Feature extraction is a crucial part for any of such retrieval systems. So far, the only way of searching these collections was based on keyword indexing, or simply by browsing. However nowadays digital images databases open the way to content-based efficient searching. In this paper we survey some technical aspects of current content-based image retrieval systems.