The Acoi Algebra: a Query Algebra for Image Retrieval Systems

Content-based image retrieval systems rely on a query-by-example technique often using a limited set of global image features. This leads to a rather coarse-grain approach to locate images. The next step is to concentrate on queries over spatial relations amongst objects within the images. This calls for a small collection of image retrieval primitives to form the basis of an image retrieval system. The Acoi algebra is such an extensible framework built on the relational algebra. New primitives can be added readily, including user-defined metric functions for searching. We illustrate the expressive power of the query scheme using a concise functional benchmark for querying image databases.