System for efficient content-based retrieval of images

Abstract

A system creates and uses a visual image index for visual image retrieval. The visual image index uses multi-level filtering to reduce the processing and storage needed to identify visual images in a table that have similar characteristics to those of a query image. Information about a visual image is stored in an image signature that contains data about basic visual primitives of the image (e.g., global color, local color, texture and structure). The signature is stored in a database table along with the image itself (or a link to the image). Visual image retrieval is performed by searching for signatures in the database that are similar to the signature of the query image. The multi-level filtering reduces the number of candidate images, before a full comparison is done on the filtered-set of candidate image signatures. The first sub-filter performs a range-based query on a table of image attributes culled from the image signature, each attribute in this table is indexed. The results of the range-based sub-filter are processed by a functional predicate sub-filter which determines a distance measure of each resultant image from the query image. The results of the functional predicate sub-filter are compared, using full signature comparison logic, to the query image signature to determine whether the query image is similar to a visual image in the table.