Towards a fast precision-oriented image retrieval system

Expressive indexing languages are called for to obtain faithful representations of multimedia documents. They become a decisive factor to alleviate the noise problem, which is now often encountered with commercial search engines. In this case, noise consists in a great number of non-relevant answers to user’s queries, which compromises interrogation efficiency. The use of complex formalisms to handle the problem is not straight-forward, as one of their general characteristics is to have high, sometimes unacceptable computational costs. The RELIEF image retrieval system [OP98] is the result of research conducted for several years at the IMAG research institute of the University of Grenoble. It is proposed as a solution to the challenge of using powerful indexing languages to reduce noise and conversely increase precision, while limiting execution times to acceptable values. RELIEF takes benefit from the richness of the conceptual graphs formalism [Sow841 and the speed provided by classical information retrieval (IR) techniques. The system is an operational implementation of a logical IR model applied to the conceptual graphs formalism. A sound algebraic approach is proposed that permits to organize the indexes, which am conceptual graphs, into an inverted file-based structure that is then used for faster retrieval [OP98]. The system is integrated on top of the 02 object-oriented DBMS, which provides a complete programming environment, including the fourth generation language OsC, the OQL query language that conforms to the ODMG standard, and the OzLook graphical interface tool. The architecture of our system is shown in figure 1. It supports image handling, by an image manager that makes use of basic 0s classes. The ROGER platform [Oun98] handles conceptual graphs; it is programmed in OsC and an 02Look interface allows for off-line insertion, change, consistency tests and visualization of the indexes. Retrieval can be performed from a Web browser, through our interrogation interface, which uses the OsWeb tool to access the database. To achieve portability and to manage the presentation, an additional JAVA-based layer is provided. The availability of recent advances in the object-oriented database domain and the support of database connections via Web browsers are the main reasons for the choice of 0s OG DBMS. RELIEF is proposed as a solution to the integration of object oriented modeling and Web technologies in the IR domain, based on indexing and interrogation functionalities. l Indexing facilities Image indexing is performed with a computer-assisted pmcess, according to a particular image indexing model [Mec95]. A basic part of the indexing consists in the introduction and