Retrieval of multimedia documents by imprecise query specification

The retrieval process in multimedia document systems is inherently different from the retrieval process in traditional (record oriented) database systems. While the latter can be considered an exact process (records either satisfy the query or not), the former is not an exact process and the system must take into account the uncertainty factor (i.e. the answer is not only "true" or "false" but is often in between them). Uncertainty is mainly introduced in evaluating how images and text components in documents are relevant to user's queries. Moreover, it may be useful to give the user some flexibility in specifying the query on multimedia documents (i.e. the "importance" of different parts of the query). The possibility to specify imprecise queries in a system can significantly increase the effectiveness and the precision in the retrieval process on multimedia documents. This approach is being tested extending the MULTOS system, a prototype system for the storage and retrieval of multimedia documents.