Quicklook2: An Integrated Multimedia System

The need to retrieve visual information from large image collections is shared by many application domains. This paper describes the main features of the multimedia information retrieval engine of Quicklook2. Quicklook2allows the user to query image and multimedia databases with the aid of sample images, or an impromptu sketch and/or textual descriptions, and progressively refine the system's response by indicating the relevance, or non-relevance of the retrieved items. The major innovation of the system is its relevance feedback mechanism that performs a statistical analysis of both the image and textual feature distributions of the retrieved items the user has judged relevant, or not relevant to identify what features the user has taken into account (and to what extent) in formulating this judgement, and then weigh their influence in the overall evaluation of similarity, as well as in the formulation of a new, single query that better expresses the user's multimedia information needs. Another important contribution is the design and integration with the relevance feedback mechanism of an indexing scheme based on triangle inequality to improve retrieval efficiency. The performance of the system is illustrated with examples from various application domains and for different types of queries (target search as well as similarity search). © 2001 Academic Press.