The main goal of this project is to develop an image thesaurus to facilitate content based search of large digital image/video libraries. As computers and communications technology advance, limitations of current information processing tools are becoming more apparent, and is particularly visible in the context of media rich data such as satellite and medical imagery databases. The image or visual thesaurus provides a conceptual framework for similarity search and indexing of such multimedia data. At the time of data ingest, image features of interest, such as color, texture, spatial location and shape, are computed and clustered to give a feature code book. Application specific information and user requirements are used to make this code book construction adaptive. The mapping to code words is hierarchical and groupings of several basic features can be used to represent high level structured visual concepts. Key components in this thesaurus construction include new spatio-temporal segmentation algorithms, and dimensionality reduction and learning algorithms for efficient search and indexing in the feature space. Potential applications of this thesaurus include geographic information systems, medical imagery, searching on the Internet using image content, and in new image/video coding standards such as MPEG-7. A prototype retrieval system incorporating an image thesaurus will be developed and its effectiveness will be demonstrated on searching airphoto databases and stock photo galleries.
