Ontology-Based Image Retrieval

The binary form of an image does not tell what the image is about. It is possible to retrieve images from a database using pattern matching techniques, but usually textual descriptions attached to the images are used. Semantic web ontology and metadata languages provide a new way to annotating and retrieving images. This paper considers the situation when a user is faced with an image repository whose content is complicated and semantically unknown to some extent. We show how ontologies can then be of help to the user in formulating the information need, the query, and the answers. As a proof of the concept, we have implemented a demonstrational photo exhibition using the promotion image database of the Helsinki University Museum based on semantic web technologies. In this system, images are annotated according to ontologies and the same conceptualization is offered to the user to facilitate focused image retrieval using the right terminology. When generating answers to the queries, the ontology combined with the image data also facilitates, e.g., recommendation of semantically related images to the