A MULTIMEDIA QUERY SPECIFICATIONLANGUAGENael

Typically, multimedia applications involve thousands of hours of video, images, audio , text and graphics that need to be stored, retrieved and manipulated in a large multimedia database. There is therefore an important need for novel techniques and systems which provide an eecient retrieval facility of the voluminous information stored in the multimedia database. Such facility will consist of a query language, a data structure, and a content searching algorithm. In this chapter we propose a multimedia query speciication language that can be used to describe the multimedia content portion to be retrieved from the database. Such a content portion is termed a multimedia segment which may contain information on the media as well as the temporal and spatial relationships that may exist between these media 1 MOTIVATION There is a growing number of multimedia applications that require a retrieval facility ooering detailed views of multimedia document contents. Such a facility should allow query-based retrieval activities directed towards extracting individual multimedia portions of documents. This leads to multimedia segment retrieval (in short multisegment retrieval) whereby attempts are made to retrieve individual excerpts of multimedia documents. Similar to text passage retrieval 1], multisegment retrieval rests on the exhaustive search of document content for the purpose of retrieving all multisegments that fullll the specii-cations of a query. 1 2 Chapter 1 There is a potential for multisegment retrieval facilities in applications such as multimedia document browsing and retrieval. Browsing multimedia documents through visual representations, such as Hypermedia, involves traversing numerous levels of tree-like structures. This task may nd the user lost, especially when a detailed view of content is required. Therefore, it is more convenient in this case to use a multisegment retrieval facility that allows users to access document portions by formulating content queries. Multimedia information retrieval has not received as much attention as single media information retrieval. Although query mechanisms have been proposed for speciic types of documents (e.g., documents having only text and image content 2]), no attempt has been made to address a wide range of multimedia documents. In this chapter, we propose a multimedia content speciication that can describe diierent multimedia documents. This speciication permits retrieval of potentially relevant multisegments from a multimedia database. The user may, for instance, retrieve a multisegment(s) in which video shots of the 1995 G7 meeting are displayed, the voice of an anchorperson discussing the role of Canada is played out, and …