Modeling and querying video databases

Indexing video data is essential for providing content based access. This paper develops a data model and a rule-based query language for video content based indexing and retrieval. The data model is based on the notion of generalized strata, which can be seen as a set of intervals. Each interval can be analyzed to extract symbolic descriptions of interest that can be put into a database. This database can then be searched to find information of interest. Two types of information are considered: the entities (objects) in the domain of a video sequence; and video frames, called generalized strata, which contain these entities. To represent this information, our data model allows facts as well as objects and constraints. We present a declarative, rule-based, constraint query language that can be used to infer relationships about information represented in the model. In the video applications we are interested in, we wish to construct new generalized strata from old ones. To do this, our language has an interpreted function term (i.e., constructive term) to concatenate generalized strata. The language has a clear declarative and operational semantics