14 Defining Views in an Image Database System

A view mechanism can help handle the complex semantics in emerging application areas such as image databases. This paper presents the view mechanism we de ned for the DISIMA image database system. Since DISIMA is being developed on top of an object-oriented database system, we rst propose a powerful object-oriented view mechanism based on the separation between types (interface functions) and classes that manage objects of the same type. The image view mechanism uses our object-oriented view mechanism to allow us to give di erent semantics to the same image. The solution is based on the distinction between physical salient objects which are interesting objects in an image and logical salient objects which are the meanings of these objects.