A Temporal Meta Database System for 3D Objects

Nowadays, semantic information accompanying 3D graphical data, which is called metadata, has been realized to be essential for several purposes such that available 3D graphical data can be indexed and retrieved by means of its metadata and then other applications can make use of the 3D graphical data efficiently. Even though a number of works have focused on this topic so far, no temporal aspect of 3D graphical data has been taken into account. Especially no complete automatic metadata extraction process has been proposed. A manual process is possible with a small amount of 3D graphical data while impossible with a larger amount. Therefore, the manual process gets heavy and the cost in time and effort is so much required. In such a context, we introduce for 3D graphical data a temporal meta database system where an automatic metadata extraction method takes into consideration the temporal aspect of 3D graphical data. 3D graphical data is arranged in a scene formatted in the standard language VRML. Semantic information of the scene, i.e. metadata, will be automatically achieved. The structure of scene metadata is handled by using the temporal NIAM object oriented conceptual schema model at the abstraction level so that the semantic scene information can get more understandable to users, graphics designers, and application programmers as well. As a result, scene metadata is able to be easily stored and queried by means of some standardized database language such as SQL or OQL. With the aid of the extracted scene metadata, the respective 3D scenes are now exactly and conveniently accessed by other applications such as a virtual guide in transportation, architecture, tourism, etc.