Relative coordinates oriented symbolic string for spatial relationship retrieval

Issues involving efficient data storage and retrieval have become increasingly important in the design of image database systems. The two dimensional B-string, a kind of symbolic picture representation, has been utilized for both characterizing the spatial knowledge embedded in images and for describing images with either partially or completely overlapping objects, without the need to partition objects. A new more efficient data structure, called the Relative Coordinates Oriented Symbolic String (the RCOS String), is proposed in this paper. Two decision trees are constructed so as to obtain the exact spatial relationship between any two objects. The feasibility of the proposed method is confirmed by performing some empirical analyses.