Logical features are abstract representations of images at various levels of detail. Some logical features such as spa-
The image retrieval based on spatial content is an attracting task in many image database applications. The 2D strings protial-location and spatial-relation [18] may be synthesized vide a natural way of constructing spatial indexing for images from primitive features, whereas others can only be oband support effective picture query. Nevertheless, the 2D string tained through considerable human involvement. Spatial is deficient in describing the spatial knowledge of nonzero sized constraint is a significant logical feature and is our focus objects with overlapping. In this paper, we use an ordered in this article.
labeled tree, a 2D C-tree, to be the spatial representation for
The intelligent image database system (IIDS) [4] proimages and propose the tree-matching algorithm for similarity vides high-level object-oriented search and supports spatial retrieval. The distance between 2D C-trees is used to measure query. The spatial reasoning is based on a data to structure the similarity of images. The proposed tree comparison algocalled 2D string [3] which preserves the objects' spatial rithm is also modified to compute the partial tree distance knowledge embedded in images. Each symbolic picture for subpicture query. Experimental results for verifying the can be represented by a 2D string and a picture query can effectiveness of similarity retrieval by 2D C-trees matching are also be specified by a 2D string. The problem of image presented. © 1998 Academic Press retrieval then becomes a problem of 2D string subsequence matching [15]. Lee and Hsu [13] proposed 2D C-string