GEOMETRICAL, TOPOLOGICAL, AND HIERARCHICAL STRUCTURING OF OVERLAPPING2-D DISCRETE OBJECTS

A model of scenes composed of 2-D discrete objects is presented. A gen eralization of the 2 1/2 - D positioning features usually implemented in 2 1/2 - D environment is given, treating object superimposition. Th e positioning representation sits on an explicit topological and geome trical encoding of object boundaries. This approach allows structured manipulations of objects (intersection, combination,...) and efficient redisplay of scene, such that every modified pixel is drawn exactly o nce. Moreover, this model is consistent from a geometrical and topolog ical point of view and allows the construction of a scene from a digit al image. Many applications can be considered: graphics editors, paint boxes, image processing environments, etc. (C) 1997 Elsevier Science L td. All rights reserved.