Removal and contraction operations to define combinatorial pyramids: application to the design of a spatial modeler

Removal and contraction are basic operations for several methods conceived in order to handle irregular image pyramids, for multi-level image analysis for instance. We give the definitions of removal and contraction operations in the generalized maps framework. We propose a first experimentation of irregular pyramid as a basis for a discrete geometrical modeler that can handle both discrete and continuous representations of geometrical objects. This modeler is based on a pyramidal kernel with four coexisting level between the discrete and the Euclidean representations. We describe how this pyramid can be constructed and updated.