An overview of concepts in fusion of Earth data

A definition of the data fusion is proposed, which allows to set up a conceptual approach to the fusion of Earth observation data by putting an emphasis on the framework and on the fundamentals in remote sensing underlying data fusion. Further definitions are given which describe the information intervening in any problem of data fusion. Fusion may be performed at different levels: at measurements level, at attribute level, and at rule or decision level. Several problems are to be solved prior to any process of fusion. They deal with either the selection of the representation space and the level of fusion, or with the processing to be applied onto the data. A formalism is discussed which sketches a fusion process. Several examples of fusion processes are given using this formalism.