In this paper, several classification methods are presented and a fusion structure is included to improve the final classification performance. The definition of "layer" and the method to create it are then introduced. Based on "layer", a multiple level change detection algorithm is proposed, which gives the details of the changes in each region and is demonstrated to be an easy, effective and reliable method. Experimental results are provided using RADARSAT images, which have been registered with the automated registration algorithm of A.U.G. Signals that is currently available under the distributed processing system www.signalfusion.com.