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We present a new method to determine contraction kernels for the construction of graph pyramids. The new method works with undirected graphs and yields a reduction factor of at least 2.0. This means that with our method the number of vertices in the subgraph induced by any set of contractible edges is reduced to half or less by a single parallel(More)
We present two new methods to determine contraction kernels for the construction of graph pyramids. The first method is restricted to undirected graphs and yields a reduction factor of at least £ ¥ ¤ § ¦. This means that with our method the number of vertices in the subgraph induced by any set of contractible edges is reduced to half or less by a single(More)
A hierarchy of increasingly coarse versions of a network allows one to represent the network on multiple scales at the same time. Often, the elementary operation for generating a hierarchy on a network is merging adjacent vertices, an operation that can be realized through contracting the edge between the two vertices. Such a hierarchy is defined by the(More)
When matching regions from " similar " images, one typically has the problem of missing counterparts due to local or even global variations of segmentation fineness. Matching segmentation hierarchies, however, not only increases the chances of finding counterparts, but also allows us to exploit the manifold constraints coming from the topological relations(More)
Human image understanding copes with image intensity transformations, as long as they are monotonic, i.e. the local ordering of the intensities is nowhere disturbed. Conversely , changes in image structure entail intensity transformations, which are not mono-tonic. In this paper, we study a class of dual image graph contractions, such that each member of(More)