Isosurface Topology Simplification

Many high-resolution surfaces are created through isosurface extraction from volumetric representations, obtained by 3D photography, CT, or MRI. Noise inherent in the acquisition process can lead to geometrical and topological errors. Reducing geometrical errors during reconstruction is well studied. However, isosurfaces often contain many topological errors, in the form of tiny topological handles. These nearly invisible artifacts hinder subsequent operations like mesh simplification, compression, and parameterization. In this paper we present an efficient scheme for removing topological handles in an isosurface. Our scheme makes an axis-aligned sweep through the volume to locate handles, compute their sizes, and selectively remove them. Additionally, the algorithm is designed for out-of-core execution. It finds the handles by incrementally constructing and analyzing a surface Reeb graph. The size of a handle is measured as the shortest surface loop that breaks it. Handles are removed robustly by modifying the volume rather than attempting “mesh surgery.” Finally, the volumetric modifications are spatially localized to preserve geometrical detail. We demonstrate topology simplification on several complex models, and show its benefit for subsequent surface processing. Additional