Volume - based three - dimensional metamorphosis using region correspondence

The metamorphosis (commonly known as morphing) of one image into another is a well studied subject that has frequently been used to create impressive visual effects. There has been significant work recently in three-dimensional (3-D) metamorphosis, where a surface is transformed into another surface. One approach is to construct discrete volume representations of the surfaces and interpolate between them to create intermediate volumes. With the advance of volume graphics, these volumes can be directly rendered in real time, or alternatively one of the many isosurface extraction techniques can be used to construct a polygonal mesh from each volume for rendering using standard hardware. This technique is independent of the surface topology, which enables morphing between surfaces of completely different shape — however it can also lead to unrealistic intermediate surfaces which have different topology from the originals. We present a method for correcting this problem by automatically calculating region correspondence derived from a representation of each surface as a set of spheres. We also show how this can be combined with a simple method for manually defining correspondence. In combination, this proves to be a fast and flexible method for morphing surfaces, as demonstrated on a wide range of examples.