Eigen Appearance Maps of Dynamic Shapes

We address the problem of building efficient appearance representations of shapes observed from multiple viewpoints and in several movements. Multi-view systems now allow the acquisition of spatio-temporal models of such moving objects. While efficient geometric representations for these models have been widely studied, appearance information, as provided by the observed images, is mainly considered on a per frame basis, and no global strategy yet addresses the case where several temporal sequences of a shape are available. We propose a per subject representation that builds on PCA to identify the underlying manifold structure of the appearance information relative to a shape. The resulting eigen representation encodes shape appearance variabilities due to viewpoint and motion, with Eigen textures, and due to local inaccuracies in the geometric model, with Eigen warps. In addition to providing compact representations, such decompositions also allow for appearance interpolation and appearance completion. We evaluate their performances over different characters and with respect to their ability to reproduce compelling appearances in a compact way.