Jean Ponce
Ecole Normale Superieure, Paris,
France
Abstract
This paper proposes a novel
approach to motion capture from multiple, synchronized video streams,
specifically aimed at recording dense and accurate models of the
structure and motion of highly deformable surfaces such as skin, that
stretches, shrinks, and shears in the midst of normal facial
expressions. Solving this problem is a key step toward effective
performance capture for the entertainment industry, but progress so far
has been hampered by the lack of appropriate local motion and smoothness
models. The main technical contribution of this paper is a novel
approach to regularization adapted to nonrigid tangential deformations.
Concretely, we estimate the nonrigid deformation parameters at each
vertex of a surface mesh, smooth them over a local neighborhood for
robustness, and use them to regularize the tangential motion estimation.
To demonstrate the power of the proposed approach, we have integrated it
into our previous work for markerless motion capture [9], and compared
the performances of the original and new algorithms on three extremely
challenging face datasets that include highly nonrigid skin
deformations, wrinkles, and quickly changing expressions. Additional
experiments with a dataset featuring fast-moving cloth with complex and
evolving fold structures demonstrate that the adaptability of the
proposed regularization scheme to nonrigid tangential motion does not
hamper its robustness, since it successfully recovers the shape and
motion of the cloth without overfitting it despite the absence of
stretch or shear in this case.
Acknowledgments This work was supported in
part by the National Science Foundation grant IIS-0535152 and
IIS-0811878, the INRIA associated team Thetys, the Agence Nationale de
la Recherch under grants Hfibmr and Triangles, the Office of
Naval Research, the University of Washington Animation Research Labs,
and Microsoft. We thank R. White, K. Crane and D.A. Forsyth for the
pants dataset. We also thank Hiromi Ono, Doug Epps and ImageMovers
Digital for the face datasets.