A generic framework for efficient 2-d and 3-d facial expression analogy

Facial expression analogy provides computer animation professionals with a tool to map expressions of an arbitrary source face onto an arbitrary target face. In the recent past, several algorithms have been presented in the literature that aim at putting the expression analogy paradigm into practice. Some of these methods exclusively handle expression mapping between 3-D face models, while others enable the transfer of expressions between images of faces only. None of them, however, represents a more general framework that can be applied to either of these two face representations. In this paper, we describe a novel generic method for analogy-based facial animation that employs the same efficient framework to transfer facial expressions between arbitrary 3-D face models, as well as between images of performer's faces. We propose a novel geometry encoding for triangle meshes, vertex-tent-coordinates, that enables us to formulate expression transfer in the 2-D and the 3-D case as a solution to a simple system of linear equations. Our experiments show that our method outperforms many previous analogy-based animation approaches in terms of achieved animation quality, computation time and generality.