Lab meeitng 1 Nov., 2006 (Vincent): Fitting a Single Active Appearance Model Simultaneously to Multiple Images

In this talk, I will present the following 2 papers.

Title :
Fitting a Single Active Appearance Model Simultaneously to Multiple Images

Author :
Changbo Hu, Jing Xiao, Iain Matthews, Simon Baker, Jeff Cohn and Takeo Kanade
The Robotics Institute,CMU

Origin :
BMVC 2004

Abstract :
Active Appearance Models (AAMs) are a well studied 2D deformable model. One recently proposed extension of AAMs to multiple images is the Coupled-View AAM. Coupled-View AAMs model the 2D shape and appearance of a face in two or more views simultaneously. The major limitation of Coupled-View AAMs, however, is that they are specific to a particular set of cameras, both in geometry and the photometric responses. In this paper, we describe how a single AAM can be fit to multiple images, captured simultaneously by cameras with arbitrary geometry and response functions. Our algorithm retains the major benefits of Coupled-View AAMs:~the integration of information from multiple images into a single model, and improved fitting robustness.



Title :
Real-Time Combined 2D+3D Active Appearance Models

Author :
Jing Xiao, Simon Baker, Iain Matthews, and Takeo Kanade
The Robotics Institute,CMU

Origin :
CVPR 2004

Abstract :
Active Appearance Models (AAMs) are generative models commonly used to model faces. Another closely related type of face models are 3D Morphable Models (3DMMs). Although AAMs are 2D, they can still be used to model 3D phenomena such as faces moving across pose. We first study the representational power of AAMs and show that they can model anything a 3DMM can, but possibly require more shape parameters. We quantify the number of additional parameters required and show that 2D AAMs can generate model instances that are not possible with the equivalent 3DMM. We proceed to describe how a non-rigid structure-from-motion algorithm can be used to construct the corresponding 3D shape modes of a 2D AAM. We then show how the 3D modes can be used to constrain the AAM so that it can only generate model instances that can also be generated with the 3D modes. Finally, we propose a real-time algorithm for fitting the AAM while enforcing the constraints, creating what we call a "Combined 2D+3D AAM."