Simultaneous pose and non-rigid shape with particle dynamics

In this paper, we propose a sequential solution to simultaneously estimate camera pose and non-rigid 3D shape from a monocular video. In contrast to most existing approaches that rely on global representations of the shape, we model the object at a local level, as an ensemble of particles, each ruled by the linear equation of the Newton's second law of motion. This dynamic model is incorporated into a bundle adjustment framework, in combination with simple regularization components that ensure temporal and spatial consistency of the estimated shape and camera poses. The resulting approach is both efficient and robust to several artifacts such as noisy and missing data or sudden camera motions, while it does not require any training data at all. Validation is done in a variety of real video sequences, including articulated and non-rigid motion, both for continuous and discontinuous shapes. Our system is shown to perform comparable to competing batch, computationally expensive, methods and shows remarkable improvement with respect to the sequential ones.This work was partly funded by the MINECO projects DIP2012-32168 and DPI2011-27510; by the ERA-net CHISTERA project VISEN PCIN-2013-047; by the EU Projects PopCorn FP7-SME-2013 606634 and ARCAS FP7-ICT-2011-287617; and by a scholarship FPU12/04886 of the Spanish MECD.Peer Reviewe