Joint 3D Human Motion Capture and Physical Analysis From Monocular Videos

Petrissa Zell, Bastian Wandt, Bodo Rosenhahn; Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR) Workshops, 2017, pp. 17-26

Motion analysis is often restricted to a laboratory setup with multiple cameras and force sensors which requires expensive equipment and knowledgeable operators. Therefore it lacks in simplicity and flexibility. We propose an algorithm combining monocular 3D pose estimation with physics-based modeling to introduce a statistical framework for fast and robust 3D motion analysis from 2D video-data. We use a factorization approach to learn 3D motion coefficients and join them with physical parameters, that describe the dynamic of a mass-spring-model. Our approach does neither require additional force measurement nor torque optimization and only uses a single camera while allowing to estimate unobservable torques in the human body. We show that our algorithm improves the monocular 3D reconstruction by enforcing plausible human motion and resolving the ambiguity of camera and object motion. The performance is evaluated on different motions and multiple test data sets as well as on challenging outdoor sequences.