  We present a method to estimate human motion in a global scene from moving
cameras. This is a highly challenging task due to the coupling of human and
camera motions in the video. To address this problem, we propose a joint
optimization framework that disentangles human and camera motions using both
foreground human motion priors and background scene features. Unlike existing
methods that use SLAM as initialization, we propose to tightly integrate SLAM
and human motion priors in an optimization that is inspired by bundle
adjustment. Specifically, we optimize human and camera motions to match both
the observed human pose and scene features. This design combines the strengths
of SLAM and motion priors, which leads to significant improvements in human and
camera motion estimation. We additionally introduce a motion prior that is
suitable for batch optimization, making our approach significantly more
efficient than existing approaches. Finally, we propose a novel synthetic
dataset that enables evaluating camera motion in addition to human motion from
dynamic videos. Experiments on the synthetic and real-world RICH datasets
demonstrate that our approach substantially outperforms prior art in recovering
both human and camera motions.
