SceNeRFlow: Time-Consistent Reconstruction of General Dynamic Scenes
Authors: name: Edith Tretschk, name: Vladislav Golyanik, name: Michael Zollhoefer, name: Aljaz Bozic, name: Christoph Lassner, name: Christian Theobalt

Existing methods for the 4D reconstruction of general, non-rigidly deforming
objects focus on novel-view synthesis and neglect correspondences. However,
time consistency enables advanced downstream tasks like 3D editing, motion
analysis, or virtual-asset creation. We propose SceNeRFlow to reconstruct a
general, non-rigid scene in a time-consistent manner. Our dynamic-NeRF method
takes multi-view RGB videos and background images from static cameras with
known camera parameters as input. It then reconstructs the deformations of an
estimated canonical model of the geometry and appearance in an online fashion.
Since this canonical model is time-invariant, we obtain correspondences even
for long-term, long-range motions. We employ neural scene representations to
parametrize the components of our method. Like prior dynamic-NeRF methods, we
use a backwards deformation model. We find non-trivial adaptations of this
model necessary to handle larger motions: We decompose the deformations into a
strongly regularized coarse component and a weakly regularized fine component,
where the coarse component also extends the deformation field into the space
surrounding the object, which enables tracking over time. We show
experimentally that, unlike prior work that only handles small motion, our
method enables the reconstruction of studio-scale motions.