MotioNet: 3D Human Motion Reconstruction from Monocular Video with Skeleton Consistency

Fuente: arXiv
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Main Authors: Shi, Mingyi, Aberman, Kfir, Aristidou, Andreas, Komura, Taku, Lischinski, Dani, Cohen-Or, Daniel, Chen, Baoquan
Format: Preprint
Published: 2020
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author Shi, Mingyi
Aberman, Kfir
Aristidou, Andreas
Komura, Taku
Lischinski, Dani
Cohen-Or, Daniel
Chen, Baoquan
author_facet Shi, Mingyi
Aberman, Kfir
Aristidou, Andreas
Komura, Taku
Lischinski, Dani
Cohen-Or, Daniel
Chen, Baoquan
contents We introduce MotioNet, a deep neural network that directly reconstructs the motion of a 3D human skeleton from monocular video.While previous methods rely on either rigging or inverse kinematics (IK) to associate a consistent skeleton with temporally coherent joint rotations, our method is the first data-driven approach that directly outputs a kinematic skeleton, which is a complete, commonly used, motion representation. At the crux of our approach lies a deep neural network with embedded kinematic priors, which decomposes sequences of 2D joint positions into two separate attributes: a single, symmetric, skeleton, encoded by bone lengths, and a sequence of 3D joint rotations associated with global root positions and foot contact labels. These attributes are fed into an integrated forward kinematics (FK) layer that outputs 3D positions, which are compared to a ground truth. In addition, an adversarial loss is applied to the velocities of the recovered rotations, to ensure that they lie on the manifold of natural joint rotations. The key advantage of our approach is that it learns to infer natural joint rotations directly from the training data, rather than assuming an underlying model, or inferring them from joint positions using a data-agnostic IK solver. We show that enforcing a single consistent skeleton along with temporally coherent joint rotations constrains the solution space, leading to a more robust handling of self-occlusions and depth ambiguities.
format Preprint
id arxiv_https___arxiv_org_abs_2006_12075
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle MotioNet: 3D Human Motion Reconstruction from Monocular Video with Skeleton Consistency
Shi, Mingyi
Aberman, Kfir
Aristidou, Andreas
Komura, Taku
Lischinski, Dani
Cohen-Or, Daniel
Chen, Baoquan
Computer Vision and Pattern Recognition
Graphics
Machine Learning
I.4.5
We introduce MotioNet, a deep neural network that directly reconstructs the motion of a 3D human skeleton from monocular video.While previous methods rely on either rigging or inverse kinematics (IK) to associate a consistent skeleton with temporally coherent joint rotations, our method is the first data-driven approach that directly outputs a kinematic skeleton, which is a complete, commonly used, motion representation. At the crux of our approach lies a deep neural network with embedded kinematic priors, which decomposes sequences of 2D joint positions into two separate attributes: a single, symmetric, skeleton, encoded by bone lengths, and a sequence of 3D joint rotations associated with global root positions and foot contact labels. These attributes are fed into an integrated forward kinematics (FK) layer that outputs 3D positions, which are compared to a ground truth. In addition, an adversarial loss is applied to the velocities of the recovered rotations, to ensure that they lie on the manifold of natural joint rotations. The key advantage of our approach is that it learns to infer natural joint rotations directly from the training data, rather than assuming an underlying model, or inferring them from joint positions using a data-agnostic IK solver. We show that enforcing a single consistent skeleton along with temporally coherent joint rotations constrains the solution space, leading to a more robust handling of self-occlusions and depth ambiguities.
title MotioNet: 3D Human Motion Reconstruction from Monocular Video with Skeleton Consistency
topic Computer Vision and Pattern Recognition
Graphics
Machine Learning
I.4.5
url https://arxiv.org/abs/2006.12075