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.

MotioNet是一种用于从单眼视频中重建 3D 人体骨骼运动的深度神经网络，通过嵌入运动先验信息的深度神经网络将 2D 关节位置序列分解为对称骨骼和与全局根位置和足接触标签相关联的 3D 关节旋转序列，并在 3D 位置上应用正向运动学，使用敌对损失确保恢复的旋转速度处于自然关节旋转曲面上的关键优势使其能够直接从训练数据中学习到自然的关节旋转。

使用骨架一致性从单目视频中重建3D人体运动