MotionRefineNet: Fine-Grained Pose Sequence Smoothing and Refinement

Capturing human motion with existing monocular estimators often results in large errors when dealing with rare poses, occlusions, truncations, and frame blurring, leading to jitter and long-term drift. Although previous methods have introduced post-processing networks for pose refinement, they struggle to balance global smoothing and fine-grained correction. In this work, we propose MotionRefineNet, which leverages the synergy and complementarity between long- and short-term features in the temporal domain and high- and low-frequency features in the frequency domain to address these challenges. The temporal branch is designed as a hierarchical motion structure to learn multi-time scale features, where long-term features learn motion smoothness, and short-term features capture local rapid changes. The frequency branch employs different frequency band learning strategies based on the degrees of freedom (DoF) of body parts. For body parts with low DoF, the focus is on low-frequency features that represent overall motion trends and regular actions. For body parts with high DoF, we design a filter to adaptively extract useful information from all frequency bands, including subtle motion changes in the high-frequency bands. Extensive experiments on multiple datasets and estimators demonstrate that MotionRefineNet outperforms existing methods in refining 2D, 3D, and SMPL poses, achieving superior pose smoothing and deviation correction. Our code is available at: https://github.com/Wheels319/MotionRefineNet.