MFCFlow: A Motion Feature Compensated Multi-Frame Recurrent Network for Optical Flow Estimation

Occlusions have long been a hard nut to crack in optical flow estimation due to ambiguous pixels matching between abutting images. Current methods only take two consecutive images as input, which is challenging to capture temporal coherence and reason about occluded regions. In this paper, we propose a novel optical flow estimation framework, namely MFCFlow, which attempts to compensate for the information of occlusions by mining and transferring motion features between multiple frames. Specifically, we construct a Motion-guided Feature Compensation cell (MFC cell) to enhance the ambiguous motion features according to the correlation of previous features obtained by attention-based structure. Furthermore, a TopK attention strategy is developed and embedded into the MFC cell to improve the subsequent matching quality. Extensive experiments demonstrate that our MFCFlow achieves significant improvements in occluded regions and attains state-of-the-art performances on both Sintel and KITTI benchmarks among other multi-frame optical flow methods.