  Self-supervised monocular scene flow estimation, aiming to understand both 3D
structures and 3D motions from two temporally consecutive monocular images, has
received increasing attention for its simple and economical sensor setup.
However, the accuracy of current methods suffers from the bottleneck of
less-efficient network architecture and lack of motion rigidity for
regularization. In this paper, we propose a superior model named EMR-MSF by
borrowing the advantages of network architecture design under the scope of
supervised learning. We further impose explicit and robust geometric
constraints with an elaborately constructed ego-motion aggregation module where
a rigidity soft mask is proposed to filter out dynamic regions for stable
ego-motion estimation using static regions. Moreover, we propose a motion
consistency loss along with a mask regularization loss to fully exploit static
regions. Several efficient training strategies are integrated including a
gradient detachment technique and an enhanced view synthesis process for better
performance. Our proposed method outperforms the previous self-supervised works
by a large margin and catches up to the performance of supervised methods. On
the KITTI scene flow benchmark, our approach improves the SF-all metric of the
state-of-the-art self-supervised monocular method by 44% and demonstrates
superior performance across sub-tasks including depth and visual odometry,
amongst other self-supervised single-task or multi-task methods.
