  Understanding action recognition in egocentric videos has emerged as a vital
research topic with numerous practical applications. With the limitation in the
scale of egocentric data collection, learning robust deep learning-based action
recognition models remains difficult. Transferring knowledge learned from the
large-scale exocentric data to the egocentric data is challenging due to the
difference in videos across views. Our work introduces a novel cross-view
learning approach to action recognition (CVAR) that effectively transfers
knowledge from the exocentric to the selfish view. First, we present a novel
geometric-based constraint into the self-attention mechanism in Transformer
based on analyzing the camera positions between two views. Then, we propose a
new cross-view self-attention loss learned on unpaired cross-view data to
enforce the self-attention mechanism learning to transfer knowledge across
views. Finally, to further improve the performance of our cross-view learning
approach, we present the metrics to measure the correlations in videos and
attention maps effectively. Experimental results on standard egocentric action
recognition benchmarks, i.e., Charades-Ego, EPIC-Kitchens-55, and
EPIC-Kitchens-100, have shown our approach's effectiveness and state-of-the-art
performance.
