Spatio-temporal deformable 3D ConvNets with attention for action recognition

The irregularity of human actions poses great challenges in video action recognition. Recently, 3D ConvNet methods have shown promising performance at modelling the motion and appearance information. However, the fixed geometric structure of 3D convolution filters largely limits the learning capacity for video action recognition. To address this problem, this paper proposes a spatio-temporal deformable ConvNet module with an attention mechanism, which takes into consideration the mutual correlations in both temporal and spatial domains, to effectively capture the long-range and long-distance dependencies in the video actions. Our attention based deformable module, as a generic module for 3D ConvNets, can adaptively learn more accurate spatio-temporal offsets to model the action irregularity. The experiments on two popular datasets (UCF-101 and HMDB-51) demonstrate that our module significantly outperforms the state-of-the-art methods. (C) 2019 Elsevier Ltd. All rights reserved.