Cmf-transformer: cross-modal fusion transformer for human action recognition

In human action recognition, both spatio-temporal videos and skeleton features alone can achieve good recognition performance, however, how to combine these two modalities to achieve better performance is still a worthy research direction. In order to better combine the two modalities, we propose a novel Cross-Modal Transformer for human action recognition—CMF-Transformer, which effectively fuses two different modalities. In spatio-temporal modality, video frames are used as inputs and directional attention is used in the transformer to obtain the order of recognition between different spatio-temporal blocks. In skeleton joint modality, skeleton joints are used as inputs to explore more complete correlations in different skeleton joints by spatio-temporal cross-attention in the transformer. Subsequently, a multimodal collaborative recognition strategy is used to identify the respective features and connectivity features of two modalities separately, and then weight the identification results separately to synergistically identify target action by fusing the features under the two modalities. A series of experiments on three benchmark datasets demonstrate that the performance of CMF-Transformer in this paper outperforms most current state-of-the-art methods.