Abstract:With the prevalence of depth cameras, video data of different modalities become more common. Multi-Modal data based human action recognition attracts increasing attention. Different modal data describe human actions from distinct perspectives. How to effectively utilize the complementary information of multi-modal data is a key topic in this area. In this study, we propose a modality compensation based method for action recognition. With RGB/optical flow as source modal data and skeletons as auxiliary modal data, we aim to compensate the feature learning from source modal data, through exploring the common spaces between source and auxiliary modalities. The proposed model is based on deep convolutional neural network (CNN) and long short term memory (LSTM) network to extract spatial and temporal features. With the help of residual learning, a modality adaptation block is proposed to align the distributions of different modalities and achieve modality compensation. To deal with different alignment of source and auxiliary modal data, we propose hierarchical modality adaptation schemes. The proposed model only requires auxiliary modal data in the training process, and is able to improve the recognition performance only with source modal data in the testing phase, which expands the application scenarios of the proposed model. The experiment results illustrate that proposed method outperforms other state-of-the-art approaches.