  The wide application of smart devices enables the availability of multimodal
data, which can be utilized in many tasks. In the field of multimodal sentiment
analysis (MSA), most previous works focus on exploring intra- and inter-modal
interactions. However, training a network with cross-modal information
(language, visual, audio) is still challenging due to the modality gap, and
existing methods still cannot ensure to sufficiently learn intra-/inter-modal
dynamics. Besides, while learning dynamics within each sample draws great
attention, the learning of inter-class relationships is neglected. Moreover,
the size of datasets limits the generalization ability of existing methods. To
address the afore-mentioned issues, we propose a novel framework HyCon for
hybrid contrastive learning of tri-modal representation. Specifically, we
simultaneously perform intra-/inter-modal contrastive learning and
semi-contrastive learning (that is why we call it hybrid contrastive learning),
with which the model can fully explore cross-modal interactions, preserve
inter-class relationships and reduce the modality gap. Besides, a refinement
term is devised to prevent the model falling into a sub-optimal solution.
Moreover, HyCon can naturally generate a large amount of training pairs for
better generalization and reduce the negative effect of limited datasets.
Extensive experiments on public datasets demonstrate that our proposed method
outperforms existing works.
