MTSN: A Multi-Temporal Stream Network for Spotting Facial Macro- and Micro-Expression with Hard and Soft Pseudo-labels

This paper considers the challenge of spotting facial macro- and micro-expression from long videos. We propose the multi-temporal stream network (MTSN) model that takes two distinct inputs by considering the different temporal information in the facial movement. We also introduce a hard and soft pseudo-labeling technique to enable the network to distinguish expression frames from non-expression frames via the learning of salient features in the expression peak frame. Consequently, we demonstrate how a single output from the MTSN model can be post-processed to predict both macro- and micro-expression intervals. Our results outperform the MEGC 2022 baseline method significantly by achieving an overall F1-score of 0.2586 and also did remarkably well on the MEGC 2021 benchmark with an overall F1-score of 0.3620 and 0.2867 on CAS(ME)2 and SAMM Long Videos, respectively.