A Boost in Revealing Subtle Facial Expressions: A Consolidated Eulerian Framework

Facial Micro-expression Recognition (MER) distinguishes the underlying emotional states of spontaneous subtle facial expressions. Automatic MER is challenging because that the intensity of subtle facial muscle movement is extremely low and the duration of ME is transient.Recent works adopt motion magnification or temporal interpolation to resolve these issues. Nevertheless, existing works divide them into two separate modules due to their non-linearity. Though such operation eases the difficulty in implementation, it ignores their underlying connections and thus results in inevitable losses in both accuracy and speed. Instead, in this paper, we propose a consolidated Eulerian framework to reveal the subtle facial movements. It expands the temporal duration and amplifies the muscle movements in micro-expressions simultaneously. Compared to existing approaches, the proposed method can not only process ME clips more efficiently but also make subtle ME movements more distinguishable. Experiments on two public MER databases indicate that our model outperforms the state-of-the-art in both speed and accuracy.