Micro-expression Recognition Based on PCB-PCANet+

Micro-expressions (MEs) have the characteristics of small motion amplitude and short duration. How to learn discriminative ME features is a key issue in ME recognition. Motivated by the success of PCB model in person retrieval, this paper proposes a ME recognition method called PCB-PCANet+. Considering that the important information of MEs is mainly concentrated in a few key facial areas like eyebrows and eyes, based on the output of shallow PCANet+, we use a multiple branch LSTM networks to separately learn the local spatio-temporal features for each facial ROI region. In addition, in the stage of multiple branch fusion, we design a feature weighting strategy according to the significances of different facial regions to further improve the performances of ME recognition. The experimental results on the SMIC and CASME II datasets validate the effectiveness of the proposed method.