Facial expression recognition based on regional adaptive correlation

Abstract

Abstract To address the problem that the features extracted by CNN‐based facial expression recognition (FER) do not consider structural information, a region adaptive correlation deep network (RACN) is proposed. The network consists of two branches. In one branch, the features obtained by applying CNN to facial sub‐blocks are used as the input of the proposed second‐order region correlation network (SRCN), which obtains structural features by adaptively learning the correlation of facial regions. Furthermore, they are fused with the parallel branch‐extracted global features to obtain a comprehensive high‐semantic feature representation. Finally, weights are assigned to the two features through the channel attention mechanism for more accurate expression classification. Experimental results show that our method can effectively extract expression features in an end‐to‐end manner, improve the accuracy of FER, and achieve competitive performance without relying on any a priori knowledge. And the region‐adaptive correlation feature extraction branch RACN can be applied to other deep learning networks to extract discriminative structural‐adaptive features. To the best of our knowledge, our work is the first to enrich the feature representation for end‐to‐end static FER by adaptively obtaining more discriminative regional adaptive correlation feature vectors via the autocorrelation matrix combined with CNN compared to the existing literature.

Keywords

• computer vision
• convolutional neural nets
• correlation methods
• emotion recognition
• feature extraction
• image classification