Deep Stacked Autoencoder-Based Automatic Emotion Recognition Using an Efficient Hybrid Local Texture Descriptor

Extracting an effective facial feature representation is the critical task for an automatic expression recognition system. Local binary pattern (LBP) is known to be a popular texture feature for facial expression recognition. However, only a few approaches utilize the relationship between local neighborhood pixels itself. This paper presents a hybrid local texture descriptor (HLTD) that is derived from the logical fusion of local neighborhood XNOR patterns (LNXP) and LBP to investigate the potential of positional pixel relationship in automatic emotion recognition. The LNXP encodes texture information based on two nearest vertical and/or horizontal neighboring pixel of the current pixel whereas LBP encodes the center pixel relationship of the neighboring pixel. After logical feature fusion, the deep stacked autoencoder (DSA) is established on the CK+, MMI, and KDEF-dyn dataset, and the results show that the proposed HLTD-based approach outperforms many of the state-of-the-art methods with an average recognition rate of 97.5% for CK+, 94.1% for MMI, and 88.5% for KDEF.