DUAL: A Dual‐Stage Approach for Facial Expression Recognition Based on Contrastive Learning

Facial expression recognition (FER) remains a challenging task in computer vision. Recent works have shown excellent performance in overall recognition accuracy, but its accuracy significantly decreases when recognizing similar expressions. This is due to interclass homogeneity and intraclass heterogeneity. To address these issues, we propose a novel dual‐stage network called DUAL, inspired by contrastive learning. First, we increase the distance between negative samples while reducing the distance between positive ones. This is achieved by dynamically updating pairs of comparison samples. Second, we introduce a two‐stage network architecture. The first stage uses two branches to extract image features and facial keypoint features. These branches interact to learn coarse‐grained features through mutual guidance. The second stage focuses on fine‐grained features using scale‐specific residual blocks. This allows the model to identify facial regions that are critical for recognizing expressions. We conducted extensive experiments on multiple datasets. The results show that DUAL surpasses state‐of‐the‐art models in items of performance. Additionally, the model shows high accuracy even in noisy conditions, highlighting its robustness.