Multi-modal Fusion for Continuous Emotion Recognition by Using Auto-Encoders

Abstract

Human stress detection is of great importance for monitoring mental health. The Multimodal Sentiment Analysis Challenge (MuSe) 2021 focuses on emotion, physiological-emotion, and stress recognition as well as sentiment classification by exploiting several modalities. In this paper, we present our solution for the Muse-Stress sub-challenge. The target of this sub-challenge is continuous prediction of arousal and valence for people under stressful conditions where text transcripts, audio and video recordings are provided. To this end, we utilize bidirectional Long Short-Term Memory (LSTM) and Gated Recurrent Unit networks (GRU) to explore high-level and low-level features from different modalities. We employ Concordance Correlation Coefficient (CCC) as a loss function and evaluation metric for our model. To improve the unimodal predictions, we add difficulty indicators of the data obtained by using Auto-Encoders. Finally, we perform late fusion on our unimodal predictions in addition to the difficulty indicators to obtain our final predictions. With this approach, we achieve CCC of 0.4278 and 0.5951 for arousal and valence respectively on the test set, our submission to MuSe 2021 ranks in the top three for arousal, fourth for valence, and in top three for combined results.