TERNet: A deep learning approach for thermal face emotion recognition

Abstract

Facial emotion recognition technology finds numerous real-life applications in areas of virtual learning, cognitive psychology analysis, avatar animation, neuromarketing, human machine interactions, and entertainment systems. Most state-of-the-art techniques focus primarily on visible spectrum information for emotion recognition. This becomes very arduous as emotions of individuals vary significantly. Moreover, visible images are susceptible to variation in illumination. Low lighting, variation in poses, aging, and disguise have a substantial impact on the appearance of images and textural information. Even though great advances have been made in the field, facial emotion recognition using existing techniques is often not satisfactory when compared to human performance. To overcome these shortcomings, thermal images are preferred to visible images. Thermal images a) are less sensitive to lighting conditions, b) have consistent thermal signatures, and c) have a temperature distribution formed by the face vein branches. This paper proposes a robust emotion recognition system using thermal images- TERNet. To accomplish this, customized convolutional neural network(CNNs) is employed, which possess excellent generalization capabilities. The architecture adopts features obtained via transfer learning from the VGG-Face CNN model, which is further fine-tuned with the thermal expression face data from the TUFTS face database. Computer simulations demonstrate an accuracy of 96.2% when compared to the state-of-the-art models.