Recognizing and monitoring emotions has become more important in different research fields, such as Human-Computer Interaction (HCI), pattern recognition and computer vision, with the aim of enhancing user experience by making interactions with digital systems more effective, personalized, and empathetic. It has numerous practical applications across var- ious sectors, including medicine and psychology. In fact emotion recognition is extremely helpful for therapeutic purposes and for improving the social interpretation of emotions. For emotion recognition and monitoring many techniques can be used, for instance the EEG interpretation, the analysis of facial expressions and the study of Heart Rate Variabil- ity (HRV), depending on which emotion is considered.