Review of Automatic Estimation of Emotions in Speech

Identification of emotions exhibited in utterances is useful for many applications, e.g., assisting with handling telephone calls or psychological diagnoses. This paper reviews methods to identify emotions from speech signals. We examine the information in speech that helps to estimate emotion, from points of view involving both production and perception. As machine approaches to recognize emotion in speech often have much in common with other speech tasks, such as automatic speaker verification and speech recognition, we compare such processes. Many methods of emotion recognition have been found in research on pattern recognition in other areas, e.g., image and text recognition, especially in recent methods for machine learning. We show that speech is very different compared to most other signals that can be recognized, and that emotion identification is different from other speech applications. This review is primarily aimed at non-experts (more algorithmic detail is present in the cited literature), but this presentation has much discussion for experts as well.