The GMM-SVM supervector approach for the recognition of the emotional status from speech

Abstract

Emotion recognition from speech is an important field of research in human-machine-interfaces, and has various applications, for instance for call centers. In the proposed classifier system RASTA-PLP features (perceptual linear prediction) are extracted from the speech signals. The first step is to compute an universal background model (UBM) representing a general structure of the underlying feature space of speech signals. This UBM is modeled as a Gaussian mixture model (GMM). After computing the UBM the sequence of feature vectors extracted from the utterance is used to re-train the UBM. From this GMM the mean vectors are extracted and concatenated to the so-called GMM supervectors which are then applied to a support vector machine classifier. The overall system has been evaluated by using utterances from the public Berlin emotional database. Utilizing the proposed features a recognition rate of 79% (utterance based) has been achieved which is close to the performance of humans on this database. © 2009 Springer Berlin Heidelberg.