Pitch contour parameterisation based on linear stylisation for emotion recognition

The pitch contour contains information that characterises the emotion being expressed by speech, and consequently features extracted from pitch form an integral part of many automatic emotion recognition systems. While pitch contours may have many small variations and hence are difficult to represent compactly, it may be possible to parameterise them by approximating the contour for each voiced segment by a straight line. This paper looks at such a parameterisation method in the context of emotion recognition. Listening tests were performed to subjectively determine if the linearly stylised contours were able to sufficiently capture information pertaining to emotions expressed in speech. Furthermore these parameters were used as features for an automatic 5-class emotion classification system. The use of the proposed parameters rather than pitch statistics resulted in a relative increase in accuracy of about 20%.