Formant Estimation and Tracking

Abstract

This chapter deals with the estimation formantestimation and tracking of the movements of the spectral resonances of human formant vocal tracts, also known as formants. The representation or modeling of speech in terms of formants is useful in several areas of speech processing: coding, recognition, synthesis, and enhancement, as formants efficiently describe essential aspects of speech using a very limited set of parameters. However, estimating formants is more difficult than simply searching for peaks in an amplitude spectrum, as the spectral peaks of vocal-tract output depend upon a variety for factors in complicated ways: vocal-tract shape, excitation, and periodicity. We describe in detail the formal task of formant tracking, and explore its successes and difficulties, as well as giving reasons for the various approaches.