Beam-Search Formant Tracking Algorithm Based on Trajectory Functions for Continuous Speech

Abstract

This paper presents a formant frequency tracking algorithm for continuous speech processing. First, it uses spectral information for generating frequency candidates. For this purpose, the roots of the polynomial of a Linear Predictive Coding (LPC) and peak picking of Chirp Group Delay Function (CGD) were tested. The second stage is a beamsearch algorithm that tries to find the best sequence of formants given the frequency candidates, applying a cost function based on local and global evidences. The main advantage of this beam-search algorithm compared with previous dynamic programming approaches lies in that a trajectory function that takes into account several frames can be optimally incorporated to the cost function. The performance was evaluated using a labeled formant database and the Wavesurfer formant tracker, achieving promising results.