Zero Phase speech representation for robust formant tracking

In this paper we present a speech representation based on the Linear Predictive Coding of the Zero Phase version of the signal (ZP-LPC) and its robustness in presence of additive noise for robust formant estimation. Two representations are proposed for using in the frequency candidate proposition stage of the formant tracking algorithm: 1) the roots of ZP-LPC and 2) the peaks of its group delay function (GDF). Both of them are studied and evaluated in noisy environments with a synthetic dataset to demonstrate their robustness. Proposed representations are then used in a formant tracking experiment with a speech database. A beam search algorithm is used for selecting the best candidates as formant. Results show that our method outperforms related techniques in noisy test configurations and is a good fit for use in applications that have to work in noisy environments.