Cepstral method evaluation in speech formant frequencies estimation

This paper presents a technique for formant estimation using cepstral envelope analysis. The presumed method which computes cepstrum has been implemented with Matlab and was applied to the problem of accurate measurement of formant frequencies. The conceived algorithm picks formant frequencies from the smoothed spectrum. The approach relies on decomposing the speech signal into two components: the first component presents the excitation, while the second component is intended to present vocal tract resonances. Such procedure was then achieved by applying the homomorphic deconvolution to the treated speech signal. The obtained result, i.e the cepstrum, was then used to estimate the smoothed spectrum. Formant picking is achieved by localizing the spectral maxima from the smoothed envelope. Results showed that there is a wide range in the estimated values of formant frequencies for male and female speakers. Such cepstral method evaluation confirms the limitation of the use of this technique in the estimation of formant frequencies.