Vowel formant track normalization using discrete cosine transform coefficients

This paper provides an overview of the discrete cosine transform (DCT) as a method for smoothing vowel formant tracks, as well as a procedure to take any speaker normalization method that has been defined for formant point measurements and define an equivalent method to be applied directly to DCT coefficients. This procedure is followed for three established normalization methods, and the difference between DCT normalization and formant point normalization is found to be marginal.