8th European Conference on Speech Communication and Technology

Geneva, Switzerland
September 1-4, 2003


Vocal Tract Normalization as Linear Transformation of MFCC

Michael Pitz, Hermann Ney

RWTH Aachen, Germany

We have shown previously that vocal tract normalization (VTN) results in a linear transformation in the cepstral domain. In this paper we show that Mel-frequency warping can equally well be integrated into the framework of VTN as linear transformation on the cepstrum. We show examples of transformation matrices to obtain VTN warped Mel-frequency cepstral coefficients (VTN-MFCC) as linear transformation of the original MFCC and discuss the effect of Mel-frequency warping on the Jacobian determinant of the transformation matrix. Finally we show that there is a strong interdependence of VTN and Maximum Likelihood Linear Regression (MLLR) for the case of Gaussian emission probabilities.

Full Paper

Bibliographic reference.  Pitz, Michael / Ney, Hermann (2003): "Vocal tract normalization as linear transformation of MFCC", In EUROSPEECH-2003, 1445-1448.