Improved scale-cepstral analysis in speech

We present improvements over the original scale-cepstrum proposed by Umesh, Cohen, Marinovic and Nelson (see IEEE Trans. on Speech and Audio Processing, 1996). The scale-cepstrum was motivated by a desire to normalize the first-order effects of differences in vocal-tract lengths for a given vowel. Our subsequent work has shown that a more appropriate frequency-warping than the log-warping used in in the original scale-cepstrum is necessary to account for the frequency dependency of the scale-factor. Using this more appropriate frequency-warping and a modified method of computing the scale-cepstrum we have obtained improved features that provide better separability between vowels than before, and are also robust to noise