Compensated mel frequency cepstrum coefficients

The high concentration of energy in the low frequency range observed for most speech spectra is considered a nuisance because it makes less relevant the energy of the signal at middle and high frequencies in many speech analysis algorithms. This problem is often partially solved by filtering the input signal with a single-zero high pass filter. This technique, known as pre-emphasis, is not used in some speech recognition systems because it can increase the noise energy at high frequencies, which in some cases degrades the system´s performance. A new algorithm, to avoid the ill effects of pre-emphasis, is presented in this paper. It is shown that this approach can increase the recognition rate