Improvements in estimating the harmonics-to-noise ratio of the voice

An improved algorithm for computing harmonics-to-noise ratio (HNR) of the voice was developed and tested using synthesized vowels at various fundamental frequencies and known HNR values. The described algorithm implements a stringent routine for the identification of pitch pulse boundary markers based on a combination of peak-picking and zero-crossing procedures. Results showed mean absolute errors between computed versus expected HNR to be < 2 dB, a significant improvement over previously reported methods. Computational errors were minimized most effectively with vowel samples in the range of 17 to -10 dB HNR. Normative data for young adult males and females indicate that HNR < 13 dB may be considered abnormal in a majority of cases.