Improvements of the harmonic-sieve pitch extraction scheme and an appropriate method for voiced-unvoiced detection

Continued investigations on the harmonic-sieve pitch extractor have led to several major improvements, such as e.g. even less frequent occurrence of pitch errors, especially for speech with low pitch, and extreme robustness with respect to low-frequency cut-off in the input speech. Additionally, a voiced-unvoiced detector is presented which is based on tracking of spectral intensity variations of subsequent speech segments. It can be incorporated in the pitch extractor with very little overhead.