"Several algorithms have been developed for tracking
formant frequency trajectories of speech signals, however most of
these algorithms are either not robust in real-life noise environments
or are not suitable for real-time implementation. The algorithm
presented in this paper obtains formant frequency estimates
from voiced segments of continuous speech by using a time-varying
adaptive filterbank to track individual formant frequencies. The
formant tracker incorporates an adaptive voicing detector and a
gender detector for formant extraction from continuous speech,
for both male and female speakers. ..."