Speaker normalization is carried out based on biometric information
available about a speaker, such as his height, or a dimension of a bodily
member or article of clothing. The chosen biometric parameter correlates
with the vocal tract length. Speech can be normalized based on the
biometric parameter, which thus indirectly normalizes the speech based on
the vocal tract length of the speaker. The inventive normalization can be
used in model formation, or in actual speech recognition usage, or both.
Substantial improvements in accuracy have been noted at little cost. The
preferred biometric parameter is height, and the preferred form of scaling
is linear scaling with the scale factor proportional to the height of the
speaker.
