phonTools (version 0.1-3)

imputeformants: Impute Missing Formant Values

Description

Impute missing formant values using a least-squares approximation.

Usage

imputeformants (ffs, speaker, vowel)

Arguments

ffs

a numeric vector containing formant frequency measurements for a single formant. Values should be in Hz, and missing values need to be set to 0.

speaker

a vector indicating which unique speaker produced each formant.

vowel

a vector indicating which vowel category each formant belongs to.

Value

• A vector containing each orignal formant frequency and imputed formant frequencies where appropriate.

Details

This function finds the least-squares approximation for each missing value based on the assumption that each formant for a given vowel differs between-speakers solely on the basis on a speaker-specific multiplicative parameter. This parameter would be most closely related to gross speaker vocal-tract length.

Examples

data (h95)

## Select F2 values from the tenth speaker in H95 data
## set the first 5 values to "missing"
ffs = h95$f2
ffs[h95$speaker == 10][1:5] = 0
speaker = h95$speaker
vowel = h95$vowel

## impute these missing values
imputedf2 = imputeformants (ffs, speaker, vowel)

## resulting in a very close approximation of the original values
plot (imputedf2[h95$speaker == 10], h95$f2[h95$speaker == 10])
abline (0, 1, col = 2)