calc.zerocoef {ptw}

Correction for warping coefficients when using zeropadding

Description

This function calculates the warping coefficients for the original range of the data, based on the warping of zero-filled data. Only needed when zeros are added in the beginning of the signal.

Usage

calc.zerocoef(coef, zeros)

Arguments

coef

vector of warping coefficients of a PTW-calculation on a set of signals with zeros added to the beginning of the signal

zeros

the number of zeros added

Value

a vector containing the corrected warping coefficients

Author(s)

Jan Gerretzen

References

Bloemberg, T.G., et al. (2010) "Improved parametric time warping for Proteomics", Chemometrics and Intelligent Laboratory Systems, 104 (1), 65 – 74.

See Also

padzeros calc.multicoef

Examples

data(gaschrom)
gaschrom.zf <- padzeros(gaschrom, 250)
ref <- gaschrom[1,]
samp <- gaschrom[16,]
ref.zf <- gaschrom.zf[1,]
samp.zf <- gaschrom.zf[16,]
gaschrom.ptw <- ptw(ref.zf, samp.zf)
layout(matrix(1:2,2,1, byrow=TRUE))
plot(gaschrom.ptw)
corr.coef <- calc.zerocoef(gaschrom.ptw$warp.coef, 250)
gaschrom.ptw2 <- ptw(ref, samp, init.coef = corr.coef, try = TRUE)
plot(gaschrom.ptw2)