whit2 {ptw} | R Documentation |
This function smoothes signals with a finite difference penalty of order 2.
whit2(y, lambda, w)
y |
signal to be smoothed: a vector |
lambda |
smoothing parameter: larger values lead to more smoothing |
w |
weights: a vector of same length as y. Default weights are equal to one |
smoothed signal: a vector
Paul Eilers, Jan Gerretzen
Eilers, P.H.C. (2004) "Parametric Time Warping", Analytical Chemistry, 76 (2), 404 – 411.
Eilers, P.H.C. (2003) "A perfect smoother", Analytical Chemistry, 75, 3631 – 3636.
data(gaschrom) plot(gaschrom[1,], type = "l", ylim = c(0, 100)) lines(whit2(gaschrom[1,], lambda = 1e5), col = 2) lines(whit2(gaschrom[1,], lambda = 1e6), col = 3) lines(whit2(gaschrom[1,], lambda = 1e7), col = 4)