R/temporalwhiten.R

In stnava/itkImageR: Examples using Rcpp to interface R and ITK

temporalwhiten <- function(mat, myord = 2) {
  if (nargs() == 0) {
    print("Usage:  x_whitened<-whiten( x ) ")
    return(1)
  }
  omat <- mat
  for (i in 1:ncol(mat)) {
    gsig <- mat[, i]
    arval <- rep(0, myord)
    try(arval <- ar(gsig, FALSE, myord)$ar)
    omat[, i] <- shift(gsig, 1) * arval[1] + shift(gsig, 2) * arval[2]
  }
  return(omat)
}