# R/shift.2d.R In waveslim: Basic Wavelet Routines for One-, Two- and Three-dimensional Signal Processing

```shift.2d <- function(z, inverse=FALSE) {
## "Center of Energy"
coe <- function(g) {
sum(0:(length(g)-1) * g^2) / sum(g^2)
}

wf <- attributes(z)\$wavelet
h <- wave.filter(wf)\$hpf
g <- wave.filter(wf)\$lpf

J <- (length(z) - 1) / 3
m <- nrow(z[[1]])
n <- ncol(z[[1]])

nu.H <- round(2^(1:J-1) * (coe(g) + coe(h)) - coe(g), 0)
nu.Hm <- ifelse(nu.H/m < 1, nu.H, nu.H - trunc(nu.H/m) * m)
nu.Hn <- ifelse(nu.H/n < 1, nu.H, nu.H - trunc(nu.H/n) * n)
nu.G <- round((2^(1:J) - 1) * coe(g), 0)
nu.Gm <- ifelse(nu.G/m < 1, nu.G, nu.G - trunc(nu.G/m) * m)
nu.Gn <- ifelse(nu.G/n < 1, nu.G, nu.G - trunc(nu.G/n) * n)

if (!inverse) {
## Apply the phase shifts
for (j in 0:(J-1)) {
Hm.order <- c((nu.H[j+1]+1):m, 1:nu.H[j+1])
Hn.order <- c((nu.H[j+1]+1):n, 1:nu.H[j+1])
Gm.order <- c((nu.G[j+1]+1):m, 1:nu.G[j+1])
Gn.order <- c((nu.G[j+1]+1):n, 1:nu.G[j+1])
z[[3*j+1]] <- z[[3*j+1]][Gm.order, Hn.order]
z[[3*j+2]] <- z[[3*j+2]][Hm.order, Gn.order]
z[[3*j+3]] <- z[[3*j+3]][Hm.order, Hn.order]
}
z[[3*J+1]] <- z[[3*J+1]][Gm.order, Gn.order]
} else {
## Apply the phase shifts "reversed"
for (j in 0:(J-1)) {
Hm.order <- c((m-nu.H[j+1]+1):m, 1:(m-nu.H[j+1]))
Hn.order <- c((n-nu.H[j+1]+1):n, 1:(n-nu.H[j+1]))
Gm.order <- c((m-nu.G[j+1]+1):m, 1:(m-nu.G[j+1]))
Gn.order <- c((n-nu.G[j+1]+1):n, 1:(n-nu.G[j+1]))
z[[3*j+1]] <- z[[3*j+1]][Gm.order, Hn.order]
z[[3*j+2]] <- z[[3*j+2]][Hm.order, Gn.order]
z[[3*j+3]] <- z[[3*j+3]][Hm.order, Hn.order]
}
z[[3*J+1]] <- z[[3*J+1]][Gm.order, Gn.order]
}
return(z)
}
```

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waveslim documentation built on May 2, 2019, 4:41 p.m.