efg’s R Notes: waveslim: denoise image

library(waveslim)

denoise image (denoise.dwt.2d, denoise.modwt.2d)

Perform simple de-noising of an image using the two-dimensional discrete wavelet transform.

Xbox image

data(xbox)
n <- NROW(xbox)
xbox.noise <- xbox + matrix(rnorm(n*n, sd=.15), n, n)
par(mfrow=c(1,3), cex=.8, pty="s")
image(xbox.noise, col=rainbow(128), main="Original Image")
image(denoise.dwt.2d(xbox.noise, wf="haar"), col=rainbow(128),
      zlim=range(xbox.noise), main="Denoised image")
image(xbox.noise - denoise.dwt.2d(xbox.noise, wf="haar"), col=rainbow(128),
      zlim=range(xbox.noise), main="Residual image")

Ingrid Daubechies image

data(dau)
n <- NROW(dau)
dau.noise <- dau + matrix(rnorm(n*n, sd=10), n, n)
par(mfrow=c(1,3), cex=.8, pty="s")
image(dau.noise, col=rainbow(128), main="Original Image")
dau.denoise <- denoise.modwt.2d(dau.noise, wf="d4", rule="soft")
image(dau.denoise, col=rainbow(128), zlim=range(dau.noise),
      main="Denoised image")
image(dau.noise - dau.denoise, col=rainbow(128), main="Residual image")

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packageVersion("waveslim")

## [1] '1.7.5'

efg
2015-01-31 1431