imnoise: Add noise to image

In SpatialPack: Tools for Assessment the Association Between Two Spatial Processes

Add noise to image

Description

This function adds noise to an input image.

Usage

imnoise(img, type = "gaussian", mean = 0, sd = 0.01, epsilon = 0.05, var = 0.04,
       looks = 1)

Arguments

img	input grayscale image matrix.
type	character string, specifying the type of contamination: "gaussian" (Gaussian white/additive noise), "saltnpepper" (salt and pepper noise or on-off noise), "speckle" (uniform multiplicative noise) and "gamma" (gamma multiplicative noise).
mean	mean for the Gaussian noise, default value is mean = 0.
sd	standard deviation for the Gaussian noise, default value is sd = 0.01.
epsilon	contamination percentage for the salt and pepper noise with default noise density 0.05. This affects approximately epsilon% of pixels.
var	variance of uniform multiplicative noise using the equation noise = img + unif * img, with unif is uniformly distributed with mean 0 and variance var. Default value is var = 0.04.
looks	parameter of gamma multiplicative noise. The default value is looks = 1.

Value

Noisy image, returned as a numeric matrix. The imnoise function clips output pixel values to the range [0,1] after adding noise.

Examples

  data(texmos2)
  x <- imnoise(texmos2, type = "saltnpepper", epsilon = 0.10)
  plot(as.raster(x))

  y <- imnoise(texmos2, type = "speckle")
  plot(as.raster(y))

  z <- imnoise(texmos2, type = "gamma", looks = 4)
  plot(as.raster(z))

SpatialPack documentation built on Sept. 29, 2024, 5:06 p.m.