rnoise {spatstat.random}

Random Pixel Noise

Description

Generate a pixel image whose pixel values are random numbers following a specified probability distribution.

Usage

rnoise(rgen = runif, w = square(1), ...)

Arguments

rgen

Random generator for the pixel values. A function in the R language.

w

Window (region or pixel raster) in which to generate the image. Any data acceptable to as.mask.

...

Arguments, matched by name, to be passed to rgen to specify the parameters of the probability distribution, or passed to as.mask to control the pixel resolution.

Details

The argument w could be a window (class "owin"), a pixel image (class "im") or other data. It is first converted to a binary mask by as.mask using any relevant arguments in ....

Then each pixel inside the window (i.e. with logical value TRUE in the mask) is assigned a random numerical value by calling the function rgen.

The function rgen would typically be one of the standard random variable generators like runif (uniformly distributed random values) or rnorm (Gaussian random values). Its first argument n is the number of values to be generated. Other arguments to rgen must be matched by name.

Value

A pixel image (object of class "im").

Author(s)

Adrian Baddeley [e-mail]

Rolf Turner [e-mail]

and Ege Rubak [e-mail]

See Also

as.mask, as.im, Distributions.

Examples

  plot(rnoise(), main="Uniform noise")
  plot(rnoise(rnorm, dimyx=32, mean=2, sd=1),
       main="White noise")