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Re: how to write an ImageEffect filter?

• To: mathgroup at smc.vnet.net
• Subject: [mg106472] Re: [mg106458] how to write an ImageEffect filter?
• From: Patrick Scheibe <pscheibe at trm.uni-leipzig.de>
• Date: Thu, 14 Jan 2010 05:46:03 -0500 (EST)
• References: <201001131058.FAA06888@smc.vnet.net>

Hi,

do it yourself:

AddPoissonNoise[img_Image?(ImageChannels[#] === 1 &), \[Lambda]_] := 
 Image[Map[ Min[255, #] &,
   ImageData[img, "Byte"] + 
    RandomInteger[PoissonDistribution[\[Lambda]], 
     ImageDimensions[img]], {2}], "Byte"]

img = Image[
  Graphics[{Gray, Disk[]}, Background -> Black, ImageSize -> 128], 
  "Byte", ColorSpace -> "Grayscale"]
noiseimg = AddPoissonNoise[img, 10]
ImageAdjust@ImageSubtract[noiseimg, img]

Cheers
Patrick

On Wed, 2010-01-13 at 05:58 -0500, sibir wrote:
> The function ImageEffect allows to add noise to an image, however the
> options are very limited: only uniform, Gaussian and salt&pepper. I
> need to add Poisson noise. it should be straitforward to to create
> that filter by modifying the Gaussian, but I am not bale to find any
> documentation.
> 
> Anybody out there with a clue?
> 

• References:
  • how to write an ImageEffect filter?
    • From: sibir <martin.rommel@gmail.com>