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Re: affine transformation to rasters

  • To: mathgroup at smc.vnet.net
  • Subject: [mg83055] Re: affine transformation to rasters
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Fri, 9 Nov 2007 05:10:10 -0500 (EST)
  • Organization: Uni Leipzig
  • References: <fguqhg$pi7$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de

Hi,

that is nonsens, try

Graphics[Table[
   GeometricTransformation[oceras,
    AffineTransform[{RandomReal[{1, 6}] {{-0.139, 0.263}, {0.246,
         0.224}}, {RandomReal[{-100, 100}],
       RandomReal[{-100, 100}]}}]], {6}]]

and you will see, that the images are translated and scaled.

But in a single image you will not see the translation/ scaling
because Mathematica will ajust the PlotRange (translation) and the
image size (scaling).

Regards
   Jens


juan flores wrote:
> Hi all,
> 
> I am working on fractals through IFS (Iterated Function Systems).  An
> IFS ca be defined as a set of affine transformations that are
> iteratively applied to an initial image.  All examples in the Wolfram
> Demonstrations Project do IFSs with polygons.  When you apply an
> affine transformation to a raster image, you get the rotations,
> reflections, and shearings right, but not the translations nor the
> scalings.
> 
> I am reading a jpg file with import, extracting the raster from it,
> and applying an affine transformation.
> 
> oce = Import["ExampleData/ocelot.jpg"];
> oceras = oce[[1]];
> Graphics[GeometricTransformation[oceras,
>   AffineTransform[{{{-0.139, 0.263},
>                             {0.246, 0.224}},
>                            {0.57, -0.036}}]]]
> 
> In this case, the affine transformation is a composition of
> translation, rotation, reflection, and shearing.
> 
> Any ideas on how to proceed?  Any tricks?
> 
> Regards,
> 
> Juan Flores
> Universidad Michoacana
> Mexico
> 
> 


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