[R] Image analysis in R?

Friedrich Leisch Friedrich.Leisch at ci.tuwien.ac.at
Thu Sep 21 09:51:02 CEST 2000

>>>>> On Thu, 21 Sep 2000 08:41:28 +0200,
>>>>> Peter Holzer (PH) wrote:

PH> Hello Bjorn
PH> I have written some functions for personal use. They allow to read and
PH> write ppm, pgm and pbm images. But I haven't put them in a package, it's
PH> just C and R code.

The e1071 package from CRAN also contains code for reading/writing
ppm, pgm and pbm images.

PH> I think that generally you will need to use C or Fortran or something else
PH> but not R for most manipulations of images (e.g. filtering), so you might
PH> just want to write an R interface to existing code. My experience
PH> is that using R code directly will make things prohibitively slow if images
PH> get large. On the other hand I appreciate writing the code first in R, where
PH> the results are easy to check, and then transform it to C.

PH> For resizing, cropping etc. I recommend `xv'.

Well, any image manipulation program should be fine (and much better
than R) for this (though cropping an image is easy: simply subset the
matrix ...)


                        Friedrich  Leisch 
Institut für Statistik                     Tel: (+43 1) 58801 10715
Technische Universität Wien                Fax: (+43 1) 58801 10798
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