[R] gif, jpeg and png image files reader

[Agustin Lobo]

Jonathan,

Although I see your point, perhaps developing a
comprehensive package in R for image processing would not be
the best solution. We cannot expect R to do
everything. From my point of view, a transparent
link to other gnu software might be better. This is
also the case for GIS, which although very useful
in combination with R, is not really statistics.
R is already very large, so much that we are all
beginers as soon as we move a bit from what we
normally do. I'd be careful at increasing
heterogeneity too much, because maintenace, management,
documentation... might become impossible. The
R team, to whom all R users must be thankful, already
has a phenomenal task.

If you need to import many images, you can use 
packages that transform from the command
line, so you can make an R function that
transforms the images to pnm using system(), and
then use the pixmap functions. 

I've made some functions to have a minimal 
functionality in R to display and explore 
matrices as images (grey and rgb). Let me
know if these could help you.

A better approach might be using the 
new RPy, as Python has an image processing
library (PIL). It used to have as well an
extensive image processing add-on, called
PythonMagick, but I think that this
is no longer available.

Agus


Dr. Agustin Lobo
Instituto de Ciencias de la Tierra (CSIC)
Lluis Sole Sabaris s/n
08028 Barcelona SPAIN
tel 34 93409 5410
fax 34 93411 0012
alobo at ija.csic.es


On Tue, 12 Mar 2002, Jonathan Q. Li wrote:

> Yah, but what if I need to write a package in R that reads these images?
> It's
> too much manual trouble to use outside software. It's especially infeasible
> if
> these become a routine task with many images.
> I think that here may be a place to make an improvement to R.
> I, for one, can certainly appreciate the use of such reader functions. Are
> there any one else
> who felt the same way?
> 
> Jonathan
> 
> -----Original Message-----
> From: Roger Peng [mailto:rpeng at stat.ucla.edu]
> Sent: Monday, March 11, 2002 5:43 PM
> To: jonathan_li at agilent.com
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] gif, jpeg and png image files reader
> 
> 
> The pixmap package has functions for reading pnm (portable anymap) files,
> but you still need an outside software to convert (like ImageMagick).
> 
> -roger
> _______________________________
> UCLA Department of Statistics
> rpeng at stat.ucla.edu
> http://www.stat.ucla.edu/~rpeng
> 
> On Mon, 11 Mar 2002, jonathan_li at agilent.com wrote:
> 
> > Hi all,
> >
> > Although R seems to have jpeg() and png() functions that converts data
> into
> > jpeg and png formated files, it
> > doesn't have functions the other way around.
> > Does one of R contributed packages have gif, jpeg and png image readers? I
> > did help.search() but no luck
> >
> > Regards,
> > Jonathan
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