R help - Apr 2002 - Image processing? Manipulating image data in R?

Hi!
I am looking for a R library by which i can load images (i found pixmap that
allows it to do).
But in addition i need methods to access the data, get them for example as an
array  or matrix to do with this data some processing.
1. Is there a method in the pixmap library to access the matrix in which the
image data is stored.
2. Is there an alternative library running under MS Windows?

Sincerely 
Eryk


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wolski at molgen.mpg.de wrote:
> 
> I am looking for a R library by which i can load images...
> But in addition i need methods to access the data, get them for example as
an
> array  or matrix to do with this data some processing.
Looking at your email address and assuming that you have gene expression
data in mind, you may find the following pages useful:

 * R Packages For Gene Expression Analysis
   http://www.stat.uni-muenchen.de/~strimmer/rexpress.html

 * Spot software package for the analysis of microarray images
   http://www.cmis.csiro.au/iap/spot.htm

 * Z-IMAGE image analysis environment
   http://www.cmis.csiro.au/IAP/zimage.htm

 * Terry Speed's microarray data analysis group 
   http://www.stat.berkeley.edu/users/terry/zarray/Html/

Hope that is what you were looking for.

Greets,

  Diego Kuonen


-- 
Dr. ?s sc. Diego Kuonen        CEO & Applied Statistician 
Statoo Consulting, PO Box 107, 1015 Lausanne, Switzerland
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Besides the pixmap facilities (from the help page:
" RGB pixmaps are three-dimensional arrays ..." and
" Grey and indexed pixmaps are matrices, the element `[1,1]'
     corresponds to the upper left corner as usual."),

I use to read in images in binary raw format
using raedBin() as R matrices. From there
on you can apply any R method you want. But
note that images are often too large for R. I have
a couple of functions to display matrices as grey and rgb 
images in R with some histogram stretching to
enhance contrast. Let me know if you are interested on them.

Also, look at message to r-help:

Date: Fri, 15 Mar 2002 10:15:57 -0800
From: "Jonathan Q. Li" <jonathan_li at agilent.com>

for a very interesting R function using tcl-tk.
(let me know if you want me to forward that message to you).

Finally, note that python has an image proc. library called
PIL and R has an interface to python.

N.B: Z-IMAGE looks like a very comprehensive image processing 
package in C that can be called as Splus
(and R?) functions thanks to an specific interface, but
you must pay for it.

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 Sun, 28 Apr 2002 wolski at molgen.mpg.de wrote:
> Hi!
> I am looking for a R library by which i can load images (i found pixmap
that
> allows it to do).
> But in addition i need methods to access the data, get them for example as
an
> array  or matrix to do with this data some processing.
> 1. Is there a method in the pixmap library to access the matrix in which
the
> image data is stored.
> 2. Is there an alternative library running under MS Windows?
> 
> Sincerely 
> Eryk
> 
> 
>
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> r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
> Send "info", "help", or "[un]subscribe"
> (in the "body", not the subject !)  To: r-help-request at
stat.math.ethz.ch
>
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> 


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