[R] Image processing? Manipulating image data in R?

[Agustin Lobo]

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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