Re: usage of imread.m in octave

[Stefan van der Walt]

Hi Ole

I am not sure why you do not get a colour display.  Here, I do:

octave:3> [r,g,b] = imread('testimage.jpg');
octave:4> imshow(r,g,b)

and a colour display ImageMagick pops up.

What happens when you do

$ display /cygdrive/c/temp/testimage.jpg

from the command prompt? Are you running Octave 2.1.57?

Regards
Stefan

On Thu, Jul 15, 2004 at 11:05:30AM +0200, Ole Jacob Hagen wrote:
> Hi, Daniel.
> 
> I've tried that one (imshow(r,g,b)), but the image doesn't appear in 
> colours, just greyscale.
> 
> So I guess a fix in imread.m is required, if colour images are 
> impossible to visualise from Octave. Any volunteers?
> 
> Cheers,
> 
> Ole
> 
> Daniel J Sebald wrote:
> 
> >From what I've seen, only gray scale and color palettes (i.e., 
> >"colormap") currently work in Octave. To show a color image, you need 
> >independent primary color components, e.g., RGB. So first, you can't use
> >
> >X = imread('testimage.jpg');
> >
> >because X can't have RGB. (Unless it were a 3 dimensional matrix, 
> >which I think it isn't.) So you need something like the RGB variant:
> >
> >[r,g,b]= imread( fname );
> >
> >Then you can do an
> >
> >imshow(r,g,b);
> >
> >But, currently here is what imshow() does for the RGB
> >
> >elseif (nargin == 3)
> >[a1, a2] = rgb2ind (a1, a2, a3);
> >colormap (a2);
> >endif
> >
> >i.e., converts to an indexed image. I believe in general that can only 
> >be an approximation.
> >
> >Dan
> >
> >
> >
> 
> 



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