Thread Subject: save overlay image

Hi folks,

I've used the following code to display an image overlay on top of another. It works fine and I get the desired result.

------------------------------------------------
bgim = imagesc(bg);
axis off
hold on

% Overlay the image, and set the transparency previously calculated
ovly = imagesc(im);
set(ovly,'AlphaData',imAlphaData);
------------------------------------------------

I have a button in the GUI to export the image. However I'm re-plotting the images in a new figure window and using saveas, this has the drawback that it's only the resolution of the figure window and the images are actually 1504x1000. I'd like to use imwrite to output the full image as a .png but I don't know how to 'flatten' these two matrices into 1 layer. Hope that's clear enough.

Thanks in advance!

"Oliver" wrote:
> Hi folks,
>
> I've used the following code to display an image overlay on top of another. It works fine and I get the desired result.
>
> ------------------------------------------------
> bgim = imagesc(bg);
> axis off
> hold on
>
> % Overlay the image, and set the transparency previously calculated
> ovly = imagesc(im);
> set(ovly,'AlphaData',imAlphaData);
> ------------------------------------------------
>
> I have a button in the GUI to export the image. However I'm re-plotting the images in a new figure window and using saveas, this has the drawback that it's only the resolution of the figure window and the images are actually 1504x1000. I'd like to use imwrite to output the full image as a .png but I don't know how to 'flatten' these two matrices into 1 layer. Hope that's clear enough.
>
> Thanks in advance!

If the two images are the same size then you can flatten them programmatically, rather than in a figure. An example of doing this is given in this answer:
http://www.mathworks.com/matlabcentral/answers/9588-multiple-colormaps-freezecolors-won-t-work
You can then use imwrite on the output.

Ah you hero! that works a treat!

Now I've just got to figure out how to get a colour bar scale into the full res exported image.... I might be back with some more questions!

"Oliver" wrote:
> Ah you hero! that works a treat!
>
> Now I've just got to figure out how to get a colour bar scale into the full res exported image.... I might be back with some more questions!

Have you seen SC?:
http://www.mathworks.com/matlabcentral/fileexchange/16233-sc-powerful-image-rendering
It has a couple of colormaps you might find useful for your particular problem - prob and prob_jet. Generate a figure with the image and the colorbar in, then try using export_fig:
http://www.mathworks.com/matlabcentral/fileexchange/23629-exportfig
with the -native option to get the correct image resolution.