Display image inside parfor loop

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Nima Mojtahedi
Nima Mojtahedi on 5 Aug 2014
Answered: Edric Ellis on 6 Aug 2014
Dear Experts I am doing Parallel computation in matlab and I use simple parfor but inside of parfor I need to use imshow function. But matlab stopped by Error using imshow (line 208) IMSHOW unable to display image. I searched for solution and just I found batch work. Actually I couldn't used batch inside parfor. I put my code here and I appreciate if somebody can help me.
parfor i=5:nuframe
ts=read(video,i);
org_img=ts(:,:,1);
hisq_img=histeq(org_img);
imshow(hisq_img);
end

Accepted Answer

Ben11
Ben11 on 5 Aug 2014
I'm afraid you can't control image display inside a parfor loop, i.e. inside individual workers. However you can store all the images in a temporary array/cell array/whatever and wait until the parfor loop terminates before displaying them.
  2 Comments
Nima Mojtahedi
Nima Mojtahedi on 5 Aug 2014
The problem is that this is good idea for small size of data, when I use long video actually this is not possible. Any solution for huge amount of data?
Best, Nima
Ben11
Ben11 on 5 Aug 2014
Mhh maybe allow some case inside the parfor loop in which you exit the loop to display some frames and then come back inside the loop? This is just an idea though I don't know if it's possible.

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More Answers (1)

Edric Ellis
Edric Ellis on 6 Aug 2014
One option is to use PARFEVAL and display the images back at the host when they're ready. Here's an example: http://blogs.mathworks.com/loren/2013/12/09/getting-data-from-a-web-api-in-parallel/

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