"blockproc" with more than one output image
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Hello!
I'm using blockproc from the image processing toolbox for processing some large images.
Is it possible to output more than one image? My prossing function returns two versions of the processed image, and I would like to save both.
Is there any way to do so?
BTW: Why does blockproc work single-threaded? It could easily create a new thread for each single block, as long as there are enough system resources (CPU cores and memory).
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Answers (3)
Walter Roberson
on 1 Jun 2011
Creating a new thread has a lot of overhead. It does not become worthwhile until you are working with somewhere over 5000 array elements.
It appears to me that you could concatenate the two processed images together and return that, and then afterwards pull out the appropriate stripes.
The version of MATLAB that I use is not new enough to have blockproc() so I cannot test; it appears to me that possibly your "fun" could return a cell array.
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Sean de Wolski
on 1 Jun 2011
As long as the concatenation is along the first or second dimension, it can't concatenate along the third. It cannot convert to cell.
R2009b
Walter Roberson
on 1 Jun 2011
Yes, I was thinking of horzcat() in particular, and afterwards selecting the columns for each of the stripes. Though the de-interleaving would be made easier if the "fun" output the two images interleaved in alternate columns: then image1 could be pulled out as I(:,1:2:end)
Image Analyst
on 2 Jun 2011
I guess I'm not sure what you're asking. What do you mean by "output two images"? So your "prossing function" (which may use blockproc internally, but so what) returns two images as two output arguments, and these are accepted by your calling routine. So go ahead and save them - you can use imwrite(). Again, not sure why you have a question about that. Why should blockproc have anything to do with saving those images? Or are you saying that your function called by blockproc returns two variables (either scalars or arrays) and that you want to take those and stick them into two different images that you're building up? You might need to explain in more detail (at least for me).
Lemar DeSalis
on 3 Jun 2011
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Sean de Wolski
on 3 Jun 2011
You might also think about using the fourth dimension to stack RGB images. This is the way it's typically done in MATLAB.
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