Is there any way to make this code faster?
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Hi, I have this code that tosses out pixels from a cc list
for i = 1:cc.NumObjects
for j = length(cc.PixelIdxList{i}):-1:1
ind = cc.PixelIdxList{i}(j);
if ~imdiff(ind) || ~imcombined(ind)
cc.PixelIdxList{i}(j) = [];
end
end
end
imdiff and imcombined are both images. The code at the moment takes quite a while to churn through a decent sized image. Is there any way to make this code run faster?
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Akzeptierte Antwort
Daniel Shub
am 17 Jul. 2012
I think this is a memory allocation issue. Every time you set cc.PixelIdxList{i}(j) = [], MATLAB needs to allocate new memory. You might be better off building an array that holds the indices to remove, and then removing them at the end.
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Weitere Antworten (1)
Sean de Wolski
am 17 Jul. 2012
Bearbeitet: Sean de Wolski
am 17 Jul. 2012
That whole thing should be vectorizable assuming imdiff and imcombined (whatever those are) can handle it:
cellfun(@(c)c(imdiff(c)&imcombined(c)),CC.PixelIdxList,'uni',false)
3 Kommentare
Sean de Wolski
am 17 Jul. 2012
No. I just like it :)
You could keep the outer for-loop just as easily. The point is that the inner for-loop does not need to check each value if imdiff and imcombined are either images or functions that can be passed vector inputs.
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