In a logical array index the area with the most TRUE values
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Below I have a logical vector:
t=[0 1 0 0 0 0 1 1 0 0 1 1 1 1 1 1 1 1 1 1 0 1 0 0 0 1 0];
which has 5 TRUE areas and 6 FALSE areas. The 3rd TRUE area has the most TRUE elements of all TRUE areas.
How can I index it logically? To be more specific I want to get the following result:
t=[0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0];
Thank you!
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Accepted Answer
Andrei Bobrov
on 18 Aug 2013
Edited: Andrei Bobrov
on 18 Aug 2013
t=[0 1 0 0 0 0 1 1 0 0 1 1 1 1 1 1 1 1 1 1 0 1 0 0 0 1 0];
ii = 3;
out = cumsum([false;diff(t(:))==1]) == 3 & t(:);
or
a = cumsum([false;diff(t(:))==1]);
aa = a(t>0);
[~,ii]=max(histc(aa,unique(aa))); % or: [~,ii]=max(accumarray(aa,aa,[],@numel));
out = a == 3 & t(:);
or with Image Processing Toolbox
C = bwlabel(t);
Z = regionprops(C,'Area');
[~,ii] = max([Z.Area]);
out = C == ii;
or mix
[~,ii] = min(strfind([0,t(:)'],[0 1])-strfind([t(:)',0],[1 0]));
out = ii == bwlabel(t(:)');
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More Answers (1)
Azzi Abdelmalek
on 13 Aug 2013
Edited: Azzi Abdelmalek
on 13 Aug 2013
t=[0 1 0 0 0 0 1 1 0 0 1 1 1 1 1 1 1 1 1 1 0 1 0 0 0 1 0];
a=find(diff([0 t 0]));
idx1=a(1:2:end);
idx2=a(2:2:end)-1;
[~,nmax]=max(idx2-idx1);
t=zeros(1,numel(t));
t(idx1(nmax):idx2(nmax))=1
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