could you fix these codes?
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I=imread('filename');
a1=I(1:8,1:8);
a2=I(1:8,9:16);
a3=I(1:8,17:24);
a4=I(1:8,25:32);
b1=I(9:16,1:8);
b2=I(9:16,9:16);
b3=I(9:16,17:24);
b4=I(9:16,25:32);
c1=I(17:24,1:8);
c2=I(17:24,9:16);
c3=I(17:24,17:24);
c4=I(17:24,25:32);
d1=I(25:32,1:8);
d2=I(25:32,9:16);
d3=I(25:32,17:24);
d4=I(25:32,25:32);
could you tell me how to make it short? Thank you
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Réponse acceptée
Jan
le 14 Mai 2013
Modifié(e) : Jan
le 14 Mai 2013
Don't do this.
Hiding the index in the name of a variable is a bad programming pattern. It is much more efficient to use indices as indices:
img = reshape(a(1:32, 1:32), 8, 4, 8, 4);
img = permute(img, [1,3,2,4]);
Now you have img(:, :, 1, 1) instead of a1.
This is much faster, needs less memory, and allows to expand the method for millions of tiles easily.
3 commentaires
Image Analyst
le 16 Mai 2013
You may not even need to do that. It's possible that you do not need to even store the tiles at all. Do you? Why do these tiles need to be stored rather than just operated on and thrown away (reused)? Just operate on one tile at a time if you can - why store forever?
Plus de réponses (2)
Iman Ansari
le 14 Mai 2013
Modifié(e) : Iman Ansari
le 14 Mai 2013
Hi. Use cell array:
I=imread('moon.tif');
C=mat2cell(I(1:32,1:32),8*ones(1,4),8*ones(1,4));
imshow(C{5},'InitialMagnification','fit')
C{5} or C{1,2} is a2 in your code.
3 commentaires
Iman Ansari
le 14 Mai 2013
It's not good having variable named a1,a2,..., see this:
I=imread('moon.tif');
C=mat2cell(I(1:32,1:32),8*ones(1,4),8*ones(1,4));
imshow(C{5},'InitialMagnification','fit')
C in this code is:
C={a1,a2,a3,a4;b1,b2,b3,b4;c1,c2,c3,c4;d1,d2,d3,d4}
and for s:
s=[C{1,1} C{2,1} C{3,2} C{4,3};C{1,3} C{2,2} C{3,3} C{4,4};...]
David Sanchez
le 14 Mai 2013
You can try as well something like this
I=imread(your_32x32_image_name);
division = 8; % set according to yuor needs
L = size(I,1)/division;
subI = cell( L,L );
for row=1:L
for col=1:L
subI{row,col} = I( (row:row*division),(col:(col*division)) );
end
end
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