How do I divide an image into blocks for processing?
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I am new to MATLAB.
I am trying to write code which will divide the image in nonoverlaping blocks of size 3*3. I am supposed to do operations on specific blocks like getting the value of the center pixel of block and do some operations.
I don't know where to start. Using command like blockproc wont help. Can anyone suggest a start point?
5 Comments
Aparna RAJAWAT
on 5 Aug 2016
I want to divide an image into different block size.and image size is 16x16.block size are 4x4,5x5 and so on.please help me how to do coding in matlab
Answers (2)
Yaw
on 17 Feb 2011
The best way to do this is to use the "mat2cell" command. It's very simple.
- a=3; b=3; %window size
- x=size(f,1)/a; y=size(f,2)/b; %f is the original image
- m=a*ones(1,x); n=b*ones(1,y);
- I=mat2cell(f,m,n);
1 Comment
Walter Roberson
on 17 Feb 2011
blockproc() is able to handle situations where the original matrix does not happen to have dimensions that are multiples of 3. Your code will crash on those cases.
Vieniava
on 14 Feb 2011
Suppose I is your image matrix. Trivial way is shown below:
s=size(I);
wing=1; % ;)
bs=2*wing+1; % block size
for i=wing: bs : (s(1)-wing)
for j=wing : bs : (s(2)-wing)
BLOCK=I( (i-wing):(i+wing) , (j-wing):(j+wing) );
%
% paste your function/code which processes the BLOCK
%
end
end
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