How to split a matrix in "submatrices"?

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Francesco Boari
Francesco Boari 2017년 12월 12일
댓글: Francesco Boari 2017년 12월 13일
How can i divide a matrix into submatrices of given dimensions in automatic way?
example:
data=reshape(1:88,11,8); %create a matrix
[mpixel,npixel]=size(data); %matrix's dimensions
m=2; %rows of the submatrix
n=3; %columns of the submatrix
v_w=floor(mpixel/m); %number of "vertical" submatrices
h_w=floor(npixel/n); %number of "horizontal" submatrices
cropdata=data(1:v_w*m,1:h_w*n);%crop matrix that can be diveded using that mxn submatrices
%
newdata=mat2cell(cropdata,[m m m m m],[n n]);
This code work but if I have bigger matrix I must continue to explicit [m m m...],[n n n...] in the last command and it's crazy. How can i use the command mat2cell with a smarter way?
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Image Analyst
Image Analyst 2017년 12월 12일
Why not just use blockproc() and let that handle the getting of the submatrices?
Francesco Boari
Francesco Boari 2017년 12월 13일
I see the documentation of blockproc(), it processes block by block but at the end the output it's the input image/matrix.

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Guillaume
Guillaume 2017년 12월 13일
As others have said, there may be no need to explicitly split the matrix, but if you must what is wrong with:
newdata = mat2cell(cropdata, repelem(m, v_w), repelem(n, h_w));
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Francesco Boari
Francesco Boari 2017년 12월 13일
Thanks! It works. Meanwhile i have found a different way leaving, as someone said, the original matrix and indexing.

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