How to divide 256X256 matrix into sixteen 16X16 blocks?

I am having pixel value of an image as 256X256 matrix. I want to divide it into sixteen 16X16 matrix (ie)an image into sub blocks. It is needed to compare each 16X16 with other. Can anyone help?

[Roger Stafford]

By my arithmetic, if you divide a 256x256 matrix into separate 16x16 blocks, there should be 256 of these blocks, not 16.

Answer 1

[David Sanchez]

You need to use mat2cell:

X = reshape(1:20,5,4)'
C = mat2cell(X, [2 2], [3 2])
celldisp(C)

This code returns

X =
     1     2     3     4     5
     6     7     8     9    10
    11    12    13    14    15
    16    17    18    19    20

C = 
    [2x3 double]    [2x2 double]
    [2x3 double]    [2x2 double]

C{1,1} =
     1     2     3
     6     7     8

C{2,1} =
    11    12    13
    16    17    18

C{1,2} =
     4     5
     9    10

C{2,2} =
    14    15
    19    2

In your case:

A = rand(256); % your matrix here
N = 16*ones(1,16);
B = mat2cell(A,N,N);

Answer 2

[Malarvizhi]

Can you help me to find the Sum of absolute difference for two matrices?

[MAMATHA YADAVALLI]

can anyone tell me how to divide 90*90 matrix into 729 3*3 sub matrices?

Answer 3

[Namwon Kim]

Try this answer.

x = zeros(256,256) % Input is (256,256).

a  = size(x, 1);
b  = size(x, 2);
numParts = 16

c = floor(a/numParts);
d = rem(a, numParts);
partition_a = ones(1, numParts)*c;
partition_a(1:d) = partition_a(1:d)+1;

e = floor(b/numParts);
f = rem(b, numParts);
partition_b = ones(1, numParts)*e;
partition_b(1:f) = partition_b(1:f)+1;

% Split matrix rows into partition, storing result in a cell array
% 256X256 matrix into sixteen 16X16 blocks
output = mat2cell(x, partition_a, partition_b);

Answer 4

[AMEN BARGEES]

x=your input marrix

ans= reshape(x,16,16,[]);