I know how to divide my 256x256 image into 16x16 blocks using mat2cell. Now I want to access those 16x16 blocks successively to further divide them into 4x4 blocks.

I'm able to do this further division by taking one 16x16 block at a time (first using cell2mat and then again using mat2cell this time with parameter 4), but I want to do it using some 'for' loop, or anything for that matter in which I wouldn't have to access each 16x16 blocks individually.

Any idea how I can achieve that?

Thank you.

Answer 1

[Ameer Hamza]

Read about cellfun(). Try something like this

img = rand(256);

C1 = mat2cell(img, 16*ones(16,1), 16*ones(16,1));
C2 = cellfun(@(x) mat2cell(x, 4*ones(4,1), 4*ones(4,1)), C1, 'UniformOutput', 0);

Answer 2

[Matt J]

Using mat2tiles

https://www.mathworks.com/matlabcentral/fileexchange/35085-mat2tiles-divide-array-into-equal-sized-sub-arrays

Image=rand(256);
ImageCell=mat2tiles(mat2tiles(Image,[4,4]),[4,4]);

>> ImageCell{2,3}

ans =

  4×4 cell array

    {4×4 double}    {4×4 double}    {4×4 double}    {4×4 double}
    {4×4 double}    {4×4 double}    {4×4 double}    {4×4 double}
    {4×4 double}    {4×4 double}    {4×4 double}    {4×4 double}
    {4×4 double}    {4×4 double}    {4×4 double}    {4×4 double}