Matlab: How to combine blocks back to original matrix?

Question

So I calculated the inverse dct of smaller blocks of 8x8. I need to combine them all into a matrix. How can I combine them? This is my intermediate code. Upon each iteration, i-dct of a block is calculated and stored in idctBlock.

for row=1:8
   for col=1:8
       chunk = X{row,col};
       dctCalculates = idct2(block)
       
    end
end

Any help please?

Answer 1

You can preallocate the matrix and insert the blocks into the right position:

matrix = zeros(144, 176);
for row=1:8
   for col=1:8
       block = X{row,col};
       idctBlock = idct2(block)
       matrix(8 * (row - 1) + (1:8), 8 * (col - 1) + (1:8)) = idctBlock;
    end
end