A comparison of using different block/overlap sizes

Here is the template texture:

The first one uses blocks of 61*61 and overlap size 20*20, while the second one is done with 15*15 blocks and 5*5 overlap regions. For this template, using a larger block is better because small blocks can not capture the structures in the texture. Also, blocks should be small enough so that the interaction between structures is left up to the algorithm. Given a block size, we always choose about one third of it to be the size of overlap region. The size of the overlap region must be large enough so that each block can agree well with its neighbors.