A quadtree decomposition approach for surface assessment

The present study introduces a quadtree decomposition approach for assessing surface structures. The calculated quadtree variables like the number of blocks (nQT), the mean block size (mQT) and the standard deviation of the block sizes (sQT) seem to be suitable surface descriptors for quantifying the structural changes of the paper surface due to, e.g. production or printing conditions. The graphical representation of the quadtree decomposition is also intuitive and easy to interpret, thus giving a unique opportunity to observe and track structural changes locally.