A set/groups of binary masks, such as the one shown in Figure ,
are being used to remove unwanted parts of the image residue, in addition
to other alternations to the data - alternations that are intended
to give models which can be presented for meaningful variation. Had
a method for mask synthesis and data making been formally described,
it would have been a lot easier.
Looking at the same type of transformation but combined (both thresholds
and mask) from another angle, it looks something like the examples
in Figure .