Hi all,
a known effect for BIR is that the general rotation formula produces holes
on closed blocks. I found different algorithms in wikis (e.g. the
shear-algorithm (Paeth)) and the paper "Hierarchical Block Matching Method
for Fast Rotation of Binary Images" (Chien,Baek) which led me to "Parallel
image transformation and its VLSI implementation” (Cheng,Tang,Suen). I
implemented the last two algorithms and they work as expected.
They all use a real to integer mapping using floor(x+0.5) (C syntax).
Is there a method not only rotating just the integer coordinate (x,y) but
also its associated cell built by floor((x + 0.5, y + 0.5))?
I investigated this "cell" rotation (what I call incidence rotation) and
developed a mapping which improves the results of the two papers above and
want to get a feeling wether I am on the right way. My results also shows
visually rather simple, how holes are created by rotation.
Thanks in advance!
Elmar
