Better results by compromise

By compromise, we can choose some pixels to do the reordering when the intensity reduced and others will not change the order during the whole process. It means we try to avoid the clumping where there is a brighter area since we think the clumping at the edges (assumed there are darkness) won't have much artefacts.

reordering when the original intensity greater than 150reordering when the original intensity greater than 100
reordering when the reduced intensity greater than 150
reordering when the reduced intensity greater than 200