Some results

our method
error diffusion

The orders are based on the intensities and it use the circular mask with radius 5. Based on the normalization for each mask to distribute the intensity(or called errors).

For each mask, weights using function as follows:

maxin = max(0.5,(Ii/(5*pow(r,4.0f))));

in = min(maxin, 255-Ii);

less clumping but more patterns maxin = max(0.5,(Ii/(5*pow(r,3.0f))-Ii/(50*pow(r,3.0f)));

in = min(maxin, 255-Ii);

I cannot see many improvements after correcting the boundary conditions.

maxin = max(0.5,(Ii/(5*pow(r,3.0f))));

in = min(maxin, 255-Ii);

A little bettern results than others both for clumping and for patterns. Comparing with the results from error diffusion, still more patterns and more clumping in inbetween intensities(around 100-150). maxin = max(0.5,(Ii/(5*pow(r,2.0f))));

in = min(maxin, 255-Ii);

More clumping, especially for the hats.