3 ms·
Well, I did say experimenting, didn't I? I found the thing which inspired my space filling curve exploration: https://www.compuphase.com/riemer.htm https://www
by microcolonel 9y ago
Well, I did say experimenting, didn't I?
I found the thing which inspired my space filling curve exploration: https://www.compuphase.com/riemer.htm https://www.compuphase.com/riemer.htm
The Butteraugli score between the standard lena and the Riemersma dither is about 0.5 better than the standard Floyd-Steinberg one.
Approaches like this come closer to back-propagation of errors, the lack of which is where some of the artifacts of unidirectional dither come from. In practice, any decent (full bleed) error diffusion dither works perfectly fine going between 16 and 8 bit planes, but why shouldn't I try some things out which (as you are quick to point out) may have very little value.
Heck, even gamma correction isn't strictly necessary when you're going from 16 to 8 bit sRGB.
- mark-r 9y agoYes, once you start working on a very small segment of the curve it's close enough to linear and gamma correction becomes overkill.
- jacobolus 9y agoI could see it making a difference in average color of very noisy regions, especially brightly colored ones. I suspect you could deliberately construct an image where the difference could be seen by human observers.
- jacobolus 9y agoI don’t know enough about Butteraugli (in particular in the range of very very tiny differences in the image) to know whether it’s a reasonable metric for comparing dithering algorithms. Why do you think this Riemersma method does better at that metric? Maybe it just keeps the diffused errors spatially closer to the original pixel?