Re: [Gimp-print-devel] Article: adaptive methods for dithering color images

[Hrafnkell E. <he...@kv...>]

On Wed, Apr 26, 2000 at 04:15:21PM +0200, Thomas Tonino wrote:
> Actually, it is not lowpass filtering, but it is determining how far the
> noise propagates. There is a thing called a 'Riemersma dither' that uses

Yes. What I meant is that there is a lowpass effect in it 
(although not 100% in the sense of linear filters). I probably should
never have mentioned it, its just the way I was thinkng about it when
I wrote my reply.

> An extension of that model would be something that actually knows about
> printer and observer capabilities, calculates the value of what has been
> produced so far, and bases a decision on that. That could be in the form

Ok, I'll admit, I've been searching for articles that might be interesting
for the project and that might teach me something about dithering methods :)
I've found two that describe model based dithering (based on a printer 
model and a perception model):

Thrasyvoulos N. Pappas and David L. Neuhoff: 
"Least-Squares Model-Based Halftoning"
IEEE Transactions on image processing, vol 8, no 8. august 1997

Thrasyvoulos N. Pappas:
"Model-Based Halftoning of Color Images"
IEEE Transactions on image processing, vol 6, no 7, july 1999

The model based methods are very interesting. They exploit characteristics
of the human visual system to get the best possible dithering.
They also compensate for dot overlap and such things (and use it to
get even better results).

I might have found even more articles but the printouts are not on
the surface of the pile of papers on my desk so I can't see them now :)

There is also an interesting book:
http://www.spie.org/web/abstracts/oepress/MS154.html
it includes the original paper by Floyd and Steinberg among other things.

-- 
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