Re: [Gimp-user] Seeking better "green screen" method

[Liam R E Quin <liam w3 org>]

On Tue, 2012-01-17 at 15:17 -0500, Jay Smith wrote:

> We have tried scanning on many different non-black background colors and 
> surfaces, but there are always some extreme-edge color artifacts 
> remaining ... leaving a sort of "halo" effect around the stamp object.

I've found that scanning object once and then rotating the object on the
scanner by 180 degrees and scanning again, and combining the image, can
help with that sort of object-depth effect. I've used it to get rid of
(or reduce) embossed lettering on old engravings for
www.fromoldbooks.org for example (also with an Epson scanner).

The reason it happens is that the scanner sensor and light have to be at
an angle to avoid reflections (including from the glass!). Television
cameras don't have this problem.

Liam

-- 
Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
Pictures from old books: http://fromoldbooks.org/