AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2010.05.23 14:03 "[Tiff] How to descreen bilevel TIFFs into grayscale?", by Oliver Geisen
2010.05.23 21:38 "Re: [Tiff] How to descreen bilevel TIFFs into grayscale?", by Olivier Paquet

2010.05.23 21:38 "Re: [Tiff] How to descreen bilevel TIFFs into grayscale?", by Olivier Paquet

2010/5/23 Oliver Geisen <oliver.geisen@kreisbote.de>:

i have bilevel TIFFs in high resolution. The contain screeningpatterns which represents gray level, just like you look at printed pictures with a magnifier glass.

Now i want to calc previews from that. I tried to median the bits, but it still has artefacts on it. Is there a tool/way to descreen the rastered data to get better results?

Maybe I'm missing something but since your output is grayscale, it should be as simple as resizing the image in gimp or some similar tool. That resizing involves a filtering kernel to compute one low resolution pixel from several high resolution pixels. The most basic one would be to average the pixels together. This is often called a box filter.

Olivier