

Unique
Features, Edit FFT
Edit FFT  Newspaper raster
example
Use this tool to edit the frequency
domain of the FFT with IL internal PaintBox
editor or use you favorite external paint
program. The internal editor is more
powerful in that you can directly see the
result as a preview, and finetune what you
are editing. The low frequency part of the
FFT is in the central part of the FFT image,
and the high frequency part of the FFT is in
the outskirts of the FFT image. Most of the
image information is in the central part of
the FFT image. Experiment with this tool to
learn the characteristic of the FFT.
Below is a restoration sequence in ImageLab
where an image from a newspaper is cleaned
from artifacts.
The artifacts consists of
horizontal/vertical streaks around the
center of the FFT. It's possible to remove
them by simply adding a Low Pass filer, i.e.
block the non center data of the FFT. Don't
do this to close to the FFT center however.










