This script sharpens an image with the built-in GIMP plugins erode and dilate.
These two plugins infiltrate the image with the lowest/highest pixel of the closer environment, but never higher or lower.http://docs.gimp.org/en/plug-in-dilate.htmlhttp://docs.gimp.org/en/plug-in-erode.html
This means, they can be used to sharpen an image w/out halos.
EAW Sharpen is a filter which sharpens an image without annoying halos.
It's based on Mikes Python plugin:http://www.mm-log.com/blog/2010-04-05/gimp-edge-avoiding-wavelets
More info about the algorithm from Raanan Fattal:http://www.cs.huji.ac.il/~raananf/projects/eaw/index.html