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Reverse Engineering a Filter

Posted: 2011-01-30T02:15:43-07:00
by jayuhfree
My spouse, who's a painter, has asked me to create an IM filter which can reproduce the following types of effects from an arbitrary image. It's a picture taken from our Samsung cellphone camera zooming in. I've tried a number of combinations of blurring and unsharpening, but can't seem to produce the very interesting opalescent artifacts.

Image

And

Image

Thanks!

Re: Reverse Engineering a Filter

Posted: 2011-01-30T05:29:34-07:00
by jayuhfree
So far here's what I've got. It's software-based zoom, obviously, but I suspect it's zooming on a JPG-compressed copy. That explains the artifacts everywhere. At that point, I suspect it's a combination of a blur and an edge detect? Maybe with a bit of noise added? I've been running combinations of blur->noise and now I'm experimenting with higher degrees of JPG compression.

Re: Reverse Engineering a Filter

Posted: 2011-01-30T09:23:12-07:00
by NicolasRobidoux
I can't help you, but I must say it is a very attractive effect.

Have you checked GIMP plug-ins for something similar (either pre-installed or from the plugin repositorty)?

Re: Reverse Engineering a Filter

Posted: 2011-01-30T22:49:15-07:00
by anthony
I can't see the images any more -- so I have no idea.

Put the images on something like dropbox, and edit the links of your request to them.