Friday, January 25, 2013

Sharpening Moon with deconvolution

I bought a Barlow 2x lens for my Skyliner 200 and immediately went out to test it. I actually got quite lucky to have a clear sky that night. I took some photos of Jupiter and Moon and shared them on IRC. A friend suggested I should sharpen the photo of Moon with something like this:

Having studied physics, I'm familiar with the concept of convolution and I'm aware it should be possible in theory to reverse the process. Still the images on that page seems like magic to me. The software Astra Image seems like a nice program but of course it has a price. I'm not against commercial software and the price isn't too high, but I always try to look for an open source alternative to everything.

I found Grey's Magic Image Converter. It even has a plugin for Gimp. Better yet, it installs right from Portage on Gentoo. There are .debs on their page so probably installation is easy also on Debian based distros such as Ubuntu.

I didn't try the command line version yet, only the Gimp plugin. Some page I found (and lost again so no link) suggested on command line you get better results than plugin. Perhaps there are more parameters to set or something. I'll try that later, but now the Gimp plugin.

I took some photos of the Moon. With my new barlow, I can fit about one fourth of the Moon in one picture. I made a panorama of six photos with Hugin. Because of my haste to get something ready, the images were jpegs from the camera. That's why the dark grey circle around the Moon. I probably should do some editing for the raw photos before stitching the panorama.

The photo is huge. Here's a part of it:

And here is the same photo deconvoluted:

See the difference? I applied (in haste as usually) G'MICs deconvolution filter with almost the default settings and that's what I got. Btw it took quite a while for 4200x4300 image.

Here are the original and deconvoluted photos:

Left one is the original and right one deconvoluted.
EDIT: Looks like Google doesn't show the photos in their original size. I'll add them elsewhere and link here.

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