From: Alan Friedman <alan@greatarrow.com>

Date: July 27, 2006 11:08:16 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Archimedes final and comparison

Hi Eric -

Nice work. The extra alignment points helps resolve quite a bit of additional detail on the floor of Archimedes. Something you might try (if you haven't already) is to apply some additional iterations in Photoshop CS2 of despeckle followed by unsharp mask using a tight pixel radius (.5 - .8). If you do this globally on the image you will begin to create artifact in the high contrast areas and larger craterlets. But if you use Photoshop to select just the smooth areas of the crater floor (feathering the selection by 5 or 10 pixels or so) you will draw out many other small details. The tight pixel radius for unsharp mask is helpful for creating a natural result and keeping the craterlet size in accurate proportion.

best -

Alan

On Jul 26, 2006, at 7:34 PM, Eric wrote:

Hi guys,

Well, I've extracted about as much detail as I'm going to for this composite. I have posted comparison images. On the left, is the original 415 stacked images composite using 5 alignment points. The right image is the same number of stacked images (415), but alignment points were increased to 17. If you look carefully, there is definite improvement, although mostly subtle:

http://www.mindspring.com/%7Eastro4565/Archimedescomparison.jpg

I was never able to improve the interior craters because the contrast wasn't enough to cause the software to align on for a stack. I also ended up using a Win program called Iris to do the 17 points, although the initial image on the left was aligned in IIDC. I think the lack of contrast and noise levels caused IIDC to eliminate about half of the stacked frames.

Eric

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