From: "Tim" <tjp314@pacbell.net>

Date: September 26, 2005 2:20:33 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: processing comparison

Alan:

Sounds similar to work I did on "super resolution" of Viking Orbiter images of the Mars 

Pathfinder landing site during our site selection process.  We had 40m/pixel images that 

had been taken of the region during the Viking mission when they had hoped to land VL-1 

there.  I was able to get about a 2-fold increase in resolution (and a bigger improvement 

in signal/noise) because we had 4 or 5 of these images overlap where Pathfinder landed.  

The way I did it then, and applied later to processing video of Jupiter (captured with a Sony 

8mm camcorder and grabbed with a Video Spigot board in a Mac IIvx!) was to individually 

rescale the images so they all registered with the base image.  

Yep, this takes a lot of time.  And so I'm hopeful that someday we can select multiple 

features on a planetary disk and have the software not only align and stack the frames, but 

scale them to match as well (even if it means different scale factors for each image).  

These days, I'm looking more for a "KISS-rule" method of acquiring and processing my 

images.  If it takes hours to produce a single frame, I'm afraid I won't produce a single 

frame!  ;oD

-Tim.

--- In Astro_IIDC@yahoogroups.com, Alan Friedman <alan@g...> wrote:

Hi all -

You might have heard me ramble on about the benefits of using multiple 

alignment points for stacking in astro images. I thought I would upload 

a comparison image for you to look at.

http://groups.yahoo.com/group/Astro_IIDC/files/Lunar/tycho.proc.comp.jpg

This image of Tycho was taken in fair (5/5 pickering) seeing at the end 

of August. I was able to select 214 decent frames from a total of about 

1100 for stacking. The right hand image shows the results of a single 

stack using the central mountain peaks for registration of the images. 

The left hand image was created using data from 30 different stacks 

applied into the right image. In this was, the image is "focused" on 

different regions gaining a modest but noticeable improvement. The 

improvement is most easily seen as you move away from the center of the 

image in these reduced images.

Here is a summary of the technique.  In the stacking software, multiple 

stacks are created from the same frame selection and are saved 

separately. In photoshop, a base layer is created from the original 

mountain stack and then new layers are created for the focus regions. 

Each focus file is opened, a selection is created around the focus for 

that image, the selection is feathered, copied and then pasted into a 

layer over the base layer. Once they are registered over the master and 

flattened, final processing is done and the image completed.

I like to think of this as adaptive optics for the Great Lakes. You can 

see the final image here:

http://www.geocities.com/alanfgag/tycho.jpg

Obviously the technique is time consuming and the improvement is 

subtle. It is of most advantage in lunar and solar imaging but will 

offer improvements in planetary imaging if you work at a large image 

scale (long EFL). It is not an option currently with stacking in Astro 

IIDC, but may be down the road so I thought I would share it here.

best,

Alan