Re: [APML] Comet NEAT c2002 Q4

> Now heres an image in serious need of SGBNR...

Hi Chris and Rodney.

The image is indeed a perfect test for noise reduction of extremely grainy film images.

I couldn't resist the temptation to try it with our PixInsight. I started with the first raw image (www.ryderhome.com.au/ap/image1). I used à trous wavelets multiresolution analysis for small-scale noise reduction (including jpeg compression artifacts), and SGBNR in the CIE L*a*b* space for large-scale noise reduction. To remove the strong gradient (due to twilight illumination, I guess), I generated a synthetic background model and subtracted it. Then I applied a slight curves adjustment. This is a quick result:

Of course it should be furtherly improved for color balance and midtones, and probably a better noise reduction could be achieved with more care, but hope it can help as a processing guide.

Congrats Rodney for a beautiful one!

--
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Juan Conejero, Pleiades Astrophoto
juan.conejero_at_pleiades-astrophoto.com
http://pleiades-astrophoto.com/
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>
> -----Original Message-----
> From: astro-photo-bounces@seds.org
> [mailto:astro-photo-bounces@seds.org]On Behalf Of Rodney @ Ryder
> Homestead
> Sent: Tuesday, April 27, 2004 8:15 PM
> To: Discussion of Film Astrophotography
> Subject: [APML] Comet NEAT c2002 Q4
>
>
> Being in the southern hemisphere gives one the opportunity to capture some
> early images of comet NEAT c2001 Q4. It also gives me the chance to exercise
> my new Minolta Dimage Scan Dual III scanner and my scanning/processing
> skills (or lack of !!)
>
> I have uploaded three images that I would appreciated feedback on. The
> general specifications for all photos are:
> Camera = Canon F1; Lens = 135mm FL 1:2.5 @ F4
> Film = Konica Centura Super 800; Guiding = Manual
> Mount = Losmandy GM8; Camera piggybacked on C9.25" SCT
> Exposure time = 4 minutes.
>
> I have uploaded three images.
>
> Image 1 is the raw scan without any adjustments.
> www.ryderhome.com.au/ap/image1
> Image 2 has been adjusted at the scanning stage for exposure and RGB
> histogram adjustment.
> www.ryderhome.com.au/ap/image2
> Image 3 had been adjusted in photo shop for colour balance and
> brightness/contrast.
> www.ryderhome.com.au/ap/image3
>
> This is my first attempt at scanning/processing and uploading so any
> feedback and suggestions for improvement would be great.
>
> Many thanks,
> Rodney Watters

Re: [APML] Comet NEAT c2002 Q4 - noise reduction