Re: [APML] van Cittert Deconvolution

["Mike Unsold" <mike@mlunsold.com>]

Hi Frank,

The noise in the dark regions of your lunar image is from noise
amplification
by the Van Cittert deconvolution. This is a drawback with the Van Cittert
method.
Other methods have been devised to mitigate noise amplification. The
following
image is the result of 40 iterations of an adaptive Richardson-Lucy
deconvolution
using a 7x7 Gaussian point spread function. This method has much better
resistance
to noise amplification.

http://www.mlunsold.com/examples/Temp/PlatoCompare.jpg

Mike


----- Original Message -----
From: "Frank Barrett" <frankb@celestialwonders.com>
To: <astro-photo@seds.org>
Sent: Saturday, March 15, 2003 4:39 PM
Subject: [APML] van Cittert Deconvolution


> If this is slightly off topic, please forgive me this one indiscretion.
> There seemed to be some recent interest in deconvolution so I thought I
> would share some of my early results with this technique.  It's very
> exciting.
>
> After seeing Juan's wonderful mosaic yesterday I went home and cracked
open
> a recently acquired book "The Handbook of Astronomical Image Processing"
> which comes with the AIP4WIN software.  In it I learned of the magic of
> deconvolution and was pleased to find that the software contains the van
> Cittert algorithm.  I experimented with this on my first quarter mosaic
and
> found that it did crisp things up a bit, but if I went "too" far it seemed
> to bring out a lot of noise in the darker regions.  Anyone know how to
> mitigate this?
>
> http://celestialwonders.com/FirstQuarterMosaic.html
>
> I also took the opportunity to process a four frame mosaic of the Plato
> crater region taken at f/20.  Each individual frame is a median combine of
> 12 of the best out of 20 frames.  With this I was able to go 250
iterations
> with van Cittert deconvolution.  The results just blew me away!  It's
liked
> I've discovered a whole new dimension to this hobby!  The page contains
the
> raw convoluted image as well as the processed image for comparison.
>
> http://celestialwonders.com/Plato.html
>
> Comments welcome!
> -----
> Frank Barrett
> http://celestialwonders.com
>
>
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> Astro-Photo@seds.org
> http://seds.org/mailman/listinfo/astro-photo
>


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