Re: 20030725 NOAA0652 sunspo

From: John Moore (xxxxx_at_none.net)
Date: 07/25/04 

Date: Sun, 25 Jul 2004 17:33:16 GMT

"Eric Ng" <ericng@cuhk.edu.hk> wrote in message
news:ce0no1$m6j2@imsp212.netvigator.com...
> Hi John,
>
> Thanks for your comment. I seldom use Maximum Entropy for my webcam image.
> Those images were processed with mild wavelet processing in Registax and
> unsharp masking in photoshop. As the webcam I used is a BW CCD in RAW
mode,
> the noise is very minimal.
>
> Just curious why you think those "noise" you think was caused by Maximum
> Entropy? Actually any sharpening filter can enhance the visibility of the
> noise. That is very kind of you if you could highlight the noise on my
> image, I will try using another processing approach and see whether it can
> be improved.

Hi Eric,

The noise appears as extra bright, white regions either over the granulation
or in the penumbra. To see what I'm talking about, try applying the dust
and scratches filter in Photoshop. Don't adjust the settings too high as
otherwise the image will become too smooth, but I think you see a difference
between just granulation and granulation mixed with noise. I see the noise
in many of the recent images, especially where Max Entropy was applied but I
can see now where you didn't use it. The sun is a tough one because it's
hard to distinguish the noise from the granulation. Don't get me wrong-
that's a very nice image with less noise than most, but I can see just a
small amount of it. Probably not worth the effort because the details more
than make up for it.

John

> Cheers,
>
> Eric Ng
>
>
> "John Moore" <xxxxx@none.net> ¦b¶l¥ó
> news:A7RMc.13817$f4.8447@newsread3.news.atl.earthlink.net ¤¤¼¶¼g...
> > These aren't too bad, Eric, although if you're using maximum entropy for
> > enhancement, you have to be careful not to intoduce excessive noise
along
> > with the granulation. Did you use max ent here? Just wondering,
because
> I
> > see a bit of noise.
> >
> > John Moore
> >
> > "Eric Ng" <ericng@cuhk.edu.hk> wrote in message
> > news:ce0lfo$m6f1@imsp212.netvigator.com...
> > > Dear friends,
> > >
> > > Attached was the NOAA0652 sunspot group captured on 25 July, 2004 with
> 4"
> > > APO refractor and BW ToUCam Pro at F20 and F40 respectively.
> > >
> > > Wish you like it.
> > >
> > > http://www.ort.cuhk.edu.hk/ericng/20040725-NOAA0652-closeup.jpg
> > >
> > > http://www.ort.cuhk.edu.hk/ericng/20040725-NOAA0652.jpg
> > >
> > > Regards,
> > >
> > > Eric
> > >
> > >
> >
> >
>
>

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