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Noise reduction

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Noise reduction Steve Crane 26 Sep 21:31
  Noise reduction Jonathan Bartlett 26 Sep 22:16
   Noise reduction Steve Crane 26 Sep 22:28
  Noise reduction Guillermo S. Romero / Familia Romero 26 Sep 22:34
  Noise reduction Jakub Steiner 27 Sep 03:25
  Noise reduction Daniel Rogers 27 Sep 04:01
Noise reduction David Hodson 27 Sep 08:17
3F74D53A.9040906@phaseveloc... 07 Oct 20:15
  Noise reduction Steve Crane 27 Sep 12:49
   Noise reduction Henrik Brix Andersen 27 Sep 14:10
   Noise reduction Daniel Rogers 27 Sep 21:11
Steve Crane
2003-09-26 21:31:40 UTC (over 21 years ago)

Noise reduction

Hi,

Are there any built-in functions or scripts for the GIMP that can be used to remove or reduce noise in digital photographs? Does anyone have a set of steps to follow to remove noise? There are several stand-alone programs available for Windows that do this but I haven't found any for Linux yet. Anyone know of any?

Thanks.

Jonathan Bartlett
2003-09-26 22:16:09 UTC (over 21 years ago)

Noise reduction

Are there any built-in functions or scripts for the GIMP that can be used to remove or reduce noise in digital photographs? Does anyone have a set of steps to follow to remove noise? There are several stand-alone programs available for Windows that do this but I haven't found any for Linux yet. Anyone know of any?

Try blurring the R, G, and B channels separately.

Go into layers->channels, de-select all but one channel, and then run your blur. Do that on each channel.

Jon

Steve Crane
2003-09-26 22:28:42 UTC (over 21 years ago)

Noise reduction

On Fri, Sep 26, 2003 at 01:16:09PM -0700, Jonathan Bartlett wrote:

Try blurring the R, G, and B channels separately.

Go into layers->channels, de-select all but one channel, and then run your blur. Do that on each channel.

Thanks. I'll play with that a bit.

Guillermo S. Romero / Familia Romero
2003-09-26 22:34:12 UTC (over 21 years ago)

Noise reduction

sjc@cidev.com (2003-09-26 at 2131.40 +0200):

Are there any built-in functions or scripts for the GIMP that can be used to remove or reduce noise in digital photographs? Does anyone have a set of steps to follow to remove noise? There are several stand-alone programs available for Windows that do this but I haven't found any for Linux yet. Anyone know of any?

http://cs.uhh.hawaii.edu/~jeschke/photography/articles/gimp/ReducingCCDNoise/ No scripts, but nice tutorials there.

GSR

Jakub Steiner
2003-09-27 03:25:11 UTC (over 21 years ago)

Noise reduction

On Fri, 2003-09-26 at 21:31, Steve Crane wrote:

Hi,

Are there any built-in functions or scripts for the GIMP that can be used to remove or reduce noise in digital photographs? Does anyone have a set of steps to follow to remove noise? There are several stand-alone programs available for Windows that do this but I haven't found any for Linux yet. Anyone know of any?

If used with caution, selective gaussian blur is great when fighting noise.

cheers

Daniel Rogers
2003-09-27 04:01:43 UTC (over 21 years ago)

Noise reduction

Steve Crane wrote:

> Hi,
>
> Are there any built-in functions or scripts for the GIMP that can be > used to remove or reduce noise in digital photographs? Does anyone have > a set of steps to follow to remove noise? There are several stand-alone > programs available for Windows that do this but I haven't found any for > Linux yet. Anyone know of any?
>
> Thanks.

It depends on what kind of noise you are looking at. Can you describe the noise more
precisely? Is it "salt and pepper" noise? Gaussian noise? If you can show an example
image I can help you pick a filter.

If you just want to use a sledgehammer, you can just use a blur filter, which will reduce
many kinds of noise, though you can almost always do better.

-- Dan

David Hodson
2003-09-27 08:17:44 UTC (over 21 years ago)

Noise reduction

Steve Crane wrote:

> Are there any built-in functions or scripts for the GIMP that can be > used to remove or reduce noise in digital photographs?

Try http://members.ozemail.com.au/~hodsond/degrain.html

Steve Crane
2003-09-27 12:49:50 UTC (over 21 years ago)

Noise reduction

On Fri, Sep 26, 2003 at 05:09:30PM -0700, Daniel Rogers wrote:

It depends on what kind of noise you are looking at. Can you describe the noise more precisely? Is it "salt and pepper" noise? Gaussian noise? If you can show an example image I can help you pick a filter.

I'm not sure I know how to describe it. I was really just asking in general terms although there is a specific image that prompted my question. Take a look at my web site at http://craniac.afraid.org and look at the very first photo there, the one with the red buildings. I used the curves on the sky section to give a similar effect to using a polarising filter. This has accentuated noise that isn't too noticeable in this small, low-res version but is quite noticeable in the full-sized original and would probably be noticeable on a print. As this is a reasonable flat area of colour the Gaussian blur filter could work but might not be the best thing to use for other images.

I think that what I'm looking for is some ideas/tutorials on different techniques that would suit different cases. I don't much care for a script that is more generic. After all if I wanted the canned approach I could just use Windows and Photoshop with it's million and three filters. I prefer to understand why the technique works as this will aid me in applying it to future, slightly different cases.

Henrik Brix Andersen
2003-09-27 14:10:40 UTC (over 21 years ago)

Noise reduction

On Sat, 2003-09-27 at 12:49, Steve Crane wrote:

I think that what I'm looking for is some ideas/tutorials on different techniques that would suit different cases. I don't much care for a script that is more generic. After all if I wanted the canned approach I could just use Windows and Photoshop with it's million and three filters. I prefer to understand why the technique works as this will aid me in applying it to future, slightly different cases.

http://mmmaybe.gimp.org/tutorials/#Photo has a few tutorials describing how to remove noise from photographs...

Sincerely, ./Brix

Daniel Rogers
2003-09-27 21:11:13 UTC (over 21 years ago)

Noise reduction

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Steve Crane wrote:
| I think that what I'm looking for is some ideas/tutorials on different | techniques that would suit different cases. I don't much care for a | script that is more generic. After all if I wanted the canned approach | I could just use Windows and Photoshop with it's million and three | filters. I prefer to understand why the technique works as this will | aid me in applying it to future, slightly different cases.

Well, if you want to know how/why a filter works, the best source I can offer is Gonzalez and Woods, Digital Image Processing (2nd Edition). It is expensive and very mathamatical, but is one of the best introductions to image processing, with a large part devoted to noise reduction techniques.

here is an amazon link: http://www.amazon.com/exec/obidos/ASIN/0201180758/qid=1064690090/sr=2-1/ref=sr_2_1/002-0655961-8698467

- -- Daniel
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