Sponsor Message:
Aviation Photography Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Color Noise Reduction? Help  
User currently offlineLPHD From France, joined Aug 2013, 8 posts, RR: 0
Posted (5 months 2 weeks 3 days 12 hours ago) and read 2347 times:

Hi,

I need to reduce color noise for one of my shots to be accepted in the database.
The problem is that I've never used such a tool before. I usually use the usual noise reduction tools (with strength and detail preservation).

Do you know how to to do it? Do you how such a tool would be called in Gimp (that's the free software i'm using).
Thanks a lot in advance.

Cheers from France

6 replies: All unread, jump to last
 
User currently offlineGhajdufi From Hungary, joined Jun 2005, 234 posts, RR: 7
Reply 1, posted (5 months 2 weeks 3 days 7 hours ago) and read 2298 times:
AIRLINERS.NET CREW
PHOTO SCREENER

Salut, I personally found the built in noise reduction in adobe camera raw and lightroom very very good. There is a slider for colour noise as well as for luminosity (?) noise removal. Of course if you are using Gimp this might not help you at all but perhaps you could try a free 30 day trial just to see what the software can do for this particular image you have.
I used to use Neat Image and Noise Ninja and I was quite happy with them too.
You could also send me the original and I can see what Lightroom can do with it.
Bonne journee,
HGabor



HGabor
User currently offlineckw From UK - England, joined Aug 2010, 713 posts, RR: 16
Reply 2, posted (5 months 2 weeks 3 days 3 hours ago) and read 2278 times:

There is a way to eliminate colour noise completely, but does not affect luminosity. I don't know Gimp but in PS a quick method is to apply a Gaussian blur to the whole image - no detail should be visible (a radius of around 2 - 3 should be fine).

Next, in PS its Edit -> Fade leave at 100% but select 'color' mode.

Perhaps someone familiar with both systems can translate this into Gimp.

Cheers,

Colin



Colin K. Work, Pixstel
User currently onlinemjgbtv From United States of America, joined Jan 2008, 724 posts, RR: 0
Reply 3, posted (5 months 2 weeks 3 days 3 hours ago) and read 2275 times:

Quoting ckw (Reply 2):
Perhaps someone familiar with both systems can translate this into Gimp

It looks like the workflow and command names are pretty much the same in GIMP.

You could also use the G'MIC plugin for GIMP. It has a number of noise reduction modes for which you can select chroma noise channels.


User currently offlineLPHD From France, joined Aug 2013, 8 posts, RR: 0
Reply 4, posted (5 months 2 weeks 9 hours ago) and read 2139 times:

Hi,

Thank you very much for you help and answers. In the meantime I think I found a tool: it's called wavelet denoise. Have anyone ever heard of it?

I just uploaded my shot again to see if screeners accept it. If not, I'll get back to you.

Thanks again,
'god day


User currently onlinetopgun3 From Canada, joined Aug 2005, 263 posts, RR: 0
Reply 5, posted (5 months 1 week 1 day 1 hour ago) and read 1957 times:

I have to give a plug to DxO 9 Optics Pro. I just upgraded to it from version 7 and it has an amazing tool for de-noising any photo without loss of detail. It takes about 20x the usual length of time to process the photo (about 2-3min), but the results are worth it. The way it works is by comparing each pixel to the closest 1000 pixels to determine what colour it should be.


I'd rather be flying.
User currently offlineiamlucky13 From United States of America, joined Aug 2007, 235 posts, RR: 0
Reply 6, posted (5 months 1 week 6 hours ago) and read 1909 times:

I use wavelet denoise and am happy with it considering it's a free plugin, although I haven't compared to any of the for-pay alternatives like Noise Ninja or the function included in Lightroom.

I've not tested it exhaustively, but I seem to get the best results when performing the noise reduction in YCbCr mode, which makes sense since this isolates the chroma channels from the luminance channel. I usually make a very small adjustment in the luminance channel to soften the graininess a bit, and about twice as large of an adjustment in each chroma channel to deal more aggressively with the more distracting color noise, plus a slight softness setting to avoid pulling out too much detail. For example:
Y - Threshold 0.5, Softness 0.2
Cb - Threshold 1, Softness 0.5
Cr - Threshold 1, Softness 0.5

That will result in a relatively light-handed noise reduction. Turn them up and fiddle as you see fit. You will lose more detail the higher you turn them up.

You will want to perform sharpening and resizing AFTER you do noise reduction. Fortunately, the results produced by wavelet denoise take an unsharp mask fairly gracefully.

Quoting ckw (Reply 2):
Next, in PS its Edit -> Fade leave at 100% but select 'color' mode.

Perhaps someone familiar with both systems can translate this into Gimp.

I believe in GIMP the feature is called Layer Mode (sometimes called blending mode), accessed in the layers window. You create a duplicate layer, apply your blur to one of them, then set the layer mode to determine how they blend together. I played around with a few different modes in GIMP just now as a test, but couldn't seem to get more than minimal reduction in noise unless I accept a big loss in sharpness. Wavelet Denoise definitely works better.

Selective Gaussian Blur (which only blurs features with less than specified value difference), works much better than what I was able to get with blending, but destroys fine textures making things look plastic, especially skin texture, hair, and foliage. Maybe you can combine it with ckw's blending method and see what you get, but from the trials I've done, Wavelet is still better.

Wavelet also wins over GIMP's native "despeckle" feature for the same reasons.


Top Of Page
Forum Index

This topic is archived and can not be replied to any more.

Printer friendly format

Similar topics:More similar topics...
About Grain/noise Reduction posted Thu Jul 15 2010 09:48:28 by MHO
2nd Rejection (contrast, Noise) - Need Help posted Wed Sep 10 2008 12:15:42 by Radium15
Canon 400D In-camera Noise Reduction Qlty Issues? posted Thu Aug 28 2008 23:03:43 by Vivekman2006
Excessive Noise Reduction? posted Thu Jan 24 2008 12:25:07 by TweetDriver
Noise Reduction: Both Pre- And Post-scaling? posted Mon Aug 13 2007 19:54:46 by SNATH
Takeoff (color) Noise posted Wed Sep 27 2006 03:23:24 by Domokun
Grain/noise Reduction Question.... posted Mon Jun 5 2006 22:45:55 by Sirpug
RAW Shooter/ Noise Reduction posted Tue Mar 14 2006 15:01:05 by Dendrobatid
Strange Color....Can You Help? posted Wed Jun 22 2005 21:47:18 by SkyWestFan
Advanced Noise Reduction And Sharpening posted Tue Oct 12 2004 03:43:55 by Futterman