ArticlesSoftware TechniquesGIMP/Imagemagick Noise Removal with Median Filter

GIMP/Imagemagick Noise Removal with Median Filter

By patdavid | Published May 7, 2013 | Software Techniques

Tagged with: gimp imagemagick noise-reduction retouching

Photoshop users have had at their disposal a method of combining layers using a mathematical median function, and now the F/OSS users can use the same method to remove noise from static images!

To illustrate, here is an image of mine shot on my OM-D E-M5 at ISO 25,600:

1/100 second, f/8, ISO 25,600

This is a great method for reducing noise in images that are static scenes. All it requires is for the images to be properly aligned, either through a tripod, and/or using software in post.

And Imagemagick or G'MIC for GIMP.

Here are some side-by-side 100% crops to illustrate:

These results were obtained from simply median blending 10 images of the same scene. For details on how it's done, head on over and read the rest of the article:

Noise Removal in Photos with Median Stacks (G'MIC/GIMP & Imagemagick)

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Total comments: 2

Did you save in TIFF (or RAW) to avoid compression artefacts that would pollute all the similar images in a similar way?

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The technique can work with any formats you want to use (If you're looking for the best control, RAW, build a profile to apply to the image, apply to all, and output those as either TIF or PNG @ a high bit depth).

For these examples, I just used the jpg out of the camera, as it was a relative comparison as opposed to total quality (comparing a single jpg at low ISO, to a series of jpgs at high/same ISO).

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Total comments: 2