[Digikam-devel] [Bug 116886] New: Proposal for adding a new destripe/denoise technique

[Dik Takken]

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http://bugs.kde.org/show_bug.cgi?id=116886         
           Summary: Proposal for adding a new destripe/denoise technique
           Product: digikamimageplugins
           Version: unspecified
          Platform: Gentoo Packages
        OS/Version: Linux
            Status: NEW
          Severity: wishlist
          Priority: NOR
         Component: general
        AssignedTo: digikam-devel kde org
        ReportedBy: d.h.j.takken phys uu nl


Version:            (using KDE KDE 3.4.1)
Installed from:    Gentoo Packages
OS:                Linux

I would like to propose a new plugin that is very effective for removing stripes from slide/negative/positive scans, as well as subtle de-noising without loosing detail. The technique is described here:

http://www.no-hype.com/articles/denoise.html

For example, for removing vertical-only noise (like horizontal scanner stripes) from the image, you do this in the GIMP:

1. Duplicate the image to _two_ new layers and place the duplicates on top of the original.
2. Use the 'overlay' effect on the two top layers
3. Use the Gaussian Blur (IIR) effect on the topmost layer. Typical radius is 30 pixels
4. Use the Gaussian Blur (IIR) effect on the middle layer, use a horizontal radius of 30 pixels and a vertical radius of 1.
5. Invert the colors of the middle layer
7. Merge all layers into one.
8. Repeat the process one or more times

I always use the GIMP to use this method for removing scan-stripes and noise, then I switch to DigiKam for re-focussing (amazing plugin by the way!). The results of the combination of destripe/denoise in GIMP and re-focus in DigiKam are really impressive. 

It would be very nice to implement this manual destripe/denoise method in a DigiKam image editor plugin. Then I can denoise my pictures entirely using DigiKam.