Bug 179413 - Support restoring blown out highlights
Summary: Support restoring blown out highlights
Status: RESOLVED FIXED
Alias: None
Product: digikam
Classification: Applications
Component: Plugin-RawImport-Native (show other bugs)
Version: 0.9.4
Platform: Gentoo Packages Linux
: NOR wishlist
Target Milestone: ---
Assignee: Digikam Developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2009-01-02 21:18 UTC by Dik Takken
Modified: 2022-01-26 04:23 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In: 0.9.5
Sentry Crash Report:


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Description Dik Takken 2009-01-02 21:18:10 UTC
Version:           0.9.4 (using KDE 3.5.10)
OS:                Linux
Installed from:    Gentoo Packages

DigiKam could use a function that allows the user to restore the highlights of the image. Restoring hightlights is needed for all pixels that have at least one clipped channel. UFRaw suports this.

More info about how UFRaw does this:

http://people.zoy.org/~cyril/dcraw_lchblend/highlight_recovery_dcraw_lch_patch.html
Comment 1 caulier.gilles 2009-01-03 10:18:14 UTC
Already implemented in digiKam 0.9.5 with libkdcraw based on libraw (try last version 0.1.7). Use RAW Import tool for details.

It's the same with KDE4 version. 

Look this screenshot for details:

http://www.flickr.com/photos/digikam/3162004701/sizes/o/in/pool-817639@N22/

Gilles Caulier
Comment 2 Dik Takken 2009-01-03 12:42:27 UTC
I forgot to mention that I would like to have this available for all image formats, not only RAW images. Reopen?
Comment 3 caulier.gilles 2009-01-03 12:49:53 UTC
Well, i think no,

...because, it's only possible with RAW, before to do all post processing adjustement. Why ? because information is lost especially with highlight.

This is the advantage of RAW and 16 bits color depth.

Gilles Caulier
Comment 4 Dik Takken 2009-01-03 13:05:54 UTC
Hmm... Well, I never tried it on 8-bit JPEG images but I can't think of any technical reason why it shouldn't work.. The technique is targetted at pixels that have one or two channels clipped. This problem exists in many images, not only  RAW images. That is why I think it would be a good thing to allow the user to apply highlight restoration to any image.

Another reason why DigiKam should do highlight restoration on any image: When the user processes images in DigiKam, pixel values can clip without the user noticing it. Sure, DigiKam can show clipped pixels in the image. But DigiKam only shows pixels that have all three channels clipped. Pixels with only one channel clipped do not show up. Because DigiKam can easily clip pixels without warning, there should be a means to fix the damage caused by image processing.

One more thing: There are more 16-bit image formats besides RAW images. Think of TIFF files. Currently, DigiKam does not allow the user to restore the highlights of these files.
Comment 5 Mikolaj Machowski 2009-01-03 14:41:41 UTC
This is similar in nature for Highligh/Shadows feature known from Adobe PS but also present in programs like RawTherapee.