[Digikam-users] Idea for getting in camera quality jpeg conversions... was Re: Building a better raw conversion tool for digiKam ?

[Linuxguy123]

On Wed, 2009-12-23 at 14:47 -0700, Linuxguy123 wrote:
> All the raw files seem to have some sort of embedded jpg image in them
> that is extractable via commonly available tools. (Exiftool, exiv, etc.)
> If they didn't have the embedded images, we wouldn't be able to preview
> them in digiKam.
> 
> Furthermore, it seems as though a lot of people would consider the in
> camera generated image as a good place to start when tweaking a raw
> image - if it isn't a final image itself.
> 
> It should be possible to use the embedded image to calculate all the
> image parameters to generate the jpg from the raw file such that it
> matches the embedded image.
> 
> For starters, we could generate histograms.  One could then add code to
> the converter that tweaked the raw generated image parameters until its
> histogram matched that of the image embedded in the raw file.
> 
> By doing pixel to mapped pixel comparisons between the raw file and the
> embedded file, one should also be able to generate color curves for
> doing the conversion. 

I did a lot of reading and this might work.  But generating color
profiles using an IT8.7 target and using a raw converter that supports
the use of color profiles is the ultimate answer. 

Here is some interesting reading:

http://www.freelists.org/post/argyllcms/Profiling-between-two-images

http://sourceforge.net/projects/ufraw/forums/forum/434060/topic/2376782

http://sourceforge.net/projects/ufraw/forums/forum/434060/topic/2297961

http://lprof.sourceforge.net/help/ufraw.html

I'm off to buy an IT8.7 target tomorrow.  I'll report back how I make
out.