Hi,
Basically, it assumes that one can generate an accurate color profile for
a digital camera, and then turn around and use it as a colorimeter to
profile your monitor.
I tried something similar long time ago, but didn't work at all.
The reasons were several, but mostly the error you get by using
a camera is too big to get suitable profiles.
My work was largely based on CRT, and may not be valid for TFT
since thet are basically differnt beasts, but here are some ideas:
- An ICC profile for CRT monitor can be built using just
matrix-shaper.
- Average error of matrix-shaper can be really low, sometimes
under < 1dE. Again, that's for CRT only
- Gamma-gain-offset model works great if you can add an offset to
refresent black point.
- Primaries mismatch is not so important, what makes a difference
(to the eye) is white point and transfer curves.
Putting all together, you can do a reasonable ICC profile for a CRT
monitor by knowing white point, primary chromaticities and transfer
curves. Primaries are on most CRT very close to Rec709 (sRGB)
so you have to know transfer function (aka gamma) and white point.
The missing part is how to characterize white point and transfer
curves without expensive hardware. I don't know either :-)
There has been some work on that. See for example HP's MIND
http://www.hpl.hp.com/techreports/1999/HPL-1999-158.pdf
But AFAIK there is still no clean solution.
Regards
Marti Maria
The littleCMS project
http://www.littlecms.com
----- Original Message -----
From: "Cory Papenfuss" <[EMAIL PROTECTED]>
To: <lcms-user@lists.sourceforge.net>
Sent: Saturday, March 04, 2006 3:48 PM
Subject: [Lcms-user] How feasible is this procedure?
I got off on the monitor profiling tangent a bit this morning, and as far
as I can tell, nobody gives a crap about linux-land monitor colorimetry.
Argyll allegedly supports two devices, but they're both old and expensive.
Ran across this idea:
http://wiki.scribus.net/index.php/Proposal_for_Monitor_Profiling
Basically, it assumes that one can generate an accurate color profile for
a digital camera, and then turn around and use it as a colorimeter to
profile your monitor.
Does this seem like a reasonable thing to do? I'm sure it's not as
accurate as a puck-like object stuck directly on the screen, but with
minimal ambient light it may be reasonable. The gamut of DSLRs in
particular is comparable to CRT's, no?
Intriguing...
-Cory
--
*************************************************************************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
*************************************************************************
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