Re: [Lcms-user] Scanner calibration

[<ma...@li...>]

Hi,

Let me see if I understand the problem....

You have an IT/8 target, then you scan this target and
got a image in RGB. Ok right now. Then,  the IT/8 sheet
has Lab values for patches ... and you want to
generate a icc profile that characterizes the translation from
your RGB values to Lab values. Is this? So, this is just what
profiler is doing. You give to the profiler the RGB scanned
image, the IT/8 reference sheet and the profiler resturn to you
the icc profile.

The full process of obtaining a profile from a set of patches is
very complex. I can outline an algorithm for doing so, but
there is a lot of math/color science involved... I guess is not
worth of the effort required to just build one profile.

If you want to use this profile somehow embedded into scanner
firmware, you need to know in wich RGB space your scanner
is going to work. Assuming sRGB, a transform between
the obtained profile and sRGB profile will give to you the
corrected RGB values.

Martí.

----- Original Message -----
From: "Trigonix inc." <in...@tr...>
To: "Martí Maria" <ma...@li...>
Sent: Monday, June 11, 2001 3:44 PM
Subject: Re: [Lcms-user] Scanner calibration


> Hi,
> I don`t need a software to do the calibration.
> the scanner i à working on is under developement, and we have somme
probleme
> with colors :).
> So i scanned an IT8 target and compare the value (in RGB) a obtained and
the
> value given with the target.
> I know that there is a way to write a program in c++ to generate a profile
> (icc) to do some intepolation and to calibrate the scanner but HOW?
>
> thanks
>
>
> Martí Maria wrote:
>
> > Hi,
> >
> > Building profiles is still a pending subject for little cms,
> > however, KWLee has a free program that does just
> > what you ask for:
> >
> > http://www.littlecms.com/iphoto/download.htm
> >
> > The profiles generated by this tool has been tested and works
> > fine under lcms.
> >
> > Martí.
> >
> > ----- Original Message -----
> > From: "Trigonix inc." <in...@tr...>
> > To: "Martí Maria" <ma...@li...>
> > Cc: <lcm...@li...>
> > Sent: Monday, June 11, 2001 3:08 PM
> > Subject: [Lcms-user] Scanner calibration
> >
> > >
> > >
> > >
> > >
> > > Hi,
> > > how can i use the IT8 to generate an ICM profile to calibrate a
scanner
> > > that I`m working on.
> > > Thanks.
> > > Adil.
> > >
> > >
> > > _______________________________________________
> > > Lcms-user mailing list
> > > Lcm...@li...
> > > http://lists.sourceforge.net/lists/listinfo/lcms-user
> > >
> > >
>
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