[argyllcms] Re: Using two cameras to create a (pseudo) profile
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sat, 14 Jul 2012 14:57:52 +1000
Bernhard Bablok wrote:
> Hi,
>
> is the following procedure possible with the use of argyll-tools?
>
> * print a target (e.g. with targen)
> * create a cht-file for the target
> * take an image with camera A
> * create the reference-file from the image from camera A
> * take a second image with camera B
> * create a profile using the reference-file created with camera A
>
> I know this is not really the catholic way, but I want to make the
> colors of camera B look like the colors of camera A. BTW: "camera A"
> could also be a film-camera+film-scanner (even using BW-film).
Hi,
I'm not sure why you want to deviate from a normal
device space transformation. Simply profile camera A and profile
camera B, and then create an RGB to RGB space transform from
camera B to camera A device space. The transform can be on the fly
using a CMM/cctiff or application, or using a device link (collink).
ie. to be explicit, you want to emulate this:
Scene CIE -> camera A processing -> RGB of camera A
-------------- = camera A B2A ------------------
with this:
Scene CIE -> camera B processing -> RGB of camera B
-------------- = camera B B2A ------------------
So overall you want this:
Scene CIE -> camera B processing -> RGB of camera B
-------------- = camera B B2A ------------------
-> inverse camera B processing -> Scene CIE
-------------- = camera B A2B ------------------
-> camera A processing -> RGB of camera A
-------------- = camera A B2A ------------------
and camera B A2B + camera A B2A is a normal device link.
(This ignores any issues with gamut, white point etc.)
Graeme Gill.
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