[libcamera-devel] CCM from CCT: why not mired?

[Jack Hogan]

Thanks Laurent, I look forward to hearing their thoughts.

Jack

On Sun, Jun 7, 2020 at 3:01 AM Laurent Pinchart <
laurent.pinchart at ideasonboard.com> wrote:

> Hi Jack,
>
> On Sat, Jun 06, 2020 at 04:58:00PM +0200, Jack Hogan wrote:
> > Hello,
> >
> > I am not a programmer but I was perusing the calculate_ccm module in
> ccm.ccp
> > and I noticed that the interpolation factor lambda is computed directly
> off
> > correlated color temperature values in deg K.  Normally this is done in
> mired
> > units, that is the interpolation factor is computed using one over each
> of the
> > cct's, see for instance the DNG SDK.  Is there a reason why it was not
> done
> > this way?
> >
> > Also the matrices in apply_saturation the coefficients look incorrect
> (from the
> > 601 standard instead of 709).
> >
> > Hope it helps.
>
> Thanks a lot for the feedback. I've added David and Naush in CC, as the
> authors of the code I'm sure they know better than I do :-)
>
> --
> Regards,
>
> Laurent Pinchart
>
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