[FFmpeg-devel] [PATCH 2/2] libavfilter/vf_colorconstancy.c : Adding weighted greyedge
Yatendra Singh
yatendra1999luffy at gmail.com
Tue Jun 30 18:30:37 EEST 2020
>
> > + s->difford = 1;
>
> Why are you forcing this value?
>
The algorithm only uses first order differentials for the calculation of
the specular variant and it does not seem to be an option to use other
orders as far as I have understood from the paper and the official code.
>
> If you are setting initial estimation to normal white, does it make any
> difference to do a chromatic adaptation?
>
I was trying to reproduce the same values as the official code in matlab
and hence this was done.
It might provide a very minor improvement in speed but having an estimate
beforehand might help converge faster.
I would update the next patch with chromatic adaptation.
>
> > +
> > +static const AVOption weighted_greyedge_options[] = {
> > + { "minknorm", "set Minkowski norm", OFFSET(minknorm),
> AV_OPT_TYPE_INT, {.i64=1}, 0, 20, FLAGS },
> > + { "sigma", "set sigma", OFFSET(sigma),
> AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.0, 1024.0, FLAGS },
> > + { "min_err", "set minimum angular error", OFFSET(min_err),
> AV_OPT_TYPE_DOUBLE, {.dbl=0.1}, 0.02, M_PI, FLAGS },
> > + { "max_iters", "set the maximum iterations", OFFSET(max_iters),
> AV_OPT_TYPE_INT, {.i64=10}, 1, 100, FLAGS },
> > + { "kappa", "set the kappa for weights", OFFSET(kappa),
> AV_OPT_TYPE_INT, {.i64=10}, 1, 25, FLAGS },
>
> Why 25?
>
Honestly, I have no idea as to what the actual upper limit on the power of
weights should be, so I used a random upper limit while testing.
What would you suggest I should use?
I would also update the new patch with all the rest of the changes.
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