On Thursday 30 March 2006 03:55 am, Graeme Gill wrote:
snip
> I'd advise making some adjustments to the spline code before doing any
> serious testing. In particular, you should ensure the following:
>
> in Argyll/rspl/scat.c line 1119, change
> double rwf[4] = { 0.1, 0.1, 0.1, 0.1 };
> to
> double rwf[4] = { 1.0, 1.0, 1.0, 1.0 };
I updated this in CVS and it will be in the next release (due in a few weeks).
>
> For the arguments to fit_rspl():
>
> Make sure that the default smoothing factor is 1.0
>
> Make sure that the default avgdev is 0.005 (0.5%)
Also up dated in CVS.
>
> (I believe the the above two are mapped to two sliders in LPROF).
My current code base (not in CVS yet) is now using spinboxes for these rather
than sliders. I will probably also remove the smoothing factor at some point
and have it always be set to 1.0.
>
> otherwise the smoothing will be too low. (These are the changes
> I've made for the V0.54 Argyll release, in light of more recent testing.)
I just ran a quick test profile and the dE numbers were slightly higher with
the updated code. The numbers were about the same as the old LPROF local
convergence extrapolation algorithm with the same target image. So the dE
numbers are still very good and presumably the curves are even smoother which
is a good thing. Thanks for the update.
snip
> > This struck me as a very good idea and I would like to pursue this. Is
> > anyone here interested in assisting with this by providing high quality
> > scans from the custom slides that Wolf is willing to produce for this
> > effort?
>
> I don't have a specialized slide scanner, but I do have an Epson 4990,
> if that is of any interest.
>
> Graeme Gill.
Wolf specifically listed Epson scanners so yes that would be helpful as long
as it can scan a slide. I think the idea is to test with a range of scanners
to see how good the profiles are for a range of hardware with a range of
profiling software. I do have a film scanner but it not a very good one and
I am sure it will have a significant amount of noise in the darker parts of
the special targets that Wolf is talking about producing for this test. It
would be useful to have some very high end (drum and Imacon) and mid level
film scanners as well.
For anyone wanting a good profile for their film scanner this is an
opportunity to get scans from hand measured targets which are normally very
expensive. So I would think people would be very interested in helping out.
Hal
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