[argyllcms] Re: Camera profiling with bracketing

  • From: Nikolay Pokhilchenko <nikolay_po@xxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sun, 13 Mar 2011 14:22:58 +0300

Iliah, did You check the diag.tif (-dipn option) in both cases? What the 
difference is?

I've prepared custom *.cht file for my target with smaller sampling areas for 
the patches (wider spacers between them) and I have no problem with X-Rite 
Digital Color Checker SG even without a tripod. The sampling area I've choosed 
is 50% from whole area of each path, so the x/y dimensions of sampling area are 
about 29% smaller than full patch size.
Another moment: I do no crop of the target. I just wiping the rest of image 
with black, so scanin "sees" only the target and have no chance to mistaken. 
I'm using perceptual correction in scanin and suppose the cropping of image is 
not recommended in such case.
See the recognized diag image: 
http://content.foto.mail.ru/mail/nikolay_po/tech/s-1374.png

Sat, 12 Mar 2011 22:46:11 -0500 Iliah Borg wrote:

> Dear Graeme,
> 
> >> Such shots are done using tripod and remote, so if user (or scanin) samples
> one chart
> >> all other locations are the same. I prefer manual sampling (like it is done
> in RPP)
> >> because that allows to avoid any imperfections right from the start. It
> seems that
> >> profiles with manual sampling go easy to 6dE max, while with scanin they
> are usually
> >> about 12 to 20 dE.
> > 
> > I'd be interested to have a sample that shows such a difference, as scanin
> > should work better than that.
> 
> From manual sampling using RPP:
> 
> STDEV_R       STDEV_G STDEV_B
> 0.36  0.31    0.32
> 0.34  0.22    0.27
> 0.36  0.24    0.27
> 0.38  0.28    0.27
> 0.41  0.23    0.24
> 0.38  0.2     0.24
> 0.33  0.26    0.29
> 0.36  0.26    0.26
> 0.34  0.28    0.3
> 0.39  0.28    0.37
> 0.39  0.2     0.28
> 0.32  0.22    0.31
> 0.44  0.32    0.35
> 0.42  0.23    0.28
> 0.38  0.29    0.3
> 0.32  0.2     0.31
> 0.35  0.27    0.27
> 0.38  0.23    0.25
> 0.26  0.18    0.2
> 0.29  0.17    0.2
> 0.35  0.22    0.25
> 0.35  0.26    0.3
> 0.42  0.29    0.32
> 0.48  0.33    0.3
> 
> 
> Sampling with scanin
> 
> STDEV_R       STDEV_G STDEV_B
> 0.58  0.64    0.66
> 0.56  0.59    0.61
> 0.62  0.61    0.59
> 0.62  0.61    0.7
> 0.62  0.6     0.56
> 0.63  0.56    0.58
> 0.54  0.59    0.7
> 0.64  0.6     0.55
> 0.53  0.59    0.57
> 0.6   0.6     0.59
> 0.59  0.57    0.65
> 0.57  0.57    0.65
> 0.72  0.67    0.62
> 0.63  0.6     0.65
> 0.53  0.61    0.63
> 0.52  0.55    0.64
> 0.56  0.61    0.57
> 0.67  0.61    0.56
> 0.45  0.46    0.48
> 0.51  0.52    0.51
> 0.58  0.58    0.58
> 0.61  0.61    0.6
> 0.62  0.63    0.61
> 0.68  0.68    0.67
> 
> --
> Iliah Borg
> ib@xxxxxxxxxxx


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