Milton Taylor wrote:
The parameter controls the trade-off between smoothness and fitting accuracy.Hi Graeme,
I'm interested in finding out more about the -r option. I'm remaking my film scanner profile, and this switch seems to have quite a dramatic effect on the results.
Leaving it off, i.e. default value, gives the best results in terms of avg and peak dE. Going from -r 0.5 to -r 0.75 and the error doubles. At -r 1.0 it's even worse.This depends mostly on your particular device and your particular measurements. If your device and your measurements were perfectly noise-free and perfectly accurate, and if the reproducibility of your device would be perfect, then indeed rather a low r (resulting in a low dE fitting error) would be desired.
You indicated that the default was too low, so why select a higher -r value if it gives a profile that is apparently not as good?
Just for info, in my case, -qh gave these results: r = 0.25 avg dE=0.38 peak 2.8 r = 0.50 avg dE=0.48 peak 3.7 r = 0.75 avg dE=1.0 peak 7.8 r = 1.0 avg dE=1.6 peak 9.5
Which is the 'right' value of -r to use?
Regards, Gerhard
Cheers, Milt