[sane-devel] CIS scanners: to calibrate or not to calibrate :) this is the question (my scanner is mad and lazy :)

[litlle girl]

2008/6/28 Rene Rebe <rene at exactcode.de>:
> litlle girl wrote:
>>>
>>> The windows driver probably calibrates once, when the scanner is
>>> first used, and stores the reference data somewhere (file, registry,
>>> etc.).
>>>
>>> The SANE driver should try to do the same (not registry of course,
>>> but some /var/... whatever file-system location.
>>>
>>> Yours,
>>>
>>> --
>>>  René Rebe - ExactCODE GmbH - Europe, Germany, Berlin
>>>  http://exactcode.de | http://t2-project.org | http://rene.rebe.name
>>>
>>
>> This is very good idea! :)
>> I think "calibrate.conf" is good place to put calibrate data.
>>
>> calibrate.conf structure:
>> vendor, product, mode (Lineart,Gray,Color) calibrate data
>>
>> Maybe "recalibrate" option will be needed :)
>
> As proecssed run with normal user's ID have to be able to
> write to it some Un*x a-like /var/state/sane/$backend-$model.raw
> file should be more suitable.
>
> But as I'm not in CPU-less scanners the backend authors
> will probably figure out what they like most.
>
> Yours,
>
> --
>  René Rebe - ExactCODE GmbH - Europe, Germany, Berlin
>  http://exactcode.de | http://t2-project.org | http://rene.rebe.name
>

I've made some research,
I scan 3 times at lineart, gray and color mode and grep from log last
calibrated exposure_time.

Lineart
1st [gt68xx] gt68xx_generic_set_exposure_time: 0x300 0x3b3 0x40a
2nd [gt68xx] gt68xx_generic_set_exposure_time: 0x301 0x300 0x3fc
3rd [gt68xx] gt68xx_generic_set_exposure_time: 0x301 0x3b3 0x29c
Gray
1st [gt68xx] gt68xx_generic_set_exposure_time: 0x300 0x2c2 0x29c
2nd [gt68xx] gt68xx_generic_set_exposure_time: 0x341 0x3d2 0x29c
3rd [gt68xx] gt68xx_generic_set_exposure_time: 0x350 0x40b 0x44c
Color
1st [gt68xx] gt68xx_generic_set_exposure_time: 0x33b 0x2c8 0x29c
2nd [gt68xx] gt68xx_generic_set_exposure_time: 0x300 0x2c9 0x29c
3rd [gt68xx] gt68xx_generic_set_exposure_time: 0x300 0x2c7 0x29c

It doesnt make much sense :(
LLG