[sane-devel] Bypassing calibration in LiDE 110

[Stef]

On 07/22/2012 06:42 PM, Anton Marrast wrote:
> Hi,
> I've found this old message about bypassing calibration in LiDE 60
> http://lists.alioth.debian.org/pipermail/sane-devel/2008-December/023403.html
>
> I've tried to change genesys sourcecode but it's really different now 
> comparing to 2008 version.
> The thing is that i need to make my scanner work with scannerlamp off 
> (with the lens tray and transparent plastic light transmitter are 
> removed). Where should i alter genesys sourcecodes?
>
> It's actually worked pretty fine with modified LiDE 110 using 
> scanimage but last three days, all the scans become messed up with 
> extremely colouful stripes (in color mode, and grey ones in 
> grayscale). I've changed the scanning sensor of the scanner (from 
> another LiDE 110) and then compared the scans – the stripes were 
> totally identical, so it isn't the sensor.
>
>
Hello,

bypassing calibration isn't a good idea, all the pixels in a sensor 
don't give the same value given the same scanned color. So you have scan 
a well known target (usually white), and compute correction coefficients 
for each pixel based on the scanned values. These are sent to the 
genesys chip so you get good scanned data.

Since it was asked frequently, I have added an option to turn lamp off 
during scan, look at the man page. Calibration is still done with lamp 
on. Maybe it could help.

If you really don't want calibration, just add the 
GENESYS_FLAG_NO_CALIBRATION flag to your device in genesys_devices.c and 
recompile.

Regards,
Stef