> Gesendet: Freitag, 27. September 2013 um 21:16 Uhr > Von: Stef <stef.dev at free.fr> > An: "c...... g......" <muddlehead at gmx.net>, sane-devel at > lists.alioth.debian.org > Betreff: Re: [sane-devel] sane-genesys options > > On 27/09/2013 13:50, c...... g...... wrote: > > Hi, > > > > is it possible to modify the calibration offsets for the genesys backend? I > > could not find any documentation for this. I know that the calibration is > > written into a file ~/.sane/... What is the format of this file? > > > > Thanks, > > Christian > > > Hello, > > there is a make target to generate doxygen files from the genesys > backend. The file only stores the result of calibration. I don't think > you want to modify it directly. > Why are you trying to modify offsets ? > > Regards, > Stef >
Hi Stef, thanks for your reply. The need to override the automatic calibration settings stems from my special use of the scanner (hp g4050). I try to scan in two different modes, one with the internal light on, the other with the internal light off and an external infrared source on. (In both modes I have to keep the scanner cover open.) When the scanner calibrates, it uses the white calibration strip built into it's case. Using the calculated calibration values the images are not useable for my purpose because of the different lighting conditions while scanning. So I opened the scanner and covered the calibration strip with dark tape for testing. Afterwards it was possible (at least for one of the two scan settings) to get images which were useable but still of poor quality. I'm sure that if I could manually override the calibration values, it would be possible to improve the image quality. (some backends have options to override rgb offsets and gains but I think this is not true for the genesys backend?). Modifying the calibration file would be a temporal workaround but maybe I should implement the required options directly into the backend. There is another issue I have with the IR-settings. The HP g4050 has a built in IR-filter which can be flipped out of the optical path by a magnetic switch. I think it would be necessary to do some reverse engineering to get this switch working. For the moment I've solved this issue by fixing the IR-filter manually but it would be great to have this done by the genesys backend. Can you suggest me some free (win7/win8 64 bit, MacOs should be possible too) software to sniff the usb communication? Regards, Christian
