On Thursday 13 January 2005 04:12, Alvaro Figueiredo wrote: > On Wed 12 Jan 2005 08:51, Gerhard Jaeger wrote: > > Hi, > > > > the pictures are too bright. You need to tweak the threshold > > for the binary stuff. This is controlled by the option > > --brightness > > which goes from -100 (completely black) to 100 (completely > > white). The default setting is 0. You might try -20 in your case! > > > > I'll do some checks here. > > > > Ciao, > > Gerhard > > > > Hi, > > I tried several values to the option --brightness. The scan quality > improved a lot! The best result that I got was using the value -95. > Seems that I need another scale. > > After that, the image center got ok, while its sides ended dark. > Then, I included the option --warmup-time with value 0 and the > darkness on borders reduced. > > The resulting images are doc1095.pdf, doc2095.pdf and doc3095.pdf. > The script scandocument was employed to generate these. All files > was published on > > http://alvarof.freeshell.org/sane/ > > if you wish to see them. > > I think that my immediate problem was solved. But, tell me if you > want to do any test. I would be glad to help. > > Thank You by your time. > > > On Wednesday 12 January 2005 02:41, Alvaro Figueiredo wrote: > > > At Tue 11 Jan 2005 06:25, Gerhard Jaeger wrote: > > > > Hi, > > > > > > > > On Tuesday 11 January 2005 05:41, Alvaro Figueiredo wrote: > > > > > Hi, all. > > > > > > > > > > I recently bought a Canon LIDA 20, a USB scanner. It readly > > > > > worked on my Linux 2.6 box, but its scan quality is really > > > > > much worse than Windows 98 driver's scan output. It is a > > > > > dual boot box. > > > > > > > > > > I am scanning regular text documents, like the sample > > > > > bellow. > > > > > > > > > > scanimage --resolution 300 --mode Binary -x 210mm -y 297mm > > > > > > > > > > The Windows output is almost perfect, like a photocopy. The > > > > > sane's output seems to have much less resolution and misses > > > > > some portions of text that is not black. I am using the > > > > > same mode (lineart) and resolution (300dpi) on Linux / sane > > > > > and Windows. I can send both outputs, if anyone request it > > > > > (near 150k each, in PDF). > > > > > > > > please send it to me. > > > > > > I made available three documents scanned on Linux (sane) and on > > > Windows (manufacturer's driver). They are doc1???.pdf, > > > doc2???.pdf and doc3???.pdf (??? is lin or win). I did ran a > > > sample with debug enabled and published it all at: > > > > > > http://alvarof.freeshell.org/sane/ > > > > > > > > I have no scanning experience, but I had tried almost all > > > > > options of scanimage without significative improvement. > > > > > > > > > > Am I missing something, here? > > > > > > > > Probably not. > > > > > > > > > Follow some system information. > > > > > > > > > > scanimage --version > > > > > scanimage (sane-backends) 1.0.14; backend version 1.0.14 > > > > > > > > you might update to 1.0.15. > > > > > > My Linux distro uses RPM, and I already keep it updated. I will > > > try upgrade sane later on, with alternative packages. > > > > > > > > scanimage -L > > > > > device `plustek:libusb:001:004' is a Canon > > > > > N670U/N676U/LiDE20 USB flatbed scanner > > > > > > > > > > sane-find-scanner > > > > > found USB scanner (vendor=0x04a9 [Canon], product=0x220d > > > > > [CanoScan], chip=LM9832/3) at libusb:001:004 > > > > > > > > Could you please to the scan again, enabling the debug > > > > output, and send me that too? export SANE_DEBUG_PLUSTEK=20 > > > > > > > > Ciao, > > > > Gerhard > > > > > > I did not scanned color pictures yet. I do not know if it > > > presents some anomaly. > > > > > > Please, let me know if I may help you with more information or > > > if I could make more tests. > > > > > > Thank You by your attention. > > -- > Alvaro Figueiredo > [email protected]
Hi Alvaro, from the tests you made, we can see, that the binary scans seems still to be too bright. I will do some tests here on my LiDE30 and also on some other devices, maybe the settings for the binary-modes are completely wrong :( It seems, that this mode is rarely used... Thanks for the tests and pix. Gerhard
