[sane-devel] Avision AV220 Questions (LED digit, Buttons, Backends, Paper size)

[m. allan noah]

On Sun, Feb 1, 2009 at 10:42 AM, Crypto <crypto at online.de> wrote:
> Hi,
>
> I bought a used Avision AV220 document scanner recently and I am mostly happy
> with it. Fast duplex colour scanning of sheets, and it is so silent compared
> to the scanner I used before.
>
> Now I have got a few questions:
>
> 1.) The scanner has got a single digit LED, an arrowed button, two more
> buttons labelled "Cancel" and "Scan". Though I can imagine what the latter
> two might do, I cannot guess the meaning of the digit and the arrow button. I
> can switch the number displayed from 1 to 9 and then to 1 again, but cannot
> see a meaning of that. I downloaded a manual for this scanner, in which the
> LED and the buttons are displayed but not explained. So what do these do?

the windows software probably gives you a config screen to assign
software functions to each number. something like: 1='300dpi pdf'
2='200dpi email', etc. Something similar can be achieved with sane, if
you are willing to work at it. look in the experimental tree of our
cvs server, and search this mailing list's archives.

> 2.) In scanning software such as gscan2pdf etc. there is an option to set
> contrast and brightness. Brightness goes from -100 (I suppose to make scans
> darker) to +100 (makes scans brighter). I can set this option to positive
> values and get brighter scans, but when I attempt to get darker scans I get
> an error message "Unknown message: Argument "" isn't numeric in subtraction
> (-) at /usr/bin/scanimage.pl line 357". This also happens if I use different
> backends for scanning such as scanadf.pl. In scanadf.pl it's line 380 but
> same error otherwise.

sounds like a bug in gscan2pdf. does it work when you call scanimage
or scanadf directly with negative arguments?

> 3.) After I enter sheets into the sheetfeeder, I select the page size and scan
> them. BUT: regardless which page size I have entered there always is a slight
> cut-off of the very top part of the sheet. The scanner always draws in the
> first page of a pile of sheets so there is no way for me to see if it did
> that correctly. Is this a problem of the back end that I use?

don't know. does it happen with every sheet? does it happen with
command line programs like scanimage?

>
> 4.) Is the scanning area of a sheet influenced by the two red paper guides in
> any way? Or is only the paper size setting in the backend influencing the
> page size and the area that is scanned?

I doubt there are sensors attached to the guides, so software must be
used to set the page size. I prefer the backend to handle this by
exposing two paper size options in addition to the four scan area
coordinates. The avision backend requires the front-end to make do
without.

allan
-- 
"The truth is an offense, but not a sin"