[sane-devel] Acer 620ST

[Oliver Schwartz]

Hi,

> I have got a scanner called Acer 620 ST.
> It's running properly using the snapscan-backend.
> sgcheck shows something like:  FlatbedScanner17
>
> My question is:
> Why the xsane, saintwain or xscanimage frontends "just" provide the
> maximum scanning resolution of 600 dpi, though the scanner itself
> is capable to scan at 1200dpi (unfortunally only under Windows,
> yet)? Is there a way to include that resolution as well?

The scanner has a resolution of 600x1200 dpi, i.e. the optical 
resolution is 600 dpi whereas the stepper motor that moves the tray 
has a resolution of 1200 dpi. 

The backend is currently limited to the optical resolution of the 
scanner. All higher resolution require an interpolation algorithm in 
the backend, and I never got around to implement a decent one. It's 
on my list though, but with very low priority.

You also have to consider that the "real" resolution of the scanner is 
probably less than the mechanical resolution anyway. There was a test 
once in c't (german computer magazine) where they measured the real 
resolution of scanners. Most scanners have difficulties in reaching 
even 600 dpi, due to limitation of the optics involved.

Regards,

Oliver