[Hp5400backend-devel] Re: changes in calibration for high resolution scans

[Martijn v. O. <kl...@sv...>]

On Thu, Mar 06, 2003 at 11:17:51AM +0100, Thomas Soumarmon wrote:
> Hi,
>=20
> Bertrik was right about the problem of calibration for high resolution sc=
ans.=20
> I enlarged the calibration data sent, depending on dpi and it works bette=
r.
> There are still small vertical black areas =3D> calibration data is not c=
orrect.
> Anyway, calibration data have to be fully computed because currently it i=
s the=20
> same small amount of data replicated as much as needed.

Yep, that'd be because the calibration data has areas with zeros which
represent the areas outside the glass. By repeating the same data you'll get
black areas in the middle of the picture.

> It seems that 2400 dpi is broken so I disabled the 2400 dpi option of the=
 gui=20
> for the moment. You have to define SUPPORT_2400_DPI in sane-hp5400.c to h=
ave=20
> it back.

Yep, the Xsize value from the scanner overflows. I'm about to commit a fix
for that. In theory the Yvalue can also overflow but I havn't seen what
happens there.

> I commited the changes as it makes the scanner works better with 1200 dpi=
.=20
> I'll have a look later to see how to calculate the correct data of the=20
> calibration.

Well, 600dpi looks good so far.

--=20
Martijn van Oosterhout   <kl...@sv...>   http://svana.org/kleptog/
> Support bacteria! They're the only culture some people have.