[sane-devel] Benq 5150C / 5250C users: please test
Oliver.Schwartz at gmx.de
Mon Jan 9 23:24:13 UTC 2006
> Ok, I did some testing with my BenQ 5150C.
> My first try was in 300dpi color mode (because this was default).
> There are no color stripes anymore. However, the scanned area was
> not very wide. Although the full available range
> ((0,0)x(216.0,297.0)mm^2) was selected in xscanimage. The resulting
> image had only 109 mm in width and approx. 145 mm in height
> (measured with millimetre graph paper)
> This is independent of selected resolution and colour mode.
Looks like the measurements are off by a factor of 2. That should be
easy to fix.
> 'Gray' doesn't work. It still results in very distorted Images.
> When doing 'gray' with xsane there is a message box saying "Backend
> sends more image data than it defined in parameters", after
> scanning in preview mode.
Hm, ok. The backend currently always sends some static calibration
data for color mode. I'll try to get some gray scale mode calibration
data as well.
> 'Halftone' sends wrong colours, and sometimes the same patterns as
> gray. In xscanimage, preview crashes in this mode.
This may be related. However, a lot of modern scanners don't support
halftoning at all. Does the windows driver offer something similar?
> > At present the calibration algorithm for the 5150 / 5250 is
> > unknown. The calibration data sent to the scanner is currently
> > some static data which may or may not work for all scanners.
> I'm not a hardware developer. But if you need any data, be free to
> ask. But as my attempt to sniff on the USB-bus in Windows fired up
> the whole system and I could not scan anymore until the next
> reinstall of W2K, I won't do that anymore.
I have some data samples, but the hard part is to make an educated
guess on the used algorithm.
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