# Re: Mustek 1200SP: Missing Lines

becka@rz.uni-duesseldorf.de
Mon, 3 Nov 1997 12:36:30 +0100 (MET)

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- In reply to: David Mosberger-Tang: "Re: Mustek 1200SP: Missing Lines"

> Stefan> The carriage also seems to backtrack at scsi transfer
> Stefan> boundaries.

> That's normal too. Mustek told me at one point it's impossible to
> avoid backtracking when the scsi buffer fills up. I'm not sure I
> believe that completely anymore since we were able to get rid of the
> backtracing in lineart & gray mode. But for color mode, there is
> indeed no solution other than using a huge scsi buffer (at least as
> far as we know).

It works fine with the 1.00 Firmware of my 12000SP, as it uses the
alternate ld correction which allows for doing without backtracking.

The technical reason seems to be that the scanner works somewhat like this :

CCD Paper
R\ /B
G--X--G
B/ \R

Thus the read, green and blue images are spaced against each other 1/72".
My scanner simply gives what is under the CCD and thus the images I get are
1/72" displaced against each other what is lateron corrected.

The other firmwares correct this on the scanner side, which forces
backtracking, as they _must_ go back 2/72" to get all info for the currently
transferred area.

Has anyone tried activating this hack for other scanners ? Maybe the "feature"
is there, too.

CU,ANdy

    --
    Andreas Beck              |  Email :  <becka@sunserver1.rz.uni-duesseldorf.de>

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