[sane-devel] Paper size detection for Fujitsu fi-5110eoxm (sane-fujitsu)?

[Adam Richter]

Hello,

	At the outset, let me say thank you to the sane-fujitsu
authors (according to fujitsu.c, Randolph Bentson, Frederik Ramm,
Oliver Schirrmeister, and M. Allan Noah) for providing a backend that
has been working so well with my Fujitsu fi5110eoxm double sided
sheet fed scanner for almost two years.

	I am interested in adding automatic page length detection,
similar to what the avision driver does I would like some pointers to the relevant technical specifications of the protocol used by the scanners that sane-fujitsu supports.  I do not see that feature in the cvs snapshot of 2009.03.22, but I may have missed something.  I am not saying that I am committing to implement this, but I would like to get the relevant technical specifications and see how hard it would be to try.

        If I get really ambitious, perhaps I might also try to implement a "bottom margin" option to scan a bit past the end to accomodate pages scanned at a slight angle, and perhaps some support for the "scan" button also along the line of what avision has.

	Just to confirm that I have done some basic sanity checks
related to this request, I will mention that scanner appears to
support page length detection, according to these web pages:

	"Automatically recognizes document type by paper length"
		http://scansnap.fujitsu.com/spec-mac.html

	"Automatic de-skew and paper size detection"
		http://www.fujitsu.com/us/services/computing/peripherals/scanners/discontinued/fi-5110eoxm.html (click on "Features" tab)

	As another sanity check, I should mention that I have done
some web searches and skimmed the sane-devel mailing list to
try to see if anyone is already working on this, and have not
found any hits.

	At first, I was hopeful that since the fujitsu backend's help
text mentioned that it wanted to know the page size in order to do jam
detection, that perhaps the driver was periodically querying the paper
detection and scrolling the paper from the host computer, but a quick
look at the source code seems to indicate that the paper size
information is simply sent to the scanner, I guess locally controls
the scrolling of the paper feeder.  So, I think I need more
documentation about the protocols used by this scanner to figure out
how to implement support for automatic paper length detection.

	I assume that there is no automatic paper width detection, but
would be happy to be corrected if I am wrong, especially because the
images that I receive for the areas left and right of the paper being
scanned seem to have some noise (that is, they are not columns of
exactly one solid color), so I will probably have to do some research
to determine if I can find software that reliably detects the paper's
left and right edges.

	Finally, on a different subject, but one related to protocol
documentation, I notice that nineteen .c files in
sane-backends-2009-03-22/backends contain both the terms "USB" and
"SCSI", so it looks like there are multiple drivers that claim to
encapsulate some kind of scsi commands over USB.  This makes me wonder
if there might be some SCSI standards on t10.org and/or USB device
class specification on www.usb.org that might describe what most of
these drivers do and perhaps provide an opportunity to factor out some
common code.  On the other hand, if the fujitsu scanners are basically
running a custom protocol, then I probably need some documents from
Fujitsu, which I am sure would be helpful in any case.

	Any pointers would be appreciated.  Thanks in advance.

Adam Richter