Getting compressed B/W image data from Fujitsu M3096GXm scanner

From: Armistead, Jason (armistej@oeca.otis.com)
Date: Thu Feb 01 2001 - 22:09:03 PST

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    Hi

    We have a Fujitsu M3096GXm SCSI scanner ("m" suffix means it's fitted with a
    CMP-2 compression board + 4Mb extra RAM) connected to a PC running RedHat
    Linux 7.0 (i586 kernel 2.2.16-22) It works OK using the fujitsu-m3096g
    driver (since after all the GX model is basically just the G model with a
    few extra features), but it doesn't support the compression board (I'm not
    even sure if that board was supported on the G model). I can read the
    resulting TIFF file using GIMP or other image manipulation program.

    I'd like to have SANE get the bitonal data directly from the scanner in
    CCITT G4-2D (otherwise called MMR = Modified Modified READ = ITU T.6 = Fax
    Group 4) format. That saves me having to work out a way to post-process the
    raw (uncompressed) data stream into that format using a separate program
    other than SANE. I can just modify SANE to output the correct TIFF headers
    as it goes.

    So, in looking at all the backend drivers for SANE, I notice that none of
    them appear to support reading compressed data from the scanner. The
    fujitsu-m3096g driver that comes with SANE 1.0.4 seems to be a fairly
    rudimentary driver supporting not much more than the minimum level of base
    functionality (and I can't really complain since the author no doubt got it
    to do what he needed and like all of us is probably too busy to devote more
    time to a "pet project" like SANE)

    Yet the SCSI-II specification for scanners (refer section 15), indicates
    that the SET WINDOW command allows a bytes at offset 0x20 for compression
    type, and 0x21 for the compression argument ("K" factor for MR = G3-2D
    compression).

    I can't believe that NO scanner supports sending compressed data to the
    initiator, so I can only surmise that for some reason nobody has tried to
    implement it. I would have thought that some of the top-end high volume
    scanners like Bell & Howell would surely support on-board compression, and
    that someone, somewhere might have added them to SANE.

    Any ideas, suggestions ? Sample code (or attempts at it) most welcome ...

    Regards

    Jason Armistead
    Senior Systems and Software Engineer
    Continuation Engineering
    OTIS Minto, Australia
    +61-2-9827-3742 (phone)
    +61-2-9827-3606 (fax)
    PABX speed dial 6214 (mobile) 

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