Provided by: libsane_1.0.19-23ubuntu7_i386 bug

NAME

       sane-canon_pp  -  SANE backend for Canon CanoScan Parallel Port flatbed
       scanners

DESCRIPTION

       The sane-canon_pp library implements a SANE (Scanner Access  Now  Easy)
       backend that provides access to the following Canon flatbed scanners:

              CanoScan FB320P
              CanoScan FB620P
              CanoScan FB330P
              CanoScan FB630P
              CanoScan N340P
              CanoScan N640P
              CanoScan N640P ex

       No USB scanners are supported and there are no plans to support them in
       the future.  Other projects are working on support  for  USB  scanners.
       See  the  PROJECTS file for more detail.  The FB310P and FB610P are re-
       badged Avision scanners which use  a  different  command  set,  so  are
       unlikely to be supported by this backend in the future.

       IMPORTANT:  this is alpha code. While we have made every effort to make
       it as reliable as possible,  it  will  not  always  work  as  expected.
       Feedback  is  still  appreciated.   Please  send any bug reports to the
       maintainers as listed on the web page (listed in SEE ALSO below).

DEVICE NAMES

       This backend expects device names of the form presented by libieee1284.
       These names are highly dependent on operating system and version.

       On  Linux  2.4  kernels this will be of the form parport0 or older (2.2
       and before) kernels may produce names like 0x378 (the base  address  of
       your  port)  or simply 0 depending on your module configuration.  Check
       the contents of /proc/parport if it  exists.   If  you  don’t  want  to
       specify  a default port (or don’t know its name), the backend should be
       able to detect which port your scanner is on.

CONFIGURATION

       The contents of the canon_pp.conf file is a list  of  options  for  the
       driver to use.  Empty lines and lines starting with a hash mark (#) are
       ignored.

       The supported options are currently ieee1284, calibrate, init_mode, and
       force_nibble

       Option  ieee1284  port-name  defines  which port to use.  The format of
       port-name is OS dependent, based on the names presented by libieee1284.
       Please only have one of these lines, or all but one will be ignored.

       Option calibrate cal-file [port-name] defines which calibration file to
       use on a per-port basis.  If you only have one parport,  the  port-name
       argument may be omitted - but be careful as this will cause problems on
       multi-scanner systems.  You may have as many  of  these  lines  as  you
       like,  as  long  as  each  has  a  unique  port  name.  The tilde (‘~’)
       character is acceptable and will be expanded to the value of  the  HOME
       environment.

       Option   init_mode   <AUTO|FB620P|FB630P>   [portname]   defines  which
       initialisation (wake-up) mode to use on a per-port basis.  If you  only
       have one parport, the portname argument may be omitted - but be careful
       as this may cause problems on multi-scanner systems.  You may  have  as
       many  of  these  lines  as  you like, as long as each has a unique port
       name.   The  valid  initialisation  modes  are  FB620P  (which  strobes
       10101010 and 01010101 on the data pins), FB630P (which strobes 11001100
       and 00110011 on the data pins) and AUTO, which  will  try  FB630P  mode
       first  then  FB620P  mode  second.  The FB620P mode is also used by the
       FB320P.  The FB630P mode is used by the FB330P, N340P, and N640P.

       Option force_nibble forces the driver to use nibble mode  even  if  ECP
       mode  is  reported  to work by libieee1284.  This works-around the rare
       issue of ECP mode being reported to  work  by  the  library,  then  not
       working.

TIPS

       Hit  the  "Calibrate"  button  before scanning.  It vastly improves the
       quality of scans.

       To enable automatic detection of your scanner, uncomment the "canon_pp"
       line from /etc/sane.d/dll.conf

FILES

       /etc/sane.d/canon_pp.conf
              The   backend   configuration  file  (see  also  description  of
              SANE_CONFIG_DIR below).

       /usr/lib/sane/libsane-canon_pp.a
              The static library implementing this backend.

       /usr/lib/sane/libsane-canon_pp.so
              The shared library implementing this backend (present on systems
              that support dynamic loading).

ENVIRONMENT

       SANE_CONFIG_DIR
              This environment variable specifies the list of directories that
              may contain the configuration file.  Under UNIX, the directories
              are  separated  by a colon (‘:’), under OS/2, they are separated
              by a semi-colon  (‘;’).   If  this  variable  is  not  set,  the
              configuration  file  is  searched  in  two  default directories:
              first,  the  current  working  directory  (".")  and   then   in
              /etc/sane.d.  If the value of the environment variable ends with
              the directory separator character, then the default  directories
              are  searched  after  the explicitly specified directories.  For
              example, setting SANE_CONFIG_DIR to "/tmp/config:" would  result
              in   directories  "tmp/config",  ".",  and  "/etc/sane.d"  being
              searched (in this order).

       SANE_DEBUG_CANON_PP
              If the library was compiled with  debug  support  enabled,  this
              environment  variable controls the debug level for this backend.
              Higher debug levels increase the verbosity of the output.

              Example: export SANE_DEBUG_CANON_PP=4

NOTES

       Features available in the Windows interface

       Brightness and Contrast
              These are not implemented, and probably never  will  be.   These
              appear  to  be  implemented entirely in software.  Use GIMP or a
              similar program if you need these features.

       Descreen Mode
              This appears on our first analysis to be just oversampling  with
              an  anti-aliasing  filter.   Again,  it  seems to be implemented
              entirely in software, so GIMP is your best bet for now.

       Gamma Tables
              This is under investigation, but for now  only  a  simple  gamma
              profile  (ie:  the  one  returned  during  calibration)  will be
              loaded.

       Communication Problems

       ECP mode in libieee1284 doesn’t always work  properly,  even  with  new
       hardware.   We believe that this is a ppdev problem.  If you change the
       configuration file to include force_nibble , the problem will go  away,
       but you will only be able to scan in nibble mode.

       Sometimes  the  scanner  can  be  left in a state where our code cannot
       revive it.  If the backend reports no scanner present,  try  unplugging
       the  power  and plugging it back in.  Also try unplugging printers from
       the pass-through port.

       The scanner will not respond correctly to our commands when  you  first
       plug  in  the  power.   You  may find if you try a scan very soon after
       plugging in the power that the backend will incorrectly report that you
       have  no  scanner  present.  To avoid this, give it about 10 seconds to
       reset itself before attempting any scans.

       Repeated Lines

       Sometimes at high resolutions (ie. 600dpi) you will notice lines  which
       appear  twice.  These lines correspond to points where the scanner head
       has stopped during the scan (it stops  every  time  the  internal  64kb
       buffer  is  full).   Basically  it’s  a  mechanical  problem inside the
       scanner, that the tolerance of  movement  for  a  start/stop  event  is
       greater  than 1/600 inches.  I’ve never tried the windows driver so I’m
       not sure how (or if) it works around this problem, but as we don’t know
       how  to  rewind  the  scanner  head  to  do  these  bits again, there’s
       currently no nice way to deal with the problem.

       Grey-scale Scans

       Be aware that the scanner uses the green LEDs to read grey-scale scans,
       meaning  green coloured things will appear lighter than normal, and red
       and blue coloured items will appear  darker  than  normal.   For  high-
       accuracy  grey-scale  scans  of colour items, it’s best just to scan in
       colour and convert to grey-scale in graphics software such as the GIMP.

       FB620P/FB320P Caveats

       These  models  can  not  be  reset  in the same way as the others.  The
       windows driver doesn’t know how to reset them either - when  left  with
       an inconsistent scanner, it will start scanning half way down the page!

       Aborting is known to work correctly on the FB*30P models, and is  known
       to be broken on the FB*20P models.  The FB620P which I tested on simply
       returns garbage after a scan has been aborted using the method we know.
       Aborting  is  able to leave the scanner in a state where it can be shut
       down, but not where another scan can be made.

SEE ALSO

       sane(7), sane-dll(5)  http://canon-fb330p.sourceforge.net/

AUTHOR

       This backend is primarily the work of Simon Krix (Reverse Engineering),
       and Matthew Duggan (SANE interface).

       Many  thanks  to  Kevin  Easton  for his comments and help, and Kent A.
       Signorini for his help with the N340P.