sane-bh - SANE backend for Bell+Howell Copiscan II series
The sane-bh library implements a SANE (Scanner Access Now
Easy) backend that provides access to Bell+Howell Copiscan
II series document scanners. The Copiscan II 6338 has
been the primary scanner model used during development and
testing, but since the programming interface for the
entire series is consistent the backend should work for
the following scanner models.
COPISCAN II 6338 Duplex Scanner with ACE
COPISCAN II 2135 Simplex Scanner
COPISCAN II 2137(A) Simplex Scanner (with ACE)
COPISCAN II 2138A Simplex Scanner with ACE
COPISCAN II 3238 Simplex Scanner
COPISCAN II 3338(A) Simplex Scanner (with ACE)
If you have a Bell+Howell scanner and are able to test it
with this backend, please contact firstname.lastname@example.org
with the model number and testing results. Additionally,
the author is curious as to the likelihood of using this
backend with the newer 4000 and 8000 series scanners. If
you have such a beast, please let me know.
The Bell+Howell Copiscan II series document scanners are
high volume, high throughput scanners designed for docu-
ment scanning applications. As such, they are lin-
eart/grayscale scanners supporting a fixed number of
fairly low resolutions (e.g. 200/240/300dpi). However,
they do have a number of interesting and useful features
suited to needs of document imaging applications. This
backend attempts to support as many of these features as
The main technical reference used in writing this backend
is the Bell and Howell Copiscan II Remote SCSI Controller
(RSC) OEM Technical Manual Version 1.5. The Linux SCSI
programming HOWTO, the SANE API documentation, and SANE
source code were also extremely valuable resources.
The latest backend release, additional information and
helpful hints are available from the backend homepage:
This backend expects device names of the form:
cial device name must be a generic SCSI device or a sym-
link to such a device. Under Linux, such a device name
takes a format such as /dev/sga or /dev/sg0, for example.
See sane-scsi(5) for details.
The contents of the bh.conf file is a list of device names
that correspond to Bell+Howell scanners. See sane-scsi(5)
on details of what constitutes a valid device name. Addi-
tionally, options can be specified; these lines begin with
the word "option". Each option is described in detail
below. Empty lines and lines starting with a hash mark
(#) are ignored.
The following options can be specified in the bh.conf
This option prevents the backend from sending any
optional frames. This option may be useful when
dealing with frontends which do not support these
optional frames. When this option is in effect,
the data is sent in a SANE_FRAME_GRAY frame. The
optional frames sent by this backend are:
SANE_FRAME_G31D, SANE_FRAME_G32D, SANE_FRAME_G42D
and SANE_FRAME_TEXT. These frames are generated
based on the compression and barcode options.
These frames are never sent in preview mode.
This option is used for debugging purposes and its
use is not encouraged. Essentially, it allows the
backend to initialize in the absence of a scanner.
This is useful for development and not much else.
This option must be specified earlier in the con-
figuration file than the devices which are to be
The backend configuration file (see also descrip-
tion of SANE_CONFIG_DIR below).
The static library implementing this backend.
The shared library implementing this backend (pre-
sent on systems that support dynamic loading).
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 /usr/local/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 spec-
ified directories. For example, setting SANE_CON-
FIG_DIR to "/tmp/config:" would result in directo-
ries "tmp/config", ".", and "/usr/local/etc/sane.d"
being searched (in this order).
If the library was compiled with debug support
enabled, this environment variable controls the
debug level for this backend. E.g., a value of 255
requests all debug output to be printed. Smaller
levels reduce verbosity.
With document scanners, automatic document feeder
(ADF) support is a key feature. The backend sup-
ports the ADF by default and returns SANE_STA-
TUS_NO_DOCS when the out-of-paper condition is
detected. The SANE frontend scanadf is a command
line frontend that supports multi-page scans. It
has been used successfully with this backend. The
SANE frontend xsane is an improved GUI frontend by
Oliver Rauch. Support for multi-page scans is
included in xsane version 0.35 and above.
Some models, such as the COPISCAN II 6338, support
duplex scanning. That is, they scan both sides of
the document during a single pass through the scan-
ner (the scanner has two cameras). This backend
supports duplex scanning (with the --duplex
option). The front and back page images are deliv-
ered consecutively as if they were separately
The scanner is capable of compressing the data into
formance as less data is passed from the scanner to
the host over the SCSI bus. The backend supports
these compression formats via the --g31d, --g32d,
--g42d options, respectively. Many SANE frontends
are not equipped to deal with these formats, how-
ever. The SANE frontend scanadf supports these
optional frame formats. The compressed image data
is written directly to a file and can then be pro-
cessed by a scan-script using the --scan-script
option. Examples of this are given on the scanadf
Automatic Border Detection
The scanner can automatically detect the paper size
and adjust the scanning window geometry appropri-
ately. The backend supports this useful feature
with the --autoborder option. It is enabled by
Batch Mode Scanning
The batch scan mode allows for maximum throughput.
The Set Window parameters must remain constant dur-
ing the entire batch.
The Icon function generates a thumbnail of the full
page image, that can be transferred as if it were a
separate page. This allows the host to quickly
display a thumbnail representation during the scan-
ning operation. Perhaps this would be a great way
of implementing a preview scan, but since a normal
scan is so quick, it might not be worth the trou-
Multiple sections (scanning sub-windows) can be
defined for the front and back pages. Each section
can have different characteristics (e.g. geometry,
compression). The sections are returned as if they
were separately scanned images. Additionally sec-
tions can be used to greatly enhance the accuracy
and efficiency of the barcode/patchcode decoding
process by limiting the search area to a small sub-
set of the page. Most Copiscan II series scanners
support up to 8 user-defined sections.
Support Barcode/Patchcode Decoding
codes are decoded and the data is returned to the
frontend as a text frame. The text is encoded in
xml and contains a great deal of information about
the decoded data such as the location where it was
found, its orientation, and the time it took to
find. Further information on the content of this
text frame as well as some barcode decoding exam-
ples can be found on the backend homepage.
Decoding a single barcode type per scan
The RSC unit can search for up to six different
barcode types at a time. While the code generally
supports this as well, the --barcode-search-bar
option only allows the user to specify a single
barcode type. Perhaps another option which allows
a comma separated list of barcode type codes could
be added to address this.
Scanning a fixed number of pages in batch mode
The separation of front and back end functionality
in SANE presents a problem in supporting the 'can-
cel batch' functionality in the scanner. In batch
mode, the scanner is always a page ahead of the
host. The host, knowing ahead of time which page
will be the last, can cancel batch mode prior to
initiating the last scan command. Currently, there
is no mechanism available for the frontend to pass
this knowledge to the backend. If batch mode is
enabled and the --end-count terminates a scanadf
session, an extra page will be pulled through the
scanner, but is niether read nor delivered to the
frontend. The issue can be avoided by specifying
--batch=no when scanning a fixed number of pages.
Revision 1.2 Patch detector
There is an enhanced patchcode detection algorithm
available in the RSC with revision 1.2 or higher
that is faster and more reliable than the standard
Bar/Patch code decoder. This is not currently sup-
Scan Mode Options:
Request a preview-quality scan. When preview is
set to yes image compression is disabled and the
image is delivered in a SANE_FRAME_GRAY frame.
Selects the scan mode (e.g., lineart,monochrome, or
--resolution 200|240|300dpi 
Sets the resolution of the scanned image. Each
scanner model supports a list of standard resolu-
tions; only these resolutions can be used.
--compression none|g31d|g32d|g42d [none]
Sets the compression mode of the scanner. Deter-
mines the type of data returned from the scanner.
none - uncompressed data - delivered in a
g31d - CCITT G3 1 dimension (MH) - delivered in a
g32d - CCITT G3 2 dimensions (MR, K=4) - delivered
in a SANE_FRAME_G32D frame
g42d - CCITT G4 (MMR) - delivered in a
NOTE: The use of g31d, g32d, and g42d compression
values causes the backend to generate optional
frame formats which may not be supported by all
Enable/Disable automatic image border detection.
When enabled, the RSC unit automatically detects
the image area and sets the window geometry to
--paper-size Custom|Letter|Legal|A3|A4|A5|A6|B4|B5 [Cus-
Specify the scan window geometry by specifying the
paper size of the documents to be scanned.
--tl-x 0..297.18mm 
Top-left x position of scan area.
--tl-y 0..431.8mm 
Top-left y position of scan area.
--br-x 0..297.18mm [297.18]
Bottom-right x position of scan area.
--br-y 0..431.8mm [431.8]
Bottom-right y position of scan area.
[Automatic Document Feeder]
Selects the scan source (such as a document
feeder). This option is provided to allow multiple
image scans with xsane; it has no other purpose.
Enable/disable batch mode scanning. Batch mode
allows scanning at maximum throughput by buffering
within the RSC unit. This option is recommended
when performing multiple pages scans until the
feeder is emptied.
Enable duplex (dual-sided) scanning. The scanner
takes an image of each side of the document during
a single pass through the scanner. The front page
is delivered followed by the back page. Most
options, such as compression, affect both the front
and back pages.
--timeout-adf 0..255 
Sets the timeout in seconds for the automatic docu-
ment feeder (ADF). The value 0 specifies the hard-
ware default value which varies based on the scan-
--timeout-manual 0..255 
Sets the timeout in seconds for semi-automatic
feeder. The value 0 specifies the hardware default
value which varies based on the scanner model.
Check ADF Status prior to starting scan using the
OBJECT POSITION command. Note that this feature
requires RSC firmware level 1.5 or higher and dip
switch 4 must be in the on position. NOTE: This
option has not been tested extensively and may pro-
duce undesireable results.
Enables the scanner's control panel for selecting
image enhancement parameters. When the option is
set to no the following options are used to control
image enhancement. See the Bell+Howell scanner
users' guide for complete information on ACE func-
--ace-function -4..4 
Specify the Automatic Contrast Enhancement (ACE)
Specify the Automatic Contrast Enhancement (ACE)
--brightness 0..255 
Controls the brightness of the acquired image.
Ignored for ACE capable scanners.
--threshold 0..255 
Select minimum-brightness to get a white point.
Ignored for ACE capable scanners.
--contrast 0..255 [inactive]
Controls the contrast of the acquired image. This
option is not currently used by the scanner (and
perhaps never will be).
Swap black and white, yielding a reverse-video
--icon-width 0..3600pel (in steps of 8) 
Width of icon (thumbnail) image in pixels.
--icon-length 0..3600pel (in steps of 8) 
Length of icon (thumbnail) image in pixels.
--barcode-search-bar <see list> [none]
Specifies the barcode type to search for. If this
option is not specified, or specified with a value
of none, then the barcode decoding feature is com-
pletely disabled. The valid barcode type are:
--barcode-search-count 1..7 
increase performance. If you are having trouble
recognizing barcodes, it is suggested that you
increase this option to its maximum value (7).
--barcode-search-mode <see list> [horiz-vert]
Chooses the orientation of barcodes to be searched.
The valid orientations are:
--barcode-hmin 0..1660mm 
Sets the barcode minimum height in millimeters
(larger values increase recognition speed). Of
course the actual barcodes in the document must be
of sufficient size.
--barcode-search-timeout 20..65535us 
Sets the timeout for barcode searching in millisec-
onds. When the timeout expires, the decoder will
stop trying to decode barcodes.
--section <string> 
Specifies a series of image sections. A section
can be used to gather a subset image or to provide
a small area for barcode decoding. Each section is
specified in the following format (units are in
Multiple sections can be specified by separating them with
For example 76.2x25.4+50.8+0:frontbar identifies an area 3
inches wide and 1 inch high with a top left corner at the
top of the page two inches from the left hand edge of the
page. This section will be used for barcode decoding on
the front page only.
For example 50.8x25.4+25.4+0:frontbar:front:g42d identi-
fies an area 2 inches wide and 1 inch high with a top left
corner at the top of the page one inch from the left hand
edge of the page. This section will be used for barcode
decoding on the front page as well as generating an image
compressed in g42d format.
Ordinarily barcodes are searched in the entire image.
However, when you specify sections all barcode searching
is done within the specific sections identified. This can
front - generate an image for the front page sec-
back - generate an image for the back page section
frontbar - perform barcode search in front page
backbar - perform barcode search in back page sec-
frontpatch - perform patchcode search in front page
backpatch - perform patchcode search in back page
none - use no image compression
g31d - use Group 3 1 dimension image compression
g32d - use Group 3 2 dimensions image compression
g42d - use Group 4 2 dimensions image compression
If you omit a compression functioncode, the full page com-
pression setting is used. If you specify multiple com-
pression functioncodes, only the last one is used.
--barcode-relmax 0..255 
Specifies the maximum relation from the widest to
the smallest bar.
--barcode-barmin 0..255 
Specifies the minimum number of bars in Bar/Patch
--barcode-barmax 0..255 
Specifies the maximum number of bars in a Bar/Patch
--barcode-contrast 0..6 
Specifies the image contrast used in decoding. Use
higher values when there are more white pixels in
--barcode-patchmode 0..1 
Controls Patch Code detection.
This is a new backend; detailed bug reports are welcome --
and expected ;)
If you have found something that you think is a bug,
please attempt to recreate it with the SANE_DEBUG_BH envi-
ronment variable set to 255, and send a report detailing
the conditions surrounding the bug to
sane-scsi(5), scanimage(1), scanadf(1)
The sane-bh backend was written by Tom Martone, based on
the sane-ricoh backend by Feico W. Dillema and the bnhscan
program by Sean Reifschneider of tummy.com ltd.
Man(1) output converted with