as6edriver  development release 0.11   1/11/2000
revised	for development release 0.2	   1/23/2000
revised for development release 0.22   1/30/2000
revised for development release 0.4	   3/7/2000
revised for development release 0.41   4/17/2000


To use the SANE interface, you should just have to call xsane or xscanimage
and select the as6e:as6edriver from the device menu.  (or select Xtns xsane
if you are using it as a GIMP plugin)  For xsane, it is noteworthy that the
visible brightness and contrast adjustments are post-scan corrections.  The
backend supports it's own brightness and contrast controls, which can be found
with the "view/show standard options" menu.  The (rather odd) default values
are identical to the adjustments used in command line mode.  Adjust the values
to match your own screen and preferences.  You can save the settings with the
"preferences/save device settings" menu option.

If this doesn't work, try the driver in command line mode to see if the
problem is with the driver or with SANE.

To use the driver in command line mode:

1. Make sure your scanner is properly connected and plugged in.

2. as6edriver

3. Follow the text instructions on the screen.

4. It now takes command line options:
	-c scans from command line parameters {dpi color left right front back}
		example : ./as6edriver -c 200 lineart 0 8.5 0 11 (this scans
		a letter size page at 200 dpi in lineart mode)
		Parameters for 	dpi are 	50, 100, 200, 300
			"	color	     	color, grey, lineart
			"	left and right	0 - 8.5 inches (1 inch = 25.4 mm)
			"	front and back 	0 - 11.7  "         "
			
	-m switches pport mode
	-t enters the test suite

At startup, the driver prints a message stating which parallel port mode it is
using. ("Using EPP mode", "Using byte mode", or "Using nibble mode")  EPP mode
is the fastest, byte mode is about half as fast, and nibble mode is pathetic.
If it is not using EPP mode, try changing the parallel port settings in your
BIOS.  It should either be set to EPP or ECP+EPP.  If both of these are
available and one doesn't work, try the other.  To get information about your
parallel ports, type "dmesg" at the command line.  It should have a line which
reads something like "parport0:  PC-style at 0x378 (0x778) [SPP,ECP,ECPPS2,ECPEPP]".
It should have the notation "EPP" or "ECPEPP" in it for it to work in EPP mode.
Make sure thst the port information matches the file "/etc/as6e.conf.

If you are not usnig SANE, the output file is named as6etemp.pnm.  You MUST
copy and rename it before starting a second scan.  The program will overwrite
the old file if you do not.  Obviously, this will change in future releases.

Use the GIMP, or another graphics program to crop, edit and store the
image.  The AS6E outputs pnm files, which are as bulky as they come.  You should
store your images in PNG or another compressed format.

Image quality issues:

The vertical lines problem has been solved as of version 0.22.  Other
quality problems persist.  Occasionally one can find horizontal lines in 200
dpi color scans.  50 dpi in greyscale also sometimes has problems.  These small
problems are probably dealt with in the windows driver with a small default
blur.  In nibble mode, image quality problems are significantly worse.  Try to
scan in a better port mode by changing the parallel port settings in your BIOS
as above.  If this fails, do a Gaussian blur in the GIMP, followed by a sharpen
to correct the problems.

When one scans a printed image, one frequently gets a series of light and dark
dots in the image in a geometric pattern. This is called "moire'" and is the
result of the printing technique of using patterns halftone dots to simulate
a wider variety of colors.  They can be eliminated by doing a "Gaussian blur"
in the GIMP (right-click filters/blur/Gaussian blur (IIR)) followed by a
by a "sharpen" process (right-click filters/enhance/sharpen).  Unfortunately,
the GIMP routines are rather slow.  The Windows driver for the AS6E, at least
in its more recent versions, eliminates moire' automatically, probably with the
routine I described above.  I have also read about a "descreening" function in
image processing software, which detects and removes moire'.  I don't know
if it uses the same routine I described  above, or another more advances one.
Writing a detector for moire' shouldn't be too difficult.  I'll try to find
out if a descreening function exists in any open source software, and look into
implementing it somewhere into this project, though perhaps not in the low level
driver.  Otherwise, I could use an automatic blur - sharpen option, perhaps
speeding it up by using integer math. (The GIMP uses floating point math for
flexibility).  The blur - sharpen routine can eliminate many image quality
problems, as well as moire'.  Please let me know which GIMP setting work best
for you, as I am new to this.  As of a week ago, I knew absolutely nothing
about image processing.


The capabilities of the driver are as follows:

It now works in EPP, byte and nibble modes.  This has cut scan times roughly
in half from when it supported only byte and nibble modes.  The program
prints the mode it is using at startup.  If you find that it uses nibble mode,
try changing the parallel port mode in your BIOS.  There are problems with
ECP-EPP on some systems (mine, for instance).  This is a hardware issue, and
not a problem with the driver, but I would still appreciate reports of any
problems.  I can,at least, include them in future versions of the documentation.

Email me at yossarian@users.sourceforge.net.

Currently lineart mode is emulated in software.  Obviously, anything you can do
to help me would be welcome.  Project info is available at
http://as6edriver.sourceforge.net .

For those of you interested in Free/Open Source software, you really should
take a look at Sourceforge.  It provides CVS, web,ftp, etc., completely free to
all sorts of projects. It's run by VA Linux as a way of giving back to the
community.  Any updated information about the driver will appear there first.

If you find bugs (and no doubt you will) please use the same link to inform me
of them.  Please include detailed information about your system, including
CPU, clock speed, parallel port type, and the make of the motherboard if you
know it.  I'll post info on the web page about how to find out what sort of
parallel port you have.

Most of the debugging code now outputs to the file "/var/tmp/as6e.log", please
include this file in any bug reports.


Good luck!

Eugene Weiss


