[sane-devel] How to get infrared image data with sane on an epson v700 scanner?

[Olaf Meeuwissen]

Alain Culos <sane-devel at asoundmove.net> writes:

> I have managed to get scanimage to produce some results with IR mode
> from my scanner thanks to your help Olaf. However I seem to have a few
> problems with the data: format and contents.
>
> Scanimage seems to work normally with plain regular reflective scans
> (paper). So that's a good start.
>
>
> 1/ Format issues:
>
> First it seems that the tiff or the pnm produced by scanimage is
> interpreted strangely: it shows as if it was three frames, side by
> side, of B&W data.

Like m. allan noah said in another mail in this thread, time to roll up
your sleeves.  The scanimage sources have no support for SANE_FRAME_IR
whatsoever.  I had a quick glance at frontend/scanimage.c and it looks
like you will need to patch up the scan_it() function in there.  Note,
though, that I am not familiar with that code so you are basically on
your own there.  I also don't know what kind of data the frontend can
expect when the backend says it'll provide SANE_FRAME_IR.

> [snip]
>
> 2/ IR content issues:
>
> It seems like the data itself is not proper IR data. Without TPU, it
> looks like plain light, but I can't tell whether it is RGB or just
> grayscale. Ok, maybe that's normal, since I would expect the IR to
> only be active with the TPU.
>
> With TPU it looks like Grayscale data split in three separate
> images. It certainly does not look like IR data (I expect dark flecks
> of dust and only very slight shades of light gray based on the actual
> RGB pixel colour for the slides).

I honestly have no idea what to expect when you enable the device's IR
mode.  The ESC # command that gets sent to the scanner is not documented
in any of the 50+ ESC/I command specs that I have access to.

> Any way you would advise me getting my teeth into this. Debug
> settings, dump files to produce and look at. What part of the code
> should I start with rather than try and make sense of it all in one
> go?

Sorry I can't be of more help,
-- 
Olaf Meeuwissen, LPIC-2           FLOSS Engineer -- AVASYS CORPORATION
FSF Associate Member #1962               Help support software freedom
                 http://www.fsf.org/jf?referrer=1962