[sane-devel] Infrared channel

[Michal Jaegermann]

On Tue, Feb 22, 2005 at 08:28:18AM +0100, Gerhard Jaeger wrote:
> On Monday 21 February 2005 00:09, Michal Jaegermann wrote:
> > 
> > But does somebody at least have some idea how to read an infrared
> > channel?
> 
> the problem is our SANE 1 standard, which defines the image format.
> We have currently only the possibility to pass RGB data to a frontend.

Still coolscan2 driver somehow manages in that framework for years.
Yes, I understand that this is hacky (ab)use of Alpha channel but
the point is that one can retrieve an available information.  xsane
has even some options to help with this.

> The solution (whenever we can start) is SANE 2 where we have a more flexible
> approach for transmitting image data to a frontend.

I am all for a better standard which would be a right fit for the
current technology and would allow to use it without strange
contortions.  The problem is that I have seen in archives messages
from a year 2002 talking about SANE 2, and they were not likely the
earliest ones, so with the current pace this sounds like a really
long term project.  In the meantime I have some scanners to use now.
This is somewhat discouraging.

I am glad that at least apparently I provoked some discussion. :-)

> It might also be possible for a backend to read the infrared channel and to
> perform i.e. the dust removal in the backend, but this functionality should
> in general be part of a frontend.

I do not suggest now that dust removal should be folded into a
backend (or any other particular place).  Still from what I
understand the prerequisite is that one has to get somehow out
of scanner relevant data.  I am not above writing some code but
I am afraid that I have not a clue how to talk to a scanner to
convince it to send me that stuff.  If such documentation exists
then I failed to find it in my Google searches.

> VueScans' advantage or disadvantage here is, that you have a all-in-one
> program (scanner-driver + image processor), this has never been the
> approach of SANE...

I do not mind a stand-alone dust remover program.  It looks that
with a bit of scripting one should be able to automate such tasks in
any case.  Although some hooks in right places which would allow to
drop some external filters into a data stream would be really handy.
In a general picture these things look like details.

   Thanks,
   Michal