Re: RGBI (was Re: xsane-0.31 available)

Nick Lamb (njl98r@ecs.soton.ac.uk)
Tue, 3 Aug 1999 21:45:48 +0100 (GMT)

Oliver, please use a mail client which can do proper line wrap, it is
getting annoying to keep reformatting your text so that it is readable
in the replies.

On Tue, 3 Aug 1999, Oliver Rauch wrote:
> It is not good to add one format that does not make sense. So we should
> not wait until we have 5 bad formats.
>
> I don`t say that we should not add SANE_FRAME_INFRARED or RGBI.
> I only say it does not make any sense if we do not define how to save
> and handle them.
>
> As long as there is no file format for RGBIr and another one for RGBUv
> and we have to handle it the same way and ony the user knows the difference,
> why should we add two different formats for this.

Stop obsessing over file formats Oliver. If all you are going to do is
save it as a JPEG and put it on the web, then just don't choose "Infrared
mode" from the Coolscan backend.

To handle RGBI you should apply a filter which can compensate for the
scratches, prints, dust etc. revealed on the Infrared channel. You also
need to compensate for the leakage between RED and IR detection.

If a frontend doesn't have such a filter, it has two choices -- it can
refuse to handle the unknown FRAME type, or it could send the data for
post-processing in another application. I really DO NOT CARE whether
XSane can handle this, or not -- just so long as SANE makes it possible
for someone to write a SANE-compliant application which does it.

Understand me here Oliver -- this is not about adding features to
XSane, or not adding them, it is about supporting the Coolscan in SANE

I want to call these frames RGBI because that is what they are. There
are no backends which will support "alpha" data or "height" data or
any other kind of extra data, but there IS a backend which creates
"infrared" data, so I want a frame format for it.

I can't see any reason why XSane shouldn't _save_ RGBI data into RGBA
file formats for use in another application, but that's no reason not
to call the data "RGBI" when it is sent from SANE to my imaginary RGBI
capable film-scanner frontend.

Finally, since you're so interested, I suspect you could use the
additional channels sense in TIFF to support saving files with IR
data, and most good import filters would do something sensible (ie
not treat it as alpha) when you load it. Exporting properly to Gimp
would be nice too.

Nick.

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