> Oliver Rauch (oliver.rauch@Wolfsburg.DE) wrote:
> > that is the reason why I renamed it!
> > The frontend does not need to know how the alpha channel
> > is generated, so it is better to name it alpha than infrared.
>
> I feel it's a bit stupid and confusing to call it the alpha channel.
> Alpha channel has a very well defined and established meaning in the
> graphics world. Just because you can dump the infrared data into the
> 4th channel of a file doesn't make this data 'alpha' in any way. If
> you look at the SANE standard, it defines the red channel as 'data
> from the red spectral band', etc. , so why would the infrared channel
> be treated differently.
>
> Should scanners in the future support a different sort of 4th channel,
> lets say height, then it should get it's own SANE_FRAME name (eg RGBH
> or something).
>
> The SANE_FRAME name tells the frontend what sort of data it is that it
> receives. Perhaps your frontend isn't interested in this but other
> frontends might.
>
>
Hi Ewald,
the idea of the infrared-channel of the slide scanners is comparable
to the alpha channel. It is to detect dust and things like that to
identify the transparency of the slide.
Of course we could add an IR and an UV channel and thousands of other
channels, but then somone should go and define image file formats that do
suppurt such data.
Bye
Oliver
-- EMAIL: Oliver.Rauch@Wolfsburg.DE WWW: http://www.wolfsburg.de/~rauch
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