# Re: Document Feeders

Oliver Rauch (oliver.rauch@Wolfsburg.DE)
Tue, 27 Jul 1999 18:42:58 +0200

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Andreas Rick wrote:

> To add still more confusion to the ADF discussion I would like
> to add a small description of the automatic film strip feeder
> for the Nikon Filmscanners:
>
> When you put the film strip into the scanner
> (Strip of up to 6 24*36mm slides/negatives )
> the scanner does a very quick scan of the whole strip
> to find out and store the positions of all images.
> You can then query these positions and ask the Feeder to
> go to any position. There you can do anything you can do
> with a single slide: Preview, Scan, ...
> (it is the scanner head which moves while scanning not the film).
> There is a special command to eject the film.
> If you don't do anything the film is ejected after some
> minutes.
>
> With this kind of scanner I can imagine the following
> working scenarios:
>
> 1.) No Intervention:
> The user puts in the film and selects "ADF" and clicks
> on Scan. He/She should then find all the images on the disk/gimp.
>
> 2.) Personal selection
> The user puts in the film and clicks on "Preview all"
> which will scan all images in preview resolution.
> He/She may then select the preview images one by one,
> select the scanning area, the gamma, contrast etc.
> Finally by clicking on "scan" all selected image regions
> should be scanned
>
> I think the Nikon film scanner is more similar to the
> HP Flat Scanners in that the CCD moves during scanning, not the film.
>
> Do you think we can find a common way to access these different
> Feeders?

Hi Andreas,
the question is not if we will find a common way, the question is how.

You describe two different ways of scanning a film.

The one way is to scan like an adf and we should implement
this as an adf scan. So the user selects the source "ADF"
and the backend has to position the film to the next picture
if the frontend calls SANE_START.
This kind of scanning mode does not allow doing a preview.
So this kind of adf-scanning is for example to scan some
full pages - eg for copy or fax them or to archiev the full page/film.
The idea of ADF is put in your medias, press one button and
you have nothing more to do, it is all done by the machine.

For the second way you describe the backend has to make avaliable
functions like
- "next media",
- "previous media" although a normal
scanner is not able to reget an already scanned and unloaded paper
- "media number ##" - see above

This is not a real adf mode. I suggest to add a special source for this
like "Film feeder" or sth like that.

This is in each case a user interactive mode and has nothing to do with
ADF. So there will be no automatic functions in the frontend and
the frontend does not need to now these functions.

But we should define how some functions should be implemented.
This has nothing to do with the sane standard, but we could make
a document with suggestions how often used functions should be
implemented, so the user interface of different backends look not
too different.

Bye
Oliver

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