Re: Slide Scanners

[Bastien Nocera <hadess hadess net>]

Hey,

On Mon, 2017-10-02 at 21:26 +0100, ChrisOfBristol wrote:
> There doesn't seem to be any Linux provision for slide scanners. There 
> is also some confusion because they are not really scanners - they don't 
> scan, so using normal scanning software won't work. In fact they take a 
> photo, which means that Cheese would be a good application to use for them.

You're confusing the method of access ("it shows up as a webcam") and
which application you should be using to use it.

I would expect Simple Scan to implement this, not Cheese, as you would
probably want similar photo manipulation functionality for flat-bed
scanners with negative and slide inserts.

> Cheese does work with my Maginon FS500, but it only offers a much lower 
> resolution than my slide scanner is capable of. It would be a very 
> useful expansion of the use of Cheese if this could be fixed.

Probably because the view you get in Cheese is the preview. There's an
extension to the USB Video Camera specification which allows taking
pictures, which neither Cheese nor GStreamer, or the kernel currently
support.

A version of this was implemented here, for a pretty old kernel:
https://github.com/yangh/uvcvideo

I would expect the functionality to go something like:
- Implement Still Image support in the kernel
- Add support for it in GStreamer
- Mark Still Image devices as being either a scanner or a webcam
- Add support for Simple Scan and Cheese to use still image capture (so
it works out of the box in Simple Scan for slide scanners like yours,
and Cheese can capture higher quality stills)

Cheers