[sane-devel] SANE2 and filmscanners

[Jonathan Buzzard]

I have just taken a look at the SANE2 documentation, and a couple of 
things have struck me about lack of support for some features in
filmscanners.

The first is multipass scanning. Basically what happens here is that
the scanner can read the values several times and returns the averaged
result. This is useful for reducing noise from the A/D in the image
data. Sometimes you can simulate this by making multiple passes and
averaging the images, though it is not as good as it leads to a slight
loss in resolution.

Batch scanning is the other. Here you might have a film or slide holder
that has several separate images (or even an APS adaptor) and you
just want to click a button to scan the lot. You need some way to
communicate to the front end just how many images there are to scan
etc. You also possibly need some way to allow the front end to pick
an individual image to scan.

Focusing, although most units are now autofocus, you can often override
this for manual focusing if you want. I see no support of this in the
proposed standard.

I presume that a fourth infra-red channel would also be supported but can
not see anything about it in the documentation.

JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan at buzzard.org.uk
Northumberland, United Kingdom.       Tel: +44(0)1661-832195