Re: problems with snapscan and scanimage

charter@cs.ualberta.ca
Mon, 11 May 1998 21:42:28 -0600 (MDT)

>
>
> On Mon, 11 May 1998, KH Jeron wrote:
>
> --- ../../sane-pre0.72.org/backend/snapscan.c Fri Apr 3 11:14:09 1998
> +++ snapscan.c Sun Apr 5 20:47:10 1998
> @@ -2594,7 +2594,7 @@
> for black and white */
> p->depth = pss->pdev->depths[mode];
>
> - if (pss->preview && p->depth > 8)
> + if (/* pss->preview && */ p->depth > 8)
> p->depth = 8;
>
> switch (mode)
>
>
> This may be diffed from a slightly hacked version of snapscan.c, but
> you get the point -- force depth to never be more than eight bits...
>

Yes, this should do the trick.

> (*) After a closer look I'd say it does not produce 10 bits -- it just
> *claims* to :-)

The output from the scanner to the host is 8 bits per sample, but the
scanner allows the host to download a 10-bit gamma table for each
channel. Presumably this gives finer control over gamma correction (or
"tone curving") than the 8-bit tables, despite the fact that the data
is being converted to 8 bits before it's sent to the host.

other scanner models too.

Kevin

-- 
Kevin Charter                        /\                      Grad Studies
charter@cs.ualberta.ca            /\/  \  Department of Computing Science
http://web.cs.ualberta.ca/~charter  \   --------    University of Alberta
	       		             --------------    Edmonton AB CANADA



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