[sane-devel] Ideas Wanted [Acer ScanWit]

[Henning Meier-Geinitz]

Hi,

On Sun, Feb 03, 2002 at 12:11:28PM +0300, Max Ushakov wrote:
> The ``strange part'' 6 looks like this:
> 
>    READ with DT=0x80 and DTQ=0, 61056 bytes
>    READ with DT=0x80 and DTQ=0, 0 bytes
> 
>    READ with DT=0x82 and DTQ=0x10, 7650 bytes
>    (repeats 15 times)
>    SEND with DT=0x82 and DTQ=0x01, 7650 bytes
> 
> The data sent and received had little meaning to me -- it
> contained a block of bytes near to 0xff in one place and a block
> of bytes near to 0x3c in another.
> 
> What could this be?

Maybe some sort of calibration? The Mustek flatbed scanners do a
similar thing. First scan some lines of a (mostly) white strip and
send it to the driver. The driver then calculates a value describing
the loss/gain for every ccd sensor element to compensate for slight
differences in the sensitivity of these elements.

There is also a black stripe at the begiining of the white stripe (ca
3mm), which is for calibrating the black point.

Bye,
  Henning