[sane-devel] Progress on CanoScan D1250U2

[Norbert LATAILLE]

Hi,

I started to work on the D1250U2 scanner some time ago, and I now 
starting to have a standalone program (using libusb) which is producing 
scanned BMP files under linux (24-bit mode, 75 dpi for now).

However, something still confuses me about the color managment of this 
scanner. Except from extra lines produced by the scanner, I have got 6 
times more bytes than the number of pixels in the image. At first I 
said: "fine, this is a 48-bit scanner after all". In fact it is producing:

RGB RGB RGB RGB ... RGB [line0]
RGB RGB RGB RGB ... RGB [line0-bis]
RGB RGB RGB RGB ... RGB [line1]
RGB RGB RGB RGB ... RGB [line1-bis]
...
RGB RGB RGB RGB ... RGB [lastline]
RGB RGB RGB RGB ... RGB [lastline-bis]

Where [line0-bis] is somewhat different from [line0], and also different 
  from the TWAIN output. I really seems like the scanner is doing its 
job in 75dpix150dpi leaving to me the job of merging lines (but this 
would not be 48-bits scanning). I believe that we will get more clues 
when moving to another resolution.

Here is my question: what is the standard output of a 48-bit scanner in 
other drivers ? LSB/MSB bytes ? 2 lines ?

Another question is: what minimal features are expected by sane ? at 
least choosing scanning resolution ? choosing color mode ? setting 
shading data ?

Regards,

Norbert