Re: Calibration algorithms

From: Henning Meier-Geinitz (henning@meier-geinitz.de)
Date: Mon May 21 2001 - 11:34:27 PDT

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    Hi,

    On Mon, May 21, 2001 at 12:13:04PM +1200, Glenn Ramsey wrote:
    > I guess the sm3600 backend also needs to use the dots and white
    > strip to do some sort of compensation.
    >
    > Does anyone have any references that discuss how this is done or
    > do any of the other backends have code that does this? Any help
    > would be greatly appreciated.

    Most Mustek scanners do automatic calibration. The Pro series needs
    has some sort of semi-automatic calibration. That means you must send
    a command to scan the strip (I call it "get_calibration_lines") and
    then send one line of correction data back to the scanner. I don't
    remember the exact algorithm but you can find it in the mustek.c code.
    It looks like the scanner uses the black point (it's more like a bar
    in my scanner) to set the black level and the white area to compensate
    for the different sensitiveness of the CCD sensor "points". The black
    bar is outside the normal scanning area in my scanner.

    Bye,
      Henning

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