On Fri, 16 Apr 2004 16:21:51 +0200
Alain2210 <alain2210_at_free.fr> wrote:
> For better understanding the value given by the touchscreen. I have got the
> raw values when the pen follows the borders of the screen.
> It gives this :
> http://alain2210.free.fr/geombrut.pdf
Pretty sad. Until now I have assumed all touchscreens have a linear response,
but now I see that at least h22xx doesn't. I don't know yet how a general
transform equation should look like, but it will have to be more complex than
just multiplying an 1x2 vector by a 2x2 matrix.
How the calibration process should look like? Does it make sense to
display something like "Please follow with the pen the borders of the screen
in the following order: top-left - top-right - bottom-right - bottom-left -
top-left"? Maybe this calibration process will be even easier to accomplish
than clicking four or five screen points. Perhaps a final step would be to
click the central screen point in order to detect non-linearity within the
touchscreen values area. Oh.
-- Greetings, AndrewReceived on Sat Apr 17 2004 - 07:09:19 EDT
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