Re: touchscreen calibration again

Hi Lau,

Great work! I'm very please that you could achieve this level of accuracy!

> 2: End user calibration: An affine transformation is applied to the
> output of the linearization. This transformation will compensate for
> variation among individual IPaqs.

I hope this can be handled by the standard user calibration tools. We
will test this!

>
> A second order model is almost as good (3.7 and 2.2 pixels average
> errors), and practical experiments are neeed to determine if 3rd order
> is worth the extra CPU cycles:

Right! We will have to see, for example with an on-screen drawing
program. However, I don't think that 8 extra floating point
multiplications will be too hard to handle...

>
> These transformations should create points (a, b) in screen coordinates.
>
> If a more elaborate model is required, we will probably need an even
> better data set. It would be very interesting to see multiple
> "harvests" from the same IPaq. Then it would be possible to
> distinguish noise from "real" nonlineraity.

Good! I'll send you 1 or 2 more samples when I can. Other multiples from
other iPAQs are welcome, of course...

>
> Any volunteers for creating a test implementation in the driver?

I can take care of this.

This will also be a good way of testing the new 2.6.6 handhelds.org
kernel... I hope it doesn't break usb networking.

    Thanks again for everything!

    :-)

    Michael.

-- 
Michael Opdenacker
http://opdenacker.org/