nanogui: touchscreen calibration
Subject:
Re: [nanogui] Touchscreen calibration
From:
Daniel Csabai ####@####.####
Date:
16 Mar 2004 09:00:50 +0000
Message-Id: <4056C2C0.1080509@e77.hu>
Hello Mark,
this program is a fine application. I will use some std. function from
microwindows to use this transform.
But, I am going to use some more different algorithm to calculate the
coefficients by three points.
A link about the calibration:
http://www.embedded.com/story/OEG20020529S0046
Thanks,
Daniel
> Hello Daniel,
>
> I did some more searching in Microwindows and found a nice example
> called nxcal.c. This program calculates a transform which is also
> used in GdMouseRead to filter jitter. We used nxcal.c as a starting
> point and came up with a nice calibration and filter for our touchscreen.
>
> Thanks,
>
> Mark
>
> At 01:03 PM 3/9/2004 +0100, you wrote:
>
>> Hello Mark,
>>
>>
>> Mark Mussetter írta:
>>
>>> Hello Everyone,
>>>
>>> We have a 240X320 touchscreen display basically working with
>>> FLTK1.1.4 and Microwindows-0.90. We calibrated the touchscreen by
>>> hand using equations that take into account the ADC ranges of the
>>> X-axis and Y-axis. This gets us pretty close on our coordinate
>>> calculations, however, we were wondering if there is a standard way
>>> of doing touchscreen calibration with Microwindows so we don't have
>>> to repeat this procedure for every new screen we install.
>>
>> I am working also on calibration problem. I have not find any
>> standard routine. That is the case I am going to write one! I have a
>> sample program that I can send to you that maybe can partly help.
>>
>>> Is there a standard calibration routine included in Microwindows and
>>> do you feed it raw ADC values?
>>>
>>> Also, we are getting coordinate readings back that vary by about +/-
>>> 10 pixels of the actual "pen down" location. Are there any
>>> filtering routines out there that filter out that noise and maybe
>>> debounce the "pen down" readings?
>>
>>
>> I found an old microwindows driver at this distribution at the
>> src/drivers/old/mou_tp.c. In the "first"PD_Read(...) function you
>> can find codes that filter the noises after the conversation process.
>> I implemented this one and I got more stable cursor.
>>
>> Regards,
>> Daniel
>>
>>>
>>> Thanks for any help you could give,
>>>
>>> Mark
>>>
>>> Our system:
>>> Motorola 5272
>>> RTEMS 4.6.0pre5
>>> FLTK1.1.4
>>> nxlib0.44
>>> Microwindows-0.90
>>>
>>>
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>>
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