[PD] is there a kalman filter for pd? (if not I could probably provide one, if I make it :) )

[Pedro Lopes]

Got it working, but just realized that some of you need a 1D kalman,
and I was working on a 2D kalman. A cool version could accept params
[kalman <dim> <other params>]

Nothing works within pd yet, but lets see if I have time for that. I
will also play around with some 1D implementations.

best,
p

On Fri, Dec 14, 2012 at 2:06 PM, katja <katjavetter at gmail.com> wrote:
> Thanks for the suggestion, Cyrille. I've been playing around with
> median filters in a different context (spectral processing), but
> completely forgot about them.
>
> With the variometer, the problem is to isolate very low frequencies
> (the pressure gradient you want to detect) from DC (constant
> atmospheric pressure at certain height) and sensor noise frequencies.
> And you want to see results with accuracy and little delay. In fact it
> needs a very sharp minimum-phase filter. Maybe a median filter can
> 'preprocess' the signal in some way. Anyway it gives a new
> perspective.
>
> Katja
>
>
>
> On Fri, Dec 14, 2012 at 1:27 PM, Cyrille Henry <ch at chnry.net> wrote:
>> for sensors data, depending of the noise, it can be useful to begin with a
>> median filter.
>> a median on the 7 last sample add 3 sample delay, but often remove lot's of
>> noise.
>>
>> you can find them in mapping or puremapping libs.
>> cheers
>> cyrille
>>
>>
>> Le 14/12/2012 11:38, katja a écrit :
>>
>>> Patrick, the barometer sensor samplerate is ~50 Hz and I did the
>>> butterworth filter with regular Pd objects, not as external (see
>>> attached).
>>>
>>> In the Pd patch I modeled sensor noise (resolution 3 Pascal according
>>> to datasheet) and pressure gradient, simulating vertical speed through
>>> the air. The aim is to get 0.1 m/s accuracy in vertical speed reading.
>>> Theoretically, this would be almost possible with the butterworth. But
>>> our real sensor has much more noise than 3 Pascal resolution.
>>> Therefore I'm still interested in better filters.
>>>
>>> Katja
>>>
>>>
>>> On Wed, Dec 12, 2012 at 6:29 PM, patrick <puredata at 11h11.com> wrote:
>>>>
>>>> hi Katja,
>>>>
>>>> did you ported this filter:
>>>> https://github.com/lebipbip/le-BipBip/blob/master/filter.c
>>>>
>>>> to an pd external? if yes could you share it? not sure if it would help
>>>> my
>>>> situation (noisy accelerometer 1 axis), but i would like to give it a
>>>> shot.
>>>>
>>>> thx
>>>>
>>>>
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-- 
Pedro Lopes (HCI Researcher / MSc)
contact: pedro.lopes at ist.utl.pt
website: http://web.ist.utl.pt/pedro.lopes /
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