[PD] HHT HilbertHuangTransform objects in Pd?

2010-11-15 Thread Ludwig Maes
I was wondering if somebody made HHT objects in Pd like:
[EMD x], splitting a signal in IMF (intrinsic mode) functions...?

How hard would it be to implement?

Greetings!

___
Pd-list@iem.at mailing list
UNSUBSCRIBE and account-management - 
http://lists.puredata.info/listinfo/pd-list


Re: [PD] HHT HilbertHuangTransform objects in Pd?

2010-11-15 Thread Mathieu Bouchard

On Mon, 15 Nov 2010, Charles Henry wrote:

However, there's an interesting and useful approximation given by the 
hilbert~.pd patch (provided in the extra directory perhaps?).  It uses 
two all-pass biquad filters that are ~90 degrees out of phase with each 
other to approximate the hilbert transform.


Unfortunately, there are two different things called Hilbert Transform, 
and the one with the two biquads doesn't approximate Hilbert's 
decomposition, they approximate the other thing called after Hilbert.

(is that right ?)

 ___
| Mathieu Bouchard  tél: +1.514.383.3801  Villeray, Montréal, QC
___
Pd-list@iem.at mailing list
UNSUBSCRIBE and account-management - 
http://lists.puredata.info/listinfo/pd-list


Re: [PD] HHT HilbertHuangTransform objects in Pd?

2010-11-15 Thread Mathieu Bouchard

On Mon, 15 Nov 2010, Mathieu Bouchard wrote:

Unfortunately, there are two different things called Hilbert Transform, 
and the one with the two biquads doesn't approximate Hilbert's 
decomposition, they approximate the other thing called after Hilbert. 
(is that right ?)


I probably got that wrong. I could swear I read something about such a 
confusion between two different things, but I can't find it now.


 ___
| Mathieu Bouchard  tél: +1.514.383.3801  Villeray, Montréal, QC
___
Pd-list@iem.at mailing list
UNSUBSCRIBE and account-management - 
http://lists.puredata.info/listinfo/pd-list


Re: [PD] HHT HilbertHuangTransform objects in Pd?

2010-11-15 Thread Charles Henry
On Mon, Nov 15, 2010 at 10:54 AM, Mathieu Bouchard ma...@artengine.cawrote:

 On Mon, 15 Nov 2010, Charles Henry wrote:

  However, there's an interesting and useful approximation given by the
 hilbert~.pd patch (provided in the extra directory perhaps?).  It uses two
 all-pass biquad filters that are ~90 degrees out of phase with each other to
 approximate the hilbert transform.


 Unfortunately, there are two different things called Hilbert Transform, and
 the one with the two biquads doesn't approximate Hilbert's decomposition,
 they approximate the other thing called after Hilbert.
 (is that right ?)


I don't know... The Hilbert transform on a function g(t) is this thing:
Hg = 1/pi * integral( s=-inf, inf ,   1/(t-s)*g(s) *ds)
or in other words, convolution by 1/(pi*t)

and there's a complex valued signal based on g(t)
h(t) = g(t) + i*Hg(t)

The Hilbert transform gives you just the imaginary part.  The hilbert~.pd
patch approximates this complex valued signal h(t).  I know there's a
reference to single-sideband modulation in the help patch if that's
related--is h(t) called the analytic signal?
___
Pd-list@iem.at mailing list
UNSUBSCRIBE and account-management - 
http://lists.puredata.info/listinfo/pd-list


Re: [PD] HHT HilbertHuangTransform objects in Pd?

2010-11-15 Thread Ludwig Maes
I even mean a third algorithm...
I am focused more the empirical mode decomposition put forward by
Huang, ... after splitting the signal in IMFs they are individually
analyzed by Hilbert transform, or other time frequency transform of
choice...
Im more looking to EMD, but I just found some matlab code which octave
seems to be able to run, and theres some C functions... going to look
how achievable it is, and going to ask permission from the author to
make Pd externals based on them...

___
Pd-list@iem.at mailing list
UNSUBSCRIBE and account-management - 
http://lists.puredata.info/listinfo/pd-list