## [SOLVED] PRobem of deconvolution...

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no, scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Hello,\n\nI am trying to model the behaviour of a reactor vessel when some\nparticles inside the container strike the inner wall using FINITE\nELEMENT MODELLING software.\n\nI reproduced several random particles hitting the wall at different\ntimes and position across the surface of the inside wall.\n\nNow I would like to get rid of the TRANSFER FUNCTION of the container\nfrom the random particles data using the deconvolution to extract only\nthe particle informations.\n\nI apply an inpulse inside the vessel (the middle) and I acquire the\noutput on the outer surface.\n\nTHe PROBLEM: How can I deconvolve the spectra in a right way?\nIn fact the TRANSFER FUNCTION of the vessel changes according with the\nposition of the impact.\n\nThe tranfer function of the vessel will be completely different when\nconsidering the position A or position B.\n\n\n| |\nposB&gt; | |\n| |\nposA&gt; | |&gt; output\n| |\n| |\n\n\n\n\n\n\nCan somebody help me please?\nWhat kind of DSP tool should I use?\nit is really important for me to solve this problem.\n\nThanks a lot\nM\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>Hello,

I am trying to model the behaviour of a reactor vessel when some
particles inside the container strike the inner wall using FINITE
ELEMENT MODELLING software.

I reproduced several random particles hitting the wall at different
times and position across the surface of the inside wall.

Now I would like to get rid of the TRANSFER FUNCTION of the container
from the random particles data using the deconvolution to extract only
the particle informations.

I apply an inpulse inside the vessel (the middle) and I acquire the
output on the outer surface.

THe PROBLEM: How can I deconvolve the spectra in a right way?
In fact the TRANSFER FUNCTION of the vessel changes according with the
position of the impact.

The tranfer function of the vessel will be completely different when
considering the position A or position B.

| |
posB> | |
| |
posA> $| |>$ output
| |
| |

Can somebody help me please?
What kind of DSP tool should I use?
it is really important for me to solve this problem.

Thanks a lot
M

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It looks like deterministic deconvolution will be difficult to implement. I would try minimum phase deconvolution as used in seismic exploration geophysics. If you know the input response is a spike, this should work well. The method works by deriving a causal impulse response with minimum length that has the same autocorrelation as the data. An inverse to this response is computed and convolved with the data. John Reed "tramoman" wrote in message news:1120147191.515447.136680@g43g20...egroups.com... > Hello, > > I am trying to model the behaviour of a reactor vessel when some > particles inside the container strike the inner wall using FINITE > ELEMENT MODELLING software. > > I reproduced several random particles hitting the wall at different > times and position across the surface of the inside wall. > > Now I would like to get rid of the TRANSFER FUNCTION of the container > from the random particles data using the deconvolution to extract only > the particle informations. > > I apply an inpulse inside the vessel (the middle) and I acquire the > output on the outer surface. > > THe PROBLEM: How can I deconvolve the spectra in a right way? > In fact the TRANSFER FUNCTION of the vessel changes according with the > position of the impact. > > The tranfer function of the vessel will be completely different when > considering the position A or position B. > > > | | > posB> | | > | | > posA> $| |>$ output > | | > | |



John, I spoke to 3 DPS professors and none of them were able to give me this kind of information. This is the last chance and the only good idea. I have tried to search for "minimum phase deconvolution " but I could not really find something easy to understand. Can you please suggest me if this techique has another name or give more details? the input response has a shape of an Hamming window with different bandwidths and amplitudes between $(200khz-40Mhz)$ and $(0.8-1).$ They are random distributed across the inner surface of the vessel. The aim is to get the acoustic signature of the vessel and figure out more information about the particles. Could the minimum phase deconvolution fit for my problem? Thanks a lot for your courtesy. M

## [SOLVED] PRobem of deconvolution...

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no, scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\nJohn Reed wrote:\n&gt; It looks like deterministic deconvolution will be difficult to implement. I\n&gt; would try minimum phase deconvolution as used in seismic exploration\n&gt; geophysics. If you know the input response is a spike, this should work\n&gt; well. The method works by deriving a causal impulse response with minimum\n&gt; length that has the same autocorrelation as the data. An inverse to this\n&gt; response is computed and convolved with the data.\n&gt;\n&gt; John Reed\n&gt; &gt; &gt; | |\n\nJohn,\nI spoke to 3 DPS professors and none of them were able to give me this\nkind of information. This is the last chance and the only good idea.\nI have tried to search for "minimum phase deconvolution " but I could\nnot really find something easy to understand. Can you please suggest me\nif this techique has another name or give more details?\n\nthe input response has a shape of an Hamming window with different\nbandwidths and amplitudes between (200khz-40Mhz) and (0.8-1). They are\nrandom distributed across the inner surface of the vessel. The aim is\nto get the acoustic signature of the vessel and figure out more\ninformation about the particles. Could the minimum phase deconvolution\nfit for my problem? Thanks a lot for your courtesy.\n&gt;\ntramoman\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>John Reed wrote:
> It looks like deterministic deconvolution will be difficult to implement. I
> would try minimum phase deconvolution as used in seismic exploration
> geophysics. If you know the input response is a spike, this should work
> well. The method works by deriving a causal impulse response with minimum
> length that has the same autocorrelation as the data. An inverse to this
> response is computed and convolved with the data.
>
> John Reed
> > > | |

John,
I spoke to 3 DPS professors and none of them were able to give me this
kind of information. This is the last chance and the only good idea.
I have tried to search for "minimum phase deconvolution " but I could
not really find something easy to understand. Can you please suggest me
if this techique has another name or give more details?

the input response has a shape of an Hamming window with different
bandwidths and amplitudes between $(200khz-40Mhz)$ and $(0.8-1).$ They are
random distributed across the inner surface of the vessel. The aim is
to get the acoustic signature of the vessel and figure out more
information about the particles. Could the minimum phase deconvolution
fit for my problem? Thanks a lot for your courtesy.
>

tramoman

 Quote by tramoman I am trying to model the behaviour of a reactor vessel when some particles inside the container strike the inner wall using FINITE ELEMENT MODELLING software. I reproduced several random particles hitting the wall at different times and position across the surface of the inside wall. Now I would like to get rid of the TRANSFER FUNCTION of the container from the random particles data using the deconvolution to extract only the particle informations. I apply an inpulse inside the vessel (the middle) and I acquire the output on the outer surface. THe PROBLEM: How can I deconvolve the spectra in a right way? In fact the TRANSFER FUNCTION of the vessel changes according with the position of the impact. The tranfer function of the vessel will be completely different when considering the position A or position B. | | posB> | | | | posA> $| |>$ output | | | | Can somebody help me please? What kind of DSP tool should I use? it is really important for me to solve this problem. Thanks a lot M
Do you know the transfer function?If yes, I think dividing your data by an averaged form of it should do.Else,if you can assume that the collisions are completely random(white spectrum) and the impulse response of the vessel 'minimum phase' ---find the power spectrum from autocorrelation of data(so that you have the amplitude spectrum).Phase spectrum can then be uniquely found(for 'minimum phase' wavelets)--for the formula see any DSP book or Jon F. Claerbout's book on geophysical signal processing.
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