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Antwort: Fast Fourier Transform: Location of Maxima

Posted by Joachim Wesner on Nov 02, 2009; 10:38am
URL: http://imagej.273.s1.nabble.com/Fast-Fourier-Transform-Location-of-Maxima-tp3690597p3690598.html

Hi Christian,

do you only want to find the location and intensity of the "1st order"
peak(s) (not counting the known zeroest order) or also want to get a
(probably sorted by intensity) list of all peaks?

In the former case, I have a plugin that uses this (it´s not a plugin on
it´s own) but it could be extended to a more general plugin and also to the
latter multi-peak case.

I do not know if there is already another independent plugin that already
does something similar. in my case a circular suppression area (of actually
~gaussian shape) is
applied on the zeroest order an the highest remeining peak is located (in
my case it makes no difference if it finds the +1 or -1 order because I
have real input data).

This is use for "fourier based" "spatial fringe demodulation" of
interferograms

This technique could be IMHO repeated to suppress the 1st order etc., the
extent of the suppression zone clearly would need to be optimzed to the
problem at hand.

You can contact me by PM if you like.

Mit freundlichen Grüßen / Best regards

Joachim Wesner



                                                                           
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Hi,

I am looking for a method to locate frequency maxima in the frequency
domain image yielded by FFT. The procedure should be reasonable fast since
large image stacks have to be processed.

Regards

Christian Kreutzfeldt



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