Re: Macros to read and write Complex Fourier Transform

Posted by Michael Schmid on Feb 13, 2009; 10:33am
URL: http://imagej.273.s1.nabble.com/Macros-to-read-and-write-Complex-Fourier-Transform-tp3693680p3693691.html

Hi,

you can use Process>FFT>FFT Options in standard ImageJ (no Fiji  
required) to access the real and imaginary parts of the FFT.
I have not checked whether they are mathematically correct, but at  
least they are consistent with the power spectrum that you get from  
FFT Options, i.e.

real^2 + imaaginary^2 = power spectrum

Michael
________________________________________________________________

On 13 Feb 2009, at 03:24, Johannes Schindelin wrote:

> Hi,
>
> On Fri, 23 Jan 2009, Marco LO wrote:
>
>> What is the data format of Complex Fourier Transform in FFT?  Is  
>> there
>> any macro to read and write the Real and Imaginary transformation  
>> from
>> and to a file so that I could manipulate the data directly.
>
> <shameless plug>
> If you use Fiji (http://pacific.mpi-cbg.de/), you will have a  
> choice of
> scripting languages with which to access the image data, and you  
> will also
> have a pretty fast pure Java FFT bundled:
> http://boole.mines.edu/doc/api/edu/mines/jtk/dsp/FftComplex.html
> </shameless>
>
> There is no complex fast Fourier transform in ImageJ, as far as I can
> tell.
>
> Ciao,
> Dscho