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Re: 1D Fourier transform in macro

Posted by Ludovic Pinier on Oct 06, 2014; 7:07am
URL: http://imagej.273.s1.nabble.com/1D-Fourier-transform-in-macro-tp5009727p5009909.html

Good morning,

Thanks a lot for this news.
I will try this new macro asap.

Best regards,
Ludovic


-----Original Message-----
From: ImageJ Interest Group [mailto:[hidden email]] On Behalf Of Herbie
Sent: Montag, 29. September 2014 12:30
To: [hidden email]
Subject: Re: 1D Fourier transform in macro

Good day Michael and Wayne,

the IJ-macro routine Array.fourier(...) is good news, but why not optionally output the complex-valued 1D Fourier transform?

One may add a third parameter that, if not present, will result in the magnitude of the 1D Fourier transform. Otherwise the parameter indicates that the complex-valued 1D Fourier transform (real & imaginary, or magnitude & phase) is to be returned.

A possible array format for the transform is discussed in "Numerical Recipes". It is based on the fact that the first and last imaginary values are known to be zero and therefore need not be stored in the array.

Just a suggestion...

Best regards

Herbie

::::::::::::::::::::::::::::::::::::::::
On 28.09.14 21:12, Michael Schmid wrote:

> Hi Ludovic,
>
> in the latest daily build, Wayne has added an Array.fourier(theArray,
> windowType) macro function, based on code snippets that I have sent to
> him. Use Help>Update ImageJ to obtain the daily build.
>
> There is some documentation and a text macro for the new function at
>
> http://imagej.nih.gov/ij/macros/examples/TestArrayFourier.txt
>
> In your case, with data values approaching (or equel to) zero at the
> beginning and end of the array, you don't need a window function;
> simply omit that parameter or write "none" (with the quotes!) for the windowType.
>
> Michael
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html

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