[scilab-Users] Loglog plot and fft2

[Samuel GOUGEON]

  ----- Message d'origine -----
De : Paolo Zaffino
Date : 07/03/2011 20:38:
> First of all thanks for the reply!
> No, I'd like plot into a 2d graph each spatial frequency vs its magnitude.
> An average of two spatial frequencies would be fine...but I don't know how I 
> can do it.
You can average  the signal _before_ the FFT : See sum(..., "r") or sum(.., "c")
You can average the FFT magnitude along lines or columns.
It depends on what you are searching for. This is your job.

Then, to get a loglog plot you will have to remove the 0-frequency
(= average of the signal), and frequencies with null magnitudes
(if any).

Finally, the graphics will be something like: plot2d("ll",frequencies, magnitudes)

Regards
Samuel

PS : This is mostly some signal processing stuff rather than some Scilab one.