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fft2drad

$ \bigcirc$Name


fft2drad compute average spectrum as a radial function




$ \bigcirc$Command Synopsis


fft2drad [-l] [-s size] [-I input_im] input_re out



-l : take log10

-s size : output size (number of cells), default min(nx,ny)

-I input_im : imaginary input (Fimage)

input_re : real input (Fimage)

out : output |  FFT |  =f(r) (Fsignal)




$ \bigcirc$Function Summary


Fsignal fft2drad (in_re , in_im , out , l_flag , size )

Fimage in_re , in_im ;

Fsignal out ;

char *l_flag ;

int *size ;




$ \bigcirc$Description


This module computes f (r), the average value of |$ \hat{u}$($ \xi$)| when |$ \xi$| = r. The discretization of the Fsignal f can be set manually with the -s option. Note that $ \xi$ is normalized in cycles per pixel, so that $ \hat{u}$ is defined on [- 1/2, 1/2]2 even for non-square images. Since f decreases very quickly, it is often better to take its logarithm (base 10) with the -l option.




$ \bigcirc$See Also


fft2dpol.




$ \bigcirc$Version 1.1


Last Modification date : Fri Jan 25 19:06:36 2002


$ \bigcirc$Author


Lionel Moisan






next up previous contents index
Next: fft2dview Up: Reference Previous: fft2dpol   Contents   Index
mw 2004-05-05