Y = fft2(X)
Y = fft2(X,m,n)
Y = fft2(X)
performs the two-dimensional FFT. The result Y
is the same size as X.
Y = fft2(X,m,n)
either truncates X
or pads X
with 0s to create an m
-by-n
array before doing the transform. The result is m
-by-n
.
fft2(X)
is simply
fft(fft(X).').'
This computes the one-dimensional FFT of each column X
, then of each row of the result. The time required to compute fft2(X)
depends strongly on the number of prime factors in [m,n] = size(X)
. It is fastest when m
and n
are powers of 2.
fft
, fftshift
, ifft2
(c) Copyright 1994 by The MathWorks, Inc.