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Please note that the recommended version of Scilab is 2025.0.0. This page might be outdated.
See the recommended documentation of this function
fft2
two-dimension fast Fourier transform
Calling Sequence
y=fft2(x) y=fft2(x,n,m)
Arguments
- x
a vector/matrix/array (Real or Complex)
- y
a vector/matrix/array (Real or Complex)
- m
integer, number of rows.
- n
integer, number of columns.
Description
This functions performs the two-dimension discrete Fourier transform.
y=fft2(x)
y and x have the same size
y=fft2(x,m,n):
If m
(respectively
n
) is less than the rows number (respectively columns) of
x
then the x
rows number (resp. columns) is
truncated, else if m (resp. n
) is more than the rows number
(resp. columns) of x
then x
rows are completed
by zero (resp. columns) .
if x
is a matrix then y
is a matrix, if
x
is a hypermatrix then y
is a hypermatrix, with
the size of the first dimension of y
is equal to
m
, the size of the second dimension of y
is
equal to n
, the size of the ith dimension of y
(for i>2, case hypermatrix) equal to the size of the ith dimension of
x
. (i.e size(y,1)=m, size(y,2)=n and size(y,i)=size(x,i) for
i>2)
Examples
//Comparison with explicit formula a=[1 2 3 ;4 5 6 ;7 8 9 ;10 11 12] m=size(a,1) n=size(a,2) // fourier transform along the rows for i=1:n a1(:,i)=exp(-2*%i*%pi*(0:m-1)'.*.(0:m-1)/m)*a(:,i) end // fourier transform along the columns for j=1:m a2temp=exp(-2*%i*%pi*(0:n-1)'.*.(0:n-1)/n)*(a1(j,:)).' a2(j,:)=a2temp.' end norm(a2-fft2(a))
See Also
- fft — fast Fourier transform.
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