Image Processing Toolbox

fftn

Compute N-dimensional fast Fourier transform

Syntax

B = fftn(A)
B = fftn(A,siz)

Description

B = fftn(A) performs the N-dimensional fast Fourier transform. The result B is the same size as A.

B = fftn(A,siz) pads A with zeros (or truncates A) to create an N-dimensional array of size siz before doing the transform. The size of the result is siz.

Class Support

The input matrix A can be of class double or of any integer class. The output matrix B is of class double.

Remarks

fftn is a function in MATLAB.

Algorithm

fftn(A) is equivalent to:

B = A;
for p = 1:length(size(A))
    B = fft(B,[],p);
end

This code computes the one-dimensional fast Fourier transform along each dimension of A. The time required to compute fftn(A) depends strongly on the number of prime factors of the dimensions of A. It is fastest when all of the dimensions are powers of 2.

See Also

fft2, ifftn

fft in the MATLAB Function Reference

fft2

fftshift