fft2
Two Dimensionl Fast Fourier Transform
(y)=fft2(x)
Inputs
x A two dimensional array of real or complex numbers.
Outputs
y A two dimensional array of complex numbers.


Description
The output of fft2 is the Fast Fourier Transform of the input. Prior to the computation of the transform, the input is padded with sufficient number of rows and columns with zeros so that both the row size and the column size of the array are powers of 2.

The FFT of a two-dimensional array is computed by two stages: (a) first a matrix is computed such that each of its columns is the FFT of the corresponding column of the (appropriated padded, if necessary) input, and then (b) a matrix is computed such that each of its rows is the FFT of the corresponding row of the matrix computed in the first step.