ifft2

Purpose

Inverse 2-D fast Fourier transform.

Synopsis

Y = ifft2(X)
Y = ifft2(X,m,n)

Description

ifft2(X) returns the two-dimensional inverse fast Fourier transform of matrix X.

ifft(X,m,n) returns the m-by-n inverse transform.

Examples

For any X, ifft2(fft2(X)) equals X to within roundoff error. If X is real, ifft2(fft2(X)) may have small imaginary parts.

Algorithm

The algorithm for ifft2(X) is the same as the algorithm for fft2(X), except for a sign change and scale factors of [m,n] = size(X). The execution time is fastest when m and n are powers of 2 and slowest when they are large primes.

See Also

fft, fft2, fftshift,  filter, ifft
dftmtx, freqz, specplot, and spectrum in the Signal Processing Toolbox

(c) Copyright 1994 by The MathWorks, Inc.