[RC,IC,Fx,Fy] = FOURIERTRANSFORM2(Z,dX,dY) Gives the components of the complex Fourier transform Cz(Fx,Fy) = RC(Fx,Fy) + i*IC(Fx,Fy) of a 2D real field Z(X,Y) taken at dX,dY sampling interval (optional), via FFT2 (fast).
The transform is symmetrical with respect to the origin because Z is real.
The spatial 2D Fourier frequencies Fx,Fy have the origin at the center. Fy (and Y) increase upwards contrary to the row index.
The user can see how to get the same result using FFT twice, or via complex exponentials (slower). This is the goal of the program.
The program comes with the example at the screenshot.
See also my fouriertransform.m here at FEx.
Inspired by: FourierTransform.m