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### Highlights fromHow to use FFT2

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# How to use FFT2

05 Jul 2006 (Updated 05 Jul 2006)

How to apply the 2D FFT functions in Matlab

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The note explains in detail how to apply the Matlab 2-dimensional FFT for filtering of two-dimensional signals, e.g. images.
It is shown how to connect the output from fft2 to the actual Fourier transform of the signal, and in particular how transfer functions of simple filters may be coded.

MATLAB release MATLAB 7.1.0 (R14SP3)
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23 Apr 2008
28 Jan 2008

I applied it as follows:

%****FFT Low Pass Filter****%
%Array dimensions
M = 1024;
N = 1024;
%Sampling intervals
dx = 1;
dy = 1;
%Characteristic wavelengths
KX0 = (mod(1/2 + (0:(M-1))/M , 1) - 1/2);
KX1 = KX0 * (2*pi/dx);
KY0 = (mod(1/2 + (0:(N-1))/N , 1) - 1/2);
KY1 = KY0 * (2*pi/dx);
[KX,KY] = meshgrid(KX1,KY1);
%Filter formulation
K0 = 0.16;
T = (KX.*KX + KY.*KY < K0^2);
%Filter Application
bwmofilt = ifft2(T.*fft2(bwmo));
imwrite(bwmofilt,'4.filtered.jpg');
%******END of FFT Low Pass Filter******%

28 Jan 2008

18 Jan 2008
29 Mar 2007

good

28 Jan 2007

helping material

03 Jan 2007
18 Jul 2006

A good material...

06 Jul 2006
05 Jul 2006

since this PDF submission does not provide any usable code it should be tagged as a WHITE PAPER
us