function [K]=fourier(I)
[nblig , nbcol] = size(I);
K=zeros(nblig,nbcol);
for u = 1 : nblig
      for v = 1 : nbcol
      	som=0;
		for l = 1 : nblig
      			for c = 1 : nbcol
				som=som+I(l,c)*exp(-2*%i*%pi*(((u*l)/nblig)+((v*c)/nbcol)));		
end;
end;
K(u,v)=som;
end;
end;      
endfunction;

