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function G = createGabor(or, n)
%
% G = createGabor(numberOfOrientationsPerScale, n);
%
% Precomputes filter transfer functions. All computations are done on the
% Fourier domain.
%
% If you call this function without output arguments it will show the
% tiling of the Fourier domain.
%
% Input
% numberOfOrientationsPerScale = vector that contains the number of
% orientations at each scale (from HF to BF)
% n = imagesize (square images)
%
% output
% G = transfer functions for a jet of gabor filters
Nscales = length(or);
Nfilters = sum(or)
l=0;
for i=1:Nscales
for j=1:or(i)
l=l+1;
param(l,:)=[.35 .3/(1.85^(i-1)) 16*or(i)^2/32^2 pi/(or(i))*(j-1)];
end
end
% Frequencies:
[fx, fy] = meshgrid(-n/2:n/2-1);
fr = fftshift(sqrt(fx.^2+fy.^2));
t = fftshift(angle(fx+sqrt(-1)*fy));
% Transfer functions:
G=zeros([n n Nfilters]);
for i=1:Nfilters
par=param(i,:);
tr=t+param(i,4);
tr=tr+2*pi*(tr<-pi)-2*pi*(tr>pi);
G(:,:,i)=exp(-10*param(i,1)*(fr/n/param(i,2)-1).^2-2*param(i,3)*pi*tr.^2);
end
if nargout == 0
figure
for i=1:Nfilters
max(max(G(:,:,i)))
contour(fftshift(G(:,:,i)),[1 .7 .6],'r');
hold on
drawnow
end
axis('on')
axis('square')
axis('ij')
end
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