www.pudn.com > gaborfilter.rar > gaborfilter2.m

%%%%%%%VERSION 3 
%%ANOTHER DESCRIBTION OF GABOR FILTER 
 
%The Gabor filter is basically a Gaussian (with variances sx and sy along x and y-axes respectively) 
%modulated by a complex sinusoid (with centre frequencies U and V along x and y-axes respectively)  
%described by the following equation 
%% 
%               1                -1     x  ^    y  ^ 
%%% Gi(x,y) = ---------- * exp ([----{(----) 2+(----) 2}])*Mi(x,y,f);  
%            2*pi*sx*sy           2    sx       sy 
%%% i =1,2 
%%% M1(x,y,f) = cos[2*pi*f*sqrt(x^2+y^2)]; 
%%% M2(x,y,f) = cos[2*pi*f*(x*cos(theta) + y*sin(theta)]; 
 
%% Describtion : 
 
%% I : Input image 
%% Sx & Sy : Variances along x and y-axes respectively 
%% f : The frequency of the sinusoidal function 
%% theta : The orientation of Gabor filter 
 
%% G1 & G2 : The output filters as described above 
%% gabout1 & gabout2 : The output filtered images 
 
%%  Author : Ahmad poursaberi  e-mail : a.poursaberi@ece.ut.ac.ir 
%%          Faulty of Engineering, Electrical&Computer Department,Tehran 
%%          University,Iran,June 2004 
 
function [G1,G2,gabout1,gabout2] = gaborfilter(I,Sx,Sy,f,theta); 
 
if isa(I,'double')~=1  
    I = double(I); 
end 
 
for x = -fix(Sx):fix(Sx) 
    for y = -fix(Sy):fix(Sy) 
        M1 = cos(2*pi*f*sqrt(x^2+y^2)); 
        M2 = cos(2*pi*f*(x*cos(theta)+y*sin(theta))); 
        G1(fix(Sx)+x+1,fix(Sy)+y+1) = (1/(2*pi*Sx*Sy)) * exp(-.5*((x/Sx)^2+(y/Sy)^2))*M1; 
        G2(fix(Sx)+x+1,fix(Sy)+y+1) = (1/(2*pi*Sx*Sy)) * exp(-.5*((x/Sx)^2+(y/Sy)^2))*M2; 
    end 
end 
 
Imgabout1 = conv2(I,double(imag(G1)),'same'); 
Regabout1 = conv2(I,double(real(G1)),'same'); 
 
Imgabout2 = conv2(I,double(imag(G2)),'same'); 
Regabout2 = conv2(I,double(real(G2)),'same'); 
 
gabout1 = sqrt(Imgabout1.*Imgabout1 + Regabout1.*Regabout1); 
gabout2 = sqrt(Imgabout2.*Imgabout2 + Regabout2.*Regabout2);