matlab实现gabor filter (1)

在 matlab中进行计算gabor filter，自己一步步的构建滤波器矩阵：

 

先构建gabor滤波器，然后和需要进行滤波的图像进行卷积

 

代码中的size用来确定gabor filter卷积模板窗口大小。但是这里的size的卷积模板有点偏小，一般都是乘上个系数，或者4或者8.

 

% GABORFILTER Bi-dimensional Gabor filter with DC component compensation.%   [G,GABOUT]=GABORFILTER(I,S,F,W,P) filters the input image I with the 2D%   Gabor filter G described by the parameters S, F, W and P to create the %   output filtered image GABOUT.%   This version of the 2D Gabor filter is basically a bi-dimensional %   Gaussian function centered at origin (0,0) with variance S modulated by%   a complex sinusoid with polar frequency (F,W) and phase P described by %   the following equation:%%   G(x,y,S,F,W,P)=k*Gaussian(x,y,S)*(Sinusoid(x,y,F,W,P)-DC(F,S,P)),%   where:                        %       Gaussian(x,y,S)=exp(-pi*S^2*(x^2+y^2))%       Sinusoid(x,y,F,W,P)=exp(j*(2*pi*F*(x*cos(W)+y*sin(W))+P)))%       DC(F,S,P)=exp(-pi*(F/S)^2+j*P)%%   PS: The term DC(F,S,P) compensates the inherent DC component produced %   by the Gaussian envelop as shown by Movellan in [1].%% Tips:%       1) To get the real part and the imaginary part of the complex %       filter output use real(gabout) and imag(gabout), respectively;% %       2) To get the magnitude and the phase of the complex filter output %       use abs(gabout) and angle(gabout), respectively.%%   References:%       [1] Movellan, J. R. - Tutorial on Gabor Filters. Tech. rep., 2002.function [G,GABOUT]=gabor_a(I,S,F,W,P)if isa(I,'double')~=1    I=double(I);endsize=fix(1.5/S); % exp(-1.5^2*pi) < 0.1%%k=2*pi*S^2;%F=S^2/sqrt(2*pi);k=1;for x=-size:size    for y=-size:size        G(size+x+1,size+y+1)=k*exp(-pi*S^2*(x*x+y*y))*...            (exp(j*(2*pi*F*(x*cos(W)+y*sin(W))+P))-exp(-pi*(F/S)^2+j*P));    endendGABOUT=conv2(I,double(G),'same');