How to create 64 Gabor features at each scale and orientation in the spatial and frequency domain

Question

Normally, a Gabor filter, as its name suggests, is used to filter an image and extract everything that it is oriented in the same direction of the filtering.

Answer 1

phi = ij*pi/4; % ij = 0, 1, 2, 3
theta = 3;
sigma = 0.65*theta;
filterSize = 7;   % 7:2:37

G = zeros(filterSize);


for i=(0:filterSize-1)/filterSize
    for j=(0:filterSize-1)/filterSize
        xprime= j*cos(phi);
        yprime= i*sin(phi);
        K = exp(2*pi*theta*sqrt(-1)*(xprime+ yprime));
        G(round((i+1)*filterSize),round((j+1)*filterSize)) =...
           exp(-(i^2+j^2)/(sigma^2))*K;
    end
end