function image_out = BOGaussFiltering(image_in, L, dir, sigma)
% BOGaussFiltering - filtering 2D image with 2D Gauss kernel
% 
% Boguslaw Obara, http://boguslawobara.net/
%
% Help: 
%       image_out = BOGaussFiltering(image_in)
%       'image_in'  - input 2D image
%       'L'         - input length of kernel
%       'dir'       - input number of directions value
%       'sigma'     - input sigma value
%       'image_out' - output 2D image
% Example:
%       image_in=imread('BOGaussFiltering_image_in.bmp');
%       image_in=image_in(:,:,1);
%       L=5.0; dir=12; sigma=1.0;
%       image_out = BOGaussFiltering(image_in, L, dir, sigma);
%       imagesc(image_out), colormap gray;
%
% Version:
%   0.1 - 24/09/2005 First implementation

%% Filtering
theta=0.0;
image_out=zeros(size(image_in),class(image_in));
for i=0:dir
    theta=theta+pi/dir;
    se=BOGaussKernel(L,theta,sigma);
    image_f=imfilter(image_in,se,'conv','replicate');
    image_out=max(image_out,image_f);
end
%%
end