url = 'http://geo.fsv.cvut.cz/user/gin/git1/matlab/img/';
K1 = imread(strcat(url,'soutok.jpg'));

figure(1), imshow(K1);
%{
 
 'log'       Laplacian of Gaussian filter
 'prewitt'   Prewitt horizontal edge-emphasizing filter
 'sobel'     Sobel horizontal edge-emphasizing filter
 'roberts'   specifies the Roberts method.
 'zerocross' specifies the zero-cross method.
 'canny'     Canny method
%}
[K2, trash, gv, gh] = edge(K1, 'sobel');
figure(2), imshow(K2);

