%!test
%! In = zeros(5,5);
%! In(3,3) = 1;
%! E = [ 0 0 0 0 0 
%!       0 0 1 0 0
%!       0 1 0 1 0  
%!       0 0 1 0 0
%!       0 0 0 0 0];
%! assert (edge(In),logical(E));
%! assert (edge(In, "sobel"),logical(E));
%! assert (edge(In, "sobel", 0),logical(E));
%! assert (edge(In, "sobel", 1),logical(zeros(5,5)));
%! V = [ 0 0 0 0 0 
%!       0 1 0 1 0
%!       0 1 0 1 0  
%!       0 1 0 1 0
%!       0 0 0 0 0];
%! assert (edge(In, "sobel", 0, 'vertical'),logical(V));
%! H = [ 0 0 0 0 0 
%!       0 1 1 1 0
%!       0 0 0 0 0  
%!       0 1 1 1 0
%!       0 0 0 0 0];
%! assert (edge(In, "sobel", 0, 'horizontal'),logical(H));
%! V = zeros(5,5);
%! V(3,2) = 1; V(3,4) = 1;
%! assert (edge(In, "sobel", [], 'vertical'),logical(V));
%! H = zeros(5,5);
%! H(2,3) = 1; H(4,3) = 1;
%! assert (edge(In, "sobel", [], 'horizontal'),logical(H));

