1 %% Copyright (c) 2011, INRA
2 %% 2007-2011, David Legland <david.legland@grignon.inra.fr>
3 %% 2011 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
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35 %% @deftypefn {Function File} {@var{circle} = } enclosingCircle (@var{pts})
36 %% Find the minimum circle enclosing a set of points.
38 %% CIRCLE = enclosingCircle(POINTS);
39 %% compute cirlce CIRCLE=[xc yc r] which enclose all points POINTS given
43 %% Rewritten from a file from
45 %% which was rewritten from a Java applet by Shripad Thite :
46 %% @url{http://heyoka.cs.uiuc.edu/~thite/mincircle/}
48 %% @seealso{circles2d, points2d, boxes2d}
51 function circle = enclosingCircle(pts)
53 % works on convex hull : it is faster
54 pts = pts(convhull(pts(:,1), pts(:,2)), :);
56 circle = recurseCircle(size(pts, 1), pts, 1, zeros(3, 2));
60 function circ = recurseCircle(n, p, m, b)
61 % n: number of points given
62 % m: an argument used by the function. Always use 1 for m.
63 % bnry: an argument (3x2 array) used by the function to set the points that
64 % determines the circle boundry. You have to be careful when choosing this
65 % array's values. I think the values should be somewhere outside your points
66 % boundary. For my case, for example, I know the (x,y) I have will be something
67 % in between (-5,-5) and (5,5), so I use bnry as:
74 circ = createCircle(b(1,:), b(2,:), b(3,:));
83 c = (b(1,:) + b(2,:))/2;
84 circ = [c distancePoints(b(1,:), c)];
89 if distancePoints(p(i,:), circ(1:2)) > circ(3)
90 if sum(b(:,1)==p(i,1) & b(:,2)==p(i,2)) == 0
92 circ = recurseCircle(i, p, m+1, b);