restructuring - copied private function to utilities, since it is used in tutorial documentation

git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@9860 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0

Author: robertoostenveld

utilities/strel_bol.m

@@ -0,0 +1,22 @@
+function se = strel_bol(r)
+
+% STREL_BOL constructs a 3D sphere with the specified radius
+% that can be used as structural element in 3D image processing
+%
+% See STREL, IMERODE, IMDILATE (image processing toolbox)
+
+dim = [2*r+1, 2*r+1, 2*r+1];
+se  = zeros(dim);
+for i=1:dim(1)
+  for j=1:dim(2)
+    for k=1:dim(3)
+      x = i-1-r;
+      y = j-1-r;
+      z = k-1-r;
+      if norm([x y z])<=r
+        se(i,j,k) = 1;
+      end
+    end
+  end
+end
+