function x=imfill(A,p,B)
% Usage: x=imfill(A,p,B)
% morphological region filling
% A is a binary image which has a region to be filled
% p: is a coordinate 2 x 1 vector
%       within a region to be filled in x
% B: (optional) a structure element to be used
%   default: cross [0 1 0; 1 1 1; 0 1 0]
% (C) 2006 by Yu Hen Hu
% created: 12/19/2006

if nargin<3, B= [0 1 0; 1 1 1; 0 1 0]; end
x=zeros(size(A)); % same size as A matrix
x(p(1), p(2))=1; % make sure starting point = 1
Ac=xor(A,ones(size(A)));
done=0; k=0; kmax=max(size(A)); % maximum # of iterations
while done==0, % while not done
   k=k+1;
   xnew=and(Ac,dilate(x,B));
   if xnew==x, done=1; 
   else
      x=xnew; 
      if k==kmax, % but done=0
         disp('does not converge!');
         done=1;
      end
   end
end