%fig915.m - Figure 9.15 Gonzales and Woods' book
% region filling example
% (C) 2003 by Yu Hen Hu
% created: 12/2/2003

clear all
A=[0 0 0 0 0 0 0
   0 0 1 1 0 0 0
   0 1 0 0 1 0 0
   0 1 0 0 1 0 0
   0 0 1 0 1 0 0
   0 0 1 0 1 0 0
   0 1 0 0 0 1 0 
   0 1 0 0 0 1 0
   0 1 1 1 1 0 0
   0 0 0 0 0 0 0];
figure(1),clf,colormap('gray')
subplot(131),imagesc(A),
Ac=ones(size(A))-A;
B=[0 1 0; 1 1 1; 0 1 0];
x=zeros(size(A)); x(3,3)=1; 
k=0; 
converged=0;
while converged==0, 
   k=k+1;
   subplot(132),imagesc(x);drawnow
   xnew=double(and(dilate(x,B),Ac));
   if sum(sum(xnew-x))==0, converged=1; 
   else x=xnew;
      disp(['iteration # ' int2str(k)]);
   end
   pause(.5)
end
y=x+A;
subplot(133),imagesc(y);