function [cost] = transition_cost(ii,jj, iim1,jjm1, reference_pattern, test_pattern)
% TRANSITION_COST - computes the edit distance using dynamic programming
% 
% Written by:
% -- 
% John L. Weatherwax                2005-08-04
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

if( ii-1 == iim1 && jj-1 == jjm1 ) % a diagonal transition... 
  if( reference_pattern(iim1) == test_pattern(jjm1) )
    cost = 0;
  else 
    cost = 1;
  end
elseif( ii-1==iim1 && jj==jjm1 ) % a horizontal transition... 
  cost = 1;
elseif( ii==iim1 && jj-1==jjm1 ) % a vertical transition... 
  cost = 1;
end