% thresh.m converts an image to black and white using threshholds

F = 'party_72.png';                   % specify the file name

P = imread(F);                        % read image into M by N by 3 matrix
size(P)
class(P)

NT = 40;                              % number of threshholds

for i=0:NT,
  PBW = im2bw(P,i/NT);
  imshow(PBW)
  drawnow
  pause
end