% comparahist: compares histograms; S. Mann
% see also Contrast Limited Adaptive Histogram Specification (local stats...?)

frame1=13
frame2=16

eval(sprintf('image1=loadpnm(''s%03d.pgm'');',frame1));
eval(sprintf('image2=loadpnm(''s%03d.pgm'');',frame2));

h1=hist256(image1);
h2=hist256(image2);
x=0:255;
subplot(221); plot(x,h1,x,h2);

H1=cumsum(h1);
H2=cumsum(h2);
subplot(222); plot(x,H1,x,H2);