wolffd@0: function plot_square_hhmm(ev)
wolffd@0: % Plot the square shape implicit in the evidence.
wolffd@0: % ev{i,t} is the value of node i in slice t.
wolffd@0: % The observed node contains a velocity (delta increment), which is converted
wolffd@0: % into a position.
wolffd@0: % The Q2 node specifies which model is used; each segment is color-coded
wolffd@0: % in the order red, green, blue, black.
wolffd@0: 
wolffd@0: Q1 = 1; Q2 = 2; Q3 = 3; F3 = 4; F2 = 5; Onode = 6;
wolffd@0: 
wolffd@0: delta = cell2num(ev(Onode,:)); % delta(:,t)
wolffd@0: Q2label = cell2num(ev(Q2,:)); 
wolffd@0: 
wolffd@0: T = size(delta, 2);
wolffd@0: pos = zeros(2,T+1);
wolffd@0: clf
wolffd@0: hold on
wolffd@0: cols = {'r', 'g', 'b', 'k'};
wolffd@0: boundary = 0;
wolffd@0: coli = 1;
wolffd@0: for t=2:T+1
wolffd@0:   pos(:,t) = pos(:,t-1) + delta(:,t-1);
wolffd@0:   plot(pos(1,t), pos(2,t), sprintf('%c.', cols{coli}));
wolffd@0:   if t < T
wolffd@0:     boundary = (Q2label(t) ~= Q2label(t-1));
wolffd@0:   end
wolffd@0:   if boundary
wolffd@0:     coli = coli + 1;
wolffd@0:     coli = mod(coli-1, length(cols)) + 1;
wolffd@0:   end
wolffd@0: end
wolffd@0: